A method discovered to destroy certain “eternal pollutants”
PFAS, called “eternal” because of their extreme resistance and toxicity, are harmful and have spread, over time, in our environment.
PFAS, which disintegrate extremely slowly, are found in packaging, shampoos, non-stick pans and even make-up. (illustrative image)
AFP
Scientists announced Thursday that they have found a method to destroy certain pollutants, called “eternal” because of their extreme resistance and toxicity, which are present in many everyday objects and can cause serious health problems.
The technique, which requires relatively low temperatures and so-called common reactants, was developed by chemists in the United States and China whose work has been published in the journal ‘Science’, offering a potential solution to a persistent problem for the environment, livestock and people.
Developed in the 1940s, PFAS (per- and polyfluoroalkyl substance groups), which disintegrate extremely slowly, are found in packaging, shampoos, non-stick pans and even make-up. Over time, they have spread through our environment: water, soil, air, groundwater, lakes and rivers.
Quasi indestructible
A Swedish study showed last week that rainwater was undrinkable everywhere on earth due to too high a level of PFAS. According to some studies, exposure to PFAS can have effects on fertility and fetal development. It can also lead to increased risks of obesity or certain cancers (prostate, kidneys and testicles) and an increase in cholesterol levels.
Current methods for degrading these pollutants require powerful treatments, such as very high temperature incineration or ultrasonic irradiation. Their almost indestructible character is linked to the long carbon-fluorine bonds that compose them, among the strongest in organic chemistry.
However, the researchers managed to identify a weakness in certain types of PFAS: at one end of their molecule, a group of oxygen atoms can be targeted by a solvent and a common reagent at average temperatures of 80 to 120 degrees Celsius. When this happens, “it causes the entire molecule to collapse in a cascade of complex reactions,” says William Dichtel of Northwestern University, one of the study’s authors.
“Everyone has their own weak point”
Scientists have also used powerful computational methods to map the quantum mechanics behind these chemical reactions. Work that might possibly be used to improve the method. The current study focused on 10 PFASs, including a major pollutant named GenX, which contaminated the Cape Fear River in North Carolina.
But there are more than 12,000 “eternal chemicals”, according to the US Environmental Protection Agency. “There are other types (of PFAS) which do not have the same Achilles heel but each has its own weak point, underlines William Dichtel. If we can identify it, then we will know how to activate it to destroy it.”
AFP
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