Electrochemical oxidation of paraquat in neutral medium

• Published in: Electrochimica acta 2015-09, Vol.176, p.1010-1018
• Main Authors: Cartaxo, M.A.M., Borges, C.M., Pereira, M.I.S., Mendonça, M.H.
• Format: Article
• Language: English
• Subjects: anodic oxidation; Co2FeO4 electrode; electrochemical conversion; mass spectrometry; paraquat
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2015.07.099

[Display omitted] •Electrochemical oxidation of paraquat using different electrodes was investigated.•Anodic and cathodic processes contribute to paraquat oxidation.•Monopyridone and dipyridone derivatives are paraquat main by-products.•With Pt/steel electrodes a conversion of 79% was obtained, after 1.5h of electrolysis.•With Co2FeO4/ Co2FeO4 a conversion of 64% was observed after 3h of electrolysis. Steel, Pt and pelleted Co2FeO4 electrodes were used for the electrochemical oxidation of paraquat in aqueous solutions at room temperature. The oxide electrodes were characterized by cyclic voltammetry. Paraquat electrochemical oxidation was carried out by electrolysis at constant current and monitored by UV–vis absorbance measurements. Different anode/cathode pairs were used. After 1.5h of electrolysis the highest removal (≈79%), was obtained with the electrode pair Pt/steel followed by Co2FeO4/Pt (≈55%), corresponding to the paraquat oxidation by a conversion mechanism. Removals of ≈64% were obtained with Co2FeO4 / Co2FeO4 after 3h of electrolysis. Mass spectrometry analysis indicates that the main intermediate oxidation products were monopyridone and dipyridone derivatives.