Effect of Pleat Structure on the Air Purification Performance of a Polytetrafluoroethylene/Poly(ethylene terephthalate) Composite Membrane Filter

Cartridge structure has a significant impact on the filtration performance of membrane filters during air purification. A clear understanding of the structure-function relationship of filter cartridges is important for improving their performance in air purification through a rational structure design of filter cartridges. In this work, the effects of pleat height and pleat pitch on the filtration efficiency and resistance of a poly(tetrafluoroethylene)/poly(ethylene terephthalate) (PTFE/PET) composite membrane filter were studied by a combination of experimental tests and computational fluid dynamics simulation. The fouling mechanism of the PTFE/PET composite membrane filter was investigated. The results showed that the PTFE/PET composite membrane filter cartridge with a 55 mm pleat height and 3 mm pleat pitch had the lowest filtration resistance (112 Pa) and the highest filtration efficiency (99.95%). The PTFE/PET composite membrane filter was able to keep the particulate matter at the outlet side of the filtration system below 10 μg·m^-3 during a 90-day purification cycle. In addition, the membrane fouling was mainly attributed to the pore blockage caused by the dust particles (soluble/insoluble: 23.67:76.33%) smaller than 1 μm. The findings of this work provide guidance on the structural design and optimization of pleat filters pertaining to air purification systems.