Factors affecting photocatalytic degradation of Reactive Green-19 with CdO-TiO2 nanocomposite

Abstract

Cdo-TiO2 nanocomposites were synthesized by varying the molar ratio of CdO: TiO2 as 1:1, 1:2, and 2:1 using the sol-gel method. The pH value for all the CdO-TiO2 nanocomposites was controlled at two different values, pH-3 and pH-13. The nanocomposites were used for facilitating photolytic degradation of azo dye (Reactive Green-19). 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-3 showed rod-like structure and some irregular shapes, while those synthesized at pH-13 were spherical. From XRD patterns, composites at pH-3 and pH-13 were crystalline; however, those at pH-3 were more crystalline. The parameters, namely initial dye concentration, pH of dye solution, and catalyst concentration, affecting photocatalytic activities were examined and optimized at 75 ppm, pH-7.5, and 1g/L, respectively. The progress of the degradation process of Reactive Green-19 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 A1:1 (The nanocomposites obtained at pH-3 with 1:1 mol% of CdO:TiO2) showed maximum degradation (94.53 %) at a catalyst concentration of 1 g/L.

Keywords

• precursors
• xrd
• peaks
• light intensity
• morphology
• chemical stability