Clay chemistry: Investigation of thermodynamics of ion exchange reactions by titration calorimetry

Abstract

We have built a titration calorimeter that is suitable for measurements on colloidal suspensions as well as more conventional chemical reactions in solution. This calorimeter has been used for investigation of a number of ion exchange reactions involving kaolinite and montmorillonite clays. Results of these measurements have led to cation exchange capacities, to enthalpies of ion exchange reactions, and also to equilibrium constants for some of these same reactions. These calorimetrically determined cation exchange capacities and equilibrium constants agree well with corresponding quantities obtained by way of conventional methods based on chemical analyses. It has been demonstrated that titration calorimetry is a useful and convenient method for investigation of ion exchange in clays.