Toward understanding the evolution of incense particles on nanofiber filter media: Its influence on PM2.5 removal efficiency and pressure drop

摘要

Nanofiber filter media can potentially reduce exposure to PM2.5 in indoor environments because of the filters' high particle-removal efficiency. To facilitate such filter use, this study conducted a series of experiments to understand the evolution of wetting liquid aerosols, taking incense particles as an example, on nanofiber filter media and the influence of this evolution on PM2.5 removal efficiency and pressure drop. Scanning electron microscope images were also taken to observe the nanoscale interactions between incense particles and the nanofiber network. The results show that the PM2.5 removal efficiency at first decreased as the loading mass increased, because interactions between the particles and the nanofiber network enlarged the pores. The evolution of pressure drop may consist of two stages, i.e., a first stage with a linear relationship, and a second stage with a steep increase in pressure drop with the loading mass. When the pore size became small enough, in addition to inertial impaction and Brownian diffusion, the capture mechanism of interception also became significant. Consequently, the second stage, with a steep increase, tended to occur. Finally, methods for establishing empirical equations for PM2.5 removal efficiency and pressure drop as a function of loading mass were proposed.