Effect of Ozone on Ooxacillin degradation in aqueous solutions

Abstract

The presence of pharmaceutical compounds in sources of water supply and ecosystems constitutes potential risks with negative effects on the environment, they are called emerging pollutants. Antibiotics receive special attention for the occurrence of bacterial resistance. The effectiveness of ozonation for their degradation is recognized. However, the toxicity of reaction byproducts is debated. The objective of the study was to establish ozonation conditions of amoxicillin and oxacillin model solutions to evaluate the degradation, genotoxic and antimicrobial activity of the ozonized samples to propose an alternative treatment of industrial wastewater. Experimental design 2³was applied with pH (7 and 12), contact times (30 and 60 min) and ozone concentration in the inlet gas (C_O3(g): 70 and 100 mg/L). Oxacillin reached more than 97% of degradation in the first two minutes of reaction and byproducts were generated, which were not completely degraded. The ozonated samples did not show antimicrobial activity and genotoxicity by the Ames test, and the COD and Abs_UV254 values ​​decreased. This indicated that the byproducts were partially degraded and transformed into compounds more oxidized, biodegradable and harmless. For the treatment of industrial wastewater are proposed the operational conditions of C_O3(g): 70 mg/L, pH: 7-8 with 15 min of contact time.