Researchers from Northwestern University have made strides in carbon capture technology, demonstrating that numerous readily available materials can facilitate the capture of CO2 directly from the atmosphere. The research, published in the journal Environmental Science & Technology, identifies materials like aluminum oxide and activated carbon as promising candidates in moisture-swing direct air capture methods. "The study introduces and compares novel platform nanomaterials for moisture-swing carbon capture, specifically carbonaceous materials like activated carbon, nanostructured graphite, carbon nanotubes and flake graphite, and metal oxide nanoparticles including iron, aluminum, and manganese oxides,” explained John Hegarty, a Ph.D. candidate in materials science and engineering and co-author of the study.
Such advancements in carbon capture technology are pivotal in addressing rising atmospheric CO2 levels, an issue that persists despite global efforts to reduce carbon waste. By developing cost-efficient and scalable solutions, it may become feasible to offset emissions from sectors like agriculture and aviation, where pinpointing and capturing emissions have proven challenging.
Moisture-swing direct air capture, which capitalizes on humidity changes to capture carbon, is highlighted as a promising approach. Traditionally reliant on ion exchange resins, the scalability of these methods has been hindered by cost and energy consumption. However, the Northwestern team believes they can lower these barriers by utilizing sustainable, inexpensive materials often sourced from organic waste or feedstock.
Benjamin Shindel, a Ph.D. graduate from Northwestern, praised the moisture-swing methodology for enabling CO2 sequestration with low energy costs. "The moisture-swing methodology allows for CO2 to be sequestered at low humidity and released at high humidity, reducing or eliminating the energy costs associated with heating a sorbent material so it can be reused,” Shindel stated.
Professor Vinayak P. Dravid, who led the research, emphasized the importance of designing systems that leverage natural gradients, such as day-night cycles, to maximize efficiency without excessive energy demands. Dravid serves as the Abraham Harris Professor of Materials Science and Engineering at Northwestern and holds multiple leadership roles within the university.
The research team—including co-authors Hegarty, Shindel, Michael L. Barsoum, and advisor Omar K. Farha—hopes to inspire further exploration in carbon capture materials. "Carbon capture is still in its nascent stages as a field," Shindel remarked. "The technology is only going to get cheaper and more efficient until it becomes a viable method for meeting emissions reductions goals for the globe."
The paper was supported by the Department of Energy, and its characterizations and measurements were backed by the National Science Foundation’s SCHyNE Resource.