1 Breakthrough Membrane Captures CO2 From Thin Air (Literally!)
Scientists created a new membrane that captures CO2 from air using natural humidity, avoiding high energy use. This tech could be crucial for achieving climate goals and doesn’t rely on capturing emissions directly at source.
CONTENTS: 1 Breakthrough Membrane Captures CO2 From Thin Air (Literally!)
New membrane captures CO2 from air
1 Breakthrough Membrane Captures CO2 From Thin Air
Direct air capture (DAC) has been highlighted as one of the “seven chemical separations to change the world” due to the difficulty in isolating carbon dioxide from the atmosphere. Carbon dioxide, a major driver of climate change, is released in about 40 billion tons annually, but its atmospheric concentration is only around 0.04%. Prof. Ian Metcalfe, Royal Academy of Engineering Chair in Emerging Technologies at Newcastle University, explains that separating such dilute substances presents significant challenges. The primary issues are the slow rate of chemical reactions needed to remove the dilute component and the high energy requirements to concentrate it.
The Newcastle researchers, along with their collaborators from Victoria University of Wellington, Imperial College London, Oxford University, Strathclyde University, and UCL, have developed a new membrane process to address the challenges of direct air capture. By leveraging natural humidity differences to drive the removal of carbon dioxide from the air, they have tackled the energy issue. Additionally, the presence of water enhances the transport of carbon dioxide through the membrane, addressing the kinetic challenge.
Their findings, published in Nature Energy, highlight the importance of direct air capture for the future energy system. Dr. Greg A. Mutch, Royal Academy of Engineering Fellow at Newcastle University, notes that this technology will be crucial for capturing emissions from mobile and dispersed sources of carbon dioxide that are difficult to decarbonize through other means.
“Our research presents the first synthetic membrane that can capture carbon dioxide from the air and concentrate it without relying on conventional energy sources such as heat or pressure. A useful analogy might be a water wheel in a flour mill. Just as a mill harnesses the downhill flow of water to power the milling process, our system utilizes natural humidity differences to extract carbon dioxide from the air.”
Separation for climate goals
Separation processes are fundamental to many aspects of modern life, affecting everything from the food we consume and the medicines we use to the fuels and batteries in our vehicles. These processes are crucial for minimizing waste and reducing the need for environmental cleanup, such as in direct air capture of carbon dioxide.
As the world shifts toward a circular economy, the importance of separation processes will grow. Direct air capture could play a role in providing carbon dioxide as a feedstock for producing various hydrocarbon products in a carbon-neutral or even carbon-negative cycle.
Most importantly, along with adopting renewable energy and traditional carbon capture technologies at sources like power plants, direct air capture is essential for achieving climate goals, such as the 1.5 °C target set by the Paris Agreement.
Membrane captures CO2 with humidity
Dr. Evangelos Papaioannou, Senior Lecturer at Newcastle University, explains that the research team explored a novel carbon dioxide-permeable membrane under various humidity conditions. Unlike typical membranes, their design used a higher humidity on the output side to drive carbon dioxide into that stream spontaneously.
The team, collaborating with UCL and the University of Oxford, employed X-ray micro-computed tomography to precisely analyze the membrane’s structure, allowing for accurate performance comparisons with other advanced membranes.
A significant aspect of their work involved modeling the membrane’s processes at the molecular level. Collaborating with experts from Victoria University of Wellington and Imperial College London, they identified “carriers” in the membrane that specifically transport both carbon dioxide and water. This interaction is crucial because water is needed to release carbon dioxide from the membrane, and vice versa. Consequently, the energy from a humidity gradient can be harnessed to move carbon dioxide from areas of lower to higher concentration.
Prof. Metcalfe emphasized that the success of this project was due to a collaborative effort over several years and expressed gratitude for the contributions of their partners and the support from the Royal Academy of Engineering and the Engineering & Physical Sciences Research Council.
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