Sorption of cesium on ferrocyanide sorbents from highly saline solutions

Abstract

Sorption of microamounts of Cs from highly saline solutions (bottom residues from nuclear power plants) on various types of ferrocyanide sorbents was studied. The dependences of the distribution coefficient (Kd) of 137Cs on pH of solution were determined under static conditions. They strongly depend on the type of the sorbent used. FS-2 sorbent prepared by joint precipitation of silicic acid and copper ferrocyanide exhibits the best sorption characteristics toward Cs. On this sorbent, Kd of 137Cs in a model solution with pH 11, the Cs sorption drastically decreases because of dissolution of the ferrocyanide component of the sorbent. Data on Cs sorption under dynamic conditions on various types of ferrocyanide sorbents from the bottom residue with pH 8–11 are presented. The volume of the solution passed up to 1% 137Cs breakthrough was determined. FS-2 sorbent exhibits the best dynamic characteristics. Its use allows decontamination of 1000–4500 column volumes of the bottom residue depending on pH.