Sorption of caesium by complex hexacyanoferrates iii. a study of the sorption properties of potassium copper ferrocyanide

Commercially available potassium copper ferrocyanide (KCuFC) has been studied for caesium sorption. An effective capacity of 2.25 ± 0.06 mmol g−1 can be achieved at a caseium concentration of 0.015m. The presence of 0.82m, magnesium nitrate reduces the effective capacity to 2.04 ± 0.06 mmol g−1. The cyanoferrate also shows high caesium uptake in various simulated process solutions relevant to the treatment of radioactive wastes. KCuFC also possesses a high selectivity for caesium in high salt concentration solution. However, the cyanoferrate is not stable in acidic solution of pH < 3. Desorption of the sorbed caesium at various nitric acid concentrations has been investigated and it is concluded that caesium is eluted by a chemical reaction step as a consequence of the oxidation of the cyanoferrate.