Scientists develop foam that can filter up to 99.9% of microplastics from water

(CN) — Scientists in China have developed a biodegradable foam that they say can remove up to 99.9% of microplastics from water, a major breakthrough in an effort to combat a pervasive environmental problem.

The contaminants known as “microplastics” — tiny pieces of plastic smaller than five millimeters in size that result from the breakdown of larger plastic materials or are made intentionally for use in cosmetic and biomedical products — have been found everywhere from the depths of the ocean to the most remote mountain ranges. Microplastics can persist in the environment for hundreds or even thousands of years and can also enter the food chain, harming wildlife and potentially human health.

“Microplastics entering terrestrial and aquatic habitats are anticipated to continuously increase for thousands of years, due to the alarming volumes of plastic waste in the environment,” the researchers write in a paper published Friday in the journal Science Advances.

“Currently, there are few practical technologies for efficient and extensive removal of microplastics, especially for those smaller than 10 (micrometers),” the paper’s authors add.

The scientists hope a new biopolymer they’ve developed could potentially help solve this problem. Made using cotton cellulose and chitin from squid bone, the material self-assembles into a fibrous foam dubbed Ct-Cel that has positively and negatively charged surfaces able to attract diverse microplastics.

In preliminary tests, the foam was able to absorb nanometer-scale particles of several plastics commonly used in industrial products. The scientists then tested the foam on samples from four real-world water sources to see how the material coped with water containing microorganisms and pollutants.

In the first test cycles, the foam was able to remove almost 100% of microplastics from samples of lake water, coastal water, agricultural irrigation water and still water. Over five cycles, the foam was able to absorb an average of between 95.1% and 98.1% of microplastics, showing its reusability.

Another benefit of this type of material is its recyclability, the researchers write, which not only reduces the cost of scaling up the process for use in the real world but also prevents microplastics from leaching back into the environment when the foam degrades.

“Our work provides a scalable design strategy for building functional biomass materials and broadening their application for microplastic removal in real water,” the researchers write, adding, “The Ct-Cel foam has great potential to be used in the extraction of microplastic from complex water bodies.”