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Microstructures and Nanostructures for Environmental Carbon Nanotubes and Nanoparticulate Soots
Department of Metallurgical and Materials Engineering, The University of Texas at El Paso, El Paso, TX 79968, USA
Received: 18 September 2008; Accepted: 5 December 2008 / Published: 31 December 2008
Abstract: This paper examines the microstructures and nanostructures for natural (mined) chrysotile asbestos nanotubes (Mg3 Si2O5 (OH)4) in comparison with commercial multiwall carbon nanotubes (MWCNTs), utilizing scanning and transmission electron microscopy (SEM and TEM). Black carbon (BC) and a variety of specific soot particulate (aggregate) microstructures and nanostructures are also examined comparatively by SEM and TEM. A range of MWCNTs collected in the environment (both indoor and outdoor) are also examined and shown to be similar to some commercial MWCNTs but to exhibit a diversity of microstructures and nanostructures, including aggregation with other multiconcentric fullerenic nanoparticles. MWCNTs formed in the environment nucleate from special hemispherical graphene “caps” and there is evidence for preferential or energetically favorable chiralities, tube growth, and closing. The multiconcentric graphene tubes (~5 to 50 nm diameter) differentiate themselves from multiconcentric fullerenic nanoparticles and especially turbostratic BC and carbonaceous soot nanospherules (~8 to 80 nm diameter) because the latter are composed of curved graphene fragments intermixed or intercalated with polycyclic aromatic hydrocarbon (PAH) isomers of varying molecular weights and mass concentrations; depending upon combustion conditions and sources. The functionalizing of these nanostructures and photoxidation and related photothermal phenomena, as these may influence the cytotoxicities of these nanoparticulate aggregates, will also be discussed in the context of nanostructures and nanostructure phenomena, and implications for respiratory health.
Keywords: Chrysotile asbestos nanotubes; multiwall carbon nanotubes; carbonaceous soot nanoparticulates; SEM and TEM characterization; health effects
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MDPI and ACS Style
Murr, L.E. Microstructures and Nanostructures for Environmental Carbon Nanotubes and Nanoparticulate Soots. Int. J. Environ. Res. Public Health 2008, 5, 321-336.
Murr LE. Microstructures and Nanostructures for Environmental Carbon Nanotubes and Nanoparticulate Soots. International Journal of Environmental Research and Public Health. 2008; 5(5):321-336.
Murr, L. E. 2008. "Microstructures and Nanostructures for Environmental Carbon Nanotubes and Nanoparticulate Soots." Int. J. Environ. Res. Public Health 5, no. 5: 321-336.