Treatment Of Aniline Simulated Wastewater By Three-Dimensional Electrode Method

In recent years,the problem of water pollution is geting more and more serious,and the high concentration of nitrogen-containing organic pollutants is difficult to remove by didegradation due to their strong biological toxicity for microorganisms.Three-dimensional(3d)electrocatalytic oxidation method has been applied for refractory wastewater treatment attributed to the characteristics of strong oxidative degradation ability,high treatment efficiency,without secondary pollution,improving the biodegradability of wastewater,and is commonly used to treat refrac.In this paper,the degradation of aniline,a typical nitrogen compound,by three-dimensional electro-catalytic oxidation,was investigated.The main work are as follows:(1)Effect of particle electrode on electro-catalytic degradation of aniline.Activated carbon,which is the most widely used particle electrode in 3d electrochemical system,was modified by loading TiO2-SnO2 on it with the impregnation method to get a GTSO.GAC and GTSO samples were characterized by SEM,EDX,FT-IR,XRD and BET,and used as the particle electrode of electrochemical system respectively.Results showed that titanium oxide crystal mainly located both on the surface and in the channel of GAC.The specific surface area of GTSO reduced 390.61 m2·g-1,the average pore diameter reduced 0.2623 nm,and total entrance reduced 0.00095 cm3·g-1 compared with GAC.The continuous experiments showed that both of the two kinds of activated carbon have very strong adsorption characteristics.The experiments lasted for 60 cycles with 2 h for a cycle until adsorption saturation of activated carbon could be achieved.By studying the effect of particle electrode,using GTSO as the electrochemical degradation of particle electrode on aniline removal rate was 85%,GAC as the particle electrode removal rate is 61%,the removal rate was higher than the two-dimensional electrode system with particle electrodes in 21%.In this paper,we finally determined the degradation of aniline wastewater by using GTSO as a 3d particle electrode.(2)Optimization of aniline degradation conditions by 3d electro-catalytic methode.The influencing factors such as electric field strength,electrolyte,pH and carbon/water ratio was investigated to find an optimum condition for aniline degradation.Experimental results showed that the aniline and COD removal rate could reach 84.5%and 60.3%under the condition of 1.2 V/cm voltage,0.03 mol/L Na2SO4 for electrolyte,pH 7,carbon water ratio 0.5,reaction time 120 min.(3)Electrochemical degradation pathway of aniline.Combined the determination of inorganic nitrogen(ammonia,nitrate,nitrite)in the system,detection of hydroxyl radical content and chemical composition analysis of electrolysis effluent by UV-Vis and GC-MS,technology,the pathway of electrochemical oxidation of aniline was ultimately proposed.Experimental results showed that after electrolysis,ammonia content increased to 27.70 mg/L,nitrate and nitrite increased to 2.30 mg/L and 0.15 mg/L,respectively,total nitrogen content decreased to 50.30 mg/L.This proved that aniline was degraded by electrolysis.Hydroxyl radicals inhibitors such as tert-butyl alcohol and ethanol-were added in the system for contrast experiments.Results showed that after electrolysis for 30 min,the removal rate of aniline for blank group is about 40%,while the aniline removal rate reduced to 20%after dosing tertiary butyl alcohol into the system.The determination of ·OH also found that when the electrolysis was 120 min,the absorbance of the effluent increased from 0 to 0.35.This indicated that after electrolysis,the hydroxyl radical is produced in the wastewater.UV-Vis and GC-MS analysis showed that the effluent contained quinones,phenols and carboxylic acids,and undecane were also observed.Thus,electrochemical degradation pathways of aniline was deduced in this work,guiding the further study of aniline.