Record High Iodate Anion Capture by a Redox‐Active Cationic Polymer Network

As a critical radioactive anionic contaminant, traditional adsorbents primarily remove iodate (IO₃ ^-) through ion exchange or hard acid-hard base interactions, but suffer from limited affinity and capacity. Herein, employing the synergistic effect of ion exchange and redox, we successfully synthesized a redox-active cationic polymer network (SCU-CPN-6, [C₉H₁₀O₂N₅ ⋅ Cl]_n) by merging guanidino groups with ion-exchange capability and phenolic groups with redox ability via a Schiff base reaction. SCU-CPN-6 exhibits a groundbreaking adsorption capacity of 896 mg/g for IO₃ ^-. The inferior adsorption capacities of polymeric networks containing only redox (~0 mg/g) or ion exchange (232 mg/g) fragments underscore the synergistic "1+1>2" effect of the two mechanisms. Besides, SCU-CPN-6 shows excellent uptake selectivity for IO₃ ^- in the presence of high concentrations of SO₄ ^2-, Cl^-, and NO₃ ^-. Meanwhile, a high distribution coefficient indicates its exemplary deep-removal performance for low IO₃ ^- concentration. The synergic strategy not only presents a breakthrough solution for the efficient removal of IO₃ ^- but also establishes a promising avenue for the design of advanced adsorbents for diverse applications.