Development of decontamination technique for radioactive Cs in soil using composite material of Na-P1 type zeolite and magnetite

Na-P1 type zeolite is a porous material with its pore opening size similar to the diameter of Cs+, and has considerably high adsorption selectivity for Cs+. In Fukushima, we conducted experiments to remove radioactive Cs from some soils, by using magnetized Na-P1, a composite of magnetite and Na-P1. By mixing soil with the magnetized Na-P1, with the mass ratio of 10:1, in ammonium oxalate solution for 10 min, more than 80% of radioactive Cs was removed from soil. Important factors for the successful removal of radioactive Cs from soils were preparation of soil composite with no separation of magnetite and Na-P1 during the mixing, optimization of the structure of magnetic separator which separate soil and magnetized Na-P1, and the selection of solution in the mixing procedure. (author)