A Knudsen Cell Study of the Heterogeneous Reactivity of Nitric Acid on Oxide and Mineral Dust Particles

2001 ◽  
Vol 105 (27) ◽  
pp. 6609-6620 ◽  
Author(s):  
G. M. Underwood ◽  
P. Li ◽  
H. Al-Abadleh ◽  
V. H. Grassian
Keyword(s):  
Nitric Acid ◽  
Mineral Dust ◽  
Knudsen Cell ◽  
Dust Particles ◽  
Heterogeneous Reactivity ◽  
Cell Study

scholarly journals DRIFTS and Knudsen cell study of the heterogeneous reactivity of SO<sub>2</sub> and NO<sub>2</sub> on mineral dust

2003 ◽  
Vol 3 (6) ◽  
pp. 2043-2051 ◽  
Author(s):  
M. Ullerstam ◽  
M. S. Johnson ◽  
R. Vogt ◽  
E. Ljungström
Keyword(s):  
Gas Phase ◽  
Loss Rate ◽  
Mineral Dust ◽  
Knudsen Cell ◽  
Heterogeneous Oxidation ◽  
Heterogeneous Reactivity ◽  
Significant Difference ◽  
Phase Loss ◽  
Diffuse Reflectance Infrared ◽  
Cell Study

Abstract. The heterogeneous oxidation of SO2 by NO2 on mineral dust was studied using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and a Knudsen cell. This made it possible to characterise, kinetically, both the formation of sulfate and nitrate as surface products and the gas phase loss of the reactive species. The gas phase loss rate was determined to be first order in both SO2 and NO2. From the DRIFTS experiment the uptake coefficient, g, for the formation of sulfate was determined to be of the order of 10-10 using the BET area as the reactive surface area. No significant formation of sulfate was seen in the absence of NO2. The Knudsen cell study gave uptake coefficients of the order of 10-6 and 10-7 for SO2 and NO2 respectively. There was no significant difference in uptake when SO2 or NO2 were introduced individually compared to experiments in which SO2 and NO2 were present at the same time.

scholarly journals DRIFTS and Knudsen cell study of the heterogeneous reactivity of SO<sub>2</sub> and NO<sub>2</sub> on mineral dust

2003 ◽  
Vol 3 (4) ◽  
pp. 4069-4096
Author(s):  
M. Ullerstam ◽  
M. S. Johnson ◽  
R. Vogt ◽  
E. Ljungström
Keyword(s):  
Gas Phase ◽  
Loss Rate ◽  
Mineral Dust ◽  
Knudsen Cell ◽  
Heterogeneous Oxidation ◽  
Heterogeneous Reactivity ◽  
Significant Difference ◽  
Phase Loss ◽  
Diffuse Reflectance Infrared ◽  
Cell Study

Abstract. The heterogeneous oxidation of SO2 by NO2 on mineral dust was studied using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and a Knudsen cell. This made it possible to characterise, kinetically, both the formation of sulfate and nitrate as surface products and the gas phase loss of the reactive species. The gas phase loss rate was determined to be first order in both SO2 and NO2. From the DRIFTS experiment the uptake coefficient, γ, for the formation of sulfate was determined to be of the order of 10−10 using the BET area as the reactive surface area. No significant formation of sulfate was seen in the absence of  NO2. The Knudsen cell study gave uptake coefficients of the order of 10−6 and 10-7 for SO2 and NO2, respectively. There was no significant difference in uptake when SO2 or NO2 were introduced individually compared to experiments in which SO2 and NO2 were present at the same time.

Heterogeneous Uptake of Gaseous Nitric Acid on Dolomite (CaMg(CO3)2) and Calcite (CaCO3) Particles:  A Knudsen Cell Study Using Multiple, Single, and Fractional Particle Layers

2005 ◽  
Vol 109 (31) ◽  
pp. 6901-6911 ◽  
Author(s):  
Elizabeth R. Johnson ◽  
Joanna Sciegienka ◽  
Sofia Carlos-Cuellar ◽  
Vicki H. Grassian
Keyword(s):  
Nitric Acid ◽  
Knudsen Cell ◽  
Cell Study

Kinetics of the heterogeneous reaction of nitric acid with mineral dust particles: an aerosol flowtube study

2009 ◽  
Vol 11 (36) ◽  
pp. 7921 ◽  
Author(s):  
A. Vlasenko ◽  
T. Huthwelker ◽  
H. W. Gäggeler ◽  
M. Ammann
Keyword(s):  
Nitric Acid ◽  
Mineral Dust ◽  
Heterogeneous Reaction ◽  
Dust Particles ◽  
Kinetics Of

scholarly journals Effect of humidity on nitric acid uptake to mineral dust aerosol particles

2005 ◽  
Vol 5 (6) ◽  
pp. 11821-11860 ◽  
Author(s):  
A. Vlasenko ◽  
S. Sjogren ◽  
E. Weingartner ◽  
K. Stemmler ◽  
H. W. Gäggeler ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Reaction Time ◽  
Surface Area ◽  
Flow Reactor ◽  
Mineral Dust ◽  
Water Soluble ◽  
Dust Particles ◽  
Acid Uptake ◽  
Laboratory Observation ◽  
Powder Samples

Abstract. This study presents the first laboratory observation of HNO3 uptake by airborne mineral dust particles. The model aerosols were generated by dry dispersion of Arizona Test Dust (ATD), SiO2, and by nebulizing a saturated solution of calcium carbonate. The uptake of 13N-labelled gaseous nitric acid was observed in a flow reactor on the 0.2–2 s reaction time scale at room temperature and atmospheric pressure. The amount of reacted nitric acid was found to be a linear function of aerosol surface area. SiO2 particles did not show any significant uptake, while the CaCO3 aerosol was found to be more reactive than the ATD. Due to the smaller uncertainty associated with the reactive surface area in the case of suspended particles as compared to bulk powder samples, we believe that we provide an improved estimate of the uptake kinetics of HNO3 to mineral dust. The uptake coefficient averaged over the first 2 s of reaction time at a concentration of 1012 molecules cm−3 was found to increase with increasing relative humidity, from 0.022±0.007 at 12% RH to 0.113±0.017 at 73% RH , scaling along a water adsorption isotherm. The processing of the dust at 85% RH leads to a water soluble coating on the particles and enhances their hygroscopicity.

scholarly journals Effect of humidity on nitric acid uptake to mineral dust aerosol particles

2006 ◽  
Vol 6 (8) ◽  
pp. 2147-2160 ◽  
Author(s):  
A. Vlasenko ◽  
S. Sjogren ◽  
E. Weingartner ◽  
K. Stemmler ◽  
H. W. Gäggeler ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Reaction Time ◽  
Surface Area ◽  
Flow Reactor ◽  
Mineral Dust ◽  
Water Soluble ◽  
Dust Particles ◽  
Acid Uptake ◽  
Uptake Mechanism ◽  
Laboratory Observation

Abstract. This study presents the first laboratory observation of HNO3 uptake by airborne mineral dust particles. The model aerosols were generated by dry dispersion of Arizona Test Dust (ATD), SiO2, and by nebulizing a saturated solution of calcium carbonate. The uptake of 13N-labeled gaseous nitric acid was observed in a flow reactor on the 0.2–2 s reaction time scale at room temperature and atmospheric pressure. The amount of nitric acid appearing in the aerosol phase at the end of the flow tube was found to be a linear function of the aerosol surface area. SiO2 particles did not show any significant uptake, while the CaCO3 aerosol was found to be more reactive than ATD. Due to the smaller uncertainty associated with the reactive surface area in the case of suspended particles as compared to bulk powder samples, we believe that we provide an improved estimate of the rate of uptake of HNO3 to mineral dust. The fact that the rate of uptake was smaller at a concentration of 1012 than at 1011 was indicative of a complex uptake mechanism. The uptake coefficient averaged over the first 2 s of reaction time at a concentration of 1012 molecules cm-3 was found to increase with increasing relative humidity, from 0.022±0.007 at 12% RH to 0.113±0.017 at 73% RH , which was attributed to an increasing degree of solvation of the more basic minerals. The extended processing of the dust by higher concentrations of HNO3 at 85% RH led to a water soluble coating on the particles and enhanced their hygroscopicity.

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