Using X-ray absorption to probe sulfur oxidation states in complex molecules

Vairavamurthy, Appathurai

doi:10.1016/s1386-1425(98)00153-x

Cited by 130 publications

(145 citation statements)

References 15 publications

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“…Among them, peak A, which is quite close to the S 8 white line, can be assigned to the transition from S 1s core level to the S-S π* states. 25,[27][28] The strong S-S feature that can be observed for all the CSG samples is attributed to the fact that elemental sulfur is the main product of the reaction between the Na 2 S x and HCOOH solutions. Moreover, in comparison with the spectrum of elemental sulfur, 25 large differences can be observed in Figure 3(a),…”

Section: Interactions Among the Cathode Materialsmentioning

confidence: 92%

X-ray Absorption Spectroscopic Characterization of the Synthesis Process: Revealing the Interactions in Cetyltrimethylammonium Bromide-Modified Sulfur–Graphene Oxide Nanocomposites

Kawase

Song

et al. 2016

J. Phys. Chem. C

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We have investigated the chemical bonding interaction of S in a CTAB(cetyltrimethylammonium bromide, CH 3 (CH 2 ) 15 N + (CH 3 ) 3 Br -)-modified sulfur-graphene oxide (S-GO) nanocomposite used as the cathode material for Li/S cells by S K-edge X-ray absorption spectroscopy (XAS). The results show that the introduction of CTAB to the S-GO nanocomposite and changes in the synthesis recipe including alteration of the S precursor ratios and the sequence of mixing of ingredients lead to the formation of different S species. CTAB modifies the cathode materials through bonding with Na 2 S x in the precursor solution, which is subsequently converted to C-S bonds during the heat treatment at 155°C. Moreover, GO bonds with CTAB and acts as the nucleation center for S precipitation. All these interactions among S, CTAB and GO help to immobilize the sulfur in the cathode, and may be responsible for the enhanced cell cycle life of CTAB-S-GO nanocomposite-based Li/S cells.

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Section: Interactions Among the Cathode Materialsmentioning

confidence: 92%

X-ray Absorption Spectroscopic Characterization of the Synthesis Process: Revealing the Interactions in Cetyltrimethylammonium Bromide-Modified Sulfur–Graphene Oxide Nanocomposites

Kawase

Song

et al. 2016

J. Phys. Chem. C

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“…Sulfur K-edge XANES spectroscopy is a valuable technique for determining sulfur speciation because the absorption fine structure of the variety of sulfur forms are richly endowed with characteristic features, including edge energy, allowing the identification among various oxidation states and structures (18,19). Consequently, an XANES spectrum of a sample can be deconvoluted to derive information of the different sulfur constituents in the sample.…”

Section: Growth Of Cd-1 In Cd(ii) (I) Compositionmentioning

confidence: 99%

A New Klebsiella planticola Strain (Cd-1) Grows Anaerobically at High Cadmium Concentrations and Precipitates Cadmium Sulfide

Sharma

Balkwill

Frenkel

et al. 2000

Appl Environ Microbiol

131

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Heavy metal resistance by bacteria is a topic of much importance to the bioremediation of contaminated soils and sediments. We report here the isolation of a highly cadmium-resistant Klebsiella planticola strain, Cd-1, from reducing salt marsh sediments. The strain grows in up to 15 mM CdCl 2 under a wide range of NaCl concentrations and at acidic or neutral pH. In growth medium amended with thiosulfate, it precipitated significant amounts of cadmium sulfide (CdS), as confirmed by x-absorption spectroscopy. In comparison with various other strains tested, Cd-1 is superior for precipitating CdS in cultures containing thiosulfate. Thus, our results suggest that Cd-1 is a good candidate for the accelerated bioremediation of systems contaminated by high levels of cadmium.Cadmium, a highly toxic metal and a group B1 human carcinogen, is commonly ranked among the top 10 priority pollutants by U.S. regulatory agencies. Significant amounts of this metal often infiltrate the groundwater at hazardous waste sites. A practical approach to minimizing Cd(II) levels in the subsurface systems is precipitating it with hydrogen sulfide as the highly insoluble cadmium sulfide (CdS). In reducing environments, sulfate-reducing bacteria (SRB) generate hydrogen sulfide through dissimilatory sulfate reduction. However, little is known about the heavy metal resistance and growth of these bacteria in contaminated systems. Recent studies by Poulson et al. (14) and White and Gadd (22) indicate that even low levels of free Cd(II), Zn(II), or Ni(II) ions, i.e., 20 to 200 M, are toxic to SRB, such as Desulfovibrio and Desulfotomaculum. Our unpublished studies (P. K. Sharma and M. A. Vairavamurthy) also indicate that at least the SRB from coastal salt marshes from Shelter Island, New York, are sensitive to cadmium. However, a new Klebsiella planticola strain, Cd-1, from the same coastal environment grew to saturation in 15 mM Cd(II) ions in a minimal anaerobic medium, and after thiosulfate was added to the growth medium, it transformed significant amounts of the dissolved cadmium to CdS, up to 50 times higher than that reported for highly purified and continuously fed sulfate-reducing biofilms (22) Q-302, 1999). In general, facultative anaerobes, such as Cd-1, are attractive candidates for accelerated bioremediation applications, as large amounts of them can be grown rapidly with various nonhazardous substrates in aerobic reactors and can then be injected into anaerobic subsurface environments. In contrast, SRB often are slow growers and also may require expensive substrates, nutrients, or cofactors for growth.In this report, we describe the isolation and basic characteristics of strain Cd-1. We show that it can grow in high levels of Cd(II) ions under a wide range of environmental conditions, including high salinity and acidic pH. Importantly, our studies demonstrate that Cd-1 can transform high levels of cadmium to CdS in the presence of thiosulfate. We compared the growth and the ability of Cd-1 to produce CdS in media containing high...

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“…4. (a) Background-subtracted S L-edge XANES spectrum for galena, and (b) correlation plot between energy above threshold (⌬E) and 1/R 2 for peaks h (nearest-neighbor shell; S-Pb interaction), g (lattice spacing; d 111 ), f (second shell; S-S), and e (third shell; S-Pb) (after Kasrai et al 1991 Hitchcock et al 1987, Kitamura et al 1988, Vairavamurthy et al 1993a, b, Li et al 1995a, Womes et al 1997, Vairavamurthy 1998, Farrell & Fleet 2000, 2001, Farrell et al 2002, Paris et al 2001, Fleet et al 2005a. Representative K-and L 2,3 -edge XANES spectra for some minerals and synthetic compounds of known composition and structural or molecular state (reference compounds) are given in Figures 2 and 3, respectively.…”

Section: Introductionmentioning

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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Using X-ray absorption to probe sulfur oxidation states in complex molecules

Cited by 130 publications

References 15 publications

X-ray Absorption Spectroscopic Characterization of the Synthesis Process: Revealing the Interactions in Cetyltrimethylammonium Bromide-Modified Sulfur–Graphene Oxide Nanocomposites

X-ray Absorption Spectroscopic Characterization of the Synthesis Process: Revealing the Interactions in Cetyltrimethylammonium Bromide-Modified Sulfur–Graphene Oxide Nanocomposites

A New Klebsiella planticola Strain (Cd-1) Grows Anaerobically at High Cadmium Concentrations and Precipitates Cadmium Sulfide

Xanes Spectroscopy of Sulfur in Earth Materials

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