Environment

Hydrogen and UV breaks down toxic PFAS "forever" chemicals in water

A new technique can break down 95% of toxic "forever chemicals" in water
A new technique can break down 95% of toxic "forever chemicals" in water

PFAS are among the most insidious pollutants, thanks to their ubiquity, their long life and their growing list of linked health concerns. But now researchers at the University of California, Riverside have developed a new method to break them down more effectively, using hydrogen and UV light.

PFAS is a group containing thousands of chemicals that are heat-resistant and water-repelling, and so have been commonly used for decades in everyday items like non-stick cookware, food packaging and waterproof clothing. Unfortunately, these chemicals are increasingly being linked to a range of health problems, such as cancer.

In further bad news, PFAS is made up of very stable molecules, giving them a long life and the nickname of “forever chemicals.” All up, that makes exposure hard to avoid, with a recent study finding that PFAS levels in rainwater all over the world exceed the threshold that the EPA considers safe.

As such, finding ways to break down these chemicals is a key area of research. Recent advances include using supercritical water or chemical reactions that target the “Achilles’ heel” of the molecules, but the most common method is to add a catalyst then expose the mix to ultraviolet light.

The new method falls under the same broad category. First, extra hydrogen is added to water contaminated with PFAS, which polarizes the water molecules and makes them more reactive. Then, exposure to UV light triggers chemical reactions that break down the pollutants.

In tests, the technique was found to boost the degradation of one PFAS form, called PFOA, from 10% to 95% compared to other UV treatment methods, and defluorinate up to 94% of the molecules. Importantly, the team says that no dangerous byproducts are created in the process.

“After the interaction, hydrogen will become water,” said Haizhou Liu, corresponding author of the study. “The advantage of this technology is that it is very sustainable.”

The team has received a grant to work on scaling up the technology to test it on larger volumes of water, with the hope that it could eventually be used to treat drinking water and industrial wastewater.

The research was published in the Journal of Hazardous Materials Letters.

Source: UC Riverside

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3 comments
Expanded Viewpoint
Now THAT is some interesting science going on there!! But where is the Oxygen coming from to combine with the Hydrogen to make more water? Why not just electrify the water while shining the UV light through it, why does there have to be a sub step involved? Or use a water splitter and pull the Hydrogen out of the water, do the PFAS reaction thing with the UV light, then near the top of the water column, pump the Oxygen back in and combust them back into water again? And inject the free Hydrogen at two different places in the water column to catch any remnants from the first exposure.
Catweazle
PFAS are Perfluoroalkyl and Polyfluoroalkyl Substances, the fluorine is the risky bit.
So what are the degradation products, at least one must be a fluorine compound?
Tanoca
I don't understand why these PFAS AND single use plastics (which we're lied that they're recycled) are still not banned all over the world. Our bodies will turn into chemical and microplastic dumps as our oceans after one or two decades. And it will affect EVERYBODY. How can we (human beings) be this stupid?