ABSTRACT This research successfully synthesized a series of porous carbon materials with high efficiency for CO 2 capture based on orange peel resources, and achieved enrichment of nitrogen elements through surface modification. The effects of alkali‐to‐carbon ratio, activation temperature, and urea impregnation concentration on the pore structure of the porous carbon and its adsorption performance under low‐concentration CO 2 conditions were systematically investigated. The structural and surface properties of the materials were analyzed in depth using various characterization techniques, including nitrogen adsorption–desorption isotherms, SEM, TEM, XRD, XPS, and FT‐IR. The results show that when the mass ratio of KOH to precursor carbon is 1:2, the activation temperature is controlled at 700°C, and the urea impregnation concentration is 15wt%, the prepared sample PAC‐2‐15‐700 exhibits excellent pore structure characteristics, with specific surface area ( S BET ), total pore volume, and micropore volume reaching 487 m 2 /g, 0.215 cm 3 /g, and 0.160 cm 3 /g, respectively. The material features hierarchical pores mainly composed of micropores, and the high nitrogen content and functional groups synergistically enhance its performance. Under 273 and 298 K, the CO 2 adsorption capacities reach 4.18 mmol/g and 2.49 mmol/g, respectively. The adsorption behavior conforms to the Freundlich model, with an average adsorption enthalpy of approximately 21.7 kJ/mol. The material shows a significant selectivity for CO 2 over N 2 , with a selectivity coefficient of 6.24, demonstrating its outstanding potential for CO 2 capture.
Zhang et al. (Sun,) studied this question.