Environmental aspects of UV-C-based processes for the treatment of oxytetracycline in water

• Published in: Environmental pollution (1987) 2021-05, Vol.277, p.116797, Article 116797
• Main Authors: Stankov, Vladimir, Stankov, Mirjana Novak, Cvetnić, Matija, Sigurnjak Bureš, Marija, Ukić, Šime, Kučić Grgić, Dajana, Lončarić Božić, Ana, Kušić, Hrvoje, Bolanča, Tomislav
• Format: Article
• Language: English
• Subjects: Biodegradability; Byproducts; Chromatography, Liquid; Hydrogen Peroxide; Kinetics; Oxidation-Reduction; Oxytetracycline; Oxytetracycline - analysis; Oxytetracycline - toxicity; Photolysis; Tandem Mass Spectrometry; Toxicity; Ultraviolet Rays; UV-C-Based processes; Water; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - toxicity; Water Purification
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2021.116797

This study is focused on oxytetracycline (OTC) degradation by direct photolysis (UV–C) and photobased advanced oxidation processes (AOPs) (UV–C/H2O2 and UV-C/S2O82−). OTC degradation pathways were revealed by LC-MS/MS and GC-MS/MS analyses. The evolution/degradation profiles of 12 detected byproducts were correlated with changes in biodegradability and toxicity toward Vibrio fischeri recorded during the treatment. Both photobased AOPs yielded higher OTC degradation and mineralization rates than direct photolysis. The OTC degradation pathway was found to be rather specific regarding the main reactive species (HO• or SO4•-)/mechanism, yielding different patterns in toxicity changes, while biodegradability profiles were less affected. Biodegradability was correlated with the observed degradation and mineralization kinetics. The recorded toxicity changes indicate that byproducts formed by initial OTC degradation are more toxic than the parent pollutant. The prolonged treatment resulted in the formation of byproducts that contributed to a decrease in toxicity and an increase in biodegradability, as particularly emphasized in the case of UV-C/S2O82−. [Display omitted] •Oxytetracycline (OTC) solution was treated UV-C based processes.•OTC degradation and mineralization were much faster by photo-AOPs than by UV-C photolysis.•12 OTC by-products were identified and their pattern of changes during treatments were monitored.•Changes in biodegradability of OTC solution reflected mineralization.•Toxicity changes of OTC solution can be associated with the pattern of changes of formed by-products.