Laser-Enhanced Cork Emerges as Eco-Friendly Solution For Marine Oil Spills

Researchers from Central South University, Huazhong University of Science and Technology, and Ben-Gurion University of the Negev are using laser treatments to transform ordinary cork into an effective and nontoxic tool for cleaning up marine oil spills.

Cork is a highly renewable material as it can be harvested about every seven years from the bark of cork oak trees, which can live for hundreds of years. The teams’ choice to use cork as a clean-up solution actually came about accident:

“In a different laser experiment, we accidentally found that the wettability of the cork processed using a laser changed significantly, gaining superhydrophobic (water-repelling) and superoleophilic (oil-attracting) properties,” author Yuchun He said. “After appropriately adjusting the processing parameters, the surface of the cork became very dark, which made us realize that it might be an excellent material for photothermal conversion.”

“Combining these results with the eco-friendly, recyclable advantages of cork, we thought of using it for marine oil spill cleanup,” added author Kai Yin. “To our knowledge, no one else has tried using cork for cleaning up marine oil spills.”

The team has tested variations of a fast-pulsing laser treatment to achieve an optimal balance of characteristics in the cork at a reasonable cost. The photothermal properties that came about in the cork through this laser processing – along with the increased surface area –  allowed the cork to warm quickly in the sun. This energy is used to heat up spilled oil, lowering its viscosity and making it easier to collect. In experiments, the laser-treated cork collected oil out of water within 2 minutes.

“Oil recovery is a complex and systematic task, and participating in oil recovery throughout its entire life cycle is our goal,” Yuchun He said. “The next step is to prepare electrothermal materials using polyurethane foam as the skeleton for oil adsorption, combining photothermal and electrothermal techniques to form an all-weather oil recovery system.”