2018-06-25

PVA-co-PE Nanofibrous Filter Media withTailored Three-Dimensional Structure for High Performance and Safe AerosolFiltration via Suspension-Drying Procedure

Abstract: High efficient filtration of airpollutants exerts a great demand for nanofiber-based materials with superiorstructures. In this work, a mixed solution of tert-butyl alcohol (TBA) andwater was employed to stably disperse PVA-co-PE nanofibers. Nanofibrous filtermedia based on PP nonwoven fabric substrate with various porosity were thenprepared via three nanofiber-suspension drying techniques: spray-air-drying,spray-freeze-drying, and container loading-freeze-drying. The preparednanofiber composite filter media with average nanofiber diameter about 155 nmpresent controllable three-dimensional structure: nanofiber layer porosityincreases from 76.6% to 97.3%, various pore sizes increase from 0.493 to 2.268μm, as well as an increased nanofiber layer thickness from about 10 to 55.3 μmfor filter media with 2.667 g/m2 nanofiber coverage density (NFCD). On thebasis of the structure, filter media possess a best comprehensive filtrationperformance with the quality factor 1.110 mmH2O–1 (99.955% and 6.73 mmH2O) atNFCD = 2.677 g/m2 and a best efficient performance with efficiency 99.999%(0.645 mmH2O–1 and 17.86 mmH2O) at NFCD = 6.583 g/m2, respectively. Thetheoretical analysis shows the excellent properties are mainly derived from thestable three-dimensional structure of nanofiber network which can providesuperior torturous channels for capturing airborne nanoparticles andfacilitating the penetration of air flow indicating a typical deep bedfiltration. The result of electret treatment test shows that the filter mediumexhibits remarkably stable filtration properties and is basically insusceptibleto the electrostatic charges rather than the commercial PP nonwoven fabricsubstrate. Furthermore, the repetitive-use test showed that present nanofibrouscomposite filters possess higher dust holding capability (24.3 g/m2) and longerservice life (8.5 h) than commercial filter with the similar initial filtrationproperty. This implies the superiority of present nanofiber composite filtermedia in the application as a high stable, cost-effective, and safer air filtermedium.

Yi Zhibing, et al. PVA-co-PE nanofibrousfilter media with tailored three-dimensional structure for high performance andsafe aerosol filtration via suspension-drying procedure. Industrial &Engineering Chemistry Research, 2018, 57, 9269-9280.