Controllable Preparation Of Polyamide-56 Nanofibrous/nets Membranes For Air Filtration

With the continuous development of modern industry, air pollution problems have become increasingly prominent. Especially PM2.5 air pollution, which has attracted the attention of national, in the recent, frequent haze pollution problem nationwide showed broad sources of pollution, affecting a wide range of long duration and other characteristics, threat to human health. Seriously affecting the normal life and the lives of people. In industrial production, the air of dust and other particulate matter will not only cause wear and tear of industrial equipment, reduce productivity and shorten the life, and even lead to the failure of high-precision instruments and is not working; the same time, ultrafine particles carried by viruses and bacteria also would jeopardize food, medicine and other product quality, seriously restricting the rapid and efficient development of economy and society. Therefore, the development of ultra-fine air filtration materials is related to environmental quality, a major issue livelihood health.In this thesis, polyamide-56(PA56) is chosen as the polymer to prepare nanofibrous/nets membranes through electrospinning, on the consideration of its desirable properties, such as good mechanical property and environmental friendly. We investigated the influence of the concentration of PA56 solution, the ratio of formic acid and acetic acid and the process parameters on the structure and performance of fibrous membrane. The results show that PA56 nanofibrous membranes could achieve the optimized filtration performance when the concentration of PA56 solution is 18 wt% and the ratio of formic acid and acetic acid is 3. Owing to the high coverage of nanonets and the cavity structure between fibers, PA56 nanofibrous/nets membrane has the extremely excellent filtration performance, for 300-500 nm NaCl airborne particles, its filtration efficiency can reach 99.995%, at the same time, the pressure resistance just is 111 Pa.To systematically elaborate the excellent performances and encourage perspectives of the PA56 nanofibrous/nets membranes, the comparison of filtration efficiency, pressure drop, and quality factor under various face velocities among Hollingsworth & Vose(H&V) typical HEPA(HB7613) and sub-HEPA(HC4683) glass media, PA56 nanofibers, and PA56 nanofibrous/nets medium. The results showed that the filtration efficiency of PA56 nanofibrous/nets membranes can be more than 99.99% and the resistance pressure drop significantly lower than the other three kinds of filter membrane materials, which confirming the contribution of 2D nanonets on improving the filtration efficiency based on physical sieving manner, especially under a high face velocity.Finally, this paper focuses on the dust holding capacity and the regeneration ability, which are very important performance parameter for the airborne particle filtration. By comparing H&V HB7613 with PA56 nanofibrous/nets membranes, showed that the dust holding capacity of the PA56 nanofibrous/nets membranes and H&V HB7613 filters at end-of-life state were 49 and 28 g/m2, respectively, revealing a longer service life benefited from the surface filtration and physical sieving manners of PA56 nanofibrous/nets membranes. At the same time, by mechanical shaking and/or air back blowing treatments, the PA56 nanofibrous/nets membranes can be used several times.