A group from the Federal University of Espírito Santo (UFES) has developed face masks coated with cellulose nanofibers extracted from sugarcane bagasse, originally intended to filter out the virus that causes COVID-19. The bagasse is pretreated with sodium hydroxide (NaOH) to remove unwanted compounds, then with the enzyme cellulase, which breaks the cellulose down into smaller fibers. As a result, the nanofibers separate and become suspended in an enzyme solution. Finally, the nanofibers are sprayed onto the fabric mask. Masks produced using the method had an antimicrobial filtration efficiency of 99.8%, while masks made from the same material without the coating were less than the minimum requirement of 95%. “I never imagined the results would be so good,” says UFES chemical engineer Luciana Zortea, who points out that the protection matched the most effective current options, such as PFF2 and PFF3 masks. Breathability tests showed wide variation and will be redone. The UFES group intends to look into licensing possibilities to make production viable as soon as the lab tests are complete (Journal of Material Research and Technology, March).
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