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17 pages, 4077 KiB  
Article
The Impact of Sm Promoter on the Catalytic Performance of Ni/Al2O3-SiO2 in Methane Partial Oxidation for Enhanced H2 Production
by Salwa B. Alreshaidan, Rasha S. A. Alanazi, Omalsad H. Odhah, Ahmed A. Ibrahim, Fekri Abdulraqeb Ahmed Ali, Naif Alarifi, Khaled M. Banabdwin, Sivalingam Ramesh and Ahmed S. Al-Fatesh
Catalysts 2025, 15(8), 721; https://doi.org/10.3390/catal15080721 (registering DOI) - 29 Jul 2025
Viewed by 277
Abstract
This study investigates the effects of samarium (Sm) promotion on the catalytic activity of 5 weight percent Ni catalysts for partial oxidation of methane (POM)-based hydrogen production supported on a Si-Al mixed oxide (10SiO2+90Al2O3) system. Several 5% [...] Read more.
This study investigates the effects of samarium (Sm) promotion on the catalytic activity of 5 weight percent Ni catalysts for partial oxidation of methane (POM)-based hydrogen production supported on a Si-Al mixed oxide (10SiO2+90Al2O3) system. Several 5% Ni-based catalysts supported on silica–alumina was used to test the POM at 600 °C. Sm additions ranged from 0 to 2 wt.%. Impregnation was used to create these catalysts, which were then calcined at 500 °C and examined using BET, H2-TPR, XRD, FTIR, TEM, Raman spectroscopy, and TGA methods. Methane conversion (57.85%) and hydrogen yield (56.89%) were greatly increased with an ideal Sm loading of 1 wt.%, indicating increased catalytic activity and stability. According to catalytic tests, 1 wt.% Sm produced high CH4 conversion and H2 production, as well as enhanced stability and resistance to carbon deposition. Nitrogen physisorption demonstrated a progressive decrease in pore volume and surface area with the addition of Sm, while maintaining mesoporosity. At moderate Sm loadings, H2-TPR and XRD analyses showed changes in crystallinity and increased NiO reducibility. Sm incorporation into the support and its impact on the ordering of carbon species were indicated by FTIR and Raman spectra. The optimal conditions to maximize H2 yield were successfully identified through optimization of the best catalyst, and there was good agreement between the theoretical predictions (87.563%) and actual results (88.39%). This displays how successfully the optimization approach achieves the intended outcome. Overall, this study demonstrates that the performance and durability of Ni-based catalysts for generating syngas through POM are greatly enhanced by the addition of a moderate amount of Sm, particularly 1 wt.%. Full article
(This article belongs to the Section Industrial Catalysis)
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27 pages, 2690 KiB  
Article
Adsorption of Methylene Blue on Metakaolin-Based Geopolymers: A Kinetic and Thermodynamic Investigation
by Maryam Hmoudah, Rosanna Paparo, Michela De Luca, Michele Emanuele Fortunato, Olimpia Tammaro, Serena Esposito, Riccardo Tesser, Martino Di Serio, Claudio Ferone, Giuseppina Roviello, Oreste Tarallo and Vincenzo Russo
ChemEngineering 2025, 9(4), 79; https://doi.org/10.3390/chemengineering9040079 - 25 Jul 2025
Viewed by 163
Abstract
Metakaolin-based geopolymers with different molar ratios of Si/Al were synthesized and utilized as an efficient adsorbent for the removal of methylene blue (MB) as a model cationic dye from aqueous solution. Various analytical techniques were employed to characterize the synthesized geopolymers. The influence [...] Read more.
Metakaolin-based geopolymers with different molar ratios of Si/Al were synthesized and utilized as an efficient adsorbent for the removal of methylene blue (MB) as a model cationic dye from aqueous solution. Various analytical techniques were employed to characterize the synthesized geopolymers. The influence of the main operation conditions on the adsorption kinetics of MB onto the geopolymer was examined under various operating conditions. Results showed a significant maximum MB adsorption capacity at the temperature of 30 °C for all four types of geopolymers studied (designated as A, B, C, and D) up to 35.3, 23.6, 25.5, and 19.0 mg g−1, respectively. The corresponding order of Si/Al ratio was A < C < B < D. Adsorption kinetics was so fast and reached equilibrium in 10 min, and the experimental results were described using the adsorption dynamic intraparticle model (ADIM). The equilibrium data for MB removal was in agreement with the Langmuir isotherm. Full article
(This article belongs to the Special Issue New Advances in Chemical Engineering)
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24 pages, 6934 KiB  
Article
In Situ High-Resolution Optical Microscopy Survey of the Initial Reactivity of Multiphase ZnAlMgSi Coating on Steel
by Guilherme Adinolfi Colpaert Sartori, Oumayma Gabsi, Tiago Machado Amorim, Viacheslav Shkirskiy and Polina Volovitch
Metals 2025, 15(8), 821; https://doi.org/10.3390/met15080821 - 23 Jul 2025
Viewed by 245
Abstract
The initial reactivity of a multiphase ZnAlMgSi coating with an Al content > 30 wt.% was studied by in situ reflective microscopy under alternating applied potentials +50 mV/−50 mV vs. open-circuit potential in 5 wt.% NaCl and 5 wt.% Na2SO4 [...] Read more.
The initial reactivity of a multiphase ZnAlMgSi coating with an Al content > 30 wt.% was studied by in situ reflective microscopy under alternating applied potentials +50 mV/−50 mV vs. open-circuit potential in 5 wt.% NaCl and 5 wt.% Na2SO4 aqueous solutions. In both environments, galvanic coupling between different coating phases and the anodic behavior decreased in the order binary ZnAl > binary Zn/Zn2Mg > Zn2Mg > Al(Zn); dendrites were evidenced for the coating exposed alone as well as in galvanic coupling with steel. Contrary to the observations known for Zn-rich ZnAlMg coatings, pure Zn2Mg was less reactive than the pure ZnAl phase, underlining the importance of the microstructure for reactivity. Si-needles were systematically cathodic, and Al(Zn) dendrites have shown cathodic behavior in some couplings. In the configuration of coupling with steel, corrosion started at the interfaces “binary ZnAl/steel substrate” or “binary ZnAl/Si particle”. The distribution and nature of the corrosion products formed during the experiment were assessed using X-ray microanalysis in scanning electron microscopy and confocal Raman microscopy. In the sulfate environment, a homogenous and stable corrosion product layer formed from the first steps of the degradation; this was in contrast to the chloride environment, where no surface film formed on the dendrites. Full article
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15 pages, 2939 KiB  
Article
Optimization of Process Parameters for WEDM Processing SiCp/Al Based on Graphene Working Fluid
by Zhou Sun, Weining Lei, Linglei Kong and Yafeng He
Processes 2025, 13(7), 2156; https://doi.org/10.3390/pr13072156 - 7 Jul 2025
Viewed by 311
Abstract
In the process of machining an aluminum matrix silicon carbide (SiCp/Al) composite material using wire electric discharge machining (WEDM), the thermal conductivity and dielectric properties of working fluid, such as discharge medium and cool carrier, directly determine the material removal rate (MRR) and [...] Read more.
In the process of machining an aluminum matrix silicon carbide (SiCp/Al) composite material using wire electric discharge machining (WEDM), the thermal conductivity and dielectric properties of working fluid, such as discharge medium and cool carrier, directly determine the material removal rate (MRR) and surface roughness (Ra). In this paper, graphene-working fluid is innovatively used as working medium to optimize the discharge process due to its high thermal conductivity and field emission characteristics. The single-factor experiments show that graphene can increase the MRR by 11.16% and decrease the Ra by 29.96% compared with traditional working fluids. In order to analyze the multi-parameter coupling effect, an L16 (44) orthogonal test is further designed, and the effects of the pulse width (Ton), duty cycle (DC), power tube number (PT), and wire speed (WS) on the MRR and Ra are determined using a signal-to-noise analysis. Based on a gray relational grade analysis, a multi-objective optimization model was established, and the priority of the MRR and Ra was determined using an AHP, and finally the optimal parameter combination (Ton = 22 μs, DC = 1:4, PT = 3, WS = 2) was obtained. Full article
(This article belongs to the Special Issue Processes in 2025)
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16 pages, 8495 KiB  
Article
Utilization of Waste Clay–Diatomite in the Production of Durable Mullite-Based Insulating Materials
by Svetlana Ilić, Jelena Maletaškić, Željko Skoko, Marija M. Vuksanović, Željko Radovanović, Ivica Ristović and Aleksandra Šaponjić
Appl. Sci. 2025, 15(13), 7512; https://doi.org/10.3390/app15137512 - 4 Jul 2025
Viewed by 271
Abstract
Microstructural, mechanical and qualitative phase identification of durable mullite-based ceramics obtained by utilization of waste clay–diatomite has been studied. Mullite-based ceramics were fabricated using waste clay–diatomite from the Baroševac open-cast coal mine, Kolubara (Serbia). The raw material consists mainly of SiO2 (70.5 [...] Read more.
Microstructural, mechanical and qualitative phase identification of durable mullite-based ceramics obtained by utilization of waste clay–diatomite has been studied. Mullite-based ceramics were fabricated using waste clay–diatomite from the Baroševac open-cast coal mine, Kolubara (Serbia). The raw material consists mainly of SiO2 (70.5 wt%) and a moderately high content of Al2O3 (13.8 wt%). In order to achieve the stoichiometric mullite composition (3Al2O3-2SiO2), the raw material was mixed with an appropriate amount of Al(NO3)3·9H2O. After preparing the precursor powder, the green compacts were sintered at 1300, 1400 and 1500 °C for 2 h. During the process, rod-shaped mullite grains were formed, measuring approximately 5 µm in length and a diameter of 500 nm (aspect ratio 10:1). The microstructure of the sample sintered at 1500 °C resulted in a well-developed, porous, nest-like morphology. According to the X-ray diffraction analysis, the sample at 1400 °C consisted of mullite, cristobalite and corundum phases, while the sample sintered at 1500 °C contained mullite (63.24 wt%) and an amorphous phase that reached 36.7 wt%. Both samples exhibited exceptional compressive strength—up to 188 MPa at 1400 °C. However, the decrease in compressive strength to 136 MPa at 1500 °C is attributed to changes in the phase composition, the disappearance of the corundum phase and alterations in the microstructure. This occurred despite an increase in bulk density to 2.36 g/cm3 (approximately 82% of theoretical density) and a complete reduction in open porosity. The residual glassy phase (36.7 wt% at 1500 °C) is probably the key factor influencing the mechanical properties at room temperature in these ceramics produced from waste clay–diatomite. However, the excellent mechanical stability of the samples sintered at 1400 and 1500 °C, achieved without binders or additives and using mined diatomaceous earth, supports further research into mullite-based insulating materials. Mullite-based materials obtained from mining waste might be successfully used in the field of energy-efficient refractory materials and thermal insulators. for high-temperature applications Full article
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17 pages, 921 KiB  
Article
Adsorption–Desorption Behaviour of Imidacloprid, Thiamethoxam, and Clothianidin in Different Agricultural Soils
by Gabriela Briceño, Graciela Palma, Heidi Schalchli, Paola Durán, Cesar Llafquén, Andrés Huenchupán, Carlos Rodríguez-Rodríguez and María Cristina Diez
Agriculture 2025, 15(13), 1380; https://doi.org/10.3390/agriculture15131380 - 27 Jun 2025
Viewed by 370
Abstract
This study evaluated the adsorption and desorption of imidacloprid (IMI), thiamethoxam (THM) and clothianidin (CLO) in an andisol (Freire soil) and an inceptisol (Chufquén soil) from southern Chile with different organic matter and clay contents. The soils had a slightly acidic pH and [...] Read more.
This study evaluated the adsorption and desorption of imidacloprid (IMI), thiamethoxam (THM) and clothianidin (CLO) in an andisol (Freire soil) and an inceptisol (Chufquén soil) from southern Chile with different organic matter and clay contents. The soils had a slightly acidic pH and clay and clay-loam textures. The tests were carried out at 20 °C with CaCl2 0.01 M as the electrolyte. Kinetic experiments were performed and isotherms were fitted to the pseudo-second-order, Elovich, Weber–Morris, Freundlich and Langmuir models. The kinetics were best described by the pseudo-second-order model (R2 > 0.99), indicating chemisorption; the rate was the highest for THM, although IMI and CLO achieved the highest retention capacities. The Chufquén samples, with lower organic matter but 52% clay, exhibited the highest Kf and qm of up to 12.4 and 270 mg kg−1, respectively, while the Kd (2.3–6.9 L kg−1) and Koc (24–167 L kg−1) coefficients revealed a moderate leaching risk. THM was the most mobile compound due to its high solubility. Desorption was partially irreversible (H = 0.48–1.48), indicating persistence in soil. FTIR analysis confirmed the interaction with O-Al-O/O-O-Si-O groups without alterations in the mineral structure. In the soils examined in this study, the clay fraction and variable-charge minerals, rather than organic matter, were more closely associated with the adsorption behaviour of these NNIs. Full article
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15 pages, 5316 KiB  
Article
Sea Sand as a Silica Source to Hydrothermally Synthesize Analcime
by Wei Xie, Hao Ma, Chuangguang Cao, Yating Wang, Yanhui Qiao, Junjiang Teng, Ning Li and Chaochao Yue
Materials 2025, 18(12), 2818; https://doi.org/10.3390/ma18122818 - 16 Jun 2025
Viewed by 320
Abstract
Analcime has demonstrated potential for a variety of applications in technology, especially in adsorption and heterogeneous catalysis. In this study, synthetic analcime was investigated by using sea sand as a silica source. Sea sand was first treated with HNO3 and NaOH. The [...] Read more.
Analcime has demonstrated potential for a variety of applications in technology, especially in adsorption and heterogeneous catalysis. In this study, synthetic analcime was investigated by using sea sand as a silica source. Sea sand was first treated with HNO3 and NaOH. The pretreated sea sand as the silica resource and Al(NO3)3 as the aluminum source were used for the hydrothermal synthesis of analcime with different ratios of Si/Al and Na/Si. The products obtained under different conditions were characterized by X-ray diffraction. The results showed that analcime synthesized using acid-treated sea sand was mixed with other impurities, such as quartz and sodalite. Pure analcime was obtained using alkali-treated sea sand as the silica source. The analcime prepared under an optimized synthesis condition was further investigated via SEM, FT-IR, and TG. The particle size of the prepared analcime ranged from 40 to 50 μm. The adsorption ability of analcime was studied, and the Cu2+ adsorption process was found to follow a pseudo-second-order kinetic model. Full article
(This article belongs to the Special Issue Application and Modification of Clay Minerals)
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15 pages, 1687 KiB  
Article
Study on Regulation Mechanism of Heat Transport at Aluminum Nitride/Graphene/Silicon Carbide Heterogeneous Interface
by Dongjing Liu, Pengbo Wang, Zhiliang Hu, Jia Fu, Wei Qin, Jianbin Yu, Yangyang Zhang, Bing Yang and Yunqing Tang
Nanomaterials 2025, 15(12), 928; https://doi.org/10.3390/nano15120928 - 14 Jun 2025
Viewed by 435
Abstract
In order to solve the self-heating problem of power electronic devices, this paper adopts a nonequilibrium molecular dynamics approach to study the thermal transport regulation mechanism of the aluminum nitride/graphene/silicon carbide heterogeneous interface. The effects of temperature, size, and vacancy defects on interfacial [...] Read more.
In order to solve the self-heating problem of power electronic devices, this paper adopts a nonequilibrium molecular dynamics approach to study the thermal transport regulation mechanism of the aluminum nitride/graphene/silicon carbide heterogeneous interface. The effects of temperature, size, and vacancy defects on interfacial thermal conductivity are analyzed by phonon state density versus phonon participation rate to reveal their phonon transfer mechanisms during thermal transport. It is shown that the interfacial thermal conductance (ITC) increases about three times when the temperature increases from 300 K to 1100 K. It is analyzed that the increase in temperature will enhance lattice vibration, enhance phonon coupling degree, and thus increase its ITC. With the increase in the number of AlN-SiC layers from 8 to 28, the ITC increases by about 295.3%, and it is analyzed that the increase in the number of AlN-SiC layers effectively reduces the interfacial scattering and improves the phonon interfacial transmission efficiency. The increase in the number of graphene layers from 1 layer to 4 layers decreases the ITC by 70.3%. The interfacial thermal conductivity reaches a minimum, which is attributed to the increase in graphene layers aggravating the degree of phonon localization. Under the influence of the increase in graphene single and double vacancy defects concentration, the ITC is slightly reduced. When the defect rate reaches about 20%, the interfacial thermal conductance of SV (single vacancy) and DV (double vacancy) defects rises back to 5.606 × 10−2 GW/m2K and 5.224 × 10−2 GW/m2K, respectively. It is analyzed that the phonon overlapping and the participation rate act at the same time, so the heat-transferring phonons increase, increasing the thermal conductance of their interfaces. The findings provide theoretical support for optimizing the thermal management performance of heterostructure interfaces. Full article
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23 pages, 15965 KiB  
Article
Parametric Optimization of Dry Sliding Wear Attributes for AlMg1SiCu Hybrid MMCs: A Comparative Study of GRA and Entropy-VIKOR Methods
by Krishna Prafulla Badi, Srinivasa Rao Putti, Maheswara Rao Chapa and Muralimohan Cheepu
J. Compos. Sci. 2025, 9(6), 297; https://doi.org/10.3390/jcs9060297 - 10 Jun 2025
Viewed by 503
Abstract
In recent days, aluminum-based hybrid composites have garnered more interest than monolithic alloys owing to their remarkable properties, encompassing a high strength-to-weight ratio, excellent corrosion resistance, and impressive wear durability. The present study attempts to optimize the multiple wear attribute characteristics of Al6061/SiC/Al [...] Read more.
In recent days, aluminum-based hybrid composites have garnered more interest than monolithic alloys owing to their remarkable properties, encompassing a high strength-to-weight ratio, excellent corrosion resistance, and impressive wear durability. The present study attempts to optimize the multiple wear attribute characteristics of Al6061/SiC/Al2O3 hybrid composites using grey and entropy-based VIKOR techniques. The composites were produced by adding equal proportions of SiC/Al2O3 (0–12 wt.%) ceramics through the stir-casting process, using an ultrasonication setup. Dry sliding wear experiments were executed with tribometer variants, namely reinforcement content (wt.%), load (N), sliding velocity (v), and sliding distance (SD), following L27 OA. The optimal combination of process variables for achieving high GRG values from grey analysis was found to be A3-B3-C3-D3. The S/N ratios and ANOVA results for GRG indicated that RF content (wt.%) is the predominant component determining multiple outcomes, followed by sliding distance, load, and sliding velocity. The multi-order regression model formulated for the VIKOR index (Qi) displayed high significance and more accuracy, with a variance of 0.0216 and a coefficient of determination (R2), and adjusted R2 values of 99.60% and 99.14%. Subsequent morphological studies indicated that plowing, abrasion, and adhesion mechanisms are the dominant modes of wear. Full article
(This article belongs to the Special Issue Recent Progress in Hybrid Composites)
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20 pages, 3820 KiB  
Article
Improvement of Anti-Collision Performance of Concrete Columns Using Bio-Inspired Honeycomb Column Thin-Walled Structure (BHTS)
by Jingbo Wang, Hongxiang Xia and Shijie Wang
Biomimetics 2025, 10(6), 355; https://doi.org/10.3390/biomimetics10060355 - 1 Jun 2025
Viewed by 369
Abstract
In recent years, frequent vehicle–bridge pier collision accidents have posed a serious threat to people’s economic and life security. In order to avert the impairment of reinforced concrete bridge piers (RCBPs) under the impact of vehicles, three kinds of Mg–Al alloy AlSi10Mg anti-collision [...] Read more.
In recent years, frequent vehicle–bridge pier collision accidents have posed a serious threat to people’s economic and life security. In order to avert the impairment of reinforced concrete bridge piers (RCBPs) under the impact of vehicles, three kinds of Mg–Al alloy AlSi10Mg anti-collision structures designed by selective laser melting (SLM) printing were tested by the numerical simulation method in this study: an ultra-high performance concrete (UHPC) anti-collision structure, a bio-inspired honeycomb column thin-walled structure (BHTS) buffer interlayer, and a UHPC–BHTS composite structure were used to reduce the damage degree of RCBPs caused by vehicle impact. In accordance with the prototype configuration of the pier, a scaled model with a scale ratio of 1:10 was fabricated. Three anti-collision structures were installed on the reinforced concrete (RC) column specimens for the steel ball impact test. The impact simulation under low-energy and high-energy input was carried out successively, and the protective effect of the three anti-collision devices on the RC column was comprehensively evaluated. The outcomes demonstrate that the BHTS buffer interlayer and the UHPC–BHTS composite structure are capable of converting the shear failure of RC columns into bending failure, thereby exerting an efficacious role in safeguarding RC columns. The damage was evaluated under all impact conditions of BHTS and UHPC–BHTS composite structures, and the RC column only suffered slight damage, while the RC column without protective measures and the RC column with the UHPC anti-collision structure alone showed serious damage and collapse behavior. This approach can offer a valuable reference for anti-collision design within analogous projects. Full article
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22 pages, 12129 KiB  
Article
Metallogenic Age and Tectonic Setting of the Haigou Gold Deposit in Southeast Jilin Province, NE China: Constraints from Magmatic Chronology and Geochemistry
by Zhongjie Yang, Yuandong Zhao, Cangjiang Zhang, Chuantao Ren, Qun Yang and Long Zhang
Minerals 2025, 15(6), 582; https://doi.org/10.3390/min15060582 - 29 May 2025
Viewed by 374
Abstract
Haigou deposit, located in Dunhua City, southeast Jilin Province, NE China, is a large-scale gold deposit. The gold ore body is categorized into two types: quartz-vein type and altered rock type, with the quartz-vein type being predominant. The vein gold ore body primarily [...] Read more.
Haigou deposit, located in Dunhua City, southeast Jilin Province, NE China, is a large-scale gold deposit. The gold ore body is categorized into two types: quartz-vein type and altered rock type, with the quartz-vein type being predominant. The vein gold ore body primarily occurs within the monzonite granite and monzonite rock mass in the Haigou area and is controlled by fault structures trending northeast, northwest, and near north-south. In order to constrain the age and tectonic setting of quartz vein-type gold mineralization, we conducted a detailed underground investigation and collected samples of monzonite granite and pyroxene diorite porphyrite veins related to quartz-vein-type gold mineralization for LA-ICP-MS zircon U-Pb dating and whole-rock main trace element data testing to confirm that monzonite granite is closely related to gold mineralization. Pyroxene diorite porphyry and gold mineralization were found in parallel veins. The zircon U-Pb weighted mean ages of monzonite and pyroxene diorite porphyrite veins are 317.1 ± 3.5 Ma and 308.8 ± 3.0 Ma, respectively, indicating that gold mineralization in monzonite, pyroxene diorite porphyrite veins, and quartz veins occurred in the Late Carboniferous. The monzonite granite and pyroxene diorite porphyrite veins associated with quartz vein-type gold mineralization have high SiO2, high K, and high Al2O3 and are all metaluminous high-potassium calc-alkaline rock series. Both of them are relatively enriched in light rare earth elements (LREE) and macroionic lithophile elements (LILE: Rb, Ba, K, etc.), but deficient in heavy rare earth elements (HREE) and high field strength elements (HFSE: Nb, Ta, P, Ti, etc.), the monzonitic granite Eu is a weak positive anomaly (δEu = 1.15–1.46), the pyroxene diorite porphyre dyke Eu is a weak positive anomaly (δEu = 1.09–1.13), and the Nb and Ta are negative anomalies. The Th/Nb values are 0.28–0.73 and 1.48–2.05, and La/Nb are 2.61–4.74 and 4.59–5.43, respectively, suggesting that diagenetic mineralization is the product of subduction in an active continental margin environment. In recent years, scholarly research on Sr, Nd, and Pb isotopes in Haigou rock masses has indicated that the magmatic source region in the Haigou mining areas is complex. It is neither a singular crustal source nor a mantle source but rather a mixed crust-mantle source, primarily resulting from the partial melting of lower crustal materials, with additional contributions from mantle-derived materials. In summary, the metallogenic characteristics, chronology data, geochemical characteristics, and regional tectonic interpretation indicate that at least one phase of magmatic-hydrothermal gold mineralization was established in the Late Carboniferous as a result of the subduction of the Paleo-Asian ocean plate at the northern margin of the North China Craton. Full article
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17 pages, 4788 KiB  
Article
Preparation of Phenolic Epoxy-Based Electronic Packaging Materials with High Thermal Conductivity by Creating an Interfacial Heat Conduction Network
by Minghao Ye, Jing Jiang, Lin Zhao, Hongyu Zhu, Junjie Wang, Zicai Sun, Dewei Zhang, Ming Li and Yagang Zhang
Polymers 2025, 17(11), 1507; https://doi.org/10.3390/polym17111507 - 28 May 2025
Viewed by 456
Abstract
As one of the most widely used packaging materials, epoxy composite (EP) offers excellent insulation properties; however, its intrinsic low thermal conductivity (TC) limits its application in high-frequency and high-power devices. To enhance the TC of EP, six highly thermally conductive inorganic fillers, [...] Read more.
As one of the most widely used packaging materials, epoxy composite (EP) offers excellent insulation properties; however, its intrinsic low thermal conductivity (TC) limits its application in high-frequency and high-power devices. To enhance the TC of EP, six highly thermally conductive inorganic fillers, namely, Al2O3, MgO, ZnO, Si3N4, h-BN, and AlN, were incorporated into the EP matrix at varying contents (60–90 wt.%). The resulting epoxy molding compounds (EMCs) demonstrated significant improvement in thermal conductivity coefficient (λ) at high filler contents (90 wt.%), ranging from 0.67 W m−1 K−1 to 1.19 W m−1 K−1, compared to the pristine epoxy composite preform (ECP, 0.36 W m−1 K−1). However, it was found that the interfacial thermal resistance (ITR) between EP and filler materials is a major hindrance restricting TC improvement. In order to address this challenge, graphene nanosheets (GNSs) and carbon nanotubes (CNTs) were introduced as additives to reduce the ITR. The experimental results indicated that CNTs were effective in enhancing the TC, with the optimized EMC achieving a λ value of 1.14 W m−1 K−1 using 60 wt.% Si3N4 + 2 wt.% CNTs. Through the introduction of a small amount of CNT (2 wt.%), the inorganic filler content was significantly reduced from 90 wt.% to 60 wt.% while still maintaining high thermal conductivity (1.14 W m−1 K−1). We propose that the addition of CNTs helps in the construction of a partial heat conduction network within the EP matrix, thereby facilitating interfacial heat transfer. Full article
(This article belongs to the Special Issue Fiber-Reinforced Polymer Composites: Progress and Prospects)
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20 pages, 5360 KiB  
Article
Highly Efficient Removal of Cadmium from Wastewater Using Eco-Friendly and Cost-Effective Amorphous Silicoaluminophosphates as Adsorbent Particles
by Hamza Annath, Oluwafikayo Jaiyeola and Chirangano Mangwandi
Separations 2025, 12(5), 128; https://doi.org/10.3390/separations12050128 - 16 May 2025
Viewed by 805
Abstract
This article presents a study on the development of amorphous aluminophosphate (Am-AlP) and silico-aluminophosphate (Am-SiAlP) materials for the removal of cadmium (Cd) from wastewater. Cadmium is a toxic heavy metal that poses significant environmental and health risks, and its removal from water sources [...] Read more.
This article presents a study on the development of amorphous aluminophosphate (Am-AlP) and silico-aluminophosphate (Am-SiAlP) materials for the removal of cadmium (Cd) from wastewater. Cadmium is a toxic heavy metal that poses significant environmental and health risks, and its removal from water sources is crucial. This study explores the synthesis of these materials, focusing on the impact of silicon content on their adsorption properties. The materials were characterized using various techniques, including FTIR, XRD, TGA, and BET analysis, which revealed that the incorporation of silicon increased the surface area and porosity of the adsorbents, enhancing their cadmium removal efficiency. The Am-SiAlP (7.5) sample, with a 7.5 mol% Si content, showed the highest adsorption capacity (52.63 mg g−1) and removal efficiency (93%). Kinetic studies revealed that over 90% of cadmium was removed within the first 30 min, indicating rapid adsorption capabilities. The adsorption process was found to follow a pseudo-second-order kinetic model, indicating chemisorption as the rate-limiting step. The Langmuir isotherm model best described the adsorption, suggesting monolayer adsorption of cadmium on the adsorbent surface. This study also investigated the effect of interfering ions, showing that while the presence of other ions slightly reduced the adsorption efficiency, the Am-SiAlP (7.5) material still performed well. This research concludes that Am-SiAlP materials, particularly Am-SiAlP (7.5), are promising adsorbents for cadmium removal due to their high efficiency, cost-effectiveness, and environmental friendliness. Full article
(This article belongs to the Special Issue Adsorption/Degradation Methods for Water and Wastewater Treatment)
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14 pages, 5095 KiB  
Article
Performance Study of CaO-CaF2- and CaO-Al2O3-SiO2-Based High-Efficiency Desulfurizers
by Ruihong Cao, Shengtao Qiu, Ting Wu and Haijun Wang
Metals 2025, 15(5), 550; https://doi.org/10.3390/met15050550 - 16 May 2025
Viewed by 369
Abstract
In order to reduce the content of harmful impurity sulfur elements in steel to meet the quality requirements of high value-added steel, efficient desulfurization of RH vacuum degassing is essential. Based on the simplex lattice composition design method, the effects of typical compositions [...] Read more.
In order to reduce the content of harmful impurity sulfur elements in steel to meet the quality requirements of high value-added steel, efficient desulfurization of RH vacuum degassing is essential. Based on the simplex lattice composition design method, the effects of typical compositions on liquidus temperature, sulfur capacity, melting temperature, the effects of typical compositions on liquidus temperature, sulfur capacity, melting temperature, viscosity, and desulfurization rate of CaO-CaF2- and CaO-Al2O3-SiO2-based desulfurizers were studied by thermodynamic calculation, the melting temperature test, and the slag–steel contact experiment. The results show that in CaO-CaF2- and CaO-Al2O3-SiO2-based desulfurizers, the changes in CaF2, MgO, and Al2O3 contents has little effect on the equilibrium S content of molten steel at lower SiO2 contents, whereas, at higher SiO2 contents, the equilibrium S content of the molten steel is greatly increased when the CaF2, MgO, and Al2O3 content is greater than a certain value. Meanwhile, the increase in CaF2 and MgO content reduces the high-temperature viscosity and breaking temperature (corresponding to the turning point on the viscosity–temperature curve) to varying degrees, which results in a better slag fluidity and is favorable to the prevention of crusting. With the increase in Al2O3 and SiO2 content, the breaking temperature of the CaO-CaF2-based desulfurizer is significantly reduced, which is beneficial to preventing crust. However, when the breaking temperature of CaO-Al2O3-SiO2-based desulfurizer increases, part of the slag system has solidified at 1400 °C, which is easy to lead to slag crust when the temperature drops. Comprehensively, for the CaO-CaF2-based desulfurizer, CaO = 60 wt%, CaF2 = 30 wt%, SiO2 = 0–5 wt%, and add a small amount of Al2O3 and MgO, its desulfurization effect is significant. For the CaO-Al2O3-SiO2-based desulfurizer, CaO = 39–57 wt%, Al2O3 = 20–35 wt%, SiO2 = 10–15 wt%, MgO = 4 wt%, CaF2 = 4–8 wt%, its desulfurization effect meets the demand, and it can reduce equipment erosion and environmental pollution. Full article
(This article belongs to the Special Issue Green Super-Clean Steels)
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12 pages, 4511 KiB  
Article
Assessment of Feldspars from Central Portugal Pegmatites for Sustainable Ceramic Applications
by Carla Candeias, Adga Gomes and Fernando Rocha
Minerals 2025, 15(5), 527; https://doi.org/10.3390/min15050527 - 15 May 2025
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Abstract
This study investigates the mineralogical, chemical, and fusibility characteristics of feldspar samples collected from eight pegmatitic bodies in central Portugal. The primary aim was to evaluate their suitability for use in ceramic applications, driven by the need to valorize local georesources, reduce dependence [...] Read more.
This study investigates the mineralogical, chemical, and fusibility characteristics of feldspar samples collected from eight pegmatitic bodies in central Portugal. The primary aim was to evaluate their suitability for use in ceramic applications, driven by the need to valorize local georesources, reduce dependence on imported raw materials, and contribute to the sustainability and competitiveness of the Portuguese ceramic sector. Samples were analyzed by X-Ray Diffraction (XRD), X-ray Fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Firing tests were performed to assess fusibility, whiteness, and visible impurity behavior. Results indicate that seven of the eight samples were dominated by a combination of microcline and albite, with minor amounts of quartz and muscovite. Crystallinity indices varied across samples, reflecting differences in mineral order and thermal reactivity. Chemical compositions showed acceptable levels of SiO2 and Al2O3, and total alkali contents (Na2O + K2O) between 10% and 16%, aligning with industrial standards for ceramic raw materials. The Fe2O3 contents were below 0.3% in most samples, suggesting favorable conditions for whiteness upon firing. Loss on ignition (LOI) values were generally low, except for one sample rich in muscovite. Fusibility behavior varied significantly between samples, with albite-rich samples showing lower melting points and better flow characteristics, while microcline-dominant samples required higher temperatures for vitrification but contributed to structural stability. The K2O/Na2O ratio presented values favoring earlier softening and fluxing. Whiteness revealed that samples with low Fe2O3 and TiO2 content, particularly those with low mica content, achieved the best aesthetic outcomes post-firing. Full article
(This article belongs to the Collection Clays and Other Industrial Mineral Materials)
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