Ion Sieving in Two-Dimensional Membranes from First Principles
Abstract
A first-principles approach for calculating ion separation in solution through two-dimensional (2D) membranes is proposed and applied. Ionic energy profiles across the membrane are obtained first, where solvation effects are simulated explicitly with machine-learning molecular dynamics, electrostatic corrections are applied to remove finite-size capacitive effects, and a mean-field treatment of the charging of the electrochemical double layer is used. Entropic contributions are assessed analytically and validated against thermodynamic integration. Ionic separations are then inferred through a microkinetic model of the filtration process, accounting for steady-state charge separation effects across the membrane. The approach is applied to Li, Na, K sieving through a crown-ether functionalized graphene membrane, with a case study of the mechanisms for a highly selective and efficient extraction of lithium from aqueous solutions.
Cite
@article{arxiv.2412.13899,
title = {Ion Sieving in Two-Dimensional Membranes from First Principles},
author = {Nicéphore Bonnet and Nicola Marzari},
journal= {arXiv preprint arXiv:2412.13899},
year = {2024}
}