Vol. 6, Issue 2, Part A (2024)

A celery extract was used, and its pH was adjusted, to create iron oxide nanoparticles. Iron oxide nanoparticles were created when celery extract reduced iron (III) chloride (FeCl₃). These nanoparticles were then bio-functionalized to serve as stabilizing and capping agents. Iron oxide nanoparticles were generated by UV-visible spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The iron oxide nanoparticles' size, shape, and purity were all significantly impacted by the pH variations. The average crystallite size dropped from 23.23 nm (pH = 1.6) to 20.70 nm (pH = 12), according to the XRD results. The SEM photos show that as the particle size of α-Fe₂O₃ nanoparticles decreased from about 101.60 nm to 34.30 nm, the pH increased as well. Measurements in UV-vis indicate a narrowing of the bandgap from 5.62 and 3.33 eV. When it came to catalytic function, the nanoparticles outperformed the glutathione S-transferase (GST) enzymes in the pupae instar of Aedes aegypti mosquitoes, exhibiting a notably higher elimination activity with the highest efficacy. However, when calcined at higher temperatures, the CsPW catalyst was deactived to be less active than the other catalysts after 2-3 cycles. Furthermore, a possible antioxidant content related degradation mechanism of antioxidant was developed from two detected intermediates that is associated ln (Co/C) versus degradation period (h). In the meantime, the death rate of α-Fe₂O₃ nanoparticles at pH 1.6 was 70-75%, while it rose up to 90-99% at pH 12.