Comparison of filtration performance and antibacterial properties of nanofibers containing natural (thyme) and synthetic (ZIF-8) compounds in face mask media: Evaluating the potential of natural compounds as substitutes for synthetic agents: Natural

This study introduces a comparative approach to integrating natural and synthetic antibacterial agents into electrospun nanofiber media for face masks, aiming to reduce health and environmental concerns associated with synthetic compounds. Polyacrylonitrile (PAN) nanofibers incorporating thyme extract (5, 20, 40, 60 wt%) and ZIF-8 (5, 7, 10, 15 wt%) were fabricated and evaluated. Structural analyses confirmed uniform bead-free nanofibers with average diameters ranging from 207.5 to 234.2 nm and membrane thicknesses around 150 µm. FTIR and XRD data verified successful incorporation and chemical bonding of additives within the PAN matrix. Performance testing demonstrated that thyme-based nanofibers (40 wt%) achieved a particle filtration efficiency (PFE) of 96.83% (0.3 µm), 100% bacterial filtration efficiency (BFE), and a pressure drop of 20.33 Pa. ZIF-8 nanofibers (7 wt%) achieved 96.58% PFE and 96.06% BFE with a pressure drop of 25 Pa. Time-kill assays showed superior antibacterial activity of thyme compared to ZIF-8 over a 4-h period. Compared to melt-blown media, nanofiber samples provided significantly higher filtration performance with acceptable breathability. The findings highlight that thyme-loaded nanofibers offer a biodegradable, non-toxic, and efficient alternative to synthetic agents such as ZIF-8. This work provides new insights into structure–property–performance relationships in functional nanofibers and suggests natural compounds as promising candidates for safer and more sustainable face mask technologies though further research on scalability, long-term stability, mechanical durability, biodegradability, and breathability is warranted.