Immobilization of potassium copper hexacyanoferrate in doubly crosslinked magnetic polymer bead for highly effective Cs+ removal and facile recovery

A potassium copper hexacyanoferrate (KCuHCF) embedded magnetic hydrogel bead (HCF-Mbead) was synthesized via a facile double crosslinking methods of Fe3+ ionic binding and freeze-thaw for effective Cs+ removal. The HCF-Mbead had a hierarchical porous structure facilitating fast access of Cs+ ions to embedded active sites. The adsorbent showed enhanced Cs+ removal properties in terms of capacity (69.2 mg/g), selectivity (Kd = 4 × 104 mL/g, 1 ppm Cs+ in seawater) and stability (>99.5% removal in pH 3 ∼ 11) with rapid magnetic separation. This study further opens the possibility to develop an efficient material that links the integration of adsorption and recovery.