Scientists discover a way to destroy permanent chemicals

So-called permanent chemicals in everyday items like nonstick pans have long been linked to serious health problems, and scientists now say they’ve figured out how to combat them.

Chemists from the United States and China announced Thursday that they have discovered an innovative way to break down these polluting compounds, known as PFAS, using relatively low temperatures and common reagents.

Their findings were published in the journal Science and may represent a solution to a permanent source of damage to the environment, livestock and people.

“That’s really why I’m doing science, to have a positive impact on the world,” lead author William Dichtel of Northwestern University told reporters at a press conference.

PFAS, or perfluoroalkyl and polyfluoroalkyl materials, were first developed in the 1940s and are now found in a variety of products including nonstick pans, waterproof textiles, and fire-extinguishing foams.

Over time, pollutants spread and accumulated in the environment, penetrating the air, soil, groundwater, lakes and rivers as a result of industrial processes and degradation in landfills.

A study published last week by scientists at Stockholm University shows that rainwater across the planet is unsafe to drink due to PFAS contamination.

Chronic exposure – even at low levels – has been linked to liver damage, high cholesterol, poor immune response, low birth weight and several types of cancer.

While PFAS chemicals can be filtered out of the water, there are few solutions to get rid of them once they’re out.

Ten minus, thousands left

Current methods of destroying PFAS require extensive treatments, such as burning at extremely high temperatures or ultrasonic irradiation. The indestructibility of PFAS is due to the carbon-fluoride bonds, which are one of the strongest bonds in organic chemistry.

Fluorine is the most electronegative element and collects electrons, while carbon seeks to share them. PFAS molecules contain long chains of these bonds, but the scientists found a weak point.

At one end of the molecule are oxygen atoms that can be attacked with a common solvent and reagent at temperatures from 80 to 120 °C, thus cutting off the head of the molecular group and leaving a reactive tail.

The second part of the study focused on using powerful computational methods to map the quantum mechanics behind the chemical reactions the team conducted to destroy molecules.

“When this happens, you can access previously unrecognized pathways, which cause the entire molecule to disintegrate in a complex series of reactions,” Dichtel said, making the end products ultimately benign. The new action could eventually lead to improvements in the method of destruction.

The current study focused on 10 PFAS chemicals, including a contaminant called GenX, which polluted the Cape Fear River in North Carolina.

But that’s just the tip of the iceberg, as the US Environmental Protection Agency has identified more than 12,000 chemicals from PFAS. “There are other classes that don’t have the same Achilles heel, but each one has its own vulnerability. If we can identify them, we will know how to activate them to destroy them,” Dichtel said.