Effects of different covalent organic frameworks structures on radioactive iodine adsorption

As low-carbon sustainable energy source, nuclear energy plays an increasingly important role in human progress. However, the operation of nuclear power plants has resulted in the emission of volatile radioactive pollutants, including iodine molecules (I-2) and methyl iodide (CH3I). Radioactive iodine ( 129,131 I) is harmful human health and should be removed from the exhaust gas. Covalent organic frameworks (COFs) are a emerging organic materials with tunable structures, unique inherent properties and excellent stability, have great potential as adsorbents for radioactive I-2 capture. This review summarized the common bonds, synthesis methods, and specifications of COFs as radioactive I-2 adsorbents. The effect of COF structures I-2 adsorption were discussed, and the relationships between the inherent characteristics of COF structures their adsorption performance were analyzed. In addition, the interaction mechanisms of COFs with radioactive were also discussed. We found that the tunable structures, pore sizes, flexibility, conjugated structure eroatoms of COFs have significant effect on the adsorption performance of I-2. Moreover, post-modification composites with other nanomaterials can improve the adsorption effectively. It is of great significance to COFs that can be used in practical radioiodine elimination. Finally, we also provide an overview of the challenges in practical applications.