Electrochemical Assisted Coal-based Carbon Film And Silver Nanowire-carbon Nanotube/coal-based Carbon Film Antibacterial And Anti-fouling Performance Research

Membrane separation technology is widely used in water treatment.However,the membrane materials without antibacterial activity at present.In the process of use,the membrane fouling formation easily,due to bacteria and other microorganisms adhere to the membrane surface,resulting in a dramatic flux loss.The membrane fouling leading to reduced efficiency of membrane filtration and the service life 'of membrane.In this paper,in view of the membrane biofouling,the electrochemical assisted filtration technology was designed,and the antibacterial and antifouling performance of the membrane was investigated.Then,on this basis,the electrochemical assisted filtration combined with the antibacterial modification of the membrane,The antibacterial and antifouling properties of membrane with electrochemical assistance were systematically studied.The main contents are summarized as follows:(1)Research on the properties of membrane:Using an electric auxiliary filtration system,Escherichia coli(E.coli)with concentration of 104 CFU/mL as the filtration target to study the antibacterial and antifouling properties of the membrane.The experimental results indicate that the removal efficiency of E.coli of the membrane reaches 97%without an external voltage application,and the membrane flux is declined in 32%;The removal efficiency of E.coli of the membrane is improved under an external positive voltage application,which can reaches 100%,however,the membrane flux decreased sharply.The voltage of 2 V,2.5 V,3 V was applied on the membrane surface,the membrane flux is decreased by 49%,39%,and 46%,respectively.The membrane pollution is aggravated due to the effect of electrostatic attraction.The removal efficiency of E.coli of the membrane is can reaches 100%under an external negative voltage is higher than 2 V.The membrane flux tends to be steady with the addition of voltage.When the membrane with-3.5 V voltage application,the membrane has a good removal efficiency of bacteria and the filtration performance.The membrane flux decreases to 86%of the initial flux in one hour.The reason of the mitigation of membrane fouling is the electrostatic repulsion generated to prevent the initial adhesion of bacteria to improve the antibacterial of the membrane.In the decline trend of the membrane flux gets slow obviously under an external negative voltage application,and there is still room for improvement.(2)Preparation of AgNW-CNT/C membrane and research on the antibacterial and antifouling properties of membrane:the coal based carbon membrane as the carrier and the antibacterial composite membrane was prepared by loading AgNW-CNT on the membrane surface.The separation and antibacterial properties of the modified membrane in in an external voltage application and the influence of the antibacterial agent loaded on the membrane surface morphology were investigated.The experimental results showed that at a low voltage of-3.5 V,the removal efficiency of E.coli of the AgNW-CNT/C membrane reaches 100%,and the flux of membrane was stable with neglectable flux loss,while the steady-state flux declined to 70.5%for AgNW-CNT/CC membrane without an external voltage.Because of the antibacterial agent of the AgNWs have excellent antibacterial performance,which caused the bacteria inactive and inhibited the biofilm formation.Meanwhile,membrane in in an external voltage application produced electrostatic repulsion can significantly inhibit the bacteria migration to the similarly charged membrane surface and the bacteria adhesion on the membrane surface have reduced.From the scanning electron microscope(SEM)results,it can be seen that the AgNW-CNT layer presented a cross-linked net structure on the membrane surface without visible drawbacks of pin-hole and cracks,thus,the porosity of the membrane surface is increased,and the rejection efficiency of the membrane is improved.The results indicate that the combination of electrical effect and antibacterial modification can significantly improve the filtration performance and antibacterial activity of the membrane,which provides a new insight for the membrane separation technology.In summary,the membrane fouling acquires improvements to a certain extent by both electrochemical assisted filtration and antibacterial modification.In particular,when the above two methods are combined,the antibacterial performance of membrane can significantly improvement by their collaboration,and the membrane fouling to minimize the risk,which provides new ideas to solve the membrane pollution.