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

Kinetics and mechanism of the heterogeneous reaction of N2O5 with mineral dust particles

2012 ◽  
Vol 14 (24) ◽  
pp. 8551 ◽  
Author(s):  
M. J. Tang ◽  
J. Thieser ◽  
G. Schuster ◽  
J. N. Crowley
Keyword(s):  
Mineral Dust ◽  
Heterogeneous Reaction ◽  
Kinetics And Mechanism ◽  
Dust Particles

scholarly journals Direct observations of the atmospheric processing of Asian mineral dust

2007 ◽  
Vol 7 (5) ◽  
pp. 1213-1236 ◽  
Author(s):  
R. C. Sullivan ◽  
S. A. Guazzotti ◽  
D. A. Sodeman ◽  
K. A. Prather
Keyword(s):  
Mineral Dust ◽  
Heterogeneous Reaction ◽  
Field Studies ◽  
Dust Particles ◽  
Reaction Products ◽  
Transport Pathway ◽  
Air Masses ◽  
Atmospheric Processing ◽  
Acid Reaction ◽  
The Individual

Abstract. The accumulation of secondary acids and ammonium on individual mineral dust particles during ACE-Asia has been measured with an online single-particle mass spectrometer, the ATOFMS. Changes in the amounts of sulphate, nitrate, and chloride mixed with dust particles correlate with air masses from different source regions. The uptake of secondary acids depended on the individual dust particle mineralogy; high amounts of nitrate accumulated on calcium-rich dust while high amounts of sulphate accumulated on aluminosilicate-rich dust. Oxidation of S(IV) to S(VI) by iron in the aluminosilicate dust is a possible explanation for this enrichment of sulphate, which has important consequences for the fertilization of remote oceans by soluble iron. This study shows the segregation of sulphate from nitrate and chloride in individual aged dust particles for the first time. A transport and aging timeline provides an explanation for the observed segregation. Our data suggests that sulphate became mixed with the dust first. This implies that the transport pathway is more important than the reaction kinetics in determining which species accumulate on mineral dust. Early in the study, dust particles in volcanically influenced air masses were mixed predominately with sulphate. Dust mixed with chloride then dominated over sulphate and nitrate when a major dust front reached the R. V. Ronald Brown. We hypothesize that the rapid increase in chloride on dust was due to mixing with HCl(g) released from acidified sea salt particles induced by heterogeneous reaction with volcanic SO2(g), prior to the arrival of the dust front. The amount of ammonium mixed with dust correlated strongly with the total amount of secondary acid reaction products in the dust. Submicron dust and ammonium sulphate were internally mixed, contrary to frequent reports that they exist as external mixtures. The size distribution of the mixing state of dust with these secondary species validates previous mechanisms of the atmospheric processing of dust and generally agrees with simulated aerosol chemistry from the STEM-2K3 model. This series of novel results has important implications for improving the treatment of dust in global chemistry models and highlights a number of key processes that merit further investigation through laboratory and field studies.

scholarly journals Measurements of cloud condensation nuclei activity and droplet activation kinetics of fresh unprocessed regional dust samples and minerals

2011 ◽  
Vol 11 (7) ◽  
pp. 3527-3541 ◽  
Author(s):  
P. Kumar ◽  
I. N. Sokolik ◽  
A. Nenes
Keyword(s):  
Ammonium Sulfate ◽  
Mineral Dust ◽  
Cloud Condensation Nuclei ◽  
Dust Particles ◽  
Droplet Growth ◽  
Condensation Nuclei ◽  
Activation Kinetics ◽  
Droplet Activation ◽  
Kinetics Of ◽  
Ccn Activity

Abstract. This study reports laboratory measurements of cloud condensation nuclei (CCN) activity and droplet activation kinetics of aerosols dry generated from clays, calcite, quartz, and desert soil samples from Northern Africa, East Asia/China, and Northern America. Based on the observed dependence of critical supersaturation, sc, with particle dry diameter, Ddry, we found that FHH (Frenkel, Halsey and Hill) adsorption activation theory is a far more suitable framework for describing fresh dust CCN activity than Köhler theory. One set of FHH parameters (AFHH ∼ 2.25 ± 0.75, BFHH ∼ 1.20 ± 0.10) can adequately reproduce the measured CCN activity for all species considered, and also explains the large range of hygroscopicities reported in the literature. Based on a threshold droplet growth analysis, mineral dust aerosols were found to display retarded activation kinetics compared to ammonium sulfate. Comprehensive simulations of mineral dust activation and growth in the CCN instrument suggest that this retardation is equivalent to a reduction of the water vapor uptake coefficient (relative to that for calibration ammonium sulfate aerosol) by 30–80%. These results suggest that dust particles do not require deliquescent material to act as CCN in the atmosphere.

scholarly journals Measurements of cloud condensation nuclei activity and droplet activation kinetics of fresh unprocessed regional dust samples and minerals

2010 ◽  
Vol 10 (12) ◽  
pp. 31039-31081 ◽  
Author(s):  
P. Kumar ◽  
I. N. Sokolik ◽  
A. Nenes
Keyword(s):  
Ammonium Sulfate ◽  
Mineral Dust ◽  
Cloud Condensation Nuclei ◽  
Dust Particles ◽  
Droplet Growth ◽  
Condensation Nuclei ◽  
Activation Kinetics ◽  
Droplet Activation ◽  
Kinetics Of ◽  
Ccn Activity

Abstract. This study reports laboratory measurements of cloud condensation nuclei (CCN) activity and droplet activation kinetics of aerosols dry-generated from clays, calcite, quartz, and desert soil samples from Northern Africa, East Asia/China, and Northern America. Based on the observed dependence of critical supersaturation, sc, with particle dry diameter, Ddry, we find that FHH adsorption activation theory is a far more suitable framework for describing fresh dust CCN activity than Köhler theory. One set of FHH parameters (AFFH ~ 2.25 ± 0.75, BFFH ~ 1.20 ± 0.10) can adequately reproduce the measured CCN activity for all species considered, and also explains the large range of hygroscopicities reported in the literature. Based on threshold droplet growth analysis, mineral dust aerosols were found to display retarded activation kinetics compared to ammonium sulfate. Comprehensive simulations of mineral dust activation and growth in the CCN instrument suggest that this retardation is equivalent to a reduction of the water vapor uptake coefficient (relative to that for calibration ammonium sulfate aerosol) by 30–80%. These results suggest that dust particles do not require deliquescent material to act as CCN in the atmosphere.

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.

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
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