Researchers from Rice University developed magnetic nanoparticles to effectively isolate oil from water at wells.
Oil and water do not mix with each other. However, the mixture forms stable oil-in-water emulsions in produced water from oil reservoirs. Now, a research by Rice University published in the Royal Society of Chemistry journal Environmental Science: Water Research & Technology on August 15, 2018 reports development of a nanoparticle-based solution capable of removing over 99% of the emulsified oil in the produced water. The research was conducted by Sibani Lisa Biswal, an associate professor of chemical and biomolecular engineering and of materials science and nanoengineering— developed this magnetic particle at the Rice Lab.
Produced water from production wells contains oil along with other chemicals and surfactants. Although the water is pumped into a reservoir to push oil to the surface from tiny, some of the stable emulsions again formed clings back to the surface. According to the stats provided by Shell Global Solutions, the company that sponsored the research stated that 5% of oil remains emulsified at the surface that is hard to recover. Biswal found that injected chemicals and natural surfactants in crude oil are responsible for chemically stabilizing the oil-water interface. This leads to formation of small oil droplets that do not break easily.
Several prior experiments with magnetic particles and amines were conducted by former postdoctoral researcher and lead author Qing Wang. Based on these findings the researchers added amines to magnetic iron nanoparticles. The positive charge of amines aid the nanoparticles to find negatively charged oil droplets. The nanoparticles then bind the oil and magnets pull the droplets and the nanoparticles out of the solution. The team tested the novel nanoparticles on emulsions made in the lab with model oil as well as crude oil. The nanoparticles were inserted into the emulsions and mixed the solution simply by hand and machine to break the oil-water bonds and create oil-nanoparticle bonds. A magnet pulled the infused nanotubes to the bottom as some of the oil floated to the top, while placing the, leaving clear water in between.