Fabrication of graphene oxide-based membranes and their applications in water treatment

Membrane separation is at the forefront of the technologies for desalination and wastewater treatment. However, current membranes have inherent limitations, including permeability/ selectivity trade-off and fouling susceptibility. To overcome these limitations, a new generation of advanced membranes based on nanomaterials has emerged. Among the nanomaterials, Graphene Oxide (GO) is regarded as the most promising nanomaterials due to its favorable characteristics such as hydrophilicity, tunable surface chemistry, large surface area, mechanical stability, bacteriostasis, and biocidal activities. There are currently three types of graphene-based membranes, i.e., nanoporous graphene/GO, laminated GO, and mixed matrix membranes. The fabrication, applications, and limitations of the three classes of membranes are analyzed. After a brief introduction to membranes, graphene, GO, and GO functionalization, the recent advances in the fabrication of these membranes are present-ed. Relevant applications of these membranes in water treatment are discussed in light of the structure-performance relationship. Finally, the overall conclusion and our perspective on future research directions are provided.