Innovative Foam Filter Removes Microplastics with Ease

Researchers from Wuhan University have developed a self-assembled supramolecular biomass fibrous framework—a novel foam filter that can be revived and is highly effective at removing microplastics from complex aquatic environments. This breakthrough addresses the growing issue of plastic pollution, which has become a major global concern, especially due to microplastics that pollute waterways, soil, and accumulate in food webs and even human tissues. The challenge lies in the lack of conventional methods for removing microplastics, as well as the difficulty in handling the variety of particle sizes and chemistries.

Most current solutions to remove microplastics involve expensive or hard-to-recover materials, often underperforming in different environmental conditions or only targeting specific types of microplastics. Therefore, researchers have been focused on finding sustainable and affordable materials capable of adsorbing a wide range of microplastics.

In their study, published in Science Advances, the team introduced a new foam made from hydrogen bonding between protonated chitin nanofibers and cellulose fibers. The foam was tested across a variety of microplastics, including polystyrene, polymethyl methacrylate, polypropylene, and polyethylene terephthalate. The foam consistently performed well, even after multiple uses, with removal efficiencies ranging from 98.0% to 99.9%. After several cycles, the removal rate remained high, between 95.1% to 98.1%.

Performance tests showed that the foam has rapid adsorption kinetics, reaching equilibrium within just 24 hours. It proved effective across a wide range of microplastics, from small 100-nanometer polystyrene particles to 3-micron secondary microplastics. Computational analyses revealed that the foam's ability to capture microplastics involves a combination of physical interception, electrostatic attraction, and intermolecular interactions, such as hydrogen bonding and van der Waals forces.

The researchers highlight the foam's scalability, environmental adaptability, and recyclability in organic solvents. Its stability under different water conditions makes it a practical solution for large-scale microplastic removal. By using cost-effective and sustainable raw materials, this foam could provide an important tool for tackling the rising problem of microplastic pollution, offering significant advantages for microplastic remediation on a large scale.