(544a) Mechanistic Understanding of Selective Interaction of Divalent Ions with Titanosilicate ETS-10

Unlike conventional zeolites, the Engelhard Titanosilicate material ETS-10 consists of both tetrahedral and octahedral building units. The presence of octahedrally coordinated titanium generates a high charge density in the framework thus a large number of exchangeable charge balancing cations. Combining this unique characteristic and the three dimensionally connected wide pores, ETS-10 is regarded as a promising material for adsorption, ion exchange and catalysis. Experimentally, high affinity of ETS-10 towards divalent ions is observed in ion exchange studies. The main focus of this study is to investigate the interaction of divalent ions using atomic and quantum scale simulations. Mechanistic insight was provided into the sorption mechanisms of heavy metal ions Pb²⁺, Cd²⁺ and Cu²⁺ in Na-ETS-10. The residence time distributions, mean-squared displacements, and radial distribution functions were determined to characterize sorption dynamics. The exchange capability of Na-ETS-10 for the three heavy metal ions follows the order of Pb²⁺ > Cd²⁺ > Cu²⁺, consistent with experimental observations.