Search Results (5,815)

This study investigates the influence of various manganese sources—specifically MnCO₃, Mn₃O₄, and MnO₂—on the performance of lithium manganese iron phosphate (LMFP) synthesized through a combined spray-drying and chemical vapor deposition (CVD) strategy. The synthesis protocol involved the initial formation of a precursor through the co-sintering of manganese, phosphorus, iron, and dopant sources via CVD, followed by secondary spray-drying and carbon thermal reduction with Li₂CO₃ and carbon additives. Morphological analysis via Scanning Electron Microscopy (SEM) and laser diffraction indicates that Mn₃O₄-derived LMFP possesses highly spherical secondary structures comprising well-crystallized, uniformly distributed primary particles. Elemental mapping via Energy Dispersive Spectroscopy (EDS) confirms a homogeneous distribution of stoichiometric elements without localized segregation, alongside the successful lattice integration of dopants. In contrast, the MnCO₃-derived samples exhibited deleterious carbon accumulation on the primary particle surfaces. Consequently, the Mn₃O₄-based LMFP demonstrated superior electrochemical kinetics, delivering a remarkable initial discharge capacity of 148.9 mAh g⁻¹ at 1C, with an exceptional capacity retention of 97.9% after 100 cycles. These findings underscore the critical role of precursor selection in optimizing the interfacial and bulk properties of high-performance LMFP cathodes. Full article

This paper investigates the stability of perovskite films under bonding conditions, focusing on the impact of bonding temperature on the electrical, morphological, and elemental characteristics of perovskite solar cells (PSCs) incorporating a barium–strontium titanate (BST) barrier layer. This study aimed to elucidate the interdiffusion phenomena at interfaces and their effect on device performance. We found that increasing the bonding temperature significantly degrades PSC performance, with efficiencies dropping from 21% at 100 °C to 65% at 180 °C relative to unbonded devices. A critical bonding temperature of 150 °C was identified, which correlates with a pronounced drop in short-circuit current and a peak in series resistance, phenomena primarily attributed to severe elemental interdiffusion and defect formation at the interfaces. Morphological (SEM) and elemental (EDS) analyses confirmed the temperature-dependent nature of interdiffusion across the Au/BST/perovskite interfaces. These findings underscore the critical role of bonding temperature in triggering interfacial degradation, a factor that mediates the stability of BST-interfaced PSCs during packaging. Full article

Sustainable valorization of biomass through hydrothermal carbonization (HTC) represents an environmentally benign method for producing carbon materials for water treatment applications. This research aims to optimize the production of hydrochar from waste food by focusing on parameter optimization, physicochemical characterization, and the capacity of hydrochar to act as an adsorbent for the removal of the copper (II) ion from polluted water. A design of experiments using the RSM approach was employed to evaluate and optimize the influence of carbonization temperature, ranging from 180 to 250 °C, with a residence time of 2–5 h. The predictive ability of the MINITAB-generated model was close to accurate, as demonstrated by the design application for process simulation. The maximum % hydrochar yield was 72.65% for the experimental yield and 71.53% for the predicted yield, both obtained from a sample carbonized at 166 °C for 3.5 h. Batch adsorption experiments were conducted to assess the hydrochar’s ability to remove Cu²⁺ from aqueous solutions, and the Langmuir and the Freundlich isotherms were fitted at different pH levels. A comprehensive characterization of the produced hydrochar was conducted using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM-EDS). The results revealed significant modifications in surface morphology, pore development, and the presence of oxygen-containing functional groups. Based on the findings in this report, it is safe to conclude that hydrochar derived from food waste could serve as a potential adsorbent. Overall, the study demonstrates that sustainable hydrochar production from biomass can simultaneously address waste management challenges and provide an efficient solution for heavy metal removal, thereby advancing circular bioeconomy and environmental protection. Full article

Thaumasite sulfate attack (TSA) under elevated water pressure has important implications for the durability of deep underground concrete structures, yet the deterioration process and the coupled effect of water pressure and carbonate supply remain insufficiently understood. In this study, laboratory pressurized sulfate exposure tests were conducted to investigate the evolution of macroscopic performance and microstructure of cement mortars with different limestone powder contents (0%, 15%, and 30%) under water pressures of 0, 2.5, and 5.0 MPa. The results show that elevated water pressure promotes sulfate ingress into the mortar and accelerates later-stage strength loss; this interpretation is supported by the depth-dependent distribution of soluble SO₄²⁻ measured in mortars without limestone powder. Two-way ANOVA indicates that both water pressure and limestone powder content have significant effects on compressive strength, and their interaction becomes statistically significant at 120 d. XRD, FT-IR, and SEM/EDS results show that, under elevated water pressure and high limestone powder content, the corrosion products gradually evolve from gypsum-related products to ettringite- and thaumasite-related products, with a certain spatial differentiation. Specifically, the gray–white, mud-like surface products are consistent with thaumasite-rich assemblages, whereas the needle- and column-like crystals in the interior are consistent with ettringite-rich assemblages. Overall, elevated water pressure mainly promotes sulfate transport, while limestone powder mainly increases carbonate availability. These two factors may jointly intensify TSA deterioration in mortar through a pathway involving transport enhancement, carbonate supply, corrosion product evolution, and aggravated macroscopic damage. This study provides a reference for understanding the sulfate deterioration mechanism of limestone powder-containing cement-based materials in deep underground environments under elevated water pressure. Full article

Two hemostatic bionanocomposite dressings were developed using natural, semi-natural (or semi-synthetic) and synthetic polymers. The first system consisted of chitosan (CS), polyvinyl alcohol (PVA), and carboxymethyl cellulose (CMC) (CS/PVA/CMC), while the second was based on CS, PVA, and starch (SR) (CS/PVA/SR). Zinc oxide (ZnO) nanoparticles and bicyclic monoterpene camphor (CP) ketone were incorporated as bioactive agents in order to enhance antimicrobial and hemostatic performance. FTIR spectroscopy confirmed the successful solvent casting synthesis of the dressings and the interactions between the biopolymers and additives. XRD analysis indicated a predominantly amorphous structure, while SEM images and EDS analysis revealed uniform dispersion of ZnO particles within the polymer matrices without aggregation. Furthermore, the CS/PVA/CMC-1ZnO/CP sample exhibited a water sorption of 12,666 ± 126%, while CS/PVA/SR-1ZnO/CP reached 7013 ± 215%. ZnO incorporation also improved mechanical performance, with CS/PVA/SR-2ZnO/CP displaying the highest tensile strength (39.18 ± 0.2 MPa) and elongation at break (9.54 ± 1.04%). ZnO incorporation also led to a concentration-dependent increase in antibacterial activity, with SR-based dressings achieving near-complete bacterial reduction at higher ZnO loadings. All the dressings demonstrated good biocompatibility, while CS/PVA/SR-1ZnOCP showed the fastest clotting time (420s ± 40), highlighting its potential for hemostatic applications. Full article

Concentrated Solar Power (CSP) tower systems require receiver materials capable of operating above 1000 °C to meet the efficiency targets of third-generation technologies (25–30%). Hybrid solutions, combining ceramic coatings with metallic substrates, offer promising thermomechanical stability under severe thermal cycling. This study investigates the high-temperature behavior of silicon carbide (SiC) coatings deposited on Fe-C-Al-Mo alloys under concentrated solar flux. Substrates were pre-oxidized to form a continuous 1–2 µm α-Al₂O₃ interlayer, serving as a chemical and mechanical buffer. SiC coatings (10–24 µm thick) were deposited via High-Temperature Chemical Vapor Deposition (HT-CVD). Characterization using XRD, SEM, EDS, and optical spectrophotometry identified cubic 3C-SiC with a globular microstructure and high compressive residual stresses (−2000 to −2400 MPa), inducing microcracking. Stress relaxation was achieved by increasing coating thickness or post-deposition annealing. Controlled oxidation formed a thin silica layer, enhancing solar absorptivity to over 90%. Accelerated thermal cycling (up to ~900 kW/m², 1050–1200 °C) revealed that coating stability depends on SiC thickness, residual stress evolution, α-Al₂O₃ interlayer thickness, and cycling severity. Optimizing these parameters is essential for ensuring the long-term durability of hybrid CSP receivers. Full article

Metakaolin-based geopolymers modified with ZnO and surface-functionalized ZnO were developed and investigated in terms of structure, morphology, textural properties, and photocatalytic performance. ZnO, ZnO@AS(zinc oxide functionalized with steric acid), and ZnO@PEG(zinc oxide functionalized with polyethylene glycol) were incorporated into the geopolymer matrix and characterized by XRD(X-ray diffraction), ATR–FTIR(Fourier transform infrared spectroscopy in attenuated total reflectance, SEM–EDS( scanning electron microscopy coupled with spectroscopy with energy-dispersive X-ray spectroscopy), and BET(Brunauer–Emmett–Teller) analysis. The results showed that ZnO incorporation did not significantly modify the amorphous aluminosilicate network but affected the morphology and porosity depending on the functionalization method. ZnO@AS induced matrix densification and reduced accessible porosity, while ZnO@PEG improved particle dispersion and preserved the porous structure. Among the ZnO-modified metakaolin-based geopolymers, GP/ZnO@PEG(geopolymer with ZnO@PEG particles) exhibited the highest photocatalytic performance, characterized by a BET surface area of 17.22 m²/g, an apparent kinetic constant of 0.01668 min⁻¹, and a half-life of approximately 41 min, achieving approximately 90% methylene blue removal after 120 min of UV-A irradiation. The study demonstrates that ZnO surface functionalization controls the interfacial interaction with the geopolymer matrix and plays a key role in the performance of geopolymer-based photocatalytic materials. Full article

This study investigates the synthesis and kinetic behavior of a magnetic biochar derived from avocado seed biomass for the removal of hexavalent chromium (Cr(VI)) from aqueous solutions. Magnetite (Fe₃O₄) was synthesized through different routes, including nitrogen-assisted coprecipitation, redox-controlled coprecipitation, polyol, sol–gel, and sonochemical methods, to evaluate their structural properties and iron incorporation efficiency. Based on compositional and crystallographic analyses, the coprecipitation under an inert atmosphere exhibited improved phase purity and higher Fe₃O₄ content, which was selected for in situ incorporation onto biochar produced by pyrolysis at 450 °C. The resulting magnetic material and composite were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS), confirming the suitability of the synthesis method and the successful deposition of magnetite onto the porous carbon matrix while preserving its structural integrity. Batch adsorption experiments were conducted at pH 2.0 to evaluate the effect of adsorbent dose and initial Cr(VI) concentration. The adsorption process reached equilibrium within 120 min and was better described by the pseudo-second-order kinetic model (R² ≥ 0.98), suggesting that chemisorption governs the rate-controlling step, with diffusion phenomena contributing but not dominating the overall mechanism. The maximum adsorption capacity predicted by the kinetic model reached 42.49 mg g⁻¹ at an initial concentration of 100 mg L⁻¹. The results demonstrate that avocado-seed-derived magnetic biochar represents a sustainable and effective material for chromium-contaminated water treatment, integrating agro-industrial waste valorization with enhanced adsorption performance and magnetic separability. Full article

Conventional chemotherapies for cervical cancer, such as cisplatin (CDDP)-based treatments, are limited by high systemic toxicity and the development of cellular resistance. To address these drawbacks, this study reports the green synthesis of selenium nanoparticles (SeNPs) using Amphipterygium glaucum leaf extract (AGLE) and the development of a guar gum-based nanocomposite (SeNPs@GG) loaded with these NPs. The synthesized SeNPs showed a stable UV–Vis absorption band at 275 nm, a spherical morphology, and sizes ranging from 11 to 21 nm, as confirmed by TEM. FTIR and XPS analyses demonstrated interactions between Se and functional groups from the plant extract, indicating its dual role as a reducing and stabilizing agent. The guar gum nanocomposites (NCs) exhibited a porous structure with a homogeneous distribution of SeNPs, as evidenced by SEM and EDS. At the same time, XRD confirmed the crystalline nature of the SeNPs. In vitro cytotoxicity assays using HeLa cervical cancer cells revealed significant antiproliferative effects with a biphasic response related to Se’s dual biological role. The IC₅₀ values were 98.3 µg/mL for SeNPs, 93.7 µg/mL for SeNPs@GG1, and 93.5 µg/mL for SeNPs@GG2. Additional analyses confirmed apoptosis, DNA fragmentation, ROS production, mitochondrial dysfunction, and G2/M cell cycle arrest, supporting the potential of these systems as alternative chemotherapeutic strategies. Full article

During the machining processes, surfaces are often contaminated by cutting fluids, metallic debris, and residual films, which may compromise subsequent operations (e.g., coating, bonding, or precision assembly). In the present study, the effectiveness of several cleaning methods applied to machined metallic surfaces was experimentally evaluated. A set of commonly used industrial metals, including stainless steels, alloy steels, aluminum alloys, and brass, was machined under controlled conditions and subjected to various cleaning treatments, including solvent-based cleaning, ultrasonic washing, and aqueous detergent processes. Surface conditions were first assessed through optical microscopy, focusing on machining grooves as preferential sites for contaminant accumulation. Then, scanning electron microscopy (SEM) combined with energy dispersive X-ray spectroscopy (EDS) was employed to better identify residual contaminants. Optical observations highlighted the progressive removal of debris and lubricant residues, while SEM–EDS analyses revealed the presence of thin organic films and localized carbon-rich contaminants, even on apparently clean surfaces. Results show a consistent trend across all materials, with increasing cleaning effectiveness from solvent-based treatments to ultrasonic cleaning and specific aqueous detergent processes. Ultrasonic cleaning proved particularly effective in removing thin films and contaminants in complex geometries, whereas aqueous detergent treatment demonstrated superior performance in eliminating larger debris and achieving overall surface cleanliness. The findings, combining a broad experimental campaign across multiple materials, cleaning treatments, and characterization techniques, underline the importance of multi-scale characterization for a reliable assessment of cleaning efficiency and suggest that combined cleaning approaches may further enhance surface quality in demanding industrial applications. Full article

The sustainable utilization of multiple reclaimed pavement materials is a critical pathway toward green highway construction. This study investigates the performance and synergistic mechanisms of cold-recycled mixtures incorporating both Reclaimed Asphalt Pavement (RAP) and Reclaimed Cement-Stabilized Base (RCSB), using emulsified asphalt as the primary binder. A comprehensive experimental program was conducted to evaluate the effects of reclaimed material proportions, mixing sequences, and curing ages on the mechanical strength, moisture susceptibility, and high-temperature stability of the mixtures. Microscopic characterization via Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) were employed to elucidate the Interfacial Transition Zone (ITZ) evolution. Results indicate that an optimal RCSB incorporation range of 20–40% establishes a robust “stone-to-stone” rigid skeleton, significantly enhancing the splitting strength (up to 0.87 MPa) and durability (Splitting Strength Ratio, TSR > 91%). SEM observations confirm the formation of a dense interpenetrating network structure within this range, where cement hydration products and asphalt films achieve optimal chemo-physical bonding. Exceeding 40% RCSB leads to a moisture-starved state and a sharp decline in dynamic stability due to insufficient binder coating. Micro-morphological characterization reveals that the transition from macro-interfacial debonding to a robust cohesive failure mode is the fundamental driver for the performance peak at 20–40% RCSB. SEM observations confirm the formation of a dense interpenetrating network structure, where cement hydration products successfully anchor into the asphalt film. This optimized ITZ effectively eliminates the stress concentration and aggregate crushing seen in high-RAP mixtures, thereby ensuring superior mechanical integrity. Furthermore, a pre-wetting mixing sequence ensures a high-energy mineral surface that promotes the heterogeneous nucleation of cement. SEM results show that this prevents the competitive adsorption between cement and asphalt, transforming the ITZ from a friable, loose state into a densified crystalline adhesive matrix. Full article

According to the complementary advantages of the composites, the degradation rate, biological activity and physical and chemical properties of the composites were adjusted by using the hydrophilic and bioactive advantages of soy protein isolate (SPI) on the basis of toughening PLA by polycaprolactone (PCL). In this study, soy protein isolate/polylactic acid–polycaprolactone (SPI/PLA–PCL) composite microspheres were fabricated via double emulsion–solvent evaporation. SPI was introduced to regulate hydrophilicity, biodegradation, and bioactivity based on PCL–toughened PLA. The microspheres were characterized by SEM, EDS, FTIR, and XRD. Hydrophilicity, thermal stability, and degradation behavior were evaluated via water contact angle, TG/DTA, and in vitro degradation assays. Biocompatibility, hemocompatibility, and osteogenic activity were assessed through cell adhesion, hemolysis, CCK–8, ALP, alizarin red staining, and mineralization tests. Results confirmed the successful preparation of SPI/PLA–PCL microspheres. SPI incorporation enhanced hydrophilicity, degradation rate, and cell adhesion. The composite microspheres exhibited favorable thermal stability, hemocompatibility, biocompatibility, and osteogenic induction. The 50% SPI/PLA–PCL group performed optimally in cell proliferation, adhesion, ALP activity, and mineralization, demonstrating promising potential for bone tissue engineering applications. Full article

The electrolytic aluminum industry is facing severe challenges, such as excessive carbon consumption, resulting in more cost and environmental pollution due to the oxidation of carbon anodes. The isothermal oxidation resistance of B₄C-SiO₂-Albite (BSA) composite coating influenced by the in situ formation behavior and self-healing ability of the borosilicate glass at 1173 K was investigated through XRD, TG-DSC, Raman, FTIR spectroscopy, and SEM/EDS in this paper. The results show that the composite coating with 20 wt% B₄C has a relatively low mass gain rate of −0.082% after 24 h at 1173 K. It depends on the in situ formation of the amorphous borosilicate phase layer that can effectively protect the carbon anode from oxidation, which depends on the content of B₄C. The amorphous borosilicate glass forms from the reaction between the SiO₂ and the B₂O_3, from the oxidation of B₄C during exposure. More B₄C promotes the formation and volatilization of B₂O₃, which improves the viscosity and stability of the borosilicate glass by changing the glass network coupled with Na⁺ and Al³⁺ from Albite. It is a feasible strategy for designing durable coatings with appropriate B₄C addition for high-temperature applications. Full article

Trichloroethylene (TCE) is a pervasive groundwater contaminant, yet the practical application of nanoscale zero-valent iron (nZVI) is often limited by particle aggregation, rapid surface oxidation, and inefficient utilization of reactive electrons. Here, we developed a support–sulfidation coupled design to improve TCE dechlorination by integrating ZIF-8-enabled contaminant enrichment and dispersion with sulfidation-enabled surface-state regulation. A ZIF-8-supported sulfidated nZVI composite (ZIF-8@S-nZVI) was synthesized and systematically compared with nZVI, S-nZVI, and ZIF-8@nZVI. Among the tested materials, ZIF-8@S-nZVI exhibited the fastest TCE removal, the highest ethylene formation, and the highest chloride release, indicating the most effective dechlorination performance rather than merely adsorption-driven apparent removal. The optimal Fe:ZIF-8 mass ratio was 6:1. The composite also maintained high dechlorination capability over 20–40 °C, pH 6–9, and initial TCE concentrations of 10–40 mg/L, although 20 °C, near-neutral pH, and lower pollutant loading were kinetically more favorable. Multiscale characterization by FT-IR, N₂ adsorption–desorption and BET, XRD, EDS, SEM, and XPS indicated that ZIF-8 mitigated particle aggregation and retained partial pore accessibility, whereas sulfidation was associated with a more persistent Fe(II)-rich surface state after reaction. Together, these coupled effects promoted local TCE enrichment and sustained interfacial transformation. This study provides mechanistic insight and practical guidance for the rational design of MOF-supported sulfidated iron materials for chlorinated-solvent-contaminated groundwater remediation. Full article

In the cement-based stabilization of organic soil, the alkaline environment produced by cement hydration dissolves organic matter from the soil skeleton while simultaneously promoting the precipitation of neophases. This study investigates the coupled effects of structural deterioration and neophase compensation on the microstructural and mechanical properties of organic soil. Organic soil was treated with an alkaline Ca(OH)₂ solution (pH = 12.0) utilizing a model testing apparatus over an 80-day duration. Consolidation and permeability tests were combined with microstructural analyses (FTIR, XRD, and SEM-EDS) to elucidate the fundamental mechanisms. The results show that humus acid in organic soil was dissolved in an alkaline environment, significantly enlarging soil pores and forming interconnected dissolution channels. Consequently, the permeability coefficient and additional settlement increased by 49.21% and 18.07%, respectively, compared to the pristine soil samples. Concurrently, within the OH⁻-and Ca²⁺-rich environment, clay minerals underwent a pozzolanic reaction, generating C-(A)S-H gels. Dissolved humus acid formed complexes with Ca²⁺ ions. While these formed neophases provide microstructural compensation for the organic soil, their compensatory effect is limited. These findings provide a critical theoretical framework for understanding the coupled deterioration–compensation mechanisms, which is essential for optimizing engineering design and promoting the long-term durability of alkaline-reinforced organic geotechnical environments. Full article