🔄 This filter, inspired by sardines, captures 99% of microplastics from a washing machine

Nature may hold the key to cleaning the dirty water from our washing machines. Researchers have turned to fish, whose filtration systems have been perfected over millions of years, to design a simple device. Their goal is to capture the tiny plastic fibers that our clothes release with every wash, before they pollute rivers and soils.

These particles, called microplastics, represent a major environmental problem. Every year, a four-person household releases up to about 1.1 pounds (half a kilogram) of these fibers via its washing machine. Wastewater treatment plants do not remove them all, and many end up in fields via fertilizers. Finding a way to intercept them at the source, in the appliance itself, therefore appears to be a necessary path.

A Model Proven by Evolution

Some fish, such as sardines or anchovies, feed by filtering seawater. They swim with their mouths open and retain plankton thanks to an ingenious system located in their gills. This system works like a funnel whose walls are lined with fine teeth, forming a natural sieve. Water passes through this sieve and exits through the gills, while the food is captured.

The major advantage of this system is that it never clogs. Thanks to the funnel's sloped shape, plankton particles slide along the walls toward the fish's stomach, which swallows them. This permanent cleaning ensures effective and continuous filtration, an asset that conventional washing machine filters do not possess.

Scientists from the University of Bonn, whose work is published in npj Emerging Contaminants, have studied this mechanism carefully. They reproduced the funnel shape and the texture of the gill sieve using synthetic materials. By adjusting the fineness of the mesh and the angle of the slope, they adapted this natural model to specifically target microscopic plastic fibers.

An Effective and Simple Filter for Our Washing Machines

Laboratory tests of the prototype have yielded very promising results. The biomimetic filter captured over 99% of the microplastics present in the simulated wash water. This high performance is explained by the filter's very design, which guides the fibers along its surface rather than blocking them head-on, thus preventing rapid clogging.

The device is deliberately simple. It contains no complex or moving mechanical parts, which suggests a low manufacturing cost and high reliability. The captured fibers are collected at a single point, where they could be compacted into a small, solid pellet as wash cycles progress.

According to the researchers, maintenance would be minimal. The user would only need to remove this pellet of plastic waste every one or two months to dispose of it with household trash. This innovation, already being patented, paves the way for possible integration into future generations of washing machines, helping to significantly reduce this source of pollution.