Search Results (906)

This industrial-scale study investigates cerium’s effect on inclusions, microstructure, and mechanical properties in Ti-bearing high-strength steel BT700L through comparative trials of two production batches (with/without 0.0035% Ce). Characterization via SEM/EDS, automatic inclusion analysis, and Factsage thermodynamic simulations revealed that Ce addition reduced spherical Al-Mg-Ca-O-S inclusions (from 24 to 7 per 2 mm²; size decreased from 17 μm to 10 μm) while promoting composite inclusions with AlCeO₃-Ca(Mn)S cores and Ce-containing Ti(C)N shells. Although square Ti(C)N inclusion numbers remained stable, their average size increased from 8 μm to 11 μm. Ce addition eliminated banded microstructure and refined grains through heterogeneous nucleation (Ce₂O₃ exhibits low misfit of 4.00% with α-Fe). Mechanically, yield strength increased marginally (<5%) with unchanged tensile strength and reducing elongation. However, −20 °C impact toughness decreased by 22%. This duality—beneficial grain refinement versus detrimental coarsening of angular TiN inclusions acting as stress concentrators—provides critical insights for optimizing Ce addition in industrial Ti-bearing high-strength steel BT700L. Full article

Bisphenol A (BPA) is a typical endocrine disruptor that poses a significant threat to ecosystems. Therefore, it is crucial to develop an efficient and environmentally friendly degradation technology. In this study, a novel bimetallic oxide-loaded GAC (Granulated Activated Carbon) particle electrode (CuFe₂O₄@GAC) was designed and applied to a three-dimensional electro-Fenton (3D-EF) system for efficient removal of BPA. The bimetallic synergistic effect of Cu and Fe was used to promote the Fenton reaction and enhance the efficiency of hydroxyl radical ·OH generation. The results show that under conditions of 20 g/L CuFe₂O₄@GAC, pH = 3, 10 mA/cm², and an electrode spacing of 2.0 cm, a BPA removal rate of over 93% (20 mg/L) was achieved within 45 min. The prepared CuFe₂O₄@GAC exhibits good stability, maintaining an 86.2% BPA degradation rate over five cycle experiments. The catalytic mechanism and degradation pathways were further analyzed through characterization methods such as radical quenching experiments, XPS analysis, EPR, and LC-MS detection. Radical quenching experiments confirmed that ·OH radicals play a significant role in the decomposition of BPA. Based on the identification of intermediates, a possible decomposition pathway for BPA was proposed. Toxicity analysis indicated that the toxicity of most intermediates was significantly lower than that of BPA. This work provides an efficient and energy-saving strategy for BPA removal. Full article

Corrosion of pipelines by flue gas desulfurization (FGD) wastewater compromises the normal operation of the desulfurization tower, and corrosion under high-chloride conditions in particular severely damages the tower’s internal structure. To further elucidate the corrosion mechanism at elevated Cl⁻ concentrations, the corrosion behavior of 20 steel exposed to high-chloride FGD wastewater at different Cl⁻ concentrations was investigated through weight-loss measurements, electrochemical tests, immersion corrosion experiments, composition analysis, and microscopic morphology characterization. The results revealed that higher Cl⁻ concentrations corresponded to lower corrosion rates: the corrosion rate reached 0.1964 mm/y in the absence of Cl⁻, but decreased to 0.1537 mm/y at a Cl⁻ concentration of 100,000 mg/L. XPS analysis showed that as the Cl⁻ concentration increased, the corrosion film gradually transformed from porous FeOOH into dense Fe₃O₄. Localized pitting analysis indicated a positive correlation between Cl⁻ concentration and pitting susceptibility. At Cl⁻ concentrations of 0 and 100,000 mg/L, the corrosion current density decreased from 32.44 μA/cm² to 6.43 μA/cm² after 72 h, decreasing by a factor of approximately 5.05. This behavior is attributed to the fact that Cl⁻ increases solution conductivity in high-chloride environments, thereby promoting the formation rate of the corrosion film. Additionally, high Cl⁻ levels reduce dissolved oxygen in the solution, causing the corrosion film to progressively react and form denser Fe₃O₄. Nevertheless, the high penetrability of Cl⁻ continues to aggravate pitting corrosion of 20 steel. Full article

This study systematically investigates the effect of solution treatment on the microstructure and corrosion resistance of duplex stainless steel SAF2507 fabricated by direct hot isostatic pressing (HIP). The HIP specimens were solution treated at 1080 °C for 1 h, followed by comprehensive characterization using SEM, EDS, EBSD, XRD, XPS, and electrochemical testing in 3.5 wt% NaCl solution. Results indicate that solution treatment effectively dissolved intermetallic precipitates, promoted a more uniform distribution of ferrite and austenite phases, and reduced microstructural heterogeneity. Electrochemical impedance spectroscopy and potentiodynamic polarization tests showed that the treated samples exhibited a wider passive region and higher charge transfer resistance, indicating enhanced passivation behavior. XPS analysis further revealed an increased proportion of Cr₂O₃ and O²⁻ and decreased ${\mathrm{Fe}}_{\mathrm{hy}}^{3+}$ and H₂O content in the passive film, suggesting improved compactness and chemical stability. Surface morphology analysis confirmed a significant reduction in pitting corrosion after treatment. These findings demonstrate that solution treatment is an effective post-processing method to enhance the corrosion resistance of HIP-fabricated SAF2507 duplex stainless steel. Full article

In this study, activated biochars derived from spent coffee grounds (CAC-600) and lemon pomace (LAC-600) were prepared through pyrolysis with FeCl₃ activation and evaluated for the selective adsorption of Acid Blue 74 (AB74), a dye widely used in the denim textile industry. FeCl₃ activation significantly increased the surface area and pore development relative to the pristine biochars, while also promoting the formation of Fe₂O₃ phases on the activated biochars surfaces. The activated biochars exhibited comparable adsorption capacities of 39.44 and 37.16 mg·g⁻¹ for CAC-600 and LAC-600, respectively, indicating that adsorption performance was governed mainly by the activation process rather than by the precursor biomass. Isotherm and kinetic models revealed heterogeneous adsorption behavior involving surface interactions combined with internal diffusion. The materials showed stable adsorption performance within a pH range of 4–10. Competitive adsorption experiments demonstrated preferential adsorption of AB74 over Acid Red 1 (AR1), confirming the selectivity of LAC-600 and CAC-600. Density Functional Theory (DFT) calculations revealed a cooperative adsorption mechanism combining π-surface interactions with localized Fe-oxide anchoring sites on the graphene-based model, increasing the adsorption energy by approximately 24 kcal·mol⁻¹ relative to carbon-only systems. These findings demonstrate the potential of Fe-activated agro-industrial biochars as adsorbents for dye removal from aqueous media. Full article

The objective of this study is to develop a nanosized, visible-light-responsive photocatalyst with magnetic separability and recyclability for repeated use. Spinel ferrite nanoparticles, which are environmentally friendly, are promising candidates for achieving this goal. Spinel ferrite nanoparticles were synthesized via a low-temperature hydrothermal method to investigate their microstructural characteristics, magnetic properties, and photocatalytic performance. Initially, four ternary spinel ferrite (MFe₂O₄, where M = Mg, Mn, Co, and Zn) nanoparticles were compared in terms of their physical properties and photodegradation efficiencies of organic dye methylene blue (MB). Among them, the MgFe₂O₄ and ZnFe₂O₄ samples exhibited superior photocatalytic activity compared to the MnFe₂O₄ and CoFe₂O₄ samples. Subsequently, a systematic investigation of the Zn–Mg ferrite system (Zn_1−xMg_xFe₂O₄, x = 0 to 0.8 in increments of 0.2) was carried out. The results revealed that the x = 0.8 samples achieved the highest photodegradation efficiency of 99 for a 10 MB aqueous solution under visible-light irradiation for 90 min. This improved performance is attributed to formation of a heterojunction of Zn–Mg nanoferrite/Fe₂O₃, which promotes light harvesting and prevents photogenerated charge recommendation, thus significantly improving photocatalytic activity. Full article

Bismuth oxide (Bi₂O₃) nanoparticles are attractive for biomedical and radiation-shielding technologies and can be further tailored through the addition of other metal oxides to address emerging needs such as antimicrobial resistance. This study investigated the effects of incorporating Fe₂O₃ and La₂O₃ on the structure, morphology, and antimicrobial performance of Bi₂O₃-based nanocomposites synthesized via a plant extract-assisted microwave–hydrothermal route using soapnut extract. XRD indicated that pure Bi₂O₃ (100B) comprised predominantly monoclinic α-Bi₂O₃ with coexisting metastable tetragonal β-Bi₂O₃. The addition of Fe (3F; Fe:Bi = 30:70) promoted β- Bi₂O₃ and formed BiFeO₃, while increasing La substitution (3L–20L) reduced the BiFeO₃ intensity and, beyond a threshold (≥7L), yielded distinct La₂O₃ peaks consistent with a La₂O₃–BiFeO₃–Bi₂O₃ composite. Crystallite size decreased from ~46 nm (100B) to ~25 nm (3F), varying with La between 33 and 25 nm. SEM/TEM revealed a reflection in morphology and size with composition from disk-like particles to petal-like spherical aggregates. Antimicrobial screening revealed composition-dependent inhibition: against S. aureus, 20L was the most potent (~94%). Overall, La/Fe tuning under a plant extract-assisted microwave–hydrothermal route enabled phase- and morphology-controlled Bi₂O₃-based nanocomposites with enhanced antimicrobial activity, with ultrafine, high-surface-area architectures emerging as promising antibacterial candidates. Full article

The electrochemical co-conversion of CO₂ and H₂O into valuable products is a promising approach toward carbon-neutral energy systems. Alloy exsolution from perovskite lattices has emerged as an effective strategy to engineer catalytic interfaces, yet the mechanistic influence of exsolved bimetallic species on CO₂/H₂O co-electrolysis remains insufficiently clarified. To address this gap, density functional theory (DFT) calculations were performed in this study to systematically examine how NiFe alloy clusters exsolved from the LSFNO (La_0.7Sr_0.3Fe_0.9Ni_0.1O_3-δ) (111) surface modify the electronic structure of the interfacial region and promote the RWGS reaction in CO₂/H₂O co-electrolysis. Our work highlights bimetallic alloy exsolution as a powerful strategy for improving co-electrolysis catalysts and offers valuable guidance for the rational design of next-generation high-entropy oxide systems. Full article

Due to the increased anthropogenic load, crops are polluted with heavy metals, including nickel (Ni). This is a serious environmental problem, as Ni penetrates barrier-free into cereal crops and accumulates in the grains used by humans and animals for food. Wheat is one of the main staple crops, cultivated in many countries. This study suggested that plant growth promoting bacteria (PGPB) with varying enzymatic activities could help wheat plants to cope with Ni stress by reducing Ni toxicity and regulating the metal’s homeostasis. PGPB Bacillus megaterium AFI1 has a strong phosphate-solubilizing activity and produces siderophores, while Paenibacillus nicotianae AFI2 has nitrogen-fixing and silicate-solubilizing activities. Both strains produce indole and polysaccharides and have 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. PGPB under Ni exposure (100 mg/kg of soil) significantly increased grain yield (by 34–42%) and decreased (by 20–33%) Ni content in wheat grains. PGPB also decreased malondialdehyde (MDA) and H₂O₂ levels in wheat plants under Ni stress. The contents of iron (Fe), boron (B), nitrogen (N) and phosphorus (P) decreased significantly and potassium (K) and zinc (Zn) oppositely increased significantly in all plant organs under Ni exposure. The inoculation with AFI1 mainly increased P and Fe, and the inoculation with AFI2 increased N and silica (Si) in wheat grains under Ni stress. In our experiments, under nickel exposure PGPB Bacillus megaterium AFI1 and Paenibacillus nicotianae AFI2 increased antioxidant protection of plants by decreasing the level of stress ethylene and regulating the homeostasis of nutrients in wheat plants. These PGPB can be considered as promising candidates for the development of biologicals to be used for growing plants in soils with low levels of nickel contamination. Full article

The accumulation of residual elements such as Cu and Sn in recycled steels has become an increasingly critical issue, as their enrichment during high-temperature oxidation can lead to surface hot shortness and deterioration of surface quality. In this work, the coupled enrichment behavior of Cu and Sn at the oxide/steel interface and its regulation by Si were systematically investigated through high-temperature oxidation experiments and microstructural characterization. The results reveal that selective oxidation of Fe during high-temperature exposure leads to the rejection of Cu toward the oxide/steel interface, resulting in significant interfacial enrichment. The presence of Sn further intensifies this enrichment by lowering the melting point of the Cu-rich phase and promoting the formation of Cu–Sn liquid films along grain boundaries, thereby aggravating intergranular penetration and surface degradation. In contrast, the addition of Si effectively suppresses the interfacial enrichment of Cu and Sn. Microstructural analyses indicate that Si promotes internal oxidation and facilitates the formation of Si-containing oxides such as Fe₂SiO₄ within the oxide scale and near the interface, which modifies the interfacial structure and limits the diffusion and accumulation of Cu-rich phases. Consequently, the formation and penetration of Cu–Sn liquid are significantly inhibited. These findings clarify the coupling mechanism of Cu and Sn during oxidation and reveal an effective Si-based strategy for mitigating the detrimental enrichment of residual elements in recycled steels, providing guidance for improving the surface quality of steels produced from scrap-containing charges. Full article

Perovskite-type oxides are among the most promising cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs) due to their mixed ionic–electronic conductivity and compositional flexibility. Many high-performance cathodes rely on Sr substitution at the A-site, often associated with surface segregation and long-term degradation. In this work, we explore an alternative strategy based on defect engineering and phase interactions in Sr-free composites. Perovskite-fluorite composites based on LaFe_0.8Co_0.2O₃ were synthesized through a one-pot route designed to promote the formation of a perovskite phase and a limited amount of fluorite-type ceria. This approach allows the introduction of small fractions of Ce into the perovskite lattice, favoring the cooperative coexistence with La-doped CeO₂. Structural, microstructural and spectroscopic characterization indicates that Ce influences the crystallization pathway and composite defect chemistry. Variations in lattice parameters and Raman features suggest modifications of perovskite structure consistent with defect formation and lattice distortion. Reduction properties and electrical conductivity measurements indicate that Ce incorporation in the perovskite and oxide interaction affect charge transport and oxygen mobility. The electrochemical results demonstrate that the optimal trade-off between activation energy (Ea) and polarization resistance (Rp) is achieved for the sample, with a nominal cerium content, Ce/(La + Ce) of 0.16. Moreover, the electrochemical properties are found to correlate with the nominal cerium content, which regulates defect chemistry and the resulting composite composition. Overall, results suggest that the one-pot synthesis promotes beneficial interactions between the perovskite and ceria phases, allowing the development of Sr-free ferrite-based materials with enhanced functional properties, minimizing the amount of ceria in the composite. Full article

Anaerobic digestion (AD) is an important method for sewage sludge (SS) stabilization and methane recovery. Fe compounds are widely present in SS because they are commonly used for phosphorus removal and organic matter (OM) capture in wastewater treatment plants. Endogenous Fe occurs in different forms, but the roles of these forms in SS AD remain unclear. This study systematically compared the effects of FeCl₃, Poly-FeCl₃, Fe₃O₄, FeOOH, and Fe₅HO₈·4H₂O on AD. The results showed that FeCl₃ and Poly-FeCl₃ decreased methane yield by 9.90% and 11.92%, respectively, whereas Fe₃O₄, FeOOH, and Fe₅HO₈·4H₂O increased it by 18.54%, 15.23%, and 15.09%. The analysis suggested that flocculating salts FeCl₃ and Poly-FeCl₃ groups increased sludge particle size, decreased SCOD concentrations by 10.21% and 12.41%, as well as F₄₂₀ by 16.88% and 28.63%, respectively, thereby inhibited the methanogenesis process. In contrast, Fe₃O₄, FeOOH, and Fe₅HO₈·4H₂O enhanced methane production by promoting OM hydrolysis, with SCOD concentrations increased by 12.71%, 8.99%, and 7.47%, respectively. XRD, CV, and EIS results showed that Fe₃O₄ likely promoted methanogenesis through a stable Fe(III)/Fe(II) cycle and electron transfer. Although FeOOH and Fe₅HO₈·4H₂O also underwent Fe(III)/Fe(II) conversion, their promoting effects were weaker than that of Fe₃O₄, possibly because the lack of a bulk mixed-valence structure reduced the efficiency of continuous electron transfer. This study highlights that the chemical form of Fe in SS fundamentally determines its effects on AD performance. Full article

The Dajing giant Cu–Sn polymetallic deposit is located in the Cu–Sn–Ag–Pb–Zn polymetallic belt of the southern Great Xing’an Range, NE China. Research on its ore genesis is of great significance for understanding Sn polymetallic mineralization in this region. In this study, pyrite, arsenopyrite, and sphalerite were analyzed by electron-microprobe analysis (EMPA) and in situ S–Pb isotope analysis. Previously published fluid-inclusion microthermometric and H–O isotope data were also incorporated to constrain fluid evolution and ore genesis. Both in situ S and Pb isotopic compositions fall within short ranges. The δ³⁴S values suggest a sulfur reservoir with possible magmatic contribution, whereas Pb isotopes indicate a mainly crustal Pb signature in an orogenic setting. Arsenopyrite records variations in As, S, Fe, and Co contents from core to rim. The Co-rich core shows Co enrichment accompanied by Fe depletion, consistent with Co-for-Fe isomorphous substitution. These features indicate changes in local fluid chemistry during arsenopyrite growth. Sulfur isotope geothermometry based on coexisting late-stage pyrite–sphalerite pairs yields 118–233 °C, with an average of 159 ± 49 °C, indicating medium- to low-temperature hydrothermal activity during the late sulfide stage. The Dajing deposit is interpreted as a fault-controlled hydrothermal vein-type Cu–Sn polymetallic deposit formed in a Late Jurassic extensional setting. Ore precipitation was likely promoted by cooling during upward fluid migration away from the magmatic heat source, pressure release, meteoric-water mixing, and fluid–rock interaction with granitic rocks and Linxi Formation wall rocks. This study provides mineral-scale constraints on fluid evolution and ore genesis in the Great Xing’an metallogenic belt. Full article

This study synthesized a novel Fe₃O₄/biochar composite (Fe₃O₄@BC) characterized by a porous structure and a high electron-donating capacity. The effect of Fe₃O₄@BC on ammonia emission and nitrogen loss during electric-field-assisted composting was investigated, and its underlying mechanism in nitrogen transformation was elucidated. Results demonstrated that the addition of an appropriate amount of Fe₃O₄@BC reduced cumulative NH₃ emission and total nitrogen loss by 30.00% and 4.03%, respectively. The favorable changes in gas emissions could be attributed to Fe₃O₄@BC-mediated modulation of key core microbial taxa. Under the electric-field-coupled condition, Fe₃O₄@BC addition significantly promoted the proliferation of Actinobacteria, such as Thermobifida and Corynebacterium, during the high-temperature phase, while concurrently suppressing the activity of Firmicutes. The shift in core microbial communities optimized key nitrogen transformation processes, including ammonification and nitrification, ultimately leading to reduced NH₃ emission. This study highlights the application potential of Fe₃O₄@BC in enhancing nitrogen retention and mitigating emissions during composting. Full article

Biocorona (BC) formation is a critical determinant of nanoparticle (NP) biological identity and downstream interactions, yet lipid association within BCs remains comparatively understudied relative to proteins, despite its potential relevance to NP stability, biodistribution, cellular interactions, and clearance. A more complete understanding of NP–lipid interactions is essential for optimizing NP-based therapies and supporting their safe clinical translation. In this study, we evaluated how serum concentration, biological sex, and NP size influence lipid association with iron oxide (Fe₃O₄) NP BCs. Lipids associated with 50 or 100 nm Fe₃O₄ NPs were characterized following incubation in male or female human serum across increasing serum concentrations of 5%, 10%, 25%, 50%, or 75% (v/v). Increasing serum concentration promoted greater lipid association and increased BC complexity, with higher serum conditions yielding more compositionally diverse lipid coronas. BCs formed on 50 nm Fe₃O₄ NPs consistently contained more lipid species than those formed on 100 nm Fe₃O₄ NPs, indicating pronounced size-dependent differences in lipid recruitment. BCs formed in male serum also contained more lipid species and a greater number of unique lipids than corresponding female BCs, demonstrating that biological sex significantly influenced both lipid composition and abundance within the BC. Rank-based comparisons further indicated that lipid association was governed not only by serum abundance but also by selective binding behaviors. Together, these findings demonstrate that lipid corona formation is strongly shaped by both the biofluid environment and NP design variables, emphasizing the importance of considering lipid coronas in NP design and evaluation, particularly for applications in drug delivery, nanomedicine, and precision diagnostics. Full article