Collect. Czech. Chem. Commun. 1992, 57, 1201-1209

BET Adsorption Isotherm and Surface Heterogeneity

Lydia Ethel Cascarini de Torre and Eduardo Jorge Bottani

Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Castilla de Correo 16 Sucursal 4, RA-1900, La Plata, Argentina


The BET adsorption isotherm is modified in order to take account of surface heterogeneity. The adsorption isotherm is obtained following the statistical mechanics formalism, proposed by Steele, and the effect of surface heterogeneity is limited to the first layer. A Gaussian adsorption energies distribution function is used to describe surface heterogeneity. The variations of the C parameter, multilayer formation and the inversion of adsorption isotherms are analysed.