The effects of nitrate on the heterogeneous uptake of sulfur dioxide on hematite

Kong, Lingdong; Zhao, Xueyan; Sun, Zhenyu; Yang, Yiwei; Fu, Hongbo; Yang, Xin; Zhang, S. C.; Chen, J. M.; Wang, Lin; Cheng, Tiantao

doi:10.5194/acpd-14-11577-2014

Cited by 15 publications

(30 citation statements)

References 62 publications

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“…There have been a number of atmospheric chemistry models applied to predict the formation of sulfate aerosols on a global scale (Kasibhatla et al, 1997;Laskin et al, 2003). The results suggest that atmospheric SO 2 concentrations are typically overestimated, while sulfate concentrations tend to be underestimated (Kasibhatla et al, 1997;Laskin et al, 2003), and the two pathways including gaseous oxidation by OH radical and aqueous oxidation in cloud and fog droplets by ozone and hydrogen peroxide are insufficient to bridge the gap between field and modeling studies (Luria and Sievering, 1991). Including in-cloud oxidation catalyzed by natural transition metal ions in models will improve agreement between models and observations (Harris et al, 2013).…”

Section: Introductionmentioning

confidence: 98%

The effects of nitrate on the heterogeneous uptake of sulfur dioxide on hematite

et al. 2014

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Abstract. Nitrate is often found to be associated with atmospheric particles. Surface nitrate can change the hygroscopicity of these particles, and thus impact their chemical reactivity. However, the influence of nitrate on heterogeneous reactions of atmospheric trace gases is poorly understood. In this work, the effects of nitrate on heterogeneous conversion of SO2 with hematite at 298 K are investigated using an in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and a White cell coupled with Fourier transform infrared spectroscopy (White cell-FTIR). It is found that nitrate participates in heterogeneous reactions of SO2, accelerates the formation rate of sulfate, and leads to the formation of surface-adsorbed HNO3 and gas-phase N2O and HONO. The results indicate that low to moderate amounts of nitrate significantly enhance the reactivity of hematite–nitrate mixtures, the uptake of SO2, and the formation of sulfate on hematite. For mixtures, the sample containing 24% nitrate exhibits the highest sulfate formation rate, and its corresponding uptake coefficient calculated by geometric surface area is about 5.5 times higher than that of hematite alone. The sample containing 48% nitrate presents the highest Brunauer–Emmett–Teller (BET) uptake coefficient, and the value is about 8 times higher than that of pure hematite. No uptake of SO2 and formation of sulfate are observed on pure nitrate. Evidence presented herein implies a significant contribution of the unreleased HNO3 and HONO in the particles for the conversion of SO2 and the enhanced formation of sulfate in the atmosphere. A possible mechanism for the influence of nitrate on the heterogeneous conversion of SO2 on hematite is proposed, and atmospheric implications based on these results are discussed.

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Section: Introductionmentioning

confidence: 98%

The effects of nitrate on the heterogeneous uptake of sulfur dioxide on hematite

et al. 2014

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“…Transition metal ions, i.e., Mn(II) and Fe(III) were found present common in dust particles and lead to significantly catalytic oxidation of S(IV) with dissolved oxygen in aqueous phase 5 , 33 . For iron-containing dust, a number of studies are available investigating the influences of its morphology and existing water on the heterogeneous oxidation of SO 2 25 , 29 , 34 – 36 . For instance, Fu et al .…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Reaction of SO2 on Manganese Oxides: the Effect of Crystal Structure and Relative Humidity

Yang

Zhang

et al. 2017

Sci Rep

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Manganese oxides from anthropogenic sources can promote the formation of sulfate through catalytic oxidation of SO2. In this study, the kinetics of SO2 reactions on MnO2 with different morphologies (α, β, γ and δ) was investigated using flow tube reactor and in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). Under dry conditions, the reactivity towards SO2 uptake was highest on δ-MnO2 but lowest on β-MnO2, with a geometric uptake coefficient (γobs) of (2.42 ± 0.13) ×10–2 and a corrected uptake coefficient (γc) of (1.48 ± 0.21) ×10−6 for the former while γobs of (3.35 ± 0.43) ×10−3 and γc of (7.46 ± 2.97) ×10−7 for the latter. Under wet conditions, the presence of water altered the chemical form of sulfate and was in favor for the heterogeneous oxidation of SO2. The maximum sulfate formation rate was reached at 25% RH and 45% for δ-MnO2 and γ-MnO2, respectively, possibly due to their different crystal structures. The results suggest that morphologies and RH are important factors influencing the heterogeneous reaction of SO2 on mineral aerosols, and that aqueous oxidation process involving transition metals of Mn might be a potential important pathway for SO2 oxidation in the atmosphere.

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“…These new bands generated on the processed NAu-2 particles suggested that CP changed the location of diverse OH groups on the particle surfaces. Over the range of 1250-1000 cm -1 , the new bands centered at 1170 cm -1 was assigned to the asymmetric stretching of sulfate (Kong et al, 2014;Yang et al, 2015).…”

Section: Effect Of Simulated Cp On Heterogeneous Transformation Of So2mentioning

confidence: 99%

“…The reactive uptake coefficient (γ) was defined as the rate of sulfate formation on the surface (d[SO4 2− ]/dt, ions s -1 ) divided by collision frequency (Z, molecules s -1 ) (Usher et al, 2003;Ullerstam et al, 2003;Kong et al, 2014;Huang et al, 2015)…”

Section: So2 Uptake On the Mineral Particlesmentioning

confidence: 99%

“…2016), leading to a large gap between the modeled and field-observed sulfate concentrations using known oxidation pathways (Herman, 1991;Kasibhatla et al, 1997; Barrie et al, 2016). Overall, on a global scale, atmospheric SO2 concentration were typically overestimated, while sulfate tended to be underestimated, suggesting missing sulfate production pathways (Harris et al, 2013;Kong et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Enhanced heterogeneous uptake of sulfur dioxide on mineral particles through modification of iron speciation during simulated cloud processing

Wang¹,

Wang²,

Fu³

et al. 2019

Preprint

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Abstract. Iron-containing mineral aerosols play a key role in the oxidation of sulfur species in the atmosphere. Simulated cloud processing (CP) of typical mineral particles, such as illite (IMt-2), nontronite (NAu-2), smectite (SWy-2) and Arizona test dust (ATD) is shown here to modify sulfur dioxide (SO2) uptake onto mineral surfaces. Heterogeneous oxidation of SO2 on particle surfaces was firstly investigated using an in situ DRIFTS apparatus. Our results showed that the BET surface area normalized uptake coefficients (&#947;BET) of SO2 on the IMt-2, NAu-2, SWy-2 and ATD samples after CP were 2.2, 4.1, 1.5 and 1.4 times higher than the corresponding ones before CP, respectively. The DRIFTS results suggested that CP increased the amounts of reactive sites (e.g., surface OH groups) on the particle surfaces and thus enhanced the uptake of SO2. TEM showed that the particles broke up into smaller pieces after CP, and thus produced more active sites. The <q>free-Fe</q> measurements confirmed that more reactive Fe species were present after CP, which could enhance the SO2 uptake more effectively. Mo&#776;ssbauer spectroscopy further revealed that the formed Fe phase were amorphous Fe(III) and nanosized ferrihydrite hybridized with Al/Si, which were possibly transformed from the Fe in the aluminosilicate lattice. The modification of Fe speciation was driven by the pH-dependent fluctuation coupling with Fe dissolution-precipitation repeatedly during the experiment. Considering both the enhanced SO2 uptake and subsequent promotion of iron dissolution along with more active Fe formation, which in turn lead to more SO2 uptake, it was proposed that there may be a positive feedback between SO2 uptake and iron mobilized on particle surfaces during CP, thereby affecting climate and biogeochemical cycles. This self-amplifying mechanism generated on the particle surfaces may also serve as the basis of high sulfate loading in severe fog-haze events observed recently in China.

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The effects of nitrate on the heterogeneous uptake of sulfur dioxide on hematite

Cited by 15 publications

References 62 publications

The effects of nitrate on the heterogeneous uptake of sulfur dioxide on hematite

The effects of nitrate on the heterogeneous uptake of sulfur dioxide on hematite

Heterogeneous Reaction of SO2 on Manganese Oxides: the Effect of Crystal Structure and Relative Humidity

Enhanced heterogeneous uptake of sulfur dioxide on mineral particles through modification of iron speciation during simulated cloud processing

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