The combination effect of dielectric barrier discharge (DBD) and TiO2 catalytic process on styrene removal and the analysis of the by-products and intermediates

A wire-tube dielectric barrier discharge (DBD) reactor was established to treat styrene, which is a typical industrial pollutant with high toxicity and odorous smell, with TiO2 coated on the surface of the electrode and inner tube wall, respectively, by a simple and economic sol–gel method. The degradation and mineralization performance were comprehensively compared in the original reactor without TiO2 and in the reactor with TiO2 coated on the electrode and inner tube wall, respectively. As well as high catalytic efficiency, TiO2 also has high photocatalytic activity and can be excited by the energetic particles and ultraviolet radiation generated in the DBD reactor. Extra UV lamps were employed to verify the photocatalytic process in the presence of TiO2 during the reaction. The results showed that the degradation and mineralization efficiency obtained in the TiO2/inner tube wall reactor was much higher than that obtained in the TiO2/electrode reactor, and both of them were better than the original reactor. The types and the amounts of by-products during the reaction decreased in the order of the TiO2/inner tube wall reactor, the TiO2/electrode reactor, and the original reactor. The amounts of nitrogenous by-products and NO x decreased significantly in the reactors with the TiO2 coating, which indicated that the energy of the particles decreased in the presence of the high resistance TiO2 catalyst and scarcely destroyed N2, while improving the degradation and mineralization efficiency during the reaction.