CO₂ Capture with Activated Carbon Grafted by Nitrogenous Functional Groups

Amino/nitro groups were introduced onto the surface of the activated carbon (AC) with nitration followed by reduction in order to improve its adsorption capacity toward CO 2 . These AC samples were characterized by N 2 adsorption/desorption, FTIR, and X-ray photoelectron spectroscopy (XPS). CO 2 adsorption properties of the samples were investigated using a self-regulating high-pressure adsorption apparatus. Results showed that the contents of nitrogen on the treated samples’ surface increased from 0% to 1.38 after modification. The maximum CO 2 adsorption capacity of the modified samples can reach 19.07 mmol/g at 298 K and 36.0 bar. The adsorbed amounts of CO 2 on all samples decreased with an increase in the adsorption temperature, but the extent of the decrease with the modified samples was less than that of the raw AC sample. CO 2 adsorption capacities of the modified sample for five cyclic adsorption–desorption runs were found to be nearly identical.