A new method to pump carbon dioxide out of the air has been developed by scientists from the UK and New Zealand, hitting on an approach that doesn’t require huge amounts of energy. They developed and tested a CO2-permeable synthetic membrane that was designed to “hijack” the energy generated by differences in humidity between dry air on one side of the membrane and humid air on the other side. In the lab, the researchers were able to exploit this energy to pump CO2 out of the air, avoiding the need for an external energy source. The team says this technology could play a part in the huge task of tackling carbon emissions, but more work will be needed to develop and test its application beyond the lab.
Journal/conference: Nature Energy
Link to research (DOI): 10.1038/s41560-024-01588-6
Organisation/s: MacDiarmid Institute, Victoria University of Wellington, Newcastle University, UK; University of Strathclyde, UK; University College London, UK; University of Oxford, UK; Imperial College London, UK
Funder: The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC grant agreement number 320725 (I.S.M.). This work was supported by the Engineering and Physical Sciences Research Council (grant numbers EP/M01486X/1 (I.S.M.), EP/P007767/1 (I.S.M.), EP/P009050/1 (I.S.M., D.J.L.B. and P.R.S.), EP/V047078/1 (I.S.M. and G.A.M.) and EP/W03395X/1 (I.S.M., G.A.M., D.J.L.B. and P.R.S.)). I.S.M. acknowledges funding from the Royal Academy of Engineering through a Chair in Emerging Technologies Award entitled ‘Engineering Chemical Reactor Technologies for a Low-Carbon Energy Future’ (grant CiET1819\2\57). G.A.M. was supported by the Royal Academy of Engineering under the Research Fellowship scheme.
Media release
From: MacDiarmid Institute
Researchers test new way to remove carbon dioxide from airA new method to pump carbon dioxide out of the air has been developed by scientists from the UK and New Zealand.More than 35 billion tonnes of carbon dioxide (CO 2 ), the main contributor to climate change, are released into the atmosphere each year. Scientists investigating ways to “capture” some of this gas have landed on a new method that they believe could see CO 2 extracted from the air and potentially reused in carbon-neutral manufacturing processes.Professor Patricia Hunt, from the School of Chemical and Physical Sciences and an associate investigator at the MacDiarmid Institute, says extracting CO 2 from the air is a “challenging” puzzle to solve.“Some CO 2 can be captured at source—for example, from the smokestacks of factories and power plants that burn fossil fuels. However, once CO 2 is in the atmosphere it’s significantly harder to extract.“The first problem is that air is mostly nitrogen and oxygen, and we need to select and then capture CO 2 , which is only present in tiny amounts—about 0.04 percent. The next step is concentrating the CO 2 , which requires significant energy,” she says.Professor Hunt and researchers from the UK have hit on an approach that doesn’t require huge amounts of energy.They developed and tested a CO 2 -permeable synthetic membrane, a bit like a high-tech filter. The membrane system was designed to “hijack” the energy generated by differences in humidity between dry air on one side of the membrane and wet (humid) air—made wet by the introduction of water—on the other side, she explains.In the lab, the researchers were able to exploit this energy to pump CO 2 out of the air, avoiding the need for an external energy source.“If we think of a hydropower station, we know that water flowing downhill produces energy. In the membrane system we developed, water flowing downwards was used to power the capture of CO 2, allowing it to be concentrated so it could be reused or stored.“For each water molecule going downhill inside the membrane, one CO 2 molecule was stored. This gave us a hint that the two processes were connected. Using computer modelling, we were then able to look at things on a molecular level to pinpoint what was happening.”Co-researcher Dr Greg Mutch, from the UK’s Newcastle University, compared the process to a waterwheel on a flour mill: “Whereas a mill uses the downhill transport of water to drive milling, we use it to pump carbon dioxide out of the air.”Luckily, the researchers didn’t have to construct a flour mill. Their experiments were done in an alumina membrane reactor—a device used to separate different chemicals. Outside the lab, membrane reactors are a common way of treating wastewater by filtering out contaminants. Professor Hunt says the membrane they used looks a bit like a pencil-sized water filter cartridge—one where the CO 2 needs a water molecule and an energy “push” to help it pass through.“Our research has shown that a membrane system can remove CO 2 from the air, without the need for a large external energy source. This technology could play a part in the huge task of tackling carbon emissions, but more work will be needed to develop and test its application beyond the lab,” she said.Results of the research, led by Professor Ian Metcalfe from Newcastle University, are published in Nature Energy.Researchers from the University of Strathclyde, University College London, University of Oxford, and Imperial College London were also involved in the work.