Advances in Environmental Research, Vol. 7, No. 3 (2018) 213-223 DOI: https://doi.org/10.12989/aer.2018.7.3.213 213 Copyright © 2018 Techno-Press, Ltd. http://www.techno-press.org/?journal=aer&subpage=7 ISSN: 2234-1722 (Print), 2234-1730 (Online) Comparison of TiO2 and ZnO catalysts for heterogenous photocatalytic removal of vancomycin B Giusy Lofrano 1 , Can Burak Özkal 2 , Maurizio Carotenuto 1 and Süreyya Meriç *2 1 Department of Chemistry and Biology- University of Salerno- via Giovanni Paolo II, 132- 8484 Fisciano (SA), Italy 2 Tekirdağ Namik Kemal University Environmental Engineering Department Çorlu, Tekirdağ, Turkey (Received December 6, 2016, Revised April 18, 2017, Accepted May 3, 2017) Abstract. Continuous input into the aquatic ecosystem and persistent structures have created concern of antibiotics, primarily due to the potential for the development of antimicrobial resistance. Degradation kinetics and mineralization of vancomycin B (VAN-B) by photocatalysis using TiO2 and ZnO nanoparticles was monitored at natural pH conditions. Photocatalysis (PC) efficiency was followed by means of UV absorbance, total organic carbon (TOC), and HPLC results to better monitor degradation of VAN-B itself. Experiments were run for two initial VAN-B concentrations (20-50 mgL -1 ) and using two catalysts TiO2 and ZnO at different concentrations (0.1 and 0.5 gL -1 ) in a multi-lamp batch reactor system (200 mL water volume). Furthermore, a set of toxicity tests with Daphnia magna was performed to evaluate the potential toxicity of oxidation by-products of VAN-B. Formation of intermediates such as chlorides and nitrates were monitored. A rapid VAN-B degradation was observed in ZnO-PC system (85% to 70% at 10 min), while total mineralization was observed to be relatively slower than TiO2-PC system (59% to 73% at 90 min). Treatment efficiency and mechanism of degradation directly affected the rate of transformation and by- products formation that gave rise to toxicity in the treated samples. Keywords: photocatalysis; vancomycin B; degradation; mineralization; ecotoxicity; transformation by- products; TiO2; ZnO 1. Introduction Antibiotics are released into aquatic environment by different pathways since they are among the most frequently prescribed pharmaceuticals in human and veterinary treatment of bacterial infections. Due to their continuous input into the aquatic ecosystem at lower inhibitory concentrations of antibiotics gives a rise to growing potential for the development of antimicrobial resistance (Varela et al. 2013, Sharma et al. 2016, Lofrano et al. 2017, Inyinbor et al. 2018). Several treatment alternatives have been attempted to remove antibiotics. Literature studies showed that photocatalysis process using TiO2 or ZnO nanoparticles enables to degrade effectively antibiotics in suspended (Chatzitakis et al. 2008, Elmolla and Chaudhuri 2010, Dimitrakopoulou et al. 2012, Lofrano et al. 2014, 2016, Ozkal et al. 2016, Vaiano et al. 2015, Van Doorslaer et al. Corresponding author, Professor, E-mail: smeric@nku.edu.tr