Oxidation of aqueous SO/sub 2/ by peroxymonosulfate
Recent model calculations suggest that peroxymonosulfate may constitute a significant fraction of the total sulfur budget in remote tropospheric water droplets such as cloud, fog, and rain. However, little is known about the oxidation of dissolved SO/sub 2/ by peroxymonosulfate (HSO/sub 5//sup /minus//). The authors have found in aqueous solution that the rate of S(IV) oxidation is comparable to the rate of oxidation of S(IV) by hydrogen peroxide and that HSO/sub 4//sup /minus// is the only detectable oxidation product. They propose a mechanism in which the rate-determining step involves the acid-catalyzed decomposition of a peroxide-bisulfite intermediate to disulfate ion, S/sub 2/O/sub 7//sup 2 -/, and ultimately to sulfur acid. The rate equation for this mechanism is -d(HSO/sub 3//sup /minus//)/dt = k/sub 1/(k/sub 2//k/sub /minus/1/)K/sub a1/(H/sup +/)(HSO/sub 5//sup /minus//)(S(IV))/((1 + (k/sub 2//k/sub /minus/1/)(H/sup +/))(K/sub a1/ + (H/sup =/))), where k/sub 1/ = 1.21 /times/ 10/sup 6/ M/sup /minus/1/ s/sup /minus/1/, k/sub 2//k/sub /minus/1/ = 5.9 M/sup /minus/1/, k/sub 1/k/sub 2//k/sub /minus/1/ = 7.14 /times/ 10/sup 6/ M/sup /minus/2/ s/sup /minus/1/, K/sub a1/ = 2.64 /times/ 10/sup /minus/2/ M at 5/degrees/C, and ..mu.. = 0.2 M. The activation parameters are ..delta..H/sub k/sub 1// /double dagger/ = 25.74 /plus minus/ 0.77 kJ mol/sup /minus/1/ and ..delta..S/sub k/sub 1// /double dagger/ = /minus/88.1 /plus minus/ 2.7 J mol/sup /minus/1/ K/sup /minus/1/.
- Research Organization:
- California Institute of Technology, Pasadena (USA)
- OSTI ID:
- 6255312
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 92:21
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
54 ENVIRONMENTAL SCIENCES
PEROXIDES
REDUCTION
SULFATES
SULFUR OXIDES
OXIDATION
CHEMICAL REACTION KINETICS
EXPERIMENTAL DATA
PREDICTION EQUATIONS
SULFURIC ACID
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
EQUATIONS
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
KINETICS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SULFUR COMPOUNDS
400201* - Chemical & Physicochemical Properties
500100 - Environment
Atmospheric- Basic Studies- (-1989)