Sol-gel Preparations of ZnO/SnO2 Composite Photocatalysts Applied for the Degradation of PAH’s under Visible Light

Abstract

Wastewater treatment challenges faced by conventional methods have necessitated the need for alternative/complementary methods that are environmentally benign and efficient especially toward recalcitrant organic pollutants. In this regard, ZnO/SnO2 composite photocatalysts were synthesized using sol-gel method and employed in the photocatalytic degradation of Phenanthrene, benzo(a)pyrene and naphthalene, typical PAH’s in water solution. The photocatalyst material was characterized with scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) to confirm the properties of the nanocomposite. The photocatalytic degradation activities of these nanocomposites towards phenanthrene, naphthalene and Benzo(a)pyrene were then investigated by measuring the effects irradiation time. In addition, the first-order kinetic model was used to determine the rate constant for the degradation reaction. The photocatalytic degradation data exhibited a trend fitting the pseudo first-order kinetics as defined by the Langmuir-Hinshelwood model, which allowed prediction of the faster degradation rate by the ZnO/SnO2 nanohybrid (NH). Keywords: Photocatalyst, Polycyclic aromatic hydrocarbons, composite