AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Aerosol Emission Monitoring in the Production of Silicon Carbide Nanoparticles by Induction Plasma Synthesis
DREW THOMPSON, Jing Wang, Jelena Buha, Christian Jaeggi, Marc Leparoux, David Pui, University of Minnesota
Abstract Number: 555 Working Group: Health Related Aerosols
Abstract With the proliferation of products incorporating nanomaterials comes growing concern about occupational health and safety at workplaces where nanomaterials are produced or used. Key to evaluating the potential health risks posed by nanomaterials is the nature of inhalation exposure to airborne engineered nanoparticles. This is not only needed for establishing safer nanomaterial work practices, toxicology studies also require doses relevant to actual workplace exposures. In this study aerosol emissions were monitored at a research laboratory during the production of silicon carbide (SiC) nanoparticles by inductively coupled plasma (ICP) synthesis.
The use of direct-reading particle instruments was found to be an effective means by which to identify emission events and to assess the efficacy of the engineering controls and best practices guidelines in the production of nanoparticles by ICP synthesis. No particles were released during the synthesis of SiC nanoparticles due to the reactor being operated in a closed system under slight vacuum. However, aerosol emissions were identified in other related production tasks. A release of submicrometer particles was detected when a nanoparticle collection filter was disconnected from the reactor system. The use of compressed air when cleaning nanoparticle contaminated equipment was also investigated. When compressed air was used for cleaning in moderately closed ventilated systems, like the interior of the reactor, no particles were emitted. When compressed air was used for cleaning in open spaces, such as the cleaning of the nanoparticle collection filters in a ventilated walk-in enclosure, emissions of submicrometer particles were identified and particle number concentrations exceeded 250,000 cm$^(-3). Particle emissions in this facility were found to be largely submicrometer and exhibited a mode size of approximately 170 nm. Observation of filter samples under scanning electron microscope confirmed that the particles released were agglomerates of SiC nanoparticles.