Experimental adsorption studies on different materials selected for developing a permeable reactive barrier for radiocesium retention

Abstract

Cs-137 was accidentally spilled in an industrial waste repository located in a salt marsh in southern Spain, and a pem1eable reactive barrier was proposed to retain it. Cs adsorption properties of di!Terent natural clayey materials were analyzed. The salt marsh waters show high salinity and high chemical variability, therefore Cs adsorption was also analyzed in the presence ofcompelitive ions, especially K+ and NH;. Cs adsorption was non-linear in all the analyzed materials, indicating more than one adsorption siles with different selectivity. lt was shown that in mixed clay systems with illite, montmorillonite and kaolinite. The presence of illite favors Cs retention at low and medium Cs loadings and montmorillonite at high Cs loadings. In the presence of illite and montmorillonite, kaolinite plays almost no role in Cs retention. The presence of K+ and NH4+ significantly hinders cesium adsorption.