基于纳米材料多元协同接枝的超亲水膜改性机制及抗污染机理研究

The widespread application of membrane separation technology has always been hampered due to membrane fouling. Endowing membranes with superhydrophilicity via membrane modification enhances their antifouling performance, which potentially offers a fundamental solution for membrane fouling control. The current project aims to develop a novel and practical strategy for fabrication of enhanced superhydrophilic nanomaterial/polymer composite membranes on the basis of a self-assembly grafting method that was previously proposed by our group. A novel strategy for the fabrication of superhydrophilic membranes based on concerted simultaneous grafting of diverse nanomaterials will be studied. Physicochemical characteristics and fouling behavior of the resultant superhydrophilic membranes will be systematically investigated for analyses of the modification and antifouling mechanisms. At the method level, a simpler version of the existing superhydrophilic modification method will be developed and optimized to enhance its pragmatic value. At the material level, novel superhydrophilic membranes will be fabricated in virtue of concerted simultaneous grafting of diverse nanomaterials, including nano-TiO2, nano-SiO2, and layered-double-hydroxide (LDH) nanosheets. Influence of the combination of the diverse nanomaterials on the modification effect will be investigated. A controllable modification strategy based on tuning nanomaterial combinations will be proposed through systematic characterizations of the resultant superhydrophilic membranes. At the mechanism level, fouling behavior of a typical superhydrophilic composite membrane will be investigated through various fouling tests using model-foulant solutions, municipal and industrial wastewater, and microorganism suspensions to depict the antifouling mechanisms. This project could promisingly provide theoretical and experimental foundations for the development and practical application of superhydrophilic membranes.

膜污染是制约膜法水处理技术进一步发展和应用的瓶颈。对膜进行超亲水化改性以提高其抗污染性能具有从根本上控制膜污染的巨大潜力。在膜表面接枝纳米颗粒是实现膜表面超亲水化的有效途径，但基于单一纳米材料接枝的膜超亲水化效果有限。多元纳米材料协同接枝可以为膜表面提供丰富的理化性质和微/纳结构，具有广阔的发展应用前景，其核心关键是协同接枝机制的解析。本项目在对现有较复杂自组装接枝超亲水化方法进行简化优化的基础上，选用纳米SiO2、纳米TiO2及纳米类水滑石等纳米材料，探究多元纳米材料协同接枝过程中纳米材料之间、纳米材料与膜表面之间的相互作用机制，并系统考察多元纳米材料体系组配、反应条件等对改性效果的影响，解析多元协同接枝的超亲水化调控机制；结合系统的污染行为研究，进一步解析复合超亲水膜的抗污染机理。本项目旨在为超亲水膜的科学研究和推广应用提供理论支持。

膜污染是制约膜法水处理技术进一步发展和应用的瓶颈。对膜进行超亲水化改性以提高其抗污染性能具有从根本上控制膜污染的巨大潜力。本项目从膜表面形貌构筑和化学性质接枝调控等多元化角度，提出一套多元协同超亲水化改性策略，并对其协同改性调控机制进行了系统解析。项目首先基于共混改性和浸覆接枝原理，选取多种富羧基添加剂和纳米SiO2超亲水介质，研发出一种简易高效的超亲水超滤膜制备方法，并优选乙二胺四乙酸为最佳添加剂；其次从膜表面形貌和化学性质协同调控的角度入手，将纳米印铸和纳米热压印技术分别与纳米颗粒浸覆接枝技术相结合，研发出一系列具有多级微纳结构的特种亲水膜制备方法，所得新型复合膜在水通透性、截留能力以及抗污染性能等方面均获得显著提升；随后从多种纳米材料协同接枝的角度入手，提出一种基于纳米SiO2和纳米类水滑石的协同接枝改性技术，研发出一种具有层级微纳结构和非均质化学属性的特种亲水膜，所得膜具有优异的抗不可逆污染性能；最后针对不同种超亲水膜材料，从模型污染物、实际废水以及微生物污染多个角度入手，系统解析了超亲水改性膜的污染行为和抗污染机理，为超亲水膜的实际应用奠定了基础。