首页 | 本学科首页   官方微博 | 高级检索  
     检索      


On the Exchange of NO3 Radicals with Aqueous Solutions: Solubility and Sticking Coefficient
Authors:Karin Thomas  Andreas Volz-Thomas  Djuro Mihelcic  Herman G J Smit  Dieter Kley
Institution:(1) Institut für Chemie und Dynamik der Geosphäre 2, Chemie der Belasteten Atmosphäre Forschungszentrum Jülich, PO Box 1913, D-52425 Jülich, Germany
Abstract:The exchange of NO3 radicals with the aqueous-phase was investigated at room temperature (293 K) in a series of wetted denuders. From these experiments, the uptake coefficient of NO3 was determined on 0.1 M NaCl solutions and was found to be gamma(NO3) ge 2 × 10-3 in good agreement with recent studies. The Henry coefficient of NO3 was estimated to be KH(NO3) = 1.8 M · atm-1, with a (2sgr) uncertainty of ±3 M · atm-1. From the upper limit for the Henry coefficient (KH = 5 M · atm-1) and available thermodynamic data, the redox potential of dissolved NO3/NO 3 is estimated to be in the range of 2.3 to 2.5 V. This range is at the lower boundary of earlier estimates. The results are discussed in the light of a recent publication. Based on our data and a model of the transport and chemistry in the liquid film, an upper limit is derived for the product of the Henry coefficient KH and the rate coefficient k 10 of the potential reaction NO3 + H2O rarr HNO3 + OH. For KH = 0.6 M · atm-1, we find k 10 < 0.05 s-1 · atm-1, i.e., about 100 times smaller than what was suggested by Rudich and co-workers. Because of its small solubility, heterogeneous removal of NO3 is only important under conditions where the dissolved NO3 is removed quickly from equilibrium, for example by reactions with Cl or HSO 3 ions in the liquid-phase. Otherwise, heterogenous removal should mainly proceed via N2O5.
Keywords:nitrate radical  solubility  sticking coefficient  redox potential  heterogeneous removal
本文献已被 SpringerLink 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号