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21 pages, 1368 KiB  
Article
Liquid-Phase Hydrogenation over a Cu/SiO2 Catalyst of 5-hydroximethylfurfural to 2,5-bis(hydroxymethyl)furan Used in Sustainable Production of Biopolymers: Kinetic Modeling
by Juan Zelin, Hernán Antonio Duarte, Alberto Julio Marchi and Camilo Ignacio Meyer
Sustain. Chem. 2025, 6(3), 22; https://doi.org/10.3390/suschem6030022 - 6 Aug 2025
Abstract
2,5-bis(hydroxymethy)lfuran (BHMF), a renewable compound with extensive industrial applications, can be obtained by selective hydrogenation of the C=O group of 5-hydroxymethylfurfural (HMF), a platform molecule derived from lignocellulosic biomass. In this work, we perform kinetic modeling of the selective liquid-phase hydrogenation of HMF [...] Read more.
2,5-bis(hydroxymethy)lfuran (BHMF), a renewable compound with extensive industrial applications, can be obtained by selective hydrogenation of the C=O group of 5-hydroxymethylfurfural (HMF), a platform molecule derived from lignocellulosic biomass. In this work, we perform kinetic modeling of the selective liquid-phase hydrogenation of HMF to BHMF over a Cu/SiO2 catalyst prepared by precipitation–deposition (PD) at a constant pH. Physicochemical characterization, using different techniques, confirms that the Cu/SiO2–PD catalyst is formed by copper metallic nanoparticles of 3–5 nm in size highly dispersed on the SiO2 surface. Before the kinetic study, the Cu/SiO2-PD catalyst was evaluated in three solvents: tetrahydrofuran (THF), 2-propanol (2-POH), and water. The pattern of catalytic activity and BHMF yield for the different solvents was THF > 2-POH > H2O. In addition, selectivity to BHF was the highest in THF. Thus, THF was chosen for further kinetic study. Several experiments were carried out by varying the initial HMF concentration (C0HMF) between 0.02 and 0.26 M and the hydrogen pressure (PH2) between 200 and 1500 kPa. In all experiments, BHMF selectivity was 97–99%. By pseudo-homogeneous modeling, an apparent reaction order with respect to HFM close to 1 was estimated for a C0HMF between 0.02 M and 0.065 M, while when higher than 0.065 M, the apparent reaction order changed to 0. The apparent reaction order with respect to H2 was nearly 0 when C0HMF = 0.13 M, while for C0HMF = 0.04 M, it was close to 1. The reaction orders estimated suggest that HMF is strongly absorbed on the catalyst surface, and thus total active site coverage is reached when the C0HMF is higher than 0.065 M. Several Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetic models were proposed, tested against experimental data, and statistically compared. The best fitting of the experimental data was obtained with an LHHW model that considered non-competitive H2 and HMF chemisorption and strong chemisorption of reactant and product molecules on copper metallic active sites. This model predicts both the catalytic performance of Cu/SiO2-PD and its deactivation during liquid-phase HMF hydrogenation. Full article
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9 pages, 1477 KiB  
Proceeding Paper
Preparation of Nanosized Mesoporous Metal Oxides
by Olena Korchuganova, Emiliia Tantsiura, Kamila Abuzarova and Alina M. Balu
Chem. Proc. 2025, 17(1), 7; https://doi.org/10.3390/chemproc2025017007 - 1 Aug 2025
Viewed by 3
Abstract
Nowadays, nanosized mesoporous oxides are of increasing interest to scientists. They can be used as components of heterogeneous catalysts, for photo- and electrocatalysis, as gas sensors, etc. For instance, the desired properties in catalysts include a nano size and homogeneity of the particles [...] Read more.
Nowadays, nanosized mesoporous oxides are of increasing interest to scientists. They can be used as components of heterogeneous catalysts, for photo- and electrocatalysis, as gas sensors, etc. For instance, the desired properties in catalysts include a nano size and homogeneity of the particles that form the catalyst. The particle sizes of oxides are set at the initial stage of their formation, as precursors of precipitation in the context of wet chemistry. The creation of optimal conditions is possible through the use of homogeneous precipitation, where the precipitant is formed within the solution itself as a result of a hydrolysis reaction. The resolution of this issue involved the utilization of urea in our experimental setup, obtaining the hydrolysis products of ammonia and carbon dioxide. Consequently, precipitation reactions can be utilized to obtain hydroxides, carbonates, or hydroxy carbonates of metals. The precursors were calcined, obtaining nanosized mesoporous oxides, which can have a wide range of applications. Nanosized 0.1–50 nm metal oxides were obtained, including those aluminum, iron, indium, zinc, nickel, and cobalt. Full article
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13 pages, 1750 KiB  
Article
Mineral-Based Synthesis of CuFe2O4 Nanoparticles via Co-Precipitation and Microwave Techniques Using Leached Copper Solutions from Mined Minerals
by Carolina Venegas Abarzúa, Mauricio J. Morel, Gabriela Sandoval-Hevia, Thangavel Kavinkumar, Natarajan Chidhambaram, Sathish Kumar Kamaraj, Nagarajan Dineshbabu and Arun Thirumurugan
Minerals 2025, 15(8), 819; https://doi.org/10.3390/min15080819 - 1 Aug 2025
Viewed by 157
Abstract
Environmental sustainability and responsible resource utilization are critical global challenges. In this work, we present a sustainable and circular-economy-based approach for synthesizing CuFe2O4 nanoparticles by directly utilizing copper oxide minerals sourced from Chilean mining operations. Copper sulfate (CuSO4) [...] Read more.
Environmental sustainability and responsible resource utilization are critical global challenges. In this work, we present a sustainable and circular-economy-based approach for synthesizing CuFe2O4 nanoparticles by directly utilizing copper oxide minerals sourced from Chilean mining operations. Copper sulfate (CuSO4) was extracted from these minerals through acid leaching and used as a precursor for nanoparticle synthesis via both chemical co-precipitation and microwave-assisted methods. The influence of different precipitating agents—NaOH, Na2CO3, and NaF—was systematically evaluated. XRD and FESEM analyses revealed that NaOH produced the most phase-pure and well-dispersed nanoparticles, while NaF resulted in secondary phase formation. The microwave-assisted method further improved particle uniformity and reduced agglomeration due to rapid and homogeneous heating. Electrochemical characterization was conducted to assess the suitability of the synthesized CuFe2O4 for supercapacitor applications. Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurements confirmed pseudocapacitive behavior, with a specific capacitance of up to 1000 F/g at 2 A/g. These findings highlight the potential of CuFe2O4 as a low-cost, high-performance electrode material for energy storage. This study underscores the feasibility of converting primary mined minerals into functional nanomaterials while promoting sustainable mineral valorization. The approach can be extended to other critical metals and mineral residues, including tailings, supporting the broader goals of a circular economy and environmental remediation. Full article
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17 pages, 6856 KiB  
Article
Selection of Optimal Parameters for Chemical Well Treatment During In Situ Leaching of Uranium Ores
by Kuanysh Togizov, Zhiger Kenzhetaev, Akerke Muzapparova, Shyngyskhan Bainiyazov, Diar Raushanbek and Yuliya Yaremkiv
Minerals 2025, 15(8), 811; https://doi.org/10.3390/min15080811 - 31 Jul 2025
Viewed by 180
Abstract
The aim of this study was to improve the efficiency of in situ uranium leaching by developing a specialized methodology for selecting rational parameters for the chemical treatment of production wells. This approach was designed to enhance the filtration properties of ores and [...] Read more.
The aim of this study was to improve the efficiency of in situ uranium leaching by developing a specialized methodology for selecting rational parameters for the chemical treatment of production wells. This approach was designed to enhance the filtration properties of ores and extend the uninterrupted operation period of wells, considering the clay content of the productive horizon, the geological characteristics of the ore-bearing layer, and the composition of precipitation-forming materials. The mineralogical characteristics of ore and precipitate samples formed during the in situ leaching of uranium under various mining and geological conditions at a uranium deposit in the Syrdarya depression were identified using an X-ray diffraction analysis. It was established that ores of the Santonian stage are relatively homogeneous and consist mainly of quartz. During well operation, the precipitates formed are predominantly gypsum, which has little impact on the filtration properties of the ore. Ores of the Maastrichtian stage are less homogeneous and mainly composed of quartz and smectite, with minor amounts of potassium feldspar and kaolinite. The leaching of these ores results in the formation of gypsum with quartz impurities, which gradually reduces the filtration properties of the ore. Ores of the Campanian stage are heterogeneous, consisting mainly of quartz with varying proportions of clay minerals and gypsum. The leaching of these ores generates a variety of precipitates that significantly reduce the filtration properties of the productive horizon. Effective compositions and concentrations of decolmatant (clog removal) solutions were selected under laboratory conditions using a specially developed methodology and a TESCAN MIRA scanning electron microscope. Based on a scanning electron microscope analysis of the samples, the effectiveness of a decolmatizing solution based on hydrochloric and hydrofluoric acids (taking into account the concentration of the acids in the solution) was established for the destruction of precipitate formation during the in situ leaching of uranium. Geological blocks were ranked by their clay content to select rational parameters of decolmatant solutions for the efficient enhancement of ore filtration properties and the prevention of precipitation formation. Pilot-scale testing of the selected decolmatant parameters under various mining and geological conditions allowed the optimal chemical treatment parameters to be determined based on the clay content and the composition of precipitates in the productive horizon. An analysis of pilot well trials using the new approach showed an increase in the uninterrupted operational period of wells by 30%–40% under average mineral acid concentrations and by 25%–45% under maximum concentrations with surfactant additives in complex geological settings. As a result, an effective methodology for ranking geological blocks based on their ore clay content and precipitate composition was developed to determine the rational parameters of decolmatant solutions, enabling a maximized filtration performance and an extended well service life. This makes it possible to reduce the operating costs of extraction, control the geotechnological parameters of uranium well mining, and improve the efficiency of the in situ leaching of uranium under complex mining and geological conditions. Additionally, the approach increases the environmental and operational safety during uranium ore leaching intensification. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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17 pages, 7751 KiB  
Article
Microanalysis-Based Simulation of Heterogeneous Dispersoid Distribution in an Al Alloy After the Homogenization Stage
by Nicolás García Arango, Roman Schuster, Rainer Abart and Erwin Povoden-Karadeniz
Crystals 2025, 15(8), 695; https://doi.org/10.3390/cryst15080695 - 30 Jul 2025
Viewed by 142
Abstract
We simulate the dispersoid distribution within the Al matrix grains of an aluminum 6082 alloy by combining finite difference cell modeling with mean-field precipitation simulations. The results demonstrate that the initial as-cast microstructure and the heating rate during the ramp-up to the isothermal [...] Read more.
We simulate the dispersoid distribution within the Al matrix grains of an aluminum 6082 alloy by combining finite difference cell modeling with mean-field precipitation simulations. The results demonstrate that the initial as-cast microstructure and the heating rate during the ramp-up to the isothermal homogenization temperature are the most important factors governing the dispersoid particle distribution. The simulation results are validated by Electron Probe Microanalysis (EPMA) and Optical Microscopy on experimental run products. The results indicate that dispersoids can only achieve uniform distribution throughout the grain when the heating rate to the homogenization temperature is sufficiently slow. Full article
(This article belongs to the Special Issue Advances in Processing, Simulation and Characterization of Alloys)
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12 pages, 3886 KiB  
Article
Effect of W Contents and Annealing Temperatures on the Microstructure and Mechanical Properties of CoFeNi Medium Entropy Alloys
by Yaqi Cui, Huan Ma, Li Yang, Yang Shao and Renguo Guan
Metals 2025, 15(8), 854; https://doi.org/10.3390/met15080854 - 30 Jul 2025
Viewed by 181
Abstract
In this work, the W element, with a larger atomic radius compared to Co, Fe, and Ni, was added to modify the microstructure and enhance the yield strength of CoFeNi medium entropy alloy (MEA). A detailed study was conducted to clarify the effects [...] Read more.
In this work, the W element, with a larger atomic radius compared to Co, Fe, and Ni, was added to modify the microstructure and enhance the yield strength of CoFeNi medium entropy alloy (MEA). A detailed study was conducted to clarify the effects of W additions and annealing temperatures on the microstructure evolution and mechanical properties of CoFeNiWx (x = 0, 0.1, and 0.3) MEAs. CoFeNiW0.1 retained a single FCC structure without the formation of precipitates in the FCC phase, indicating that W, with a larger atomic radius, can completely dissolve in CoFeNiW0.1. For CoFeNiW0.3 MEA, coarse particles with an average diameter of ~2 μm appeared after homogenizing. Nevertheless, when the alloy was annealed at 800 °C and 900 °C, fine particles formed, with the average diameters of approximately 144 nm and 225 nm, respectively. After annealing at 800 °C, the CoFeNiW0.3 with a partially recrystallized microstructure exhibited better comprehensive mechanical properties. Full article
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16 pages, 1865 KiB  
Article
pH-Controlled Yeast Protein Precipitation from Saccharomyces cerevisiae: Acid-Induced Denaturation for Improved Emulsion Stability
by Laura Riedel, Nico Leister and Ulrike S. van der Schaaf
Foods 2025, 14(15), 2643; https://doi.org/10.3390/foods14152643 - 28 Jul 2025
Viewed by 243
Abstract
In the search for alternative protein sources, single cell proteins have gained increasing attention in recent years. Among them, proteins derived from yeast represent a promising but still underexplored option. To enable their application in food product design, their techno-functional properties must be [...] Read more.
In the search for alternative protein sources, single cell proteins have gained increasing attention in recent years. Among them, proteins derived from yeast represent a promising but still underexplored option. To enable their application in food product design, their techno-functional properties must be understood. In order to investigate the impact of precipitation pH on their emulsion-stabilizing properties, yeast proteins from Saccharomyces cerevisiae were isolated via precipitation at different pH (pH 3.5 to 5) after cell disruption in the high-pressure homogenizer. Emulsions containing 5 wt% oil and ~1 wt% protein were analyzed for stability based on their droplet size distribution. Proteins precipitated at pH 3.5 stabilized the smallest oil droplets and prevented partitioning of the emulsion, outperforming proteins precipitated at higher pH values. It is hypothesized that precipitation under acidic conditions induces protein denaturation and thereby exposes hydrophobic regions that enhance adsorption at the oil–water interface and the stabilization of the dispersed oil phase. To investigate the stabilization mechanism, the molecular weight of the proteins was determined using SDS-PAGE, their solubility using Bradford assay, and their aggregation behavior using static laser scattering. Proteins precipitated at pH 3.5 possessed larger molecular weights, lower solubility, and a strong tendency to aggregate. Overall, the findings highlight the potential of yeast-derived proteins as bio-surfactants and suggest that pH-controlled precipitation can tailor their functionality in food formulations. Full article
(This article belongs to the Section Nutraceuticals, Functional Foods, and Novel Foods)
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19 pages, 1816 KiB  
Article
Rethinking Infrared and Visible Image Fusion from a Heterogeneous Content Synergistic Perception Perspective
by Minxian Shen, Gongrui Huang, Mingye Ju and Kai-Kuang Ma
Sensors 2025, 25(15), 4658; https://doi.org/10.3390/s25154658 - 27 Jul 2025
Viewed by 276
Abstract
Infrared and visible image fusion (IVIF) endeavors to amalgamate the thermal radiation characteristics from infrared images with the fine-grained texture details from visible images, aiming to produce fused outputs that are more robust and information-rich. Among the existing methodologies, those based on generative [...] Read more.
Infrared and visible image fusion (IVIF) endeavors to amalgamate the thermal radiation characteristics from infrared images with the fine-grained texture details from visible images, aiming to produce fused outputs that are more robust and information-rich. Among the existing methodologies, those based on generative adversarial networks (GANs) have demonstrated considerable promise. However, such approaches are frequently constrained by their reliance on homogeneous discriminators possessing identical architectures, a limitation that can precipitate the emergence of undesirable artifacts in the resultant fused images. To surmount this challenge, this paper introduces HCSPNet, a novel GAN-based framework. HCSPNet distinctively incorporates heterogeneous dual discriminators, meticulously engineered for the fusion of disparate source images inherent in the IVIF task. This architectural design ensures the steadfast preservation of critical information from the source inputs, even when faced with scenarios of image degradation. Specifically, the two structurally distinct discriminators within HCSPNet are augmented with adaptive salient information distillation (ASID) modules, each uniquely structured to align with the intrinsic properties of infrared and visible images. This mechanism impels the discriminators to concentrate on pivotal components during their assessment of whether the fused image has proficiently inherited significant information from the source modalities—namely, the salient thermal signatures from infrared imagery and the detailed textural content from visible imagery—thereby markedly diminishing the occurrence of unwanted artifacts. Comprehensive experimentation conducted across multiple publicly available datasets substantiates the preeminence and generalization capabilities of HCSPNet, underscoring its significant potential for practical deployment. Additionally, we also prove that our proposed heterogeneous dual discriminators can serve as a plug-and-play structure to improve the performance of existing GAN-based methods. Full article
(This article belongs to the Section Sensing and Imaging)
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19 pages, 13952 KiB  
Article
Antioxidant and Anti-Inflammatory Effects of Crude Gastrodia elata Polysaccharides in UVB-Induced Acute Skin Damage
by Jiajia Liu, Xiaoqi Yang, Xing Huang, Yuan Luo, Qilin Zhang, Feng Wang, Yicen Lin and Lianbing Lin
Antioxidants 2025, 14(7), 894; https://doi.org/10.3390/antiox14070894 - 21 Jul 2025
Viewed by 518
Abstract
Ultraviolet B (UVB) irradiation drives skin photodamage, prompting exploration of natural therapeutics. This study investigated the reparative effects and mechanisms of crude Gastrodia elata polysaccharides (GP) on UVB-induced acute skin damage. GP was extracted from fresh G. elata via water extraction and alcohol [...] Read more.
Ultraviolet B (UVB) irradiation drives skin photodamage, prompting exploration of natural therapeutics. This study investigated the reparative effects and mechanisms of crude Gastrodia elata polysaccharides (GP) on UVB-induced acute skin damage. GP was extracted from fresh G. elata via water extraction and alcohol precipitation. It is a homogeneous polysaccharide with a weight-average molecular weight of 808.863 kDa, comprising Ara, Glc, Fru, and GalA. Histopathological analysis revealed that topical application of GP on the dorsal skin of mice effectively restored normal physiological structure, suppressing epidermal hyperplasia and collagen degradation. Biochemical assays showed that GP significantly reduced the activities of MPO and MDA following UVB exposure while restoring the enzymatic activities of SOD and GSH, thereby mitigating oxidative stress. Moreover, GP treatment markedly upregulated the anti-inflammatory cytokines TGF-β and IL-10 and downregulated the pro-inflammatory mediators IL-6, IL-1β, and TNF-α, suggesting robust anti-inflammatory effects. Transcriptomics revealed dual-phase mechanisms: Early repair (day 5) involved GP-mediated suppression of hyper inflammation and accelerated necrotic tissue clearance via pathway network modulation. Late phase (day 18) featured enhanced anti-inflammatory, antioxidant, and tissue regeneration processes through energy-sufficient, low-inflammatory pathway networks. Through a synergistic response involving antioxidation, anti-inflammation, promotion of collagen synthesis, and acceleration of skin barrier repair, GP achieves comprehensive repair of UVB-induced acute skin damage. Our findings not only establish GP as a potent natural alternative to synthetic photoprotective agents but also reveal novel pathway network interactions governing polysaccharide-mediated skin regeneration. Full article
(This article belongs to the Section Natural and Synthetic Antioxidants)
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21 pages, 5914 KiB  
Article
Simple Spin-Coating Preparation of Hydrogel and Nanoparticle-Loaded Hydrogel Thin Films
by Sara Calistri, Chiara Ciantelli, Sebastiano Cataldo, Vincenzo Cuzzola, Roberta Guzzinati, Simone Busi and Alberto Ubaldini
Coatings 2025, 15(7), 859; https://doi.org/10.3390/coatings15070859 - 21 Jul 2025
Viewed by 376
Abstract
Hydrogel films receive significant attention among researchers because they combine increased stimuli responsiveness and faster responses to the already excellent properties of their component materials. However, their preparation is complex and requires that many difficulties are overcome. The present work presents a new [...] Read more.
Hydrogel films receive significant attention among researchers because they combine increased stimuli responsiveness and faster responses to the already excellent properties of their component materials. However, their preparation is complex and requires that many difficulties are overcome. The present work presents a new study regarding the preparation of pure and nanoparticle-loaded alginate-based films by spin-coating. Two-microliter solutions of sodium alginate and calcium chloride with different concentrations were deposited on a glass substrate and subjected to rapid rotations of between 100 and 1000 RPM. Film formation can be achieved by optimizing the ratio between the viscosity of the solutions, depending on their concentrations and the rotation speed. When these conditions are in the right range, a homogeneous film is obtained, showing good adherence to the substrate and uniform thickness. Films containing silver nanoparticles were prepared, exploiting the reaction between sodium borohydride and silver nitrate. The two reagents were added to the sodium alginate and calcium nitrate solution, respectively. Their concentration is the driving force for the formation of a uniform film: particles of about 50 nm that are well-dispersed throughout the film are obtained using AgNO3 at 4 mM and NaBH4 at 2 or 0.2 mM; meanwhile, at higher concentrations, one can also obtain the precipitation of inorganic crystals. Full article
(This article belongs to the Section Thin Films)
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18 pages, 6380 KiB  
Article
Synthesis and Application of Fe3O4–ZrO2 Magnetic Nanoparticles for Fluoride Adsorption from Water
by Israel Águila-Martínez, José Antonio Pérez-Tavares, Efrén González-Aguiñaga, Pablo Eduardo Cardoso-Avila, Héctor Pérez Ladrón de Guevara and Rita Patakfalvi
Inorganics 2025, 13(7), 248; https://doi.org/10.3390/inorganics13070248 - 19 Jul 2025
Viewed by 616
Abstract
This study presents the synthesis, characterization, and application of magnetic magnetite–zirconium dioxide (Fe3O4–ZrO2) nanoparticles as an efficient nanoadsorbent for fluoride removal from water. The nanoparticles were synthesized using a wet chemical co-precipitation method with Fe/Zr molar ratios [...] Read more.
This study presents the synthesis, characterization, and application of magnetic magnetite–zirconium dioxide (Fe3O4–ZrO2) nanoparticles as an efficient nanoadsorbent for fluoride removal from water. The nanoparticles were synthesized using a wet chemical co-precipitation method with Fe/Zr molar ratios of 1:1, 1:2, and 1:4, and characterized using Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). FTIR analysis confirmed the presence of Fe3O4 and ZrO2 functional groups, while XRD showed that increased Zr content led to a dominant amorphous phase. SEM and EDS analyses revealed quasi-spherical and elongated morphologies with uniform elemental distribution, maintaining the designed Fe/Zr ratios. Preliminary adsorption tests identified the Fe/Zr = 1:1 (M1) nanoadsorbent as the most effective due to its high surface homogeneity and optimal fluoride-binding characteristics. Adsorption experiments demonstrated that the material achieved a maximum fluoride adsorption capacity of 70.4 mg/g at pH 3, with the adsorption process best fitting the Temkin isotherm model (R2 = 0.987), suggesting strong adsorbate–adsorbent interactions. pH-dependent studies confirmed that adsorption efficiency decreased at higher pH values due to electrostatic repulsion and competition with hydroxyl ions. Competitive ion experiments revealed that common anions such as nitrate, chloride, and sulfate had negligible effects on fluoride adsorption, whereas bicarbonate, carbonate, and phosphate reduced removal efficiency due to their strong interactions with active adsorption sites. The Fe3O4–ZrO2 nanoadsorbent exhibited excellent magnetic properties, facilitating rapid and efficient separation using an external magnetic field, making it a promising candidate for practical water treatment applications. Full article
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17 pages, 9827 KiB  
Article
High-Temperature Mechanical and Wear Behavior of Hypoeutectic Al–Si–(Cu)–Mg Alloys with Hardening Mechanisms Dictated by Varying Cu:Mg Ratios
by Jaehui Bang, Yeontae Kim and Eunkyung Lee
Appl. Sci. 2025, 15(14), 8047; https://doi.org/10.3390/app15148047 - 19 Jul 2025
Viewed by 329
Abstract
Enhancing damage tolerance and wear resistance in Al–Si-based alloys under thermomechanical stress remains a key challenge in lightweight structural applications. This study investigates the microstructural and tribomechanical behavior of hypoeutectic Al–Si–(Cu)–Mg alloys with varying Cu:Mg ratios (3:1 vs. 1:3) under a T6 heat [...] Read more.
Enhancing damage tolerance and wear resistance in Al–Si-based alloys under thermomechanical stress remains a key challenge in lightweight structural applications. This study investigates the microstructural and tribomechanical behavior of hypoeutectic Al–Si–(Cu)–Mg alloys with varying Cu:Mg ratios (3:1 vs. 1:3) under a T6 heat treatment. Alloys A and B, with identical Si contents but differing Cu and Mg levels, were subjected to multiscale microstructural characterization and mechanical and wear testing at 25 °C, 150 °C, and 250 °C. Alloy A (Cu-rich) exhibited refined α-Al(FeMn)Si phases and homogeneously dissolved Cu in the Al matrix, promoting lattice contraction and dislocation pinning. In contrast, Alloy B (Mg-rich) retained coarse Mg2Si and residual β-AlFeSi phases, which induced local stress concentrations and thermal instability. Under tribological testing, Alloy A showed slightly higher friction coefficients (0.38–0.43) but up to 26.4% lower wear rates across all temperatures. At 250 °C, Alloy B exhibited a 25.2% increase in the wear rate, accompanied by surface degradation such as delamination and spalling due to β-AlFeSi fragmentation and matrix softening. These results confirm that the Cu:Mg ratio critically influences the dominant hardening mechanism—the solid solution vs. precipitation—and determines the high-temperature performance. Alloy A maintained up to 14.1% higher tensile strength and 22.3% higher hardness, exhibiting greater shear resistance and interfacial stability. This work provides a compositionally guided framework for designing thermally durable Al–Si-based alloys with improved wear resistance under elevated temperature conditions. Full article
(This article belongs to the Special Issue Characterization and Mechanical Properties of Alloys)
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20 pages, 18517 KiB  
Article
A Highly Sensitive Low-Temperature N-Butanol Gas Sensor Based on a Co-Doped MOF-ZnO Nanomaterial Under UV Excitation
by Yinzhong Liu, Xiaoshun Wei, Yun Guo, Lingchao Wang, Hui Guo, Qingjie Wang, Yiyu Qiao, Xiaotao Zhu, Xuechun Yang, Lingli Cheng and Zheng Jiao
Sensors 2025, 25(14), 4480; https://doi.org/10.3390/s25144480 - 18 Jul 2025
Viewed by 384
Abstract
Volatile organic compounds (VOCs) are presently posing a rather considerable threat to both human health and environmental sustainability. Among these, n-butanol is commonly identified as bringing potential hazards to environmental integrity and individual health. This study presents the creation of a highly sensitive [...] Read more.
Volatile organic compounds (VOCs) are presently posing a rather considerable threat to both human health and environmental sustainability. Among these, n-butanol is commonly identified as bringing potential hazards to environmental integrity and individual health. This study presents the creation of a highly sensitive n-butanol gas sensor utilizing cobalt-doped zinc oxide (ZnO) derived from a metal–organic framework (MOF). A series of x-Co/MOF-ZnO (x = 1, 3, 5, 7 wt%) nanomaterials with varying Co ratios were generated using the homogeneous co-precipitation method and assessed for their gas-sensing performances under a low operating temperature (191 °C) and UV excitation (220 mW/cm2). These findings demonstrated that the 5-Co/MOF-ZnO sensor presented the highest oxygen vacancy (Ov) concentration and the largest specific surface area (SSA), representing the optimal reactivity, selectivity, and durability for n-butanol detection. Regarding the sensor’s response to 100 ppm n-butanol under UV excitation, it achieved a value of 1259.06, 9.80 times greater than that of pure MOF-ZnO (128.56) and 2.07 times higher than that in darkness (608.38). Additionally, under UV illumination, the sensor achieved a rapid response time (11 s) and recovery rate (23 s). As a strategy to transform the functionality of ZnO-based sensors for n-butanol gas detection, this study also investigated potential possible redox reactions occurring during the detection process. Full article
(This article belongs to the Special Issue New Sensors Based on Inorganic Material)
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21 pages, 5158 KiB  
Article
Genesis of the Erentaolegai Silver Deposit, Inner Mongolia, Northeast China: Evidence from Fluid Inclusion and H-O-S Isotopes
by Yushan Zuo, Xintong Dong, Zhengxi Gao, Liwen Wu, Zhao Liu, Jiaqi Xu, Shanming Zhang and Wentian Mi
Minerals 2025, 15(7), 748; https://doi.org/10.3390/min15070748 - 17 Jul 2025
Viewed by 314
Abstract
The Erentaolegai silver deposit is located within the Derbugan metallogenic belt in the eastern segment of the Central Asia–Mongolia giant orogenic belt. The ore bodies are primarily hosted in the volcanic rocks of the Middle Jurassic Tamulangou Formation of the Mesozoic. The mineralization [...] Read more.
The Erentaolegai silver deposit is located within the Derbugan metallogenic belt in the eastern segment of the Central Asia–Mongolia giant orogenic belt. The ore bodies are primarily hosted in the volcanic rocks of the Middle Jurassic Tamulangou Formation of the Mesozoic. The mineralization process of the deposit is divided into three stages: Stage I: Pyrite–Quartz Stage; Stage II: Sulfide–Quartz Stage; Stage III: Quartz–Manganese Carbonate Stage. This paper discusses the ore-forming fluids, ore-forming materials, and deposit genesis of the Erentaolegai silver deposits using fluid inclusions microthermometry, laser Raman spectroscopy, and H-O-S isotope analyses. Fluid inclusion microthermometry and laser Raman spectroscopy analyses indicate that the Erentaolegai silver deposit contains exclusively fluid-rich two-phase fluid inclusions, all of which belong to the H2O-NaCl system. Homogenization temperatures of fluid inclusions in the three stages (from early to late) ranged from 257 to 311 °C, 228 to 280 °C, and 194 to 238 °C, corresponding to salinities of 1.91 to 7.86 wt%, 2.07 to 5.41 wt%, and 0.70–3.55 wt% NaCl equivalent, densities of 0.75 to 0.83 g/cm−3, 0.80 to 0.86 g/cm−3 and 0.85 to 0.89 g/cm−3. The mineralization pressure ranged from 12.2 to 29.5 MPa, and the mineralization depth was 0.41 to 0.98 km, indicating low-pressure and shallow-depth mineralization conditions. H-O isotope results indicate that the ore-forming fluid is a mixture of magmatic fluids and meteoric water, with meteoric contribution dominating in the late stage. The δ34S values of metallic sulfides ranged from −1.8 to +4.0‰, indicating that the metallogenic material of the Erentaolegai silver deposit was dominated by a deep magmatic source. This study concludes that meteoric water mixing and subsequent fluid cooling served as the primary mechanism for silver mineral precipitation. The Erentaolegai silver deposit is classified as a low-sulfidation epithermal silver deposit. Full article
(This article belongs to the Special Issue Recent Developments in Rare Metal Mineral Deposits)
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18 pages, 2162 KiB  
Article
Simultaneous Decontamination for Ammonia Nitrogen and Phosphate Efficiently by Crystal Morphology MgO-Coated Functional Biochar Derived from Sludge and Sunflower Stalk
by Zhiwei Li, Jingxin Huang, Weizhen Zhang, Hao Yu and Yin Wang
Toxics 2025, 13(7), 577; https://doi.org/10.3390/toxics13070577 - 9 Jul 2025
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Abstract
Eutrophication driven by nitrogen and phosphorus discharge remains a critical global environmental challenge. This study developed a sustainable strategy for synergistic nutrient removal and recovery by fabricating MgO-coated biochar (Mg-MBC600) through co-pyrolysis of municipal sludge and sunflower stalk (300–700 °C). Systematic investigations revealed [...] Read more.
Eutrophication driven by nitrogen and phosphorus discharge remains a critical global environmental challenge. This study developed a sustainable strategy for synergistic nutrient removal and recovery by fabricating MgO-coated biochar (Mg-MBC600) through co-pyrolysis of municipal sludge and sunflower stalk (300–700 °C). Systematic investigations revealed temperature-dependent adsorption performance, with optimal nutrient removal achieved at 600 °C pyrolysis. The Mg-MBC600 composite exhibited enhanced physicochemical properties, including a specific surface area of 156.08 m2/g and pore volume of 0.1829 cm3/g, attributable to magnesium-induced structural modifications. Advanced characterization confirmed the homogeneous dispersion of MgO nanoparticles (~50 nm) across carbon matrices, forming active sites for chemisorption via electron-sharing interactions. The maximum adsorption capacities of Mg-MBC600 for nitrogen and phosphorus reached 84.92 mg/L and 182.27 mg/L, respectively. Adsorption kinetics adhered to the pseudo-second-order model, indicating rate-limiting chemical bonding mechanisms. Equilibrium studies demonstrated hybrid monolayer–multilayer adsorption. Solution pH exerted dual-phase control: acidic conditions (pH 3–5) favored phosphate removal through Mg3(PO4)2 precipitation, while neutral–alkaline conditions (pH 7–8) promoted NH4+ adsorption via MgNH4PO4 crystallization. XPS analysis verified that MgO-mediated chemical precipitation and surface complexation dominated nutrient immobilization. This approach establishes a circular economy framework by converting waste biomass into multifunctional adsorbents, simultaneously addressing sludge management challenges and enabling eco-friendly wastewater remediation. Full article
(This article belongs to the Special Issue Environmental Study of Waste Management: Life Cycle Assessment)
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