基于表面超亲水改性的强耐污染高通量反渗透/纳滤膜的设计与便捷制备

The applications of RO/NF processes in effluent treatment are affected by the anti-fouling property significantly. The use of traditional methods to improve the anti-fouling property will result in the decline in permeation flux of membranes. In this project, two strategies including “hydration layer repulsion” and “charge repulsion” were proposed based on the different mechanisms of membrane fouling during effluent treatment. The super-hydrophilicity treatment of membrane surface was realized by facile chemical or physical methods to improve the anti-fouling property significantly and maintain the high permeation flux of membrane simultaneously. Ionic solvation hydration layer, charged nano-composite layer, and charged micro-nano structure layer were designed. Excellent anti-fouling property and high permeation flux were achieved by the use of hydration layer and hydrophilic nanomaterials. The mild construction of ultra-thin ionic solvation hydration layer on membrane surface using zwitterion or ionic liquid via Michael addition was studied. The constructions of charged nano-composite layer and charged micro-nano structure layer via facile mixture and self-assembly methods using different charged nanomaterials. Hence, the facile fabrication method of membrane with excellent anti-fouling property was obtained, and the anti-fouling mechanism was also investigated. Separations membranes with excellent properties were achieved in this project used in the treatments of organic effluent, heavy metal effluent and their mixed effluent.

膜的耐污染性直接影响了RO/NF等过程在废水处理中的应用，传统的耐污染改性方法会导致膜通量下降。本项目基于不同废水造成膜污染的机理，提出“水合层排斥”和“荷电层排斥”两个策略，利用简单的化学或物理方法实现膜表面的超亲水化改性，在提高膜耐污染性的同时保持高水通量。具体为：设计具有离子溶剂化水合层表面、荷电纳米复合层表面、荷电微纳结构水合层表面等三种功能化膜表面结构，利用水合层或亲水纳米材料使膜表面具有超亲水性质，来保证膜同时具有耐污染和高水通量的性能。通过选择强水合作用的两性离子或离子液体为改性剂，研究迈克尔加成等条件温和的化学方法用于表面接枝超薄离子溶剂化分子层的改性；筛选和制备不同荷电型纳米材料，考察简单掺杂和自组装的物理方法用于荷电纳米复合层与荷电微纳结构水合层表面的构建，从而建立起强耐污染膜的便捷制备方法，探明分离机理。为有机废水、重金属离子废水及其混合废水的处理提供高性能的分离膜。

抗污染性能是反渗透和纳滤膜在应用过程中最为关键的性能之一，针对反渗透和纳滤膜超薄表面层易损伤，常规抗污染性能改进易导致膜分离性能下降的问题，本项目从成膜过程调控到膜表面温和改性方法构建等方面进行了系列研究取得了如下成果：1) 提出界面聚合法制备聚酰胺反渗透/纳滤膜的过程本质是“反应-扩散过程”的新论断，构建了“图灵反应-扩散模型”为理论指导的纳滤膜制备过程调控新机理，制备出首张图灵结构纳滤膜；2) 基于两性离子优异的non-fouling性质，利用条件温和的迈克尔加成反应在反渗透和纳滤膜表面分别成功构建了两性离子、类两性离子和离子液体修饰层，实现了表面接枝离子溶剂化分子层耐污染高通量RO/NF膜的便捷制备；3) 采用top-down和bottom-up策略制备了纳米级阴/阳离子型荷电颗粒，在界面聚合反应过程中添加荷电颗粒制备了具有荷电表面的耐污染高通量纳米混合基质膜，分别考察了阴/阳离子型纳米材料的种类、添加量、尺寸和添加方式对膜结构和性能的影响；4)研究这三类RO/NF膜的表面物化性质/本体结构与膜耐污染性/通量之间的协同关系，建立了复杂体系下高通量耐污染膜的耐污染机理及结构-性能关系。本项目提出的通过控制单体扩散定向调控纳滤膜表面结构的研究成果在Science发表后重新激发了对界面聚合制备反渗透和纳滤膜的研究兴趣，国内外多个课题组跟进开展膜表面形貌调控的研究；所设计的基于两性离子层抗污染反渗透膜成功解决了在脆弱反渗透膜表面构建保护层的难题，研究成果获得了2017年国家海洋局海洋科技二等奖。本项目在Science、EST等顶级期刊共计发表SCI论文12篇，他引400余次，授权发明专利2项，获得省部级奖2项。