A reusable nanofibrous air filter with anti-wetting microbead coating

Abstract

Filtration technologies for fine dust particles have garnered attention as public awareness of air pollution has increased. In this study, we report a microbead-coated polyacrylonitrile nanofibrous membranes (MB-NFMs) filter, which is a reusable PAN nanofiber-based air filter with high dust-filtration efficiency. The MB-NFMs filter comprises a dual-layer structure composed of hydrophilic PAN nanofibers coated with hydrophobic microbeads to produce high filtration efficiency and water droplet cleaning ability. This membrane has water contact angles of approximately 144°, which allows water droplets to roll off its surface and carry captured dust particles with them. Furthermore, we discovered that the MB-NFMs filter has sufficient wetting resistance to maintain its hydrophobicity under raindrop impacts. The MB-NFMs filter had a removal efficiency of over 99.8% for PM2.5. Repetitive dust-filtration and water droplet-cleaning cycles were performed to evaluate the MB-NFMs filter's ability to clean water droplets. The filtration efficiency was higher than 99.8% throughout the tests, and the pressure drop was recovered by 99% after each cleaning cycle. The fabricated MB-NFMs filter is a viable solution for highly efficient and reusable dust-particle filtration. The MB-NFMs filter does not require periodic maintenance due to its water droplet cleaning ability, providing an economic advantage over conventional air filters.