Potential applications of magnetic nanoparticles within separation in the petroleum industry

Magnetic nanoparticles have unique properties such as extremely large surface area per volume substance and strong magnetic response. In addition, the possibilities for surface functionalization make them exciting candidates for separation applications in oil and gas production and processing. Relevant separation applications discussed in this review are emulsion separation, oil spill clean-up, produced water purification, and mitigation of undesired phase separation. Surface coatings entailing polymers, surfactants, or inorganic compounds are typically used to protect and stabilize the nanoparticles and for further functionalization in targeting specific applications. The adsorption, or separation efficiency, of the functionalized nanoparticles in certain processes is found to reach as high as 99.99% and depends on the type of surface coating, proper nanoparticle dispersion in the target medium, and the chosen separation technique. Several magnetically driven methods available for nanoparticle recovery, or nanoparticle purification, are discussed with respect to their efficiency and possibilities for optimization. Safety concerns regarding the use of the nanoparticles in industrial work environments and potential risks of exposure are presented in the last section.