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Explication of Water Splitting Mechanism and Fundamental Research of Materials and Systems Designs in Bipolar Membranes

双极膜水分解机理的阐述以及材料和系统设计的基础研究

基本信息

批准号：
10450294
负责人：
TANIOKA Akihiko
金额：
$ 3.39万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

The bipolar membrane is a layered structure involving a cation selective membrane joined to an anion selective one. Water splitting has to be accompanied with water dissociation into hydrogen and hydroxide ions caused in the boundary surface between anion and cation layers and successive ion diffusion through charged layers. It is of practical interest in a new process for the commercial production of acid and base. As a result of the impedance measurements of the bipolar membranes under the constant d.c. biased voltages, it was observed that the electric conductivity and the electric capacity under reverse-biased voltage showed quite different behavior from all the other applied voltage and membrane conditions. The reduction in both the specific electric conductivity and the dielectric constant of the intermediate layer was implied by the impedance results that were analyzed using equivalent circuits.The current-voltage characteristics of bipolar membrane/LiCl + alcohol systems were measured and compared with those of the LiCl + water system. In this study, methanol, ethanol, 1-propanol, ethylene glycol and propylene glycol were examined and lithium chloride was employed as an electrolyte. The current-voltage curves suggested that the dissociation into the cation and the anion had occurred also in the methanol system in the interface between the anion exchange and cation exchange layers. The product in the anion exchange layer side was analyzed in the LiCl + methanol system to prove the generation of lithium methoxide. In addition, the difference in the current-voltage characteristics in the other LiCl + alcohol systems to be compared with the LiCl + methanol system and the effect of water as an impurity were discussed.

双极膜是包括阳离子选择性膜和阴离子选择性膜的层状结构。水的分解必须伴随着水在阴阳离子层之间的界面上解离成氢和氢氧化物离子，以及离子在带电层中的连续扩散。这对工业化生产酸碱的新工艺具有实际意义。通过对双极膜在恒定直流电场下的阻抗测量，得出了双极膜在恒定直流电场下的阻抗分布。在偏置电压下，观察到在反向偏置电压下的电导率和电容表现出与所有其他施加电压和膜条件下相当不同的行为。用等效电路分析的阻抗结果表明，中间层的比电导率和介电常数都有所降低。测量了双极膜/LiCl+乙醇体系的伏安特性，并与LiCl+水体系的伏安特性进行了比较。本研究以氯化锂为电解液，考察了甲醇、乙醇、正丙醇、乙二醇和丙二醇的溶液性质。电流-电压曲线表明，在阴离子交换层和阳离子交换层之间的界面上，甲醇体系也发生了阳离子和阴离子的解离。在LiCl+甲醇体系中对阴离子交换层侧的产物进行了分析，证明了甲醇锂的生成。此外，还讨论了其他LiCl+乙醇体系与LiCl+甲醇体系的伏安特性的差异，以及水作为杂质的影响。