Porous organic polymers with spiro-thioketal linkages for effective iodine capture

Abstract

Radioactive iodine from nuclear waste poses a major threat to public safety due to its toxicity and long half-life. The capture and storage of radioactive iodine remains a major challenge. The incorporation of electron-rich heterocycles into the adsorbents could increase the adsorption capacity for iodine due to their strong interaction. In this study, three novel spiro-thioketal-based porous organic polymers, POPSP-1–3, were synthesized in excellent yields by a thiol-aldehyde polycondensation reaction. The polymers of POPSPs were thoroughly characterized using FT-IR, ¹³C-NMR, BET, and PXRD techniques. These analyses revealed that the polymers are amorphous in nature and have a low surface area. The iodine uptake capacities of POPSP-1, POPSP-2, and POPSP-3 were measured to be 4.13, 5.25, and 5.65 g g⁻¹, respectively, at a temperature of 75 °C due to the increased density of the adsorption sites. Furthermore, the POPSPs exhibit exceptional adsorption performance in iodine/n-hexane solution and their effectiveness in removing iodine is excellent. This work provides a novel approach for the development of sulfur-rich porous organic polymers (POPs) as effective adsorbents for iodine capture.