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Lab. on Chemical Redox Acceleration Technologies for Water Quality



Journal
Four-step constant voltage operation of hybrid capacitive deionization with composite electrodes for bifunctional deionization and lithium recovery | |
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Year of publication | 2023 |
Title of paper | Four-step constant voltage operation of hybrid capacitive deionization with composite electrodes for bifunctional deionization and lithium recovery |
Author | Sungho Bae, Sung-il Jeon, Woonghee Lee, Yerin Kim, Kangwoo Cho* |
Publication in journal | Desalination |
Status of publication | accepted |
Vol | 565 |
Link | https://doi.org/10.1016/j.desal.2023.116883 365회 연결 |
Efficient recovery of valuable resources from wastewater has emerged as a critical challenge in the era of carbon neutral society. Capacitive deionization (CDI) has been employed in electrochemical lithium recovery (ELR) processes based on selective Li+ intercalation to LiMn2O4 (LMO). We herein propose a four-step constant voltage operation (forward/zero/reverse/zero) of bifunctional hybrid CDI to produce deionized water as well as Li+-rich concentrate within a cycle. Especially, selective Li+ enrichment was possible without influent replacement since adsorption of competing ions and liberation of Li+ could occur simultaneously. This unique performance was enabled by composite electrodes on capacitive activated carbon cloth (ACC) impregnated with redox-active materials; LMO@ACC and Ag@ACC. Together with material characterization and electroanalysis on the composite electrodes, deionization (step 1; forward voltage) and Li+ enrichment (step 3; reverse voltage) by assembled LMO@ACC//Ag@ACC cell were evaluated by single pass experiments with binary NaCl and LiCl solution (10 mM each). Besides, a multi-stage operation with internal recycle confirmed long-term stability and continuous increase of Li purity for practical implementation. The advanced bifunctional CDI (ELR coupled with water treatment) paved a way to advance the resource recycle from wastewater. |