Influence of Zinc Oxide Nanoparticles on the Efficiency of Oxytetracycline Removal from Wastewater Using Continuous Catalytic Ozonation

Abstract

Antibiotics must be fully eliminated before they are released into the environment. In most cases, conventional wastewater treatment systems are not built to handle polar microcontaminants such as antibiotics. Oxytetracycline (OTC) is one of these antibiotics, an environmental hazard contaminant in aqueous solutions. Therefore, an advanced treatment method is needed for wastewater contaminated with antibiotics. In this study, we employed zinc oxide nanoparticles (ZnO), and the catalytic ozonation procedure was employed to increase the ozonation efficiency. A continuous experiment was carried out to compare the effectiveness of catalytic and single ozonation in degrading OTC in a continuous reactor. The flow rate of OTC solution, the initial concentration of OTC, the ozone generation rate, and the bed height of the catalyst were investigated. The highest removal was obtained at a low flow rate of OTC solution (3.9 cm3/s) and with a bed height of 1cm. The first-order model and the rate of the oxidation process were well-matched. The self-decomposition rate constant was found to increase from 0.08 to 0.216 s-1 with increasing pH range (e.g., 3-11 pH). The calculated volumetric mass transfer coefficient of ozone in water increased with pH. Gas Chromatography-mass spectrometry analysis indicated that that oleyl alcohol and oleic acid were the byproducts of this process.