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 SO42‐, 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.