Toward understanding the interaction between wetting liquid aerosols and metal organic framework-embedded nanofiber air filters

Incorporating metal-organic frameworks (MOFs) is a proven strategy to enhance the filtration efficiencies of nanofiber-based air filters created through electrospinning. However, the impact of particle loading on the MOF-embedded nanofiber filters is unclear, especially for wetting liquid aerosols, a common type of indoor airborne particle. Therefore, this study undertook a comprehensive set of experiments to explore the interaction between wetting liquid aerosols and MOF-embedded nanofiber air filters, utilizing incense particles and ZIF-67/PAN filters (denoted as MOF filters) as an example. PAN/Co(Ac) 2 filters, the precursor filters without MOFs embedded, (denoted as precursor filters) were also tested for comparison. The results indicate a decline in filtration efficiency as the mass of incense particles loaded onto the filters increased for both filter types, because the incense particles interacted with the nanofiber network and enlarged the pore sizes. Furthermore, at a given incense particle loading mass, the MOF filters demonstrated higher filtration efficiency compared to the precursor filters, in part because the filter with ZIF-67 crystals embedded had fewer open pores for the particles to penetrate. In the final stage of the loading process, the particle filtration efficiency did not change significantly, with the MOF filters’ filtration performance gradually aligning with the precursor filters. Moreover, the pressure drop increased with incense particle loading mass, and the embedded ZIF-67 crystals also increased the pressure drop. These findings highlight the potential issue of decreased filtration efficiency and increased pressure drop due to the loading of wetting liquid aerosols for practical applications of MOF-embedded nanofiber air filters.