We have been concerned about the news of eruption of methane from the floor of the Arctic Ocean, however, the quantities released so far are relatively smaller than what comes out from our waste and landfills. A part of this is captured and burned for clean electricity, however, now graphene might be able to do more than that.
Methane which is produced by anaerobic bacteria breaks down organic material in a lack of oxygen. The most suitable environment for this is the wastewater treatment plants in cities which produce more than 25 million tonnes every year.
Methane is a stronger greenhouse gas than carbon dioxide so capturing and burning it helps from not reaching the atmosphere. We can displace fossil fuels if we are able to fully use the energy generated. Normally the biogas that is collected from waste facilities is impure so it cannot be used on a wide scale.
Dr. Rakesh Joshi, University of New South Wales demonstrated that graphene membranes are more effective in separating methane than the systems currently in use, thus making use of waste methane viable where it is not currently present. Joshi was initially trying to use graphene for helping Sydney Water to improve the water purification process, to remove organic matter from the wastewater to make it fit for drinking. Graphene can remove 99 percent of the impurities which are not detected by other water purifying techniques.
Graphene also helped in the filtering of biogas and it was used for powering the operations of Sydney Water. Graphene membranes are also cheaper than the other options. On burning, methane produces carbon dioxide but it is produced from wastewater by breaking down plants that draw the same amount of carbon from the atmosphere. This makes it a greenhouse neutral energy source that can balance the renewable electricity grids in low sun and wind conditions.
The demonstration has been mainly effective in the scale of the laboratory till now. Dr. Heri Bustamante, Sydney Water said that using graphene will help in the increased capture of methane thus expanding its uses. Methane can ultimately be produced for fuelling buses in the near future.
Researchers are hopeful to ramp up the scale of its use. A near goal in the future is to capture the gases that are produced by natural wetlands and separate methane.