Scientists at the University of Rochester have developed new electrochemical methods to remove contamination from "forever chemicals" found in clothing, food packaging, firefighting foam, and a variety of other products. A new study in the Journal of Catalysis describes the development of nanocatalysts for the repair of per- and polyfluoroalkyl substances, known as PFAS.
The researchers, led by Astrid Müller, assistant professor of chemical engineering, are focusing on a special type of PFAS called perfluorooctane sulfonate (PFOS), which was once widely used in antifouling products but is now banned in much of the world due to its harm to human and animal health. Although PFOS was phased out by US manufacturers in the early 2000s, PFOS is still widespread and continues to appear in water supplies.
Müller and her team of PhD students in materials science have created nanocatalysts using her unique combination of expertise in ultrafast lasers, materials science, chemistry, and chemical engineering.
Using pulsed lasers in liquid synthesis, we can control the surface chemistry of these catalysts in a way that traditional wet chemistry methods can't," says Müller. "You can control the size of the nanoparticles produced by the interaction of light with matter, basically blowing them apart.
The scientists then adhered the nanoparticles to hydrophilic carbon paper. This provides an inexpensive substrate with a high surface area. They use a high concentration of lithium hydroxide to completely defluorinate the PFOS chemical.
Müller says that for the process to work on a large scale, they need to process at least one cubic meter at a time. Crucially, their new method uses all non-*** which is different from existing methods that require boron-doped diamonds. According to their calculations, treating one cubic meter of contaminated water with boron-doped diamond would cost $8.5 million; The new method is almost 100 times cheaper.
Use PFAS chemicals in a sustainable way
In future research, Müller hopes to understand why lithium hydroxide works so well and whether cheaper, more abundant materials can be substituted to further reduce costs. She also hopes to apply the method to a range of PFAS chemicals, which are still widely used but have been linked to health issues ranging from infant development to kidney cancer.
Despite these problems, Müller says that a complete ban on all PFAS chemicals and substances is impractical, as they are useful not only in consumer products, but also in green technologies.
I think that in the end, from geothermal heat pumps to efficient cooling to solar cells, a lot of decarbonization work depends on the availability of PFAS," says Müller. "I believe that if we can use PFAS in a circular, sustainable way if we can use electrocatalytic solutions to break fluorocarbon bonds and safely bring fluoride back into the environment without putting fluoride into the environment. ”
Although commercialization is still a long way off, Müller has filed a patent with the support of Urventures and expects the patent to be used in wastewater treatment facilities and used by the company to clean up the contaminated site where they once produced these PFAS chemicals. She also calls it a social justice issue.
Usually in lower-income areas around the world, there is more pollution," says Müller. "One of the advantages of the electrocatalytic method is that you can use it in a distributed way, using electricity from solar panels, in a small footprint.