RESUMEN
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, 2500â¯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 (1â¯mL) were collected during the degradation. After 6â¯h of H2O2 electrogeneration, the manganese concentration in the RB5 solution was only 23.1⯱â¯1.2⯵gâ¯L-1. It was estimated that approximately 60⯵gâ¯L-1 (<0.2%) of manganese migrated from the GDE to the solution after 12â¯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 (â¼93%) and 91% of mineralization. The 3% NFMnO2/C GDE is promising for RB5 degradation.