α-Fe2O3 co-precipitation synthesis: evaluating the role of hydrogen peroxide as oxidizing agent in the photocatalytic degradation of atrazine

This study investigates the photocatalytic degradation of Atrazine, utilizing α-Fe₂O₃ synthesized through co-precipitation with and without the addition of hydrogen peroxide (H2O2). The α-Fe₂O₃ nanoparticles were characterized using various techniques, including UV–Visible spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM–EDX), X-ray Diffraction (XRD) spectroscopy, and Thermal Gravimetric Analysis (TGA), which confirmed the high purity of α-Fe₂O₃ nanoparticles with a crystallite size of ~ 30.2 nm and FTIR analysis reviewed at vibrational band at 516 and 642 cm–1indicating Fe–O vibrational stretching confirming the successful synthesis of the photocatalyst. The effects of herbicide concentration, α-Fe₂O₃ dosage, pH, time, and presence of inorganic ions on the degradation rates of the herbicide were assessed to evaluate the optimal conditions for the degradation process. The peak degradation (about 90%) was observed at 20 ppm of atrazine, 0.06 g of Fe₂O₃, and at neutral pH. H₂O₂ significantly enhanced degradation, particularly by reducing electron–hole recombination and promoting reactive oxygen species generation. Kinetic studies showed that atrazine degradation followed second-order kinetics, with a higher rate constant in the presence of H2O2 (2.507 × 10⁻4 mg⁻1·L·min⁻1) compared to its absence (1.681 × 10⁻4 mg⁻1·L·min⁻1). Cytotoxicity tests on HepG2 cells confirmed that the degradation products formed in the presence of H₂O₂ were completely non-toxic (0.00 ± 0.00%), in contrast to moderate toxicity from untreated atrazine. These results highlight that α-Fe₂O₃, especially when combined with H₂O₂, is an effective and environmentally safe photocatalyst for atrazine removal. The study suggests that the application of this system will advance water treatment technologies for effective detoxification of persistent herbicides.