Adsorption of barium on kaolinite, illite and montmorillonite at various ionic strengths

Abstract

Summary The sorption behaviour of Ba2+ in three different clay minerals from various regions of Turkey has been investigated by means of a tracer technique using 133Ba in batch experiments. Sorption of Ba2+ on montmorillonite, kaolinite and illite has been studied in mixed solutions of BaCl2 and NaCl at ionic strengths ranging from 1×10-3M to 1×10-1M. The L-shape exchange isotherms for Ba2+-Na+ systems are well defined by a Langmuir type equation. The exchange capacity of Ba2+ ions for all three clay minerals increased with decreasing ionic strength. The adsorption data were fitted to a Freundlich isotherm and empirical Freundlich parameters enabled to the generation of a site distribution function. The selectivity coefficients were nearly constant at low Ba loading and decreased as loading increased. This behavior was an indication of an ion exchange process between Ba2+ and Na+ ions.