Non-Dissociative Gas Adsorption with Different Chemisorption Geometries on Nanoporous Surfaces

Isotherm equation is one of the important scientific bases for adsorbent selection. There are different isotherms that do not account for an adsorbate, different chemisorption geometries on the nanoporous surface. It is interesting to introduce a general isotherm, which considers different chemisorption geometries of an adsorbate on nanoporous surfaces. In this study, an isotherm for non-dissociative gas adsorption on nanoporous surface was derived by classical thermodynamics. Theoretical study of thermodynamics of adsorption leads to the concept of a constant parameter a which shows the ratio of the number of occupied sites to the number of adsorbed molecules. The derived isotherm was analyzed by several experimental systems of non-dissociative gas adsorption on nanoporous surfaces. By using experimental data, a comparison between the derived isotherm with some famous isotherms like Langmuir, Sips, Toth and Frumkin was provided.