Takeaways

• Scientists have developed a new air filter that captures CO2 directly from building ventilation systems, offering a low-cost alternative to large carbon-capture plants.
• The filter uses carbon nanofibers and sunlight to trap and release carbon efficiently, achieving up to 92% carbon removal efficiency.
• Researchers say widespread adoption could remove up to 596 million tons of CO2 globally each year.

As carbon emissions continue to rise, researchers are racing to find affordable ways to reverse their impact. Now, scientists have created a groundbreaking air filter that passively captures carbon dioxide (CO2) from building ventilation systems, essentially turning homes, offices, and factories into mini carbon-capture machines.

This new technology could reshape how the world approaches carbon removal, offering a distributed, low-cost alternative to traditional direct-air-capture (DAC) plants, which are often large, expensive, and energy-hungry.

For years, the idea of removing CO2 from the atmosphere has divided climate experts. Activists feared it might slow efforts to cut emissions at the source. But as global reduction efforts lag, even the Intergovernmental Panel on Climate Change (IPCC) acknowledges that carbon capture will play a crucial role in limiting global warming.

Read More: Relying on Natural Carbon Sinks Won't Cut CO2 Emissions

Traditional DAC plants use powerful fans and chemical sorbents to extract CO2 from the air. However, the process requires vast land, costly materials, and high energy input, particularly for heating the sorbents to release captured carbon. This limits where such plants can be built and raises questions about scalability.

The new approach, described in Science Advances, sidesteps these barriers by embedding CO2-absorbing filters directly into heating, ventilation, and air-conditioning (HVAC) systems. These lightweight filters are made of carbon nanofibers coated with polyethylenimine (PEI), a polymer that binds CO2 molecules. Unlike large-scale plants, the filters operate passively as air circulates through existing ducts.

What makes the innovation stand out is its energy efficiency. The nanofibers absorb sunlight so effectively that captured CO2 can be released by gently warming the filter to just 80°C under direct sunlight. Alternatively, a short electric pulse lasting one or two seconds can regenerate the material almost instantly, both methods requiring far less power than conventional carbon-capture systems.

Importantly, these filters cause minimal disruption to airflow, allowing them to be retrofitted into existing buildings without major design changes or added energy use.

According to researchers, the filters can achieve a net carbon removal efficiency of about 92% when regenerated using solar heat. Each kilogram of CO2 removed would generate only 0.073 kilograms of emissions, far lower than most DAC systems today.

In terms of cost, the system could remove CO2 for $362 per ton using solar regeneration or $821 per ton using electricity. With tax incentives and storage credits, net costs could fall to between $209 and $668 per ton, competitive with the lower range of current DAC technologies.

Also Read: Concrete Buildings in Japan Act As Carbon Sinks: Study

If scaled globally, the scientists estimate the technology could remove up to 596 million tons of CO2 per year. However, they note challenges remain in scaling nanofiber production and managing the collection and regeneration of filters.

Still, by transforming billions of HVAC systems into passive carbon-capture devices, this innovation could mark a major step toward making everyday infrastructure part of the climate solution.

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Source: singularity hub