The Preparation And Application Of Lead Dioxide Electrode Modified With Erbium

Lead dioxide electrode has low price, high oxygen over potential, as well asgood catalytic activity, so it is widely used in the synthesis of inorganic chemicals,organic synthetic material, organic waste water treatment, and other fields. On thebasis of previous research in this field, the main work of this thesis can besummarized as follows:Sodium hypochlorite has strong oxidizing, widely used as fabric bleaching,surface purification, odor removal, and water disinfection. In this thesis, theTi/SnO₂-Sb2O3/PbO₂electrode prepared by electrodeposition method was used asanode for electrochemical synthesis of sodium hypochlorite. The active chlorinecontent in sodium hypochlorite was analysed by iodometry. Through experimentapproach, the optimum conditions of electrochemical synthesis of sodiumhypochlorite show that when the temperature is35℃, solution pH is1, electrolytictime is50min, current density is90mA·cm^-2, initial concentration of sodiumchloride is1.25mol·L^-1, the active chlorine content can reach542.66mg·L^-1.In order to strengthen the catalytic activity of lead dioxide electrode, this paperstudied the rare earth erbium modification of lead dioxide electrode. The bestelectrodeposition conditions were determined by phenol degradation experiments.Then, SEM, EDS, XRD, EIS, CV, LSV, COD and fluorescence spectrophotometricanalysis were used to characterize the microstructure and electrochemical propertiesof the Er modified electrodes. SEM, EDS and XRD tests show that the surfacemorphology of Er-PbO₂electrode has changed a lot, the crystal form of PbO₂ismainly β-PbO₂, the particle size is decreased and the surface area is increased. Theelectrochemical performance tests show that erbium modified lead dioxide electrodehas smaller electrochemical reaction resistance, higher oxygen evolution potential,and better catalytic activity.The treatment of refractory organic dye wastewater is one of the seriousproblems in the field of water processing. In this thesis, orange Ⅱsolution was regarded as simulated dye wastewater and electrocatalytic oxidation technology wasapplied to treat the wastewater using erbium modified lead dioxide electrode as anodeand stainless steel as cathode. Results show that when the temperature is40℃, pH is7, current density is20mA·cm^-2, the initial concentration of orange Ⅱis100mg·L^-1,the degradation ratio can reach to96.3%in2.5h. The kinetics study indicates thatelectrocatalytic oxidation of orange Ⅱaccords with pseudo-first order kinetic law.Fluorescence spectrophotometric analysis, UV-visible spectra and infrared spectraanalysis show that the high catalytic oxidation activity of Er-PbO₂electrode destroysthe structure of azo and benzene ring of orange Ⅱthoroughly, and orange Ⅱwasoxidized to CO₂, H2O or other small molecules finally.