Sepiolite/Fe3O4 composite for effective degradation of diuron

A novel sepiolite-supported Fe3O4 magnetite (SepMag) composite was prepared for diuron degradation. The samples were characterized by X-ray powder diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), N-2 adsorption-desorption and BET surface area analysis, scanning electron microscope (SEM) as well as transmission electron microscope (TEM). The chemical state of Fe in SepMag composite before and after degradation experiments was characterized by X-ray photoelectron spectroscopy (XPS). The enhanced degradation efficiency for diuron was attributed to the effective generation of hydroxyl radical in ultrasound/SepMag/H2O2 system. The degradation rate of diuron depended upon the composite amount, hydrogen peroxide dosage, initial pH of solution and temperature. The degradation reaction was also optimized by changing the ultrasound intensity and Fe3O4 content in the composites. Moreover, mineralization and degradation pathway were evaluated on the basis of total organic carbon and liquid chromatography mass spectrometry. It was confirmed that with the assistance of ultrasound treatment SepMag composite has potential advantages for the removal of diuron from aqueous solution.