Development And Application Of Nanofiber Air Purification Materials With Fluffy Structure And Electret Effect

With the rapid development of society,people's quality of life has been qualitatively improved resulting in air pollution becoming more and more serious.How to prevent the pollution of PM has become a topic of widespread concern in today's society.At present,the filtration materials on the market are mainly electrostatic melt-blown electret nonwoven materials,which mainly rely on the electrostatic adsorption effect to achieve the filtration effect.However,in the daily use,the electrostatic effect is significantly attenuated by environmental factors(temperature and humidity),and the filtering efficiency is greatly reduced to about 20%.Nanofibers have the advantages of fine diameter,small pore diameter,high porosity and large specific surface area and are widely used in the field of air filtration(industrial filtration and personal protection).In this paper,a variety of PAN composite nanofiber materials were designed and developed by using electrospinning technology and applied in the field of air filtration.Specific research contents are as follows:In order to obtain a uniform morphology of ultrafine nanofiber membrane applied to air filtration materials.In this paper,the fineness of PAN nanofibers was optimized by adding organic salt tetrabutylammonium dihydrate(TBAC)into the spinning substrate,and the effects of TBAC content on the fiber morphology and filtration performance were studied.The results showed that when the concentration of PAN spinning was 12%,the morphology distribution of nanofibers was uniformly distributed,and the diameter of the nanofibers was285.76±75 nm.With the addition of TBAC,the diameter of nanofibers decreased gradually,when the content of TBAC was 0.3 wt%,the morphology of nanofibers was uniformly distributed,with the diameter of 183.92±47 nm,the pore diameter of nanofiber membrane was 1.64±0.28?m,and the specific surface area increased from 33.71 m²/g to 54.45 m²/g.Under the test conditions of 32 L/min and 0.3?m Na Cl aerosol particles,the best filtration efficiency of nanofiber membrane was(filtration efficiency was 84.27%,filtration resistance was 27 Pa),the quality factor was 0.068 Pa^-1,and the porosity was 89.35%.In order to further improve the filtration efficiency of nanofiber membranes,PAN/CNT ultrafine nanofibers were prepared by doping CNT in PAN matrix in this chapter,and the effects of CNT content on the morphology and filtration performance of the fibers were studied.The results showed that compared with the pure PAN nanofibers,the diameter of the PAN/CNT nanofibers doped with 0.3 wt%CNT decreased from 183.92±47 nm to 116.86±27 nm,the porosity increased to 93.47%,and the specific surface area increased from 54.45m²/g to 86.19 m²/g.In terms of filtration performance,the filtration efficiency of nanofiber membrane increased from 84.27%to 94.42%and the quality factor was 0.0825 pa^-1under 32L/min,0.3?m Na Cl aerosol test conditions.More importantly,the sound absorption performance of the PAN/CNT nanofiber membrane doped with CNT is 1.3 times that of the PAN nanofiber,especially in the middle and low frequency bands.Therefore,the CNT-doped PAN/CNT nanofiber composite membrane prepared in this chapter shows good filtration performance and excellent sound-absorbing performance.PAN/CNT nanofiber composite membrane will have a broad application prospect in hospitals,schools and other special occasions where air quality is high and quiet environment is required.The structure of the filtration material has an important influence on the filtration performance.In this chapter,PAN/PS nanofiber air filter material with fluffy structure and electret effect was designed and developed.In this chapter,the PS/Si₃N₄electret composite membrane with electret effect was prepared by doping electret Si₃N₄particles in the optimized PS matrix,and the structure and properties of the nanofiber membrane were optimized.On this basis,the PS/PAN electronic nanofiber composite membrane was prepared by electrospinning technique,and its structure and properties were characterized systematically.The results showed that when the PS concentration was 22%,the fiber morphology was uniform and the fiber diameter was 1.42±0.58?m.When Si₃N₄is doped into the matrix of PS spinning solution,the diameter of the nanofiber decreased gradually.When the Si₃N₄content was 3.0 wt%,the diameter of the composite nanofiber was more uniform and the fiber diameter was 581.32±151 nm.With the addition of PAN/CNT,the microstructure of nanofibers with alternating thickness appeared in the nanofiber membrane.When the spinning nozzle ratio of PS:PAN was 3:1,the highest specific surface area was117.34 m²/g and the maximum porosity was 96.32%,Under the test condition of 0.3?m Na Cl aerosol particles at 32 L/min,the maximum quality factor of nanofiber membrane is0.09836 pa^-1,the filtration efficiency and filtration resistance are 95.99%and 32.7 Pa,respectively.The filtration efficiency and filtration resistance of the nanofiber membrane are87.74%and 33.5 Pa,respectively.It can be seen that the nanofiber composite membrane material prepared in this chapter has excellent fluffiness structure and electret effect,and has a wide application prospect in the field of air filtration.On the basis of the above research,the PS/PAN nanofiber filter paper for air purifier was prepared by the combination of gel-spinning and hot-pressing technology in this chapter,and its structure and performance were analyzed.The results show that the optimum process parameters are as follows:the amount of glue is 7.5 m²/g,the hot pressing distance is 4.5 mm,and the hot pressing temperature is 100?.Specifically,under the test conditions of 85 L/min,0.3?m aerosol particles,compared with the unsprayed wood pulp paper,the filtration efficiency and filtration resistance of the filter paper after spraying glue have no obvious change(the filtration efficiency range is 7–9%,the filtration resistance range is 45-47 Pa),The filter efficiency of filter paper increased from 82.4%to 83.2%,and the filter resistance increased from 137 Pa to 152 Pa.Therefore,the PS/PAN nanofiber composite membrane with electret effect prepared in this chapter has important application value in household air purification filter material,and the filter paper of nanofiber air filter has a good application scenario in household,industrial,agricultural and animal husbandry purification fields.