Light-based photocatalytic system can break down PFAS at room temperature

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Researchers at Colorado State University have found a new approach for breaking down PFAS—a group of human-made "forever" chemicals commonly used for their water-resistant properties that can carry health risks from long-term exposure.

The carbon-fluorine bond found in PFAS (perfluoroalkyl and polyfluoroalkyl substances) compounds is particularly challenging to break apart. That durability has led to widespread use of these manufactured chemicals in medical, industrial and commercial settings.

However, that inherent stability has also made them difficult to dispose of, and over time, they have made their way into water, air and soil across the world, according to the Environmental Protection Agency. The EPA says exposure to these lingering compounds can lead to health problems, including cancer or reproductive issues.

In a paper published in Nature, CSU researchers showcase an effective LED light-based photocatalytic system that can be used at room temperature to break down those key carbon-fluorine bonds. The system is an improvement over traditional chemical manufacturing processes that typically require high temperatures to achieve similar results.

Work at CSU was led by Professor Garret Miyake in the Department of Chemistry. His team partnered with fellow CSU chemistry Professor Robert Paton as well as Professor Niels Damrauer at the University of Colorado Boulder on the paper.

Miyake said complementary expertise across those teams led to this high-impact interdisciplinary research finding.

"Our approach is a fundamental advancement in organic synthesis that achieves activation of these challenging carbon-fluorine bonds across a variety of situations," he said. "Our method is more sustainable and efficient and can be used to address stubborn compounds in plastics, for example, in addition to the obvious uses around PFAS."

Most people in the world have been exposed to PFAS by touching or eating materials containing them. A common source of exposure is drinking water, but the compounds can also be found in non-stick consumer products, food packaging, and common manufacturing processes.

Research led by the EPA shows that even low-level exposure can result in developmental effects like low birth weight or reduced immune response, among many other health issues.

Postdoctoral researcher Mihai Popescu served as an author on the paper and contributed to the mechanistic understanding of the research using computational chemistry. He said the next challenge will be in taking the technology and preparing it for application in the field across many instances.

"We need to make this technology more practical so it can be used in water or soil—places where PFAS are found," said Popescu. "We need the chemistry we are showcasing here to be useful in those conditions and that is where a lot of work remains."

Miyake currently serves as director of the Center for Sustainable Photoredox Catalysis (SuPRCat) on campus. That center was launched in 2023 with the goal of developing chemical manufacturing processes that harness light energy and utilizing readily available materials as catalysts.

Miyake noted that similar research projects to the one discussed in the paper are happening every day through the center. Postdoctoral researcher Xin Liu—who led the synthetic development of this work and is also a member of SuPRCat—said the work holds many possibilities.

"This paper deals specifically with forever chemicals, but our approach in SuPRCat to using LED lights presents a host of possibilities towards achieving these reactions in a more sustainable and efficient way," said Liu.

"From dealing with plastics that don't degrade quickly to improving the manufacturing process of needed fertilizers, this is a key area and something CSU is well positioned to lead on."

More information: Photocatalytic C‒F bond activation in small molecules and polyfluoroalkyl substances, Nature (2024). DOI: 10.1038/s41586-024-08327-7

Journal information: Nature

Provided by Colorado State University