United States: Because of their extreme toxicity and extreme resistance to breakdown as waste products, "forever chemicals" found in everyday items such as non-stick pans have long been associated with serious health problems.
On Thursday, chemists from China and the United States announced that they had finally discovered a key technique for PFAS degradation using common reagents and relatively low temperatures.
Their findings, which may provide a remedy for long-term damage to the environment, livestock and people, were published in the journal Science.
"I really do science by having a positive impact on the world," William Dichtel, a senior author at Northwestern University, told reporters at a news conference.
PFAS, or per- and polyfluoroalkyl substances, were created in the 1940s and are now present in a wide range of items such as fire extinguishing foams, water-resistant fabrics, and nonstick cookware.
As a result of industrial processes and landfill leaching, pollutants have accumulated in the environment over time, entering the air, soil, groundwater, lakes and rivers.
Researchers at Stockholm University discovered last week that PFAS contamination makes rainwater everywhere on Earth unsafe to drink.
Even low levels of chronic exposure have been linked to liver damage, high cholesterol, a weakened immune system, low birth weight and various cancers.
Although PFAS chemicals can be removed from water by filtration, there are not many effective ways to get rid of them after that. PFAS currently must be destroyed using harsh processes such as ultrasonic irradiation or burning at extremely high temperatures.
Carbon–fluoride bonds, one of the strongest types of bonds in organic chemistry, are what give PFAS their indestructibility. The most electronegative element, fluorine, seeks electrons while carbon is eager to release them.
Long chains of these bonds are present in PFAS molecules, but the research team was able to pinpoint an obvious defect shared by a particular class of PFAS.
At low temperatures of 80 to 120 °C (176–248 °F), a common solvent and reagent can be used to target a group of charged oxygen atoms at one end of the molecule, causing the head group to break off. and a reactive tail is left behind. ,
When this happens, previously unknown pathways become accessible, Dichtel said, which eventually leads to the production of benign end products as the entire molecule disintegrates in a series of complex reactions.
In the second part of the study, the team used sophisticated computational techniques to visualize quantum mechanics underlying the chemical reactions carried out to destroy the molecules.
Future progress for the process may be guided by new information.
The current study focused on 10 PFAS substances, including GenX, for example, a significant pollutant, which has contaminated the Cape Fear River in North Carolina.
The US Environmental Protection Agency has identified more than 12,000 PFAS chemicals, so this is only the tip of the iceberg.
According to Dichtel, other classes may not have the same Achilles heel, but they all have their own weaknesses.
"If we can find it, we can use it to our advantage to destroy it."
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