Heterogeneous Freezing of Carbon Nanotubes: A Model System for Pore Condensation and Freezing in the Atmosphere

Alstadt, Valerie J.; Dawson, Joseph Nelson; Losey, Delanie J.; Sihvonen, Sarah K.; Freedman, Miriam Arak

doi:10.1021/acs.jpca.7b06359

Cited by 11 publications

(30 citation statements)

References 49 publications

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“…However, why the earlier work indicated that BC is an effective ice‐nucleating material (Murray et al, 2012; Phillips et al, 2008, 2013) is unclear, and it may be that combustion of some fuels under some conditions can produce BC that is strongly ice active. As mentioned above, elemental carbon in some forms has been shown to nucleate ice effectively (Alstadt et al, 2017; Bai et al, 2019; Whale, Rosillo‐Lopez, et al, 2015), but it remains unclear if this highly ice‐active form of BC is atmospherically important. Nevertheless, we have shown that BC generated on Bonfire Night from a range of fuels and combustion conditions has a very low ice‐nucleating activity and does not significantly enhance the INP population.…”

Section: Resultsmentioning

confidence: 99%

“…There is evidence that BC nucleates ice when immersed in (or at least in the presence of) supercooled droplets (DeMott, 1990; Diehl & Mitra, 1998; Fornea et al, 2009; Gorbunov et al, 2001; Kireeva et al, 2009; Popovicheva et al, 2008; Wright et al, 2013). In addition, carbon‐based materials including graphene oxides and carbon nanotubes nucleate ice, which shows that carbon‐rich materials have the potential to nucleate ice (Alstadt et al, 2017; Bai et al, 2019; Whale, Rosillo‐Lopez, et al, 2015). Murray et al (2012) parameterized data from DeMott (1990), who used soot from an oxygen‐deficient acetylene burner, and Diehl and Mitra (1998), who used a kerosene burner, by calculating the ice‐active site surface density, n s ( T ), of BC, and concluded that BC may be a very important INP type globally.…”

Section: Introductionmentioning

confidence: 99%

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A Major Combustion Aerosol Event Had a Negligible Impact on the Atmospheric Ice‐Nucleating Particle Population

et al. 2020

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Clouds containing supercooled water are important for both climate and weather, but our knowledge of which aerosol particle types nucleate ice in these clouds is far from complete. Combustion aerosols have strong anthropogenic sources, and if these aerosol types were to nucleate ice in clouds, they might exert a climate forcing. Here, we quantified the atmospheric ice-nucleating particle (INP) concentrations during the United Kingdom's annual Bonfire Night celebrations, which are characterized by large amounts of combustion aerosol from bonfires and fireworks. We used three immersion mode techniques covering more than 6 orders of magnitude in INP concentration over the temperature range from −10°C to homogeneous freezing. We found no observable systematic change in the INP concentration on three separate nights, despite more than a factor of 10 increase in aerosol number concentrations, up to a factor of 10 increase in PM 10 concentration, and more than a factor of 100 increase in black carbon (BC) mass concentration relative to pre-event levels. This implies that BC and other combustion aerosol such as ash did not compete with the INPs present in the background air. Furthermore, the upper limit of the ice-active site surface density, n s (T), of BC generated in these events was shown to be consistent with several other recent laboratory studies, showing a very low ice-nucleating activity of BC. We conclude that combustion aerosol particles similar to those emitted on Bonfire Night are at most of secondary importance for the INP population relevant for mixed-phase clouds in typical midlatitude terrestrial locations. Plain Language Summary Liquid water droplets found in clouds can cool to well below 0°C while remaining in the liquid phase (this is known as supercooling). These supercooled droplets can remain liquid down to below around −33°C without freezing, unless there is a certain type of aerosol particle present: an ice-nucleating particle (INP). Hence, INPs have the potential to drastically change the properties and lifetime of clouds, but the sources of INP in the atmosphere are poorly defined. In this study we measured the INP concentration before, during, and after a major combustion aerosol event in the United Kingdom, Bonfire Night. This celebration is characterized by bonfires (primarily made of waste wood, but also containing garden and household waste) and fireworks. We found that aerosol particles emitted during the celebration are not as effective at nucleating ice as aerosol particle already present in the atmosphere. We conclude that aerosol particles emitted from combustion processes such as those observed on Bonfire Night are not an important source of INPs.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Major Combustion Aerosol Event Had a Negligible Impact on the Atmospheric Ice‐Nucleating Particle Population

et al. 2020

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“…Immersion freezing data were taken using an environmental chamber described in detail in Alstadt et al 60 Briefly, 2 μL droplets of 0.02 wt. % of iron oxide powder in UHPLC-MS water (Fisher Scientific) were pipetted onto silanized slides (Hampton Research).…”

Section: Experimental Methodsmentioning

confidence: 99%

Ice nucleation activity of iron oxides via immersion freezing and an examination of the high ice nucleation activity of FeO

Chong

Marak

et al. 2021

Phys. Chem. Chem. Phys.

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“…Additionally, BET analysis with nitrogen gas was performed on the ASAP 2020 Automated Surface Area and Porosimetry System to determine the surface area of each sample. 44 Immersion freezing data were taken using an environmental chamber described in detail by Alstadt et al 45 Briefly, 2 μL droplets (∼7 mm diameter) of 0.02 wt % alumina in ultrapure water (Millipore Q, 18.2 Ω•cm 2 ) were pipetted onto siliconized slides (Hampton Research). From the average diameter (50 μm) observed with SEM, approximately 100 alumina particles are within each drop.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

The Effect of Crystallinity and Crystal Structure on the Immersion Freezing of Alumina

et al. 2019

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Determining the factors that constitute an efficient ice nucleus is an ongoing area of research in the atmospheric community. In particular, surface characteristics such as functional groups and surface defects impact the ice nucleation efficiency. Crystal structure has been proposed to be a possible factor that can dictate ice nucleation activity through the templating of water molecules on the surface of the aerosol particle. If the crystal structure of the surface matches that of the crystal structure of ice, it has been shown to increase ice nucleation activity. In this study, alumina was chosen as a model system because crystal structure and crystallinity can be tuned, and the effect on immersion freezing was explored. The nine alumina samples include polymorphs of AlOOH, Al(OH) 3 , and Al 2 O 3 , which have a range of crystal structures and crystallinities. The samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and Brunauer−Emmett−Teller (BET) analysis. From the immersion freezing experiments, corundum [α-Al 2 O 3 ] was shown to have the highest ice nucleation activity likely because of its high lattice match and high degree of crystallinity. Crystal structure alone did not show a strong correlation with ice nucleation activity, but a combination of a hexagonal crystal structure and a highly crystalline surface was seen to nucleate ice at warmer temperatures than the other alumina samples. This study provides experimental results in the study of ice nucleation of a range of alumina samples, which have possible implications for alumina-based mineral dust particles. Our findings suggest that crystallinity and crystal structure are important to consider when evaluating the ice nucleation efficiency of aerosol particles in laboratory and modeling studies.

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Heterogeneous Freezing of Carbon Nanotubes: A Model System for Pore Condensation and Freezing in the Atmosphere

Cited by 11 publications

References 49 publications

A Major Combustion Aerosol Event Had a Negligible Impact on the Atmospheric Ice‐Nucleating Particle Population

A Major Combustion Aerosol Event Had a Negligible Impact on the Atmospheric Ice‐Nucleating Particle Population

Ice nucleation activity of iron oxides via immersion freezing and an examination of the high ice nucleation activity of FeO

The Effect of Crystallinity and Crystal Structure on the Immersion Freezing of Alumina

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