Document Type
Article
Abstract
We employ density functional theory calculations to investigate the energetics and diffusion mechanisms of alkali metal ions (Na+, K+, Rb+, and Cs+) within the analcime framework. While Na+preferentially adsorbs at the center of the 8-member ring, DFT calculations show that larger ions, such as Cs+, occupy the center of the cage due to steric constraints. The computed exchange energies indicate that exchange of Na+by Cs+is thermodynamically favorable. Migration energy barriers, determined using the climbing image nudged elastic band method, show that Na+is mobile in analcime, diffusing through both 6-member rings and 8-member rings, with a low migration energy of about 0.3 eV; Cs+diffusion primarily occurs through the 8-member ring pathway, with a high energy barrier of 1.35 eV, whereas the 6-member ring pathway presents even significantly higher barriers (∼3.37 eV), making it less accessible. These findings suggest that Cs+/Na+exchange in analcime is thermodynamically feasible but kinetically hindered. Our work provides a theoretical foundation for the application of analcime in nuclear waste management and highlights the need for further experimental validation.
Digital Object Identifier (DOI)
Publication Info
Published in Physical Chemistry Chemical Physics, Volume 27, 2025, pages 25512-25523.
Rights
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.
APA Citation
Liu, J., Ta, A. T., Ullberg, R. S., Hounfodji, J. W., Badawi, M., zur Loye, H.-C., & Phillpot, S. R. (2025). Energetics and kinetics of alkali ion exchange in analcime. Physical Chemistry Chemical Physics, 27, 25512–25523.https://doi.org/10.1039/d5cp02373d