SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2025, Vol. 85 ›› Issue (9): 228-237.DOI: 10.1016/j.cjche.2025.04.004

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Enhanced fluid-flow-field and electric-field synergistic interaction mechanism for lithium-ion separation in dilute solutions: A numerical analysis of electrochemically switched ion exchange system

Kangjun Ji1, Jingxuan Yang1, Xuefeng Zhang1, Mengbo Zhao1, Xiao Du1, Xiaogang Hao1, Abuliti Abudula2, Guoqing Guan2,3   

  1. 1. College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
    2. Faculty of Science and Engineering, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan;
    3. Section of Renewable Energy, Institute of Regional Innovation (IRI), Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan
  • Received:2025-02-27 Revised:2025-03-30 Accepted:2025-04-01 Online:2025-04-24 Published:2025-09-28
  • Contact: Jingxuan Yang,E-mail:yangjingxuan@tyut.edu.cn;Xiaogang Hao,E-mail:xghao@tyut.edu.cn
  • Supported by:
    This work is supported by the National Natural Science Foundation of China (22378285, 92475117 and U21A20303).

Enhanced fluid-flow-field and electric-field synergistic interaction mechanism for lithium-ion separation in dilute solutions: A numerical analysis of electrochemically switched ion exchange system

Kangjun Ji1, Jingxuan Yang1, Xuefeng Zhang1, Mengbo Zhao1, Xiao Du1, Xiaogang Hao1, Abuliti Abudula2, Guoqing Guan2,3   

  1. 1. College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
    2. Faculty of Science and Engineering, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan;
    3. Section of Renewable Energy, Institute of Regional Innovation (IRI), Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan
  • 通讯作者: Jingxuan Yang,E-mail:yangjingxuan@tyut.edu.cn;Xiaogang Hao,E-mail:xghao@tyut.edu.cn
  • 基金资助:
    This work is supported by the National Natural Science Foundation of China (22378285, 92475117 and U21A20303).

Abstract: Electrochemically switched ion exchange (ESIX) is an effective technology for extracting high-value-added ions from dilute solutions. This study focuses on Li+ extraction by employing a comprehensive model to analyze interaction between fluidic dynamics, electric field and ion transport. The model combines Butler-Volmer equation modified by electroactive site concentration, Nernst-Planck equation and Navier-Stokes equation. It is found that the chamber width affects solution phase resistance, thereby altering the potential distribution and influencing the current distribution within the membrane. A narrow chamber increases current density in the solid phase of the membrane, enhancing Li+ extraction. The solution flow-field not only enhances convective transport but also increases the current density in the solid phase, promoting Li+ extraction. There is a synergistic effect between fluid-flow-field and electric-field for ion separation, which is only significant when the chamber width is greater than 2 mm. The synergistic mechanism differs from that in the capacitive deionization system. Therefore, the performance decline caused by a wide chamber can be compensated for by increasing the fluid-flow rate, utilizing the synergistic effect between the fluid-flow-field and electric-field to optimize the lithium extraction efficiency in the ESIX system.

Key words: Electrochemically switched ion exchange, Mass transfer and separation, Synergistic effect, Fluid-flow-field, Fluidic dynamics, Electric-field

摘要: Electrochemically switched ion exchange (ESIX) is an effective technology for extracting high-value-added ions from dilute solutions. This study focuses on Li+ extraction by employing a comprehensive model to analyze interaction between fluidic dynamics, electric field and ion transport. The model combines Butler-Volmer equation modified by electroactive site concentration, Nernst-Planck equation and Navier-Stokes equation. It is found that the chamber width affects solution phase resistance, thereby altering the potential distribution and influencing the current distribution within the membrane. A narrow chamber increases current density in the solid phase of the membrane, enhancing Li+ extraction. The solution flow-field not only enhances convective transport but also increases the current density in the solid phase, promoting Li+ extraction. There is a synergistic effect between fluid-flow-field and electric-field for ion separation, which is only significant when the chamber width is greater than 2 mm. The synergistic mechanism differs from that in the capacitive deionization system. Therefore, the performance decline caused by a wide chamber can be compensated for by increasing the fluid-flow rate, utilizing the synergistic effect between the fluid-flow-field and electric-field to optimize the lithium extraction efficiency in the ESIX system.

关键词: Electrochemically switched ion exchange, Mass transfer and separation, Synergistic effect, Fluid-flow-field, Fluidic dynamics, Electric-field