New reusable sponge material soaks up oil from water
Staff
MaterialsOleo Sponge can absorb 90 times its weight in oil, which could have significant implications for future oil spill cleanup.
Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have invented a new foam that can easily absorb oil from water. This new material, called Oleo Sponge, not only absorbs oil from water, but goes beyond surface cleanup by absorbing dispersed oil from the entire water column.
Although there are already molecules available that can grab oil, one of the challenges for the scientists was how to arrange the molecules into a useful structure and bind them there permanently.
The scientists started out with common polyurethane foam. This foam has lots of nooks and crannies, which provides ample surface area to grab oil; but they needed to give the foam a new surface chemistry in order to firmly attach the oil-loving molecules.
Co-inventor Seth Darling, a scientist with Argonne’s Center for Nanoscale Materials and a fellow of the University of Chicago’s Institute for Molecular Engineering. and fellow Argonne chemist Jeff Elam had developed a technique called sequential infiltration synthesis, or SIS, which can be used to infuse hard metal oxide atoms within complicated nanostructures.
The team found a way to adapt the technique to grow an extremely thin layer of metal oxide “primer” near the foam’s interior surfaces. This serves as the perfect glue for attaching the oil-loving molecules, which are deposited in a second step; they hold onto the metal oxide layer with one end and reach out to grab oil molecules with the other.
The result is Oleo Sponge, a block of foam that easily adsorbs oil from the water. The material, which looks a bit like an outdoor seat cushion, can be wrung out to be reused—and the oil itself recovered.
“The Oleo Sponge offers a set of possibilities that, as far as we know, are unprecedented,” said Darling.
At tests at a giant seawater tank in New Jersey called Ohmsett, the National Oil Spill Response Research & Renewable Energy Test Facility, the Oleo Sponge successfully collected diesel and crude oil from both below and on the water surface.
Argonne postdoctoral researcher Ed Barry wrings out a sheet of Oleo Sponge during tests at Argonne. Photo by Mark Lopez/Argonne National Laboratory.
“The material is extremely sturdy. We’ve run dozens to hundreds of tests, wringing it out each time, and we have yet to see it break down at all,” Darling said.
Oleo Sponge could potentially also be used routinely to clean harbors and ports, where diesel and oil tend to accumulate from ship traffic, said John Harvey, a business development executive with Argonne’s Technology Development and Commercialization division.
Elam, Darling and the rest of the team are continuing to develop the technology.
“The technique offers enormous flexibility, and can be adapted to other types of cleanup besides oil in seawater. You could attach a different molecule to grab any specific substance you need,” Elam said.
Preliminary results were published in a study in the Journal of Materials Chemistry A, titled “Advanced oil sorbents using sequential infiltration synthesis.”
