APPLICATION OF THE SONO-FENTON AND OZONATION PROCESSES IN THE DEGRADATION OF TETRACYCLINE
Tetracycline antibiotics are among the largest groups of pharmaceutical compounds extensively used in human and veterinary medicine to treat and prevent bacterial infections. In this study, the sono-Fenton process and ozonation were used to degrade tetracycline, and the effects of various operational parameters on tetracycline degradation and its change of toxicity were investigated. The experimental results indicate that the effect of the initial pH level of tetracycline degradation was insignificant from pH 3 to pH 6, but it became increasingly important as the pH became greater than 7. Increasing the ultrasonic power slightly increased the degradation efficiency of tetracycline, suggesting that hydroxyl radicals greatly influence the oxidation of tetracycline. Additionally, the effects of air or oxygen aeration with different flows and reaction temperatures were insignificant. The addition of anions to the reaction solution inhibited the degradation and mineralization of tetracycline from 90% to 31.5% and from 30% to 7.7%, respectively. Furthermore, ozonation elicited superior efficiency in tetracycline degradation, where the optimal reaction conditions were found at pH 3, 0.2 L O3/min and 25oC with almost 100% tetracycline degradation and 34% mineralization. The toxicity of tetracycline was significantly decreased because of mineralization, where the cell viability increased to 89% and 70% from less than 50% of the original tetracycline solution.
Keywords: tetracycline; degradation; sono-Fenton process; ozonation; toxicity