Liquid-liquid phase separation and morphology of internally mixed dicarboxylic acids/ammonium sulfate/water particles

Song, Mijung; Marcolli, Claudia; Krieger, Ulrich K.; Zuend, Andreas; Peter, Thomas

doi:10.5194/acp-12-2691-2012

Cited by 179 publications

(333 citation statements)

References 75 publications

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“…7,9 The interfacial tensions, in turn, depend on the compositions of the phases; therefore, the particle morphology changes in response to substantial variations in RH. 9,10 In the case of core-shell structure with a semi-solid or glassy organic shell phase, mass transfer of water and organic compounds can be kinetically limited; 15,25 implications of this situation are discussed below. Fig.…”

Section: Introductionmentioning

confidence: 99%

Gas–particle partitioning of atmospheric aerosols: interplay of physical state, non-ideal mixing and morphology

Shiraiwa

Zuend

Bertram

et al. 2013

Phys. Chem. Chem. Phys.

246

268

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Atmospheric aerosols, comprising organic compounds and inorganic salts, play a key role in air quality and climate. Mounting evidence exists that these particles frequently exhibit phase separation into predominantly organic and aqueous electrolyte-rich phases. As well, the presence of amorphous semi-solid or glassy particle phases has been established. Using the canonical system of ammonium sulfate mixed with organics from the ozone oxidation of a-pinene, we illustrate theoretically the interplay of physical state, non-ideality, and particle morphology affecting aerosol mass concentration and the characteristic timescale of gas-particle mass transfer. Phase separation can significantly affect overall particle mass and chemical composition. Semi-solid or glassy phases can kinetically inhibit the partitioning of semivolatile components and hygroscopic growth, in contrast to the traditional assumption that organic compounds exist in quasi-instantaneous gas-particle equilibrium. These effects have significant implications for the interpretation of laboratory data and the development of improved atmospheric air quality and climate models.

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Section: Introductionmentioning

confidence: 99%

Gas–particle partitioning of atmospheric aerosols: interplay of physical state, non-ideal mixing and morphology

Shiraiwa

Zuend

Bertram

et al. 2013

Phys. Chem. Chem. Phys.

246

268

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“…As noted above, liquid-liquid phase separation may occur in aerosol particles consisting of organic and inorganic species. In the present SA/SOA case, this would result in one phase consisting predominantly of SA with minor contributions from organics, and another phase that is organic-rich but also contains significant SA (typically between 10 to 30 % of dry solute mass, see Song et al, 2012). Moreover, the organic phase is very likely to constitute the outer phase, while the inorganic SA phase is more likely to be located in the core of a particle due to a minimization of the overall surface energy of the particle the particle core may be liquid for the entire range of investigated humidity studied here.…”

Section: Phase State and Humidity-induced Phase Transitions Of Mixed mentioning

confidence: 99%

“…It is important to consider that in the case of multicomponent inorganic-organic particles it is possible that a liquid-liquid phase separation may occur (Marcolli and Krieger, 2006;Ciobanu et al, 2009;Bertram et al, 2011;Song et al, 2012;Zuend and Seinfeld, 2012). Since we cannot distinguish phase separation in the 100 nm particles studied here, we discuss below whether the observed bounce behavior is consistent with one or both of the two possible cases, i.e.…”

Section: Phase State and Humidity-induced Phase Transitions Of Mixed mentioning

confidence: 99%

Humidity-dependent phase state of SOA particles from biogenic and anthropogenic precursors

et al. 2012

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Abstract. The physical phase state (solid, semi-solid, or liquid) of secondary organic aerosol (SOA) particles has important implications for a number of atmospheric processes. We report the phase state of SOA particles spanning a wide range of oxygen to carbon ratios (O / C), used here as a surrogate for SOA oxidation level, produced in a flow tube reactor by photo-oxidation of various atmospherically relevant surrogate anthropogenic and biogenic volatile organic compounds (VOCs). The phase state of laboratory-generated SOA was determined by the particle bounce behavior after inertial impaction on a polished steel substrate. The measured bounce fraction was evaluated as a function of relative humidity and SOA oxidation level (O / C) measured by an Aerodyne high resolution time of flight aerosol mass spectrometer (HR-ToF AMS).The main findings of the study are: (1) biogenic and anthropogenic SOA particles are found to be amorphous solid or semi-solid based on the measured bounced fraction (BF), which was typically higher than 0.6 on a 0 to 1 scale. A decrease in the BF is observed for most systems after the SOA is exposed to relative humidity of at least 80 % RH, corresponding to a RH at impaction of 55 %. (2) Long-chain alkanes have a low BF (indicating a "liquid-like", less viscous phase) particles at low oxidation levels (BF < 0.2 ± 0.05 for O / C = 0.1). However, BF increases substantially upon increasing oxidation. (3) Increasing the concentration of sulphuric acid (H 2 SO 4 ) in solid SOA particles (here tested for longifolene SOA) causes a decrease in BF levels. (4) In the majority of cases the bounce behavior of the various SOA systems did not show correlation with the particle O / C. Rather, the molar mass of the gas-phase VOC precursor showed a positive correlation with the resistance to the RH-induced phase change of the formed SOA particles.

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“…In turn, these interactions influ9994 G. Ganbavale et al: Temperature dependency in aqueous organic solutions such as physical state, hygroscopicity, size, and shape (e.g. Ming and Russell, 2002;Kanakidou et al, 2005;Zobrist et al, 2008;Ciobanu et al, 2009;Mikhailov et al, 2009;Reid et al, 2011;Song et al, 2012). The light scattering intensity of aerosols depends on growth and evaporation of the particles due to uptake and release of water vapour driven by changes in ambient relative humidity (RH) (Carrico et al, 2003;Baynard et al, 2006;Zieger et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Experimental determination of the temperature dependence of water activities for a selection of aqueous organic solutions

et al. 2014

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Abstract. This work presents experimental data of the temperature dependence of water activity in aqueous organic solutions relevant for tropospheric conditions (200-273 K). Water activity (a w ) at low temperatures (T ) is a crucial parameter for predicting homogeneous ice nucleation. We investigated temperature-dependent water activities, ice freezing and melting temperatures of solutions, and vapour pressures of a selection of atmospherically relevant aqueous organic systems. To measure a w over a wide composition range and with a focus on low temperatures, we use various a w measurement techniques and instruments: a dew point water activity meter, an electrodynamic balance (EDB), differential scanning calorimetry (DSC), and a setup to measure the total gas phase pressure at equilibrium over aqueous solutions. Water activity measurements were performed for aqueous multicomponent and multifunctional organic mixtures containing the functional groups typically found in atmospheric organic aerosols, such as hydroxyl, carboxyl, ketone, ether, ester, and aromatic groups. The aqueous organic systems studied at several fixed compositions over a considerable temperature range differ significantly in their temperature dependence. Aqueous organic systems of 1,4-butanediol and methoxyacetic acid show a moderate decrease in a w with decreasing temperature. The aqueous M5 system (a multicomponent system containing five different dicarboxylic acids) and aqueous 2-(2-ethoxyethoxy)ethanol solutions both show a strong increase of water activity with decreasing temperature at high solute concentrations for T < 270 K and T < 260 K, respectively. These measurements show that the temperature trend of a w can be reversed at low temperatures and that linear extrapolations of high-temperature data may lead to erroneous predictions. To avoid this, experimentally determined a w at low temperature are needed to improve thermodynamic models towards lower temperatures and for improved predictions of the ice nucleation ability of organicwater systems.

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Liquid-liquid phase separation and morphology of internally mixed dicarboxylic acids/ammonium sulfate/water particles

Cited by 179 publications

References 75 publications

Gas–particle partitioning of atmospheric aerosols: interplay of physical state, non-ideal mixing and morphology

Gas–particle partitioning of atmospheric aerosols: interplay of physical state, non-ideal mixing and morphology

Humidity-dependent phase state of SOA particles from biogenic and anthropogenic precursors

Experimental determination of the temperature dependence of water activities for a selection of aqueous organic solutions

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