Gaseous Electrical Discharge-Induced Degradation of Organic Compound in Wastewater: UV Irradiation and Ozonation Effect

Abstract

AbstractThis study investigated the degradation of an organic compound (an azo dye, Acid Red 4) in a synthetic wastewater by using dielectric barrier discharge (DBD) tube comprised of a hollow quartz cylinder and a coaxial copper rod. The DBD tube was immersed in the wastewater that was connected to the ground electrode. When AC high voltage was applied to the copper electrode, the electrical discharge occurred inside the quartz cylinder to produce ultraviolet (UV) light and reactive species such as ozone. The photocatalytic degradation of the organic compound with the UV emitted from the DBD tube was carried out in the presence of aluminum meshes coated with titanium oxide. The system further comprised a gas diffuser that distributed the ozone-containing gas produced in the DBD tube into the wastewater, such that the organic compound were degraded by reacting with ozone. The contributions of the photocatalysis and the ozonation to the degradation were separately assessed, and then combined effect on the degradation was examined. The results clearly revealed that the present system capable of degrading the organic compound in two ways (DBD-induced photocatalysis and ozonation) was very effective for the treatment of the wastewater.