Indoor CO₂ Direct Air Capture with Self-Assembled Nanofiber Architectures via Electrospinning

The intensifying effects of climate change have underscored the urgency of developing alternative and sustainable technologies to achieve carbon neutrality. Various strategies for carbon dioxide (CO₂) capture, conversion, and the preparation of relevant materials have been addressed through individually-tailored approaches. Hence, there is an urgent need for a flexible process to ensure optimal methods and materials, facilitating a convenient and swiftly implementable approach to reduce CO₂ emissions. In particular, indoor CO₂ direct air capture (iCO₂-DAC) represents a significant application of carbon capture technology. A diverse array of materials possessing distinct properties for CO₂ capture have been explored, such as amine-based adsorbent, carbon based porous materials, zeolites, and metal-organic frameworks, among others.

Therefore, this study aimed to develop polyethylenimine (PEI) and poly-methyl-methacrylate (PMMA) carbon nanofiber as effective CO₂ adsorbents using porous materials fabricated via electrospinning. This self-assembled process was designed to expedite their practical deployment, leveraging adsorption's notable benefits for CO₂ capture, including simplicity of operation, broad applicability, cost-effectiveness, and stable performance in indoor environments where CO₂ concentrations typically range from 1000 to 3000 ppm, occasionally peaking at 6000 ppm.

Utilizing electrospinning and commercially available materials like PEI for CO₂ chemisorption and PMMA as a base for porous carbon nanofibers, a composite self-assembled nanofibrous structure (PEI/PMMA CNFs) can be engineered to achieve excellent CO₂ capture. This is accomplished through straightforward process adjustments, such as manipulating fiber pore size and concentration via the Breath Figures method under varying relative humidity conditions during electrospinning.

This study may provide a reconfigurable manufacture to ensure a reliable adsorbent for CO₂ capture and base materials on those potentially applicable to indoor environments, furthermore, the potential uses of iCO₂-DAC to improve indoor air quality in buildings and boost the circular economy.

This work was supported by a Basic Research Fund (NK249A and NK252H) of the Korea Institute of Machinery and Materials, Republic of Korea, and by the Korea Institute of Marine Science & Technology Promotion (KIMST), funded by the Ministry of Oceans and Fisheries (20220568).