Studies of concentrated electrolyte solutions using the electrodynamic balance.  3.  Solute nucleation

Cohen, Mark; Flagan, Richard C.; Seinfeld, John H.

doi:10.1021/j100301a031

Cited by 112 publications

(102 citation statements)

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“…These values are consistent with previously reported values of 79% to 81% RH for deliquescence and 34% to 48% RH for efflorescence (e.g., Tang 1980; Richardson and Spann 1984;Cohen et al 1987aCohen et al , 1987bTang and Munkelwitz 1994).…”

Section: Rh Dependencesupporting

confidence: 93%

Design and Application of a Pulsed Cavity Ring-Down Aerosol Extinction Spectrometer for Field Measurements

Baynard

Lovejoy

Pettersson

et al. 2007

Aerosol Science and Technology

104

109

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This paper describes the design and application of a pulsed cavity ring-down aerosol extinction spectrometer (CRD-AES) for insitu atmospheric measurement of the aerosol extinction coefficient and its relative humidity dependence. This CRD-AES measures the aerosol extinction coefficient (σ ep ) at 355 nm, 532 nm, 683 nm, and 1064 nm with a minimal size dependent bias for particles with diameter less than 10 μm. The σ ep at 532 nm is measured with an accuracy of 1% when extinction is ≥10 Mm −1 . The precision is limited by statistical fluctuations within the small optical volume and the time resolution of extinction at 2% uncertainty for various air mass types is evaluated. The CRD-AES is configured with two separate cavity ring-down cells for measurement of the extinction coefficient at 532 nm. This allows the determination of the RH dependence of extinction at 532 nm through independent RH control of the sample for each measurement. Gas phase absorption and minimization of potential interferences is also considered.

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Section: Rh Dependencesupporting

confidence: 93%

Design and Application of a Pulsed Cavity Ring-Down Aerosol Extinction Spectrometer for Field Measurements

Baynard

Lovejoy

Pettersson

et al. 2007

Aerosol Science and Technology

104

109

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“…Efflorescence, however, is a kinetic or rate-driven process that requires a sufficient activation energy to overcome the kinetic barrier (Martin, 2000). This kinetic or critical-nucleation barrier in turn depends on a range of factors, such as the mixing states of the chemical components, micro-physical states, supersaturation levels, vapor pressure, interfacial tension, viscosity, inter-ionic forces, and solute-water and solute-solute interactions (Cohen et al, 1987b). Therefore, the ERHs of single or multi-component salts are difficult to predict theoretically (Seinfeld and Pandis, 2006).…”

Section: Gupta Et Al: Hygroscopic Properties Of Nacl and Nano 3 Mmentioning

confidence: 99%

Hygroscopic properties of NaCl and NaNO<sub>3</sub> mixture particles as reacted inorganic sea-salt aerosol surrogates

et al. 2015

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Abstract. NaCl in fresh sea-salt aerosol (SSA) particles can partially or fully react with atmospheric NO x /HNO 3 , so internally mixed NaCl and NaNO 3 aerosol particles can co-exist over a wide range of mixing ratios. Laboratorygenerated, micrometer-sized NaCl and NaNO 3 mixture particles at 10 mixing ratios (mole fractions of NaCl (X NaCl ) = 0.1 to 0.9) were examined systematically to observe their hygroscopic behavior, derive experimental phase diagrams for deliquescence and efflorescence, and understand the efflorescence mechanism. During the humidifying process, aerosol particles with the eutonic composition (X NaCl = 0.38) showed only one phase transition at their mutual deliquescence relative humidity (MDRH) of 67.9 (±0.5) %. On the other hand, particles with other mixing ratios showed two distinct deliquescence transitions; i.e., the eutonic component dissolved at MDRH, and the remainder in the solid phase dissolved completely at their DRHs depending on the mixing ratios, resulting in a phase diagram composed of four different phases, as predicted thermodynamically. During the dehydration process, NaCl-rich particles (X NaCl > 0.38) showed a two stage efflorescence transition: the first stage was purely driven by the homogeneous nucleation of NaCl and the second stage at the mutual efflorescence RH (MERH) of the eutonic components, with values in the range of 30.0-35.5 %. Interestingly, aerosol particles with the eutonic composition (X NaCl = 0.38) also showed two-stage efflorescence, with NaCl crystallizing first followed by heterogeneous nucleation of the remaining NaNO 3 on the NaCl seeds. NaNO 3 -rich particles (X NaCl ≤ 0.3) underwent singlestage efflorescence transitions at ERHs progressively lower than the MERH because of the homogeneous nucleation of NaCl and the almost simultaneous heterogeneous nucleation of NaNO 3 on the NaCl seeds. SEM/EDX elemental mapping indicated that the effloresced NaCl-NaNO 3 particles at all mixing ratios were composed of a homogeneously crystallized NaCl moiety in the center, surrounded either by the eutonic component (for X NaCl > 0.38) or NaNO 3 (for X NaCl ≤ 0.38). During the humidifying or dehydration process, the amount of eutonic composed part drives particle/droplet growth or shrinkage at the MDRH or MERH (second ERH), respectively, and the amount of pure salts (NaCl or NaNO 3 in NaCl-or NaNO 3 -rich particles, respectively) drives the second DRHs or first ERHs, respectively. Therefore, their behavior can be a precursor to the optical properties and direct radiative forcing for these atmospherically relevant mixture particles representing the coarse, reacted inorganic SSAs. In addition, the NaCl-NaNO 3 mixture aerosol particles can maintain an aqueous phase over a wider RH range than pure NaCl particles as SSA surrogate, making their heterogeneous chemistry more probable.

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“…The bulk of experimental evidence 20 and previous attempts of atomistic modelling [21][22][23][24] suggest that the efflorescence of NaCl in microscopic NaCl or SSA solution droplets is controlled by kinetic effects and should be treated within the framework of Classical Nucleation Theory (CNT) for homogeneous or heterogeneous nucleation. 12,25,26 A reliable CNT-based parameterization is, however, missing due to the absence of experimental data on key parameters such as diffusivities of water and ionic species and interfacial energies for the crystalline phase in contact with supersaturated solute in the low temperature range, i.e., below 240 K. To mitigate this problem, we use a humidified electrodynamic balance (EDB) coupled with a Raman microscope to measure the volume specific nucleation rates (also called nucleation rate coefficients) of NaCl and NaCl dihydrate in suspended droplets of aqueous NaCl solution at different temperatures. Based on these measurements, we estimate the interfacial energy of NaCl dihydrate in the concentrated NaCl solution.…”

Section: Introductionmentioning

confidence: 99%

Temperature-dependent formation of NaCl dihydrate in levitated NaCl and sea salt aerosol particles

Peckhaus¹,

Kiselev²,

Wagner³

et al. 2016

The Journal of Chemical Physics

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Recent laboratory studies indicate that the hydrated form of crystalline NaCl is potentially important for atmospheric processes involving depositional ice nucleation on NaCl dihydrate particles under cirrus cloud conditions. However, recent experimental studies reported a strong discrepancy between the temperature intervals where the efflorescence of NaCl dihydrate has been observed. Here we report the measurements of the volume specific nucleation rate of crystalline NaCl in the aqueous solution droplets of pure NaCl suspended in an electrodynamic balance at constant temperature and humidity in the range from 250 K to 241 K. Based on these measurements, we derive the interfacial energy of crystalline NaCl dihydrate in a supersaturated NaCl solution and determined its temperature dependence. Taking into account both temperature and concentration dependence of nucleation rate coefficients, we explain the difference in the observed fractions of NaCl dihydrate reported in the previous studies. Applying the heterogeneous classical nucleation theory model, we have been able to reproduce the 5 K shift of the NaCl dihydrate efflorescence curve observed for the sea salt aerosol particles, assuming the presence of super-micron solid inclusions (hypothetically gypsum or hemihydrate of CaSO 4 ). These results support the notion that the phase transitions in microscopic droplets of supersaturated solution should be interpreted by accounting for the stochastic nature of homogeneous and heterogeneous nucleation and cannot be understood on the ground of bulk phase diagrams alone.

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Studies of concentrated electrolyte solutions using the electrodynamic balance. 3. Solute nucleation

Cited by 112 publications

References 0 publications

Design and Application of a Pulsed Cavity Ring-Down Aerosol Extinction Spectrometer for Field Measurements

Design and Application of a Pulsed Cavity Ring-Down Aerosol Extinction Spectrometer for Field Measurements

Hygroscopic properties of NaCl and NaNO<sub>3</sub> mixture particles as reacted inorganic sea-salt aerosol surrogates

Temperature-dependent formation of NaCl dihydrate in levitated NaCl and sea salt aerosol particles

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Studies of concentrated electrolyte solutions using the electrodynamic balance. 3. Solute nucleation

Cited by 112 publications

References 0 publications

Design and Application of a Pulsed Cavity Ring-Down Aerosol Extinction Spectrometer for Field Measurements

Design and Application of a Pulsed Cavity Ring-Down Aerosol Extinction Spectrometer for Field Measurements

Hygroscopic properties of NaCl and NaNO&lt;sub&gt;3&lt;/sub&gt; mixture particles as reacted inorganic sea-salt aerosol surrogates

Temperature-dependent formation of NaCl dihydrate in levitated NaCl and sea salt aerosol particles

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Hygroscopic properties of NaCl and NaNO<sub>3</sub> mixture particles as reacted inorganic sea-salt aerosol surrogates