Interlamellar sorption of ethanol on montmorillonite clays with different layer charges

Abstract

The shape of the adsorption isotherms of ethanol on montmorillonite clays results from the combined effect of adsorption at the external surface, the formation of interlamellar complexes and capillary condensation. The formation of interlamellar complexes depends on the charge density distribution of the clay lamellae. Samples having a large proportion of layers with a low charge density expand to a great extent in a narrow range of low vapour pressures. This results in stepwise adsorption isotherms. In samples having a large proportion of layers with a high charge density, expansion is extended over a wide range of relative vapour pressures. In that case the adsorption isotherm contains no steps.