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

Abstract

BackgroundsAdsorption by adsorbents is accepted as a promising technology that can efficiently separate CO2 from flue gas. Optimal adsorption performance can be obtained by specific solid adsorbents with excellent CO2 adsorption capacity. MethodsIn 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 findingsThis series of sorbents has the highest CO2 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 CO2 uptake of these adsorbents. Additionally, these adsorbents also show various good CO2 capture properties such as excellent recyclability, reasonable CO2/N2 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 CO2 capture.