Transmission electron microscopical and aerosol dynamical characterization of soot aerosols

Wentzel, Michael; Gorzawski, Hauke; Naumann, K.‐H.; Saathoff, H.; Weinbruch, Stephan

doi:10.1016/s0021-8502(03)00360-4

Cited by 375 publications

(279 citation statements)

References 38 publications

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“…The fractal dimension of 1.88 for particles before scrubber indicates slightly more bulky forms than fresh soot, which would rather have a fratal dimension of 1.7 (Wentzel et al 2003). This suggests that material (probably due to fuel composition: sulfur content of 0.5% w/w to 0.75% w/w) had already condensed on particles before the scrubber, causing some change in morphology from fresh to partly compacted soot forms.…”

Section: Discussionmentioning

confidence: 99%

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Micro- and Nanostructural Characteristics of Particles Before and After an Exhaust Gas Recirculation System Scrubber

Lieke

Rosenørn

Pedersen³

et al. 2013

Aerosol Science and Technology

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This work provides insight into the morphology and mixing state of submicron particles in diesel exhaust from a ship engine with an exhaust gas recirculation scrubber. Particles from this low-speed ship engine on test bed were collected using a microinertial impactor with transmission electron microscopy (TEM) grids on two stages. Micro-and nanostructural characteristics of single particles were studied by TEM. Image analysis was carried out on overview and high-resolution images, revealing influence of the exhaust gas treatment (scrubber) on the particle morphology and mixing state. Soot agglomerates were found to be collapsed after scrubber, reflected by their change in fractal dimension (D f ) from 1.88 to 2.13. Soot was predominantly found internally mixed with other components, with a higher degree of internal mixing observed after scrubber. Soot nanostructural characteristics on the near atomic scale such as layer distance, lamella length, and tortuosity were not observed to be influenced by the scrubber. We also found that particles in the size range between 30 and 50 nm, which were abundant in the exhaust before and after scrubber, were not graphitic soot. Furthermore, we found indica-

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Section: Discussionmentioning

confidence: 99%

“…The complex geometry of these agglomerates can be described by the fractal dimension D f (Samson et al 1987;Brasil et al 1999;Wentzel et al 2003;Gwaze et al 2006). Diesel soot is described to have a fractal dimension around 1.7, referring to large, open, widely branched structures.…”

Section: Introductionmentioning

confidence: 99%

Micro- and Nanostructural Characteristics of Particles Before and After an Exhaust Gas Recirculation System Scrubber

Lieke

Rosenørn

Pedersen³

et al. 2013

Aerosol Science and Technology

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“…TEM has been widely used for studying this material with specific properties (Table 1). Although there is extensive mention of soot in TEM aerosol studies (Palot as et al 1996;Ishiguro et al 1997;Buseck and Schwartz 2003;Li et al 2003;Wentzel et al 2003;Patel et al 2012), we believe it is appropriate to draw a clear distinction based on physical features rather than origin or optical properties for at least this one important type of aerosol particle. To provide greater specificity, reduce ambiguity, and to distinguish "soot" from BC, EC, and other terms that are commonly used as synonyms, we propose the term "ns-soot" for particles with grape-like (aciniform; Medalia and Rivin 1982) morphologies that consist of nanospheres that possess distinct internal structures of concentrically wrapped, graphene-like layers of carbon.…”

Section: Ns-sootmentioning

confidence: 96%

Ns-Soot: A Material-Based Term for Strongly Light-Absorbing Carbonaceous Particles

Buseck

Adachi

Gelencsér

et al. 2014

Aerosol Science and Technology

102

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The climate-change and environmental literature, including that on aerosols, is replete with mention of black carbon (BC) and soot. The terms are used interchangeably in much of the literature, although BC and soot commonly have operational and source-based definitions, respectively, and reliable reference samples and aerosol standards do not exist for either one. The uncertainty about their exact chemical nature and properties can be decreased by materials-based measurement techniques and terminology. Here, we discuss ambiguities in common uses of BC and soot and propose the term ns-soot, where "ns" refers to carbon nanospheres, for a characteristic constituent of BC and soot. Based on its composition, morphology, and structure, we define ns-soot as particles that consist of nanospheres, typically with diameters <100 nm, that possess distinct structures of concentrically wrapped, graphene-like layers of carbon and with grape-like (aciniform) morphologies. We additionally propose that, because of their importance for climate modeling and health issues, distinctions are made among bare, coated, and embedded ns-soot particles.

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“…In fact, soot particles are one of the few particle types that can be readily recognized under the scanning or transmission electron microscope by their special morphology (Oberlin, 1989). Primary soot particles, 10-50 nm spherules, do not exist by themselves in ambient air-instead they cluster together immediately after their formation in a flame to form aggregates, which are their most stable form (Wentzel et al, 2003). In fresh smoke, these clusters tend to form open structures, which are then transformed by aging processes, including the uptake of water, into more closely packed particle types (Colbeck et al, 1990;Weingartner et al, 1997;Ruellan et al, 1999;Abel et al, 2003;Onischuk et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

“…High resolution transmission electron microscopy (HRTEM) revealed that the internal structure of combustion soot spherules depends strongly on the chemical and thermal environment under which they are formed and on the time available for annealing (Buseck et al, 1987;Su et al, 2004). Very rapidly formed soot particles are nearly amorphous, with only some signatures of short-range order (Pósfai et al, 1999;Grieco et al, 2000;Ferry et al, 2002;Wentzel et al, 2003), with fullerenic structures developing at slightly longer residence times in the combustion region. At longer annealing times (seconds to minutes) or higher temperatures, more highly ordered carbon structures develop.…”

Section: Introductionmentioning

confidence: 99%

Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols

Andreae

Gelencsér²

2006

Atmos. Chem. Phys.

1,768

1,033

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Abstract. Although the definition and measurement techniques for atmospheric "black carbon" ("BC") or "elemental carbon'' ("EC") have long been subjects of scientific controversy, the recent discovery of light-absorbing carbon that is not black ("brown carbon, Cbrown") makes it imperative to reassess and redefine the components that make up light-absorbing carbonaceous matter (LAC) in the atmosphere. Evidence for the atmospheric presence of Cbrown comes from (1) spectral aerosol light absorption measurements near specific combustion sources, (2) observations of spectral properties of water extracts of continental aerosol, (3) laboratory studies indicating the formation of light-absorbing organic matter in the atmosphere, and (4) indirectly from the chemical analogy of aerosol species to colored natural humic substances. We show that brown carbon may severely bias measurements of "BC" and "EC" over vast parts of the troposphere, especially those strongly polluted by biomass burning, where the mass concentration of Cbrown is high relative to that of soot carbon. Chemical measurements to determine "EC" are biased by the refractory nature of Cbrown as well as by complex matrix interferences. Optical measurements of "BC" suffer from a number of problems: (1) many of the presently used instruments introduce a substantial bias into the determination of aerosol light absorption, (2) there is no unique conversion factor between light absorption and "EC" or "BC" concentration in ambient aerosols, and (3) the difference in spectral properties between the different types of LAC, as well as the chemical complexity of Cbrown, lead to several conceptual as well as practical complications. We also suggest that due to the sharply increasing absorption of Cbrown towards the UV, single-wavelength light absorption measurements may not be adequate for the assessment of absorption of solar radiation in the troposphere. We discuss the possible consequences of these effects for our understanding of tropospheric processes, including their influence on UV-irradiance, atmospheric photochemistry and radiative transfer in clouds.

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Transmission electron microscopical and aerosol dynamical characterization of soot aerosols

Cited by 375 publications

References 38 publications

Micro- and Nanostructural Characteristics of Particles Before and After an Exhaust Gas Recirculation System Scrubber

Micro- and Nanostructural Characteristics of Particles Before and After an Exhaust Gas Recirculation System Scrubber

Ns-Soot: A Material-Based Term for Strongly Light-Absorbing Carbonaceous Particles

Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols

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