Minimizing the size and ozone emission of electrostatic precipitators using dielectric and rolled carbon film coatings

Electrostatic precipitators (ESPs) are widely used to control air pollution. However, their applications in portable air cleaners are limited owing to ozone generation during the discharging process. In this study, we developed a compact two-stage ESP that combines corona discharging and particle collection modules. The former generates an extremely small amount of ozone using dielectric film coating, whereas the latter has a large specific surface area. A polypropylene (PP) film is coated as a dielectric material on the ground electrode of the discharging module. The corona current is reduced by the PP film, which in turn reduces the ozone generation. The efficiency of atmospheric particle collection and ozone generation were evaluated by varying the flow rates and applied voltages of the 4-channel discharging and roll-type collection modules. Additionally, the specific surface area of 707 m2/m3 of the roll-type collection module minimized the size of the device by increasing its integrity. The proposed ESP with PP coating exhibited the tendency of a conventional ESP that follows the Deutsch equation. All particles of size over 1 m were removed from the atmosphere by the proposed device at a flow rate of 194.4 L/min, which is more than three times that of human breathing. Furthermore, our experimental device removed more than 50% of the ultrafine particles of size 0.3 m without ozone generation. Therefore, the proposed device can be potentially used in portable or wearable air-cleaning devices to aid individual healthcare.