LAUSR

Abstract Here in, a system of Co3O4/CoO catalyst activated with the aid of bisulfite (NaHSO3) was established for the decomposition of methylene blue (MB). The Co3O4/CoO material was designed by a two-step uniform precipitation and calcination method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) spectroscopy to detect the crystallinity, morphology, magnetic ability, element valence and the different types of free radicals, respectively. The efficient degradation of MB relies on the synergistic effect between the Co3O4/CoO catalyst and bisulfite (NaHSO3) to generate some strongly oxidizing radicals, which could achieve a MB degradation rate of 90.7% within 40 min using this novel system. Additionally, the ferromagnetic property of Co3O4/CoO catalyst is expected to supply an excellent magnetic separation ability to help separate the solid catalyst from the aqueous solution. The novel catalyst system of Co3O4/CoO/NaHSO3 may serve as a promising new system for wastewater treatment.