Oxidation Of Sulfides Research Articles

Biogeochemical stability of organic covers and mine wastes under climate change simulated mesocosms.

Mine environments in boreal and sub-boreal zones are expected to experience extreme weather events, increases in temperature, and shifts in precipitation patterns. Climate change impacts on geochemical stability of tailings contaminants and reclamation structures have been identified as important climate-related challenges to Canadian mining sector. Adapting current reclamation strategies for climate change will improve long-term efficiency and viability of mine tailings remediation/restoration strategies under a changing climate. Accordingly, mesocosm experiments were conducted to investigate associations of climate-driven shifts in microbial communities and functions with changes in the geochemistry of organic covers and underlying tailings. Our results show that warming appears to significantly reduce C:N of organic cover and promote infiltration of nitrogen into deeper, unoxidized strata of underlying tailings. We also observed an increase in the abundance of some nitrate reducers and sulfide oxidizers in microbial communities in underlying tailings. These results raise the concern that warming might trigger oxidation of sulfide minerals (linked to nitrate reduction) in deeper unoxidized strata where the oxygen has been eliminated. Therefore, it would be necessary to have monitoring programs to track functionality of covers in response to climate change conditions. These findings have implications for development of climate resilient mine tailings remediation/restoration strategies.

Rational Engineering of Nanostructured NiS/GO/PVA for Efficient Photocatalytic Degradation of Organic Pollutants

A novel nanocomposite film synthesized from an inexpensive and easily accessible polymer such as poly (vinyl alcohol) (PVA), which is coated with nickel sulfide (NiS) and graphene oxide (GO), was obtained from used drinking-water bottles. The produced coated film was examined as a potential photocatalyst film for wastewater treatment promotion in a batch system for the removal of methylene blue (MB) and tetracycline (TC) antibiotics. The experimental results show that the presence of GO significantly increases the photocatalytic efficiency of NiS, and the MB and TC degradation results proved that the incorporation of GO with NiS led to a more than one-and-a-half-fold increase in the removal percentage in comparison with the NiS/PVA-coated film. After 30 min of illumination using GO/NiS/PVA-coated film, the removal efficiency reached 86% for MB and 64% for TC. The photodegradation kinetic rate followed the pseudo-first-order rate. Furthermore, the response surface methodology (RSM) model was utilized to study and optimize several operating parameters. The ideal circumstances to achieve 91% elimination of MB are 12 mg L−1 MB initial concentration, two lamps, and an illumination time of 15 min; however, to achieve 85% TC removal, 11 mg L−1 TC initial concentration, two lamps, and a 45 min illumination time should be used. The fabricated nanocomposite photocatalyst film seems to have promise for use in water purification systems.

Dipyridyl-anderson-polyoxometalate built-in metal–organic frameworks for aerobic photooxidation

Two POM-MOFs Co-1 and Ni-1 were synthesized from pyridyl-Anderson-POM linker. When combined with [Ru(bpy)3]2+, Ru(bpy)3@Co-1 showed excellent photocatalytic performance in sulfide oxidation and oxidative coupling of benzylamines with good recyclability.

Factors controlling the water quality of rock glacier springs in European and American mountain ranges

Rock glaciers (RGs) provide significant water resources in mountain areas under climate change. Recent research has highlighted high concentrations of solutes including trace elements in RG-fed waters, with negative implications on water quality. Yet, sparse studies from a few locations hinder conclusions about the main drivers of solute export from RGs. Here, in an unprecedented effort, we collected published and unpublished data on rock glacier hydrochemistry around the globe. We considered 201 RG springs from mountain ranges across Europe, North and South America, using a combination of machine learning, multivariate and univariate analyses, and geochemical modeling. We found that 35 % of springs issuing from intact RGs (containing internal ice) have water quality below drinking water standards, compared to 5 % of springs connected to relict RGs (without internal ice). The interaction of ice and bedrock lithology is responsible for solute concentrations in RG springs. Indeed, we found higher concentrations of sulfate and trace elements in springs sourcing from intact RGs compared to water originating from relict RGs, mostly in specific lithological settings. Enhanced sulfide oxidation in intact RGs is responsible for the elevated trace element concentrations. Challenges for water management may arise in mountain catchments rich in intact RGs, and where the predisposing geology would make these areas geochemical RG hotspots. Our work represents a first comprehensive attempt to identify the main drivers of solute concentrations in RG waters.

Inhibitors of NLRP3 Inflammasome Formation: A Cardioprotective Role for the Gasotransmitters Carbon Monoxide, Nitric Oxide, and Hydrogen Sulphide in Acute Myocardial Infarction.

Myocardial ischaemia reperfusion injury (IRI) occurring from acute coronary artery disease or cardiac surgical interventions such as bypass surgery can result in myocardial dysfunction, presenting as, myocardial "stunning", arrhythmias, infarction, and adverse cardiac remodelling, and may lead to both a systemic and a localised inflammatory response. This localised cardiac inflammatory response is regulated through the nucleotide-binding oligomerisation domain (NACHT), leucine-rich repeat (LRR)-containing protein family pyrin domain (PYD)-3 (NLRP3) inflammasome, a multimeric structure whose components are present within both cardiomyocytes and in cardiac fibroblasts. The NLRP3 inflammasome is activated via numerous danger signals produced by IRI and is central to the resultant innate immune response. Inhibition of this inherent inflammatory response has been shown to protect the myocardium and stop the occurrence of the systemic inflammatory response syndrome following the re-establishment of cardiac circulation. Therapies to prevent NLRP3 inflammasome formation in the clinic are currently lacking, and therefore, new pharmacotherapies are required. This review will highlight the role of the NLRP3 inflammasome within the myocardium during IRI and will examine the therapeutic value of inflammasome inhibition with particular attention to carbon monoxide, nitric oxide, and hydrogen sulphide as potential pharmacological inhibitors of NLRP3 inflammasome activation.

Persulfide Dioxygenase from Pseudomonas aeruginosa unveils a novel crosstalk mechanism between the bioenergetically-relevant gaseous signaling molecules nitric oxide and hydrogen sulfide

Persulfide Dioxygenase from Pseudomonas aeruginosa unveils a novel crosstalk mechanism between the bioenergetically-relevant gaseous signaling molecules nitric oxide and hydrogen sulfide

Hydrogen sulfide oxidation by sulfide:quinone reductase supports mitochondrial ATP production when complex I is inhibited

Hydrogen sulfide oxidation by sulfide:quinone reductase supports mitochondrial ATP production when complex I is inhibited

Synergy between NiWO4 and chitosan for the development of catalysts for sulfide oxidation

In this work, catalysts based on composite films composed by chitosan with disordered NiWO4 (10, 20, and 40 % w/w) were synthesized for their application in the oxidation of sulfides to sulfones. The catalysts were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), optical profilometry, and contact angle measurements. Optimization of the catalytic conditions was performed using thioanisole as the standard molecule, resulting in optimal conditions of 50°C, 1 h, 10 mg catalyst loading, 8 equivalents of H2O2 as oxidant, and acetonitrile as solvent. The results obtained were superior to those with crystalline NiWO4 (highly ordered), highlighting the crystallinity of the system as a key factor in the development of new catalysts. The catalyst exhibited high stability over successive catalytic cycles, and scaling up to 50 times was achieved. Additionally, the reaction scope showed good conversion for a variety of different sulfides, indicating the robustness of the catalyst. Analysis of the catalytic mechanism through scavenger tests and spectroscopic probes revealed that reactive oxygen species (ROS) are responsible for the oxidation of sulfides to sulfones. Furthermore, it was observed that the synergy between NiWO4 and chitosan is crucial for the effective generation of ROS in this reaction.

Green Molecular Reactor Boosting the Photocatalytic Aerobic Oxidation of Sulfides in Clean Solvent

AbstractThe synthesis of sulfoxides has long attracted considerable interest due to their pivotal role in organic synthesis, pharmaceutics and environmental protection. Oxidation of the corresponding sulfides is recognized as the most effective strategy. Traditional oxidation methods, however, fall short of the growing demands of green chemistry. Photocatalytic aerobic oxidation has thus garnered attention, employing the greenest and most sustainable oxidants—oxygen or air—and sunlight as the energy source. Nevertheless, these reactions are typically conducted in potentially pollutive organic solvents rather than in the greenest solvent, water. To facilitate this organic transformation in aqueous phase, molecular reactors that can encapsulate reactants within their confined pores and facilitate photocatalytic reactions have been developed recently. This Concept article summarizes the development of molecular reactors for the photocatalytic oxidation of sulfides and provides perspectives for the design and construction of effective photocatalytic molecular reactors.

NO- and H2S- releasing nanomaterials: A crosstalk signaling pathway in cancer

The gasotransmitters nitric oxide (NO) and hydrogen sulfide (H2S) play important roles not only in maintaining physiological functions, but also in pathological conditions and events. Importantly, these molecules show a complex interplay in cancer biology, demonstrating both tumor-promoting and anti-tumor activities depending on their concentration, flux, and the environmental redox state. Additionally, various cell types respond differently to NO and H2S. These gasotransmitters can be synergistically combined with traditional anticancer treatments such as radiotherapy, immunotherapy, chemotherapy, and phototherapy. Notably, NO, and more recently H2S, have been shown to reverse multidrug resistance. Nanomaterials to deliver NO donors and, to a lesser extent, H2S donors, have emerged as a promising approach for targeted delivery of these gasotransmitters. Nanotechnology has advanced the delivery of anticancer drugs, enhancing efficiency and reducing side effects on non-cancerous cells. This review highlights recent progress in the design of NO and H2S-releasing nanomaterials for anticancer effects. It also explores the interactions between NO and H2S, which are crucial for developing combined therapies and nanomedicines with minimal side effects.

Wastewater Treatment with Bacterial Representatives of the Thiothrix Morphotype.

Bacteria of the Thiothrix morphotype, comprising the genera Thiothrix, Thiolinea and Thiofilum, are frequently encountered in domestic and industrial wastewater treatment systems, but they are usually not clearly differentiated due to the marked similarity in their morphologies. Methods ranging from light microscopy, FISH and PCR to modern high-throughput sequencing are used to identify them. The development of these bacteria in wastewater treatment systems has both advantages and disadvantages. On the one hand, the explosive growth of these bacteria can lead to activated sludge bulking or clogging of the treatment system's membranes, with a consequent decrease in the water treatment efficiency. On the other hand, members of the Thiothrix morphotype can improve the quality of granular sludge and increase the water treatment efficiency. This may be due to their capacity for sulfide oxidation, denitrification combined with the oxidation of reduced sulfur compounds, enhanced biological phosphate removal and possibly denitrifying phosphate removal. The recently obtained pangenome of the genus Thiothrix allows the explanation, at the genomic level, of the experimental results of various studies. Moreover, this review summarizes the data on the factors affecting the proliferation of representatives of the Thiothrix morphotype.

Identification of Anthropogenic and Natural Inputs of Sulfate into River System of Carbonate Zn-Pb Mining Area in Southwest China: Evidence from Hydrochemical Composition, δ34SSO4 and δ18OSO4

The release of pollutants from lead-zinc mining areas poses a significant threat to the environment, making pollution tracing crucial for environmental protection. However, the complexity of carbonate mining areas makes tracing these pollutants challenging. This study used δ34SSO4 and δ18OSO4 isotopes combined with the Stable Isotope Mixing Models in R (SIMMR) to assess anthropogenic sulfate sources in the Daliangzi mining area. The river water types were mainly Ca2+-Mg2+-HCO3−, and SO42−, which are significantly influenced by dolomite dissolution. The δ34SSO4 values ranged from 6.47‰ to 17.96‰ and the δ18OSO4 values ranged from −5.66‰ to 13.98‰. The SIMMR results showed that evaporite dissolution in tributaries, driven by gypsum, contributed 31% of sulfate, while sulfide oxidation, sewage, and atmospheric deposition contributed 19%, 18%, and 24%, respectively. The tailings pond near Xincha Creek has a higher sulfate release potential than the processing plant near Cha Creek. In the mainstream, sulfide oxidation contributed 25%, primarily from mine drainage. Anthropogenic sources, including sulfide oxidation, fertilizers, and sewage, made up about 50% of the total sulfate, with sulfide oxidation accounting for half of this input. The strong correlation between the Zn and SO42− concentrations (R2 = 0.82) and between the Zn and the contribution from the sulfide oxidation (R2 = 0.67) indicates their co-release during sulfide oxidation, making SO42− a proxy for tracing Zn sources. This study highlights the utility of δ34SSO4 and δ18OSO4 with SIMMR in tracing anthropogenic inputs and underscores the significant impact of mining on river systems and the sulfur cycle.

Oxygen Substitution to Enhance Chemo-Mechanical Stability at the Cathode-Sulfide Electrolyte Interface in All-Solid-State Batteries.

The high interface resistance at the cathode-sulfide electrolyte interface is still a crucial drawback in an all-solid-state battery, unlike the initial expectation that the all-solid-state interface would enhance electrochemical stability by reducing side reactions at the interface. In this study, we examined the fundamental mechanism of unexpected reactions at the interface of LiNi0.8Co0.1Mn0.1O2 (NCM811) and argyrodite (Li6PS5Br0.5Cl0.5, LPSBC) sulfide solid electrolytes based on the combined method of multiscale simulations and electrochemical experiments. The high interface resistance originates from the formation of a passivating layer at the interface combined with irregular atomic and electronic structures, Li depletion, mutual element exchange, and mechanical contact loss between the oxide cathode and sulfide solid electrolyte. We also confirmed that these side reactions were suppressed by O substitutions to sulfide solid electrolyte (LPSOBC), and then the chemo-mechanical stability of the all-solid battery was enhanced by alleviating the side reactions at the interface. This study provides rational insights into the design of an interface for all-solid-state batteries.

Oxidation of nickel concentrates in simulated reaction shaft conditions of the flash smelter

The suspension oxidation of nickel sulfide concentrates in flash smelting conditions was studied using a laboratory-scale laminar flow furnace. The effects of temperature (800–1100 °C) and oxygen concentration (40–85 vol%) in the process gas were investigated. The surface morphology and mineralogical compositions of samples were examined using scanning electron microscopy equipped with energy-dispersive X-ray spectrometry. The sulfur removal from concentrates was determined using chemical analysis assuming iron as a non-volatile component. It was found that ignition of the nickel concentrates started at a temperature below 800 °C. The sulfur removal from the sieved concentrates increased with increasing temperature. The oxidation was initiated with preferential oxidation of iron in sulfides forming an iron oxide-rich scale on sulfidic core.

An Examination of Chemical Tools for Hydrogen Selenide Donation and Detection.

Hydrogen selenide (H2Se) is an emerging biomolecule of interest with similar properties to that of other gaseous signaling molecules (i.e., gasotransmitters that include nitric oxide, carbon monoxide, and hydrogen sulfide). H2Se is enzymatically generated in humans where it serves as a key metabolic intermediate in the production of selenoproteins and other selenium-containing biomolecules. However, beyond its participation in biosynthetic pathways, its involvement in cellular signaling or other biological mechanisms remains unclear. To uncover its true biological significance, H2Se-specific chemical tools capable of functioning under physiological conditions are required but lacking in comparison to those that exist for other gasotransmitters. Recently, researchers have begun to fill this unmet need by developing new H2Se-releasing compounds, along with pioneering methods for selenide detection and quantification. In combination, the chemical tools highlighted in this review have the potential to spark groundbreaking explorations into the chemical biology of H2Se, which may lead to its branding as the fourth official gasotransmitter.

Synthesis and Characterization of Polycarbonate/Polystyren/Polyethylene Oxide/Zinc Sulfide Nanocomposites: Gamma Ray Induced Changes in their Optical and Color Properties

Amorphous polycarbonate (PC), amorphous polystyrene (PS), semicrystalline polyethylene oxide (PEO) and zinc sulfide (ZnS) nanoparticles (NP) were used to fabricate PC/PS/PEO/ZnS nanocomposite (NC) films. We believe that this study is novel in the area of the effect of γ ray radiation on such NC. The synthesized ZnS NP had an average particle size of 18 nm, as indicated from the Rietveld refinement of the X-ray diffraction (XRD) scans. Samples of the PC/PS/PEO/ZnS NC films were irradiated with γ ray doses ranging from 20 to 180 kGy. UV-vis spectroscopy and the International Commission on Illumination (CIE) color changes technique were used to investigate the resulting effects of the γ ray irradiation on the optical and color properties of the prepared films. The light absorbance of the NC films increased as it was irradiated with the γ ray doses up to 180 kGy, the maximum dose used. The increase in absorbance was associated with a decrease in the direct bandgap from 5.88 to 4.92 eV, and an increase of Urbach energy from 0.43 to 0.81 eV. This was attributed to the dominance of chain crosslinks. The γ ray effects on the absorbance, extinction coefficient, refractive index and optical conductivity of the NC films were studied. The modifications in the optical properties indicated that the γ radiation is a useful tool that allows the application of the resulting PC/PS/PEO/ZnS NC films in optoelectronic devices. Furthermore, the color differences between the pristine and irradiated films were evaluated using the CIE color differences technique. The pristine film was uncolored but showed significant color changes when irradiated with γ radiation up to 180 kGy, the maximum dose used.

Synergistic Electrocatalysis and Spatial Nanoconfinement to Accelerate Sulfur Conversion Kinetics in Aqueous Zn−S Battery

AbstractAqueous zinc batteries based on the conversion‐type sulfur cathodes are promising in energy storage system due to the high theoretical energy density, low cost, and good safety. However, the multi‐electron solid‐state intermediate conversion reaction of sulfur cathodes generally possess sluggish kinetics, which leads to lower discharge voltage and inefficient sulfur utilization, thus suppressing the practical energy density. Herein, sulfur nanoparticles derived from metal–organic frameworks confined in situ within electrospun fibers derived sulfur and nitrogen co‐doped carbon nanofibers (S@S,N−CNF) composite, which possesses yolk–shell S@C nanostructure, is fabricated through successive sulfidation, pyrolysis, and sulfide oxidation processes, and served as a high‐performance cathode material for Zn−S battery. The S and N dopants on carbon can collectively catalyse sulfur reduction reaction (SRR) by lowering energy barrier and accelerating kinetics to increase discharge voltage and specific capacity. Meanwhile, the yolk–shell S@C structure with spatially confined S nanoparticle yolks is beneficial to improve charge transfer and lower activation energy, thus further expediting SRR kinetics. Furthermore, extensive density functional theory (DFT) calculations reveal that S and N dual‐doping can thermodynamically and dynamically reduce the energy barrier of rate‐determining step (i.e., the transformation of *ZnS4 into *ZnS2) for the overall SRR, thereby significantly accelerating SRR kinetics.

Synergistic Electrocatalysis and Spatial Nanoconfinement to Accelerate Sulfur Conversion Kinetics in Aqueous Zn-S Battery.

Aqueous zinc batteries based on the conversion-type sulfur cathodes are promising in energy storage system due to the high theoretical energy density, low cost, and good safety. However, the multi-electron solid-state intermediate conversion reaction of sulfur cathodes generally possess sluggish kinetics, which leads to lower discharge voltage and inefficient sulfur utilization, thus suppressing the practical energy density. Herein, sulfur nanoparticles derived from metal-organic frameworks confined in situ within electrospun fibers derived sulfur and nitrogen co-doped carbon nanofibers (S@S,N-CNF) composite, which possesses yolk-shell S@C nanostructure, is fabricated through successive sulfidation, pyrolysis, and sulfide oxidation processes, and served as a high-performance cathode material for Zn-S battery. The S and N dopants on carbon can collectively catalyse sulfur reduction reaction (SRR) by lowering energy barrier and accelerating kinetics to increase discharge voltage and specific capacity. Meanwhile, the yolk-shell S@C structure with spatially confined S nanoparticle yolks is beneficial to improve charge transfer and lower activation energy, thus further expediting SRR kinetics. Furthermore, extensive density functional theory (DFT) calculations reveal that S and N dual-doping can thermodynamically and dynamically reduce the energy barrier of rate-determining step (i.e., the transformation of *ZnS4 into *ZnS2) for the overall SRR, thereby significantly accelerating SRR kinetics.

Tracing sulfate sources in a tropical agricultural catchment with a stable isotope Bayesian mixing model

Sulfate (SO42−) is an essential anion in drinking water and a vital macronutrient for plant growth. However, elevated sulfate levels can impact ecosystem or human health and could be an important indicator of acid rock drainage or pollution. Therefore, monitoring SO42− sources and transport is important for water quality assessments. This study focused on exploring the sources and transformations of SO42− as well as estimating the proportional contribution of the potential SO42− pollutant sources to groundwater and surface water in a tropical river basin, the Densu River Basin. The study used major ions combined with stable sulfur and oxygen isotope compositions and a Bayesian isotope mixing model, MixSIAR. The major ion characteristics indicate that SO42− concentrations remain stable throughout the rainy and dry seasons but originate from diverse sources. The multi-isotope model (δ34SSO4, δ18OSO4) identified four potential SO42− sources: detergent, precipitation, sewage, and sulfate fertilizer. However, the δ34SSO4 and δ18OSO4 values of the fertilizer source signatures overlapped with those of precipitation and sewage. Nevertheless, the contributions from each source were disentangled using the MixSIAR model, which revealed sewage as the most dominant SO42− pollutant in the Densu Basin, accounting for ~47 % of sulfate in groundwater and ~ 56 % of sulfate in surface water. Sulfate fertilizer (~33 %) was the second most important source after sewage for groundwater, while detergent (~23 %) was the second most important source for surface water. The redox processes of bacterial sulfate reduction and sulfide oxidation were determined to have a minimal impact on the sulfur isotope fractionation within the basin. This study highlights the benefits of combining major ions, sulfur isotopes and the MixSIAR model for identifying sources of sulfate. This approach accounts for uncertainties in source contributions which allows for more robust and reliable apportionment of sulfate sources. The study emphasizes the need for effective waste management and pollution control measures to protect water quality and provides vital guidelines on how to partition sulfate sources on a large catchment scale and evidence for making pollution management decisions on water resources.

Expanding the Use of Benzothioxanthene Imides to Photochemistry: Eco-Friendly Aerobic Oxidation of Sulfides to Sulfoxides.

The sulfoxide moiety is one of the most commonly utilized groups in pharmaceutical and industrial chemistry. The need for sustainability and easy accessibility to sulfoxide moieties is deemed necessary, due to its ubiquity in natural products and potentially pharmaceutically active compounds. In this context, we report herein a sustainable, aerobic and environmentally friendly photochemical protocol based on the use of a benzothioxathene imide as the photocatalyst to selectively oxidize sulfides under mild irradiation (456 nm), in very low catalyst loading (0.01 mol %) and on water. In addition, to demonstrate the compatibility of our protocol with wide scope of substrates, the latter was successfully applied to the synthesis of the biologically-active Sulforaphane and Modafinil.