| A large amount of organic wastewater is discharged in the daily production and production process,resulting in the proliferation of microorganisms.Environmentally friendly sewage treatment technology treats wastewater.Electrocatalytic membrane technology combines membrane separation and electrocatalytic oxidation technology effectively.It has the advantages of more energy-saving,no secondary pollution and continuous treatment.It not only improves the removal efficiency of microorganisms,but also saves energy and protects the environment.A new type of technology and method has received wide attention.In this paper,a simple electroreduction-hydrothermal oxidation method is adopted,in which a carbon membrane is used as a base membrane.Under the action of an electric field,Sn2+ and Bi3+ are first adsorbed and reduced to metal Sn and Bi at the surface of the membrane,and then Bi-doped SnO2 electrocatalytic membrane(Bi-SnO2/CM)was prepared by hydrothermal oxidation.The composition and electrical properties of the electrocatalytic membrane were analyzed by SEM,XRD,LSV,CV and EIS.The results show that Bi-SnO2 is tightly bound to the carbon membrane through C-O chemical bond,which enhances the active site of the electrocatalytic membrane and makes the electrocatalytic membrane exhibit excellent removal performance against E.coli.When the Bi:Sn molar ratio is 0.15,the electroreduction time is 60 min,and the current is 0.2 mA,the obtained electrocatalytic membrane has the best performance.The oxygen evolution potential reaches 1.74 V and the electrochemical corrosion time can reach 44.5 h.Then,the removal performance and process conditions of electrocatalytic membrane for E.coli were studied.The single factor experiment was carried out by changing the time,flow rate,voltage and the like of the electrocatalytic membrane to treat the aqueous solution of E.coli.At the same time,the main oxidizing groups of electrocatalytic oxidation were investigated by the addition of a scavenger.The experimental results show that due to the synergistic effect of membrane separation and electrocatalysis,the sterilization efficiency can reach more than 99.99%under the conditions of power supply voltage of 4 V,flow rate of 1.4 mL/min and initial concentration of E.coli 1.0×104 CFU/mL,Further,it has been found that the oxidizing group of the OH radical generated by Bi-SnO2/CM plays a vital role in the bactericidal performance.Finally,the natural river water was treated with an electrocatalytic membrane to investigate the effect of electrocatalytic membrane on the removal of microorganisms in natural river water.The removal rate of the total number of colonies by electrocatalytic membrane was 95.6%,indicating that the electrocatalytic membrane still had a good sterilization effect on microorganisms in river water.In summary,the subject uses carbon membrane as the base membrane,and Bi-SnO2/CM is prepared by electroreduction-hydrothermal oxidation method,and is used to treat microorganisms in water,to obtain the process conditions for removing microorganisms,and to explore the mechanism of inactivation.It is indeed possible to increase the oxygen evolution potential to increase the inactivation efficiency of the electrocatalytic membrane.The study provides a low-cost,highly active and stable electrocatalytic membrane that can be used for continuous microbial inactivation and has great potential for water treatment,facilitating the large-scale application of microbes in water treatment by electrocatalytic membranes. |
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