FN Thomson Reuters Web of Knowledge
VR 1.0
PT J
AU Trujillo, M. E.
Hirales, D.
Rincon, M. E.
Hinojosa, J. F.
Leyva, G. L.
Castillon, F. F.
TI TiO2/clinoptilolite composites for photocatalytic degradation of anionic
and cationic contaminants
SO JOURNAL OF MATERIALS SCIENCE
VL 48
IS 19
BP 6778
EP 6785
DI 10.1007/s10853-013-7482-7
PD OCT 2013
PY 2013
AB The present work aims to study the bulk and surface properties of the TiO2/clinoptilolite composite on the crystalline structure, superficial area, bandgap energy, zeta potential, particle size distribution, and chemical composition; in order to analyze the effect of the clinoptilolite proportion in the photocatalytic degradation of pollutants. TiO2/clinoptilolite composites were prepared by adding different mass proportions of clinoptilolite to a sol-gel bath containing TiCl4 as the titania precursor. Surface charge studies explain the larger sensitivity to composite ratio observed in the photocatalytic degradation of anionic pollutants than in cationic dyes. An optimum TiO2/clinoptilolite ratio of 90/10 was found to be the most efficient in terms of lower tendency to agglomeration, largest surface area, and increased crystallite size. Improvement in composite surface area occurs only at low clinoptilolite wt% and seems to be caused by lower agglomeration of nanometric TiO2 and acid-induced porosity in the
zeolite.
SN 0022-2461
UT WOS:000321921300032
ER
PT J
AU Asgari, Nazli
Haghighi, Mohammad
Shafiei, Sirous
TI Synthesis and physicochemical characterization of nanostructured
CeO2/clinoptilolite for catalytic total oxidation of xylene at low
temperature
SO ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY
VL 32
IS 3
BP 587
EP 597
DI 10.1002/ep.11669
PD OCT 2013
PY 2013
AB A series of nanostructured CeO2/Clinoptilolite catalysts with different
loadings of ceria were prepared by redox reaction followed by wet
impregnation method and tested for oxidation of xylene. The catalysts
were characterized by XRD, FESEM, BET, FTIR, and TG-DTG analysis. XRD
data confirmed the formation of CeO2 as the crystalline phase with an
average crystallite size of about 11.6 nm for three ceria loading of 10,
20, and 30%. FESEM and size distribution analyses showed that
nanocatalysts have nanometric particles with an average size of 37.46
nm. Specific surface analysis revealed that the synthesized
nanocatalysts had large enough surface area for catalytic oxidation of
p-xylene. Furthermore, the results showed that the catalytic performance
of the supported CeO2 catalysts was much higher than that of treated
clinoptilolite, in particular, CeO2 (30%)/Clinoptilolite exhibited the
highest conversion, 98% at 350 degrees C. It is observed that increasing
both the xylene concentration and GHSV results in decreasing of the
xylene conversion; however, even at higher concentrations of xylene
(3000 ppm), the nanostructured catalyst has still enough destruction
ability to reduce the pollutant. A simplified reaction mechanism was
proposed with respect to the behavior of adsorbed species on the
catalyst surface to clarify the path through which the reaction
components interact with each other. (c) 2012 American Institute of
Chemical Engineers Environ Prog, 32: 587-597, 2013
TC 0
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ZS 0
Z9 0
SN 1944-7442
UT WOS:000321697000022
ER
PT J
AU Nezamzadeh-Ejhieh, Alireza
Moazzeni, Neda
TI Sunlight photodecolorization of a mixture of Methyl Orange and
Bromocresol Green by CuS incorporated in a clinoptilolite zeolite as a
heterogeneous catalyst
SO JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
VL 19
IS 5
BP 1433
EP 1442
DI 10.1016/j.jiec.2013.01.006
PD SEP 25 2013
PY 2013
AB Photocatalytic activity of CuS incorporated into an Iranian
clinoptilolite (CuS-Cp) was studied for decolorization of a mixture of
Methyl Orange and Bromocresol Green under sunlight irradiation. All
samples were characterized by XRD, FTIR, DRS and TG/DTG techniques. The
effect of some key experimental parameters such as: amount of the
catalyst (0.05-5 g L-1), initial concentration of dyes (5-30 mg L-1),
solution pH (1-11) and also dosage of H2O2 and KBrO3 was studied on the
decolorization extent. The extent of decolorization was estimated from
the residual concentration by spectrophotometrically and it was
confirmed by the reduction of chemical oxygen demand (COD). (c) 2013 The
Korean Society of Industrial and Engineering Chemistry. Published by
Elsevier B.V. All rights reserved.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1226-086X
UT WOS:000322943600003
ER
PT J
AU Shi, Mo
Wang, Zhengfang
Zheng, Zheng
TI Effect of Na+ impregnated activated carbon on the adsorption of NH4+-N
from aqueous solution
SO JOURNAL OF ENVIRONMENTAL SCIENCES-CHINA
VL 25
IS 8
BP 1501
EP 1510
DI 10.1016/S1001-0742(8)60227-7
PD AUG 1 2013
PY 2013
AB Two kinds of activated carbons modified by Na+ impregnation after
pre-treatments involving oxidation by nitric acid or acidification by
hydrochloric acid (denoted as AC/N-Na and AC/HCl-Na, respectively), were
used as adsorbents to remove NH4+-N. The surface features of samples
were investigated by BET, SEM, XRD and FT-IR. The adsorption experiments
were conducted in equilibrium and kinetic conditions. Influencing
factors such as initial solution pH and initial concentration were
investigated. A possible mechanism was proposed. Results showed that
optimal NH4+-N removal efficiency was achieved at a neutral pH condition
for the modified ACs. The Langmuir isotherm adsorption equation provided
a better fit than other models for the equilibrium study. The adsorption
kinetics followed both the pseudo second-order kinetics model and
intra-particle kinetic model. Chemical surface analysis indicated that
Na+ ions form ionic bonds with available surface functional groups
created by pre-treatment, especially oxidation by nitric acid, thus
increasing the removal efficiency of the modified ACs for NH4+-N
Na+-impregnated ACs had a higher removal capability in removing NH4+-N
than unmodified AC, possibly resulting from higher numbers of surface
functional groups and better intra-particle diffusion. The good fit of
Langmuir isotherm adsorption to the data indicated the presence of
monolayer NH4+-N adsorption on the active homogenous sites within the
adsorbents. The applicability of pseudo second-order and intra-particle
kinetic models revealed the complex nature of the adsorption mechanism.
The intra-particle diffusion model revealed that the adsorption process
consisted not only of surface adsorption but also intra-particle
diffusion.
TC 0
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Z9 0
SN 1001-0742
UT WOS:000323356700001
ER
PT J
AU Rajic, Nevenka
Logar, Natasa Zabukovec
Recnik, Aleksander
El-Roz, Mohamad
Thibault-Starzyk, Frederic
Sprenger, Paul
Hannevold, Lenka
Andersen, Anne
Stocker, Michael
TI Hardwood lignin pyrolysis in the presence of nano-oxide particles
embedded onto natural clinoptilolite
SO MICROPOROUS AND MESOPOROUS MATERIALS
VL 176
BP 162
EP 167
DI 10.1016/j.micromeso.2013.04.005
PD AUG 2013
PY 2013
AB In this study the catalytic activity of Na-rich and MO-containing
natural clinoptilolite (MO - nanopartides of NiO, ZnO, or Cu2O) was
studied in the pyrolysis of hardwood lignin. The clinoptilolite samples
exhibit different catalytic activities which depend mainly on the type
of the nano-oxide. The presence of nano-oxides did not affect the
porosity of the clinoptilolite framework but influenced its acidity.
However, it seems that acidity of the lattice did not influence the
catalytic activity of the clinoptilolite in the pyrolisis of hardwood
lignin. The number of Lewis acid sites increased significantly for the
ZnO- and Cu2O-containing clinoptilolite whereas for the NiO-sample it
did not change appreciably in comparison to the parent zeolite. The
amount of phenols in the as-produced bio-oil varies from 39% for
ZnO-clinoptilolite, 43% for Na-rich clinoptilolite, to 50 and 54% for
Cu2O- and NiO-containing samples, respectively. The highest yield of
phenols obtained in the presence of NiO-containing clinoptilolite is
ascribed to a synergetic interaction of the clinoptilolite lattice and
nano-NiO particles. (C) 2013 Elsevier Inc. All rights reserved.
RI Thibault-Starzyk, Frederic/B-5606-2008
OI Thibault-Starzyk, Frederic/0000-0002-8095-0860
TC 0
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Z8 0
ZS 0
Z9 0
SN 1387-1811
UT WOS:000320422400021
ER
PT J
AU Khoshbin, Reza
Haghighi, Mohammad
TI Preparation and Catalytic Performance of CuO-ZnO-Al2O3/Clinoptilolite
Nanocatalyst for Single-Step Synthesis of Dimethyl Ether from Syngas as
a Green Fuel
SO JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
VL 13
IS 7
BP 4996
EP 5003
DI 10.1166/jnn.2013.7579
PD JUL 2013
PY 2013
AB Direct conversion of syngas to dimethyl ether was successfully carried
out over a clinoptilolite supported nanocatalyst modified by NH4Cl. A
series of bifunctional nanocatalysts, CuO-ZnO-Al2O3 (CZA) over
Clinoptilolite with different loading of CZA, were prepared via
coprecipitation method and their catalytic performance were compared in
a fixed-bed high pressure reactor. The catalysts were characterized by
XRD, BET, FESEM, FTIR and TPD-NH3 techniques. The physicochemical
analysis showed that with NH4Cl treatment, the specific surface area of
clinoptilolite increased obviously, while its crystallinity decreased
slightly. It was found that the crystallinity of clinoptilolite was
dramatically changed, whereas crystallinity of CuO has not been
influenced significantly by the increase of CZA content. Moreover, with
increasing the CZA/Clinoptilolite ratio, the specific surface area of
nanocatalysts decreased. It is shown that the CZA particle size is
distributed between 30.5-131.2 nm with an average size of 70.6 nm in
which 77.8% of the particles are in the range of below 100 nm. The
TPD-NH3 patterns showed that the number of the acid sites of the
nanocatalysts decreased with the increase the CZA content. The influence
of reaction pressure was investigated, confirming that the optimal
reaction pressure for this catalyst was 40 bar. The catalytic
performance is shown that the CZA/Clinoptilolite = 2 nanocatalyst had
higher activity, selectivity due to its higher acidic sites.
RI Venkatachalam, Chandrasekaran/G-4047-2013
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1533-4880
UT WOS:000320632100056
ER
PT J
AU Emiroglu, A. O.
Eldogan, O.
TI Reduction of NOx in Gasoline Engine Exhaust on Ni-exchanged
Clinoptilolite
SO ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS
VL 35
IS 12
BP 1140
EP 1149
DI 10.1080/15567036.2010.518222
PD JUN 15 2013
PY 2013
AB Contrary to traditional three-way catalysts, high success is obtained in
the removal of NOx with selective catalytic reduction catalysts with
lean combustion conditions used in the oxygen excess. A zeolite-based
catalyst is used commonly to control NOx in selective catalytic
reduction applications in lean combustion gasoline engines. In this
study, the catalyst was prepared by loading nickel as the reducing
agent, over the clinoptilolite type of natural zeolite exposed to
various chemical processes, to selectively reduce the nitrogen oxides
especially in the lean combustion conditions with the hydrocarbons in
the exhaust gas. According to experimental results, the maximum
conversion efficiency is 34% for Ni-NZ.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1556-7036
UT WOS:000318764200006
ER
PT J
AU Jamalzadeh, Zeinab
Haghighi, Mohammad
Asgari, Nazli
TI Synthesis, physicochemical characterizations and catalytic performance
of Pd/carbon-zeolite and Pd/carbon-CeO2 nanocatalysts used for total
oxidation of xylene at low temperatures
SO FRONTIERS OF ENVIRONMENTAL SCIENCE & ENGINEERING
VL 7
IS 3
BP 365
EP 381
DI 10.1007/s11783-013-0520-5
PD JUN 2013
PY 2013
AB In this work, xylene removal from waste gas streams was investigated via
catalytic oxidation over Pd/carbon-zeolite and Pd/carbon-CeO2
nanocatalysts. Activated carbon was obtained from pine cone chemically
activated using ZnCl2 and modified by H3PO4. Natural zeolite of
clinoptilolite was modified by acid treatment with HCl, while nano-ceria
was synthesized via redox method. Mixed supports of carbon-zeolite and
carbonceria were prepared and palladium was dispersed over them via
impregnation method. The prepared samples were characterized by X-ray
diffraction (XRD), field emission scanning electron microscopy (FESEM),
Brunauer-Emmett-Teller surface area (BET), Fourier transform infrared
spectroscopy (FTIR) and thermogravimetric (TG) techniques.
Characterization of nanocatalysts revealed a good morphology with an
average particle size in a nano range, and confirmed the formation of
nano-ceria with an average crystallite size below 60 nm. BET analysis
indicated a considerable surface area for catalysts (similar to 1000
m(2)center dot g(-1)). FTIR patterns demonstrated that the surface
groups of synthesized catalysts are in good agreement with the patterns
of materials applied in catalyst synthesis. The performance of catalysts
was assessed in a low-pressure catalytic oxidation pilot in the
temperature range of 100A degrees C-250A degrees C. According to the
reaction data, the synthesized catalysts have been shown to be so
advantageous in the removal of volatile organic compounds (VOCs),
representing high catalytic performance of 98% for the abatement of
xylene at 250A degrees C. Furthermore, a reaction network is proposed
for catalytic oxidation of xylene over nanocatalysts.
TC 0
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SN 2095-2201
UT WOS:000319612800006
ER
PT J
AU Taghavi, Firouzeh
Falamaki, Cavus
Shabanov, Alimemad
Bairami, Leila
Seyyedi, Mina
TI Clinoptilolite, kieselguhr and alpha-alumina supported nano-nickel
boride catalysts for the production of high purity p-aminophenol through
p-nitrophenol hydrogenation: a comparative study
SO REACTION KINETICS MECHANISMS AND CATALYSIS
VL 109
IS 1
BP 91
EP 104
DI 10.1007/s11144-013-0539-4
PD JUN 2013
PY 2013
AB The morphology of supported nickel boride nanoparticles depends strongly
on the exposed surface cation exchange property of the support. Despite
having a substantially higher loading of nickel boride, the alpha-Al2O3
supported catalyst exhibits a significantly lower catalytic activity for
the hydrogenation of p-nitrophenol. Use of a supporting material like
clinoptilolite allows the re-use of the catalyst up to three times.
However, the catalytic activity decreases after each hydrogenation
process. Unsupported nickel boride and alpha-Al2O3 supported nickel
boride result in unwanted trace impurities in the final p-aminophenol
crystalline product. Such impurities are absent using clinoptilolite and
kieselguhr supports.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1878-5190
UT WOS:000318873400008
ER
PT J
AU Verboekend, Danny
Keller, Tobias C.
Milina, Maria
Hauert, Roland
Perez-Ramirez, Javier
TI Hierarchy Brings Function: Mesoporous Clinoptilolite and L Zeolite
Catalysts Synthesized by Tandem Acid-Base Treatments
SO CHEMISTRY OF MATERIALS
VL 25
IS 9
BP 1947
EP 1959
DI 10.1021/cm4006103
PD MAY 14 2013
PY 2013
AB Hierarchical clinoptilolite and L zeolites are prepared using optimized
tandem dealumination desilication treatments. The main challenge in the
postsynthetic modification of these zeolites is the high Al content,
requiring a tailored clealumination prior to the desilication step. For
natural clinoptilolite, sequential acid treatments using aqueous HCl
solutions were applied, while for L a controlled dealumination using
ammonium hexafluorosilicate is required. Subsequent desilication by NaOH
treatment yields mesopore surfaces of up to 4-fold (clinoptilolite, 64
m(2) g(-1), L, 135 m(2) g(-1)) relative to the parent zeolite
(clinoptilolite, 15 m(2) g(-1); L 45 m(2) g(-1)). A thorough
characterization sheds light on the composition, crystallinity,
porosity, morphology, coordination, and acidity of the modified
clinoptilolite and L zeolites. It is elaborated that, besides the degree
of dealumination, the resulting Al distribution is a critical
precondition for the following mesopore formation by desilication.
Adsorption experiments of Cu2+ and methylene blue from aqueous solutions
and the catalytic evaluation in alkylations and Knoevenagel condensation
evidence the superiority of the hierarchical zeolites, as compared to
their purely microporous counterparts. Finally, the postsynthetic routes
for clinoptilolite and L are generalized with other recently reported
modification strategies, and presented in a comprehensive overview.
TC 1
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Z9 1
SN 0897-4756
UT WOS:000319184600064
ER
PT J
AU Gercel, H. F.
TI The Effects of Different Catalysts on the Pyrolysis of Thistle,
Onopordum Acanthium L.
SO ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS
VL 35
IS 9
BP 791
EP 799
DI 10.1080/15567036.2010.509082
PD MAY 1 2013
PY 2013
AB Fixed-bed fast pyrolysis experiments have been conducted on a sample of
thistle, Onopordum Acanthium L. The experiments were performed in a
fixed-bed tubular pyrolysis reactor to investigate the effects of
sweeping gas flow rate and types of catalysts on the pyrolysis product
yields. The optimal sweeping gas flow rate is 100 cm3 min1. In order to
increase the oil yield, biomass pyrolysis experiments were performed in
a fixed bed reactor with two selected catalysts, namely sepiolite and
clinoptilolite. All experiments were conducted in a nitrogen atmosphere
with a heating rate of 300 degrees C min1, pyrolysis temperature of 550
degrees C, and mean particle size of +0.60.85 mm. In the experiments,
all the catalysts were used with various percentages, and the effects of
the variable catalysts on the yields and chemical composition of the
oils obtained were investigated. Oil yield reached 29.5% with the use of
sepiolite and 32.1% with clinoptilolite, while it was only 18.9% without
a catalyst. Chromatographic and spectroscopic studies on the pyrolytic
oil showed that the oil obtained from thistle could be used as a
renewable fuel and chemical feedstock.
TC 0
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Z8 0
ZS 0
Z9 0
SN 1556-7036
UT WOS:000316393000001
ER
PT J
AU Asgari, Nazli
Haghighi, Mohammad
Shafiei, Sirous
TI Synthesis and physicochemical characterization of nanostructured
Pd/ceria-clinoptilolite catalyst used for p-xylene abatement from waste
gas streams at low temperature
SO JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
VL 88
IS 4
BP 690
EP 703
DI 10.1002/jctb.3887
PD APR 2013
PY 2013
AB BACKGROUND: The effect of Pd loading, xylene concentration and GHSV on
xylene oxidation was tested over Pd/CeO2(30%)-clinoptilolite
nanocatalysts at low temperatures. The catalysts were prepared by acid
treatment of clinoptilolite, followed by the incipient wetness method of
synthesized ceria and modified clinoptilolite in PdCl2 solution. The
synthesized nanocatalysts were characterized by XRD, FESEM, EDAX, TEM,
BET, FTIR and TG-DTG analysis. RESULTS: The XRD patterns confirmed the
formation of crystalline ceria with an average crystallite size of 11.8
nm. FESEM images showed nanostructures in cavities of natural zeolite,
brought about by ceria incorporation and acid activation. TEM analysis
showed high dispersion of Pd with a size distribution between 6.6 and
36.7 nm. The quantitative analysis showed that the specific surface area
of Pd(1%)/CeO2(30%)-clinoptilolite was 77 m2 g1. The results showed that
Pd(1%)/CeO2(30%)-clinoptilolite is the most appropriate catalyst, with
the conversion more than 90% at 275 degrees C. CONCLUSIONS: Experimental
results established effective performance and durability for the
catalysts. As a result, clinoptilolite modification and ceria
incorporation significantly altered the samples' morphology at
nanoscale, improving the structure of composites and distribution of
noble metals. A reaction path was suggested based on the
adsorption-migration of species to reveal the mechanism of p-xylene
oxidation over nanocatalysts. (c) 2012 Society of Chemical Industry
TC 1
ZB 0
Z8 1
ZS 0
Z9 1
SN 0268-2575
UT WOS:000316627600023
ER
PT J
AU Ilinoiu, Elida Cristina
Pode, Rodica
Manea, Florica
Colar, Liliana Andreea
Jakab, Agnes
Orha, Corina
Ratiu, Cornelia
Lazau, Carmen
Sfarloaga, Paula
TI Photocatalytic activity of a nitrogen-doped TiO2 modified zeolite in the
degradation of Reactive Yellow 125 azo dye
SO JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS
VL 44
IS 2
BP 270
EP 278
DI 10.1016/j.jtice.2012.09.006
PD MAR 2013
PY 2013
AB In this study, the hybrid material based on natural zeolite modified
with nitrogen-doped TiO2 photocatalyst (Z-TiO2-N) was synthesized by
solid-state reaction under microwave-assisted hydrothermal conditions.
The surface characterization of hybrid material has been investigated by
X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy
dispersive X-ray (EDX) analysis, and FT-IR spectroscopy. The
photocatalytic activity of Z-TiO2-N photocatalyst under UV and VIS
irradiation was determined for the degradation of Reactive Yellow 125
CRY 125) dye solution. Also, UV-VIS diffuse reflectance (DRUV-VIS)
spectroscopy was used to determine the light absorption properties of
the hybrid material. The operational conditions using photocatalyst dose
of 1 g/L at pH 3 were established as optimal conditions for
photocatalytic application in RY 125 dye solution degradation. The
experimental studies revealed that the degradation efficiency expressed
in terms of discoloration, aromatic ring-opening and mineralization
depended strongly on the initial RY 125 dye solution concentrations. The
photocatalyst exhibited a good performance for discoloration and
aromatic-ring opening processes at all studied concentrations (25, 50
and 100 mg/L) but an effective mineralization was reached only for 25
mg/L RY 125 dye solution. Also, the degradation of low concentrations of
RY 125 dye solution was achieved using Z-TiO2-N catalyst under VIS
irradiation. (C) 2012 Taiwan Institute of Chemical Engineers. Published
by Elsevier B.V. All rights reserved.
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 1876-1070
UT WOS:000315838100020
ER
PT J
AU Nezamzadeh-Ejhieh, Alireza
Amiri, Mehdi
TI CuO supported Clinoptilolite towards solar photocatalytic degradation of
p-aminophenol
SO POWDER TECHNOLOGY
VL 235
BP 279
EP 288
DI 10.1016/j.powtec.2012.10.017
PD FEB 2013
PY 2013
AB CuO as a semiconductor as incorporated onto an Iranian natural
Clinoptilolite zeolite, was prepared by calcination of Cu(II)-ion
exchanged Clinoptilolite. The obtained composite was used as a
photocatalyst to degrade a p-aminophenol aqueous solution. All raw and
modified samples were characterized using XRD, FT-IR, BET and SEM
methods. The degradation and mineralization extents were performed by
UV-vis spectrophotometry, COD and HPLC The optimum values of the
experimental parameters which affect the degradation efficiency were
obtained as: 2.0 gL(-1) of the photocatalyst, 20 ppm of p-aminophenol
and pH 6.0. Hydrogen peroxide and potassium bromate considerably
increased the rate of degradation. Zeolite bed had considerable role in
the photodegradation efficiency, so the proposed catalyst significantly
increased the efficiency with respect to CuO and especially
Clinoptilolite alone. (c) 2012 Elsevier B.V. All rights reserved.
TC 3
ZB 1
Z8 0
ZS 0
Z9 3
SN 0032-5910
UT WOS:000316039400033
ER
PT J
AU Khoshbin, Reza
Haghighi, Mohammad
Asgari, Nazli
TI Direct synthesis of dimethyl ether on the admixed nanocatalysts of
CuO-ZnO-Al2O3 and HNO3-modified clinoptilolite at high pressures:
Surface properties and catalytic performance
SO MATERIALS RESEARCH BULLETIN
VL 48
IS 2
BP 767
EP 777
DI 10.1016/j.materresbull.2012.11.057
PD FEB 2013
PY 2013
AB The potential of clinoptilolite as a methanol dehydration catalyst in
direct conversion of syngas to dimethyl ether has been investigated. The
modified form of clinoptilolite was obtained by nitric acid treatment.
Although the physicochemical analysis showed that crystallinity of the
clinoptilolite decreased during HNO3-treatment, the specific surface
area of natural zeolite increased considerably. Size distribution
histogram of the synthesized nanocatalyst showed that the particle size
of active phase was between 28.9 and 112.9 nm with an average size of
53.9 nm. The NH3-TPD profiles showed that both the number and strength
of the acid sites of the CuO-ZnO-Al2O3/clinoptilolite nanocatalysts
decreased with increasing active phase content. Results indicated that
the optimal reaction temperature and pressure for this nanocatalysts
were 300 degrees C and 40 bar, respectively. The catalytic performance
of synthesized samples showed that the optimum CuO-ZnO-Al2O3 to
clinoptilolite ratio was 4:1, which depends on temperature and pressure.
(C) 2012 Elsevier Ltd. All rights reserved.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0025-5408
UT WOS:000315751300094
ER
PT J
AU Akgul, Murat
Ozyagci, Bensu
Karabakan, Abdulkerim
TI Evaluation of Fe- and Cr-containing clinoptilolite catalysts for the
production of camphene from alpha-pinene
SO JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
VL 19
IS 1
BP 240
EP 249
DI 10.1016/j.jiec.2012.07.024
PD JAN 25 2013
PY 2013
AB The catalytic properties of the Cr3+- and Fe3+-loaded clinoptilolites
were screened in the liquid-phase isomerization of alpha-pinene and the
major products were found to be camphene and limonene. Selectivity to
camphene was superior for the 0.7Fe-CL catalyst than those observed for
the Raw-CL and 0.4Cr-CL catalyst. Over raw clinoptilolite, the
proportion of limonene and other isomers reached similar to 65% while it
was similar to 15% with 0.7Fe-CL and similar to 56% with 0.4Cr-CL. The
results also show that the selectivity to camphene increases with
increasing reaction time reaching up to about similar to 72% at 428 K
over 0.7Fe-CL catalyst. (C) 2012 The Korean Society of Industrial and
Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1226-086X
UT WOS:000312764700034
ER
PT J
AU Lima, Enrique
Guerra, Roberto
Lara, Victor
Guzman, Ariel
TI Gold nanoparticles as efficient antimicrobial agents for Escherichia
coli and Salmonella typhi
SO CHEMISTRY CENTRAL JOURNAL
VL 7
AR 11
DI 10.1186/1752-153X-7-11
PD JAN 19 2013
PY 2013
AB Background: It is imperative to eliminate bacteria present in water in
order to avoid problems in healthy. Escherichia coli and Salmonella
typhi bacteria are two common pollutants and they are developing
resistance to some of the most used bactericide. Therefore new biocide
materials are being tested. Thus, gold nanoparticles are proposed to
inhibit the growth of these two microorganisms.
Results: Gold nanoparticles were supported onto clinoptilolite,
mordenite and faujasite zeolites. Content of gold in materials varied
between 2.3 and 2.8 wt%. The size, dispersion and roughness of gold
nanoparticles were highly dependent of the zeolite support. The
faujasite support was the support where the 5 nm nanoparticles were
highly dispersed. The efficiency of gold-zeolites as bactericides of
Escherichia coli and Salmonella typhi was determined by the zeolite
support.
Conclusions: Gold nanoparticles dispersed on zeolites eliminate
Escherichia coli and Salmonella typhi at short times. The biocidal
properties of gold nanoparticles are influenced by the type of support
which, indeed, drives key parameters as the size and roughness of
nanoparticles. The more actives materials were pointed out Au-faujasite.
These materials contained particles sized 5 nm at surface and eliminate
90-95% of Escherichia coli and Salmonella typhi colonies.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1752-153X
UT WOS:000315271100001
ER
PT S
AU Li, Fangfei
Xia, Maosheng
Jiang, Yinshan
BE Liu, XH
Zhang, KF
Li, MZ
TI Various morphology of hierarchical pore-structured compound:
MCM-41/diatomite and its adsorption behavior for methylene blue
SO MATERIAL DESIGN, PROCESSING AND APPLICATIONS, PARTS 1-4
SE Advanced Materials Research
VL 690-693
BP 3533
EP 3540
DI 10.4028/www.scientific.net/AMR.690-693.3533
PD 2013
PY 2013
AB Hierarchical porous materials attract considerable attentions due to
their interesting structures and superior adsorption capabilities. In
this work, a novel macro- and meso-porous hierarchical material,
MCM-41/diatomite, has successfully been synthesized from natural
diatomite and tetraethoxysilane by basic hydrothermal method. Nitrogen
adsorption/desorption isotherms, low angle XRD and SEM analysis were
carried out to character the multiple porous structure and morphology of
MCM-41/diatomite. The resultant compound displayed high specific surface
area (862 similar to 1041 m(2)/g) and macro-meso-porous hierarchical
structure. The morphology of MCM-41/diatomite could be various, such as
worm-like, grape-like, flocky, and acaleph-like, due to different ratio
between TEOS, PEG, and NaOH. Moreover, the results of adsorption
experiments show that some of the resultant MCM-41/diatomite display
stronger adsorption capabilities than simply mesoporous MCM-41, due to
the macro-meso-porous hierarchical structure, which would further extend
the application of MCM-41/diatomite as adsorbent and catalyst support.
CT 4th International Conference on Manufacturing Science and Engineering
(ICMSE 2013)
CY MAR 30-31, 2013
CL Dalian, PEOPLES R CHINA
SP NE Univ; Harbin Inst Technol; Jilin Univ
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1022-6680
BN 978-3-03785-692-5
UT WOS:000322498601347
ER
PT S
AU Ruiz-Baltazar, A.
Esparza, R.
Perez, R.
Rosas, G.
BE Campos, RP
Cuevas, AC
Munoz, RAE
TI Synthesis of Ag nanoparticles-clinoptilolite composite by homogeneous
and heterogeneous nucleation
SO STRUCTURAL AND CHEMICAL CHARACTERIZATION OF METALS, ALLOYS AND COMPOUNDS
SE Materials Science Forum
VL 755
BP 97
EP 103
DI 10.4028/www.scientific.net/MSF.755.97
PD 2013
PY 2013
AB In this study, a natural zeolite clinoptilolite-type was impregnated
through homogeneous and heterogeneous nucleation with silver
nanoparticles. The synthesis of Ag nanoparticles was carried out by
chemical reduction of silver nitrate (AgNO3) with sodium borohydride
(NaBH4). In the case of homogeneous nucleation, colloidal solution of Ag
nanoparticles at concentrations of 1, 2 and 4 parts per million was
added and magnetically mixed with the porous material. With respect to
heterogeneous nucleation, a solution of clinoptilolite and silver
nitrate (0.01 M) was prepared and stirred; subsequently, the reduction
of Ag was possible due to the addition of an aqueous solution of sodium
borohydride. For the structural characterization, transmission electron
microscopy (TEM), X-ray diffraction (XRD) and infrared spectroscopy (IR)
techniques were carried out. The results were compared and discussed in
both types of nucleation.
CT Symposium on Structural and Chemical Characterization of Metals, Alloys
and Compounds / 21 International Materials Research Congress (IMRC 2012)
CY AUG 12-17, 2012
CL Cancun, MEXICO
SP Mexican Mat Soc; Natl Autonomous Univ Mexico; Mexican Petr Inst
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0255-5476
BN *****************
UT WOS:000321074000014
ER
PT J
AU Lin, Wei Gang
Wan, Mi Mi
Zhou, Yu
Gu, Hui Cheng
Zhou, Shi Lu
Zhu, Jian Hua
TI Novel selective catalyst derived from uniform clustered NaY zeolite
microspheres
SO JOURNAL OF MATERIALS CHEMISTRY A
VL 1
IS 23
BP 6849
EP 6857
DI 10.1039/c3ta10483d
PD 2013
PY 2013
AB The design and preparation of a new "self-protected" zeolite catalyst
are reported in this paper for the first time, in order to face the
challenges arising from environmental protection, in selective catalytic
degrading of tobacco specific nitrosamine (TSNA) carcinogens in
environmental tobacco smoke (ETS). A new method to synthesize NaY
zeolite with uniform microsphere morphology via an organic amine TMAOH
as bifunctional template is reported in this study. The spherical
zeolite is prepared by a one-step hydrothermal crystallization without
any post-treatment or other shape-directing agent. It has a rugged
surface like a cluster of crystal grains and its crystallization process
is monitored in detail by means of XRD and SEM. To assess how the
zeolite morphology affects its catalytic performance in complex systems,
this material was directly mixed with tobacco shred and added into
cigarettes to in situ degrade TSNA in smoke. As a result, the clustered
zeolite microsphere can avoid the interference of particulate matter in
smoke and shows a high selectivity in the removal of TSNA. This
synthetic method offers a novel way of preparing zeolites with a
spherical morphology, which has great potential application in the
fields of catalysis, adsorption and separation.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 2050-7488
UT WOS:000319272800019
ER
PT J
AU Nezamzadeh-Ejhieh, Alireza
Shirvani, Khodarahm
TI CdS Loaded an Iranian Clinoptilolite as a Heterogeneous Catalyst in
Photodegradation of p-Aminophenol
SO JOURNAL OF CHEMISTRY
AR 541736
DI 10.1155/2013/541736
PD 2013
PY 2013
AB Natural clinoptilolite, zeolite CdS-incorporated was prepared by ion
exchange and precipitation procedures and it was characterized by FT-IR,
XRD, and thermal methods. The prepared composite was used as a catalyst
in the photodegradation process of p-aminophenol in aqueous solution
under UV irradiation. The effect of some key operating parameters such
as catalyst dosage, temperature, the initial concentration of the
pollutant, and initial pH of the solutions on the degradation process of
the pollutant was studied. The primary objective was to determine the
optimal conditions for each of the parameters. UV-vis spectrophotometric
measurements were performed for the determination of degradation and
mineralization extents. The optimal operation parameters were found as
follows: pH 5, 17.5 mg.L-1 of catalyst loading, and 10 ppm of dye
concentration. The CdS particles out of zeolite framework do not show
significant degradation efficiency. The degradation process obeyed
first-order kinetics.
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 2090-9063
UT WOS:000311441300001
ER
PT J
AU Perez Velez, Roxana
Elizalde Gonzalez, Maria P.
Bentrup, Ursula
TI Preparation and in situ spectroscopic characterization of
Cu-clinoptilolite catalysts for the oxidative carbonylation of methanol
SO MICROPOROUS AND MESOPOROUS MATERIALS
VL 164
SI SI
BP 93
EP 98
DI 10.1016/j.micromeso.2012.06.025
PD DEC 1 2012
PY 2012
AB Cu-containing natural and synthetic clinoptilolite were prepared by Cu
cation exchange and impregnation with copper nitrate solution. The
samples were characterized and tested for the synthesis of dimethyl
carbonate. The state of Cu(I) and Cu(II) species was proved by in situ
FTIR spectroscopy using CO and NO as probe molecules. The observed bands
of vCu(I)-CO and vCu(II)-NO modes are relatively broad indicating a
location of the Cu cations at several sites in the zeolite lattice.
Cu-clinoptilolite catalysts oxidize CO and NO to a certain extent even
at room temperature where CO2 is partly captured in the zeolite
cavities.
The interaction of the catalysts with MeOH/CO/O-2 gas mixtures was
studied by in situ FTIR spectroscopy and operando DRIFTS/MS. Oxygenated
products like dimethoxy methane and methyl formate were found besides
CO2 in the gas phase while formate, methyl formate and methoxy species
were adsorbed at the catalyst surface. In contrast to Cu-Y catalysts no
dimethyl carbonate formation could be detected. Obviously, the different
channel system of clinoptilolite and the distinct lower BET surface area
are disadvantageous concerning dimethyl carbonate formation. (C) 2012
Elsevier Inc. All rights reserved.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1387-1811
UT WOS:000310770100014
ER
PT J
AU Alamolhoda, S.
Kazemeini, M.
Zaherian, A.
Zakerinasab, M. R.
TI Reaction kinetics determination and neural networks modeling of methanol
dehydration over nano gamma-Al2O3 catalyst
SO JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
VL 18
IS 6
BP 2059
EP 2068
DI 10.1016/j.jiec.2012.05.027
PD NOV 25 2012
PY 2012
AB In this research nano gamma-Al2O3 catalyst was synthesized through
precipitation process then characterized and utilized for methanol
dehydration reaction in a slurry batch reactor in route to the indirect
synthesis of the dimethyl ether (DME). In this venue, effects of the key
parameters on methanol conversion and catalyst stability were
investigated. Moreover, the internal and external mass transfer
resistances were eliminated; hence the intrinsic kinetics controlled the
reaction. Therefore, the optimum conditions for temperature, methanol
concentration, catalyst mass and stirrer speed were determined to be 300
degrees C, 1.18 mol/l, 1.5 g and 1100 rpm, respectively. Next, different
reaction rate equations from literature were applied to the measured
experimental data where their generality compared to a new reaction rate
equation examined. Ultimately, artificial neural networks applied to
determine a model for the reaction rate estimation. It has been shown
that the proposed reaction rate equation might be used rather
satisfactorily to provide a base model for the neural networks;
consequently a very good proximity to the reaction dynamics resulted.
(C) 2012 The Korean Society of Industrial and Engineering Chemistry.
Published by Elsevier B.V. All rights reserved.
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 1226-086X
UT WOS:000311005500029
ER
PT J
AU Chiang, Yi Wai
Ghyselbrecht, Karel
Santos, Rafael M.
Meesschaert, Boudewijn
Martens, Johan A.
TI Synthesis of zeolitic-type adsorbent material from municipal solid waste
incinerator bottom ash and its application in heavy metal adsorption
SO CATALYSIS TODAY
VL 190
IS 1
BP 23
EP 30
DI 10.1016/j.cattod.2011.11.002
PD AUG 1 2012
PY 2012
AB Municipal solid waste incinerator (MSWI) bottom ash (BA) was converted
to zeolitic-type adsorbent materials by hydrothermal conversion under
strongly alkaline conditions. The conversion product was determined to
be a mixture of sodium aluminum silicate hydrate (SASH) (Na2O center dot
Al2O3 center dot 1.68SiO(2)center dot 1.73H(2)O) and tobermorite
(Ca5Si6O16(OH)(2 center dot)4H(2)O). The BET specific surface area was
22.1 m(2)/g, which represented a significant gain compared to the BA
(4.6 m(2)/g) due to the formation of micropores and mesopores. The
converted BA demonstrated promising performance for application as a
sorbent towards several heavy metals (oxyanions of As(V), and Cd2+,
Co2+, Ni2+, Pb2+, and Zn2+). Its performance was found to be generally
superior to that of a mainly clinoptilolite natural zeolite, achieving
greater sorption extents and better stabilizing capability of
contaminated sediments. At a lower dosage rate (50 mg sorbent per gram
sediment) to that of natural zeolite, converted BA achieved greater than
80% reduction of cationic heavy metal concentrations in sediment
porewater. These results suggest a promising route for reutilization of
MSWI-BA, which can greatly enhance the sustainability of waste
incineration technology. (C) 2011 Elsevier B.V. All rights reserved.
RI Santos, Rafael/G-1657-2011; Chiang, Yi Wai/K-5452-2012
OI Santos, Rafael/0000-0002-8368-8618;
TC 2
ZB 1
Z8 0
ZS 0
Z9 2
SN 0920-5861
UT WOS:000306358100004
ER
PT J
AU Bayat, Maryam
Sohrabi, Morteza
Royaee, Sayed Javid
TI Degradation of phenol by heterogeneous Fenton reaction using
Fe/clinoptilolite
SO JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
VL 18
IS 3
BP 957
EP 962
DI 10.1016/j.jiec.2011.09.004
PD MAY 25 2012
PY 2012
AB novel heterogeneous catalyst for degradation of phenol has been
synthesized. Dispersed metallic clusters of iron loaded on to
clinoptilolite by impregnation method. Clinoptilolite belongs to the
broad family of natural zeolites. The influences of pH, the mass ratio
of iron to clinoptilolite, the ratio of hydrogen peroxide to phenol and
catalyst loading on phenol degradation were investigated. An
autocatalytic heterogeneous-homogeneous kinetic model was proposed for
this reaction. Experiments were performed, using a stirred batch reactor
under mild conditions with 100 mg L-1 initial phenol concentration
applying Fe/clinoptilolite as a catalyst and H2O2 as an oxidant. This
new heterogeneous Fenton-like system resulted in a nearly total
elimination of phenol and 70% COD removal during 30 min. In order to
examine the effect of run time on the activity and stability of the
catalyst, the degradation reaction was carried out applying a continuous
packed bed reactor. It was observed that during 30 h time on stream no
change in the activity of the catalyst or any structural deformation of
the particles was occurred. A negligible release of iron from the
catalyst during the reaction (6 ppm) may be related to the appropriate
stability of the latter. (C) 2012 The Korean Society of Industrial and
Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
TC 3
ZB 1
Z8 0
ZS 0
Z9 3
SN 1226-086X
UT WOS:000302664500014
ER
PT J
AU Akgul, Murat
TI Effect of the activation temperature on the catalytic activity of
clinoptilolite for the benzoylation of biphenyl
SO REACTION KINETICS MECHANISMS AND CATALYSIS
VL 105
IS 2
BP 413
EP 427
DI 10.1007/s11144-011-0386-0
PD APR 2012
PY 2012
AB The Friedel-Crafts benzoylation of biphenyl (BP) was carried out under
liquid-phase batch conditions using raw and modified clinoptilolite
zeolites as catalysts. Solventless benzoylation of BP with benzoyl
chloride preferentially gave p-monoacylated product,
4-phenyl-benzophenone (4-PBP), as the main product for all catalysts
used and only small amount of diacylated product, 4,4'-dibenzoylbiphenyl
(4,4'-DBBP) was observed. The highest yield of 4-PBP was achieved by
using HT-823 zeolite as catalyst. Calcined zeolites, except the
clinoptilolite calcined at 1,023 K, are more active than their raw
counterparts. Raw clinoptilolite gave 4-PBP yield of 48.5% while the
HT-823 proves to be a highly efficient catalyst giving a very high
selectivity to 4-PBP (similar to 98.5%) with the conversion of BP
similar to 86.9% at 453 K. The results revealed that zeolite HT-823 is
the best catalyst for the benzoylation of biphenyl to 4-PBP. Also,
increasing the reaction temperature appeared to play a significant role
on the 4-PBP yield.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1878-5190
UT WOS:000303536800017
ER
PT J
AU Azar, Reihaneh Pashmineh
Falamaki, Cavus
TI Removal of aqueous Fe2+ using MnO2-clinoptilolite in a batch slurry
reactor: Catalyst synthesis, characterization and modeling of catalytic
behavior
SO JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
VL 18
IS 2
BP 737
EP 743
DI 10.1016/j.jiec.2011.11.112
PD MAR 25 2012
PY 2012
AB An Iranian clinoptilolite has been modified with MnO2 for the catalytic
removal of Fe2+ cations from water in a batch slurry reactor. The
modified zeolite was subjected to FESEM, XRD, WDX, XRF and specific
surface area analysis. A correlation for the intrinsic catalytic
reaction rate incorporating both Fe2+ and dissolved oxygen concentration
as a function of reaction temperature has been presented. The effect of
the modified zeolite aggregate particle size on the iron removal
kinetics has been investigated. It was shown that for particles larger
than 150 mu m, diffusion through the mesopores of the zeolite aggregate
is rate controlling. The effective diffusion coefficient through the
particles at RT has been calculated as 2.3 x 10(-6) cm(2) s(-1). It is
shown that liquid phase molecular diffusion within the mesopores is the
dominating mass transfer mechanism. (C) 2011 The Korean Society of
Industrial and Engineering Chemistry. Published by Elsevier B.V. All
rights reserved.
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 1226-086X
UT WOS:000301274200029
ER
PT J
AU Orha, Corina
Pop, Aniela
Lazau, Carmen
Grozescu, Loan
Tiponut, Virgil
Manea, Florica
TI SILVER DOPED NATURAL AND SYNTHETIC ZEOLITES FOR REMOVAL OF HUMIC ACID
FROM WATER
SO ENVIRONMENTAL ENGINEERING AND MANAGEMENT JOURNAL
VL 11
IS 3
BP 641
EP 649
PD MAR 2012
PY 2012
AB The purpose of the present work was to study comparatively the sorption
of humic acids from water on Ag doped natural and synthetic zeolite
envisaging the advanced drinking water treatment. Synthetic zeolite ZA
nanoparticles were synthesized from natural clinoptilolite as Si source
and sodium aluminate as Al source. The silver doped natural and
synthetic zeolites were characterized by instrumental analysis methods,
i.e., X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX)
and FTIR spectroscopy. The equilibrium adsorption studies for humic acid
allowed to assess the sorption capacity of the each zeolite, described
by the adsorption isotherms, which informs about the surface properties
and affinity of the material for the investigated pollutant. Langmuir,
Freundlich and Dubinin-Radushkevich (D-R) adsorption isotherms were used
to determine the equilibrium constants for the adsorption of the humic
acid on the zeolite for various conditions, e.g., humic acid
concentrations and zeolite amount. Also, adsorption kinetics has been
studied in terms of pseudo-first-order and pseudo-second-order to
elucidate some sorption mechanistic aspects. All determined equilibrium
and kinetic parameters showed that silver doped synthetic zeolite
exhibited better adsorptive affinity and capacity for humic acid removal
from aqueous solutions, in comparison with the silver doped natural
zeolite.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1582-9596
UT WOS:000304498900023
ER
PT J
AU Wang, Cheng
Shi, Huisheng
Li, Yan
TI Synthesis and characterization of natural zeolite supported Cr-doped
TiO2 photocatalysts
SO APPLIED SURFACE SCIENCE
VL 258
IS 10
BP 4328
EP 4333
DI 10.1016/j.apsusc.2011.12.108
PD MAR 1 2012
PY 2012
AB Natural zeolite supported Cr-doped TiO2 photocatalysts were synthesized
for the sake of improving the recovery and photocatalytic efficiency of
TiO2. The materials were characterized by X-ray diffraction (XRD),
Brunauer-Emmett-Teller (BET) surface areas, Fourier transform infrared
spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray
photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflection
spectroscopy (UV-vis DRS) and photoluminescence (PL). The photocatalytic
activity was evaluated by the degradation of methyl orange in aqueous
solution. The results show that the Cr concentration and the calcination
temperature play important role on the microstructure and photocatalytic
activity of the samples. The 10 mol% Cr-doped TiO2/zeolite calcined at
400 degrees C exhibits higher photocatalytic activity than that of the
other samples. (C) 2011 Elsevier B.V. All rights reserved.
TC 2
ZB 0
Z8 0
ZS 0
Z9 2
SN 0169-4332
UT WOS:000300991400018
ER
PT S
AU Lesnicenoks, P.
Sivars, A.
Grinberga, L.
Kleperis, J.
GP IOP
TI Hydrogen Adsorption in Zeolite Studied with Sievert and
Thermogravimetric Methods
SO INTERNATIONAL CONFERENCE ON FUNCTIONAL MATERIALS AND NANOTECHNOLOGIES
(FM&NT2012)
SE IOP Conference Series-Materials Science and Engineering
VL 38
AR 012060
DI 10.1088/1757-899X/38/1/012060
PD 2012
PY 2012
AB Natural clinoptilolite (mixture from clinoptilolite, quartz and
muscovite) is activated with palladium and tested for hydrogen
adsorption capability at temperatures RT - 200 degrees C.
Thermogravimetric and volumetric methods showed that zeolite activated
with palladium (1.25% wt) shows markedly high hydrogen adsorption
capacity - up to 3 wt%. Lower amount of adsorbed hydrogen (similar to
1.5 wt%) was found for raw zeolite and activated with higher amount of
palladium sample. Hypothesis is proposed that the heating of zeolite in
argon atmosphere forms and activates the pore structure in zeolite
material, where hydrogen encapsulation (trapping) is believed to occur
when cooling down to room temperature. An effect of catalyst (Pd) on
hydrogen sorption capability is explained by spillover phenomena were
less-porous fractions of natural clinoptilolite sample (quartz and
muscovite) are involved.
CT International Conference on Functional Materials and Nanotechnologies
(FMandNT)
CY APR 17-20, 2012
CL Univ Latvia, Inst Solild State Phys (ISSP UL), Riga, LATVIA
HO Univ Latvia, Inst Solild State Phys (ISSP UL)
SP Mat Sci & Informat Technol Latvia, Natl Res Programme
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1757-8981
BN *****************
UT WOS:000309665200060
ER
PT J
AU Emiroglu, A. O.
Eldogan, O.
Teker, M.
Keskin, A.
Ekmekci, I.
TI Catalytic reduction of NOx on vanadium exchanged natural zeolite using
microwave irradiation
SO INTERNATIONAL JOURNAL OF VEHICLE DESIGN
VL 59
IS 2-3
BP 212
EP 222
DI 10.1504/IJVD.2012.048700
PD 2012
PY 2012
AB Zeolite-based catalysts are used commonly to control NOx emissions in
selective catalytic reduction applications in lean combustion gasoline
engines. In this study, a catalyst was prepared by ion-exchange of
vanadium promoted using microwave irradiation, over the clinoptilolite
type of natural zeolite to selectively reduce the nitrogen oxides,
especially in lean combustion conditions with the HCs in the exhaust
gas. According to experimental results, the maximum NOx conversion
efficiency reached 28 % at temperature of 287 degrees C and space
velocity of 30,000 h(-1).
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 0143-3369
UT WOS:000308586000007
ER
PT J
AU Vassilev, Sasho
Genov, Krassimir
Blaskov, Vladimir
Shipochka, Maria
Boevski, Ivaylo
Stambolova, Irina
TI PREPARATION OF SUPPORTED COPPER CATALYST BY SPRAY PYROLYSIS OF COPPER
ACETATE ON HEU ZEOLITE
SO COMPTES RENDUS DE L ACADEMIE BULGARE DES SCIENCES
VL 65
IS 1
BP 41
EP 48
PD 2012
PY 2012
AB Bulgarian natural clinoptilolite was coated with copper and its oxides
via spray pyrolysis method. D.C. arc-AES method revealed the presence of
copper atoms. XRD patterns showed that after loading the Heulandite-type
(HEU-type) structure is preserved. It is also proved that several copper
phases exist on the zeolite: Cu, CuO and Cu2O. The chemical content of
natural and coated zeolite forms has been proved by XPS analysis.
Scanning Electron Microscopy (SEM) revealed Cu nanoparticles situated
over the zeolite surface as agglomerates. The ozone conversion on the
copper supported catalyst reaches 87% and does not change with the
course of time.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1310-1331
UT WOS:000300855100006
ER
PT J
AU Keskin, Ahmet
Ekmekci, Ismail
Kolip, Ahmet
TI The use of clinoptilolite as a catalyst in the gasoline engines
SO ENERGY EDUCATION SCIENCE AND TECHNOLOGY PART A-ENERGY SCIENCE AND
RESEARCH
VL 28
IS 2
BP 535
EP 544
PD JAN 2012
PY 2012
AB Practical aplication of lean burn gasoline engines on cars has been
increasing in recent years. The lean burn gasoline engine is operated
under high air/fuel ratio to improve fuel economy. However reduction of
emissions from the exhaust under oxygen rich condition is very difficult
to achieve. For this purpose, the studies on zeolite catalysts are
increasing. In this study, natural zeolite of clinoptilolite type was
prepared for use as a catalyst in gasoline engines. 9245 ppm (about
0.93%) copper were deposited on zeolite by various chemical treatments.
Ion-exchanged zeolite catalyst was tested at an SI engine. Maximum
carbonmonoxide conversion efficiency achieved was 39.5% at 2300 rpm.
Maximum hydrocarbon conversion efficiency achieved was 31.5% at 1500
rpm.
TC 3
ZB 0
Z8 0
ZS 0
Z9 3
SN 1308-772X
UT WOS:000297087600003
ER
PT J
AU Guerra, Roberto
Lima, Enrique
Viniegra, Margarita
Guzman, Ariel
Lara, Victor
TI Growth of Escherichia coli and Salmonella typhi inhibited by fractal
silver nanoparticles supported on zeolites
SO MICROPOROUS AND MESOPOROUS MATERIALS
VL 147
IS 1
BP 267
EP 273
DI 10.1016/j.micromeso.2011.06.031
PD JAN 2012
PY 2012
AB Silver nanoparticles were dispersed on clinoptilolite zeolite. These
materials were evaluated as biocides for Escherichia colt and Salmonella
typhi. Ag-zeolites were shown to be efficient in eliminating both E.
colt and S. typhi present in nutritive media. Particularly, E. colt was
eliminated at very short times. In the presence of a zeolite free of
silver, bacteria use the zeolite to reproduce rapidly. (C) 2011 Elsevier
Inc. All rights reserved.
TC 7
ZB 2
Z8 0
ZS 0
Z9 7
SN 1387-1811
UT WOS:000295906200034
ER
PT J
AU Buzetzki, Eduard
Sidorova, Katarina
Cvengrosova, Zuzana
Cvengros, Jan
TI Catalytic role of lignocellulosic materials in triacylglycerol cracking
SO JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
VL 92
IS 2
BP 314
EP 323
DI 10.1016/j.jaap.2011.07.005
PD NOV 2011
PY 2011
AB Cracking of vegetable oils and animal fats carried out with a view to
preparing fuels or fuel components for diesel engines is one of the
options of reducing high molecular weight and viscosity of natural
triacylglycerols (TAG). We have found out that lignocellulose shows a
surprisingly high catalytic activity in TAG cracking comparable and
equivalent to that achieved with zeolite catalysts NaY and
clinoptilolite. This paper presents results obtained from cracking of
rapeseed, sunflower, soybean and jatropha oils, lard and used cooking
oils in the presence of woody sawdust, cereal straw and waste paper used
as catalysts. The yield of liquid products in the feedstock was 80-90%
relative to the feedstock TAG at temperatures of 350-440 degrees C
applied for a period of 20-30 min. The yield of treated condensates
having properties similar to those of fossil diesel reached, after water
separation and evaporation of the volatile fraction up to 190 degrees C,
70-80% of the feedstock TAG. The type of the TAG and the lignocellulosic
catalyst used had no significant effect on the product yield and its
parameters. Liquid condensates obtained via catalysis with
lignocellulosic catalysts had similar composition and properties as
condensates produced by zeolite-catalyzed cracking. Blends of treated
condensates of 5-10 vol.% with fossil diesel are compliant with the EN
590 standard and can thus be used as fuels for diesel engines. (C) 2011
Elsevier B.V. All rights reserved.
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 0165-2370
UT WOS:000297386200006
ER
PT J
AU Mara, Luminita
Dima, Stefan-Ovidiu
Sarbu, Andrei
Sarbu, Liliana
Zavoianu, Rodica
Taloi, Dragos
Bacalum, Fanica
TI Obtaining of Clinoptilolitic Extrudates for Environmental Applications
II. Statistical analysis of plasticizer and shear stress effects
SO REVISTA DE CHIMIE
VL 62
IS 11
BP 1102
EP 1106
PD NOV 2011
PY 2011
AB A 2-way factorial design was used for the study of rheological
properties of clinoptilolite pastes. For all clinoptilolite samples,
studies were performed for 4 levels of plasticizer content in ceramic
mixtures and 7 levels for shear rate gamma variation, without
replicates. The analysis of variance (ANOVA) was conducted with Math CAD
software (version 14.0). Comparisons among treatments were analysed
using Fisher's least significant difference, with a significance level
alpha = 0,05.
RI Zavoianu, Rodica/B-6327-2011; Dima, Stefan-Ovidiu/C-3945-2011
OI Zavoianu, Rodica/0000-0003-1271-9955;
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0034-7752
UT WOS:000296672200012
ER
PT J
AU Lazarevic, Slavica
Jankovic-Castvan, Ivona
Onjia, Antonije
Krstic, Jugoslav
Janackovic, Djordje
Petrovic, Rada
TI Surface Characterization of Iron-Modified Sepiolite by Inverse Gas
Chromatography
SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
VL 50
IS 20
BP 11467
EP 11475
DI 10.1021/ie200595n
PD OCT 19 2011
PY 2011
AB Inverse gas chromatography at infinite and finite surface coverages was
applied to evaluate the surface properties of an iron-modified sepiolite
sorbent, Fe-sepiolite. The adsorptions of different nonpolar and polar
probes were measured in the infinite-dilution regime, in the temperature
range 483-513 K. For the organic probes used, the thermodynamic
parameters (free energy, enthalpy, and entropy) of adsorption and the
dispersive and specific components of the free energy of adsorption were
determined and are discussed in terms of specific reactions that can
occur on the adsorbent surface. Following the approach of Gutmann (The
Donor Acceptor Approach to Molecular Interactions; Plenum Press: New
York, 1978), acid/base surface characteristics were determined. The
adsorption isotherms of n-hexane, benzene, chloroform, and
tetrahydrofuran were used to estimate the specific surface areas,
isosteric heats of adsorption, and adsorption energy distributions for
the adsorption of organic molecules.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0888-5885
UT WOS:000295667100002
ER
PT J
AU Buzetzki, Eduard
Sidorova, Katarina
Cvengrosova, Zuzana
Cvengros, Jan
TI Effects of oil type on products obtained by cracking of oils and fats
SO FUEL PROCESSING TECHNOLOGY
VL 92
IS 10
BP 2041
EP 2047
DI 10.1016/j.fuproc.2011.06.005
PD OCT 2011
PY 2011
AB This paper deals with cracking of vegetable oils and animals fats in the
presence of zeolite catalysts, the objective being preparation of liquid
products similar in their properties to fossil diesel. The effects of
oil/fat type on the liquid condensate yields and parameters were
monitored. The tests were carried out with rapeseed, sunflower, soybean
and jatropha oils as well as with used frying oils. Liquid condensates
with yields of 85 to 90% relative to the input oil were obtained at
temperatures of 350 to 440 degrees C applied for the period of 20 to 30
min in the presence of zeolite catalysts NaY and clinoptilolite. The
input oil types had no significant effect on the yields and
characteristics of the treated condensate. In this respect, used frying
oils (UFO) as a feed material match other types of fresh oils and fats.
Treated condensates blended with fossil diesel (5-7% of the condensate
by volume) are compliant with the EN 590 standard and can thus be used
as a component of diesel fuels. (C) 2011 Elsevier B.V. All rights
reserved.
TC 8
ZB 0
Z8 0
ZS 1
Z9 8
SN 0378-3820
UT WOS:000293932600032
ER
PT J
AU Shakhtakhtinskii, T. N.
Yarmamedov, T. T.
Efendi, A. D.
Manafov, M. R.
Melikova, I. G.
Zaitseva, Z. A.
TI NEW HETEROGENEOUS CATALYSTS FOR DEMERCAPTANIZATION OF PETROLEUM AND
PETROLEUM PRODUCTS
SO CHEMISTRY AND TECHNOLOGY OF FUELS AND OILS
VL 47
IS 3
BP 194
EP 200
PD JUL 2011
PY 2011
AB New heterogeneous catalytic systems based on Mn-Fe- and Co-Fe-organic
cluster compounds deposited on water-free clinoptilolite which manifest
high activity in the course of demercaptanization of petroleum and
petroleum products have been developed.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0009-3092
UT WOS:000294799300006
ER
PT J
AU Nezamzadeh-Ejhieh, Alireza
Moeinirad, Solmaz
TI Heterogeneous photocatalytic degradation of furfural using
NiS-clinoptilolite zeolite
SO DESALINATION
VL 273
IS 2-3
BP 248
EP 257
DI 10.1016/j.desal.2010.12.031
PD JUN 15 2011
PY 2011
AB NiS-clinoptilolite is prepared by ion exchange and precipitation
procedures and is characterized by Fourier transformation infrared,
X-ray diffraction, thermal analysis, SEM and BET methods. The prepared
composite is used as a catalyst for photodegradation of furfural in
aqueous solution under UV irradiation. The degradation process is
monitored during the experimental runs by UV/Vis absorption, COD and TOC
concentration determination and HPLC methods. The effect of key
operating parameters such as catalyst dosage, initial concentration of
furfural, initial pH of the solutions and effect of the presence of
hydrogen peroxide and potassium bromate is studied on the degradation
efficiency. The optimal operation parameters are found as follows: pH 5,
330 mg L-1 of the catalyst loading and 6 mM of furfural concentration.
It observed that the degradation rate increased with an increasing mass
of hydrogen peroxide and potassium bromate. The NiS particles out of the
zeolite framework did not show significant degradation efficiency. (C)
2011 Elsevier B.V. All rights reserved.
TC 6
ZB 1
Z8 0
ZS 0
Z9 6
SN 0011-9164
UT WOS:000290973600002
ER
PT J
AU Kowalak, S.
Jankowska, A.
TI Natural zeolites for styrene oligomerization
SO CLAY MINERALS
VL 46
IS 2
SI SI
BP 189
EP 195
DI 10.1180/claymin.2011.046.2.189
PD JUN 2011
PY 2011
AB Hydrogen forms of natural mordenite and clinoptilolite were used as
catalysts for styrene oligomerization and as matrices to hold the
resultant oligomers in order to prepare intense and light-resistant
pigments. In contrast to synthetic zeolites of similar pore sizes
(mainly H-ZSM-5, H-mordenite), the natural zeolites did not form
products with an intense (pink) colouration. H-mordenite samples treated
with styrene developed some colour due to styrene oligomers (the
chromophore) whereas, in treated clinoptilolites, colour formation was
negligible due to the lack of access of styrene molecules into the
elliptical channels. The results of catalytic tests for cracking of
cumene (cumene and styrene have similar molecular sizes) were consistent
with the styrene oligomerization results. They indicate a noticeable
catalytic activity with natural H-mordenite and a lack of activity with
clinoptilolite. On the other hand, catalytic tests for propan-2-ol
decomposition indicate a high activity with both natural zeolites, which
confirms the presence of acid sites and their accessibility to small
alcohol molecules.
CT 8th International Conference on the Occurrence, Properties and
Utilization of Natural Zeolites
CY JUL 10-18, 2010
CL Sofia, BULGARIA
SP Inst Mineral & Crystallog; Bulgarian Acad Sci, Geolog Inst; Dept
Mineral, Petrol, Ores & Minerals; Int Nat Zeolite Assoc
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 0009-8558
UT WOS:000293257700003
ER
PT J
AU Rodriguez-Iznaga, Inocente
Petranovskii, Vitalii
Castillon-Barraza, Felipe
Concepcion-Rosabal, Beatriz
TI Copper-Silver Bimetallic System on Natural Clinoptilolite: Thermal
Reduction of Cu2+ and Ag+ Exchanged
SO JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
VL 11
IS 6
BP 5580
EP 5586
DI 10.1166/jnn.2011.3434
PD JUN 2011
PY 2011
AB Copper-silver bimetallic system supported on natural clinoptilolite from
Tasajeras deposit (Cuba) was studied. Bimetallic samples were prepared
by simultaneous ion exchange, and reduced in a wide temperature range in
a hydrogen flow. The main goal of the work was analysis of the mutual
influence of both metals on their reduction process and the properties
of the resultant particles. Analysis was done by combined use of XRD and
UV-Vis spectroscopy. The reduction of Cu2+ and Ag+ cations shows
existence of notable inter-influence between both cations during this
process. The Cu2+ reduction is favored by the presence of Ag+, which
should be related with the synergetic influence of silver cations and/or
clusters formed on the first stages of reduction on Cu2+-framework
interaction, facilitating the Cu2+ reduction even at low temperature (25
and 50 degrees C). The aggregation of the reduced highly dispersed
species both for copper and silver is limited in this bimetallic system.
The introduction of Ag+ as the second cation in the copper-exchanged
zeolites favors the copper reduction at lower temperatures (25 and 50
degrees C), and appears to be the efficient tool for the control of the
size of the resultant reduced nanoparticles (it means their dispersion).
CT 3rd International Meeting on Developments in Materials, Processes and
Applications of Emerging Technologies (MPA-2009)
CY 2009
CL Manchester, ENGLAND
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1533-4880
UT WOS:000291568100135
ER
PT J
AU Zermeno-Montante, I.
Nieto-Delgado, C.
Sagredo-Puente, R. D.
Cardenas-Galindo, M. G.
Handy, B. E.
TI Catalytic Wet Air Oxidation of Sodium Sulfide Solutions. Effect of the
Metal-Support and Acidity of the Catalysts
SO TOPICS IN CATALYSIS
VL 54
IS 8-9
BP 579
EP 586
DI 10.1007/s11244-011-9623-z
PD JUN 2011
PY 2011
AB This work evaluates the catalytic wet air oxidation of sulfide present
in spent caustic wastes generated during petroleum refining. Operating
conditions were 70 degrees C and atmospheric pressure, with and without
catalyst. Two supports (silica and clinoptilolite) and two metal oxides
(vanadium and copper) were employed to produce different catalysts. The
sulfide oxidation without catalyst displays a short induction period and
complete oxidation of sulfide at 210 min. The most active catalysts were
Cu/silica (CS) and V/clinoptilolite (VC), which improved the sulfide
oxidation, achieving complete oxidation in 20 and 26 min, respectively.
TC 2
ZB 0
Z8 0
ZS 0
Z9 2
SN 1022-5528
UT WOS:000292021100017
ER
PT J
AU Padervand, Mohsen
Tasviri, Mahboubeh
Gholami, Mohammad Reza
TI Effective photocatalytic degradation of an azo dye over nanosized
Ag/AgBr-modified TiO2 loaded on zeolite
SO CHEMICAL PAPERS
VL 65
IS 3
BP 280
EP 288
DI 10.2478/s11696-011-0013-6
PD JUN 2011
PY 2011
AB Zeolite-based photocatalysts were prepared by the sol-gel and deposition
methods. The photocatalysts were characterised by X-ray diffraction,
nitrogen adsorption-desorption isotherms, FTIR spectroscopy, scanning
electron microscopy and energy-dispersive X-ray spectrometry. The
activity of the prepared photocatalysts was evaluated by the UV-induced
degradation of acid blue 92, a textile dye in common use. The effect of
various parameters, such as catalyst concentration, initial dye
concentration, thiosulphate concentration and pH, on the rate and
efficiency of the photocatalytic degradation of acid blue 92 was
investigated. The results showed that each parameter influenced the
degradation rate and efficiency in a particular way. It was also found
that, under optimised conditions, Ag/AgBr/TiO2/zeolite exhibited the
highest photocatalytic performance. A comparison of catalytic activity
when exposed to visible light under the same conditions showed that the
photocatalysts containing AgBr had the highest activity.
TC 5
ZB 0
Z8 0
ZS 0
Z9 5
SN 0366-6352
UT WOS:000288451100004
ER
PT J
AU Atalay, Burcu
Gunduz, Gonul
TI Isomerizaton of alpha-pinene over H3PW12O40 catalysts supported on
natural zeolite
SO CHEMICAL ENGINEERING JOURNAL
VL 168
IS 3
BP 1311
EP 1318
DI 10.1016/j.cej.2011.02.037
PD APR 15 2011
PY 2011
AB The liquid phase isomerization of a-pinene over a catalyst with
12-tungstophosphoric acid (HPW) supported on natural zeolite rich in
clinoptiolite was studied in a batch slurry reactor in a nitrogen
atmosphere and at constant temperature of 373 K. The catalysts prepared
were characterized by nitrogen adsorption, XRD, SEM, and DSC
measurements. The catalytic activity increased from 15% to 99% with the
introduction of HPW at 4.25 wt% onto the natural zeolite. However, the
catalytic activity decreased with the calcination of the catalyst
sample. XRD studies indicated that only the HPW catalyst supported on
natural zeolite without calcination was the one where the HPW crystals
were formed, no significant HPW crystals were observed in the calcined
sample. The main reaction products of the isomerization reaction of
a-pinene were camphene and limonene with selectivities of about 40% and
3%, respectively, over the HPW catalyst supported on natural zeolite
without heat treatment. One and a half order dependency on a-pinene
consumption was observed and activation energy was established to be
65.4 kJ/mol. (C) 2011 Elsevier B.V. All rights reserved.
TC 7
ZB 1
Z8 2
ZS 0
Z9 9
SN 1385-8947
UT WOS:000290369200041
ER
PT J
AU Boevski, Ivailo
Genov, Krassimir
Boevska, Nina
Milenova, Katya
Batakliev, Todor
Georgiev, Vladimir
Nikolov, Penko
Sarker, Dipak K.
TI LOW TEMPERATURE OZONE DECOMPOSITION ON Cu2+, Zn2+ AND Mn2+-EXCHANGED
CLINOPTILOLITE
SO COMPTES RENDUS DE L ACADEMIE BULGARE DES SCIENCES
VL 64
IS 1
BP 33
EP 38
PD 2011
PY 2011
AB The ion-exchange process using a natural clinoptilolite zeolite with Zn,
Mn and Cu ions was evaluated. The existence of these transition metals
in the samples was detected by DC arc-AES. XRD spectra showed that after
exchanging the HEU zeolite structure was retained. These samples were
tested as potential catalysts for ozone decomposition at ambient
temperature. A Zn-containing form was not active, whereas a Cu-exchanged
sample showed about 15% conversion and Mn-loaded zeolite showed about
32% conversion at the beginning of ozonation. Deactivation of all
investigated samples was observed.
TC 3
ZB 2
Z8 0
ZS 0
Z9 3
SN 1310-1331
UT WOS:000287943300004
ER
PT J
AU Schick, Joachim
Daou, T. Jean
Caullet, Philippe
Paillaud, Jean-Louis
Patarin, Joel
Mangold-Callarec, Claire
TI Surfactant-modified MFI nanosheets: a high capacity anion-exchanger
SO CHEMICAL COMMUNICATIONS
VL 47
IS 3
BP 902
EP 904
DI 10.1039/c0cc03604h
PD 2011
PY 2011
AB Surfactant-Modified MFI-Zeolite Nanosheets (SMZN) were used for the
first time as anion-exchangers, in the case of nitrate ion removal. The
SMZN material is characterized by high anionic exchange capacity and
removal efficiency compared to classical SMZ prepared from
clinoptilolite. The SMZN material is easily regenerated and could be
probably employed to remove other anionic pollutants.
TC 6
ZB 0
Z8 0
ZS 0
Z9 6
SN 1359-7345
UT WOS:000285515200014
ER
PT J
AU Pandova, Iveta
Panda, Anton
Jurko, Jozef
TI Clinoptilolite Testing as Sorbent Nitrogen Oxides from Combustion
Engines Gases
SO CHEMICKE LISTY
VL 105
SI SI
BP S609
EP S611
SU 4
PD 2011
PY 2011
AB By scientific knowledges published at world, the zeolities are crystalic
matters with the porous structure usable at combustion engines noxious
gases cleaning. The possibilities of natural and chemically modified
zeolite - clinoptilolite type to reduce the nitrogen oxides
concentration at noxious gases of the combustion engines were studied.
At publication are implicited the resultes of the nitrogen oxides
measurements at noxious gases obtained by testing of the filter-sorption
equipment installer on exhaust stroke.
CT 8th International Scientific - Technical Conference of Material
Engineering Practice
CY MAY 04-06, 2011
CL Herlany, SLOVAKIA
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0009-2770
UT WOS:000308673300063
ER
PT J
AU Ertas, Murat
Alma, Mehmet Hakki
TI Slow pyrolysis of chinaberry (Melia azedarach L.) seeds: Part I. The
influence of pyrolysis parameters on the product yields
SO ENERGY EDUCATION SCIENCE AND TECHNOLOGY PART A-ENERGY SCIENCE AND
RESEARCH
VL 26
IS 2
BP 143
EP 154
PD JAN 2011
PY 2011
AB In this work, the pyrolysis of chinaberry (Melia azedarach L.) seeds was
conducted under different pyrolysis temperatures (350-600 degrees C),
particle sizes (1.60-0.250 mm) and sweep gas flow rates (50-400 mL
min(-1)) in a fixed-bed reactor with heating rate of 10 degrees C
min(-1), and the optimum pyrolysis conditions were determined. The
maximum bio-oil yield of 23.38 wt.% was obtained at a pyrolysis
temperature of 500 degrees C by using a sweep gas (N(2)) flow rate of
100 mL min(-1) with a particle size range of 0.420-0.850 mm. In
addition, the chinaberry seeds with two selected catalysts, natural
zeolite (clinoptilolite) and alumina were pyrolyzed in a fixed-bed
reactor under the determined optimum pyrolysis conditions. The influence
of catalysts and their ratio (10%, 20%, 30%, 40% and 50% w/w) on the
pyrolysis conversion and product yields were investigated in detail. The
results showed that the pyrolysis temperature, sweep gas flow rate and
catalyst played more important role than the particle size on the yields
of the pyrolysis products.
TC 33
ZB 0
Z8 0
ZS 0
Z9 33
SN 1308-772X
UT WOS:000278087700005
ER
PT J
AU Nikolov, Penko
Genov, Krassimir
Konova, Petya
Milenova, Katya
Batakliev, Todor
Georgiev, Vladimir
Kumar, Narendra
Sarker, Dipak K.
Pishev, Dimitar
Rakovsky, Slavcho
TI Ozone decomposition on Ag/SiO2 and Ag/clinoptilolite catalysts at
ambient temperature
SO JOURNAL OF HAZARDOUS MATERIALS
VL 184
IS 1-3
BP 16
EP 19
DI 10.1016/j.jhazmat.2010.07.056
PD DEC 15 2010
PY 2010
AB Silver modified zeolite (Bulgarian natural clinoptilolite) and Ag/silica
catalysts were synthesized by ion exchange and incipient wet
impregnation method respectively and characterized by different
techniques. DC arc-AES was used for Ag detection. XRD spectra show that
Ag is loaded over the surface of the SiO2 sample and that after the
ion-exchange process the HEU type structure of clinoptilolite is
retained. UV-VIS (specific reflection at 310 nm) and IR (band at 695
cm(-1)) spectroscopy analysis proved that silver is loaded as a T-atom
into zeolite channels as Ag+, instead of Ha(+), Ca2+, or K+ ions,
existing in the natural clinoptilolite form. The samples Ag/SiO2 and
Ag-clinoptilolite were tested as catalysts for decomposition of gas
phase ozone. Very high catalytic activity (up to 99%) was observed and
at the same time the catalysts remained active over time at room
temperature. (c) 2010 Elsevier B.V. All rights reserved.
TC 4
ZB 2
Z8 0
ZS 0
Z9 4
SN 0304-3894
UT WOS:000284504800003
ER
PT J
AU Simakova, I. L.
Solkina, Yu. S.
Moroz, B. L.
Simakova, O. A.
Reshetnikov, S. I.
Prosvirin, I. P.
Bukhtiyarov, V. I.
Parmon, V. N.
Murzin, D. Yu.
TI Selective vapour-phase alpha-pinene isomerization to camphene over
gold-on-alumina catalyst
SO APPLIED CATALYSIS A-GENERAL
VL 385
IS 1-2
BP 136
EP 143
DI 10.1016/j.apcata.2010.07.002
PD SEP 15 2010
PY 2010
AB The vapour-phase isomerization of alpha-pinene for the first time was
studied over a supported Au catalyst. alpha-pinene was isomerized to
camphene over the 2.2% Au/gamma-Al2O3 catalyst at 463-483 K using a
solution of the reagent in n-octane as the initial reaction mixture and
H-2 or N-2 as a carrier gas. Under these conditions, the selectivity to
camphene reaches 60-80% at 99.9% conversion of a-pinene. The reaction is
found to be first-order with respect to alpha-pinene, the apparent
activation energy being similar to that observed with the conventional
TiO2 catalyst. The prominent catalyst deactivation has been observed at
increased alpha-pinene concentrations in the inlet reaction mixture (>=
4 vol% in n-octane solution). According to HRTEM and TPO results, the
deactivated catalyst contains the carbonaceous deposits that may block
the catalyst surface. Almost complete regeneration was done in flowing
O-2 at temperature up to 923 K required to totally eliminate the coke
deposits. (c) 2010 Elsevier B.V. All rights reserved.
RI Parmon, Valentin/E-8639-2012; Simakova, Irina/B-5715-2013; Murzin, Dmitry/I-6285-2013; Bukhtiyarov, Valerii/E-9487-2012
OI Parmon, Valentin/0000-0002-8877-7388; Simakova,
Irina/0000-0002-5138-4847; Murzin, Dmitry/0000-0003-0788-2643;
TC 2
ZB 1
Z8 1
ZS 0
Z9 3
SN 0926-860X
UT WOS:000281991000016
ER
PT J
AU Sfirloaga, P.
Novaconi, S.
Lazau, C.
Ratiu, C.
Orha, C.
Grozescu, I.
Vaszilcsin, N.
TI Preparation and characterization of Ag doped TiO2 incorporated in
natural zeolite
SO JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS
VL 12
IS 9
BP 1884
EP 1888
PD SEP 2010
PY 2010
AB The hybrid materials based on natural zeolite and undoped and Ag-doped
TiO2, i.e., Z-TiO2, Z-TiO2-Ag-2 and Z-TiO2-Ag-3, were successfully
synthesized by solid state reaction in ethanol solution. Undoped TiO2
and Ag-doped TiO2 nanocrystals were previously synthesized by sol-gel
method. The surface characterization of undoped TiO2 / Ag-doped TiO2 and
natural zeolite hybrid materials has been investigated by X-ray
diffraction, FT-IR spectroscopy, SEM microscopy and EDX analysis. The
results indicated that anatase TiO2 is the dominant crystalline type as
spherical form onto zeolitic matrix. The presence of Ag into hybrid
materials was confirmed by EDX analysis. Also the XRD results revealed
that the natural zeolite used is mostly clinoptilolite.
RI Sfirloaga, Paula/B-9653-2012; vaszilcsin, nicolae/J-8858-2013
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 1454-4164
UT WOS:000283514700008
ER
PT J
AU Soylu, Guelin S. Pozan
Ozcelik, Zeynep
Boz, Ismail
TI Total oxidation of toluene over metal oxides supported on a natural
clinoptilolite-type zeolite
SO CHEMICAL ENGINEERING JOURNAL
VL 162
IS 1
BP 380
EP 387
DI 10.1016/j.cej.2010.05.020
PD AUG 1 2010
PY 2010
AB Some selected (Mn(2+), Co(2+), Fe(3+), Cu(2+)) oxides supported on
clinoptilolite were tested in the catalytic incineration of toluene.
Manganese oxide on clinoptilolite was found to be the most active and
durable of all tested. The effects of ion exchanger concentration, ion
exchange time, ion exchange temperature and the type of ion exchanger
were also studied to screen metal oxide catalysts. The catalysts were
prepared by incipient wetness impregnation of clinoptilolite in hydrogen
form (HCLT). They were characterized by X-ray diffraction (XRD),
scanning electron microscopy (SEM), temperature-programmed
reduction/oxidation (TPR/TPO) and diffuse reflectance Fourier transform
infrared (DRIFT) spectroscopy techniques. Activities of the candidate
catalysts were correlated with crystallinity, surface acidity,
adsorption properties and morphological parameters. 9.5% MnO(2) on
clinoptilolite exhibits the highest performance among the different
oxides. Its higher activity was attributed to its ability to maintain
its redox potential. Furthermore, this novel generation of catalysts
appeared as active as conventional ZSM-5 and BETA. Finally, it was found
that all four metal oxides supported on clinoptilolite led to the
considerable decrease in combustion temperature. (C) 2010 Elsevier B.V.
All rights reserved.
TC 7
ZB 1
Z8 1
ZS 0
Z9 8
SN 1385-8947
UT WOS:000280625500047
ER
PT J
AU Akgul, Murat
Karabakan, Abdulkerim
TI Selective synthesis of monoolein with clinoptilolite
SO MICROPOROUS AND MESOPOROUS MATERIALS
VL 131
IS 1-3
BP 238
EP 244
DI 10.1016/j.micromeso.2009.12.029
PD JUN 2010
PY 2010
AB Raw and modified forms of clinoptilolite were used as catalyst to test
their activities in the esterification of glycerol with oleic acid.
Several chemical treatments were conducted to obtain a suitable catalyst
for the selective formation of monoester while suppressing the formation
of di- and tri-esters. Raw clinoptilolite was modified to obtain
modified clinoptilolites with various Si/Al ratio by two different
methods; passivation with tetraethylorthosilicate (TEOS) and
dealumination with HCl which both increase the Si/Al ratio. Catalysts
were characterized by X-ray diffraction (XRD), Fourier
transform-infrared (FT-IR), X-ray photoelectron (XPS) spectroscopy,
thermogravimetric/differential thermal analysis (TG/DTA), and N(2) gas
adsorption-desorption techniques. The results of the catalytic tests
indicate that clinoptilolite can catalyze the esterification of glycerol
with oleic acid efficiently. The highest acid conversion and selectivity
to monoolein were obtained in the case of the acid treated
clinoptilolite. This catalyst proves to be a highly efficient catalyst
giving a very high selectivity to monoolein similar to 63% with the
conversion of oleic acid similar to 80% at 443 K. (C) 2009 Elsevier Inc.
All rights reserved.
TC 6
ZB 1
Z8 0
ZS 0
Z9 6
SN 1387-1811
UT WOS:000276627600031
ER
PT J
AU Yao Guo-Xin
Shi Bin-Bin
Li Guo-Hua
Zheng Yi-Fan
TI Preparation and Electrocatalytic Activity of Tungsten Carbide and
Zeolite Nanocomposite
SO ACTA PHYSICO-CHIMICA SINICA
VL 26
IS 5
BP 1317
EP 1322
PD MAY 2010
PY 2010
AB WC zeolite nanocomposite was synthesized by combining a mechano-chemical
approach with the reduction. carbonization technique. We used natural
zeolite as a support and ammonia metatungsten as a tungsten source. The
pretreated zeolite was mixed with ammonia metatungsten at a
n(Si):n(W)=2:1 by a ball miller to produce the WO(3)/zeolite precursor.
The precursor was then reduced and carbonized in a CH(4)/H(2) atmosphere
at 1173 K in a furnace for a specific period of time. The product was
characterized by X. ray diffraction (XRD), scanning electron
microscopy(SEM), and X-ray energy diffusive spectroscopy (EDS). Results
showed that the sample was composed of monotungsten carbide, bitungsten
carbide, quartz, mordenite, and clinoptilolite. The diameter of the
monotungsten carbide particles was found to be about 30 nm and that of
bitungsten carbide about 20 nm. The electrocatalytic activity of the
sample for p. nitrophenol in a neutral solution was measured using a
powder microelectrode. Results show that the sample is
electrocatalytically active in a neutral p. nitrophenol solution. The
electrocatalytic activity of these samples is better than that of
mesoporous tungsten carbide and this is due to the mass fraction of WC
and the ratio of w(WC)/w(W(2)C). These results indicate that a
synergistic effect exists between the tungsten carbide and the zeolite.
TC 3
ZB 0
Z8 3
ZS 0
Z9 3
SN 1000-6818
UT WOS:000277881600022
ER
PT J
AU Dumitriu, Emil
Cobzaru, Claudia
Hulea, Vasile
Oprea, Spiridon
TI Dealuminated Natural Zeolites for Applications in Catalytic Processes
with Formation of C-C Bonds II. Aldol condensation over natural
clinoptilolite modified by dealumination
SO REVISTA DE CHIMIE
VL 61
IS 4
BP 400
EP 403
PD APR 2010
PY 2010
AB The vapor-phase aldol condensation of acetaldehyde and formaldehyde over
the natural volcanic tuff, dealuminated by acidic treatment, was
studied. The condensation reactions were performed over a temperature
range from 250 degrees to 400 degrees C. The catalytic properties were
analyzed taking into account both, the influence of the reaction
temperature and the effect of the acidic treatment applied to the
natural volcanic tuff.
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 0034-7752
UT WOS:000278425100016
ER
PT J
AU Dragoi, B.
Rakic, V.
Dumitriu, E.
Auroux, A.
TI Adsorption of organic pollutants over microporous solids investigated by
microcalorimetry techniques
SO JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
VL 99
IS 3
BP 733
EP 740
DI 10.1007/s10973-009-0353-4
PD MAR 2010
PY 2010
AB This work is focused on the gas and liquid-phase adsorption of
pollutants: propanol, 2-butanone, phenol and nicotine onto zeolites
(H-BETA, H-ZSM-5, H-MCM-22, and clinoptilolite). Textural properties and
origin of zeolites were taken into account as criteria of adsorbents
selection. The aldehyde and the ketone were adsorbed in the gas phase
using microcalorimetry linked to a volumetric line to evaluate
adsorption. Adsorptions in water were carried out for phenol and
nicotine and the evolved heats during adsorption were measured by a
differential heat flow reaction calorimeter with stirring. Results are
discussed in relation with the pore sizes and various interactions which
could occur between the adsorbent and the adsorbate.
CT 9th Mediterranean Conference on Calorimetry and Thermal Analysis
CY JUN 15-18, 2009
CL Marseille, FRANCE
RI Dragoi, Brindusa/A-8142-2012
TC 11
ZB 2
Z8 0
ZS 0
Z9 11
SN 1388-6150
UT WOS:000275657800003
ER
PT J
AU Tomaszewska, Karina
Kaluzna-Czaplinska, Joanna
Jozwiak, Wojciech
TI Thermo-catalytic degradation of low density polyethylene over
clinoptilolite - the effect of carbon residue deposition
SO POLIMERY
VL 55
IS 3
BP 222
EP 226
PD MAR 2010
PY 2010
AB Thermo-catalytic degradation of low density polyethylene (PE-LD) was
studied in the presence of the natural zeolite - clinoptilolite. The
effect of carbon deposition on the catalyst activity was also
investigated. It was observed that the PE-LD degradation process over
clinoptilolite proceeded at shorter time and lower temperature. The
catalyst activity tests were carried out in argon in a stainless steel
batch reactor at temperature, up to 410 degrees C at ambient pressure.
The decomposition products were classified into three groups: gases,
liquids and solid-like residues. The liquid products were analysed by
gas chromatography coupled with mass spectrometry GC/MS method. A shift
towards lower molecular mass products was observed in reactions with
fresh clinoptilolite. The application of this catalyst in thermal
degradation of PE-LD leads to lower alkane to alkene ratios and inhibits
the formation of cyclohydrocarbons. The presence of carbon deposit on
the surface of re-used clinoptilolite leads to higher ratio of saturated
to unsaturated hydrocarbons, but neither did it significantly change
reaction temperature nor the phase composition of the reaction products.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0032-2725
UT WOS:000275484600009
ER
PT J
AU Jose Solache-Rios, Marcos
Villalva-Coyote, Rafael
del Carmen Diaz-Nava, Maria
TI Sorption and Desorption of Remazol Yellow by a Fe-Zeolitic Tuff
SO JOURNAL OF THE MEXICAN CHEMICAL SOCIETY
VL 54
IS 1
BP 59
EP 67
PD JAN-MAR 2010
PY 2010
AB The adsorption of remazol yellow from aqueous solution was evaluated
using a Fe-zeolitic tuff. The adsorbent was characterized by scanning
electron microscopy, IR spectroscopy and X-Ray diffraction. Sorption
kinetic and isotherms were determined and the adsorption behavior was
analyzed. Kinetic pseudo-second order and Langmuir-Freundlich models
were successfully applied to the experimental results, indicating
chemisorption on a heterogeneous material. The regeneration of the
material was best accomplished by using a H(2)O(2) solution. The
sorption capacity of the Fe-zeolitic tuff increased when the saturated
samples were treated with a H(2)O(2) or FeCl(3) solution.
TC 2
ZB 1
Z8 0
ZS 0
Z9 2
SN 1870-249X
UT WOS:000280769300010
ER
PT B
AU Pastorkova, Katarina
Lazistan, Filip
Kadlecikova, Magdalena
Breza, Juraj
Jesenak, Karol
Kolmacka, Michal
Michalka, Miroslav
GP TANGER Ltd
TI CONNECTIONS AND BRIDGES OF CARBON NANOTUBE GROWN ON ALUMINOSILICATES
(NAMELY: MONTMORILLONITE AND ZEOLITE - CLINOPTILOLITE)
SO NANOCON 2010, 2ND INTERNATIONAL CONFERENCE
BP 385
EP 387
PD 2010
PY 2010
AB Multiwalled carbon nanotubes (MWNTs) were grown on aluminosilicates,
through anchoring on Fe nanoparticles. The starting aluminosilicates are
commercial montmorillonite and zeolite (clinoptilolite) in which the
intercalated original ions were exchanged for Fe(III) ions via
ion-exchange reactions and impregnation methods. Appropriate
aluminosilicate was immersed into an aqueous solution of Fe(III) salt
with 0.04 M concentration. The suspensions were deposited on a Si wafer
by sedimentation and allowed to dry quickly by an infrared lamp. MWNTs
were synthesized by catalytic decomposition of methane on the surface of
aluminosilicates at 600-700 degrees C by hot filament chemical vapour
deposition process. These Fe(III) loaded aluminosilicates were used as
catalysts. The nanotubes were bridging-cross both single parts of
aluminosilicates and micro-cracks which had been formed during the quick
drying of aluminosilicates. The carbon nanotubes (CNTs) formed a
three-dimensional CNTs/aluminosilicate network.
CT 2nd NANOCON International Conference
CY OCT 12-14, 2010
CL Olomouc, CZECH REPUBLIC
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
BN 978-80-87294-19-2
UT WOS:000286656400067
ER
PT J
AU Tomaszewska, Karina
Kaluzna-Czaplinska, Joanna
Jozwiak, Wojciech K.
TI Thermal and thermo-catalytic degradation of polyolefins as a simple and
efficient method of landfill clearing
SO POLISH JOURNAL OF CHEMICAL TECHNOLOGY
VL 12
IS 3
BP 50
EP 57
DI 10.2478/v10026-010-0034-x
PD 2010
PY 2010
AB Thermal degradation of the low density polyethylene (LDPE),
polypropylene (PP) and the municipal waste plastics was investigated.
The thermo-catalytic degradation of LDPE and PP was studied in the
presence of the following catalysts: four different types of
montmorillonite: K5, K10, K20, K30 and - for comparison - zeolites
(natural - clinoptilolite, Y(Na+) and Y(H+)). Thermal analyses TG-DTA-MS
of polymers and polymer-catalyst mixtures were carried out in an argon
flow atmosphere in isothermal and dynamic conditions. The following
order was found: in lowering the reaction temperature for LDPE
degradation Y(H+) > mK5 > mK20 = mK30 > mK10 > NZ > Y(Na+); for PP
degradation: mK20 > mK5 = mK30 > mK10 > Y(H+) > NZ > Y(Na+). The
activity tests were carried out in a stainless steel batch reactor under
atmospheric pressure in a wide temperature range of up to 410 degrees C,
and using the atmosphere of argon flow. The liquid products were
analysed by the GC-MS method. The hydrocarbons in the liquid products
from thermal degradation of polymers were broadly distributed in the
carbon fractions of C(8) to C(26) - for LDPE and C(6) to C(31) for PP.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1509-8117
UT WOS:000282212200013
ER
PT J
AU Farias, Tania
Rabdel Ruiz-Salvador, A.
Velazco, Lya
Charles de Menorval, Louis
Rivera, Aramis
TI Preparation of natural zeolitic supports for potential biomedical
applications
SO MATERIALS CHEMISTRY AND PHYSICS
VL 118
IS 2-3
BP 322
EP 328
DI 10.1016/j.matchemphys.2009.07.054
PD DEC 15 2009
PY 2009
AB Considering the biological properties reported for the purified natural
clinoptilolite, NZ, we prepared and Li-enriched forms aimed at release
matrices for biomedical applications. The raw material and obtained
solid samples were characterized by means of atomic absorption
spectroscopy, X-ray diffraction, 27 Al and 19Si MAS nuclear magnetic
resonance, and nitrogen adsorption. The results demonstrate the
structural stability ofthe materials after the different transformations
applied. The chemical behavior of the samples in bi-distilled water and
hydrochloric acid was studied by pH and conductivity measurements. A
preliminary study related with the liberation ofK and Li in aqueous
medium was carried out atomic absorption spectroscopy. The studies
showed that the release of both ions from the solid sample and that
lithium is released faster than potassium in both dissolution me is
favored in HCl solutions. (C) 2009 Elsevier B.V. All rights reserved.
TC 7
ZB 0
Z8 0
ZS 0
Z9 7
SN 0254-0584
UT WOS:000271892800013
ER
PT J
AU Ozcelik, Zeynep
Soylu, Guelin S. Pozan
Boz, Ismail
TI Catalytic combustion of toluene over Mn, Fe and Co-exchanged
clinoptilolite support
SO CHEMICAL ENGINEERING JOURNAL
VL 155
IS 1-2
BP 94
EP 100
DI 10.1016/j.cej.2009.07.013
PD DEC 1 2009
PY 2009
AB Catalytic combustion of toluene over Fe, Co, and Mn transition metal
oxides catalysts supported on clinoptilolite (CLT) has been
investigated. The catalysts have been characterized by X-ray diffraction
(XRD), scanning electron microscopy (SEM), temperature-programmed
reduction and oxidation (TPR/TPO) and thermogravimetric analysis (TGA).
9.5MnO(2)/NaCLT catalyst exhibited the catalytic activity, over which
the toluene conversion reached to 93% at a temperature of 350 degrees C.
The increase in activity was followed by increasing metal oxide content
and gave a optimum at 9.5% MnO(2) loading. Addition of metal oxide into
clinoptilolite support led to a measurable decrease in the onset of
combustion and an increase in toluene conversion. (C) 2009 Elsevier B.V.
All rights reserved.
TC 11
ZB 3
Z8 1
ZS 0
Z9 11
SN 1385-8947
UT WOS:000274769500012
ER
PT J
AU Kasaie, Maryam
Sohrabi, Morteza
TI Kinetic Study on Methanol Dehydration to Dimethyl Ether Applying
Clinoptilolite Zeolite as the Reaction Catalyst
SO JOURNAL OF THE MEXICAN CHEMICAL SOCIETY
VL 53
IS 4
BP 233
EP 238
PD OCT-DEC 2009
PY 2009
AB Dehydration of methanol to dimethyl ether (DME), using
clinoptilolite-zeolite as the reaction catalyst, within the temperature
range of 300-350 degrees C has been studied in a continuous fluidized
bed reactor. The reactor was a cylindrical tube, 26 mm internal diameter
and 0.5 m high, placed vertically in a furnace. The effects of some
pertinent operating parameters, such as temperature, superficial gas
velocity, catalyst's particle size, and methanol partial pressure, on
the extent of dehydration reaction have been investigated. Two
hydrodynamic models presented for bubbling fluidized bed reactors, i.
e., Kunii-Levenspiel (K-L) as an example of three phase models and
El-Halwagi-El-Rifai (H-R) as an example of compartment models were
applied to correlate the experimental data. It was determined that the
mean absolute deviation between the experimental data and those
predicted from K-L model was lower than that observed in the case of H-R
model (19% and 70%, respectively). Among the operating parameters,
partial pressure of methanol was found to have the highest impact on the
process yield.
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 1870-249X
UT WOS:000276727200005
ER
PT J
AU Meshkova, I. N.
Kudinova, O. I.
Kovaleva, N. Yu.
Grinev, V. G.
Ladygina, T. A.
Kiseleva, E. V.
Novokshonova, L. A.
TI Effect of the Zeolite Support on the Polymerization of Propylene with
Immobilized ansa-Zirconocene Catalysts
SO POLYMER SCIENCE SERIES B
VL 51
IS 9-10
BP 401
EP 408
DI 10.1134/S1560090409090127
PD OCT 2009
PY 2009
AB Anchored aluminoxanes are synthesized by the reaction of aluminum alkyls
AlMe(3) and Al(i-Bu)(3) with water contained in the intracrystalline
cavities of synthetic and natural zeolites (NaY ( Si : Al = 5), HZSM-5
(Si : Al = 17 or 34), NH(4)ZSM-5 (Si : Al = 32), NaZSM-5 ( Si : Al =
42), and clinoptilolite-containing tuff) and are used for the synthesis
of heterogenized complexes of ansa-zirconocenes
(rac-C(2)H(4)(Ind)(2)ZrCl(2), rac-Me(2)Si(Ind)(2)ZrCl(2), and
rac-[1-(9-eta(5)-Flu)-2-(5,6-cyclopenta-2-Me-1-eta(5)-Ind)C(2)H(4)]ZrCl(
2)) active in the polymerization of propylene. The nature of the zeolite
support determines the content of zeolite water and affects the
formation of anchored alkylaluminoxanes and the activity of immobilized
catalysts. Among the studied catalytic systems supported on zeolites,
NaY and NaZSM-5 are the most efficient for the polymerization of
propylene. PP synthesized with the supported zirconocene catalysts has a
higher molecular mass and a wider molecular-mass distribution than those
in the case of the corresponding homogeneous catalyst. The index of
isotacticity and the content of pentads mmmm in PP prepared with
immobilized metallocenes with the C(2) symmetry, such as
rac-C(2)H(4)(Ind)(2)ZrCl(2) and rac-Me(2)Si(Ind)(2)ZrCl(2), are likewise
higher. The stereoselectivity of supported catalysts depends on the
zeolite nature.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1560-0904
UT WOS:000271547400012
ER
PT J
AU Doula, Maria K.
TI Simultaneous removal of Cu, Mn and Zn from drinking water with the use
of clinoptilolite and its Fe-modified form
SO WATER RESEARCH
VL 43
IS 15
BP 3659
EP 3672
DI 10.1016/j.watres.2009.05.037
PD AUG 2009
PY 2009
AB Zeolites have been widely used in water treatment and especially
clinoptilolite, due to its low cost and high abundance. It has large
cation-exchange capacity and is capable of removing large quantities of
heavy metals from contaminated water samples. By loading the surface of
clinoptilolite with amorphous Fe-oxide species, a total improvement in
adsorption capacity could be achieved. Thus, the Clin-Fe oxide system is
capable of adsorbing significantly higher heavy metal concentrations
than untreated clinoptilolite with simultaneous noticeable decrease in
water hardness. Batch adsorption experiments have shown that Clin-Fe
system has very large Cu, Zn and Mn adsorption capacity and for most of
the cases the treated water samples were suitable for human consumption
or agricultural use. New experiments were conducted to study the
effectiveness of clinoptilolite and of the Clin-Fe system in removal of
Cu, Mn, Zn, present simultaneously in water samples, so that the study
of metal-sorbent chemical behavior and of the adsorption selectivity
would be feasible. Desorption of metals was also examined and an
integrated approach of the effectiveness of such materials in drinking
water treatment is presented. (C) 2009 Elsevier Ltd. All rights
reserved.
TC 23
ZB 9
Z8 3
ZS 0
Z9 26
SN 0043-1354
UT WOS:000269049300003
ER
PT J
AU Li, Fangfei
Jiang, Yinshan
Xia, Maosheng
Sun, Mengmeng
Xue, Bing
Ren, Xuehong
TI A high-stability silica-clay composite: Synthesis, characterization and
combination with TiO2 as a novel photocatalyst for Azo dye
SO JOURNAL OF HAZARDOUS MATERIALS
VL 165
IS 1-3
BP 1219
EP 1223
DI 10.1016/j.jhazmat.2008.10.001
PD JUN 15 2009
PY 2009
AB A novel micro-mesopores composite material has successfully been
synthesized at basic hydrothermal conditions using natural mineral
montmorillonite (MMT) and tetraethoxysilane (TEOS). Two surfactants,
cetyltrimethyl ammonium bromide (CTAB) and polyethylene glycol (PEG),
have been employed in order to shape the pores in the composite. The
resultant silica-clay has large surface area (472 m(2)/g) and high
hydrothermal stability, which makes it a potentially host-material for
catalyst. The molecular size of different surfactant leads to the
multi-peak distribution of pore size, and the surfactant of larger size
(PEG) corresponds to the formation of larger pores. Moreover, the
photocatalytic results show that, comparing with pure TiO2 particles,
the loaded TiO2 on such silica-clay shows higher photodegradation rate
of methyl orange (MO) in aqueous. And another porous aluminosilicate
host, zeolite, was also discussed for comparison. (c) 2008 Elsevier B.V.
All rights reserved.
TC 9
ZB 4
Z8 2
ZS 0
Z9 9
SN 0304-3894
UT WOS:000266121700165
ER
PT J
AU Heravi, M. M.
Bakhtiari, K.
Oskooie, H. A.
Hekmatshoar, R.
TI Clinoptilolite-supported iron(III) nitrate as a powerful and efficient
deoximation catalyst. Fast regeneration of carbonyl compounds from
oximes
SO RUSSIAN JOURNAL OF ORGANIC CHEMISTRY
VL 45
IS 6
BP 863
EP 864
DI 10.1134/S1070428009060104
PD JUN 2009
PY 2009
AB Clinoptilolite-supported iron(III) nitrate (clinofen) ensures fast and
efficient regeneration of carbonyl compounds from the corresponding
oximes.
TC 2
ZB 1
Z8 0
ZS 0
Z9 2
SN 1070-4280
UT WOS:000267898400010
ER
PT J
AU Savelieva, G. A.
Abdukhalykov, D. B.
Dossumov, K.
TI Research of the Activity of Catalysts on the Base of H(3)PW(12)O(40) in
Partial Oxidative Conversion of C(3)-C(4) alkanes
SO CATALYSIS LETTERS
VL 128
IS 1-2
BP 106
EP 110
DI 10.1007/s10562-008-9696-x
PD MAR 2009
PY 2009
AB Catalysts from heteropoly acid H(3)PW(12)O(40) and its Cs, Na, Ba, Pb,
Ca, Cd, Cr, Mn, V, La salts supported on clinoptilolite, alumosilicate
are highly active in oxidative conversion of propane-butane (OCPB)
mixture and formation of C(2)-C(4) olefins, oxygen-containing compounds
at temperatures T = 100-800 A degrees C. Optimum yields of ethylene and
propylene are achieved on heteropoly acid its Cs and Cr salts. The
processes of oxidative dehydrogenation (ODPB) and cracking are
concurrent in formation of olefins. High activity is caused by
dispersity of supported catalysts (XRD, IRS) both formation of crystal
hydrates and an amorphous phase of heteropoly acid in a condition of
interaction with the carrier.
TC 1
ZB 0
Z8 1
ZS 0
Z9 1
SN 1011-372X
UT WOS:000263070700016
ER
PT J
AU Putun, Ersan
Uzun, Basak Burcu
Putun, Ayse Eren
TI Rapid Pyrolysis of Olive Residue. 2. Effect of Catalytic Upgrading of
Pyrolysis Vapors in a Two-Stage Fixed-Bed Reactor
SO ENERGY & FUELS
VL 23
BP 2248
EP 2258
DI 10.1021/ef800978m
PD MAR-APR 2009
PY 2009
AB The upgrading of the rapid pyrolysis vapors was performed using various
catalysts (clinoptilolite (a natural zeolite, NZ), ZSM-5, H-Y) with
catalyst/feed ratios of 0.05, 0.1, 0.15, 0.20, and 0.25 in the catalyst
bed temperature range of 350-500 degrees C on the product distributions.
The catalytic treatment with synthetic zeolites provided enhancement of
the gas yields and reduction of the oil yields. Moreover, the high
catalyst/feed ratio was favored to increase of gas yields. ZSM-5 was
very effective in gas production, whereas NZ was in bio-oil production
without any severe coking, compared to synthetic zeolites. H-Y showed a
higher tendency of formation of coke and tar. Moreover, a catalyst bed
temperature of >450 degrees C caused enhancement of the gas yields and
reduction of the oil yields. After application of catalytic treatment,
the long chains of alkanes and alkenes of the pyrolysis oil were
converted to lower-weight hydrocarbons. An increase of aliphatics,
aromatics, and olefins and a sharp decrease of asphaltenes and polar
groups (highly oxygenated groups) were determined. NZ was determined to
be very effective in aliphatic production, whereas ZSM-5 produced more
aromatics. Consequently, comparing the natural zeolite with synthetics
on bio-oil production, NZ exhibited better performance.
TC 24
ZB 5
Z8 2
ZS 0
Z9 24
SN 0887-0624
UT WOS:000265439000149
ER
PT J
AU Rakitskaya, T. L.
Kiose, T. A.
Voloshchuk, A. G.
Oleksenko, L. P.
Volkova, V. Ya.
Reznik, L. I.
TI Effect exerted by acid modification of bazalt tuff on catalytic activity
of fixed acido complexes of palladium(II) and copper(II) in the reaction
of carbon(II) oxide oxidation with air oxygen
SO RUSSIAN JOURNAL OF APPLIED CHEMISTRY
VL 82
IS 2
BP 204
EP 208
DI 10.1134/S1070427209020074
PD FEB 2009
PY 2009
AB The physicochemical and structural characteristics of bazalt tuff were
studied. The optimal conditions of its acid modification, at which the
high-activity catalyst Pd(II)-Cu(II)-Br-/H-bazalt tuff of a
low-temperature oxidation of carbon(II) oxide with air oxygen is formed,
were determined.
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 1070-4272
UT WOS:000264630700006
ER
PT J
AU Yadav, Mukesh Kr.
Patil, Mallikarjun V.
Jasra, Raksh V.
TI Acetoxylation and hydration of limonene and alpha-pinene using
cation-exchanged zeolite beta
SO JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
VL 297
IS 2
BP 101
EP 109
DI 10.1016/j.molcata.2008.09.017
PD JAN 14 2009
PY 2009
AB Hydration and acetoxylation of limonene and alpha-pinene into terpineol
and terpinyl acetate in the liquid phase have been studied using
transition metal and rare earth ion-exchanged beta zeolite. These
catalysts under optimized reaction conditions showed higher activity and
selectivity compared to conventionally used acid catalysts such as
H(2)SO(4) and amberlyst-15. Conversions of 9-26% and 58-82% were
obtained for limonene the in presence of glacial and aqueous acetic
acid, respectively, and the selectivity for major products
alpha-terpinyl acetate and terpineol were up to 54% and 65%,
respectively. Conversion values in the range of 62-100% and 72-100% were
obtained for alpha-pinene in the presence of glacial and aqueous acetic
acid, respectively. Virtually no oligomerisation of monoterpenes
occurred understudied conditions. From the measured acidity data of
these zeolites, it is observed that both hydration and acetoxylation are
Bronsted acid-catalysed reactions. (C) 2008 Elsevier B.V. All rights
reserved.
TC 10
ZB 2
Z8 2
ZS 0
Z9 11
SN 1381-1169
UT WOS:000262706600006
ER
PT J
AU Nikolov, Penko
Milenova, Katya
Genov, Krassimir
Boevski, Ivailo
TI PHYSICOCHEMICAL PROPERTIES OF SILVER EXCHANGED CLINOPTILOLITE FROM BELI
PLAST, EAST RHODOPES
SO COMPTES RENDUS DE L ACADEMIE BULGARE DES SCIENCES
VL 62
IS 11
BP 1393
EP 1398
PD 2009
PY 2009
AB Bulgarian natural zeolite clinoptilolite was ion exchanged with silver.
D.C. arc-AES was used for Ag detection. XRD patterns show that after
exchanging the HEU type structure is kept. UV-VIS (specific reflection
at 310 nm) and IR (band at 695 cm(-1)) spectroscopy analysis proved that
silver is loaded as T-atom into zeolite channels as Ag(+), instead of
Na(+), Ca(2+), or K(+) ions, existing in natural form, there is only a
small amount of extra-framework Ag over zeolite matrix (reflection at
380 nm). This sample can be used further as catalyst or as antibacterial
agent. After leaching of Ag(+) from the channels (with the help of
surfactant) the silver had transformed into Ag(0) particles over the
zeolite matrix. The sample can be further regenerated again with new
silver load.
TC 2
ZB 2
Z8 0
ZS 0
Z9 2
SN 1310-1331
UT WOS:000273278300006
ER
PT J
AU Baek, Seung-Chan
Lee, Yun-Jo
Jun, Ki-Won
Hong, Suk Bong
TI Influence of Catalytic Functionalities of Zeolites on Product
Selectivities in Methanol Conversion
SO ENERGY & FUELS
VL 23
IS 1
BP 593
EP 598
DI 10.1021/ef800736n
PD JAN-FEB 2009
PY 2009
AB In an attempt to understand the textural and acidic properties of
zeolites on the methanol conversion and product selectivities, three
zeolites, ferrierite, clinoptilolite, and SAPO-34, are studied,
Temperature-programmed desorption of ammonia (NH(3)-TPD) indicated the
presence of more weak acidity on ferrierite and clinoptilolite compared
to the considerable strong acidity on SAPO-34. At 250 degrees C, all
three samples exhibited comparable methanol conversions, but relatively
lower dimethyl ether (DME) and higher light olefins are observed on
SAPO-34. Ferrierite and clinoptilolite samples exhibited high
selectivity for the formation of DME even at higher reaction
temperatures (400 degrees C), while the product shifted from DME to
light olefins with an increasing reaction temperature on SAPO-34.
Especially, ferrierite, owing to its mild acidity and small pore size,
is found to be a good catalyst for the methanol conversion to DME at 250
degrees C without significant deactivation for 100 h time on stream.
TC 6
ZB 1
Z8 1
ZS 0
Z9 7
SN 0887-0624
UT WOS:000263629900088
ER
PT J
AU Cobzaru, Claudia
Oprea, Spiridon
Dumitriu, Emil
Hulea, Vasile
TI Gas phase aldol condensation of lower aldehydes over clinoptilolite rich
natural zeolites
SO APPLIED CATALYSIS A-GENERAL
VL 351
IS 2
BP 253
EP 258
DI 10.1016/j.apcata.2008.09.024
PD DEC 30 2008
PY 2008
AB Catalytic materials prepared from natural clinoptifolite by ion exchange
and acid treatment have been successfully used in the gas phase
conversion of acetaldehyde and formaldehyde into acrolein. The
modifications made on the raw clinoptilolite have generated important
changes of the texture and catalytic sites. The results in catalysis
showed that the nature and the amount of condensation products strongly
depend on the acid-base properties of catalysts. The highest stability,
activity and selectivity to acrolein have been proved by the catalysts
having high number and strength of basic sites. (C) 2008 Elsevier B.V.
All rights reserved.
TC 6
ZB 1
Z8 0
ZS 0
Z9 6
SN 0926-860X
UT WOS:000261931600015
ER
PT J
AU Erdogan, B. C.
Seyhan, A. T.
Ocak, Y.
Tanoglu, M.
Balkose, D.
Ulku, S.
TI Cure kinetics of epoxy resin-natural zeolite composites
SO JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
VL 94
IS 3
BP 743
EP 747
DI 10.1007/s10973-008-9366-7
PD DEC 2008
PY 2008
AB The cure kinetics of epoxy resin and epoxy resin containing 10 mass% of
natural zeolite were investigated using differential scanning
calorimetry (DSC). The conformity of the cure kinetic data of epoxy and
epoxy-zeolite system was checked with the auto-catalytic cure rate
model. The results indicated that the hydroxyl group on the zeolite
surface played a significant role in the autocatalytic reaction
mechanism. This group was able to form a new transition state between
anhydride hardener and epoxide group. The natural zeolite particles
acted as catalyst for the epoxy system by promoting its curing rate.
CT 31st International Conference on Vacuum Microbalance Techniques
CY SEP 12-14, 2007
CL Izmir Inst Technol, Izmir, TURKEY
HO Izmir Inst Technol
SP Izmir Inst Technol, Engn Fac, Dept Chem Engn; Turkish Sci & Technol Res
Council; Ege Branch Chamber Chem Engineers; Ege Reg Chamber Ind;
Bausparkasse Mainz; Rubothem; Pigment A; Terra Lab; Terra A; IItek Ltd
TC 7
ZB 0
Z8 0
ZS 0
Z9 7
SN 1388-6150
UT WOS:000261832000025
ER
PT J
AU Elaiopoulos, K.
Perraki, Th.
Grigoropoulou, E.
TI Mineralogical study and porosimetry measurements of zeolites from
Scaloma area, Thrace, Greece
SO MICROPOROUS AND MESOPOROUS MATERIALS
VL 112
IS 1-3
BP 441
EP 449
DI 10.1016/j.micromeso.2007.10.021
PD JUL 1 2008
PY 2008
AB The zeolites of the Skaloma area, Thrace, Greece, were studied by
scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray
fluorescence (XRF), N-2-porosimetry and Fourier transform infrared
(FTIR) spectroscopy. Thermogravimetric analysis (TG/DTG) was also
applied. The main mineral constituent is "heulandite type-II", an
intermediate type of the isomorphous series heulandite-clinoptilolite
end members. Significant amounts of mordenite were found to contribute
to the mineral structure as a secondary zeolitic phase. Traces of
feldspars, muscovite, cristobalite and smectite were also detected. The
surface properties of the zeolitic material, as derived from the N-2
adsorption-desorption isotherms at normal boiling temperature, were
found to depend strongly on the pretreatment (degassing) conditions. (C)
2007 Elsevier Inc. All rights reserved.
TC 12
ZB 3
Z8 0
ZS 0
Z9 12
SN 1387-1811
UT WOS:000256713300049
ER
PT J
AU Kadlecikova, M.
Breza, J.
Jesenak, K.
Pastorkova, K.
Luptakova, V.
Kolmacka, M.
Vojackova, A.
Michalka, M.
Vavra, I.
Krizanova, Z.
TI The growth of carbon nanotubes on montmorillonite and zeolite
(clinoptilolite)
SO APPLIED SURFACE SCIENCE
VL 254
IS 16
BP 5073
EP 5079
DI 10.1016/j.apsusc.2008.02.005
PD JUN 15 2008
PY 2008
AB Synthesis of carbon nanotubes described in the present work is based on
activation of methane in a hot filament CVD reactor and subsequent
creation of nanostructures on a catalyst pre-treated polished surface of
silicon. An essential step of the synthesis is the use of natural
minerals as catalysts. We have studied the catalyst parameters, the way
of its application and the amount of Fe(3+) cations on the surface of
aluminosilicates on the quality of the grown nanotube layers. The growth
of carbon nanotubes catalyzed by montmorillonite and zeolite
(clinoptilolite) was confirmed by scanning electron microscopy and Raman
spectroscopy. (C) 2008 Elsevier B.V. All rights reserved.
TC 15
ZB 1
Z8 0
ZS 0
Z9 15
SN 0169-4332
UT WOS:000255728500025
ER
PT J
AU Mikulec, Jozef
Vrbova, Miriam
TI Catalytic and thermal cracking of selected polyolefins
SO CLEAN TECHNOLOGIES AND ENVIRONMENTAL POLICY
VL 10
IS 2
BP 121
EP 130
DI 10.1007/s10098-007-0132-5
PD MAY 2008
PY 2008
AB Feedstock recycling is a promising alternative for the management of
plastic wastes, as it may allow these residues to be transformed into
valuable products for refinery and/or petrochemical industry. Catalytic
degradation of polyolefin was carried out in a pilot scale reactor
Blowdec (R) operating in the temperature range of 340-470 degrees C. The
catalysts used in this study were natural zeolite Clinoptilolite, ZSM-5,
HZSM-5 and their mixture in various volume ratios. Both thermal and
catalytic cracking of low-density polyethylene (LDPE), high-density
polyethylene (HDPE), polypropylene (PP) and their mixture have been
investigated. Liquid products were checked in selected refinery and
petrochemical processes as feedstocks on the model pyrolysis equipment
and with the help of MAT test (microactivity test).
TC 7
ZB 1
Z8 0
ZS 0
Z9 7
SN 1618-954X
UT WOS:000260826100005
ER
PT J
AU Miskolczi, N.
Bartha, L.
TI Investigation of hydrocarbon fractions form waste plastic recycling by
FTIR, GC, EDXRFS and SEC techniques
SO JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS
VL 70
IS 6
BP 1247
EP 1253
DI 10.1016/j.jbbm.2007.05.005
PD APR 24 2008
PY 2008
AB Waste high-density polyethylene was converted into different hydrocarbon
fractions by thermal and then-no-catalytic batch cracking. For the
catalytic degradation of waste plastics three different catalysts
(equilibrium FCC, HZSM-5 and clinoptilolite) were used. Catalysts differ
basically in their costs and activity due to the differences of micro-
and macroporous surface areas and furthermore the Si/Al ratio and
acidities are also different. Mild pyrolysis was used at 430 degrees C
and the reaction time was 45 min in each case. The composition of
products was defined by gas chromatography, Fourier transform infrared
spectroscopy, size exclusion chromatography, energy-dispersive X-ray
fluorescence spectroscopy and other standardized methods. The effects of
catalysts on the properties of degradation products were investigated.
Both FCC and clinoptilolite catalysts had considerably catalytic
activity to produce light hydrocarbon liquids, while HZSM-5 catalyst
produced the highest amount of gaseous products. In case of liquids,
carbon numbers were distributed within the C(5)-C(23) range depending on
the cracking parameters. Decomposition of the carbon chain could be
followed by GC and both by FTIR and SEC techniques in case of volatile
fractions and residues. Catalysts increased yields of valuable volatile
fractions and moreover catalysts caused both carbon chain isomerization
and switching of the position of double bonds. (c) 2007 Elsevier B.V.
All rights reserved.
CT 7th International Symposium and Summer School on Bioanalysis
CY JUN 10-17, 2007
CL Pecs, HUNGARY
TC 9
ZB 5
Z8 0
ZS 1
Z9 9
SN 0165-022X
UT WOS:000256393200069
ER
PT J
AU Li, Fangfei
Sun, Shenmei
Jiang, Yinshan
Xia, Maosheng
Sun, Mengmeng
Xue, Bing
TI Photodegradation of an azo dye using immobilized nanoparticles of TiO2
supported by natural porous mineral
SO JOURNAL OF HAZARDOUS MATERIALS
VL 152
IS 3
BP 1037
EP 1044
DI 10.1016/j.jhazmat.2007.07.114
PD APR 15 2008
PY 2008
AB Natural mordenite, replacing the synthetic zeolites, has been employed
as the support of TiO2, and its photocatalytic activity has been
examined in methyl orange (MO) aqueous under UV light. AFM, TEM, XRD,
IFTIR and fluorescence spectra have been used to reveal the loading
effects of TiO2 on mordenite. The results show that the photocatalytic
degradation (PCD) reaction rates are sharply increased by natural
zeolite supports. Since mordenite is photo-inert, the PCD-enhancement is
mostly caused by the bonding effects of Ti-O-Si and Ti-O-Al. Moreover,
another two distinct natural zeolites have been employed as the supports
of TiO2, in order to check the universality of PCD-enhancement effect of
natural zeolites on TiO2. And the factors of PCD reaction on
TiO2-zeolite, such as pH and catalyst dose, have been investigated. (C)
2007 Elsevier B.V. All rights reserved.
TC 28
ZB 7
Z8 5
ZS 0
Z9 32
SN 0304-3894
UT WOS:000255180600020
ER
PT J
AU Royaee, Sayed Javid
Falamaki, Cavus
Sohrabi, Morteza
Siamak, Sayed
Talesh, Ashraf
TI A new Langmuir-Hinshelwood mechanism for the methanol to dimethylether
dehydration reaction over clinoptilolite-zeolite catalyst
SO APPLIED CATALYSIS A-GENERAL
VL 338
IS 1-2
BP 114
EP 120
DI 10.1016/j.apcata.2008.01.011
PD APR 1 2008
PY 2008
AB The kinetic behavior of a modified clinoptilolite zeolite for the
methanol to dimethylether dehydration reaction has been investigated
using a differential fixed bed reactor. It was observed that at high
partial pressures, MeOH plays an inhibition role. A novel
Langmuir-Hinshelwood type reaction mechanism has been developed that
predicts the latter effect. (c) 2008 Elsevier B.V. All rights reserved.
TC 7
ZB 1
Z8 1
ZS 0
Z9 8
SN 0926-860X
UT WOS:000254905200016
ER
PT J
AU Tarasevich, Yu. I.
Polyakov, V. E.
Ivanova, Z. G.
Krysenko, D. A.
TI Obtaining and Properties of Clinoptilolite Modified by Manganese Dioxide
SO JOURNAL OF WATER CHEMISTRY AND TECHNOLOGY
VL 30
IS 2
BP 85
EP 91
DI 10.3103/S1063455X08020045
PD APR 2008
PY 2008
AB We have found optimal conditions for obtaining an effective
sorbent-catalyst based on natural clinoptololite with chemosorbed
manganese dioxide for removing Mn(2+) ions from water. Using a complex
of sorption-analytical, structure-sorption, electron-microscopic methods
we have studied the properties of the modifying delta-MnO(2)-film. The
mechanism of its sorption-catalytic effect on Mn(2+) has been discussed.
TC 2
ZB 0
Z8 0
ZS 0
Z9 2
SN 1063-455X
UT WOS:000263357800004
ER
PT J
AU Nikazar, Manouchehr
Gholivand, Khodayar
Mahanpoor, Kazem
TI Photocatalytic degradation of azo dye Acid Red 114 in water with TiO2
supported on clinoptilolite as a catalyst
SO DESALINATION
VL 219
IS 1-3
BP 293
EP 300
DI 10.1016/j.desal.2007.02.035
PD JAN 25 2008
PY 2008
AB In this investigation photocatalytic degradation of azo dye Acid Red 114
in water was studied. Titanium (IV) oxide was supported on
clinoptilolite (CP) (Iranian natural zeolite) using solid-state
dispersion (SSD) method. The results show that the TiO2/clinoptilolite
(SSD) are an active photocatalyst. The maximum effect of
photodegradation was observed at 10 wt.% TiO2, 90 wt% clinoptilolite. A
first order reaction with K = 0. 0127 min(-1) was observed for the
photocatalytic degradation reaction. The effects of sonic parameters
such as pH, amount of photocatalyst, and initial concentration of dye
were also examined. Based on the results, a model was proposed for
photodegradation of dyes using immobilized [TiO2/clinoptilolite (SSD)].
This model can be useful for the development of this technology for
wastewater treatment applications.
TC 32
ZB 7
Z8 2
ZS 0
Z9 33
SN 0011-9164
UT WOS:000252197100026
ER
PT J
AU Kartal, Ozlem Esen
Onal, Isik
TI Synthesis of ZSM-5 from modified clinoptilolite and its catalytic
activity in alkylation of benzene to ethylbenzene
SO CHEMICAL ENGINEERING COMMUNICATIONS
VL 195
IS 8
BP 1043
EP 1057
DI 10.1080/00986440801907078
PD 2008
PY 2008
AB ZSM-5 catalysts were prepared by utilizing clinoptilolite found in
Western Anatolia in abundant amounts as a type of natural zeolite.
Hydrothermal reaction was conducted with HCl-treated clinoptilolite at
180 degrees C. After characterizing the solid products obtained by this
reaction as ZSM-5 by means of XRD, IR, TGA, surface area analyzer, and
chemical analysis they were tested as catalysts in benzene alkylation
reaction with ethylene leading to ethylbenzene. Catalytic performance of
samples prepared in this study was investigated for benzene conversion,
ethylbenzene yield, and selectivity. It was found that ZSM-5(A) sample
showed performance similar to that of the reference sample (ZSM-5(C))
synthesized by using patented literature information in terms of benzene
conversion. When the reaction temperature was increased from 400 to 425
degrees C ethylbenzene yield and selectivity results of ZSM-5(A) sample
were improved but coke formation increased. Catalyst test results
indicated the possibility of using clinoptilolite as a raw material in
the synthesis of ZSM-5 catalyst for alkylation of benzene with ethylene
reaction.
TC 3
ZB 1
Z8 0
ZS 0
Z9 3
SN 0098-6445
UT WOS:000255301700011
ER
PT J
AU Fozooni, Samieh
Tikdari, Ahmad Momeni
Hamidian, Hooshang
TI COMPARISON OF CLINOPTILOLITE, ANALCIME AND YUGAWARALITE FOR SYNTHESIS OF
UNSATURATED 5(4H)-OXAZOLONES IN SOLVENT-FREE CONDITION AND MICROWAVE
IRRUDIATION
SO HETEROCYCLIC COMMUNICATIONS
VL 14
IS 1-2
BP 77
EP 82
PD 2008
PY 2008
AB In view of the importance of azlactones as synthons, biological
importance of the compounds and the advantages offered by coupling
microwave activation with dry media reactions, we report here a
solvent-free procedure for the synthesis of 2-phenyl-5(4H)-oxazolones
from aldehydes or ketons and hippuric acid using clinoptilolite,
analcime and yugawaralite under microwave irradiation according to green
chemistry.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0793-0283
UT WOS:000260108100012
ER
PT J
AU Maicaneanu, Andrada
Stanca, Maria
Burca, Silvia
Bedelean, Horea
TI Fe/ZVT CATALYSTS FOR PHENOL TOTAL OXIDATION
SO STUDIA UNIVERSITATIS BABES-BOLYAI CHEMIA
VL 53
IS 3
BP 7
EP 23
PD 2008
PY 2008
AB Zeolitic volcanic tuffs collected from Alunis (A-ZVT) area (Cluj County,
Romania) modified by ionic exchange with iron ions were tested, as
catalysts, in the wet air oxidation process in order to remove phenol
from synthetic wastewaters. The zeolitic volcanic tuff samples used as
support for the oxidation catalysts were characterised by means of
optical microscopy, scanning electron microscopy (SEM), X ray
diffraction (XRD), chemical analysis and Fourier transformed infrared
spectroscopy ( FTIR). In order to realize phenol catalytic wet air
oxidation we used a synthetic solution containing 1g phenol/dm(3) (100
cm(3)), which was contacted with 4 grams of Fe/ZVT catalyst in a batch
reactor with magnetic stirring. Air was introduced in the reactor using
a glass frit at different flow rates. Effect of reaction conditions,
temperature and air flow rate, over the phenol conversion and the
overall efficiency of the oxidation process were investigated. With the
increase of temperature and air flow rate we observed an increase of the
oxidation process efficiency. Activation energy was also calculated.
CT 1st Conference on Techniques of Chemical and Biochemical Remediation
(BIOREMED)
CY SEP 20-22, 2007
CL Babes Bolyal Univ, Fac Chem & Chem Engn, Cluj Napoca, ROMANIA
HO Babes Bolyal Univ, Fac Chem & Chem Engn
RI STANCA, MARIA/D-9099-2012; Maicaneanu, Andrada/B-6028-2011; BURCA, SILVIA/D-8868-2012
TC 1
ZB 1
Z8 0
ZS 0
Z9 2
SN 1224-7154
UT WOS:000263940900001
ER
PT J
AU Aykac, Hilal
Yilmaz, Selahattin
TI Hydrogenation of Citral over Ni and Ni-Sn Catalysts
SO TURKISH JOURNAL OF CHEMISTRY
VL 32
IS 5
BP 623
EP 633
PD 2008
PY 2008
AB Liquid phase citral hydrogenation over zeolite-supported monometallic Ni
and bimetallic Ni-Sn catalysts was studied. The zeolite support
materials were Na-Y, Na-mordenite, and clinoptilolite. Ni and Sn
contents of the monometallic and bimetallic catalysts were 8.1-9.2 wt%
and 0.46 wt%, respectively. The type of the zeolite support affected the
activity and selectivity of the catalysts differently. The main product
of the citral hydrogenation reaction was citronellal, for both
monometallic (84.5% yield) and bimetallic (44.5% yield) catalysts. The
addition of promoter increased the selectivity to unsaturated alcohols
(geraniol+ nerol), i.e. it changed from 0.9% to 6.3% over mordenite and
from 0.9% to 2.1% over Na-Y-supported catalysts. Furthermore, activity
of the Ni catalysts decreased while the quantity of acetal remained
almost constant. Intimate contact between active metal, promoter, and
support, and a catalyst with a high concentration of weak acid sites
gave high selectivity to geraniol+ nerol.
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 1300-0527
UT WOS:000260458500011
ER
PT S
AU Petranovskii, V.
Pestryakov, A. N.
Kazantseva, L. K.
Cruz, J.
Kryazhov, A. N.
BE Gedeon, A
Massiani, P
Babonneau, F
TI Formation of catalytically active copper and nickel nanoparticles in
natural zeolites
SO ZEOLITES AND RELATED MATERIALS: TRENDS, TARGETS AND CHALLENGES,
PROCEEDINGS OF THE 4TH INTERNATIONAL FEZA CONFERENCE
SE Studies in Surface Science and Catalysis
VL 174
BP 513
EP 516
PN 1
PD 2008
PY 2008
AB Structure, thermostability and catalytic properties of copper and nickel
nanoparticles in natural and synthetic zeolites (mordenite and
clinoptilolite) have been studied using methods of XRD, elemental
analysis, UV-visible spectroscopy, MAS NMR, TEM and catalytic testing.
Different electronic states of Cu and Ni were identified in zeolites.
Catalytic experiments showed efficiency of the studied catalysts in the
process of complete oxidation of hydrocarbons.
CT 4th Conference of the Federation of European Zeolite Associations (FEZA)
CY SEP 02-06, 2008
CL Univ Pierra Marie Curie, Paris, FRANCE
HO Univ Pierra Marie Curie
SP French Group Zeolites (GFZ)
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 0167-2991
BN 978-0-444-53297-8
UT WOS:000283749900107
ER
PT S
AU Royaee, S. J.
Sohrabi, M.
Falamaki, C.
BE Gedeon, A
Massiani, P
Babonneau, F
TI Transformation of a natural zeolite into solid catalyst for methanol to
dimethyl ether reaction and kinetics modeling
SO ZEOLITES AND RELATED MATERIALS: TRENDS, TARGETS AND CHALLENGES,
PROCEEDINGS OF THE 4TH INTERNATIONAL FEZA CONFERENCE
SE Studies in Surface Science and Catalysis
VL 174
BP 1207
EP 1210
PN 2
PD 2008
PY 2008
AB Clinoptilolite, a natural zeolite, has been investigated as the basic
raw material to synthesize a catalyst for methanol dehydration to
dimethyl ether and a novel kinetic model, based on Langmiure-
Hinshelwood method, was presented for the reaction with the optimized
catalyst and the kinetic parameters were determined as functions of
temperature. The modified clinoptilolite zeolite subject of this study
might be of high industrial interest because of the relative lower
activation energy (ca. 60 kJ mol(-1)) compared to other reported
zeolitic and nonzeolitic catalysts.
CT 4th Conference of the Federation of European Zeolite Associations (FEZA)
CY SEP 02-06, 2008
CL Univ Pierra Marie Curie, Paris, FRANCE
HO Univ Pierra Marie Curie
SP French Group Zeolites (GFZ)
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0167-2991
BN 978-0-44453-298-5
UT WOS:000283742800102
ER
PT J
AU Iznaga, I. Rodriguez
Petranovskii, V.
Fuentes, G. Rodriguez
Mendoza, C.
Aguilar, A. Benitez
TI Exchange and reduction of Cu2+ ions in clinoptilolite
SO JOURNAL OF COLLOID AND INTERFACE SCIENCE
VL 316
IS 2
BP 877
EP 886
DI 10.1016/j.jcis.2007.06.021
PD DEC 15 2007
PY 2007
AB The ion-exchange and reduction processes for Cu2+ ions in clinoptilolite
from the Caimanes deposit (Moa, Cuba) were studied at different
temperatures. The ion-exchange studies were done to determine the
kinetic parameters of Cu2+ removal from solution by this clinoptilolite
modified previously to NH4+ form, and thermodynamic parameters of Cu2+
elution from zeolite using NH4Cl solution. The results show that
temperature increase favors the exchange and that it is a reversible
process. The external diffusion rate appreciably increases with
temperature, while, the internal diffusion coefficient rises relatively
little. This means that besides ion exchange other processes (such as
precipitation of the low-solubility phase and/or salt adsorption) occur,
which cause copper removal from solution and affect the intracrystalline
diffusion of the ions. For steric reasons the exchange of
[Cu(H2O)(6)](2+) ions from a solution must occur with a number of water
molecules n smaller than 6 (6 > n >= 0). Cu2+ reduction by hydrogen and
the formation of Cu-particles in the clinoptilolite were verified. The
Cu2+ reduction mechanism is complex, should be present in the reduced
indirect, and sensitive to reduction temperature; consequently, Cu-n(+)
states intermediate between Cu2+ and Cu-0 samples. (C) 2007 Elsevier
Inc. All rights reserved.
TC 14
ZB 3
Z8 1
ZS 0
Z9 15
SN 0021-9797
UT WOS:000250987500078
ER
PT J
AU Grancaric, Ana Marija
Markovic, Lea
Tarbuk, Anita
TI Active multifunctional cotton treated with zeolite nanoparticles
SO TEKSTIL
VL 56
IS 9
BP 533
EP 542
PD SEP 2007
PY 2007
AB Natural zeolites are aluminosilicate crystals with unique absorption and
catalyst properties. In medicine they are attributed anticancerogen,
antiallergic, antiseptic, antireumatic and other properties. They also
exert a strong influence on blood circulation improvement. Addition of
zeolite nanoparticles in different textile pretreatment and treatment
phases is a novelty in textile finishing for multifunctional protection
effects. Zeolites make a contribution to UV protection since they
disperse UV radiation unlike other agents which absorb it and prevent
their transmission. If zeolites are added to azalides in textile
finishing, they increase their efficacious antimicrobial action. The
paper describes cotton knitted fabric mercerized and bleached with
addition of activated zeolite, clinoptilolite nanoparticles and treated
with azalide to achieve multifunctional protection. Clinoptilolite was
added into baths for cotton pretreatment, treatment and modification.
Properties of the treated cotton were determined by international
standards (EN, ISO, AS/NZS, AATCC).
TC 2
ZB 0
Z8 0
ZS 0
Z9 2
SN 0492-5882
UT WOS:000255247800001
ER
PT J
AU Grancaric, Ana Marija
Markovic, Lea
Tarbuk, Anita
TI Active multifunctional cotton treated with zeolite nanoparticles
SO TEKSTIL
VL 56
IS 9
BP 543
EP 553
PD SEP 2007
PY 2007
AB Natural zeolites are aluminosilicate crystals with unique absorption and
catalyst properties. In medicine they are attributed antitumor,
antiallergic, antiseptic, antireumatic and other properties. They also
exert a strong influence on blood circulation improvement. Addition of
zeolite nanoparticles in different textile pre-treatment and treatment
phases is a novelty in textile finishing for multifunctional protection
effects. Zeolites make a contribution to UV protection since they
disperse UV radiation unlike other agents which absorb it and prevent
their transmission. If zeolites are added to azalides in textile
finishing, they increase their efficacious antimicrobial action. The
paper describes cotton knitted fabric mercerized and bleached with
addition of activated zeolite, clinoptilolite nanoparticles and treated
with azalide to achieve multifunctional protection. Clinoptilolite was
added into baths for cotton pretreatment, treatment and modification.
Properties of the treated cotton were determined by international
standards (EN, ISO, AS/NZS, AATCC).
TC 4
ZB 0
Z8 0
ZS 0
Z9 4
SN 0492-5882
UT WOS:000255247800002
ER
PT J
AU Pacheco-Malagon, G.
Sanchez-Flores, Norma. A.
Saniger-Blesa, J.
Banos, L.
Perez-Romo, P.
Valente, Jaime S.
Guzman-Castillo, Maria de L.
Hernandez-Beltran, F.
Fripiat, Jose J.
TI New synthesis technique of supported ZSM-5 using organo-alumino-silicic
gels
SO MICROPOROUS AND MESOPOROUS MATERIALS
VL 100
IS 1-3
BP 70
EP 76
DI 10.1016/j.micromeso.2006.09.043
PD MAR 23 2007
PY 2007
AB This contribution deals with the synthesis of a silicon-rich ZSM-5
obtained from an amorphous organo-alumino-silicic gel. The gel was
formed by reacting a mechanical mixture of RHA (rice hull ash), silica's
source, and of natural clinoptilolite, source of alumina, with glycerol
during 2 h at 200 degrees C. After a maturation period of one day at 60
degrees C, the reaction product was hydrolyzed by a tetra-propylammonium
(TPA) solution and then aged for two days at 135 degrees C in a
stainless steel autoclave. After washing and drying, the X-ray pattern
showed a well crystallized ZSM-5. The textural analysis of the slowly
calcined solid at 500 degrees C for 4 It, and the SEM micrographics
evidence that the zeolite was supported on mesoporous silica. The
proportion of both components depends on the tunable hydrolysis
conditions. (c) 2006 Elsevier Inc. All rights reserved.
RI S. Valente, Jaime/B-3605-2013
OI S. Valente, Jaime/0000-0002-2150-7869
TC 6
ZB 1
Z8 0
ZS 0
Z9 6
SN 1387-1811
UT WOS:000244798300010
ER
PT J
AU Nikazar, M.
Gholivand, K.
Mahanpoor, K.
TI Using TiO2 supported on clinoptilolite as a catalyst for photocatalytic
degradation of azo dye disperse yellow 23 in water
SO KINETICS AND CATALYSIS
VL 48
IS 2
BP 214
EP 220
DI 10.1134/S002315840702005X
PD MAR 2007
PY 2007
AB In this investigation photocatalytic degradation of azo dye Disperse
yellow 23 in water was studied. Titanium (IV) oxide was supported on
Clinoptilolite (CP) (Iranian Natural Zeolite) using the solid-state
dispersion (SSD) method. The results show that the TiO2/Clinoptilolite
(SSD) is an active photocatalyst. The maximum effect of photo
degradation was observed at 10 wt % TiO2, 90 wt % Clinoptilolite. A
first order reaction with k = 0.0119 min(-1) was observed. The effects
of some parameters such as pH, amount of photocatalyst, and the initial
concentration of dye were examined.
TC 10
ZB 2
Z8 0
ZS 0
Z9 10
SN 0023-1584
UT WOS:000245978000005
ER
PT J
AU Yeniova, H.
Karaduman, A.
Alibeyli, R.
TI Isomerization, disproportionation and hydrocracking of
1,3,5-trimethyllbenzene and n-decane mixture over natural clinoptilolite
zeolites
SO PETROLEUM SCIENCE AND TECHNOLOGY
VL 25
IS 3-4
BP 387
EP 398
DI 10.1081/LFT-200063076
PD MAR-APR 2007
PY 2007
AB Five different catalysts were prepared from the ammonium form of the
dealuminated natural zeolite clinoptilolite occurs in Gordes, Turkey.
The effect of reaction temperature on the activity and selectivity is
studied over each catalyst by employing 1,2,3 Trimethylbenzene
(1,2,3-TMB) and n-decane (90:10) model mixture as feedstock. Effects of
the catalyst type and reaction temperature on the isomerization,
disproportionation, and hydrocracking reactions are discussed. The
1,3,5-TMB conversion increased by the temperature increment for all
catalysts. Highest 1,3,5-TMB conversion (> 40%) and highest selectivity
for the isomerization (> 80%) was reached over the dealuminated and
nickel-deposited clinoptilolite catalyst (NiDK).
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 1091-6466
UT WOS:000246181700007
ER
PT J
AU Martins, Leandro
Boldo, Renato Toloni
Cardoso, Dilson
TI Ion exchange and catalytic properties of methylammonium FAU zeolite
SO MICROPOROUS AND MESOPOROUS MATERIALS
VL 98
IS 1-3
BP 166
EP 173
DI 10.1016/j.micromeso.2006.08.023
PD JAN 5 2007
PY 2007
AB Ion exchange of methylammonium cations (Me) in Na-Y zeolite (FAU) and
the properties of the resulting Me-Y material (Me = (CH3)(i)NH4-i+; i =
0-4) was studied. Results indicated that the ion exchange equilibrium
can quickly be reached, even when voluminous tetramethylammonium cations
are used. XRD results indicated that the cation distribution along
zeolite crystals is uniform but, due to stereo-spatial reasons,
methylammonium cation cannot replace all sodium cations present in the
zeolite: the ion exchange of organic cations is restricted to the
supercavity. XRD also shows that as the voluminous methylammonium
cations are incorporated in compensation sites, they produce an
expansion of the unit cell of the Faujasite. Physisorption of nitrogen
evidences that as the ion exchange level increases, the volume of
micropores available in the zeolite crystals decreases proportionally.
For the first time, the Me-Y zeolites, containing methylammonium cations
in charge compensation sites, were evaluated as basic catalysts in
Knoevenagel condensation, producing much higher yields than the ones
obtained with cesium faujasite. These unique results open new
perspectives for the use of these low-cost organic containing zeolites,
in processes when the presence of basic sites is necessary. (C) 2006
Elsevier Inc. All rights reserved.
RI Cardoso, Dilson/F-9437-2012
OI Cardoso, Dilson/0000-0003-3504-4516
TC 16
ZB 1
Z8 0
ZS 1
Z9 16
SN 1387-1811
UT WOS:000243695000022
ER
PT S
AU Popovici, Eveline
Sulitanu, Nicolae
Dvininov, Emiliana
Misaelidis, Panagiotis
BE Xu, R
Gao, Z
Chen, J
Yan, W
TI Preparation and characterization of palladium supported on heulandite
SO FROM ZEOLITES TO POROUS MOF MATERIALS: THE 40TH ANNIVERSARY OF
INTERNATIONAL ZEOLITE CONFERENCE, PROCEEDINGS OF THE 15TH INTERNATIONAL
ZEOLITE CONFERENCE
SE Studies in Surface Science and Catalysis
VL 170
BP 2134
EP 2140
PD 2007
PY 2007
AB Palladium modified heulandite single crystals by treatment with
Pd(NH3)(4)Cl-2 aqueous solutions under different experimental conditions
were achieved. Pd nanoparticles with controlled size (d(Pd) approximate
to 10 nm) were formed within the heulandite structure. The resulting
materials were investigated by powder- XRD, AFM, TEM and UV-Vis
techniques. Their particle size dimensions were determined by XRD using
the Scherrer equation, and verified by AFM and TEM.
The structure of the heulandite with channel form and dimensions at the
molecular level was found to play the role of a template controlling the
size and distribution of the formed Pd-nanoparticles.
CT 15th International Zeolite Conference
CY AUG 12-17, 2007
CL Beijing, PEOPLES R CHINA
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0167-2991
BN 978-0-444-53068-4
UT WOS:000291657600288
ER
PT J
AU Royaee, S. J.
Sohrabi, A.
Falamaki, C.
TI Methanol dehydration to dimethyl ether using modified clinoptilolite
SO MATERIALS SCIENCE-POLAND
VL 25
IS 4
BP 1149
EP 1160
PD 2007
PY 2007
AB Clinoptilolite, a natural zeolite from the Semnan region in the West of
Iran, has been converted to a catalyst for the methanol dehydration to
dimethyl ether process. To produce such a catalyst and to create acidic
sites on the latter, the ion-exchange process has been used. In
addition, to investigate and optimize the effective factors of the
catalyst synthesis process, a L9 Taguchi experimental design method has
been implemented. The effects of four factors have been considered: the
type of ion-exchange solution (2 levels); ion-exchange solution
concentration; calcination temperature and calcination time (the last
three factors have been studied in 3 levels). The yield of catalyst
(conversionxselectivity) has been chosen as the response of the system.
The catalytic behaviour of the produced samples was investigated using a
fixed bed reactor (T = 350 degrees C, P = 1 atm and WHSV = 4.78 h(-1)).
The results of the statistical design showed that the optimum conditions
were: calcination time - 3 h, calcination temperature - 500 degrees C,
ion-exchange solution concentration - 2M, and ion-exchange solution -
ammonium chloride. The optimum catalyst was tested using a fixed bed
reactor at 330 degrees C, 1 atm and WHSV = 3.8 h(-1) resulting in 98.1%
conversion and 96.5% selectivity. In order to investigate the catalyst
behaviour under industrial operating conditions, the catalyst was tested
in a fixed bed reactor at 300 degrees C, 16 atm pressure, and WHSV =
52.5 h(-1). The results were 67.02% conversion and 99.74% selectivity.
TC 3
ZB 0
Z8 0
ZS 0
Z9 3
SN 0137-1339
UT WOS:000253376600024
ER
PT J
AU Wang, Yi
Kmiya, Yuichi
Okuhara, Toshio
TI Removal of low-concentration ammonia in water by ion-exchange using
Na-mordenite
SO WATER RESEARCH
VL 41
IS 2
BP 269
EP 276
DI 10.1016/j.watres.2006.10.035
PD JAN 2007
PY 2007
AB Removal of low-concentration ammonia (2-10 ppm) in water by ion exchange
with Na-form zeolites was investigated using a flow system at 278-333 K.
Results indicated that Na-mordenite was the most efficient
cation-exchanger (compared with Na-ferrierite, Na-ZSM-5, Na-beta, and
Na-Y, as well as the K- and H-form mordenite) for the removal of
low-concentration ammonia. The ammonia uptake and the ion-exchange level
achieved using mordenite with NH4+ for removal of 10 ppm ammonia at 333
K were 1.21 mmol g(-1) and 79.1%, respectively The high efficiency of
Na-mordenite for removal of low-concentration ammonia in water is due to
the strong acidity of the corresponding H-form mordenite as demonstrated
by ammonia temperature-programmed desorption. Ammonia uptake on the
Na-mordenite was minimally influenced by operating temperature in the
range of 278-333 K. The coexistent K+ and Na+ in water had little
influence on ammonia uptake of the Na-mordenite. In contrast, coexistent
Ca2+ and Mg2+ significantly lowered the efficiency of the Na-mordenite
for ammonia removal. (c) 2006 Elsevier Ltd. All rights reserved.
TC 16
ZB 6
Z8 0
ZS 0
Z9 16
SN 0043-1354
UT WOS:000244108500001
ER
PT J
AU Putun, E
Uzun, BB
Putun, AE
TI Fixed-bed catalytic pyrolysis of cotton-seed cake: Effects of pyrolysis
temperature, natural zeolite content and sweeping gas flow rate
SO BIORESOURCE TECHNOLOGY
VL 97
IS 5
BP 701
EP 710
DI 10.1016/j.biortech.2005.04.005
PD MAR 2006
PY 2006
AB Catalyzed pyrolysis of cotton-seed cake was studied under different
experimental conditions. Variables investigated were pyrolysis
temperature, zeolite content and sweeping gas flow rate. Experiments
were carried out isothermally. Liquids, gases and char were obtained as
products of pyrolysis. The distributions of these products were
determined for various contents (1, 5, 10, 20 wt.% of raw material) of
zeolite at four different pyrolysis temperatures. The maximum liquid
yield obtained was 30.84% at a pyrolysis temperature of 550 degrees C
with a sweeping gas flow rate of 100 cm 3 min(-1) in the presence of
clinoptilolite (20% based on raw material) as catalyst. The pyrolytic
and catalytic liquid products were analysed in detail to determine the
predominant chemical classes and the identities of the major compounds
present. (c) 2005 Elsevier Ltd. All rights reserved.
TC 32
ZB 5
Z8 2
ZS 0
Z9 34
SN 0960-8524
UT WOS:000234909300001
ER
PT J
AU Miskolczi, N
Bartha, L
Deak, G
TI Thermal degradation of polyethylene and polystyrene from the packaging
industry over different catalysts into fuel-like feed stocks
SO POLYMER DEGRADATION AND STABILITY
VL 91
IS 3
BP 517
EP 526
DI 10.1016/j.polymdegradstab.2005.01.056
PD MAR 2006
PY 2006
AB Thermal degradation of waste polymers was carried Out as a suitable
technique for converting plastic polymers into liquid hydrocarbons,
which could be used as feed stock materials. The catalytic degradation
of waste plastics (polyethylene and polystyrene) was investigated in a
batch reactor over different catalysts (FCC, ZSM-5 and clinoptillolite).
The effects of catalysts and their average grain size on the properties
of main degradation products (gases, gasoline, diesel oil) are
discussed. The temperature range of 410-450 degrees C was used in the
process. Both equilibrium FCC catalyst and natural clinoptilolite
zeolite catalyst had good catalytic activity to produce light
hydrocarbon liquids, and ZSM-5 catalyst produced the highest amount of
gaseous products. Gases and liquids formed in cracking reactions were
analyzed by gas chromatography. The liquid products Consisted of a wide
spectrum of hydrocarbons distributed within the C-5-C-28 carbon number
range depending on the cracking parameters. The composition of
hydrocarbons had linear non-branched structure in case of polyethylene,
while from polystyrene more aromatics (ethyl-benzene, styrene, toluene,
and benzene) were produced. The yields of volatile products increased
with increasing degradation temperature. The olefin content of liquids
was measured with an infrared technique and an olefin concentration of
50-60% was observed. The concentration Of Unsaturated compounds
increased with decreasing temperature, and in the presence of catalysts.
The activation energies were calculated oil the basis of the composition
of volatile products. The apparent activation energies were decreased by
catalysts and catalyst caused both carbon-chain and double bond
isomerisation. (c) 2005 Elsevier Ltd. All rights reserved.
CT 3rd International Conference on Polymer Modification, Degradation and
Stabilisation
CY AUG, 2004
CL Lyon, FRANCE
TC 36
ZB 4
Z8 0
ZS 1
Z9 37
SN 0141-3910
UT WOS:000234162800016
ER
PT J
AU Ghiaci, M
Abbaspur, A
Kalbasi, RJ
TI Internal versus external surface active sites in ZSM-5 zeolite - Part 1.
Fries rearrangement catalyzed by modified and unmodified H(3)PO(4)/ZSM-5
SO APPLIED CATALYSIS A-GENERAL
VL 298
BP 32
EP 39
DI 10.1016/j.apcata.2005.09.015
PD JAN 10 2006
PY 2006
AB The Fries rearrangement of phenylacetate has been studied in the
vapor-phase at 623 K over a series of surface modified and unmodified
ZSM-5 (Si/Al = 60-170) loaded with H(3)PO(4), differing in the external
surface treatment of the zeolites. When the external surface of the
zeolite is blocked with a surfactant before loading it with H(3)PO(4),
the selectivity to form the 4-hydroxyacetophenone was higher. This
superior performance of the externally blocked catalysts, relative to
the unmodified H(3)PO(4)/ZSM-5 catalyst, shows that by blocking the
external surface area of the ZSM-5 support, it exhibits a superior
catalytic selectivity than the unmodified catalyst.
Catalysts containing 0-4.9 wt.% P were prepared using modified and
unmodified ZSM-5 zeolites, and their catalytic performance for
vapor-phase Fries rearrangement of phenylacetate to
2-hydroxyacetophenone (2-HAP), 4-hydroxyacetophenone (4-HAP) and
4-acetoxyacetophenone (4-AAP) was determined. The influence of the
operating parameters on the performance of H(3)PO(4)/ZSM-5-surf
catalysts was also investigated. (c) 2005 Elsevier B.V. All rights
reserved.
TC 14
ZB 2
Z8 2
ZS 0
Z9 16
SN 0926-860X
UT WOS:000234623900005
ER
PT J
AU Nimwattanakul, W
Luengnaruemitchai, A
Jitkarnka, S
TI Potential of Ni supported on clinoptilolite catalysts for carbon dioxide
reforming of methane
SO INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
VL 31
IS 1
BP 93
EP 100
DI 10.1016/j.ijhydene.2005.02.005
PD JAN 2006
PY 2006
AB Carbon dioxide reforming of methane to synthesis gas has been
investigated with Ni-supported clinoptilolite catalysts. The catalysts
were prepared by using the incipient wetness impregnation method. The
catalytic activity of Ni supported on clinoptilolite with varying Ni
loadings was determined and the results showed that at 700 degrees C, 8
wt% Ni/clinoptilolite gave the highest activity. It exhibited not only
the highest activity and selectivity but also remarkable stability.
Moreover, both the activity and stability of this catalyst were observed
to vary with the Zr content, exhibiting a maximum at a composition of 2%
Zr. The amount of carbonaceous deposits on the spent catalysts was
further investigated by temperature-programmed oxidation (TPO) and
thermogravimetric analyzer (TGA) studies. (c) 2005 International
Association for Hydrogen Energy. Published by Elsevier Ltd. All rights
reserved.
TC 23
ZB 0
Z8 2
ZS 0
Z9 24
SN 0360-3199
UT WOS:000235538700012
ER
PT J
AU Li, FF
Jiang, YS
Yu, LX
Yang, ZW
Hou, TY
Sun, SM
TI Surface effect of natural zeolite (clinoptilolite) on the photocatalytic
activity of TiO2
SO APPLIED SURFACE SCIENCE
VL 252
IS 5
BP 1410
EP 1416
DI 10.1016/j.apsusc.2005.02.011
PD DEC 15 2005
PY 2005
AB The surface interaction between TiO2 and natural zeolite,
clinoptilolite, has been investigated by means of transmission electron
microscope (TEM), atom force microscope (AFM), X-ray diffractometer
(XRD), diffuse reflectance infrared Fourier transform (DRIFT) and far
Fourier transform infrared ray (FTIR) spectroscopy. And the
photocatalytic degradation (PCD) rate of methyl orange (MO), a model of
recalcitrant azo dye, in aqueous system has been measured to compare the
photocatalytic. activities of different photocatalysts. A model has been
carried out to explain the incorporation between TiO2 Particles and
natural zeolite. The results show that the TiO2 particles loaded on
zeolite are 50 nm or so, smaller than the pure one, and combine with
zeolite via chemical force. Since the reserved adsorption ability and
the existence of electron trapper, the TiO2-zeolite performed more
efficient at low initial concentration and in the later period of PCD
process, as compared with pure TiO2 nanopowders. (c) 2005 Elsevier B.V.
All rights reserved.
TC 32
ZB 3
Z8 3
ZS 0
Z9 34
SN 0169-4332
UT WOS:000233985900027
ER
PT J
AU Kaya, N
Karadurmus, E
Alicilar, A
TI Catalytic air oxidation of manganese in synthetic waters
SO CENTRAL EUROPEAN JOURNAL OF CHEMISTRY
VL 3
IS 3
BP 511
EP 519
DI 10.2478/BF02479279
PD JUL 2005
PY 2005
AB An attempt was made to study the oxidation of manganese by air in
synthetic waters. A series of batch experiments were performed at
different values of concentration, temperature and pH. Unoxidized
manganese in the solution was determined by formaldoxime spectrometric
method. Results of these studies indicated that the air oxidation of
manganese soluble in water can be effectively performed in basic media
and that oxidation yield increased with an increase in pH and
concentration. The yield was very high in the presence of manganese
dioxide, sepiolite or clinoptilolite in solution and, the oxidation was
almost completed especially at high values of pH and concentration. The
reaction was found to be first order with respect to Mn2+ with a very
low activation energy. A yield of 62% was obtained for the air oxidation
of wastewater taken from the treatment plant of Corum Municipality. (C)
Central European Science Journals. All rights reserved.
TC 2
ZB 1
Z8 0
ZS 0
Z9 2
SN 1644-3624
UT WOS:000230619800012
ER
PT J
AU Yilmaz, S
Ucar, S
Artok, L
Gulec, H
TI The kinetics of citral hydrogenation over Pd supported on clinoptilolite
rich natural zeolite
SO APPLIED CATALYSIS A-GENERAL
VL 287
IS 2
BP 261
EP 266
DI 10.1016/j.apcata.2005.04.002
PD JUN 22 2005
PY 2005
AB The liquid phase hydrogenation of citral has been investigated over Pd
(2.42%) supported on clinoptilolite rich natural zeolite catalyst for
different reaction conditions. The zeolite support did not affect the
active metal properties. This was attributed to the large size of Pd
particles on the support. High selectivity (90%) to citronellal was
obtained at complete conversion of citral. The catalytic activity
increased with reaction temperature (80, 100, 120 degrees C following an
Arrhenius behaviour, while selectivity remained constant for a given
conversion. Selectivity to citronellal increased from 78 to 90% with
increase in the amount of catalyst in the reaction solution (Citral/Pd
mole ratio 293, 176 and 105). The spent catalyst regained its fresh
activity and selectivity upon regeneration. (c) 2005 Elsevier B.V. All
rights reserved.
TC 15
ZB 0
Z8 1
ZS 1
Z9 15
SN 0926-860X
UT WOS:000230209000014
ER
PT J
AU Pestryakov, A. N.
Petranovskii, V. P.
Lunin, V. V.
Kryazhov, A. N.
TI Study of electronic states of supported copper in catalytic systems
SO REVISTA MEXICANA DE FISICA
VL 51
IS 2
BP 117
EP 121
SU S
PD JUN 2005
PY 2005
AB Different states of copper have been identified on the surface of
gamma-Al2O3, mordenite, erionite, clinoptilolite, pumice, and foam
copper catalysts by UV-Vis and IR spectroscopy. Zeolite copper shows the
highest dispersion, while on the surface of pumice and bulk metal, the
portion of oxidized states of copper is small. The modifiers produce a
direct effect on the electronic properties of dispersed copper. Ce and
Zr oxides cause an increase on the effective charge of copper ions,
stabilizing the oxidized state. In contrast, La and Cs oxides lower the
effective charge of Cu+ and Cu-n(delta+), and favor their fast
reduction.
CT 2nd International Conference on Physical Engineering
CY JUL 29-AUG 02, 2002
CL Mexico City, MEXICO
SP Autonomous Metropolitan Univ, Basic Sci Dept; AMU, Phys Engn Studies
Comm
RI Pestryakov, Alexey/J-5889-2013
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 0035-001X
UT WOS:000244651100021
ER
PT J
AU Unveren, E
Gunduz, G
Cakicioglu-Ozkan, F
TI Isomerization of alpha-pinene over acid treated natural zeolite
SO CHEMICAL ENGINEERING COMMUNICATIONS
VL 192
IS 3
BP 386
EP 404
DI 10.1080/00986440590477773
PD MAR 2005
PY 2005
AB In this study, isomerization of alpha-pinene was studied over several
acid-treated natural zeolite catalysts rich in clinoptilolite. Zeolite
samples were contacted with HCl at different concentrations at
30degreesC or at 60degreesC for 3 and 24 hours and tested in
isomerization reaction of alpha-pinene. The catalysts prepared were
characterized by XRD, nitrogen adsorption, and acidity studies. Acidity
strength and the distribution of Lewis and Bronsted acid sites of the
catalysts were determined, and their catalytic activities in
alpha-pinene isomerization and selectivities to main reaction products,
camphene and limonene, were investigated. Acid treatment improved the
selectivity of catalyst samples to camphene, decreasing the selectivity
to limonene, probably forcing limonene to secondary reactions at high
conversions.
The kinetics of alpha-pinene consumption was described by first-order
kinetics. Two kinetic models were tested for the reaction mechanism and
one model was found to give a good correlation between the theoretical
and experimental data. In the models, the key intermediate was the
pinylcarbonium ion, which was formed irreversibly from alpha-pinene.
Number and distribution of Lewis and Bronsted acid sites affect the
formation of bicyclic and monocyclic products.
TC 3
ZB 1
Z8 0
ZS 0
Z9 3
SN 0098-6445
UT WOS:000226534800010
ER
PT J
AU Miskolczi, N
Bartha, L
Deak, G
Jover, B
Kallo, D
TI Thermal and thermo-catalytic degradation of high-density polyethylene
waste
SO JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
VL 72
IS 2
BP 235
EP 242
DI 10.1016/j.jaap.2004.07.002
PD NOV 2004
PY 2004
AB Thermal and thermo-catalytic cracking behaviour of a commercial
high-density polyethylene (HDPE) waste was investigated in the
temperature range of 400-450 degreesC in a laboratory scale pyrex batch
reactor. An equilibrium fluid catalytic cracking catalyst (FCC), HZSM-5
and a clinoptilolite containing rhyolite tuff were used as catalysts.
The presence of a catalyst significantly altered both the yield and
composition of the products and differences were found between catalysts
having different acidities, micro- and macropore surface areas. The
yield of gases increased in the order: non-thermo-catalytic cracking < clinoptilolite < FCC < HZSM-5 catalysed cracking, while the yields of liquid products increased in the sequence of non-thermo-catalytic cracking < clinoptilolite < HZSM-5 < FCC catalysed cracking. The catalysts significantly affected the isomerization of the olefin double bond and of the carbon-chain of the cracked products, the olefin content of liquids did not differ considerably. The effect of the catalysts on the yields and structure of products were getting less significant with increasing cracking temperature. The range of the carbon atom number in liquids was C-5-C-28 in non-thermo-catalytic cases, whereas using catalysts it was C-5-C-25, but the temperature of cracking had a noticeable effect on the distribution of carbon atom. Each liquid fraction is of low sulphur content, which may be advantageous for application as fuel. (C) 2004 Elsevier B.V. All rights reserved. TC 31 ZB 2 Z8 1 ZS 0 Z9 32 SN 0165-2370 UT WOS:000225234900007 ER PT J AU Moreno-Tost, R Santamaria-Gonzalez, J Rodriguez-Castellon, E Jimenez-Lopez, A Autie, MA Gonzalez, E Glacial, MC Pozas, CD TI Selective catalytic reduction of nitric oxide by ammonia over Cu-exchanged Cuban natural zeolites SO APPLIED CATALYSIS B-ENVIRONMENTAL VL 50 IS 4 BP 279 EP 288 DI 10.1016/j.apcatb.2004.01.019 PD JUL 15 2004 PY 2004 AB The catalytic selective reduction of NO over Cu-exchanged natural zeolites (mordenite (MP) and clinoptilolite (HC)) from Cuba using NH3 as reducing agent and in the presence of excess oxygen was studied. Cu(II)-exchanged zeolites are very active catalysts, with conversions of NO of similar to95%, a high selectivity to N-2 at low temperatures, and exhibiting good water tolerance. The chemical state of the Cu(II) in exchanged zeolites was characterized by H-2-TPR and XPS. Cu(II)-exchanged clinoptilolite underwent a severe deactivation in the presence of SO2. However, Cu(II)-exchanged mordenite not only maintained its catalytic activity, but even showed a slight improvement after 20 h of reaction in the presence of 100 PPM of SO2. (C) 2004 Elsevier B.V. All rights reserved. TC 26 ZB 1 Z8 0 ZS 0 Z9 26 SN 0926-3373 UT WOS:000221969800009 ER PT J AU Akpolat, O Gunduz, G Ozkan, F Besun, N TI Isomerization of alpha-pinene over calcined natural zeolites SO APPLIED CATALYSIS A-GENERAL VL 265 IS 1 BP 11 EP 22 DI 10.1016/j.apcata.2003.12.055 PD JUN 30 2004 PY 2004 AB In this work, isomerization reaction of alpha-pinene was studied over several heat-treated natural zeolite catalysts, rich in clinoptilolite, from Balykesir-Bigadic region in Turkey in a batch slurry reactor under nitrogen atmosphere. Zeolite samples were calcined at different temperatures such as 300, 450 and 600degreesC. All catalysts were tested in the isomerization reaction of alpha-pinene and were characterised by nitrogen adsorption experiments, IR, and XRD measurements. Acidity strength and the distribution of Lewis and Bronsted acid sites of the samples were determined. Selectivities to main reaction products, camphene and limonene, and reaction kinetics were investigated. Catalytic activity, that is total conversion of alpha-pinene, of heat-treated samples decreased with increasing calcination temperatures. Selectivity to limonene is dependent on alpha-pinene conversion at high conversion levels while the selectivity to camphene is not. The formation of heavy products increased with treatment temperature. It was seen that alpha-pinene consumption could be described by a first-order kinetics. (C) 2004 Elsevier B.V. All rights reserved. TC 26 ZB 2 Z8 1 ZS 0 Z9 27 SN 0926-860X UT WOS:000221630100002 ER PT J AU Miskolczi, N Bartha, L Deak, GY Jover, B Kallo, D TI Kinetic model of the chemical recycling of waste polyethylene into fuels SO PROCESS SAFETY AND ENVIRONMENTAL PROTECTION VL 82 IS B3 BP 223 EP 229 DI 10.1205/095758204323065984 PD MAY 2004 PY 2004 AB Tertiary recycling methods offer potential possibilities for the utilization of waste plastics. Thermal and catalytic degradation of low-density polyethylene wastes were studied in a batch reactor under mild cracking conditions to derive liquid cracking products of olefins and paraffins. Zeolite catalysts with different activities were studied: a commercial equilibrium FCC catalyst, an H form ZSM-5 catalyst, and a natural clinoptilolite containing rhyolite tuff. The catalytic processes could convert waste polymers into valuable hydrocarbons. The properties of products could be modified by the use of catalysts. The olefin content and the position of the olefinic double bonds were investigated with IR spectrometry. In the presence of catalysts the olefin content increased, and the terminal bonds migrated into internal positions. Furthermore the liquid products had lower average molecular weights than those obtained without catalysts. The activation energies of the cracking reactions with or without catalysts were determined. The apparent activation energy was lower in catalytic than that in thermal degradation. The cracking reaction rates were modelled and the reaction rate constant of each hydrocarbon type was calculated. The model gives a good approximation of the experimental results obtained from the degradation of LDPE waste in the presence and absence of catalysts. Under the studied parameters, liquids were formed with suitable properties for further uses (e.g. low sulphur content, low pour point). TC 4 ZB 1 Z8 0 ZS 0 Z9 4 SN 0957-5820 UT WOS:000221651600005 ER PT J AU Barker, JM Freeman, PS Austin, GS Bowman, RS TI Development of value-added zeolite products from St. Cloud Mining SO CIM BULLETIN VL 97 IS 1077 BP 52 EP 58 PD FEB 2004 PY 2004 AB The physical, chemical and mineralogic characteristics of zeolites allow commercially Important applications. While adoption of zeolite technology is slow in the United States compared to other regions of the world, continued testing and research has shown a wide range of uses for these minerals. They are important catalysts in petroleum refining, molecular sieves able to separate gases, and chemically inert carriers of reactants. The zeolite clinoptilolite produced by St, Cloud Mining Company (clino) (SC) is used in animal hygiene and animal feed, especially concentrated animal feeding operations (CAFOs), horticulture, water treatment, floor dry, aquariums, air and other filters, and odour control. Clino can remove cations from solution, and surface-modified zeolite (SMZ) is a sorbent for the removal of anions and neutral organics from water. Specific clino applications are: control of chemical pollution in groundwater, removal of organic compounds from oil field waters, and elimination of pathogens from sewage effluent. Combining the sorption capabilities of SMZ with chemical or biological transformations can yield complete removal of toxic materials from contaminated water. Continued development and marketing of zeolite products will be a growth market far into the future. The CAFO market for zeolites is the most significant growth area in the United States over the next few years. SMZ, currently less than 1% of St. Cloud sales, will continue to gain market penetration for many years. TC 1 ZB 1 Z8 0 ZS 0 Z9 1 SN 0317-0926 UT WOS:000189113900008 ER PT J AU Kim, JR Van, JH Park, DW Lee, MH TI Catalytic degradation of mixed plastics using natural clinoptilolite catalyst SO REACTION KINETICS AND CATALYSIS LETTERS VL 81 IS 1 BP 73 EP 81 DI 10.1023/B:REAC.0000016519.59458.08 PD 2004 PY 2004 AB Catalytic degradation of the mixture of polyethylene (PE), polypropylene (PP), and polystyrene (PS) was investigated in a semi-batch reactor. The main degradation product was liquid oil with gasoline range carbon number distributions. Clinoptilolite, a natural zeolite (HNZ) showed as good a catalytic performance as silica-alumina (SA). The protonated catalysts (HNZ, HZSM-5) showed an increased production of ethylbenzene, but a decrease of styrene production. Increase of degradation temperature resulted in a decrease of ethylbenzene and propylbenzene, but an increase of styrene. Thermogravimetric analysis revealed that the increased degradation rate in the mixed plastics came from the intermolecular carbenium ion transfer between the degraded fragments of PE, PP, and PS. TC 4 ZB 0 Z8 0 ZS 0 Z9 4 SN 0133-1736 UT WOS:000189353900010 ER PT J AU Katranas, TK Vlessidis, AG Tsiatouras, VA Triantafyllidis, KS Evmiridis, NP TI Dehydrogenation of propane over natural clinoptilolite zeolites SO MICROPOROUS AND MESOPOROUS MATERIALS VL 61 IS 1-3 BP 189 EP 198 DI 10.1016/S1387-1811(03)00367-6 PD JUL 18 2003 PY 2003 AB Clinoptilolite is one of the most commonly used natural zeolites in environmental and industrial applications. In this study, the activity and selectivity of two different clinoptilolite tuffs from Thrace region of Greece were investigated using the model reaction of propane dehydrogenation and were compared to those of synthetic proton and metal-modified ZSM-5 zeolite catalysts. The clinoptilolite bearing tuff from Metaxades (MCH) showed appreciable activity for propane dehydrogenation, similar to that of a steamed Cr-modified ZSM-5 zeolite and considerably higher compared to the second natural clinoptilolite tuff (SF) from the area of Pentalofos and to the H-ZSM-5 zeolite. The total propylene yield for the MCH sample at 540 degreesC was 8.4%, compared to 3.4% for SF, 5.3% for steamed H-ZSM-5 and 8.3% for steamed Cr-modified ZSM-5. The proton-exchanged forms of both natural zeolites showed improved conversion of propane but resulted in lower propylene selectivity due to subsequent hydrogen transfer, cracking and cyclo-oligomerization reactions induced by the higher number of framework Bronsted acid sites. (C) 2003 Elsevier Inc. All rights reserved. CT 6th International Conference on Occurrence, Properties and Utilization of Natural Zeolites CY JUN 03-07, 2002 CL ARISTOTLE UNIV, THESSALONIKI, GREECE HO ARISTOTLE UNIV SP Int Comm Nat Zeolites; Hellen Inst Geol & Mineral Explorat TC 20 ZB 0 Z8 3 ZS 0 Z9 22 SN 1387-1811 UT WOS:000184324100018 ER PT J AU Ozkan, F Gunduz, G Akpolat, O Besun, N Murzin, DY TI Isomerization of alpha-pinene over ion-exchanged natural zeolites SO CHEMICAL ENGINEERING JOURNAL VL 91 IS 2-3 BP 257 EP 269 AR PII S1385-8947(02)00162-6 DI 10.1016/S1385-8947(02)00162-6 PD MAR 15 2003 PY 2003 AB Catalysts prepared by ion exchange of clinoptilolite-based natural zeolite tuffs; with NH4+, Ba2+ and Pb2+ were investigated in the isomerization reaction of alpha-pinene at atmospheric pressure under nitrogen flow. Activity and selectivity to mono-, bi- and tricyclic products were correlated with acidity strength. (C) 2002 Elsevier Science B.V. All rights reserved. CT 15th International Conference on Chemical Reactor Modeling (CHEMREACTOR 15) CY JUN 05-08, 2001 CL HELSINKI, FINLAND RI Murzin, Dmitry/I-6285-2013 OI Murzin, Dmitry/0000-0003-0788-2643 TC 23 ZB 3 Z8 1 ZS 1 Z9 23 SN 1385-8947 UT WOS:000181148600022 ER PT J AU Rehakova, M Cuvanova, S Gaval'ova, Z Rimar, J TI Application of natural zeolite of the clinoptilolite type in agrochemistry and agriculture SO CHEMICKE LISTY VL 97 IS 5 BP 260 EP 264 PD 2003 PY 2003 AB Zeolites of the clinoptilolite type, as natural, inert and nontoxic materials, are widely applicable in the contemporary notion of ecological agriculture. Their structure is ideal for sorption and for ion exchange processes. Due to their structure and properties, the zeolites can be used as a slowly releasing carrier of agrochemicals, fertilizers, pharmaceutically and biochemically active compounds for veterinary pharmacy, including desinfectants. Natural zeolites can be also used for improving physical properties of soils and for treatment of contaminated soils. They are also suitable as additives to animal feed, where they enhance important body functions. TC 8 ZB 0 Z8 0 ZS 1 Z9 8 SN 0009-2770 UT WOS:000183228200004 ER PT S AU Yoon, JH Van, JH Kim, I Park, DW BE Anpo, M Onaka, M Yamashita, H TI Catalytic degradation of mixed plastics over natural clinoptilolite catalysts SO SCIENCE AND TECHNOLOGY IN CATALYSIS 2002 SE STUDIES IN SURFACE SCIENCE AND CATALYSIS VL 145 BP 467 EP 468 DI 10.1016/S0167-2991(03)80263-X PD 2003 PY 2003 CT 4th Tokyo Conference on Advanced Catalytic Science and Technology CY JUL 14-19, 2002 CL TOKYO, JAPAN SP Chem Soc Japan; Electrochem Soc Japan; Japan Assoc Zeolite; Japan Inst Energy; Japan Petr Inst; Japanese Photochem Assoc; Res Inst Innovat Technol Earth; Soc Chem Engineers; Soc Synthet Organ Chem; Surface Sci Soc Japan; Soc Polymer Sci TC 0 ZB 0 Z8 0 ZS 0 Z9 0 SN 0167-2991 BN 0-444-51349-3 UT WOS:000184716200106 ER PT J AU Lee, HC Woo, HC Chung, SH Kim, HJ Lee, KH Lee, JS TI Effects of metal cation on the skeletal isomerization of 1-butene over clinoptilolite SO JOURNAL OF CATALYSIS VL 211 IS 1 BP 216 EP 225 DI 10.1006/jcat.2002.3732 PD OCT 1 2002 PY 2002 AB Skeletal isomerization of I-butene to isobutene has been investigated over various metal-cation-exchanged natural clinoptilolite zeolites. The effects of metal cation exchange were examined by XRD, NH3-TPD, FT-IR, and solid-state NMR to elucidate the controlling factors affecting the selectivity to isobutene. Cobalt-cation-exchanged natural clinoptilolite zeolite (Co-HNZ) showed a higher selectivity to isobutene compared with that of HNZ at the same conversion of n-butenes under the same reaction conditions, while barium-cation-exchanged zeolite (Ba-HNZ) exhibited a higher activity but a very low selectivity to isobutene. It could be suggested that the high selectivity over the Co-HNZ catalyst was induced by selective removal of strong acid sites that were responsible for the side reactions of dimerization cracking as well as by imposing an effective constraint on zeolite channels. On the other hand, the high density and easy accessibility of acid sites mainly on the external surface in Ba-HNZ could increase the extent of the bilmolecular reaction pathway, leading to high yields of by-products. Thus, a selective catalyst for skeletal isomerization of 1-butene should satisfy multiple requirements regarding its acid site, namely, strength, type, concentration, and accessibility. (C) 2002 Elsevier Science (USA). TC 5 ZB 0 Z8 0 ZS 0 Z9 5 SN 0021-9517 UT WOS:000178377800023 ER PT J AU Lee, SY Yoon, JH Kim, JR Park, DW TI Degradation of polystyrene using clinoptilolite catalysts SO JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS VL 64 IS 1 BP 71 EP 83 AR PII S0165-2370(01)00171-1 DI 10.1016/S0165-2370(01)00171-1 PD JUL 2002 PY 2002 AB Several solid acids such as silica-alumina, HZSM-5, HY, mordenite and clinoptilolite (natural and synthesized) are screened for their performances in the catalytic degradation of polystyrene (PS). The clinoptilolites showed good catalytic activity for the degradation of PS with very high selectivity to aromatic liquids. The effects of catalyst acidity, reaction temperature and contact time on the distribution of aromatics are discussed. The increase of contact time and surface acidity enhanced the production of ethylbenzene. High degradation temperature favored the selectivity to styrene monomer. (C) 2002 Elsevier Science B.V. All rights reserved. TC 27 ZB 3 Z8 0 ZS 0 Z9 27 SN 0165-2370 UT WOS:000176268100006 ER PT J AU Long, RQ Yang, RT TI Selective catalytic reduction of NO with ammonia over Fe(3+)-exchanged mordenite (Fe-MOR): Catalytic performance, characterization, and mechanistic study SO JOURNAL OF CATALYSIS VL 207 IS 2 BP 274 EP 285 DI 10.1006/jcat.2002.3521 PD APR 25 2002 PY 2002 AB Fe-exchanged zeolites, i.e., mordenite (MOR), clinoptilolite (HEU), beta, ferrierite (FER), and chabazite (CHA), are studied as catalysts for selective catalytic reduction (SCR) of NO with NH(3). It is found that SCR activity decreases in the following order: Fe-MOR>Fe-HEU>Fe-FER>Fe-beta>Fe-CHA. Fe-MOR and Fe-HEU are much more
active than the commercial vanadia catalyst. For Fe-MOR, SCR activity
increases with a decreasing Si/Al ratio. Moreover, SO(2) and SO(2) +
H(2)O improve SCR activity. On Fe-MOR, nearly 100% NO conversion is
obtained at a high space velocity (GHSV = 4.6 x 10(5) h(-1)) in the
presence of SO(2). The Fe-MOR catalysts are also characterized by
H(2)-TPR (temperature-programmed reduction) and Fourier transform
infrared (FT-IR) spectroscopy. TPR profiles indicate that iron cations
in the catalysts are present as approximately 73% Fe(3+) and 27% Fe(2+).
FT-IR spectra show that NO can be oxidized by O(2) to N(2)O(3), NO(2),
and nitrate adsorbed species, and that they are bonded to the iron
cations. NH(3) molecules adsorb on Bronsted acid sites of the zeolite to
form NH(4)(+) ions. NO + O(2) is very active in reacting with NH(4)(+)
ions on Fe-MOR at 300degreesC, but it is less active with those on 4
H-MOR. This is in good agreement with their SCR activities and is
probably related to the fast formation of NO(2) on Fe-MOR. A possible
reaction scheme for SCR reduction is proposed. NO reduction involves the
reaction between NO(2) and a pair of NH(4)(+) ions to generate an active
intermediate, which then reacts with NO to produce N(2) and H(2)O. NO
oxidation to NO(2) is the rate-determining step. (C) 2002 Elsevier
Science (USA).
TC 47
ZB 3
Z8 6
ZS 0
Z9 52
SN 0021-9517
UT WOS:000175354900014
ER
PT J
AU Lee, SY
Yoon, JH
Park, DW
TI Catalytic degradation of mixture of polyethylene and polystyrene
SO JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
VL 8
IS 2
BP 143
EP 149
PD MAR 2002
PY 2002
AB The catalytic degradation of a mixture of polyethylene (PE) and
polystyrene (PS) was investigated in a semi-batch reactor. The influence
of the nature of the cracking catalyst and the reaction temperature was
also studied. The main degradation product was liquid oils with gasoline
range carbon number distributions. Natural clinoptilolite zeolite (HNZ)
exhibited an equivalent catalytic performance to silica-alumina (SA).
The HZSM-5 catalyst produced the highest amount of gaseous products. An
increase in the degradation temperature resulted in a decrease in
ethylbenzene and propylbenzene, but an increase in styrene. A
Thermogravimetric analysis revealed an interaction between PE and PS in
the catalytic degradation.
TC 6
ZB 0
Z8 0
ZS 0
Z9 6
SN 1226-086X
UT WOS:000174660000008
ER
PT J
AU Gates, WP
Anderson, JS
Raven, MD
Churchman, GJ
TI Mineralogy of a bentonite from Miles, Queensland, Australia and
characterisation of its acid activation products
SO APPLIED CLAY SCIENCE
VL 20
IS 4-5
BP 189
EP 197
DI 10.1016/S0169-1317(01)00072-2
PD JAN 2002
PY 2002
AB The mineralogy of a bentonite from Miles, Queensland, Australia, before
and after acid treatment (by reflux in 5.3 M HCl at 80 degreesC) has
been assessed by IR, XRD and chemical analysis. The < 2-mu m fraction of the Miles bentonite consists predominantly of a dioctahedral smectite (approximate to 69%), but which also contains significant amounts of quartz (approximate to 14%), feldspar (approximate to 8%), cristobalite/opal (approximate to 7%), as well as minor amounts (approximate to 1-2%) of clinoptilolite, mica/illite, gypsum and anatase, The smectite component is similar to that of Wyoming bentonite, having a cation exchange capacity of approximate to 103 cmol kg(-1). Prolonged acid treatment (24 h) led to a breakdown in the structure of this component, and caused a precipitation of hydrous silica phases. Structural decomposition was accomplished by a release into solution of octahedrally coordinated Mg (most readily), Fe and Al (least readily). There were also substantial losses to solution of Na and Ca. The precipitate of hydrous silica was enriched with time of acid treatment. A substantial amount of Al was retained within the solid reaction product, most likely as a constituent of impurities that were resistant to acid attack. Crown Copyright (C) 2002 Published by Elsevier Science B.V. All rights reserved. RI Raven, Mark/F-6918-2011 TC 59 ZB 6 Z8 3 ZS 1 Z9 61 SN 0169-1317 UT WOS:000173189500005 ER PT S AU Petranovskii, V Gurin, V Bogdanchikova, N Phatanasri, S Praserthdam, P BE Lakhtakia, A Dewar, G McCall, MW TI An effect of zeolite type upon properties of copper nanoparticles and clusters produced within them SO COMPLEX MEDIUMS III: BEYOND LINEAR ISOTROPIC DIELECTRICS SE Proceedings of SPIE-The International Society for Optical Engineering VL 4806 BP 233 EP 239 DI 10.1117/12.472988 PD 2002 PY 2002 AB Copper nanoparticles were produced within the protonated and alkaline forms of several zeolites (mordenite, erionite, clinoptilolite, and beta-zeolite) by the hydrogen reduction of corresponding Cu-exchanged forms. Variation of zeolite structure, reduction temperature and acidity of zeolites (regulated via cation types and Si/Al ratio) were the main factors influencing metal reducibility and appearance of copper reduced forms. They were detected by means of optical absorption using diffuse reflectance spectroscopy technique. The effect of zeolite type (with difference in nanopore size, acidity, ion-exchange capacity, etc.) upon the plasmon resonance band (lambda=550-600 nm) associated with the reduced copper clusters was investigated experimentally and discussed with the Mie theory simulation results. The type of this spectral appearance is associated with size of copper nanoparticles formed as the result of reduction and secondary aggregation and dielectric properties of zeolite microcrystals being a matrix for the nanoparticle stabilization. CT Conference on Complex Mediums III - Beyond Linear Isotropic Dielectrics CY JUL 08-10, 2002 CL SEATTLE, WA SP SPIE; Boeing Co; Pacific NW Natl Lab; Washington State Univ Coll Sci, Coll Engn & Architecture; Univ Washington, Coll Engn TC 2 ZB 0 Z8 0 ZS 0 Z9 2 SN 0277-786X BN 0-8194-4574-6 UT WOS:000177782700024 ER PT S AU Aliyev, AM Sarijanov, EE Savasci, OT Mikailov, RZ Shakhtakhtinsky, TN Sarioglan, A Poladly, PF Kuliyev, AR BE Aiello, R Giordano, G Testa, F TI Selection of an active zeolite catalyst and kinetics of vapor phase esterification of acetic acid with ethyl alcohol SO IMPACT OF ZEOLITES AND OTHER POROUS MATERIALS ON THE NEW TECHNOLOGIES AT THE BEGINNING OF THE NEW MILLENNIUM, PTS A AND B SE STUDIES IN SURFACE SCIENCE AND CATALYSIS VL 142 BP 787 EP 794 PN A&B PD 2002 PY 2002 AB Activity and selectivity of Azerbaijan natural clinoptilolite containing different amounts of zeolite (25.0, 44.0 and 89.0%); dealuminated and hydrogen forms of clinoptilolites prepared from Azerbaijan natural clinoptilolite containing 89.0% zeolite phase with silicate modulus chi=SiO2/Al2O3=8.6; Azerbaijan natural mordenite containing 75-80% zeolite phase with chi=9.6 and its hydrogen forms;, synthetic zeolites: NaY with chi=4.3 and its hydrogen forms - NaHY; the commercial beta zeolite with chi=25.0; the commercial zeolite HZSM-5 with chi=50.0 and HZSM-5 with chi=25.0 have been tested in vapor phase reaction of esterification of acetic acid with ethyl alcohol. On the basis of the kinetic investigations the efficient catalyst, beta zeolite with chi=25.0, has been selected for this reaction. It has been developed of the theoretical grounded kinetic model of the reaction on the catalyst, beta zeolite that satisfactorily describe of experimental data. According to this model ethyl acetate is formed on acidic sites of the catalyst at interaction of strongly absorbed molecules of acetic acid with weak absorbed molecules of ethyl alcohol. CT 2nd International Conference of the Federation-of-European-Zeolite-Associations CY SEP 01-05, 2002 CL TAORMINA, ITALY SP Italian Zeolite Assoc; Federat European Zeolite Assoc TC 0 ZB 0 Z8 0 ZS 0 Z9 0 SN 0167-2991 BN 0-444-51174-1 UT WOS:000181696400098 ER PT S AU Onyestyak, G Kallo, D BE Aiello, R Giordano, G Testa, F TI Catalytic behavior of Cd-clinoptilolite prepared by introduction of cadmium metal onto cationic sites SO IMPACT OF ZEOLITES AND OTHER POROUS MATERIALS ON THE NEW TECHNOLOGIES AT THE BEGINNING OF THE NEW MILLENNIUM, PTS A AND B SE STUDIES IN SURFACE SCIENCE AND CATALYSIS VL 142 BP 1047 EP 1054 PN A&B PD 2002 PY 2002 AB Cd-clinoptilolites were prepared using the conventional aqueous phase ion exchange procedure and by reacting a mixture of cadmium dust and NH4-clinoptilolite powder around 310degreesC, i.e., near to the melting point of the metal. The solid phase reaction was indicated by H-2 evolution and the decrease of XRD line intensities of cadmium metal. The NH3, leaving the cationic; sites was retarded to some extent by cadmium species. Higher degree of ion exchange was achieved using the solid phase reaction than by the conventional aqueous phase procedure. The catalytic activities of the preparations were compared in hydration of acetylene. The activities were tested in IR cell by reacting gas phase acetylene at 100degreesC with water adsorbed on the catalyst wafer resulting in formation of adsorbed acetaldehyde. The catalyst prepared by the aqueous phase Cd-exchange was more active, however, after treatment at 300degreesC, i.e., at temperature close to that of the solid phase reaction, its activity was essentially lower than that of the solid state preparation. CT 2nd International Conference of the Federation-of-European-Zeolite-Associations CY SEP 01-05, 2002 CL TAORMINA, ITALY SP Italian Zeolite Assoc; Federat European Zeolite Assoc TC 2 ZB 0 Z8 0 ZS 0 Z9 2 SN 0167-2991 BN 0-444-51174-1 UT WOS:000181696400131 ER PT S AU Petranovskii, V Gurin, V Bogdanchikova, N Hernandez, MA Avalos, M BE Sayari, A Jaroniec, M TI A selectivity of zeolite matrices in the Cu(II) reduction process SO NANOPOROUS MATERIALS III SE Studies in Surface Science and Catalysis VL 141 BP 561 EP 568 PD 2002 PY 2002 AB Copper nanoparticles were produced within a series of protonated and alkaline metal forms of zeolites (mordenite, erionite and clinoptilolite) by the hydrogen reduction of corresponding Cu(II)-exchanged forms. Variation of the zeolite structure, the reduction temperature and the acidity of zeolites (regulated via cation types and in the case of mordenite via Si/Al ratio from 5 to 103) are the main factors influencing the appearance of copper reduced forms. They were detected by means of optical absorption using Diffuse Reflectance Spectroscopy (DRS) technique as the plasmon resonance band of different shape and position and simulated with the Mie theory for the simple model of spherical copper particles embedded in a dielectric medium. The observed effects are interpreted as a difference in the acidity strength and type of matrix playing a role of medium for the reduction process. The acidity control and zeolite type structure are proposed as the main tools for selectivity of copper reduction and its final state. CT 3rd International Symposium on Nanoporous Materials CY JUN 12-15, 2002 CL OTTAWA, CANADA SP Univ Ottawa, Fac Sci; Natl Res Council Canada; Steacie Inst Molec Sci TC 2 ZB 0 Z8 0 ZS 1 Z9 3 SN 0167-2991 BN 0-444-51113-X UT WOS:000180926800071 ER PT J AU Kim, JR Yoon, JH Park, DW TI Catalytic recycling of the mixture of polypropylene and polystyrene SO POLYMER DEGRADATION AND STABILITY VL 76 IS 1 BP 61 EP 67 AR PII S0141-3910(01)00266-X DI 10.1016/S0141-3910(01)00266-X PD 2002 PY 2002 AB Catalytic degradation of the mixture of polypropylene (PP) and polystyrene (PS) was investigated in a semi-batch reactor. For all the catalysts HNZ, SA, HZSM-5) tested, the main degradation products were liquid oils with gasoline range carbon number distributions. A natural clinoptilolite zeolite (HNZ) showed as good catalytic performance as silica-alumina (SA). HZSM-5 catalyst produced the highest amount of gaseous products. Increase of degradation temperature resulted in a decrease of ethylbenzene and propylbenzene, but an increase of styrene. Thermogravimetric analysis revealed the interaction of PP and PS in the catalytic degradation. (C) 2002 Elsevier Science Ltd, All rights reserved. TC 17 ZB 0 Z8 3 ZS 0 Z9 20 SN 0141-3910 UT WOS:000174870300007 ER PT J AU Kim, JR Kim, YA Yoon, JH Park, DW Woo, HC TI Catalytic degradation of polypropylene: effect of dealumination of clinoptilolite catalyst SO POLYMER DEGRADATION AND STABILITY VL 75 IS 2 BP 287 EP 294 DI 10.1016/S0141-3910(01)00231-2 PD 2002 PY 2002 AB The performance of several differently treated clinoptilolite zeolites in the degradation of polypropylene was investigated in this study. The composition of degradation products, especially liquid fractions resulted over studied catalysts, was compared to understand the role of catalysts. The degradation was carried out in a semi-batch reactor with a mixture of polypropylene and catalysts at 400 degreesC. The liquid products from the catalytic degradation of polypropylene are distributed in a narrower range of carbon numbers compared with those obtained by thermal degradation. With dealuminated clinoptilolite catalysts, the distribution of liquid products shifted to lower numbers of carbon atoms due to the increase of the portion of medium acid sites and micropore diameter. The increase of temperature accelerated the cracking of intermediately degraded fragments to lower hydrocarbons. (C) 2002 Elsevier Science Ltd. All rights reserved. TC 18 ZB 1 Z8 1 ZS 0 Z9 18 SN 0141-3910 UT WOS:000173392700009 ER PT J AU Choo, H Hong, SB Kevan, L TI Comparative ESR and catalytic studies of ethylene dimerization on Pd(II)-exchanged clinoptilolite, mordenite, ferrierite, and SUZ-4 SO JOURNAL OF PHYSICAL CHEMISTRY B VL 105 IS 32 BP 7730 EP 7738 DI 10.1021/jp0108420 PD AUG 16 2001 PY 2001 AB Catalytic activity for ethylene dimerization is studied in four palladium-exchanged zeolites, PdH-clinoptilolite, PdH-mordenite, PdH-ferrierite, and PdHK-SUZ-4, with different channel systems. The formation and adsorbate interactions of NJ) are also investigated for a better understanding of the role of Pd(I) on the catalytic reaction in these zeolites using electron spin resonance (ESR) spectroscopy. Thermal and hydrogen reduction of Pd(II) in clinoptilolite, mordenite, ferrierite, and SUZ-4 produce isolated Pd(I) with somewhat different ESR parameters. The interaction of Pd(I) with various sizes of adsorbates shows some similarities in PdH-mordenite and PdH-ferrierite, indicating that Pd(I) is located in the main 12-ring and 10-ring channels of mordenite and ferrierite, respectively, where all the Pd(I) can coordinate with methanol and pyridine. However, SUZ-4 shows a noticeable difference in the way Pd(I) interacts with several adsorbates such as ammonia, methanol, and ethylene. These adsorbates reduce Pd(II) to Pd(I) at 298 K, leading to the formation of two Pd(I) ions situated at two different sites of SUZ-4. One is the same Pd(I) ion site formed by thermal reduction but it appears at higher intensity upon adsorption. The other Pd(I) is an isolated Pd(I) produced only after prolonged annealing with adsorbates. Our ESR and catalytic results show that Pd(I) is active for ethylene dimerization in these four channel-type zeolites. This activity is dependent on the location and accessibility of Pd(I) and the reaction temperature. All catalysts deactivate due to the further reduction of Pd(I) by ethylene and butene. Analysis of the composition of butene products indicates that PdH-clinoptilolite and PdHK-SUZ-4 reach a thermal equilibrium distribution faster than do PdH-mordenite and PdH-ferrierite. TC 14 ZB 2 Z8 0 ZS 0 Z9 14 SN 1089-5647 UT WOS:000170494000018 ER PT J AU Long, RQ Yang, RT TI Selective catalytic oxidation (SCO) of ammonia to nitrogen over Fe-exchanged zeolites SO JOURNAL OF CATALYSIS VL 201 IS 1 BP 145 EP 152 DI 10.1006/jcat.2001.3234 PD JUL 1 2001 PY 2001 AB Fe-exchanged zeolites were prepared and studied as catalysts for selective catalytic oxidation (SCO) of ammonia to nitrogen in the presence of excess oxygen. Fe-ZSM-5, Fe-mordenite (MOR), and Fe-clinoptilolite (HEU) showed excellent SCO performance at a very high space velocity (GHSV = 2.3 x 10(5) h(-1)). Greater than 97% NH3 conversion and nearly 100% N-2 selectivity were obtained. Among different zeolites, the catalytic performance decreased in the sequence of Fe-ZSM-5, Fe-MOR, Fe-HEU > Fe-Y, Fe-Beta > Fe-ferrierite,
Fe-chabazite. High iron content, low Si/Al ratio, and low ammonia
concentration were favorable for high activities for NH3 oxidation to
N-2. For the Fe-exchanged zeolites, there existed a good correlation
between the N-2 selectivity for the SCO reaction and the activity for
the SCR (selective catalytic reduction) of NO with ammonia; i.e., the
higher the SCR activity, the higher the N-2 selectivity in SCO. The
variable valence of iron cations might be beneficial to oxygen
activation and thus result in the high SCO performance for the
Fe-exchanged zeolites. A kinetic study indicated that the reaction was
first order with respect to NH3 and the apparent reaction activation
energy (E-a) was 88 kJ/mol. (C) 2001 Academic Press
TC 62
ZB 0
Z8 1
ZS 0
Z9 62
SN 0021-9517
UT WOS:000169706300015
ER
PT J
AU Patrylaka, KI
Bobonych, FM
Voloshyna, YG
Levchuk, MM
Solomakha, VM
Patrylak, LK
Manza, IA
Taranookha, OM
TI Linear hexane isomerization over the natural zeolite based catalysts
depending on the zeolite phase composition
SO CATALYSIS TODAY
VL 65
IS 2-4
BP 129
EP 135
DI 10.1016/S0920-5861(00)00573-3
PD FEB 20 2001
PY 2001
AB A range of Pd-containing catalysts on the basis of
mordenite-clinoptilolite rocks of different starting phase compositions
is synthesized. Final phase composition and acidity of rocks change as
the conditions of their dealumination are changed. The efficiency of
catalysts synthesized is weakly influenced by change of mordenite
component contents within 50-80%, and it is not inferior to the
efficiency of the catalysts on the synthetic mordenite basis. The nature
of active sites as trifunction ones and isomerization mechanism are
proposed, (C) 2001 Elsevier Science B.V. All rights reserved.
CT 4th European Congress on Catalysis (EUROPACAT-IV)
CY SEP 05-10, 1999
CL RIMINI, ITALY
TC 14
ZB 0
Z8 0
ZS 0
Z9 14
SN 0920-5861
UT WOS:000167824900006
ER
PT J
AU Kallo, D
Onyestyak, G
TI Acetylene-hydration kinetics on cadmium-exchanged clinoptilolite
catalyst
SO HELVETICA CHIMICA ACTA
VL 84
IS 5
BP 1157
EP 1162
DI 10.1002/1522-2675(20010516)84:5<1157::aid-hlca1157>3.0.CO;2-7
PD 2001
PY 2001
AB Hydration of acetylene under steady-state conditions around 450 K
proceeds on Cd-clinoptilolite without catalyst deactivation and
formation of by-products. Reaction rates were determined under
steady-state conditions at different partial pressures of acetylene,
water, and acetaldehyde. In relation with the results, rate equations
for different kinetic models were evaluated. Langmuir-Hinshelwood
kinetics was established. According to this model, acetylene and water
must adsorb on similar sires, and the surface reaction between the
adsorbed reactants is the rate-determining step, which is followed by
equilibrated desorption of the produced acetaldehyde.
TC 6
ZB 0
Z8 0
ZS 0
Z9 6
SN 0018-019X
UT WOS:000169051800011
ER
PT J
AU Meshkova, IN
Ushakova, TM
Gul'tseva, NM
Ladygina, TA
Kovaleva, NY
Novokshonova, LA
TI Polymerization of ethylene over zeolite-supported catalysts
SO POLIMERY
VL 46
IS 7-8
BP 529
EP 533
PD 2001
PY 2001
AB Zeolites including Na-form ZSM-5 (Si/Al = 42) and natural zeolite
(Shivyrtuisk deposit: clinoptilolite 60 +/- 6%, water 14.2%) were
studied as supports for olefin polymerization organometallic catalysts.
Zeolite-fixed aluminoxanes, viz., anchored to the surface of the
support, were prepared by partially hydrolyzing alkylaluminums (AlMe3
AlEt2Cl) with zeolite's internal water. Thus modified, the zeolites were
made to react with transition metal compounds like Cp2ZrCl2 or VOCl3.
The product of the reaction of zeolites' internae water with AlMe3 was
made to react with Cp2ZrCl2, and the resulting product was found to be
active in the polymerization of ethylene with no additional activation
carried out with MAO. In this way, an active metallocene catalyst was
prepared without the use of MAO. Yet, when added as cocatalyst, MAO
still activated the system, unlike the other conventional organoaluminum
cocatalysts. The PE produced over the ZSM-5 (H2O)/AlMe3/CP2ZrCl2 system
had a higher M and a higher melting point than PE prepared over a
homogeneous CP2ZrCl2 + MAO catalyst system.
CT 7th Seminar on Organometallic Complex as Catalysts of Vinyl Compound
Polymerization
CY SEP 12-17, 1999
CL TURAWA, POLAND
TC 2
ZB 0
Z8 0
ZS 0
Z9 2
SN 0032-2725
UT WOS:000170189300011
ER
PT J
AU Lee, SY
Yoon, JH
Kim, JR
Park, DW
TI Catalytic degradation of polystyrene over natural clinoptilolite zeolite
SO POLYMER DEGRADATION AND STABILITY
VL 74
IS 2
BP 297
EP 305
DI 10.1016/S0141-3910(01)00162-8
PD 2001
PY 2001
AB Natural clinoptilolite zeolite HNZ has been studied as a catalyst in the
degradation of polystyrene (PS) at 400 degreesC. Its performance on the
degradation was compared with HZSM-5, silica-alumina, and also with
thermal degradation. HNZ was as effective as HZSM-5 for the production
of liquid oils with carbon numbers of C-5-C-12, without any severe
deactivation. The main product of PS degradation was styrene for both
thermal and catalytic degradation. Among the catalysts tested,
silica-alumina showed the highest yield of ethylbenzene and the lowest
one of styrene due to its mesopores. Increase in degradation temperature
for HNZ resulted in a decrease of selectivity towards ethylbenzene and
propylbenzene, but an increase of styrene selectivity with lower yield
of styrene dimers. A kinetic analysis by thermogravimetric analysis was
also carried out using a dynamic model. It offered reliable kinetic
parameters for the catalytic degradation of PS over HNZ. The apparent
activation energy was found to be 360 kJ/mol, and the catalytic
degradation of PS followed first-order kinetics. (C) 2001 Elsevier
Science Ltd. All rights reserved.
TC 31
ZB 3
Z8 4
ZS 1
Z9 36
SN 0141-3910
UT WOS:000172112600012
ER
PT J
AU Linares, CF
Goldwasser, MR
Machado, FJ
Rivera, A
Rodriguez-Fuentes, G
Barrault, J
TI Advantages of base exchanged natural clinoptilolite as a catalyst for
the Knoevenagel reaction
SO MICROPOROUS AND MESOPOROUS MATERIALS
VL 41
IS 1-3
BP 69
EP 77
DI 10.1016/S1387-1811(00)00274-2
PD DEC 2000
PY 2000
AB The potential use of natural zeolites as base catalysts was ascertained
by studying the catalytic behavior of a purified natural clinoptilolite
(NZ) and its sodium carbonate modified form (NZC) in the aldol
condensation reaction of benzaldehyde with methyl cyanoacetate
(Knoevenagel reaction). The natural zeolites activities were compared to
that of cesium modified X and Y faujasite type zeolites (CsFAUX and
CsFAUY). It was observed that the activity of the NZC zeolite was five
times higher than that of NZ. The normalized activity per surface area
of the modified clinoptilolites was higher than that shown by synthetic
FAUs zeolites. The higher activity of NZC is attributed to the presence
of single and double carbonate species, such as Na2CO3 and
Na2Ca(CO3)(2), occluded in the internal cavities of the clinoptilolite
zeolite, as confirmed by XRD and IR diffuse reflectance. The CO2 and NH3
TPD analysis corroborated the presence of stronger basic sites in the
natural zeolites in good agreement with the catalytic behavior shown by
these solids in the Knoevenagel condensation reaction. (C) 2000 Elsevier
Science B.V. All rights reserved.
TC 15
ZB 2
Z8 2
ZS 1
Z9 16
SN 1387-1811
UT WOS:000165701600005
ER
PT J
AU Sobokhoeva, TS
Latysheva, LE
Skornikova, SA
Lunina, EV
Kuz'mina, EV
Shmidt, FK
TI Comparative characteristics of clinoptilolite from eastern Siberia and
Georgia and catalysts on their base
SO RUSSIAN JOURNAL OF APPLIED CHEMISTRY
VL 73
IS 12
BP 2052
EP 2056
PD DEC 2000
PY 2000
AB Adsorption, structural, and catalytic properties of natural
clinoptilolites from various deposits of Georgia and eastern Siberia was
studied together with the catalytic activity of clinoptilolite-based
catalysts in isomerization of m-xylene.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1070-4272
UT WOS:000169540600011
ER
PT J
AU Allahverdiev, AI
Irandoust, S
Andersson, B
Murzin, DY
TI Kinetics of alpha-pinene enantiomeric isomerization over clinoptilolite
SO APPLIED CATALYSIS A-GENERAL
VL 198
IS 1-2
BP 197
EP 206
DI 10.1016/S0926-860X(99)00511-6
PD MAY 15 2000
PY 2000
AB Kinetics of the liquid-phase isomerization of enantioisomers of
alpha-pinene using natural clinoptilolite was investigated. The
experimental ranges of temperature and pressure (N-2) Were T= 120-160
degrees C and P = 1-10 bars, respectively. Initially, mainly camphene
and limonene were produced; the ratio of enantiomers corresponded to the
ratio of +/- isomers in alpha-pinene. At relatively high conversions
other monocyclic (terpinene and terpinolene) and tricyclic products
(tricyclene) were formed. A kinetic model is developed which described
the experimental data well. (C) 2000 Elsevier Science B.V. All rights
reserved.
RI Murzin, Dmitry/I-6285-2013
OI Murzin, Dmitry/0000-0003-0788-2643
TC 15
ZB 0
Z8 0
ZS 0
Z9 15
SN 0926-860X
UT WOS:000086809600018
ER
PT J
AU Lee, HC
Woo, HC
Ryoo, R
Lee, KH
Lee, JS
TI Skeletal isomerization of n-butenes to isobutene over acid-treated
natural clinoptilolite zeolites
SO APPLIED CATALYSIS A-GENERAL
VL 196
IS 1
BP 135
EP 142
DI 10.1016/S0926-860X(99)00458-5
PD MAR 27 2000
PY 2000
AB The proton form of the natural clinoptilolite zeolite (HNZ) was modified
by treatment with various acids. Effects of modification on catalytic
performance were investigated for the skeletal isomerization of
n-butenes to isobutene. Among HNZs treated with various acids, only
those modified with boric acid (B-HNZ) showed an improved catalytic
performance of skeletal isomerization in terms of activity and
stability. Furthermore, B-HNZ exhibited higher isobutene selectivity
compared to unmodified HNZ at the same conversion of n-butenes. The
performance was comparable to that of a widely known ferrierite catalyst
at the same reaction conditions. The main effect of boric acid treatment
on HNZ was the selective increase in the number of acid sites of
moderate strength required for efficient catalysts in skeletal
isomerization without collapse of its framework. These acid sites of
moderate strength were considered to be selective and stable reaction
sites for skeletal isomerization of n-butenes. Coke deposition poisoned
non-selective strong acid sites and imposed a spatial restriction on
zeolite channels, leading to suppression of undesired dimerization
reactions. Factors affecting selectivity to isobutene an discussed. (C)
2000 Elsevier Science B.V. All rights reserved.
RI Ryoo, Ryong /B-1090-2009
TC 13
ZB 1
Z8 0
ZS 0
Z9 13
SN 0926-860X
UT WOS:000085823200014
ER
PT J
AU Seo, G
Kim, MY
Kim, JH
TI IR study on the reaction path of skeletal isomerization of 1-butene
SO CATALYSIS LETTERS
VL 67
IS 2-4
BP 207
EP 213
DI 10.1023/A:1019081925202
PD 2000
PY 2000
AB The reaction molecularity of the skeletal isomerization on zeolite was
deduced from IR spectra of adsorbed butene recorded with heating.
Formation of polymeric species from adsorbed butene was observed on
ZSM-5 and beta zeolites, non-selective catalysts for isobutene
production. On the other hand, most of butene molecules adsorbed on
ferrierite and clinoptilolite behaved monomolecularly, resulting in
complete desorption even at ambient temperature. The exceptional
selectivity for isobutene of ferrierite and clinoptilolite was ascribed
to the sparse distribution of adsorbed butene molecules, suppressing
bimolecular oligomerization and enhancing monomolecular skeletal
isomerization.
TC 9
ZB 0
Z8 0
ZS 0
Z9 9
SN 1011-372X
UT WOS:000088347900021
ER
PT J
AU Patrilyak, KI
Bobonich, FM
Voloshina, YG
Levchuk, NN
Solomakha, VN
Yakovenko, AN
Manza, IA
Tsuprik, IN
TI Hexane isomerization on catalysts with natural mordenite-clinoptilolite
base of different phase composition
SO RUSSIAN JOURNAL OF APPLIED CHEMISTRY
VL 72
IS 11
BP 1946
EP 1951
PD NOV 1999
PY 1999
AB n-Hexane isomerization on palladium-containing catalysts based on
modernite-clinoptilolite rocks of different phase composition was
studied, The catalysts were decationized on heating and dealuminized by
acid treatment.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1070-4272
UT WOS:000086396300017
ER
PT J
AU Ruiz-Salvador, AR
Gomez, A
Lewis, DW
Rodriguez-Fuentes, G
Montero, L
TI Silicon-aluminium distribution in dehydrated calcium heulandite
SO PHYSICAL CHEMISTRY CHEMICAL PHYSICS
VL 1
IS 7
BP 1679
EP 1685
PD APR 1 1999
PY 1999
AB The distribution of aluminium within the lattice of a model calcium
heulandite is considered. Significant segregation of Al to particular
sites is noted with T2 being preferentially occupied whereas T4 has a
low Al occupancy. T5 is also occupied, in contrast to earlier work on
Na-clinoptilolite. The resulting distributions are also significantly
different to previous work on Na-clinoptilolite, demonstrating the
influence of the Si/Al ratio and cation species on the spatial
arrangement of Si and Al in the framework.
RI Lewis, Dewi/C-1536-2008
TC 16
ZB 0
Z8 0
ZS 0
Z9 16
SN 1463-9076
UT WOS:000079597400038
ER
PT J
AU Sobokhoeva, TS
Latysheva, LE
Skornikova, SA
Nikiforova, IN
Chukin, GD
Mil'man, FA
TI Catalysts for isomerization of aromatic hydrocarbons based on natural
zeolites from the Baikal region
SO RUSSIAN JOURNAL OF APPLIED CHEMISTRY
VL 72
IS 3
BP 457
EP 461
PD MAR 1999
PY 1999
AB A method is proposed for preparing a catalyst for isomerization of
C-7-C-9 aromatic hydrocarbons, based on natural zeolites and containing
no noble metals. The adsorption and acidic characteristics of catalysts
based on clinoptilolite and chabazite were studied by X-ray
photoelectron and IR spectroscopy and by gas-liquid chromatography.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1070-4272
UT WOS:000081268700020
ER
PT J
AU Kim, YG
Kim, YC
Hong, SB
Kim, MH
Kim, YP
Uh, YS
TI Selective reduction of nitric oxide by methane on cobalt-ion-exchanged
synthetic clinoptilolite zeolite in oxygen-rich atmosphere
SO CATALYSIS LETTERS
VL 57
IS 4
BP 179
EP 185
DI 10.1023/A:1019032623674
PD 1999
PY 1999
AB Selective reduction of NO by CH4 in the presence of excess O-2 has been
studied on cobalt-ion-exchanged synthetic clinoptilolite (Co-CLI)
zeolite. The catalytic results are compared with those obtained from
Co-ZSM-5 and Co-FER, the two most widely studied catalysts for this
reaction. At T greater than or equal to 500 degrees C, Co-CLI is much
more active for NO reduction than Co-ZSM-5, but it is less active than
Co-FER. However, it is found that the selectivity for CH4 toward
reacting with NO at high temperatures (T greater than or equal to 450
degrees C) is higher on Co-CLI than on Co-ZSM-5 or Co-FER. On the basic
of the overall catalytic results, the importance of zeolite pore size as
a structural parameter influencing the activity of intrazeolitic Co2+
ions for NO reduction by CH4 is discussed.
TC 8
ZB 0
Z8 1
ZS 0
Z9 9
SN 1011-372X
UT WOS:000079584500004
ER
PT J
AU Park, DW
Hwang, EY
Kim, JR
Choi, JK
Kim, YA
Woo, HC
TI Catalytic degradation of polyethylene over solid acid catalysts
SO POLYMER DEGRADATION AND STABILITY
VL 65
IS 2
BP 193
EP 198
DI 10.1016/S0141-3910(99)00004-X
PD 1999
PY 1999
AB In this study we investigated the catalytic degradation of polyethylene
(PE) in a fixed-bed reactor composed of a melter and a catalytic
cracking bed. Solid acid catalysts, silica-alumina and zeolites [HZSM-5,
natural zeolite (NZ), Y zeolite, etc.] were screened for polyethylene
degradation in the range of 450-500 degrees C. The degradation products
of PE, especially a liquid fraction, formed over solid acid catalysts,
were analyzed by gas chromatography-mass spectroscopy (GC-MS). Compared
with those obtained by thermal degradation, the catalytic degradation
products are distributed in a narrow range of carbon numbers. The liquid
fraction contained large amounts of iso-paraffins and aromatics, as are
present in the gasoline fraction of petroleum. The NZ catalyst
(clinoptilolite structure, occurring in the Youngil area of Korea) aias
an efficient catalyst for the PE degradation. The acidity and
characteristic pore structure of zeolites appear to be responsible for
the good performance. The effects of temperature, contact time, and the
presence of nickel metal on the product distribution in PE degradation
are also discussed in this work. (C) 1999 Elsevier Science Ltd. All
rights reserved.
TC 63
ZB 3
Z8 2
ZS 1
Z9 65
SN 0141-3910
UT WOS:000081358700004
ER
PT S
AU Colella, C
BE Kiricsi, I
PalBorbely, G
Nagy, JB
Karge, HG
TI Natural zeolites in environmentally friendly processes and applications
SO POROUS MATERIALS IN ENVIRONMENTALLY FRIENDLY PROCESSES
SE STUDIES IN SURFACE SCIENCE AND CATALYSIS
VL 125
BP 641
EP 655
PD 1999
PY 1999
AB An outline of the occurrences, features and environmental uses of the
main sedimentary zeolites, namely chabazite, clinoptilolite, mordenite
and phillipsite, is presented. After pointing out that zeolite-bearing
rocks should not be considered as substitutes for synthetic zeolites, as
they are lacking of purity and constancy of composition, three major
areas of environmental application are identified: soil amendment,
cement manufacture and wastewater purification. Present and perspective
utilizations in these areas are dealt with and discussed, giving also a
few information on the use of natural zeolites as adsorbents and
catalysts.
CT 1st International FEZA Conference
CY SEP 01-04, 1999
CL EGER, HUNGARY
SP Federat European Zeolite Assoc
TC 44
ZB 13
Z8 1
ZS 0
Z9 45
SN 0167-2991
BN 0-444-50244-0
UT WOS:000084209700081
ER
PT J
AU Patrylak, KI
Bobonych, FM
Voloshyna, YG
Levchuk, MM
Il'in, VG
Yakovenko, OM
Manza, IA
Tsupryk, IM
TI Ukrainian mordenite-clinoptilolite rocks as a base for linear hexane
isomerization catalyst
SO APPLIED CATALYSIS A-GENERAL
VL 174
IS 1-2
BP 187
EP 198
DI 10.1016/S0926-860X(98)00196-3
PD NOV 16 1998
PY 1998
AB The ways of preparation of the linear hexane hydroisomerization
catalysts on the base of mordenite-clinoptilolite rocks of Ukrainian
deposits are described: under the strictly defined conditions of thermic
and acidic treatments of parent rocks, followed by palladium (0.5 wt%)
introduction, the samples of catalysts were synthesized which are well
comparable with the catalysts on the base of synthetic mordenite. The
high efficiency of the samples synthesized was achieved due to the
appropriate degrees of the residual crystallinity of the
mordenite-clinoptilolite rocks modified as well as due to the
corresponding strong acidic sites content of their zeolitic components.
The isomerization mechanism through the hexane molecules protonation
resulting in the formation of non-classic carbonium ions, which include
the pentacoordinated carbon atoms, with subsequent dehydrogenation of
these structures over Lewis acidic sites is proposed - the role of Lewis
acids play probably palladium and extraframework aluminum. Based on the
consideration of the different proton affinity of various C6H14 isomers,
the plausible pathways to the formation of definite hexane isomers are
discussed. These routes give such sets of individual branched hexanes
which consist both the thermodynamically predicted and really found
isomerizate compositions. (C) 1998 Elsevier Science B.V. All rights
reserved.
TC 13
ZB 0
Z8 0
ZS 0
Z9 13
SN 0926-860X
UT WOS:000077348300020
ER
PT J
AU Mishima, H
Hashmoto, K
Ono, T
Anpo, M
TI Selective catalytic reduction of NO with NH3 over natural zeolites and
its application to stationary diesel engine exhaust
SO APPLIED CATALYSIS B-ENVIRONMENTAL
VL 19
IS 2
BP 119
EP 126
DI 10.1016/S0926-3373(98)00071-X
PD NOV 9 1998
PY 1998
AB Cation exchanged natural zeolite catalysts for the reduction of NO with
NH3 were developed. The synthetic mordenite containing Cu, V, and Cr
cations showed high activity for the reduction of NO with NH3. Natural
Izulralite containing mainly mordenite exhibits high activity for the
selective reduction of NO when they were anchored with Cu, Mn, Co, and V
cations. Furthermore, the anchored pellet catalysts prepared from Zeo 3S
(clinoptilolite) and Izukalite exchanged with vanadium ions and mixed
with TiO2 exhibited high activity for the reduction of NO with NH3. The
honeycomb catalysts prepared from V-Izukalite were found to be
especially effective for stationary diesel engine exhaust. (C) 1998
Elsevier Science B.V. All rights reserved.
RI Anpo, Masakazu/B-2036-2010
TC 24
ZB 1
Z8 2
ZS 0
Z9 26
SN 0926-3373
UT WOS:000077686800005
ER
PT J
AU Hwang, EY
Choi, JK
Kim, DH
Park, DW
Woo, HC
TI Catalytic degradation of polypropylene I. Screening of catalysts
SO KOREAN JOURNAL OF CHEMICAL ENGINEERING
VL 15
IS 4
BP 434
EP 438
DI 10.1007/BF02697135
PD JUL 1998
PY 1998
AB The catalytic degradation of polypropylene has been investigated in this
study. Solid acid catalysts, such as silica-alumina and zeolites
(HZSM-5, natural zeolite, Mordenite etc.), were screened for
polypropylene degradation in the range of 350-450 degrees C. The
degradation products of polypropylene, especially a liquid fraction,
formed over solid acid catalysts, were analyzed by GC/MS. The
degradation products are distributed in a narrow range of carbon number
compared with those obtained by thermal degradation. The liquid fraction
contained large amounts of iso-paraffins and aromatics as are present in
the gasoline fraction of petroleum. The natural zeolite catalyst
(clinoptilolite structure, occurring in Youngil area of Korea) was an
efficient catalyst for the polypropylene degradation. The acidity and
characteristic pore structure of this zeolite appear to be responsible
for the good performance. The effects of temperature and reaction time
on the product distribution have also been studied in this work.
TC 22
ZB 1
Z8 1
ZS 0
Z9 23
SN 0256-1115
UT WOS:000075340300012
ER
PT J
AU Baranovskaya, OE
Zinenko, OG
Zhiznevskii, VM
Tokarev, VS
Shafranskaya, ET
TI Activity of catalysts in production of methyl tert-butyl ether
SO RUSSIAN JOURNAL OF APPLIED CHEMISTRY
VL 71
IS 7
BP 1193
EP 1196
PD JUL 1998
PY 1998
AB High-silicon synthetic and natural (clinoptilolite) zeolites, carbon
fibrous sulfonic cation exchanger, and aluminosilicate catalyst were
first tested as catalysts for production of methyl tert-butyl ether.
Their physicochemical properties (surface acidity and chemisorption of
isobutylene and methanol) were studied.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1070-4272
UT WOS:000077366100021
ER
PT J
AU Allahverdiev, AI
Gunduz, G
Murzin, DY
TI Kinetics of alpha-pinene isomerization
SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
VL 37
IS 6
BP 2373
EP 2377
DI 10.1021/ie970573t
PD JUN 1998
PY 1998
AB The kinetics of pinene isomerization over clinoptilolite with formation
of several products has been investigated in a batch reactor at
atmospheric pressure. Initially mainly camphene and limonene were
produced, and only at relatively high conversions were other secondary
products formed. Selectivity values at particular conversions were seen
to be independent of catalyst pretreatment, although activity was
different. The observed kinetic regularities were modeled on the basis
of an elementary step mechanism.
RI Murzin, Dmitry/I-6285-2013
OI Murzin, Dmitry/0000-0003-0788-2643
TC 37
ZB 4
Z8 0
ZS 0
Z9 37
SN 0888-5885
UT WOS:000074075600041
ER
PT S
AU Schay, Z
Kiricsi, I
Guczi, L
BE Kruse, N
Frennet, A
Bastin, JM
TI Transient kinetic study on NO decomposition over Cu-ZSM-5 catalysts
SO CATALYSIS AND AUTOMOTIVE POLLUTION CONTROL IV
SE STUDIES IN SURFACE SCIENCE AND CATALYSIS
VL 116
BP 347
EP 355
PD 1998
PY 1998
AB Decomposition of NO was studied on Cu-clinoptilolite and Cu-ZSM-5
zeolites of different Si/Al ratio and copper ion exchange rate. During
the first contact at 600 degrees C with NO an irreversible oxygen uptake
by the catalysts was observed. On the long pulse of the NO concentration
in the transient stage carried out under isothermal condition,
overshoots in N-2 and O-2 concentration were observed at the leading and
falling edge, respectively. In the TPD experiments after NO adsorption a
surface complex formulated as NO3 is decomposed at about the reaction
temperature into equimolar amounts of NO and O-2. The role of the
surface complex in the NO decomposition is discussed.
CT 4th International Symposium on Catalysis and Automotive Pollution
Control (CAPoC4)
CY APR 09-11, 1997
CL BRUSSELS, BELGIUM
SP AlliedSignal Inc; Automobile Emiss Control Catalyst; Degussa AG;
Engelhard Co; Ford Motor Co; Johnson Matthey Ltd; Rhone Poulenc Terres
Rares Gallium; Shell
TC 7
ZB 0
Z8 0
ZS 0
Z9 7
SN 0167-2991
BN 0-444-82795-1
UT WOS:000074776800033
ER
PT J
AU Seo, G
Kim, MW
Kim, JH
Ahn, BJ
Hong, SB
Uh, YS
TI Skeletal isomerization of 1-butene on synthetic clinoptilolite zeolite
SO CATALYSIS LETTERS
VL 55
IS 2
BP 105
EP 112
DI 10.1023/A:1019070526033
PD 1998
PY 1998
AB A pure, highly crystalline clinoptilolite (CLI) zeolite with a Si/Al
ratio of 5.8 has been synthesized using a small amount (1%) of seed
crystals and tested as a catalyst for the skeletal isomerization of
I-butene at 623-723 K at atmospheric pressure. The catalytic results are
compared to those obtained from a ferrierite (FER) zeolite with a Si/Al
ratio of 7.6. It is found that selectivity for isobutene is very high on
CLI zeolite, but conversion was lower than for FER zeolite. The
simulated distribution and calculated potential profile of I-butene
molecules in CLI zeolite pore 10-ring channels show that the spatial
constraints imposed by the pores are very severe. The exceptional
selectivity and the low conversion of CLI zeolite results from the
strict restriction of adsorption to very specific sites, inhibiting
dimerization, as well as from the high potential barrier which reduces
mass transfer.
TC 15
ZB 0
Z8 0
ZS 0
Z9 15
SN 1011-372X
UT WOS:000076952800009
ER
PT S
AU Guczi, L
Borko, L
Schay, Z
BE Rao, TSR
Dhar, GM
TI Some problems on environmental catalysis
SO RECENT ADVANCES IN BASIC AND APPLIED ASPECTS OF INDUSTRIAL CATALYSIS
SE STUDIES IN SURFACE SCIENCE AND CATALYSIS
VL 113
BP 69
EP 80
PD 1998
PY 1998
AB In order to optimise the catalytic processes involving NO, abatement and
total combustion of volatile organic compounds (VOC), it is prerequisite
to elucidate the mechanism of these processes. In the lecture three
processes will be discussed.
Atomic level approach will be applied to study NO+NH3 reaction on Pt
foil to form N-2 and H2O. The reaction is accelerated by adding trace
amount of oxygen. In certain pressure and temperature range an
oscillation commences. The problem is discussed in terms of the special
composition of the surface species.
The NO decomposition was studied over Cu-ZSM-5 catalysts prepared by ion
exchange and solid state exchange methods. Transient kinetic studies and
FTIR measurements indicated the presence of excess oxygen on the surface
which is involved in the formation of Cu2+(O)(NO)(NO2) species. These
intermediates play a key role in the NO decomposition.
Total combustion of In-xylene was studied over palladium catalysts in
various forms (amorphous alloys, deposited over clinoptilolite and over
stainless steel flakes). Low/high activity states were observed due to
the different oxidation states of palladium measured by XPS method.
Homogeneous chain reaction initiated by the catalyst surface was found
to be responsible for the high activity state and involvement of the
surface carbon was the key issue in the self-sustained and damped
oscillations.
CT 13th National Symposium and Silver Jubilee Symposium of Catalysis of
India
CY APR 02-04, 1997
CL DEHRA DUN, INDIA
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 0167-2991
BN 0-444-82920-2
UT WOS:000073803300005
ER
PT J
AU Findik, S
Gunduz, G
TI Isomerization of alpha-pinene to camphene
SO JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY
VL 74
IS 9
BP 1145
EP 1151
DI 10.1007/s11746-997-0038-8
PD SEP 1997
PY 1997
AB The catalytic isomerization reaction of cr-pinene to camphene over a
clinoptilolite catalyst was investigated in a batch reactor open to the
atmosphere between 130 and 155 degrees C. The catalyst was selective to
the isomerization of alpha-pinene to camphene. The effects of several
variables, such as reaction temperature, amount of catalyst, stirring
speed and catalyst particle size, on the conversion of alpha-pinene and
selectivity to camphene were determined. The reaction fits a first-order
parallel reaction with rate constants of k(1) = 3.020.10(-2)
e(-33381.6/RT) for the production of camphene and of k(2) = 1.576.10(-2)
e(-31096.53/RT) for the production of limonene.
TC 31
ZB 5
Z8 1
ZS 2
Z9 32
SN 0003-021X
UT WOS:A1997XW32600018
ER
PT J
AU Zhao, DY
Szostak, R
Kevan, L
TI Electron spin resonance and electron spin echo modulation spectroscopic
studies of cupric ion-adsorbate interactions in synthetic clinoptilolite
SO JOURNAL OF PHYSICAL CHEMISTRY B
VL 101
IS 27
BP 5382
EP 5390
DI 10.1021/jp970700z
PD JUL 3 1997
PY 1997
AB The site locations and adsorbate interactions of Cu2+ in Cu2+-exchanged
synthetic clinoptilolite have been determined by electron spin resonance
and electron spin echo modulation spectroscopies. Strong effects of the
H+ Li+, Na+, and K+ cocations have been found on the coordination number
and on the location of the cupric ion. Cu2+ coordinates three molecules
of water in hydrated CuH-clinoptilolite (CuH-Clino) and in CuLi-Clino,
but only two molecules of water in hydrated CuNa-Clino and CuK-Clino.
Two cupric ion sites are observed in many cases and are attributed to
sites in ten-ring and eight-ring main channels. Activation to 400
degrees C is sufficient to remove these water molecules and cause
migration of Cu2+ to an eight-ring intersecting channel. Adsorption of
polar molecules such as water, ammonia, alcohols, and acetonitrile
causes the migration of Cu2+ into the main channels to coordinate with
the adsorbates. Cu2+ forms complexes with three molecules of ethanol and
four of ammonia in CuH-Clino, but only coordinates to two molecules of
ethanol or methanol and three of ammonia in CuNa-Clino, and to one
molecule of ethanol or methanol and three of ammonia in CuK-Clino. Cu2+
coordinates four molecules of acetonitrile at the center of a main
channel in clinoptilolite, and this coordination number is unaffected by
the alkali metal cocations.
RI Zhao, Dongyuan/E-5796-2010
TC 6
ZB 0
Z8 0
ZS 0
Z9 6
SN 1089-5647
UT WOS:A1997XJ43800018
ER
PT J
AU Baranovskaya, OE
Zinenko, OG
Zhiznevskii, VM
TI Production of methyl tert-butyl ether in the presence of a natural
zeolite-clinoptilolite
SO RUSSIAN JOURNAL OF APPLIED CHEMISTRY
VL 70
IS 4
BP 661
EP 663
PD APR 1997
PY 1997
AB The possibility of using Carpathian clinoptilolite as a catalyst for
production of methyl tert-butyl ether by alkylation of methanol with
isobutylene in the gas phase was examined.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1070-4272
UT WOS:000071093700034
ER
PT J
AU Arcoya, A
Seoane, XL
Soria, J
TI Effect of iron on the deactivation of Ni/clinoptilolite catalysts by
thiophene poisoning
SO JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
VL 68
IS 2
BP 171
EP 176
DI 10.1002/(SICI)1097-4660(199702)68:2<171::aid-jctb621>3.0.CO;2-D
PD FEB 1997
PY 1997
AB Deactivation of several Ni catalysts supported on a K-clinoptilolite
containing iron species was analyzed in the hydrogenation of
ethylbenzene in the presence of thiophene. The location and coordination
of iron in the zeolite was modified by different thermal treatments
given to the catalysts. Studies by ESR showed that the state of iron
affects the nature and strength of the iron-nickel interaction.
Experimental results indicated the existence of a correlation between
that interaction and the resistance of the catalysts to thiophene
poisoning, in such a way that the stronger the iron-nickel interaction
the higher the sulfur resistance. An interpretation of the differences
in sulfur resistance of the catalysts based on the formation of surface
electron-deficient Ni species by interaction of Ni particles with Fe3+
of the zeolite is discussed.
TC 10
ZB 0
Z8 0
ZS 0
Z9 10
SN 0268-2575
UT WOS:A1997WH71700007
ER
PT J
AU Li, WY
Feng, J
Xie, KC
Guo, SC
TI Effects of supports on the activity of nickel catalyst for CH4 reforming
with CO2
SO PETROLEUM SCIENCE AND TECHNOLOGY
VL 15
IS 3-4
BP 297
EP 306
DI 10.1080/10916469708949658
PD 1997
PY 1997
AB Nickel catalyst is an effective catalyst for reforming CH4 with CO2. The
reaction between CO2 and CH4 at 1073K in the pressure of 0.1MPa has been
studied over different materials supported nickel metal in a fixed-bed
reactor. Different catalysts before and after reaction were
characterized by SEM, XRD, XPS. Results shows that CO and H-2 are
basically produced at the same ratio. When the feed ratio CO2/CH4 is
less than 0.5, less C-2 similar to C-4 hydrocarbons are detected. When
the feed ratio CO2/CH4 is 1, Ni/alpha-Al2O3 catalyst has the highest
activity. However, when the feed ratio CO2/CH4 is greater than 1,
Ni/gamma-Al2O3, Ni/alpha-Al2O3, Ni/SiO2 and Ni/HZSM-5 had higher
activity; Ni/clinoptilolite basically no activity. Different kinds of
carbon deposit are established.
RI FENG, JIE/B-5793-2011
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 1091-6466
UT WOS:A1997WU78400006
ER
PT J
AU Borko, L
Nagy, I
Schay, Z
Guczi, L
TI Low and high activity states in the oxidation of m-xylene on pallidum
catalysts
SO APPLIED CATALYSIS A-GENERAL
VL 147
IS 1
BP 95
EP 108
DI 10.1016/S0926-860X(96)00211-6
PD NOV 19 1996
PY 1996
AB Low and high activity states in the carbon dioxide vs. inlet temperature
transient curves in the catalytic combustion of m-xylenes over
Pd2Ni50Nb48 amorphous alloy ribbons (I), Pd/stainless steel flakes (II)
and Pd/clinoptilolite (III) samples have been investigated. in addition,
in both states hysteresis, in high activity state self-sustained
oscillation in the CO2 vs. time at full conversion and damped
oscillation at low conversion were observed over samples (II) and (III).
It was established that hysteresis is a general phenomenon in both
states and is not affected by the catalyst structure, but it can be
ascribed to Pd as active component. Transition between the low and high
activity state may be due to change in the PdO structure as was
indicated by XPS studies. Oscillation is indicative of the partial
accumulation of carbonaceous deposits over the catalysts at full
conversion, while damped oscillation might be a result of the change of
local concentration due to overheating the catalyst sample during
combustion.
TC 8
ZB 2
Z8 0
ZS 0
Z9 8
SN 0926-860X
UT WOS:A1996VU70800008
ER
PT J
AU Kallo, D
Onyestyak, G
TI Adsorption of acetylene and water on zeolites resulting in hydration to
acetaldehyde
SO ZEOLITES
VL 17
IS 5-6
BP 489
EP 494
DI 10.1016/S0144-2449(96)00074-7
PD NOV-DEC 1996
PY 1996
AB Adsorption of water and acetylene on Cd forms of LTA, X-, and Y,FAU,
ERI, CHA, PHI, MOR, MFI, and clinoptilolite active in the catalytic
hydration of acetylene at 453 K and the adsorption of acetylene on
inactive H, Na, Co, and La forms of Y,FAU were studied with i.r.
spectroscopy at 298 K. Acetylene (1) adsorbs on acidic OH groups; (2) is
weakly bound to cations (nu(C=C) = 1,958 cm(-1)); (3) forms cadmium
acetylide (nu(C=C) = 1,947 cm(-1)); and (4) is linked in side-on
configuration to Cd2+ (nu(C=C) = 1,930 cm(-1)). Water dissociated
heterolytically was found to react with adsorbed acetylene. Formation of
adsorbed acetaldehyde was observed on Cd zeolite catalysts as well as on
catalytically inactive forms of faujasite but not on H-F,FAU. (C)
Elsevier Science Inc. 1996
TC 12
ZB 0
Z8 1
ZS 0
Z9 12
SN 0144-2449
UT WOS:A1996VP43300014
ER
PT J
AU Onyestyak, G
Kallo, D
TI Interactions of reactants in hydration of acetylene on Cd-zeolite
catalysts
SO JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
VL 106
IS 1-2
BP 103
EP 108
DI 10.1016/1381-1169(95)00265-0
PD MAR 23 1996
PY 1996
AB IR measurements were carried out with Cd-MFI and Cd-clinoptilolite at 25
degrees C. Samples of different water content were contacted with
acetylene at different pressures. Adsorbed acetaldehyde was formed from
acetylene and water both adsorbed on similar Cd(2+)Z(2)(-) sites. The
reaction between the two adsorbed reactants reveals the validity of
Langmuir-Hinshelwood kinetics. Decrease of water content or increase of
acetylene pressure facilitated the formation of carbonaceous deposits
especially in the case of Cd-MFI. Deposits formed from acetylene
displace adsorbed acetylene and acetaldehyde.
TC 10
ZB 0
Z8 0
ZS 0
Z9 10
SN 1381-1169
UT WOS:A1996UE00100013
ER
PT J
AU Woo, HC
Lee, KH
Lee, JS
TI Catalytic skeletal isomerization of n-butenes to isobutene over natural
clinoptilolite zeolite
SO APPLIED CATALYSIS A-GENERAL
VL 134
IS 1
BP 147
EP 158
DI 10.1016/0926-860X(95)00216-2
PD JAN 4 1996
PY 1996
AB The proton form of a natural zeolite, clinoptilolite, was found to be an
efficient catalyst for the skeletal isomerization of n-butenes to
isobutene. The acidity and characteristic pore structure of this zeolite
appeared to be responsible for the good performance. The effects of
process variables were studied. When reaction conditions were chosen
such that the dimerization reaction, the major side reaction, was
suppressed, high selectivities to isobutene were obtained.
TC 38
ZB 1
Z8 0
ZS 0
Z9 38
SN 0926-860X
UT WOS:A1996TQ31100011
ER
PT J
AU KALLO, D
MIHALYI, RM
TI MECHANISM OF 1-BUTENE HYDRATION OVER ACIDIC ZEOLITE AND ION-EXCHANGE
RESIN CATALYSTS
SO APPLIED CATALYSIS A-GENERAL
VL 121
IS 1
BP 45
EP 56
DI 10.1016/0926-860X(95)85009-0
PD JAN 5 1995
PY 1995
AB Vapour-phase hydration of 1-butene at atmospheric pressure above 373 K
shows similar features on both H-clinoptilolite and sulphonic acid
ion-exchange resin: the initial reaction rate linearly increases with
the partial pressure of 1-butene and passes through a maximum as a
function of water pressure. Kinetics was evaluated accordingly. A
decrease in the 1-butene isomerization rate indicated that under
hydration conditions more than 99.9% of the acidic sites are hydrated.
For the hydration, however, hydroxonium ions are the active centres
where an adsorbed water molecule reacts with gas-phase 1-butene in the
rate determining step. The equilibrated desorption of secondary butanol
ends the reaction. The kinetic inhibition by butanol can be suppressed
with water. Above ca. 0.2 bar water pressure inactive polydrated
hydroxonium ions are formed.
TC 13
ZB 0
Z8 2
ZS 0
Z9 13
SN 0926-860X
UT WOS:A1995QC45000006
ER
PT J
AU Alimardanov, KM
Abdullayev, AF
TI Dehydroisomerization and oxidative dehydrogenation of 4-vinylcyclohexene
on oxide and zeolite catalysts
SO PETROLEUM CHEMISTRY
VL 35
IS 6
BP 508
EP 520
PD 1995
PY 1995
AB An investigation has been made of the dehydroisomerization and oxidative
dehydrogenation of 4-vinylcyclohexene in the presence of a
copper-magnesium oxide system, and also modified forms of H-mordenite
and H-clinoptilolite. The highest selectivity of the reaction and the
highest overall yields of ethylbenzene and styrene were obtained on
zeolite catalysts in the presence of air oxygen. At a temperature of
400-470 degrees C and with a hydrocarbon/O-2/N-2 molar ratio of 1:0 3:4,
the overall yield of ethylbenzene and styrene on Fe-Gd-K-O/H-mordenite
and Fe-Tb-K-O/H-clinoptilolite amounts to 44.7-77.6%.
The introduction of carbon dioxide into the reaction mixture promotes a
reduction in the rate of degradative oxidation of 4-vinylcyclohexene and
an increase in the selectivity of the process with respect to
ethylbenzene and styrene. On the basis of experimental data, possible
mechanisms of the reaction are proposed.
TC 1
ZB 0
Z8 0
ZS 0
Z9 1
SN 0965-5441
UT WOS:A1995UH07500007
ER
PT B
AU BERTEA, LE
KOUWENHOVEN, HW
PRINS, R
BE Weitkamp, J
Karge, HG
Pfeifer, H
Holderich, W
TI VAPOR-PHASE NITRATION OF BENZENE OVER ZEOLITIC CATALYSTS
SO ZEOLITES AND RELATED MICROPOROUS MATERIALS: STATE OF THE ART 1994
SE STUDIES IN SURFACE SCIENCE AND CATALYSIS
VL 84
BP 1973
EP 1980
PN A-C
PD 1994
PY 1994
AB Catalysts based on zeolite Y, mordenite, ZSM-5 and clinoptitolite were
applied in the gas phase nitration of benzene with nitric acid. Catalyst
performance depended on crystal structure, crystallinity, lattice
composition, external surface area and mesoporosity. Non framework
aluminium acted as a catalyst poison. Best results were obtained with a
clinoptilolite based catalyst.
CT 10th International Zeolite Conference
CY JUL 17-22, 1994
CL GARMISCH PARTENKIR, GERMANY
TC 16
ZB 0
Z8 0
ZS 0
Z9 16
BN 0-444-81847-2
UT WOS:A1994BD02E00244
ER
PT J
AU IACOMI, F
TRIF, E
POPOVICI, E
TI A STUDY OF THE CATION ZEOLITIC SURFACE INTERACTION BY ESR SPECTROSCOPY
SO APPLIED SURFACE SCIENCE
VL 65-6
BP 298
EP 301
DI 10.1016/0169-4332(93)90675-2
PD MAR 1993
PY 1993
AB The present work uses ESR spectroscopy to locate and characterize the
cation-zeolitic surface interaction of molybdenum ions incorporated in
H-clinoptilolite by liquid-phase ion exchange and by a solid-state
reaction. Both studied cases show that ion location and interaction with
the cation-zeolitic surface are almost the same and the ions migrate
between sites upon dehydration and adsorption, forming dimer species.
Models are given about the distribution and environments of molybdenum
ions in zeolite.
CT 6TH INTERNATIONAL CONF ON SOLID FILMS AND SURFACES
CY JUN 29-JUL 03, 1992
CL PARIS, FRANCE
SP FRENCH MINIST RES & SPACE; CHAMBRE COMMERCE & IND PARIS; UNIV PIERRE &
MARIE CURIE; CEA; CNRS; CTR NATL ETUDES TELECOMMUN; MARNE VALLEE VILLE
NOUVELLE; THOMSON CSF; ST GOBAIN; APPLE
RI Cuza, UAIC/D-2604-2009; Iacomi, Felicia/C-5755-2012
OI Iacomi, Felicia/0000-0001-7952-3741
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0169-4332
UT WOS:A1993KW45800051
ER
PT J
AU ARCOYA, A
SEOANE, XL
SORIA, J
TI SULFUR RESISTANCE OF NICKEL-CATALYSTS SUPPORTED ON K-CLINOPTILOLITE
CONTAINING IRON IN ETHYLBENZENE HYDROGENATION
SO STUDIES IN SURFACE SCIENCE AND CATALYSIS
VL 75
BP 2341
EP 2344
PN C
PD 1993
PY 1993
AB The deactivation of Ni catalysts supported on a K-Clinoptilolite
containing iron species was studied in the hydrogenation of ethylbencene
in presence of thiophene. The coordination and location of the Fe3+
species was modified by thermal treatments. A correlation between the
nickel-iron interaction, evidenced by ESR, and the sulfur-resistance was
found. So, the sample calcined before the Ni impregnation has shown a
stronger interaction and higher sulfur-resistance. The contrary was
observed for a sample from which iron had been previously extracted. An
interpretation of the catalyst resistance towards thiophene poisoning
based on either the formation of surface electron-deficient Ni species
or the decoration of Ni particles by Fe3+ segregated by calcination is
discussed.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0167-2991
UT WOS:A1993MK93400111
ER
PT J
AU GONZALES, JA
TRAVIESO, N
RKOYA, A
SEOANE, JL
TI CATALYTIC PROPERTIES OF MODIFIED NATURAL CLINOPTILOLITE
SO KINETICS AND CATALYSIS
VL 32
IS 4
BP 817
EP 821
PN 2
PD JUL-AUG 1991
PY 1991
AB Natural clinoptilolite with a high concentration of calcium and
magnesium was investigated. Exchange with ammonium ions is effective for
total decationization of the zeolite and preparation of a catalyst with
a high acidity, but with organic access to o-xylene molecules. Zeolites
dealuminated with HCl can conduct the reaction with the participation of
bimolecular complexes in conversion of ethanol and o-xylene.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0023-1584
UT WOS:A1991HK99000001
ER
PT J
AU KALLO, D
ONYESTYAK, G
TI CATALYTICALLY ACTIVE TRANSITION-METAL IONS IN ZEOLITES
SO MAGYAR KEMIAI FOLYOIRAT
VL 96
IS 9-10
BP 436
EP 444
PD SEP-OCT 1990
PY 1990
AB Both the interconversion of n-butenes and the oligomerization of
iso-butene proceed on acid sites as well as on transition metal ions in
cationic positions of zeolites. The reaction mechanisms are different
on these two types of zeolite catalysts. The addition of hydrogen
sulphide to olefins resulting exclusively in the formation of thiols and
thioethers are catalysed by transition metal ions introduced into
zeolites. On the same catalyst the two products can be converted into
each other. Acetylene can be hydrated to acetaldehyde with high
selectivity on late transition metal-forms of zeolites, when acid sites
are not generated and metal ions are not reduced. Cd-clinoptilolite
proved to be the most suitable catalyst.
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0025-0155
UT WOS:A1990EV38400009
ER
PT J
AU HUTCHINGS, GJ
THEMISTOCLEOUS, T
COPPERTHWAITE, RG
TI METHANOL CONVERSION TO HYDROCARBONS USING A MODIFIED SOUTH-AFRICAN
CLINOPTILOLITE CATALYST - INVESTIGATION OF CATALYST LIFETIME
SO SOUTH AFRICAN JOURNAL OF CHEMISTRY
VL 41
IS 4
BP 157
EP 160
PD DEC 1988
PY 1988
TC 0
ZB 0
Z8 0
ZS 0
Z9 0
SN 0379-4350
UT WOS:A1988U150100007
ER
PT J
AU HUTCHINGS, GJ
THEMISTOCLEOUS, T
COPPERTHWAITE, RG
TI METHANOL CONVERSION TO HYDROCARBONS USING MODIFIED CLINOPTILOLITE
CATALYSTS - INVESTIGATION OF CATALYST LIFETIME AND REACTIVATION
SO APPLIED CATALYSIS
VL 43
IS 1
BP 133
EP 140
DI 10.1016/S0166-9834(00)80906-9
PD OCT 17 1988
PY 1988
TC 7
ZB 0
Z8 0
ZS 0
Z9 7
SN 0166-9834
UT WOS:A1988Q466600013
ER
PT J
AU PAPP, J
MIKLOSY, E
TI ISOMERIZATION OF M-XYLENE ON H-MORDENITE AND H-CLINOPTILOLITE CATALYSTS
SO REACTION KINETICS AND CATALYSIS LETTERS
VL 8
IS 1
BP 87
EP 92
DI 10.1007/BF02070353
PD 1978
PY 1978
TC 3
ZB 0
Z8 0
ZS 0
Z9 3
SN 0133-1736
UT WOS:A1978EV08100016
ER
EF
