| Bioelectrochemical system(BES),as a new kind of biological technology,is being paid more and more attention by researchers.Bio-electro-Fenton system,which is combining the BES and the Fenton method,the current generated by the anode can produce hydrogen peroxide at the cathode,thereby generating hydroxyl radical and degrading pollutants.In recent years,many researches have focused on the coupling of the electrochemical system with other processes.In this study,the treatment of dye wastewater through bio-electro-Fenton system was investigated.The preparation,filtering and optimization of the composite electrode,the conditions of the degradation of reactive brilliant blue KN-R,and the stability of the Fe-Mn/ACF composite electrode were studied.The main conclusions are as follows:(1)At the start of bio-electro-Fenton system,the anode potential gradually stabilized and finally reached-0.55 V after the domestication period of a month,so the domestication had been completed.(2)Through the comparison of degradation rate of reactive brilliant blue KN-R under different pH conditions,and yield of hydrogen peroxide under the same conditions with different composite electrodes,we found that the bio-electro-Fenton system equipped with Fe-Mn/ACF composite electrode was the best because of the degradation rate of reactive brilliant blue KN-R and the production of hydrogen peroxide was the largest.Therefore,we choosed the Fe-Mn/ACF composite electrode as the research object in subsequent experiments.(3)The Fe-Mn/ACF composite electrode was characterized by FT-IR,SEM,EDS.The results indicated that the quantity of oxygen-containing functional groups on the surface of carbon fiber increased after the oxidation treatment.After loading catalyst,the peak of carboxyl weakened,indicating the chemical reaction happened between catalyst and carboxyl groups,not only the physical loading.Manganese compounds could inhibit the size of iron compound particle.(4)The main electrochemical properties of the blank group and the reactor with Fe2O3/ACF and Fe-Mn/ACF composite electrode were respectively explored.The conclusions were as follows: through polarization curve and power density curve analysis,it was concluded that the reactor equipped with Fe-Mn/ACF composite electrode had better electrical performance;through electrochemical impedance spectroscopy analysis,it was concluded that the reactor equipped with Fe-Mn/ACF composite electrode had lower internal resistance so that it was beneficial to the reaction;in addition,through Tafel curve analysis,Fe-Mn/ACF composite electrode had higher catalytic activity.Therefore,the performance of Fe-Mn/ACF composite electrode was best,illustrating that adding appropriate manganese could greatly improve the system power density,as well as the utilization efficiency of electronic.(5)The Fe-Mn/ACF composite electrode was optimized before it was used in the biological Fenton system for the treatment of reactive brilliant blue KN-R.It turned out that when iron and manganese ion molar ratio and total ion concentration were 3:1 and 0.04 mol L-1 in the preparation process of Fe-Mn/ACF composite electrode,the degradation effect of reactive brilliant blue KN-R was best.In addition,the effect of initial pH and initial concentration on the degradation rate of reactive brilliant blue KN-R solution was studied.The conclusion was drawn that the optimum pH and initial concentration were 5 and 30 mg L-1,respectively.Finally,the reactor with Fe-Mn/ACF composite electrode could proceed twelve batches of circulatory discontinuous degradation of reactive brilliant blue KN-R experiments.We found that when the twelfth batches was finished,the degradation rate could still be maintained at 81.1%.Therefore,the system has good stability and good application prospect. |
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