Three-dimensional Electrode Electrocatalytic Degradation Of Methyl Orange Simulated Wastewater

China is a large country in terms of printing and dyeing wastewater.Azo dyes are widely used in the production process of textiles,fibers,cotton and related materials because of their rapid synthesis and easy coloring.The generally discharged printing and dyeing wastewater contains complex substances,which are highly colored and generally difficult to decompose.The effect of some traditional methods for treating azo wastewater is not significant.Currently,electrocatalytic oxidation technology,as an advanced treatment technology,has the advantages of significant treatment effect,strong adaptability,low pollution and easy operation and management.Therefore,it has been frequently mentioned and used in recent studies.In this thesis,the electrode of Sn O2-loaded alumina particles was prepared by impregnation roasting method,and the optimal preparation conditions of the particles under four influencing factors of impregnation time,impregnation concentration as well as roasting temperature and roasting time were investigated.Through a set of four factors and three levels of orthogonal experiments,it was concluded that the order of each factor affecting the particle performance was: roasting time > impregnation time > other two factors,and the catalytic performance of the electrode increased with the increase of roasting time,decreased with the increase of impregnation concentration and impregnation time,and increased and then decreased with the increase of roasting temperature.And an optimal set of preparation conditions was found: dip concentration 0.1 mol/L,impregnation time 12 h,roasting time 6h,and roasting temperature 550°C.The dye removal rate under this condition was about 76.55%and COD removal rate was 55.27%.It indicates that the prepared particle electrode has good electrocatalytic performance and is well reused.The experiments were carried out to degrade methyl orange simulated wastewater in a homemade reactor.The effect of each factor on the degradation rate of methyl orange was investigated by conducting single-factor experiments on five influencing factors: electrolysis time,electrolysis voltage,electrolyte dosage,p H value and aeration amount.It can be concluded that the degradation efficiency of the system no longer changed when the electrolysis time reached 60 min.The degradation rate increased and then decreased with the voltage,and reached the extreme value at 6V.The degradation rate increased and then decreased with the increase of electrolyte dosage,and reached the extreme value at 1g/L.The degradation rate increased and then decreased with the increase of p H,and reached the extreme value at p H=7.2.The degradation rate increased and then decreased with the increase of aeration,and reached the extreme value at 200 m L/min.When the concentration of methyl orange simulated wastewater was 100 mg/L,under the conditions of electrolysis time of 60 min,electrolysis voltage of 6 V,p H=7.2,electrolyte dosage of 1 g/L,particle electrode dosage of 120 g,and aeration rate of 200 m L/min,the removal rate of methyl orange and COD could reach the highest value respectively,and the removal rate of methyl orange was 82.27%,and the removal rate of COD was 61.77%.After the optimization analysis using response surface method,it can be concluded that the interaction effect of electrolysis voltage and p H has a greater effect,and the electrolyte dosage has the least effect.The contour plot and 3D surface plot between the factors showed that the effect of electrolysis voltage and electrolyte concentration on COD removal was slightly greater than that of methyl orange removal when the p H value was fixed.When the electrolyte dosage was fixed,the effect of electrolytic voltage and p H on the removal of methyl orange was slightly greater than that of COD.When the voltage was fixed,the interaction between electrolyte dosage and p H was relatively small,and the effect on the removal rate of methyl orange was not much different from that of COD.The predicted values of methyl orange removal rate were 82.63% and COD removal rate were 61.78% when the electrolysis voltage was 5.86 v,electrolyte dosage was 0.97g/L and p H was 6.94.The difference between the actual and predicted values was small,indicating that the system had good degradation performance.