Even as the world gradually begins to decarbonize industrial processes, achieving a reduction in atmospheric carbon concentration requires not just preventing the production of carbon dioxide, but also removing existing carbon dioxide from the atmosphere. Removal techniques are required.
Common carbon capture captures carbon dioxide2 Sourced directly from carbon-intensive process sources. Environmental carbon capture, or “direct atmospheric capture” (DAC), on the other hand, can extract carbon from typical environmental conditions and is an important tool in the fight against climate change, especially as dependence on fossil fuels begins to decline. It acts as one weapon. , the need for carbon capture at the carbon source.
New research from Northwestern University presents a new approach to capturing carbon from ambient environmental conditions that examines the relationship between water and carbon dioxide in the system and informs “moisture swing” techniques to capture CO.2 It releases in low humidity and releases in high humidity. This approach incorporates innovative kinetic techniques and a wide variety of ions to remove carbon from virtually anywhere.
The study was published today (October 3) in the journal environmental science and technology.
“We not only expand and optimize the selection of ions for carbon capture, but also contribute to elucidating the fundamental basis of complex fluid-surface interactions,” said the study’s senior author. said author Vinayak P. Dravid of Northwestern University. “This work advances our collective understanding of DAC, and our data and analysis are powerful tools for theorists and experimentalists alike to further improve carbon capture under real-world conditions. We will provide the community with a positive driving force.”
Dravid is the Abraham Harris Professor of Materials Science and Engineering at Northwestern University’s McCormick School of Engineering and director of global initiatives at the International Nanotechnology Institute. PhD students John Hegarty and Benjamin Schindel were co-lead authors on the paper.
Schindel said the idea behind the paper came from a desire to exploit ambient environmental conditions to promote reactions.
“We liked carbon capture through moisture fluctuations because the energy costs are not defined,” Schindel said. “Humidifying large volumes of air requires some energy, but ideally, relying on an environment with natural dry air stores and humid air stores in close proximity would be energy efficient. You can get humidity for free.
The group also expanded the number of ions used to enable the reaction.
“Not only have we doubled the number of ions that exhibit the desired humidity-dependent carbon capture, but we have also discovered the best-performing system to date,” said John Hegarty.
In recent years, moisture swing capture has attracted attention.Traditional carbon capture methods use adsorbents to capture carbon dioxide2 Release the CO using heat or generated vacuum at the source location2 From adsorbents. High energy costs.
“Traditional carbon capture retains carbon dioxide2 This means it takes a lot of energy to free it up and reuse it,” Mr Hegarty said.
It also doesn’t work everywhere, Schindel said. For example, agriculture, concrete, and steel manufacturers are major contributors to emissions, but their carbon footprint is large, making it impossible to capture carbon at a single source.
Schindel added that while developing countries, which are more dependent on carbon economies, reduce their emissions, rich countries should strive to bring their emissions below zero.2 production.
Another senior author, chemistry professor Omar Farha, has experience studying the role of metal oxide framework (MOF) structures in a variety of applications involving CO.2 Capture and isolation.
“DAC is a complex and multifaceted issue that requires a multidisciplinary approach,” Farha said. “What I appreciate about this work is the detailed and careful measurement of complex parameters. Any proposed mechanism must explain these complex observations.”
Researchers have previously focused on carbonate and phosphate ions to help capture moisture fluctuations, and have developed specific hypotheses about why these particular ions are effective. But Dravid’s team wanted to test a wider range of ions to see which were most effective. Overall, they found that the most highly charged ions (mainly phosphates) were the most effective, and they began going through the list of multivalent ions to exclude some, as well as silicates and borates. We found new ions, such as salts, that are suitable for this application.
The research team believes that a combination of future experiments and computational modeling will better explain why certain ions are more effective than others.
There are already companies working to commercialize direct capture of atmospheric carbon, using carbon credits to incentivize companies to offset their emissions. Many companies capture carbon that would already be captured through activities such as modified agricultural practices, but this approach clearly sequesters CO.2 It can be harvested directly from the atmosphere, where it can be concentrated and ultimately stored or reused.
Dravid’s team plans to integrate such CO2 Capture materials with an early porous sponge platform developed to remove environmental toxins such as oil, phosphates, and microplastics.
Research on direct capture of atmospheric carbon dioxide was supported by the Department of Energy (DOE-BES DE-SC0022332) and utilized the SHyNE resource facility with support from the NSF-NNCI program (NSF ECCS-2025633).
