两性离子与酶共修饰二硫化钼膜的构筑与水处理研究

Aqueous micropollutants (e.g. phenols) are hazardous while hardly to be removed. Although widely used for water treatment due to its high efficiency and energy saving, the conventional membrane separation method needs to be further improved to effectively remove the micropollutants. Various micropollutants could be degraded by oxidase (e.g. laccase) and further polymerized to obtain a high membrane rejection, thus making it meaningful to prepare biocatalytic membranes. Meanwhile, the stability and reusability of the enzyme are enhanced by the immobilization using membranes. To solve the problem of easy-fouling in conventional biocatalytic membranes, and elevate the micropollutant degradation, rejection and water permeation, this project is proposed to construct ultrathin molybdenum disulfide membranes and explore the manipulation methods of exfoliation and assembly of molybdenum disulfide. After the construction of molybdenum disulfide membranes, bioinspired adhesion and covalent crosslinking are used to modify membrane surface with zwitterion to offer the membrane surface with high hydrophilicity and corresponding antifouling property. And the enzyme is immobilized through similar methods to offer the membrane surface with biocatalytic property. Accordingly, molybdenum disulfide membranes synchronously modified by zwitterion and enzyme are constructed. The bulk channel structure and surface structure of the membranes are controlled, furthermore, the structure-property relationship in the membranes is surveyed to synergistically strengthen the micropollutant degradation process and membrane separation process employing phenols solution as a model system. Hopefully, the implementation of this project could provide references for the design and preparation of high-performance antifouling biocatalytic membranes for micropollutant removal in water treatment.

水中酚类等微污染物危害大、去除难度高，膜分离是一种广泛使用、高效、节能的水处理技术，但传统分离膜对微污染物去除效率有待提高。漆酶等氧化酶可高效降解多种微污染物并使其形成低聚物，将其与膜分离耦合制备生物催化膜有望提高脱酚效率；同时利用膜实现酶的固定化，有利于酶的稳定性且易于回用。为解决传统生物催化膜易污染问题，提高污染物转化截留效率和水通量，本研究拟首先构筑超薄二硫化钼膜，探索二硫化钼的剥离与组装行为调控方法；在此基础上，利用仿生粘合、共价交联等方法，实现膜表面两性离子化，赋予膜表面高亲水性及相应抗污染性；并进行酶固定化，赋予膜表面生物催化功能，从而构筑两性离子与酶共修饰二硫化钼膜；同步调控膜主体通道结构及表面结构，研究膜内构效关系，以酚水溶液为代表物系，实现微污染物催化转化与膜分离过程的协同强化。期望通过本项目的开展，为高性能抗污染生物催化膜的设计制备及微污染物去除相关水处理研究提供参考。

随着工业化的快速发展，水资源短缺和水污染问题日益制约着人类社会的发展。膜技术在废水处理中发挥着越来越大的作用，针对特殊物系的膜设计制备是一个重要研究领域。本项目针对传统膜分离难以去除微污染物及难以实现染料废水回用的问题，开发了一系列新型分离膜。通过引入多孔有机笼作为水相单体实现膜孔径的有效调控，获得疏松界面聚合膜，水渗透通量为52.55 LMH/bar，是PIP/TMC的5.2倍，同时具有优异的盐染选择性。利用戊二醛梯度交联含两性离子聚合物PEI-SBMA，并利用单宁酸调控膜表面荷电性，膜具有优异的纯水通量118.5 LMH/bar，选择性达到未交联时的7.2倍。制备了基于MoS2的抗污染纳滤膜，其对细菌、蛋白、多糖等都有优异的抗污染性。将漆酶添加到MoS2、GO等膜基质中制备生物催化膜，膜的双酚A去除率可达95.3%，对其他多种酚类也具有良好的去除效果，具有较高的储存稳定性和重复使用性，同时也具有较好的盐染选择性。本项目的实施取得了较好的研究成果，对疏松纳滤膜、生物催化膜制备，膜材料、方法、膜结构调控，染料/盐选择性分离、微污染物去除应用等方面均具有借鉴意义。