基于两性胶体纳米粒子聚酰胺纳滤膜的制备与性能研究

Improving the water permeability and antifouling property of nanofiltration membranes is the hot and key research topic in this field. Zwitterionic polymers have good hydrophilicity and strong antifouling property.In this project,zwitterionic colloid nanoparticles (ZCNPs) based on zwitterionic monomer and 2-hydroxyethyl acrylate were synthesized via emusifier-free emulsion polymerization by empolying N,N'-Methylenebisacrylamide as crosslinking reagent. ZCNPs with tunable compositions, structures and properties were obtained by tailoring the polymerization and dispersion conditions. Novel polyamide nanofiltration membranes incorporated with ZCNP nanoparticles were prepared by interfacial polymerization. Effects of chemical compositions and structures of ZCNPs, and interfacial polymerization conditions on the morphology of polyamide membrane were studied to obtain nanofiltration membranes with high permeability and antifouling property. The relationship between the ZCNP structrue, the membrane structure and performance was studied, and the high permeability and selectivity principle, and the antifouling mechanism of nanofiltration membrane were probed. This project provides a new route to design high performance nanofiltration membranes and promote the development of nanofiltration technology in water treatment and separation of applications, and is of significant scientific and practical value.

提高膜通量和耐污染性是纳滤分离领域的研究热点和关键问题。本项目基于两性胶体粒子独特的纳米结构，良好的亲水性和耐污染性，从纳米粒子的设计出发，以甜菜碱两性离子单体和丙烯酸-2-羟乙基酯为主要功能单体，N,N'-亚甲基双丙烯酰胺为交联剂，通过无皂乳液聚合法制备两性胶体纳米粒子(Zwitterionic colloid nanoparticle,ZCNP)，研究聚合条件和溶液分散条件对其化学组成、结构和性能的影响。以ZCNP为纳米改性材料，由界面聚合法制备含两性胶体纳米粒子的聚酰胺纳滤膜。通过调节ZCNP粒子组成、结构及界面聚合条件，调控膜结构，获得高通量耐污染聚酰胺纳滤膜。研究ZCNP粒子结构、膜结构及其性能间的内在联系，探索纳滤膜高渗透选择性机理和耐污染机制。本项目的研究不仅为制备高性能纳滤膜提供一种新思路，而且有利于推动纳滤技术在水处理和分离应用领域的发展，具有重要的科学和实际意义。

本项目基于两性纳米粒子良好的亲水性、耐污染性和结构可控性，采用无皂乳液聚合和离子交联法合成了新型两性聚电解质纳米粒子，进而由界面聚合法，制备基于两性聚电解质纳米粒子的聚酰胺纳滤膜，通过调控纳米粒子结构和制膜条件，获得了兼具有高渗透选择性和耐污染性的纳滤膜。纳米杂化膜的水通量为63.8 L.m-2.h-1，是原始聚酰胺膜水通量（35.2 L.m-2.h-1）的2倍，且对无机盐具有良好的分离选择性。在此基础上，采用溶液涂敷－化学交联法，制备了基于两性聚电解质纳米粒子的交联膜，通过调节聚合物化学组成和料液pH值，获得了分离性能可控的适用于有机物和无机盐分离的纳滤膜。采用正电子湮灭技术对膜的微观结构进行分析，建立了两性纳米粒子结构～膜结构～纳滤性能的内在关系，阐明了两性纳米粒子自身亲水性及其在膜内形成的“纳米水通道”结构是膜具有高渗透选择性的根本原因。另外，通过原位离子交联法制备了碳纳米管杂化聚电解质纳滤膜。本项目的研究为制备高性能纳滤膜提供新思路和研究基础，具有重要的科学和实际意义。