The kinetics of the heterogeneous reaction of BrONO2 with solid alkali halides at ambient temperature. A comparison with the interaction of ClONO2 on NaCl and KBr

Aguzzi, Arnaud; Rossi, Michel J.

doi:10.1039/a904611i

Cited by 22 publications

(60 citation statements)

References 25 publications

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“…The heterogeneous reactions of BrONO 2 with solid alkali halides have also been investigated in a Teflon-coated Knudsen flow reactor at ambient temperature (Aguzzi and Rossi, 1999). For solid NaCl substrates, BrCl, Br 2 and HCl were observed as products while for KBr both Br 2 and HBr were detected.…”

Section: Introductionmentioning

confidence: 99%

“…The heterogeneous reactions of ClONO 2 with solid NaCl and KBr have already been studied in a fast flow reactor (Timonen et al, 1994) and a Knudsen cell (Aguzzi and Rossi, 1999;Caloz et al, 1996;Gebel and Finlayson-Pitts, 2001;Wingenter et al, 1996) and the primary reaction products on NaCl were HOCl and Cl 2 while BrCl was observed on KBr.…”

Section: Introductionmentioning

confidence: 99%

“…All these experiments were conducted over different solid substrates corresponding to powders (Timonen et al, 1994;Caloz et al, 1996;Gebel et al, 2001), spray deposited films, grains of various sizes and also single crystals (Caloz et al, 1996 ;Aguzzi and Rossi, 1999). Most of these experiments were also performed at low pressure (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Uptake study of ClONO2 and BrONO2 by Halide containing droplets

Deiber

George²,

Calvé

et al. 2004

Atmos. Chem. Phys.

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Abstract. The uptake kinetics of gaseous ClONO 2 and BrONO 2 on aqueous surfaces were measured, as a function of temperature and liquid composition (pure water and NaCl or NaBr containing solutions) using the droplet train technique coupled to a mass spectrometer. The uptake kinetics are driven by the reactivity of these gases and, for both compounds, the uptake rates on pure water or on NaCl solutions (0.1 M) are comparable. The uptake coefficient γ of ClONO 2 does not depend on the temperature while that of BrONO 2 increases slightly when the temperature is raised from 272 to 280 K. For ClONO 2 and BrONO 2 , the uptake rates increase on NaBr-doped droplets, enabling the estimation of the mass accommodation coefficient α. The corresponding values for α are 0.108±0.033 for ClONO 2 and 0.063±0.021 for BrONO 2 where the statistical errors correspond to ±2σ .The reactions of ClONO 2 and BrONO 2 on NaCl solutions lead respectively to the formation of Cl 2 and BrCl. The uptake of ClONO 2 on NaBr solutions generates BrCl as primary product, which in turn can react with NaBr to produce Br 2 . As expected, the only product of BrONO 2 reaction on NaBr solution is Br 2 .

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Uptake study of ClONO2 and BrONO2 by Halide containing droplets

Deiber

George²,

Calvé

et al. 2004

Atmos. Chem. Phys.

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“…Only when the heterogeneous reactions (4) and (5) of HOBr on ice and snow are included does the simulation of tropospheric ozone destruction agree with field measurements through halogen activation [15]. However, only few data are available for HOCl heterogeneous reactions on marine aerosol and sea ice in comparison to uptake experiments of HOBr or HOCl performed on solid substrates [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

“…The mass balance from Figure 1a between Cl 2 O uptake on frozen KCl solution and product formation may be expressed as follows: 7.3!10 16 Cl 2 O molecules were taken up against production of 8.4!10 16 HOCl and 4.9!10 16 Cl 2 molecules produced (see Table 5). After uptake, the frozen solution was annealed at 240 K resulting in the desorption of 1.6!10 15 Cl 2 O corresponding to approximately 2% of the total Cl 2 O initially taken up.…”

Section: Mass Balance For Pure CL 2 O Uptakementioning

confidence: 99%

Heterogeneous Chemistry of Cl₂O and HOCl on Frozen Natural Sea Salt, Recrystallized Sea Salt, KCl and NaCl Solutions at 200 and 215 K

Pratte

Rossi²

2010

Zeitschrift Für Physikalische Chemie

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The HOCl heterogeneous reaction on frozen natural (NSS) and recrystallized (RSS) sea salt, KCl and NaCl solutions was studied using a low pressure flow reactor in order to measure the uptake coefficient γ and products of reaction. The HOCl sample used in these experiments always contained up to 25% Cl2O which was also studied separately as a pure gas in order to understand the heterogeneous chemistry of both gases. By performing HOCl uptake on frozen NSS solution at 200 K and a gas-phase residence time of (1.6±0.6) s we obtained a steady state uptake coefficient γHOCl on NSS = (2.5±0.7)×10-3 and γCl2O on NSS = (2.8±0.8)×10-3. On frozen KCl solution at 200 K we obtain γHOCl on KCl = (2.8±1.3)×10-3, identical to NSS, and γCl2O on KCl = (4.6±0.8)×10-4. The main product formed during the uptake on frozen NSS solution is Cl2 which is sustained for at least one hour. In contrast, only a transient Cl2 flow (pulse) decreasing on the time scale of 100 s was observed on frozen KCl (NaCl) solution. 25±10 % of the HOCl taken up on all chloride-containing frozen substrates at 200 K react to produce Cl2 at high HOCl concentration (4.5×1011 molecule cm-3) and at a residence time of 1.6 s in comparison with twice that for Cl2O. For smaller concentrations such as [HOCl] = 3.7×1010 molecule cm-3 and/or a shorter residence time (0.137±0.004s), HOCl uptake did not generate Cl2 in contrast to Cl2O. A single Br2 burst event was monitored when a Cl2O or HOCl/Cl2O mixture is taken up on fresh frozen NSS solution during the first uptake at 200 K. Further Cl2O or HOCl/Cl2O uptake on the same sample, even after annealing at 240 K does not show an additional Br2 pulse. This Br2 release may be significant in the autocatalytic ozone destruction mechanism in the troposphere during polar sunrise. Some of the atmospheric implications of the present results are highlighted with emphasis on the preequilibrium Cl2O(ads) + H2O(ice) ↔ 2 HOCl(ads) between adsorbed HOCl and Cl2O, with the latter being the gateway to reactive uptake of HOCl at low temperatures.

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Observations of bromine explosions in smog chamber experiments above a model salt pan

Buxmann

Balzer

Bleicher

et al. 2012

Int J of Chemical Kinetics

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Reactive halogen species (RHS), such as Cl, Br, or BrO, can have significant influence on chemical processes in the troposphere, including the destruction of ozone, change in the chemical balance of OH and HO2, and increased deposition of toxic compounds (like mercury), with potential consequences for the global climate. Previous studies have shown that salt lakes can provide a significant source for gaseous RHS. Environmental conditions, such as salt composition, relative humidity (RH), pH, and temperature (T), might have a strong influence on reactive bromine levels. In our laboratory experiments, NaCl salt containing 0.33% NaBr by weight was exposed to simulated sunlight in a Teflon smog chamber under various conditions of RH and ozone concentrations. BrO levels were observed by a differential optical absorption spectrometer in combination with a multireflection cell (White cell). The concentrations of OH and Cl radicals were quantified by the radical clock method. We present the first direct observation of BrO from the “bromine explosion” (autocatalytic release of reactive bromine from salt surfaces—key to ozone destruction) in the laboratory above a simulated salt pan. The maximum BrO mixing ratio of 6419 ± 71 ppt at 60% RH was observed to be one order of magnitude higher than at 37% RH and 2% RH. The release of RHS from the salt pan is possibly controlled by the thickness of the quasi‐liquid layer, covering the reactive surface of the halide crystals, as the layer thickness strongly depends on RH. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 312–326, 2012

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The kinetics of the heterogeneous reaction of BrONO2 with solid alkali halides at ambient temperature. A comparison with the interaction of ClONO2 on NaCl and KBr

Cited by 22 publications

References 25 publications

Uptake study of ClONO<sub>2</sub> and BrONO<sub>2</sub> by Halide containing droplets

Uptake study of ClONO<sub>2</sub> and BrONO<sub>2</sub> by Halide containing droplets

Heterogeneous Chemistry of Cl₂O and HOCl on Frozen Natural Sea Salt, Recrystallized Sea Salt, KCl and NaCl Solutions at 200 and 215 K

Observations of bromine explosions in smog chamber experiments above a model salt pan

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The kinetics of the heterogeneous reaction of BrONO2 with solid alkali halides at ambient temperature. A comparison with the interaction of ClONO2 on NaCl and KBr

Cited by 22 publications

References 25 publications

Uptake study of ClONO&lt;sub&gt;2&lt;/sub&gt; and BrONO&lt;sub&gt;2&lt;/sub&gt; by Halide containing droplets

Uptake study of ClONO&lt;sub&gt;2&lt;/sub&gt; and BrONO&lt;sub&gt;2&lt;/sub&gt; by Halide containing droplets

Heterogeneous Chemistry of Cl2O and HOCl on Frozen Natural Sea Salt, Recrystallized Sea Salt, KCl and NaCl Solutions at 200 and 215 K

Observations of bromine explosions in smog chamber experiments above a model salt pan

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Uptake study of ClONO<sub>2</sub> and BrONO<sub>2</sub> by Halide containing droplets

Uptake study of ClONO<sub>2</sub> and BrONO<sub>2</sub> by Halide containing droplets

Heterogeneous Chemistry of Cl₂O and HOCl on Frozen Natural Sea Salt, Recrystallized Sea Salt, KCl and NaCl Solutions at 200 and 215 K