| As China gradually enters industrialization,the problem of water pollution caused by antibiotics is becoming increasingly serious.If it is discharged into the environment for a long time,it will increase the resistance of sensitive bacteria,which poses a potential threat to the ecological environment and human health.Therefore,the optimization of the technology for the treatment of antibiotic wastewater is urgentThe ultrafiltration membrane filtration technology has the functions of separation,purification,concentration and purification,as well as the advantages of high efficiency,energy saving,environmental protection,simple process and easy control However,due to the increasing water discharge standards,diverse pollutant composition,membrane fouling caused by organic pollutants,macromolecules,and lack of stability have limited its development and applications.In recent years,the development of electrochemical membrane filtration technology has provided an effective solution to the problem of water pollution.It allows the filtration and degradation of pollutants to be carried out at the same time,to achieve efficient sewage harmless treatment,and to solve membrane pollution problems,new advances in research in the field of processing.However,this process is often ignored in the treatment of diverse and complex new organic pollutants,while achieving anti-pollution and membrane regeneration.In addition.the current methods of preparing electrochemical membranes are more complex and are prone to secondary pollution,which limits the application of electrochemical membranes Therefore,designing efficient preparation methods of electrochemical membranes,studying the collaborative treatment of new organic pollutants by electrochemical membrane filtration systems,and improving the anti-fouling performance and system stability of electrochemical membranes are of great significance for the development of electrochemical coupling membrane filtration systems.Carbon fiber cloth(CF)as a cheaper carbon-based substrate,is considered as a good choice for electrode manufacturing.In this thesis,a CF/SiO2/PES conductive ultrafiltration membrane based on carbon fiber cloth was constructed,which combined with electrochemical technology to efficiently treat tetracycline wastewater,while improving the membrane's pollution resistance and system stability.The main research contents and conclusions of this article are as follows(1)Using a phase inversion method,a silica sol gel(SiO2)and a polyethersulfone(PES)were modified on a carbon cloth substrate to prepare a CF/SiO2/PES conductive ultrafiltration membrane.Through SEM and XPS and other characterization methods,it was proved that SiO2 sol-gel and PES were successfully loaded on the carbon cloth substrate.The AFM analysis of the surface of the prepared conductive film shows that it has an extremely smooth surface,which effectively reduces the occurrence of film contamination.Compared with bare carbon cloth(CF),the contact angle of CF/SiO2/PES film is reduced to 70.96°,and the hydrophilicity is increased.However,its water flux,porosity and moisture content are all reduced.To some extent,the pore size of the bare carbon cloth has been changed,which also indicates that the membrane material is more conducive to filtering small molecular substances.The Zeta potential test shows that the negative charge on the surface of the membrane is beneficial to the phenomenon of electrical repulsion or adsorption when the charged molecules are filtered by the membrane,and improves the separation efficiency of the membrane.A preliminary analysis of the performance of the constructed electrochemically-assisted CF/SiO2/PES membrane filtration system was performed using a phenol removal experiment.The highest removal efficiency is 95.81%when 5mg/L phenol,20mM NaCI,pH=2,and an applied voltage of+3V Phenol is mainly degraded into hydroquinone,resorcinol,catechol and hydroquinone by hydroxyl radical(·OH).The system maintained high removal efficiency after 8 cycles of filtration experiments,and the flux recovery rate was 83.27%.In summary,this system has feasibility,excellent phenol removal,and good reproducibility(2)Analyze the removal performance of tetracycline wastewater by electrochemically assisted CF/SiO2/PES membrane filtration system.The decrease in the normalized flux of the CF/SiO2/PES membrane decreases with the increase of the applied voltage,which indicates that tetracycline is degraded into small molecules under the condition of power-on,which is not easy to form a pollution layer on the membrane surface and cause flux.Reduce and effectively alleviate membrane pollution.Compared with bare carbon cloth(CF)and membrane material(CF/SiO2)that only supports SiO2,the flux of CF/SiO2/PES membrane is normalized and the removal efficiency is increased?which are 53.30%and 55.66%higher than the previous two,respectively.In addition,the removal efficiency was the highest at 10 mg/L tetracycline,pH=3,and an applied voltage of+5V,and the removal efficiency was 93.35%.Based on the CV curve and EPR test results,it was found that the degradation of tetracycline was mainly due to the oxidation of hydroxyl radicals(·OH),and a complete tetracycline degradation path was obtained using HRMS Membrane circulation filtration experiments show that the flux recovery rate under power-on conditions is better than when there is no applied voltage,mainly due to the inhibition of membrane fouling due to electrochemical oxidation.Under the conditions of pH=3.0 and pH=9.0,the removal efficiency of tetracycline after multiple cycles was only 0.74%and 1.95%,respectively.This indicates that the auxiliary effect of electrochemistry provides advantageous technical support for the inhibition of membrane foulingIn summary,CF/SiO2/PES membrane has good anti-pollution performance with the aid of electrochemical oxidation technology,and can maintain strong reproducibility when dealing with macromolecular refractory pollutants.An important step has been taken in the process of filtering new organic pollutants. |
PDF Full Text Request