The Ion-Exchange Property of Some Layered Inorganic Materials with Potassium Ion, Rubidium Ion and Cesium Ion, and Selective Cesium Ion-Exchange of Synthetic Mica

Abstract

Abstract The ion-exchange property of sodium difluorotetrasilicate, Na-TSM, with potassium, rubidium and cesium ions was investigated in addition to two other typical layered inorganic materials. The selectivity sequence of Na-TSM was Cs+ > Rb+ > K+ and the selectivity difference of Na-TSM was highest among the examined layered materials. It was found from a chemical analysis that cesium ion-exchange participated in magnesium ions, which is a lattice component of Na-TSM, in addition to an ordinary ion-exchange reaction with the interlayer sodium ions. The exchange of cesium ions with magnesium ions was found to be stoichiometric, and was expected to be an ideal ion-exchange reaction. It was a peculiar phenomenon only on Na-TSM. Once cesium ions were exchanged in a Na-TSM lattice, they were hardly released, due to a reverse ion-exchange with sodium ions. The highest selectivity difference and tight binding of cesium ions were interpreted by an ion-exchange with lattice magnesium ion as well as decreased dehydration, which resulted in the interlayer gallery height.