Institution: | 1. Laboratory of Organic Chemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands;2. Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands;3. Soft Matter, Fluidics and Interfaces Group, Faculty of Science and Technology, University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands |
Abstract: | Ion-selective water treatment is needed to address emerging problems in an energy- and cost-efficient manner. Capacitive deionization (CDI) is a membraneless water treatment technology, which relies on storing ions in charged electric double layers (EDLs) of micropores. CDI has shown remarkable selectivity, with local density approximations (LDAs) showing some success in guiding selective separations. However, many underlying processes are represented by lumped fitting parameters in LDA models, hindering further progress. Atomistic models help unravel selectivity mechanisms, but are difficult to integrate with cell-level CDI theory. Here, we review and extend LDA models for CDI, highlight a knowledge gap in connecting between LDA and atomistic models for CDI, and emphasize and build upon analogies between micropore EDLs and nanofiltration membranes. |