BEAUFORT, N.C.— At the inaugural Nicholas School Faculty Research Symposium at the Marine Lab on September 29th, professors from each of the school’s three academic divisions presented to NSOE colleagues their current work and its application in ongoing research. This is the second of six synopses of those presentations.
As the world endeavors to extricate itself from a carbon economy in favor of clean energy, Lee Ferguson, associate professor of civil and environmental engineering, is pursuing an unprecedented field of inquiry on bis-perfluoroalkyl sulfonimides (bis-FASIs), a primary electrolyte in lithium-ion batteries (LiBs), and has himself walked miles on the frozen Mississippi River, at its Minnesota headwaters, to ensure responsible progress toward clean energy.
Ferguson, who is chair of the Nicholas School’s Master of Environmental Management (MEM) program in Ecotoxicology and Environmental Health, has spent 20 years amassing data on emerging pollutants in the environment. A major focus of his work has been per- and polyfluoroalkyl substances (PFAS), long-lasting compounds –often called “forever chemicals”—that are widely used in the production of carpet coatings, food wrappers, fire-retardant foams, and industrial surfactants.
Because of their ability to resist decay and decomposition, PFAS can persist in the environment for decades and are known to be accumulating in North Carolina water systems.
The effect of the presence of PFAS in solar collectors, windmill coatings, and electric-vehicle batteries has been a question largely ignored, prompting Ferguson to expand the scope of his work.
At last Friday’s symposium, he presented “The Next Frontier in Forever Chemicals: Environmental Implications of Clean Energy,” describing unexpected results when a research team, co-led by Jennifer L. Guelfo at Texas Tech University, extracted and examined lithium-ion battery components in the laboratory using high-resolution mass-spectrometry techniques (e.g. UHPLC-Orbitrap MS/MS), and then went into the field to test for those components in targeted water sources.
The project took Ferguson and Guelfo to Minnesota and Kentucky, and also to Antwerp, Belgium, and Salindres, France, to examine rivers and creeks around some of the world’s most important PFAS manufacturing sites. In Minnesota, in January 2022, the team hiked five miles down the Mississippi, near one of the U.S.’s largest fluorochemical manufacturing plants, drilling holes in the ice and taking water samples close to the plant’s outfall, to measure occurrence of bis-FASIs and other PFAS.
Their findings showed bis-FASI were present in water and sediment near discharges, and were even measured in soil, indicating atmospheric transport.
As the first study to directly address the environmental impact of manufacturing and use of bis-FASIs in LiBs, Ferguson and his colleagues are investigating questions not yet on the U.S. Environmental Protection Agency’s radar. The Minnesota plant, for example, is already under scrutiny for PFAS release, and has instituted related controls; yet, current safeguards fail to fully remove novel LiB-associated, bis-FASIs, which may be very difficult to treat using conventional water treatment methods.
The study has global implications as demand for clean energy sources soars. Demand for lithium-ion batteries, for instance, has increased exponentially since 2016, matching the growing use of electric vehicles, cell phones, laptops and medical devices. Today, only 5% of LiBs are recycled; bis-FASIs have been found in municipal solid-waste landfill leachate.
“I try to look at water from the perspective of a fish,” Ferguson said. “Why should we be worried about pollution from bis-FASIs? The aliphatic fluorine-carbon bond is the strongest bond in organic chemistry. It makes these compounds virtually undegradable. Once they’re in our environment, they really are forever.”
“It’s an open question,” he said, “whether clean energy is, really, clean.”