110 Degrees: New Method Breaks Down PFAS Without High-Heat Incineration

Contaminated water is often filtered to remove harmful chemicals, but the process leaves those substances trapped in solid materials. If those solids are not destroyed, the pollution simply moves from one waste stream to another, rather than disappearing. Engineers at the University of Utah have developed a technique to break down these persistent compounds under mild conditions, aiming to close that gap in the cleanup process.

The target compounds are per- and polyfluoroalkyl substances, commonly known as PFAS. These chemicals are known as "forever chemicals" because their strong carbon-fluorine bonds make them resistant to natural breakdown. They persist in the environment and pose long-term risks to public health. The new method addresses the destruction phase, which has historically been difficult to achieve without extreme heat or complex equipment.

Ling Zang, a distinguished professor in the Department of Materials Science & Engineering and associate dean for research at the John and Marcia Price College of Engineering, led the study. Zang previously focused on removing PFAS through filtration and adsorption. This new work builds on that foundation by introducing a way to destroy the chemicals once they have been collected. The research was funded by Gentex Corp., a company on whose board of directors Zang sits.

The team used reactive chemicals called nucleophiles to sever the strong carbon-fluorine bonds in a process called defluorination. This reaction released nearly all of the fluorine as fluoride from several tested compounds. These included PFOA and trifluoroacetic acid, a small molecule that is particularly difficult to destroy. Defluorination is a central step in detoxifying these pollutants.

The method also worked on two fluorinated plastics, PVDF and PCTFE. These materials are commonly used in batteries, industrial products, and munitions. The ability to break down these specific plastics suggests the technique could apply to solid waste streams, not just liquid contaminants.

Most tests were conducted at temperatures of 110 degrees Celsius, or 230 degrees Fahrenheit. Some materials required temperatures up to 150 degrees Celsius. These conditions are substantially lower than the 1,000 degrees Celsius or higher often used for PFAS incineration. Lower temperatures reduce energy costs and may minimize the formation of secondary pollutants.

High-temperature incineration can produce smaller, more volatile fluorinated compounds if the breakdown is incomplete. These byproducts can disperse through the atmosphere, creating additional environmental concerns. The new method works in ordinary air and does not require inert gas atmospheres, deep-ultraviolet irradiation, or heavy-metal catalysts. It also avoids the need for externally applied high pressure or energy-intensive mechanical processing.

The study was published Oct. 28 in the journal Communications Chemistry under the title "Nucleophilic Defluorination of PFAS under Mild Conditions." Co-authors include Pallabita Basu, Saravanakumar Manickam, Rana Dalapati, Jiangfan Shi, Matthew Hunter, and Xiaomei Yang, all of the University of Utah’s Department of Materials Science & Engineering. Zang and two of the co-authors are listed as inventors on patent applications filed by the university in connection with the process.

The research remains at the laboratory stage. Future studies will explore alternative reagents and reaction conditions to improve effectiveness and reduce environmental impact. The team plans to evaluate the method using real waste streams, assess treatment costs, and determine the safety of the remaining products.

The results suggest a potential pathway for capturing PFAS from contaminated water, concentrating them into a smaller waste stream, and destroying them. This approach could prevent contamination from being transferred from water into another material.