Synthesis of magnetic nanoparticles (Fe۳O۴) coated with fatty acids and surfactants and their application in demulsification of crude oil-in-water emulsions

By the entry of crude oil into the water during exploration, extraction or displacement operations; due to the partial dissolution, it can remain as a layer on the surface of the water or become emulsive due to environmental forces such as tides or waves. Emulsion crude oil is very stable due to the presence of asphaltene and cannot be removed by the customary methods used for macro mode. In this research, iron oxide nanoparticles were coated with OA (oleic acid), SA (stearic acid), SDS (sodium dodecyl sulfate), CTAB (cetyltrimethylammonium bromide), PVP (polyvinylpyrrolidone) and POE (polyoxyethylene), by using the same method. After synthesizing iron oxide nanoparticles and coating their surface with fatty acids and surfactants, we have tried to break the crude oil emulsion in water and remove the crude oil from the environment by adsorption via these nanoparticles. Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), scanning electron microscope (SEM), TGA, VSM, EDS, X-ray diffraction (XRD) and Zeta potential devices were used to identify nanoparticles and their physical, chemical and morphological properties. Demulsification of crude oil in water (O/W) emulsion with nanoparticles coated with fatty acids and surfactants was studied. UV-Vis spectrophotometery was used to determine the amount of crude oil adsorption by nanoparticles. In the case of nanoparticles with a fatty acid coating, the smaller fatty acid chain shows absorption. The highest adsorption was recorded for iron oxide nanoparticles coated with polyoxyethylene (Fe۳O۴@POE) with ۹۸.۰۳% and the lowest percentage is related to nanoparticles coated with palmitic acid in an alkaline environment with ۴۶.۶۹%. Alkalinization of the medium while coating the nanoparticles with fatty acid has only increased the efficiency in the case of oleic acid and a significant decrease in the case of palmitic and stearic compared to the neutral state.

کلیدواژه ها:

Magnetic nanoparticles ، Emulsification ، Demulsification ، Water and crude oil emulsion ، Fatty acids