Removal of 60Co and 137Cs from simulated NPP trap waters

Abstract

The possibility of removing 60Co and 137Cs from simulated NPP trap waters by sorption and precipitation methods was examined. The use of layered double hydroxides (LDHs) of Mg and Nd, containing CO32− in the interlayer space, for removing 60Co from NPP trap waters is inefficient, especially in the presence of EDTA. After 2 h of contact of the solid and liquid phases, the degree of 60Co sorption does not exceed 12% at V/m = 500 mL g−1. Coprecipitation of 60Co with a complex precipitate of Fe3+ and triethylenediamine (CH2-CH2)3N2 from simulated NPP trap waters containing 0.03 M Co2+ allows ∼85% removal of the radionuclide. The 60CO coprecipitation with KFe[Fe(CN)6] from simulated NPP trap waters does not ensure its efficient removal. The degree of coprecipitation of 60CO with KFe[Fe(CN)6] varies from ∼55 to ∼85%. A procedure was suggested for removing 60Co and 137Cs from aqueous solutions by coprecipitation of the radionuclides with the solid phase of K+, Fe3+, and Ni2+ ferrocyanides formed by adding K4[Fe(CN)6], Fe(NO3)3, and Ni(NO3)2 in succession to the solution. The procedure ensures almost 100% removal of both radionuclides from simulated NPP trap waters.