Chemists Develop Solvent-Free Catalyst for Nylon-6 Recycling
Nylon-6, a popular material among fashion purveyors, has long been a major hazard to the environment—the plastic in the fibers makes it too durable to degrade on its own.
And as global warming progresses and concerns over sustainability mount, brands and retailers have been looking to employ renewable or recycled nylon as a planet-friendlier alternative.
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Northwestern University chemists may have pioneered a solution that can give nylon-6 that elusive recyclable quality.
The scientists have developed a catalyst that completely breaks nylon-6 down in mere minutes. The process does not require a solvent, nor extreme conditions, which puts it in consideration for what a news release from the Chicago-area school calls “everyday applications.”
Scientists have previously looked into other catalysts that could degrade nylon-6, but those solutions require intense conditions or the addition of a toxic solvent.
“You can dissolve plastics in acid, but then you are left with dirty water,” Tobin Marks, the study’s senior author, noted in a release from the university. “What do you do with that? The goal is always to use a green solvent. And what type of solvent is greener than no solvent at all?”
When the catalyst, which harnesses silvery yttrium and lanthanide ions, interacts with nylon-6, it deconstructs the polymers and returns them to their original form as monomers. The researchers successfully recovered 99 percent of the polymer’s building blocks without leaving any harmful byproducts behind.
And the catalyst doesn’t disturb surrounding materials; it only interacts with nylon-6. Per the release, that means industries could “apply the catalyst to large volumes of unsorted waste and selectively target nylon-6.”
That helps eliminate the need for costly, tedious manual labor, Marks said in the release.
“If you don’t have a catalyst that’s selective, then how do you separate the nylon from the rest of waste?” Marks said. “You would need to hire humans to sort through all the waste to remove the nylon. That’s enormously expensive and inefficient. But if the catalyst only degrades the nylon and leaves everything else behind, that’s incredibly efficient.”
Once the catalyst has broken down the nylon, it can be reused to make new goods—a more environmentally friendly alternative to producing more nylon, especially given that nylon-6 is derived from fossil fuels. Currently, most nylon instead goes to landfills or is burned, emitting toxic pollutants.
Marks’ team knows that could be valuable in an industry hungry to keep up with looming climate regulations and consumer demand for sustainable goods.
“Recycled nylon is actually worth more money than regular nylon,” Marks said in the release. “Many high-end fashion brands use recycled nylon in clothes.”
Per the release, Marks and the research team have filed a patent for the breakthrough process. They have already received interest from industrial partners in using the catalyst.
Sourcing Journal reached out to Marks for comment.
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