Preparation Of Rare Earth Doped Ti/Sb-SnO2 Electrode And Study Of Its Electrocatalytic Degradation Of Pesticide Wastewater

At electrode preparation, the author tried to do single factor experiments and optimized the parameters of electrode preparation, then characterized and analyzed electrode properties. At electrode application, the author used the electrode to electro-catalytic degradation of the nitenpyram simulated pesticide wastewater and optimized the electrolysis condations, then studied the degradation mechanism.The paper introduced how to prepare Pr and Dy doped double coating electrode by sol-gel method. The main content includes single factor experiments and optimized experiment of rare earth doped. The electrode material and preparation method are the main factors that affected the electrode capability parameters. The author determined electrode parameters of rare earth doped and the preparation method. The author used orthogonal design and uniform orthogonal design to optimize the process parameters of rare earth Pr, Dy doped Ti/Sb-SnO2 electrode. The result showed that the parameters that determined by uniform orthogonal design were better than orthogonal design. The first layer doped Pr; the second layer doped Dy. And the mole concentration of Sn:Sb:Pr is 100:5:0.75; Sn:Sb:Dy is 100:5:1.25. The best molar ratio between citrate ligand and metal ion is M=0.5. The coating sintering temperature is 630℃. The sintering rate is 5℃/min. Sintering time is 60 min.In order to better study the characteristics of high-performance electrode, the electrode performance were characterized and analyzed in the paper. Experiment mainly used scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), potentiodynamic scanning curve analysis and detection method to characterize and analyze surface morphology, crystal structure, elemental composition, oxygen evolution potential of Ti/Sb-SnO2 double coated electrode doped by Pr, Dy. The results showed that rare earth Pr, Dy doping and preparation of double layer made the electrode surface is more compact and uniform, surface refinement. And the electrocatalytic activity is greatly increased.The electro-catalytic oxidation decomposition of nitenpyram simulated wastewater using self-made of the Pr, Dy doped nano Ti/Sb-SnO2 electrode as anode was investigated adding a certain amount of Na2SO4 as the supporting electrolyte. rare earth Pr, Dy doped Ti/Sb-SnO2 electrode as anode and processed. Orthogonal test method and uniform orthogonal were used to optimize the reaction conditions of electrolysis. Using UV spectrophotometry to detect the degradation process of nitenpyram and using CODcr to reflect the end of degradation. The optimal parameters on using of a refractory anode to discharge of organic pesticide wastewater were obtained. The current density is 12.5 mA/cm2, The concentration of supporting electrolyte Na2SO4 is 0.4 mol/L, the distance of plate is 3 cm-5 cm, the degradation time is 2 h, and pH of initial solution is 7.2 without adjusting. For the initial concentration of 40 mg/L of nitenpyram wastewater, after 1 h of electro-catalytic decomposition under optimal degradation conditions, CODcr removal rate was above 70%. TOC removal rate was above 60%. Nitenpyram removal rate was above 90%. For the initial concentration of 100 mg/L of nitenpyram wastewater, after 5 h of electro-catalytic decomposition under optimal degradation conditions, CODcr removal rate was above 98%. Nitenpyram removal rate was above 99%.This research has enriched the theory of doped Ti/Sb-SnO2 electrode and explored a new method for the electro-catalytic degradation of pesticide wastewater treatment.