Preparation of TiO2/SiO(x) double-layer films on glass beads and its application to NO and SO2 removal

Glass beads were coated with SiO(x) thin film as the first layer and with TiO2 thin film as the second layer by a rotating cylindrical PCVD reactor. The thicknesses of TiO2/SiO(x) double-layer films were measured by scanning electron microscopy. Glass beads coated with TiO2/SiO(x) double-layer films were packed inside the cylindrical reactor. NO and SO2 removal by dielectric barrier discharge-photocatalyst (DBD-P) hybrid process was tested for various conditions of process variables. The NO and SO2 removal efficiencies were improved by using a combination of dielectric barrier discharge and photodegradation by TiO2/SiO(x) double-layer films. The stronger the applied voltage is, the higher the pulse frequency is, or the longer the gas residence time is, the higher the NO and SO2 removal efficiencies become. In this study, we found that the glass beads coated with TiO2/SiO(x) double-layer films by a rotating cylindrical PCVD reactor could be used effectively to remove NO and SO2 by DBD-P hybrid process.