The selective removal and fixation of Cs and Sr have been studied in zeolite A and chabazite. Cesium ion was preferentially distributed into chabazite with a high distribution coefficient (KCS>103 cm3 g–1) in the presence of NaCl (10–1 mol dm–3). The KSr values for zeolite A attained about 103 cm3 g–1 in the pH range of 8˜10, and they gradually decreased with an decrease in pH. The initial rate of Cs adsorption was fairly fast in chabazite, and the adsorption ratio reached almost 100% within a few hours. The adsorption ratio of Sr in binderless A zeolite reached almost 100% after 15 h. The adsorption of Cs and Sr on these zeolites was followed by Langmuir-type isotherm. Cesium forms of these zeolites recrystallized to pollucite (CsAISi2O6) above 900°C for zeolite A and above 1,200°C for chabazite. As for Sr forms, these zeolites changed to SrAl2Si2O8 above 900°C. These recrystallized phases were suitable hosts for the immobilization of Cs and Sr in the nuclear waste solutions.
|ジャーナル||journal of nuclear science and technology|
|出版ステータス||Published - 1985 4月|
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