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

双极膜是一种层状结构，包括一个阳离子选择性膜连接到一个阴离子选择性膜。水裂解必须伴随着在阴离子和阳离子层之间的边界表面中引起的水解离成氢和氢氧根离子以及通过带电层的连续离子扩散。这是一种具有实际意义的工业化生产酸和碱的新方法。作为双极膜在恒定直流偏置电压下的阻抗测量的结果，观察到在反向偏置电压下的电导率和电容量显示出与所有其他施加电压和膜条件完全不同的行为。用等效电路分析了双极膜的阻抗结果，发现中间层的电导率和介电常数均有所降低，测量了双极膜/LiCl +乙醇体系的电流-电压特性，并与LiCl +水体系的电流-电压特性进行了比较。在这项研究中，甲醇，乙醇，1-丙醇，乙二醇和丙二醇进行了检查和氯化锂作为电解质。电流-电压曲线表明，在甲醇体系中，阴离子交换层和阳离子交换层之间的界面处也发生了解离成阳离子和阴离子。在LiCl +甲醇体系中分析阴离子交换层侧的产物以证明甲醇锂的生成。此外，还讨论了其它LiCl +醇体系与LiCl +甲醇体系电流-电压特性的差异以及杂质水的影响。

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.