Preparation And Properties Of Semi-Conductor Photocatalyst Loaded Composite Nanofiber Membrane

With the rapid development of textile industry and the wide application of dyes in the dyeing and finishing process,the water pollution caused by the discharge of textile dyes has seriously affected the earth’s water resources and human health,so it is urgent to deal with the pollution of colored dyes scientifically.Photocatalysis is an efficient and environmentally friendly way to degrade dyes.Semiconductor photocatalysis is widely used in photocatalytic degradation of dye wastewater because of its high catalytic activity,non toxicity and environmental protection.In this paper,electrospinning,hydrothermal synthesis and surface impregnation are used to combine the photocatalytic properties of semiconductors with the nano effect of nanofiber membranes.In other words.polyacrylonitrile(PAN)nanofiber membranes are used as substrates to support the semiconductor materials MoS2 and TiO2.The composite nanofiber membranes with photocatalytic properties are prepared and applied to organic dyeing degradation of rhodamine B.The specific work completed is as follows:Firstly,porous PAN nanofiber membranes were prepared.PAN/PEG composite nanofiber membranes were prepared by electrospinning,and the effects of different PEG molecular weight and concentration on the morphology of the fibers were investigated.When the molecular weight of PEG is 4000,the pore size of PAN/PEG fiber membrane is the best.Then,with the porous PAN fiber membrane with the best pore size as the carrier,MoS2 loaded composite nanofiber membrane was prepared by surface impregnation.MoS2 was synthesized by hydrothermal method.The effects of hydrothermal time and temperature on the morphology and structure of MoS2 were studied.The results showed that MoS2 synthesized at 220℃ and 24 hours hydrothermal condition had the most uniform morphology and the best thermal stability.When it was loaded on porous PAN nanofiber membrane and applied to photocatalytic degradation of rhodamine B solution,the degradation time is 5 hours,and the final degradation rate reached 93.1%.Then,the above-mentioned two-step method to prepare composite fiber membrane was improved.MoS2 powder was directly added to different concentration of PAN solution,and PAN/MoS2 composite nanofiber membrane was prepared by electrospinning,and characterized by SEM,TEM,FTIR and XRD.Finally,MoS2 was successfully loaded on PAN fiber.The photocatalytic degradation of rhodamine B solution was carried out by PAN/MoS2 fiber membrane with different concentrations.It was found that 9%PAN/MoS2 fiber membrane had the best photocatalytic effect and the degradation rate reached 89.8%.Finally,TiO2 was grown on the surface of PAN/MoS2 fiber by hydrothermal synthesis,and the composite nanofiber film loaded with MoS2 and TiO2 was prepared.The results showed that the composite fiber membrane prepared in the hydrothermal system of 120℃,8h,1M HCl had the best morphology,the most TiO2 loading,and the best photocatalytic effect.The degradation rate was 93.2%.Rhodamine B was degraded three times,and the degradation rate remained above 90%.