Deciphering Effects of Surface Charge on Particle Removal by TiO2 Polyacrylonitrile Nanofibers

ABSTRACT

Over the recent years, the continued increase in the number of particles in air has become a public concern. This problem can be addressed by using nanofibers to filter fine particles. However, nanofibers possess complex characteristics. As such, the effects of surface charge require further studies. In this study, the surface voltages of nanofibers were analyzed with an electrometer after these fibers were charged through corona discharge to investigate the mechanism of filtration. Results indicated that the surface voltage of 2.0% TiO₂ polyacrylonitrile fibers (TPFs) can reach up to 0.97 kV and then decrease to 0.60 kV after 96 h. Particles were optimally removed by charged polyacrylonitrile fibers (PFs) and TPFs. Particle penetration decreased by 71% of TPF and 36% of PF. Scanning Electron Microscopy and Nitrogen adsorption/desorption isotherms revealed that increasing the surface area and roughness of these materials are more favorable for charge maintenance to promote particle removal. Our research could provide an in-depth understanding of the effects of surface charge on particle removal and show how systems can be optimized for further applications.