Functionalized graphene oxide with core-shell of Fe3O4@oliec acid nanospheres as a recyclable demulsifier for effective removal of emulsified oil from oily wastewater

Oily wastewater treatment has been proved to be one of the most crucial environmental concerns. In the present study, in the first step, hydrophobicity properties of Fe3O4 nanoparticles were modified by oleic acid (OA) to form Fe3O4@OA. Afterwards, graphene oxide (GO) nanosheets were functionalized with Fe3O4@OA nano-composite to synthesize novel superhydrophobic nanosheets of Fe3O4@OA/GO. Synthesized Fe3O4@OA/GO nanocomposite was employed as a fast, recyclable, high performance, cost-effective, and environmentally friendly nanodemulsifier to eliminate oil from oily wastewater. Demulsification performance of synthesized GO-based nanodemulsifiers was measured using bottle test as a function of dosage of nanodemulsifier, temperature, pH, and settle time. Mechanism of demulsification was investigated through optical microscopy. Finally, adsorption isotherms of asphaltene molecules and synthesized nanodemulsifiers were studied so as to achieve detailed and precise understanding regarding interaction between nanodemulsifiers and molecules of asphaltene. Demulsification tests revealed that Fe3O4@OA/GO nanodemulsifier with excellent demulsification performance (99.99%) had the ability to separate oil/water emulsion quickly, with demulsification capability for 6 recycle times.