Electroactive self-polymerized dopamine with improved desalination performance for flow- and fixed- electrodes capacitive deionization

• Published in: Applied surface science Vol. 579; p. 152154
• Main Authors: Tran, Nguyen Anh Thu, Phuoc, Ngo Minh, Khoi, Tran Minh, Jung, Hye Bin, Cho, Namchul, Lee, Young-Woo, Jung, Euiyeon, Kang, Beom-Goo, Park, Kyungtae, Hong, Jinkee, Yoo, Chung-Yul, Kang, Hong Suk, Cho, Younghyun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.03.2022
• Subjects: (Flow-Electrode) capacitive deionization; Desalination; Organic electrode; Polydopamine; Redox-active; Polydopamine; Redox-active; (Flow-Electrode) capacitive deionization; Desalination; Organic electrode
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2021.152154

[Display omitted] •Dopamine was polymerized onto the surface of activated carbon (PDA@AC).•PDA@AC electrodes provide higher hydrophilicity and suspension stability.•CDI and FCDI desalination performances using PDA@AC are significantly enhanced due to redox-active PDA functionality. Capacitive deionization (CDI) is an emerging desalination technology with several advantages, including a high energy efficiency and a simple process. In particular, flow electrode CDI (FCDI) shows greatly enhanced salt removal performance by supplying slurry electrodes into a cell, resulting in continuous desalination operation. Along with carbon-based electrodes, Faradaic materials have been widely introduced for FCDI desalination to realize a higher salt removal capacitance. Organic redox-active materials have received significant attention for replacing conventional inorganic electrodes due to their superior characteristics such as cost-effective and eco-friendly properties, light weight, and high theoretical capacity. In this study, dopamine was self-polymerized onto carbon surfaces to provide polydopamine (PDA) grown activated carbons (AC). Strong adhesion property of PDA prevented their dissolution in electrolytes during electrochemical reactions. In addition, it provided a much improved surface wettability and suspension stability. Results showed that the salt adsorption capacity of PDA@AC CDI electrode was significantly enhanced from 6.03 to 10.43 mg/g (a 73% increase). Salt removal rate of an FCDI was also greatly increased from 1.20 to 2.12 mmol/m2s (a 76% increase) for a PDA@AC slurry electrode. The demonstrated approach is expected to open a new door for realizing desalination of a highly saline solution including seawater.