Electrospun PS/PAN Nanofiber Membranes Formed from Doped Carbon Nanotubes with a Fluffy and Multi-scale Construction for Air-Filtration Materials

Electrospun nanofibers are widely used in air-filtration materials because of their fine fiber diameter, small pore size, and high porosity. However, nanofiber membranes exhibit a dense structure, such that they present a large resistance to any air flow. In this study, we set out to design and develop composite nanofiber materials with fluffy structures, as well as blended structures of coarse and fine fibers, through electrospinning technology. These materials could be used in air filtration applications, given that they offer high efficiency and low resistance. The results show that, compared with pure PAN nanofibers, the diameter of PAN nanofibers doped with CNT decreased from 192.36 to 124.37 nm; when the spinning ratio of PS coarse fiber (1053 nm) and PAN/CNT fine fiber is 3:1, the resulting nanofiber membrane materials has an obvious three-dimensional structure, with a specific surface area of 103.16 m 2 /g, a pore size of 2.25 µm, and a quality factor of 0.0947 Pa −1 . Under test conditions featuring an air flow of 32 L/min, and 0.3 µm NaCl aerosol particles, the filtration efficiency was 99.37 % and the resistance was 35 Pa. Furthermore, the dust-holding capacity of the nanofiber air-filter paper was found to be almost the same as that of melt-blown air-filter papers. Even after being water-soaked 50 times, the filtering efficiency of the nanofiber air-filter paper was still higher. Interestingly, the nanofiber membrane materials doped with CNT also exhibited excellent sound-absorption abilities. Thus, the composite nanofiber material could potentially be applied to areas with serious air pollution and high noise pollution.