PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

ZrO2 nanoparticles were synthesized using an environmentally friendly process. The synthesis involved zirconium oxynitrate, NaOH, and deionized water to produce zirconium oxide (ZrO2) nanoparticles. Initially, Zirconium oxychloride octahydrate was dissolved in distilled water and stirred for a duration of 30 minutes. Subsequently, the Amaranthus campestris plant extract was incorporated into the zirconium oxynitrate solution and stirred at a temperature range of 40-45°C, followed by the addition of a small quantity of NaOH to the mixture. The resulting solution underwent centrifugation five times, and the resultant powder was subjected to annealing at 500°C for two hours. The synthesised ZrO₂ nanoparticles were characterised using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FESEM), and photocatalytic analyses. XRD results confirmed the formation of tetragonal-phase ZrO₂ nanoparticles with an average crystallite size of approximately 15 nm. FESEM observations indicated the formation of crystallites accompanied by agglomeration. UV-Visible optical studies demonstrated a sharp transition, with the corresponding bandgap measured at 5.5 eV. The antioxidant properties of the green-synthesized ZrO2 nanoparticles were assessed using the DPPH assay method, with ascorbic acid serving as a control. The synthesised zirconium oxide (ZrO₂) nanoparticles demonstrated considerable antioxidant activity when compared with the reference standard, ascorbic acid. To evaluate their photocatalytic performance, ZrO₂ nanoparticles at a concentration of 1 g/L were dispersed in 50 mL of methylene blue (MB) dye solution and maintained in a photoreactor under visible light irradiation to examine dye degradation. The experimental findings confirmed that the nanoparticles effectively facilitated the degradation of MB dye under visible light exposure. Following 120 minutes of irradiation, the photocatalytic degradation efficiency was determined to be 78%.