Equilibrium Distribution of Polysulfide Ions in Aqueous Solutions at 25 °C:  A New Approach for the Study of Polysulfides' Equilibria

Kamyshny, Alexander; Goifman, A.; Gun, Jenny; Rizkov, Dan; Lev, Ovadia

doi:10.1021/es049514e

Cited by 198 publications

(210 citation statements)

References 40 publications

(70 reference statements)

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“…The ferrous iron can result from iron (oxyhydr) oxide reduction coupled to in situ sulfide oxidation, but it can also diffuse to the sulfidic zone-originating from the upper sediment layers and associated organoclastic iron reduction and the lowermost sediments via iron-reduction coupled to AOM as discussed by Riedinger et al (2014) for Site GeoB 13863. In absence of free sulfide, or at low pH (Kamyshny et al, 2004(Kamyshny et al, , 2007(Kamyshny et al, , 2008Kamyshny and Ferdelman, 2010), elemental sulfur is the stable zero-valent sulfur phase. At the investigated sites, the pH is high (7.66-8.14 in the sulfidic zone at Site GeoB 13863).…”

Section: Formation Of Iron Monosulfide and Elemental Sulfurmentioning

confidence: 99%

Sulfur Cycling in an Iron Oxide-Dominated, Dynamic Marine Depositional System: The Argentine Continental Margin

Riedinger

Brunner

Krastel³

et al. 2017

Front. Earth Sci.

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The interplay between sediment deposition patterns, organic matter type and the quantity and quality of reactive mineral phases determines the accumulation, speciation, and isotope composition of pore water and solid phase sulfur constituents in marine sediments. Here, we present the sulfur geochemistry of siliciclastic sediments from two sites along the Argentine continental slope-a system characterized by dynamic deposition and reworking, which result in non-steady state conditions. The two investigated sites have different depositional histories but have in common that reactive iron phases are abundant and that organic matter is refractory-conditions that result in low organoclastic sulfate reduction rates (SRR). Deposition of reworked, isotopically light pyrite and sulfurized organic matter appear to be important contributors to the sulfur inventory, with only minor addition of pyrite from organoclastic sulfate reduction above the sulfate-methane transition (SMT). Pore-water sulfide is limited to a narrow zone at the SMT. The core of that zone is dominated by pyrite accumulation. Iron monosulfide and elemental sulfur accumulate above and below this zone. Iron monosulfide precipitation is driven by the reaction of low amounts of hydrogen sulfide with ferrous iron and is in competition with the oxidation of sulfide by iron (oxyhydr)oxides to form elemental sulfur. The intervals marked by precipitation of intermediate sulfur phases at the margin of the zone with free sulfide are bordered by two distinct peaks in total organic sulfur (TOS).Organic matter sulfurization appears to precede pyrite formation in the iron-dominated margins of the sulfide zone, potentially linked to the presence of polysulfides formed by reaction between dissolved sulfide and elemental sulfur. Thus, SMTs can be hotspots for organic matter sulfurization in sulfide-limited, reactive iron-rich marine sedimentary systems. Furthermore, existence of elemental sulfur and iron monosulfide phases meters below the SMT demonstrates that in sulfide-limited systems metastable sulfur constituents are not readily converted to pyrite but can be buried to deeper Riedinger et al.Non-steady State Subsurface Sulfur Cycling sediment depths. Our data show that in non-steady state systems, redox zones do not occur in sequence but can reappear or proceed in inverse sequence throughout the sediment column, causing similar mineral alteration processes to occur at the same time at different sediment depths.

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Section: Formation Of Iron Monosulfide and Elemental Sulfurmentioning

confidence: 99%

Sulfur Cycling in an Iron Oxide-Dominated, Dynamic Marine Depositional System: The Argentine Continental Margin

Riedinger

Brunner

Krastel³

et al. 2017

Front. Earth Sci.

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“…The S n 2-polysulfide species that are favored in S 0 -rich systems -predominantly S 4 -2 , S 5 -2 , and S 6 -2 -derive half to two-thirds of their sulfur atoms from elemental sulfur and the remainder from sulfide (Kamyshny et al, 2004;Amrani and Aizenshtat, 2004b).…”

Section: Proto-kerogen Sulfur In Sinking Particlesmentioning

confidence: 99%

Rapid organic matter sulfurization in sinking particles from the Cariaco Basin water column

Raven

Sessions

Adkins

et al. 2016

Geochimica et Cosmochimica Acta

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Organic matter (OM) burial in marine sediments is a potentially important control on global climate and the long-term redox state of the earth's surface. Still, we have only a limited understanding of the processes that stabilize OM and facilitate its preservation in the geologic record. Abiotic reactions with (poly)sulfides can enhance the preservation potential of OM, but for this process to be significant it needs to compete with OM remineralization, the majority of which occurs before sinking particles reach the sea floor. Here we investigate whether OM sulfurization occurs within sinking particles in the Cariaco Basin, a modern sulfidic marine environment with high rates of OM burial.Proto-kerogen in sinking particles is frequently more sulfur-rich and 34 S-depleted than expectations for biomass, with a composition that is difficult to explain by mixing with resuspended or terrigenous material. Instead, it appears that sulfur is being incorporated into OM on a timescale of days in sinking particles. The flux of this abiogenic organic S from particles is equivalent to approximately two-thirds of the total amount of protokerogen S at 10 cm depth in underlying sediments (ODP Core 1002B); after 6000 years of more gradual sulfurization reactions, potential water column sources are still equivalent to nearly half of the total proto-kerogen S in Cariaco sediments. Water column sulfurization is most extensive during periods of upwelling and high primary productivity 2 and appears to involve elemental S, possibly via polysulfides. This process has the potential to deliver large amounts of OM to the sediments by making it less available for remineralization, generating OM-rich deposits. It represents a potentially dynamic sink in the global carbon cycle that can respond to changes in environmental conditions, including the size and intensity of O 2 -depleted environments. Water column OM sulfurization could also have played a more significant role in the carbon cycle during ocean anoxic events, for example during the Cretaceous.

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“…22,23 Ex situ methods, while useful, do not provide the direct, in situ knowledge of the dissolved polysulfides that is required to determine where and when specific species form. Polysulfides can disproportionate with time, 24,25 and so capturing the species immediately after they form is * Electrochemical Society Student Member. z E-mail: mftoney@slac.stanford.edu critical to determining battery behavior.…”

mentioning

confidence: 99%

Operando Spectromicroscopy of Sulfur Species in Lithium-Sulfur Batteries

Miller

Kasse

Heath

et al. 2017

J. Electrochem. Soc.

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In this study, a novel cross-sectional battery cell was developed to characterize lithium-sulfur batteries using X-ray spectromicroscopy. Chemically sensitive X-ray maps were collected operando at energies relevant to the expected sulfur species and were used to correlate changes in sulfur species with electrochemistry. Significant changes in the sulfur/carbon composite electrode were observed from cycle to cycle including rearrangement of the elemental sulfur matrix and PEO 10 LiTFSI binder. Polysulfide concentration and area of spatial diffusion increased with cycling, indicating that some polysulfide dissolution is irreversible, leading to polysulfide shuttle. Fitting of the maps using standard sulfur and polysulfide XANES spectra indicated that upon subsequent discharge/charge cycles, the initial sulfur concentration was not fully recovered; polysulfides and lithium sulfide remained at the cathodes with higher order polysulfides as the primary species in the region of interest. Quantification of the polysulfide concentration across the electrolyte and electrode interfaces shows that the polysulfide concentration before the first discharge and after the third charge is constant within the electrolyte, but while cycling, a significant increase in polysulfides and a gradient toward the lithium metal anode forms. This chemically and spatially sensitive characterization and analysis provides a foundation for further operando spectromicroscopy of lithium-sulfur batteries. New "beyond lithium-ion" battery chemistries are essential to meet the increasing demand for long-lasting, high capacity energy storage in portable electronics and electric vehicles. Lithium-sulfur (Li-S) batteries are an attractive Li-ion alternative that provides large capacity (1672 mAh g −1 ) and energy density (2500 Wh kg −1 ) while also being low cost, earth-abundant, and lightweight.1-3 Li-S batteries have a unique chemistry that achieves high capacity via chemical transformation rather than Li intercalation. Elemental sulfur (S 8 ) is reduced through a series of soluble Li polysulfides (Li 2 S x , 2 ≤ x ≤ 8) to a final solid discharge product (Li 2 S), and the process is reversed upon charging. [4][5][6] However, Li-S suffers from unrealized theoretical capacity and rapid capacity fade due to loss processes that are not well-understood. 2,7 While many advances in electrode and electrolyte engineering have been made in an attempt mitigate these performance issues, 8-14 a gap remains in the mechanistic understanding of Li-S battery operation. Several mechanisms for reduced capacity and capacity fade have been proposed. Lithium polysulfides, which are necessary for operation, dissolve into the liquid electrolyte, remain dissolved, and "shuttle" between the electrodes rather than participating in the electrochemical reactions, decreasing the amount of active material available. 3,[15][16][17][18] Low sulfur utilization results in initially low capacity that then continues to decrease with subsequent cycles. [19][20][21] Batteries are spatiall...

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Equilibrium Distribution of Polysulfide Ions in Aqueous Solutions at 25 °C: A New Approach for the Study of Polysulfides' Equilibria

Cited by 198 publications

References 40 publications

Sulfur Cycling in an Iron Oxide-Dominated, Dynamic Marine Depositional System: The Argentine Continental Margin

Sulfur Cycling in an Iron Oxide-Dominated, Dynamic Marine Depositional System: The Argentine Continental Margin

Rapid organic matter sulfurization in sinking particles from the Cariaco Basin water column

Operando Spectromicroscopy of Sulfur Species in Lithium-Sulfur Batteries

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