Could a filter made of graphene solve the water crisis?

Researchers from Monash University and the University of Kentucky have developed a graphene-based filter that they believe could be the key to managing the global water crisis. The device can filter out anything bigger than one nanometre and could be used to filter chemicals, viruses or bacteria, with potential applications purifying water, dairy products or wine, or in the production of pharmaceuticals.

Graphene is a lattice of carbon atoms so thin it’s considered to be two-dimensional. It has been hailed as a ‘wonder material’ because of its incredible performance characteristics and range of potential applications. However, this is the first time that a graphene filter has been able to be produced on an industrial scale, as they have previously been difficult and expensive to produce.

“Graphene-based membranes demonstrating ultrafast water transport, precise molecular sieving of gas and solvated molecules shows great promise as novel separation platforms; however, scale-up of these membranes to large areas remains an unresolved problem,” the study authors wrote in the journal Nature Communications.

The leader of the research team, Associate Professor Mainak Majumder from Monash University, said the key to making the filter was developing a viscous form of graphene oxide that could be spread very thinly with a blade. He explained, “This technique creates a uniform arrangement in the graphene, and that evenness gives our filter special properties.”

The device is said to filter liquids nine times faster than the current leading commercial product. It is also so strong and stable that it can be used for extended periods in the harshest corrosive environments, and with less maintenance than other filters on the market. Most importantly, the new technique allows the filters to be produced much faster and in larger sizes, which is critical for developing commercial applications.

The team’s research was supported by industry partner Ionic Industries, as well as a number of Australian Research Council grants. Ionic Industries CEO Mark Muzzi said the next step is to get the filter on the market, noting, “We are currently developing ways to test how the filter fares against particular contaminants that are of interest to our customers.”

The research has so far gathered interest from a number of companies in the United States and the Asia–Pacific region. It has been hailed as a commercial breakthrough by co-author Professor Dibakar Bhattacharyya from the University of Kentucky, who praised its ability to control the thickness of the filter and attain a sharper cut-off in separation, as well as the use of water as the casting solvent.

Image caption: Stable dispersions of graphene oxide which have been concentrated by adding hydrogel beads.