Development and evaluation of antibacterial nanofiber membranes via coaxial electrospinning for enhanced air filtration performance

Abstract

As industrialization intensifies and the population soars, the challenge of air pollution escalates into a pressing concern. Electrospun nanofiber membranes, owing to their distinctive attributes including high specific surface area, porosity, and uniform pore size distribution, have emerged as promising candidates for air filtration. In this study, we successfully prepared ZnO@polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) antibacterial nanofiber membranes through a combined solvothermal and coaxial electrospinning approach. The structure and performance of these nanofiber membranes were systematically modulated by adjusting the shell feeding rate and zinc acetate dihydrate (Zn(Ac)₂·2H₂O) concentration. Specifically, an increase in the shell feeding rate led to a decrease in fiber diameter, accompanied by the proliferation of nano-beads, thereby contributing to a reduction in membrane pore size. Consequently, a heightened shell feeding rate correlated positively with both filtration efficiency and pressure drop. Furthermore, the incompletely reacted Zn(Ac)₂·2H₂O enhanced the conductivity of the spinning solution, facilitating a decrease in pore size and enhancing air filtration performance. In summary, when the shell feeding rate was 0.60 mL h⁻¹ and Zn(Ac)₂·2H₂O concentration was 1.5 wt%, the obtained ZnO@PVDF-HFP nanofiber membrane exhibited superior air filtration performance, with high filtration efficiency of 99.91 %, low pressure drop of 80.70 Pa and noteworthy quality factor of 0.08781 Pa^-1. Notably, these membranes sustained their high filtration efficiency and low pressure drop even after 40 min of continuous testing, underscoring their exceptional stability. In addition, the obtained nanofiber membrane exhibited robust antibacterial activity against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), demonstrating their multifaceted potential. Our work not only simplifies the fabrication process of electrospun nanofiber membranes with superior air filtration and antibacterial properties but also highlights their potential as innovative alternatives to conventional air filter materials, poised for diverse practical applications.