Preparation Of PbO₂Electrode With High Performance And Its Application

As a green oxidation technology, electrochemical oxidation technology has beenwidely used for pretreatment of toxic refractory waste water. PbO₂electrode is a cheapand insoluble anode, and is always chosen as an anode in electrochemical oxidation oforganic. According to the research status of PbO₂electrode, we have have made someexploratory research on the preparation of PbO₂electrode with with high performance.In chapter3, the acid dyeing chemical wastewater was pretreated byelectrochemical oxidation method on PTFE-modified PbO₂electrode. The resultsshowed that COD removal rate reached43.4%and BOD/COD increased from0.034to0.14under the following conditions: supporting electrolyte:2g·L^-1sodium chloride,pH=0.85, current density:30mA·cm^-2, electrolysis time:20minutes. AtAt the same costfor per ton wastewater, catalytic catalytic ozonation could get a COD removal rate of27.7%and also enhanced BOD/COD from0.034to0.12. However, considering theconvenience of operation and equipmentequipment investment, electrochemicaloxidation method is better than ozonation. Therefor, preparation of PbO₂with highperformance is very important for application of electrochemical oxidation method inpretreatment of toxic refractory wastewater.In chapter4, a new plating solution （sulfamic acid bath） for preparation of PbO₂electrode was put forward. The results showed that the surface of the PbO₂electrodeprepared in sulfamic acid （Ti/PTFE-F-PbO₂-Ⅰ） was highly refined grains and moremeticulous, and that its crystal was still β-PbO₂. The Ti/PTFE-F-PbO₂-Ⅰelectrode hadhigher overpotential for oxygen evolution in Na₂SO₄solution than Ti/PTFE-F-PbO₂-Ⅱelectrode. Due to this property, the Ti/PTFE-F-PbO₂-Ⅰ might improve current efficiency during electrochemical oxidation of organic. The electrolysis test in9mol·L^-1H₂SO₄showed that the accelerated life of the Ti/PTFE-F-PbO₂-Ⅰ e lectrodereached1160h, suggesting that its service life under conventional conditions was estimated tobe6.64years. That might associated with surface structure which has highly refinedgrains and meticulous. The more compactness of surface of the electrode couldeffectively effectively stop active oxygen to titanium substrate migration, and make theelectrode more stable. Electrochemical degradation of para-chlorophenol on twoelectrodes showed that the Ti/PTFE-F-PbO₂-Ⅰelectrode had higher efficiencies in C/C0than the Ti/PTFE-F-PbO₂-Ⅱ electrode by10%. The optimized conditions forpreparation of Ti/PTFE-F-PbO₂-Ⅰwas: current density:0.06A·cm^-2; temperature:40℃;stir speed:1300r·cm^-2; time of electrodeposition:1h.In chapter5, a nano-TiO₂modified Ti/PTFE-F-PbO₂-Ⅰwas prepared and itselectrochemical performance was also investigated. The results showed that thenano-TiO₂modified Ti/PTFE-F-PbO₂-Ⅰhad higher overpotential, larger larger Tafelslope and exchange current density (3.41×10^-5A·cm^-2) for oxygen evolution in a2g·L^-1Na2SO4solution than the Ti/PTFE-F-PbO₂-Ⅰ. Electrochemical degradation ofpara-chlorophenol on the the two electrodes showed that the nano-TiO₂modifiedTi/PTFE-F-PbO₂-Ⅰelectrode had higher efficiencies in C/C0than the Ti/PTFE-F-PbO₂-Ⅰelectrode.