A study of ionization and collection efficiencies in electrospray-based electrostatic precipitators

Ozone-free electrostatic precipitators incorporating an array of electrospray wick charged aerosol ionization sources were built and tested. The particle ionization and collection efficiencies were independently measured for airborne particles as a function of air flow rate, electric field magnitude, and particle size. The results indicate that, while particle ionization efficiencies near 100% can be achieved using the electrospray ionization method, the number of elemental charges deposited onto a given particle depends strongly on the particle diameter and for submicron particles is very low. High overall particle collection efficiency, therefore, requires a carefully designed precipitation region where the maximum particle collection time, associated with the particles with the lowest mobility, is less than the residence time within the collector.