Effect of heat treatment temperature on CO2 capture of nitrogen-enriched porous carbon fibers

Porous carbon fibers (PCFs) were prepared from porous polyacrylonitrile fibers by cross-linking, oxidation, and carbonization. X-ray diffraction patterns revealed that graphite structures as well as disordered carbon coexisted in the PCFs. Nitrogen content was more than 15.3 wt% with the variation of oxidation temperature, and a maximum value was obtained at 275°C. Nitrogen was quickly released with carbonization temperature. Compared with the fiber prepared at elevated carbonization temperatures, those owning high nitrogen contents deserved better carbon dioxide (CO 2 ) adsorption performance in the simulated flue gas environment (10% CO 2 /90% N 2 ). The CO 2 adsorption had a better relationship with nitrogen content rather than specific surface area and pore volumes. Especially, nitrogen was very useful to enhance the CO 2 adsorption of the fibers with low microporosity. The heat of CO 2 adsorption was in the range of 39.8–54.6 kJ mol −1 , which indicated good selectivity of CO 2 adsorption. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.