Green Synthesis of Semiconductor Nanocomposite (O-ZnO) Using Onion Peels Extract for Degradation of Organic Materials

The overuse of pharmaceuticals in recent years and the subsequent discharge of pharmaceutical waste, liquid waste, and harmful organic pollutants into the aquatic environment are important issues that should be seriously addressed. Therefore, this work presented an economical, environmentally sustainable, and simple method for producing zinc oxide nanocomposite using onion peel extract (OPE) and using this nanocomposite (O-ZnO) for organic pollutant removal as cefixime (Cfx) from aqueous solution using an advanced oxidation process. The synthesized materials in this study were characterized using analytical techniques, including (Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), field emission scanning electron microscopes (FESEM), and Fourier transform infrared spectroscopy (FTIR). The analysis showed that the surface area of onion peel extract (OPE), ZnONPs without OPE, and ZnO with OPE (O-ZnO) were 4.22, 30.1, and 49.3 m2/g, respectively. The findings indicated that the cefixime elimination efficiency of the O-ZnO nanocomposite attained 94%. Under the best operational conditions of pH 4, the dosage of O-ZnO (0.4 mg/L), Cfx concentration was (10 mg/L) with an optimum contact time of 120 min. The kinetic degradation rate of (Cfx) adhered to the pseudo-first-order equation with an R2 value of 0.9682, giving a constant degradation rate of 0.031/min.