Search Results (3,805)

The rapid translocation of pesticide and metal residues in the environment and their entry into the food chain pose a significant risk to human health. Given the high global consumption of honey, quality control emphasizes the need for continuous monitoring and risk assessment. To evaluate contamination levels in honey from northern Croatia, a region with intensive agricultural land use, 38 comb honey and 22 extracted honey samples were collected by purposive one-time sampling in June 2023. These samples were analyzed for 190 pesticides using liquid chromatography–tandem mass spectrometry (LC-MS/MS) and gas chromatography–tandem mass spectrometry (GC-MS/MS), and for 17 trace metal(loid)s using inductively coupled plasma mass spectrometry (ICP-MS). The highest detection frequencies were observed for fipronil-sulfone, trifloxystrobin, and coumaphos in comb honey, and for N-(2,4-dimethylphenyl)-formamide (DMF) and N-(2,4-dimethylphenyl)-N′-methylformamidine (DPMF) in extracted honey. Glyphosate was the only pesticide to exceed the European Union (EU) maximum residue level (MRL) of 0.05 mg/kg in three honey samples. Elemental analysis quantified most target metals, with aluminum (Al), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni) and zinc (Zn) being the most abundant, while silver (Ag), arsenic (As), and selenium (Se) were not detected in this study. None of the samples contained lead (Pb) above the regulatory limit for honey established in the EU (0.1 mg/kg). To ensure food safety, further efforts are required to assess the health risks associated with exposure to these contaminants through consumption of the evaluated food. Full article

Chlorine (Cl) and sulfur (S) are two crucial mineralizing agents in silicate melts, and are closely related to the genesis of metallic mineral deposits. Magmatic ore deposits usually form in mafic–ultramafic silicate melts by the separation (liquation) of a cooling, sulfur-rich magma into two immiscible liquids. It is not easy to identify the complexation between gold (Au), cooper (Cu) and Cl, S using the current experiment methods, and the coordination of Au and Cu with Cl and S is still unclear in mafic–ultramafic silicate melts. In this study, by using first-principles molecular dynamics technique, we investigated the structure of Au, Cu, Cl and S in the (a) anhydrous and (b) hydrous peridotite melt to reveal their coordination geochemistry. Our results show that Si⁴⁺–Cl⁻, Cu⁺–O²⁻, Au⁺–O²⁻, Cu⁺–Cl⁻, Au⁺–Cl⁻, Au⁺–S²⁻, and Cu⁺–S²⁻ cannot form stable ion pairs in silicate melts; therefore, Au⁺ and Cu⁺ cannot form stable complexes with S²⁻, O²⁻ or Cl⁻ in the melts. But the diffusion coefficients of Au⁺, Cu⁺, S²⁻ and Cl⁻, their RDF values and the bonding time ratio of the silicate melt systems show that, although they cannot form stable complexes, within the range of effective chemical bond lengths, they have a high probability of approaching and interacting with each other, which enables them to form crystal embryos or liquid-phase molecules during magma evolution. Full article

The Pschorr reaction is a radical-mediated intramolecular cyclization involving diazonium salts, affording five-, six- and seven-membered fused polycyclic and heterocyclic rings, discovered by R. Pschorr in the late nineteenth century. Over the years, this classic reaction has played an important role in ring-forming reactions. In 2009 we reviewed the progress in the field. The intervening years have witnessed major advances in the application of Pschorr reaction that are mediated by various metals, by photocatalysis, and by ionic liquids, leading to the development of new and improved methods for the synthesis of diverse bioactive heterocycles. The notable progress in the field since our 2009 review provided the impetus to summarize, discuss, and put these advances in perspective. Full article

Coal gasification slag (CGS) is rich in Si-Al-Ca components and thus has potential for ceramic utilization, but associated heavy metals may pose environmental risks. In this study, CGS from Yili (Xinjiang, China) was used as the major raw material (80 wt%), with clay and waste glass as additives, to prepare ceramsite by firing green pellets (8–12 mm) at 1000–1200 °C. The phase evolution, microstructure, and heavy-metal migration were characterized, and the leaching safety was evaluated. Increasing temperature leads to progressive quartz consumption, enrichment of feldspar-type crystalline phases, and liquid-phase sintering, which together enhance densification. The apparent density and single-particle compressive strength exhibit an “increase-then-decrease” trend with temperature and reach maxima at 1150 °C, where the compressive strength is 15.38 MPa. Heavy-metal behavior is element-specific: As and Zn show stronger volatilization, whereas Mn, Ba, Ni, and Cu are largely retained in the solid phase; Cr shows intermediate, temperature-dependent volatilization. After firing at ≥1150 °C, the leached concentrations of Cr, Mn, Ni, Cu, Zn, As, and Ba under the sulfuric acid–nitric acid test (HJ/T 299-2007) are below the Class III limits of the Chinese Groundwater Quality Standard (GB/T 14848-2017). Considering phase/structure evolution, mechanical performance, and short-term heavy-metal leaching, 1150 °C is identified as the preferred firing temperature in this work. Full article

Copper anodic slime is often smelted with lead to improve silver and gold recovery, generating a fine lead-rich fly ash that contains notable amounts of selenium and tellurium. Due to its high lead content and sub-micron particle size, this residue poses significant environmental and occupational health risks. This study evaluates sodium carbonate (Na₂CO₃) leaching as an environmentally benign pre-treatment aimed at partially removing selenium and tellurium while stabilizing lead through carbonate formation. The goal is detoxification rather than maximum metal recovery, enabling safer disposal or subsequent recycling. A central composite design (CCD) in Design-Expert software (Version 12) was used to assess the effects of Na₂CO₃ concentration, temperature, solid-to-liquid ratio, and time on selenium and tellurium dissolution. Selenium recovery reached up to 53.9%, while tellurium recovery peaked at approximately 33.9%. Scanning electron microscopy showed the dust to consist mainly of semi-spherical and elongated particles, with lead carbonate forming preferentially on particle surfaces during leaching. Energy-dispersive spectroscopy confirmed conversion of lead sulfate phases to lead carbonate, which increasingly restricted selenium and tellurium dissolution. Kinetic evaluation suggested selenium leaching follows mixed control involving both surface reaction and diffusion through product layers, whereas tellurium dissolution lacked consistent kinetic behavior. Thermodynamic calculations supported the stabilization of lead as cerussite (PbCO₃), indicating improved environmental safety. The overall dissolution trends were successfully represented using an apparent Shrinking Core Model (SCM) based on measurements collected at 20 °C, 60 °C, and 100 °C. Full article

Methanol is the simplest C1 oxygenated compound possessing the highest hydrogen-to-carbon ratio and can therefore be used as an effective hydrogen carrier. Furthermore, it can be easily transported by land and sea because it is liquid at room temperature and atmospheric pressure. Methanol can be converted into hydrogen via methanol steam reforming (MSR), aqueous-phase reforming of methanol (APRM), or aqueous methanol dehydrogenation (AMDH). In this review, various catalysts for MSR, APRM, and AMDH are summarized. Highly active and stable catalysts that can operate under low steam-to-methanol ratios are needed to increase the economics of the MSR process. Compared with the MSR process, the APRM process is rather simple because the water–gas shift reaction can occur simultaneously; however, more constraints exist in the selection of active metals and supports to ensure high activity and stability under APRM conditions. The inherently low reaction rate compared to MSR and the structural vulnerability of the catalyst under severe hydrothermal conditions are obstacles that the APRM catalysts must overcome. The low intrinsic catalytic activity and the high cost of homogeneous catalysts represent fundamental limitations inherent to AMDH catalysts. Based on a literature survey of MSR, APRM, and AMDH catalysts, some future research directions are also discussed. Full article

Ice adhesion on exposed structures remains a major operational challenge, motivating the search for passive, material-based anti-icing strategies. Molecular dynamics offers a controlled way to investigate ice–surface interactions beyond the limits of experimental setups. In this work, we develop a simulation framework to model the impact of solid hexagonal ice droplets on metallic substrates. Ice impacts are simulated across a range of velocities (10–120 m/s), temperatures (120–250 K), and face-centred cubic surface materials (gold, copper, silver, aluminum, and nickel). Using LAMMPS, mW water force-field, EAM/Alloy metal potentials, and Lennard-Jones water–surface interactions, we quantify phase evolution through angular order parameter and quasi-liquid layer measurements, complemented by the CHILL+ algorithm in OVITO. By isolating all external factors, we show that melting increases with velocity and temperature and correlates with substrate properties: metals with high thermal diffusivity and low Young’s modulus tend to decrease post-collision ice melting. The ratio of the former to the latter, a derived index of merit Υ, significantly correlates with melting percentage and identifies silver as the most effective anti-ice material examined. Statistical analyses strongly suggest that these surface properties influence interfacial melting, supporting the use of this modelling framework for screening and designing anti-icing materials. Full article

Gallium-based liquid metals have garnered significant attention due to their distinct combination of metallic and liquid behavior at room temperature. This review systematically examines the fundamental properties and advanced multifunctional applications of this class of materials. Key characteristics such as low melting point, excellent fluidity, high electrical and thermal conductivity, and biocompatibility are first highlighted. Subsequently, progress in four major application areas is discussed. In sensing, these materials enable the fabrication of highly compliant and responsive devices capable of monitoring strain, temperature, and electromagnetic fields. Within biomedical engineering, their inherent low toxicity and biocompatibility underpin advances in biosensing platforms, precision drug delivery, and engineered tissue scaffolds. For energy-related applications, they are utilized in batteries and high-efficiency thermoelectric systems for converting heat into electricity. In catalysis, their dynamic and tunable interfaces facilitate efficient carbon dioxide conversion and selective thermocatalytic reactions. This review summarizes current advances in the application of gallium-based liquid metals and provides critical perspectives on future developments and opportunities in this technology. Full article

Ga-based liquid metals (GLMs) have been considered as promising thermal and electrical interface materials for advanced power electronics, combining high thermal conductivity (some types even >30 W/m·K) with fluidity at room temperature. This review systematically evaluates the dual roles of GLMs in power electronics packaging. Their function in thermal management as both thermal interface materials and active cooling media is first examined, followed by an analysis of their capabilities in forming electrical interconnections via low-temperature bonding in fluidic and solid states. However, reliable integration remains challenging due to interfacial reactions and instability with metal substrates. We discuss interfacial mechanisms with Cu and common metallizations, along with emerging regulation strategies such as surface coatings and process acceleration techniques. By examining these interfacial interactions, this work aims to guide the selection and design of surface modification strategies to either promote or inhibit reactions as needed, supporting the development of robust power electronic packaging. Full article

This study presents a combined process of sulfide precipitation followed by hydrogen peroxide leaching for rhenium recovery from copper smelting waste acid under ambient temperature and pressure. The process first removed copper through selective sulfide precipitation, then achieved co-precipitation of rhenium and arsenic to obtain a rhenium-rich precipitate. Subsequently, exploration of rhenium-containing precipitate leaching using H₂O₂ solution was conducted under isothermal conditions at 20 °C. The effects of H₂O₂ concentration, liquid-to-solid ratio, acidity, and leaching time rhenium extraction efficiency were examined systematically. The optimal leaching conditions were determined as: H₂O₂ concentration of 150 g/L, liquid-to-solid ratio of 5:1 mL/g, stirring speed of 350 r/min, and leaching time of 30 min. Under these conditions, the leaching conversions of rhenium and arsenic reached 96.0% and 93.8%, respectively. Through characterization of precipitate and leaching residue using ICP, SEM-EDS, XRD, and XPS analyses, the process and related reactions were elucidated. Results demonstrated that low-valence rhenium oxides and sulfides serve as the main reactive species during H₂O₂ leaching, whereas organic sulfur, high-valence oxides, and copper sulfide remained stable and resistant to leaching. Selective precipitation of copper effectively eliminated insoluble metal sulfides from rhenium-containing precipitates, thereby enabling efficient separation of rhenium under mild conditions. Full article

Lightweight high-entropy alloys are primarily designed to overcome the strength-to-density ratio limitations of conventional counterparts and often consist of elements with drastically different melting temperature and vapor pressure. Their chemistry, therefore, imposes challenges on alloy synthesis, particularly through liquid metal engineering routes, since elements with high vapor pressure (e.g., Mg, Zn, Li) vaporize before the higher-melting-point ingredients (e.g., Cu, V, Ni) are fully molten, resulting in volatile element loss. To overcome this challenge, a novel pressure-assisted induction melting (PAIM) process was developed and the proprietary furnace for its implementation was designed and built. The system allows precision melting of up to 10 cm³ of an alloy at temperatures up to 1700 °C while addressing the partial pressure requirements during the melting progress. The chamber is prepared using rough vacuum and re-filled with inert gas such as argon with the operating pressure range from about 10⁻⁴ MPa up to maximum of 1.6 MPa (233 psi). The alloy chemical composition can be modified in situ by feeding solid additives at specific melting stages through the isolated airlock without disrupting the pressure conditions within the chamber. The viability of the concept was verified by synthesis of two lightweight non-equimolar high-entropy alloys: Mg-rich Mg₅₀(MnAlZnCu)₅₀ and Al-rich Al₃₅Mg₃₀Si₁₃Zn₁₀Y₇Ca₅. The experiments showed that sequential multi-step melting procedures, designed based on inputs from FactSage computational analysis, when combined with PAIM synthesis, allowed manufacturing fully dense and chemically homogenous complex alloy compositions with optimal volumes for materials discovery research. Full article

Ostericum palustre (Besser) Besser (synonym Angelica pancicii Vandas ex. Velen.) is a Eurasian species from the Apiaceae family, previously related to the Balkan endemic species A. pancicii. The study aims to provide a thorough profiling of methanol-aqueous extracts from O. palustre leaves, roots, and inflorescences integrated with an evaluation of antioxidant potential and enzyme inhibitory activity towards some therapeutic targets. For the first time, a series of simple coumarins and furanocoumarins alongside phenolic and acylquinic acids, and flavonoids were annotated/dereplicated in the O. palustre of Bulgarian origin by liquid chromatography coupled with quadrupole—Orbitrap high resolution mass spectrometry acquisition platform. According to the discriminant analysis (sPLS-DA) of the biological potential, radical scavenging activity (47.9 mg TE/g in DPPH and 61.8 mg TE/g in ABTS), reducing power (102.2 mg TE/g in CUPRAC and 57.4 mg TE/g in FRAP), and metal-chelating capacity (20.1 mg EDTAE/g) accounted mainly for the stronger antioxidant activity of inflorescences extract than roots and leaves. Root extracts exhibited anti-collagenase, anti-elastase, and anti-hyaluronidase effects with lower IC₅₀ values (IC₅₀ 37.22, 42.47 and 32.09 μg/mL, respectively). Pearson relationship analysis revealed potent antioxidants including furanocoumarins (oxypeucedanin hydrate, xanthotoxol/bergaptol, byakangelicin/isobyakangelicin, ostruthol) and phenolic acids, while a series of angelols alongside feruloylquinic and dicaffeoylquinic acids, and flavonol glycosides hold significance for the neuroprotective activity of the leaves extract. The enzyme inhibitory activity of the root extracts towards collagenase, elastase and hyaluronidase, related to the anti-aging activity, was ascribed to simple hydroxylated/methoxylated coumarins. The study suggests the potential health benefits of O. palustre extracts as antioxidant, anti-aging, and neuroprotective agents. Full article

Pure LaFeO₃@C and LaCoO₃@C and substituted LaFe_1-xCo_xO₃ and LaCo_1-xFe_xO₃ perovskites (x = 0.10; 0.30) were used as catalysts for the liquid-phase oxidation of furfural at 150 °C and 30 bar of O₂ pressure. The perovskites were characterized by XRD, H₂-TPR, N₂ physisorption, TPR-MeOH, and XPS. The carbon in situ incorporation (@C) increases the surface area, favoring oxygen mobility leading to LaFeO₃@C stabilizing the redox pair Fe³⁺/Fe²⁺. In contrast, no evidence of the formation of a LaCoO₃@C perovskite structure through @C incorporation was observed. The gradual substitution of Fe with Co (10 and 30%) in LaFeO₃@C decreases the crystallinity, redox and basic properties, and surface area. For LaCoO₃@C, after the substitution of Co with 10 and 30% of Fe, only metal (La, Fe, Co) oxides as segregated phases were observed. The highest catalytic activity and selectivity to maleic acid of LaFeO₃@C is attributed to the higher surface area, crystalline structure, and surface-reducible Fe³⁺ species, favoring oxygen mobility and promoting their more oxidizing capacity. The lower catalytic activity of LaCoO₃@C, the Co- and Fe-substituted LaFeO₃@C and LaCoO₃@C catalysts, is attributed to the smaller surface area, and the similar selectivity towards maleic acid, 5-hydroxy-2(5H) and furanone indicates that the active site type is not modified in comparison to LaFeO₃@C. Full article

Non-invasive magnetic resonance imaging (MRI), as an extension of nuclear magnetic resonance (NMR) technology, enables detailed characterization of lithium-ion batteries (LIBs) in model systems. This review summarizes the fundamental principles of MRI and its applications in liquid/solid electrolytes, electrodes, and limited commercial diagnostics. Key capabilities include quantifying ion diffusion coefficients and mobility numbers in electrolytes, visualizing dendrite growth in lithium metal, and tracking lithium distribution in porous electrodes such as graphite and LiCoO₂. However, spatial and temporal resolution (typically 10–100 μm with acquisition times ranging from minutes to hours) and metal-induced shielding effects severely limit direct imaging in complete commercial batteries. Indirect methods like magnetic field imaging (MFI) show potential for defect detection. Future work should focus on sequence optimization and multimodal fusion, while emphasizing MRI’s primary role in fundamental research rather than conventional industrial testing. Full article

High-iron red mud presents a major obstacle to comprehensive resource utilization, as iron and aluminum minerals form tightly interwoven and encapsulated structures that resist conventional separation, hindering efficient co-recovery of these valuable elements. This study aimed to address this bottleneck by developing an effective strategy for iron–aluminum separation and synergistic recovery. A reduction smelting process was conducted in a sealed electric furnace using internally carbon-containing red mud pellets, enabling phase reconstruction to regulate aluminum-bearing phases while achieving iron–aluminum separation. XRD and SEM analysis verified that iron oxides were reduced to metallic iron with recovery exceeding 98%, and aluminum-bearing phases were selectively converted into active α-Al₂O₃ and mainly dodecacalcium hepta-aluminate (Ca₁₂Al₁₄O₃₃) in the slag. Under optimized Bayer leaching conditions (150 g/L NaOH, 240 °C, 90 min, liquid-to-solid ratio 6:1), aluminum extraction exceeded 60%, comparable to conventional red mud processing. This work overcomes the technical barrier of iron–aluminum co-recovery from high-iron red mud, offering a practical and efficient route for its sustainable valorization. Full article