[2G05-09] Treatment of Contaminated Water and Secandary Waste 2

[2G05] Rapid Removal of Cesium from Fukushima Contaminated Soil by Hydrothermal Treatment with Multivalent Cations

*Xiangbiao Yin¹, Yoshikazu Koma¹, Yusuke Inaba², Kenji Takeshita² (1. Japan Atomic Energy Agency, 2. Tokyo Institute of Technology)

Keywords:Cesium, Clay Minerals, Soil decontamination, Volume reduction, Cation exchange

After the Fukushima accident, radioactive Cs was widely dispersed and contaminated the north-eastern district of Japan, thus the topsoil has been stripped within the top 5 cm which is now just being stored in temporary storage sites because of its difficulty of decontamination. So it is urgently essential to develop more environmental friendly and efficient techniques performing desorption of Cs⁺ ions from the clay soils.

The hydrothermal treatment (HTT) process is a newly testing method to desorb Cs from the clays/soils using the subcritical water (SCW) at high temperature. This process is much attractive because of its safety, accessibility, no any secondary waste and low cost. In our study, we clarified the effect of cation species and temperature dependence on the Cs desorption from a 2:1 clay mineral, elucidated the desorption process and discussed the mechanism.