ADVANCED OXIDATION/REDUCTION TECHNOLOGIES: AN PERSPECTIVE FROM IBEROAMERICAN COUNTRIES Diclofenac photodegradation with the Perovskites BaFe y Ti 1-y O 3 as catalysts Ana Sofia Rodrigues 1 & Jefferson E. Silveira 1,2 & Jaime Carbajo 2 & Juan A. Zazo 2 & Jose A. Casas 2 & Annabel Fernandes 1 & Maria José Pacheco 1 & Lurdes Ciríaco 1 & Ana Lopes 1 Received: 8 July 2020 /Accepted: 18 October 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Perovskite oxides BaFe y Ti 1-y O 3 , with y = 0, 0.6, 0.8 and 1, were prepared by ceramic (CM) and complex polymerization methods (CPM) and utilized in UV-LED (365 nm) photocatalytic degradation assays of 25 mg L -1 diclofenac (DIC) model solutions. BaTiO 3 -CM was also used in the photocatalytic degradation test of a real mineral water for human consumption spiked with 2 mg L -1 DIC. The XRD patterns of the synthesized perovskites showed cubic structure for those prepared by CPM, with distortions of the cubic lattice to hexagonal or tetragonal when prepared by CM, except for BaTiO 3 . All the perovskites showed good catalytic activity, higher than photolysis, except BaFeO 3 -CM that presented similar results. BaTiO 3 -CM and CPM and BaFeO 3 -CPM were also utilized in UV-LED photocatalytic DIC degradation assays with peroxydisulfate addition. BaFeO 3 -CPM and BaTiO 3 - CPM showed better ability to persulfate activation, but the highest mineralization degree was obtained with BaTiO 3 -CM. This last perovskite was also able to perform DIC degradation in a real matrix. The studied oxides show potentiality for photocatalytic degradation of organic compounds, with or without persulfate addition. A degradation mechanism is proposed. Keywords Perovskites . BaFe y Ti 1-y O 3 . Diclofenac . Photocatalysis . Peroxydisulfate . LED reactor Introduction Water pollution is a consequence of water body contamination by human activities. Among the possible sources of water contamination, the increasing production and consumption of pharmaceuticals worldwide are of great concern (Carere et al. 2013). These compounds are continuously introduced into the aquatic environment due to their domestic, hospital and veterinary use, and their potential biological activity, associated with low removal during conventional wastewater treatment processes, can lead to adverse effects on the aquatic ecosystems and risk public health (Santos et al. 2010; Carere et al. 2013). In fact, according to Rabiet et al. (2006), pharma- ceuticals like paracetamol, caffeine and diclofenac, the most frequently detected, are already found in drinking water reservoirs. Diclofenac, 2-[2,6-dichlorophenyl)amino]-benzeneacetic acid, a common nonsteroidal anti-inflammatory drug, used in both human and veterinary medicine, was one of the first pharmaceuticals included in the list of priority substances adopted by the European Union, Directive 2013/39/ EU (2013), due to its bioavailability and bioaccumulation in aquatic biota (Buser et al. 1998; Johnson et al. 2013; Vieno and Sillanpää 2014; Acuña et al. 2015; Carere et al. 2015; Toufexi et al. 2016; Bonnefille et al. 2018). Due to its rapid urinary excretion and poor biodegradation, diclofenac is one of the most frequently detected pharmaceuticals in sewage and surface waters (Ziylan et al. 2014). Different studies revealed the presence of diclofenac in wastewaters, surface waters and waters for human consumption all over the world (Tixier et al. 2003; Rabiet et al. 2006; Roberts and Thomas 2006; Kim et al. Responsible Editor: Vítor Pais Vilar Supplementary Information The online version contains supplementary material available at https://doi.org/10.1007/s11356-020- 11328-4. * Lurdes Ciríaco lciriaco@ubi.pt 1 FibEnTech-UBI, Department of Chemistry, Universidade da Beira Interior, 6201-001, Covilhã, Portugal 2 Chemical Engineering Department, Autonomous University of Madrid, Cantoblanco, 28049 Madrid, Spain Environmental Science and Pollution Research https://doi.org/10.1007/s11356-020-11328-4