Optimization and characterization of magnetitereduced graphene oxide nanocomposites for demulsification of crude oil in water emulsion

Oily wastewater from the oil and gas industry negatively affects the environment. Oily wastewater typically exists in the form of an oil-in-water emulsion. Conventional methods to treat oily wastewater have low separation efficiency and long separation time and use large equipment. Therefore, a simple but effective method must be developed to separate oil-in-water emulsions with high separation efficiency and short separation times. Magnetitereduced graphene oxide (MRGO) nanocomposites were used as a demulsifier in this work. Magnetite nanoparticles (Fe 3 O 4 ) were coated on reduced graphene oxide (rGO) nanosheets via an in situ chemical synthesis method. The synthesized MRGO nanocomposites are environmentally friendly and can be recovered after demulsification by an external magnetic field. MRGO characterization was performed using X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, field emission scanning microscopy, Raman spectroscopy, and vibrating sample magnetometry. Demulsification performance was evaluated in terms of MRGO dosage, effects of pH, and brine concentration. The demulsification capability of MRGO was determined based on the residual oil content of the emulsion, which was measured with a UV-vis spectrometer. The response surface method was used to determine the optimum conditions of the input variables. The optimum demulsification efficiency achieved at pH 4 and MRGO dosage of 29 g L 1 was approximately 96%. This finding demonstrates that MRGO nanocomposites are potential magnetic demulsifiers for oily wastewater that contains oil-in-water emulsions. Also, the recyclability of this nanocomposite has been tested and the results shown that it is a good recyclable demulsifier. Magnetite reduced graphene oxide were synthesized for separation of crude oil in water emulsion.