Figure 1: Chemical structure of PFAS (Source)
Per- and Polyfluoroalkyl Substances (PFAS), infamously known as “forever chemicals,” are found in many industry branches, such as cookware, paints, and cosmetics. Characterized by their robust carbon-fluorine bonds, PFAS has remarkable resistance to water and extreme temperatures. Its durability poses a significant threat to water and soil ecosystems worldwide and potentially to human health, challenging scientists to discover effective PFAS removal and destruction methods.
Currently, high-temperature technologies including incineration and thermal oxidation—some of which operate at temperatures over 1,000˚C—are predominantly used to destroy PFAS. However, these methods can be costly and yield toxic, hazardous gasses.
Recently, chemists have explored innovative PFAS destruction techniques that address these issues, including boiling with dimethyl sulfoxide (DMSO) and electrochemical oxidation.
Researchers at Northwestern University have found that DMSO, a commonly used and inexpensive solvent, serves as the key to breaking down PFAS. By subjecting a mixture of PFAS and DMSO to boiling temperatures, the carbon-oxygen head of PFAS molecules becomes detached, weakening the remaining carbon-fluorine bonds. The researchers also found that introducing sodium hydroxide (NaOH) to the mixture can enhance the destruction process. NaOH readily bonds with the fragmented PFAS molecules as they break apart, facilitating their dismantling.
Scientists at the Swedish University of Agricultural Sciences have explored electrochemical oxidation as another promising method to destroy PFAS. Their research demonstrates that employing high current densities through electrochemical oxidation can effectively oxidize the robust carbon-fluorine bonds within PFAS chains, ideally resulting in the production of carbon dioxide and fluoride.
Furthermore, emerging PFAS destruction methods include supercritical water oxidation, which uses heat and pressure to eliminate solid, short-chained PFAS, and hydrothermal alkaline treatment, leveraging alkalinity to degrade liquid-waste PFAS under less extreme conditions.
Yet not only scientific breakthroughs but also political initiatives are striving to address the hazardous chemicals. The Environmental Protection Agency (EPA), under the Biden-Harrison Administration, has taken several actions to address the PFAS crisis.
EPA’s announcement of the availability of $2 billion in funds from President Biden's Bipartisan Infrastructure Law aimed at tackling emerging contaminants like PFAS in the nation’s drinking water systems. In March, the EPA proposed legally enforceable levels for the six PFAS chemicals prevalent in drinking water, establishing a “nationwide, health-protective standard for PFAS in drinking water.”
They have also introduced various measures to improve data collection and transparency regarding PFAS. This includes the release of the PFAS Analytic Tools in January 2023, an interactive webpage that consolidates PFAS information sources for the public, researchers, and stakeholders.
The combined efforts of scientific research and regulatory actions reflect a comprehensive commitment to addressing the PFAS crisis.
Works Cited
McCabe, Andy., and Ling, Ali. “Emerging PFAS destruction technologies”. Barr Engineering, 9 Mar. 2023. https://www.barr.com/Insights/Insights-Article/ArtMID/1344/ArticleID/511/Emerging-PFAS-destruction-technologies
Trang, Brittany, et al. "Low-temperature Mineralization of Perfluorocarboxylic Acids." Science, 2022, https://doi.org/abm8868.
Verma, Sanny, et al. "Recent Advances on PFAS Degradation via Thermal and Nonthermal Methods." Chemical Engineering Journal Advances, vol. 13, 2023, p. 100421, https://doi.org/10.1016/j.ceja.2022.100421.
Zimmer, Carl. “Forever Chemicals No More? PFAS Are Destroyed With New Technique” The New York Times, 18 Aug. 2023, https://www.nytimes.com/2022/08/18/science/pfas-forever-chemicals.html
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