Utilization of SnO2 anodes to the electrochemical degradation of biorefractory dyes

This study deals with the characterization of electrochemical properties of doped SnO2 anodes by cyclic voltammetry (CV) and their use for Reactive Blue 4 azo dye (RB4) degradation. The experiments were carried out by using Ti/Ru02/SnO2-SbO5-RuO2 anodes (94:3:3 Sn:Sb:Ru molar ratio in precursors solution) prepared by thermal decomposition method. Cyclic voltammograms were recorded at a scan rate of 0.05 V/s and potential range from 0 V to 1.5 V vs. SCE in 0.1 M Na2SO4 and 0.1 g/L RB4. The supporting electrolyte was 0.1 M Na2SO4. Degradation experiments were carried out in solutions of 0.1 g/l DYE IN 0.1 m Na2SO4, applied current densities of 25, 50, 75 and 100 A/m2 at various electrolysis times and pH values: 6.2; 11 and 3. The cyclic voltammograms showed that the oxidation of dye could occur under conditions of simultaneous O2 evolution. The best value for the colour removal efficiency was about 99% for an applied current density of 100 A/m2 and 120 minutes of electrolysis at any pH value.