Cuprous Oxide-Based Cationic Hydrogel by the Integration of Enrichment and Immobilization of Radioiodine (I–, IO3–) in Aqueous Solution

The efficient capture and immobilization of radioiodine (I-, IO3-) is of great importance in radioactive waste management. Here, a Cu2O-loaded three-dimensional bulk cationic hydrogel composite (Cu2O@CH) was successfully prepared by simple redox reactions and UV photopolymerization, which realized the rapid enrichment and efficient immobilization of I- and IO3-. The adsorption experiments showed that the maximum adsorption capacity of Cu2O@CH for I- in the solution at pH = 3 reached 416.5 mg/g, and the adsorption capacity of IO3- in the solution at pH = 6 could reach 313.4 mg/g. It exhibited extremely fast adsorption kinetics for I- and IO3-. In addition, Cu2O@CH also exhibited efficient I- and IO3- removal from simulated high-level liquid waste. The rapid capture and effective immobilization of radioiodine (I-, IO3-) were realized by the electrostatic interaction of -N+(CH3)3 groups in Cu2O@CH with I- and IO3-, as well as the chemical reactions between Cu2O and I-. The bulk cationic hydrogel composite explored the multifunctional role toward fast, high adsorption capability and easy handling, highlighting its superiority compared to the powder adsorbent, which renders it a potential adsorbent for the removal of radioactive iodine (I-, IO3-) in nuclear wastewater treatment.