Title : The role of ZnO/Co3O4 nanocomposite in the photocatalytic degradation of diclofenac present in wastewater
Abstract:
Diclofenac (DCF) is a non-steroidal anti-inflammatory drug (NSAID) frequently administered to treat inflammation and pain associated with different rheumatic and non-rheumatic diseases. DCF is found in many environmental samples such as wastewater, surface and drinking water [1-3]. As this pollutant is hardly degraded using conventional wastewater treatment processes, it was necessary to develop more effective methods of removing DCF from aquatic environments, photocatalysis is a promising and effective technique to remove organic pollutants from water and solve environmental pollution problems.
The aim of this work is to synthesize a ZnO/Co3O4 nanocomposite by co-precipitation method for the efficient removal of DCF by activating PMS under LED irradiation. The physico-chemical properties of the material were obtained by: X-ray diffraction (XRD), N2 adsorption/desorption method, scanning electron microscopy (SEM), X-Ray photoelectron spectrometry (XPS), infrared spectroscopy (ATR-IR) and ultraviolet- visible spectroscopy (UV-Vis DRS).
Under optimal conditions, within 60 min of reaction approximatively 80% removal were obtained using 20 mg of catalyst, 0.25 mM of PMS and 30 ppm of DCF under LED irradiation. The results showed that the higher DCF initial concentration was the better the degradation rate was indicating that ZnO/Co3O4- PMS-LED irradiation system is suitable for the degradation of high concentrations of pollutant. Radical quenching experiments were carried out in order to identify different reactive oxygen species (ROS) involved in the degradation of DCF. Based on the results obtained, SO4•- and 1O2 were the main ROS responsible for the degradation of DCF. The results obtained during this study demonstrated that ZnO/Co3O4 nanocomposite has shown encouraging results in the activation of PMS under LED irradiation for the elimination of DCF.
Keywords: ZnO/Co3O4 nanocomposite ; PMS ; Diclofenac ; degradation.
