Oil palm shell, a solid waste of palm oil industry in Malaysia was used as a precursor material for the production of micro- and mesoporous activated carbon. The chemical activation process with different dehydrating agents was impregnated with the oil palm shell and pyrolyzed at various temperatures under the nitrogen and carbon dioxide, respectively. The characteristics of activated carbons were estimated from nitrogen adsorption-desorption at 77 K at the relative pressure range of 0.005-0.99. The activated carbon with highest BET surface area 1367 m2 g-1 were obtained at 500 oC, 1917 m2 g-1 at 700 oC and 2205 m2 g-1 at 800 oC activated by ZnCl2, H3PO4 and KOH, respectively. The t-plot method was used to estimate the micropore and external surface area where the activated carbon that impregnated with ZnCl2 has higher micropore area, while with H3PO4 and KOH have higher external surface area. The carbon prepared by ZnCl2 gave Type I isotherm with predominantly micropores, and this was supported by the pore size diameters results using the Dubinin-Astakhov method. However the carbons prepared by H3PO4 and KOH gave a combination of Type I and IV isotherms with a broad hysteresis loops indicated predominantly mesopores. The Dubinin - Radushkevich method was used to estimate the micropore volume. This shows the activated carbon prepared by KOH to contain the largest micropore volume. The morphology of the activated carbons was observed by SEM, showing that the carbon were full of the cavities.

keywords: activated carbon; chemical activation; micro- and mesopores