Search Results (506)

The Kalasayi tungsten deposit is a medium-sized quartz-vein scheelite tungsten deposit in the Western Tianshan, Central Asia Orogenic Belt. The Kalatawu pluton yielded Late Carboniferous zircon U–Pb ages (313.99–310.32 Ma), and molybdenite Re–Os dating gives an isochron age of 302.3 ± 1.8 Ma for W mineralization, indicating an ~8–12 Myr magmatic-hydrothermal system. Whole-rock geochemistry classifies the pluton as aluminous A₂-type granite formed in a post-collisional extensional setting. Zircon Hf isotopes (εHf(t) = +2.8 to +8.3) suggest a mixed juvenile lower crust source with mantle input. In situ LA-ICP-MS scheelite trace element analysis and REE geochemistry distinguish two populations: proximal Group I (high Mo, low Sr, low ΣREE, right-inclined REE patterns) is precipitated from oxidizing magmatic fluid, and distal Group II (low Mo, high Sr, high ΣREE, flat REE patterns, strong positive Eu anomalies) records reduced, mixed fluid with intense fluid–rock interaction. Fluid inclusion data show decreasing temperature and salinity proximally to distally, confirming that mixing of magmatic and meteoric water led to cooling and pH increase that caused W precipitation. A four-stage metallogenic model is proposed for a post-collisional extensional setting, providing robust evidence for A-type granite-related, multi-stage W mineralization and establishing exploration indicators for the southwestern Central Asia Orogenic Belt. Full article

Carbonic anhydrases (CAs) are a class of zinc-containing metalloenzymes widely present in the biological world, catalyzing the reversible hydration of CO₂ to form HCO₃⁻ and H⁺. These enzymes play essential roles in pH homeostasis, gas exchange, metabolic regulation, and virulence expression in pathogens. In fungi, CAs mainly belong to the α- and β-classes and have undergone extensive diversification during evolution. In plant pathogenic fungi, the functions of CAs have extended beyond traditional metabolic roles, evolving into key “environmental adaptation and virulence regulatory factors.” This review takes Magnaporthe oryzae as a model organism and integrates recent advances in CA research across various microorganisms. It systematically summarizes the classification diversity, structural features, subcellular localization, and biological functions of fungal CAs. Particular emphasis is placed on the molecular profile, mitochondrial localization, physical interaction network, and multiple functional roles of the MoCA family members in conidial development, appressorium formation, oxidative stress response, HCO₃⁻ homeostasis, nitrogen metabolism, and mitochondrial energy metabolism. Based on these findings, this study proposes a multi-layered analytical framework integrating CA molecular characteristics, mitochondrial functional regulation, and fungal pathogenicity. It explores the potential of targeting fungal CAs for the development of novel selective fungicides and highlights key research directions, aiming to provide theoretical insights into plant-fungal interactions and innovative strategies for disease control. Full article

Re-establishing native plant communities is critical for restoring post-mine influenced sites. A major challenge is that mining activity can result in poor soil quality that is not conducive to plant growth. Various soil amendments can provide organic material and nutrients that assist plant growth. Biosolids, treated solids recovered from municipal wastewater, can be used as a soil amendment to improve soil quality of mine-influenced landscapes and provide the nutrients for plant growth. The objectives of this study were (1) to determine an appropriate rate of biosolid application to promote the colonization of native plants and (2) to determine the effects of the biosolids on soil properties. In 2021, a field study was devised that tested four biosolid application rates (0, 125, 250, and 375 dry Mg/ha). The site was located in a mining area in the southern interior of British Columbia, Canada, with six replicates per experimental combination. This study demonstrated that biosolids significantly increased the productivity and diversity of the plant community. Biosolids reduced soil pH and increased soil organic matter, carbon and nitrogen concentrations. Receiving soils were either similar to or marginally high in arsenic (As) and molybdenum (Mo). In contrast, biosolids tended to significantly increase Cu levels compared to the control soils. Higher rates of biosolids did not lead to significantly higher plant productivity or diversity than the lower rates. The results of this study suggest that biosolids may significantly help restore sustainable grassland ecosystems in post-mining environments even at a lower application rate of 125 dry Mg/ha. Full article

This work investigates the photo-Fenton degradation of azo dyes in an aqueous medium rich in sodium dodecyl sulfate (SDS), using methyl orange (MO) as a model contaminant. Chemometric modeling was integrated with mechanistic analysis to elucidate the role of the micellar pseudophase in radical distribution, dye partitioning, and overall reaction efficiency. A sequential experimental design strategy was applied, combining fractional factorial design and response surface methodology (RSM) to evaluate the individual and interactive effects of key operational variables and determine the optimal operating conditions for maximum degradation efficiency. Under optimized conditions (pH 2.85, [H₂O₂] = 100 mM, [Fe²⁺] = 0.5 mM, [SDS] = 13 mM, [MO] = 0.01 mM), MO degradation reached 98.4% in 5 min. Spectroscopic and partitioning studies revealed a strong affinity of MO for the micellar interface, indicating preferential localization in a microheterogeneous environment. Radical scavenging experiments confirmed that hydroxyl radicals are the dominant oxidizing species in water, while the reduction observed in the presence of SDS suggested secondary radical pathways derived from the surfactant under micellar conditions. Kinetic analyses highlighted the role of intermolecular interactions and micellar compartmentalization in radical generation. The optimized system was successfully extended to other azo dyes, underscoring the potential of surfactant-rich organized media to enhance photo-Fenton reactions in complex aqueous environments. Full article

Water quality in high-elevation agricultural river valleys is shaped by regional environmental gradients and localized hydrogeochemical conditions, but multi-year assessments often do not clearly separate routine hydrochemical variability from metal(loid) risk. This study evaluates a public multi-year dataset from the agricultural concentration area of the Yarlung Zangbo River and its two tributaries on the Qinghai–Tibet Plateau. The dataset includes 444 river-water, groundwater, and irrigation-water samples collected in 2019, 2020, 2021, 2023, and 2024. We combined water-type-specific standard assessment, normalized exceedance frequencies, spatial visualization, and descriptive correlation analysis with terrain, land-cover, soil, and climate-hydrological predictors. Because sampling coverage and hydrological-period classification differed among years, annual contrasts were interpreted descriptively rather than as fixed-site temporal trends. Most samples were neutral to weakly alkaline, whereas electrical conductivity (EC), total dissolved solids (TDS), and salinity varied more strongly across years and sampling locations. In total, 70 samples exceeded at least one evaluated criterion, but only 12 samples were flagged in the metal(loid) assessment. Eight samples exceeded the 0.05 mg/L As screening threshold, occurring only in 2023 and 2024 (3.25% and 2.92% of samples in those years, respectively), and were concentrated in a localized reach rather than distributed basin-wide. As was positively associated with Mo and Hg, whereas relationships with Fe, Mn, pH, EC, TDS, and salinity were weak or inconsistent; dissolved oxygen was not available for the high-As samples. These results distinguish broad dissolved-solute variability from localized As-dominated risk and show that the dataset supports regional screening and monitoring prioritization, but not definitive redox, speciation, or source-apportionment conclusions. Full article

Industrial wastewater containing synthetic dyes is difficult to treat because many dyes are chemically stable, highly colored, and resistant to natural degradation. In this study, a Ag₂CO₃/montmorillonite (Ag₂CO₃/MMT) composite photocatalyst was synthesized by an in situ precipitation method using acid-activated MMT as a low-cost clay support. The prepared material was characterized by XRD, FTIR, SEM, BET, and UV–Vis diffuse reflectance spectroscopy to evaluate its structural, morphological, textural, and optical properties. XRD and FTIR confirmed the formation of crystalline Ag₂CO₃ on the MMT support, while SEM analysis showed dispersed Ag₂CO₃ surface particles/deposits on the clay sheets. BET analysis indicated that the composite retained mesoporosity after Ag₂CO₃ deposition, which is beneficial for dye adsorption and diffusion. The photocatalytic performance was evaluated using methylene blue (MB) and methyl orange (MO) under visible-light irradiation. The Ag₂CO₃/MMT composite showed efficient dye decolorization, with faster degradation of cationic MB than anionic MO, mainly due to stronger electrostatic interaction between MB and the negatively charged catalyst surface. Kinetic analysis followed a pseudo-first-order model, with apparent rate constants of 0.036 min⁻¹ for MB and 0.021 min⁻¹ for MO. Operational parameters, including solution pH, irradiation time, and catalyst dosage, strongly influenced photocatalytic efficiency. Reactive species trapping experiments indicated that superoxide radicals (•O₂⁻) and photogenerated holes (h⁺) were the dominant oxidative species. The catalyst retained more than 91% activity after four cycles, indicating good recyclability under the tested conditions. These results suggest that Ag₂CO₃/MMT is a promising visible-light-responsive photocatalyst for dye-contaminated wastewater treatment. Full article

An adsorptive stripping voltammetric method for the determination of ultra trace amounts of Mo(VI) using an electrode based on a mixture of carbon nanotubes and spherical glassy carbon (CNT/SGC) was developed. The electrode was modified by depositing a lead film in situ during each measurement cycle. In a supporting electrolyte containing 0.2 mol/L of acetic buffer pH = 5.3; 0.2 mmol/L of Pb(II); and 0.15 mmol/L of cupferron, the stripping response observed at −0.62 V was proportional to the Mo(VI) concentration within the range of 7 nmol/L to 0.6 µmol/L. The measurement protocol involved a 20 s electrode modification followed by a 30 s adsorption of Mo(VI)–cupferron complexes. The limit of detection was found to be 2.5 nmol/L with a correlation coefficient of 0.997. The method has been applied to the determination of Mo(VI) in mineral water samples. Full article

The corrosion resistance of metallic materials is closely related to their service environment. In ammonia-based desulfurization post-treatment systems, 316L stainless steel, 2507 duplex stainless steel, and TA2 commercially pure titanium are widely used as candidate materials for key components such as desulfurization heat exchangers. In this study, the pitting corrosion behavior of 316L, 2507, and TA2 was investigated in simulated ammonia desulfurization post-treatment solutions with different pH. The results show that increasing solution acidity leads to a decrease in the capacitive arc radius and polarization resistance, while the donor concentration and pitting susceptibility of the three materials increase. Under the same pH condition, TA2 exhibits the highest stability and corrosion resistance, followed by 2507, whereas 316L shows the poorest corrosion resistance. The composition of the TA2 passivation film (TiO₂) does not change as the pH of the simulated solution is modified. With increasing solution acidity, the relative XPS peak-area fraction of TiO₂ in TA2 increases, indicating that TiO₂ remains the dominant component of the passive film. In contrast, the relative contents of Cr- and Mo-containing oxides/hydroxides in 316L and 2507 decrease, and MoO₃ is replaced by MoO₂ under acidic conditions. These changes suggest weakened passive-film stability and reduced protection of the substrate. Full article

Photocatalytic degradation of organic pollutants has emerged as a promising approach for wastewater treatment due to its environmental friendliness and high efficiency under mild conditions. This study focuses on evaluating materials for the decolorization of methylene blue (MB) and methyl orange (MO), which are commonly used cationic and anionic dyes, respectively, known for their persistence and toxicity in aquatic environments. The research investigates the synthesis of a Mott–Schottky junction at the interface of two materials using MXene as a dopant. We synthesized three MXene-containing Porous Organic Polymers (POP-2MX, POP-6MX, and POP-10MX), incorporating 2%, 6%, and 10% MXene, respectively. UV–Vis spectroscopy tests revealed that all polymers exhibited high degradation efficiency; however, POP-6MX demonstrated the best overall activity. Under illumination of a 500 W Xenon lamp (λ > 420 nm) with a catalyst loading of 1 mg/mL, POP-6MX achieved complete adsorption-corrected degradation of MB and MO within 10 and 45 min, respectively. This research also investigated the influence of pH on photocatalytic performance under homogeneous aqueous conditions, revealing that neutral pH provides the optimal environment for degradation activity. The photocatalytic mechanism follows a reactive oxygen species (ROS)-dominated pathway, primarily driven by superoxide radicals (•O₂⁻) and hydroxyl radicals generated through photochemical reactions. These results demonstrate the potential of POP-1/MXene composites as efficient and recyclable photocatalysts for sustainable dye wastewater treatment applications. Full article

Graphene-reinforced CrCoNiFeMo high-entropy alloy composite coatings were fabricated on 17-4PH stainless steel by laser cladding for the surface protection of industrial robotic end-effector grippers. The effects of graphene content on microstructure, hardness, wear behavior and corrosion resistance were investigated. Graphene-derived carbon suppressed Laves and σ phases and promoted the in situ formation of M23C6, M7C3 and Co2C carbides, transforming the coating into a carbide-reinforced FCC/BCC composite structure. The average hardness increased from 462 HV0.2 to 676 HV0.2 with increasing graphene content. The 0.4 wt.% graphene coating showed the best wear resistance, with the lowest friction coefficient of 0.42 and minimum wear scar width and depth of 546 μm and 5.72 μm, which was attributed to carbide strengthening and the possible formation of a carbonaceous lubricating tribo-layer. The 0.2 wt.% graphene coating exhibited the best corrosion resistance, with the lowest corrosion current density of 5.81 μA/cm² and the highest impedance response. Excessive graphene caused carbon-rich agglomeration, excessive carbide precipitation and weakened passivation. This work provides a feasible surface strengthening strategy for 17-4PH stainless steel robotic gripper components. Full article

Heavy metal (HM) contamination in urban soils is a pressing global issue, particularly in rapidly industrializing regions like Kazakhstan, where anthropogenic activities such as transportation, energy production, and manufacturing exacerbate accumulation in ecosystems. In Almaty, the largest city in Kazakhstan, urban expansion and legacy pollution pose risks to soil functions, biodiversity, and public health through bioaccumulation and migration pathways. This study evaluates the spatial distribution and ecological impacts of total heavy metal concentrations (HMs) (Pb, Cd, As, Zn, Cu, Ni, Co, Mo, Mn) in Almaty’s soils to inform remediation strategies. Soil samples (n = 73) were collected using a systematic grid sampling method across urban, industrial, and peri-urban zones in Almaty. HM concentrations were determined via X-ray fluorescence spectrometry (XRF) following GOST 33850-2016 standards. Pollution indices (contamination factor K_c and integrated pollution index Z_c) were calculated relative to Kazakhstani permissible limits (PDK RK) and Russian approximate permissible concentrations (ODK RF). Statistical analyses included Spearman’s correlation, boxplots, and coefficient of variation. Morphological, physicochemical (pH, humus content), and biological assessments evaluated degradation. Spatial interpolation via GIS mapped the hotspots. HM distributions showed significant variability, with As, Zn, and Ni exceeding norms in >90% of samples (median K_c ≈ 5 for As). Z_c classified >70% of sites as hazardous or extremely hazardous (Z_c > 32), with hotspots in central-eastern districts (Z_c 90–145). Strong correlations (ρ ≥ 0.6) identified a technogenic group (Pb–Zn–Cu–Ni) from traffic and industry, contrasting predominantly geogenic elements with possible anthropogenic contribution (As–Co–Mo–Mn). Pollution induced soil compaction, reduced humus/pH, and disrupting biogeochemical cycles. Local exceedances were noted near TECs, factories, and transport hubs. Almaty’s soils exhibit pervasive technogenic HM pollution, driven by urban sources, leading to ecosystem degradation and health risks. Future research should incorporate vertical profiling and isotopic sourcing for refined risk models. Prioritized monitoring and phytoremediation in hotspots are recommended to enhance resilience, aligning with UN SDGs for sustainable cities and ecosystems. Future research should incorporate vertical profiling and isotopic sourcing for refined risk models. Full article

Cubane-type iron–sulfur clusters play central roles in biological nitrogen fixation, where precise redox regulation governs multi-electron transfer processes. However, how heterometal centers and terminal ligands cooperatively modulate the electronic structure and redox behavior of such clusters remains insufficiently understood. Herein, we report a systematic study on a series of cubane-type [MoFe₃S₃N] clusters as structural mimics of nitrogenase cofactors. Using [(Tp*)MoFe₃S₃(μ₃-NSiMe₃)Cl₃]⁻ as a common precursor, thiolate (RS⁻; R = Me, Et, Ph) and N-heterocyclic carbene (NHC^R; R = Me, Et, iPr) ligands were introduced to probe ligand effects under an invariant cluster framework. All complexes were fully characterized by single-crystal X-ray diffraction and electrochemical measurements. Combined with previously reported tungsten analogues, a direct comparison reveals that both heterometal identity (Mo vs. W) and terminal ligand environment significantly influence local electron density and intermetallic redox cooperativity. Notably, strong σ-donating NHC ligands and heavier heterometal centers induce distinct modulation patterns, highlighting their synergistic roles. This work provides a unified platform for disentangling metal- and ligand-driven effects and offers feasible strategies for the rational tuning of redox properties in heterometallic Fe–S clusters. Full article

The Nuri deposit is currently the only Cu-W-Mo deposit in the Gangdese metallogenic belt, Tibet, China, that contains large-scale tonnages for both Cu and WO₃ resources, accompanied by a medium-scale Mo resources. Previous studies have suggested the potential presence of concealed porphyry-type orebodies at depth, yet effective exploration tools for verifying this hypothesis remain lacking. In this study, microscopic identification, electron probe microanalysis (EPMA), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were integrated to investigate the mineral chemical characteristics of chlorite from the Nuri deposit. The aim was to evaluate the effectiveness of chlorite geochemistry as an exploration vector for predicting deep concealed porphyry orebodies and to establish corresponding exploration indicators. Chlorite in the deposit can be genetically classified into metasomatic (Chl-I) and hydrothermal (Chl-II) types. Both types are Mg-rich varieties, indicating formation under conditions of low oxygen fugacity and low pH. With decreasing vertical distance to the orebody and toward the southeast direction of the exploration section, the contents of Ti (10–950 ppm) and V (50–820 ppm), as well as the Ti/Sr, Ti/Mn, Ti/Li, and V/Li ratios, progressively increase. In contrast, the concentrations of Li (36–390 ppm), Mn (1270–6730 ppm), Sr (1–510 ppm), and Zn (110–1100 ppm) systematically decrease. These systematic compositional variations demonstrate that chlorite geochemistry is an effective exploration tool in the Nuri mining area and suggest the presence of a concealed mineralization center or porphyry orebody beneath the interval from ZK4501 to ZK4502. Full article

Green synthesis of KGM-capped CeO₂ nanoparticles was successfully achieved through a simple coprecipitation method using Konjac Glucomannan (KGM) as a biopolymeric capping and stabilizing agent. The reaction conditions were optimized by varying pH (9–11) and temperature (30–70 °C) to evaluate their influence on nanoparticle formation and photocatalytic performance. The synthesized KGM–CeO₂ nanoparticles were comprehensively characterized using FTIR, UV–Vis spectroscopy, XRD, SEM–EDS, TEM, DLS, and ZP analysis to investigate their structural, optical, morphological, and surface properties. The characterization results confirmed the successful formation of porous sponge-like branched CeO₂ nanostructures with irregular morphology. XRD analysis revealed the crystalline nature of the nanoparticles with an average crystallite size of approximately 7.7 nm, while DLS analysis showed an average hydrodynamic particle size of 29.7 nm with a biomodal particle size distribution. The positive zeta potential value (+16.75 mV) confirmed good colloidal stability and reduced agglomeration due to effective capping by KGM. The synthesized nanoparticles also exhibited favorable optical properties with band gap values suitable for photocatalytic applications. The adsorption and photocatalytic degradation performance of the KGM–CeO₂ nanoparticles was investigated against synthetic textile dyes, including Naphthol Blue Black (NBB), Methyl Orange (MO), and a mixed NBB–MO dye system under acidic conditions. Using an adsorbent dosage of 50 mg and dye concentrations of 100 mg/L, the material achieved degradation efficiencies of approximately 99% for NBB, 91% for MO, and 52% for the mixed dye system under UV irradiation for 120 min. Adsorption kinetic studies indicated that the pseudo-second-order model provided the best fit, suggesting that chemisorption is the dominant adsorption mechanism involving multifunctional surface interactions. These findings are particularly relevant for industrial wastewater treatment, since actual textile effluents typically contain complex mixtures of dyes and organic contaminants rather than single dye pollutants. The mixed dye experiments, therefore, provide a more realistic simulation of industrial wastewater conditions. Overall, the synthesized KGM–CeO₂ nanoparticles demonstrate excellent potential as an eco-friendly, cost-effective, and sustainable multifunctional material for adsorption-assisted photocatalytic treatment of dye-contaminated wastewater. Further optimization of operational conditions and catalyst surface properties may enhance its efficiency in multicomponent wastewater systems. Full article

This study investigates the electronic and photocatalytic properties of greenly fabricated rutile-phase titanium dioxide (bTiO₂) modified with iron vanadate (Fe/bTiO₂/VO₄) and vanadium-substituted goethite (Fe/bTiO₂/VOOH) by detailed experimental assay and density functional theory (DFT) calculations. Our analysis of the density of states (DOS), band structure, and work function reveals that both dopant systems significantly modify the electronic structure of pure rutile bTiO₂. The dye methyl orange (MO) was used as the model pollutant. During photodegradation tests, parameters such as the reaction time, solid-to-liquid ratio, initial concentrations of the photocatalyst and dye, as well as distance of the lamp from the reactor and pH were varied. Degradation kinetics follows the equation of the pseudo-first order law for both photocatalysts (k_VO4 = 0.058 min⁻¹ and k_VOOH = 0.065 min⁻¹), while degradation efficiencies of 92% and 99% were observed after 120 min at pH 3, respectively. Specifically, the DOS analysis highlights the contribution of Fe 3d and V 3d orbitals, which create new electronic states within the bandgap, facilitating charge transfer. These insights provide a strong foundation for the rational design of novel, highly efficient Fe/bTiO₂-based photocatalysts for the degradation of organic pollutants in water. Full article