research news
UB researchers think plasma treatment can make dirty PFAS filters reusable
From left: UB researchers Joshua Wallace, Steven Ray and Alexander Hoepker are developing a plasma treatment system to remove PFAS from filters and destroy them. Photo: Douglas Levere
By TOM DINKI
Published June 9, 2025
It’s known as granular activated carbon, or GAC. Whether deployed in a water treatment plant or the pitcher in your fridge, this highly adsorbent organic material can easily capture water pollutants.
It can even capture per- and polyfluoroalkyl substances (PFAS), better known as “forever chemicals.”
“The question becomes what to do with that GAC now that it’s covered in forever chemicals,” says Steven Ray, associate professor of chemistry and an affiliated faculty member of the UB RENEW Institute. “Because if you simply throw it in a landfill, the PFAS are just going to leach and contaminate water again.”
Ray has received a $250,000 Strategic Environmental Research and Development Program (SERPD) grant from the U.S. Department of Defense to thermally remove PFAS from GAC. This will involve a novel, commercially available plasma system that will destroy PFAS and transform them into harmless fluorine salts.
This would allow GAC to be reused, benefiting not only the DoD but also the many municipalities throughout the country that have installed or are planning to install large-scale GAC filtration systems.
“There’s obviously a desire to recycle these massive and costly filters, and this method can hopefully do that,” says RENEW senior research scientist Alexander Hoepker, who is a co-investigator on the grant along with fellow RENEW senior research scientist Joshua Wallace.
Granular activated carbon (GAC) filters, like the ones found in home water pitchers, can capture water pollutants like forever chemicals. UB researchers are developing a plasma treatment that will remove forever chemicals from GAC filters so they can potentially be reused.
The process they’re developing involves converting captured PFAS molecules into vapor in order to free them from the GAC and then destroying the vapor with a specialized microwave plasma.
Microwave plasma is formed in the ambient air using high-energy microwaves supplied by components typically used in microwave ovens. The plasmas can reach temperatures between 5,000 and 7,000 degrees Celsius, about the temperature of the surface of the sun, and have destructive efficacies of 99.9%.
“The temperatures and the energetics of plasmas are so high that even the carbon-fluorine bonds of PFAS, which are notoriously difficult to break, are destroyed,” says Ray, the grant’s principal investigator. “They’re atomized.”
The DoD has banned the incineration of PFAS, in part because it relies on natural gas and creates harmful byproducts.
“Natural gas is already a source of carbon, and carbon is exactly what you don’t want the released fluorine to reform with,” Ray adds. “The byproducts from a flame are very complex, whereas the byproducts from a plasma can be very, very simple.”
Some of those simple byproducts are minerals. The plasma system will destroy the PFAS and then capture the fluorine by mineralization, allowing it to be reused.
“The released fluorine could potentially combine with calcium, creating the calcite you find in rocks,” Hoepker says. “We’re essentially converting PFAS into natural minerals that can be repurposed.”
The team hopes their plasma system could eventually work directly on soils contaminated with PFAS.
“Lots of research has focused on degradation of PFAS in water, an important and massive undertaking, but just a small number of groups are trying to degrade PFAS in solids. Our project is really a complete departure from typical PFAS research,” Hoepker says. “There’s been a big technological gap in degrading PFAS in solids, and so we aim to fill it.”