Plastic Waste Product Captures Carbon Dioxide in Nanometer Pores

Plastic waste (PW) and increasing atmospheric carbon dioxide (CO₂) levels are among the top environmental concerns presently facing humankind. With an ambitious 2050 zero-CO₂ emissions goal, there is a demand for economical CO₂ capture routes. Here we show that the thermal treatment of PW in the presence of potassium acetate yields an effective carbon sorbent with pores width of 0.7-1.4 nm for CO₂ capture. The PW to carbon sorbent process works with single or mixed streams of polyolefin plastics. The CO₂ capacity of the sorbent at 25 °C is 17.0 ± 1.1 wt % (3.80 ± 0.25 mmol g^-1) at 1 bar and 5.0 ± 0.6 wt % (1.13 ± 0.13 mmol g^-1) at 0.15 bar, and it regenerates upon reaching 75 ± 5 °C. The CO₂ capture cost from flue gas via this technology is estimated to be <$21 ton^-1 CO₂, much lower than competing CO₂ capture technologies. Hence, this PW-derived carbon material should find utility in the capture of CO₂ from point sources of high CO₂ emissions while providing a use for otherwise deleterious PW.