Preparation And Application Of Composite Micro Nano Fiber Membrane With Silver Loaded Titanium Dioxide

With the rapid advancement of industrialization and urbanization in China,the problem of air pollution caused by PM_2.5 particles in the atmospheric environment has become a focus of attention.Fine particles such as PM_2.5 have small particle sizes,strong activity,and are prone to carrying toxic substances,which can lead to various heart and lung diseases.Traditional air filtration materials have a single function,which limits their application.The preparation of functional filtration materials has become a current research hotspot.Micro nano fibers are widely used in adsorption and filtration fields due to their advantages such as large specific surface area and small pore size.The two most commonly used preparation methods for micro and nano fibers are centrifugal spinning and electrospinning.Among them,centrifugal spinning has high production efficiency,a wide range of raw materials used,and controllable fiber aggregation bulkiness.The fibers prepared by electrospinning have the advantages of small diameter and high porosity.This project combines the advantages of two spinning methods to prepare air filtration materials by combining fibers prepared by centrifugal spinning and electrospinning.The main research content and results are as follows:（1）Polystyrene/cellulose acetate（PS/CA）fibers were prepared using centrifugal spinning method,and the influence of spinning parameters on the fiber morphology and structure during the centrifugal spinning process was investigated.Research has found that the diameter of fibers increases with the increase of spinning solution concentration,and decreases with the increase of centrifuge speed and collection distance.The optimal spinning parameters were optimized to determine a PS/CA spinning solution concentration of 24 wt%,a ratio of 8:2,a centrifuge speed of 10000 r/min,and a collection distance of 12 cm.Under these conditions,the prepared fibers exhibited uniform morphology.（2）Silver loaded titanium dioxide（Ag/TiO₂）nanoparticle composites were prepared by depositing nano Ag on the surface of TiO₂ by UV reduction,and Ag/TiO₂ nanoparticle was blended with PS and CA by centrifugal spinning to prepare Ag/TiO₂/PS/CA composite fibers.It was found that the prepared Ag/TiO₂ nanoparticles were evenly distributed.When the amount of nanoparticles was 2 wt%,the morphology of the Ag/TiO₂/PS/CA composite fiber was uniform,and the nanoparticles could be evenly distributed on the fiber surface.After loading nano silver,the antibacterial properties of Ag/TiO₂ composite materials and Ag/TiO₂/PS/CA composite fibers were improved.（3）The effects of thickness and nanoparticle addition on the air filtration performance of centrifugal spinning fiber membrane were studied.CA porous fiber membrane was prepared by electrospinning method.Functional bilayer micro nano fiber membrane was prepared by the hot-pressing method using fibers prepared by centrifugal spinning and electrospinning.It was found that the filtration performance of PS/CA fiber was the best when the fiber thickness was 3 mm,and the filtration performance of Ag/TiO₂/PS/CA composite fiber was the best when the addition of Ag/TiO₂ nanoparticles was 2 wt%.The filtration efficiency of the prepared double-layer micro nano fiber membrane can reach 99.26%,and the antibacterial rates against Escherichia coli and Staphylococcus aureus are 98.9% and 99.13% respectively.