Next-generation brackish water treatment: Exploring dual-ion capacitive deionization

Abstract

The escalating global freshwater crisis presents a formidable challenge to development, with desalination emerging as a prominent solution. Among the diverse array of desalination technologies, capacitive deionization (CDI) holds significant promise, surpassing conventional methods such as reverse osmosis and distillation. However, the inherent limitations in the physical adsorption capacity of carbon electrodes have, thus far, impeded CDI’s desalination capacity from reaching its full potential. The burgeoning field of dual-ion capacitive deionization (DICD) has garnered significant attention. Upon application of an electric current, electrode materials in DICD configurations engage in Faradaic reactions with both cations and anion thereby demonstrating enhanced desalination efficiency and an expanded scope of potential applications. The performance of DICD is inextricably linked to the meticulous selection and design of electrode materials, prompting researchers to pursue the development of diverse and highly efficient capture electrode materials specifically tailored for different ions. This review furnishes a comprehensive examination of CDI principles and performance indicators, analyzing the evolution of device configurations with a focus on channel design variations. Furthermore, the current landscape of electrode material in DICD configurations is explored, encompassing its application prospects and challenges within the realm of brackish water desalination. Future research endeavors will prioritize enhancing electrode material stability, mitigating costs, and pioneering the discovery of more efficient electrode materials to facilitate the commercial realization of DICD technology.