Microporous oil-palm-shell activated carbon prepared by physical activation for gas-phase adsorption

Preparation, characterization, and evaluation of activated carbon from oil-palm shell, an abundant agricultural byproduct in some tropical countries, were carried out. The effects of CO2 activation conditions (i.e., activation temperature and hold time) on the characteristics of the activated carbon, namely, composition, porosity, hardness, and internal pore surface area, were investigated in order to optimize preparation parameters. To analyze the reaction kinetics, a random pore model was developed to determine pore development during the carbon-CO2 reaction process. Adsorption tests showed that the activated carbons prepared from oil-palm shells were more suitable for gas-phase rather than liquid-phase applications. When SO2 gas was used as the adsorbate, a linear relationship between the specific pore surface area and the adsorptive capacity of the adsorbent was observed. This could be elucidated by the neutral (or slightly acidic) nature of the surface functional groups, as detected by Fourier transform infrared spectroscopy, on the oil-palm-shell activated carbon.