Modified Lead Dioxide Electrode And Its Application In Industrial Wastewater Treatment

Electrocatalytic oxidation technology is widely used in sewage treatment.As an ideal material of electrocatalytic oxidation technology,lead dioxide（PbO₂）electrode has good stability and electrochemical activity,often modified to improve the practical application value of PbO₂ electrode.Polyvinylidene fluoride lead dioxide zirconia composite electrode（PVDF-PbO₂-ZrO₂）and alkylphenol polyoxyethylene ether reduced graphene oxide lead dioxide electrode（P-r GO-PbO₂）were prepared.The prepared electrode was used to degrade pollutants and actual industrial wastewater,and the electrocatalytic performance of the electrode was evaluated.PVDF-PbO₂-ZrO₂ composite electrode was prepared by electrodeposition of polyvinylidene fluoride（PVDF）and zirconia（ZrO₂）,Which has dense structure and superhydrophobic surface（water contact angle is 156.5°）.Steady state polarization curve（LSV）and electrochemical impedance（EIS）show that the electrode has high oxygen evolution potential（OEP）（1.63 V vs.SCE）and smaller charge transfer resistance.In the electrocatalytic degradation of paracetamol（APAP）,the removal rate of APAP by the electrode is 98.24%after 100 min,and the energy consumption is only 20.09 k Wh·m^-3,indicating that the electrode has stronger ability of catalytic degradation of pollutants and less energy consumption.The degradation pathways of APAP were studied by gas chromatography-mass spectrometry（GC-MS）,mainly including phenol hydroxyl carboxylation,C-N bond breaking and benzene ring opening.An industrial oily wastewater is used to test the practical application value of the electrode.The results show that after degradation for 120 minutes,the COD removal rate of oily wastewater can reach 83.33%,and the oil content can be reduced from 148 ppm to 4 ppm.It is proved that the PVDF-PbO₂-ZrO₂ electrode has good practical application value.The PbO₂ electrode modified by reduced graphene oxide（r GO）and surfactant OP-10（P-r GO-PbO₂）was prepared by electrodeposition,it was found that the addition of r GO helped to reduce the crystal particle size of PbO₂.At the same time,the electrode has high oxygen evolution potential（OEP）（2 V vs.SCE）and good strengthening life（72 h）.The presence of C-πelectrons in r GO makes r GO form a strong Lewis base,which greatly enhances the electrocatalytic performance of P-r GO-PbO₂ electrode,the electrode has good electrocatalytic effect.The electrode was used for electrocatalytic degradation of acrylamide（AA）.The optimum degradation conditions were as follows:the current density was 0.06 A·cm^-2,the concentration of Na₂SO₄ was 0.15 mol·L^-1,and the initial p H value was 7.The actual dye wastewater of a printing and dyeing factory in Tianjin was treated with P-r GO-PbO₂ electrode.After 120 min,the COD removal rate of dye wastewater can reach 89%,Which is proved that P-r GO-PbO₂ electrode has a good industrial application prospect.The degradation mechanism of AA was discussed by gas chromatography-mass spectrometry（GC-MS）,and the possible degradation ways were put forward.The degradation process mainly involves the indirect oxidation of hydroxyl（·OH）.AA is oxidized into a series of intermediate products with amide,cyano and carboxyl groups,and finally oxidized into CO₂,H₂O,nitrate and N₂.