A potential solution may lie in a new method developed by scientists at ETH Zurich to break down PFAS—a class of synthetic and persistent chemicals found in common household items—by using nanoparticles and ultrasound. This new technology could mean the beginning of an era in improved environmental sustainability.
Tackling the Unbreakable
Per- and polyfluoroalkyl substances (PFAS) are a class of man-made chemicals which have gained international attention. These “forever chemicals” are present in a range of everyday products, including firefighting foam and non-stick cookware.
The issue is their persistence — the carbon-fluorine bonds in PFAS are nearly unbreakable so they do not break down easily. The conventional methods of decomposing these chemicals by heat or photocatalysis are either energy-intensive or ineffective.
Now, however, researchers at ETH Zurich have come up with a new process which could revolutionise this state-of-affairs. With the use of piezoelectric nanoparticles and ultrasound, they have made a break-through which allows mechanical energy to be turned into power, in such a way made to degrade PFAS, in particular perfluorooctane sulfonates (PFOS).
The Piezoelectric Heart of ESA’s ElectronicNose
This revolutionary technique is based on nano-scale materials, these nanomaterials are not conventional ones and because of its different physical and chemical properties they have a unique electrochemistry signal. The smallest ones were the size of sand grains–invisible to the naked eye and piezoelectric. What they do is generate an electrical charge when you bend them (mechanical deformation).
Here, the piezoelectric nanoparticles are spread in an ultrasonic bath, which is finished with the mechanical energy of high frequency ultrasound waves and energized. The electrical charge triggers a cascade that sunder the PFOS molecule into pieces.
In water samples with 4 mg per liter of PFOS, the piezocatalytic process was able to break down 90.5% of the chemical, Andrea Veciana, another doctoral student working on the project, said. Although this is a tremendous feat, the scientists claim that in lakes and rivers, where PFOS concentrations are much lower than contamination sites, the rate of degradation would be considerably slower.
Conclusion
But this way of using piezoelectric nanoparticles and ultrasound offers a new well-founded hope for the PFAS problem. In addition to providing a unique and innovative system for breaking down these “forever chemicals,” this method leverages mechanical energy, rather than traditional chemical solvents, which is not only more efficient but also better for the environment. Scalability is deemed as the weak part but its prospective to fight PFAS and other micropollutants are ascertained. With increasing global pressure to regulate PFAS and improve transparency, this research might go a long way towards ensuring a cleaner, safer world for everyone.
