多层结构双极膜的传质及催化水解离机理

A bipolar membrane (BM) is a laminar functional composition of membrane that at least consists of a layer ion-exchange structure composed of a cation selective membrane (with negative fixed charges) and an anion selective membrane (with positive fixed charges). Electrodialysis with a bipolar membrane (EDBM) technology, which is regarded as the one of most promising fields, has acted as a new growth point in membrane industries due to its large and important potential applications in cleaning production and environmental protection. The main popurse of this project is to propose new mechanisms for water dissociation and catalytic water dissociation in a multi-layer bipolar membrane(BPM), respectively, based on the classic physical equations and masstransfer-reaction theories. Particular attentions have been given to the transport of the water ions and electrolyte ions as well as the membrane physical structure and configurations. Specifically speaking, we have attained following results through this project..1). We proposed a new concept-asymetry for bipolar membrane processes, and found the optiminium matching state of anion and cation layers into a BPM. 2).Catalytic water dissociation was focused in this project and a guidline for choosing a catlyst is initiated and different views are proposed for different catalysts shch as such as amphiprotic macromolecules and hydrophilic macromoles,etc. Our results showed that hyrophilic macromolules such as PEG possessed catalytic effect in a middle layer of BPM due to hydrogen-bonding and polar interactions between PEG and water and amphiprotic macromolecules such as BSA has a hindrance effect which is conflict with most literatures that this kind of materials has catalytic effect. Our explanation for this is that the conformational changes of BSA and an increase in the hydrophobicity give rise to an increase in voltage across a BPM. 3).We iniated a new route for preparing anion exchange layer of a BPM without using chloromethyl methyl ether, which is a carcinogen and is potentially harmful to human health.4).Application of BPM in the production of citric acid by water dissociation was also considered and the resultan product concentration can attain as high as 30 g/l. The above results can provide a solid basis for the preparation and applications of such bipolar membrane.

运用经典物理学方程和传质反应有关理论，研究双极膜的传质和催化水解离机理，建立多层结构水解离双极膜理论工作压降与其影响因素的定量关系模型，探讨强化双极膜水解离的有效措施，制出小膜样，测定其工作性能曲线，对所提出的理论模型进行验证。本文的研究成果为双极膜的制备及其相关应用提供坚实的理论基础。