Charging of particles in unipolar coronas irradiated by in-situ soft X-rays: enhancement of capture efficiency of ultrafine particles

Kulkarni, Pramod; Namiki, Norikazu; Ōtani, Yoshio; Biswas, Pratim

doi:10.1016/s0021-8502(02)00067-8

Cited by 62 publications

(68 citation statements)

References 20 publications

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“…However, due to the decrease in particle charge with decrease in size, and increase in the drag forces with increase in size, ESPs typically have a collection efficiency minimum in the submicrometersize region (Flagan and Seinfeld 1988). Though not predicted by conventional ESP models, the capture efficiency has also been found to decrease significantly as particle size decreases in the ultrafine particle size region (Watanabe et al 1995;Kim and Biswas 1996;Yoo et al 1997;Zhuang et al 2000;Kulkarni et al 2002). This decrease has been attributed to partial charging of ultrafine particles (Zhuang et al 2000).…”

Section: Introductionmentioning

confidence: 96%

Capture of Viral Particles in Soft X-Ray–Enhanced Corona Systems: Charge Distribution and Transport Characteristics

Hogan

Lee

Biswas

2004

Aerosol Science and Technology

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The charge distribution of airborne MS2 bacteriophage nanoparticles and the efficiency of electrical-mobility-based capture mechanisms with bipolar charging were studied. MS2 virions form large agglomerated particles in a suspension. The average charge on airborne MS2 virions can be as high as one unit charge (negatively charged). The application of both soft X-ray irradiation and alpha rays from a Po-210 bipolar charger was shown to not only reduce the average charge on MS2 virion particles but also partially fragment the larger MS2 virion agglomerates, thereby increasing the number of ultrafine MS2 virion particles. A cylindrical electrostatic precipitator with a mounted soft X-ray emitter was used to determine the effectiveness of electrical capture methods for virus particles. At low applied voltages, it was found that the capture efficiency of ultrafine virus particles can be increased by applying in situ soft X-ray irradiation with electrostatic precipitation. It has also been shown that in the presence of both a positive and negative corona, virus particles are readily captured with log removal values exceeding 4. The unit developed and demonstrated in this work is a compact, low-pressure drop system that can be readily mounted in ventilation ducts or air supply systems to remove ultrafine particles such as viruses.

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Section: Introductionmentioning

confidence: 96%

Capture of Viral Particles in Soft X-Ray–Enhanced Corona Systems: Charge Distribution and Transport Characteristics

Hogan

Lee

Biswas

2004

Aerosol Science and Technology

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“…It had a wire-cylinder geometry and could be energized with DC or DC coupled with pulsed voltages. The geometrical configuration was similar to those reported in other works (Kulkarni et al, 2002;Li et al, 2009) The high voltages were applied across the collecting and discharge electrodes with special designed generators. High DC voltages could be adjusted in the range of 0 to ± 10 kV.…”

Section: Bench-scale Pulse-energized Espmentioning

confidence: 82%

“…For the positive applied voltages, the efficiencies were 99.40% and 99.92%, respectively. Since in negative corona there are excess negative ions that have a higher electrical mobility than positive ions, the negative corona results in more effective diffusion charging in comparison to the positive case, leading to a better capture performance (Kulkarni et al, 2002). From Fig.…”

Section: Lpi Analysismentioning

confidence: 94%

“…In addition, several modified ESPs were also developed and reported in literature, such as electrostatic flocking (Sung et al, 2006), wet electrostatic precipitators (Saiyasitpanich et al, 2006), dielectric barrier discharge (Byeon et al, 2006), plasma enhanced precipitator (Montgomery et al, 2005), soft X-ray-enhanced corona systems (Kulkarni et al, 2002;Hogan et al, 2004;Jiang et al, 2007), simultaneous diffusional-electrostatic precipitation (Alonso et al, 2002), and pulse-energized electrostatic precipitation (Dinelli et al, 1991;Jayaram et al, 1996;Mok et al, 1999;Zukeran et al, 1999a;Liang et al, 2002a;2002b). Among the above methods, the pulse-energized ESPs may be considered as a retrofit option.…”

Section: Introductionmentioning

confidence: 99%

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Capture of Particles from an Iron and Steel Smelter with a Pulse-Energized Electrostatic Precipitator

Grigoriu

Wang

Martín

et al. 2012

Aerosol Air Qual. Res.

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A bench-scale pulse-energized electrostatic precipitator (ESP) was developed to study the capture of particles from exhaust gas streams from iron and steel factories. The morpho-structural characteristics, composition and size distribution of the particles were analyzed. The results showed that the particles consisted primarily of iron oxides and other compounds containing Ca, S, C, Si, Al, and Na elements. The particles had a broad size distribution ranging from 5 nm to several micrometers. The V-I characteristics of the ESP were studied with biased DC voltages of ± 10 kV and ± 10 kV with superimposed pulses (± 5.5 kV, rise time 60 ns, repetition rate 50 pps). The capture efficiency was investigated by means of a low pressure impactor and scanning mobility particle sizer. In the range of 155 to 6,650 nm, the ESP number-based capture efficiencies were > 99.6% and > 98.9% for negative and positive voltages, respectively. For sizes less than 50 nm, the negative pulsed mode was remarkably efficient (93.7 to 99.4%).

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“…To further improve the efficiency of charging nanoparticles, researchers have used direct irradiation methods such as Ultraviolet (UV) (Burtscher et al, 1982;Jung et al, 1988;Kogelschatz, 1992;Matter et al, 1995;Mohr et al, 1996;Mohr and Burtscher, 1997;Maisels et al, 2003;Hontañón and Kruis, 2008) and soft x-ray irradiation for nanoparticle charging (Kulkarni et al, 2002, Shimada et al, 2002Han et al, 2003;Jiang et al, 2007a). Under UV exposure, electrons can be emitted from the particle surface once irradiated, and irradiated particles thus become positively charged if the incident photon energy exceeds the particle material work function.…”

Section: Introductionmentioning

confidence: 99%

Aerosol Charging Using Pen-Type UV Lamps

Lin

Chen

2011

Aerosol Air Qual. Res.

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A portable aerosol charger utilizing pen-type Hg lamps was constructed to investigate the particle charging process under UV irradiation. The charger primarily consisted of a quartz tube surrounded by four pen-type low-pressure Hg lamps and an ion trap located downstream of the quartz tube to remove excessive ions. The performance of the prototype UV charger at 5 L/min flow rate and with four UV lamps turned on using monodisperse silver (Ag) particles with diameters ranging from 7 to 30 nm was evaluated. As expected, the prototype UV charger provided higher particle charging efficiencies than coronabased unipolar chargers for Ag particles. To evaluate the effect of irradiation intensity on particle photocharging, the charging efficiencies and charge distributions for Ag particles ranged from 7 to 30 nm when the prototype was operated at an aerosol flow rate of 5 L/min for the cases of one, two, and four lamps turned on. The UV charging model with the photoemission based on the Fowler-Nordheim law was further applied to predict the charging performance of the UV charger at different operational conditions.

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Charging of particles in unipolar coronas irradiated by in-situ soft X-rays: enhancement of capture efficiency of ultrafine particles

Cited by 62 publications

References 20 publications

Capture of Viral Particles in Soft X-Ray–Enhanced Corona Systems: Charge Distribution and Transport Characteristics

Capture of Viral Particles in Soft X-Ray–Enhanced Corona Systems: Charge Distribution and Transport Characteristics

Capture of Particles from an Iron and Steel Smelter with a Pulse-Energized Electrostatic Precipitator

Aerosol Charging Using Pen-Type UV Lamps

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