Enhancing Iodine Capture of Porous Organic Cages through N-Heteroatom Engineering

Abstract

Iodine radioisotopes, produced or released during nuclear-related activities, severely affect human health and the environment. The efficient removal of radioiodine from both aqueous and vapor phases is crucial for the sustainable development of nuclear energy. In this study, we propose an "N-heteroatom engineering" strategy to design three porous organic cages with N-containing functional groups for efficient iodine capture. Among the molecular cages investigated, FT-Cage incorporating tertiary amine groups and RT-Cage with secondary amine groups show higher adsorption capacity and much faster iodine release compared to IT-Cage with imine groups. Detailed investigations demonstrate the superiority of amine groups, along with the influence of crystal structures and porosity, for iodine capture. These findings provide valuable insights for the design of porous organic cages with enhanced capabilities for capturing iodine.

Synthesis and Applications of Cage-Based Covalent Organic Frameworks

“…Efficiently capturing radioactive iodine is crucial for ensuring the safe and sustainable utilization of nuclear energy. Certain organic cages featuring nitrogen-rich functional groups have shown exceptional abilities for adsorbing iodine. − However, the densely packed structure of normal cages in their solid form hinders their ability to interact with iodine during the adsorption process. Additionally, their high solubility in aqueous solutions poses challenges for recycling.…”