Effect of layer charge on fixation of cesium ions in smectites

In order to rationalize the influence of layer charge on cesium fixation in smectite, remaining Cs+ or Na+ in cesium- or sodium-saturated smectite specimen (Cs- or Na-specimen), respectively, were examined after Ba2+ exchange using a tracer method. The location of sorbed Cs+ in smectite was also studied by X-ray photoelectron spectroscopy (XPS). A linear multiple regressive model has been used to formulate a relation between the amount of cesium left after Ba-exchange of Cs- specimen and the layer charge characteristics. A good correlation between the amount of remaining Cs and octahedral charge was observed for the Cs-specimen whereas for Na-specimen there was no viable change. From the analysis of the chemical states of sorbed-Cs by XPS, two sorption sites were proposed for the Cs-specimen.