Adsorption on transition metal sulphates and adsorbent crystal field effects

Abstract

The adsorption of CFCl₃ on the anhydrous transition metal sulphates, manganese through zinc, with the exception of ferrous sulphate, has been studied at 20.0, 6.0 and –10.0°C. The differential entropy of adsorption suggests that CFCl₃ behaves as a two-dimensional van der Waals gas on all the adsorbents. The isosteric heat of adsorption at zero surface coverage was greatest with those adsorbents having the largest crystal field stabilization energy. Attempts to predict a crystal field contribution to the heat of adsorption, based on assumed surface structures, has provided qualitative agreement with experiment.