A research team at Northwestern University in Evanston, Illinois, has invented a highly porous smart sponge that can successfully differentiate water from oil and soaks the latter liquid in the process.
According to the team, the sponge can absorb more than 30 times its weight in oil. It is touted as an inexpensive solution to clean up oil spills in the ocean without harming marine life. Like ordinary sponges, the smart sponge can be reused many times after the oil is squeezed out of it, and its effectiveness won't be affected, the team added.
According to Vinayak Dravid, the team's lead researcher, oil spills are not always big enough to make it to the news, but they are still harmful and invasive to the ocean's ecosystem, as well as in the communities around it. "Our sponge can remediate these spills in a more economic, efficient, and eco-friendly manner than any of the current state-of-the-art solutions," he said.
An oil spill is a massive environmental problem and requires an expensive and complicated process of clean up. Unfortunately, the clean-up process often harms marine wildlife despite the noble intentions of advocates.
To provide a solution to this global predicament, the Northwestern team used a nanocomposite coating of magnetic nanostructures, as well as a carbon-based substrate that is Oleohilic, Hydrophobic, and Magnetic (OHM) in nature. In layman's terms, the material they used to create the smart sponge attracts oils, resists water, and is magnetic.
The magnetic properties of the smart sponge are not similar to your ordinary magnet. It is designed so that only oil is attracted to it and does not absorb anything else, be it seawater or soil. But perhaps the OHM technology's greatest feature is the fact that it can be coated to any sponge available in the market.
The research team had already done it: they took a sponge, coated it with the nanocomposite slurry, squeezed out the excess, let it dry, and voila -- a perfectly working OHM sponge that's only attracted to oil.
Vinayak and his team of experts tested the smart OHM sponge with different types of crude oils of varying viscosity and density. The sponge was consistent in absorbing up to 30 times its weight in oil and always left the water behind.
Researchers had also emulated the movement of waves to make the test more true to nature. After being shaken, the OHM sponge only released less than 1% of the oil it absorbed back into the water.
You can read the entire paper in the journal Industrial Engineering and Chemical Research.
