Green Synthesis of Metal Oxide Nanoparticles and evaluation as Photocatalytic Degradation of Imidacloprid Pesticide

Copper oxide and nickel oxide photocatalysts were synthesized using Abelmoschus esculentus leaf extract and their photocatalytic properties were evaluated by degrading recalcitrant pesticide imidacloprid. A rapid, economical, and environment friendly biosynthesis produced high-surface-area CuO and NiO photocatalyst nanoparticles. The CuO and NiO nanoparticles were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermo-gravimetric/differential thermal analysis. The XRD studies showed that the synthesized nanoparticles have a face-centered cubic structure. Photocatalytic degradation study showed nanoparticles bear good potential to degrad Imidacloprid. The degradation was found to be affected by the Imidacloprid concentration, solution pH, and photocatalyst dosages. The pesticide degradation percentage (~99%) was attained by CuO photocatalyst that was higher than for NiO photocatalyst (~81%). The degradation follows pseudo-first-order kinetic model, and the apparent rate constant (Kapp) decreased from 0.028/min for CuO to 0.0076/min for NiO photocatalyst. The nanoparticles demonstrated high water stability and recyclability.