Water chemical treatment by photocatalytic activity of reduced graphene oxide-decorated zinc sulfide nanocomposite

Abstract

The photocatalytic properties of reduced graphene oxide decorated ZnS nanocomposite was employed for photodegradation of phenol red as a chemical agent in water. ZnS nanocomposite was synthesized by hydrothermal method. Reduced graphene oxide decorated ZnS nanocomposite was produced by pulsed laser ablation of graphite bulk in the solution of ZnS nanocomposite. Variety of spectroscopic and imaging diagnostics including X-ray diffraction (XRD), UV-Vis absorption spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were used to characterize the synthesized nanostructures. Water treatment was carried out in a closed handmade reactor. The concentration of the phenol red pollutant as the chemical agent, was extracted from the absorption spectra of treated water. Dependence of the behaviors of phenol red dye on the pH of the medium was studied in detail. Effects of UV radiation intensity, treatment time, pH of the polluted water, and aging on the efficiency of the treatment were investigated. Results show that even in the dark condition rGO-ZnS nanocomposite is an effective material to remove phenol red pollutant from water. The highest efficiency of treatment after 120 minutes was achieved in neutral pH water. Furthermore, after 7 days, with nanostructures and without UV radiation, the removal process in the polluted water was continued.