Water Desalination: Electrostatic and Electrochemical Separation Processes

Abstract

Electrostatic and electrochemical separations offer significant potential in the deionization of water as either stand‐alone processes or pre‐/posttreatment processes for achieving targeted water quality. This article critically reviews these electrically driven methods for the desalination of water. We begin by chronicling the historical development of electrostatic and electrochemical separation processes in both research and commercial applications. Further, we review the fundamental transport and reaction phenomenon critical to process performance and define metrics for assessing this performance. The subsequent two sections provide a deeper review of CDI (electrostatic) and electrosorption (electrochemical ion removal), and electromembrane separation systems, such as electrodialysis (ED), electrodialysis reversal (EDR), and electrodeionization (EDI), as well as membrane‐assisted electrosorption systems. For each of these electrostatic or electrochemical separation methods, we discuss the process fundamentals, key challenges associated with these technologies as well as recent innovations in materials and process design that are overcoming historical limits. Finally, we conclude with a discussion of practical applications of these methods and summarize opportunities to advance electrochemical processes for materially and energy‐efficient ionic separations.