A carbon nanofiber direct air capture filter is described in a paper in Science Advances by researchers in the lab of Assistant Professor Po‑Chun Hsu at the University of Chicago Pritzker School of Molecular Engineering. First author Ronghui Wu, now an assistant professor at Nanyang Technological University, was a postdoctoral researcher in Hsu’s lab during the work.
A life-cycle analysis showed the filter is more than 92% efficient at removing CO2 after accounting for emissions from manufacture, transport, maintenance and disposal. The team designed the polyethylenimine material so the filter removes more CO2 than the amount added across its life. Researchers used experiments and computer models to test the idea of retrofitting buildings as part of wider decarbonization efforts.
The authors estimate that replacing every building air filter with this model could remove up to 596 megatonnes of CO2, equivalent to taking 130 million cars off the road for a year. A 2024 study indicated individual energy savings of up to about 21.6%. The filters fit existing HVAC systems like HEPA filters and are regenerated rather than discarded. Saturated household and commercial filters would be collected and sent to central facilities to dissolve or concentrate CO2 for storage or conversion. The material’s high solar absorptivity allows solar thermal release, but regeneration must use renewable energy.
Lower indoor CO2 can also improve air quality in classrooms and offices and help people stay more alert and healthy.
Difficult words
- nanofiber — Very thin fibres at microscopic scale
- direct air capture — Process that captures carbon dioxide from air
- life-cycle analysis — Study of environmental impact across a product
- polyethylenimine — A chemical used to capture carbon dioxide
- retrofit — To add new technology to old buildingsretrofitting
- decarbonization — Process of reducing carbon emissions in systems
- megatonne — One million tonnes used to measure emissionsmegatonnes
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Discussion questions
- Would it be practical to replace every building air filter with this model in your city? Why or why not?
- How could lower indoor CO2 from these filters affect people at work or school?
- What challenges might exist for collecting saturated filters and sending them to central facilities?
