Dispersion and filtration of carbon nanotubes (CNTs) and measurement of nanoparticle agglomerates in diesel exhaust

Carbon nanotubes (CNTs) tend to form bundles due to their geometry and van der Walls forces, which usually complicates studies of the CNT properties. Dispersion plays a significant role in CNT studies and we summarize dispersion techniques to generate airborne CNTs from suspensions or powders. We describe in detail our technique of CNT aerosolization with controlled degree of agglomeration using an electrospray system. The results of animal inhalation studies using the electrosprayed CNTs are presented. We have performed filtration experiments for CNTs through a screen filter. A numerical model has been established to simulate the CNT filtration experiments. Both the modeling and experimental results show that the CNT penetration is less than the penetration for a sphere with the same mobility diameter, which is mainly due to the larger interception length of the CNTs. There is a need for instruments capable of fast and online measurement of gas-borne nanoparticle agglomerates. We developed an instrument Universal NanoParticle Analyzer (UNPA) and the measurement results for diesel exhaust particulates are presented. The results presented here are pertinent to non-spherical aerosol particles, and illustrate the effects of particle morphology on aerosol behaviors.

► A summary of the dispersion techniques for airborne carbon nanotubes (CNTs) is presented.
► CNT aerosolization by electrospray and the toxicity study with the CNTs are presented.
► Filtration of airborne CNTs is investigated both experimentally and numerically.
► Diesel exhaust particulates are measured with the Universal NanoParticle Analyzer.