Schiff base-reduced chitosan aerogels with enhanced iodine capture: 3D nano-porous networks for efficient iodine-contaminated water remediation.

Iodine, especially in the context of nuclear accidents, is considered one of the most hazardous pollutants. The efficient capture and recovery of iodine are crucial for managing accident wastewater and medical wastewater in nuclear power plants. Despite advancements, some materials developed for iodine removal still exhibit disadvantages such as complex synthesis processes, low removal capacity, and powder form, which limit their practical application. To address these challenges, chitosan aerogels with a three-dimensional nano-porous network structure were synthesized using glutaraldehyde crosslinking and vacuum freeze-drying techniques. The Schiff base structure formed during crosslinking was subsequently reduced, enhancing the adsorption capacity of the chitosan aerogel for iodine in solution from 1174.36 mg g-1 to 1419.25 mg g-1. Both the original and modified materials achieved an iodine removal rate of up to 98%. In dynamic adsorption experiments, both materials demonstrated excellent performance in removing iodine from saturated solutions. The adsorption mechanism involves interactions between iodine and nitrogen-containing functional groups within the aerogel matrix. Additionally, the swelling behavior of the aerogel significantly influences its adsorption capacity. These materials exhibit outstanding adsorption efficiency, excellent chemical stability, and reusability, making them promising, environmentally friendly, and efficient adsorbents for iodine removal from water.