Recovery of cesium ion from the aqueous solution by the electric occlusion using a porous aluminum electrode

Using stable isotopic cesium with the concentration that simulated the pollution level around the Fukushima Daiichi Nuclear Power Station, the authors examined the occlusion capacity of a porous aluminum electrode based on a beaker-level experiment. A tested aluminum sample was made of metallic aluminum particles having an average particle diameter of 0.2 mm and a porosity of 50%. A cesium standard solution had 4 ppm of cesium chloride concentration, equivalent to 12.86 GBq/L when converted to radioactive cesium. A platinum anode and a porous aluminum cathode were used in the experiment. With occlusion time and applied voltage increased, cesium concentration decreased, reaching the concentration of trace with the applied voltage of 100 V for 90 min for occlusion, and nearly 0 ppm after 120 min. The occlusion capacity of the porous aluminum electrode was unabated even after 20 times of repetitions, exhibiting a high durability. The elution amount of the occluded cesium was 2.1% through washing, and 0.16% after reverse voltage added, which proved the effectiveness of the porous aluminum electrode. A similar effect was confirmed even in strontium. (A.O.)