Factors affecting photocatalytic degradation of Reactive Green-۱۹ with CdO-TiO۲ nanocomposite

Cdo-TiO۲ nanocomposites were synthesized by varying the molar ratio of CdO: TiO۲ as ۱:۱, ۱:۲, and ۲:۱ using the sol-gel method. The pH value for all the CdO-TiO۲ nanocomposites was controlled at two different values, pH-۳ and pH-۱۳. The nanocomposites were used for facilitating photolytic degradation of azo dye (Reactive Green-۱۹). The surface morphology, crystallinity, and properties related to interactions with the light of the prepared catalyst were examined by scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and ultraviolet-visible (UV-Vis) spectrophotometer, respectively. The nanocomposites for all molar ratios synthesized at pH-۳ showed rod-like structure and some irregular shapes, while those synthesized at pH-۱۳ were spherical. From XRD patterns, composites at pH-۳ and pH-۱۳ were crystalline; however, those at pH-۳ were more crystalline. The parameters, namely initial dye concentration, pH of dye solution, and catalyst concentration, affecting photocatalytic activities were examined and optimized at ۷۵ ppm, pH-۷.۵, and ۱g/L, respectively. The progress of the degradation process of Reactive Green-۱۹ was observed by monitoring the change in the concentration of the dye after a certain time interval by measuring the absorbance by UV-Vis spectrophotometer. Catalyst A۱:۱ (The nanocomposites obtained at pH-۳ with ۱:۱ mol% of CdO:TiO۲)  showed maximum degradation (۹۴.۵۳ %) at a catalyst concentration of ۱ g/L. 

Keywords:

Precursors , XRD , Peaks , light intensity , morphology , chemical stability