(180d) Potassium Copper Hexacyanoferrate-Embedded Doubly-Crosslinked Magnetic Hydrogel for Effective Cs+ Removal and Facile Recovery

As the danger for radioactive materials is highlighted, decontamination capability is highly demanded. For selectively remove Cs⁺ ions in radioactive wastewater, we synthesized potassium copper hexacyanoferrate (KCuHCF)-immobilized magnetic hydrogel beads (HCF-Mbead). The polymeric matrix was efficiently crosslinked via both Fe³⁺ binding and freeze-thaw to enhance mechanical stability. A hierarchical pore structure of HCF-Mbead facilitated rapid access of Cs⁺ to ion-exchangeable sites of KCuHCF. As a result, the HCF-Mbead exhibited a high cesium adsorption capacity of 69.2 mg g^-1 and selectivity (K_d = 4 × 10⁴ mL g^-1, 1 ppm Cs⁺ in seawater), and it was stable in a wide range of pH (3-11). Furthermore, it could be easily recovered by magnet after the adsorption process. This study enables rapid recovery of spent adsorbent in addition to selective Cs⁺ adsorption in case of serious accidents.