When oil is on the surface of water it can be burned or skimmed-off to help minimize the impact. This established means of addressing oil spills is not always effective. A recent case was with the Deepwater Horizon drilling pipe burst. Here oil bubbled up from the seabed and not all of the oil collected on the surface, making standard methods ineffective. With the incident, on April 20, 2010 an uncontrollable blowout caused an explosion on the rig that killed eleven personnel and ignited a fireball causing the Horizon rig to sink. This left the oil well gushing at the seabed and triggering the largest oil spill ever in U.S. waters.
To ensure that a future ‘Deepwater’ event can be tackled, researchers from the U.S. Department of Energy’s Argonne National Laboratory have developed a new foam for soaking up oil. They’ve called this ‘Oleo Sponge’.
The basis of the foam is based on common polyurethane foam (the type that is contained within cushions); this material has good surface area. To make it suitable for grabbing oil it needed modifications to its surface chemistry so that it could attach to molecules of oil. This was achieved by growing an ultrathin layer of metal oxide “primer” near the foam’s interior surfaces. This functioned as a glue for attaching the oil-liking molecules, to hold onto the metal oxide layer and also to pull oil molecules towards the foam.
Speaking with Controlled Environments magazine, lead researcher Seth Darling explains: “The Oleo Sponge offers a set of possibilities that, as far as we know, are unprecedented.”
In tests the new material has been shown to easily adsorb oil from water. Here the foam can pull dispersed oil from the entire water column, not simply from the surface. A major trial took place in a giant seawater tank in New Jersey called Ohmsett. Both diesel and crude oil were successfully recovered both on and below the surface of the tank’s water.
A further advantage is with the sponge being reusable. It is also possible to extract and recover the oil from the material. The Oleo Sponge could also be used for standard cleaning operations, such as with harbors and ports. Here diesel and oil accumulate as a result of boat traffic.
The new material is undergoing commercial development and the research is described in the Journal of Materials Chemistry A, in a paper headed “Advanced oil sorbents using sequential infiltration synthesis.”
