Preparation And Electrocatalytic Oxidation Of Ti-based Metal-oxide Electrodes For Phenol

This paper focused on the preparation and modification of Ti-based metal-oxide electrodes. The electrocatalytic oxidation performance for phenol, modification and process conditions optimization for phenol degradation of electrodes were studied. The specific research contents and results were summarized as follows:Ti/SnO2-Sb2O3, Ti/SnO2-Sb2O3/PbO2and Ti/SnO2-Sb2O3/MnO2electrodes were prepared by electrodeposition. The three electrodes were characterized with scanning electron micrograph, cyclic votammetry, oxygen evolution polarization curve, Tafel curve and life test of electrodes respectively. Meanwhile, free radical HO-forming during the electrolysis of electrodes and the three electrodes’electrocatalytic activity for phenol were also investigated. Experimental results showed that the Ti/SnO2-Sb2O3electrode had the highest oxygen evolution potential and the most free radical HO-which led to its best electrocatalytic activity. Phenol degradation ratio on it reached85.9%, but its operational life and corrosion-resistant character were inferior to Ti/SnO2-Sb2O3/PbO2electrode. Besides, oxidation degradation of phenol all followed the first reaction kinetics on the three electrodes.The Fe-PbO2electrode was modified by adding surfactant Triton X-100with different concentration into the plating solution to prepare Fe-PbO2/TX-100electrode with high activity. Scanning electron micrograph, X-ray diffraction, oxygen evolution polarization curve, Tafel curve and life test of electrodes were used to characterize electrodes. Free radical HO-studied forming during the electrolysis of electrodes, effect of Triton X-100with different concentration on the electrocatalytic activity wes compared by the degradating phenol experiment. Experimental results indicated that the surfactant could control the growing speed of cystal grain on the surface of electrodes during the electrodeposition so as to make the size of cystal grain decrease and specific area of electrodes increase, which resulted in better electrocatalytic activity. The experiment of degradating pheol showed that Fe-PbO2electrode had the best electrocatalytic activity and its degradating ratio of phenol was89.8%. Electrochemical experimental results showed modified electrodes had higer potential of oxygen evolution, longer operational life, better corrosion-resistant character and formed more free radical HO.Ti/SnO2-Sb2O3/Fe-PbO2/TX-100electrode was used to treat simulated phenol wastewater. Effect of five process conditions on degradation of phenol, which included concentration of electrolyte, current density, original concentration of pheol, electrode gap and pH of solution, was investigated. Experimental results indicated the optimum process condition for phenol degradation on this electrode:concentration of electrolyte was0.5mol/L, current density was60mA/cm2, original concentration of phenol was250mg/L, electrode gap was2cm and pH of solution was7. After two hours, the degradation ratio of phenol reached83.7%in the optimum process condition. The degradation mechanism of phenol was initially explored with ultraviolet-visible spectrum and using isopropanol as capture of HO.