Science Adviser, 4 December 2024

Bio-derived “sponge” soaks up microplastics

What do squid bones and cotton fibers have to do with one another? Perhaps the future of microplastics cleanup. Researchers report that they when they combine cotton with exfoliated sheets of chitin—the hard biomaterial that forms fingernails, insect exoskeletons, and, yes, squid ‘bones’ (their internal shells, also called quills)—the solid, porous foam formed attracts and immobilizes a wide array of microscopic bits of plastic.

Microplastics have become a ubiquitous scourge around the globe. They include bits of plastics 5 millimeters or smaller and come from everything from worn down chunks of plastic containers, paints, synthetic fabrics and tires. They’ve been detected in mountain snows, ocean sediments and just about everywhere in between. Researchers have also detected them in tissues throughout the human body, where they are thought to contribute to a wide array of health problems.

While researchers have come up with a variety of filters for capturing microplastics, few have proven efficient, reliable and cheap. In the new study, researchers found that their chitin/cotton foams could capture up to 99.9% of four of the most abundant types of microplastics from real-world water samples. And because the foams are made from two of the most abundant biopolymers on the planet, they could be cheap to make on a large scale and also degrade naturally when no longer useful.

Science Advances, 29 November 2024

Revivable self-assembled supramolecular biomass fibrous framework for efficient microplastic removal

Microplastic remediation in aquatic bodies is essential for the entire ecosystem, but is challenging to achieve with a universal and efficient strategy. Here, we developed a sustainable and environmentally adaptable adsorbent through supramolecular self-assembly of chitin and cellulose. This biomass fibrous framework (Ct-Cel) showcases an excellent adsorption performance for polystyrene, polymethyl methacrylate, polypropylene, and polyethylene terephthalate. The affinity for diverse microplastics is attributed to the transformation of multiple intermolecular interactions between different microplastics and Ct-Cel. Meanwhile, the strong resistance of Ct-Cel to multiple pollutants in water enables an enhanced adsorption when coexisting with microorganisms and Pb2+. Moreover, Ct-Cel can remove 98.0 to 99.9% of microplastics in four types of real water and maintains a high removal efficiency of up to 95.1 to 98.1% after five adsorption cycles. This work may open up prospects for functional biomass materials for cost-efficient remediation of microplastics in complex aquatic environments.