Abstract: In this paper, the adsorption is studied in the light of statistical mechanics, with the result that a universal isotherm equation of the adsorption has been found, and the practical isotherm equation for real gases is given when the interaction between gas molecules is depicted in terms of Keesom and the Lennard-Jones potential. The experimental isotherms of the adsorption of medium and micro aperture charcoal are measured. It is seen that the agreement between theoretical and experimental isotherms of micro aperture charcoal is satisfred.

Key words: multimolecular adsorption, statistical mechanics, real gas, isotherm equation