STUDY ON REMOVAL OF CESIUM FROM CONTAMINATED SOIL BY ELECTROPHORESIS USING POTASSIUM ACETATE AS ELECTROLYTE

Abstract

9 years have passed since a large amount of radioactive materials were diffused by the nuclear accident at the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company. The decontamination works have almost been completed, and some of the contaminated soil whose topsoil was stripped and collected was transported to the intermediate storage and incineration facilities. However, the contaminated soil containing the radioactive cesium stored in the temporary storage place has not decreased significantly. Additionally, the transportation of the intermediate storage and incineration facilities have an agenda from the viewpoint of cost. Therefore, it is needed to investigate the method of decontamination by which the radiation dose of contaminated soil can be reduced below 8000 Bq/kg at the temporary storage place. Considering the decontamination in the actual temporary storage place, electrophoresis is the simple method as a decontamination method, and it is desirable to utilize zeolite with ion-exchange property as an inexpensive adsorbent. Ammonium acetate has been considered to be effective as an electrolyte because it has ammonium ion that has high ion-exchange reaction with cesium ion. However, an efficient decontamination cannot be achieved since the adsorption of cesium ions to zeolite is inhibited by ammonium ions. The purpose of this study is to discuss the efficient removal of cesium by using zeolite as an adsorbent and potassium acetate as an electrolyte through the electrophoresis test. From the test results, it is turned out that potassium acetate is suitable to extract cesium efficiently in electrophoresis.