Scientists have formulated a new membrane engineering that makes it possible for for much more efficient removal of carbon dioxide (CO2) from blended gases, these kinds of as electricity plant emissions.
“To display the ability of our new membranes, we seemed at mixtures of CO2 and nitrogen, mainly because CO2/nitrogen dioxide mixtures are significantly relevant in the context of decreasing greenhouse gasoline emissions from electricity crops,” claims Loaded Spontak, co-corresponding author of a paper on the study. “And we’ve shown that we can vastly make improvements to the selectivity of membranes to remove CO2 whilst retaining comparatively significant CO2 permeability.”
“We also appeared at mixtures of CO2 and methane, which is critical to the all-natural fuel field,” claims Spontak, who is a Distinguished Professor of Chemical and Biomolecular Engineering and Professor of Materials Science & Engineering at
A longstanding challenge for such membranes has been a trade-off between permeability and selectivity. The higher the permeability, the more quickly you can move gas through the membrane. But when permeability goes up, selectivity goes down – meaning that nitrogen, or other constituents, also pass through the membrane quickly – reducing the ratio of CO2 to other gases in the mixture. In other words, when selectivity goes down you capture relatively less CO2.
The team of researchers, from the U.S. and Norway, addressed this problem by growing chemically active polymer chains that are both hydrophilic and CO2-philic on the surface of existing membranes. This increases CO2 selectivity and causes relatively little reduction in permeability.
“In short, with little change in permeability, we’ve demonstrated that we can increase selectivity by as much as about 150 times,” says Marius Sandru, co-corresponding author of the paper and senior research scientist at SINTEF Industry, an independent research organization in Norway. “So we’re capturing much more CO2, relative to the other species in gas mixtures.”
Another challenge facing membrane CO2 filters is cost. The more effective previous membrane technologies were, the more expensive they tended to be.
“Because we wanted to create a technology that is commercially viable, our technology started with membranes that are already in widespread use,” says Spontak. “We then engineered the surface of these membranes to improve selectivity. And while this does increase the cost, we think the modified membranes will still be cost-effective.”
“Our next steps are to see the extent to which the techniques we developed here could be applied to other polymers to get comparable, or even superior, results; and to upscale the nanofabrication process,” Sandru says. “Honestly, even though the results here have been nothing short of exciting, we haven’t tried to optimize this modification process yet. Our paper reports proof-of-concept results.”
The researchers are also interested in exploring other applications, such as whether the new membrane technology could be used in biomedical ventilator devices or filtration devices in the aquaculture sector.
The researchers say they are open to working with industry partners in exploring any of these questions or opportunities to help mitigate global climate change and improve device function.
Reference: “An Integrated Materials Approach to Ultrapermeable and Ultraselective CO2 Polymer Membranes” by Marius Sandru, Eugenia M. Sandru, Wade F. Ingram, Jing Deng, Per M. Stenstad, Liyuan Deng and Richard J. Spontak, 31 March 2022, Science.
The paper, “An Integrated Materials Approach to Ultrapermeable and Ultraselective CO2 Polymer Membranes,” is published in the journal Science. The paper was co-authored by Wade Ingram, a former Ph.D. student at NC State; Eugenia Sandru and Per Stenstad of SINTEF Industry; and Jing Deng and Liyuan Deng of the Norwegian University of Science & Technology.
The work was done with support from the Research Council of Norway; UEFSCDI Romania; the National Science Foundation, under grant number ECCS-2025064; and Kraton Corporation.