Ti/RuO_2-ZrO_2-SnO_2电极的研制及处理有机废水的研究

Preparation of Ti/RuO_2-ZrO_2-SnO_2 electrode and treatment of organic sewage

通过涂覆热分解法制备了Ti/RuO_2-ZrO_2-SnO_2、Ti/RuO_2电极材料,采用X射线衍射(XRD)、扫描电镜(SEM)和循环伏安(CV)对电极材料进行表征,考察了电流密度、Na Cl质量浓度、p H值及电极间距对废水COD降解率的影响。结果表明,Ti/RuO_2-ZrO_2-SnO_2电极对COD具有更高的降解率,对其进行工艺优化。电极材料对废水降解的最佳工艺条件为电流密度40 m A/cm2,Na Cl质量浓度4 g/L,p H=5. 0,电极间距10 mm,COD的降解率达到90. 5%。Ti/RuO_2-ZrO_2-SnO_2电极中SnO_2与RuO_2生成固溶体,有利于增强涂层与基体之间的结合力,提高电极的稳定性; ZrO_2起到细化晶粒的作用,致使电极表面粗糙度增加,增强了电极的电催化性能,且降解过程符合一级动力学模型。

The paper intends to introduce a novel approach to preparing Ti/RuO2-SnO2-ZrO2 and Ti/RuO2 electrodes at the high temperature of 450℃via the thermal decomposition method,in which titanium plate has been used as the support and isopropyl alcohol with RuCl3·nH2O,SnCl4·5H2O and ZrO(NO3)2 and that with RuCl3·nH2O only as the masking liquid,respectively.The electrodes have been characterized by a number of approaches,including the scanning electron microscope(SEM),the X-ray diffractometer(XRD)and the cyclic voltammetry(CV).Then,the above mentioned methods have been further adopted for degrading the chemical oxygen demand(COD)in the sewage purification.The corresponding results of the above mentioned experiments and researches demonstrate that the degrading rate of COD in the case for Ti/RuO2-SnO2-ZrO2 tends to be higher than that in the condition of Ti/RuO2.Furthermore,we have also investigated the effects of the current density,the NaCl concentration,the pH value and the electrode spacing distribution through a series of single-factor and orthogonal tests in detail.The afforementioned analyses indicate that the said single-factor and orthogonal tests tend to produce their main effects for degrading the COD in the sewage by using Ti/RuO2-SnO2-ZrO2,the pH value and the degradation rate of COD in it at a high rate of 90.5%under the the optimum condition for degradation,that is to say,the current density of 40 mA/cm^2,the concentration of NaCl of 4 g/L,pH value of 5.0 with the electrode spacing of 10 mm.Besides,the characterization results also disclose that the formation of the solid solution of SnO2 and RuO2 in the Ti/RuO2-ZrO2-SnO2 electrode proves to be beneficial for enhancing the bonding between coating and substrate.Besides,it can also help to improve the stability of the electrode,for ZrO2 can refine the grain size,increase the surface roughness of the electrode and further enhance the electro-catalytic performance.In addition,the experimental data of the COD degradation has been found fitted by the pseudo-first-order model,and the reaction kinetic of COD degradation in the sewage in the condition of Ti/RuO2-SnO2-ZrO2 tends to be well in accord with the model prediction.