Cesium Capture via Cationic Faujasite Zeolite

Due to its high aqueous mobility and a half-life of thirty years, Cs¹³⁷ is a primary target for ionic capture during long-term storage of used nuclear fuel. Zeolitic faujasite materials have been demonstrated to be promising candidates for the industrial application of Cs⁺ capture because of their low cost and relatively high stability under radioactive conditions. However, while faujasites have the capability of possessing various cationic species, their relative Cs⁺ ionic exchange performances are yet to be fully established. Here, plane-wave density functional theory calculations are used to thermodynamically survey Cs⁺ exchange with several monovalent cations and assess differences between cationic and acidic faujasite zeolites. The effects of differing alkaline metals and selected transition metals on cationic exchange will be discussed while favorable adsorption sites in HY-2.5 faujasite will also be identified. This work was supported by the Center for Hierarchical Waste Form Materials (CHWM), an Energy Frontier Research Center (EFRC) funded by the United States Department of Energy Office of Basic Energy Sciences through Award DESC0016574.