Sunlight-mediated photocatalytic removal of phenanthrene from wastewater using carbon-doped zinc oxide (C-ZnO) nanoparticles

Abstract

In an effort for efficient solar energy harvesting, carbon-doped zinc oxide (C-ZnO) nanoparticles with intriguing properties were synthesized by sonicated sol–gel technique with the aid of activated charcoal. Compared to pure ZnO, the incorporation of carbon has drastically promoted the photocatalytic activity of C-ZnO towards the degradation of phenanthrene under illumination of both UV and sunlight. The characterization of the as-synthesized nanoparticles by scanning electron microscope (SEM), UV–vis spectra, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS) confirmed the carbon doping of C-ZnO. The highest degradation rate of phenanthrene was obtained at pH 7 and C-ZnO loading of 0.5 g L−1. Finally, the kinetic studies of the photocatalytic degradation of phenanthrene by using C-ZnO were well-fitted with the Langmuir–Hinshelwood model and followed the pseudo-first-order rate expression.