Invention of a membrane capable of extracting carbon dioxide from the air

To combat climate change, direct capture of carbon dioxide (CO₂) from the atmosphere has become a priority. However, due to its low concentration in the air (about 0.04%), separating CO₂ is a complex and energy-intensive task.

In this context, a team of researchers at Newcastle University, UK, has developed a new membrane capable of capturing CO₂ using simply differences in humidity, an advancement that could transform current methods of reducing greenhouse gas emissions.


This innovative membrane works on a principle similar to that of a water wheel in a mill. Instead of using gravity to grind grain, the membrane exploits variations in humidity to extract CO₂ from the air. When the humidity is higher on the output side of the membrane, it naturally draws CO₂ towards that flow. According to Dr. Greg A. Mutch, a member of the Royal Academy of Engineering at Newcastle University, this synthetic membrane is the first to increase the concentration of CO₂ without relying on traditional energy sources like heat or pressure.


Two major challenges in direct air capture are thereby addressed. On one hand, energy efficiency: by using humidity differences as a driving force, the membrane avoids the high energy costs usually required. On the other hand, reaction speed: the presence of water accelerates the transport of CO₂ through the membrane, thus addressing the slowness of processes involving separation of low-concentration components.

CO₂ direct capture is crucial for meeting climate goals, such as limiting warming to 2.7 °F (1.5 °C), established by the Paris Agreement. Professor Ian Metcalfe, lead investigator, points out that separating diluted components is particularly difficult due to low concentration and slow chemical reactions. This new membrane could thus enable a more effective and widespread application of CO₂ direct capture.

The implications of this technology go beyond mere emissions reduction. It could also play a key role in a circular economy, where the captured CO₂ could be reused as a raw material for hydrocarbon production, in a neutral or even carbon-negative cycle.


However, for widespread adoption, further research is needed, particularly to lower the operating temperature of the membrane, which is currently over 752 °F (400 °C). This work by the team at Newcastle University, published in Nature Energy, nevertheless marks significant progress in the field of CO₂ direct capture, paving the way for more sustainable and effective solutions to reduce atmospheric CO₂ levels.

Article author: Cédric DEPOND