Green Synthesis of TiO₂ Nanoparticles Using Mango Leaf Extract: Phase Transformation and Photocatalytic Efficiency Across Calcination Temperatures
摘要
This research looks at how to make titanium dioxide (TiO₂) nanoparticles eco-friendly using mango (Mangifera indica) leaf extract. It examines how their structures and photocatalytic properties change when heated at different temperatures from 300 °C to 1000 °C. The biosynthesized nanoparticles were characterized using XRD, FTIR, EDX, and UV–Vis spectroscopy. XRD analysis showed that TiO₂ nanoparticles calcined at 300 and 500 °C largely exhibited the anatase phase, while the rutile phase started emerging at higher temperatures (700–1000 °C), demonstrating phase transformation due to temperature. The sample calcined at 500 °C demonstrated optimal crystallinity and low particle agglomeration. FTIR spectra confirmed that bonds of Ti–O-Ti were present, with the organic compounds being removed more easily at higher temperatures. EDX analysis narrowed down element purity, as strong signals indicative of titanium and oxygen were present with little impurities. Photocatalytic degradation experiments utilizing UV light and target pollutants, Malachite Green (MG), Rhodamine B (RhB), and real textile wastewater were done. The sample TiO₂-500 came out on top of all with 93.11% MG degradation, 95.15% RhB, and 83.25% textile, for TiO₂ with UV–Vis spectral monitoring revealing the absorption intensity declining with time. The kinetic metrics followed a pseudo-first-order outline, with the TiO₂-500 sample possessing the greatest rate constants (0.0124 min⁻1 for MG and 0.0147 min⁻1 for RhB). The DPPH assay demonstrated the highest antioxidant activity of 47.12 µg/mL IC₅₀ value for the TiO₂ nanoparticles calcinated at 700 °C, while the ones calcinated at 1000 °C showed a reduction due to grain growth and phase transition.