Carbon Dioxide Sorbent from Construction and Textile Plastic Waste

Abstract Plastic waste (PW) from textile and construction industries is rarely recycled due to the lack of economical and effective commercial recycling technologies. In this work, PW from these two sources is successfully converted into a microporous sorbent that is highly selective to carbon dioxide (CO₂) adsorption. The synthesis of the sorbent is achieved by the pyrolysis of PW in the presence of a potassium salt activator. The properties of the sorbent can be tuned by changing the parent plastic type to get varying degrees of microporosity, surface area, and nitrogen content. The best performer, a sorbent derived from nylon 6,12, had a CO₂ uptake of 19 wt% (4.32 mmol g⁻¹) and 5 wt% (1.1 mmol g⁻¹) at 1 and 0.1 bar, respectively. The initial estimated cost of synthesizing the sorbent is ≈$531 tonne⁻¹ of PW making this process economically attractive compared to competitive technologies. The sorbent effectiveness in CO₂ separation is demonstrated from various feeds including simulated flue gas and direct air capture. Thus, this upcycling approach can help to address two environmental challenges: PW pollution and increased atmospheric CO₂ levels.