Nitrogen and sulfur co-doped porous carbons from polyacrylonitrile fibers for CO2 adsorption

Backgrounds Adsorption by adsorbents is accepted as a promising technology that can efficiently separate CO 2 from flue gas. Optimal adsorption performance can be obtained by specific solid adsorbents with excellent CO 2 adsorption capacity. Methods In this work, N, S co-doped porous carbons were synthesized from polyacrylonitrile fiber by a facile synthesis process i.e. hydrothermal treatment followed by KOH activation. N, S enriched hydrochar was obtained after hydrothermal treatment of polyacrylonitrile fiber and ammonium sulfide. Further KOH activation of hydrochar obtained N, S co-doped carbons with advanced porous structure. Significant findings This series of sorbents has the highest CO 2 uptake of 3.37 and 5.23 mmol g −1 at 1 bar, 25 °C and 0 °C, respectively. Detailed investigation revealed that the mutual effects of narrow microporostiy, N and S content are responsible for the CO 2 uptake of these adsorbents. Additionally, these adsorbents also show various good CO 2 capture properties such as excellent recyclability, reasonable CO 2 /N 2 selectivity, moderate heat of adsorption, fast adsorption kinetics, and good dynamic adsorption capacity. These findings suggest that N, S co-doped porous carbons derived from polyacrylonitrile fiber are potential promising sorbents for CO 2 capture.