Preparation of Insoluble Ferrocyanide(KNiFC)-Loaded Silica Gels and Adsorption Properties for Cesium

Potassium nickel hexacyanoferrate (II) (KNiFC)-loaded silica gels were prepared by successive impregnation of macro pores with Ni(NO_3)_2 and K_4Fe(CN)_6 solutions. The loading precentage of KNiFC increased with impregnation cycles, and the KNiFC precipitates uniformly dispersed in macro pores of the matrix. The uptake of Cs^+ on KNiFC-loaded silica gels attained equilibrium within 7d at batch factor of 700(cm)^3/g, and relatively large distribution coefficients of Cs^+, K_, above (10)^4(cm)^3/g, were obtained even in the presence of 5M NaNO_3. The KNiFC particles were thermally decomposed above 300℃, resulting in lowering of uptake ability for Cs^+. This exchanger proved to be effective for the selective removal of radioactive cesium from waste solutions containing highly concentrated NaNO_3