(583d) Cesium Removal By Immobilization of Potassium Copper Hexacyanoferrate in a Cellulose-Hydrogel Network

Treatment of radioactive wastewater has become important due to an enormous amount of nuclear waste and the potential uncontrolled release. For adsorption of radioactive cesium, potassium copper hexacyanoferrate (KCuHCF) was immobilized in a functionalized cellulose hydrogel. The encapsulation by the cellulose-based hydrogel can solve the applicability problem of KCuHCF caused by sub-micron sized particles, and the superabsorbent property improved the adsorption kinetics. KCuHCF-cellulose hydrogel composites (HCF-gels) exhibited rapid Cs⁺ recovery with 90% removal of 20 ppm Cs⁺ in 1 h. They also exhibited high cesium capacities of 274-308 mg/g, which was attributed to the abundant sorption sites in the carboxymethyl cellulose. Moreover, the HCF-gels were stable and could adsorb cesium ions sufficiently in a wide range of pH (3-10). Remarkably, the HCF-gels could adsorb Cs⁺ ions selectively (>90%) even in seawater condition which contains highly concentrated other cations such as Na⁺ and Mg²⁺. The excellent cesium removal performance comes from the high accessibility of hydrogel property and the well-dispersed ion-exchanger particles in the composites.