Antibacterial filter media from recycled polyethylene terephthalate and reclaimed facemasks

This study presents a method for the development of high-performance filter media with antibacterial properties from the nanofibers of recycled polyethylene terephthalate (PET), electrospun on used facemasks and sets the stage for generating high-performance filter media from recycled feedstocks with potential applications in personal protective equipment. The electrospinning solutions of PET contain 10 to 25 wt% of PET dissolved in a solvent mixture of hexafluoroisopropanol and dichloromethane. The electrospun nanofibers obtained from 10 wt% PET solution demonstrate the best performance in filtering airborne nanoparticles with a filtration efficiency of 87 ± 2.9 % and a quality factor of 1.31 per 2.54 cm of water pressure drop across the media. The study also evaluates the influence of benzalkonium chloride (BAC) salt initially dissolved in PET solution at a concentration of 10–50 wt% with respect to the PET content on nanofiber diameter and filtration efficiency. The presence of BAC leads to fiber diameter reduction, narrowing of fiber diameter distribution, and production of bead-free, smooth fibers. The filter media produced with BAC show filtration efficiency of 98 ± 0.8 % and a quality factor of 1.77 per 2.54 cm of water pressure drop, that exceed the filtration performance of a commercial N95 mask. The study establishes the antibacterial attributes of BAC, e.g., nanofibers containing BAC inhibit the growth of the gram-negative bacteria, Pseudomonas aeruginosa and the gram-positive bacteria, Staphylococcus aureus. The nanofiber mat, with 20 wt% or greater content of BAC, releases enough BAC in the aqueous media to inhibit the growth of both S. aureus and P. aeruginosa.