基于迈克尔加成法调控聚酰胺纳滤膜表面微结构与化学构造研究

Nanofiltration (NF) has been widely used in water and wastewater treatment and desalination. Currently the relatively limited types of NF membranes are incapable of meeting the demand of high performance for complex separation systems. Membrane fouling and “trade-off” between permeability/selectivity are two main challenges to the application of NF membrane and design new NF membranes. In this project, a novel strategy to fabricate new types of NF membranes with antifouling properties and outstanding performance is proposed by surface modification polyamide NF membranes with different monomers via Michael addition reaction. Without enhancing the intrinsic membrane hydraulic resistance，the surface morphology and function group of yielding membranes are able to controlled at a molecular-level by choosing the monomers structures. Meanwhile, the NF performance of as-prepared membranes will be investigated for separation monovalent/divalent ions, ion/organic, and organic/organic mixtures systems. Furthermore, the internal relations between NF membrane material, surface properties, and NF performance will be studied. The mechanism between separation performance, antifouling performance, chlorine resistance, and antibacterial properties and surface morphology, and chemical structures will also be illustrated. As a consequence, the knowledge obtained from this project will be provide as a straightforward guide for the preparation of new generation membranes with high separation performance and long-term stability performance. This work provides a new perspective to manipulate the surface morphology and chemical structures of NF membranes, which has promoted NF membranes application in complex separation systems and played a key role in the fundamental research and practical implications.

目前纳滤膜的种类相对单一无法满足日益复杂分离体系的要求，其中膜污染及渗透性/选择性之间的平衡是纳滤膜在使用和研发过程中面临的亟待解决的两个难题。本项目提出一种简单高效制备能够满足不同分离体系纳滤膜的新策略，采用迈克尔加成法对聚酰胺纳滤膜表面进行碳-氮化学键的高效构筑，在分子水平上调控纳滤膜的表面微结构及表面离子化与电中性化，同时解决膜污染及渗透性/选择性之间的平衡这两个难题，丰富纳滤膜的种类，并应用于不同价态盐离子、无机盐/有机物以及不同分子量有机物等的纳滤分离。通过建立纳滤膜材料～膜表面性质～纳滤性能的构效关系，阐明纳滤膜表面微结构与化学构造对纳滤膜分离性、耐污染性能、耐氯性能及抗菌性能的影响，为针对不同分离体系设计制备高分离性能与长期服役的纳滤膜提供理论指导。本研究提出了一种调控纳滤膜表面微结构与化学构造的新策略,推动纳滤技术在复杂分离体系的应用，具有重要的科学意义和应用前景。

随着人口增长，工业化及全球气候变化，水资源紧缺与水环境污染不断加剧。膜分离技术作为一种高效与可持续的技术，能够为人类提供高品质的用水。纳滤是膜分离技术的重要成员，针对不同分离体系开发综合性能优异的纳滤膜十分必要。本项目以通过分子水平调控聚酰胺纳滤膜表面微结构与化学构造获得综合性能优异的纳滤膜为目的，提出使用迈克尔加成反应对纳滤膜进行表面改性的策略。设计并合成了系列邻苯二酚/聚乙烯亚胺胺基功能化纳米粒子，通过遴选常用胺类单体和缺电子烯烃功能化单体，制备了基于迈克尔加成反应改性的高渗透选择性纳滤膜，并考察了相关实验参数对胺基功能化纳米粒子和改性纳滤膜性能的影响。如采用两性离子单体迈克尔加成改性的纳滤膜(SBMA-M15)，水通量为63.54 Lm-2 h-1，是原始纳滤膜水通量(32.40 Lm-2 h-1)的1.96倍，且保持了对无机盐截留性能。采用荷正电单体迈克尔加成改性的纳滤膜（DMC-M15），水通量为原始纳滤膜的2.36倍(76.56 Lm-2 h-1)，对MgCl2的截留率为92.5%。在一定程度上实现了抑制水通量与盐截留率之间的“Trade-off”现象。通过关联纳滤膜材料～膜表面性质～纳滤性能的构效，获得了控制纳滤膜分离性能的关键因素。本研究不仅提出了一种调控聚酰胺纳滤膜表面微结构与化学构造的新策略，而且为制备高性能纳滤膜提供了一定的借鉴意义，具有一定的科学意义和应用前景。