Charged adsorbents for iodine capture

Radioactive iodine isotopes, such as 129 I and 131 I, present in nuclear waste are not only highly volatile but also tend to bioaccumulate in marine organisms, ultimately posing severe health risks to humans through the food chain. This critical challenge has spurred the development of advanced materials for the effective capture and safe storage of radioactive iodine. Charged adsorbents show great promise for iodine uptake through a range of noncovalent interactions including electrostatic forces, hydrogen bonding, anion-π interactions, and halogen bonding with iodine species, thereby improving adsorption performance. These charged materials demonstrate strong affinities for iodine species. This review summarizes the recent progress of various charged adsorbents, including metal-organic frameworks (MOFs), ionic liquids (ILs), porous aromatic frameworks (PAFs), porous organic polymers (POPs), covalent organic frameworks (COFs), macrocycles and molecular cages. Finally, the article discusses emerging trends and future prospects for charged adsorbents aimed at capturing radioactive iodine. • An in-depth analysis of a series of charged iodine adsorbents is provided. • Iodine capture mechanisms, performance metrics, and structure-property relationships are discussed. • Current limitations, emerging trends and future research directions are concluded.