Enhanced iodine capture through imidazole-modified 3D covalent organic frameworks

The efficient capture of radioactive iodine during the process of reprocessing nuclear fuel is crucial for ensuring nuclear safety and environmental preservation. In this study, a simple vaporization technique was employed to incorporate nitrogen-containing imidazole (Im) molecules into three-dimensional covalent organic frameworks (COFs), resulting in the successful synthesis of a series of highly efficient iodine adsorbents designated as Im@COFs. Compared to the pristine materials, Im@COFs demonstrated significantly enhanced adsorption performance, particularly with an iodine capacity that increased up to 1.9 times and a methyl iodide capacity that increased up to 70 %. The elevated nitrogen content not only augmented the number of binding sites but also intensified the interaction between the adsorbent and iodine molecules, thereby markedly enhancing the adsorption capacity. This method provides a novel and effective approach to improve the efficiency of iodine capture in nuclear fuel reprocessing.