The list of items that contain PFAS – “forever chemicals” – is long and frightening: our clothing, food packaging, firefighting foams, nonstick cookware, building products, and makeup, among many others. (Even our dental floss has “forever chemicals” in it!)
University of Rochester scientists have found a way to clean up some of those “forever” chemicals through electrochemical processes using nanocatalysts.
The researchers focused on a specific type of PFAS called Perfluorooctane sulfonate (PFOS). These substances were widely used in stain-resistant products until the 2000s, although many countries have banned them due to their harm to humans and animals. Unfortunately, the PFOS are still prevalent in our environment – mainly our water supplies.
The team, materials science PhD students led by assistant professor of chemical engineering Astrid Müller, used ultrafast lasers, chemistry, and chemical engineering to develop their nanocatalysts.
“Using pulsed laser in liquid synthesis, we can control the surface chemistry of these catalysts in ways you cannot do in traditional wet chemistry methods,” says Müller. “You can control the size of the resulting nanoparticles through the light-matter interaction, basically blasting them apart.”
Once blasted, the scientists adhered the nanoparticles to carbon paper that is hydrophilic (attracted to water molecules). The paper is a cheap substrate with a large surface area, allowing them to use lithium hydroxide at high concentrations to defluorinate the PFOS chemicals.
Scientists must treat a cubic meter of water at a time for this process to work at scale. Fortunately, the approach uses nonprecious metals, unlike existing methods that use boron-doped diamonds. The current process would cost $8.5 million to treat a cubic meter of polluted water. The new process is nearly 100 times cheaper.
The team published their study in the Journal of Catalysis.
