Heterogeneous reactions of sulfur dioxide with carbonaceous particles

Baldwin, Alan C.

doi:10.1002/kin.550140307

Cited by 24 publications

(9 citation statements)

References 10 publications

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“…Using the reaction rate quoted above, this implies an SO 2 removal rate due to heterogeneous reaction on black carbon in the smoke plume from the Kuwait oil fires of ~ 0.1% h '1. As discussed byBaldwin [1982], most measurements of SO 2 oxidation on black carbon indicate that the surface becomes saturated when 1 was 26.5 gg m '3. If 30% of this sulfate was due to heterogeneous reaction with black carbon, this would imply that the black carbon was able to take up at least 90 mg of SO 2 per gram of black carbon, which is more than 10 times the capacity measured by Baldwin.…”

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confidence: 90%

Heterogeneous chemistry in the smoke plume from the 1991 Kuwait oil fires

Herring¹,

Ferek²

1996

J. Geophys. Res.

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During late spring of 1991, airborne measurements in the smoke plume from the Kuwait oil fires indicated that SO2 was removed from the gas phase at rates of-6 to 8% h -1 and that NOx was removed at rates of ~ 7 to 23 % h -1. Photochemical calculations indicate that homogeneous chemical reactions were responsible for only a small fraction of this removal. Also, indirect evidence suggests that heterogeneous removal of SO2 on black carbon (or soot) and salt aerosols produced by the fires was relatively slow. The highest rates of SO2 and NOx removal were associated with high concentrations of atmospheric soil dust. This was likely due to heterogeneous oxidation of the SO2 and NOx on the surfaces of soil dust particles. The removal of SO2 and NOx on soil dust was probably accelerated by the alkaline nature of the dust. Heterogeneous reactions on soil dust particles proceeded more rapidly in regions of dispersed smoke than in the core of the plume; this was probably due to the depletion of the available surface area of the soil dust in regions of dense smoke. On the basis of smoke samples collected during the experiment we estimate that the quasi-second-order reaction rate for SO2 is (9 _+ 4) x 10 -8 (gg soil dust m-3) -• s -•. For a soil dust concentration of 200 gg m -3 this implies a removal rate for SO2 on soil dust of 6.5% h -•. 14,451 14,452 HERRING ET AL.: CHEMISTRY IN SMOKE FROM KUWAIT OIL FIRES using a radiative transfer model to calculate photolysis rates.Although we consider a wide variety of photochemical and gas phase processes, the main goal of this study is to understand the role of heterogeneous chemistry in the evolution of the plume. Specifically, we investigate four different mechanisms for the removal of SO 2 and NOx: homogeneous gas phase oxidation followed by condensation, heterogeneous reactions on black carbon combustion aerosols, reactions with NaC1 particles (which originated from the evaporation of oil field brines), and reactions with alkaline soil dust (from the background air). Airborne InstrumentationThe instrumentation aboard the Convair C131-A aircraft has been described by Hobbs et al. [1991], which can be consulted for details concerning the meteorological and microphysical instrumentation on the aircraft. Here we describe the system for making continuous and discrete measurements of gas phase constituents of the smoke plume.Two inlets on the aircraft are used for gas phase chemical sampling. One was connected to a manifold from which several continuous analyzers operated. Sulfur dioxide concentrations were measured using a modified Teco SP43 pulsed fluorescence analyzer. This insmnnent is equipped with a hydrocarbon "cutter" in the sample stream which is designed to selectively remove interfering aromatic hydrocarbons. A modified Monitor Labs 8840 chemilluminescence analyzer was used to measure NO concentrations; higher oxides of nitrogen were detected using a molybdenum converter operated at 375øC. We will refer to the total concentration of nitrogen oxides measured by this instrume...

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confidence: 90%

Heterogeneous chemistry in the smoke plume from the 1991 Kuwait oil fires

Herring¹,

Ferek²

1996

J. Geophys. Res.

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“…The secondary pollutants (SO 4 2− , NO 3 − , and NH 4 + ) in PM are photochemically converted from gases and comprise 2.4% of PM 10 and 3.7% of PM 2.5 . In particular, SO 4 2− is generated by secondary chemical reactions in the atmosphere [ 25 , 26 ], whereas NO 3 − is generated by combustion of fossil fuels [ 27 ]. When the subway service is inactive, a diesel motor car is operated to maintain the tunnel, and NO 3 − and SO 4 2− are transported from the outdoor air through the ventilation system [ 2 , 16 , 28 , 29 , 30 , 31 , 32 ].…”

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confidence: 99%

Sources and Characteristics of Particulate Matter in Subway Tunnels in Seoul, Korea

Lee

Kim

et al. 2018

IJERPH

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Hazards related to particulate matter (PM) in subway systems necessitate improvement of the air quality. As a first step toward establishing a management strategy, we assessed the physicochemical characteristics of PM in a subway system in Seoul, South Korea. The mean mass of PM10 and PM2.5 concentrations (n = 13) were 213.7 ± 50.4 and 78.4 ± 8.8 µg/m3, with 86.0% and 85.9% of mass concentration. Chemical analysis using a thermal–optical elemental/organic carbon (EC–OC) analyzer, ion chromatography (IC), and inductively coupled plasma (ICP) spectroscopy indicated that the chemical components in the subway tunnel comprised 86.0% and 85.9% mass concentration of PM10 and PM2.5. Fe was the most abundant element in subway tunnels, accounting for higher proportions of PM, and was detected in PM with diameters >94 nm. Fe was present mostly as iron oxides, which were emitted from the wheel–rail–brake and pantograph–catenary wire interfaces. Copper particles were 96–150 nm in diameter and were likely emitted via catenary wire arc discharges. Furthermore, X-ray diffraction analysis (XRD) showed that the PM in subway tunnels was composed of calcium carbonate (CaCO3), quartz (SiO2), and iron oxides (hematite (α-Fe2O3) and maghemite-C (γ-Fe2O3)). Transmission electron microscopy images revealed that the PM in subway tunnels existed as agglomerates of iron oxide particle clusters a few nanometers in diameter, which were presumably generated at the aforementioned interfaces and subsequently attached onto other PM, enabling the growth of aggregates. Our results can help inform the management of PM sources from subway operation.

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“…Fitting a Langmuir-Hinshelwood model, they found a heat of reaction 44.8 kJ/mol, with a heat of SO 2 adsorption of 27.6 kJ/mol. Baldwin [1982] measured SO2 uptake on charcoal at room temperature and found that the uptake is first order in both SO 2 concentration (3x10 -•$ to 3x10 -3 torr) and in the amount of charcoal with a maximum of about 1 mg SO 2 / g C. More recently, Molina-Sabio et al [1995] performed experiments at-10øC with SO2 partial pressures between 1 and 730 torr. In the -•1 torr range, SO2 had only weak interactions with the activated carbon surface.…”

Section: Introductionmentioning

confidence: 99%

A Fourier transform infrared study of the adsorption of SO₂ on n‐hexane soot from −130° to −40°C

Koehler¹,

Nicholson²,

Roe³

et al. 1999

J. Geophys. Res.

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Abstract. This paper focuses on the uptake of SO 2 on soot at temperatures below room temperature. Oxidation on soot may provide a mechanism for the oxidation of atmospheric SO2 under conditions when the standard gas-phase and aqueous-phase mechanisms cannot explain the rapid rate of H2SO4 production. An understanding of the uptake of SO2 under dry conditions provides a useful step toward understanding the uptake and oxidation of SO2 on soot under wet conditions. We find that rapid, reversible SO2 adsorption on soot occurs within a few seconds, presumably by adsorption on the outer surfaces of the spherical soot particles. Subsequently, uptake continues slowly for over an hour, presumably by diffusion into micropores within the soot particles. We focused only on the rapid adsorption. An isothermal analysis of rapid SO2 uptake revealed that a small fraction (<1%) of adsorption sites have a strong binding affinity (AHde s = 42+4 kJ/mol), while the majority of adsorption sites bind SO2 more weakly (26+4 kJ/mol). The lower-limit saturation coverage of SO2 on soot is 0.3 monolayer, but the more likely value is 0.7 monolayer. The uptake coefficient is 0.002 (plus or minus factor of 2) at low coverages.

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Heterogeneous reactions of sulfur dioxide with carbonaceous particles

Cited by 24 publications

References 10 publications

Heterogeneous chemistry in the smoke plume from the 1991 Kuwait oil fires

Heterogeneous chemistry in the smoke plume from the 1991 Kuwait oil fires

Sources and Characteristics of Particulate Matter in Subway Tunnels in Seoul, Korea

A Fourier transform infrared study of the adsorption of SO₂ on n‐hexane soot from −130° to −40°C

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Heterogeneous reactions of sulfur dioxide with carbonaceous particles

Cited by 24 publications

References 10 publications

Heterogeneous chemistry in the smoke plume from the 1991 Kuwait oil fires

Heterogeneous chemistry in the smoke plume from the 1991 Kuwait oil fires

Sources and Characteristics of Particulate Matter in Subway Tunnels in Seoul, Korea

A Fourier transform infrared study of the adsorption of SO2 on n‐hexane soot from −130° to −40°C

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A Fourier transform infrared study of the adsorption of SO₂ on n‐hexane soot from −130° to −40°C