Magnetic CoFeO nanoparticles supported on graphene oxide (CoFeO/GO) with high catalytic activity for peroxymonosulfate activation and degradation of rhodamine B.

Herein, we report the preparation of magnetic CoFeO nanoparticles and CoFeO/graphene oxide (GO) hybrids and evaluate their catalytic activity as heterogeneous peroxymonosulfate (PMS) activators for the decomposition of rhodamine B. The surface morphologies and structures of both CoFeO nanoparticles and CoFeO/GO hybrids were investigated by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption-desorption isotherms. The magnetic properties of the samples were assessed using a SQUID magnetometer at 298 K. Catalytic oxidation experiments demonstrated that CoFeO/GO hybrids exhibited much better catalytic activity than CoFeO nanoparticles or CoFeO/reduced graphene oxide (rGO) hybrids, suggesting that GO plays an important role in CoFeO/GO hybrids in the decomposition of rhodamine B. The influence of various reaction conditions such as temperature, concentration of PMS, pH and decomposition time of rhodamine B over the CoFeO/GO catalyst were investigated and optimized. The rhodamine B degradation process was found to fit a pseudo-first order kinetics model. The catalyst could be easily separated from the reaction mixture by applying an external magnet. In particular, the as-prepared CoFeO/GO hybrid exhibited good reusability and stability in successive degradation experiments in PMS solution.