Removal of Metronidazole from Aqueous Solution Using Ozonation Process

Background and Antibiotics have worldwide uses and they can enter water sources through different ways. Due to their different inappropriate effects, they have created a major concern in environmental control practices. Metronidazole (MTN) is an example of these antibiotics. This study was performed to investigate the efficiency of ozonation process (SOP) in MTN removal from aqueous solutions. The solution pH (3-12), reaction time and initial MTN concentration (1-40 mg/L) were investigated for their effects on efficiency of the removal process. The MTN concentration was analyzed by HPLC. Biodegradability improvement and mineralization rate were studied by BOD5/COD and TOC tests, respectively. The optimum pH for SOP was 10. The best compatibility for drug degradation kinetic was found with pseudo-second order (liner type II) model. The BOD5/COD increased from 0.09 in SOP influent to 0.33 in SOP effluent and the MTN mineralization rate was about 68%. Higher ozone decomposition in alkaline pH increased the radical production and improved removal efficiency. Moreover, higher mineralization rate reduced the environmental risks of effluent discharges.