Sulphur speciation in bitumens and asphaltenes by X-ray absorption fine structure spectroscopy

Kasrai, M.; Bancroft, G.M.; Brunner, R.W.; Jonasson, Ralph G.; Brown, James R.; Tan, K. H.; Feng, Xiaoping

doi:10.1016/0016-7037(94)90120-1

Cited by 43 publications

(28 citation statements)

References 18 publications

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“…They show similar values (Fig. 4), which means that sulphur is homogeneously distributed in both bulk and surface in agreement with previous works on similar materials.4*'2,18,'9*z6~78, 79 The intensity of the main component (S2) diminishes with increasing T, up to 1900°C [ Fig. 6(c)].…”

Section: Kinetic Energy (Ev)supporting

confidence: 92%

X-ray Photoelectron Spectroscopic Study of Petroleum Fuel Cokes

Mateos

Fierro

1996

Surf. Interface Anal.

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Section: Kinetic Energy (Ev)supporting

confidence: 92%

X-ray Photoelectron Spectroscopic Study of Petroleum Fuel Cokes

Mateos

Fierro

1996

Surf. Interface Anal.

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“…Sulfide represents less than 36% of the total sulphur present. This agrees with the a XANES study on bitumen showing thiophenic sulphur to be the dominant sulphur form (Kasrai et et, 1994). It should be mentioned that total weight The pentane insoluble end-cut accounts for about 20 w/w% of bitumen.…”

supporting

confidence: 77%

Molecular Nature of Athabasca Bitumen

Zhao

Kotlyar

Woods

et al. 2000

Petroleum Science and Technology

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Athabasca bitumen is a heavy hydrocarbon recovered from oil sands. During upgrading, bitumen is first distilled to remove lighter components which are processed in hydrotreaters. This distillable portion, heavy gas oil, accumulates nearly 80 w/w% of the saturates present in the original material. The aromatic character and heteroatorns content of the molecules in this fraction increase with the boiling point of the components. The residue from distillation, bitumen pitch, is subjected to thermal cracking followed by hydrotreating.The extractable front fractions from pitch show a trend for increasing aromatic content with a concomitant decrease in HIC atomic ratios. This is a reflection of greater numbers of aromatic rings with a higher degree of condensation and decreasing degree of substitution. The insoluble end-587

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“…Differential reduction of organic S compounds to H 2 S does not identify the organic functional groups or the intermediate oxidation states of S. The pyrolysis -gas chromatography -mass spectrometry approach is used for coal, kerogens and aquatic humic substances, but is limited to speciation of thermally stable forms of S. Within this context, S K-and L-edge XANES spectroscopy are proving to be invaluable, non-destructive, and in some cases in situ, techniques for characterizing the S functional groups in natural organic matter. The method has been applied to coals (e.g., Hussain et al 1982, Spiro et al 1984, Huffman et al 1991, George et al 1991, Brown et al 1992, Kasrai et al 1990, 1996b, Olivella et al 2002, Huggins et al 1997, heavy petroleum asphalts (bitumens) and asphaltenes (George & Gorbaty 1989, Gorbaty et al 1991, Waldo et al 1991, Kasrai et al 1994, Vairavamurthy et al 1994, Sarret et al 1999, kerogens , Sarret et al 2002 and sediments, soils and humus (Vairavamurthy et al 1994, 1997, Morra et al 1997, Olivella et al 2002, Qian et al 2002, Beauchemin et al 2002, Solomon et al 2003, Jokic et al 2003. FIG.…”

Section: Organic Geochemistrymentioning

confidence: 99%

Xanes Spectroscopy of Sulfur in Earth Materials

Fleet¹

2005

The Canadian Mineralogist

152

134

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X-ray absorption near-edge structure (XANES) spectroscopy is the ideal non-destructive technique for characterizing and quantifying S species in compositionally complex natural materials such as silicate glasses and minerals, coals, asphalts and asphaltenes, kerogens and humic substances. Sulfur absorption edges represent the transition of S 1s and 2p core electrons to unoccupied antibonding orbitals at the bottom of the conduction band. Shifts in the position of the absorption-edge feature of S K-and L-edge XANES spectra constitute a chemical ruler for oxidation state of both inorganic and organic species of S; the S K edge shifts from 2469.5 eV for chalcopyrite (2-oxidation state) to 2482 eV for gypsum (6+). However, chemical state of S in Earth materials is most readily assigned by comparing the overall XANES profi le with spectra for reference compounds. Sulfur XANES spectra are reviewed for pyrite, troilite, pyrrhotite and NiAs-type Co 0.923 S and Ni 0.923 S, niningerite (MgS), oldhamite (CaS), alabandite (MnS) and cubic FeS, and sphalerite and related phases, as well as for selected solid-solutions of the monosulfi des. Sulfur XANES spectra for FeS, CoS, NiS, MgS, CaS, MnS and ZnS have been simulated by multiple scattering calculations. The S K-edge XANES of transition-metal-bearing monosulfi des generally show anomalous absorption consistent with hybridization of the fi nal S 3p * antibonding states with empty 3d orbitals on the metal atoms. Various applications of S K-and L-edge XANES fi ngerprinting are discussed, including speciation of inorganic S in basaltic glasses, lazurite and haüyne, identifi cation of organic functional groups of S in coals, kerogens and humic substances extracted from subtropical soils and marine sediments, and the association of sulfated sugars with calcifi cation of coral aragonite skeletons.Keywords: XANES spectroscopy, chemical state of S, electronic structure and bonding, sulfi des, sulfates, magma, organic geochemistry. SOMMAIRELa spectroscopie d'absorption des rayons X dans la région pré-seuil (XANES) s'avère la technique non-destructive par excellence pour caractériser et quantifi er les espèces de soufre dans les matériaux naturels de composition complexe, par exemple les verres silicatés et minéraux, charbons, asphaltes et asphaltènes, kérogènes et substances humiques. Les seuils d'absorption du soufre résultent de la transition des électrons 1s et 2p du noyau à des orbites non occupés anti-liaisons à la base de la bande de conduction. Les décalages dans la position des seuils K et L du soufre des spectres XANES constituent un barème chimique important dans l'évaluation du niveau d'oxydation du soufre, à la fois pour les espèces inorganiques et organiques; le seuil K est déplacé de 2469.5 eV dans la chalcopyrite (valence 2-) à 2482 eV dans le gypse (6+). Toutefois, l'état du soufre des matériaux terrestres est plus facilement attribué en comparant le profi l XANES entier d'un échantillon aux spectres des composés de réfé-rence. Les spectres XANES du soufre so...

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Sulphur speciation in bitumens and asphaltenes by X-ray absorption fine structure spectroscopy

Cited by 43 publications

References 18 publications

X-ray Photoelectron Spectroscopic Study of Petroleum Fuel Cokes

X-ray Photoelectron Spectroscopic Study of Petroleum Fuel Cokes

Molecular Nature of Athabasca Bitumen

Xanes Spectroscopy of Sulfur in Earth Materials

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