3 ms·

Sounds very energy intensive compared to other methods being researched. I am also wondering: what is the mechanism of breakdown of the molecules?

• philipkglass 3y ago
  It's an open access research article so you can see the full text of the original here: "Mechanochemical destruction of per- and polyfluoroalkyl substances in aqueous film-forming foams and contaminated soil" https://pubs.rsc.org/en/content/articlelanding/2023/VA/D3VA00099K https://pubs.rsc.org/en/content/articlelanding/2023/VA/D3VA0... This is the most relevant paragraph for understanding the mechanism: We have recently studied the degradation of perfluorosulfonic acid (PFSA) standards under mechanochemical destruction (MCD) conditions on quartz sand, which highlighted the radical-mediated degradation pathway of these compounds ultimately resulting in the formation of stable Si–F bonds embedded in the silica matrix. Other studies have also established the effectiveness of MCD to destroy a variety of topical persistent PFASs under laboratory conditions. This degradative phenomenon can be explained by the mechanical activation of the matrix and the generation of highly reactive surface sites on freshly formed surfaces which initiate and propagate the mineralisation of organic substances, such as PFASs. Naturally occurring minerals in sandy soil form very reactive surfaces in the instant after they are broken into fragments by milling. Normally those surfaces quickly react with other materials in the immediate environment (natural organic matter, moisture, other minerals). That's why you can't just grind up a bunch of silica and add it to PFAS afterward to get a decontamination effect. But if the contaminated soil is ground up, minerals and all, part of that reactive mineral surface reacts with PFAS contaminants. The organic fluorine chemicals get turned into thermodynamically stable mineralized fluorides, so a little change each second compounds into near-perfect PFAS removal with prolonged application.