Exposure Assessment of Solid Carbon Materials Through Atmospheric Carbon Dioxide Solidification Process
EMI FUKUDA, Satsuki Takai, Taiki Nagaya, Yasuto Matsui, Graduate School of Engineering, Kyoto University
Abstract Number: 620
Working Group: Health-Related Aerosols
Abstract
Carbon Capture, Utilization and Storage (CCUS) is one of the most promising technology to address climate change and global warming. In particular, the process of converting CO2 into solid carbon nano materials such as carbon nanotubes (CNTs) and carbon nanofibers (CNFs) is regarded as a more effective method for stable storage and resource recovery compared to gaseous CO2. Therefore, it is considered a critical strategy for achieving a low-carbon society.
Some studies have suggested inhalation risks among workers in CNTs and CNFs manufacturing facilities. However, there is little data concerning occupational exposure assessment in CCUS laboratories or facilities. The purpose of this study is to quantify and assess the potential exposure of workers to solid carbon products generated in a research facility developing CO2 solidification technology. To assess exposure, particle number concentrations were measured using Dust Meter (Compliant with Japanese labor law), Fast Mobility Particle Sizer (FMPS) and Optical Particle Sizer (OPS) during the entire work process. In addition, personal exposure was evaluated during the operation using the personal air sampling method. Collected products, personal breathing zone samples, and area samples were analyzed by transmission electron microscopy (TEM).
As a result, all particle sizes showed high concentrations (number/m3) during the operation of the solidification stainless chamber. TEM observations of the filter collected by the low-pressure impactor showed that most of the solid carbon was CNFs, with a few CNTs. Concentrations of dust with large particle sizes were low in all environments and situations, and personal exposures were small for each worker.
In summary, our results showed that a few CNTs may be produced under certain conditions and the potential for worker exposure to CNF-like structures and their fine fragments in the process of solidifying atmospheric carbon dioxide.