Electrically regenerated ion-exchange technology: Leveraging faradaic reactions and assessing the effect of co-ion sorption

Journal Article · 22 May 2022 · Journal of Colloid and Interface Science

DOI: https://doi.org/10.1016/j.jcis.2022.05.104 · OSTI ID:1869286

Hackl, Lukas  ^[1]; Tsai, Shao-Wei  ^[2]; Kalyan, Bavisha  ^[1]; Hou, Chia-Hung  ^[2]; Gadgil, Ashok  ^[1]

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1. Univ. of California, Berkeley, CA (United States)
2. National Taiwan Univ., Taipei (Taiwan)

Capacitive deionization (CDI) technologies have the potential to become cost-competitive alternatives to reverse osmosis for the treatment of brackish waters. In this study, we describe our findings on the effect of co-ion sorption and faradaic side reactions on our ion exchange resin functionalized desalination electrodes which passively capture salt and reject it upon charging. This system, which we previously reported on and refer to as electrically regenerated ion exchange (ERI), avoids the use of expensive ion exchange membranes in an effort to save costs. Surprisingly, we find that, compared to a reference CDI system, ERI electrodes capture salt most effectively at low applied voltages (0.5 mg/cm³ at 0.8 V). Both CDI and ERI systems also seem to suffer from co-ion sorption effects which negatively impact salt adsorption. However, Faradaic side reactions at higher voltages (1 V and 1.2 V) which we track via pH measurements, serve as a detriment to CDI but seem to facilitate the functionality of ERI.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: U.S.-China Clean-Energy Research Center. Water Energy Technologies; USAID Global Development Lab and Higher Education Solutions Network; USDOE Office of Science (SC), Basic Energy Sciences (BES); the Ministry of Science and Technology, Taiwan
• Grant/Contract Number: AC02-05CH11231; IA0000018
• OSTI ID: 1869286
• Journal Information: Journal of Colloid and Interface Science, Journal Name: Journal of Colloid and Interface Science Vol. 623; ISSN 0021-9797
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English