Ion Transport and Selectivity in sub-nm Nanopores—Insights from Integrated Multiscale Simulations

The ability to precisely control the ion transport and selectivity in sub-nm nanopores would have a transformative impact on a wide range of emerging technologies, from gas separation to water treatment and energy storage. In this talk, we will discuss how multiscale simulations are applied to elucidate the mechanism of ion transport and selectivity in both 1D and 2D nanopores. We will show how first-principles simulations is combined with force-field based approaches to predict ion solvation and transport in narrow carbon nanotubes (CNTs). Ion transport is found to be suppressed under confinement, which is associated with the transition in the Fickian diffusion to a single-file mechanism as the CNT diameter decreases. In addition, we show that ion-pore interactions can significantly influence the transport properties, leading to a strong correlation between ion dehydration, ion pairing, and diffusion. Finally, we will discuss how first-principles simulations can be coupled with implicit solvation models to investigate ion selectivity in 1D and 2D systems. Overall, these simulations highlight a complex interplay between nanopore geometry, ion shape and hydration on the selectivity.<br/>This work was performed under the auspices of the U.S. Department of Energy under Contract DE-AC52-07NA27344. This work was supported as part of the Center for Enhanced Nanofluidic Transport (CENT), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award No. DE-SC0019112.