Review article

Enthalpy of Interfacial Charging of Metal Oxide / Water Systems

Nikola Kallay ; Laboratory of Physical Chemistry, Faculty of Science, University of Zagreb, P. O. Box 163, 41001 Zagreb, Croatia
Suzana Žalac ; Laboratory of Physical Chemistry, Faculty of Science, University of Zagreb, P. O. Box 163, 41001 Zagreb, Croatia

Abstract

The relationships between different assumed stoichiometries of charging the metal oxide/aqueous solution interface are discussed. The problem of evaluating the enthalpies of protonation, A H° and deprotonation, Adfl“ of surface amphotheric groups was analyzed. In order to obtain the standard values of reaction enthalpies, one needs to add the base (or acid) to the acidic (or basic) suspension in calorimeter in such a manner that the point of zero charge (p.z.c.) lies precisely in the middle between the initial and the final pH. The value of AAH° - A H° evaluated by this procedure corresponds to the enthalpy difference obtained from the p.z.c. dependence on temperature. The results with silica suspension were demonstrated. The value obtained by calorimetry, AdH° - ApH° = 34.4 kJ mol-1, agrees with the result of the pHpzc(T) measurements (32.5 kJ mol-1).

Keywords

Hrčak ID:

136769

URI

https://hrcak.srce.hr/136769

Publication date:

1.12.1994.

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