氧化石墨烯改性对陶瓷微滤膜高效油水分离行为的作用机理研究

Ceramic membrane technology has been developed rapidly in the oily wastewater treatment, while there are some key technical problems in the separation process, such as: the lower separation efficiency due to membrane fouling. Nowadays, the membrane modification has become the effective way and trend to solve the above technical problems. In our previous works, the separation efficiency of ceramic membrane was increased in the oil-water separation process by graphene oxide modification, and we obtained the modified alumina ceramic microfiltration membrane with the high efficiency oil-water separation behavior (such as: high water permeate flux, high oil rejection). However, there is a lack of understanding of the modification mechanism, which affects the development of membrane modification technology. In this project, from the point of view of the modified coating surface characteristics and structure changes of membrane channels, by regulating the hydrophilic or hydrophobic and charging performance of graphene oxide, we explore the effect of these performances of graphene oxide and the membrane pore size and porosity on the oil-water separation behavior of the membrane. We understand the key factors affecting the oil-water separation behavior of the membrane, and explain the mechanism of graphene oxide modification on the high efficiency oil-water separation behavior of membrane, and establish the mathematical equations for describing the oil-water separation behavior of the modified membrane. The results of this project can provide the basis for forming the novel high-efficient ceramic membrane modification technology.

陶瓷膜在含油废水处理过程中，存在易被污染而导致其分离效率偏低等关键问题，膜改性则是解决上述问题的有效方案和重要发展趋势。已有工作通过氧化石墨烯改性，虽然解决了陶瓷膜在油水分离过程中分离效率偏低的问题，获得具有高效油水分离行为（如：高水渗透通量、高油截留率）的改性氧化铝陶瓷微滤膜，但仍存在对氧化石墨烯改性作用机理认识不足的问题，从而制约了膜改性技术的发展。本项目从膜通道内改性涂层表面特性以及膜通道结构变化的角度，拟通过调控氧化石墨烯表面的亲水或疏水和荷电性能，揭示氧化石墨烯表面物化性能以及改性前后膜孔径尺寸和孔隙率对膜油水分离行为的影响规律，明确影响改性膜其高效油水分离行为的关键因素，从而达到解析氧化石墨烯改性作用机理，并构建适用于描述改性膜油水分离行为的数学方程的目的。本项目研究成果可为新型高效陶瓷膜改性技术的形成奠定基础。

在含油废水处理过程中，陶瓷膜存在易被污染而导致其分离效率偏低等关键问题，解决上述问题的有效策略则是膜改性技术。本项目采用改进的Hummers法，制备氧化石墨烯新材料。结合材料性能功能化设计，借助二维结构缺陷调节和物理化学还原等策略，实现了氧化石墨烯的表面润湿性能和荷电性能的可控。同时采用真空迁移法，通过优化调控相关改性技术参数，制备了微结构和性能可控的氧化石墨烯改性涂层，获得了具有不同通道表面特性和通道结构的氧化石墨烯改性膜，并将其应用于纯水渗透和油水分离过程。系统阐明了具有不同表面物理化学性能的氧化石墨烯改性涂层以及改性后的膜孔径尺寸及分布对膜纯水渗透性能和膜油水分离行为（如：水渗透性能、油截留率等）的影响规律。在此基础上，结合微/纳流体流动特性和相关理论，从边界滑移、毛细作用、双电层效应以及多场耦合等多个角度，解析了氧化石墨烯改性对膜高效油水分离行为的作用机理，并构建了适用于描述改性膜油水分离行为的数学方程。本项目研究成果促进了新型高效陶瓷膜改性技术的形成。