Indoor carbon dioxide capture technologies: a review

Global warming could be slowed down by removing carbon dioxide from the atmosphere, yet classical methods for carbon dioxide capture are fewly adapted to indoor settings with carbon dioxide concentrations of 1000–2000 ppmv. Here we review advanced indoor carbon dioxide capture technology with focus on physical adsorption, chemical adsorption, and materials for carbon capture. Physical adsorption includes thermal swing adsorption, ion exchange, and activated carbon impregnation. Chemical adsorption comprises wet impregnation, chemical grafting, the sol–gel method, electric mixing, the solvothermal method, and phase inversion. We observed that thermal swing adsorption is efficient, requires low energy, and is long-lasting. Wet impregnation fosters the development of high-performance materials with exceptional adsorption capacity through modifications in loading mass fraction and functionalization. Silicon dioxide is the most prevalent support material for wet impregnation, with tetraethylenepentamine and polyethyleneimine loading on silica exhibiting remarkable adsorption capacities, up to 4.05 mmol/g. Coupling of ventilation systems with indoor capture devices is promising for applications. The current research on indoor capture primarily focuses on the enhancement of adsorption capacity, thus often overlooking material stability and adsorption rates. Therefore, mathematical models are needed to optimize cyclic stability.