Functionalized chitosan-PEI composite hydrogels via dual crosslinking for enhanced iodine capture

The escalating global energy demand has intensified the reliance on nuclear power generation, necessitating advanced solutions for radioactive iodine sequestration from nuclear wastewater. Chitosan (CS) exhibits significant potential for radioactive iodine capture due to the ion-exchange capabilities of its amino and hydroxyl functional groups with iodide ions. Herein, a novel A/CS-PEI composite hydrogel was synthesized through crosslinking chitosan with acrolein and polyethyleneimine (PEI) for enhanced iodine adsorption. The effect of temperature, contact time, and initial concentration on the adsorption of iodine was studied. The results demonstrate that the adsorption capacity of the adsorbent for I 2 can achieve as high as 840.91 mg∙g −1 . Additionally, molecular dynamics simulations demonstrated that the maximum absolute adsorption energy of −214.50 kcal/mol was achieved at 318 K, an increase in temperature enhances the adsorption capacity to a certain extent. Also van der Waals interactions dominate the non-bonded energy components with a value of −197.99 kcal/mol. The adsorption mechanism can be explained by hydrogen bond, van der Waals force, electrostatic force and charge transfer interaction. This work establishes a fundamental framework for designing multifunctional hydrogels with tailored functionalities for nuclear waste remediation.