化工学报 ›› 2016, Vol. 67 ›› Issue (1): 309-314.DOI: 10.11949/j.issn.0438-1157.20151004

• 表面与界面工程 • 上一篇    下一篇

水-乙醇体系对双极膜中间界面层的影响

刘小菏, 李秋花, 葛亮, 徐铜文   

  1. 中国科学技术大学化学与材料科学学院, 安徽 合肥 230026
  • 收稿日期:2015-06-29 修回日期:2015-08-27 出版日期:2016-01-05 发布日期:2016-01-05
  • 通讯作者: 徐铜文
  • 基金资助:

    国家自然科学基金项目(21206155)。

Influence of aqua-ethanol medium on properties of intermediate layer ofa bipolar membrane

LIU Xiaohe, LI Qiuhua, GE Liang, XU Tongwen   

  1. School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, Anhui, China
  • Received:2015-06-29 Revised:2015-08-27 Online:2016-01-05 Published:2016-01-05
  • Supported by:

    supported by the National Natural Science Foundation of China (21206155).

摘要:

选取Neosepta BP-1,Fumasep FBM,CJ-BPM三种商业标准双极膜作为研究对象,以水-乙醇为研究体系,通过改变不同乙醇含量,测定双极膜的交流阻抗谱,并且对双极膜的耐溶剂性能进行评价,结果表明BP-1具有良好的耐溶剂性,FBM,CJ-BPM耐溶剂性相对较弱;水解离现象发生在LiCl水-乙醇混合溶液中,随着乙醇含量的增加,双极膜的阻值增加,而水解离程度降低。这种现象可以解释为醇解离能力要远远小于水解离能力,因此乙醇的存在使得中间界面层区域的水浓度降低,进而降低了水解离程度;通过简化算法计算出了不同乙醇含量下,BP-1,FBM的中间界面层厚度,更直观地看出乙醇对双极膜水解离性能的影响。

关键词: 水-乙醇体系, 膜, 离子交换, 电化学, 交流阻抗谱

Abstract:

A bipolar membrane (BPM) was composed of a cation and an anion ion-exchange layer joined together in series. The water dissociation in BPM was then considered as an electric field-enhanced (EFE) phenomenon and its magnitude depended critically on the structure and composition of the bipolar intermediate layer. By changing the different content of ethanol, three commercial bipolar membranes Neosepta BP-1, Fumasep FBM and CJ-BPM were tested by AC impedance spectra and their bipolar membrane solvent resistance were evaluated simultaneously. It was confirmed that BP-1 had good solvent resistance and FBM and CJ-BPM solvent resistances were relatively weak. The experimental results showed that the water dissociation phenomenon occurred in the LiCl water-ethanol mixed solutions, and the local effective value of the BPM resistance increased with an increase in the content of ethanol, while the water dissociation became less obvious. This phenomenon could be explained due to the fact that the dissociative ability of alcohol was weaker than that of water. Thus, the existence of ethanol decreased the concentration of water in the intermediate layer of a bipolar membrane and caused the decrease in the water dissociation effect. By simplifying the algorithm to calculate the intermediate layer thickness of the BP-1 and FBM membranes, it was more intuitive to know the influence of ethanol content on the water dissociation.

Key words: water-ethanol system, membrane, ion exchange, electrochemistry, AC impedance spectra

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