Paired electrochemical removal of nitrate and terbuthylazine pesticide from groundwater using mesh electrodes
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-04-09 |
| Journal | Electrochimica Acta |
| Authors | Roger Oriol, Enric Brillas, Pere LluıÌs Cabot, JosĂ© Luis Cortina, Ignasi SirĂ©s |
| Institutions | Universitat PolitĂšcnica de Catalunya, Universitat de Barcelona |
| Citations | 16 |
Abstract
Section titled âAbstractâGroundwater 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 cm3 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 Clâfree 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( \n \nOH), 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 perchlorate. 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.
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
Section titled âReferencesâ- 2018 - An overview of nitrate sources and operating processes in arid and semiarid aquifer systems [Crossref]
- 2012 - Powering denitrification: the perspectives of electrocatalytic nitrate reduction [Crossref]
- 2007 - Nitrate removal from groundwater by a novel three-dimensional electrode biofilm reactor [Crossref]
- 2001 - New methods of nitrate removal from water [Crossref]
- 2009 - Simultaneous reduction of nitrate and oxidation of by-products using electrochemical method [Crossref]
- 2005 - Paired electrolysis in a solid polymer electrolyte reactor-simultaneously reduction of nitrate and oxidation of ammonia [Crossref]
- 2005 - Application of a solid polymer electrolyte reactor to remove nitrate ions from wastewater [Crossref]
- 2007 - Influence of the concentration and the nature of the supporting electrolyte on the electrochemical reduction on tin cathode [Crossref]
- 2008 - Influence of nitrate concentration on its electrochemical reduction on tin cathode: identification of reaction intermediates [Crossref]
- 2008 - Study of the electroreduction of nitrate on copper in alkaline solution [Crossref]