Measuring the water activity of ternary aerosol systems and generating phase diagrams for sub micron aerosol particles
Open Access
Author:
Poitras, Haley
Graduate Program:
Chemistry
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
August 17, 2021
Committee Members:
Philip Bevilacqua, Program Head/Chair Miriam Arak Freedman, Thesis Advisor/Co-Advisor Christine Dolan Keating, Committee Member Scott A Showalter, Committee Member Kenneth James Davis, Committee Member
Keywords:
Water activity phase separation
Abstract:
The water activity of ternary aerosol systems was studied to understand the behavior of each component. The components were 2-methylglutaric acid and ammonium sulfate with a varying organic molecule to make up the third component. Sucrose and glycerol were modeled in depth and were shown to have differing trends in water activity. As the mole fraction of sucrose increased the water activity increased. As the mole fraction of glycerol increased the water activity decreased. Furthermore, phase diagrams were modeled for systems to see how the addition of functional groups on hexane change the separation relative humidity (SRH) of the system. The functional groups of alcohols, ethers, esters, ketones, carboxylic acids, and aldehydes were explored and showed that as the number of functional groups increased the separation relative humidity decreased. Additionally, other systems were modeled to see how the oxygen to carbon (O:C) ratio varied the SRH of the system. The organic compounds explored were 2,5-hexanediol, 1,2,6-hexanetriol, alpha,4-dihydroxy-3-methoxybenzeneacetic acid, diethylmalonic acid, 3,3-dimethylglutaric acid, and 2-methylglutaric acid and were modeled with ammonium sulfate. The phase diagrams showed that the SRH for these systems were 94%, 87%, 98%, 94%, 93%, and 83%, in respect to the organic compounds mentioned above.
