Optimizing degradation of Reactive Yellow 176 by dielectric barrier discharge plasma combined with TiO2 nano-particles prepared using response surface methodology

Abstract

The central composite design (CCD) was applied to optimize the preparation conditions of nano-particle TiO2 photocatalysts in plasma catalysis system. The prepared TiO2 photocatalysts were used to degrade C.I. Reactive Yellow 176 (RY176) in combination with dielectric barrier discharge (DBD) plasma. Their photocatalytic activity was studied by degradation efficiency of RY176 in aqueous solutions. The individual and interactive effects of the four main independent parameters (molar ratio of acetic acid to titanium butoxide, molar ratio of water to titanium butoxide, calcination temperature and calcination time) on the photocatalytic activity of nano-TiO2 photocatalysts could be investigated by the CCD and the optimum value was found to be 2, 3.42, 577.60 °C and 3.25 h, respectively. The degradation efficiency of RY176 treated by DBD plasma combining nano-TiO2 (0.1 g/L) prepared under these preparation conditions was 83.54%, which was 17.33% higher than that of the value (66.21%) only treated by DBD plasma under same operation condition. The decrease of peak intensity in the UV–vis spectrum indicated that degradation of dye took place in plasma catalysis system. The XRD results showed that the TiO2 nano-particles prepared under the optimal conditions had a mixed crystal structure containing anatase phase (77.4%) and rutile phase (22.6%) and the particle size was 18.2 nm. SEM and TEM images defined the nanocrystalline nature of the prepared TiO2.