Hydroxyl and pyrrole functionalized polymeric frameworks for efficient aqueous and gaseous iodine sequestration

• Pyrrole functionalized polymers, POF15, POF16, and POF17, were developed from inexpensive monomers for aqueous, non-aqueous, and gaseous iodine scavenging. • All three polymers exhibited moderate to high gas-phase, aqueous-phase, and non-aqueous-phase iodine uptake. • The polymers could be easily regenerated and recycled without compromising the iodine uptake. Radioactive iodine, including I 129 and I 131 , poses significant environmental and health risks due to its high volatility, long half-life, and water solubility, making the effective capture and storage of these substances crucial for environmental remediation and nuclear waste management. In this context, adsorption-based capture of radioiodine by porous solids has gained considerable attention. Here, we present three chemically robust pyrrole-based porous organic polymers, IISERP-POF15, IISERP-POF16, and IISERP-POF17, for efficient gaseous and solution-phase (aqueous and non-aqueous) iodine sequestration. IISERP-POF17 exhibits a high iodine uptake of 3.07 g/g in the gas phase at 70 °C, as well as effective performance in a non-aqueous medium (hexane), with an uptake of 0.47 g/g at room temperature. In aqueous solution, IISERP-POF15 shows the highest iodine uptake, reaching 2.20 g/g at room temperature. These polymers hold high chemical stability and can be readily recycled with intact iodine capacity. X-ray photoelectron spectroscopy (XPS) analysis evidenced the occurrence of I 2 and polyiodides (I 3 – /I 5 – ) in the post iodine-adsorbed polymers. Infrared spectroscopic investigation of the polymers upon iodine adsorption indicated a strong interaction of I 2 with -OH and pyrrolic NH of the framework. The observed I 2 -framework interactions were further backed by molecular simulation using Density Functional Theory (DFT) calculations.