A New Approach for Modelling Heterogeneous Surfaces

Abstract

In present work, the scope of a new approach for modelling heterogeneous surface isotherms and differential adsorption heats for a discrete heterogeneous surface with three kinds of sites has been examined. All the various kinds of experimentally observed dependencies of the differential adsorption heats on the surface coverage described in the literature have been reproduced. The increase in differential adsorption heat with surface coverage of a heterogeneous surface has been shown to be possible when the pre-exponential factor changes in moving from one kind of site to another. In this connection, it has been proposed that the heterogeneous surface should be characterized not only by the dependence of the adsorption heats on the distribution of active sites but also by the adsorption coefficient. The parameters for the adsorption of propan-2-ol on γ-aluminium oxide have been calculated from adsorption/calorimetric data.

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