Preparation And Performance Study Of Carbon Nanotube/titanium Dioxide-polyethersulfone Nanocomposite Membrane

Ultrafiltration(UF)membrane separation technology is widely used in water treatment and other fields due to its advantages of low operating pressure,high flux and high interception rate of albumin and colloids.In actual use,all membranes have different degrees of membrane fouling problems,which increases the cost of operation and membrane replacement.Therefore,the modification of ultrafiltration membrane to improve the anti-pollution ability of membrane is an important research direction of ultrafiltration membrane technology.In this paper,polyethersulfone(PES)-based organic-inorganic hybrid membranes were prepared by phase inversion using carbon nanotubes and self-made carbon nanotubes/titanium dioxide hybrid materials as modifiers.The structure and performance of hybrid membranes were characterized by fourier transform infrared spectroscopy,scanning electron microscopy,atomic force microscopy,mechanical properties,water contact angle test,membrane flux test,photocatalytic performance test and antibacterial performance test.Firstly,the effects of the addition amount and diameter of carbon nanotubes(fMWNTs)on the membrane structure and properties were investigated.The results showed that the tensile strength and Young's modulus of the blend membrane first increased and then decreased with the increase of fMWNTs content,and decreased with the increase of the diameter of fMWNTs.When the addition amount of fMWNTs was 1.0 wt%and the diameter of the tube was 20-30 nm,the contact angle of the PES/fMWNTs blend membrane was reduced,and the pure water flux reached 50.39 L/m2·h,which is 4 times of the pure PES flux.The retention rate of bovine serum albumin(BSA)was maintained above 95%,the flux recovery rate increased to 84.59%,and the anti-pollution performance was significantly improved compared with pure PES membrane.Secondly,multi-walled carbon nanotubes/titanium dioxide(fMWNTs/TiO2)hybrid materials were synthesized by hydrothermal method and sol-gel method.The photocatalytic properties of methyl orange(MO)as the target degradation product were evaluated.The effects of butyl titanate(TBT)content,hydrothermal pH and temperature on the UV-catalyzed MO by fMWNTs/TiO2 hybrids were studied.The photocatalytic activities of MO and methylene blue(MB)in the photocatalyst prepared by hydrothermal method and sol-gel method were compared.The results showed that the grain size of TiO2 nanoparticles was smaller and uniformly coated on the surface of fMWNTs,and the crystal form was pure anatase.The photocatalytic degradation performance of fMWNTs/TiO2 photocatalyst was better than that of pure TiO2,and the photocatalytic performance of fMWNTs/TiO2 photocatalyst prepared by hydrothermal method on MO and MB under sunlight was better than that of sol-gel method.Finally,fMWNTs/TiO2-PES nanocomposite membrane was prepared by phase inversion method.The study showed that the anti-pollution performance of fMWNTs/TiO2-PES nanocomposite membrane was obviously improved,and it had good photocatalytic activity and self-cleanin g to MO and MB under UV light,and showed good bacteriostatic effect against gram-negative bacteria E.coli.