High filtration efficiency fluffy material: nano-fiber constructing gradient structure on recycled curved PET micro-fibers web

Abstract

High efficiency filtration materials focus on electreted melt-blown polypropylene nonwoven and nano-scale fibers membrane in industry. However, the charge decay and the balance of efficiency and resistance are still facing challenges on research and practical applications. In this research, combined with traditional electrospinning and carding process, a simple and new fluffy gradient filtration material was designed by constructing nano-scale poly(lactic acid) (nano-PLA) fiber membranes on recycled three-dimensional curved poly(ethylene terephthalate) (R-PET) micro-fibers webs. Influences of basis weights of nano-PLA membranes and curved types of R-PET fibers on the filtration performance and the dust-holding capacity of R-PET/nano-PLA mats were investigated. Besides, the filtration mechanism of R-PET/nano-PLA mats was systemically studied. Results show that R-PET with zigzag curve (R/Z-PET) possesses the highest filtration efficiency of 99.992% comparing with 99.517% of linear R-PET, the pressure drop fall to 201.11 Pa, and a quality factor level up from 0.024 to 0.047 Pa−1. The pressure raising rate of the R/Z-PET/nano-PLA mat is the slowest. R/Z-PET fibers with a folding angle of 90° benefit to decrease the friction between fiber and particles when the location angle of zigzag fiber is 45° along the airflow direction, which decrease the pressure drop at high filtration efficiency. Surface residual charges contribute some effect on the overall filtration performance of the R-PET/nano-PLA mat. A new way of simple curved micro-PET fiber combining with nano-scale fibers provides an industrial available path to mass production of high efficiency filtration material serving for air pollution control without electret process.