Rinnovabili • CO2 capture filters turn buildings into urban decarbonization tools Rinnovabili • CO2 capture filters turn buildings into urban decarbonization tools

Buildings become emission fighters with new CO2 capture filters

A breakthrough in carbon capture could turn buildings into active allies against climate change. A new generation of CO2 capture filters, designed with carbon nanofibers, can remove up to 92.1% of carbon dioxide directly from the air while consuming minimal energy.

CO2 capture filters turn buildings into urban decarbonization tools

CO2 capture filters in HVAC systems: a new model for direct air capture

A new CO2 capture filter technology is redefining how we remove carbon dioxide from the atmosphere, transforming standard ventilation systems into tools for urban decarbonization. Developed by an international research team, the filter can be installed in existing HVAC (Heating, Ventilation, and Air Conditioning) systems to capture CO2 even at low concentrations.

By integrating CO2 capture filters directly into HVAC systems, the technology enables a distributed approach to direct air capture (DAC). This method lowers costs and overcomes the limitations of centralized DAC plants, which are often large, expensive, and energy-intensive. The filter itself is made of conductive carbon nanofibers coated with polyethyleneimine, a compound that selectively absorbs CO2 while allowing other air components to pass freely.

Low energy use and easy regeneration

One of the main advantages of this innovation is its ease of regeneration. Unlike conventional DAC technologies, the filter can be reactivated with low amounts of energy, using either solar heat or low-voltage electricity. This feature allows continuous operation over time while maintaining a net CO2 removal efficiency of 92.1%.
Operational costs range between $209 and $668 per ton of CO2 captured, making the system competitive with large-scale carbon removal solutions.

CO2 capture filters
Concept and advantages of DAC air filter using CNF-based adsorbents. Credit: Science Advances, 2025. DOI: 10.1126/sciadv.adv6846 – Creative Commons Attribution Non Commercial 4.0 License

Global potential and future applications

Researchers estimate that if CO2 capture filters were integrated into existing ventilation systems worldwide, they could remove about 596 million tons of CO2 annually, roughly 2% of global emissions.
This distributed approach leverages existing infrastructure, avoiding the need for costly new facilities. The next step is to scale production and incorporate the filters into sustainable building projects.

The study, “Distributed direct air capture by carbon nanofiber air filters,” was published in Science Advances.

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About Author / Alessia Bardi

Alessia Bardi is Rinnovabili's General Manager and Head of the Green Building and Smart City sections at Rinnovabili, where she develops editorial content and in-depth features on key topics such as energy efficiency, urban innovation, and climate transition. She also manages content strategy for industry events, overseeing their organization with a focus on emerging technologies applied to sustainable construction, smart cities, and the energy transition. Trained as an architect and a graduate of the Politecnico di Milano, she has worked with international firms on sustainable design, urban planning, tourism development, and hospital infrastructure projects. Passionate about design thinking and cross-disciplinary approaches, she has also contributed to the creation of a line of 3D-printed jewelry. She firmly believes in the crucial role of technical information and tech-driven innovation in accelerating the adoption of smart, scalable solutions in the energy and environmental sectors.