Transformations of gamma-alumina in aqueous ...
Document type :
Article dans une revue scientifique: Article original
PMID :
Permalink :
Title :
Transformations of gamma-alumina in aqueous suspensions 1. Alumina chemical weathering studied as a function of pH
Author(s) :
Carrier, X. [Auteur]
Marceau, Eric [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Lambert, J. F. [Auteur]
Che, M. [Auteur]
Marceau, Eric [Auteur]

Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Lambert, J. F. [Auteur]
Che, M. [Auteur]
Journal title :
J. Colloid Interface Sci.
Abbreviated title :
J. Colloid Interface Sci.
Pages :
429-437
Publication date :
2007-04-15
ISSN :
0021-9797
English keyword(s) :
oxide support
chemical weathering
hydration
dissolution
aluminum hydroxide
alumina
chemical weathering
hydration
dissolution
aluminum hydroxide
alumina
HAL domain(s) :
Chimie
English abstract : [en]
Hydration of γ-Al2O3 is often reported to occur via the superficial transformation of the alumina surface into aluminum hydroxide-like layers. However, very little evidence has been given so far to support this hypothesis. ...
Show more >Hydration of γ-Al2O3 is often reported to occur via the superficial transformation of the alumina surface into aluminum hydroxide-like layers. However, very little evidence has been given so far to support this hypothesis. It is demonstrated here by X-ray diffraction, TEM, electron diffraction, and solubility studies that a second process of hydration takes place that involves the dissolution of alumina and subsequent precipitation of well-shaped Al(OH)3 particles from supersaturated alumina aqueous solution. This process can be observed on a macroscopic scale (XRD, TEM) for any , provided that the contact time between alumina and water exceeds 10 h. The least thermodynamically stable phase of aluminum hydroxide, bayerite, becomes favored compared with gibbsite when the pH of the solution is increased. It is assumed that the rate of formation of bayerite germs is greater than that of gibbsite due to variations in aluminum speciation in solution as a function of pH.Show less >
Show more >Hydration of γ-Al2O3 is often reported to occur via the superficial transformation of the alumina surface into aluminum hydroxide-like layers. However, very little evidence has been given so far to support this hypothesis. It is demonstrated here by X-ray diffraction, TEM, electron diffraction, and solubility studies that a second process of hydration takes place that involves the dissolution of alumina and subsequent precipitation of well-shaped Al(OH)3 particles from supersaturated alumina aqueous solution. This process can be observed on a macroscopic scale (XRD, TEM) for any , provided that the contact time between alumina and water exceeds 10 h. The least thermodynamically stable phase of aluminum hydroxide, bayerite, becomes favored compared with gibbsite when the pH of the solution is increased. It is assumed that the rate of formation of bayerite germs is greater than that of gibbsite due to variations in aluminum speciation in solution as a function of pH.Show less >
Language :
Anglais
Administrative institution(s) :
Université de Lille
CNRS
Centrale Lille
ENSCL
Univ. Artois
CNRS
Centrale Lille
ENSCL
Univ. Artois
Collections :
Research team(s) :
Matériaux pour la catalyse (MATCAT)
Submission date :
2023-05-30T18:22:23Z