Activation of persulfate by heterogeneous catalyst ZnCo2O4 RGO for efficient degradation of bisphenol A

A nanocomposite, reduced graphene oxide (RGO) modified ZnCo2O4 (ZnCo2O4-RGO) was synthesized via one-step solvothermal method for activating persulfate (PS) to degrade bisphenol A (BPA). The morphology and structure of the nanocomposite were identified by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. RGO provides nucleation sites for ZnCo2O4 to grow and inhibits the agglomeration of the nanoparticles. The influence of different reaction conditions on the oxidation of BPA catalyzed by ZnCo2O4-RGO was investigated, including the content of RGO, the dosage of catalyst, the concentration of humic acid (HA), anions in the environment, the reaction temperature, and pH. BPA can be totally degraded within 20 min under optimized reaction conditions. The presence of HA, Cl-, and NO3- only has a slight effect on the oxidation of BPA, whereas the presence of either H2PO4- or HCO3- can greatly inhibit the reaction. ZnCo2O4-RGO shows good cycling stability and practical application potential. A reaction mechanism of the degradation of BPA was also explored.