Adsorbents for radioactive cesium

To promote decontamination program of the Cs 137-contaminated soils in the area of Fukushima Daiichi Nuclear Power Plants after the reactor accident, quantitative adsorption data of the adsorbents such as synthesized zeolite A, bentonite, ferrocyanide-Ti(IV) and -Ti(III), montmorillonite, synthesized saponite, etc for alkali metal ions (mmol/g) were studied. A 10 ml solution of alkali metal ions (Cs⁺, K⁺, Na⁺ and Li⁺ ions) containing 0.1 g of the adsorbent was stirred for 10 min and decrease in the concentration of each ions determined by ion-chromatography. Pre-treatment of absorbents with NaCl or HNO₃ was also investigated to conclude that the most effective adsorbent for selective removal of cesium ions among studied is montmorillonite. (S. Ohno)