High yield and high packing density porous carbon for unprecedented CO2 capture from the first attempt at activation of air-carbonized biomass

The first attempt at activation of air-carbonized carbon reveals unusual resistance to activation and unprecedentedly high yields (32-80 wt%) of high packing density (0.7-1.14 g cm(-3)) microporous carbon dominated by 5.5-7 angstrom pores, which are just right for CO2 uptake (up to 5.0 mmol g(-1)) at 1 bar and 25 degrees C. The high gravimetric uptake and packing density offer exceptional volumetric storage, and unprecedented performance for low pressure swing adsorption (PSA) with working capacity of 6-9 mmol g(-1) for a pure CO2 stream (6 to 1 bar) and 3-4 mmol g(-1) for flue gas (1.2 to 0.2 bar). The working capacity for vacuum swing adsorption (VSA) is attractive at 5.0-5.4 mmol g-1 under pure CO2 (1.5 to 0.05 bar), and 1.8-2.2 mmol g(-1) for flue gas (0.3 to 0.01 bar). The pure CO2 volumetric working capacity breaks new ground at 246-309 g l(-1) (PSA) and 179-233 g l(-1) (VSA). For flue gas conditions, the working capacity is 120 to 160 g l(-1) (PSA). The performance of the activated air-carbonized carbons is higher than the best carbons and benchmark zeolites or MOFs.