Amino-functionalized magnetic chitosan beads to enhance immobilization of potassium copper hexacyanoferrate for selective Cs removal and facile recovery.

Potassium copper hexacyanoferrate (KCuHCF)-incorporated magnetic chitosan beads (HMC) were synthesized for both selective Cs removal in aqueous solutions and facile recovery of the spent adsorbent. To disperse and immobilize large amounts of the KCuHCF, methyl acrylate and diethylenetriamine were sequentially grafted onto the one-step synthesized magnetic chitosan beads. The additional introduction of amino functionality led to the enriched Cu ions on the bead surface to incorporate KCuHCF into the grafting matrix. Consequently, the HMC exhibited a high Cs capacity calculated to be 136.47 mg g from the Langmuir model, and the equilibrium was established within 4 h. Moreover, the HMC exhibited excellent stability in a wide pH range from 4 to 11 and an outstanding Cs selectivity (>97%) in seawater (1.11 mg L Cs). From a practical point of view, the HMC was stable during five successive adsorption cycles and easily recovered by magnets, enabling continuous operation to decontaminate a large volume of wastewater.