| Autor: |
Losey DJ; Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States., Parker RG; Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States., Freedman MA; Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States. |
| Jazyk: |
angličtina |
| Zdroj: |
The journal of physical chemistry letters [J Phys Chem Lett] 2016 Oct 06; Vol. 7 (19), pp. 3861-3865. Date of Electronic Publication: 2016 Sep 19. |
| DOI: |
10.1021/acs.jpclett.6b01621 |
| Abstrakt: |
Atmospheric aerosol particles influence climate through their direct and indirect effects. These impacts depend in part on the morphology of the particles, which is determined by their composition. The effect of pH on morphology was investigated using particles composed of 3-methylglutaric acid and ammonium sulfate by manipulating the starting pH of the bulk solution through the addition of aqueous sodium hydroxide. Efflorescence, deliquescence, phase separation, and mixing transitions were observed with optical microscopy. Due to changes in its protonation states, the solubility of the organic component increases with increasing pH, which shifts the location of the separation relative humidity (SRH) from 78.7% for the fully protonated acid to 63.9% for the fully deprotonated acid. Surprisingly, this shift in the SRH leads to hysteresis between the SRH and the mixing relative humidity (MRH). Particle pH has the greatest effect on phase transitions that require nucleus formation, that is, efflorescence and SRH. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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