Study On Ti/SnO₂-Sb₂O₅ Modified Electrodes And Application To Dye Wastewater Treatment

The problem of dye pollution is getting worse and worse now. How to efficiently dispose dye wastewater has become an issue commonly concerned by many environmentalists. Due to the complexity and recalcitrance of dye wastewater,traditional treatment methods are limited. Nevertheless, the electrocatalysis oxidation technology can effectively destroy the stable structure of refractory organics.Considering advantages of its own, the electrocatalysis oxidation technology has been applied for decolorization to disposal dye wastewater in this article, and its degradation mechanism will be studied thoroughly.Ti/Sb-SnO2 electrodes were modified with nitrogen-doped graphene nanosheets(N-GNS) and titanium nitride (TiN), respectively, and were successfully fabricated by the sol-gel and dip coating method in this article. The effects of experimental conditions were investigated through some characterizing methods such as X-ray diffraction (XRD),scanning electron microscopy (SEM),X-ray photoelectron spectroscopy (XPS), and electrochemical measurements and so on. The results indicated that under the calcination condition of 600 ?,Ti/SnO2,Sb2O5-N,GNS electrode had the best performance, and its oxygen evolution potential reached 2.0V(vs. SCE). Under the condition of 4% dopant ratio and a 1.457 sol viscosity, the surface of Ti/SnO2-Sb2O5-TiN electrode was smooth and dense, and its oxygen evolution potential reached 2.2V(vs. SCE).The electrochemical dye decolorization analysis demonstrated that Ti/Sb-SnO2-NGNS and Ti/SnO2-Sb2O5-TiN both presented efficient electrocatalytic performance for methylene blue and orange II decolorization. In the decolorization process of methylene blue and orange II, Ti/SnO2-Sb2O5 -NGNS electrode calcined at 600 ? and Ti/SnO2-Sb2O5 -TiN electrode with 4% TiN doping ratio would achieve the best decolorization performance. Decolorization results were consistent with the results of electrode characterization and results of electrochemical measurements. The optimal process parameters for degrading methylene blue and orange ? on Ti/SnO2-Sb2O5 -NGNS electrode were: Na2SO4 concentration was 0.25mol/L,pH was 10, the current density was 20mA/cm2, and the initial dye concentration was 50mg/L.Under this condition after 100 min degradation, Ti/SnO2-Sb2O5 electrode decolorization rates of methylene blue and orange ? reached 43.8% and 46.2%,Ti/SnO2-Sb2O5 -NGNS electrode decolorization rates of methylene blue and orange ? reached 97.7% and 99%, respectively. The optimal process parameters for degrading methylene blue and orange ? on Ti/SnO2-Sb2O5 -TiN electrode were:Na2SO4 concentration was 0.25mol/L, pH was 4, current density was 20mA/cm2, and initial dye concentration was 50mg/L. Under this condition after 100 min degradation,Ti/SnO2-Sb2O5 electrode decolorization rates of methylene blue and orange ? reached 41.2% and 72.3%,Ti/SnO2-Sb2O5-TiN electrode decolorization rates of methylene blue and orange ? reached 99.7% and 95.8%, respectively.