Abstract
The Henry coefficient of NO{sub 3} radicals, K{sub h}(NO{sub 3}), was studied in coiled denuder tubes of 2 mm diameter and variable length, e.g. 4-350 cm. The radicals were produced in a flow system by oxidation of NO with excess O{sub 3} at a temperature of 393 K. A small flow of pure H{sub 2}O was metered to the gas-flow and allowed to form a thin film on the denuder wall. Behind the denuder, gas and liquid were separated and the concentration of the dissolved NO{sub 3} was determined indirectly, after conversion to nitrate by reaction with Cl{sup -}-ions, which were added to the effluent of the denuder. The partial pressure of NO{sub 3} in the gas-phase behind the denuder was determined by quantitative conversion to nitrate in another denuder. The same experimental set-up was used to determine the mass accommodation coefficient of NO{sub 3} to an aqueous surface. There, a high Cl{sup -}-concentration (0.1 M) was used in the stripping solution to efficiently convert the dissolved NO{sub 3} to NO{sub 3-} and thus prevent phase-equilibrium to be reached. The mass accommodation coefficient was derived from the transmittance of the denuder as a function of length. The method requires the
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Citation Formats
Thomas, K, Volz-Thomas, A, and Kley, D.
On the interaction of NO{sub 3} radicals with aqueous solutions: Estimation of the Henry coefficient and the mass accomodation coefficient; Zur Wechselwirkung von NO{sub 3}-Radikalen mit waessrigen Loesungen: Bestimmung des Henry- und des Massenakkommodationskoeffizienten.
Germany: N. p.,
1993.
Web.
Thomas, K, Volz-Thomas, A, & Kley, D.
On the interaction of NO{sub 3} radicals with aqueous solutions: Estimation of the Henry coefficient and the mass accomodation coefficient; Zur Wechselwirkung von NO{sub 3}-Radikalen mit waessrigen Loesungen: Bestimmung des Henry- und des Massenakkommodationskoeffizienten.
Germany.
Thomas, K, Volz-Thomas, A, and Kley, D.
1993.
"On the interaction of NO{sub 3} radicals with aqueous solutions: Estimation of the Henry coefficient and the mass accomodation coefficient; Zur Wechselwirkung von NO{sub 3}-Radikalen mit waessrigen Loesungen: Bestimmung des Henry- und des Massenakkommodationskoeffizienten."
Germany.
@misc{etde_10122259,
title = {On the interaction of NO{sub 3} radicals with aqueous solutions: Estimation of the Henry coefficient and the mass accomodation coefficient; Zur Wechselwirkung von NO{sub 3}-Radikalen mit waessrigen Loesungen: Bestimmung des Henry- und des Massenakkommodationskoeffizienten}
author = {Thomas, K, Volz-Thomas, A, and Kley, D}
abstractNote = {The Henry coefficient of NO{sub 3} radicals, K{sub h}(NO{sub 3}), was studied in coiled denuder tubes of 2 mm diameter and variable length, e.g. 4-350 cm. The radicals were produced in a flow system by oxidation of NO with excess O{sub 3} at a temperature of 393 K. A small flow of pure H{sub 2}O was metered to the gas-flow and allowed to form a thin film on the denuder wall. Behind the denuder, gas and liquid were separated and the concentration of the dissolved NO{sub 3} was determined indirectly, after conversion to nitrate by reaction with Cl{sup -}-ions, which were added to the effluent of the denuder. The partial pressure of NO{sub 3} in the gas-phase behind the denuder was determined by quantitative conversion to nitrate in another denuder. The same experimental set-up was used to determine the mass accommodation coefficient of NO{sub 3} to an aqueous surface. There, a high Cl{sup -}-concentration (0.1 M) was used in the stripping solution to efficiently convert the dissolved NO{sub 3} to NO{sub 3-} and thus prevent phase-equilibrium to be reached. The mass accommodation coefficient was derived from the transmittance of the denuder as a function of length. The method requires the knowledge of the diffusion coefficient, which was determined in separate experiments conducted under the same conditions with HNO{sub 3}. The mass accommodation coefficient of NO{sub 3} was found to be {>=}2.5.10{sup -3}. Theoretical considerations and time-dependent box-model calculations show that even under favourable conditions, heterogeneous losses of NO{sub 3} are important for the budget of NO{sub x} only, if NO{sub x}-concentrations are below 0.5 ppb. At higher NO{sub x}-concentrations, the night-time losses proceed predominantly via N{sub 2}O{sub 5}. In the maritime boundary layer, night-time losses of NO{sub 3} radicals can compete with NO{sub x} caused by OH radicals during day-time. (orig./KW)}
place = {Germany}
year = {1993}
month = {Apr}
}
title = {On the interaction of NO{sub 3} radicals with aqueous solutions: Estimation of the Henry coefficient and the mass accomodation coefficient; Zur Wechselwirkung von NO{sub 3}-Radikalen mit waessrigen Loesungen: Bestimmung des Henry- und des Massenakkommodationskoeffizienten}
author = {Thomas, K, Volz-Thomas, A, and Kley, D}
abstractNote = {The Henry coefficient of NO{sub 3} radicals, K{sub h}(NO{sub 3}), was studied in coiled denuder tubes of 2 mm diameter and variable length, e.g. 4-350 cm. The radicals were produced in a flow system by oxidation of NO with excess O{sub 3} at a temperature of 393 K. A small flow of pure H{sub 2}O was metered to the gas-flow and allowed to form a thin film on the denuder wall. Behind the denuder, gas and liquid were separated and the concentration of the dissolved NO{sub 3} was determined indirectly, after conversion to nitrate by reaction with Cl{sup -}-ions, which were added to the effluent of the denuder. The partial pressure of NO{sub 3} in the gas-phase behind the denuder was determined by quantitative conversion to nitrate in another denuder. The same experimental set-up was used to determine the mass accommodation coefficient of NO{sub 3} to an aqueous surface. There, a high Cl{sup -}-concentration (0.1 M) was used in the stripping solution to efficiently convert the dissolved NO{sub 3} to NO{sub 3-} and thus prevent phase-equilibrium to be reached. The mass accommodation coefficient was derived from the transmittance of the denuder as a function of length. The method requires the knowledge of the diffusion coefficient, which was determined in separate experiments conducted under the same conditions with HNO{sub 3}. The mass accommodation coefficient of NO{sub 3} was found to be {>=}2.5.10{sup -3}. Theoretical considerations and time-dependent box-model calculations show that even under favourable conditions, heterogeneous losses of NO{sub 3} are important for the budget of NO{sub x} only, if NO{sub x}-concentrations are below 0.5 ppb. At higher NO{sub x}-concentrations, the night-time losses proceed predominantly via N{sub 2}O{sub 5}. In the maritime boundary layer, night-time losses of NO{sub 3} radicals can compete with NO{sub x} caused by OH radicals during day-time. (orig./KW)}
place = {Germany}
year = {1993}
month = {Apr}
}