Ball milling synthesis of ZnO/α-Fe2O3 nanocomposite as a photocatalyst for degradation of indigo carmine dye.

ZnO/α-Fe2O3 nanocomposite have been synthesized by a ball milling technique and applied for indigo carmine dye degradation in aqueous solutions. ZnO and α-Fe2O3 with the mole ratio of 1 : 5 were mixed without solvent in a planetary mill at the milling speed of 350 rpm for 2 h. X-ray Diffraction (XRD) and Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS) were used to characterize individual and nanocomposite samples. Based on XRD results it is known that the average crystallite size of α-Fe2O3, ZnO, and ZnO/α-Fe2O3 nanocomposite determined by using Scherer's formula are 52.40 nm, 39.47 nm, and 47.07 nm. SEM images show that α-Fe2O3 particles are highly homogeneous in shape and size, while the image of ZnO/α-Fe2O3 nanocomposite confirmed the presence of ZnO in α-Fe2O3 surface. Compare to α-Fe2O3 and ZnO, ZnO/α-Fe2O3 nanocomposite showed higher photocatalytic activitiy for degradation of indigo carmine under UV irradiation. Some parameter conditions such as the pH of indigo carmine solution, ZnO/α-Fe2O3 nanocomposite dosage, and indigo carmine concentration also studied in detail. The highest degradation percentage of indigo carmine was obtained by using 250 mg of ZnO/α-Fe2O3 nanocomposite, the initial pH of indigo carmine solution is 1, and indigo carmine concentration is 15 mg/L at the irradiation time under UV light for 120 minutes and 90 minutes under solar light. [ABSTRACT FROM AUTHOR]