We’ve covered quite a bit of oil spill cleanup tech here, including these 10 ideas, these filters, these mini-submarines, these very light materials, and these oil-munching bacteria. They’re all potential alternatives to not-particularly-effective containment booms and the sort of toxic dispersants that BP used after the Deepwater Horizon disaster.
Oil spills are a difficult problem because of how oil behaves in oceans. Some of the liquid stays on the surface while some forms heavy droplets that sink downwards, either becoming suspended in the water or falling to the bottom. It’s very hard to get at these bits of the slick, short of using millions of gallons of chemicals.
Now a group of researchers from the Chinese Academy of Sciences may have a nature-inspired solution: droplet-collecting “skins” modeled after cactus plants.
The researchers noticed how cactus plants collect moisture from the air. Condensation covers the tips of their spines, which falls under its own weight to the base and gets absorbed by the plant. So they created their own “cactus skin”–artificial cone-shaped needles made of copper and coated in silicone. When submerged in water, the half-millimeter spikes draw down oil droplets and collect them at the bottom. The method is good for 99% of oil-water mixes and works with several types of oil, the researchers claim.
The work is published in the latest issue of the journal Nature Communications. The paper says:
Underwater, these structures mimic cacti and can capture micron-sized oil droplets and continuously transport them towards the base of the conical needles. Materials with this structure show obvious advantages in micron-sized oil collection with high continuity and high throughput.
The researchers think the device could also be used in the open air to remove fine droplets released with sprays. If so, we could see cactuses not only in the ocean and in the desert, but in city environments, too.