Northwestern University has pioneered an innovative “moisture-swing” mechanism in the field of direct air carbon capture (DAC), capable of capturing carbon dioxide at low humidity levels and releasing it at higher humidity levels. The method employs various ions and presents a more energy-efficient alternative to traditional carbon capture methodologies.
By capitalizing on humidity-driven technology, the research team identified new ions that support low-energy carbon sequestration processes.
As global initiatives increasingly focus on reducing industrial carbon footprints, the importance of not just limiting new carbon emissions but also removing existing atmospheric carbon dioxide is becoming paramount.
Conventional carbon capture methods predominantly target carbon dioxide at its emission sources during carbon-intensive activities. In contrast, DAC aims to remove carbon dioxide from the broader atmospheric conditions. This becomes increasingly important as reliance on fossil fuels diminishes, thereby reducing the need for source-specific carbon capture.
The groundbreaking research from Northwestern University explores a fresh approach for capturing carbon from the ambient environment. It relies on the interactions between water and carbon dioxide to inform the “moisture-swing” technique, incorporating advanced kinetic models and a variety of ions that allow for carbon extraction from nearly any location.
The findings were recently disseminated in the scientific journal, Environmental Science and Technology.
Vinayak P. Dravid, a senior author of the study and the Abraham Harris Professor of Materials Science and Engineering at Northwestern’s McCormick School of Engineering, stated, “Our work not only expands and refines the ion selection for carbon capture but also sheds light on the basic principles of fluid-surface interactions, thereby contributing to a greater collective understanding of DAC.”
Co-first authors of the paper, Ph.D. students John Hegarty and Benjamin Shindel, noted the environmentally-responsive nature of moisture-swing carbon capture as a key advantage. Shindel commented that the process has an undefined energy cost because it ideally relies on naturally occurring dry and wet air reservoirs to drive the reaction.
The research group has also broadened the variety of ions capable of enabling the reaction. “We have not only doubled the number of ions exhibiting the desired humidity-dependent carbon capture properties, but we’ve also identified the most effective systems to date,” added John Hegarty.
Conventional carbon capture techniques often necessitate substantial energy inputs to release captured CO2 for reuse. The moisture-swing technique, however, represents a less energy-intensive alternative.
The research also highlighted that traditional methods are not universally applicable. Industries such as agriculture, concrete, and steel production are major emission sources but present logistical challenges for source-specific carbon capture.
The research was funded by the Department of Energy (DOE-BES DE-SC0022332) and utilized the SHyNE Resource facilities, which are supported by the NSF-NNCI Program (NSF ECCS-2025633).
The study, titled “Expanding the Library of Ions for Moisture-Swing Carbon Capture,” was published on 3 October 2023 and can be accessed via DOI: 10.1021/acs.est.3c02543.
Frequently Asked Questions (FAQs) about moisture-swing method for direct air carbon capture
What is the “moisture-swing” technique in direct air carbon capture?
The “moisture-swing” technique is an innovative method developed by researchers at Northwestern University for capturing carbon dioxide directly from the air. It operates by capturing CO2 at low humidity levels and releasing it at higher humidity levels. The approach utilizes various ions and is considered more energy-efficient compared to traditional carbon capture methods.
Who conducted the research on this new carbon capture method?
The research was conducted by a team at Northwestern University, led by senior author Vinayak P. Dravid, who is the Abraham Harris Professor of Materials Science and Engineering at Northwestern’s McCormick School of Engineering.
Where was the research published?
The findings were disseminated in the scientific journal Environmental Science and Technology.
How does this new method differ from traditional carbon capture techniques?
Traditional carbon capture methods primarily focus on capturing CO2 at the point of emission during carbon-intensive activities. In contrast, the “moisture-swing” technique aims to remove carbon dioxide from broader atmospheric conditions. It is also more energy-efficient, as it uses naturally occurring variations in humidity to drive the carbon capture and release process.
Why is this research important in the context of climate change?
As global efforts shift towards reducing industrial carbon emissions, it becomes crucial to not only limit new emissions but also remove existing atmospheric CO2. The “moisture-swing” technique provides a potentially more energy-efficient and versatile means of capturing carbon from virtually any location, contributing to the broader fight against climate change.
What ions are used in the moisture-swing technique?
The researchers explored a variety of ions, ultimately finding that ions with the highest valency—mostly phosphates—were most effective for this application. The team also discovered new ions that work for this purpose, including silicate and borate.
Is this method commercially viable?
While the article does not explicitly state the commercial viability of the moisture-swing method, it notes that there are companies already working to commercialize direct air carbon capture. Given its energy-efficient nature, the moisture-swing technique may offer a competitive advantage.
Who funded the research?
The research was financially supported by the Department of Energy (DOE-BES DE-SC0022332) and utilized the SHyNE Resource facilities, backed by the NSF-NNCI Program (NSF ECCS-2025633).
More about moisture-swing method for direct air carbon capture
- Environmental Science and Technology Journal
- Northwestern University’s McCormick School of Engineering
- Department of Energy (DOE)
- NSF-NNCI Program
- International Institute for Nanotechnology at Northwestern University
- Climate Change and Carbon Capture Research
- Direct Air Carbon Capture Explained
- SHyNE Resource Facilities