NU research group discovers way to dispose of forever chemicals

2022-10-15 08:14:13 By : Ms. Wendy She

Daily file photo by Ava Mandoli

Technological Institute. The new study is a breakthrough in the fight to properly dispose of forever chemicals.

Davis Giangiulio, Assistant Campus Editor October 12, 2022

A Northwestern research group has discovered a new way to properly dispose of “forever chemicals.”

Forever chemicals, known as PFAS, are human-made chemicals that are categorized as surfactants — compounds that decrease surface tension. They are used in manufacturing disposable items like food packaging products and Teflon. However, these chemicals don’t break down naturally and there is no universally recognized solution to properly dispose of them.

That’s where the NU research group, led by chemistry Prof. William Dichtel, comes in. The group discovered a certain procedure that can break down the chemicals. The process involves heating PFAS in a dimethyl sulfoxide and sodium hydroxide mixture that breaks the PFAS chemical bonds.

Dichtel said the researchers originated the idea from recent research suggesting a way to dispose of PFAS, which the NU group successfully pursued.

“(The papers) suggested that some of these forever chemicals might have this kind of Achilles heel, or this weak point that would allow them to be degraded under more mild conditions,” Dichtel said. “That really proved to be true.”

Brittany Trang (TGS ’22), a former member of the research group and lead author of the study published in the journal Science, discovered the solution. 

Trang said the discovery is significant because cities currently consume excess energy when trying to destroy PFAS.

“Incineration is the only one that’s used in a municipal fashion, and there’s proof that that is actually not destroying PFAS and instead just spreading them around the community,” Trang said. “These high-energy things are not targeted to PFAS specifically, but the idea is if you put a lot of energy into the system, eventually we will end up breaking things.”

The group’s solution, on the other hand, is relatively simple and necessitates a less energy-intensive environment, Trang said.

She added that the remedy went unknown for a long time because ideas for destroying PFAS were often viewed from an engineering perspective, relying on infrastructure that already exists for dealing with the chemicals.

“People hadn’t approached this from a chemistry standpoint before,” Trang said. “This more unique way of doing it allowed us a lot of insight into what might work.”

Mohamed Ateia, a former research associate with Dichtel’s group who has an environmental engineering background, said he believed the blend of engineering and chemistry perspectives allowed for the breakthrough.

The discovery, Ateia added, is extremely significant for materials chemistry.

“What we opened here is a new door that no one even knocked before,” Ateia said. “This whole field of chemistry is very young, we’re talking about decades compared to chemistry age. So we are still learning.”

While the discovery is consequential, group members also acknowledged its limitations.

The most important caveat is that the process only applies to PFAS with carboxylic acids, which make up only about 40% of all forever chemicals, Trang said. The group doesn’t know yet if it applies to sulfonic acid PFAS and other types of forever chemicals. 

Trang also said the impact of the research won’t be applicable for a while, as municipality treatment plants won’t be able to implement the procedure overnight. However, Trang and Dichtel think the more immediate consequence of the finding will be the further investigation it inspires.

“Recognizing these mechanisms … will hopefully inspire us and others to go try to find ways to get some of those other forever chemicals to enter these degradation pathways,” Dichtel said.

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