Northwestern University has developed a “moisture-swing” technique for direct air carbon capture which captures CO2 at low humidities and releases it at high humidities, utilizing a range of ions. This research enhances DAC understanding and offers a more energy-efficient carbon capture method compared to traditional techniques.
While traditional carbon capture focuses on collecting CO2 right from its emission point in carbon-heavy processes, “direct air capture” deals with extracting carbon from general atmospheric conditions. This method becomes increasingly significant in the fight against climate change, especially as our dependence on fossil fuels wanes, diminishing the necessity for capturing carbon right at its source.
“We liked moisture-swing carbon capture because it doesn’t have a defined energy cost,” Shindel said. “Even though there’s some amount of energy required to humidify a volume of air, ideally you could get humidity ‘for free,’ energetically, by relying on an environment that has natural dry and wet reservoirs of air close together.”The group also expanded the number of ions used to make the reaction possible.
“Traditional carbon capture holds onto CO2 tightly, which means it takes significant energy to release it and reuse it,” Hegarty said. Another senior author, chemistry professor Omar Farha, has experience exploring the role of metal-oxide framework structures for diverse applications, including CO2 capture and sequestration.