Experimental study of filtration efficiency of nanoparticles below 20 nm at elevated temperatures

This paper reports the measurements of the single fiber efficiency for a screen mesh at elevated temperatures up to 500 K for silver nanoparticles in the size range from 3 to 20 nm. Thermal rebound of particles from a filter surface is predicted to occur at 500 K for 3 nm diameter particles based on a theory by Wang and Kasper [(1991). Filtration efficiency of nanometer-size aerosol particles. Journal of Aerosol Science, 22, 31-41]; however, rebound was not detected in our study. A small change in the single fiber efficiency with temperature was observed for a fixed mass flow as is predicted by classical filtration theory. The measured increase of 8 % ± 5 % for particles of size 3, 4, and 5 nm is less than the 19% predicted by classical filtration theory. Measurements of particle penetration at a temperature of about 600 K were not possible because of particle production within the filter/holder.