Sulfate Reduction Research Articles

Intra/extracellular electron transfer and metagenomic analysis elucidated the roles of magnetic iron powder (Fe3O4) on mixotrophic denitrification system

Elemental iron provides a viable strategy to improve the denitrification efficiency by expediting electron transport. However, the roles of magnetic iron powder (Fe3O4) on mixotrophic denitrification remains unknown. In this study, the intra/extracellular electron transfer (IET/EET) and microbial metabolism mechanisms were explored in a Fe3O4-mediated sulfide-autotrophic and heterotrophic denitrification system. The results showed that Fe3O4 promoted the formation of dense clump structure with filamentous cross-linking in activated sludge. Fe3O4 could increase the coenzyme Q activity in IET and the content of free riboflavin and cytochrome c in EET. Metagenomic analysis indicated that denitrification, sulfide oxidation and sulfate reduction were the main pathways of nitrogen and sulfur metabolism, and the enriched denitrifying bacteria (Halomonas and Hypobacterium) and sulfur-oxidizing bacteria (Marinicella) could stably support nitrate removal. This study expands our understanding of the IET/EET during Fe3O4-mediated mixotrophic denitrification process, providing a novel insight for nitrogen removal from marine recirculating aquaculture wastewater.

Aggravation of Cd availability in the plastisphere of paddy soil

Soil plastisphere has attracted many concerns, however, its influence on cadmium (Cd) availability in paddy soil was still unclear. This study carried out batch microcosmic and bagging experiments to explore the influence of microplastic (MPs) on Cd availability in paddy soil under flooding conditions in the view of plastisphere. Results showed that the presence of MPs could act as plastisphere micro-environment. The bacterial community composition changed dramatically around the plastisphere compared with MPs-contaminated bulk soil and control soil. The relative abundance of Symbiobacteraceae, Rhodocyclaceae and Bryobacteraceae was improved in the plastisphere which contributed to the enhanced the reduction of Fe(III) and sulfate in flooding paddy soil. The higher content of Fe(II) and S content contributed to the enrichment of Cd in the plastisphere which aggravated Cd availability in paddy soil under flooding conditions. The partial least squares structure equation modeling results confirmed the presence of MPs in paddy soil could act as plastisphere which could change the bacterial community composition and improve the content Fe and S that was conductive to gather Cd in plastisphere. This study shed lights on the understanding of the role of plastisphere on Cd availability in paddy field ecosystem under flooding conditions.

Replacive IOCG systems in the Ossa Morena Zone (SW Iberia): The role of pre-existing ironstones as a geochemical trap

The central Ossa Morena Zone (SW Iberia) hosts a regionally extensive ironstone level interbedded with bimodal volcanic rocks, limestone and shale of Lower-Middle Cambrian age. The stratabound ironstone includes dominant magnetite and hematite with locally abundant chert and barite. It is interpreted as being (sub-)exhalative at or near the seafloor and formed during a rifting event that postdated the Cadomian orogeny. In some places, such as in the Las Herrerías deposit, the ironstone is irregularly replaced by a chalcopyrite-rich ore; the Cu-rich mineralization is accompanied by the pervasive phyllic alteration of the hosting siliciclastic sediments. The highest copper grades are found when the ironstone is crosscut by WNW-ESE-trending late-Variscan extensional brittle-ductile structures that are interpreted as the feeder channels for deep hydrothermal fluids. A similar nearby copper-rich mineralization (Pallares) is is likely controlled by the tectonic contact between limestone and pyrite-rich black shale.Sr-Nd whole-rock isotope geochemistry data suggests that the Sr in the ironstone (87Sr/86Sri ≈ 0.7088) is close to isotopic equilibrium with the local exhalative barite (0.7084–0.7086) and Cambrian seawater. The ironstone has a significantly more crustal εNd initial signature (<-1.8) than the coeval volcanic rocks (+5.2 to + 7.9). The younger sulfide mineralization inherited the Nd isotope composition of the ironstone but shows a significant enrichment in 87Sr (87Sr/86Sr > 0.7091) that is interpreted as related with the input of genetically different and more crustally-derived hydrothermal fluids.39Ar-40Ar dating of the phyllic alteration suggest that the copper mineralization was formed at ca. 332–330 My. These ages are coeval with those of small peraluminous granite intrusions that host Cu-Au vein-like mineralization and dated at 331.8 ± 1.6 Ma (LA ICPMS U-Pb zircon). Our interpretation is that the copper-rich mineralization at the Las Herrerías area is the distal expression of an intrusion-related hydrothermal system.Numerical modelling shows that ironstone is an effective trap for copper precipitation due to the large changes in pH and fO2 that take place when copper-bearing acid and reduced fluids react with the brittle ironstone. The precipitation of chalcopyrite, however, is controlled by the amount of available reduced sulfur in the ore trap. The δ34S values of the sulfides (+12.6 to + 21.6 ‰) suggest that the most likely source for the reduced sulfur is the thermogenic reduction of aqueous sulfate equilibrated with the exhalative barite (δ34S, +31.4 to + 35 ‰) with some minor input of reduced sulfur leached from the metasediments.This system could be considered as a variant of the IOCG clan. The formation of the ironstone and the copper mineralization, however, are separated by more than 200 My. Probably, many IOCG systems have a similar origin as Las Herrerías, with an ironstone being just a passive geochemical trap for the copper–gold mineralization.

Identifying the major metabolic potentials of microbial-driven carbon, nitrogen and sulfur cycling on stone cultural heritage worldwide

Microbial activities and biochemical reactions are responsible for the biodeterioration of stone cultural heritage, but information on microbial metabolic potentials remains elusive. Here we profiled microbial community signatures and its functional traits on stone cultural heritage from different climate zones globally using sequencing datasets available publicly. Bacterial community on stone cultural heritage shows a significant separation between BSk (cold semi-arid climate) and Cfb (temperate oceanic climate) with Aw (tropical savanna climate) as a transition region. Importantly, the ubiquity of ammonia oxidizers and nitrite oxidizers on stone cultural heritage under different climates supports the active production and accumulation of nitrates while ammonia/ammonium can be supplied by dinitrogen fixation and dissimilatory nitrate reduction to ammonium (DNRA), together with the hydrolysis of urea, arginine, formamide and cyanate. Sulfate accumulation on stone cultural heritage is mainly resulted from the microbial-driven transformation of organosulfur and thiosulfate, with little dissimilatory reduction of sulfate. Pseudorhodoplanes was identified and reported in elemental sulfur turnover for the first time. Notably, carbon sequestration via the reductive tricarboxylic acid (rTCA) cycle and an incomplete 3-hydroxypropionate/4-hydroxybutynate (HP/HB) cycle other than the Calvin Benson-Bassham (CBB) cycle is also significant on stone cultural heritage under relatively humid climate. These results advance our understanding of microbial metabolic potentials and their genetical partitioning patterns on stone cultural heritage of different climate zones globally.

Comparative Effects of Acetate- and Citrate-Based Dialysates on Dialysis Dose and Protein-Bound Uremic Toxins in Hemodiafiltration Patients: Exploring the Impact of Calcium and Magnesium Concentrations.

Modern hemodialysis employs weak acids as buffers to prevent bicarbonate precipitation with calcium or magnesium. Acetate, the most used acid, is linked to chronic inflammation and poor dialysis tolerance. Citrate has emerged as a potential alternative, though its effect on dialysis efficiency is not clear. This study aims to compare the efficacy of acetate- and citrate-based dialysates, focusing on protein-bound uremic toxins and dialysis doses. This single-center prospective crossover study includes prevalent patients participating in a thrice-weekly online hemodiafiltration program. Four dialysates were tested: two acetate-based (1.25 and 1.5 mmol/L calcium) and two citrate-based (1.5 mmol/L calcium with 0.5 and 0.75 mmol/L magnesium). Pre- and post-dialysis blood samples of eighteen patients were analyzed for urea, creatinine, p-cresyl sulfate, indoxyl sulfate, and albumin. Statistical significance was assessed using paired t-tests and repeated measures of ANOVA. There were no significant differences in dialysis dose (Kt), urea, creatinine, or indoxyl sulfate reduction ratios between acetate- and citrate-based dialysates. However, a significant decrease in the reduction ratio of p-cresyl sulfate was observed with the acetate dialysate containing 1.25 mmol/L calcium and the citrate dialysate with 0.5 mmol/L magnesium compared to the acetate dialysate containing 1.5 mmol/L calcium and the citrate dialysate with 0.75 mmol/L magnesium (51.56 ± 4.75 and 53.02 ± 4.52 vs. 65.25 ± 3.38 and 58.66 ± 4.16, p 0.007). No differences in dialysis dose were found between acetate- and citrate-based dialysates. However, citrate dialysates with lower calcium and magnesium concentrations may reduce the albumin displacement of p-cresyl sulfate. Further studies are needed to understand the observed differences and optimize the dialysate composition for the better clearance of protein-bound uremic toxins.

Using hydrochemistry and stable isotopes to character the karst water environment in a cave site, South China

For cave sites located within the seasonal fluctuation zone of groundwater, obtaining a comprehensive understanding of the hydrogeological conditions and hydrochemical environment is of utmost importance in assessing the preservation of cultural deposits. However, due to the heterogeneity of karst development, the hydrochemical environment of the overburden karst water-bearing unit may exhibit complex variations. In this study, the characteristics of the water environment in a foot cave system and its surrounding aquifer were investigated at the Zengpiyan site, employing hydrochemistry, hydrogen and oxygen isotope analysis, as well as sulfate isotope analysis, in conjunction with the hydrogeological background. Based on the exposure of the karst cave and the groundwater flow conditions, the water-bearing medium was categorized into five types. The aquifer exhibited either an oxidation or reduction condition, with a distinct "dissolved oxygen hole" observed in the saturated zone of the cave site. Ion concentration analysis revealed that the groundwater was influenced by the prior accumulation of cinders in the upstream region, leading to sulfate contamination within the foot cave system. However, during the groundwater movement from upstream to downstream, the attenuation rate of pollutants displayed significant variations. Notably, the sulfate content was unusually low within the site cave. Hydrogen and oxygen isotopes provided insights into the differing circulation and movement velocities of groundwater within the local environment. Additionally, sulfate isotopes confirmed the sources of sulfate and the occurrence of bacterial sulfate reduction within the site cave. Consequently, an environmental zoning classification was established based on these analyses. Although the concentration of dissolved ions appears low in the anoxic area, it does not imply a diminished environmental risk. Under reducing conditions, these pollutants can be converted into more aggressive gases, posing a substantial threat to the preservation environment of cave sites. Therefore, sufficient attention should be given to this aspect in order to ensure adequate protection.

Effect of Cd2+ and Cu2+ on Desulfovibrio vulgaris strain ATCC 7757: Insights from sulfur isotope fractionation

Microbial sulfate reduction (MSR) is the predominant microbial metabolic process involved in sulfur cycling in metal-sulfide mining areas. In this study, we investigated the effect of Cd2+ and Cu2+ on MSR driven by Desulfovibrio vulgaris strain ATCC 7757, determined the corresponding sulfur isotope compositions to establish a fundamental relationship between toxicity and isotope fractionation. Cd2+ did not cause significant cellular irrecoverable damage until concentrations exceeded 3.5 ppm, and the bacteria would enhance the transfer of SO42- to APS to ensure the bacterial growth. The repair of DNA damage caused by Cd2+ was a gradually stimulated process, which resulted in a tolerance period. Cu2+ inhibited MSR in a dose-dependent manner at concentrations below 1 ppm, and the bacterial growth significantly inhibited. When exposed to 1 ppm Cu2+ for 48h, ATCC 7757 might enhance the substrates transport to maintain its culturability through up-regulating genes encoding H+-transporting ATPase, ABC transporters and Protein export. Cd2+ had minimal impact on δ34Ssulfate, with an enrichment factor (34ε) ranging from -11.7‰ to -12.3‰. Conversely, Cu2+ significantly affected the δ34Ssulfate (34ε = -11.1‰ to -15.4‰), resulting in a substantial decrease in δ34Ssulfide, with the lowest value of δ34Ssulfide recorded as -18.8‰ (-11.5‰ for control group). The study demonstrated that sulfur isotope fractionation could indicate different toxicity mechanisms of heavy metal on ATCC 7757, aiding in the identification of environmental contamination caused by heavy metals.

Synthesis of various types of green biosorbents materials for removals of sulphates from contaminated water for better aquatic environments

Human and industrial activities pollute water resources with sulphur metal, endangering human health and ecosystems. Chemical precipitation and membrane filtration are expensive when treating large amounts of water, inefficient at low metal concentrations, and produce large amounts of toxic sludge and other products that must be disposed of waste water bio-sorption is eco-friendly and alternative. These methods are cheaper, more accessible, and reusable than conventional ones. This study investigates the bio-sorption of sulphur from contaminated water using neem leaf, custard apple leaf, mango tree leaf, orange peels, and banana peels biological waste materials. This work achieves 100 % removal efficiency. Biosorbents remove sulphates from contaminated water: custard leaves 100 % at 4gm, orange peels 40 % at 5gm, tea waste 50 % at 4gm, neem leaves 70 % at 5gm, and mango leaves 75 % at 5gm. The performances of biosorbents for removals of sulphates from water as follows: Custard leaves waste > Mango leaves > Neem leaves > Tea trash > Orange peels the sulphate reduction by biosorbents. The best biosorption occurred at basic pH 6.5, 3.7gm dosage, 90 min contact duration, 30 °C temperature, and 120 rpm agitation speed. The effects of contact time, agitation speed, adsorbent dosage, pH, and temperature are also examined. Before usage, biosorbents materials can be physically and chemically measured the changes. Regenerating and reusing bio-sorbent after sulphates removals makes the method cost-effective for removals of pollutants from water.

Re‐Evaluating Water Column Reoxygenation During the End Permian Mass Extinction

AbstractOcean anoxia is considered a key driver of the end‐Permian mass extinction (EPME). However, it is much debated whether there was an ocean reoxygenation phase during, and in the aftermath, of the EPME. Evidence for ocean reoxygenation is often inferred from the absence of framboidal pyrite in some boundary marine sediments (termed the “framboid gap”). To reconstruct ocean redox evolution across the EPME, we investigated the carbon isotopic, sedimentological, and redox records of the Ruichang and Ehtan sections in South China. These documents two negative δ13Ccarb excursions and the development of anoxia associated with deepening leading up to the Permian‐Triassic boundary. Above the level at which most siliceous organisms became extinct, pyrite framboid and iron proxies indicate that water column redox conditions were predominantly oxygenated but sporadically anoxic/ferruginous [non‐sulfidic, free Fe(II) in the water] at Ruichang, while ferruginous conditions were more widely developed at Ehtan. These contrasting redox states are characteristic of a dynamic ocean redox landscape in the extinction interval. The “framboid gap” is seen in strata deposited under both oxic and ferruginous conditions, suggesting that the availability of decomposable organic matter for sulfate reduction additionally controlled framboid genesis. Our data confirm that oxygenated conditions were developed in some deep water basins during the EPME.

Acidophilic sulphate-reducing bacteria: Diversity, ecophysiology, and applications.

Acidophilic sulphate-reducing bacteria (aSRB) are widespread anaerobic microorganisms that perform dissimilatory sulphate reduction and have key adaptations to tolerate acidic environments (pH <5.0), such as proton impermeability and Donnan potential. This diverse prokaryotic group is of interest from physiological, ecological, and applicational viewpoints. In this review, we summarize the interactions between aSRB and other microbial guilds, such as syntrophy, and their roles in the biogeochemical cycling of sulphur, iron, carbon, and other elements. We discuss the biotechnological applications of aSRB in treating acid mine drainage (AMD, pH <3), focusing on their ability to produce biogenic sulphide and precipitate metals, particularly in the context of utilizing microbial consortia instead of pure isolates. Metal sulphide nanoparticles recovered after AMD treatment have multiple potential technological uses, including in electronics and biomedicine, contributing to a cost-effective circular economy. The products of aSRB metabolisms, such as biominerals and isotopes, could also serve as biosignatures to understand ancient and extant microbial life in the universe. Overall, aSRB are active components of the sulphur and carbon cycles under acidic conditions, with potential natural and technological implications for the world around us.

Functional effects of subsidies and stressors on benthic microbial communities along freshwater to marine gradients.

Leaf litter in coastal wetlands lays the foundation for carbon storage, and the creation of coastal wetland soils. As climate change alters the biogeochemical conditions and macrophyte composition of coastal wetlands, a better understanding of the interactions between microbial communities, changing chemistry, and leaf litter is required to understand the dynamics of coastal litter breakdown in changing wetlands. Coastal wetlands are dynamic systems with shifting biogeochemical conditions, with both tidal and seasonal redox fluctuations, and marine subsidies to inland habitats. Here, we investigated gene expression associated with various microbial redox pathways to understand how changing conditions are affecting the benthic microbial communities responsible for litter breakdown in coastal wetlands. We performed a reciprocal transplant of leaf litter from four distinct plant species along freshwater-to-marine gradients in the Florida Coastal Everglades, tracking changes in environmental and litter biogeochemistry, as well as benthic microbial gene expression associated with varying redox conditions, carbon degradation, and phosphorus acquisition. Early litter breakdown varied primarily by species, with highest breakdown in coastal species, regardless of the site they were at during breakdown, while microbial gene expression showed a strong seasonal relationship between sulfate cycling and salinity, and was not correlated with breakdown rates. The effect of salinity is likely a combination of direct effects, and indirect effects from associated marine subsidies. We found a positive correlation between sulfate uptake and salinity during January with higher freshwater inputs to coastal areas. However, we found a peak of dissimilatory sulfate reduction at intermediate salinity during April when freshwater inputs to coastal sites are lower. The combination of these two results suggests that sulfate acquisition is limiting to microbes when freshwater inputs are high, but that when marine influence increases and sulfate becomes more available, dissimilatory sulfate reduction becomes a key microbial process. As marine influence in coastal wetlands increases with climate change, our study suggests that sulfate dynamics will become increasingly important to microbial communities colonizing decomposing leaf litter.

Photoelectron-promoted metabolism of sulphate-reducing microorganisms in substrate-depleted environments.

Sulphate-reducing microorganisms, or SRMs, are crucial to organic decomposition, the sulphur cycle, and the formation of pyrite. Despite their low energy-yielding metabolism and intense competition with other microorganisms, their ability to thrive in natural habitats often lacking sufficient substrates remains an enigma. This study delves into how Desulfovibrio desulfuricans G20, a representative SRM, utilizes photoelectrons from extracellular sphalerite (ZnS), a semiconducting mineral that often coexists with SRMs, for its metabolism and energy production. Batch experiments with sphalerite reveal that the initial rate and extent of sulphate reduction by G20 increased by 3.6 and 3.2 times respectively under light conditions compared to darkness, when lactate was not added. Analyses of microbial photoelectrochemical, transcriptomic, and metabolomic data suggest that in the absence of lactate, G20 extracts photoelectrons from extracellular sphalerite through cytochromes, nanowires, and electron shuttles. Genes encoding movement and biofilm formation are upregulated, suggesting that G20 might sense redox potential gradients and migrate towards sphalerite to acquire photoelectrons. This process enhances the intracellular electron transfer activity, sulphur metabolism, and ATP production of G20, which becomes dominant under conditions of carbon starvation and extends cell viability in such environments. This mechanism could be a vital strategy for SRMs to survive in energy-limited environments and contribute to sulphur cycling.

Sedimentary geochemistry in P-limited freshwater drained marshes (Charente-Maritime, France): original drivers for phosphorus mobilization

Phosphorus bioavailability is a major issue in aquatic environments, where it generally limits primary production. In this work, the analysis of the pore water and the solid phase of the sediment was carried out over a 9-month monitoring period between February 2020 and April 2021 in two drained marshes (Marans and Genouillé, France) distinct by their uses and management tools. Soluble reactive phosphorus (SRP) enrichment in the sediment was intimately controlled by iron oxide dissolution. The latter seemed highly controlled by seasonal nitrate inputs (winter and early spring) that favoured denitrification as a major benthic mineralization process promoting iron curtain development and stability. Following benthic mitigation of nitrate other anaerobic metabolisms developed such as iron dissolutive reduction promoting P recycling and planktic bioavailability. Surprisingly, sulphur cycle seemed to affect P dynamics, especially in the absence of nitrate. The absence of NO3- triggered high sulphate reduction rates in the two first centimeters depth, reaching -8.9E-03 ± 0.5E-03 and -5.0E-03 ± 0.2E-03 nmol cm-3 s-1 in August and July at Marans and Genouillé respectively. These values placed this process at higher rates than the denitrification (maximum in May at Marans with -5.0E-03 ± 1.1E-03 nmol cm-3 s-1) and reduced iron production (maximum in July at Genouillé with 0.5E-03 ± 0.1E-03 nmol cm-3 s-1). The rapidity with which process changes occur (monthly scale) testified to the dynamism of these systems. The similarity in geochemical patterns regarding NO3- pressure at both sites underlines the importance of diffuse pollution in coastal systems for nitrogen mitigation and phosphorus trapping. The results obtained in this study could lead to the development of a generalized diagenetic operating model for temperate systems with high agricultural pressure. This would enable to target management efforts to both optimize the purification function and limit eutrophication risks in these systems.

Coupled Effects of Paleofluid Evolution on Ultra-deep Microbialite Reservoir Modification: A case study of the upper Ediacaran Deng-2 Member within the Penglai area of central Sichuan Basin, SW China

Paleofluid-rock interaction results in the modification of the ultra-deep reservoir quality, but the coupling effects of the paleofluid evolution on reservoir quality modification are still underestimated. Here, the multi-stage dolomite cements have been studied by means of core observations, thin section identification, fluid inclusions, and in situ elements and isotopic analyses in order to reaveal the paleofluid evolution processes and their effects on the reservoir quality. The fibrous dolomite cement (FDC) and bladed dolomite cement (BDC) both have similar geochemical properties and homogenization temperature (Th) to the matrix dolostone. Subsequent early silicification occurs (QZ1). However, silt- to fine-sized crystalline dolomite cement (CD2) has higher concentration of Fe and medium rare earth element, more negative δ18O than for FDC and BDC, and 103.4 to 150.2 °C in Th. The first petroleum charge episode solid bitumen 1 (SB1) followed the CD2. The medium to coarse sized crystalline dolomite cement (CD3) is characterized by the higher Mn and lower Sr concentration than CD2, positive δEu anomaly, negative δ13C and δ18O, high 87Sr/86Sr ratio and 138.9 °C to 184.3 °C in Th. The solid bitumen 2 (SB2) occurs after CD3. Subsequently, the saddle dolomite (SD) has higher Fe and Mn concentration and lower Na and Sr than others cement, δEu positive anomaly, negative δ13C and δ18O, high 87Sr/86Sr ratio and 177.5 °C to 243.6 °C in Th. Eventually massive silicification (QZ2) took place. The FDC, BDC, QZ1 and SB1 formed in the early diagenetic stage and have little negative effect on the reservoir quality. But the CD2 and CD3 dramatically decreased the reservoir quality related to a quantity of hydrothermal fluids entrance in the mesodiagenetic stage along the strike-slip faults and the unconformity surface at top of the Deng-2 Member during the late stage of the Caledonian orogeny. The reservoir spaces were retained and enlarged during the late diagenetic stage when the peak petroleum charge occurred, massive silicification and thermochemical sulphate reduction took place with SB2, SD and QZ2 being formed. The research outcome may update our understanding on the retention mechanism and the insights for further hydrocarbon exploration of Precambrian ultra-deep microbial reservoirs.

Basin inversion, drifting and hyper-extension in the Central Atlantic Ocean and Maghrebian Tethys as fluid driving mechanisms for the superimposed base metal mineralization events in the Jbel Bou Dahar carbonate-hosted Pb-Zn-Ba deposits (High Atlas, Morocco)

The Early Jurassic Jbel Bou Dahar reef-bearing carbonate platform in the eastern High Atlas, Morocco, contains numerous carbonate-hosted and fault-controlled Pb-Zn-Ba deposits, prospects, and showings. Combined field, petrographic and geochemical data, including REE + Y analyses, stable (C-O-S), radiogenic (SrPb) and noble gas (He, Ne, Ar) isotopic compositions, record two temporally distinct metallogenic events. Both events are related to post-rifting and inversion of the inherited Mesozoic Atlas paleorift. The ore deposits are thought to have been formed during large-scale episodes of transtensional basin evolution, which developed as a far-field effect of the drifting of the Central Atlantic Ocean and Maghrebian Tethys while the basin continued to invert in response to the ongoing convergence between the African and the Eurasian plates. The paragenetically earliest Zn-rich ore was generated in a transtensional setting coincident with the hyper-extension of Maghrebian Tethys and the initial stages of drifting and formation of the Central Atlantic passive margin. Crustal extension and high heat fluxes provided by the hot upwelling mantle would have triggered buoyancy-driven convection of deeply sourced fluids and maturation of organic matter dispersed within the host carbonates to produce hydrocarbons within an extensional basin setting. These relatively reduced Zn-rich ore-forming fluids acquired metals mainly through protracted interaction with the country rocks including the underlying Triassic siliciclastic series and the granitic basement rocks. Regional ENE- to E-W-trending major faults would have acted as conduits for upward fluid flow and traps for Zn-Pb-Ba mineralization. Conversely, the late Pb-rich mineralization stage II is broadly constrained to have occurred between ca. 70 Ma and 10 Ma and is thought to be related to the transition from orogenic shortening (late Eocene) to post-orogenic crustal extension and exhumation (early Miocene) following Alpine orogenic collapse. Mixing of down-ward percolating meteoric fluids and ascending rock-buffered hydrothermal brines that had previously equilibrated with the radiogenic basement rocks along with thermochemical sulfate reduction of transported sulfate and/or thermal cracking, would have been the main ore-forming processes that controlled ore deposition. Given these fluid characteristics and geodynamic settings, the Jbel Bou Dahar ore field is classified as a hybrid carbonate-hosted Pb-Zn-Ba district formed by the juxtaposition of two deposit types rather than one progressively evolving mineralizing system. From an exploration standpoint, new delineation here of the two metallogenic events provides valuable exploration tools for further targeting PbZn and barite resources in the Atlas system of North Africa and other areas where similar orogenic belts experienced post-rift subsidence and basin inversion.

Chip−like high−entropy oxide catalysts enhance fast sulfur evolution reaction for long−life lithium−sulfur batteries

Many catalysts have shown excellent activity for the sulfur reduction reaction (SRR), but sluggish electrochemistry kinetics have hindered the development of lithium–sulfur batteries. It has been found that the activity of catalysts for the sulfur evolution reaction (SER) plays a crucial role in determining the overall reaction kinetics. To address this issue, the rational design of catalysts is crucial. Here, we proposed a popular rule to accelerate SER by using chip–like high–entropy perovskite oxide La0.7Sr0.3(Fe0.2Co0.2Ni0.2Zn0.2Mn0.2)O3-δ (LMO–HEO) as advanced electrocatalysts. The strong interaction between the adjacent metal atoms in different metals of LMO–HEO electrocatalysts could lead to a "cocktail effect", which not only greatly improved the catalytic capacity toward sulfur species, but also accelerated the oxidation reaction kinetics of Li2S. As a result, the S/La0.7Sr0.3(Fe0.2Co0.2Ni0.2Zn0.2Mn0.2)O3-δ cathodes delivered excellent cyclic stability with a capacity decay of only 0.025% after 1200 cycles at 2 C. This work has provided a rational design idea for new multifunctional electrocatalysts with high catalytic capacity.

Withdrawal: Steering Sulfur Reduction Pathways via Cisplatin Enables High Performance in Lithium‐Sulfur Batteries

Withdrawal: Steering Sulfur Reduction Pathways via Cisplatin Enables High Performance in Lithium‐Sulfur Batteries

EARLY DIAGENESIS GEOCHEMISTRY OF BOTTOM SEDIMENTS IN THE PLEISTOCENE CORE OF LAKE KOTOKEL (Eastern Baikal Region)

Chemical composition of bottom sediments and pore waters of organic-mineral sediments (sapropel) of Lake Kotokel (Eastern Baikal region) has been studied, based on long drilling cores, 14.5 and 16.5 m. A reduction type of diagenesis has been established, during which destruction of organic matter, transformation of the chemical composition of pore waters and the formation of authigenic minerals occur. Even in the uppermost intervals of sapropel, organic matter is being profoundly transformed and differs significantly in composition from that of bioproducers (plankton). The major role in diagenetic transformations of organic matter belongs to different physiological groups of microorganisms, primarily heterotrophic, amonifying and sulfate-reducing bacteria. During diagenesis, the basic chemical composition of pore waters (HCO3–, SO42–, Cl–, Ca2+, Mg2+, K+, Na+) changes, trace elements (Fe, Mn, Sr, Ba, Pb, As, Co, Ni) redistribute, concentrations of HCO3–, NH4+, PO43− and Si increase; this is caused by destruction of organic matter. In the process of bacterial sulfate reduction in pore waters, the concentration of SO42– decreases along the depth of the section, and in the sediment the proportion of reduced forms of sulfur increases and the isotopic composition of sulphur δ34S changes. Transformation of chemical composition of pore waters and the activity of microorganisms leads to the formation of authigenic pyrite, rhodochrosite, and barite.

Modeling and forecasting biogas production from anaerobic digestion process for sustainable resource energy recovery

Anaerobic digestion (AD) is one of the most extensively accepted processes for organic waste cleanup, and production of both bioenergy and organic fertilizer. Numerous mathematical models have been conceived for modeling the anaerobic process.In this study, a new modified dynamic mathematical model for the simulation of the biochemical and physicochemical processes involved in the AD process for biogas production was proposed. The model was validated, and a sensitivity analysis based on the OAT approach (one-at-a-time) was carried out as a screening technique to identify the most sensitive parameters. The model was developed by updating the bio-chemical framework and including more details concerning the physico-chemical process. The fraction XP was incorporated into the model as a particulate inert product arising from biomass decay (inoculum). New components were included to distinguish between the substrate and inoculum, and a surface-based kinetics was used to model the substrate disintegration. Additionally, the sulfate reduction process and hydrogen sulfide production have been included. The model was validated using data extracted from the literature. The model's ability to generate accurate predictions was testified using statistical metrics. The model exhibited excellent performance in forecasting the parameters related to the biogas process, with measurements falling within a reasonable error margin. The relative absolute error (rAE) and root mean square error (RMSE) were both less than 5 %, indicating a high ability of the current model in comparison with the literature. Additionally, the scatter index (SI) was below 10 %, and the Nash-Sutcliffe efficiency (NES) approached one, which affirms the model's accuracy and reliability. Finally, the model was applied to investigate the performances of the AD of food waste (FW). The findings of this study support the robustness of the developed model and its applicability as a virtual platform to evaluate the efficiency of the AD treatment and to forecast biogas production and its quality, CO2 emission, and energy potential across various organic solid waste types.

Geochronology, in-situ elements and sulfur isotopes of sulfides from the Songjiashan cobalt-iron deposit in the Zhongtiao mountains of North China Craton: Implications for cobalt occurrence and ore genesis

The Songjiashan Co-Fe deposit in the central part of the “Tongshan skylight” on the southeastern edge of the Zhongtiao Mountains is hosted by the volcanic-sedimentary rock series of the Paleoproterozoic Songjiashan Group. The spatial distribution of the orebodies is controlled by south-north trending rock units. Based on microscopic observations, the dominant ore minerals included magnetite, pyrite, chalcopyrite, carrollite, and linnaeite, while gangue minerals comprised quartz, calcite, sericite, and chlorite. Cobalt-iron ores had massive, banded, disseminated, and veinlet texture, and alteration of the host rocks included silicification, sericitization, pyritization, carbonation, and chloritization. Mineralization processes of the Songjiashan deposit were grouped into three periods: sedimentation, metamorphism, and hydrothermal. The Co concentrations in hydrothermal pyrite (Py-III) varied from 1.05 % to 3.75 %, with an average of 2.45 %. Cobalt in pyrite was homogeneously distributed and inversely correlated to Fe, indicating that Co isomorphically replaced Fe in pyrite. The characteristic Co/Ni ratio of pyrite varied greatly, ranging from 0.1 to 1000, reflecting various genetic types of sedimentation, metamorphism, and hydrothermal mineralization, with the main mineralization period primarily related to hydrothermal activities. Zircon U-Pb geochronology of the host rock and Re-Os isochron of Co-bearing pyrites indicate that Co mineralization mainly occurred at ∼2100 Ma. In-situ S isotopic analysis of sulfides reveals two peak δ34S values of 5–9 ‰ and 12–16 ‰. We interpret that the former value reflects the mixing of volcanic and marine sulfate sources, while the latter value is mainly artributted to marine sulfate sources. All δ34S values were lower than those of Proterozoic marine sulfates (15–20 ‰). Accordingly, we infer that thermochemical sulfate reduction plays a key role in marine sulfate reduction, and that the formation of Co-rich ore bodies in the Songjiashan deposit have undergone processes of initial sedimentation, metamorphism-deformation, and subsequent hydrothermal overprinting. Genetically, we suggest that the Songjiashan deposit belongs to a sedimentary-metamorphic hydrothermal superposition type Co-Fe deposit.