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 CO2 from flue gas. Optimal adsorption performance can be obtained by specific solid adsorbents with excellent CO2 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 CO2 uptake of 3.37 and 5.23 mmol g(-1) at 1 bar, 25 degrees C and 0 degrees 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/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 CO2 capture. (c) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

This study synthesized N, S co-doped porous carbons with high CO2 uptake, excellent CO2 capture properties, and good recyclability and adsorption kinetics. These results suggest that these porous carbons are potential sorbents for CO2 capture.