It achieves this by applying a graphene coating to polymer membranes which dramatically increases membrane performance allowing a greater throughput of water. It also allows new applications and markets for membranes where their performance is affected by contamination, for example where membrane pores are blocked by oil deposits.
G2O is not a membrane manufacturer; instead, its coating is applied to membranes already manufactured and available on the market. Therefore, it allows companies using membranes in water filtration to switch easily to a more effective process without incurring significant additional capital expenditure.
Primary benefits of G2O technology
- Applying the G2O coating gives membranes a unique combination of high flux rates (the amount of water flowing through a membrane) of between 100 and 1000 times more than current ultra-filtration membranes.
- The membranes can recover from contamination without using chemical cleaning and the coating can be tuned to specific applications such as water desalination, oil/water separation, storm water treatment and industrial waste water recovery.
- Initial water flux can be as high as 4400 L/m2.h.bar with excellent superoleophobicity – the ability of a material to repel oil – reducing the clogging of the filter surface with the oil it is trying to filter out.
- Overall, G2O’s patented graphene technology acts as a functional coating, modifying existing filtration membranes, which means:
- Higher pure water flux
- High contamination resistance
- Excellent mechanical strength by coating existing membranes
- High chemical stability: able to withstand water containing aggressive contaminants
- Good thermal stability: able to withstand higher water temperatures without affecting the membrane.
- Low cost
G2O’s technology has the potential to transform the water and environmental industry by reducing energy costs by up to 90%.
Reducing the amount of energy needed in a water purification process – for example, the desalination process requires water pressurised to 70 bar to force it through a membrane – will reduce the overall cost for producing clean water.
When combined with the technology’s ability to reduce contaminants in the filtration process, this provides the opportunity to effectively clean waste water so it can be re-used.
Oil/water separation – using a miracle of nature
In the oil industry, generating a barrel of oil often requires treating 9 barrels of water in the process. Coupled with stricterg environmental regulations, this means that treating water has become a significant factor in oil companies’ production costs.
However, contamination of nano/ultra-filtration membranes in the oil/water separation process is a long-standing problem and a major economic disincentive for using membranes more widely.
Existing membranes typically show severe contamination caused by oil sticking to the membrane surface and/or oil penetrating the membranes. This greatly degrades their performance and shortens service lifetime.
Membranes using G2O’s graphene oxide technology stops contamination, which means the membranes are fully-recoverable and high flux (allowing a large amount of water to flow through the membrane).
This result is achieved by taking a lesson from nature: G2O’s graphene oxide coating behaves in the same way as the scales on a fish. This miracle of evolution allows fish scales to maintain a thin layer of water on the outside of the fish, preventing any contamination from adhering to the fish’s body.
In the G2O oil/water separation process, water passes through the graphene oxide-coated membranes, forming numerous water pockets inside the structure which help to repel oil droplets.
Performance evaluation tests reveal ~100% membrane recovery by flushing its surface with water. This avoids the need to use any other cleaning chemicals – such as acids and alkalis – that reduce the membrane’s lifespan and performance.