物理化学学报 >> 2022, Vol. 38 >> Issue (5): 2006037.doi: 10.3866/PKU.WHXB202006037

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电容去离子除氯电极的构建及其脱盐性能研究进展

熊岳城1, 于飞2, 马杰1,3,*()   

  1. 1 同济大学长江水环境教育部重点实验室,上海 200092
    2 上海海洋大学海洋生态与环境学院,上海 201306
    3 上海污染控制与生态安全研究院,上海 200092
  • 收稿日期:2020-06-12 录用日期:2020-07-07 发布日期:2020-07-13
  • 通讯作者: 马杰 E-mail:jma@tongji.edu.cn
  • 作者简介:马杰,教授,博士生导师,2009年博士毕业于上海交通大学,长期从事环境修复材料及电容去离子电极材料的设计和开发,主持国家自然科学基金3项及多项省部级课题的实施
  • 基金资助:
    国家自然科学基金(21777118)

Research Progress in Chlorine Ion Removal Electrodes for Desalination by Capacitive Deionization

Yuecheng Xiong1, Fei Yu2, Jie Ma1,3,*()   

  1. 1 Key Laboratory of Yangtze River Water Environment, Tongji University, Shanghai 200092, China
    2 College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
    3 Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
  • Received:2020-06-12 Accepted:2020-07-07 Published:2020-07-13
  • Contact: Jie Ma E-mail:jma@tongji.edu.cn
  • About author:Jie Ma, Email: jma@tongji.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21777118)

摘要:

电容去离子技术(Capacitive deionization,CDI)是一种新兴的脱盐技术,通过在电极两端施加较低的外加电场除去水中的带电离子和分子,由于其较低的能耗和可持续性而备受关注。基于储能电池领域近年来的迅猛发展,CDI电极材料实现了从以双电层作用机理为代表的碳材料到法拉第电极材料的跨越,使得脱盐性能有了大幅度提升。Na+的去除与Cl-的去除同等重要,然而,CDI中针对氯离子高效去除的电极材料研究关注较少。本文从CDI装置的构型演变发展出发,系统地归纳与梳理了CDI中关于脱氯电极材料的分类,对比了不同类型脱氯电极材料的特点,并总结了Cl-去除的机理,分别为基于双电层的电吸附、转化反应、离子插层和氧化还原反应。本文是首篇关于CDI阳极材料的进展综述和展望,为CDI除氯电极的后续研究提供理论基础和研究思路。

关键词: 电容去离子, 脱盐, 阳极, 氯离子, 电池

Abstract:

Sustainable freshwater supply is a grave challenge to the society because of the severe water scarcity and global pollution. Seawater is an inexhaustible source of industrial and potable water. The relevant desalination technologies with a high market share include reverse osmosis and thermal distillation, which are energy-intensive. Capacitive deionization (CDI) is a desalination technology that is gaining extensive attention because of its low energy consumption and low chemical intensity. In CDI, charged species are removed from the aqueous environment via applying a voltage onto the anode and cathode. For desalination, Na+ and Cl- ions are removed by the cathode and anode, respectively. With the boom in electrode materials for rechargeable batteries, the Na+ removal electrode (cathode) has evolved from a carbon-based electrode to a faradaic electrode, and the desalination performance of CDI has also been significantly enhanced. A conventional carbon-based electrode captures ions in the electrical double layer (EDL) and suffers from low charge efficiency, thus being unsuitable for use in water with high salinity. On the other hand, a faradaic electrode stores Na+ ions through a reversible redox process or intercalation, leading to high desalination capacity.However, the Cl- removal electrode (anode) has not yet seen notable development. Most research groups employ activated carbon to remove Cl-, and therefore, summarizing Cl- storage electrodes for CDI is necessary to guide the design of electrode systems with better desalination performance. First, this review outlines the evolution of CDI configuration based on the electrode materials, suggesting that the anode and cathode are of equal importance in CDI. Second, a systematic summary of the anode materials used in CDI and a comparison of the characteristics of different electrodes, including those based on Ag/AgCl, Bi/BiOCl, 2-dimensional (2D) materials (layered double hydroxide (LDH) and MXene), redox polymers, and electrolytes, are presented. Then, the underlying mechanism for Cl- storage is refined. Similar to the case of Na+ storage, traditional carbon electrodes store Cl- via electrosorption based on the EDL. Ag/AgCl and Bi/BiOCl remove Cl- through a conversion reaction, i.e., phase transformation during the reaction with Cl-. 2D materials store Cl- in the space between adjacent layers, a process referred as ion intercalation, with layered double hydroxide (LDH) and MXene showing higher Cl- storage potential. Redox polymers and electrolytes allow for Cl- storage via redox reactions. Among all the materials mentioned above, Bi/BiOCl and LDH are the most promising for the construction of CDI anodes because of their high capacity and low cost. Finally, to spur the development of novel anodes for CDI, the electrodes applied in a chlorine ion battery are introduced. This is the first paper to comb through reports on the development of anode materials for CDI, thus laying the theoretical foundation for future materials design.

Key words: Capacitive deionization, Desalination, Anode, Chlorine ion, Battery

MSC2000: 

  • O646