ADVANCED OXIDATION TECHNOLOGIES: STATE-OF-THE-ART IN IBERO-AMERICAN COUNTRIES Advanced oxidation of antihypertensives losartan and valsartan by photo-electro-Fenton at near-neutral pH using natural organic acids and a dimensional stable anode-gas diffusion electrode (DSA-GDE) system under light emission diode (LED) lighting Diana Martínez-Pachón 1 & Paula Espinosa-Barrera 1 & Javier Rincón-Ortíz 2 & Alejandro Moncayo-Lasso 1 Received: 1 February 2018 /Accepted: 25 June 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract In this work photo-electro-Fenton (PEF) processes using a dimensionally stable anode-gas diffusion electrode (DSA-GDE) system under light emission diodes (LED)-type radiation were used in the degradation of the angiotensin-II-receptor antagonists (ARA II), valsartan (VAL), and losartan (LOS), which are used in the treatment of hypertension diseases, and are considered among the emerging contaminants (ECs). Organic acids as citric, tartaric, and oxalic acids were used as complexing agents of iron ions in order to maintain the performance of the Fenton reaction at near-neutral pH value. The results show that at 3.42 mA/cm 2 after 90 min of electro-Fenton (EF) treatment, degradation of 70% of VAL and 100% of LOS were observed. Total degradation of VAL and LOS was reached with a PEF process at the same time with mineralization of 30%. When citric and tartaric acids were used instead of oxalic acid, similar results were obtained, i.e., total degradation of both compounds, LOS and VAL, after 90 min of treatment. The degradation performance can be attributed to the increase of the initial dissolved iron in the system, facilitating the Fe 3+ /Fe 2+ turnover in the catalytic photo-Fenton reaction and consequently, hydroxyl radical ( • OH) production. In addition, the increased photo-activity of the complexes can be associated with their high capability to complex Fe 3+ and to promote ligand- to-metal charge transfer, which is of key importance to feed Fe 2+ to the Fenton process. The results show that the system evaluated was more efficient to eliminate sartan family compounds using LED lighting in comparison with traditional UV-A lamps used in this kind of work. Moreover, three transformation products of VAL degradation and two transformation products of LOS degradation were identified by high-resolution mass spectrometry (HRMS) using hybrid quadrupole-time-of-flight (QTOF) MS and, at the end of the PEF system, the several organic compounds accumulated and no mineralized were effectively treated in a subsequent aerobic biological system. Keywords Electro-Fenton . Photo-electro-Fenton . Photo-electro-Fenton with organic acids . Emerging contaminants . Sartans . Wastewater treatment . Losartan . Valsartan Introduction The antihypertensives of the sartan family are considered as emerging contaminants (ECs) since they are not regulated, and they are present in aqueous media at very low concentra- tions (ng/L–μg/L). In recent years, their consumption has in- creased significantly (Hiltunen et al. 2015). Most pharmaceu- tical compounds are not completely metabolized after their consumption and consequently are excreted via urine and fe- ces (Jurado et al. 2012). The presence of those kinds of com- pounds may act as disruptors of endocrine systems and affect the development of aquatic and wildlife (Zhang et al. 2015; Responsible editor: Vítor Pais Vilar * Alejandro Moncayo-Lasso amoncayo@uan.edu.co 1 Grupo de Investigación en Ciencias Biológicas y Químicas, Facultad de Ciencias, Universidad Antonio Nariño, Bogotá, D.C., Colombia 2 Grupo de Investigación Fundamental y Aplicada en Materiales, Facultad de Ciencias, Universidad Antonio Nariño, Bogotá, D.C., Colombia Environmental Science and Pollution Research https://doi.org/10.1007/s11356-018-2645-3