A Study of Heterogeneous Nucleation in Aqueous Solutions

Richardson, C. B.; Snyder, Tamara D.

doi:10.1021/la00019a072

Cited by 51 publications

(61 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The supersaturation of the solute has been calculated following the method of Richardson and Snyder. 61 In this method, the ratio of the mole fraction of water x w to the mole fraction of solute x s is expressed as a function of the negative logarithm of the water activity in the NaCl solution. The supersaturation at efflorescence can be calculated as follows: 62 ln S * = a w,del a w,eff…”

Section: F Cnt-based Simulation Of Experimental Resultsmentioning

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

View full text Add to dashboard Cite

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.

show abstract

Section: F Cnt-based Simulation Of Experimental Resultsmentioning

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

View full text Add to dashboard Cite

show abstract

“…The following quantitative treatment is adopted from the work of Richardson and Snyder [1994] which examines the heterogeneous nucleation behavior of soluble mixed salts. Within this treatment, the following assumptions have been made: (1) a single nucleation event is observed and initiated from a single critical nucleus; (2) the seed particle is pure CaCO3 or BaSOn.…”

Section: Discussionmentioning

confidence: 99%

“…The heterogeneous nucleation rate is proportional to the surface area A of the seed nucleus present in the levitated drop and can be expressed as: number of molecules in a unit cell; 2size of unit cell in Angstrom. J = AJoe 'w*/kT (1) [Richardson and Snyder, 1994], where W* is the nucleation barrier height equal to the reversible work required to form the critical nucleus, and the kinetic pre-factor is the product of an intensive factor Jo (crff2s ' Table 1. The data show that the presence of a solid impurity significantly decreases the critical supersaturation required for crystallization to occur.…”

Section: Discussionmentioning

confidence: 99%

“…Although the preceding analysis does not require a specific model for the heterogeneous nucleus, an analysis can be carried out using the well-known spherical cap model (e.g., Richardson and Snyder, 1994 unit cell lattice, mismatches of about 0.5 and 1 angstrom. CaCO3, on the other hand, belongs to a different symmetry group and has a very different crystalline structure.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Heterogeneous nucleation of a common atmospheric aerosol: Ammonium sulfate

Oatis

Imre

McGraw

et al. 1998

Geophysical Research Letters

View full text Add to dashboard Cite

Abstract. Natural and anthropogenic aerosols have a direct impact on the earth's radiative balance. Many of the common atmospheric aerosols contain hygroscopic salts and therefore their physical state and composition are sensitive to the relative humidity. The phase of the aerosol particle will dramatically affect the relative rates of atmospheric reactions, and radiative properties such as scattering and optical activity. In order to understand these atmospheric processes and provide accurate input for global modeling, it is imperative that these phase transitions be well defined. It is thought that the degree of metastability is influenced by the presence of foreign particulate matter. These solid impurities are predicted to reduce the barrier of nucleation by providing a surface upon which heterogeneous nucleation can be catalyzed. We report the results of CaCO3 and BaSOn solid impurities on the efflorescence of (NHn)2SOa-H20 micro-droplets. The results show that both solid impurities act as catalysts for heterogeneous nucleation by causing a decrease in the degree of metastability at the efflorescence point. BaSOn does not prove to be significantly more efficient than CaCO3 in spite of having the same crystalline structure and similar lattice parameters as in (NH4)2SO4.

show abstract

“…• C. 22 Using ESEM, it was shown that the water film contained dissolved Na + and Cl − ions and an outer liquid layer of approximately the same volume as the crystal core for relative humidities up to 3% below the equilibrium RH of the solution was found. 4 ESEM micrographs also showed that the solid and liquid are simultaneously present in significant amounts from 70% to 75% RH.…”

Section: The Influence Of the Control Modementioning

confidence: 99%

High accuracy calibration of a dynamic vapor sorption instrument and determination of the equilibrium humidities using single salts

Rörig-Dalgaard

Svensson

2016

Review of Scientific Instruments

View full text Add to dashboard Cite

We present a procedure for accurately calibrating a dynamic vapor sorption (DVS) instrument using single salts. The procedure accounts for and tailors distinct calibration tests according to the fundamental properties of each salt. Especially relevant properties influencing the calibration are the heat of solution, heat of condensation, and the kinetics connected to the salt phase transition, as these influence the microclimate surrounding the salts during calibration. All these issues were dealt with to obtain precise calibration results. The DVS instrument comprises two control modes to generate and measure the relative humidity (RH). Both control modes were separately examined and combined to overcome the shortcomings of each of the two control modes and thereby obtain the most accurate results. Repeated calibration testing with the single salts (LiCl, MgCl2, Mg(NO3)2, NaCl, and KNO3) enables five discrete sorption isotherm measurements within the range of 11%–93%RH. The equilibrium RH of the solution for LiCl, MgCl2, Mg(NO3)2, NaCl, and KNO3 was determined with a standard deviation of 0.06%-0.15% (0.45% for KNO3) RH. By comparing the measured calibration values with the well-known equilibrium RH of each salt solution, the presented method’s results are both accurate with significant agreement and precise with small variation.

show abstract

A Study of Heterogeneous Nucleation in Aqueous Solutions

Cited by 51 publications

References 0 publications

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

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

Heterogeneous nucleation of a common atmospheric aerosol: Ammonium sulfate

High accuracy calibration of a dynamic vapor sorption instrument and determination of the equilibrium humidities using single salts

Contact Info

Product

Resources

About