Interpenetrated network hydrogel with dual ion active sites for radioiodine (I−, IO3−) removal

Radioiodine anions (I and IO 3 ) pose a serious threat to the environment and human health due to their high radioactivity and solubility. Therefore, it is important to develop efficient and economical adsorbent materials for radioiodine anions. In this work, combined with the excellent properties of chitosan (CS) and (3-acrylamidopropyl) trimethylammonium chloride (AMPTAC), a novel interpenetrating network hydrogel CS@AMPTAC was synthesized to improve the adsorption efficiency of CS hydrogel for I and IO 3 . Due to the electrostatic interaction and anion exchange ability of the quaternary ammonium group (−N + (CH 3 ) 3 Cl⁻), the introduction of AMPTAC constructs a more complex and effective adsorption sites for CS@AMPTAC. Combined with the protonated amino group (−NH 3 + ) in CS, the CS@AMPTAC showed better adsorption efficiency and anti-interference performance than CS. The CS@AMPTAC hydrogel shows excellent adsorption performance over a wide pH range (pH 2–11), which overcomes the sensitivity of traditional adsorbents to pH. Meanwhile, the maximum adsorption capacities of CS@AMPTAC for I and IO 3 are 359.9 mg/g and 312.64 mg/g, respectively, which exhibits remarkable enhancements of 246.26 mg/g and 267.34 mg/g compared to CS. In addition, based on the synergistic adsorption mechanism and the hydrophilicity of CS@AMPTAC, the hydrogel can reach adsorption equilibrium within 30 min. The synergic strategy shows great potential for application in the treatment of radioiodine anions.