Preparation And Decolorization Properties Of Three-dimensional Electrode Material

Advanced electrochemical oxidation process, playing a dominating role in treatment of degradation-resistant wastewater, is the most promising method. thereinto, electrochemical oxidation technology and electrical Fenton widely attracts the concentration of many researchers. Electrode material stands a critical position in the electrochemical oxidation process, and its performance will directly determine the effect of electrochemical oxidation technology. Three-dimensional foam owns the large specific surface area, the high porosity,which can effectively improve the mass transfer efficiency of particles and increase the contact surface to optimize performance of the electrode reaction. Thus, it has important significance on three-dimensional foam-electrode matrix research.In this paper,three-dimensional macroporous PbO2 electrode and three-dimensional TiN-PbO2 electrode were prepared by electrodeposition method with CNT sponge base. It was found that three-dimensional PbO2 electrode surface presents the uniform distribution of pyramid (3-type PbO2 particles. The decolorization of methylene blue test showed that three-dimensional PbO2 electrode has good electro-catalytic activity, and the methylene blue decolorization efficiency is 90.4%, while the decolorization rate is 68.8% on flat PbO2 electrode under the same conditions. Three-dimensional PbO2 electrode was modified by means of adding the nano-TiN. When the concentration of added TiN is 4mmol L-1 the electrode has the best dye decolorization efficiency of 96.6%, which is 6.86% more than that on the control one.Three-dimensional CNT electrode was prepared by the electrophoretic method with foam nickel as the substrate, and was selected as the cathode material for the electro-Fenton system. Subsequently, manganese dioxide and polyaniline were selected to modify the three-dimensional CNT electrode, and three-dimensional CNT-MnO2 and CNT-PANI composite electrode was prepared by using direct current deposition method. Effects of the deposition time, deposition current density, and deposition temperature on the ability of in-situ H2O2 production were studied to optimize the conditions for the preparation of composite electrodes. Three-dimensional CNT-MnO2 and CNT-PANI electrodes were used as cathodes to construct the electro-Fenton system, and methylene blue was selected as the target agent. The operation conditions of electro-Fenton system were optimized through investigating the initial concentration of Fe2+, dye concentration, pH, current density, the amount of aeration and so on, the result shows that the optimized operation conditions of three-dimensional CNT-MnO2 in the electric-Fenton system are: current density of 15mA cm-2,pH=2, aeration rate of 1.0 L min-1, and the solution Fe2+ concentration of 5mmol L-1. Under the condition, the decolorization rate is 96.8%. When the initial concentration of Fe2+ is lmmol L'1, three-dimensional CNT-PANI composite electrode in electro-Fenton process has the best decolorization effect, and the efficiency is 99.1%, which is slightly higher than that of three-dimensional CNT-MnO2 composite electrode.