Selective Mass Transport Properties of Graphene Oxide Lamellar Membranes
Graphene oxide (GO) features a unique structure of sp2 hybridized carbon clusters and rich oxygen-containing functional groups co-existing within a two-dimensional (2D) lattice. Due to energetic favorability, the oxygen functional groups tend to cluster together, leaving the empty sp2 aromatic nanoclusters to form an interconnected percolation pathway. Upon stacking numerous GO nanosheets together to form a macroscopic lamellar membrane, the oxygen functional groups attached on GO basal planes act as pillars to support the unoxidized sp2 percolation pathway on individual layers to form a nanocapillary network by connecting with each other across the whole lamellar structure, which is presumably responsible for transmembrane mass transport. In recent years, the research on mass transport properties of GO-based membranes has received intense interest and significant advancements have been achieved both experimentally and theoretically. In this chapter, we review the recent developments in this burgeoning research field by emphasizing the transport properties of water, dissolved ions and molecules, and gaseous atoms and molecules through GO membranes. Finally, a perspective has been given for future developments.