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Kinetic Size Effect During Dissolution of a Synthetic gamma-Alumina

Roelofs, F. and Vogelsberger, W. and Buntkowsky, G. (2008):
Kinetic Size Effect During Dissolution of a Synthetic gamma-Alumina.
In: Zeitschrift Fur Physikalische Chemie-International Journal of Research in Physical Chemistry & Chemical Physics, 222 (8-9), pp. 1131-1153, [Online-Edition: http://apps.webofknowledge.com/full_record.do?product=WOS&se...],
[Article]

Abstract

The dissolution process of a technical, nanodispersed gamma-alumina in water was Studied at 25 degrees C in the pH range 3.0 <= pH <= 11.5. Thereby, especial attention was paid to the influeuce of supersaturation on the dissolution behaviour observed. In conclusion, we were able to verify a size effect during the dissolution process. in the whole pH range investigated. In addition. we observed that changing supersaturation under identical conditions. leads to a shift of the maximum in the concentration profiles both, in absolute value and in time, when the maximum Occurs. X-ray powder diffraction analysis and nitrogen adsorption measurements Were used to identify the solid material collected during,,elected dissolution experiments. As a result, the formation Of the aluminium phase -bayerite/gibbsite- could be excluded as a possible reason for the observed dissolution behaviour. The rate constants of the dissolution process were evaluated using the model of Gibbs free energy Of Cluster formation, which considers size effect among other factor. As it result, we were able to prove that the observed maxima in the concentration profiles were due to a kinetic size effect, Caused by the size of the primary particles of the starting material. Surface tension, and supersaturation in the system.

Item Type: Article
Erschienen: 2008
Creators: Roelofs, F. and Vogelsberger, W. and Buntkowsky, G.
Title: Kinetic Size Effect During Dissolution of a Synthetic gamma-Alumina
Language: English
Abstract:

The dissolution process of a technical, nanodispersed gamma-alumina in water was Studied at 25 degrees C in the pH range 3.0 <= pH <= 11.5. Thereby, especial attention was paid to the influeuce of supersaturation on the dissolution behaviour observed. In conclusion, we were able to verify a size effect during the dissolution process. in the whole pH range investigated. In addition. we observed that changing supersaturation under identical conditions. leads to a shift of the maximum in the concentration profiles both, in absolute value and in time, when the maximum Occurs. X-ray powder diffraction analysis and nitrogen adsorption measurements Were used to identify the solid material collected during,,elected dissolution experiments. As a result, the formation Of the aluminium phase -bayerite/gibbsite- could be excluded as a possible reason for the observed dissolution behaviour. The rate constants of the dissolution process were evaluated using the model of Gibbs free energy Of Cluster formation, which considers size effect among other factor. As it result, we were able to prove that the observed maxima in the concentration profiles were due to a kinetic size effect, Caused by the size of the primary particles of the starting material. Surface tension, and supersaturation in the system.

Journal or Publication Title: Zeitschrift Fur Physikalische Chemie-International Journal of Research in Physical Chemistry & Chemical Physics
Volume: 222
Number: 8-9
Uncontrolled Keywords: dissolution alumina kinetic size effect entstehenden kristallinen formen aqueous-electrolyte solutions acid-base reactions oxygen-exchange solubility oxide adsorption speciation chemistry gibbsite
Divisions: 07 Department of Chemistry
07 Department of Chemistry > Physical Chemistry
Date Deposited: 27 Oct 2014 20:48
Official URL: http://apps.webofknowledge.com/full_record.do?product=WOS&se...
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376CU Times Cited:0 Cited References Count:53

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