Preparation Of Yb Doped Ti/SnO₂-Sb Electrode And Study On Its Electrocatalytic Degradation Of Main Chlorophenol Compounds Wastewater

Quick and efficient disposal of wastewater containing persistent organic pollutants was alwalys the difficulty of environmental governance. Chlorinated phenols are a kind of typical persistent organic pollutants.2-Chlorophenol, 2,4-Dichlorophenol and 2,4,6-Trichlorophenol were chosen to proceed electrochemical oxidation degradation study in this paper. Use Pechini method to prepare electrodes and find that doping rare earth ytterbium (Yb) could improve the electrochemical performance of Ti/SnO2-Sb electrode. Confirm the appropriate electrode preparation process parameters, the calcination temperature was 660 ℃, the mole ratio of Sn and Yb in coating liquid was 100:1.0, and the number of coating layers was 12. Under the optimum calcination temperature and the number of coating layers, take gradient optimization for the mole ratio of Sn and Yb in coating liquid and ensure the optimal gradient ratios. From the electrode substrate to outward for the optimal gradient coating electrode, the mole ratios of Sn and Yb in the coating were 100:(0-0.25-0.5-0.75-1), and the number of coating layers were 3-2-2-2-3 in turn. Take physical and chemical characterization analysis for undoped Ti/SnO2Sb electrode, Yb doped Ti/SnO2-Sb electrode and gradient coating electrode. The physical and chemical characterization of gradient coating electrode was the most superior. Surface became denser for the electrode coating, the growth of grains was full and uniform, and the mean grain size of the grain was smaller. The electrode had the higher oxygen evolution potential, well electrical conductivity, good electrochemical performance, the longer service life and so on. Determine the optimum parameters of the degradation for the gradient coating electrode that dislodged chlorine phenol by electrochemical process. The current density was 15 mA/cm2, the concentration of electrolyte was 0.3 mol/L, the plate spacing was 2.5 cm, the initial pH value of solution was 5.0 and magnetic stirring. After 150min electrochemical degradation, the removal of 2-CP, TOC2-CP,2,4-DCP, TOC2,4-DCP and TOC2>4,6-TCP were 91.53%,71.18%,93.02%,63.83% and 60.26% in this condition, respectively. By the means of mass spectrometry, put forward the degradation paths of the 2-CP,2,4-DCP and 2,4,6-TCP. The degradation process could be described as follow, OH that formed on the electrode surface attacked the benzene ring and Cl, and chlorine phenol molecule was degraded little by little.