Compost is a great use for spent coffee grounds, but what about combating climate change? Scientists have developed a new treatment for coffee grounds that allows them to absorb the greenhouse gas methane.

The process, which is detailed in the journal Nanotechnology, involves soaking the coffee grounds in a simple solution commonly found in home oven cleaners and then heating them to more than 700 degrees Celsius in a furnace. This turns the coffee grounds into methane sponges that could one day be used to help keep this key carbon source out of the atmosphere and even use it in natural gas fuel cells.

"The big thing is we are decreasing the fabrication time and we are using cheap materials," said study co-author Christian Kemp, of Pohang University of Science and Technology, Korea, in a statement. "The waste material is free compared to all the metals and expensive organic chemicals needed in other processes. In my opinion, this is a far easier way to go."

Coffee grounds are apparently such great absorbents that the scientists were able to remove the filtering and washing step normally required to "activate" the carbon in a material. Activated carbon or activated charcoal is an absorbent material that is commonly used to mop up the toxins in people who have overdosed on drugs or ingested some sort of poison.

The "activation" part refers to the process of heating and treating that makes carbon-containing materials such as coffee grounds more absorbent. In the case of coffee grounds, soaking in that simple solution of sodium hydroxide before heating is sufficient to activate the carbon.

This cheap and fast new way of capturing methane could facilitate its use in fuel cells by providing a stable way in which to store this natural gas.

Photo: Matthew Hamm | Flickr