SELECTIVE REMOVAL OF CESIUM FROM HIGHLY CONCENTRATED SODIUM NITRATE NEUTRAL SOLUTIONS BY POTASSIUM NICKEL HEXACYANOFERRATE(II)-LOADED SILICA GELS

Abstract

ABSTRACT Potassium nickel hexacyanoferrate(II) (KNiFC)-loaded silica gels were prepared by successive impregnation of macro pores with Ni(NO3)2, and K4Fe(CN)6 solutions. The KNiFC precipitates uniformly dispersed in the matrix of silica gel, and the loading percentage of KNiFC increased with the number impregnation cycles. The uptake of Cs+ on KNiFC-loaded silica gels (SLFC) attained equilibrium within 2 d, and relatively large distribution coefficients of Cs+, Kd,cs, above 104 cm3/g, were obtained even in the presence of 5 M NaNO3. The ion exchange of K+ Cs+ in SLFC followed a Langmuir-type isotherm and the maximum uptake amount of Cs+ was estimated to be 0.305 mmol/g. The breakthrough curve of Cs+ through a column packed with SLFC exhibited a favorable S-shaped profile. This exchanger proved to be effective for the selective removal of radioactive cesium from neutral waste solutions containing highly concentrated NaNO3.