β-FeOOH Nanospindles as Chloride-Capturing Electrodes for Electrochemical Faradic Deionization of Saline Water
Lu Zhang, Harry Lye Hin Chong, Pak Yan Moh, Munirah D. Albaqami, Ammar M. Tighezza, Chengjin Qin, Xinyi Ni, Jing Cao, Xingtao Xu, Yusuke Yamauchi
Abstract
Abstract Electrochemical faradic deionization (EDI), one of the most promising research branches of capacitive deionization (CDI), has demonstrated considerable potential for water desalination and ion removal (particularly at medium to low salinity). However, the associated relatively slow anion-capturing kinetics have limited the practical applications of EDI. Based on several studies, researchers have attributed this slow anion-capturing rate to the sluggish conversion-reaction-induced anion-capturing process (as most anion-capturing electrodes belong to the conversion type). Herein, we report a strategy for accelerating the anion-capturing process to enhance the desalination rate of EDI by utilizing an intercalation-type FeOOH electrode. The chloride-driven EDI system equipped with hollandite-type FeOOH nanospindles is found to present a high desalination rate (up to 4.44 mg g−1 min−1) and desalination capacity (51.77 mg g−1). The current study can inspire the future design of ultrafast EDI systems and bring the EDI technique closer to its practical application.