3D-hierarchically structured Co3O4/graphene hydrogel for catalytic oxidation of Orange II solutions by activation of peroxymonosulfate

We report a 3D-hierarchically Co 3 O 4 /graphene hydrogel (CGH) composite as a catalyst activator of peroxymonosulfate (PMS) for sulfate radical-based degradation of Orange II in a heterogeneous system. The physicochemical performance of the composite is analyzed by X-ray diffraction spectra, scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results demonstrate that the samples are prepared resoundingly. The CGH hybrid composite completely removes Orange II wastewater within 6   min; furthermore, after five runs, the catalyst activity remains essentially unchanged and the macrostructure is followed consistently. This unusual macrostructure hydrogel of supported cobalt oxide indicates a high feasibility of commercial promotion to remove the azo dye.