Uptake of Gas-Phase Ammonia. 1. Uptake by Aqueous Surfaces as a Function of pH

Qiu, Shi; Davidovits, P.; Jayne, J. T.; Worsnop, D. R.; Kolb, C. E.

doi:10.1021/jp991696p

Cited by 117 publications

(227 citation statements)

References 43 publications

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“…170 However, ATR-FTIR studies of SO 2 uptake into thin water films on an infrared-transmitting crystal, interpreted with the aid of ab initio calculations, failed to find evidence for an interface complex of SO 2 with water. 171 It may be that the surface complex was present at concentrations below the detection limit of 4 Â 10 14 cm À2 or that in this case, the complex is an ion-water cluster, 168,172,173 for which the detection limits were higher, rather than a complex with the unionized gas molecule.…”

Section: View Article Onlinementioning

confidence: 99%

The heterogeneous hydrolysis of NO2 in laboratory systems and in outdoor and indoor atmospheres: An integrated mechanism

Finlayson-Pitts

Wingen

Sumner

et al. 2002

Phys. Chem. Chem. Phys.

621

767

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The heterogeneous reaction of NO 2 with water on the surface of laboratory systems has been known for decades to generate HONO, a major source of OH that drives the formation of ozone and other air pollutants in urban areas and possibly in snowpacks. Previous studies have shown that the reaction is first order in NO 2 and in water vapor, and the formation of a complex between NO 2 and water at the air-water interface has been hypothesized as being the key step in the mechanism. We report data from long path FTIR studies in borosilicate glass reaction chambers of the loss of gaseous NO 2 and the formation of the products HONO, NO and N 2 O. Further FTIR studies were carried out to measure species generated on the surface during the reaction, including HNO 3 , N 2 O 4 and NO 2 + . We propose a new reaction mechanism in which we hypothesize that the symmetric form of the NO 2 dimer, N 2 O 4 , is taken up on the surface and isomerizes to the asymmetric form, ONONO 2 . The latter autoionizes to NO + NO 3 À , and it is this intermediate that reacts with water to generate HONO and surface-adsorbed HNO 3 . Nitric oxide is then generated by secondary reactions of HONO on the highly acidic surface. This new mechanism is discussed in the context of our experimental data and those of previous studies, as well as the chemistry of such intermediates as NO + and NO 2 + that is known to occur in solution. Implications for the formation of HONO both outdoors and indoors in real and simulated polluted atmospheres, as well as on airborne particles and in snowpacks, are discussed. A key aspect of this chemistry is that in the atmospheric boundary layer where human exposure occurs and many measurements of HONO and related atmospheric constituents such as ozone are made, a major substrate for this heterogeneous chemistry is the surface of buildings, roads, soils, vegetation and other materials. This area of reactions in thin films on surfaces (SURFACE ¼ Surfaces, Urban and Remote: Films As a Chemical Environment) has received relatively little attention compared to reactions in the gas and liquid phases, but in fact may be quite important in the chemistry of the boundary layer in urban areas.

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Section: View Article Onlinementioning

confidence: 99%

The heterogeneous hydrolysis of NO2 in laboratory systems and in outdoor and indoor atmospheres: An integrated mechanism

Finlayson-Pitts

Wingen

Sumner

et al. 2002

Phys. Chem. Chem. Phys.

621

767

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“…To account for discrepancies between the Gibbs free energy calculated from the temperature dependence of the accommodation coefficients of a series of alcohols and the Gibbs free energy of solvation calculated from the corresponding thermodynamic changes of enthalpy and entropy, Davidovits and co-workers [23,24] have proposed a new model for the uptake of gas molecules by liquids. The model uses the concept that the interface is a narrow region of a dense gas-like state within which nucleation is constantly occurring.…”

Section: Mechanism Of Ammonia Dissolution In Watermentioning

confidence: 99%

Fate of ammonia in the atmosphere?a review for applicability to hazardous releases

Renard

Calidonna

Henley³

2004

Journal of Hazardous Materials

139

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“…As discussed in Shi et al 18 and references therein, in the absence of surface reactions, γ meas is expressed as…”

Section: Modeling Gas Uptakementioning

confidence: 99%

Uptake of Gas-Phase SO₂, H₂S, and CO₂ by Aqueous Solutions

Boniface¹,

Qiu²,

Li³

et al. 2000

J. Phys. Chem. A

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The uptake of gas-phase SO 2 , H 2 S, and CO 2 by aqueous solutions was studied as a function of pH and temperature using droplet train flow reactor and bubble train reactor apparatuses. All three atmospheric species react with H 2 O and OH -, acidifying aqueous solutions. Studies yielded the reaction rates of SO 2 , H 2 S, and CO 2 with OH -and the mass accommodation coefficient (R) of SO 2 on water as a function of temperature. The second-order aqueous-phase rate coefficients at 291 K for SO 2 , H 2 S and CO 2 reaction with OH -are (1.1 ( 0.2) × 10 10 , (1.7 ( 0.2) × 10 9 , and (4.0 ( 0.7) × 10 3 M -1 s -1 , respectively. As far as we can determine, the rate coefficients for SO 2 and H 2 S have been determined here for the first time. At 291 K, for SO 2 , R ) 0.175 ( 0.015, and as in previous studies, the temperature dependence of R is well represented by the relationship R /(1 -R) ) exp(-∆G obs /RT) with ∆H obs ) -7.6 ( 0.6 kcal mol -1 and ∆S obs ) -29.2 ( 2.1 cal mol -1 K -1 . IntroductionIn this work, we describe uptake studies of gas-phase SO 2 , H 2 S, and CO 2 by aqueous solutions as a function of pH and temperature. These three atmospheric species exhibit similar chemical behaviors that contribute to the acidification of aqueous media in the atmosphere. Sulfur dioxide oxidation is responsible for about 90% of atmospheric H 2 SO 4 , and an estimated 50% of this oxidation occurs via heterogeneous reactions. 1 Hydrogen sulfide is a major biogenic reduced sulfur species, emitted into the atmosphere by vegetation, soils, and marine waters, 2 that is oxidized by the OH radical in the gas phase to produce SO 2 . 3 H 2 S may also be important to O 3 chemistry, as in the aqueous phase, H 2 S dissociates readily to HS -, which, in turn, reacts rapidly with O 3 . 4 Of the three gas-phase species, CO 2 is the least reactive but perhaps the most atmospherically important. Because of its high atmospheric abundance (∼370 ppm) and its infrared absorption properties, CO 2 plays an important role in the global warming process.The pH-dependent reactions of SO 2 and CO 2 in aqueous solution are (R ) SO 2 or CO 2 )The pH-dependent reactions of H 2 S are Here, k 1 is the pseudo-first-order reaction-rate coefficient of the species with H 2 O, and k 2 is the second-order reaction-rate coefficient of the species with OH -. As the current study makes evident, the forward reaction rates for SO 2 , H 2 S, and CO 2 with OH -vary over nearly 6 orders of magnitude. The uptake coefficients vary over a similar range. Two complementary apparatuses were used to span this range of uptake coefficients: a droplet train flow reactor apparatus and a horizontal bubble train reactor apparatus. The uptake measurements yielded rate coefficients for the reaction of SO 2 , H 2 S, and CO 2 with OH -, and the mass accommodation coefficient for SO 2 on water as a function of temperature.In several previous uptake studies, the measured uptake was larger than predicted by bulk-phase parameters. Such enhanced uptake was observed among others in the follow...

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Uptake of Gas-Phase Ammonia. 1. Uptake by Aqueous Surfaces as a Function of pH

Cited by 117 publications

References 43 publications

The heterogeneous hydrolysis of NO2 in laboratory systems and in outdoor and indoor atmospheres: An integrated mechanism

The heterogeneous hydrolysis of NO2 in laboratory systems and in outdoor and indoor atmospheres: An integrated mechanism

Fate of ammonia in the atmosphere?a review for applicability to hazardous releases

Uptake of Gas-Phase SO₂, H₂S, and CO₂ by Aqueous Solutions

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Uptake of Gas-Phase Ammonia. 1. Uptake by Aqueous Surfaces as a Function of pH

Cited by 117 publications

References 43 publications

The heterogeneous hydrolysis of NO2 in laboratory systems and in outdoor and indoor atmospheres: An integrated mechanism

The heterogeneous hydrolysis of NO2 in laboratory systems and in outdoor and indoor atmospheres: An integrated mechanism

Fate of ammonia in the atmosphere?a review for applicability to hazardous releases

Uptake of Gas-Phase SO2, H2S, and CO2 by Aqueous Solutions

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Product

Resources

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Uptake of Gas-Phase SO₂, H₂S, and CO₂ by Aqueous Solutions