Two New Materials May Help Halt Microplastic Pollution

By Mark Miller

The U.S. National Oceanic and Atmospheric Administration (NOAA) defines microplastics as pieces of plastic less than five millimeters in length. The agency’s web page adds that they are “the most prevalent type of marine debris found in our oceans and Great Lakes.”

Once microplastics get into the water, it can take hundreds or thousands of years for them to decompose. There is evidence, according to information from the University of Plymouth, that microplastics could harm birds and marine animals that may mistake them for food.

And microplastics aren’t only found in water. Based on reports from Science News Explores, they’re in the air, in soil, food, and even human blood. But two new materials may help slow their spread.

Preventative Potential

The article “Scientists Have Created Synthetic Sponges That Soak Up Microplastics,” published in Smithsonian Magazine, describes a new sponge that can absorb up to 90 percent of microplastics in seawater and tap water.

Researchers in China have developed a sponge so light it can be balanced on the petals of a flower. When a plastic-filled liquid is forced through it, it filters out microplastics and smaller nanoplastics. The sponges were created using mainly starch and gelatin, both biodegradable substances.

Potential applications vary from wastewater treatment to food production, but the key, explained chemist Anett Georgi from the Helmholtz Center for Environmental Research in Germany, is capturing microplastics before they enter the environment through water. Microplastics can find their way into water in different ways—when synthetic fabrics are washed, as microbeads that are part of health and beauty products, or simply from discarded pieces of plastic that degrade into smaller fragments.

Once in the water, they may be impossible to remove. “We have to stop it getting there in the first place,” she said in the article.

Algae-Based Meal for Microbes

What may be an even better way to reduce microplastic pollution is to engineer new plastics that break down more quickly than those commonly used today. That’s what Michael Burkart, a biologist at the University of California San Diego (UCSD), and his company, Algenesis Materials, are doing.

“To limit pollution, new recipe makes plastic a treat for microbes,” published in Science News Explores reports that Burkart and his team have developed a type of biodegradable polyurethane made from plants and algae. These plant-based building blocks, called esters, can be broken down and eaten by microbes.

The team compared how quickly the new material might break down by comparing it with ethyl vinyl acetate, or EVA, made from fossil fuels. First, they mixed the microplastics in a compost of plants, food waste, and microbes. When they checked the breakdown levels after 90 days, they found that 68 percent of the plant-based plastic had broken down. After seven months, according to the article, the level rose to 97 percent, while there was no sign of EVA breakdown in that time.

More Work for Less Microplastic

As research progresses, each of these technologies faces significant challenges and opportunities. For the sponges, demonstrating that they can be cost-effective in filtering microplastics on a large scale is key. The team at Algenesis Material is looking for ways to manufacture biodegradable, single-use plastics based on their algae-based polyurethane.