Study On Preparation Of SnO₂ Electrode And Application To Organic Wastewater Treatment

With the development of industry,the amount of organic wastewater is increasing gradually.The compounds in organic wastewater with wide sources and stable structure have caused serious harm to the ecological environment and life.At present,the treatment methods of organic wastewater mainly include adsorption,membrane separation,biochemical treatment and advanced oxidation method.But the traditional treatment methods are easy to produce secondary pollution,high treatment cost,limited operating conditions and other problems.Therefore,it is of great significance to develop an efficient,environmentally friendly and economical water treatment technology.Electrochemical catalytic oxidation technology has the advantages of high treatment efficiency,environmental friendliness,less limited by operating conditions and high degree of automation,which can realize the efficient treatment of organic wastewater.Electrode material is the core of electrochemical catalytic oxidation technology,tin dioxide electrode with good catalytic effect,environmental protection,low energy consumption,is a very promising catalytic material in the field of electrocatalysis,but its service life is short,which severely restricts their practical application in industrial field.In this paper,a modified tin dioxide electrode（Ti/SnO₂-ESIX）was prepared by thermal decomposition method,which greatly improved the service life of the tin dioxide electrode.Then the performance of the electrode was studied by various characterization methods.First,Modified tin dioxide electrodes with different tin salt mass were prepared by thermal decomposition method.The accelerated life test of the electrodes with different tin salt content was carried out.The surface morphology,crystal structure and electrochemical performance of the electrode with the best tin salt usage that we call it Ti/SnO₂-ESIX were characterized by XRD,SEM,ALT,LSV,EIS and CV.Then,the degradation effect of Ti/SnO₂-ESIX on concentrated water of secondary reverse osmosis was also investigated.The results show that when the mass of tin salt is 0.51 mg·cm^-2,the maximum accelerated life of the electrode reaches 52.5 h.The modified tin dioxide electrode has a tetragonal rutile structure,and the active oxide layer of the electrode is composed of multilayer nanometer particles,which has a compact and compact structure.This structure improves the stability of the active oxide layer and increases the active site.The results of XRD and SEM images before and after the accelerated life show that the main reason for electrode deactivation is the formation of the inert layer with low activity,which reduces the conductivity and leads to the increase of voltage,the oxide layer falling off,and accelerated electrode deactivation.The electrochemical characterization results show that the life of the modified Ti/SnO₂-ESIX electrode is improved,the electrical conductivity of the electrode is better,and the electrode impedance is smaller.The electrolytic catalytic results show that the COD value of the secondary reverse osmosis water can be effectively removed at the current density of 30m A·cm^-2,which indicates that the electrode has a good catalytic effect.Secondly,in order to further analyze the effects of different parameters on Ti/SnO₂-ESIX electrode degradation of organic,different contents of phenol and aniline solution were simulated in laboratory conditions,and the effects of current density,electrolyte concentration,initial concentration and pH value on the catalytic effect of Ti/SnO₂-ESIX electrode were investigated.The results show that the catalytic effect is enhanced with the increase of current density.The increase of chloride ion content is beneficial to degradation reaction.However,the degradation efficiency did not increase when the electrolyte concentration to 1000 mg·L^-1.The effect of pH value on degradation was not obvious.The current efficiency decreases as the reaction proceeds;decreases with the increase of current density and increases with the increase of initial concentration.In the first 30 min of the reaction,the degradation rate is fast,the current efficiency is high,and more than 60%COD can be removed,indicating that the electrode has a good mineralization effect on phenol and aniline.Ti/SnO₂-ESIX electrode has good electrocatalytic performance and high service life,which can effectively mineralize organic matter under conventional operating conditions.The high service life can ensure the long-term and stable operation in the electrode industry,and is expected to obtain better application in the industry.