Nanoporous carbon based palm kernel shell and its characteristics of methane and carbon dioxide adsorption

Abstract

Biogas is typically composed of 55% methane, 45% carbon dioxide, and small amount of impurities. For high quality of fuel, it is necessary to increase percentage of methane by removing carbon dioxide. This can be performed by molecular sieve utilizing different diffusivity of methane and carbon dioxide passing through pores. This work presents a study of adsorption properties (isotherm and kinetics) of carbon dioxide and methane on porous carbon from palm kernel shell. The biochar of palm kernel shell was activated at high temperature of 800 °C with steam. The carbon produced was then characterized by N2-sorption analysis, and ultimate analysis. The usability of material for CO2 and CH4 adsorption was tested using a static volumetric method. The results showed that steam-activated porous carbon features a higher surface area (650 m2 g−1) and more mesoporous structures with respect to the carbon produced without steam activation. In the adsorption study, the results showed that the carbon exhibited a higher adsorption to CO2 (2.0 mmol g−1) than CH4 (1.1 mmol g−1) at 1 atm and 30 °C. In the adsorption kinetics test, results displayed that the adsorption of CO2 on carbon is slower than methane, which is good for separation purposes.