Synthesis of Ag nano/TiO2 by γ-irradiation and optimisation of photocatalytic degradation of Rhodamine B

The effect of Ag nano content in Ag nano/TiO2 materials was studied with regard to the photocatalytic degradation of Rhodamine B (RB) as a model pollutant from textile industry. Ag nano/TiO2 materials were prepared by gamma-irradiation method and characterised by X-ray diffraction (XRD), transmission electron microscopy (TEM) analysis and surface area measurement by Brunauer-Emmett-Teller (BET) method. At 1.5% Ag content, the Ag nano/TiO2 photocatalyst exhibited the highest visible light photocatalytic activity. Several influence factors of the RB degradation process such as the content of catalyst, the initial concentration of dye, the irradiation time and pH of the reaction mixture were also investigated. Design Expert software version 7 was used to optimise the effects of the experimental parameters on the responses. The results of experiments were fitted to two quadratic polynomial models developed using response surface methodology (RSM). The results showed that the predicted data from RSM are in good agreement with the experimental results with a correlation coefficient (R-2) of 0.9915. The maximum degradation efficiency (82.61%) was achieved at initial RB concentration: 10(-5) M, catalyst dosage: 1.44 g/L, irradiation time: 63.8 min and pH: 6.15.