A detailed study of pyrolysis conditions on the production of steam-activated carbon derived from oil-palm shell and its application in phenol adsorption

Oil-palm shell, a biomass waste from the palm oil industry, can be converted into commercially viable activated carbon through pyrolysis, followed by activation. A detailed systematic study of the pyrolysis conditions and initial shell particle size was conducted, and they were found to have significant effects on the pore characteristics of steam-activated carbons. The optimum pyrolysis conditions were (i) pyrolysis temperature of 750 degrees C, hold time of 2 h, heating rate of 10 degrees C/min, nitrogen flow rate of 150 cm(3)/min and particle size range of 2-2.8 mm for pyrolysis in nitrogen flow, and (ii) pyrolysis temperature of 675 degrees C, hold time of 2 h, heating rate of 10 degrees C/min and particle size range of 2-2.8 mm for pyrolysis under vacuum. Under nitrogen pyrolysis environment, the best activated carbon yielded the highest BET surface area of 794 m(2)/g and achieved the largest adsorption capacity of 129 mg of phenol per g of activated carbon. Under vacuum pyrolysis, the best activated carbon yielded the highest BET surface area of 988 m(2)/g and achieved the largest adsorption capacity of 168 mg of phenol per g of activated carbon which was respectively 24% and 30% greater than those for the activated carbon pyrolysed in nitrogen flow. Of all pyrolysis parameters studied-pyrolysis temperature, hold time, heating rate (low heating rate region), nitrogen flow rate, shell particle size and pyrolysis environment-the pore characteristics of the steam-activated carbons are strongly dependent on the pyrolysis temperature, hold time, pyrolysis environment and initial particle size.