Plastic pollution has hit crisis levels. It’s estimated that roughly 500,000 metric tons of plastic wind up in our oceans every year—a grim combination of land waste such as bottles, carpets, and food containers; and fishing industry equipment like buoys and nets.
The issue is that many of these plastics are incredibly durable, which means that they take a very long time to break down. This results in damage to ecosystems, harm to marine life, and even plastic making its way into our very bodies.
That’s why a team at Northwestern University created a solution that can break down one of the most pernicious and prevalent types of plastics—Nylon-6—in just a few minutes. The resulting byproduct is also clean, allowing it to be recycled and turned into durable plastic materials for later use. The team published a study of their findings on Nov. 30 in the journal Chem.
“This process doesn’t require toxic solvents, expensive materials, or extreme conditions, making it practical for everyday applications,” Liwei Ye, a polymer science researcher at Northwestern and the paper’s lead author, told The Daily Beast in an email.
When it comes to plastic pollution in the ocean, Nylon-6 is one of the biggest offenders. Some researchers estimate that fishing equipment containing the plastic make up more than 75 percent of the Great Pacific Garbage Patch alone. This is due to the fact that equipment like nets and ropes become unusable after just a few years of use—resulting in fishing companies abandoning them in the ocean rather than hauling them in to dispose of them.
When this happens, the nets along with the rest of the plastic debris in the ocean float through marine ecosystems where they wreak havoc on fish and wildlife species, while also leaching their plastics into the water where it eventually ends up in humans.
“There is a lot of garbage in the ocean,” Tobin Marks, a chemical engineer at Northwestern whose lab spearheaded the research and co-author of the paper, said in a statement. “Cardboard and food waste biodegrades. Metals sink to the bottom. Then we are left with the plastics.”
Unfortunately, there hasn’t been a great way to get rid of Nylon-6. When we burn it, it releases dangerous chemicals into the atmosphere. The other solution is to just bury it in landfills, but that can also be incredibly harmful to the environment.
That’s why Marks and his team decided to develop a catalyst that not only dissolves the polymers of Nylon-6, but does it quickly in a matter of just a few minutes. The solution breaks down the molecules of the plastic so it can then be reused to create new durable plastics.
“[The catalyst] acts on Nylon-6 when heated to melting temperatures, causing the plastic to revert to its original building blocks, or monomers, without generating any side products,” Ye explained. “This allows for the recovery of 99 percent of the original monomers, which can be upcycled into higher-value products.”
In fact, the recycled molecules are worth even more than just regular nylon, according to Ye. The team hopes to eventually scale up production of their catalyst to allow industries to break down Nylon-6 en masse. This would allow them to effectively recycle much of the plastic that ends up in the ocean, while also reducing the need to create new plastics, which is an incredibly resource-intensive process that requires a tremendous amount of oil to produce.
“Recycling the recovered monomers also reduces the need to produce new plastics from crude oil, which has a significant carbon footprint,” Ye said. He later added, “The goal is to use the catalyst on a large scale to address the global plastic problem.”