Speciation of sulfate components in size-fractionated aerosol particles using sulfur K-edge X-ray absorption near-edge structure (XANES)

Takahashi, Yoshio; Kanai, Yutaka; Kamioka, Hikari; Ohta, Atsuyuki; Miyoshi, Takuro; Shimizu, Hiroshi

doi:10.1007/bf02840173

Cited by 4 publications

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“…For example, the spectra for the aerosols collected in Qingdao during the dust period were shown with the spectra of gypsum and ammonium sulfate, (NH 4 ) 2 SO 4 (Figure 3b). Takahashi et al (20) demonstrated that the postedge structure is sensitive to the sulfate formed in the sample. Consequently, it was found that the spectra can be well fitted by a combination of gypsum and (NH 4 ) 2 SO 4 (20).…”

Section: Resultsmentioning

confidence: 99%

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Neutralization of Calcite in Mineral Aerosols by Acidic Sulfur Species Collected in China and Japan Studied by Ca K-edge X-ray Absorption Near-Edge Structure

Takahashi

Miyoshi

Higashi

et al. 2009

Environ. Sci. Technol.

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Calcium species in mineral aerosols collected simultaneously in Aksu (near the Taklimakan Desert), Qingdao (eastern China), and Tsukuba (Japan) during dust and nondust periods were determined using Ca K-edge X-ray absorption near-edge structure (XANES). From the fitting of XANES spectra, it was found that (i) calcite and gypsum were the main Ca species in the aerosol samples, and (ii) the gypsum fraction versus total Ca minerals [Gyp]/[Ca2+]t increased progressively in the order Aksu < Qingdao < Tsukuba. Surface-sensitive XANES in the conversion electron yield mode (CEY) showed that the gypsum is formed selectively at the surface of mineral aerosols for all the samples except for that taken in Aksu during the dust period. The decrease of the [Gyp]/[Ca2+]t ratio with an increase in particle size showed that the neutralization effect proceeds from the particle surface. For the Aksu sample in the dust period, however, (i) the [Gyp]/[Ca2+]t ratios obtained by XANES measured in the fluorescence (FL; regarded as bulk analysis) and CEY modes were similar and (ii) size dependence was not found, showing that neutralization is not important for the sample because of the large supply of mineral aerosol with little neutralization effect in Aksu. It was also found that the pH of the aerosol and the ratio of (NH4)2SO4 to gypsum were positively and negatively correlated with the Ca (or calcite) content, respectively. The speciation of Ca by XANES revealed the neutralization processes of acidic sulfur species by calcite during the long-range transport of mineral aerosols.

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Section: Resultsmentioning

confidence: 99%

“…Takahashi et al (20) demonstrated that the postedge structure is sensitive to the sulfate formed in the sample. Consequently, it was found that the spectra can be well fitted by a combination of gypsum and (NH 4 ) 2 SO 4 (20). The linear combination of the two end members thus enabled us to obtain the main sulfur compounds in the aerosols.…”

Section: Resultsmentioning

confidence: 99%

Neutralization of Calcite in Mineral Aerosols by Acidic Sulfur Species Collected in China and Japan Studied by Ca K-edge X-ray Absorption Near-Edge Structure

Takahashi

Miyoshi

Higashi

et al. 2009

Environ. Sci. Technol.

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“…Takahashi et al: Change of iron species and iron solubility in Asian dust It is strongly suggested that the bioavailability of Fe is influenced by its solubility which in turn is dependent on chemical species of Fe contained in Asian dust. Thus, to accurately assess the biogeochemical impact of the atmospheric input, an attempt was made in this study to identify the Fe species and quantify each species by synchrotronbased X-ray absorption fine structure (XAFS) spectroscopy, a powerful technique used to investigate chemical speciation in aerosol samples (Takahashi et al, 2006;Higashi and Takahashi, 2009;Schroth et al, 2009;Furukawa and Takahashi, 2011). The speciation data were confirmed by Xray diffraction and chemical extraction method to identify specific phases.…”

Section: Introductionmentioning

confidence: 99%

Change of iron species and iron solubility in Asian dust during the long-range transport from western China to Japan

et al. 2011

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In the North Pacific, transport and deposition of mineral dust from Asia appear to be one of major sources of iron which can regulate growth of phytoplankton in the ocean. In this process, it is essential to identify chemical species of iron contained in Asian dust, because bioavailability of iron in the ocean is strongly influenced by the solubility of iron, which in turn is dependent on iron species in the dust. Here, we report that clay minerals (illite and chlorite) in the dusts near the source collected at Aksu (western China) can be transformed into ferrihydrite by atmospheric chemical processes during their long-range transport to eastern China (Qingdao) and Japan (Tsukuba) based on the speciation by X-ray absorption fine structure (XAFS) and other methods such as X-ray diffraction and chemical extraction. As a result, Fe molar ratio in Aksu (illite : chlorite : ferrihydrite = 70 : 25 : 5) was changed to that in Tsukuba (illite : chlorite : ferrihydrite = 65 : 10 : 25). Moreover, leaching experiments were conducted to study the change of iron solubility. It was found that the iron solubility for the dust in Tsukuba (soluble iron fraction: 11.8 % and 1.10 % for synthetic rain water and seawater, respectively) was larger than that in Aksu (4.1 % and 0.28 %, respectively), showing that iron in the dust after the transport becomes more soluble possibly due to the formation of ferrihydrite in the atmosphere. Our findings suggested that secondary formation of ferrihydrite during the transport should be considered as one of important processes in evaluating the supply of soluble iron to seawater

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“…It was also found that the pH of the aerosol and the ratio of (NH 4 ) 2 SO 4 to gypsum determined by sulfur K-edge XANES ( Fig. 2; Takahashi et al 2006Takahashi et al , 2009 were positively, and negatively, correlated with the calcium (or calcite) content, respectively. The speciation of calcium by XANES revealed the neutralization processes of acidic sulfur species during the transport of mineral aerosols.…”

Section: Introductionmentioning

confidence: 82%

“…Thus, the formation process of sulfate aerosols from SO 2 gas in the atmosphere is important in relation to its global cooling effect. Here, sulfur Kedge XANES was applied to the determination and quantification of tetravalent sulfur species in aerosol samples collected at Qingdao (Takahashi et al 2006;Higashi and Takahashi 2009). Sulfite, tetravalent sulfur species, can be formed during the oxidation of SO 2 to sulfate, but the sulfite is usually regarded as an unstable species that can be finally oxidized to sulfate under the oxic condition of the atmosphere.…”

Section: Study 3: Evidence Of Oxidation Of So 2 At the Surface Of Minmentioning

confidence: 99%

A Study of the Chemical Processes in Aerosols and Their Impacts on the Environment Using X-ray Absorption Fine Structure Spectroscopy

Takahashi¹,

Higashi²,

Furukawa³

et al. 2014

Western Pacific Air-Sea Interaction Study

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The chemical processes occurring in aerosols are complex, but most of the previous studies have speculated such processes based on the relative abundances of various chemical components in the aerosols. In this study, XAFS has been applied to the speciation of calcium, sulfur, zinc, and iron that are related to the neutralization of acid depositions, the cooling effect of the Earth, and nutrients to phytoplankton in the open ocean. Study 1: Neutralization of Acidic Species in the Atmosphere by Asian Dust Calcite, CaCO 3 , is abundant in Asian dust (around 10 wt.%), which is a compound reactive toward acidic species such as sulfuric and nitric acids. We employed X-ray absorption near-edge structure (XANES; XAFS consists of XANES and EXAFS (extended X-ray absorption fine structure) depending on the energy region within the XAFS spectrum) to determine calcium and sulfur species in aerosols (i) to obtain the ratio of calcite and gypsum (CaSO 4 •2H 2 O), the main calcium species

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Speciation of sulfate components in size-fractionated aerosol particles using sulfur K-edge X-ray absorption near-edge structure (XANES)

Cited by 4 publications

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Neutralization of Calcite in Mineral Aerosols by Acidic Sulfur Species Collected in China and Japan Studied by Ca K-edge X-ray Absorption Near-Edge Structure

Neutralization of Calcite in Mineral Aerosols by Acidic Sulfur Species Collected in China and Japan Studied by Ca K-edge X-ray Absorption Near-Edge Structure

Change of iron species and iron solubility in Asian dust during the long-range transport from western China to Japan

A Study of the Chemical Processes in Aerosols and Their Impacts on the Environment Using X-ray Absorption Fine Structure Spectroscopy

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