Abstract
Separation of CO(2)/CH(4)/N(2) is significantly important from the view of environmental protection and energy utilization. In this work, we reported nitrogen (N)-doped porous carbon spheres prepared from sustainable biomass glucose via hydrothermal carbonization, CO(2) activation, and urea treatment. The optimal carbon sample exhibited a high CO(2) and CH(4) capacity, as well as a low N(2) uptake, under ambient conditions. The excellent selectivities toward CO(2)/N(2), CO(2)/CH(4), and CH(4)/N(2) binary mixtures were predicted by ideal adsorbed solution theory (IAST) via correlating pure component adsorption isotherms with the Langmuir-Freundlich model. At 25 °C and 1 bar, the adsorption capacities for CO(2) and CH(4) were 3.03 and 1.3 mmol g(-1), respectively, and the IAST predicated selectivities for CO(2)/N(2) (15/85), CO(2)/CH(4) (10/90), and CH(4)/N(2) (30/70) reached 16.48, 7.49, and 3.76, respectively. These results should be attributed to the synergistic effect between suitable microporous structure and desirable N content. This report introduces a simple pathway to obtain N-doped porous carbon spheres to meet the flue gas and energy gas adsorptive separation requirements.