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Title: Preparation and thermal properties of Zr-intercalated clays

Abstract

Montmorillonites intercalated by zirconium macrocations have been prepared. Diffusion of the Zr cations within the particles of clay controls the rate of ion exchange, and hence the distribution of the Zr pillars. This effect accounts for the influence of particle size on the degree of exchange, the surface area, and the thermal stability of the pillared clay. The thermal stability of the Zr clays prepared under these conditions is limited to 973 K in dry air. The changes in microporosity, evaluated from nitrogen adsorption using the equation of Dubinin, show that collapse of the structure occurs by sintering of the pillars. This sintering can be decreased by doping the pillars with rare earth cations. The resulting material then retains a surface area of 180 m{sup 2}/g after calcination at 1023 K in dry air, and is more acidic than the corresponding Zr-clay.

Authors:
; ; ;  [1];  [2]
  1. (Laboratoire de Chimie Organique Physique et Cinetique Chimique Appliquees, Montpellier (France))
  2. (Laboratoire de Chimie Physique, Montpellier (France))
Publication Date:
OSTI Identifier:
6843771
Alternate Identifier(s):
OSTI ID: 6843771
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Catalysis; (USA); Journal Volume: 119:1
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; CATALYSTS; CHEMICAL PREPARATION; MONTMORILLONITE; PHYSICAL PROPERTIES; STABILITY; ZIRCONIUM; ION EXCHANGE; ADSORPTION; CALCINATION; CATALYTIC CRACKING; DIFFUSION; DOPED MATERIALS; MICROSTRUCTURE; NITROGEN; PARTICLE SIZE; PETROLEUM FRACTIONS; PH VALUE; POROSITY; RARE EARTHS; SINTERING; SURFACE AREA; VISCOSITY; CHEMICAL REACTIONS; CLAYS; CRACKING; CRYSTAL STRUCTURE; DECOMPOSITION; ELEMENTS; ENERGY SOURCES; FABRICATION; FOSSIL FUELS; FUELS; INORGANIC ION EXCHANGERS; ION EXCHANGE MATERIALS; MATERIALS; METALS; NONMETALS; PETROLEUM; PYROLYSIS; SIZE; SORPTION; SURFACE PROPERTIES; SYNTHESIS; THERMOCHEMICAL PROCESSES; TRANSITION ELEMENTS 020400* -- Petroleum-- Processing

Citation Formats

Figueras, F., Mattrod-Bashi, A., Fetter, G., Thrierr, A., and Zanchetta, J.V. Preparation and thermal properties of Zr-intercalated clays. United States: N. p., 1989. Web. doi:10.1016/0021-9517(89)90137-1.
Figueras, F., Mattrod-Bashi, A., Fetter, G., Thrierr, A., & Zanchetta, J.V. Preparation and thermal properties of Zr-intercalated clays. United States. doi:10.1016/0021-9517(89)90137-1.
Figueras, F., Mattrod-Bashi, A., Fetter, G., Thrierr, A., and Zanchetta, J.V. Fri . "Preparation and thermal properties of Zr-intercalated clays". United States. doi:10.1016/0021-9517(89)90137-1.
@article{osti_6843771,
title = {Preparation and thermal properties of Zr-intercalated clays},
author = {Figueras, F. and Mattrod-Bashi, A. and Fetter, G. and Thrierr, A. and Zanchetta, J.V.},
abstractNote = {Montmorillonites intercalated by zirconium macrocations have been prepared. Diffusion of the Zr cations within the particles of clay controls the rate of ion exchange, and hence the distribution of the Zr pillars. This effect accounts for the influence of particle size on the degree of exchange, the surface area, and the thermal stability of the pillared clay. The thermal stability of the Zr clays prepared under these conditions is limited to 973 K in dry air. The changes in microporosity, evaluated from nitrogen adsorption using the equation of Dubinin, show that collapse of the structure occurs by sintering of the pillars. This sintering can be decreased by doping the pillars with rare earth cations. The resulting material then retains a surface area of 180 m{sup 2}/g after calcination at 1023 K in dry air, and is more acidic than the corresponding Zr-clay.},
doi = {10.1016/0021-9517(89)90137-1},
journal = {Journal of Catalysis; (USA)},
number = ,
volume = 119:1,
place = {United States},
year = {Fri Sep 01 00:00:00 EDT 1989},
month = {Fri Sep 01 00:00:00 EDT 1989}
}
  • The exchange of Cd{sup 2+} ions, obtained by several methods, in crystalline {gamma}-zirconium hydrogen phosphate was investigated. The thermal behavior was studied and structural characterization of converted phases was performed. It was found that, after being heated at 320 C, when layered structure is still present, the fully exchanged cadmium material rehydrates in air and returns to the initial phase obtained at room temperature. The molecular intercalate with CdS was also prepared and characterized. Its layered structure and X-ray diffractograms matched those of the starting precursor {gamma}-zirconium phosphate.
  • Indium and gallium monoselenides can be intercalated by hydrogen ions. Thermodynamic parameters have been calculated for the intercalation and the proton diffusion coefficient in the van der Waals' spaces has been determined. The effects of hydrogen intercalation on the resistance perpendicular to the layers in InSe and GaSe have been determined.
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  • Methods for intercalating thermally stable, polynuclear hydroxy metal cations and/or metal cluster cations in smectite clays have been developed in recent years as a means of keeping separate the silicate layers in the absence of a swelling solvent. Since the pillaring cations are space filling, the interlamellar reaction space will be broken up into an interconnected set of channels through which a diffusing species can migrate. In this paper, a lattice model is designed to determine how different spatial distributions of pillaring agents and different interlamellar spacings can influence the efficiency of reaction between a fixed target molecule and amore » diffusing coreactant. The authors study two regular distributions of pillaring cations and calculate the mean reaction time (as calibrated by the mean walklength ) of the diffusing coreactant as a function of the separation between silicate layers. All other factors being held constant, they find a significant increase in the reaction efficiency with increase in the number of channels available to the coreactant. They also find that for each distribution there is a decrease in reaction efficiency as one increases the interlayer spacing, with the surprising result that for large arrays the addition of one or two layers above the basal plane (where the target molecule is anchored at the centrosymmetric site) leads to essentially the same relative changes in the reaction efficiency regardless of the spatial distribution considered.« less
  • Graphical abstract: - Highlights: • Ca–Zr substituted Bi-YIG has been prepared via mechanochemical processing and heat treatment. • Structural and magnetic properties were investigated. • Magnetic measurements showed the Ferrimagnetic behavior for pure garnet structure samples. • The spherical morphology of the nanoparticles was found from the SEM micrograph. - Abstract: Ca–Zr substituted (Bi-YIG) nanopowders with a nominal composition of BiY{sub 2−x}Ca{sub x}Zr{sub y}Fe{sub 5−y}O{sub 12} (x = y and x varied from 0.00 to 1.25 by the step of 0.25) were prepared by mechanochemical processing (MCP) and subsequent heat treatments. The effect of dopant mol ratios, on garnet phasemore » formation were investigated by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. The lattice constant of the samples increased by increasing Zr{sup 4+} content (for x ≤ 1). Mean crystallite size of the single-phase powders, which was evaluated by Scherrer's formula, was about 35 nm. The experimental results show that the Ca–Zr substitution Bi-YIG lowers the calcining and sintering temperatures for x < 1. The results show that the single-phase nanopowders can be obtained at temperatures below 850 °C. The measurements of vibrating sample magnetometer (VSM) show that the saturation magnetization of the samples increases as x increase from 0.00 to 0.25 and then decreases by increasing x to the values greater than 0.25.« less