A radiation-resistant supermacroporous aerogel for ultrafast and high-capacity gaseous iodine capture

Efficient capture of radioactive gaseous iodine is crucial for the safe management of nuclear waste. However, most existing adsorbents suffer from low capacity, slow kinetics, high cost, or poor radiation stability. Herein, a simple aqueous cryo-polymerization strategy was developed to construct a polyethyleneimine-functionalized poly (acrylic acid) aerogel (PEI@PAA), enabling simultaneous ice-templated macropore formation, in-situ polymerization, and crosslinking. The resulting aerogel features a highly interconnected three-dimensional (3D) macroporous network (10 ~ 100 μm), which facilitates the rapid diffusion of iodine vapor. Meanwhile, abundant amino groups (RNH₂, R₂NH, R₃N) act as chemical adsorption sites through charge-transfer interactions. The PEI@PAA aerogel exhibits an exceptionally high iodine uptake of 6.01 g·g^{− 1} and achieves 90% of its saturation capacity within 4 h, which demonstrates a 10-fold kinetic enhancement over that of Ag-loaded zeolites. Benefiting from the robust gel network and continuous pore structure, the aerogel exhibits a low linear shrinkage rate of ~ 11.1% after ambient temperature and pressure drying, far lower than that of conventional aerogels, maintains a high capacity of 5.14 ~ 5.28 g·g^{− 1} after exposure to 50 kGy of β/γ irradiation with negligible structural degradation, and also possesses excellent mechanical stability—its compressive strength is enhanced after irradiation due to radiation-induced additional crosslinking. This green and energy-efficient method eliminates the need for freeze-drying, offering a scalable and sustainable platform for the next generation of iodine adsorbents in nuclear waste treatment.