scholarly journals Computation of liquid-liquid equilibria and phase stabilities: implications for RH-dependent gas/particle partitioning of organic-inorganic aerosols

2010 ◽  
Vol 10 (16) ◽  
pp. 7795-7820 ◽  
Author(s):  
A. Zuend ◽  
C. Marcolli ◽  
T. Peter ◽  
J. H. Seinfeld

Abstract. Semivolatile organic and inorganic aerosol species partition between the gas and aerosol particle phases to maintain thermodynamic equilibrium. Liquid-liquid phase separation into an organic-rich and an aqueous electrolyte phase can occur in the aerosol as a result of the salting-out effect. Such liquid-liquid equilibria (LLE) affect the gas/particle partitioning of the different semivolatile compounds and might significantly alter both particle mass and composition as compared to a one-phase particle. We present a new liquid-liquid equilibrium and gas/particle partitioning model, using as a basis the group-contribution model AIOMFAC (Zuend et al., 2008). This model allows the reliable computation of the liquid-liquid coexistence curve (binodal), corresponding tie-lines, the limit of stability/metastability (spinodal), and further thermodynamic properties of multicomponent systems. Calculations for ternary and multicomponent alcohol/polyol-water-salt mixtures suggest that LLE are a prevalent feature of organic-inorganic aerosol systems. A six-component polyol-water-ammonium sulphate system is used to simulate effects of relative humidity (RH) and the presence of liquid-liquid phase separation on the gas/particle partitioning. RH, salt concentration, and hydrophilicity (water-solubility) are identified as key features in defining the region of a miscibility gap and govern the extent to which compound partitioning is affected by changes in RH. The model predicts that liquid-liquid phase separation can lead to either an increase or decrease in total particulate mass, depending on the overall composition of a system and the particle water content, which is related to the hydrophilicity of the different organic and inorganic compounds. Neglecting non-ideality and liquid-liquid phase separations by assuming an ideal mixture leads to an overestimation of the total particulate mass by up to 30% for the composition and RH range considered in the six-component system simulation. For simplified partitioning parametrizations, we suggest a modified definition of the effective saturation concentration, Cj*, by including water and other inorganics in the absorbing phase. Such a Cj* definition reduces the RH-dependency of the gas/particle partitioning of semivolatile organics in organic-inorganic aerosols by an order of magnitude as compared to the currently accepted definition, which considers the organic species only.

2010 ◽  
Vol 10 (5) ◽  
pp. 12497-12561 ◽  
Author(s):  
A. Zuend ◽  
C. Marcolli ◽  
T. Peter ◽  
J. H. Seinfeld

Abstract. Semivolatile organic and inorganic aerosol species partition between the gas and aerosol particle phases to maintain thermodynamic equilibrium. Liquid-liquid phase separation into an organic-rich and an aqueous electrolyte phase can occur in the aerosol as a result of the salting-out effect. Such liquid-liquid equilibria (LLE) affect the gas/particle partitioning of the different semivolatile compounds and might significantly alter both particle mass and composition as compared to a one-phase particle. We present a new liquid-liquid equilibrium and gas/particle partitioning model, using as a basis the group-contribution model AIOMFAC (Zuend et al., 2008). This model allows the reliable computation of the liquid-liquid coexistence curve (binodal), corresponding tie-lines, the limit of stability/metastability (spinodal), and further thermodynamic properties of the phase diagram. Calculations for ternary and multicomponent alcohol/polyol-water-salt mixtures suggest that LLE are a prevalent feature of organic-inorganic aerosol systems. A six-component polyol-water-ammonium sulphate system is used to simulate effects of relative humidity (RH) and the presence of liquid-liquid phase separation on the gas/particle partitioning. RH, salt concentration, and hydrophilicity (water-solubility) are identified as key features in defining the region of a miscibility gap and govern the extent to which compound partitioning is affected by changes in RH. The model predicts that liquid-liquid phase separation can lead to either an increase or decrease in total particulate mass, depending on the overall composition of a system and the particle water content, which is related to the hydrophilicity of the different organic and inorganic compounds. Neglecting non-ideality and liquid-liquid phase separations by assuming an ideal mixture leads to an overestimation of the total particulate mass by up to 30% for the composition and RH range considered in the six-component system simulation. For simplified partitioning parametrizations, we suggest a modified definition of the effective saturation concentration, C*j, by including water and other inorganics in the absorbing phase. Such a C*j definition reduces the RH-dependency of the gas/particle partitioning of semivolatile organics in organic-inorganic aerosols by an order of magnitude as compared to the currently accepted definition, which considers the organic species only.


2020 ◽  
Vol 993 ◽  
pp. 39-44
Author(s):  
Xiao Jun Sun ◽  
Jie He ◽  
Jiu Zhou Zhao

The binary Cu-Fe system is characterized by a metastable liquid miscibility gap. WhenZr is added into the Cu-Fe alloy, the miscibility gap can be extended into Cu-Fe-Zr ternary system. In the present study Cu-Fe-Zr alloys were prepared by single-roller melting-spinning method, and the samples were characterized by the SEM, EDS, HRTEM and nanoidentation. The results show that liquid-liquid phase separation into CuZr-rich and FeZr-rich liquids takes place during rapid cooling the Cu-Fe-Zr alloy, and the mechanism depends on the atomic ratio of Cu to Fe. With increasing Zr content, the size of secondary phase formed by the liquid-liquid phase separation reduces to nanoscale. The structure with amorphous Cu-rich nanoparticles embedded in the amorphous Fe-rich matrix was obtained in the as-quenched Cu20Fe20Zr60 alloy. For its structure particularity of the Cu20Fe20Zr60 sample, mechanical evaluation was carried out by using nanoindentation.


2009 ◽  
Vol 113 (41) ◽  
pp. 10966-10978 ◽  
Author(s):  
V. Gabriela Ciobanu ◽  
Claudia Marcolli ◽  
Ulrich K. Krieger ◽  
Uwe Weers ◽  
Thomas Peter

2021 ◽  
Vol 433 (2) ◽  
pp. 166731
Author(s):  
Yanxian Lin ◽  
Yann Fichou ◽  
Andrew P. Longhini ◽  
Luana C. Llanes ◽  
Pengyi Yin ◽  
...  

Author(s):  
Yanting Xing ◽  
Aparna Nandakumar ◽  
Aleksandr Kakinen ◽  
Yunxiang Sun ◽  
Thomas P. Davis ◽  
...  

2021 ◽  
Author(s):  
Kazuki Murakami ◽  
Shinji Kajimoto ◽  
Daiki Shibata ◽  
Kunisato Kuroi ◽  
Fumihiko Fujii ◽  
...  

Liquid–liquid phase separation (LLPS) plays an important role in a variety of biological processes and is also associated with protein aggregation in neurodegenerative diseases. Quantification of LLPS is necessary to...


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