Eco-friendly one-pot synthesis of Prussian blue-embedded magnetic hydrogel beads for the removal of cesium from water

Abstract

A simple one-step approach to fabricating Prussian blue-embedded magnetic hydrogel beads (PB-MHBs) was fabricated for the effective magnetic removal of radioactive cesium (137Cs) from water. Through the simple dropwise addition of a mixed aqueous solution of iron salts, commercial PB and polyvinyl alcohol (PVA) to an ammonium hydroxide (NH4OH) solution, the formation of hydrogel beads and the encapsulation of PB in beads were achieved in one pot through the gelation of PVA with in situ-formed iron oxide nanoparticles as the cross-linker. The obtained PB-MHBs, with 43.77 weight % of PB, were stable without releasing PB for up to 2 weeks and could be effectively separated from aqueous solutions by an external magnetic field, which is convenient for the large-scale treatment of Cs-contaminated water. Detailed Cs adsorption studies revealed that the adsorption isotherms and kinetics could be effectively described by the Langmuir isotherm model and the pseudo-second-order model, respectively. Most importantly, the PB-MHBs exhibited excellent selectivity for 137Cs in 137Cs-contaminated simulated groundwater (55 Bq/g) with a high removal efficiency (>99.5%), and the effective removal of 137Cs from real seawater by these PB-MHBs demonstrated the excellent potential of this material for practical application in the decontamination of 137Cs-contaminated seawater.