Carbon Nanotube and Fullerene Emissions from Spark-Ignited Engines

Lagally, Christie D.; Reynolds, Conor C. O.; Grieshop, A. P.; Kandlikar, Milind; Rogak, Steven N.

doi:10.1080/02786826.2011.617399

Cited by 31 publications

(19 citation statements)

References 36 publications

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“…It should be noted that the suspended SWCNTs tend to form agglomerates due to their geometry and van der Waals forces, as supported by the aerodynamic size distribution (Supporting Information Figure S1) and previous measurements of CNTs collected directly from engine exhaust 17 and other flame exhausts. 18 While a kinetic limitation to the oxidation of internal SWCNTs in the agglomerates of the current experiments may occur, it is also likely to occur in the atmosphere.…”

Section: ■ Introductionmentioning

confidence: 97%

“…9 However, it is recognized that inhalation of manufactured nanoparticles (MNPs) including CNTs in ambient air will be an important pathway for population exposure in the future, 16 as the MNPs are possibly emitted through the degradation of their end products or during their manufacture. They have also recently been found in diesel exhaust (MWCNTs) 17 and other flame exhausts. 18 Once emitted into the atmosphere, chemical modification of CNTs may occur through the oxidation by O 3 , OH, and NO 3 radicals and by the reaction with, or condensation of, pre-existing ambient organic species.…”

Section: ■ Introductionmentioning

confidence: 99%

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Chemical and Toxicological Evolution of Carbon Nanotubes During Atmospherically Relevant Aging Processes

Liggio

Breznan

et al. 2015

Environ. Sci. Technol.

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The toxicity of carbon nanotubes (CNTs) has received significant attention due to their usage in a wide range of commercial applications. While numerous studies exist on their impacts in water and soil ecosystems, there is a lack of information on the exposure to CNTs from the atmosphere. The transformation of CNTs in the atmosphere, resulting in their functionalization, may significantly alter their toxicity. In the current study, the chemical modification of single wall carbon nanotubes (SWCNTs) via ozone and OH radical oxidation is investigated through studies that simulate a range of expected tropospheric particulate matter (PM) lifetimes, in order to link their chemical evolution to toxicological changes. The results indicate that the oxidation favors carboxylic acid functionalization, but significantly less than other studies performed under nonatmospheric conditions. Despite evidence of functionalization, neither O 3 nor OH radical oxidation resulted in a change in redox activity (potentially giving rise to oxidative stress) or in cytotoxic end points. Conversely, both the redox activity and cytotoxicity of SWCNTs significantly decreased when exposed to ambient urban air, likely due to the adsorption of organic carbon vapors. These results suggest that the effect of gas−particle partitioning of organics in the atmosphere on the toxicity of SWCNTs should be investigated further.

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Section: ■ Introductionmentioning

confidence: 97%

Section: ■ Introductionmentioning

confidence: 99%

Chemical and Toxicological Evolution of Carbon Nanotubes During Atmospherically Relevant Aging Processes

Liggio

Breznan

et al. 2015

Environ. Sci. Technol.

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“…• C) low-velocity jet impinging on a TEM grid (slightly above ambient temperature) as described by Lagally et al (2012). For this flow configuration, the aerodynamic cut-off diameter (d 50 ) is approximately 300 nm; nearly all particles sampled are below this size but it is likely that impaction contributed to the large particle sizes observed by microscopy.…”

Section: Methodsmentioning

confidence: 99%

Mass, Mobility, Volatility, and Morphology of Soot Particles Generated by a McKenna and Inverted Burner

Ghazi

Tjong

Soewono

et al. 2013

Aerosol Science and Technology

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Particle mass, mobility, volatile mass fraction, effective density, mass concentration, mass-mobility exponent, and particle morphology were measured from soot generated from a premixed flame (McKenna burner) and an inverted diffusion flame over a range of equivalence ratios. It was found that the mass fraction of volatile material on the soot from the McKenna burner could be up to 0.83 at a high equivalence ratio, but there was no measurable volatile material on the soot from the inverted burner. The inverted burner can produce soot at different mass-mobility exponents, ranging from 2.23 to 2.54, over a range of global equivalence ratios of 0.53-0.67, while the mass-mobility exponent ranges from 2.19 to 2.99 for fresh soot and 2.19 to 2.81 for denuded soot for the McKenna burner at equivalence ratios of 2.0-3.75. Transmission electron microscopy analysis of inverted burner soot shows that a range of particle morphologies is present at a given global equivalence ratio, likely due to different local equivalence ratios and flame conditions in the diffusion flame. Primary particle diameter tends to increase with aggregate size, which could contribute to the mass-mobility exponent being well above 2.

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“…Previously, it was reported about the identification of fullerenes in an atmospheric carbon-containing aerosol [20,21]. Fullerene soot can get into the atmosphere as a result of combustion processes of natural gas [22], fuel (including aviation fuel) [23][24][25][26], coal [20] and biomass [27]. Earlier, it was reported that polycyclic aromatic hydrocarbons in the combustion process can turn into soot containing fullerenes [28].…”

Section: Resultsmentioning

confidence: 99%