Fundamental study on extraction of cesium from soil

抄録

Large amounts of radioactive materials were spread over a wide range by the accident of Fukushima Daiichi nuclear power plant occurred on March 11, 2011. Currently, the decontamination of radioactive materials discharged by this accident is urgently needed. However, the efficient and effective decontamination technology is not established. The current state is that the completion of final decontamination is nowhere in sight because the disposal volume is enormous. It is necessary to achieve the extraction of the cesium that firmly fixed to the clay mineral in soil and the volume reduction of the disposal materials so as to base our prediction on the decontamination. The authors focus attention on the fact that the cesium is solubility and exists as a monovalent cation in the solution. Through the fact, the method that the cesium ion in soil migrates to the cathode plate connected with the negative side if a DC power supply due to electrophoresis and is captured by the adsorbent placed between the soil and the cathode plate is proposed. First, in this study, the test with a small chamber was conducted to examine the extraction characteristic of cesium and the adsorption property of an adsorbent material. Secondly, the adsorption property of the adsorbent material for cesium through the electrophoresis adsorption test was investigated by more practically test with a large-scale chamber which is extended from the test with a small chamber. From the test with a small chamber, it is turned out that there is not most changes in extraction characteristics even if the passage of time is changed, and that the used adsorbent has a very high adsorption ability. From the test with a large-scale chamber, it is found that the adsorption effect of the large-scale test is inferior to the small one due to the decrease of energizing performance.