Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, School of Physics and Electronics Science, East China Normal University, 500 Dongchuan Road, 201100 Shanghai, China E-mail:
Water Sci Technol. 2020 Feb;81(3):491-498. doi: 10.2166/wst.2020.124.
Constructing new cation exchange membranes (CEM) has been regarded as an easy and effective approach to improving the capacitive deionization (CDI) system. In this study, a new method of fabrication of CEM was introduced by crosslinking sulfosuccinic acid (SSA) and citric acid (CA). The SSA and CA were crosslinked with polyvinyl alcohol (PVA) to fabricate CEMs in a series of conditions. The ion transference number for each fabricated membrane was tested to select the optimal recipe. The membrane fabricated by the selected method was then tested in the CDI system and the results show that the total percentage of SSA could be reduced from 5% to 1% by adding 5 g of non-toxic and inexpensive CA. The cost of preparing the membrane also decreased from US$0.18 per square meter to US$0.03. The adsorption capacity and the charge efficiency of membrane capacitive deionization system (MCDI) coated with a PVA/SSA/CA layer (mass ratio 10:1:5) was compared with the normal CDI and the MCDI coated with the original membrane (PVA:SSA = 19:5), which is named O-MCDI). The results show that with the modified membrane, the adsorption capacity and the charge efficiency can be enhanced by 18% and 28% compared with the CDI. In addition, although the cost is reduced, the desalination efficiency is still guaranteed. The adsorption capacity and charge efficiency are still increased by about 3% compared with the O-MCDI.
构建新型阳离子交换膜（CEM）被认为是改善电容去离子（CDI）系统的一种简单而有效的方法。在这项研究中，通过交联磺基琥珀酸（SSA）和柠檬酸（CA）引入了一种制造 CEM 的新方法。SSA 和 CA 与聚乙烯醇（PVA）交联，在一系列条件下制备 CEM。测试了每个制备的膜的离子迁移数，以选择最佳配方。然后在 CDI 系统中测试了用选定方法制备的膜，结果表明，通过添加 5g 无毒且廉价的 CA，可以将总 SSA 含量从 5%降低至 1%。制备膜的成本也从每平方米 0.18 美元降低至 0.03 美元。与普通 CDI 和用原始膜（PVA：SSA = 19：5）涂覆的膜电容去离子系统（MCDI）相比，涂覆有 PVA/SSA/CA 层（质量比 10：1：5）的 MCDI 的吸附容量和电荷效率进行了比较（命名为 O-MCDI）。结果表明，与改性膜相比，CDI 的吸附容量和电荷效率可提高 18%和 28%。此外，尽管成本降低了，但仍能保证脱盐效率。与 O-MCDI 相比，吸附容量和电荷效率仍分别提高了约 3%。
