Synthesis and Cs-adsorption behavior of phyllosilicates in saponite-phlogopite system

山田 裕久*; 横山 信吾*; 渡辺 雄二郎*; 森本 和也*; 鈴木 伸一; 矢板 毅; 八田 珠郎*

no journal, , 

As the result of Fukushima Daiichi Nuclear Power Plant accident, the natural environment, especially soil, was widely contaminated with radioactive Cs. Phyllosilicates play the important roles for the remediation of the contaminated soil. Several phyllosilicates were prepared at hydrothermal conditions of 300 - 800 C and 100 MPa, which were characterized by XRD, SEM and TEM. The selected products were investigated for Cs adsorption behavior by changing the initial concentration of Cs in a solution. The results indicated that the formation of trioctahedtral phyllosilicates were clearly dependent on synthetic temperature and chemical composition. Above 500 C, the high crystalline saponite, which layer charge was up to 1.2, was obtained. Vermiculite with high-crystallinity was also formed above 500 C, which layer charge was up to 2. The high Cs adsorption ability of synthetic saponite and vermiculite was confirmed in distilled water. The relationship between the Cs adsorption ratio and the initial Cs concentration in the solution clearly indicated that Cs adsorption behavior was well correlated with the amount of layer charge in smectite and vermiculite. Results confirm that phyllosilicates with high layer charge should be important for Fukushima-problem.