Preparation of Magnetically Recyclable Fluorinated Graphene and Its Demulsification Performance for Emulsified Oily Wastewater

Fluorinated graphene(FG) was firstly reduced by hydrazine hydrate to form the hydrophilic FG (HFG), and then magnetic Fe3O4 nanoparticles were further grafted onto the surface of HFG to synthesize HFG-Fe3O4 composite. The morphology, structure and chemical property of the samples were characterized by TEM, SEM, FTIR, XRD and XPS. In addition, the demulsification performance of HFG-Fe3O4 for oily wastewater was investigated and some affecting factors were discussed in detail. Moreover, the demulsification mechanism of HFG-Fe3O4 was proposed as well. The results show that the HFG-Fe3O4 is one kind of two. dimensional sheet-like material with Fe3O4 nanoparticles being uniformly distributed on its surface. The HFG-Fe3O4 has good demulsification performance on acidic and neutral oily wastewater, and its optimum dosage is 600 mg/L. Under the acidic and neutral conditions, the electrostatic attraction between HFG-Fe3O4 and the oily wastewater, as well as the pi-pi interaction between HFG-Fe3O4 and asphaltenes are the main forces pro. moting the oil separation from oily wastewater. However, the electrostatic repulsion between HFG-Fe3O4 and oily wastewater increases drastically under the alkaline condition, and ultimately results in the reduction of demulsification efficiency. What' s more, HFG-Fe3O4 still has excellent demulsification performance after 4 cycles, suggesting it has superior recyclability.