Synthesis and Characterization of Magnetic Nanoparticles and its Study to Displace Oil from a Hele-shaw Cell

Abstract

Abstract: Introduction: Oil spill incidents caused by human activities can cause major habitat damageand pose serious threats to all living organisms living on and within sources of water and soil.Finding a solution for oil spills is necessary to protect ecosystems, the environment, and health. Nanotechnologyseems to be an interesting tool in many applications, such as soil and water remediationand oil recovery. Nanoparticles are a good alternative since they are not as expensive as chemicalsused to remove oil.Objective: The prime purpose of this research work was the comparison of the additional displacementof sunflower oil from a single fracture using ferrofluids prepared with bare and novel covalentfunctionalized magnetic nanoparticles. Experiences were performed at constant nanoparticle concentrationand variable flow rate and at constant flow rate and variable nanoparticle concentration. Thenovel ferrofluid stability and its recovery properties related to a low-cost process were explored.Methods: Tests were carried out by image analysis. Stable ferrofluids were prepared using magneticnanoparticles (MNPs) and novel covalent functionalized magnetic nanoparticles (MSMs). Their abilityto displace the residual oil in a single fracture model previously invaded by an aqueous brine solutionwas tested. A flow channel of a single fracture by a typical transparent Hele-Shaw cell with 12% of itsarea covered by a random distribution of obstacles was modeled. Oil recovery was performed at threedifferent flow rates: 0.36, 1.80, and 3.60 mL min-1, using relatively low ferrofluid concentrations(0.0125 wt%). Oil recovery was also carried out with MSM ferrofluid at a constant flow rate of 1.80and 3.60 mL min-1 at different nanoparticle concentrations (0.00625, 0.0125, and 0.025 wt%).Results: Ferrofluids prepared with MSMs were more effective for oil recovery than those preparedwith bare nanoparticles due to their surfactant behavior for all flows studied here. A 7.86% extrapercentage of oil was removed after brine flooding. Oil recovery using MSM ferrofluid at a constantflow rate of 1.80 and 3.60 mL min-1 increased linearly with nanoparticle concentration. Magneticnanoparticles can be efficiently recovered and reused in at least three oil displacements for the fracturemodel used as covalent functionalization promotes ferrofluids´ stability.Conclusion: The characteristics of the MSM amphiphilic novel coating cause the nanoparticles to beattracted to both water and oil, enhancing oil displacement. These results indicate that this novelmaterial, whose structure stability is related to the covalent bonding of organic coating, can be consideredfor remediation and oil recovery in fractured media.