INVERSED SELECTIVITY SERIES FOR ADSORPTIO N OF ALKALI-METAL CATIONS AT SIDE FACES OF LAYER ALUMO SILICATE CRYSTALS

Adsorption of alkali metal cations at side faces of montmorillonite an d kaolinite crystals is shown to be described by inversed selectivity series. The results obtained are compared with the data concerning the adsorbability of alkali metal cations at silica gel for neutral and h igh pH values, and also at aluminium oxide and gematite at pH values w hich exceed their corresponding isoelectric points. Which adsorbabilit y series actually takes place, direct or inversed, depends on the conc entration of ions which determine the potential of mineral ion exchang er surface, and also on the contribution of electrostatic repulsion be tween neighbouring cations into total energy of their adsorption at th e ion exchanger.