Síntese verde e caracterização de óxidos de ferro com extrato de folhas de syzygium cumini para aplicações fotocatalíticas

Abstract

The growing concern over environmental impacts drives the search for sustainable solutions in materials science, particularly in the development of clean technologies for wastewater treatment. In this context, the present study focused on the green synthesis of hematite (α-Fe¢O£) nanoparticles, both pure and doped with metal ions, using Syzygium cumini leaf extract as a reducing and stabilizing agent. This approach aligns with green chemistry principles, offering an eco-friendly synthesis route free of toxic reagents and with potential application in heterogeneous photocatalysis for the degradation of organic pollutants, such as methylene blue dye, in wastewater. The main objective was to develop and characterize α-Fe¢O£-based photocatalytic semiconductors and evaluate their optical and electrical properties. S. cumini leaves were collected and processed to obtain the plant extract, which was used to synthesize pure and doped α-Fe¢O£ with cerium (Ce) and nickel (Ni). The samples were characterized by X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). XRD confirmed the formation of the hematite crystalline phase, with characteristic crystallographic planes, while FTIR revealed bands associated with the plant extract's functional groups and iron oxides, along with signals related to the metallic dopants, indicating structural changes in the modified samples. The photocatalytic activity tests showed that the doped samples exhibited higher efficiency in degrading methylene blue under visible light compared to the undoped sample, suggesting that Ce and Ni doping enhanced charge separation and improved photocatalytic performance. Therefore, the results demonstrate the feasibility of a biosynthetic route using S. cumini as a green alternative for producing advanced nanomaterials with significant performance in water decontamination. This study contributes to the development of sustainable and innovative strategies for environmental remediation, combining science, technology, and ecological responsibility