On the enthalpic effects accompanying the mixed-gas adsorption on heterogeneous solid surfaces: a theoretical description based on the integral equation approach

Theoretical description of mixed-gas adsorption equilibria can be made in many ways depending on various physical assumptions and approaches used. In this paper the possibilities of the IE (integral equation) approach to solve that important theoretical problem are examined. The extension of the Langmuir–Freundlich equation for the case of mixed-gas adsorption and corresponding expressions for isosteric heats of adsorption are presented. To predict isosteric heats of gas mixture components, the knowledge of only single-gas adsorption and calorimetric data are required. A special attention is given to possibilities of arriving at relatively simple analytical or combined analytical/numerical solutions.