Photocatalytic degradation of pentachlorophenol by activated carbon-supported zno

Abstract

Activated carbon (AC) was used to support zinc oxide to develop AC/ZnO system. ZnO was used as a photocatalyst to impregnate the carbonaceous material. The samples studied (AC, ZnO and AC/ZnO) were characterized by measuring iodine number, Methylene blue number, scanning electron micros-copy, X-ray diffraction and FTIR spectroscopy. Equilibrium adsorption studies of pentachlorophenol (PCP) from aqueous solutions by the samples studied showed that the experimental data were well adapted to Langmuir and Freundlich models. Degradation kinetics of PCP was well described by the pseudo-first-order model of Langmuir–Hinshelwood. Photocatalytic activity of ZnO and the hybrid system AC/ZnO was evaluated by degradation of PCP in aqueous solution. A synergistic effect of AC and ZnO was observed where a complete photodegradation of PCP was reached within 90 min by AC/ZnO and about 65% using ZnO alone. Degradation of PCP was followed up by monitoring COD. The PCP molecules were adsorbed by the AC hybrid and then efficiently degraded by the ZnO parti-cles supported on AC.