Molecular Dynamics Study on Absorption Characteristics of Anions (Br- and I-) in Type-A Zeolite in Molten LiCl-KCl Eutectic Salt

When a type-A zeolite is immersed in molten LiCl-KCl eutectic salt, the alkali and halogen elements in the salt phose are absorbed in the vacancies of the zeolite in the form of ions. Recently, it was revealed that r in molten LiCl-KCl-Kl salt exhibited; greater absorption in the zeolite than Cl, although Br- in molten LiCl-KCl-KBr Salt did not show such absorption behavior. In the present study, Molecular dynathics, caltulations, were performed to understand the difference in the absorption behavior of I- and, Br- in a type-A zeolite by caltulating the,dependences of the formation enthalpy of the zetilite containing several, alkali halides on the Composition of the halogen elements: From these calculations it appeared that the enthalpy is negative m a Cl-I mixture system, indicating that when a few I- ions are absorbed in a zeblite cage, More I- is absorbed than that expected from the I-/(I-+Cl-) ratio in the salt; i.e, I- is preferentially absorbed In contrast, no such negative potential appeared in the Cl-Br mixture syStem. Therefore, it was, qualitatively indicated that I- in molten LiCl-KCl salt is more preferentially absorbed in the type-A zeolite than Br- in the salt.