Abstract
Adsorption isotherms have important practical applications, including in interface chemistry where they have been used to model adsorbate/adsorbent interactions. Basing on the grand canonical formalism in statistical physics, a finite multilayer model with multisite occupancy was established. The main purpose of that work was to predict some adsorption thermodynamic parameters. Here, the model is developed further to obtain expressions for the configurational entropy, S, the Gibbs free enthalpy, G and the Helmholtz free energy, F. These calculated thermodynamic parameters are used to interpret the adsorption process and the interactions of adsorbate with each other, as well as, with the adsorbent surface. In this paper, we show how the grand canonical formalism will be emphasized for treating more advanced adsorption model with thermodynamic study.