Equation of the Sorption Isotherm on Zeolite Y Including Heterogeneity of the Sorbent: A Novel Modification

Abstract

The complex character of water vapour sorption on zeolite Y has been demonstrated. It has been found that the assumptions of the Dubinin theory of volume filling of micropores (TVFM) are applicable to the description of such water vapour sorption. An equation for the adsorption isotherm is given which describes the experimental data in a satisfactory manner and which includes both the heterogeneity of the zeolite surface and the size distribution of the micropores participating in the sorption process. The equation yields realistic values of the total micropore volume which are close to the experimental sorption capacities. A significant effect of the sodium counterions on the sorption of water vapour has been found.