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

Abstract

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.

Long-Term Sampling of Viable Airborne Viruses

“…Most of the existing bioaerosol samplers utilize one of the following three collection methods: dry filtration, impaction onto a nutrient (e.g., agar), or impingement into a liq-uid. Although some other principles, such as electrostatic precipitation, have been also explored for bacteria (Mainelis et al 1999(Mainelis et al , 2002a(Mainelis et al , 2002b and viruses (Hogan et al 2004), the above three methods are primarily used in the field. Due to a strong desiccation effect and subsequent low microbial recovery, the dry filtration is not generally recommended for a long-term viable bioaerosol monitoring and is primarily used for the total (viable + non-viable) microorganism enumeration (Cox and Wathes 1995).…”

Capture of airborne nanoparticles in swirling flows using non-uniform electrostatic fields for bio-sensor applications

“…Various electrostatic collectors have also been developed to capture bioaerosols from airstreams [1][2][3]. These instruments have an advantage of being operated with a low-pressure drop.…”

“…[1][2][3][4]. Exposure to bioaerosols in indoor and outdoor environments may cause a wide range of health disorders, ranging from mild irritation to a serious disease.…”

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

“…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.…”