Moringa Stenopetala (Shiferaw) Seed Extract Mediated Synthesis of ??-Fe2O3 Nanoparticle for Photocatalytic Degradation of Methylene Blue Dye

Abstract

Photocatalytic degradation of organic pollutants is an effective technology for the treatment of industrial wastewater. This study focused on the green synthesis of hematite nanoparticles using Moringa stenopetala seed extract for effective photocatalytic degradation of methylene blue dye under sunlight irradiation. Hematite (α-Fe2O3) NPs were synthesized via precipitation process with seed extract acting as a capping and reducing agent. The synthesized α-Fe2O3 nanoparticles were characterized using thermo gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible spectroscopy (UV-Vis), and Fourier transform infrared (FTIR) spectroscopy. TGA confirms the synthesized hematite nanoparticles were calcinated at 600 ºC. The XRD result confirmed the formation of a rhombohedral centered hexagonal structure of α-Fe2O3 NPs with an average crystallite size of 32.57 nm. From UV-Vis analysis, the appearance of the maximum peak at 313 nm and the calculated band gap energy of 2.744 eV highly confirm the development of α-Fe2O3 NPs. From the FT-IR data, the peak at 538 cm -1 indicates the formation of characteristic Fe-O bonds. The functional group responsible for the formation of α-Fe2O3 nanoparticles was revealed by Fourier transform infrared radiation. The photocatalytic application of α-Fe2O3 NPs for photocatalytic degradation of methylene blue dye using direct solar light irradiation. The degradation efficiency of 98.33% was achieved at pH 12, catalyst dosage of 0.05 gm, and 30 mg/L of dye at 90 minutes. The degradation efficiency of MB dye was varied with the pH of the solution, concentrations of dye, and dose of α-Fe2O3 NPs for a certain interval of time. The calculated chemical oxygen demand (COD) value indicates the elimination of the dye, and the recyclability experiment indicates the fabricated α Fe2O3 NPs have high stability and can be used for several times.