Development of Bifunctional Electrospun Filters Incorporating Surfactants for Enhanced Particulate Matter Filtration and Antimicrobial Activity

Abstract

Ultrafine particulate matter and airborne microorganisms present in the atmosphere significantly affect human health, leading to serious respiratory diseases. Among these particulates are bioaerosols, which include viruses, bacteria, and fungi. When inhaled, these microorganisms can cause diseases, such as influenza, tuberculosis, and COVID-19. Therefore, the development of bifunctional membranes that can simultaneously filter particulate matter (PM) and inhibit microorganism growth is essential. Electrospun filters, known for their high surface area, are effective in capturing these airborne particles. This study presents a novel approach by incorporating various surfactants into electrospun filters made from 8% polyacrylonitrile (PAN). The surfactants used include cetyltrimethylammonium bromide (CTAB), widely cited in the literature for bactericidal filtering applications, as well as sodium dodecyl sulfate (SDS) and cetylpyridinium chloride (CPC), which are rarely used in electrospun filters for this purpose. The addition of surfactants enhanced the filter performance, capturing particles smaller than 250 nm with over 99% efficiency for particles between 6.38 and 242 nm. The pressure drop across the filters ranged from 111.4 ± 1.2 to 204.4 ± 1.1 Pa. Moreover, the incorporation of surfactants not only improved hydrophobic and hydrophilic properties—where hydrophobic nanofibers performed better for filtration—but also significantly increased antimicrobial activity against Staphylococcus aureus (97.25 ± 0.95%) and Escherichia coli (94.52 ± 2.37%). These filters not only capture particles but also inactivate pathogens, contributing to a healthier environment. Filters with biocidal properties are particularly useful in hospitals, laboratories, and other settings where air sterility is critical.