SORPTION OF CESIUM IN CONTROLLED LANDFILL LEACHATE BY NATURAL MINERALS: ZEOLITE, ILLITE, AND VERMICULITE

Abstract

 A part of wastes containing radiocesium which was spreaded to the environment by the accident at Fukushima Daiichi nuclear power plant have been disposed in controlled landfill sites. The objective of this study was to examine the usage of natural minerals; three types of zeolite, two types of illite, and vermiculite, as a Cs adsorbent to prevent Cs from leaking with leachate from the controlled landfill site. The results of a sorption test using actual leachate showed that Cs sorption ratio did not depend on Cs concentration in leachate for zeolite, but illite and vermiculite could sorb Cs more efficiently at lower Cs concentration in leachate. Additionally, the amount of sorbed Cs has a high correlation with cation exchange capacity. The results of an extraction test showed that all of the minerals, especially zeolite, had high Cs fixation capacity. Since there was a high correlation between Cs fixed fraction and Radiocesium Interception Potential (RIP), it was suggested that Cs fixation capacity can be estimated using RIP.