Time-dependent uptake of NO3 by sea salt     

Vladislav V. Zelenov  Elena V. Aparina  Andrey V. Ivanov 《Journal of Atmospheric Chemistry》2014,71(1):33-53

Using a coated-insert flow tube reactor coupled to a low-energy electron-impact mass spectrometer with molecular beam sampling, we studied uptake of NO₃ by sea salt at room temperature and [NO₃]?=?8?10¹¹???4?10¹³ molecule cm^?3. The radical uptake coefficient γ(t) is time dependent: its initial value (γ _ini) decreases exponentially with the characteristic time (τ) to its steady-state value (γ _ss) at given [NO₃]. The parameters γ _ini, γ _ss and τ depend on [NO₃], whereas γ _ss is water vapor independent at [H₂O]?=?8?10¹²???1.6?10¹⁵ molecule cm^?3 and RH ≤ 0.5 %. HCl and NO₂ are uptake products detected in the gas phase. We used these findings to estimate γ values under tropospheric conditions for urban coastal and remote marine environments: at high NO₃ (~90 ppt), the time dependence becomes important, and the γ value averaged over the aerosol lifetime is 4?10^?3; at low NO₃ (~1 ppt), the radical uptake is time independent and proceeds faster with γ _ini?=?8?10^?3  相似文献   

The Mechanism of Reactive NO3 Uptake on Dry NaX (X=Cl, Br)     

Mikhail Yu. Gershenzon  Sergeid. Il'in  Nikolai G. Fedotov  Yulii M. Gershenzon  Elena V. Aparina  Vladislav V. Zelenov 《Journal of Atmospheric Chemistry》1999,34(1):119-135

A simple kinetic mechanism of nitrate radicals uptake on dry sea-salt NaCl, NaBr surfaces is proposed. The mechanism includes adsorption/desorption equilibrium and unimolecular decomposition of the adsorbed complex: NO₃(g) + NaX(s) (NO₃-NaX)(s); (NO₃-NaX)(s) NaNO₃ + X(s) Two techniques were used: the matrix isolation ESR and mass spectrometry. The uptake coefficient () is found to be dependent on exposure time of salt to NO₃ for raw coating. The initial (t0) is higher than the observable steady-state _obs. At room temperature _obs is independent of [NO₃] at low [NO₃] = 3 × 10⁹ - 10¹¹ cm^-3, but it is inversely proportional to [NO₃] at concentrations higher than 10¹² cm^-3. At temperatures above 100 °C, _obs becomes independent of [NO₃] in a wider range of [NO₃]. An increased number of dislocations is supposed to exist in the case of raw coating. Due to a wide spread of the surface sites binding energy with the ionic lattice near dislocations, the part of surface complexes has lower binding energy and "burns" more rapidly. That burning determines the transition from (t0) down to _obs.The kinetic parameters and elementary rate coefficients are obtained. The recommended for low atmospheric NO₃ concentration are in the range of 0.002 ± 0.04 for NaCl and 0.1-0.3 for NaBr depending on a mechanism of the (t) relaxation.  相似文献   

Study of the State and Variability of the Northwestern Japan Sea in the Autumn–Winter Period on Cruise 62 of the R/V Akademik Oparin     

Lobanov  V. B.  Sergeev  A. F.  Maryina  E. N.  Prushkovskaya  I. A.  Tishchenko  P. Y.  Kalinchuk  V. V.  Koltunov  A. M.  Makseev  D. S.  Sagalaev  S. G.  Yurikova  D. A.  Akulova  E. A.  Aparina  K. A.  Zagoruyko  O. I.  Zverev  S. A.  Kraynikov  G. A.  Kukla  S. P.  Leusov  A. E.  Lukyanova  N. B.  Ryumina  A. A.  Semkin  P. Y.  Shvetsova  M. G.  Shkirnikova  E. M.  Yurikova  E. A.  Yurtsev  A. Y.  Yakimov  T. S. 《Oceanology》2021,61(5):742-744

Oceanology - The results of research carried out on cruise 62 of the R/V Akademik Oparin from December 14 to 29, 2020 continued monitoring of the interannual variability of the Japan Sea water...  相似文献