Study On The Mechanism And Promotion Method Of Floating Cathode Electro-Fenton Process For Treatment Of Benzene-Containing Wastewater

Benzene is a very representative hydrocarbon substance,and it is a kind of BTEX.It has the characteristics of wide source and strong harm to the environment and human health.It has been listed as 120 class 1 carcinogens by the International Agency for Research on Cancer of the World Health Organization.The existing treatment methods of benzene-containing wastewater mainly include adsorption method,biodegradation method,extraction method,etc.However,these traditional treatment methods have shortcomings such as poor reproducibility of adsorbent materials,low treatment efficiency,serious secondary pollution,and complicated operation.Therefore,it is urgent to develop a cost-effective and no secondary pollution treatment method for benzene-containing wastewater.Electro-Fenton technology is an advanced oxidation technology developed in recent years.It has the advantages of high processing efficiency,fast speed,and easy control of response.It has been widely used in the field of environmental treatment.However,the research on the treatment of benzene-containing wastewater by electro-Fenton technology is rarely mentioned.And the internal reaction of the electro-Fenton system is complex,and a variety of oxidative substances coexist.The degradation mechanism and characteristics of benzene are still unclear.Clarify the mechanism of benzene degradation by electro-Fenton technology,and put forward a promotion method on this basis,which can significantly improve the treatment effect and greatly reduce the operating cost,laying a theoretical foundation for the development of a clean and efficient benzene treatment technology.The volatilization of benzene under different conditions was studied,and a new type of floating cathode electro-Fenton technology was adopted,which effectively suppressed the volatilization of benzene during electro-Fenton treatment.The degradation characteristics of benzene-containing wastewater were revealed,the reaction mechanism was revealed,and the optimal experimental conditions were clarified;the removal of COD by the anode and various active substances of the floating cathode electro-Fenton system on the benzene-containing wastewater was judged,and the effect of the anode and various active substances in the system was identified.The most critical active substances in the system were identified;activated carbon was used as a modified cathode material,and through reasonable modification,the adsorption and electrochemical performance of the cathode were simultaneously improved,and the treatment effect of the system was improved.Finally,the stability of the activated carbon cathode was studied,and the cost of the novel floating cathode electro-Fenton technology for treating benzene-containing wastewater was calculated.The volatilization of benzene under different conditions was studied.The results show that the continuous oxygen bubbling and temperature increase during the treatment process will lead to the inability to obtain accurate results in the degradation of benzene by the traditional electro-Fenton technology,and the volatilization of benzene will cause serious air pollution.In order to solve the problem of volatilization of benzene,a new type of floating cathode electro-Fenton technology was adopted in this study,which realized the removal of benzene without the need for external oxygen bubbling,and solved the effect of volatilization of benzene on the experiment.When the floating cathode electro-Fenton technology is used to treat benzene-containing wastewater,the oxygen of the cathode comes from the oxygen in the outside air and the oxygen separated from the anode,and the different placement of the floating cathode has an important influence on the removal of benzene.When the floating cathode is located at an equal distance up and down the solution,the cathode can make full use of the above two parts of oxygen,so that the removal effect of benzene is the best.The effects of key experimental factors such as current intensity,p H,ferrous iron concentration,and initial concentration of pollutants on the degradation of benzene in the system were analyzed,and the optimal reaction conditions were clarified.Removal of benzene in the system when C_Benzene=1000 mg/L,C_Na2SO4=50 mmol/L,pH=3,T=20 ℃,I=200m A,C_Fe（Ⅱ）=60 mg/L,and the distance between the plates is 4 cm the effect is the best,and the removal ratio reaches 74.80%.The COD removal ratio was used as a judgment index to judge the removal of COD from benzene-containing wastewater by various active substances generated by the floating cathode electro-Fenton anode and the cathode,and the source of the electro-Fenton system’s ability to degrade benzene-containing wastewater was clarified.The results show that the contribution rate of the active substances produced by the cathode to the removal of COD from benzene-containing wastewater is 63.21%,and the contribution rate of ·OH produced by the cathode to the removal of COD is 58.86%,which is the most important active substance;the contribution rate of HO2· is 4.35%,H₂O₂ and O2-· have no direct COD removal ability.The anode contribution rate is 36.79%.In order to further improve the treatment effect of benzene-containing wastewater and reduce operating costs,low-cost activated carbon was used as the cathode material,and a series of modifications were carried out on the activated carbon cathode,and the modification methods were screened.The material and electrochemical characterization of activated carbon was carried out by relevant analytical methods.The research shows that the treatment effect of H₂O₂ and 900 ℃ high temperature modified activated carbon as a floating cathode is significantly improved,which shows that reasonable modification can improve the oxygen reduction performance of the cathode material surface,improve the operating efficiency of the floating cathode electro-Fenton system,and modified cathode has very good stability.The total cost of the new floating cathode electro-Fenton method for treating benzene-containing wastewater is 6.684 yuan / m3,which is significantly lower than the traditional electro-Fenton wastewater treatment method.This is the treatment of benzene-containing wastewater.And this method is expected to be further promoted and developed.