This thesis presents the mechanisms of IES and its applications to environmental and industrial processes. From the study of microbubble formation under IES, it was shown that bubble size in water could be reduced to 50 μm from an original size of about 1.5 mm. The use of microbubbles generated from IES is demonstrated in the ozonation of water and wastewater treatment processes. The mass transfer enhancement of ozone into water was shown by experiments and modeling.; A basic study of the mechanisms of IES showed that the electric stress and electrohydrodynamic (EHD) flow near the tip of the capillary are two key mechanisms of IES. The electric stress is a dominant mechanism at low-applied voltages whereas EHD flow dominates at high-applied voltages. Although the distinction between the two mechanisms is unclear, it was proven that EHD flow alone could not produce the spraying of microbbubles. However, it was found that EHD flow is responsible for the pressure break point and consequent EHD pumping in the reactor. The EHD pumping in IES is a novel phenomenon. Simultaneous spraying, mixing, and pumping by EHD flow is studied in depth. IES also produces corona discharge at high-applied voltages. Corona discharge produces ozone and radical species such as hydroxyl radical and aqueous electrons. The removal of organic contaminants using these radical species is a preferred method because radical species have stronger oxidation capability than any other oxidants. The use of the corona discharge process is demonstrated in the production of ultrapure water using phenol and methylene blue as the target organics. It was shown that corona discharge alone can be comparable to the ozonation process in organics removal. Also, as a preliminary study of the contaminated soil remediation, the ozone-soil interaction is studied both experimentally and numerically.
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