Green Synthesis of Zinc Oxide Nanoparticles (ZnO NPs) Using Codiaeum variegatum Extract and Its Photocatalytic...

This study presents an eco-friendly approach for the synthesis of zinc oxide (ZnO) nanoparticles using the aqueous leaf extract of Codiaeum variegatum as a plant-derived capping and stabilizing medium. Zinc acetate dihydrate was reacted with the extract in an alkaline medium, followed by drying and calcination to obtain ZnO nanoparticles. The product was characterized by UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), thermogravimetric/differential thermal analysis (TGA/DTA), field-emission scanning electron microscopy (FESEM), energy-dispersive x-ray spectroscopy (EDX), and x-ray diffraction (XRD). The synthesized material exhibited the characteristic ZnO absorption near 380 nm and a hexagonal wurtzite structure, with an average crystallite size of 19.21 nm based on the Scherrer analysis. FESEM revealed predominantly spherical to slightly irregular particles with appreciable agglomeration. EDX detected Zn and O together with a sodium signal, with the analyzed region containing 65.12% Zn, 14.39% O, and 20.49% Na. The photocatalytic activity was evaluated using 50 mg L^-1 Basic Violet (BV) under natural sunlight. A degradation of 55.56% was obtained after 150 min in the presence of 0.50 g ZnO in 100 mL of dye solution. The apparent pseudo-first-order kinetic analysis gave k = 5.405 × 10-3 min^-1 with R² = 0.9639.