Tungsten-oxo-species deposited on alumina. I. Investigation of the nature of the tungstates deposited on the interface of the {gamma}-alumina/electrolyte solutions at various pH`s
- Univ. of Patras and Institute of Chemical Engineering and High Temperature Chemical Processes (Greece)
The mechanism of the deposition of the W{sup vi} species from aqueous solutions on the {gamma}-alumina surface is refined in this work by investigating critical mechanistic points. A methodology recently developed to investigate the deposition of the Co{sup (II)}, Ni{sup (II)}, Cr{sup (VI)}, and Mo{sup (VI)} on {gamma}-alumina has been applied. This methodology is based on the {open_quotes}2pK/one site{close_quotes} and {open_quotes}triple-layer{close_quotes} models and involves the writing down of various deposition equilibria, and derivation of the corresponding equations, the calculation of the amount of the deposited W{sup (vi)} (through the calculated concentrations of the W{sup (vi)} species formed on {gamma}-alumina) at various values, with pH, of the {zeta}-potential and of the difference in the H{sup +} ions consumption by the support surface in the presence and absence of the W{sup (vi)} species in the impregnating solution. The comparison of the calculated values of the aforementioned parameters with the corresponding ones achieved from deposition experiments, potentiometric titrations, and microelectrophoresis allowed us to establish the mechanism of deposition of W{sup (vi)} species on {gamma}-alumina. 22 refs., 5 figs., 3 tabs.
- OSTI ID:
- 494281
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 2 Vol. 162; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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