Sustainable microcrystalline cellulose-based activated carbons for a greener carbon capture at post-combustion conditions

Using lignocellulosic biomass-based sorbents for CO2 capture potentially offers a sustainable solution to combatting global warming effects and preserving the environment through reduction of greenhouse gas emissions, mainly carbon dioxide. In this work, activated carbons were produced from microcrystalline cellulose using a simple, moderate physical activation procedure. Activations produced at 10, 20 and 30% burn-off along with the original biochar were characterised for their physical and chemical properties, and ability to capture CO2 by adsorption. CO2 isotherms showed that the produced activated carbon with a burn-off of 30 wt% produced the highest CO2 adsorption capacity (2.15 mmol/g at 25 degrees C and 101.3 kPa). Isosteric heats of adsorption of all sorbents ranged from 38.4 to 45.2 kJ/mol, which indicates that strong bonding is present on the surface of the developed sorbents. The highest CO2 adsorption capacity (1.59 mmol/g at 25 degrees C and 101.3 kPa) under dynamic adsorption conditions at was also exhibited by the sorbent with 30 wt% burn-off. This sample also showed a total CO2 adsorption capacity of 15.8 mmol/g over 10 adsorption/desorption cycles and similar adsorption-desorption behaviour to that of commercial sorbent Norit R2030CO2 over 10 cycles, at the conditions tested. Additionally, all sorbents maintained a stable CO2 capture capacity over 10 adsorption-desorption cycles. The results obtained are encouraging for the further development of microcrystalline cellulose-based activated carbons for CO2 capture.