Thin Solid Films. 88 (1982) 313-379 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFE GENERAL FILM BEHAVIOUR zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDC 373 ADSORPTION OF MIXTURES OF METHANE AND KRYPTON ON CaA ZEOLITE I: ANALYSIS OF THE ADSORPTION DATA USING A FREUNDLICH- TYPE EQUATION DERIVED FOR CONSTANT MOLE FRACTIONS OF COMPONENTS IN THE ADSORPTION SPACE M. BiiLOW (Received August 24, 1981; accepted September 17, 1981) The experimental data for the adsorption of mixtures of methane and krypton on CaA-type zeolite, measured at a constant composition of the adsorption space, are interpreted using a Freundlich-type equation. The parameters of Freundlich’s isotherm are determined for methane and for krypton. The temperature de- pendences of the Freundlich parameters are also investigated. 1. INTRODUCTION Most of the well-known isotherm equations for the adsorption of binary gas mixtures on solids have been derived by assuming that the difference between the adsorption energies of the two components is the same for all type of adsorption site1.2. This means that the energy distribution functions for the components have identical shapes and are shifted on the energy axis only. When a constant difference between the adsorption energies is assumed, the mixed-gas adsorption isotherms are derived in a similar manner to the single-gas isotherms. Recently, Btilow et al3 have derived mixed-gas adsorption isotherms by assuming the mole fractions of both components to be constant in the adsorption space. They also assumed that the mole fractions were equal for all types of adsorption site. These isotherm equations are particularly useful for analysing mixed-gas adsorption data measured at constant mole fractions of components in the adsorption space. In this paper we discuss the application of Freundlich’s equation to a description of the adsorption data for mixtures of methane and krypton on CaA zeolite; these data were obtained for constant mole fractions of components in the adsorption space. An analysis of the temperature dependence of the adsorption parameters is also presented. 2. THEORY According to the theory developed by Billow et aL3, the classical Freundlich 0040-6090/82/0000-0000/$02.75 (0 Elsevier Sequoia/ Printed in The Netherlands