单价选择性离子交换膜的制备及其在海水淡化副产浓海水制盐中的应用基础研究

The reclamation of the concentrated seawater,the by product from seawater desalination,embraces outstanding social and economical benefits.Now,the salt extraction by means of the electrodialysis based on the mono-valent ion selective ion-exchange membrane attracts more attention.Thus, it is hoped that a breakthrough can be achieved on the membrane fabricating materials and technique for improving the membrane properties. In this project,a new way is proposed after an intensive analysis on the present dilemma. That is, the chitosan is selected as the functional materials and the techniques for membrane structure integration including the embedded dip coating and the immobilization by nitrene insertion are attempted.In addition, the hydroxyl and the amino groups of the chitosan are used as the active sites for the subsequent cross-linkage and functionalization. Based on the grasp on the relation between the membrane fabricating conditions,membrane structure and properties, the influences of the physical and chemical characteristics of the functional layer and the working conditions of the electrodialysis on the membrane properties,such as electrical resistance, electro-osmosis and concentration diffusion,etc.,selective permeation, current efficiency, energy consumption, the maximum concentration and purity are investigated. Furthermore, the competing transport phenomena and the selective separation mechanism should be explored throughly. At last, the advice on the design of the electrodialyzer and the determination of the technological parameters will be proposed. Of course, the success of this project will pave the road for the development of the related membrane, such as the anti-fouling ion exchange membrane and bipolar membrane.

海水淡化副产浓海水的资源化具有显著社会效益和经济效益。其中，利用基于单价选择性离子膜的电渗析制盐备受关注，迫切要求膜功能化材料和工艺的突破提升膜综合性能。本项目瞄准当前单价选择性离子膜制备所面临的主要问题，提出以壳聚糖为功能化材料母体，以内嵌式浸涂和氮烯插入固定化实现功能层/基膜"一体化"，以羟基为交联活性位强化固着作用并调控致密度，以胺基为功能化活性位赋予和调控膜选择分离性能的制膜新思路。在把握制膜条件与膜结构和性能对应关系的基础上，以浓海水电渗析制盐为背景探究功能层的物理、化学特征和电渗析工况与膜的基本性能（如电阻、电渗和浓差扩散等）、极限电流密度、选择分离性能、电流效率、能耗、浓缩浓度和纯度等的内在联系，理解离子跨膜竞争传递现象和膜选择分离机理，进而为浓缩制盐电渗析器的设计和工艺设计参数的确定方案等提出建议。本项目的制膜策略也为耐污染离子膜和双极膜的研制提供借鉴。

海水淡化副产浓海水的资源化具有显著社会效益和经济效益。其中，利用基于单价选择性离子膜的电渗析制盐备受关注，迫切要求膜功能化材料和工艺的突破提升膜综合性能。本项目严格按照研究计划，以壳聚糖和聚乙烯亚胺等为功能化材料母体，采用内嵌式浸涂、氮烯插入固定化以及共价键诱导的自组装等技术实现了功能层与基膜的“一体化”，成功开发了系列可以同时有效用于均相离子交换膜和异相离子交换膜，阳离子交换膜和阴离子交换膜的单价选择性改性方案。过程中较为系统地把握了制膜条件与膜结构和性能对应关系，探究了功能层的物理、化学特征和电渗析工况与膜的基本性能（如电阻、电渗和浓差扩散等）、极限电流密度、选择分离性能、电流效率、能耗、浓缩浓度和纯度等的内在联系，理解了离子跨膜传递现象和膜选择分离机理，并为电渗析器的设计和工艺设计参数的确定方案等提出了建议。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论文十三篇，授权发明专利四件，出版译著一部，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。