Study On Preparation Of Modified Ti/RuO₂-IrO₂ And Ammonia Nitrogen Degradation In Wastewater

Ammonia nitrogen wastewater in production and life has a wide range of sources,improper disposal will cause harm to the ecological environment and human life.Then electrochemical oxidation technology,an economic,efficient and green treatment technology,can be competent for the treatment of all kinds of ammonia nitrogen wastewater,and anode material as its core has been widely concerned.This study is devoted to the modification of traditional Ti/RuO₂-IrO₂,aiming to obtain the anode material with low cost and relatively good comprehensive performance,which will be used to treat ammonia nitrogen wastewater.The specific research and results are as follows:（1）Ti/RuO₂-IrO₂ was prepared by brushing method.When the mass fraction of polyethylene glycol in the coating solution was 10%(ω_（PEG）=10%),the coating surface was uniformly dense and RuO₂-IrO₂ solid solution was formed.The average size of the coating crystal was 23.7 nm,and the chlorine evolution potential of the electrode was1.0969 V.The accelerated life was as high as 93.63 h,but its potential window was small and the production cost was high.（2）Ti/RuO₂-IrO₂ was prepared by impregnation method,and the preparation parameters were optimized.Withω_（PEG）=20%,n_（Ru:Ir）=5.5:1,T=500℃,and ultrasonic to assist,the coating surface was uniform and dense with honeycomb structure,and the average crystal size was 34.1 nm.The chlorine evolution potential was 1.1097 V,and the accelerated life was 32.98 h,which was only about 2/5 of the accelerated life of the electrode prepared by brushing method.Although the comprehensive performance of the electrode was decreased,the amount of coating solution was about 1/6 of the former,and the preparation cost was reduced about 80%.（3）Ti/RuO₂-IrO₂-SnO₂-CeO₂ was prepared by doping Sn and Ce.With n_{（Ru:Ir:Sn）}=5.5:1:3.9 andω_（Ce）=4%,the overall performance of the electrode was better.The coating has RuO₂-IrO₂-SnO₂ solid solution and the coating crystal was refined with an average size of 22.5 nm.The potential of chlorine evolution was 1.0973 V,and the potential window increased.The accelerated life is 34.25 h.The good electrocatalytic activity could be maintained by doping of Sn and Ce,and the amount of Ru and Ir was reduced by nearly 50%,which further reduced the cost.（4）Compared with the superior performance of self-made electrodes,the commercial electrode had some problems,such as thin electrode coating,poor uniformity and density,high chlorine evolution potential and short electrode life.The chlorine evolution potential was 1.1221 V and the accelerated life was only 18.35 h.（5）Ti/RuO₂-IrO₂-SnO₂-CeO₂ was selected for the treatment of degradation of ammonia nitrogen wastewater containing chloride,and the optimal conditions were selected by response surface method:the current density was 0.05 A·cm^-2,the initial Cl^-concentration was 5000 mg·L^-1,and the p H was 9.00.Under these conditions,the removal rates of NH₃-N and TN could reach 100%,and removal of NH₃-N under the optimal conditions accorded with zero-order kinetics by time.The kinetic equation was C_t=-1.6505t+87.172,and R²=0.9859.