Indoor CO2 direct air capture and utilization: Key strategies towards carbon neutrality

Direct air capture (DAC) is a promising technology that can help to remove carbon dioxide (CO2) from the air. One application of DAC is indoor CO2 direct air capture (iCO2-DAC). A wide range of materials with unique properties for CO2 capture have been investigated, including porous materials, zeolites, and metal-organic frameworks. The selection of suitable materials for iCO2-DAC depends on several factors, such as cost, CO2 adsorption capacity, and stability. The development of new materials with improved properties for iCO2-DAC is an active research area. The captured CO2 can serve as a renewable carbon source to produce biofuels for internal use (e.g., for heating purposes), decreasing the environmental impact of buildings. This review article highlights the importance of iCO2-DAC to improve indoor air quality in buildings and boost the circular economy. We discuss the available carbon capture technologies and materials, discussing their properties and focusing on those potentially applicable to indoor environments. We also provide a hypothetic scenario where CO2 is captured from different indoor environments and transformed into sustainable fuels by using an emerging carbon capture and utilization technology (microbial electrosynthesis). Finally, we evaluate the economic feasibility of such an innovative approach in comparison to the use of traditional, fossil-based fuels.