Fire-fighting foams, non-stick cookware, water-repellent textiles and pesticides all have one thing in common: they all contain so-called PFAS (per- and polyfluorinated alkyl substances) - human-made chemicals that do not degrade naturally. So it's no wonder that PFAS are now contaminating soil and water and can also be detected in the bodies of humans and animals. The dangers are well known: These forever chemicals can damage the liver, trigger hormone disruption and cause cancer, to mention just a few of their effects.<\/p>\n
To break up the PFOS molecules and thus degrade them in water, the researchers used piezocatalysis for the first time. \u201cPiezo\u201d refers to piezoelectricity, an electrical charge that is generated during mechanical deformation, and \u201ccatalysis\u201d means accelerating a chemical reaction with suitable substances. \u201cWe\u2019ve developed nanomaterials that are piezoelectric. To the naked eye, this material looks a bit like sand,\u201d Veciana says. In the ultrasonic bath, these particles become electrically charged and act as a catalyst. Pan\u00e9 i Vidal adds: \u201cIt\u2019s this electrical charge that sets the whole chain of reaction in motion and breaks down the PFOS molecules piece by piece. That\u2019s why the nanoparticles are called piezoelectric.\u201d To measure the PFOS concentration in their samples, the researchers worked with Samy Boulos, analytical specialist from the Laboratory of Food Biochemistry. Using a mass spectrometer, the researchers were able to prove that 90.5\u00a0percent of the PFOS molecules were degraded. \u201cHowever, we should point out that we were working with a very high concentration of 4 milligrams per litre,\u201d Veciana says. \u201cIn the natural world, such as in lakes and rivers, the PFOS concentration is less than 1 microgram per litre. And the lower the concentration, the longer it takes for the PFOS to degrade.\u201d Some of the technologies currently in development first concentrate the water and then destroy the PFOS. This would also be a key step in the piezocatalysis, one that would have to be implemented in a specific application such as a chemical industry effluent.<\/p>\n
The potential of the new method becomes clear when considering the existing options for degrading PFAS. \u201cOne method is thermal decomposition, but that requires a temperature of over 1,000 degrees Celsius, which makes it highly energy intensive,\u201d Veciana says. PFAS can also be degraded by photocatalysis. This process is similar to piezocatalysis but uses light for activation of the catalyst instead of mechanical energy. The main problem with this method is that in practice, the objective is to treat wastewater, and since wastewater is cloudy, there is a low light penetration. Veciana mentions a third method: \u201cThere\u2019s also absorption, where you use a kind of sponge to soak up the pollutants from the water. But this merely shifts the problem from one place to another; now you need a solution for the PFAS-permeated sponge.\u201d The disadvantages of the existing methods were one of the reasons the ETH researchers went looking for a new way to break down PFAS. Piezocatalysis has the advantage of being able to work with different sources of mechanical energy. \u201cIf water has to be purified in wastewater treatment plants and there\u2019s already turbulence in the water, that energy could perhaps be harnessed to break down the PFAS in it,\u201d Veciana says.<\/p>\n
Unfortunately, what the researchers have achieved in the laboratory with water samples of 50 millilitres hasn\u2019t yet been transferred into practice. \u201cThe scalability of our method is one of the biggest challenges,\u201d Pan\u00e9 i Vidal says. \u201cHowever, we\u2019ve succeeded in showing that piezocatalysis works as a method for degrading PFOS and has advantages over previous methods.\u201d Furthermore, their method can not only be used on PFOS, but on any other PFAS and micropollutant. In general, methods for degrading PFAS should be used before the chemicals get into the environment, i.e. in industrial wastewater treatment plants, or on collected agricultural water for reuse. \u201cCompanies should take all possible measures to ensure that the water they release into the environment is as clean as possible,\u201d Pan\u00e9 i Vidal says. Veciana adds: \u201cPFAS are a global problem that should be tackled first and foremost through policy change and more transparency.\u201d There\u2019s already a lot of media coverage about a PFAS ban and stricter regulations to force the industry to be more transparent about the use of these chemicals. Veciana says: \u201cNevertheless, it\u2019s also important to continue to innovate through research in order to reduce and remediate the existing exposure to PFAS as much as possible.\u201d \u00a0 Originally published Small Science 2400337<\/p>\n
Veciana A et al. (2024) - Breaking the Per\ufb02uorooctane Sulfonate Chain: Piezocatalytic Decomposition of PFOS Using BaTiO3\u00a0Nanoparticles<\/a> \u00a0<\/p>\n Source: ETH Z\u00fcrich News<\/a> Researchers at ETH Zurich have developed a new method to break down a dangerous subgroup of PFAS, known as PFOS. With the help of nanoparticles and ultrasound, piezocatalysis could offer an effective alternative to existing processes in the future.<\/p>\n","protected":false},"author":22,"featured_media":20868,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[42],"tags":[],"class_list":["post-20873","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-innovation-society"],"_links":{"self":[{"href":"https:\/\/innovationsgesellschaft.ch\/en\/wp-json\/wp\/v2\/posts\/20873","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationsgesellschaft.ch\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/innovationsgesellschaft.ch\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/innovationsgesellschaft.ch\/en\/wp-json\/wp\/v2\/users\/22"}],"replies":[{"embeddable":true,"href":"https:\/\/innovationsgesellschaft.ch\/en\/wp-json\/wp\/v2\/comments?post=20873"}],"version-history":[{"count":2,"href":"https:\/\/innovationsgesellschaft.ch\/en\/wp-json\/wp\/v2\/posts\/20873\/revisions"}],"predecessor-version":[{"id":20875,"href":"https:\/\/innovationsgesellschaft.ch\/en\/wp-json\/wp\/v2\/posts\/20873\/revisions\/20875"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/innovationsgesellschaft.ch\/en\/wp-json\/wp\/v2\/media\/20868"}],"wp:attachment":[{"href":"https:\/\/innovationsgesellschaft.ch\/en\/wp-json\/wp\/v2\/media?parent=20873"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/innovationsgesellschaft.ch\/en\/wp-json\/wp\/v2\/categories?post=20873"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/innovationsgesellschaft.ch\/en\/wp-json\/wp\/v2\/tags?post=20873"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Image source: Canva<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"