New polymer membrane technology efficiently removes carbon dioxide from mixed gases

A group of researchers at North Carolina State University working under a grant to the North Carolina Research Triangle Nanotechnology Network, a site of the NSF National Nanotechnology Coordinated Infrastructure program, has developed a polymer membrane technology that removes carbon dioxide from mixed gases. It could play a role in reducing power plant emissions.

"To demonstrate the capability of our new membranes, we looked at mixtures of CO₂ and nitrogen, because CO₂/nitrogen dioxide mixtures are particularly relevant in reducing greenhouse gas emissions from power plants," said Rich Spontak, corresponding author of the study. "We've demonstrated that we can vastly improve the selectivity of membranes to remove CO₂ while retaining relatively high CO₂ permeability.

"We also looked at mixtures of CO₂ and methane, which is important to the natural gas industry," said Spontak. "These CO₂-filtering membranes can be used in any situation in which one needs to remove CO₂ from mixed gases -- whether it's a biomedical application or scrubbing CO₂ from the air in a submarine."

The selectively permeable membrane works by filtering CO₂ faster than other mixed gases.

The technology started with membranes that are already in widespread use. The researchers then engineered the surfaces of the membranes to improve selectivity.

"Our next steps are to see how these techniques could be applied to other polymers to get comparable, or even superior, results, and to upscale the nanofabrication process," corresponding author Marius Sandru said.

The researchers plan to investigate potential applications for the polymer, including use in ventilation and filtration devices and climate change mitigation.