Production of Activated Carbon from Wood Waste by Chemical Activation Technique and Its Application to Industrial Wastewater Treatment

A novel two-step chemical activation technique, consisting of carbonization and phosphoric acid activation in sequence, was investigated for activated carbon production from waste wood pallets in Hong Kong. A widely used commercial activated carbon, Calgon Filtrasorb® 400 (F400), was studied in parallel for comparison. The physical properties and surface chemistry of the activated carbon were determined by proximate and ultimate analyses, BET-N2 adsorption, Boehm’s titration, infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The wood waste-derived activated carbon possessed physical properties (surface area and pore volume) that were comparable to those of F400, but displayed distinctive surface chemistry in terms of pHPZC, surface acidity and basicity, and surface functional groups. The applicability of activated carbon in industrial wastewater treatment was then assessed by means of batch study on methylene blue and phenol removal. In comparison with F400, the wood waste-derived activated carbon showed better removal efficiency for methylene blue removal because of its faster adsorption kinetics, negligible pH-dependence, and high adsorption capacity. Surface chemistry rather than physical properties of activated carbon was found to determine the adsorption mechanism and capacity of contaminants. It is plausible that activated carbon can be tailor-made from a broad range of organic waste materials to achieve distinctive surface chemistry for selective removal of a variety of contaminants (e.g., cationic, anionic, or molecular structure) from industrial wastewater. This study demonstrated that the production of activated carbon from wood waste is a cost-effective clean technology that can enhance sustainable development by saving the waste disposal cost, extending the lifetime of landfill, and providing valuable products (activated carbon) for remediation applications.