Chemical separation in a binary liquid aerosol by filtration using electrospun membranes

Abstract

Binary liquid aerosols were filtered using electrospun fiber membranes for the purpose of demonstrating the feasibility of changing aerosol composition through size selection. The impacts of filtration on the particle size distribution and the overall composition of the aerosols were studied and correlated to the filter properties. The binary liquid aerosols comprised di(2-ethylhexyl) sebacate and di(2-ethylhexyl) phthalate, with median mobility diameters between 200 nm and 300 nm. Droplet size-resolved measurements of aerosol composition, performed using a combination of cascade impactor and gas chromatography-mass spectrometry (GC–MS), revealed size-dependent compositional variation. Electrospun membranes of polyacrylonitrile with four different fiber diameters, ranging from 300 nm to 1 μm, were tested. The membranes with small fiber diameters were more likely to have significant impact on both the size and composition of the aerosols. Electrospun membranes consisting of 300 nm diameter fibers altered the median particle diameter by as much as 4%, and the overall composition of the aerosols by as much as 30%. Membranes with large fiber diameters, on the other hand, exhibited negligible effects on the aerosol systems with regard to both aerosol size and composition. Electrospun cellulose acetate membranes of different thicknesses were also tested on a binary aerosol system with the same components. Thicker filters resulted in greater decrease in mean particle size and greater change of aerosol composition, up to 16%. The changes in aerosol size distribution and composition upon filtration were correlated through the droplet size-dependence of the aerosol composition.