Selective Removal of Cesium from Sodium Nitrate Solutions by Potassium Nickel Hexacyanoferrate-Loaded Chabazites

Abstract

Abstract Potassium nickel hexacyanoferrate(II)s (KNiFC) were incorporated in the porous matrix of chabazite by successive impregnation with Ni(NO3)2 and K4Fe(CN)6. The loading percentage of KNiFC crystals on chabazite increased with repeated times of impregnation. The ion-exchange equilibrium of Cs+ in KNiFC-loaded chabazite (CFC) was attained within 2 days. Relatively large distribution coefficients of Cs+, K d,Cs, above 104 cm3/g were obtained, irrespective of coexisting NaNO3 concentration. There is a large difference between the K d value of 137Cs and those of other nuclides; the separation factor of Cs/Sr (αCs/Sr = K d,Cs/K d,Sr) was estimated to be above 104. The breakthrough curve for Cs+ through the column packed with CFC exhibited a symmetrical S-shaped profile, and this exchanger proved to be effective for the selective removal of radiocesium from waste solutions containing highly concentrated NaNO3. ACKNOWLEDGMENTS The authors express appreciation to Mr. T. Kamaya and Mr. Y. Sato (Tohoku University) for their helpful discussions of SEM and EPMA data.