An exciting development is taking place in the world of microplastic pollution as scientists are working on a new sound wave technology that can separate the particles in our washing machines.
A group of researchers led by Professors Hiroshi Moriwaki and Yoshitake Akiyama from Shinshu University in Japan have designed what’s known as a bulk acoustic wave (BAW) system.
The system has three separate channels. They begin with a central stream of microplastic-fiber-laden wastewater. It then moves on to a fork in the system. At the fork, a piezoelectric device is used and applies acoustic waves from the sides, and this creates a standing acoustic wave in the middle.
It is here, within the wave, that the fibers are caught and carried down the central channel. Clean microfiber-free water may then flow down the two side channels. The concentrated microfiber water could then be collected. The scientists’ thoughts on this are that most likely the water would need to be evaporated and the microfibers could then be collected.
In the laboratory setting where the BAW system was tested, they were able to capture 95% of the polyethylene terephthalate (PET) fibers and 99% of the nylon 6 fibers. These numbers are very promising, though more work will need to be done. They are now working on a technique to speed up the fiber-separation process, along with improving the draining of the water. As of right now, the machines tend to take a long time to drain.
The scientists pointed out that this method does not collect all the fibers; some sank due to gravity. Another recent advance uses magnetic microrobot swarms to trap microplastics with fish-schooling motion that actively sweeps water to improve capture rates. But both their theoretical estimates and their results lead them to believe that using acoustics to remove microplastics can be done.
It’s very promising to see scientists putting these things at the forefront of their research. We must find solutions to these problems. This discovery along with the filter scientists created a couple of years ago that helps break down microfibers give us some hope that we can help to clean our ocean waters, which would mean ingesting less plastic for wildlife and humans alike.
