Phosphate-based, heteroatom-rich porous organic polymers for efficacious uptake of iodine in vapor phase

Abstract

Radioactive iodine pollution from nuclear waste poses significant threat to both the environment and human health. As a result, the utmost importance lies in the capture and safe storage of radioactive iodine. To address this concern, a set of porous organic polymers with phosphate linkages, namely AZO-POP-P, OPN-3, OPN-4, and OPN-5, were synthesized for the uptake of iodine in vapor phase. Additionally, a triazine-based porous organic polymer, AZO-POP-T was also synthesized to compare the iodine uptake capacity. Syntheses of these phosphate-linked and triazine-based polymers involved a nucleophilic substitution reaction of various aromatic alcohols with POCl3 or cyanuric chloride, respectively. This study represents an inaugural investigation into the iodine uptake capability by phosphate-based porous organic polymers. They exhibited efficient iodine capture from vapor phase, demonstrating uptake capacities of 3.56, 1.30, 2.70, and 0.63 g.g−1 for AZO-POP-P, OPN-3, OPN-4, and OPN-5 respectively, at 75 °C. Meanwhile, the triazine-based AZO-POP-T exhibited an uptake capacity of 1.83 g.g−1 at 75 °C. These porous organic polymers demonstrated easy and scalable synthesis, high thermal stability, and recyclability for at least five cycles without significant decrease in the uptake capacity towards volatile iodine from vapour phase.