Crossed-linked chitosan coated cuprous oxide microspheres for iodide adsorption via one-step in-situ generation

Radioactive iodine waste generated from nuclear power and radioactive medical treatments has become a serious environmental issue, raising concerns about public health. Cross-linked chitosan adsorbed iodide anions through electrostatic attraction yet limit-efficiently. To achieve better adsorption performance, chitosan-coated cuprous oxide microspheres (Cu₂O@CM) was proposed via one-step in-situ liquid-phase method. Both Cu₂O@CM-e cross-linked with epichlorohydrin and Cu₂O@CM-g cross-linked with glutaraldehyde, performing rough and spherical morphology, exhibited rapid iodine removal capacities of 0.1843 mmol/g for Cu₂O@CM-e and 0.1819 mmol/g for Cu₂O@CM-g within just 10 min. The adsorption process occurred through a combination of physical multilayer adsorption and chemical monolayer adsorption, driven spontaneously and endothermically. After four regeneration cycles, Cu₂O@CM-e and Cu₂O@CM-g maintained almost identical adsorption efficiencies, highlighting their reusability. Considering the interference of Cl⁻ and CO₃²⁻, both adsorbents showed significant selectivity towards competing ions. Thus, both adsorbents showed promising potential for the removal of iodine waste