Carbazole–Bismaleimide Based Hyper-Cross-Linked Porous Organic Polymer for Efficient Iodine Capture

Radioactive iodine, a key waste product of nuclear energy, has been a significant concern among nuclear materials because of its high volatility and its ability to easily enter the human metabolism. Porous materials containing a large number of N-heterocyclic units such as carbazole in the skeletons use as effective adsorbents showing high iodine capture capacities. Herein, a new carbazole-bismaleimide-based hyper-cross-linked porous organic polymer (CzBMI-POP) was successfully prepared from a new tetra-armed carbazole-maleimide monomer (Bis-Cz(BMI)), which contains biscarbazole units and maleimide side groups. To produce CzBMI-POP, a free radical polymerization reaction was carried out via the unsaturated double bonds of Bis-Cz(BMI), enabling the construction of the N-rich porous skeleton in a simple and practical way. A high surface area carbazole-bismaleimide-based POP with polymer backbone having affinity for iodine uptake and sponge-like pore structures ranging from 2 to 20 nm showed iodine uptake capacity up to 215 wt %. The study highlights new opportunities to use POPs as iodine capture platform from nuclear waste, highlighting their potential for environmental remediation due to their easy synthesis and low cost.