Read the full article by Lars Fischer (Scientific American)
“Perfluorinated and polyfluorinated alkyl substances, or PFASs, are considered indestructible chemicals. They are virtually nondegradable and accumulate in humans and the environment. Suspected health effects include asthma, cancer and changes in the reproductive organs. How to get rid of PFASs has been completely unclear until now—and the first approaches to destroying the resistant molecules are showing promising results.
Heat is the key factor in breaking the carbon-fluorine bonds characteristic of this class of substances. In a study recently published in the Journal of Environmental Engineering, the U.S. Environmental Protection Agency found that a heat- and pressure-based technique known as supercritical water oxidation destroyed 99 percent of the PFASs present in a water sample.
The first attempts at using new methods to destroy these ‘indestructible’ substances offer at least some hope. In the new EPA study, experts added oxidizing substances to water contaminated with PFASs and heated the liquid above its critical temperature of 374 degrees Celsius at a pressure of more than 220 bars. During this process, the water becomes what is called supercritical: it is neither a gas nor a liquid. In this state, even water-repellent substances such as PFASs dissolve much more readily, and at the same time, the state accelerates chemical reactions. Various versions of this technique had previously been developed to break down different types of chemicals, but this is the first time it has been tested on PFASs in a peer-reviewed study.”…