静电纺复合膜的自组装原位接枝改性制备及其在纳滤性能研究

Shortage of freshwater resources and water pollution are the challenge of economic development. Recently, membrane separation technology with high rejection rate and high water flux under lower on-stream pressure attracts widely consideration, especially the nanofiltration (NF). However polymer NF membranes are usually made by L-S phase transformation method. These membranes are of large thickness and lower porosity. Moreover, these pores are so closed that makes them are vulnerable to pollutants, resulting the decreased rejection rate and water flux. Besides, the separation membranes should have selectivity for the various objects. Therefore, in order to effectively raise the rejection rate and water flux of NF, improving the membrane structure and tuning the separating function are the key and critical points in the research of NF. In the current research, using electrospun nanofibers as supporting layer，by self-assembly in suit to graft the polyelectrolyte layer even and stably on the surface of electrospun nanofiber membranes, which can hold back the object pollutants effectively. And these electrospun nanofiber membranes can be fabricated continuously. Furthermore, the mechanism of the raised water flux by electrospun supporting layer would be studied. The influence of polymer component, the thickness of separating layer and surface functional group on the rejection rate for complex objects would be studied as well. This research can lay the foundation of developing electrospun nanofiltration membranes with high efficiency and low energy consumption.

淡水资源紧缺和水体污染已成为当今经济发展面临的难题。近年来膜分离技术，尤其是低压操作条件下，实现高截留率高通量的纳滤广受关注。但常规高分子纳滤膜多采用相转化法，所得膜厚度大、孔隙率小且所形成的微孔为闭孔结构，导致膜表面的微孔易被堵塞而降低截留率和水通量。此外，针对不同目标物，分离膜应具有很强的选择性。因此改善膜结构，调控分离层功能，从而有效提高纳滤膜的截留率和水通量是目前纳滤研究中的难点。本申请提出以高分子电纺纳米纤维为支撑层，采用自组装原位接枝法将对复杂目标物有优良脱除效果的聚电解质层均匀且稳固地叠加在高分子电纺纳米纤维上，制备出宏观可操作且高效截留吸附目标物的纳米纤维复合纳滤膜，研究电纺纳米纤维支撑层孔结构提高水通量的机理，研究纳米纤维复合纳滤膜中聚合物组分、分离层厚度、表层官能团等因素对复杂目标物脱除性能的影响，为开发基于电纺纳米纤维膜的高效、低能耗纳滤膜材料奠定基础。

淡水资源紧缺和水体污染已成为当今经济发展面临的难题。近年来膜分离技术，尤其是低压操作条件下，实现高截留率高通量的纳滤广受关注。但常规高分子纳滤膜多采用相转化法，所得膜厚度大、孔隙率小且所形成的微孔为闭孔结构，导致膜表面的微孔易被堵塞而降低截留率和水通量。此外，针对不同目标物，分离膜应具有很强的选择性。因此改善膜结构，调控分离层功能，从而有效提高纳滤膜的截留率和水通量是目前纳滤研究中的难点。本项目主要采用静电纺丝技术和层层自组装技术制备电纺纳米纤维复合膜，所用高分子聚合物主要有PET、PVA、PA6和PAN等，有机结合多种类、多组合的聚电解质，将聚电解质层均匀且稳固地叠加在高分子电纺纳米纤维上，从而制备出可截留吸附多种金属离子的复合纳米纤维膜，主要通过对[CTS/SA]c/l-PET膜、[CTS/SA]c/l-PVA膜、[GO/CTS]c/l- PA6膜、[PDDA/GO]-PAN膜、[PAA/PDDA] -PA6膜及CHI/ALG-PET膜、 PES 复合纳滤膜等复合纳米纤维膜的制备与性能展开研究，详细介绍了各类复合纳米纤维膜的制备、表征及过滤性能等,较好的实现了纳米纤维膜既能去除水体中的重金属离子，又能去除盐离子的双功能化。主要采用SEM、XRD、ICP等多种手段对其进行形貌、成分和性能进行了表征，建立了模拟过滤装置，获得了具有较好机械强度、良好自支撑功能的纤维膜制备工艺技术。该研究为开发基于电纺纳米纤维膜的高效、低能耗纳滤膜材料奠定了一定的实验基础。