Highly Efficient Photodegradation of RHB-MO-MB Mixture Dye Wastewater by WO3/Fe3O4/Diatomite under Different Condition

Abstract

In this study, the composite photocatalyst WO3/Fe3O4/Diatomite was developed by solvent thermal method to remove composite dyes from wastewater. The structure and properties of the photocatalyst were characterized and analyzed. Under the effect of Fe3O4, WO3 was found to be enhanced in the direction of (101) and (200) and loaded on the surface of diatomite (DT). The results of UV–vis analysis imply that the Fe3O4 and diatomite can significantly improve the photocatalytic efficiency. The magnetic hysteresis loop shows that the WO3/Fe3O4/DT composites can be recycled by a magnet, indicating the good recyclability of the composite photocatalyst. The WO3/Fe3O4/DT composite showed a good photocatalytic effect in both acidic and alkaline conditions for RHB-MO-MB mixture dye, which exhibits broad application prospects. The results of the free radical analysis indicate that ·O2 − and ·OH were the main active species. The mechanism of photocatalytic removal of dyes was investigated based on radical trapping experiments and energy band structure analysis. It was proved by three photocatalytic cycle experiments that the morphology of the WO3/Fe3O4/DT composites remains unchanged, and the photocatalytic activity is maintained during recycled operations. This work provides a new idea for dye removal from wastewater using photocatalysts.