In vitro Study of 137Cs Sorption by Hexacyanoferrates(II)

Abstract

We synthesized a varicty of colloidal and non-colloidal mixed hexacyanoferrate(II) complexes of Fe. Cu. Co. Ni. Zn. Mn and studied ihe cesium Sorption in vitro under physiological conditions (artificial gastric juice. pH 1.2 and artificial duodenal juice. pH 6.8). All of the hexaeyanoferrates under study (except cesium iron(III) hexaeyanoferrate CsFeHCF) sorb tracer amounls of 13 Cs quantitatively. Differences in the sorption capacity become obvious by offering substantial amounts of cesium. Potassium copper hexacyanoferrate(II) (KCuHCF) and potassium zinc hexa- cyanoferrate(II) (KZnHCF) are most efficient in cesium sorption at pH 1.2 and at pH 6.8. The sorption capacities of KCuHCF and KZnHCF (2.3-3.0 mmol Cs'g HCF) are twice as high as for coiloidai Prussian blue (KFeHCF; 1.0-1.3 mmol Cs/g HCF) and insoluble Prussian blue (FeHCF: 1.0-1.6 mmol Cs/g HCF). The most promising Compounds. KCuHCF and KZnHCF. should be further investigated in in vivo studies for 137 |l4cesium decorporation. Evidence indicate that the sorption mechanism for most of the Compounds under study is a cesium/potassium ion-exehange reaction. In the case of insoluble Prussian blue (FeHCF). a cesium/proton exchange was observed. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ On laboratory scale. 137 |V4Cs-contaminated whey dry powder. produced from South German cow milk in summer 1986 was almost completely decontaminated by dialysing a whey Suspension against buffer Solution containing FeHCF. The 117 "JCs'-ions. completely bound by FeHCF. can be isolatcd from the buffer Solution by simple filtration. The buffer Solution and the FeHCF can