Preparation and Evaluation of a Coconut Shell-Based Activated Carbon for CO2/CH4 Separation

Biomass is a widely distributed and renewable source of carbon. The main objective of this work is to produce an activated carbon from coconut shells with suitable characteristics to separate CO2 from biogas. The textural characterization of the adsorbent has been determined. Pure component adsorption isotherms of CO2 and CH4 at 30, 50 and 70 °C have been measured. The results reveal that the activated carbon had high CO2 adsorption capacity. Equilibrium of adsorption of CO2 and CH4 adsorption on the produced activated carbon reached 8.36 mmol/g and 4.63 mmol/g, respectively, at 30 °C and 10 bars. Moreover, the performance of the produced activated carbon, as a potential adsorbent for CO2 capture from a CO2/CH4 gas mixture, has been evaluated under dynamic conditions in a dedicated fixed-bed setup. The CO2 and CH4 adsorption capacities of the produced activated carbon are estimated to be 1.86 and 0.52 mol/kg, respectively, at 30 °C and 1 bar.