Regenerable and stable calix[4]pyrrole-based porous organic polymer networks for highly effective iodine capture

Abstract

As a highly recalcitrant pollutant, the bioaccumulation of radioactive iodine severely endangers human health. Although many absorbents for iodine removal have been developed, the targeted design of adsorbents with high efficiency and reusability remains unexplored. Here, by crosslinking α,α,α,α-tetra(4-alkynylphenyl)calix[4]pyrrole (C4P) with co-monomers exhibiting different aryl units and electronic properties, a series of C4P-based porous organic polymers for iodine capture were designed and fabricated; the materials exhibit excellent adsorption performance for iodine in both gas and liquid phases. In particular, the polymer using 1,3,5-benzenetricarbaldehyde as a co-monomer (C4P-Tab) was found to have a rapid iodine adsorption rate and an uptake capacity of 3.96 g g⁻¹ for iodine aqueous solution at room temperature and atmospheric pressure. Flow-through adsorption experiments revealed that the breakthrough did not occur until 228 mL of the solution passed through the column for C4P-Tab at a flow rate of 0.40 mL min⁻¹. This study provides a reference for designing efficient and sustainable macrocyclic adsorbents for iodine capture.