scholarly journals A Sustainable Recycling Alternative: Electrospun PET-Membranes for Air Nanofiltration

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1166
Author(s):  
Daniela P. F. Bonfim ◽  
Fabiana G. S. Cruz ◽  
Rosario E. S. Bretas ◽  
Vádila G. Guerra ◽  
Mônica Lopes Aguiar
Keyword(s):  
Indoor Air ◽  
Collection Efficiency ◽  
Mechanical Resistance ◽  
High Porosity ◽  
Air Filter ◽  
Aerosol Nanoparticles ◽  
Plastic Materials ◽  
Electrospun Membranes ◽  
Clean Air ◽  
Face Velocity

Currently, the inappropriate disposal of plastic materials, such as polyethylene terephthalate (PET) wastes, is a major environmental problem since it can cause serious damage to the environment and contribute to the proliferation of pathogenic microorganisms. To reduce this accumulation, PET-type bottles have been recycled, and also explored in other applications such as the development of membranes. Thus, this research aims to develop electrospun microfiber membranes from PET wastes and evaluate their use as an air filter media. The solution concentrations varied from 20 to 12% wt% of PET wastes, which caused a reduction of the average fiber diameter by 60% (from 3.25 µm to 1.27 µm). The electrospun filter membranes showed high mechanical resistance (4 MPa), adequate permeability (4.4 × 10−8 m2), high porosity (96%), and provided a high collection efficiency (about 100%) and low-pressure drop (212 Pa, whose face velocity was 4.8 cm/s) for the removal of viable aerosol nanoparticles. It can include bacteria, fungi, and also viruses, mainly SARS-CoV-2 (about 100 nm). Therefore, the developed electrospun membranes can be applied as indoor air filters, where extremely clean air is needed (e.g., hospitals, clean zones of pharmaceutical and food industry, aircraft, among others).

scholarly journals Multi-Scale Microstructure Investigation for a PM2.5 Air-Filter Efficiency Study of Non-Woven Polypropylene

2019 ◽  
Vol 3 (4) ◽  
pp. 20 ◽  
Author(s):  
Tu-Ngoc Lam ◽  
Chen-Hsien Wu ◽  
Sheng-Hsiu Huang ◽  
Wen-Ching Ko ◽  
Yu-Lih Huang ◽  
...  
Keyword(s):  
Particle Size ◽  
Collection Efficiency ◽  
Three Dimensional ◽  
Fiber Surface ◽  
Filter Material ◽  
Particle Size Range ◽  
Air Filter ◽  
Geometrical Properties ◽  
Multi Scale ◽  
Face Velocity

A N95 face-piece respirator and a 3M air filter composed of non-woven polypropylene filter material were investigated for their multi-scale microstructure and resulting filtration performance. Filtration mechanisms of each system are found and quantified. Both media showed a gradually decrease of the most penetrating particle size with respect to an increase in face velocity or surface charge density. Increasing the face velocity and porosity dramatically degraded the collection efficiency in the 3M filter rather than in the N95 system. We exploited three-dimensional X-ray tomography to characterize the morphological and geometrical properties of the fiber arrangement and deposition of aerosol on the fiber surface. Tuning the most predominant material parameters to achieve a precedence in lower pressure drop or higher collection efficiency in a specifically captured particle size range is of great requisite to a peculiar application of the filter media.

Ceramic Barrier Filters for Coal-Fueled Gas Turbine Service

1991 ◽  
Author(s):  
M. D. Stephenson ◽  
L. H. Cowell ◽  
R. T. LeCren
Keyword(s):  
Gas Turbine ◽  
Collection Efficiency ◽  
Performance Standards ◽  
Particulate Emissions ◽  
X Rays ◽  
X Ray Diffraction ◽  
Time Profiles ◽  
Exposure Testing ◽  
Face Velocity ◽  
Point Bend

Solar Turbines is developing a coal fueled version of its 3.8 MW Centaur H gas turbine for cogeneration applications. To protect gas turbine components from erosion and corrosion due to impacting particulates, and to meet New Source Performance Standards for particulate emissions, ceramic barrier filters are being employed. The test program includes evaluation of silicon carbide candle filters. Fourteen candles are being tested for 50 h at design temperature and face velocity using the particulate-laden gas stream from a two-stage slagging combustor system. The testing includes determining collection efficiency and obtaining pressure drop versus time profiles. Additionally, exposure testing is being used to determine whether loss in strength, or changes in the chemical or mineralogical structure have occurred. This includes four-point bend testing, X-ray diffraction and scanning electron microscopy with energy dispersive X-rays.

scholarly journals Creating Clean Air Spaces During Wildland Fire Smoke Episodes: Web Summit Summary

2021 ◽  
Vol 9 ◽  
Author(s):  
Gilliane Davison ◽  
Karoline K. Barkjohn ◽  
Gayle S. W. Hagler ◽  
Amara L. Holder ◽  
Sarah Coefield ◽  
...  
Keyword(s):  
Public Health ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Wildland Fire ◽  
Air Filtration ◽  
Wildfire Smoke ◽  
Fire Smoke ◽  
Clean Air ◽  
Pollution Events

Effective strategies to reduce indoor air pollutant concentrations during wildfire smoke events are critically needed. Worldwide, communities in areas prone to wildfires may suffer from annual smoke exposure events lasting from days to weeks. In addition, there are many areas of the world where high pollution events are common and where methods employed to reduce exposure to pollution may have relevance to wildfire smoke pollution episodes and vice versa. This article summarizes a recent virtual meeting held by the United States Environmental Protection Agency (EPA) to share research, experiences, and other information that can inform best practices for creating clean air spaces during wildland fire smoke events. The meeting included presentations on the public health impacts of wildland fire smoke; public health agencies' experiences and resilience efforts; and methods to improve indoor air quality, including the effectiveness of air filtration methods [e.g., building heating ventilation and air conditioning (HVAC) systems and portable, free-standing air filtration systems]. These presentations and related research indicate that filtration has been demonstrated to effectively improve indoor air quality during high ambient air pollution events; however, several research questions remain regarding the longevity and maintenance of filtration equipment during and after smoke events, effects on the pollution mixture, and degree to which adverse health effects are reduced.

scholarly journals Separation and Disinfection of Contagious Aerosols from the Perspective of SARS-CoV-2

Separations ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 190
Author(s):  
J. J. H. Brouwers
Keyword(s):  
Indoor Air ◽  
Service Time ◽  
Particle Number ◽  
Random Distribution ◽  
Particle Removal ◽  
Virus Particles ◽  
Number Distribution ◽  
Clean Air ◽  
Particle Separator ◽  
Droplet Nuclei

An assessment was performed on methods of separating and disinfecting airborne droplet nuclei containing viruses, such as SARS-CoV-2. The droplet nuclei originate from evaporating aerosols emitted by the coughing, singing, sneezing, etc. of infected humans. Based on empirical data and theoretical analysis, we successively determined: (i) the particle number distribution of nuclei versus the nucleus diameter, (ii) the statistical distribution of the viral content in the droplet nuclei starting from a uniform random distribution of viruses in the mucus, (iii) the particle number distribution of droplet nuclei containing at least one virus particle, and (iv) the effectiveness of methods for removing and disinfecting nuclei containing one or more virus particles from indoor air; viz., ventilation with fresh air, filtering with porous media, such as HEPA, and centrifugal separation and simultaneous disinfection, particularly with a rotational particle separator (RPS). Indoor aerosol removal with RPS supplemented with HEPA to arrest tiny volumes of very small particles was found to be the most effective. It is as good as particle removal through ventilation with clean air over long periods of time. An RPS facilitates direct elimination of viruses in the collected nuclei by flushing with a disinfection liquid. The components of an RPS are recyclable. Combining HEPA with an RPS extends the service time of HEPA by almost two orders of magnitude compared to the relatively short service time of stand-alone HEPA filters.

scholarly journals Evaluation of Air Filter Test Methods

1965 ◽  
Author(s):  
James W. May
Keyword(s):  
Test Methods ◽  
Test Method ◽  
Atmospheric Dust ◽  
Air Filters ◽  
Air Filter ◽  
Air Stream ◽  
Clean Air ◽  
Filter Test

There are three generally accepted test methods in current use for determining the effectiveness of air filters used for the collection of atmospheric dust. These three methods are (a) weight, (b) dust spot, and (c) DOP, which uses dioctyl-phylate as the aerosol. These test methods are discussed briefly and illustrations are used to assist the reader in visualizing the concentration of dust which will remain in the clean-air stream for efficiency values reported by each test method.

scholarly journals Enhancing indoor air quality –The air filter advantage

Lung India ◽  
2015 ◽  
Vol 32 (5) ◽  
pp. 473 ◽  
Author(s):  
VannanKandi Vijayan ◽  
Haralappa Paramesh ◽  
SundeepSantosh Salvi ◽  
AlpaAnil Kumar Dalal
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Air Filter
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