Textural Characterization of Activated Carbons Prepared from Oil-palm Stones Pre-treated with Various Impregnating Agents

Activated carbons with relatively high densities and well-developed porosities were prepared from oil-palm stones which were pre-treated with different types of impregnating agents (ZnCl2, H3PO4 or KOH). The benefits derived from impregnation in terms of higher BET surface areas were generally in the following order: 20% ZnCl2 > 40% H3PO4 > 10% KOH. The textural properties such as density and total porosity, overall yield, BET and micropore surface areas and pore size distributions of the activated carbon were related to the concentration of the impregnating solution and the activation conditions (activation temperature and hold time). For the highest BET surface area obtained in this study, the optimum conditions for CO2 activation were found to be at an activation temperature of 750°C for 1 hour from oil-palm stones pre-treated with 20% ZnCl2 for 24 hours. Pore size distribution suggests the application of oil-palm-stone activated carbons as gas-phase adsorbents for air pollution control.