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

A simple route was reported for the synthesis of reduced graphene oxide (RGO) based NiFe(2-x)CoxO(4) nano-composite (NiFe(2-x)CoxO(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)CoxO(4) nano-particles with a size around 14 nm are uniformly anchored on RGO sheets. Compared with recently reported catalysts, NiFe0.7Co1.3O4-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 NiFe0.7Co1.3O4-RGO(1)/PS system has higher catalytic activity toward BPA.