Iodine capture by ZSM-5 with different Si/Al ratios: An experimental and molecular simulation investigation

Abstract

In order to capture radioactive iodine from nuclear power waste gas, the performance and mechanism of iodine capture by ZSM-5 molecular sieves were analyzed in this paper by experiments and molecular simulations. The results of the experiment showed that the iodine adsorption capacity increased with the increasing Si/Al ratio of the ZSM-5, and rose and then fell with increasing temperature. After four adsorption-desorption cycles, it could still maintain good morphology and adsorption performance (83.17%–90.61%). The molecular simulation results found that as the Si/Al ratio increased, the average bond length of the I–I bond increased, the adsorption energy increased, the interaction between iodine and molecular sieve increased, and the adsorption capacity of iodine increased, which was consistent with the experimental results. In this study, the capture process and adsorption mechanism of iodine were further understood, and it provides a favorable scheme for the treatment of nuclear waste gas.