A magnetic powder that can rapidly suck out all the microplastics in water could be used by water treatment plants to better remove the contaminants.
At present, most of these plants can remove only plastic fragments that are 5 millimetres in size or larger. That means smaller pieces end up in drinking water and oceans and are ingested by people and marine animals.
and at RMIT University in Melbourne, Australia, and their colleagues have developed a magnetic powder made from cheap components including iron oxide, trimesic acid and carbon produced from olive waste. The mix of components can absorb and trap microscopic plastic fragments within its structure, with the iron making it magnetic.
Advertisement
The researchers added 1000 milligrams of microplastics 鈥� each one-thousandth of a millimetre in size 鈥� per litre of water to create a microplastic soup. They then added 3000 milligrams of magnetic powder per litre to the soup and found that it absorbed 100 per cent of the plastics within an hour. The powder was sucked out using magnets, taking the microplastics with it. Afterwards, the researchers washed the magnetic material with alcohol to remove the microplastics, dried it and were able to reuse it six times.
鈥淭he beauty is, you just pour the powder into the contaminated water, mix it, give it an hour, then remove it with a magnet and you have clean water,鈥� says Eshtiaghi.
In contrast, other strategies that are being developed to take out microplastics, such as pumping water through fine filters, usually take longer and encounter problems like clogging, says Haris.
The team is now seeking industrial partners to test the method in a large-scale wastewater treatment plant. 鈥淲e hope it will be easy to implement and will make it easier to remove microplastics before they get into seawater,鈥� says Eshtiaghi.
Chemical Engineering Journal
Sign up to our free Fix the Planet newsletter to get a dose of climate optimism delivered straight to your inbox, every Thursday
