Preparation And Properties Of Electrospun Antibacterial Nanofibers

Bismuth tungstate（BWO）has become a research hotspot in wastewater treatment due to its visible light photocatalytic degradation of organic compounds and antibacterial properties.However,its recyclability,solar light utilization and photocatalytic activity still need to be improved.In this paper,bismuth tungstate（BWO）and silver doped bismuth tungstate（Ag-BWO）nanoparticles were prepared by a two-step hydrothermal and calcination method.The effects of different hydrothermal conditions on the morphology,phase,specific surface area,band gap and photocatalytic performance of the nanoparticles were studied,and the nanoparticles that can be loaded on the nanofiber membrane were selected;Ag-BWO/PAN nanofiber membrane was prepared by electrospinning method.Based on electrospinning technology and calcination treatment,pure Ag-BWO nanofiber membrane was prepared by raw material blending method and nanoparticle blending method Degradation and antibacterial properties.The results show that:First,different morphologies of BWO particles were prepared by hydrothermal method at different p H values.The optimal hydrothermal p H value of hydrothermal method in making nano BWO particles was 3;The crystallinity of BWO increased significantly within 4 hours,with the increase of hydrothermal time.After 4 hours,BWO particles showed sheet structure.The crystallinity of BWO can be improved and the ideal BWO nanoparticles can be obtained by calcining at 450℃after hydrothermal treatment for 2 hours.Compared with different surfactants,BWO nanoparticles with high dispersion can be obtained by adding 0.06 mol/L sodium oleate.In the hydrothermal preparation of Ag-BWO nanoparticles,trace Ag doping does not change the bonding mode of Bi and WO₆in BWO crystal,but the increase of crystal plane spacing,the red shift of absorption wavelength,the decrease of band gap and the decrease of photoluminescence emission intensity can effectively inhibit the compound quenching of photogenerated electron hole pairs before the degradation of organic pollutants,and improve the degradation performance under visible light.Under the condition of 10%PAN+2%Ag-BWO spinning solution,the Ag-BWO/PAN nanofiber membrane with uniform particle distribution,good degradation effect and antibacterial effect can be obtained by using 24k V spinning voltage and 1.2m L/h advancing speed.Appropriate amount of silver doping in BWO can improve the photocatalytic degradation and antibacterial properties of Ag-BWO/PAN nanofiber films.Pure Ag doped BWO fiber membrane was prepared by blending raw materials.When the PVP content in the solution is 13%,the fiber film has good degradation and antibacterial properties.With the increase of voltage,the fiber diameter decreases and the surface becomes smooth.The spinning voltage and calcination process of raw material blending method were optimized.Pure Ag doped BWO fiber membrane with good degradation performance and antibacterial effect and high recycle rate could be prepared by using 21k V spinning voltage combined with 200℃1h+500℃1h high temperature gradient calcination.In addition,pure Ag doped BWO fiber membrane was prepared by nano particle blending method.It was found that the mass ratio of Ag-BWO to PVP in the spinning solution had a significant effect on the morphology,degradation and antibacterial properties of the fiber membrane.