Magnetically recoverable Fe3O4-modified bentonite as a heterogeneous catalyst of H2O2 activation for efficient degradation of methyl orange

Clay-based materials provide an efficient and environmentally benign strategy for heterogeneous catalytic oxidation. In this study, a novel Fe3O4-modified bentonite (Fe3O4-BT) catalyst was obtained by using the hydrothermal method. The catalyst was characterized by transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The Fe3O4 nanoparticles mainly existed on the surface and in the outermost pores of the BT, thus exhibiting improved dispersion and lower levels of aggregation. The catalytic activity of Fe3O4-BT was assessed in the degradation of methyl orange (MO) in the presence of H2O2. Fe3O4-BT showed higher MO degradation efficiency than both bare Fe3O4 and BT. The initial H2O2 concentration, catalyst loading, temperature, and initial pH were optimized for the degradation of MO. The MO decolorization rate was still similar to 90% after the Fe3O4-BT was reused five times. Additionally, the degree of ferric ion dissolution was only 3.23 x 10(-3) mg/L after 60 min. This novel catalyst was easily reclaimed by simple magnetic separation and exhibited good reusability and stability.