Scalable and Continuous Water Deionization by Shock Electrodialysis

Abstract

Rising global demand for potable water is driving innovation in water treatment methods. Shock electrodialysis is a recently proposed technique that exploits deionization shock waves in porous media to purify water. In this letter, we present the first continuous and scalable shock electrodialysis system and demonstrate the separation of sodium, chloride, and other ions from a feed stream. Our prototype continuously removes over 99% (and up to 99.99%) of salt from diverse electrolytes over a range of concentrations (1, 10, and 100 mM). The desalination data collapse with dimensionless current, scaled to charge advection in the feed stream. Enhanced water recovery with increasing current (up to 79%) is a fortuitous discovery, which we attribute to electro-osmotic pumping. These results suggest the feasibility of using shock electrodialysis for practical water purification applications.