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Poly- and perfluoroalkyl substances (PFAS), these eternal pollutantsinfamous, are now a major environmental challenge. Discovered over 80 years ago, they are ubiquitous, highly persistent, and found in a myriad of products, from kitchen utensils to firefighting foams. Problem: they are highly toxic to humans (cancers, hormonal disorders, fertility problems, effects on fetal development, etc.) and to the environment.
Highly mobile in ecosystems, they accumulate in organisms and decontamination operations are complex and costly. However, new work, published in the journal Angewandte Chemie International Edition, , opens up new perspectives for their elimination. Researchers at Ritsumeikan University in Japan have developed a novel method, combining visible LED light and semiconductor nanocrystals to destroy PFAS.
A luminous process: how LED light breaks down PFAS
This cutting-edge technique is based on a photocatalytic reaction (a process in which light transforms pollutants into harmless products) triggered by LEDs emitting at 405 nm. The team of researchers designed a process using copper-modified cadmium sulfide (CdS) nanocrystals, combined with triethanolamine (TEOA) and water.
When a PFAS compound, such as perfluorooctanesulfonate (PFOS), is introduced into this solution and subjected to LED lighting, a reaction takes place. The nanocrystals, excited by light, attract the PFOS molecules and break their carbon-fluorine bonds, thus allowing the elimination of fluorine ions and the complete decomposition of these recalcitrant pollutants.
In just eight hours, scientists achieved total iron removal of their PFOS samples. Yoichi Kobayashi, professor of applied chemistry and lead author of the study, explains: “ The proposed method appears promising for efficiently breaking down a whole range of perfluoroalkyl substances into softness “.
The team also achieved the feat of remove 8 1% of the fluorine ions from Nafion, a fluoropolymer used as an ion exchange membrane, after 24 hours of irradiation, thus broadening the field of ’ #8217;application of this technology.
200% Deposit Bonus up to €3,000 180% First Deposit Bonus up to $20,000A gentle and effective alternative to traditional methods
Until now, the removal of PFAS required extreme temperatures, around 400°C, making the process expensive and energy-intensive. However, this technique developed by Ritsumeikan University stands out for its simplicity of execution and its effectiveness at much milder temperatures, around 38°C.
In addition, the thermal degradation of PFAS can also lead to the formation of by-products, which can themselves be toxic or persistent in the environment. Without these excessive temperatures, the probability of releasing these by-products is then eliminated.
This ingenious approach offers a viable and ecological alternative to treat these pollutants, whose deleterious impact on human health and the environment has been proven since the 1960s.
Sustainably Recycling Fluorine
The critical importance of this discovery lies not only in its ability to break down PFAS, but also in its potential to recycle fluorine. By isolating fluorine ions, this method makes it possible to recover a key component that is widely used in clean energy and the pharmaceutical industry.
Kobayashi emphasizes that further refinements could significantly improve this technique. Traditionally, fluorine recycling processes require specialized equipment and very strict safety conditions, which also makes them very expensive.
In addition, fluorine-containing materials are often complex and heterogeneous, which complicates their processing and there is currently no mature technique for efficiently recycling this compound.
This Japanese advance is therefore part of a broader dynamic aimed at developing environmentally friendly decontamination technologies. Of course, the path to large-scale deployment of this technique is still long and there is a probability that it will never even be used. This solution may not be economically viable and its industrialization may never take place, but the efforts of the Japanese team are still to be commended.
- Japanese researchers have developed a technique using LED light and nanocrystals to effectively break down PFAS.
- This method works at room temperature and is gentler than conventional decontamination methods.
- By isolating fluorine ions, this method opens up new perspectives for the recycling of an essential element widely used in industry.
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