Removal of water-soluble lignin model pollutants with graphene oxide loaded ironic sulfide as an efficient adsorbent and heterogeneous Fenton catalyst

Advanced oxidation processes (AOPs) have gained extensive attentions in organic decontamination in past decades. Iron-contained compound is an interesting material due to its adsorptive and catalytic performance, which has been applied widely in AOPs. Thus, graphene oxide (GO)-Fe₃S₄ composite was synthesized by a solvothermal process and assessed as an effective adsorptive and catalytic dual functional material in this work. The composite displayed prominent adsorptive and heterogeneous Fenton-like catalytic performance, which was affected by preparation condition and the reactive parameters in catalytic system. Under optimized reactive conditions, the GO-Fe₃S₄ composite yielded rapid degradation of vanillic acid, which the corresponding apparent rate constant was 1.81 × 10⁻¹ min⁻¹. Catalytic mechanism analysis revealed that the main oxygen species was hydroxyl radicals bounded on the surface of the composite. And the generation of •O₂^– was contributed to the conversion of H₂O₂ to •OH. The analysis of degradation intermediates of vanillic acid and p-hydroxybenzoic showed that these compounds could be mineralized to small molecules. The prominent enhanced heterogeneous Fenton-like catalytic performance of GO-Fe₃S₄ was due to a larger specific surface area, plenty of reductive active sites in the composite and a high mass transfer efficiency of oxidizing radicals in the reactive system.