Search Results (345)

After the European Union’s ban of zinc pyrithione from cosmetic use, piroctone olamine, climbazole, and salicylic acid have become the most common anti-dandruff active ingredients used in cosmetics today. Other conventional chemistries and less frequently used active ingredients, like hexamidine diisethionate and selenium sulfide, have also seen a recent upward trend. Entirely new technologies, like propanediol caprylate and propanediol undecylenate, are only in their initial stages but are ready to change the industry. The aim of the following study is to holistically characterize these compounds, regarding their chemical data, mode of action, and study results, where available, to shed light on the pros and cons and to take a detailed look at environmental considerations, market situation and regulatory aspects. In addition, many commercially available anti-dandruff consumer products combine multiple active ingredients to address the multifaceted nature of the condition, often targeting both fungal activity and scalp inflammation. Full article

Zinc oxide (ZnO) and zinc sulfide (ZnS) nanocomposites represent promising multifunctional photocatalysts due to their complementary band structures and synergistic charge separation. ZnO–ZnS nanocomposites with varied ZnS content were synthesized to elucidate the composition–structure–property relationships governing their multifunctional performance. Structural characterization using XRD, SEM/EDS, Raman spectroscopy, and XPS confirmed the coexistence of wurtzite crystalline phases of ZnO and ZnS. SEM analysis revealed ZnS fine deposition on the ZnO surface. XPS measurements showed a gradual increase in the amount of ZnS on the ZnO surface with increasing sulfide content and a shift in the valence band maximum from 2.32 eV (pure ZnO) to 0.77 eV (pure ZnS). Optical measurements (IR, UV–Vis diffuse reflectance, photoluminescence) demonstrated that, despite the evolution of vibrational and luminescence features characteristic of ZnS, the apparent band gap remained nearly constant at 3.16–3.18 eV across the series. Photocatalytic methylene blue (MB) degradation followed pseudo-first-order kinetics, peaking for ZN_2 (1% ZnS, k_app = 103 × 10⁻³ min⁻¹), which is 1.7 times higher than for pure ZnO. This enhanced performance is consistent with an S-scheme-like heterojunction that facilitates electron migration to the ZnS conduction band while retaining ZnO valence band holes for oxidation. Scavenging experiments confirmed that electrons dominate MB degradation (k_app up to 185.1 × 10⁻³ min⁻¹ with EDTA/t-BuOH/Ar), outperforming hole-mediated pathways. Antibacterial assays against Staphylococcus aureus revealed good antimicrobial activity for all nanoparticles. The nanocomposite’s antibacterial activity was similar across all samples and was only slightly lower than that of pure ZnS and ZnO. Full article

With the advancement of wind power technology towards larger-capacity and higher-power turbines, their main shaft bearings face significant lubrication challenges under extreme temperatures. In this study, seven modified greases were prepared by adding 0.5 wt.% of tungsten disulfide (WS₂), zinc sulfide (ZnS), and sulfurized isobutylene (T321). The concentration of all additives is given in weight percent (wt.%). Using a combined approach of friction and wear testing along with rheological analysis, this study systematically evaluated the tribological performance of the greases at high temperature (80 °C)—with the friction coefficient and wear scar diameter as key parameters—and their rheological properties across a wide temperature range (−20 °C to 80 °C), focusing primarily on shear stress and viscosity. All critical input parameters, including temperature, load, and shear rate, were precisely controlled and monitored using calibrated instruments. Results indicate that the WS₂ and T321 compounding system demonstrated optimal performance, achieving a low average coefficient of friction of 0.024 and an average wear scar diameter of only 0.367 mm. At the same time, the WS₂/T321 composite formulation exhibits excellent shear stability at high temperatures and good flow properties at low temperatures, demonstrating optimal viscosity–temperature characteristics. This study develops a promising grease formulation through multidimensional performance evaluation, offering key experimental support for designing high-performance wind turbine spindle bearing greases under high-temperature conditions. Full article

Mafic mine tailings are highly resistant to bioleaching due to their silicate-rich composition, low sulfide content, and strong buffering capacity. This study aimed to assess the potential use of heterotrophic bioleaching to promote the release of metals from mafic tailings by evaluating the organic acid production and leaching capabilities of indigenous bacterial isolates and a known lactic acid producer, Lactiplantibacillus plantarum ATCC 8014. Indigenous acid-producing heterotrophic bacteria were isolated from a vanadium-titanium-bearing magnetite tailings in Québec, Canada, and screened for organic acid production in various culture media. The most active bacteria were L. plantarum and two isolates identified by their 16S rRNA gene as Enterococcus (CBGM-1C) and Acetobacter (BL-F) sp. They produced significant quantities of lactic acids, followed by acetic, citric, and gluconic acids during glucose metabolism, through fermentative or oxidative pathways. A two-step bioleaching process was implemented, consisting of an initial organic acid production phase followed by tailings leaching at 5% pulp density over 10 days at 30 °C. Metal solubilization and mineralogical analyses demonstrated strain-dependent and metal-specific mobilization, with zinc being the only element efficiently leached (up to ~74% recovery by L. plantarum). XRD analyses confirmed partial dissolution and reduced crystallinity of key silicate phases without secondary mineral formation. These findings indicate that heterotrophic leaching can selectively mobilize more labile metals such as Zn from alkaline, silicate-rich tailings, although its overall efficiency for refractory elements remains limited under the tested conditions. Full article

The Lanuoma sediment-hosted lead–zinc (Pb–Zn) deposit, situated in the central part of the Sanjiang base metal metallogenic belt (SMB) within the Changdu Basin, is hosted by Triassic Bolila Formation limestone. The source of metals and sulfur (S), as well as the ore-forming processes for the deposits in this belt, are contentious. To constrain the metal and sulfur sources and to define the ore-forming mechanism, we analyzed Zn, Pb, and S isotopes of sphalerite and robinsonite, as well as Zn isotopes of the host limestone and the metamorphic basement. Sphalerite shows homogeneous δ⁶⁶Zn values (−0.31‰ to −0.12‰; mean = −0.20‰). The calculated δ⁶⁶Zn of the ore-forming fluid (~0.00‰) matches that of the Triassic limestone, indicating a sedimentary Zn source (δ⁶⁶Zn = −0.11‰ to −0.09‰; average 0.00‰). Robinsonite displays a wider δ⁶⁶Zn range (−0.22‰ to 0.44‰), reflecting a mixture of sedimentary and metamorphic sources (δ⁶⁶Zn = 0.12‰ to 0.42‰; average 0.22‰). Lead isotopes of sphalerite are uniform (²⁰⁶Pb/²⁰⁴Pb = 19.041–19.079) and indicative of a sedimentary rock source, whereas robinsonite shows wide variation (²⁰⁶Pb/²⁰⁴Pb = 19.070–19.156) and linear trends between low- and high-radiogenic end-members, indicating mixed Pb sources from sedimentary rocks and metamorphic basement. Sulfur isotopic compositions of sulfides (δ³⁴S = −1.4‰ to 2.6‰; mean = −0.1‰) cluster near 0‰, consistent with a deep magmatic origin. A strong linear correlation between ²⁰⁶Pb/²⁰⁴Pb and δ⁶⁶Zn, coupled with a lack of correlation between both ²⁰⁶Pb/²⁰⁴Pb and δ³⁴S and δ⁶⁶Zn and δ³⁴S in the sulfides, indicates that Pb and Zn were derived from a common metal source, whereas sulfur originated from a distinct reservoir. Combined with previously published fluid inclusion, rare earth element, and multi-isotopic constraints, these results suggest that Pb–Zn mineralization at Lanuoma was controlled by a mixing between metal-rich basinal brines and sulfur-rich deep-sourced fluids, leading to sulfide precipitation dominated by open-space filling. This study provides new insights into the genesis and mineralization process of sediment-hosted Pb–Zn deposits in the Sanjiang metallogenic belt. Full article

Herein, an electrochemically activated zinc–cobalt-layered double hydroxide/nickel–cobalt-sulfide (EA ZnCo-LDH/NCS) hierarchical composite electrode was fabricated in situ via coupled hydrothermal synthesis and electrodeposition. The influence of electrolyte concentration on the activation efficiency was systematically analyzed, and the corresponding effects of electrochemical activation on each component were elucidated. Benefiting from the introduction of the Zn component and subsequent electrochemical activation, the composite electrode exhibits a marked performance enhancement. The EA ZnCo-LDH/NCS electrode achieves a high areal specific capacitance (Cs) of 11.39 F cm⁻² at 4 mA cm⁻², maintains 70.15% of this value when the current density is increased ten-fold, and retains 80.05% of its initial capacity after 5000 cycles. Full article

Metal oxide nanomaterials have emerged as transformative materials in the quest to enhance the energy density and overall performance of lithium-ion batteries (LIBs) and solid-state batteries (SSBs). Their unique properties—including their large surface areas and short ion diffusion pathways—make them ideal for next-generation energy storage technologies. In LIBs, the high surface-to-volume ratio of metal oxide nanomaterials significantly enlarges the active interfacial area and shortens the lithium-ion diffusion paths, leading to an improved high-rate performance and enhanced energy density. Transition metal oxides (TMOs) such as nickel oxide (NiO), copper oxide (CuO), and zinc oxide (ZnO) have demonstrated significant theoretical capacities, while binary systems like NiCuO offer further improvements in cycling stability and energy output. Additionally, layered lithium-based TMOs, particularly those incorporating nickel, cobalt, and manganese, have shown remarkable promise in achieving high specific capacities and long-term stability. The synergistic integration of metal oxides with carbon-based nanostructures, such as carbon nanotubes (CNTs), enhances the electrical conductivity and structural durability further, leading to a superior electrochemical performance in LIBs. In SSBs, the use of oxide-based solid electrolytes like garnet-type Li₇La₃Zr₂O₁₂ (LLZO) and sulfide-based electrolytes has facilitated the development of high-energy-density systems with excellent ionic conductivity and chemical stability. However, challenges such as high interfacial resistance at the electrode–electrolyte interface persist. Strategies like the application of lithium niobate (LiNbO₃) coatings have been employed to enhance interfacial stability and maintain electrochemical integrity. Furthermore, two-dimensional (2D) metal oxide nanomaterials, owing to their high active surface areas and rapid ion transport, have demonstrated considerable potential to boost the performance of SSBs. Despite these advancements, several challenges remain. Morphological optimization of nanomaterials, improved interface engineering to reduce the interfacial resistance, and solutions to address dendrite formation and mechanical degradation are critical to achieving the full potential of these materials. Full article

Resistance to conventional antibiotics remains a global health challenge. The search for more effective antimicrobial agents has led to the consideration of nanoparticles due to their potential biocidal activities. This study synthesized, characterized, and evaluated the antimicrobial behavior of cadmium sulfide nanoparticles (CdS NPs) during incubations at 37 °C and at room temperature (rt; 23 to 27 °C). XRD results showed that the synthesized nanoparticles had a cubic zinc blende structure, while microscopic investigations confirmed the particle size to be 7.236 nm on average. UV-Vis spectroscopy showed that the nanoparticles are active in the visible light region. Raman spectroscopy results showed peaks at 302.3 cm⁻¹ and 601 cm⁻¹, which represent the first- and second-order longitudinal optical phonon. Agar well diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays were conducted to investigate the antimicrobial activity of CdS NPs (50 mg/mL, 25 mg/mL, and 10 mg/mL) against Escherichia coli and Staphylococcus aureus. CdS NPs were effective against both test organisms. However, they were more effective against Gram-negative E. coli. The higher the concentration of CdS NPs, the more effective they were against the test organisms. Furthermore, MBC results showed greater bactericidal activity of CdS NPs at 37 °C. With increasing incidences of antimicrobial resistance against conventional antimicrobial agents, especially in wastewater treatment, nanoparticles are considered promising alternatives and the next generation of antimicrobial agents. Full article

This study investigates the atmospheric corrosion behavior of zinc in tropical marine environments affected by hydrogen sulfide (H₂S), particularly from the decomposition of stranded Sargassum algae. Four exposure sites in Martinique with varying levels of H₂S and marine chlorides were selected. Gravimetric analysis showed that zinc thickness loss reached up to 45 µm after one year at the most impacted site (Frégate Est), compared to only 3–10 µm at less contaminated locations. This degradation level classifies the site as “extremely corrosive” according to ISO 9223. Electrochemical impedance spectroscopy (EIS) and linear polarization measurements revealed distinct corrosion behaviors. After 12 months of exposure, the polarization resistance and corrosion current density reached R_p = 916 Ω·cm² and I_corr = 28 µA·cm² at the Frégate Est site and R_p = 1835 Ω·cm² and I_corr = 6 µA·cm² at the Vauclin site. In H₂S-poor environments (Diamant, Vert-Pré, Vauclin), corrosion resistance increased over time due to the formation of protective layers such as hydrozincite and simonkolleite. In contrast, H₂S-rich environments favored the formation of sulfur-based compounds like elemental sulfur and zinc sulfide (ZnS), which exhibit poor protective properties and result in lower polarization resistance and higher corrosion current densities. Polarization curves confirmed a general decrease in anodic and cathodic currents over time, with less significant improvements in passivation at H₂S-impacted sites. The corrosion mechanism is influenced by both pollutant type and exposure duration. Overall, this study highlights the synergistic effect of H₂S and chlorides on accelerating zinc corrosion and underscores the need for adapted protection strategies in tropical coastal zones affected by Sargassum proliferation. Full article

Metal–organic frameworks (MOFs) have emerged as versatile precursors and templates for developing high-performance electrode materials for aqueous zinc-ion batteries (ZIBs), owing to their adjustable porosity, abundant metal-coordination sites, and structural flexibility. Among the diverse array of MOFs investigated, those based on manganese, copper, and cobalt, as well as their derivatives, have shown exceptional potential, exhibiting enhanced redox activity, structural integrity, and advantageous zinc-ion storage kinetics compared with many other MOF systems. This study emphasizes the synthesis methodologies, structural characteristics, and electrochemical benefits of these three significant MOF families. After a succinct overview of MOF chemistry, synthesis methodologies, and fundamental design principles for ZIB electrode materials, the article presents a systematic, comparative evaluation of Mn-MOFs, Cu-MOFs, Co-MOFs and V-MOFs, along with their corresponding metal oxides, sulfides, phosphates, carbon composites, and multidimensional hybrid structures. Recent publications for each MOF type are detailed in separate tables, including synthesis methods, morphological development, electrochemical behavior, and performance metrics. The discourse highlights the distinct properties of each metal center, Mn’s multivalent redox chemistry, Cu’s superior electron transport and coordination adaptability, and Co’s elevated activity and stable structures, which together facilitate improved ion diffusion, substantial reversible capacity, and prolonged cycling durability. Ultimately, existing obstacles and potential research avenues are delineated to advance MOF-based materials for next-generation aqueous ZIB systems. Full article

The Qingshan lead–zinc (Pb–Zn) deposit in northwestern Guizhou Province is a structurally controlled, carbonate-hosted system formed from basin-derived hydrothermal processes. Geology, fluid inclusion, and isotopic data reveal a multi-stage hydrothermal circulation after Emeishan Large Igneous Province (ELIP, ~260 Ma) tectono-thermal reactivation within the Sichuan–Yunnan–Guizhu triangle (SYGT) area. Fluid inclusion microthermometry indicates that ore-forming fluids were derived from deep sources influenced by enhanced crustal heat flow linked with possible thermal input from Indo-Caledonian tectonic activity after ELIP. Ore-stage calcite records mixed carbon derived from marine carbonates with additional inputs from organic matter and deep-sourced fluids, reflecting carbonate dissolution and fluid–rock interaction. Sulfide, together with fluid inclusion temperatures > 120 °C, indicates sulfur derived from evaporitic sulfate reduced by thermochemical sulfate reduction (TSR); the heavy sulfur signature and partial isotopic disequilibrium among coexisting sulfides reflect dynamic fluid mixing during ore deposition. Lead isotopes indicate metallogenic metals were leached mainly from Devonian–Permian carbonates with subordinate basement input. Ore precipitated by cooling, depressurization, and mixing of metal-rich, H₂S-bearing fluids in structurally confined zones where the carbonate–clastic interface effectively trapped ore-forming fluids, producing high-grade sphalerite–galena mineralization. Collectively, these data support a Huize-type (HZT) carbonate-hosted Pb–Zn genetic model for the Qingshan deposit. Full article

Thin-film organic solar cells (TFOSCs) are gaining momentum as next-generation photovoltaic technologies due to their lightweight nature, mechanical flexibility, and low cost-effective fabrication. In this pioneering study, we report for the first time the incorporation of cobalt-doped zinc sulfide $(\mathrm{Z}\mathrm{n}\mathrm{S}/\mathrm{C}\mathrm{o})$ nanoparticles (NPs) into a poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) bulk-heterojunction photoactive layer. $\mathrm{Z}\mathrm{n}\mathrm{S}/\mathrm{C}\mathrm{o}$ NPs were successfully synthesized via a wet chemical method and integrated at varying concentrations (1%wt, 3%wt, and 5%wt) to systematically investigate their influence on device performance. The optimal doping concentration of 3%wt yielded a remarkable power conversion efficiency (PCE) of 4.76%, representing a 102% enhancement over the pristine reference device (2.35%) under ambient laboratory conditions. The observed positive trend is attributed to the localized surface plasmon resonance (LSPR) effect and near-field optical enhancement induced by the presence of ZnS/Co NPs in the active layer, thereby increasing light-harvesting capability and exciton dissociation. Comprehensive morphological and optical characterizations using high-resolution scanning electron microscopy (HRSEM), high-resolution transmission electron microscopy (HRTEM), and spectroscopic techniques confirmed uniform nanoparticle dispersion, nanoscale crystallinity, and effective light absorption. These findings highlight the functional role of $\mathrm{Z}\mathrm{n}\mathrm{S}/\mathrm{C}\mathrm{o}$ NPs as dopants in enhancing TFOSC performance, providing valuable insights into optimizing nanoparticle concentration. This work offers a scalable and impactful strategy for advancing high-efficiency, flexible, and wearable organic photovoltaic devices. Full article

The Wunuer deposit is an important hydrothermal Zn-Pb-Ag-Mo polymetallic deposit in the central Great Xing’an Range, NE China. The zinc–lead polymetal mineralization is closely hosted by the volcanic rocks of the Manketouebo formation (rhyolite and lithic crystal tuff) and related to the Mesozoic granite porphyry. Field evidence and petrographic observations have identified three mineralization stages within this deposit from deep to shallow: (1) late magmatic stage with vein-type Mo mineralization characteristics and mainly related to the deep granite porphyry; (2) magmatic–hydrothermal transition stage characterized by breccia-type Zn mineralization, which occurred within a steep cryptoexplosive breccia; and (3) hydrothermal stage featured by vein-type Zn-Pb-Ag mineralization hosted by the ore-bearing fractured zone. In this contribution, we present the mineralogy, zircon U-Pb age, sphalerite Rb-Sr dating, whole-rock geochemistry, and Hf-S-Pb isotopes of the Wunuer deposit. LA-ICP-MS zircon U-Pb dating of the ore-related granite porphyry, rhyolite, and lithic crystal tuff suggests that the Mo mineralization from the late magmatic stage occurred between 144.8 Ma and 145.8 Ma. The Rb-Sr isochron dating of sphalerite indicates that the hydrothermal stage Zn mineralization age is 121 ± 2.3 Ma, which is related to the volcanism of Baiyin’gaolao Formation in the Wunuer area. The concentrated and positive δ³⁴S_V-CDT values (0.17‰~5.40‰) of sulfides, as well as uniform Pb isotope compositions of granite porphyry intrusion and galena, jointly imply a magmatic source of metallogenic materials for Pb-Zn mineralization. Whole-rock geochemistry and Hf-Pb isotopes reveal that the granite porphyry and rhyolite both originated from a mantle-derived juvenile component and assimilated by minor ancient crustal material in an extensional setting. Our study demonstrates the prospect of further exploration for two mineralization events in the hydrothermal polymetallic deposits of the central Great Xing’an Range. Full article

Zinc sulfide nanomaterials (ZnS NMs) are widely used in many important technological applications, and the performance efficiency is determined by the nanostructure, size, and shape. This indicates that achieving a desirable surface architecture is pivotal for any application. One of the efficient and cost-effective techniques, the hydrothermal method, offers uniform size, specific shape, and bulk synthesis capability. This research deals with the preparation of ZnS NMs exhibiting unique surface structures such as spherical, nano-pentagon, and nano-hexagon shapes through employing different zinc precursors and surfactants. The obtained material’s crystal structure was classified as cubic sphalerite and exhibited high purity, as analyzed by XRD, SEM-EDX, TEM, and XPS. Furthermore, the synthesized ZnS NMs were tested for their shape-dependent biosensing application, such as specific antibacterial tests against routine human pathogens such as E. coli, K. pneumoniae, and S. aureus. Several antibacterial methods, such as bacterial colony plate count, growth inhibition analysis, and minimum inhibition concentration (MIC) measurements were carried out. The results confirmed that the antibacterial action in the method employed was dependent on three factors: the NM shape, concentration, and type/nature of bacteria. Especially, the prepared ZnS NMs exhibited excellent antibacterial sensing characteristics, as observed from the lower MIC values in the range of 15.6~250 µg/mL. Full article