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 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.