Sandwich structured polyamide-6/polyacrylonitrile nanonets/bead-on-string composite membrane for effective air filtration

Tailoring Mechanically Robust Poly(m-phenylene isophthalamide) Nanofiber/nets for Ultrathin High-Efficiency Air Filter

“…1e. Obviously, the increased fiber diameter allowed the pore size stacked by the fibers to increase sharply, favoring both the particles penetration and airflow through the membranes18. Moreover, the randomly distributed nanowires in membranes from 10 and 12 wt% PMIA solutions could slightly enhance the effective contact area for capturing NaCl particles, and thus endowed the membranes with higher removal efficiency.…”

“…Somewhat surprisingly, the optimized PMIA NF/N filter with a superlight weight of 0.365 g m −2 and ultrathin thickness of ~0.5 μm, exhibited an extremely high filtration efficiency of 99.999% (ULPA filter standard) for the ultrafine airborne particles while maintaining a low pressure drop of 92 Pa, indicating the key role of the novel nanonets in improving the application performance of the air filters. To further evaluate the time dependent behaviour (service life), we employed the testing method mentioned in our previous studies (as described in the Supplementary Method)18, to systematically investigate the dust holding capacity of the PMIA NF/N filters. Figure S5 exhibits that during the continuous silica particles feed, the dust holding capacities and pressure drops of the filter increase simultaneously, and achieve a rather high dust holding capacity of ~45 g m −2 , thus confirming its longer service life benefited from the surface filtration and physical sieving manner.…”

“…The properties of PMIA precursor solutions were systematically tested by the methods mentioned in our previous study1718; however, the charge to mass ratio ( e/m ) of the charged fluid (jets and/or droplets) during ESN was measured by the typical “mesh target” method using a digital multi-meter (Fluke F15B+, Fluke electronic instrument Co., Ltd., China)30. Morphology of relevant samples was examined by using an S-4800 field emission scanning electron microscopy (FE-SEM) (Hitachi Ltd., Japan).…”

“…Compared to various methods including drawing, flash-spinning, sea-island spinning and template synthesis, electrospinning has been widely regarded as a robust and scalable nanotechnology for producing nanofibers with organic/inorganic components and designed structures12131415. Many electrospun fibers (diameter 100–1000 nm), including polyurethane (PU)16, polyacrylonitrile (PAN)1718, polyvinyl chloride/PU5, polyamide-5619, poly(lactic acid)20, and nylon-6621, have been carefully fabricated and gained significantly improved filtration performance22. Nevertheless, some drawbacks still remain, such as limited structural controllability, weak mechanical properties, low production rates, and a low quality factor indicating an inadequate filtration performance.…”

Needleless electrospinning for scaled-up production of ultrafine chitosan hybrid nanofibers used for air filtration

“…Because of their unique properties of the electrospun nanobers such as high surface area, high aspect ratio, good mechanical properties and the ability to incorporate multifunctional nanoparticles in the bers, the resulting product can be an excellent lter medium for air and water contaminants purication. [8][9][10][11][12][13][14][15] The main difficulties focus on the high throughput, functionalization and ber diameter reduction, while maintaining nanobers stability. Chitosan is recognized as the second most globally abundant natural polysaccharide aer cellulose.…”