基于限域效应构建阻酸型阴离子交换膜及其在双极膜电渗析中的应用

Bipolar membrane electrodialysis (BPED) which sets the separation and synthesis as one will make conventional chemical production more integrated, green and high-efficiency. However, the proton leak through the anion exchange memranes (AEM) deterioates seriously the maximum concentration of products and the current efficiency of process. Thus, the AEM embracing a high performance in blocking acid migration is badly needed. In this project, a new method is proposed for solving the present dilemmas of the commercial acid-block AEM such as the rapid reduction of acid-block property and increasement of electric resistance after the intensive analyses on the relations between the structure and properties of the cation-exchange membranes used in Chlor-alkali industry and the commercial anion-exchange membranes. That is, a novel material embracing the hydrophobic backbones and positive side chains is synthesized for the achievement of a tailor-made membrane structure due to the phase separation. Accordingly, the formed ionic channels and the associated confinement effect will contribute to the endowment of acid-block property by facilitating the transport of anions, strengthenning the Donnon repulsion for protons, and improving the regulation for water molecules. Furthermore, series of characterization methods are developed for grasping the relations among the material, morphology and properties, expolring the proton leak mechanism, and understanding mass transfer within a restricted space. Thereupon, an universal model for BPED is constructed against the application background such as acid recovery and reclamation of salt-containing wastewater for the devise of electrodialyzer and the optimization of operation. Of course, the success of this project will pave the road for the development of the related membranes, such as bipolar membrane and ion exchange membrane used for fuel cell.

双极膜电渗析技术集分离与反应为一体，有望实现生产过程的集成化、绿色化和高效化。然而，过程中质子对阴膜的渗漏严重劣化了产品的最大浓度和过程的电流效率，迫切需求高效阻酸阴膜的研制。本项目瞄准当前阻酸阴膜电阻过高、阻酸性能衰减过快等重要问题，分析氯碱工艺用膜和当前商品阴膜的构效关系，提出：设计合成具有疏水主链与荷电亲水侧链的阻酸阴膜用膜材料，构建具有微观相分离的膜结构，利用藉此形成的离子通道及伴生的限域效应，促进膜对阴离子的传导，强化膜对质子的道南排斥，改善膜对水分子的管控，实现高效阻酸性能的赋予。进而，发展和完善离子膜的表征方法，把握膜材料、结构与性能的内在联系，探究阴膜的“酸泄漏”机理，深化对限域传质机制的认识。在此基础上，以酸回收和含盐废水资源化为应用背景，建立双极膜电渗析过程通用传质模型，为电渗析器设计和工艺操作优化等奠定理论基础。本项目的制膜策略也为双极膜和燃料电池隔膜的研发提供借鉴。

双极膜电渗析技术集分离与反应为一体，有望实现生产过程的集成化、绿色化和高效化。然而，过程中质子对阴膜的渗漏严重劣化了产品的最大浓度和过程的电流效率，迫切需求高效阻酸阴膜的研制。本项目瞄准当前阻酸阴膜电阻过高、阻酸性能衰减过快等重要问题，分析氯碱工艺用膜和当前商品阴膜的构效关系，提出：设计合成具有疏水主链与荷电亲水侧链的阻酸阴膜用膜材料，构建具有微观相分离的膜结构，利用藉此形成的离子通道及伴生的限域效应，促进膜对阴离子的传导，强化膜对质子的道南排斥，改善膜对水分子的管控，实现高效阻酸性能的赋予。进而，发展和完善离子膜的表征方法，把握膜材料、结构与性能的内在联系，探究阴膜的“酸泄漏”机理，深化对限域传质机制的认识。在此基础上，以酸回收和含盐废水资源化为应用背景，建立电渗析过程通用传质模型，为电渗析器设计和工艺操作优化等奠定理论基础。项目开展四年来，项目组紧紧围绕申请书所列研究目标精诚合作、不懈努力，在本领域公认的高水平期刊上发表SCI、EI论文十七篇，授权发明专利一件，出版书籍两部（各一章），培养研究生（含在读）二十余名，较满意地实现了申请书所预设的各相关指标。