Cobo Golpe, MiguelFernández Fernández, VictoriaArias, T.Ramil Criado, MaríaCela Torrijos, RafaelRodríguez Pereiro, Isaac2022-08-112022-08-112022Journal of Environmental Chemical Engineering 10 (2022) 107854http://hdl.handle.net/10347/29051Tramadol (TRA) is a poorly biodegradable pharmaceutical, ubiquitously distributed in the aquatic environment. Herein, we present a thorough comparison of two conventional (UV and chlorination) and two advanced oxidative processes (UV-H2O2 and UV-chlorine), in terms of TRA removal efficiency and transformation products (TPs) formation. The performance of these processes was evaluated in different complexity water samples, previously adjusted at neutral pH. Using 1 mg L−1 as initial concentration of oxidant, UV-chlorine was the most effective process followed by UV-H2O2, direct photolysis and chlorination. The efficiency of the investigated treatments decreased for surface and wastewater samples compared to model solutions. Despite this limitation, the UV-chlorine treatment removed more than 70% of TRA measured in wastewater samples after 5 min of UV irradiation, in presence of 10 mg L−1 of chlorine. UV-chlorine involved additional degradation routes to those described for the rest of treatments, including the formation of tramadol-N-oxide, several chlorinated derivatives, and the volatile species chloroform, 1,1-dichloroacetone and anisole. Some of these specific TPs might pose a similar toxicity to that associated to the parent compound; however, their maximum formation yields remained below 2.5%, decreasing steady for reaction times longer than 5 mineng© 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by- nc-nd/4.0/)Attribution-NonCommercial-NoDerivatives 4.0 Internacionalhttp://creativecommons.org/licenses/by-nc-nd/4.0/TramadolOxidative processesLiquid chromatography mass spectrometryRemoval efficiencyTransformation productsjournal article10.1016/j.jece.2022.1078542213-3437open access