Determination of the chemical environment of sulphur in petroleum asphaltenes by X-ray absorption spectroscopy

Waldo, Geoffrey S.; Mullins, Oliver C.; Penner‐Hahn, James E.; Cramer, Stephen P.

doi:10.1016/0016-2361(92)90192-q

Cited by 139 publications

(127 citation statements)

References 11 publications

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“…These results Organic S originates mainly from plant and animal compare positively with the results of Stanko-Golden residues, which are subsequently decomposed and reand Fitzgerald (1991), who demonstrated using a wetmetabolized by soil microorganisms. Several early studchemical degradation technique that sulfonates are the ies conducted on speciation of S involving differential dominant components of the C-bonded S pool reprereduction techniques indicate that ester-SO 4 -S, where senting as much as 68% of the total S of forest-derived S is bonded to O in the form of R-OSO 3 -H linkages, is soils from Puerto Rico.…”

Section: Compounds In Size Separatessupporting

confidence: 79%

Sulfur K‐edge XANES Spectroscopy as a Tool for Understanding Sulfur Dynamics in Soil Organic Matter

Solomon

Lehmann

Martı́nez

2003

Soil Science Soc of Amer J

116

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ABSTRACTin oxidation states. Sulfur occurs in soil both in organic and inorganic forms. However, most of the soil S Sulfur K-edge X-ray absorption spectroscopy (XANES) was used (Ͼ95%) in temperate and tropical ecosystems is present to identify S oxidation states and assess the impact of land use changes on the amount, form, and distribution of organic S in particle-size in organic forms (Janzen and Ellert, 1998; separates and their humic substance extracts. Soil samples (0-10 cm)1998; Solomon et al., 2001a tempted to speciate S into its functional groups using follow its dynamics in terrestrial ecosystems.pyrolysis gas chromatography mass spectrometry in aquatic humic substances (Van Loon et al., 1993) and kerogens (Carmo et al., 1997) for characterization of S ulfur is a highly reactive element, existing in several S containing moieties, but this approach is limited to oxidation states and moving freely among the lithospeciation of thermally stable forms of S (Hundal et sphere, hydrosphere, and atmosphere. The accumulaal., 2000). tion and cycling of S are central to many biological Synchrotron-based S K-edge XANES spectroscopy processes and provide a key to understanding changes in has been successfully used to speciate and quantify all the biosphere. Sulfur cycling also significantly influences oxidation states of S in a variety of geochemical samples atmospheric and oceanic chemistry and the global enranging from petroleum (Waldo et al., 1991a,b), coal ergy balance. Therefore, the chemistry of S compounds (Huffman et al., 1995), marine sediments (Vairavamurin the environment has taken on a new significance in thy et al., 1993, 1994), biosolids (Hundal et al., 2000) to recent years because human activities have dramatically soil humic and fulvic acids (Morra et al., 1997; Xia et altered the biogeochemical S cycling in terrestrial ecoal., 1998; Szulczewski et al., 2001). X-ray absorption systems.near-edge structure spectroscopy has also proven to be The soil environment is the primary component of a valuable tool in the identification and quantification the global biogeochemical S cycle, acting as a source of S oxidation states in organic soils (Martínez et al., and sink for various S species and mediating changes 2002 need to conduct comparative studies that involve land cm. Crop residues that remain on the fields are normally use changes, which may help to describe important reaccollected and used as animal feed at both sites.tions of S to long-term management changes. This techWe selected three representative fields from each land use system. After considering the depth of cultivation to minimize nique can be combined with physical fractionation of differences, which may arise due to the dilution of SOM from soil according to particle-size separates, which has been mixing of the surface soil with the subsoil through cultivation, demonstrated to provide ecologically meaningful soil S we used a core sampler (200 cm 3 core volume) and collected pools (Solomon et al., 2001a). Thus, S K-edge XANES nine subsample...

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Section: Compounds In Size Separatessupporting

confidence: 79%

Sulfur K‐edge XANES Spectroscopy as a Tool for Understanding Sulfur Dynamics in Soil Organic Matter

Solomon

Lehmann

Martı́nez

2003

Soil Science Soc of Amer J

116

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“…Sulphur K edges of the samples were fitted by minimising the least squared difference of the experimental spectrum and a sum of synthetic edges, with the fractions of each type of sulphur as variables. two formations are similar with a sharp white line close to 2474 eV, indicating, in agreement with Waldo et al (1992), a high thiophenic sulphur content. Absorption edges for the kerogens begin at lower energies and are significantly wider, suggesting that these contain additional organic or mineral (iron) sulphides.…”

Section: Methodssupporting

confidence: 81%

“…Although oscillations after the edge are not taken into consideration, the model provides a good first approximation to the edge shape. The candidates for the types of sulphur present in asphaltenes, kerogens and the solids resulting from pyrolysis with their corresponding values of Eo (checked for consistency with those of Waldo et al (1992) using benzyl sulphide, dibenzothiophene and potassium sulphate references) are FeS (2470.3 eV), FeS2 (2471.6 eV), organic sulphide (2473.4 eV), thiophenic sulphur (2474.1 eV), oxidised organic sulphur (2480.9 eV) and sulphates (2482.6 eV). Sulphur K edges of the samples were fitted by minimising the least squared difference of the experimental spectrum and a sum of synthetic edges, with the fractions of each type of sulphur as variables.…”

Section: Methodsmentioning

confidence: 99%

“…George et al (1990) used the third derivative of the experimental data in order to show up differences in the composition of sulphur containing asphaltenes. Waldo et al (1992) used a superposition of model compound spectra to analyse a series of asphaltenes. Kerogens may contain a large range of sulphur types : FeS, FeS2, organic sulphides, thiophenic sulphur, and oxidised forms.…”

Section: Introductionmentioning

confidence: 99%

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Evolution of sulfur during pyrolysis of petroleum kerogens

Lynch¹,

Everlien²,

Leblond³

et al. 1999

J Synchrotron Radiat

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Sulphur K edge spectroscopy was used to differentiate types of sulphur present in petroleum asphaltenes and kerogens. A simplified model of the near edge structure enabled quantification of the different sulphur forms. The evolution of the sulphur edge following pyrolysis of kerogens confirms that thiophenic sulphur is more stable than organic sulphide forms. Pyrite retained in the kerogens may partially transform to iron sulphate during air storage. During pyrolysis FeS2 is regenerated and subsequently converted to FeS, contributing to the release of H2S. The results show that exchange between organic and mineral forms of sulphur is limited.

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“…More highly condensed thiophene types may also occur in the asphaltene fraction but are precluded from identification by low volatility. Other forms of sulfur that occur in asphaltenes include the alkyl-alkyl sulfides, alkyl-aryl sulfides and aryl-aryl sulfides (Yen, 1974;Waldo et al, 1992).…”

Section: Sulfurmentioning

confidence: 99%

Application of Spectroscopic Techniques to the Structural Analysis of Petroleum

Speight

1994

Applied Spectroscopy Reviews

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Determination of the chemical environment of sulphur in petroleum asphaltenes by X-ray absorption spectroscopy

Cited by 139 publications

References 11 publications

Sulfur K‐edge XANES Spectroscopy as a Tool for Understanding Sulfur Dynamics in Soil Organic Matter

Sulfur K‐edge XANES Spectroscopy as a Tool for Understanding Sulfur Dynamics in Soil Organic Matter

Evolution of sulfur during pyrolysis of petroleum kerogens

Application of Spectroscopic Techniques to the Structural Analysis of Petroleum

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