Researchers at Texas A&M University have developed a non-toxic sequestering agent - iron oxide nano particles coated in a polymer mesh that can hold up to 10 times their weight in crude oil - a material that can safely soak up leftover oil, not captured using conventional mechanical means. As reported in the ACS Nano scientific journal, the nano particles consist of an iron oxide core surrounded by a shell of polymeric material - a simple poly(acrylic acid)-block-polystyrene that possesses both hydrophilic (poly(acrylic acid)) and hydrophobic (polystyrene) groups. This amphiphilic copolymer interacts with both the aliphatic hydrocarbons and aromatic components present in crude oil. Cross-linking the polymer makes the shell more stable in aqueous environments while maintaining the crude oil loading potential. To simulate an actual oil spill, the Texas A&M team weathered a sample of crude oil to match the conditions of the Deepwater Horizon spill. When the nano particles were dropped in the oil-water mixture, they immediately changed color from light tan to black as they soaked up the oil. When the nano particles were full they floated to the top, making for easy recovery by a conventional magnet, not only from a test vial but also in the ocean. A magnet was held to the side of the vial, nano particles collected at the glass, and the water was poured off, leaving the crude oil behind inside of the particles. Sonication in ethanol releases the oil from the swollen polymer matrix, causing the nano particles to return to a light tan. And although spectroscopic changes were observed after washing, the nano particles absorbed the same amount of oil during a second trial. In other words, the system is completely reusable. The next step will be creating an enhanced version that is biodegradable; as it stands, the existing particles could pose a threat if not collected once they’ve accomplished their duties. According to Karen Wooley, the principal investigator of the work, the project is still in the early stages. “But the fact that [our nano particle system] can capture 10 times its weight in crude oil is such a promising first result that I think they have significant potential," she said.