A new foam, called Oleo Sponge, easily absorbs oil from water. And, it’s reusable. It can even pull dispersed oil from the entire water column—not just the surface.
The sponge could address clean-up challenges often encountered during oil spills, like those seen after the Deepwater Horizon spill, where oil forms a plume and drifts below the surface of the water.
“The Oleo Sponge offers a set of possibilities that, as far as we know, are unprecedented,” says co-inventor Seth Darling, a scientist with Argonne National Laboratory’s Center for Nanoscale Materials and a fellow of the University of Chicago’s Institute for Molecular Engineering. “We already have a library of molecules that can grab oil, but the problem is how to get them into a useful structure and bind them there permanently.”
How Oleo Sponge works
The scientists started out with common polyurethane foam, used in everything from furniture cushions to home insulation. This foam has lots of nooks and crannies, like an English muffin, which could provide 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.
Previously, Darling 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.
After some trial and error, they 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 absorbs 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.
Tested over and over in a giant seawater tank
Tests at a giant seawater tank in New Jersey called Ohmsett, the National Oil Spill Response Research and Renewable Energy Test Facility, the Oleo Sponge successfully collected diesel and crude oil from both below and on the water surface.
“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 says.
Oleo Sponge could potentially also be used routinely to clean harbours and ports, where diesel and oil tend to accumulate from ship traffic, says 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. They published preliminary results in the Journal of Materials Chemistry A.
“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 says.
The team is actively looking to commercialise the material, Harvey says. Those interested in licensing the technology or collaborating with the laboratory on further development may contact firstname.lastname@example.org.