Electrochemical oxidation of aniline using Ti/RuO2-SnO2 and Ti/RuO2-IrO2 as anode

Abstract

Electrocatalytic properties of anode and the electrolyte composition are important parameters influence the degradation efficiency for aniline wastewater. Ti/RuO2-SnO2 and Ti/RuO2-IrO2 have been fabricated using thermal decomposition method and experiments in electrolyte containing 0.05 M Na2SO4, 0.05 M NaCl and 0.05 M Na2SO4+0.005 M FeSO4 at different current density were conducted to study the influence on aniline degradation. Linear sweep voltammetry (LSV) showed that Ti/RuO2-SnO2 had higher oxygen evolution potential and degrade aniline through electrochemical transformation and electrochemical combustion while Ti/RuO2-IrO2 degrade aniline mainly through electrochemical transformation. The study showed that Ti/RuO2-SnO2 had higher electrocatalytic activity towards the degradation of aniline than Ti/RuO2-IrO2 anode in 0.05 M Na2SO4 and in 0.05 M NaCl electrolyte. The maximum TOC removal efficiency for Ti/RuO2-SnO2 was 64.2% at 40 mA cm−2 in Na2SO4 electrolyte while the average MCE was 1.6% and the average ECTOC was 1.51 kWh (g TOC)−1. On the contrary, the maximum TOC removal efficiency for Ti/RuO2-IrO2 was 63.1% at 40 mA cm−2 in NaCl electrolyte while the average MCE was 1.6% and the average ECTOC was 1.95 kWh (g TOC)−1. The presence of Fe2+ in Na2SO4 electrolyte would decrease the TOC removal efficiency except at low current density (20 mA cm−2) for Ti/RuO2-SnO2. These results indicated that Ti/RuO2-SnO2 and Ti/RuO2-IrO2 anode were suitable in Na2SO4 and NaCl electrolyte, respectively, while the presence of Fe2+ would inhibit aniline degradation.