Photocatalytic degradation of methylene blue dye with biosynthesized Hematite α-Fe2O3 nanoparticles under UV-Irradiation

Abstract

Nanoparticles (NPs) are currently extensively utilized in various fields, such as medicine, solar energy, water treatment, and pollution detection. In this study, hematite (α-Fe2O3) NPs were synthesized using a cost-effective and environmentally friendly method involving the utilization of a biomass filtrate of Mentha pulegium as a bio-reducer. The structural and optical properties of the α-Fe2O3 NPs were investigated using techniques such as X-ray diffraction (XRD), UV-Visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). X-ray diffraction analysis confirmed the crystalline nature of the α-Fe2O3 NPs, with a crystallite size ranging from 16.92 to 35.38 nm. The α-Fe2O3 NPs exhibited absorption at 290 nm, indicating a direct bandgap ranging from 3.25 to 3.90 eV and an indirect bandgap of 2.69 to 3.59 eV, as determined from the UV-Visible spectra. FTIR analysis revealed a peak at 486 cm−1, attributed to the vibration of the α-Fe2O3 NPs, confirming the formation of the nanoparticles. SEM imaging showed that the green-synthesized α-Fe2O3 NPs generally exhibited a hexagonal shape. The efficiency of the biosynthesized α-Fe2O3 NPs was evaluated for the rapid degradation of Methylene Blue (MB) dye, achieving a degradation rate of up to 78% after 120 min. These findings could serve as a foundation for the development of highly effective photocatalytic degradation methods that may be employed in the future for the removal of hazardous dyes from contaminated water.