Removal of diethyl phthalate from water by ozone microbubbles in a pilot plant.

Ozone microbubbles (OMBs) were used to remove diethyl phthalate (DEP) from water in a pilot plant. The removal of DEP and the mineralization efficiency were investigated under various reaction conditions. The removal of DEP by OMBs was very effective at the high pH and high ozone generation rates. Almost complete mineralization of DEP could be achieved at the high pH. The contribution of OH was computed by using a hydroxyl radical scavenger (i.e. t-BuOH). In neutral and alkaline media, the reaction of DEP with OH dominated over its direct reaction with ozone. The overall oxidation reaction fitted a second-order kinetic model. The overall rate constant and the volumetric mass transfer coefficient of ozone slightly increased with increasing pH. The results indicate that the OMBs were efficient in terms of the reduction of concentration of DEP and its complete mineralization.