容积泵送型智能电控重金属离子交换膜的制备与耦合传质机理

High energy consumption and heavy membrane contamination in the electrodialysis process and worse continuous operability in the electrically switched ion exchange process are limiting their large-scale application for the treatment of heavy metal wastewater. It is vital to develop an electrically switched ion exchange membrane system with higher recognition ability and faster potential response for the heavy metal ions when coupling it with the electrodialysis process for the wastewater treatment. In this proposal, novel co-polymer composites composed of aniline (or pyrrole) and pyridinedicarboxylic acid, in which variable valency metal complex is in situ embedded (PAPV), will be designed and synthesized. The heavy metal ion recognition ability and ion exchange capacity of the obtained PAPV will be improved by tuning the microstructure of probe-type ion-exchange functional unit based on the different binding forces acting between the objective heavy metal ion and organic ligands. Pumping effect for the ions diffused in the membrane is expected to be improved by modulating the content of variable valency metal complex in the PAPV membrane. Piston transfer effect of the proton in PAPV between conducting framework and the ion-exchange functional unit could be driven and controlled by regulating the redox states of the membrane. Thus, the objective heavy metal ions could be selectively captured and released by the aid of the transfer of proton. Furthermore, principle for the regulating of ion-exchange functional unit in the microstructure, kinetics for the growth of three dimensional PAPV membrane, mechanism for the transfer of interface charge (or ion), and coupling pumping effect of the membrane in the nano-submicro scale are also expected to be elucidated. All in all, our aim is to provide theoretical basis for the removing of heavy metal ion from wastewater using this developing technology and fulfill the zero waste rejection if it is applied in the factory.

寻求具有识别重金属离子功能和电位响应功能的智能离子交换功能膜材料，并用于电控离子交换与电渗析耦合技术分离回收废水中重金属离子，是解决电控离子交换的连续操作性差和电渗析的能耗高、膜易污染等问题的重要途径。本项目以原位包埋有变价金属络合物的苯胺（或吡咯）与吡啶二甲酸共聚复合体系（PAPV）为研究对象，基于目标重金属离子与PAPV膜中有机配体的相互作用力特点，通过调变探针式离子交换功能基元微结构来提高识别重金属离子能力和离子交换容量；通过调谐变价金属络合物的含量来提高膜的协同泵送离子效率。利用电位驱动并控制PAPV膜中所含质子在导电骨架与离子交换基元间往复流动形成活塞效应，选择性捕获和释放目标重金属离子，实现离子的泵送过程。重点研究纳米-亚微米尺度下三维结构膜的离子交换基元微结构调控原理、成长动力学、界面电荷与离子传递机理和耦合泵送机制，为耦合去除重金属离子实现零排放技术的实际应用奠定理论基础。

该课题研究过程中制备出了具有识别重金属离子功能和电位响应功能的智能离子交换功能膜材料，如聚吡啶二甲酸、聚苯胺/磷酸锆、聚吡咯/类普鲁士蓝及原位离子印记的聚吡咯/铁氰根等一系列电活性膜材料。基于目标重金属离子与膜中有机配体的相互作用力特点，通过调整制备方法及条件提高了选择性和离子交换容量。通过物理化学方法阐明了电位响应质子自交换效应及电位驱动质子定向流动并控制电活性膜中所含质子在聚苯胺导电骨架与磷酸锆之间往复流动形成活塞效应。并得到了选择性捕获和释放目标重金属离子，实现离子的泵送过程的机理。同时也研究在多尺度下三维结构膜的结构调控并阐明了调控原理、成长动力学、界面电荷与离子传递机理等科学问题，为耦合去除重金属离子实现零排放技术的实际应用奠定理论基础。