Size reduction of Aspergillus versicolor fungal bioaerosols during a thermal heating process in continuous-flow system

Jung, Jae Hee; Lee, Jung Eun; Kim, Sang Soo; Bae, Gwi Nam

doi:10.1016/j.jaerosci.2010.03.004

Cited by 11 publications

(5 citation statements)

References 43 publications

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“…For the thermal drying process, we used a thermal electric heating system, consisting of a quartz tube (inner diameter, 29 mm; length, 700 mm; thickness, 1 mm) and an electric heating controller To prevent obstruction of the nanoparticle flow through the thermal tube, the heating coils were located outside the quartz tube and covered with insulating materials. Details of the thermal electric heating system and its center temperature distribution have been reported previously (Jung et al 2009a(Jung et al , 2009c(Jung et al , 2010. The drying temperature used was 200 • C (maximum) and the residence time of the airflow between the inlet and outlet of the quartz tube was about 1.4 s.…”

Section: Nebulization-thermal Drying Systemmentioning

confidence: 99%

Antimicrobial Air Filtration Using AirborneSophora FlavescensNatural-Product Nanoparticles

Jung

Hwang

Park

et al. 2011

Aerosol Science and Technology

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We investigated nanoparticle generation from a natural plant extract using the aerosol technique of the nebulization-thermal drying process, and tested its usefulness for antimicrobial air filtration. Sophora flavescens Ait. ethanolic extract was prepared as an antimicrobial natural-product suspension. Suspension droplets were generated using a single-jet Collison nebulizer, passed through an active carbon absorber to remove ethanol, and mixed and dried with sheath air. For drying, natural-product particles were exposed to 200 • C for ∼1 s. Finally, particles were introduced into a scanning mobility particle sizer, and their size distribution and morphology were analyzed. For application of natural-product particles to antimicrobial air filtration, the nanosized particles generated were deposited continuously onto air filter medium at various times. Physical characteristics (filtration efficiency, pressure drop, and fiber morphology by scanning electron microscopy), and biological characteristics (antimicrobial tests against Staphylococcus epidermidis, Bacillus subtilis, and Escherichia coli bioaerosols) were then evaluated. We also analyzed the chemical composition of particles deposited on the filter surface. The results showed that the nanoparticles generated were spherical and demonstrated a polydisperse size distribution, ranging from several tens to several hundred nanometers. Although the filter pressure drop increased with the amount of nanoparticle on the filter, the bioaerosol filtration efficiency and antimicrobial activity were enhanced. In particular, the S. flavescens natural-product nanoparticle-deposited filters were more effective for removal of Gram-positive than Gram-negative bioaerosols. These results are promising for the implementation of this new technology for control of air quality against hazardous bioaerosols.

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Section: Nebulization-thermal Drying Systemmentioning

confidence: 99%

Antimicrobial Air Filtration Using AirborneSophora FlavescensNatural-Product Nanoparticles

Jung

Hwang

Park

et al. 2011

Aerosol Science and Technology

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“…In order to improve air quality, many techniques including adsorption on carbon, 4 glass 5 and polymeric materials, 6 application of bioelectrochemical system, 7 photocatalytic degradation process, 8,9 condensation, membrane separation, 10 separation of VOCs using ionic liquids, 11 thermal oxidation process, and catalytic combustion 12 have been studied. Among them, photocatalytic oxidation is one of the most promising technique for air purification.…”

Section: Introductionmentioning

confidence: 99%

“…process, 8,9 condensation, membrane separation, 10 separation of VOCs using ionic liquids, 11 thermal oxidation process, and catalytic combustion 12 have been studied. Among them, photocatalytic oxidation is one of the most promising technique for air purification.…”

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confidence: 99%

Gas‐phase removal of indoor volatile organic compounds and airborne microorganisms over mono‐ and bimetal‐modified (Pt, Cu, Ag) titanium(IV) oxide nanocomposites

et al. 2019

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The photocatalytic deactivation of volatile organic compounds and mold fungi using TiO2 modified with mono‐ and bimetallic (Pt, Cu, Ag) particles is reported in this study. The mono‐ and bimetal‐modified (Pt, Cu, Ag) titanium(IV) oxide photocatalysts were prepared by chemical reduction method and characterized using XRD, XPS, DR/UV‐Vis, BET, and TEM analysis. The effect of incident light, type and content of mono‐ and bimetallic nanoparticles deposited on titanium(IV) oxide was studied. Photocatalytic activity of as‐prepared nanocomposites was examined in the gas phase using LEDs array. High photocatalytic activity of Ag/Pt‐TiO2 and Cu/Pt‐TiO2 in the reaction of toluene degradation resulted from improved efficiency of interfacial charge transfer process, which was consistent with the fluorescence quenching effect revealed by photoluminescence (PL) emission spectra. The photocatalytic deactivation of Penicillium chrysogenum, a pathogenic fungi present in the indoor environment, especially in a damp or water‐damaged building using mono‐ and bimetal‐modified (Pt, Cu, Ag) titanium(IV) oxide was evaluated for the first time. TiO2 modified with mono‐ and bimetallic NPs of Ag/Pt, Cu, and Ag deposited on TiO2 exhibited improved fungicidal activity under LEDs illumination than pure TiO2.

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“…Plasma air cleaners were also shown to be effective in microbial inactivation [18,19]. Other air cleaning technologies may also potentially emit ROS, including those using ceramics and transition metal oxides to adsorb and/or remove formaldehyde at room temperature [20,21] and those aimed at microbial inactivation at high temperatures [22][23][24]. The later involves combination with ceramic and zeolite substrates [25,26].…”

Section: •-mentioning

confidence: 99%

Detection and quantification of reactive oxygen species (ROS) in indoor air

Montesinos

Sleiman

Cohn

et al. 2015

Talanta

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Reactive oxygen species (ROS), such as free radicals and peroxides, are environmental trace pollutants potentially associated with asthma and airways inflammation. These compounds are often not detected in indoor air due to sampling and analytical limitations. This study developed and validated an experimental method to sample, identify and quantify ROS in indoor air using fluorescent probes. Tests were carried out simultaneously using three different probes: 2',7'-dichlorofluorescin (DCFH) to detect a broad range of ROS, Amplex ultra Red® (AuR) to detect peroxides, and terephthalic acid (TPA) to detect hydroxyl radicals (HO(•)). For each test, air samples were collected using two impingers in series kept in an ice bath, containing each 10 mL of 50 mM phosphate buffer at pH 7.2. In tests with TPA, that probe was also added to the buffer prior to sampling; in the other two tests, probes and additional reactants were added immediately after sampling. The concentration of fluorescent byproducts was determined fluorometrically. Calibration curves were developed by reacting DCFH and AuR with known amounts of H2O2, and using known amounts of 2-hydroxyterephthalic acid (HTPA) for TPA. Low detection limits (9-13 nM) and quantification limits (18-22 nM) were determined for all three probes, which presented a linear response in the range 10-500 nM for AuR and TPA, and 100-2000 nM for DCFH. High collection efficiency (CE) and recovery efficiency (RE) were observed for DCFH (CE=RE=100%) and AuR (CE=100%; RE=73%) by sampling from a laboratory-developed gas phase H2O2 generator. Interference of co-occurring ozone was evaluated and quantified for the three probes by sampling from the outlet of an ozone generator. The method was demonstrated by sampling air emitted by two portable air cleaners: a strong ozone generator (AC1) and a plasma generator (AC2). High ozone levels emitted by AC1 did not allow for simultaneous determination of ROS levels due to high background levels associated with ozone decomposition in the buffer. However, emitted ROS were quantified at the outlet of AC2 using two of the three probes. With AuR, the concentration of peroxides in air emitted by the air cleaner was 300 ppt of H2O2 equivalents. With TPA, the HO(•) concentration was 47 ppt. This method is best suited to quantify ROS in the presence of low ozone levels.

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Size reduction of Aspergillus versicolor fungal bioaerosols during a thermal heating process in continuous-flow system

Cited by 11 publications

References 43 publications

Antimicrobial Air Filtration Using AirborneSophora FlavescensNatural-Product Nanoparticles

Antimicrobial Air Filtration Using AirborneSophora FlavescensNatural-Product Nanoparticles

Gas‐phase removal of indoor volatile organic compounds and airborne microorganisms over mono‐ and bimetal‐modified (Pt, Cu, Ag) titanium(IV) oxide nanocomposites

Detection and quantification of reactive oxygen species (ROS) in indoor air

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