Synthesis and application of ZnO/rGo-based magnetic nanocomposite materials for treatment of organic pigments

Abstract

Photocatalysis is one of the most effective techniques for treating organic pigments in wastewater. Some composite materials are prepared by combining photocatalysts and magnetic adsorbents and are used for treating organic pigments in water. In this work, zinc oxide-doped rGO-based nanocomposite materials were prepared via a simple process. In particular, Fe2O3 was added to those nanocomposites to form magnetic photocatalytic materials that can be recovered and reused after reactions. The material structure was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and ultraviolet–visible diffuse reflectance spectroscopy (UV‒Vis DRS). Rhodamine B (RhB) and methylene blue (MB) were photochemically treated with the prepared magnetic photocatalytic materials. Ultraviolet–visible spectroscopy (UV‒Vis) was used to determine the concentrations of organic pigments before and after treatment with the materials. The photocatalytic degradation efficiency of MB and RhB reached more than 84% after 75 min and more than 98% after 6 h, respectively. The magnetic photocatalytic materials effectively recovered (up to 92%) after 3 cycles. In addition, the mechanism of photocatalytic degradation was investigated via capture experiments. The results indicated that magnetic photocatalytic materials can effectively treat MB and RhB in water and can be recovered and reused, showing their potential as attractive alternatives to treating organic pigments in wastewater.