2024-09-09 07:15:10
Water contamination from chemicals used in current technology is a rapidly growing problem worldwide. A family of chemical compounds, PFAS, known as “forever chemicals”, is of particular concern due to their extreme persistence under very different environmental conditions. Due to the persistence and ubiquity of these compounds, a recent study found that 98% of people tested had detectable levels of PFAS in their bloodstream. Now, researchers have devised a new material that could effectively and freely filter PFAS from water.
The material, which is based on natural silk and cellulose, can remove a wide range of these persistent chemicals, as well as heavy metals. In addition, their antimicrobial properties can help prevent a microbial layer from forming on the filters and hindering their work.
This promising breakthrough is the work of a team consisting of, among others, Yilin Zhang and Benedetto Marelli, from the Massachusetts Institute of Technology (MIT) in the United States.
Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are present in a wide range of products, such as cosmetics, food packaging, waterproof clothing, firefighting foam, and non-stick coatings for cookware. A recent study identified 57,000 places polluted by these chemicals in the United States alone.
The pollution of PFAS and similar compounds is a very serious problem, and current solutions can only partially solve it. Effective methods are very expensive, and cheap ones are very ineffective.
The new, efficient and cheap material has its special characteristics related to the integration of cellulose into the silk-based fibers and to adjustments that affect the electrical charge of the cellulose. The resulting membrane is thin and filters these substances with great efficiency.
By integrating cellulose into silk-based fibers that make up a thin membrane, and then adjusting the cellulose’s electrical charge, the researchers produced a material that proved highly effective at removing pollutants in laboratory tests. An example of the filter is shown in the image. (Image: research team/MIT. CC BY-NC-ND 3.0)
In addition, the electrical charge of cellulose has antimicrobial effects. The latter is a significant advantage, since one of the main causes of failure in filtration membranes is the formation of a layer by bacteria and fungi that obstructs flow through the filter. The antimicrobial properties of this material should greatly reduce that problem of microbial layer formation on the filter.
The new type of material is cheaper than the most effective materials currently used to remove metal ions and PFAS, but just as effective and even more effective than some. In the most extreme cases, the new type of material exceeds by orders of magnitude the capacity of some standard materials currently used to remove polluting agents from water. Ordinary activated carbon and granular activated carbon are two of those traditional materials that have greatly surpassed the new one.
Zhang, Marelli and their colleagues plan to continue working to improve the new material.
Their findings so far in their field of research and development were recently published in the academic journal ACS Nano, under the title “Directed assembly of protein-polysaccharide nanofibrins to form membranes for emerging contamination remediation.” (Source: NYT of Amazings)
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