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

• DOI: 10.1007/s11664-019-07056-2
• Publication Date: 2019-02-21T16:50:53Z
• Authors: Xuan Hoa Vu; Luong Huu Phuoc; Nguyen Dac Dien; Thi Thu Ha Pham; Luong Duy Thanh
• Keywords: Methylene blue; Absorbance; Hydrothermal Synthesis; Ultraviolet visible spectroscopy

Well-crystalline iron oxide (α-Fe2O3) nanospindles have been prepared using a simple hydrothermal process at temperature of 240°C for different durations (24 h, 36 h, 48 h, and 60 h). 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 α-Fe2O3 with rhombohedral crystal structure. The photocatalytic activity of the obtained α-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 $$ \cdot {\hbox{OH}} $$ and $$ \cdot {\hbox{O}} $$ radicals played a crucial role in the degradation process of methylene blue. The α-Fe2O3 nanospindles presented high photocatalytic activity towards MB with degradation efficiency of 78% within 6 h of irradiation. These results demonstrate that α-Fe2O3 nanospindles are suitable for treatment of wastewater.