Photocatalytic decomposition of metronidazolein aqueous solutions using titanium dioxide nanoparticles

Abstract

The presence of pharmaceuticals drugs in aquatic environment is a growing environmental concern due to their drug-related adverse effects on aquatic ecosystems. In this study the effects of some operational parameters such as pH, concentration of titanium dioxide nanoparticles, exposure time and intensity of UV were evaluated using photo catalytic process by nanoparticles of titanium dioxide (TIO2). The results showed that the removal of metronidazole and COD have a direct connection with the intensity of the UV lamp and exposure time. Metronidazole removal efficiency at each exposure time decreases with increasing pH. Moreover the results showed that at exposure times of 30 and 60 minutes the removal efficiency for COD and metronidazole were reduced by increasing TIO2, but they were increased when exposure time was increased to 180 minutes and TIO2 nanoparticles' concentration increased from 0.5 to 3 g. L-1, which this could be related to the presence of more active sites on the catalyst surface and more impact of UV at higher concentrations. According to obtained results, it can be concluded that the photo catalytic process using TIO2 nanoparticles could be an effective and promising method for treatment of aqueous solutions containing Metronidazole.