Hygroscopic and phase separation properties of ammonium sulfate/organics/water ternary solutions

Zawadowicz, MA; Proud, SR, SR; Seppalainen, SS; Cziczo, DJ

HERO ID

3015678

Reference Type

Journal Article

Year

2015

Language

English

HERO ID 3015678
In Press No
Year 2015
Title Hygroscopic and phase separation properties of ammonium sulfate/organics/water ternary solutions
Authors Zawadowicz, MA; Proud, SR, SR; Seppalainen, SS; Cziczo, DJ
Journal Atmospheric Chemistry and Physics
Volume 15
Issue 15
Page Numbers 8975-8986
Abstract Atmospheric aerosol particles are often partially or completely composed of inorganic salts, such as ammonium sulfate and sodium chloride, and therefore exhibit hygroscopic properties. Many inorganic salts have well-defined deliquescence and efflorescence points at which they take up and lose water, respectively. Field measurements have shown that atmospheric aerosols are not typically pure inorganic salt, instead, they often also contain organic species. There is ample evidence from laboratory studies that suggests that mixed particles exist in a phase-separated state, with an aqueous inorganic core and organic shell. Although phase separation has not been measured in situ, there is no reason it would not also take place in the atmosphere. Here, we investigate the deliquescence and efflorescence points, phase separation and ability to exchange gas-phase components of mixed organic and inorganic aerosol using a flow tube coupled with FTIR (Fourier transform infrared) spectroscopy. Ammonium sulfate aerosol mixed with organic polyols with different O : C ratios, including 1,4-butanediol, glycerol, 1,2,6-hexanetriol, 1,2-hexanediol, and 1,5-pentanediol have been investigated. Those constituents correspond to materials found in the atmosphere in great abundance and, therefore, particles prepared in this study should mimic atmospheric mixed-phase aerosol particles. Some results of this study tend to be in agreement with previous microscopy experiments, but others, such as phase separation properties of 1,2,6-hexanetriol, do not agree with previous work. Because the particles studied in this experiment are of a smaller size than those used in microscopy studies, the discrepancies found could be a size-related effect.
Doi 10.5194/acp-15-8975-2015
Wosid WOS:000359949700021
Is Certified Translation No
Dupe Override No
Is Public Yes
Language Text English
Keyword Infrared spectroscopy; Aerosols; Fourier transforms; Atmospheric chemistry; Sodium chloride; Ammonium compounds; Aerosol particles; Organic aerosols in atmosphere; Sulfate aerosols; Sulfates; Ammonium; Salts; Laboratories; Microscopy; Tubes; Atmosphere; 2015)
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