Efficient Electro-Catalytic Oxidation of Ultra-High-Concentration Organic Dye with Ce-Doped Titanium-Based Composite Electrode

Removing high-concentration organic dye from wastewater is of great concern because the hazards can cause serious damage to the environment and human health. In this study, the hybrid dimensionally stable anode (DSA) with a Ce-doped and SnO2-Sb2O5 intermediate layer was fabricated and used for the electro-catalytic oxidation of three kinds of ultra-high-concentration organic dyes. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) confirmed the denser surface structure and morphology of the composite Ti/SnO2-Sb2O5/Ce-PbO2 electrode. Moreover, the electrode exhibited an excellent oxygen evolution potential of 1.58 V. The effect on the removal efficiencies of high concentrations of up to 1 g/L of methyl orange, methylene blue, and neutral red solutions with the above composite electrode was investigated. The research results illustrated that target molecules in the three different dye solutions were rapidly decolorized and decomposed by electro-catalytic oxidation in less than 35 min. Additionally, the degradation process still followed pseudo-first-order kinetics for high-concentration dye solutions. The removal efficiency of Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) for the three dye solutions was more than 98%, and the results of the gas chromatography–mass spectrometry (GC-MS) analysis showed that it had the best degradation effects for neutral red, which decomposed more thoroughly. More than 80 h of accelerated life also revealed excellent performance of the composite electrode in the face of high-concentration dye solution degradation. Considering these results, the Ti/SnO2-Sb2O5/Ce-PbO2 anode could be utilized to treat wastewater containing high-concentration dyes with high efficiency.