Reusable Sponge Soaks up Oil from Water Column

When the Deepwater Horizon oil spill occurred seven years ago, beginning the worst oil spill in U.S. history, it was discovered that the millions of gallons of oil bubbling from the sea floor weren’t all collecting on the surface where they could be skimmed or burned. Some of the oil was forming a plume and drifting through the ocean under the surface.

Now, scientists at the U.S. Department of Energy’s Argonne National Laboratory have invented a new foam, called Oleo Sponge, that addresses the problem. The material easily adsorbs oil from water, is reusable and can pull dispersed oil from the entire water column, not just the surface.

“The Oleo Sponge offers a set of possibilities that, as far as we know, are unprecedented,” said 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.

“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.”

The scientists started out with common polyurethane foam, used in everything from furniture cushions to home insulation. They the 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, 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 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.

During tests at the National Oil Spill Response Research & Renewable Energy Test Facility, the Oleo Sponge successfully collected diesel and crude oil from both on and below the water surface.

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.

“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.

The team is actively looking to commercialize the material.