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 are produced from microcrystalline cellulose at 10, 20 and 30 wt% burn-offs with these sorbents and the original biochar characterised for their physical properties and ability to capture CO2 by adsorption. CO2 isotherms showed a burn-off of 30% produced the highest CO2 adsorption capacity, 2.15 mmol/g at 25 °C and 1 bar. Isosteric heats of adsorption of all sorbents ranged from 38.43 to 45.23 kJ/mol, which showed that strong bonding is present on the surface of the developed sorbents. The highest CO2 adsorption capacity, 1.59 mmol/g was exhibited by the 30% burn-off sorbent under dynamic adsorption conditions at 25 °C and 1 bar. The sorbent with 30% burn-off also possessed a total capture capacity of 15.82 mmol/g over 10 adsorption/desorption cycles, similar to that of commercial sorbents Norit R (15.78 mmol/g) and higher than that of Zeolite 13X (14.03 mmol/g) over 10 cycles. Additionally, all sorbents maintained a stable CO2 capture capacity over 10 adsorption-desorption cycles. The results obtained from characterisations are encouraging for the further development of microcrystalline cellulose-based activated carbons for CO2 capture.