Porous and adsorption properties of activated carbon prepared from cocoa pod husk by chemical activation

Utilization of cocoa pod husk (CPH) for the preparation of high-surface-area activated carbon (AC) by using low-pollution potassium hydroxide (KOH) as an activating agent was studied in this work. The thermochemical results of CPH, including the proximate analysis, calorific value, organic and mineral component analyses, showed that the biomass should be a great precursor based on its large percentage of volatile matter and less amount of fixed carbon. A series of activation experiments were conducted to produce activated carbons from dries CPH at different temperatures (i.e., 400, 500, 600, 700, and 800 °C) held for 30 min. To evaluate the potential for adsorbent in removing environmental pollutants, the resulting activated carbons were subject to the analyses of chemical and physical properties, including elemental analysis, true density, surface area/pore volume, and surface morphology by scanning electron microscope (SEM). Based on the pore properties, activation temperature at around 800 °C seemed to be the optimal condition for producing highly microporous AC, where its BET surface area (> 1800 m2/g) and total pore volume (about 0.95 cm3/g) largely increased compared with that of the AC produced at 400 °C (ca. 6.0 m2/g). Based on the adsorption kinetic performance tests, it showed that it is feasible to use the resulting AC as an effectively low-cost adsorbent for the removal of organic compound (e.g., dye) from aqueous solution in comparison with commercial AC.