Graphene: Looking beyond the Hype
One area in which Harper thinks graphene materials show particular promise is water purification. He recently founded UK-based company G2O, which has licensed graphene oxide membrane technology developed at the University of South Carolina, US. The water filtration membranes are made by coating a polyamide substrate with flakes of graphene oxide, which overlap and wrap around the polyamide fibres to ‘mimic the mucus layer on top of fish scales’, says Harper. When a mixture of oil and water is exposed to the membrane, the graphene oxide flakes trap water inside the structure, creating hydrophilic pockets that repel the oil. This makes the membrane very resistant to fouling, which is a common problem with most purification membrane technology.
‘Water treatment costs are extremely high at the moment,’ says Harper. ‘But once you start coating these membranes, suddenly the amount of water you can get through increases, and other things don’t foul, and that translates to massive savings. If you look at a typical desalination plant, we can save probably 40% of the energy costs.’ That could save a plant up to $40 million (£26 million) every year, and Harper hopes the figures are promising enough to convince water treatment and desalination companies to fund the scaling-up of this technology.