2026-04-17T13:12:38Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1767082025-12-04T20:53:54Zcom_2072_1057col_2072_478796col_2072_478917

Paired electrochemical removal of nitrate and terbuthylazine pesticide from groundwater using mesh electrodes Oriol, Roger Brillas, Enric Cabot Julià, Pere-Lluís Cortina Pallàs, José Luis Sirés Sadornil, Ignacio Oxidació electroquímica Hidrologia d'aigües subterrànies Plaguicides Electrolytic oxidation Groundwater hydrology Pesticides Groundwater is one of the main freshwater resources on Earth, but its contamination with NO3− and pesticides jeopardizes its viability as a source of drinking water. In this work, a detailed study of single electro-oxidation (EO) and electrodenitrification and paired EO/electrodenitrification processes has been undertaken with simulated and actual groundwater matrices containing 100 mg dm−3 NO3− and/or 5 mg dm−3 terbuthylazine pesticide. Galvanostatic electrolyses were made with 500 cm 3 of solutions at pH 4.0-10.5 and 250-1000 mA in tank reactors with a RuO2 or boron-doped diamond (BDD) anode and one or two Fe cathodes, all of them in the form of meshes. Most of NO3− removals agreed with a pseudo-first-order kinetics. In Cl−-free media, NH4+ predominated as electroreduction product. In chloride media, a greater amount of N-volatiles was determined alongside a slower electrodenitrification, especially with RuO2 due to the partial re-oxidation of electroreduction products like NH4+ by active chlorine. The pesticide decays were also fitted to a pseudo-first order kinetics, and its presence led to a smaller release of N-volatiles. Overall, BDD always favored the pesticide degradation thanks to the action of BDD(¿OH), whereas RuO2 was preferred for electrodenitrification under some conditions. The EO/electrodenitrification of groundwater was successful once the matrix was softened to minimize its hardness. The NO3− concentration was reduced below the limit established by the WHO. Overall, the BDD/Fe cell was more suitable than the RuO2/Fe cell because it accelerated the pesticide removal with a simultaneous high degree of NO3− electroreduction. However, it produced toxic chlorate and perchlo- rate. A final post-treatment with an anion exchange resin ensured a significant removal of both ions, thus increasing the viability of the electrochemical approach to treat this type of water. Chromatographic analyses revealed the formation of ten heteroaromatic products like desethyl-terbuthylazine and cyanuric acid, alongside oxalic and oxamic as final short-chain carboxylic acids. 2021-04-26T15:10:11Z 2023-04-09T05:10:20Z 2021-04-09 2021-04-26T15:10:11Z info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion 0013-4686 https://hdl.handle.net/2445/176708 711872 eng Versió postprint del document publicat a: https://doi.org/10.1016/j.electacta.2021.138354 Electrochimica Acta, 2021, vol. 383, p. 138354 https://doi.org/10.1016/j.electacta.2021.138354 cc-by-nc-nd (c) Elsevier Ltd, 2021 http://creativecommons.org/licenses/by-nc-nd/3.0/es info:eu-repo/semantics/openAccess application/pdf Elsevier Ltd Articles publicats en revistes (Ciència dels Materials i Química Física)