Search Results (5,455)

Hydrogen sulfide (H₂S) removal with simultaneous sulfur recovery is essential for natural gas, refinery, and biogas processing because of the toxicity and corrosivity of H₂S. However, conventional Claus sulfur recovery is energy-intensive, operates at high temperatures, and requires multiple processing units, creating a need for efficient low-temperature alternatives. In this study, the redox-active ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate ([BMIM][FeCl₄]) was investigated as both an absorbent and catalyst for the direct oxidation of H₂S to elemental sulfur. Experiments were conducted in a laboratory-scale semi-batch single-bubble reactor at 25–100 °C and 500–3000 ppm H₂S. Under the optimum operating conditions, H₂S conversion exceeded 99%, with removal efficiency increasing from 95.0% at 25 °C to 99.1% at 100 °C within 60 min. Kinetic analysis revealed first-order reaction kinetics with respect to H₂S and Fe(III), with apparent rate constants increasing from 0.0506 to 0.0636 min⁻¹ over the investigated temperature range and an apparent activation energy of 2.78 kJ mol⁻¹. Hatta number analysis confirmed that the process operated predominantly in the reaction-controlled regime. Raman spectroscopy showed the attenuation of [FeCl₄]⁻ vibrational bands together with the appearance of characteristic S₈ bands, while X-ray diffraction (XRD) verified the formation of crystalline elemental sulfur. CHNS analysis provided complementary elemental evidence for sulfur formation. The ionic liquid exhibited excellent thermal stability (>320 °C) and retained 92–95% of its initial activity after repeated regeneration cycles. These findings demonstrate that [BMIM][FeCl₄] effectively integrates H₂S absorption and catalytic oxidation within a single liquid phase, providing a promising low-temperature and energy-efficient alternative to conventional sulfur recovery technologies. Full article

The commercialization of sulfide-based all-solid-state batteries (ASSBs) is severely limited by the interfacial degradation between layered oxide cathodes and sulfide solid electrolytes, resulting in electrolyte decomposition, impedance growth, and rapid capacity fading. Herein, we propose lithium dihydrogen phosphate (LiH₂PO₄, LDP) as a low-cost polyanionic interphase precursor to regulate the cathode–electrolyte interface. A uniform LDP coating was deposited onto polycrystalline NCM622 particles, producing a continuous 40-nm-thick phosphate layer. Although the LDP-coated electrode exhibited a higher initial interfacial resistance than the bare cathode, electrochemical analyses revealed a capacity retention of 94.1% after 100 cycles, compared with 73.9% for the uncoated electrode. X-ray photoelectron spectroscopy demonstrated that LiH₂PO₄ is not chemically inert toward Li₆PS₅Cl but undergoes a controlled initial reaction with sulfur-deficient species to generate a phosphate-rich artificial interphase while suppressing the unstable P–[S]_n–P species. This interphase rapidly reaches chemical equilibrium, suppressing sulfur precipitation, SO_x formation, and subsequent electrolyte decomposition. Cross-sectional STEM–EDS and focused ion beam analyses revealed that the artificial phosphate interphase inhibited elemental interdiffusion, suppressed chemical mixing, and preserved mechanical contact during prolonged cycling. These findings demonstrate that the electrochemical penalty associated with the initial formation of the LDP interphase represents the necessary cost of constructing a chemically stable interface rather than a degradation process. This study introduces a new interfacial design strategy based on chemically active sacrificial interphase precursors, providing an alternative to conventional inert oxide coatings for realizing long-term stable sulfide-based all-solid-state batteries. Full article

The Chimkent Phosphorus Plant (CPP) (operational 1966–1996) was the flagship enterprise of the chemical industry in Soviet Kazakhstan. We wished to characterize historical occupational exposures, document health outcomes, and identify contemporary public health implications associated with a major but now defunct manufacturing enterprise. We analyzed archival data for the CPP from the Turkistan Oblast State Archive of Kazakhstan together with data from contemporaneous Soviet biomedical journal publications and doctoral dissertations. In the first years of production (1966–1970), multiple process steps generated emissions that exceeded the then-current occupational exposure limit (OEL) of 5 mg/m³ for generic total dust. Processes included: the drying and crushing process (peak exposure, 1080 mg/m³); agglomeration (peak, 700 mg/m³); and tripolyphosphate processing (peak, 1170 mg/m³). Exposures to toxic gases were also elevated (chlorine gas, 13 ppm (OEL 0.3 ppm) and hydrogen sulfide, 66 ppm (OEL 6.5 ppm)). Adverse health effects were endemic. From 1968 to 1992, annual reports documented a total of 298 cases of “chronic phosphorus intoxication.” Contemporary public sources emphasized the manufacturing process and economic importance of CPP. The story of the rise and fall of this massive state-owned enterprise carries wider policy implications for effectively protecting occupational health and safety. Full article

Engineered nanoparticles (ENPs) are being used with increasing frequency in industrial and consumer products across applications in industry, agriculture, ecology, and biomedicine. The unique physicochemical characteristics that make nanoparticles desirable in product design also affect their fate in the environment, interactions with living systems, and mechanisms of toxicity. Traditional testing methods and toxicological paradigms based on dissolved chemicals are poorly suited to understand ENP risks, primarily due to their small size, large SA:Vs, increased reactivity, and a surface chemistry that can be tuned during synthesis. Nanoparticle toxicity is dependent on complex relationships between particle characteristics, transformations in the environment, resulting exposure scenarios, and biological effects. Here we review ENP toxicity across a property → transformation → exposure → toxicity continuum, with a focus on how particle properties affect environmental and biological transformations relevant to toxicity. Properties such as size, shape, surface chemistry, dissolution, redox activity, and aggregation propensity are reviewed with respect to effects on transport and bioavailability, cellular uptake, biodistribution, and toxicity mechanisms. Transformations including aggregation, oxidation, dissolution/sulfidation, aging and eco-corona formation are discussed with regard to impacts on exposure and risk. Finally, major mechanisms of toxicity including oxidative stress, ion toxicity, membrane damage, inflammation, and genotoxicity are discussed with regard to nano–bio interactions. Analytical challenges associated with studying ENPs, shortcomings of the current risk assessment methods, and emerging Safe-by-Design approaches are also reviewed. Furthermore, connections between the fields of engineered nanoparticle toxicology and microplastics/nanoplastics are discussed, with particular focus on overlapping physicochemical properties, transformations, exposures, and biological mechanisms. Full article

This study evaluated nano-iron sulfide (nFeS) as an iron source for bioavailability, biocompatibility, and tolerance in broilers. Broilers (Arbor Acres; males; initial body weight: 43.0 ± 0.4 g) were allocated between five diets: an iron-deficient basal diet (ID), or a basal diet with 80 mg Fe/kg as FeSO₄; or 20, 40, or 80 mg Fe/kg as nFeS. The results showed that nFeS treatments (40, 80 mg/kg) improved average daily gain and feed conversion rates compared to ID and showed comparable or even superior effects relative to FeSO₄ on growth performance within 1–21 days (p < 0.05). nFeS improved whole-blood hemoglobin (Hb) content and packed cell volume (PCV) percentages at day 21, while increasing serum SOD and GSH-Px activities at day 42. nFeS (40, 80 mg/kg) had or tended to deposit higher iron content in the liver, spleen, duodenum and serum than the FeSO₄ groups. nFeS significantly increased breast meat lightness and redness compared with ID (p < 0.05) and showed comparable effects on postmortem pH, drip loss, and shear force relative to FeSO₄. nFeS reshaped the microbial composition in the jejunum and cecum, particularly enriching the abundance of beneficial bacteria such as Lactobacillus in the jejunum. At a dose of up to 400 mg/kg, nFeS revealed no negative effects in broilers. In conclusion, nFeS is an effective iron supplement with high bioavailability and comparability, with additional benefits in shaping intestinal microbiota. Full article

The Galinge deposit in East Kunlun, China is a large Fe-polymetallic skarn system with a significant by-product, Co, but the respective roles of magmatism, skarn evolution, and wall rock interaction in Co enrichment remain incompletely understood. We integrate zircon and garnet U–Pb geochronology, zircon Lu–Hf isotopes and trace elements, whole-rock geochemistry, and SEM-EDS and EPMA mineral chemistry. Granodiorite and diorite porphyry yield zircon U–Pb ages of 230.09 ± 0.91 Ma and 229.4 ± 1.3 Ma, respectively, whereas skarn garnet yields 224.4 ± 9.3 Ma, placing intrusion and skarn formation within a Late Triassic magmatic–hydrothermal system. Both suites are metaluminous, LREE-enriched, and Nb–Ta–Ti-depleted; zircon ε_Hf(t) values of −9.4 to −1.8 indicate the predominant reworking of older crustal material with variable input from a more radiogenic component. Strictly screened Ti-in-zircon temperatures and lattice strain Ce anomalies yield median apparent ΔFMQ values of +3.36 for granodiorite and +3.04 for diorite porphyry, indicating comparably oxidized magmatic conditions. The analyzed intrusions contain 2.12–13.4 ppm Co, whereas cobaltite and Co-bearing arsenopyrite contain 32.83–34.14 wt% and 0.38–4.53 wt% Co, respectively. Spatial and paragenetic relations place Co enrichment after magnetite deposition, during an early sulfide-stage hydrothermal sulfarsenide event within the skarn system. We infer that Late Triassic intrusions supplied heat, fluids, and ligands, whereas structural focusing and cooling, coupled with carbonate wall rock reactions and a reduction in carbonaceous or Fe²⁺-bearing domains, promoted As–S-rich Co precipitation; the leaching of intermediate–mafic wall rocks may have supplemented the Co inventory. Full article

To address cathode passivation, performance deterioration, and toxic stress during the removal of hexavalent chromium [Cr(VI)] in biocathode microbial fuel cells (MFCs), this study constructed nanomaterial-hybridized biocathodes to improve electricity generation and Cr(VI) removal in MFCs. Reduced graphene oxide (rGO), nano-iron sulfide (nano-FeS), and rGO/nano-FeS were separately hybridized with biocathodes to systematically investigate the effects of different hybridized biocathodes on the performance of MFCs for Cr(VI)-containing wastewater treatment. The results showed that the FeS group exhibited the best Cr(VI) removal capability, with a maximum removal kinetic constant of 0.184 h⁻¹, which was 3.60 times that of the Control group, and showed the smallest performance decline after three consecutive cycles. Mechanistic analysis indicated that nano-FeS promoted the transformation of Cr(VI) into Cr(III) and Cr(0) through its strong adsorption and reducing capacities; it also enhanced biofilm cell activity and the protein/polysaccharide ratio in extracellular polymeric substances; furthermore, it shaped a multi-taxon-dominated microbial community capable of Cr(VI) tolerance and reduction and enhanced the associated metabolic functions, thereby improving resistance to Cr(VI) stress and effectively alleviating cathode passivation. In contrast, rGO tended to enhance biocathode conductivity and electricity generation in MFCs, with the rGO + FeS group achieving the highest power density output of 51.54 ± 3.62 mW/m², which was 1.22 times that of the Control group, as well as the smallest decline in power density after three consecutive cycles. Overall, nanomaterial hybridization reshaped interfacial electron transfer and microbial stress resistance in biocathodes, enabling efficient Cr(VI) removal and stable electricity generation, and providing a new strategy to construct long-term stable bioelectrochemical systems for heavy metal-containing wastewater treatment. Full article

Fe-cat and Ti-cat catalytic additives synthesized from converter slags of Qarmet JSC using acid activation followed by ex situ sulfidation were studied. By full-profile X-ray analysis, it was found that Fe-cat is mainly a sulphide system (FeS troilite + keilite, 52.8 wt% in total), while Ti-cat is mainly oxide (Mg(Ti₂O₅), 70.8 wt%). In model experiments for the hydrogenation of a mixture of phenanthrene and benzothiophene in the presence of polyethylene as a hydrogen donor, the catalytic additive Ti-cat provides preferential hydrogenation of aromatic structures (conversion of phenanthrene 47.2%), while Fe-cat is characterized by complete conversion of benzothiophene and high yield of cleavage products. During hydroconversion of the heavy fraction of primary coal tar, the yield of liquid products was 64.0% by weight, mainly in the form of a middle distillate fraction of 200–300 °C. The hydrogen balance showed that molecular hydrogen was in excess; an increase in the hydrogen content in liquid products (from 8.0 to 9.64 wt%) indicates the transfer of hydrogen from donors to the liquid phase. The optimum content of polyethylene is 1.0–1.5 wt%, providing maximum enrichment of liquid products with hydrogen (H/C = 1.53). Full article

Cu(I)-doped Sb₂S₃ powders were synthesized using the hot-injection method, with the aim of reducing crystalline particle size and tailoring their morphology to make them more spherical and better suited for spray deposition as an absorber layer in photovoltaic devices. Structural and microstructural analyses confirmed the successful formation of elongated (rod-like) crystalline Sb₂S₃ particles. CuSbS₂, itself a semiconducting material with a high light-absorption coefficient, formed in large amounts in Cu-doped systems, in the form of agglomerates of platelet-like particles. The third abundant phase was an amorphous phase present as spherical nanoparticles composed of uniformly distributed Sb, Cu and S. The presence of Cu decreased Sb₂S₃ particle size but did not significantly influence its morphology. Chlorides in the synthesis solution enabled faster crystallization than when acetates are the only present anionic species. When Cu, Sb and S sources were added during hot injection in stoichiometric amounts to form CuSbS₂, this phase was not reached, and Cu₉S₅ and Cu₁₂Sb₄S₁₃ were the dominant phases, indicating Cu-rich phases have a higher tendency to crystallize in specific conditions with an excess of antimony, and, potentially, sulfur is needed to obtain pure CuSbS₂. Full article

Determining the oxygen barrier packaging material is crucial for maintaining the quality and freshness of chilled chicken during low-temperature storage. Chilled chicken was packaged in three materials with different oxygen permeability: medium-oxygen-barrier packaging (MORP, 23.95 cm³/(m²·24 h·0.1 MPa)), low-oxygen-barrier packaging (LORP, 1631.44 cm³/(m²·24 h·0.1 MPa)), and polyethylene packaging (OPP, 10,600.00 cm³/(m²·24 h·0.1 MPa)). The packaged samples were then stored at 4 °C for 9 d. Compared to the OPP group, where Pseudomonas, Acinetobacter, and Lactobacillus dominated, MORP and LORP significantly inhibited Pseudomonas growth, resulting in slower microbial population growth during storage. Owing to the distinct composition of dominant spoilage bacteria, the LORP group demonstrated significantly lower levels of sulfide and nitrogen oxides during storage compared to other groups. Within the first 7 days, the LORP group exhibited markedly lower TVB-N levels in comparison to both the MORP and OPP groups. During the late storage stage, the muscle fiber structure in both the MORP and LORP groups remained relatively intact. In summary, packaging materials with low to medium barrier properties are more effective in maintaining chicken freshness and extending its shelf life to up to 9 days. This method potentially provides an effective foundation for maintaining the quality of poultry meat. Full article

Thermomagnetic-fraction geochemistry has shown promise beneath transported cover, but area-scale applications rarely combine explicit element-association analysis, statistical robustness tests and transparent target prioritization. We evaluate this workflow in the largely covered Jing’erquan Ni-Cu metallogenic area using 985 soil samples collected over approximately 140 km² at an average spacing of about 300 m (7.0 samples km⁻²). After removal of pre-existing strongly magnetic grains, 100 g aliquots were heated under oxygen-limited conditions at 650 °C for 45 min, and the newly generated magnetic fraction was separated at an instrument-current setting of 1 A. Twelve indicators were analyzed using descriptive statistics, correlation analysis, hierarchical clustering, principal component analysis (PCA), spatial clustering and a three-term composite score. Four rotated factors explain 75.1% of the variance; Cr and Ni load at 0.95 on F2, while TFe₂O₃, Zn, Co and Cu covary on F1. Pearson–Spearman matrix agreement (r = 0.990), winsorized-versus-original Pearson agreement (r = 0.999), and PCA factor-congruence coefficients (>0.998) show that the principal associations are not controlled by the largest Cu, Ni or Cr values. Alternative composite weights retain all eight named follow-up targets, although internal ranking changes when Cu is emphasized. Among them, JQ-1–JQ-4 are assigned high follow-up priority by the expert-informed score. The coincidence of JQ-1 with the known Jing’erquan Ni-Cu mining area provides an internal plausibility check for the workflow, whereas JQ-2–JQ-8 remain unverified follow-up targets. These results show that the thermomagnetic-fraction dataset delineates multielement surface geochemical anomalies in covered terrain and can serve as a complementary screening tool for subsequent Ni-Cu exploration. Full article

Process mineralogy provides valuable information for understanding the mineralogical and textural characteristics of volcanogenic massive sulfide (VMS) deposits and their influence on mineral liberation. This study investigates the relationship between ore texture and chalcopyrite liberation in massive and stockwork/disseminated copper ore samples from a Kuroko-type VMS deposit in the Eastern Black Sea Region of Türkiye. Whole-rock mineralogy, textures, and mineral intergrowth relationships were characterized using X-ray diffraction (XRD), reflected-light ore microscopy, and field-emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (FE-SEM/EDS) mapping. Both ore types contain chalcopyrite, pyrite, sphalerite, and galena as the main valuable minerals, with quartz as the predominant gangue mineral. However, they show distinct textural characteristics. In the massive ore, chalcopyrite occurs as fine-grained aggregates filling fractures in cataclastic pyrite and commonly forms complex intergrowths with adjacent sulfides. In contrast, the stockwork/disseminated ore exhibits a more dispersed sulfide distribution within a quartz-rich matrix. Liberation analyses conducted across six particle size fractions, ranging from −600 + 500 to −38 µm, demonstrate that chalcopyrite liberation increases as particle size decreases. The stockwork/disseminated ore consistently exhibits higher liberation than the massive ore across all size fractions. The highest liberation values were achieved in the −38 µm fraction, reaching 98% for the stockwork/disseminated ore and 90% for the massive ore. FE-SEM/EDS mapping confirms that micron-scale sulfide intergrowths in the massive ore limit complete liberation and contribute to its lower liberation efficiency. These findings highlight the influence of ore texture on chalcopyrite liberation and provide useful geometallurgical information for optimizing the grinding and beneficiation of Kuroko-type VMS ores. Full article

Silver (Ag)-based conductive coatings are widely used in electrical contacts due to their excellent electrical conductivity, low contact resistance, good thermal stability and oxidation resistance, although their susceptibility to sulfidation and environmental corrosion is a concern under certain service conditions. In recent years, significant progress has been achieved in both the manufacture and performance optimization of Ag-based coatings to satisfy the demanding requirements of modern electrical and electronic systems. This review summarizes recent advances in fabrication techniques and processing parameters for Ag-based coatings, including electroplating, electroless deposition, magnetron sputtering, electrospark deposition, thermal spraying, and electrical explosion spraying on metallic substrates, particularly on copper and steel substrates. More attention is given to microstructural design strategies, such as the incorporation and homogeneous dispersion of reinforcement or solid lubricant phases within the Ag matrix, to enhance contact reliability and operational endurance. The performance of Ag-based coatings is analyzed in terms of their physical, chemical and mechanical properties, electrical contact resistance, friction and wear behavior, arc erosion resistance, and environmental durability under different service conditions. Key challenges, including coating degradation under high electrical loads, mechanical wear, and corrosive environments, are highlighted. Future research directions are outlined, focusing on multifunctional coating structures that enhance surface performance and ensure the long-term durability of electrical contacts. Full article

Objectives: The aim of this study was to determine whether direct evidence shows that contemporary guideline-directed heart failure (HF) pharmacotherapies influence cardiac remodeling through hydrogen sulfide (H₂S) signaling, and to define the resulting evidence gap. Design: A systematic review was conducted according to PRISMA 2020. Registration: PROSPERO CRD420251238589. Data Sources: MEDLINE (PubMed), Web of Science, Scopus, and the Cochrane Library; searches were initiated in March 2025, covered publications from January 2007 onward, and were last updated in November 2025. Eligibility Criteria: Primary studies had to include (A) an HF or cardiac-remodeling model, (B) an HF-relevant pharmacological intervention, (C) direct assessment or manipulation of H₂S biology, and (D) at least one cardiac-remodeling endpoint. Results: Of the 40,796 unique records screened, 50 reports underwent full-text assessment and 14 unique studies were included. No study demonstrated that the remodeling benefits of ACE inhibitors, ARBs, ARNIs, beta-blockers, MRAs, hydralazine/isosorbide dinitrate, or SGLT2 inhibitors are mediated by endogenous H₂S signaling. Doiron et al. evaluated empagliflozin with or without the H₂S donor SG1002 in experimental HFpEF; the combination improved several outcomes beyond empagliflozin alone, but this adjunctive design does not establish H₂S mediation of empagliflozin action. Most eligible evidence concerned exogenous H₂S donors in animal models and reported improvements in fibrosis, hypertrophy, oxidative stress, mitochondrial injury, and cardiac function. The overall certainty was low because of preclinical predominance, heterogeneous models and H₂S assays, donor-specific pharmacology, and incompletely reported randomization and blinding. Conclusions: The principal finding is negative but clinically important: direct evidence that H₂S mediates established HF pharmacotherapy is currently absent. H₂S remains a promising experimental therapeutic candidate rather than an established shared mechanism or clinically validated treatment target. Full article

Mineral-scale deposition remains a persistent flow-assurance and asset-integrity constraint in oil and gas production. Calcium carbonate, calcium sulfate, barium sulfate, iron sulfide, and mixed inorganic scale deposits reduce tubing internal diameter. They also impair near-wellbore permeability, block safety-critical valves, reduce heat-transfer efficiency, and intensify under-deposit corrosion. Conventional management relies on prediction, chemical inhibition, squeeze treatments, acid dissolution, chelation, mechanical scraping, milling, jetting, and operational water management. These methods are indispensable, but each has a restricted operating envelope. Key limitations include mineral selectivity, corrosion risk, environmental discharge, intervention cost, debris generation, and poor effectiveness against chemically resistant sulfate scales, particularly BaSO₄. Ultrasound has therefore attracted interest as a non-chemical technology. Acoustic cavitation, microstreaming, pressure oscillation, mechanical vibration, and micro jetting may suppress nucleation, disturb boundary layers, weaken adhesion, and fragment brittle deposits. This review critically evaluates ultrasound-assisted scale prevention and removal, with emphasis on production tubing and oilfield relevance. Existing studies show credible mechanistic plausibility and promising laboratory performance for CaCO₃, CaSO₄/gypsum, KCl, NaCl, and membrane or heat-transfer fouling systems. It also compares performance metrics, field cases, and technology-readiness barriers. The evidence is less mature for long steel tubulars operating under high-pressure, high-temperature, multiphase production conditions. Current evidence positions ultrasound at technology-readiness level (TRL) 3–4 for CaCO₃ and CaSO₄ systems, where laboratory and bench-scale validation is established, and at TRL 2–3 for BaSO₄, where mechanistic plausibility exists but controlled experimental validation remains absent. The technology is not yet at the pilot–production transition for downhole tubing applications, but it is approaching that threshold for surface process equipment. Its most credible near-term role is as an intensifier paired with low-dose chemical inhibitors, where acoustic boundary-layer disruption can reduce the minimum inhibitory concentration threshold of inhibitors, and with mild chelating agents for early-stage BaSO₄ management, where ultrasound-enhanced mass transfer may accelerate chelant penetration into deposit microstructure. Advancing ultrasound from its current TRL toward field qualification requires targeted BaSO₄ scale validation in steel tubing systems, acoustic field mapping under HPHT multiphase conditions, mass-removal metrics, and a structured pilot programme. Full article