Department of Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708, WG, Wageningen, The Netherlands.
Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, The Netherlands.
Adv Mater. 2019 Mar;31(10):e1806937. doi: 10.1002/adma.201806937. Epub 2019 Jan 9.
Capacitive deionization (CDI) typically uses one porous carbon electrode that is cation adsorbing and one that is anion adsorbing. In 2016, Smith and Dmello proposed an innovative CDI cell design based on two cation-selective electrodes and a single anion-selective membrane, and thereafter this design was experimentally validated by various authors. In this design, anions pass through the membrane once, and desalinated water is continuously produced. In the present work, this idea is extended, and it is experimentally shown that also a choice for anion-selective electrodes, in combination with a cation-selective membrane, leads to a functional cell design that continuously desalinates water. Anion-selective electrodes are obtained by chemical modification of the carbon electrode with (3-aminopropyl)triethoxysilane. After chemical modification, the activated carbon electrode shows a substantial reduction of the total pore volume and Brunauer-Emmett-Teller (BET) surface area, but nevertheless maintains excellent CDI performance, which is for the first time that a low-porosity carbon electrode is demonstrated as a promising material for CDI.
电容去离子（CDI）通常使用一个多孔碳电极，该电极具有阳离子吸附性，另一个电极具有阴离子吸附性。2016 年，Smith 和 Dmello 提出了一种基于两个阳离子选择性电极和一个阴离子选择性膜的创新 CDI 电池设计，此后，许多作者对该设计进行了实验验证。在该设计中，阴离子只需穿过膜一次，即可连续生产脱盐水。在本工作中，扩展了这一想法，并通过实验表明，选择阴离子选择性电极，并与阳离子选择性膜结合，也可以得到具有连续脱盐功能的电池设计。阴离子选择性电极是通过（3-氨丙基）三乙氧基硅烷对碳电极进行化学修饰得到的。化学修饰后，活性炭电极的总孔体积和 Brunauer-Emmett-Teller（BET）表面积显著减少，但仍保持出色的 CDI 性能，这是首次证明低孔隙率碳电极是 CDI 的有前途的材料。
