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Electrospinning has advanced from a lab technique to an industrial method, enabling modern filters that are high-performing, sustainable, recyclable, and non-toxic. This study produced recycled PA6 nanofibers using green solvents and incorporated non-toxic CuO nanoparticles via industrial free-surface electrospinning. Polymer solutions with concentrations of 12.5, 15.0 and 17.5 (w/v)% were electrospun directly onto recyclable polypropylene spunbond/meltblown nonwoven substrates to produce nanofibers with average fiber sizes of 80–250 nm. Electrospinning parameter optimization revealed that the 12.5 wt.% PA6 solution and the 2–3 mm·s−1 winding speed had the optimal performance, attaining 98.06% filtering efficiency and a 142 Pa pressure drop. The addition of 5 wt.% CuO nanoparticles increased the membrane density and reduced the pressure drop to 162 Pa, thereby improving the filtration efficiency to 98.23%. Bacterial and viral filtration studies have demonstrated pathogen retention above 99%. Moreover, antibacterial and antiviral testing has demonstrated that membranes trap and inactivate microorganisms, resulting in a 2.0 log (≈approximately 99%) reduction in viral titer. This study shows that recycled PA6 can be converted into high-performance membranes using green, industrial electrospinning, introducing innovations such as non-toxic CuO functionalization and ultra-fine fibers on recyclable substrates, yielding sustainable filters with strong antimicrobial and filtration performance, which are suitable for personal protective equipment and medical filtration.
Žižková et al. (Mon,) studied this question.