https://scholars.lib.ntu.edu.tw/handle/123456789/633001
標題: | Cation selectivity of activated carbon and nickel hexacyanoferrate electrode materials in capacitive deionization: A comparison study | 作者: | Chen, Tsai Hsuan Cuong, Dinh Viet Jang, Yunjai Khu, Ngee Zhen Chung, Eunhyea CHIA-HUNG HOU |
關鍵字: | Capacitive deionization | Electrochemical separation process | Electrosorption selectivity | Intercalating material | Porous carbon | 公開日期: | 1-十一月-2022 | 出版社: | PERGAMON-ELSEVIER SCIENCE LTD | 卷: | 307 | 期: | Pt 1 | 來源出版物: | Chemosphere | 摘要: | In this study, the electrosorption selectivity of porous activated carbon (AC) and nickel hexacyanoferrate (NiHCF), which represent two working mechanisms of capacitive electrosorption and redox intercalation, was investigated to separate cations in capacitive deionization (CDI). The cyclic voltammetry diagrams of AC showed the rectangular shape of double-layer charging, while that of NiHCF showed separated peaks associated with redox reactions. The specific capacitance of NiHCF was 143.6 F/g in 1 M NaCl, which was almost two times higher than that of AC. Cation selectivity experiments were conducted in single-pass CDI for a multi-cation solution. The electrosorption preference of the AC cathode was determined by a counterbalance between the ionic charge and hydrated size, reflecting the selectivity coefficient of different cations over Na+ in the range of 0.86–2.63. For the NiHCF cathode, the cation selectivity was mainly dominated by the hydrated radius and redox activity. Notably, high selectivities of K+/Na+ ≈ 3.57, Na+/Ca2+ ≈ 9.97, and Na+/Mg2+ ≈ 18.92 were obtained. A significant improvement in the electrosorption capacity and monovalent ion selectivity can be achieved by utilizing the NiHCF electrode. The study demonstrates the fundamental aspects and promising opportunities of CDI in regard to ion selectivity. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/633001 | ISSN: | 00456535 | DOI: | 10.1016/j.chemosphere.2022.135613 |
顯示於: | 環境工程學研究所 |
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