New Theoretical Expressions for the Five Adsorption Type Isotherms Classified by Bet Basing on Statistical Physics Treatment

Abstract

New theoretical expressions to model the five adsorption Type isotherms have been established. Using the grand canonical ensemble in statistical physics, we could give an analytical expression to each five physical adsorption Type isotherms classified by Brunauer-Emetter-Teller, called often BET isotherms [1]. The establishment of these expressions is based on statistical physics treatment and theoretical considerations. This method allowed an estimation of all the mathematical parameters in the models. The physico-chemical parameters intervening in the adsorption process that present the models could deduced directly from the adsorption isotherms with numerical simulation. We determine the adequate model for each Type isotherm, which fixes with direct numerical simulation the monlayer, multilayer or condensation character. The new theoretical expressions that we have proposed, basing on statistical physics treatment, are rather powerful to better understand and interpret the various five physical adsorption Type isotherms at a microscopic level.


(Af. J. of Science and Technology: 2002 3(2): 67-75)