AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Investigation of an Optimized Single-Stage Electrostatic Precipitator for Bioaerosols
TAEWON HAN, Donna Fennell, Gediminas Mainelis, Rutgers, The State University of New Jersey
Abstract Number: 447 Working Group: Health Related Aerosols
Abstract We recently developed an electrostatic collector for bioaerosols, where biological particles are electrostatically deposited onto a 3.2 mm electrode covered by a hydrophobic substance and then removed and collected by rolling water droplets (20 or 40 micro-liter) to achieve high sample concentration rate. As part of the further development of the collector, it was integrated with a new electrical charger based on carbon fiber brushes. The new integrated sampler was made of static dissipative material (e.g., Delrin) and has a shape of a closed half cylinder. Its top round top part contains carbon fiber brushes, while its flat bottom holds a narrow collection electrode. The objective of this research was to optimize the charger and collection electrode for maximum performance of the sampler. We tested the sampler with various configurations of carbon brushes comprising the charger and different materials of the collection electrode. The total bioaerosol particles number collected by a water droplet was determined by microscopy and the reference concentration was monitored by a Grimm optical particle counter.
Surprisingly, electrode material had a great effect on collection efficiency: copper (19%), brass (30%), plain steel (46%), zinc plate steel and high carbon steel (50%), alloy steel (51%), stainless steel (79%), pressed carbon fiber (87%). A combination of the charger with eight carbon brushes and carbon fiber electrode yielded virtually no particle losses and collection efficiency of 84% when sampling E. coli bacteria at 10 L/min for 10 min. The efficiency was the same for 20 and 40 micro-liter droplets. When sampling for 60 min, the actual collection efficiency was 70% due to a reduced particle removal from the electrode. This bioaerosol sampler will be optimized for higher flow rates, but it already shows great promise and could be a part of various applications, including Homeland security.