Microporous and Mesoporous Materials

article

Editorial

Jens Weitkamp, Michael Stöcker, Steven L. Suib, Robert W. Thompson, more

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 1-2

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A functionalized porous clay heterostructure for heavy metal ion (Hg2+) trapping

Louis Mercier, Thomas J. Pinnavaia

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 101-106

A heavy metal ion adsorbent that binds Hg ²⁺ ions from solution to a capacity of 0.74 mmol/g has been prepared by grafting 3-mercaptopropyltrimethoxysilane to the intragallery framework walls of a porous fluorohectorite clay heterostructure (PCH). Up to 67% of the immobilized thiol groups are accessible for Hg ²⁺ trapping. This represents a significant improvement over previously reported...

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Crystal growth of zincophosphates from conventional media and reverse micelles: mechanistic implications

Mario J. Castagnola, Prabir K. Dutta

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 149-159

Zincophosphates can be synthesized with frameworks analogous to aluminosilicate zeolites. Previous studies have shown that reverse micelles, which are microdroplets of water dispersed in an oil-like medium, can serve as nucleation and growth centers for microporous materials. Zincophosphates with the sodalite framework can be readily made from reverse micelles, whereas the more open structure resembling...

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Sorption of water in aluminophosphate molecular sieve AlPO4-5

B.L. Newalkar, R.V. Jasra, V. Kamath, S.G.T. Bhat

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 129-137

The water sorption isotherm over AlPO ₄ -5, in which a low sorption capacity in the initial region followed by a steep rise in sorption is observed, is different from those obtained for polar molecules, namely acetonitrile, ammonia and methanol. An attempt has been made to explain the water sorption behaviour on the basis of a condensation phenomenon using the structural characteristics of...

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The incorporation of iron ions in AlPO4-5 molecular sieves after microwave synthesis studied by EPR and Mössbauer spectroscopy

A. Bruckner, U. Lohse, H. Mehner

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 207-215

FeAPO-5 samples with up to 3 mol% Fe were synthesized by microwave crystallization from Fe(II)- and Fe(III)-containing gels. The samples were studied as-synthesized and during thermal treatment in air, N ₂ and NH ₃ using in situ EPR and Mössbauer spectroscopy. The iron ions are mainly incorporated in lattice positions substituting for aluminium. During calcination, Fe(II) is easily...

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Hydrothermal synthesis and characterization of indium containing beta zeolite

M. Chatterjee, D. Bhattcharya, H. Hayashi, T. Ebina, more

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 87-91

The hydrothermal synthesis of indium containing beta zeolite has been reported. The efficiency of the synthesis depends mainly on the concentration of indium, synthesis temperature, and pH of the gel. Beta indium has been synthesized in a range of different SiO ₂ /In ₂ O ₃ ratios using tetraethylammonium ion as a template. For SiO ₂ /In ₂ O ₃ ratio around...

article

Photoluminescent properties of MCM-41 molecular sieves

Mary E. Gimon-Kinsel, Kathy Groothuis, Kenneth J. Balkus

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 67-76

The photoluminescence of as-synthesized and calcined siliceous as well as aluminosilicate MCM-41 molecular sieves was examined at 350, 300, 250 and 200 nm. The observation of high energy emission bands (hv > 2.5 eV) from the as-synthesized siliceous MCM-41 suggests the presence of oxygen related defect sites similar to those found in amorphous silica. Examination of corresponding excitation spectra...

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Structural investigation of zinc oxide clustering in zeolite A and sodalite

L. Khouchaf, M.-H. Tuilier, M. Wark, M. Soulard, more

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 27-37

The formation of small zinc oxide clusters in fully Zn-exchanged LTA zeolite and partially Zn-exchanged sodalite submitted to appropriate thermal treatments was investigated by X-ray absorption spectroscopy at the Zn K-edge. The absence of extraneous ZnO or ZnAl ₂ O ₄ particles as well as the changes in the zeolite framework produced by thermal treatments was checked by X-ray diffraction...

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Rapid synthesis of AlPO4-11 and cloverite by microwavehydrothermal processing

Man Park, Sridhar Komarneni

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 39-44

This study focuses on the rapid preparation of AlPO ₄ -11 and cloverite by microwave-hydrothermal (M-H) heating and the comparison of this heating technique with the conventional-hydrothermal (C-H) heating technique in the synthesis of these phases. By M-H heating, pure AlPO ₄ -11 phase was synthesized from boehmite at 70 psi (~150 C) within 2.5 h without pretreatment of the hydrogels...

article

Materials derived from synthetic organo-clay complexes as novel hydrodesulfurization catalyst supports

Kathleen A. Carrado, Christopher L. Marshall, James R. Brenner, Kang Song

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 17-26

A series of mesoporous synthetic organo-clay complexes has been prepared by hydrothermal crystallization of gels containing silica, magnesium hydroxide, lithium fluoride, and an organic of choice, followed by calcination to remove the organics. The organic serves to impart structural order to the inorganic network that does not disappear upon its removal. The choice of organic modifier can be used...

article

Effect of Si to Al substitution at next-nearest-neighbor sites on the acid strength 2. Low Si/Al ratio or high ammonia loading

Kazuo Teraishi

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 177-185

The acidity variations upon Si/Al substitution at next-nearest-neighbor (NNN) sites were studied by ab initio molecular orbital calculations. Our previous study on the Si/Al substitution occurring at only one NNN site (1NNN models) revealed that the effect of the substitution on the acid strength is not unique but is site-dependent [Microporous Mater. 5 (1995) 233]. In the present report, a lower...

article

Patents report

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 223,225-233

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Physical chemistry of aluminosilicate gels. Part 2 Influence of the batch molar ratio SiO2/Al2O3 on chemical composition of the gels

I. Krznarić, T. Antonić, B. Subotić

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 161-175

The influence of the batch (bN: N = I, II) molar ratio. Y=[SiO ₂ ] _bN /[Al ₂ O ₃ ] _bN , and order of mixing of aluminate and silicate solutions (A: sodium silicate to sodium aluminate solution; B: sodium aluminate to sodium silicate solution) on the distributions of Na, Al and Si between the solid (S) and the liquid (L) phase of the sodium aluminosilicate hydrogels...

article

Oxyfluorinated open framework compounds. XVIII Dehydration of single crystals of the iron phosphate ULM-12 or [Fe4(PO4)4F3(H2O)3,N2C6H14] with an open structure, structural determination and magnetic study of the dehydrated phase(ULM-19)

M. Cavellec, J.M. Grenèche, G. Férey

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 45-52

[Fe ₄ (PO ₄ ) ₄ F ₃ (H ₂ O) ₃ ,N ₂ C ₆ H ₁₄ ] or ULM-12 was the first magnetic iron phosphate with an open framework. The dehydration of single crystals of ULM-12 led to a new compound, [Fe ₄ (PO ₄ ) ₄ F ₃ ,N ₂ C ₆ H ₁₄ ] named ULM-19. Its structure was determined by single-crystal...

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Influence of high-energy ball milling on the physico-chemical and catalytic properties of titanium silicalite TS-1

D. Trong On, M.P. Kapoor, E. Thibault, J.E. Gallot, more

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 107-118

The present work aims at examining the structural stability as well as the changes in the state of titanium silicalite upon high-energy ball milling. Various techniques including XRD, BET, UV -visible, FTIR and XPS were used to monitor the physico-chemical properties of TS-1 as a function of milling time. The changes in catalytic activity of TS-1 in n-hexane oxyfunctionalization and 1-hexene epoxidation...

article

Surfactant-templated silica aerogels

Mark T. Anderson, Patricia S. Sawyer, Thomas Rieker

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 53-65

By combining the molecular silica precursor tetramethoxysilane (TMOS) with an alkaline, micellar, water: methanol solution, we form surfactant-templated silica gel (STSG) monoliths. The wet monoliths can be exchanged with ethanol and then supercritically extracted with carbon dioxide to produce surfactant-templated silica aerogels (STSAs). STSAs represent a new class of aerogels that are composed...

article

Electron spin resonance and optical spectroscopy of tubular aluminophosphate materials containing framework vanadium

Zhaohua Luan, Dongyuan Zhao, Larry Kevan

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 93-99

A series of aluminophosphate materials without (UHM-1) and with variable amounts of vanadium (VUHM-1) have been synthesized in the presence of a cationic surfactant cetyltrimethylammonium chloride and an organic base tetramethylammonium hydroxide. Powder X-ray diffraction and electron probe microanalysis show that both UHM-1 and VUHM-1 with V/Al ratios up to 0.05 possess disordered arrays of tubular...

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The effect of hydrogen on the modification of catalytic sites in CoAPO-5 and CoAPSO-5 molecular sieves

T. Tsoncheva, R. Dimitrova, Ya. Neinska

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 217-222

The effect of hydrogen during the pre-treatment stage of CoAPO-5 and CoAPSO-5 molecular sieves on the status of cobalt ions has been studied. Cobalt migration from framework to extra framework positions and formation of metal cobalt is observed. The conversion of methanol is used as a model reaction for characterization the changes in the CoAPO-5 and CoAPSO-5 molecular sieves. The role of hydrogen...

article

Synthesis and characterization of a porous zirconium arsenate, [Zr3(AsO4)4(H2O)2]-2H2O

Damodara M. Poojary, Anatoly I. Bortun, Lyudmila N. Bortun, Camino Trobajo, more

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 77-85

A zirconium arsenate compound with composition [Zr ₃ (AsO ₄ ) ₄ (H ₂ O) ₂ ] · 2H ₂ O was synthesized by the reaction of zirconium tetrapropoxide and arsenic acid under mild hydrothermal conditions and its structure was solved from the X-ray powder diffraction data. The compound crystallizes in the triclinic space group P1 with a = 8.846 (1), b = 9.393(1),...

article

Facile synthesis of synthetic todorokite (OMS-1), co-precipitation reactions in the presence of a microwave field

Elizabeth Vileno, Ying Ma, Hua Zhou, Steven L. Suib

Microporous and Mesoporous Materials > 1998 > 20 > 1-3 > 3-15

A new application of microwave heating, co-precipitation in the presence of a microwave field, has been investigated. We report herein the synthesis of the octahedral molecular sieve, OMS-1 (synthetic todorokite), a manganese oxide that also contains magnesium, sodium, and/or other cations. Microwave aging of OMS-1 has been used to produce a pure phase material with increased catalytic activity. The...

INFONA - science communication portal

Microporous and Mesoporous Materials

Editorial

A functionalized porous clay heterostructure for heavy metal ion (Hg2+) trapping

Crystal growth of zincophosphates from conventional media and reverse micelles: mechanistic implications

Sorption of water in aluminophosphate molecular sieve AlPO4-5

The incorporation of iron ions in AlPO4-5 molecular sieves after microwave synthesis studied by EPR and Mössbauer spectroscopy

Hydrothermal synthesis and characterization of indium containing beta zeolite

Photoluminescent properties of MCM-41 molecular sieves

Structural investigation of zinc oxide clustering in zeolite A and sodalite

Rapid synthesis of AlPO4-11 and cloverite by microwavehydrothermal processing

Materials derived from synthetic organo-clay complexes as novel hydrodesulfurization catalyst supports

Effect of Si to Al substitution at next-nearest-neighbor sites on the acid strength 2. Low Si/Al ratio or high ammonia loading

Patents report

Physical chemistry of aluminosilicate gels. Part 2 Influence of the batch molar ratio SiO2/Al2O3 on chemical composition of the gels

Oxyfluorinated open framework compounds. XVIII Dehydration of single crystals of the iron phosphate ULM-12 or [Fe4(PO4)4F3(H2O)3,N2C6H14] with an open structure, structural determination and magnetic study of the dehydrated phase(ULM-19)

Influence of high-energy ball milling on the physico-chemical and catalytic properties of titanium silicalite TS-1

Surfactant-templated silica aerogels

Electron spin resonance and optical spectroscopy of tubular aluminophosphate materials containing framework vanadium

The effect of hydrogen on the modification of catalytic sites in CoAPO-5 and CoAPSO-5 molecular sieves

Synthesis and characterization of a porous zirconium arsenate, [Zr3(AsO4)4(H2O)2]-2H2O

Facile synthesis of synthetic todorokite (OMS-1), co-precipitation reactions in the presence of a microwave field

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