Nitrogen-enriched hierarchical porous carbon for carbon dioxide adsorption and separation

Abstract

Hierarchical nitrogen-enriched porous carbon containing micropores, mesopores, and macropores were prepared by a nanocasting pathway using a Schiff base precursor and SBA-15 as the hard template. The specific surface area and pore volume of the obtained porous carbon are 752 m2 g–1 and 0.79 cm3 g–1, respectively. The nitrogen content is as high as 7.85% (w). The porous carbon shows a CO2 capacity of 97 cm3 g–1 at ambient pressure and 273 K. The CO2/N2 and CO2/CH4 separation ratios (molar ratios) are accordingly 7.0 and 3.2, and the Henry’s low pressure selectivities are 23.3 and 4.2, respectively. CO2 adsorption tests confirmed that the micropores play a dominant role and nitrogen-containing functional groups play a synergistic role. The predicted ideal adsorbed solution theory (IAST) selectivities of the two-component mixed stream are 40 (CO2/N2) and 18 (CO2/CH4) by Toth mode simulation.