基于辐射氧化“刻蚀”法制备“智能”多孔氧化石墨烯复合膜

Laminated GO-based membranes assembled using micrometer-sized GO sheets exhibit distinguished characteristics, including hydrophilism, outstanding mechanical strength and good flexibility, which make GO an ideal candidate for nanoscale filtration and sieving applications. However, the permeation of these GO membranes remains insufficient to allow them to compete with commercial ultrafiltration membranes because these membranes are limited by their less fluidic channels and the slow diffusion process therein. Furthermore, by altering the intersheet spacing of these GO membranes, they are expected to perform gradient separation, which is crucial for their application in industrial waste water disposal. In this project, ‘intelligent’ polyacrylic acid (PAA) /nanoporous graphene oxide films with high permeation and gradient separation ability are fabricated. First, nanoporous graphene oxide sheets are prepared using OH· radicals as etchers, which could afford more fluidic channels in the prepared membranes and increase diffusion process therein. Then, pH-responsive polymers PAA are covalently crosslinked nanoporous graphene oxide by esterification reactions to ‘intelligently’ adjust intersheet spacing of the membranes. By exploring the proper ‘etching’ reaction mechanism of nanoporous graphene oxide, fabrication method and characteristics of PAA /nanoporous graphene oxide films, these ‘intelligent’ films are expected to be a potential candidate for the extraction of valuable solutes from complex mixtures. The results of this project will be crucial to provide a new angle of view for developing advanced approaches for fabricating graphene oxide-derived materials. It will also be helpful to promote the further application of GO membranes by providing scientific and experimental basis.

层状排列的氧化石墨烯（GO）膜因其独特的性质有望成为“新一代”高性能选择性分离膜材料。如何提高GO膜的通量和选择性是实现其应用必须解决的两个关键问题。本项目结合辐射法和酯化法，制备高通量、高选择性的“智能”多孔GO复合膜。首先采用辐射氧化“刻蚀”法，可控制备具有纳米孔洞的多孔GO。再利用酯化法将pH敏感的聚丙烯酸（PAA）插入多孔GO片层之间，制备多孔GO/PAA复合膜。多孔GO为复合膜提供新的纵向运输通道，增大膜通量。PAA赋予复合膜随pH可控调节层间距的“智能”，可实现膜对不同尺寸分子的“梯度”分离。因此，“智能”多孔GO/PAA复合膜有望实现污染物的分段处理和回收利用，在复杂的工业废水处理领域具有潜在应用。通过本项目对GO“刻蚀”反应及其机理，“智能”多孔GO/PAA复合膜的合成路线及复合膜通量和“梯度”分离性能的系统研究，拓展利用辐射法制备基于GO的先进分离膜材料的新方法。

通过本项目的研究，成功实现 GO 纳米结构的设计与调控制备多孔 GO，并阐明辐射氧化“刻蚀”法制备多孔 GO 的机理。制备稳定的“智能”多孔 GO/PAA 复合膜，并掌握 PAA 对复合膜层间距的“智能”调控行为。掌握复合膜的通量和“梯度”分离性能，成功构筑多孔 GO 的纳米结构、PAA的修饰量与复合膜性能之间的关系模型，制备一种高通量、高选择性的“智能”多孔 GO/PAA 复合膜。