Electrospinning Prepares A Nanofiber Air Filter Membrane That Efficiently Removes Fine Particles

Electrospinning technology,as one of the effective methods for preparing nanofibers,has the advantages of simple device,multiple spinnable types,low cost and controllable process.Therefore,electrostatic spinning technology can be applied in the fields of clothing,food,energy,filtration,medical,electronics and so on.First,we have proved the feasibility of preparing polytetrafluoroethylene/polyvinyl alcohol（PTFE/PVA）nanofibers by electrospinning technology under the condition of PTFE microfiber membrane.Then,PVA in the fiber membrane was removed by heat treatment at about 350℃.Compared with the PTFE microfiber substrate,the filtration efficiency of the composite PTFE fiber membrane is increased by 70%,and the water contact angle is increased by 23°.Experimental test data showed that the water contact angle of the sample increased from 107°to 130°,the filtration efficiency for PM2.5 increased from 44.778%to 98.905%,and the filtration efficiency for PM7.25 increased from 66.655%to 100%.The reason is that the PTFE nanofiber layer prepared by electrospinning can effectively capture particulate matter,improve the hydrophobicity of the fiber membrane,and the air permeability is only slightly reduced.This work demonstrates the potential of PTFE composite fiber membranes as air filters for indoor or outdoor dust removal and industrial-related gas filtration.Then a method for preparing nano-fiber anti-smoke screens by electrospinning on a large scale is introduced.Particulate matter（PM）has severely affected human life,such as affecting human health,climate and ecological environment.Recently,many researchers have used electrospinning to make nanofiber air filters to effectively remove particulate matter.However,polymer fibers can be evenly electrospun onto screens only in the laboratory,and industrialization is still very challenging.Here,we report a method of electrospinning using wire electrodes to electrospun thermoplastic polyurethane（TPU）on a conductive mesh on a large scale to prepare a nanofiber air filter.By changing the concentration of TPU in the polymer solution,the PM2.5removal efficiency of the nanofiber air filter can reach 99.654%,good optical transparency is 60%,and the contact angle and ventilation rate of the nanofiber air filter are 128.5°and 3480 mm s^-1,respectively.After 10 times of filtration,the removal efficiency was only reduced by 1.6%.This TPU nanofiber-based transparent air filter has excellent filtration efficiency and ventilation rate,which can effectively ensure the indoor air quality of residential buildings.