Study of the Efficiency of Non-Homogeneous Catalytic Ozonation Process using a Catalyst of Magnetic Nanoparticles of Iron Oxide Doped with Silica and Titanium Dioxide in Removal of Metronidazole from Synthetic Wastewater

Antibiotics are widely used in veterinary and medicine in the last few decades which presence of these compounds has made potential risks for aquatic and terrestrial organisms in the environment. Metronidazole is one of these antibiotics. The purpose of this study was investigation of the efficiency of metronidazole removal from aqueous solutions using a catalytic ozonation process with magnetic nanoparticles of iron oxide doped with silica and titanium dioxide. The sol gel method was used to synthesize Fe3O4@SiO2@TiO2 nanoparticles and its properties were investigated by SEM, XRD and EDX analyzes. The effect of parameters such as pH, catalyst dose, reaction time, contaminant concentration, determining the mineralization and scavenger effect were investigated on the process performance. Changes in metronidazole concentration were determined by HPLC. According to the results of this study, pH =10 and catalyst dose of 3 g /l were obtained as optimum conditions and the removal efficiency increased with increasing of contact time and decreasing in the concentration of metronidazole. Results showed that the removal of metronidazole followed first degree model by this process. Rate of TOC was 86% under optimal operating conditions. Catalytic ozonation process with magnetic nanoparticles of iron oxide doped with silica and titanium dioxide can significantly remove metronidazole and it is an appropriate method for removal of metronidazole.