Most of the materials used for cleaning up oil spills are used only once, after which they are bound to end up in landfills. Now, however, scientists have created an oil-absorbing sponge that can be used over and over again.
Developed by a team led by Illinois-based Northwestern University, the actual sponge itself is much like any other. What makes it special, however, is the thin coating that’s applied to it, made up of magnetic nanostructures, on a carbon-based substrate.
That substrate is both oleophilic and hydrophobic, meaning (respectively) that it attracts oil and repels water. As a result, the sponge can soak up over 30 times its weight in oil, without also filling up on water. That oil can subsequently be squeezed out for safe disposal or reuse, leaving the sponge ready to take up more.
Additionally, the magnetic aspect of the coating allows it to be moved around the water’s surface with the help of a large ship-mounted electromagnet, similar to those seen at auto wrecking yards.
What’s more, when an external radio is applied to the sponge, it’s absorbed by the magnetic nanostructures, causing them to heat up to around 60 ºC (140 ºF), allowing the sponge to release its oil payload, when squeezing alone isn’t enough.
Down the road, the technology could conceivably be adapted to selectively soak up and release other waterborne pollutants, such as dissolved nutrients from agricultural runoff or sewage.