Porphyrin-Based Hyper-Cross-Linked Polymers as Adsorbents for Reversible Capture of Iodine

Designing a novel adsorbent with high selectivity and absorptive capacity to remove I2 remains a challenging task. In this work, a series of porphyrin-based hyper-cross-linked porous organic polymers (PHCPs) with a dual hydroxy-rich structure were synthesized by the Friedel–Crafts reaction. PHCPs exhibit excellent thermal stability. The incorporation of abundant π-electrons and heteroatoms (N/O) in the PHCPs framework leads to substantial charge transfer interactions with iodine, resulting in a high adsorption capacity (469 mg g–1) and rapid adsorption. Moreover, the adsorption dynamics of PHCPs for iodine in both aqueous and cyclohexane solutions follow a pseudo-second-order kinetic model, and the adsorption isotherm model complies with the Freundlich model. Importantly, PHCPs selectively capture I3– in the presence of anionic competition and effectively capture iodine at different pH values. Additionally, the volatile iodine capture performance of PHCPs reached 623 wt %. This study highlights the extensive application prospects of PHCPs in the removal of iodine from both the gas and liquid phases.