A mass flow matching model(MFMM)was established for studying the stable status of solution electrospinning.The study of the solution droplet status at the needle tip focused on various combinations of applied voltages...A mass flow matching model(MFMM)was established for studying the stable status of solution electrospinning.The study of the solution droplet status at the needle tip focused on various combinations of applied voltages and injection rates to figure out their influence on steadily fabricating polyvinyl alcohol(PVA)nanofibers prepared from PVA spinning solutions with two different mass fractions(10%and 16%).The results revealed that during the stable electrospinning,the influence resulted from the change of the injection rate approximately canceled out the impact brought by adjusting the applied voltage,leading to almost the same morphology as that of the PVA nanofibers.And the mass fraction of PVA in the spinning solution dominated the structure and the diameter distribution of the electrospun nanofibers.Under stable electrospinning conditions,the composite membrane was produced by depositing PVA nanofibers on the polyethylene terephthalate(PET)nonwoven substrate for an air filtration test.Furthermore,the prepared composite membrane exhibited a high air filtration efficiency(99.97%)and a low pressure drop(120 Pa)for 300-500 nm neutralized polystyrene latex(PSL)aerosol particles,demonstrating its potential as an alternative for a variety of commercial applications in air filtration.展开更多
Nanofibrous media with both high particle interception efficiency and robust air permeability has broad technological applications in areas including individual protection, industrial security, and environmental gover...Nanofibrous media with both high particle interception efficiency and robust air permeability has broad technological applications in areas including individual protection, industrial security, and environmental governance. However, producing such filtration media has proven to be extremely challenging. Here we reported an approach to preparing and fabricating a polyvinylidene fluoride (PVDF) nanofiber composite filter medium composed of 2D PVDF nanofiber nets and a stable substrate via onestep electrospinning for effective air filtration. PVDF nanofibers are obtained by adjusting the electrospinning process. With the combined properties of ultrasmall diameter, high porosity, and a bonded scaffold, the resulting PVDF nanofiber composite filter medium exhibits a robust high filtration efficiency of 99.901%(equivalent to an F9 rating) for 0.4 mm particles and a long service life (a large dust holding capacity of 36 g/m^2) for ultrafine airborne particles based on the sieving principle and surface filtration behavior. The successful synthesis of PVDF nanofibers medium would not only make it a promising candidate for air filtration, but also provide new insights into the design and development of composite nanofiber structures for various applications.展开更多
In this study, the size distribution of atmospheric aerosol in Beijing was monitored by the scanning mobility particle sizer spectrometer and the optical particle sizer. The size of particles in atmospheric aerosol wa...In this study, the size distribution of atmospheric aerosol in Beijing was monitored by the scanning mobility particle sizer spectrometer and the optical particle sizer. The size of particles in atmospheric aerosol was primarily distributed in the range of less than 1 pm. It showed different changes with the mass concentrations of particulate matters with an aerodynamic diameter of 〈2.5 pm （PM2.5） for different sizes of fine particles. The amount of ultrafine particles （less than about 60 nm） decreased while the larger ones （〉60 nm） increased along with the mass concentration of PM2.5 in atmospheric aerosol. This was be- cause of the formation of the secondary atmospheric aerosol. The polylactic acid （PLA） nanofibers were prepared for filtering the aerosol by electrospinning. PLA nanofiber mats were used as the middle layer to design the composite filter membranes. Atmospheric aerosol was used as dust source in the filtration test. The results showed that the filtration efficiency of the com- posite filter media increased along with the thickness of nanofiber mats, which was controlled by the collection time during electrospinning. Filtration efficiency can be improved obviously by compositing with a thin layer of nanofibers.展开更多
Recently, air pollution has become more serious and started to have a dramatic effect on the health of humans in many large cities. Generally, outdoor personal protection,such as commercial masks, cannot effectively p...Recently, air pollution has become more serious and started to have a dramatic effect on the health of humans in many large cities. Generally, outdoor personal protection,such as commercial masks, cannot effectively prevent the inhalation of many pollutants. Particulate matter(PM) pollutants are a particularly serious threat to human health. Here we introduce a new efficient air filtration mat that can be used for outdoor protection. The new efficient air filter’s nanocomposite materials were successfully fabricated from poly(ε-caprolactone)/polyethylene oxide(PCL/PEO) using an electrospinning technique and solvent vapor annealing(SVA).SVA treatment endows the wrinkled fiber surface and enhances the PM2.5 capture capacity of protective masks. This nanowrinkled air filtration mat can effectively filter PM2.5 with a removal efficiency of 80.01% under seriously polluted conditions(PM2.5 particle concentration above 225 mg m-3).Our field test in Qinhuangdao indicated that the air filtration mat had a high PM2.5 removal efficiency under thick haze.Compared to commercial masks, the fabricated SVA-treated PCL/PEO air filter mat demonstrated a simpler and ecofriendly preparation process with excellent degradation characteristics, showing wide potential applications with a high filtration efficiency.展开更多
Oil particle removal,different from the removal of general salt particular matter,has an unusual filtration process in which oil particles will be captured by forming a continuous film on the surface of the filter.The...Oil particle removal,different from the removal of general salt particular matter,has an unusual filtration process in which oil particles will be captured by forming a continuous film on the surface of the filter.Therefore,it is important to investigate the effect of surface property of the filter on the oil particle dynamic filtration process.In this study,three fibrous mats with different surface energies were fabricated from polyacrylonitrile(PAN),polyacrylonitrile/cellulose acetate(PAN/CA),and polyacrylonitrile/polyvinylidene fluoride(PAN/PVDF)solutions by needleless electrospinning.PAN/PVDF fibrous mat presented the lowest surface energy(19.99 mJ/m2),followed by PAN/CA fibrous mat(29.49 mJ/m2)and PAN fibrous mat(40.91 mJ/m2).As the oil particle filtration went on,the PAN/PVDF fibrous mat presented both the fastest filtration efficiency decline(4.72%in 10 min)and the fastest filtration resistance increase(543.41 Pa in 10 min).展开更多
文摘A mass flow matching model(MFMM)was established for studying the stable status of solution electrospinning.The study of the solution droplet status at the needle tip focused on various combinations of applied voltages and injection rates to figure out their influence on steadily fabricating polyvinyl alcohol(PVA)nanofibers prepared from PVA spinning solutions with two different mass fractions(10%and 16%).The results revealed that during the stable electrospinning,the influence resulted from the change of the injection rate approximately canceled out the impact brought by adjusting the applied voltage,leading to almost the same morphology as that of the PVA nanofibers.And the mass fraction of PVA in the spinning solution dominated the structure and the diameter distribution of the electrospun nanofibers.Under stable electrospinning conditions,the composite membrane was produced by depositing PVA nanofibers on the polyethylene terephthalate(PET)nonwoven substrate for an air filtration test.Furthermore,the prepared composite membrane exhibited a high air filtration efficiency(99.97%)and a low pressure drop(120 Pa)for 300-500 nm neutralized polystyrene latex(PSL)aerosol particles,demonstrating its potential as an alternative for a variety of commercial applications in air filtration.
基金supported by the Science and Technology Project of Chaoyang District, Beijing, China (CYGX1709)the National Key R & D Program of China (2017YFE0101500)
文摘Nanofibrous media with both high particle interception efficiency and robust air permeability has broad technological applications in areas including individual protection, industrial security, and environmental governance. However, producing such filtration media has proven to be extremely challenging. Here we reported an approach to preparing and fabricating a polyvinylidene fluoride (PVDF) nanofiber composite filter medium composed of 2D PVDF nanofiber nets and a stable substrate via onestep electrospinning for effective air filtration. PVDF nanofibers are obtained by adjusting the electrospinning process. With the combined properties of ultrasmall diameter, high porosity, and a bonded scaffold, the resulting PVDF nanofiber composite filter medium exhibits a robust high filtration efficiency of 99.901%(equivalent to an F9 rating) for 0.4 mm particles and a long service life (a large dust holding capacity of 36 g/m^2) for ultrafine airborne particles based on the sieving principle and surface filtration behavior. The successful synthesis of PVDF nanofibers medium would not only make it a promising candidate for air filtration, but also provide new insights into the design and development of composite nanofiber structures for various applications.
文摘In this study, the size distribution of atmospheric aerosol in Beijing was monitored by the scanning mobility particle sizer spectrometer and the optical particle sizer. The size of particles in atmospheric aerosol was primarily distributed in the range of less than 1 pm. It showed different changes with the mass concentrations of particulate matters with an aerodynamic diameter of 〈2.5 pm （PM2.5） for different sizes of fine particles. The amount of ultrafine particles （less than about 60 nm） decreased while the larger ones （〉60 nm） increased along with the mass concentration of PM2.5 in atmospheric aerosol. This was be- cause of the formation of the secondary atmospheric aerosol. The polylactic acid （PLA） nanofibers were prepared for filtering the aerosol by electrospinning. PLA nanofiber mats were used as the middle layer to design the composite filter membranes. Atmospheric aerosol was used as dust source in the filtration test. The results showed that the filtration efficiency of the com- posite filter media increased along with the thickness of nanofiber mats, which was controlled by the collection time during electrospinning. Filtration efficiency can be improved obviously by compositing with a thin layer of nanofibers.
基金supported by the National Natural Science Foundation of China (21473153 and 51771162)Support Program for the Top Young Talents of Hebei Province+2 种基金China Postdoctoral Science Foundation (2015M580214)Research Program of the College Science & Technology of Hebei Province (ZD2018091)the Scientific and Technological Research and Development Program of Qinhuangdao City (201701B004)
文摘Recently, air pollution has become more serious and started to have a dramatic effect on the health of humans in many large cities. Generally, outdoor personal protection,such as commercial masks, cannot effectively prevent the inhalation of many pollutants. Particulate matter(PM) pollutants are a particularly serious threat to human health. Here we introduce a new efficient air filtration mat that can be used for outdoor protection. The new efficient air filter’s nanocomposite materials were successfully fabricated from poly(ε-caprolactone)/polyethylene oxide(PCL/PEO) using an electrospinning technique and solvent vapor annealing(SVA).SVA treatment endows the wrinkled fiber surface and enhances the PM2.5 capture capacity of protective masks. This nanowrinkled air filtration mat can effectively filter PM2.5 with a removal efficiency of 80.01% under seriously polluted conditions(PM2.5 particle concentration above 225 mg m-3).Our field test in Qinhuangdao indicated that the air filtration mat had a high PM2.5 removal efficiency under thick haze.Compared to commercial masks, the fabricated SVA-treated PCL/PEO air filter mat demonstrated a simpler and ecofriendly preparation process with excellent degradation characteristics, showing wide potential applications with a high filtration efficiency.
基金National Natural Science Foundation of China(No.51373033)Yangtze River Scholars(Young Scholars)Program,China(No.51773037)。
文摘Oil particle removal,different from the removal of general salt particular matter,has an unusual filtration process in which oil particles will be captured by forming a continuous film on the surface of the filter.Therefore,it is important to investigate the effect of surface property of the filter on the oil particle dynamic filtration process.In this study,three fibrous mats with different surface energies were fabricated from polyacrylonitrile(PAN),polyacrylonitrile/cellulose acetate(PAN/CA),and polyacrylonitrile/polyvinylidene fluoride(PAN/PVDF)solutions by needleless electrospinning.PAN/PVDF fibrous mat presented the lowest surface energy(19.99 mJ/m2),followed by PAN/CA fibrous mat(29.49 mJ/m2)and PAN fibrous mat(40.91 mJ/m2).As the oil particle filtration went on,the PAN/PVDF fibrous mat presented both the fastest filtration efficiency decline(4.72%in 10 min)and the fastest filtration resistance increase(543.41 Pa in 10 min).
