Photocatalytic Degradation and Adsorption Kinetics of Microwave-Assisted Bio-Synthesized ZnO Nanoflakes for Removal of Toxic Organic Pollutants

Zinc oxide nanoflakes (ZnO NFs) have been synthesized using a rapid and eco-friendly microwave-assisted method (۴۰۰ W, ۱۸۰ s) with Litchi chinensis fruit extract as a green stabilizing agent. This approach enabled the precise formation of faceted nanostructures through accelerated nucleation and growth. The structural and compositional integrity of the ZnO NFs has been confirmed by X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), UV–visible spectroscopy, and field emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDX). Morphological analysis verified the plate-like ZnO nanostructures. The photocatalytic and adsorption properties of the NFs have been systematically investigated against organic dyes, including Safranin O, Bromophenol Blue, and Methyl Red. The nanoflakes exhibited remarkable photocatalytic efficiency, achieving ۹۷.۳۶% degradation of Safranin O under UV light (۱۲۵ W) within ۳۰ min, along with strong adsorption capacity. Kinetic and isotherm studies revealed that the adsorption followed a pseudo-first-order model, with the Freundlich model indicating a maximum adsorption capacity of ۵۴۱ mg/g. Furthermore, ZnO NFs demonstrated excellent recyclability over three cycles and retained high performance under varying pH and temperature conditions. These rapidly synthesized faceted nanoflakes present a promising material for photocatalytic and adsorption-based remediation of aqueous pollutants.

کلیدواژه ها:

Microwave irradiation ، ZnO ، photocatalytic activity ، Adsorption efficiency