【作者】 张力；

【导师】 梁镇海；

【作者基本信息】 太原理工大学 ， 化学工程， 2015， 硕士

【摘要】 在废水处理技术中，电化学水处理技术具有“环境友好技术”之称，广受人们关注。本论文选用了金属铌作为电极基体，制备了铌基二氧化铅电极，并通过掺杂氧化物的方法对其进行改性，研究了铌基二氧化铅电极的电化学性能和对染料废水的降解效果，为染料废水处理中电极材料的选择提供了实验基础。通过电沉积的方法制备了Nb/PbO2电极，并利用掺杂方式进行改性，制备出Nb/ZrO2+PbO2电极。利用扫描电镜（SEM）、X射线衍射（XRD）和循环伏安曲线分析Nb/PbO2电极表面形貌、组成和催化性能;；探究了不同Na2SO4浓度、反应温度、pH值和电流密度对该电极降解甲基橙（MO）模拟废水效率的影响；用线性伏安、电化学交流阻抗、循环伏安曲线对比分析掺杂前后电极的电化学性能和对MO催化活性。结果表面，Nb/PbO2电极表面致密、均匀且呈蘑菇云状，这种结构使电极活性层与基体结合紧密，不易脱落，且比表面积较大；电极表面物相主要由β-PbO2和少部分的α-PbO2组成；循环伏安曲线显示了Nb/PbO2电极降解甲基橙（MO）的可能性，电极对MO的催化活性较高；电极降解MO最佳的操作条件pH为6，温度为45oC，电流密度50mA·cm-2，0.08mol·L-1Na2SO4。在此条件下降解30min后，MO降解率和溶液COD去除率分别达到99.6%和72.6%；对不同初始浓度MO的去除率与降解时间关系进行线性拟合，分析得出Nb/PbO2电极上MO的降解速率与其初始浓度的关系方程。MO在Nb/PbO2电极上的降解过程符合一级动力学反应过程。ZrO2掺杂使Nb/PbO2电极表面更致密、粗糙，结晶尺寸变小，增大了电极的比表面积，提高了电极的催化活性；Nb/ZrO2+PbO2电极活性层主要由β-PbO2和少量的α-PbO2以及部分ZrO2共沉积而成；电极的析氧过电位更高（2.03V），吸附电容更小，电荷转移电阻更大，能减小溶液中氧释放和功率损耗，使更多的OH·活性分子与有机物发生反应，提高了甲基橙(MO)有机物的降解效率（99.9%）和COD去除效率（79.5%）。Nb/ZrO2+PbO2电极的MO电催化活性更佳（3.22.mA）,其氧化电催化反应受扩散控制。更多还原

【Abstract】 In the wastewater treatment technology, the electrochemical asenvironmentally friendly technology has widely attention. In this paper, metalniobium is used as the electrode substrate to prepare Nb/PbO2that wasmodified by the method of oxide doped. In addition, electrochemicalperformance and the effect on the degradation of dye wastewater were studied,which provided the important basis for the optimization of electrode materials indye wastewate degradation.Nb/PbO2electrode and ZrO2-doped Nb/PbO2electrode were prepared byelectrodeposition and used as an anode for the electrochemical degradation ofmethyl orange (MO). The microstructure and electrochemical properties ofNb/PbO2electrode were investigated using scanning electron microscopy (SEM),X-ray diffraction (XRD), cyclic voltammograms. The effects of electrolyte,temperature, current density, and pH on decolourisation efficiency were alsostudied. The comparison of two kinds of electrode were investigated usinglinear-sweep voltammetry, electrochemical impedance spectroscopy and cyclicvoltammograms. Results revealed that the Nb/PbO2electrode surface is dense, uniform andmainly composed of β-PbO2with a small amount of α-PbO2, as well as it hasgood catalytic effect on degradation of methyl orange; at initial pH6.0,45oCtemperature,50mA·cm2current density,0.08mol·L1electrolyte (Na2SO4)concentration, and30min electrolysis time, the colour removal efficiency andCOD removal reached99.6%and72.6%, respectively. The reaction mechanismof electrocatalytic MO degradation by Nb/PbO2electrode mainly involved theOH radical attack of parent molecules, and the degradation followedpseudo-first-order kinetics.ZrO2-doped Nb/PbO2electrode has a dense and rough surface and a smallsize crystal particles. Nb/ZrO2+PbO2electrode surface is mainly composed ofβ-PbO2with a small amount of α-PbO2and ZrO2.Electrochemical performancetests show that Nb/ZrO2+PbO2electrode has higher oxygen-evolution potential（2.03V）and lower charge-transfer resistance, as well as higher electrocatalyticactivity（3.22mA）in the degradation of organic materials than Nb/PbO2. Thecolour and COD removal efficiency was up to92.3%and79.5%, respectively.Electrocatalytic MO degradation processes by Nb/ZrO2+PbO2are irreversibleand controlled by diffusion.更多还原