Study On Electrochemical Disinfection Of Electrospun Composite Nanofiber Membranes Loaded With Single Wall Carbon Nanotubes

Water pollution caused by pathogenic microorganisms remains a major public health problem in developing countries.At present,due to the limitations of disinfection technology and the complexity of the water supply environment,a large number of people still do not have access to safe and clean drinking water.Therefore,it is of practical significance to develop new materials and technologies for point-of-use(POU)drinking water disinfection.In this paper,we blended SWNTs,polyacrylonitrile(PAN),polyurethane(TPU),and polyaniline(PANI)and prepared single-walled carbon nanotube-polyacrylonitrile / polyurethane / polyaniline(SWNTs-PAN / TPU / PANI,SPTP)composite electrode with high strength,long-lasting sterilization and(ecological)toxicology mitigation effect by electrospinning technology.POU drinking water treatment electrochemical filter sterilization system was constructed.FTIR,FESEM,TEM,BET and EIS were used to characterize the microscopic morphology and physicochemical properties of SPTP composite nanofiber membrane.Through static,filtration and electrochemical disinfection experiments,SPTP composite membrane sterilization influencing factors and efficacy research were carried out.The operation stability of SPTP composite nanofiber membrane was investigated through the circulation experiments,shake flask experiments and membrane flux change tests.SPTP composite nanofibers had a uniform diameter(? 200 nm)without obvious beads,SWNTs were embedded in the surface and fibers of the composite nanofibers in various forms.The addition of SWNTs increased the mechanical strength and electrical conductivity of the composite membrane.The SPTP composite nanofiber membrane had a tensile strength of 3.2 MPa and had good electrical conductivity.The results of static disinfection experiments showed that PAN/TPU(PT)and PAN/TPU/PANI(PTP)composite nanofiber membranes had no sterilization properties.Within 3.0 h,E.coli and S.aureus on SPTP nanofiber membrane were all inactivated.The results of membrane filtration experiments showed that SPTP composite nanofiber membranes were not ideal for inactivation of bacteria retained by filtration,and could only inactivate 0.8 log E.coli and 0.6 log S.aureus.However,the SPTP composite nanofiber membrane could completely remove bacteria in the water through the screening mechanism.The results of the applied voltage filtration experiment showed that the simultaneous application of voltage during the filtration process resulted in the significant inactivation of the retained bacteria.The voltage,duration of pressurization and SWNT load were positively correlated with the disinfection effect,and 5 log E.coli was inactivated within 20 min at 3.0 V.The results of cycle experiments,shake flask experiments,TEM and membrane flux tests showed that SPTP composite nanofiber membrane had good continuous disinfection performance,and the inactivation rate of E.coli still reached 4.8 log after 5 cycles of SPTP device.The loss of membrane flux was only 10.6%.The release amount of SWNTs in the SPTP composite nanofiber membrane was less than 100 ppb.At applied voltage of 1.0 and 2.0 V,the electrochemical deactivation of SPTP composite nanofiber membrane filter was independent of electrolyte concentration and composition.Direct oxidation was the main mechanism of electrochemical sterilization.However,at 3.0 V,the electrolyte concentration and the composition had a direct effect on the electrochemical deactivation,and the sterilization effect was ranked as: 100 m M Na Cl> 10 Mm Na Cl> 10 m M Na2SO4.The reactive oxygen species(ROSs)produced in the SPTP electrochemical sterilization system played a major sterilization role and serve as an indirect oxidative inactivation mechanism.