Porous activated carbons derived from waste sugarcane bagasse for CO2 adsorption

Business cost concern of solid CO2 adsorbents has motivated the production of porous activated carbons from waste biomass materials. In this work, porous activated carbons were prepared from sugarcane bagasse using different activating agents (air, CO2, H3PO4 and NaOH). Chemically activated porous carbons exhibited better physicochemical properties as compared to the physically activated carbons. Particularly, NaOH-activated carbon (CAC-S) featured a high specific surface area (1149 m2/g) and a large pore volume (1.73 cm3/g). X-ray photoelectron spectroscopy (XPS) analysis confirmed that the CAC-S adsorbent exhibited enhanced total basicity. The desired CAC-S adsorbent showed superior isothermal CO2 uptakes of 5.50 and 4.28 mmol CO2/g at 0 °C and 25 °C and 1 bar. The isosteric heat of adsorption was predicted as 43.96 kJ/mol from the Clausius-Clapeyron equation and Toth model, which indicated intensified interaction between CO2 molecules and the basic carbon surface. The excellent CO2 adsorption performance should be associated with the improved textural properties and enriched surface basicity benefited from NaOH activation. Overall, CAC-S is considered as a promising adsorbent for CO2 adsorption. The recycling of sugarcane bagasse as solid CO2 adsorbents presents environmental implications with respect to waste management and pollutants mitigation.