Preparation Of Modified PbO₂ Electrode And Its Electrocatalytic Degradation Of Organic Wastewater

As the process of modern industry accelerates,one of the important problems that people urgently need to solve has also emerged,how to comprehensively manage and rationally discharge organic wastewater in industrial production.In industrial wastewater treatment,electrochemical advanced oxidation technology with wider applicability,simple operation and higher efficiency came into being.The core problem of electrocatalytic oxidation of organic polluted wastewater is the development,research and preparation of high energy utilization efficiency,low manufacturing cost and long practical life.In this thesis,electrodeposition method is used to modify the surface active layer of Pb O₂electrode by adding titanium surfactant as the substrate and adding surfactant Hexadecyl trimethyl ammonium Bromide（CTAB）and transition metal Cu.Scanning electron microscope（SEM）,X-ray energy spectroscopy（EDX）and X-ray diffraction（XRD）methods were used to analyze and characterize the surface morphology,element composition and crystal structure of the modified Pb O₂ electrode.SEM results show that the modified Pb O₂ electrode has basically the same shape and maintains the typical pyramidal cubic pyramidal structure.Compared with Ti/Pb O₂,Ti/Pb O₂-CTAB,Ti/Pb O₂-Cu electrodes,the particles on the surface of the Ti/Pb O₂-CTAB-Cu electrode are finer,and the particle distribution is more uniform and dense.XRD results show that due to the CTAB and Cu²⁺,the Pb O₂ electrode grows preferentially on the（101）,（211）,（301）and（202）crystal planes.The crystal size of the Ti/Pb O₂-CTAB-Cu electrode is 22.5 nm,while the crystal size of the Ti/Pb O₂ electrode is 54.8nm.The electrochemical performance of Pb O₂ electrode is characterized by linear sweep voltammetry（LSV）and electrochemical impedance spectroscopy（EIS）.The LSV test results show that the Ti/Pb O₂-CTAB-Cu electrode has higher oxygen evolution potential and electrocatalytic activity.The EIS test results show that,compared with the unmodified Ti/Pb O₂electrode,the Ti/Pb O₂-CTAB-Cu electrode has the smallest charge transfer resistance and therefore has the highest electrocatalytic activity.The experimental results of hydroxyl radical generation ability test,electrode life and electrocatalytic degradation of Rhodamine B show that the Ti/Pb O₂-CTAB-Cu electrode has the highest hydroxyl radical generation ability,the longest service life and the most excellent electrocatalysis degradation of Rhodamine B effect.Using the prepared Ti/Pb O₂-CTAB-Cu electrode as the anode,the electrocatalytic oxidative degradation of Methylene Blue（MB）simulated printing and dyeing wastewater was carried out.First,the CV test results show that the indirect electrochemical oxidation reaction of MB on the Ti/Pb O₂-CTAB-Cu electrode surface mainly occurs.Then,the influence of MB initial concentration,current density,electrolyte concentration and initial p H value on MB removal rate,COD removal rate,degradation kinetics and current efficiency in the process of Ti/Pb O₂-CTAB-Cu electrode electrocatalytic oxidation degradation of MB.According to the experimental results,the relatively optimal degradation process parameters were selected:MB initial concentration was 30 mg/L,current density was 50 m A/cm²,Na₂SO₄ concentration was0.2 mol/L,and initial p H value was 3.After 120 minutes of degradation under this condition,the MB removal rate and COD removal rate were 100%and 81.5%,respectively.The process of electrocatalytic degradation of MB complies with the law of first-order reaction kinetics.The recyclability and safety of the Ti/Pb O₂-CTAB-Cu electrode were tested under the optimal degradation process conditions,and the main active substance for MB degradation by electrocatalytic oxidation was proved to be·OH by free radical trapping experiment.