Most of the materials designed for removing oil spills from water are single-use, meaning that they’re bound to eventually end up in landfills. We’ve written about the potential to use shed dog fur for oil spill cleanups, and now, scientists have developed an oil-absorbing sponge that can be used multiple times and eventually biodegrade.

Created by a team from Singapore’s Nanyang Technological University (NTU) and South Korea’s Sungkyunkwan University, the novel material is made of plant pollen and it requires a similar production process to that of making soap.

For the process, the researchers collected pollen grains from sunflowers, which were already covered with a sticky oil-based substance. That substance was then separated from the grains by submerging the pollen in alkaline conditions for three days.

The remaining gel-like substance was then freeze-dried to form a porous material, which was subsequently heated to 392 ºF to stabilize it. The final step involved coating the material with a layer of stearic acid — a fatty acid found in vegetable and animal fat.

In addition to being porous, the resulting material has hydrophobic properties. This means that, if placed in oil-polluted water, the sponge would only soak up the oil and leave the water behind.

When tested, the new sponge exhibited similar absorption qualities to commercially available plastic-based absorbents. However, in contrast to its petroleum-based counterparts, the sponge is entirely made of renewable materials that biodegrade once discarded — which would only happen after it has been reused.

“By fine-tuning the material properties of pollen, our team successfully developed a sponge that can selectively target oil in contaminated water sources and absorb it,” said study lead author, Prof. Cho Nam-Joon. “Using a material that is found abundantly in nature also makes the sponge affordable, biodegradable, and eco-friendly.”