Single-phase membrane ozonation of hazardous organic compounds in aqueous streams

The use of ozone to treat hazardous organic wastes in water is limited by the low solubility of ozone in water. The use of semipermeable nonporous silicone capillary membranes to transfer ozone nondispersively into an aqueous phase and ozonate organic species has been studied for the single pollutants phenol, nitrobenzene and acrylonitrile. Preliminary experimental results are presented here to demonstrate the efficacy of such a process using silicone capillary membranes. The substantially larger a (surface area per unit volume of device) (15.3 cm²/cm³ in the case of module 2) that this membrane ozonator provides leads to a significantly larger value of mass transfer parameter compared to those in conventional equipments. For iodometric consumption of ozone, the value of k_la in presence of reaction was found to be 5.8 × 10^-3 s^-1 in module 2 compared to calculated values of 1.058 × 10^-3 s^-1 for a packed column containing Raschig rings 1.3 cm in size and 3.22 × 10^-4 s^-1 for a bubble column operating under comparable superficial gas and liquid velocities.