Caesalpinia bonduc seeds assisted biosynthesis of Fe/ZnO photo-catalyst for degradation of methyl orange dye in aqueous medium

Abstract

Abstract The photocatalytic degradation of organic dyes has emerged as an efficient approach for wastewater treatment. In this study, Fe-ZnO nanocomposites (NCPs) were synthesized using extracts from the Caesalpinia bonduc seeds, a renewable and eco-friendly source. The synthesized NCPs were found to exhibit remarkable photocatalytic activity towards the degradation of methyl orange (MO) dye, a commonly used textile dye. Characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), Thermogravimetric Analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR), to confirm the successful synthesis of the nanocomposites. The photocatalytic degradation of methyl orange dye was investigated under visible light irradiation with a wavelength range of 400–700 nm. The results exhibited an impressive 90% reduction in the concentration of the methyl orange (MO) dye within 120 minutes of reaction time. Thorough investigations were conducted to assess the impact of various reaction parameters such as the catalyst loading, initial dye concentration, and the effect of hydroxyl radical scavengers to investigate the reaction kinetics and the degradation mechanism of MO dye. Moreover, the reusability and stability of the Fe-ZnO nanocomposites were evaluated, demonstrating their capability for practical applications in wastewater treatment. The study highlights the advantageous utilization of Fe-ZnO nanocomposites, synthesized through an environmentally benign green chemistry technique utilizing C. bonduc seed extracts. These nanocomposites serve as efficient and reusable catalysts for the photocatalytic degradation of methyl orange dye, thereby contributing to the advancement of eco-friendly and cost-effective solutions for treating textile wastewater.