Addressing the ever-pressing issue of water contamination, researchers at MIT have introduced a new player in the game of water purification - a filtration material that boasts the ability to rid water of tenacious PFAS chemicals and heavy metals. Described in a paper published in the journal ACS Nano, this innovation could be the nature-inspired answer that's been sought after, especially considering that nearly the entire American population, as per the U.S. Centers for Disease Control, carries detectable levels of PFAS in their bloodstreams.
MIT's promising filtration material, deriving from a blend of natural silk and cellulose, not only tackles a broad spectrum of substances but also harbors antimicrobial qualities that prevent the filters from becoming clogged over time, Benedetto Marelli, the professor of civil and environmental engineering and one of the minds behind the study, his team initially developed the silk-based technology aimed at thwarting the issue of counterfeit seeds which ironically led them to this water purification breakthrough. A heightened focus on PFAS, pervasive in everything from cosmetics to cookware, has illuminated the contamination of roughly 57,000 U.S. sites leaving the nation with a hefty $1.5 billion annual remediation bill in order to meet the EPA's stringent new drinking water standards.
The aberrant endurance of PFAS compounds, which grants them the moniker "forever chemicals," presents a formidable challenge in terms of removal from water sources. However, the MIT researchers' method could change the current narrative with its proficiency in filtering out such contaminants, a process that was not initially successful with silk nanofibrils alone, prompting the addition of cellulose to the mix. "Contamination by PFAS and similar compounds 'is actually a very big deal, and current solutions may only partially resolve this problem very efficiently or economically,'" Yilin Zhang, a postdoctoral associate at MIT and a co-author of the study, indicated in his interview with MIT News.
The collaborative effort led to a hybrid material whose innovativeness lies in the self-assembly technique employed; silk fibroin protein, in a water suspension, is templated into nanofibrils by depositing cellulose nanocrystals, which act as "seeds", this strategic merger not only refined the structural integrity of the material but also enhanced its filtration capacity, MIT News revealed that laboratory tests showed high efficacy in removing contaminants with the resultant silk-cellulose membrane, which is a mere 500nm thick, the material not only showcases impressive filtration capabilities but is also flexible as evidenced in the prototype images.
