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纳滤膜是20世纪80年代末期发展起来的一种广泛用于液体分离的新型分离膜。早期研究中,先后提出的基于筛分效应的细孔模型,基于静电效应的电荷模型,以及同时考虑上述两种效应的静电位阻模型和道南位阻模型等为人们更好地理解纳滤膜分离机理和指导纳滤膜过程应用发挥了十分重要的作用。然而由于这些具有“疏松型反渗透膜”特点的纳滤膜没有相应的膜性能预测评价软件,使得针对具体应用过程的纳滤膜的大规模标准化应用受到了一定的制约。为此,结合上述模型,根据一些特定实验拟合确定混合盐体系同号离子间的竞争作用和异号离子间的调节作用,提出了一个适于混合盐体系的纳滤膜分离性能评价模型,促进了纳滤膜技术在水处理过程的大规模推广。最近,根据纳滤膜对离子选择性分离性能及其伴随的动电性质的细致而深入的实验研究,发现仅考虑筛分效应和静电效应并不能完全合理地解释纳滤膜的分离性能,且在动电性质的解析上也存在一定缺陷,进而对纳滤膜纳米级孔径引起的特殊效应和溶液体系中复杂相互作用引起的荷电性质变化有了更为深刻的认识和理解,提出并定量分析了离子透过纳滤膜时存在的介电排斥效应。
Nanofiltration membrane is a new type of separation membrane widely used in liquid separation developed in the late 1980s. In the early research, the pore model based on the screening effect, the charge model based on the electrostatic effect, the electrostatic potential resistance model and the southern resistance model taking both the above two effects into consideration were proposed for the better understanding of nanofiltration Membrane separation mechanism and guide the application of nanofiltration process has played a very important role. However, since these nanofiltration membranes with “loose reverse osmosis membranes” do not have the corresponding membrane performance prediction and evaluation software, large-scale standardization applications of nanofiltration membranes for specific application processes are constrained. Therefore, in combination with the above model, the competition between different ions in a mixed salt system and the regulation between different number ions are determined according to some experimental fitting. An evaluation model for the separation performance of nanofiltration membranes with mixed salts is proposed. Promote nanofiltration technology in the water treatment process of large-scale promotion. Recently, based on the careful and in-depth experimental study on the selective separation performance of nanofiltration membranes and their accompanying electrokinetic properties, it has been found that the separation performance of the nanofiltration membranes can not be fully explained by considering only the screening effect and the electrostatic effect There are also some shortcomings in the analysis of the electrokinetic properties, and thus a more profound understanding and understanding of the special effects caused by the nano-scale pore size of the nanofiltration membrane and the change of the charging property caused by the complex interaction in the solution system are proposed and quantified The effect of dielectric repulsion existing in the nanofiltration membrane was analyzed.