Irish kid wins big for plan to get rid of microplastics using magnets.

Business Insider lauds Fionn Ferreira, an 18-year-old who won the Google Science Fair (and a $50,000 pot) with a plan to use ferrofluid – magnetic liquid – to stick to microplastics and pull them out of the ocean, rivers, even urban water plants:

One day while kayaking, he spotted a rock on the shore that was coated in oil from a recent spill. Attached to the rock were tiny bits of plastic less than 5 millimeters long — what scientists call “microplastics.”

“It got me thinking,” Ferreira said. “In chemistry, like attracts like.”

Plastic and oil are nonpolar, meaning they’re likely to stick to one another in nature. As a budding scientist, Ferreira had a hunch that the same effect could be created using a magnetic liquid found in speakers and electronic devices.

“I absolutely love ferrofluid,” said Ferreira, who makes his own version of the liquid by suspending magnetite powder — a mineral found naturally on Earth’s surface — in vegetable oil. (The leftover oil from fast-food chains like McDonald’s works well, he said.)

Ferreira said the most unique part of his mixture is that it can be used to remove plastic from wastewater — water discarded from homes, businesses, and industrial plants, for example. Studies have found that the world’s wastewater treatment plants aren’t equipped to filter out microplastics, even though they’re major contributors to microplastic pollution.

For his experiment, Ferreira injected ferrofluid into small glasses of water contaminated with microplastics. At first, the water turned black because of the magnetite, but when Ferreira placed a magnet inside the glass, it started to soak up all the fluid. Eventually, the water inside the glass was clear and mostly free of plastic.

Before embarking on his experiment, Ferreira wagered that his magnetic liquid could remove at least 85% of microplastics from his water samples. He wound up removing around 88%.

Of the 10 microplastics he tested, the most difficult fibers to remove came from polypropylene, a type of plastic used in product packaging, Ferreira said. But even then, Ferreira removed about 80% of polypropylene plastics, on average.

[via EcoWatch and Mr. McCann]