Synthesis of Cerium-Doped Zinc Oxide Nanocomposites and Their Application for Photocatalytic Degradation of Lambda-Cyhalothrin in Agricultural Runoff Under Natural Solar Irradiation

Abstract

Heterogenous photocatalysis is one of the promising methods of degradation of organic pollutants in the environment. This study developed a suitable and efficient method for photocatalytic degradation of Lambda-cyhalothrin LCY pesticide using Ce–ZnO nanocomposites under natural solar irradiation. Ce–ZnO was synthesized using the coprecipitation method and was ascertained through structural characterization. The crystal structure and crystallite size, surface morphology, functional groups present, and the elemental composition of the synthesized nanocomposites were determined by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDAX), respectively. The average crystallite size of the nanocomposites was found to be 31.42 nm. The photocatalytic degradation of LCY was conducted in batches to obtain and determine the optimal conditions for the degradation of the pesticide. It was found that at optimum conditions; 100 ppm LCY initial concentration, 20 mg dose of the photocatalyst, and 10–11 UV index, Ce–ZnO were found to degrade about 92% of the initial concentration of LCY after 3 h of exposure to solar irradiation. It was found that Ce–ZnO possesses high photocatalytic activity against LCY and the kinetic of the degradation was found to fit the pseudo-first-order kinetic model.