Effects of water components on the photocatalytic and ozone oxidation of oxytetracycline antibiotic

Abstract

Antibiotics are widely used to treat diseases in human and animals and to improve growth efficiency of animal. Antibiotics applied to the organism can be excreted up to 90 %. Therefore, human and animal excreta can contain high amount of antibiotics that constitute the main source of antibiotic pollution in the environment. Since the conventional treatment methods are inefficient for the removal of them, alternative treatment methods are necessary to control antibiotic pollution, which mainly causes the development of antibacterial resistance in microorganisms. In this study, photocatalytic and ozone oxidation processes were investigated for the treatment of a tetracycline (TC) group antibiotic in aqueous solution under different experimental conditions. While the application of ozonation process resulted in the complete removal of 0.1 mM TC antibiotic in a few minutes, the photocatalytic process required 60 min to achieve the same result. For both oxidation processes the highest oxidation of antibiotic was obtained at pH 7. The antibiotic treatment performances of both photocatalytic and ozone oxidation were also investigated in the presence of Ca2+, HCO3-, NO3-, PO43-, SO42-, Cl- ions, and humic acid to observe the effect of water components on the degradation of antibiotic. It was determined that all these water components decreased the photocatalytic and ozone oxidation efficiency. The abatement in photocatalytic reaction rate depended on the rate constant of hydroxyl radical scavenging reaction of anions added to the solution as water constituent whereas this relation was not observed for ozonation process.|Keywords: Antibiotic, Oxytetracycline, Ozone oxidation, Photocatalytic Oxidation, Titanium dioxide