An economical-friendly biomass-based porous carbon with chitosan modification for the favorable adsorption of CO2 and toluene

Nitrogen-doped biomass-based porous carbon as a desirable solid adsorbent has been studied on CO2 and VOCs adsorption from the perspective of a single-component gas frequently. However, whether the same nitrogen-containing porous carbon could facilitate the adsorption performance of both CO2 and VOCs was rarely confirmed. Herein, a series of N-doped porous carbons with developed pore structures were synthesized by chitosan modification and KOH activated from eucalyptus bark. The obtained materials exhibit an excellent CO2 capacity of 4.00 mmol/g (25 ℃) and 5.71 mmol/g (0 ℃) and a great toluene capture of 4.37 mmol/g (25 ℃) as well. Combined with grand canonical Monte Carlo (GCMC) simulation and density functional theory (DFT) calculations, the mechanism of toluene adsorption was supported by calculating the adsorption density and adsorption energy. More importantly, it was discovered the specific nitrogen functional groups that affect the adsorption of CO2 and toluene. It can be expected that pyridinic-N and amino-N play a chief role during the low-pressure CO2 adsorption and toluene adsorption, correspondingly. This work provides a valuable theoretical basis for the preparation of biomass porous carbon with excellent CO2 and VOCs adsorption properties in practical industrial applications.