Distributed direct air capture by carbon nanofiber air filters.

Wu, Ronghui; Delgado, Hernan E; Xie, Yi; Chen, Yuanke; Yan, Gangbin; Luo, Edward; Li, Qizhang; Fan, Qingsong et al. · Sci Adv · 2025

basic_science · Level V

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Abstract

The rising atmospheric CO<sub>2</sub> concentration is one of the biggest challenges human civilization faces. Direct air capture (DAC) that removes CO<sub>2</sub> from the atmosphere provides great potential in carbon neutralization. However, the massive land use and capital investment of centralized DAC plants and the energy-intensive process of adsorbent regeneration limit its wide employment. We develop a distributed carbon nanofiber (CNF)-based DAC air filter capable of adsorbing CO<sub>2</sub> downstream in ventilation systems. The DAC air filter not only has the potential to remove 596 MtCO<sub>2</sub> year<sup>-1</sup> globally but can also decrease energy consumption in existing building systems. The CNF-based adsorbent has a capacity of 4 mmol/g and can be regenerated via solar thermal or electrothermal methods with low carbon footprints. Through life cycle assessment, the CNF air filter shows a carbon removal efficiency of 92.1% from cradle to grave. Additionally, techno-economic analysis estimates a cost of $209 to 668 in capturing and storing 1 tonne of CO<sub>2</sub> from direct air.