Study On The Performance Of Amaranth Dye Wastewater By Electrochemical Advanced Oxidation Processes

China is an advanced country in the textile printing and dyeing industry,and more than 10%of the total industrial wastewater was discharged by the printing and dyeing industry which caused serious pollution to the aquatic environment.Recently,for the treatment of such refractory organic pollutant wastewater,electrochemical advanced oxidation processes(EAOPs)based on strong oxidizing substances such as·OH have attracted much attention,including anode electrocatalytic oxidation and cathode electro Fenton processes.At present,the performance of electrode materials is the main challenge that restricts the development of EAOPs.Therefore,the preparation of electrode materials was mainly investigated in this paper,including titanium-based SnO2 anodes and graphite felt cathodes;then the electrodes was used for amaranth dye(AMR)simulation wastewater.The optimal treatment conditions were analyzed by response surface(RSM)methodology of wastewater degradation treatment in this research,on this basis,the degradation mechanism of AMR simulated wastewater was investigated.First of all,starting from the modification methods of electrolyte additive modification,intermediate layer introduction,element doping,the TiO2NTs/SnO2-Sb electrode introduced into the intermediate layer of titanium dioxide nanotubes(TiO2NTs)was selected and the optimal conditions was obtained through orthogonal experiments.Scanning electron microscope(SEM),X-ray diffraction(XRD)and other methods were used to characterize and analyze the surface morphology;electrochemical analysis showed that the electrocatalytic activity was significantly improved.The effect of different process parameters on the treatment of AMR simulated wastewater by anode electrocatalytic oxidation was investigated,and the results showed that the removal efficiency of color(RC)of AMR increased with the increasing of current density and the concentration of electrolyte Na2SO4,and had better performance in the neutral pH range.In addition,the degradation of AMR basically conformed to the first-order reaction kinetics equation.And the RC would have decreased by a rise in the initial concentration of AMR.Secondly,graphite-phase carbonitride(g-C3N4)was used as the nitrogen source,and carbon black was used to modify the graphite felt(GF)cathode material.Under the best preparation conditions,the successful embedding of N element was confirmed by XPS test,and electrochemical test analysis showed strong electrocatalytic activity.The effect of different process parameters on the treatment of AMR simulated wastewater by the electro Fenton system was investigated,and the results showed that lower current density and Fe2+concentration showed a better effect on the degradation of AMR,and pH was more favorable under acidic conditions.Compared with the electrocatalytic oxidation treatment alone,when the initial concentration of AMR was increased from 50 mg/L to 200 mg/L,RC could also reach 95%.Then,the process parameters of electrocatalytic oxidation and electro Fenton treatment of amaranth red dye wastewater were designed and optimized through RSM.As we can see form the result that the Rc of AMR reached 96.23%for the response surface research of electrocatalytic oxidation treatment of AMR wastewater under the optimal treatment conditions,and it was found that the phytotoxicity of the AMR dye simulated wastewater was reduced through the phytotoxicity test,hence there is potential to promote the reuse of wastewater.For the response surface study of AMR wastewater treatment by electro Fenton,the RC of AMR reached 96.98%under the best treatment conditions;the RC of AMR only decreased by about 8%after 10 times of repeated uses of the modified cathode,showing a stable potential application performance.Finally,the research on the mechanism and pathway of AMR degradation reaction showed that the system mainly indirectly oxidizes AMR with strong oxidizing substances such as ·OH in the system.First,the azo bond was broken,and then the amine group(-NH2)and sulfonic acid group(—SO3-)were eliminated and substituted on the naphthalene ring structure.Being further removed of the carboxyl group,the ring-opening degradation of phenolic derivatives formed small molecular organic acids,and they could be degraded into CO2 and H2O eventually.