Because microplastics are so small — some as tiny as grains of sand — scientists have had a hard time figuring out to remove them from the soil and the sea.
Now, an Irish teenager has come up with a promising solution for this seemingly impossible task — a magnetic liquid that attracts microplastics to itself.
18-year-old Fionn Ferreira was kayaking one day when he spotted a rock covered in oil from a recent spill. Clinging to the oil were a bunch of tiny pieces of plastic.
“It got me thinking,” Ferreira told Business Insider. “In chemistry, like attracts like.”
Plastic and oil are nonpolar, making them likely to stick together in nature
Ferreira wondered if the effect could be recreated using ferrofluid, a magnetic, oil-based liquid invented by NASA in 1963 to keep rocket fuel moving in zero gravity.
Today ferrofluid is used to control vibrations in speakers and to seal off electronics to keep debris out.
Ferreira makes a more environmentally friendly version of the liquid than the kind used in rocket fuel, using recycled vegetable oil and magnetite powder, a mineral found naturally on Earth’s surface.
When he first drops the liquid into a container of water contaminated with microplastics, it disperses and turns the water black.
Then he dips a magnet in the water, which pulls out all the ferrofluid, plastic and all, leaving clear water behind.
The method removed 88% of the microplastics in his test samples.
The most difficult type of microplastic to remove was polypropylene, used to make all sorts of plastic packaging. Still, the ferrofluid removes 80% of polypropylene.
The easiest microplastics to remove were microfibers from plastic clothing such polyester, spandex and Lycra.
Washers and dryers are currently not equipped to filter these microfibers, which are a major source of ocean plastic pollution, so this is great news for that application.
Additionally, Ferreira‘s invention can be used at wastewater treatment plants as a sort of catch-all for microplastic pollution before it enters rivers, lakes and oceans.
Ferreira has won the Google Science award, $50,000 and educational funding for his invention.