Seaweed‐Inspired “Iodine‐Mediated Iodine Capture” Strategy Enables Sustainable Radioiodine Remediation

Abstract Inspired by seaweed's extraordinary iodine‐accumulating ability, a breakthrough biomimetic “iodine‐mediated iodine capture” strategy for iodine capture is reported using redox‐responsive ionic covalent organic frameworks (iCOFs). Unlike conventional ion‐exchange processes limited by counterion displacement, the approach enables in situ polyiodide chain formation within framework channels, creating self‐reinforcing “iodophilic” domains that fundamentally transform the capture mechanism. The resulting biomimetic iCOFs demonstrate outstanding aqueous iodide capture performance, achieving high adsorption capacities up to 486.1 mg g −1 , with rapid kinetics under the tested conditions (30 min), exceptional selectivity in complex matrices like seawater and salt lake brines, remarkable reusability over 5 cycles without significant capacity loss, and excellent chemical stability in harsh environments. Combined in situ spectroscopic analyses, density functional theory calculations, and molecular dynamics simulations reveal that charge‐transfer interactions between pre‐captured polyiodide species and incoming iodide ions generate highly specific binding sites that accelerate mass transfer. This biomimetic strategy also demonstrates universal applicability across gaseous and organic‐phase iodine capture, with successful membrane‐based continuous flow implementation confirming practical viability. This work establishes a paradigm‐shifting approach offering transformative solutions for both nuclear waste management and valuable iodine resource recovery from natural brines, while providing new design principles for engineering biomimetic functionality into porous materials.