Nanofiber Filter Turns Building Vents Into Carbon Capture Devices

The filter was specifically designed with excellent solar absorptivity, enabling CO₂ removal through solar-thermal heating. “It has to be able to regenerate using renewable energy,” Hsu said. “The most common way to regenerate CO₂ with solvent is by heating it up. If you burn fossil fuels to heat up the solvent, then you will probably end up emitting more carbon dioxide than you capture.”

This approach contrasts with centralized direct air capture facilities that require massive land use and capital investment. Hsu likens it to solar power—a technology once confined to utility-owned solar farms, but now a network of large farms and small rooftop panels working toward the same energy goal.

Beyond climate benefits, the filter improves indoor air quality. “This kind of air filter can also improve indoor air quality, especially in places like classrooms and offices where many people share the same space,” Wu said. “By keeping indoor carbon dioxide levels low, it helps people stay more alert, focused and healthy.”

This is particularly relevant in cities facing severe air quality challenges. High indoor CO₂ levels impair cognitive function, decision-making and focus—problems common in crowded classrooms and offices.

Hsu and Wu envision an ecosystem where municipal waste management systems collect filters weekly with garbage and recycling. “They would have these saturated filters from household ventilation systems and commercial buildings, then replace them with new ones,” Hsu said. “They’d ship the saturated one to a centralized facility to dissolve the CO₂ or make it into highly concentrated CO₂ to capture or, even better, convert to high-value chemicals or fuel.”

This circular economy model transforms carbon capture from an expense into a resource recovery system. The extracted CO₂ can be converted to fertilizer, dry ice or industrial chemicals, creating revenue streams that offset filter costs.

The research builds on growing efforts to address record CO₂ levels in the atmosphere. Combined with renewable energy expansion and other mitigation strategies, distributed building-based carbon capture could contribute significantly to climate targets.

The development of the carbon nanofiber direct air capture filter by the University of Chicago Pritzker School of Molecular Engineering was detailed in Science Advances. A carbon removal efficiency of 92.1% was reported for the device from cradle to grave. The potential for these filters to be integrated into existing HVAC infrastructure was noted, with estimates suggesting global removal of 596 megatonnes of CO₂ annually upon widespread adoption. Energy savings of up to 21.66% for building operations were projected due to reduced ventilation requirements. A proposed waste management cycle involving centralized collection and solar regeneration of filters was outlined by the researchers.