CO2 and CH4 Adsorption Behavior of Biomass-Based Activated Carbons

The aim of the present work is to study the effect of different activation methods for the production of a biomass-based activated carbon on the CO2 and CH4 adsorption. The influence of the activation method on the adsorption uptake was studied using three activated carbons obtained by different activation methods (H3PO4 chemical activation and H2O and CO2 physical activation) of olive stones. Methane and carbon dioxide pure gas adsorption experiments were carried out at two working temperatures (303.15 and 323.15 K). The influence of the activation method on the adsorption uptake was studied in terms of both textural properties and surface chemistry. For the three adsorbents, the CO2 adsorption was more important than that of CH4. The chemically-activated carbon presented a higher specific surface area and micropore volume, which led to a higher adsorption capacity of both CO2 and CH4. For methane adsorption, the presence of mesopores facilitated the diffusion of the gas molecules into the micropores. In the case of carbon dioxide adsorption, the presence of more oxygen groups on the water vapor-activated carbon enhanced its adsorption capacity.