Exchange adsorption of strontium ion by calcined montmorillonite

A new swellingless and large particle exchanger was prepared by calcination of bentonite which belongs to a representative of montmorillonite group, and its adsorbability for strontium ion has been examined. The calcination is not affective to the exchange capacity up to 500℃, however, it decreases with the rise of calcination temperature above 500℃. The rate of the decrease in its capacity was maximum in the exchanger treated with sodium hydroxide. There was not found a simple relation between the concentration of acid and the rise of the capacity, on the other hand, there is a semi-logarithmic relation between the concentration of sodium hydroxide and the capacity. Only Na-form exchanger except Natural- and H-form can be used in column for the removal of strontium, because both latter have very low capacity for it. It is concluded that Natural-form bentonite had selectivity for cesium ion as the result of very low capacity for strontium comparing with cesium. However, montmorillonite is possible to have a high capacity for strontium corresponding to cesium in the treatment with sodium hydroxide. (author)