Dynamic Adsorption Behavior for Removal of Cs from Polluted Solution

Since the nuclear accident of March 2011, the damaged nuclear reactors at Fukushima-Daiichi power plant have produced over 50,000 tons of heavily polluted water containing radioactive substances. These substances, including cesium and strontium, must be removed before the polluted water is discharged into public water areas. In this study, the ion-exchange reaction with zeolite was examined as a means to remove radioactive cesium having a half-life of 2-30 years from the polluted water. In order to design an industrial-scale system for consecutive processing of polluted water, the amount and rate of ion exchange with four different types of zeolite obtained by a hydrothermal reaction were compared, and the maximum throughput of the consecutive system was estimated. It was found that 500 dm(3) of polluted water containing cesium ions at 1 ppm (corresponding to 3.2x10(6) Bq/cm(3)) can be processed with 10 g of K-CHA type zeolite. This suggests that it will be possible to remove radioactive cesium from an extremely large amount of polluted water with a consecutive water-processing facility using K-CHA type zeolite.