Bi@PVP/PVA aerogels with 3D porous networks: High-performance trapping and immobilization of iodine vapor

• Bi@PVP/PVA aerogel was made by hydrothermal and freeze-drying methods. • It shows ultrahigh iodine uptake of 2482.2 mg/g, top among Bi-based adsorbents. • Uptake via chemisorption (forms BiI 3 ) and stable physisorption. • Offers new ideas for nuclear industry radioactive gas management. During the reprocessing of irradiated nuclear fuel, radioactive iodine vapor—a hazardous substance threatening environmental safety and human health—is released in substantial quantities, creating an urgent need for adsorbents with high-efficiency iodine trapping capabilities. This study synthesizes BiOBr aggregates via hydrothermal method and loads them onto a three-dimensional (3D) porous aerogel, which is composed of crosslinked polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) (denoted as Bi@PVP/PVA). Compared with Bi@PVP and Bi@PVA, Bi@PVP/PVA shows significantly enhanced iodine adsorption performance: Bi@PVP/PVA-3, featuring a well-developed 3D porous network with optimized pore structure, achieves an exceptional iodine trapping capacity of 2482.2 mg/g at 85 °C, outperforming the single-polymer-supported counterparts. Characterizations confirm that crosslinking between PVP and PVA constructs a macroporous framework, which not only provides abundant sites for uniform loading of BiOBr aggregates but also facilitates iodine diffusion. Kinetic model analysis reveals the dual adsorption mechanism: the PVP/PVA porous network enables rapid trapping of iodine vapor, while chemical reactions between BiOBr and iodine ensure its firm immobilization. This synergistic effect of the carrier’s porous structure and the loaded BiOBr endows Bi@PVP/PVA aerogels with superior iodine treatment efficiency, highlighting their practical value in iodine capture during nuclear fuel reprocessing.