Application and stability of cathodes with manganese dioxide nanoflowers supported on Vulcan by Fenton systems for the degradation of RB5 azo dye. (October 2018)

• Record Type: Journal Article
• Authors: Aveiro, L.R.; Da Silva, A.G.M.; Candido, E.G.; Antonin, V.S.; Parreira, L.S.; Papai, R.; Gaubeur, I.; Silva, Fernando L.; Lanza, M.R.V.; Camargo, P.H.C.; Santos, M.C.
• Is Part Of: Chemosphere. Volume 208(2018)
• Page Start: 131
• Page End: 138
• Publication Date: 2018-10
• Subjects: Manganese dioxide nanoflowers -- Boron-doped diamond -- Heterogeneous electro-Fenton -- Homogeneous electro-Fenton; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.05.107
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: This work describes the electrochemical degradation of Reactive Black 5 (RB5) by two methods: electrochemical and photo-assisted electrochemical degradation with and without a Fenton reagent. Two anodes were used, Pt and boron-doped diamond (BDD, 2500 ppm), and the cathode was 3% MnO2 nanoflowers (NFMnO2 ) on a carbon gas diffusion electrode (GDE). An electrochemical cell without a divider with a GDE with 3% w/w NFMnO2 /C supported on carbon Vulcan XC72 was used. The decolorization efficiency was monitored by UV–vis spectroscopy, and the degradation was monitored by Total Organic Carbon (TOC) analysis. For dissolution monitoring, aliquots (1 mL) were collected during the degradation. After 6 h of H2 O2 electrogeneration, the manganese concentration in the RB5 solution was only 23.1 ± 1.2 μg L −1 . It was estimated that approximately 60 μg L −1 (<0.2%) of manganese migrated from the GDE to the solution after 12 h of electrolysis, which indicated the good stability of the GDE. The photoelectro-Fenton-BDD (PEF-BDD) processes showed both the best color removal percentage (∼93%) and 91% of mineralization. The 3% NFMnO2 /C GDE is promising for RB5 degradation. Highlights: The (PEF-BDD) processes showed both the best color removal 93% and mineralization 91%. The results indicate the good stability of 3% NFMnO2 /C GDE during electrolysis. The 3% NFMnO2 /C GDE is promising for RB-5 degradation.