Tiny plastic particles are turning up almost everywhere, including in drinking water.
Now, researchers in South Korea have developed a new filtration technology that can remove more than 99% of the smallest and most dangerous plastic fragments—without needing an external power source.
The breakthrough comes from Professor Jeong-Min Baik’s research team at Sungkyunkwan University’s School of Advanced Materials Science and Engineering.
Their newly designed filtration platform targets nanoplastics smaller than 50 nanometers, which are so small that tens of thousands could fit across the width of a human hair.
These particles are especially concerning because they can slip through the body’s natural barriers, enter cells, and potentially disrupt immune systems or increase the risk of disease.
Conventional water filters struggle to capture plastics at this scale. As a result, nanoplastics have been detected even in bottled water, sometimes in alarmingly high numbers.
This has highlighted the urgent need for new purification methods that can deal with ultrafine plastic pollution.
To solve this problem, Professor Baik’s team developed a reusable filter that uses electricity to pull nanoplastics out of water.
The filter is made from a porous metal and coated with magnesium oxide and a specially designed polymer. When an electric field is applied, the filter surface becomes positively charged, allowing it to strongly attract negatively charged nanoplastic particles as water flows through.
Even under high-flow conditions similar to those used in commercial water treatment systems, the filter removed more than 99% of nanoplastics measuring 50 nanometers or smaller.
The results were reported in the journal Materials Today.
One of the most innovative features of the system is that it can operate without a battery or external power supply.
The researchers paired the filter with a triboelectric generator, a device that produces electricity from mechanical motion, such as flowing water or movement. This makes the filtration platform fully self-powered and suitable for off-grid or remote locations.
The filter is also designed to be reusable. By reversing the direction of the electric field, the captured plastic particles are released from the filter surface, allowing it to be cleaned and used again. Tests showed that the system maintained its performance even after being reused more than 20 times, making it both cost-effective and environmentally friendly.
Importantly, the technology worked reliably in real-world water sources, including tap water and river water. The purified water met World Health Organization drinking-water standards, demonstrating the system’s practical potential.
Professor Baik said the study not only introduces a powerful new filtration method but also provides a clear mathematical explanation of how electrokinetic forces can be used to capture nanoplastics underwater. Looking ahead, the team believes the technology could be adapted for removing bacteria or selectively recovering valuable metal particles from water.
The researchers have already filed a domestic patent and are now working to bring the technology closer to real-world use, offering hope for cleaner and safer drinking water in the future.
