Abstract
The reaction of sulfur dioxide and hydrogen peroxide in the presence of deliquesced (>75% RH) sodium chloride (brine) particles was studied by utilizing a cross flow mini-reactor. The reaction kinetics were followed by observing chloride depletion in particles by computer-controlled scanning electron microscope with energy dispersive X-ray analysis, namely CCSEM/EDX. The reactions take place in concentrated mixed salt brine aerosols, for which no complete kinetic equilibrium data previously existed. We measured the Henry's law solubility of H2O2 in brine solutions to close that gap. We also calculated the reaction rate as the particle transforms continuously from concentrated NaCl brine to, eventually, a mixed NaHSO4 plus H2SO4 brine solution. The reaction rate of the SO2 oxidation by H2O2 was found to be influenced by the change in ionic strength as the particle undergoes compositional transformation, following closely the dependence of the third order rate constant on ionic strength as predicted using established rate equations. This is the first study that has measured the ionic strength dependence of sulfate formation (in non-aqueous media) from oxidation of mixed salt brine aerosols in the presence of H2O2. It also gives the first report of the dependence of the Henry's law constant of H2O2 on ionic strength.
Original language | English |
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Pages (from-to) | 731-738 |
Number of pages | 8 |
Journal | Atmospheric Environment |
Volume | 89 |
DOIs | |
State | Published - Jun 2014 |
Externally published | Yes |
Funding
The work was supported by the US Department of Energy under the auspices of the Atmospheric Science Program, under contract DE-AC05-76RL01830/KP1701000/57131, by the National Oceanic and Atmospheric Administration under the auspices of the Atmospheric Composition and Climate Program under the sub contract 47840, a DOE/BES Chemical Science grant (KC-0301020-16248). The research was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national user facility sponsored by the Department of Energy's Office of Biological and Environmental Research (OBER) and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated by the US DOE by Battelle Memorial Institute. Some of the analysis was also performed at Arkansas State University – Jonesboro.
Funders | Funder number |
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OBER | |
U.S. Department of Energy | DE-AC05-76RL01830/KP1701000/57131 |
National Oceanic and Atmospheric Administration | 47840 |
Basic Energy Sciences | KC-0301020-16248 |
Biological and Environmental Research | |
Pacific Northwest National Laboratory |
Keywords
- Brine
- Ionic strength
- Oxidation
- Sodium chloride
- Sulfate