Anomalous hygroscopic growth of fine particles of MgSO4 aerosols investigated by FTIR/ATR spectroscopy

Wang, Liangyu; Ding, Fei; Zhang, Yunhong; Zhao, Li; Hu, Yonggang

doi:10.1016/j.saa.2008.01.027

Cited by 13 publications

(15 citation statements)

References 28 publications

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“…Both the hygroscopicity tandem differential mobility analyzer (HTDMA) (Henning et al, 2012;Khalizov et al, 2009;Qiu et al, 2014;Zhang et al, 2008) and ATR-IR spectroscopy (Lu et al, 2008a(Lu et al, , 2008bWang et al, 2008;Zhang et al, 2014) are widely used to characterize the hygroscopicity of particles. Using ATR-IR spectroscopy, the hygroscopicity of the bulk soot aggregates deposited on the ZnSe substrate is examined by observing the changes in the IR band of adsorbed water.…”

Section: Water Uptake and Hygroscopicity Of Sootmentioning

confidence: 99%

Influence of sulfur in fuel on the properties of diffusion flame soot

Zhao

2016

Atmospheric Environment

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h i g h l i g h t sLean flame soot was influenced more by sulfur in fuel than rich flame soot. Sulfate species were mainly formed on the surface of soot. The diameter of primary lean flame soot from high sulfur content fuel increased. The hygroscopicity of lean flame soot from high sulfur content fuel increased. a r t i c l e i n f o a b s t r a c tPrevious studies indicate that sulfur in fuel affects the hygroscopicity of soot. However, the issue of the effect of sulfur in fuel on soot properties is not fully understood. Here, the properties of soot prepared from fuel with a variable sulfur content were investigated under lean and rich flame conditions. Lean flame soot was influenced more by sulfur in fuel than rich flame soot. The majority of sulfur in fuel in lean flame was converted to gaseous SO 2 , while a small fraction appeared as sulfate and bisulfate (referred to as sulfate species) in soot. As the sulfur content in fuel increased, sulfate species in lean flame soot increased nonlinearly, while sulfate species on the surface of lean flame soot increased linearly. The hygroscopicity of lean flame soot from sulfur-containing fuel was enhanced mainly due to sulfate species. Meanwhile, more alkynes were formed in lean flame. The diameter of primary lean flame soot particles increased and accumulation mode particle number concentrations of lean flame soot from sulfurcontaining fuel increased as a result of more alkynes. Because the potential effects of soot particles on air pollution development greatly depend on the soot properties, which are related to both chemical aging and combustion conditions, this work will aid in understanding the impacts of soot on air quality and climate.

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Section: Water Uptake and Hygroscopicity Of Sootmentioning

confidence: 99%

Influence of sulfur in fuel on the properties of diffusion flame soot

Zhao

2016

Atmospheric Environment

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“…32 A simplified expression for the initial region of the uptake curve may be obtained as (7) where mt /m∞ is the fractional approach to the sorption equilibrium at time t, is the average water content in the droplet which depends on time, Dap is the apparent water diffusivity, S/V is the ratio of external surface area-to-particle volume which is S/V=3/Rp for a spherical particle of radius Rp. 32 A simplified expression for the initial region of the uptake curve may be obtained as (7) where mt /m∞ is the fractional approach to the sorption equilibrium at time t, is the average water content in the droplet which depends on time, Dap is the apparent water diffusivity, S/V is the ratio of external surface area-to-particle volume which is S/V=3/Rp for a spherical particle of radius Rp.…”

Section: Asynchronous Shifts In Wgms Of Different Mode Orders During mentioning

confidence: 99%

“…32 Indeed, the water content plays an important role in regulating the structures of hydrates. 32 Indeed, the water content plays an important role in regulating the structures of hydrates.…”

Section: Asynchronous Shifts In Wgms Of Different Mode Orders During mentioning

confidence: 99%

“…Among them, MgSO 4 aerosol has received attention due to its prevalence in sea salt aerosol. [28][29][30][31][32] Recent chemical and spectroscopic data have provided evidence for the occurrence of various hydrated Mg-sulfate minerals on the surface of Mars. 33,34 Following the suggestion that levitated MgSO 4 droplets form a gel at low RH, 14 a more systematic investigation of the deliquescence and efflorescence phase behavior was carried out using an EDB coupled with Raman spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

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Slow water transport in MgSO₄ aerosol droplets at gel-forming relative humidities

Cai

Tan

Chen

et al. 2015

Phys. Chem. Chem. Phys.

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The effect of gel formation on the mass transfer of water during evaporation or condensation from MgSO4 droplets is studied using aerosol optical tweezers coupled with Raman spectroscopy. In particular, the kinetics of water transport during hydration and dehydration are followed for variable step changes in relative humidity and compared with previous measurements using different methodologies. Slow diffusion of water in the particle bulk is shown to limit water evaporation and condensation from the aerosol. Desorption of water continues over a long time at the very low RH region and this is validated with complementary studies made by FTIR-ATR and measurements of water adsorption isotherms. The observations can be rationalized when considering the possible phase transformation of the gel structure at very low RHs. Finally, the influence of the duration of the drying time (RH ≤ 10%) on the kinetics of condensation during hydration is investigated. Apparent diffusion coefficients of water molecules in the gel are obtained, showing little dependence on the water activity and droplet composition, and are consistent with the slow removal of water during drying from pores formed at the gel transition RH.

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“…Although relative humidity was minimal in the afternoon at Kohnen Station , the minimum relative humidity (∼ 89 %) was often higher than the deliquescence relative humidity (DRH) of plausible sea-salts. Some examples are the following: NaCl, 75 % (Tang and Munkelwitz, 1993); Na 2 SO 4 , 84 % (Tang and Munkelwitz, 1994); NaNO 3 , 75 % (Tang and Munkelwitz, 1994); MgCl 2 6H 2 O, 33 % (Kelly and Wexler, 2005); MgSO 4 , 42 % (Wang et al, 2008); and KCl, 84 % (Tang, 1980). Most plausible sea-salts can be wholly deliquescent even under minimum relative humidity (∼ 89 %) on the Antarctic continent.…”

Section: Horizontal Features Of Sea-salt Fractionation On the Antarctmentioning

confidence: 99%

Horizontal distributions of aerosol constituents and their mixing states in Antarctica during the JASE traverse

Hara¹,

Nakazawa²,

Fujita³

et al. 2014

Preprint

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Abstract. Measurements of aerosol number concentrations and direct aerosol sampling were conducted on continental Antarctica during the traverse of Japanese–Swedish joint Antarctic expedition (JASE) from 14 November 2007 until 24 January 2008. Aerosol concentrations in background conditions decreased gradually with latitude in inland regions during the traverse. The lowest aerosol number concentrations were 160 L−1 in Dp > 0.3 μm, and 0.5 L−1 in Dp > 2 μm. In contrast, aerosol concentrations reached 3278 L−1 in Dp > 0.3 μm, and 215 L−1 in Dp > 2 μm under strong wind conditions. The estimated aerosol mass concentrations were 0.04–5.7 μg m−3. Single particle analysis of aerosol particles collected during the JASE traverse was conducted using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Major aerosol constituents were sulfates in fine mode, and sulfate, sea-salts, modified sea-salts, and fractionated sea-salts in coarse mode. K-rich sulfates, Mg-rich sulfate, Ca-rich sulfates, and minerals were identified as minor aerosol constituents. Sea-salt particles were modified greatly with SO42− and NO3− in coarse mode, and dominantly with SO42− in fine mode during the traverse. Most sea-salt particles in the continental region were modified with sulfate and methanesulfonate near the coast, although NO3− contributed markedly to sea-salt modification in inland areas during summer. Mg-rich sea-salt particles and Mg-free sea-salt particles were present in coarse and fine modes from the coast to inland areas. These sea-salt particles might be associated with sea-salt fractionation on the snow surface of continental Antarctica.

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Anomalous hygroscopic growth of fine particles of MgSO4 aerosols investigated by FTIR/ATR spectroscopy

Cited by 13 publications

References 28 publications

Influence of sulfur in fuel on the properties of diffusion flame soot

Influence of sulfur in fuel on the properties of diffusion flame soot

Slow water transport in MgSO₄ aerosol droplets at gel-forming relative humidities

Horizontal distributions of aerosol constituents and their mixing states in Antarctica during the JASE traverse

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Anomalous hygroscopic growth of fine particles of MgSO4 aerosols investigated by FTIR/ATR spectroscopy

Cited by 13 publications

References 28 publications

Influence of sulfur in fuel on the properties of diffusion flame soot

Influence of sulfur in fuel on the properties of diffusion flame soot

Slow water transport in MgSO4 aerosol droplets at gel-forming relative humidities

Horizontal distributions of aerosol constituents and their mixing states in Antarctica during the JASE traverse

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Slow water transport in MgSO₄ aerosol droplets at gel-forming relative humidities