Electrostatic Enhancement of Collection Efficiency of the Fibrous Filter Pretreated with Ionic Surfactants

Abstract

A study of the electrostatic enhancement of collection efficiency of filters pretreated with ionic surfactants has been carried out in controlled conditions with monodisperse aerosols. Cationic surfactant (dimethyl dioctadecylammonium bromide [DDAB]) and anionic surfactant (sodium oleate [SO]) were used to pretreat polypropylene fibrous filters as the positively and negatively charged filters, respectively. The effects of aerosol size, aerosol charge state, face velocity, aerosol type, and relative humidity (RH) were considered to elucidate their influence on the aerosol penetration. Results indicate that penetration through surfactant-pretreated filters was lower than that through untreated filters, and pretreatment of the filter with surfactant was observed not to affect the structure of the filter. The electrofieldmeter direct-measured the very clear electric field of filter when treating ionic surfactants. The results proved that pretreatment with surfactant caused filters to become charged. Comparing penetration through surfactant-pretreated filters with that through untreated filters with neutral aerosol, the penetration reduction factor of the surfactant-pretreated filters was in the range 1.3-2.2. Comparing aerosol penetration through the surfactant-pretreated filters with singly charged aerosol with that through untreated filters with uncharged aerosol indicates that the former decreases by a factor of 1.8 -48.8. The surface fiber charges of the DDAB-and SO-pretreated filters were calculated to be 2.02 ϫ 1 Ϫ10 C/m and Ϫ1.53 ϫ 10 Ϫ10 C/m. Moreover, the aerosol penetrations through the surfactant-pretreated filters increased with the face velocity. Surfactant-pretreated filters performed better against solid aerosol than against liquid aerosol. RH has no effect on aerosol penetration through the surfactant-pretreated filters. Regression equations for Coulombic and dielectrophoretic single-fiber efficiencies in terms of the dimensionless parameters could be fitted by the experimental measurements of surfactantpretreated filters in this work.

Measurement of Lung Phosphatidylcholines in Exhaled Breath Particles by a Convenient Collection Procedure

“…Ethical approval for collecting breath samples was obtained from the Stockholm Regional Ethics review board (2008/1347-31). Aerosol particles present in the exhaled breath pass through a mouthpiece and are subsequently collected on a polymer filter with a diameter of 30 mm inside the device . In addition, this filter is an electret material that contains electric charge.…”

“…Aerosol particles present in the exhaled breath pass through a mouthpiece and are subsequently collected on a polymer filter with a diameter of 30 mm inside the device. 44 In addition, this filter is an electret material that contains electric charge. During sampling, charged particles from exhaled breath were trapped in the filter by electrostatic interaction.…”

Slip-Effect Functional Air Filter for Efficient Purification of PM2.5

“…A recent report from the United States Environmental Protection Agency has shown that 2.1 million deaths are incurred every year due to the rising concentrations of PM 2.5 worldwide 5 . Therefore, to eliminate PM 2.5 from polluted air, various technologies including electrostatic precipitation 6 7 8 and electrostatic enhanced fiber filtering 9 , have been exploited. Both of these techniques can effectively adsorb particles due to fortissimo electrostatic force.…”

A Review and CFD Case Study: The Effect of Temperature, Humidity, Aerodynamics on Corona Virus Transmission, Mitigation in Open and Enclosed Environments

“…[38] conducted observations in multiple university buildings in Coventry and Edinburgh. The general conclusion from the study taken in Coventry and Edinburgh infers that the comfort temperature of the lecture rooms were 22°C and 23°C for the studios within the universities when RH of 85% and air speeds of 2m/s at both universities [38][39][40].…”

“…Applying materials like what is used in N95 masks were the electrostatic charge increases the efficiency of the filtration could allow for further intervention to controlling and maintain the charge if it was housed within a system. From the work of [39] that informs and demonstrates this phenomenon of electrostatics in N95 mask material which is a waterproof polyester fabric, other options are also available. Production of a system that can maintain the integrity of the filter via maintaining the electrostatic effect and eliminating virus particles regular would produce a clean and efficient system to minimise recirculation of virus particles.…”