Microplastic-cleaning polymer foam

A foam made of the polymers cellulose and chitin removes up to 99.9% of microplastics from water and maintains its effectiveness after repeated use.

Microplastic pollution is increasing in terrestrial and aquatic environments at an alarming rate, making the need for practical approaches to remediate this urgent. The China-based research team set out to design a sustainable material that absorbs microplastics from water.

Plentiful polymers

The starting materials include two of the most abundant polysaccharides in nature: chitin, from the internal shell of squids, and cellulose from cotton. The team showed that these polysaccharides self-assemble into a foam with a highly porous, interconnected structure.

During initial testing, the researchers demonstrated the foam’s ability to adsorb tiny particles of the common plastics poly(phenylethene), poly(methyl 2-methylpropenoate, poly(propene) and poly(ethylene terephthalate).

Next, the team investigated how the foam performed with real-world water samples. It used irrigation, lake and coastal water – each containing a variety of plastics, toxic metals, chemical dyes and other pollutants. In the first cycle, the scientists found that the foam adsorbed microplastics from the water with 98%–99.9% efficiency, and after five cycles, it adsorbed microplastics with 95%–98% efficiency.