Studies On Preparation Of Modifiedlead Dioxide Electrode And Treatment Of Nitrobenzene Wastewater

Because the electronic is added as reagent and there is no need to add other chemicals, electrochemical oxidation has the advantages of mild reaction conditions, simple reaction device, process flexibility, controllability and it has a stronger oxidizing ability than general chemical reaction. Electrochemical oxidation can process the poisonous and difficulty degradation organic wastewater. In the process of electrochemical oxidation, some crucial issues are related to the anodic materials, such as dynamics, electric energy consumption and the trial life of electrode. Therefore, the key issue is to choose the anodic material of good stability, good conductivity and high catalytic activity in the electrochemical industry.This paper uses new lead dioxide electrode containing nanotube interlayer made by anodic oxidation and electro deposition method and Ti/SnO2-Sb/PbO2electrode made by traditional method. These two kinds of different electrodes are investigated. The result indicates that the surface of lead dioxide electrodes is more compact, clearer and neater and the crystal particles are less. The interlayer of new electrodes facilitates the deposition on the surface of lead dioxide electrode. One conclusion can be made that new lead dioxide electrode is2.5V higher than traditional one on electric tension according to oxygen evolution polarization curve, so catalytic performance is improved. Also, the result of accelerating life test shows that life of new lead dioxide electrode is longer than traditional one and the stability of electrode is improved. Another conclusion can be drew that new lead dioxide electrode benefits the removal of nitrobenzene, and hence the degradation efficiency is higher on new lead dioxide electrode than that on traditional one from the experiment using nitrobenzene as target material to investigate catalytic performance of electrode.This paper uses new lead dioxide electrode to investigate the influence of initial pH value of solution、、electrolyte concentration and electrolysis time to degradation effect of nitrobenzene and TOC. In this experiment, the initial nitrobenzene concentration is100mg/L, the removal rate of nitrobenzene is96.73%and that of TOC is92.83%under the optimal conditions that current density of30mA/cm2, electrolytic dosage of0.1mol/L, pH value of7. The kinetic studies of effects on current density and electrolyte concentration to nitrobenzene degradation show that the relationship between-In (c(?)/c0) and degradation time t is linear, which indicates that the reaction of electrochemical degradation of nitrobenzene conforms to the laws of first-order kinetics.By studying the degradation pathway of nitrobenzene, it can be indicated that the process of chemical degradation of nitrobenzene in the reactor without the membrane is synergistic effect of cathode and anode. The degradation pathway of nitrobenzene can be divided into two parts. One part is that nitrobenzene is reduced to amino benzene on cathode, and then amino benzene is totally mineralized on anode. The other is that nitrobenzene is directly oxidized on anode. The experiment shows that the process of reduction of nitrobenzene to amino benzene on cathode and then oxidation of nitrobenzene on anode is the effective way to degrade nitrobenzene rapidly.