Graphene oxide (GO) has made its way to more than 500 peer-reviewed journal articles in 2017, demonstrating a variety of membrane technology applications. Out of the 500 papers, about 80 have investigated the use of graphene oxide for filtration applications (Figure 1). Research on graphene oxide has been a rapidly growing field since 2012, when Nair et al. first demonstrated that GO membrane allows unimpeded permeation of water while blocking all other compounds in the vapor phase.1
Graphene oxide membranes have been extensively investigated for water desalination, oil-water separation, gas separation and pervaporation applications. This material is also being developed into commercial membrane products. G2O is a UK-based company with a patent to utilize graphene oxide membranes to separate oil from water. This technology is applied in the oil industry to create fresh water from seawater. G2O is currently working with a number of industry and innovation partners to scale up and bring this technology to market.2
Why graphene oxide?
Due to its high mechanical strength and chemical inertness, nearly frictionless surface, and cost-effective production in solution, GO plays strongly as a nanomaterial for the fabrication of novel separation membranes. Membranes made from graphene oxide have been shown to be capable of sieving out small nanoparticles, organic molecules, and even large salts.3
In comparison with other available membrane materials, the ease in making atomically-thin GO layers with uniform pore size distribution provides an edge over other membrane materials for practical applications. The resulting graphene oxide membrane, being much thinner than existing polymeric membranes, could achieve a much higher permeate flow with lower energy requirements.
Where is research headed for graphene oxide membranes?
One of the obstacles preventing widespread application of graphene oxide membranes for water desalination is that the membranes swell when immersed in water; this enlargement of the pores enables small salts such as sodium chloride to flow through. Low durability and stability of graphene oxide membranes is another challenge to overcome in various applications.
To address these issues, current research is developing means of controlling membrane channel size and improving the durability of the membrane.4 Additionally, a deep understanding of water and ion transport through graphene oxide membranes is required to achieve appropriate and tunable membrane performance when being applied to desalination, pervaporation and other fields.
 J. Abraham, K.S. Vasu, Ch. D.Williams, K.Gopinadhan, Y.Su, Ch. T.Cherian,...R.R. Nair, “Tunable sieving of ions using graphene oxide membranes”, Nature Nanotechnology, 2017, 12, pp 546–550.
 M.Fathizadeh, W.L. Xu, F.Zhou, Y.Yoon, “Graphene Oxide: A Novel 2-Dimensional Material in Membrane Separation for Water Purification”, Advanced Materials Interfaces, 2017.
 W.L. Xu, Ch. Fang, F.Zhou, Z.Song,† Q.Liu, R.Qiao and M.Yu, “Self-Assembly: A Facile Way of Forming Ultrathin, High-Performance Graphene Oxide Membranes for Water Purification”, Nano Letters, 2017.