A New Approach to Analysis of Multilayer Adsorption

Abstract

A new approach to the analysis of vapor adsorption on solids is proposed. In this method the adsorption isotherm is represented as a(p) = f(p)/(1-p/ps)d where a(p) is the amount of vapor adsorbed, p is the pressure, ps is the saturation vapor pressure, f(p) is a function describing the adsorption in the first molecular layer, and d is an adjustable parameter. This model allows one to determine the specific surface area of disperse and porous materials in a way that is not limited by the functional form of the monolayer adsorption isotherm, f(p). In addition, this equation gives a new way to correlate adsorption data over the whole range of p /ps. Comparison is made with experimental data for the systems Ar-KCl, N2-KCl, O2-KCl, N2-SiO2, and N2-Al2O3. © 1995 by Academic Press, Inc.