Dual Particle-Specie Concept for Improved Electrostatic Deposition Through Space-Charge Field Enhancement

A method is developed for enhancing the space-charge deposition of airborne particulates within electrostatically shielded target systems. Upon uniform dispersion of an active specie of particulate along with an inert specie within the target confines, differential electrical migration velocities can be effected to assure preferential deposition of all particles of the active specie before depletion of the interspersed cloud's space-charge field. Theoretical equations provide for judicious selection of relative application volumes and particle radii for the two distinct species. The model shows, for example, that when utilized for agricultural pesticide spraying of the interior regions of plant canopies, all toxic pesticide droplets can be electrostatically deposited prior to a 35-percent depletion of the cloud's space-charge field if a) at least 80 percent as much inert spray is dispersed along with the toxic spray, and b) if the toxic-to-inert specie radii ratio is ≥ 5. For this specific example of pesticide application, poor deposition of the remaining inert spray under electric-field depletion conditions would be of neither economic nor ecological consequence. The method is also applicable to numerous industrial uses in which space-charge generates the dominant force field for removal of particulate material out of air or other gas streams (e.g., fugitive dust control, precipitation of air-polluting emissions, resource recovery, etc.).