Preparation Of Modified PbO₂ Electrodes And Its Application In Electrochemical Degradation Of Phenol Wastewater

With the technology progress and industrial development,large number of pollutants into the environment.Therefore,Environment pollutants removal has become a major problem for the sustainable development of modern industry.Electrochemical oxidation process has received the widespread attention due to the strong oxidation.Recently,how to enhance the catalytic performance of the electrode and improve the ability of degradation is the main research in researchers.PbO2 electrode was used in a large number of applications in electrochemical oxidation process due to high oxygen evolution potential,strong corrosion resistance,low price advantages.In order to enhance the catalytic performance and stability,a novel modified ?-PbO2 electrode was prepared by electro-deposition method and investigated for degradation of aromatic hydrocarbons in aqueous solution.The SnO2-Sb interlayer was prepared on the Ti plant by thermal deposition.And the ?-PbO2 active layer was coating by electrochemical deposition.The graphite oxide was used to modify the PbO2 electrode.The PbO2 electrode was prepared by different concentration of the graphite oxide in solution(0.5g·L-1,0.8g·L-1,1.0g·L-1,1.5g·L-1)of electrochemical deposition.We compared the different electrodes to investigated the effects of graphite oxide on the electrode.The surface morphology and structure of the ?-PbO2 electrodes were analyzed by field-emission scanning electron microscopy(FE-SEM)and X-ray diffraction(XRD).The results show that the electrode outer layers are coated by quadrangular ?-PbO2 crystals.This GO-doped could make coating more uniform and compact.Electrochemical measurements including cyclic voltammetry(CV)and kinetic analysis of the oxygen evolution reaction(OER).The graphite oxide obviously increases the oxygen evolution potential(OEP),improve the electron transfer rate and reduce the energy loss.The oxygen evolution potential of PbO2-GO(1.0)electrode was improved to 1.997 V.The Tafel slop and exchange current density are 0.54686 V and 2.70×10-6 A·cm-2,respectively.The performance of electrochemical oxidation was evaluation by using the modified PbO2 electrodes degradation in 100 mg L 1 phenol simulated wastewater.It was studied that the degradation efficiency and kinetics in the electrochemical oxidation process.The Electrochemical degradation tests were prepared with conventional three-electrode cell system.The degradation time is 120 min.The phenol concentrations were measured by 4-aminoantipyrine spectrophotometric method.It was explored that the doping amount,current density,plate distance,initial concentration of phenol,electrolyte concentration and the electrolytic time.During the process of the phenol degradation,the PbO2-GO(1.0)electrode showed the best performance.And the better degradation conditions were current density of 30 mA·cm-2,plate distance of 1 cm,electrolyte concentration of 0.1mol·L-1 and phenol initial concentration of 100mg·L-1.The removal efficiency is 91%in 120 min.The phenol removal reaction was found to fit the pseudo first-order kinetics.The PEI and graphite oxide were doped into PbO2 electrodes.The surface morphology and structure of the ?-PbO2 electrodes were analyzed by field-emission scanning electron microscopy(FE-SEM)and X-ray diffraction(XRD).It was showed that the coating of PbO2 was more smooth and compact.The number of pores and cracks were decreased.It was more stable than the PbO2-GO electrode.The anti-corrosion performance of the electrodes was investigated using accelerate lifetime test.It was showed that the electrode was longer lifetime when the PEI was doped.In order to evaluate the safety performance of the PbO2 electrode in the degradation process,the concentration of Pb element dissolved in electrolyte was analyzed by Inductively coupled plasma mass spectrometry.We found that the concentration of Pb element was reduced after the PEI added.The oxygen evolution potential of electrodes with PEI is not too much effects compared with unmodified-PbO2 electrodes by cyclic voltammograms.Moreover,the degradation efficiency was a small improved.