New method rapidly degrades PFAS from spent adsorbents

A recent study published in ACS ES&T Engineering describes an innovative approach developed by Feng “Frank” Xiao and his team at the University of Missouri to efficiently eliminate PFAS (per- and polyfluoroalkyl substances) from the surfaces of granular activated carbon and anion exchange resins. PFAS are synthetic chemicals commonly found in various products, such as nonstick cookware, food packaging, and firefighting foam. The researchers employed a technique called thermal induction heating, which harnesses the Joule heating effect within a metallic reactor.

By adapting a method typically used for melting metals, the team achieved an impressive 98% degradation of PFAS on the surface of the absorbent materials within just 20 seconds. This breakthrough offers a highly energy-efficient and significantly faster alternative to conventional approaches.

PFAS exposure has raised concerns among experts due to potential health risks, including cancer and other serious ailments. While PFAS can be effectively filtered from water using absorbents, the disposal of spent adsorbents introduces environmental contamination challenges.

Focusing on environmentally safe PFAS removal, Xiao, a researcher in the Department of Civil and Environmental Engineering, has dedicated his career to investigating effective methods. In a recent study, he demonstrated the efficiency of induction heating for rapidly degrading PFAS in soil. The inspiration for this current study also stemmed from the Environmental Protection Agency’s (EPA) proposed regulations, which, if implemented, would require U.S. public water systems to monitor and reduce PFAS contamination in drinking water and spent adsorbents.

It’s important to note that the method does have potential drawbacks, including the creation of by-products during the process, such as organic fluorinated species and hydrogen fluoride. These by-products are considered toxic if inhaled or ingested. However, Xiao proposes a solution. If the gaseous organic fluorinated products are not degraded during induction heating, abatement treatment becomes necessary to remove or degrade them. Fortunately, based on his previous research, some of these products can be degraded using regular thermal methods. Additionally, the generation of hydrogen fluoride is increased, which is desirable as it promotes the mineralization or decomposition of PFAS. Xiao’s team found that hydrogen fluoride can be easily eliminated by employing clay or soil at moderate temperatures.

Source: University of Missouri

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