Photocatalytic Degradation of Methylene Blue (MB) over α-Fe2O3 Nanospindles Prepared by a Hydrothermal Route

Well-crystalline iron oxide (alpha-Fe2O3) nanospindles have been prepared using a simple hydrothermal process at temperature of 240 degrees C for different durations (24h, 36h, 48h, and 60h). The products were characterized by x-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, energy-dispersive x-ray spectroscopy, and visible absorption measurements. Detailed characterization of their structure and composition confirmed formation of pure alpha-Fe2O3 with rhombohedral crystal structure. The photocatalytic activity of the obtained alpha-Fe2O3 for demineralization of methylene blue (MB) in aqueous solution under ultraviolet (UV) light irradiation was evaluated. Ultraviolet-visible (UV-Vis) spectroscopy indicated a decrease in the absorbance intensity and concentration of the dye. Mechanistic investigation revealed that center dot OH and center dot O radicals played a crucial role in the degradation process of methylene blue. The alpha-Fe2O3 nanospindles presented high photocatalytic activity towards MB with degradation efficiency of 78% within 6h of irradiation. These results demonstrate that alpha-Fe2O3 nanospindles are suitable for treatment of wastewater.