Fe3O4 hollow nanospheres on graphene oxide as an efficient heterogeneous photo-Fenton catalyst for advanced treatment of biotreated papermaking effluent

Abstract

This study focused on the feasibility of using Fe3O4/graphene oxide (FGO) nanocomposites as heterogeneous catalysts for the advanced treatment of real industrial wastewater. FGO nanocomposites with different graphene oxide (GO) ratios were synthesized by co-precipitating iron salts onto GO sheets in basic solution. Characterization of the resulting material structures and functionalities was performed using a range of analytical techniques. A low GO loading afforded a good Fe3O4 nanoparticle dispersibility and resulted in a higher Brunauer–Emmett–Teller surface area and pore volume. The FGO nanocomposites and pure Fe3O4 were used to treat papermaking wastewater in a heterogeneous photo-Fenton process. The results suggested that the nanocomposite designated FGO1 (GO loading of 25 mg) exhibits a higher photocatalytic efficiency than other FGO nanocomposites and pure Fe3O4. A maximum chemical oxygen demand degradation efficiency of 89.6% was achieved in 80 min with 1.5 g.L− 1 FGO1 at pH 3. The degradation of different pollutants present in wastewater was evaluated with the aid of gas chromatography–mass spectrometry and 3D excitation–emission-matrix analysis. Inductively coupled plasma atomic emission spectroscopy and magnetic measurements confirmed that the FGO1 nanocomposites possess a low iron leachability and a high reusability. Thus, a comprehensive advanced treatment of real industrial wastewater using a magnetic FGO catalyst is demonstrated.