Electrochemical Oxidation Degradation of Methyl Orange Wastewater by Nb/PbO2 Electrode

Nb/PbO2 electrode was prepared through electrodeposition method and used as anode in the reaction of electrochemical degradation of methyl orange (MO). The SEM, XRD and cyclic voltammetry tests showed that Nb/PbO2 electrode surface was dense, uniform and mainly composed of ß-PbO2 with a small amount of α-PbO2, as well as it has good catalytic effect on degradation of MO. The effects of supporting electrolyte, degradation temperature, current density and pH value on the decolourisation efficiency of MO had also been studied. Results revealed that at initial pH=6.0, 45 oC temperature, 50 mA'cm-2 current density, 0.08 mol-L-1 electrolyte (Na2SO4) concentration, and 30 min electrolysis time, the colour removal efficiency and COD removal reached 99.6% and 72.6%, respectively. The reaction mechanism of electrocatalytic MO degradation by Nb/PbO2 electrode mainly involved the OH radical attack of parent molecules, and the degradation followed pseudo-first-order kinetics.