Heterogeneous activation of persulfate by NiFe2−xCoxO4-RGO for oxidative degradation of bisphenol A in water.

Graphical abstract Mechanism of the activation on PS by NiFe 0.7 Co 1.3 O 4 -RGO for the degradation of BPA. Highlights • Magnetic NiFe 0.7 Co 1.3 O 4 -RGO 1 was fabricated via a simple hydrothermal route. • Bisphenol A was completely removed by NiFe 0.7 Co 1.3 O 4 -RGO/PS in 25 min. • Co doping enhances the activity of the catalyst for persulfate activation. • BPA degradation is achieved partly via nonradical pathway promoted by RGO. • The influence of reaction parameters for the mineralization of BPA was evaluated. Abstract A simple route was reported for the synthesis of reduced graphene oxide (RGO) based NiFe 2−x Co x O 4 nanocomposite (NiFe 2−x Co x O 4 -RGO), a catalyst to activate persulfate (PS) for the degradation of bisphenol A (BPA). The crystalline structure and morphology of the composite were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). It is confirmed that spherical NiFe 2−x Co x O 4 nanoparticles with a size around 14 nm are uniformly anchored on RGO sheets. Compared with recently reported catalysts, NiFe 0.7 Co 1.3 O 4 -RGO 1 exhibits impressively higher catalytic activity, leading to much faster degradation of BPA with pretty less PS used. Moreover, the excellent catalytic performance can be maintained in a wide range of pH. The radical scavenging study and EPR experiments indicate that free radical, surface-bound radical and nonradical processes are involved in the degradation of BPA. In addition, the degradation of various organic contaminants other than BPA were also carried out, indicating that NiFe 0.7 Co 1.3 O 4 -RGO 1 /PS system has higher catalytic activity toward BPA. [ABSTRACT FROM AUTHOR]