Effect of face velocity, nanofiber packing density and thickness on filtration performance of filters with nanofibers coated on a substrate

Leung, Wallace Woon‐Fong; Hung, Chi-Ho; Yuen, Ping-Tang

doi:10.1016/j.seppur.2009.10.017

Cited by 310 publications

(202 citation statements)

References 13 publications

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“…We hypothesize that the very low packing density of these PAN sheets was one reason for the high efficiency and relatively low pressure drop. This hypothesis is supported by the results reported by Leung et al (2010), who demonstrated that increasing the fiber packing density of electrospun mats can increase the pressure drop without significantly changing the filtration efficiency. Fotovati et al (2010) studied the effects of fiber orientation on the performance of aerosol filtration media and found that, for nanofiber filters, decreasing the in-plane orientation increased the quality factor.…”

Section: ¡1supporting

confidence: 77%

Polyacrylonitrile microscaffolds assembled from mesh structures of aligned electrospun nanofibers as high-efficiency particulate air filters

Kao

et al. 2016

Aerosol Science and Technology

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Electrospun polyacrylonitrile (PAN) fibers of very small diameters have potential for integration into filters capable of increasing the particle filtration efficiency. To fulfill the requirements for high-efficiency particulate air (HEPA) filters with a reasonable pressure drop, we generated aligned electrospun PAN fibers through pre-alignment at various rotation rates and subsequent solvent vapor annealing (SVA) under a loading. We evaluated the properties of microscaffold filters assembled from aligned electrospun PAN fibers in the form of linear, square, and triangular multiple meshes. The microscaffolds featuring multiple square meshes exhibited dramatically increased filtration efficiency without a significant pressure drop. A nine-layer cross-ply structure provided a filtration efficiency of 99.98% for 0.25-mm particles at a face velocity of 10 cm s ¡1 ; its filtration quality factor was the highest among all of the tested microscaffolds. Thus, HEPA filters featuring a low packing density can be achieved using PAN fibers.

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Section: ¡1supporting

confidence: 77%

Polyacrylonitrile microscaffolds assembled from mesh structures of aligned electrospun nanofibers as high-efficiency particulate air filters

Kao

et al. 2016

Aerosol Science and Technology

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“…The same principle applied to Filter B for the MPPS occurred at ~55 nm. These MPPSs were smaller than the previously reported results from building ventilation and vehicle cabin measurement studies (Xu et al, 2011;Podgórski et al, 2006;Leung et al, 2010). This is because the fiber solidity of aircraft cabin air filter is higher than the filters that are used in building ventilation or vehicle ventilation systems.…”

Section: Test Protocols and Data Analysiscontrasting

confidence: 62%

Investigation of the Performance of Airliner Cabin Air Filters throughout Lifetime Usage

Liu

Ren

et al. 2013

Aerosol Air Qual. Res.

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The air supply from an airliner ventilation system is a mixture of outside air and recirculated air that passes through a high efficiency particulate air (HEPA) filter. The effectiveness of two commercial-available airliner cabin air filters were investigated in laboratory-based measurements due to the practical restrictions on airliner cabin filter testing during usage. The filtration efficiency and pressure drop were assessed at a particle size range of 20-500 nm under various airflow rates throughout the filter usage period. The Most Penetrating Particle Sizes (MPPS) were observed at ~150 and ~55 nm, where the filtration efficiency was 86% and 99% at the rated airflow rates (1600 m 3 /h and 1970 m 3 /h), respectively. The filtration efficiency decreased in response to the increased airflow rate from 1000 m 3 /h to 2200 m 3 /h, with the greatest reduction (~10%) occurring at MPPS. An increase of 250 Pa in the pressure drop across the filter was observed as the airflow rate increased from 1000 m 3 /h to 2200 m 3 /h. Increased filter usage led to increases in both filtration efficiency and the pressure drop. The actual filter usage was estimated using dust loading in the laboratory. Filtration efficiency increased ~10% and the pressure drop increased ~800% when 220 g/m 2 dust was loaded on the filer, corresponding to ~6000 hours filter usage at an in-cabin PM 10 concentration of 100 μg/m 3 . Explicit relationships among filtration efficiency, pressure drop and filter usage under various in-cabin particle concentrations are presented as a reference to facilitate the use of more appropriate airliner cabin air filter exchange periods.

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“…Choi et al (2014) reported that the interception is a predominant collection mechanism in nanofiber filtration even for ultrafine particles, and its contribution increases with decreasing fiber diameter. Leung et al (2010) also reported that the coating of nanofiber on a substrate enhances the filtration efficiency and reduces the MPPS down to a smaller size of particles. The penetration of 300 nm particles at MF = 30% is 99.95% at the filtration velocity of 5 cm s -1 , which is close to the collection efficiency of HEPA filters.…”

Section: Filtration Performancementioning

confidence: 95%

Filtration Properties of Nanofiber/Microfiber Mixed Filter and Prediction of its Performance

Choi

Kumita

Hayashi

et al. 2017

Aerosol Air Qual. Res.

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There is an increasing demand of air filters with a high collection performance, i.e., high collection efficiency and low pressure drop, for the application to indoor air cleaning. Air filters consisting of nanofibers have attracted great interests since they may have a low pressure drop because of slip flow effect and high collection efficiency due to interception. Although various nanofiber filters are available on the market, their collection performance is not as high as expected by the conventional filtration theory because non-uniform packing of fibers plays a significant role. In the present work, the collection performance of nanofiber (780 nm) and microfiber (11.2 µm) mixed filters with various mixing fractions was studied in order to maximize the quality factor of filter, q F , as a function of mixing fraction of nanofibers. The collection performance of mixed fiber filters was predicted by using theoretical equations reported by Bao et al. (1998) for bimodal distribution of fibers. As a result, it was found that the mixed fiber filters had a uniform fiber packing compared to laminated filters and that the collection efficiency was well predicted by introducing the inhomogeneity factor calculated for the filter consisting of two distinct fiber sizes. Furthermore, we found that the mixed fiber filter with the nanofiber mixing fraction of 5% in mass had the highest quality factor.

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Effect of face velocity, nanofiber packing density and thickness on filtration performance of filters with nanofibers coated on a substrate

Cited by 310 publications

References 13 publications

Polyacrylonitrile microscaffolds assembled from mesh structures of aligned electrospun nanofibers as high-efficiency particulate air filters

Polyacrylonitrile microscaffolds assembled from mesh structures of aligned electrospun nanofibers as high-efficiency particulate air filters

Investigation of the Performance of Airliner Cabin Air Filters throughout Lifetime Usage

Filtration Properties of Nanofiber/Microfiber Mixed Filter and Prediction of its Performance

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