Sorption behavior of cesium onto bentonite and sedimentary rocks in saline groundwaters

Kitamura, Akira  ; Tomura, Tsutomu*; Sato, Haruo; Nakayama, Masashi 

Distribution coefficient of cesium onto bentonite and sedimentary rocks was determined in saline groundwaters. Distribution coefficient of cesium onto the solid phases was also determined in sodium chloride and potassium chloride solutions in order to elucidate sorption behavior of cesium. It was expected that the sorption behavior of cesium was regarded as ion exchange reactions with sorption sites of the solid phases from the results of dependencies of distribution coefficient on pH and ionic strength. It was found that only potassium ion was competed with cesium for the sorption onto sedimentary rocks, while both sodium and potassium ions was competed with cesium for the sorption onto bentonite. It was also found that sorption behavior of cesium onto sedimentary rocks was well described using a model on the sorption of cesium onto illite. The present study was performed in Tokai Works, Japan Nuclear Cycle Development Institute (one of the predecessors of JAEA) in FY 2002-2003.