Your laboratory is not well known in Europe. What can you tell us about it ?
The Argonne National Laboratory is part of the United States Department of Energy, it is one of the country's largest scientific and technical research centres. It is a multidisciplinary laboratory within which over 1,600 international researchers work towards meeting crucial challenges in the areas of energy, technology, the environment and security. Considerable collaborative work is conducted with experts from universities and other government laboratories. We are located in Lemont, Illinois, a suburb of Chicago.
The Oleo sponge received considerable media attention a few months ago. How did you come up with the idea for Oleo ?
We came up with the idea of working on this project in April 2010, after the Deepwater Horizon catastrophe in which an oil platform in the Gulf of Mexico exploded and released over 500 million litres of oil into the Atlantic Ocean. I don't know whether you remember this, but it took 87 days to plug the oil leak located at a depth of 1,500 metres. In the meantime, the oil spill spread across a surface area equivalent to the size of Virginia, contaminating the shores of five American states.
This catastrophe sent a shockwave through the United States. Scientists began to consider solutions for cleaning up the oil on the surface of the ocean and underwater. In fact, we believed that existing solutions such as combustion and skimming were insufficient because they were not cost-effective and entirely ineffective further than a few metres under the surface of the water. In addition, we thought it an interesting idea to recover the oil after having extracted it from the water, which had been impossible to date.
How did you go about designing Oleo ?
At the laboratory, we have a library of molecules able to capture oil. The hardest part involved devising a formulation or structure able to contain the oil molecules without releasing them. It is important to understand that our aim was to develop a type of sponge that would absorb only oil and would not release it at the slightest provocation. Polyurethane foam (the same used in acoustic panels) seemed to be the most promising material due to its honeycombed texture providing a sufficient surface for "catching" oil or any other oily liquid. However, the foam alone was not satisfactory as it tended to release the oil under the slightest pressure.
How did you improve it ?
It took many years of research to enrich the polyurethane foam with a material able to solidly capture the oil molecules like a magnet would with iron. In the end, we used a Sequential Infiltration Synthesis (SIS) system to inject metal oxide atoms into the sponge's nanostructures. This results in a thin layer that coats the internal surfaces of the foam and acts as a magnet to attract and retain the oil. Oleo was born! In the end, it is true that it resembles a mop more than a sponge, but it works perfectly on the surface of the ocean and at different depths. Oleo only absorbs oil and not water, and it just needs to be wrung vigorously to release the oil.
Have you been able to test it in a real life situation ?
Absolutely, just a year ago, after many tests in the laboratory, we decided to conduct a life-sized test at Ohmsett, a research institute in New Jersey which has a very large seawater basin. Oleo was able to recover the diesel and crude oil on the surface of the water and underwater. In addition, we found that the material is extremely robust. After hundreds of tests, and being wrung out as many times, it did not deteriorate. Our next aim is to conduct tests at very great depths, where there is considerable pressure.
What do you see in Oleo's future?
We hope that it will have a bright future! Oleo's effectiveness has been proven, and we are very proud of the result. In the end, few materials are able to absorb 90 times their weight and able to target the molecules to be captured. We believe that Oleo could be used to clean up ports where diesel and oils tend to accumulate. We have continued our research, however, because we believe that Oleo could absorb other molecules than oil or oily liquids by enriching it with something other than metal oxide.
We strongly believe that Oleo will be commercialised in the very near future. The only issues to be resolved relate to mass production, licenses, etc. That being said, our laboratory is currently at an advanced stage of discussions involving a dozen potential partners. We hope to see our sponge on the market within four to five years.