Magnetic nanostructured MnFe2O4 with different morphologies, synthesized via chemical co-precipitation and hydrothermal method, was assayed as heterogeneous Fenton catalysts. The as-prepared MnFe2O4 catalysts were thoroughly characterized by various characterization methods, such as X-ray diffraction (XRD), N2 adsorption-desorption, transmission electron microscopy (TEM), magnetic hysteresis loops, temperature-programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). The catalytic activity of MnFe2O4 catalysts was evaluated in the heterogeneous Fenton degradation of ofloxacin (OFX). In our study, the morphology exhibited a critical impact on the catalytic activity of MnFe2O4. For example, MnFe2O4 nanorods (MnFe2O4-NR) had a higher catalytic activity than MnFe2O4 nanospheres (MnFe2O4-NS) and MnFe2O4 nanocubes (MnFe2O4-NC) in OFX removal and H2O2 decomposition. Notably, the catalytic activity was remarkably enhanced with increasing the relative amount of Mn3+ and Fe2+ species on the surface. Based on the results from quenching experiments and quantitative determination of •OH radicals, a possible catalytic mechanism of MnFe2O4 was proposed. In addition, the stability and reusability of MnFe2O4-NR was ascertained, as the results suggested that MnFe2O4-NR was a stable and easily separated catalyst for heterogeneous Fenton process.
Keywords: Heterogeneous Fenton reaction; Magnetic catalyst; MnFe2O4; Morphology; Ofloxacin.