Zn, O Co-adsorption based on MOF-5 for efficient capture of radioactive iodine

Abstract

The harmful effects of iodine in nuclear waste gas on humans and the environment, as well as the high kinetic energy of iodine molecules caused by the high-temperature environment, make it very important to develop and produce adsorbents with many active sites. The performance and mechanism of iodine capture by MOF-5 were investigated by experiments and molecular simulations for environmental protection. It was found that the synthesized MOF-5 can remove iodine from the gas phase and cyclohexane solution, with a high iodine capture capacity (0.63 g g-1) at 75 ℃. The cycling test illustrated the better recoverability and stability of MOF-5. The iodine capture capacity of MOF-5 in the liquid phase was 155 mg g-1, which is not the same as that of iodine in the gas phase. The multi-scale mechanistic analysis revealed that the adsorption process of MOF-5 on iodine was dominated by chemisorption, and the efficient capture of iodine was achieved by the co-adsorption of the central metal Zn atom and the tetrahedral apex O atom of MOF-5. This study provides insight into the iodine trapping process and adsorption mechanism, which is instructive for environmental protection engineering.