Heterogeneous Uptake and Oxidation of SO<sub>2</sub> on Iron Oxides

Fu, Hongbo; Wang, Xiao; Wu, Haixia; Yin, and Yong; Chen, Jianmin

doi:10.1021/jp070087b

Cited by 215 publications

(201 citation statements)

References 39 publications

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“…As a result, elemental mercury capture by (Fe 3-xTi x ) 1-δ O 4 (reaction 7) would reach the optimal condition at a specific temperature, in most cases not the highest temperature. Previous research postulated a mechanism for the heterogeneous uptake and oxidization of SO 2 on iron oxides, 56 and the reactions can be described as follows:…”

Section: Resultsmentioning

confidence: 99%

Nanosized Cation-Deficient Fe−Ti Spinel: A Novel Magnetic Sorbent for Elemental Mercury Capture from Flue Gas

Yang

Guo

Yan

et al. 2011

ACS Appl. Mater. Interfaces

140

133

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Section: Resultsmentioning

confidence: 99%

Nanosized Cation-Deficient Fe−Ti Spinel: A Novel Magnetic Sorbent for Elemental Mercury Capture from Flue Gas

Yang

Guo

Yan

et al. 2011

ACS Appl. Mater. Interfaces

140

133

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“…Hematite, goethite, magnetite and TiO 2 have all been shown to chemisorb SO 2 to a bidentate complex, with similar IR spectral bands observed for the adsorbed compounds where available. This suggests these three iron oxides will also have the same value for α as TiO 2 and by extension the same α as ilmenite (Fu et al, 2007;Zhang et al, 2006;Usher et al, 2002). Mineral assemblage 1 also has a significant amount of Ca.…”

Section: Mineral Assemblagementioning

confidence: 90%

Sulfur isotope fractionation during heterogeneous oxidation of SO<sub>2</sub> on mineral dust

Harris

Sinha

Foley³

et al. 2012

Atmos. Chem. Phys.

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Abstract. Mineral dust is a major fraction of global atmospheric aerosol, and the oxidation of SO 2 on mineral dust has implications for cloud formation, climate and the sulfur cycle. Stable sulfur isotopes can be used to understand the different oxidation processes occurring on mineral dust. This study presents measurements of the 34 S/ 32 S fractionation factor α 34 for oxidation of SO 2 on mineral dust surfaces and in the aqueous phase in mineral dust leachate. Sahara dust, which accounts for ∼60 % of global dust emissions and loading, was used for the experiments.The fractionation factor for aqueous oxidation in dust leachate is α leachate = 0.9917±0.0046, which is in agreement with previous measurements of aqueous SO 2 oxidation by iron solutions. This fractionation factor is representative of a radical chain reaction oxidation pathway initiated by transition metal ions. Oxidation on the dust surface at subsaturated relative humidity (RH) had an overall fractionation factor of α het = 1.0096 ± 0.0036 and was found to be almost an order of magnitude faster when the dust was simultaneously exposed to ozone, light and RH of ∼40 %. However, the presence of ozone, light and humidity did not influence isotope fractionation during oxidation on dust surfaces at subsaturated relative humidity. All the investigated reactions showed mass-dependent fractionation of 33 S relative to 34 S.A positive matrix factorization model was used to investigate surface oxidation on the different components of dust. Ilmenite, rutile and iron oxide were found to be the most reactive components, accounting for 85 % of sulfate production with a fractionation factor of α 34 = 1.012±0.010. This overlaps within the analytical uncertainty with the fractionation of other major atmospheric oxidation pathways such as the oxidation of SO 2 by H 2 O 2 and O 3 in the aqueous phase and OH in the gas phase. Clay minerals accounted for roughly 12 % of the sulfate production, and oxidation on clay minerals resulted in a very distinct fractionation factor of α 34 = 1.085±0.013. The fractionation factors measured in this study will be particularly useful in combination with field and modelling studies to understand the role of surface oxidation on clay minerals and aqueous oxidation by mineral dust and its leachate in global and regional sulfur cycles.

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“…Saturation of the sensor surface was faster during exposure to higher concentrations of SO 2 . This might be caused by the increased rate of SO 2 oxidation to SO 3 or SO 4 , which enhance the uptake of the sulfur containing gas by the oxide surface [29] and the difficulty to release the molecules. …”

Section: Influence Of Oxygen Concentrationmentioning

confidence: 99%

SiC–FET based SO2 sensor for power plant emission applications

Darmastuti

Bur

Möller

et al. 2014

Sensors and Actuators B: Chemical

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Thermal power plants produce SO 2 during combustion of fuel containing sulfur. One way to decrease the SO 2 emission from power plants is to introduce a sensor as part of the control system of the desulphurization unit. In this study, SiC-FET sensors were studied as one alternative sensor to replace the expensive FTIR (Fourier Transform Infrared) instrument or the inconvenient wet chemical methods. The gas response for the SiC-FET sensors comes from the interaction between the test gas and the catalytic gate metal, which changes the electrical characteristics of the devices. The performance of the sensors depends on the ability of the test gas to be adsorbed, decomposed, and desorbed at the sensor surface. The feature of SO 2 , that it is difficult to desorb from the catalyst surface, makes it known as catalyst poison.It is difficult to quantify the SO 2 with static operation, even at the optimum operation temperature of the sensor due to low response levels and saturation already at low concentration of SO 2 . The challenge of SO 2 desorption can be reduced by introducing dynamic operation in a designed temperature cycle operation (TCO). The intermittent exposure to high temperature can help to desorb SO 2 . Simultaneously, additional features extracted from the sensor data can be used to reduce the influence of sensor drift. The TCO operation, together with pattern recognition, may also reduce the baseline and response variation due to changing concentration of background gases (4-10% O 2 and 0-70% RH), and thus it may improve the overall sensor performance. In addition to the laboratory experiment, testing in the desulphurization pilot unit was performed. Desulphurization pilot unit has less controlled environment compared to the laboratory conditions. Therefore, the risk of influence from the changing concentration of background gas is higher. In this study, Linear Discriminant Analysis (LDA) and Partial Least Square (PLS) were employed as pattern recognition methods. It was demonstrated that using LDA quantification of SO 2 into several groups of concentrations up to 2000 ppm was possible. Additionally, PLS analysis indicated a good agreement between the predicted value from the model and the SO 2 concentration from the reference instrument of the pilot plant. 3 IntroductionSO 2 is one of the major air pollutants because it is a precursor of acid rain, forms acid particulates, and is dangerous for human health. However, in a thermal power plant, SO 2 is generally produced when sulfur containing fuel is combusted. In flue gas cleaning processes, SO 2 is usually removed by absorption with lime (CaOH 2 .2H 2 O) or other compounds having high alkalinity. State-of-the-art desulphurization can remove more than 98% of the SO 2 from the flue gas. With increasing environmental concerns, the regulation of SO 2 emission from thermal power plants has become stricter. The installation of sensors in the flue gas duct has been proposed as one of the alternatives to improve the efficiency of the desulphurization un...

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Heterogeneous Uptake and Oxidation of SO₂ on Iron Oxides

Cited by 215 publications

References 39 publications

Nanosized Cation-Deficient Fe−Ti Spinel: A Novel Magnetic Sorbent for Elemental Mercury Capture from Flue Gas

Nanosized Cation-Deficient Fe−Ti Spinel: A Novel Magnetic Sorbent for Elemental Mercury Capture from Flue Gas

Sulfur isotope fractionation during heterogeneous oxidation of SO<sub>2</sub> on mineral dust

SiC–FET based SO2 sensor for power plant emission applications

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Heterogeneous Uptake and Oxidation of SO2 on Iron Oxides

Cited by 215 publications

References 39 publications

Nanosized Cation-Deficient Fe−Ti Spinel: A Novel Magnetic Sorbent for Elemental Mercury Capture from Flue Gas

Nanosized Cation-Deficient Fe−Ti Spinel: A Novel Magnetic Sorbent for Elemental Mercury Capture from Flue Gas

Sulfur isotope fractionation during heterogeneous oxidation of SO&lt;sub&gt;2&lt;/sub&gt; on mineral dust

SiC–FET based SO2 sensor for power plant emission applications

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Product

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Heterogeneous Uptake and Oxidation of SO₂ on Iron Oxides

Sulfur isotope fractionation during heterogeneous oxidation of SO<sub>2</sub> on mineral dust