Constructing imidazole-based ionic hyper-cross-linked polymers with tunable nanostructures and their application in radioactive iodine removal

Radioactive iodine isotopes with various types and valence states pose a significant hazard to human health and environmental safety. Consequently, the development of an effective adsorbent that can simultaneously remove different types of iodine is of significant importance. In this study, a series of iHCPs (iHCP[Im a P b ] c ) with tunable nanostructures were synthesized using a highly distorted monomer (V 3 N 6 -IL) and pyrrole as structural units via the Friedel-Crafts reaction. The tunable nanostructures were achieved by controlling the reaction components, leading to the appearance of structures including nanobars, nanostrips, nanofibers, nanosheets, and nanodarts. It was noteworthy that the characteristics of the building units endowed iHCP[Im a P b ] c with three distinct functional adsorption sites, namely heteroatoms, aromatic rings and ionic groups, which enabled iHCP[Im a P b ] c for the purpose of adsorbing iodine (I 2 )/iodide (I – ). The maximum adsorption capacity of iHCP[Im 0.2 P 1 ] 20 for I – was 418.41 mg g −1 , surpassing most reported polymeric adsorbents. Furthermore, iHCP[Im 0.2 P 1 ] 20 also had excellent I 2 adsorption capacity in cyclohexane up to 510.70 mg g −1 . Concurrently, iHCP[Im 0.2 P 1 ] 20 exhibited favorable recyclability in the I 2 and I – adsorption cycle experiment. In conclusion, the present study demonstrates a promising adsorbent material for the removal of I 2 /I – .