Mechanisms of Selective Mass Transport through Graphene Oxide Membranes
Selective mass transport in the forms of liquids, gases and ions is the fundamental process in filtration and separation applications. Membranes with porous microstructures have been widely applied in, for example, water treatment, gas separation and biomedical engineering. Graphene oxide (GO) membranes feature a layer-by-layer microstructure with embedded nanoscale interlayer galleries, channels, pores and slits that are highly selective for the transport of molecular species, while the atomistically smooth graphene walls allow enhanced slip flow, holding great promise in practical applications by offering high selectivity and permeability. Moreover, fluid–wall interactions and membrane microstructures can be finely tuned by functionalization of the GO sheets and control of their assembly processes. The GO membrane is thus also a model material for mechanistic studies, to elucidate the underlying mechanisms of selective mass transport in nanoscale channels. In this chapter, we will review the current understanding of nanoscale fluidic transport processes in the hierarchical pathway of GO membranes, based on recent theoretical and experimental progress.