Filtration of Nanosized Particle Aerosols by Electret Fibrous Filters

摘要

Results of studying the filtration efficiency of various nanoaerosols in an air-cleaning system in which particles are charged in the integrated corona discharge unit and polymer fibers with electret properties serve as the filtration material are presented. The total filtration efficiency for titanium oxide (TiO_x), diethylhexylsebacate (DEHS), and bovine serum albumin (BSA) aerosols and anti-mosquito smoke (AMS) is 99.9, 99.3, 98.6, and 98.7%, respectively. A significant (5–10%) drop in the filtration efficiency has been observed for DEHS and BSA aerosols and AMS in a particle size range of less than 80 nm. It has been demonstrated that the filtration efficiency can be substantially increased by activating the electrostatic particle-capture mechanism through the charging of particles in the corona discharge unit. In connection with this, the electrostatic mechanism is the dominant one for particles larger than 80 nm, while its contribution decreases in the particle size range of less than 80 nm with a decrease in particle size and a simultaneous increase in the contribution of the capture mechanism due to diffusion. It has also been found that the increase in the filter solidity by a factor of higher than 1.5 has a negligible effect on the filtration efficiency, thus making it reasonable to utilize low-solidity electret filters whose quality factor reaches the maximal values.