A Study on the comparison of MWCNT mass concentration among different measurement techniques

Abstract

Carbon nanotubes (CNTs), which were first synthesized in 1991, have significantly higher electroconductivity, thermoconductivity, and strength than other substances, and, as such, have been used in various applications. CNTs were also found to consist of needles which, like asbestos, are toxic and harmful to humans. Researchers work routinely, however, on CNTs without any protective clothing. Studies of the inhalation toxicity involving real-time measurements were conducted at actual work places. Unfortunately, it was impossible to measure only the CNTs and unstable concentrations were frequently encountered during long periods of spraying. In this study, a constant concentration was maintained during long spraying and real-time measurements of the MWCNTs, which were sprayed in a similar manner to that of asbestos by reducing the agglomeration effect. Moreover, measurements were performed for various concentrations of the MWCNTs, which were by different spraying methods. The particle size distribution and the amount of black carbon (BC) of the MWCNT aerosol were measured using the scanning mobility particle sizer (SMPS) and an aethalometer, respectively. The results were also compared after measuring the elemental carbon (EC) and organic carbon (OC) with the NIOSH 5040 method that is typically used to determine the carbon of the particles exhausted from diesel engines.