Ozonation of soluble organics in aqueous solutions using microbubbles

This work investigates ozonation of a mixture of benzene, toluene, ethylbenzene, and xylenes (BTEX) dissolved in aqueous solutions having salt concentrations ranging from 0 to 2 M. The effect of microbubbles on the ozonation rate is examined. Microbubbles are formed either by an electrostatic spraying method or by a small-pore bubble diffuser. Although electrostatic spraying is effective for BTEX removal in low-conductivity solutions, results indicate it is not suitable for microbubble formation in high-ionic-strength solutions due to high electric current. In contrast, the bubble-diffuser method proved to be very effective in producing small bubbles in high-ionic-strength solutions. The production of small bubbles makes it possible to mitigate the mass transfer limitation, which has been shown to be the primary restriction in ozonation systems. When a bubble diffuser is employed, the removal rate of BTEX from simulated seawater is approximately twice that obtained with a simple capillary tube.