Search Results (853)

In this work, three sulfur-iron materials (sulfide-modified nanoscale zerovalent iron (S-nZVI), ferrous sulfide (FeS), and pyrite (FeS₂)) were employed to enhance the Fenton process for naphthalene (NAP) degradation. The enhancement performance and mechanisms of S-nZVI, FeS, and FeS₂ were investigated and compared. The results showed that NAP removal was enhanced from 56.4% in the H₂O₂/Fe(II) system to 88.6%, 83.0%, and 89.1% with the addition of S-nZVI, FeS, and FeS₂, respectively. Three sulfur-iron materials could all reduce Fe(III) produced in aqueous solution, regenerate Fe(II), and slow down the precipitation of dissolved iron. In addition, the addition of sulfur-iron materials could promote the generation of hydroxyl radical (HO•), thus intensifying the degradation of NAP. The results of scavenging tests indicated that HO• was the dominant reactive oxygen species (ROS) for NAP removal, while superoxide radical (O₂⁻•) also participated. The effect of complex water matrices on NAP degradation was evaluated, showing that sulfur-iron material-enhanced techniques had a wide pH application range and had great tolerance to inorganic ions and humic acid. Moreover, NAP degradation intermediates and their toxicity were elucidated. Finally, the obvious removal of various pollutants in sulfur-iron material-enhanced systems demonstrated that these technologies could be used to remediate organic-polluted groundwater. Full article

The influence of zirconia incorporation and template type on the physicochemical properties of NiMo/Al₂O₃-ZrO₂ catalysts was investigated for the hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and the hydrogenation (HYD) of naphthalene (N). Catalysts were prepared by co-impregnation on supports synthesized via a sol-gel method using starch (A) and activated carbon (C) as structure-directing templates, followed by zirconium incorporation through a grafting procedure. The resulting materials were characterized by SEM–EDX, N₂ physisorption, H₂-TPR, XPS, HRTEM, and pyridine-FTIR. SEM-EDX confirmed homogeneous metal distributions and compositions close to nominal values (Mo = 20 wt%, Ni = 5 wt%, Zr = 11 wt%) with Ni/(Ni + Mo) = 0.30. N₂ adsorption–desorption isotherms correspond to type IV(a) with H3-H4 hysteresis loops, characteristic of mesoporous structures. After metal incorporation, surface areas decreased to 96 m² g⁻¹ for NiMo/Al₂O₃ and 81 m² g⁻¹ for Zr-modified catalysts, while the activated carbon-templated sample preserved a larger mesoporous volume (0.335 cm³ g⁻¹) and higher macroporosity (72%). H₂-TPR profiles indicated improved reducibility for Zr-containing catalysts. XPS revealed an increase of MoS₂ species from 45% in NiMo/Al₂O₃ to 75% in NiMo/Al₂O₃-ZrO₂(C), accompanied by a higher degree of sulfidation index (DSI) from 47.1% to 73.9%. HRTEM analysis of Zr-modified catalysts revealed longer MoS₂ slabs (11.8–12.1 nm) and higher edge-to-corner ratios (17–17.4) compared with NiMo/Al₂O₃ (6.2 nm; fe/fc = 8.2). Pyridine-FTIR showed a substantial increase in total acidity from 91 to 421 μmol g⁻¹ upon Zr addition. Catalytically, NiMo/Al₂O₃-ZrO₂(C) exhibited the highest HDS conversion (40%), reaction rate (10.5 × 10⁻⁹ mol s⁻¹ g⁻¹), and TOF (4.69 × 10⁻⁵ s⁻¹), whereas NiMo/Al₂O₃-ZrO₂(A) reached the highest naphthalene conversion (97.18%), with a reaction rate of 27.4 × 10⁻⁷ mol s⁻¹ g⁻¹ and TOF of 12.9 × 10⁻³ s⁻¹. These results demonstrate that Zr incorporation and the activated carbon template favored hydrodesulfurization, whereas the starch template promoted hydrogenation performance. Full article

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

This study investigated the biosynthesis of magnetite nanoparticles mediated by chia mucilage (CM-Fe₃O₄ NPs) and their application in the co-encapsulation of Lactobacillus rhamnosus GG (LGG) using spray drying. CM-Fe₃O₄ NPs were synthesized by combining CM extract with iron salts, in which hydroxyl and carbonyl groups of CM acted as natural ligands for Fe²⁺/Fe³⁺ ions. A response surface design was applied to optimize synthesis parameters, focusing on size distribution and zeta potential, and confirming the influence of pH on colloidal stability. Characterization by FE-SEM, DLS, XRD, UV-Vis, and FTIR revealed spherical particles with an inorganic core (50–300 nm) and a hydrated organic coating (600–900 nm), consistent with a spinel structure functionalized by CM. Spray-drying encapsulation tests showed that incorporating CM-Fe₃O₄ NPs did not compromise bacterial viability, maintaining optimal moisture content and survival. Growth curves and confocal microscopy corroborated the physiological compatibility of the nanoparticles, with no alterations in LGG morphology or growth dynamics. Under simulated gastrointestinal conditions, co-encapsulated microcapsules exhibited slightly improved survival in the gastric phase and significantly greater viability in the initial intestinal phase. These results suggest that CM-Fe₃O₄ NPs modulate matrix degradation and promote controlled release, ensuring therapeutic concentrations of LGG in the intestine. Overall, the CM-Fe₃O₄ nanocomposite system integrates the protective properties of biopolymers with the functional advantages of iron nanoparticles, offering dual functionality: probiotic stabilization and potential iron supplementation. This innovative, food-grade approach supports the development of next-generation functional foods with combined therapeutic and nutritional benefits. Full article

Iron oxide nanoparticles have emerged as multifunctional compounds with prominent potential in cancer theranostics, particularly in photothermal therapy (PTT) and photodynamic therapy (PDT). Their unique electronic and crystal structures, such as the dispersion of Fe²⁺ and Fe³⁺ ions and d-orbital splitting, contribute to their magnetic and catalytic properties. In PTT, Fe₃O₄ nanoparticles exhibit moderate near-infrared (NIR) absorption and photothermal conversion efficiency, which can be enhanced through adjustments in particle size, surface modification, and combinations with other components. In PDT, Fe₃O₄ nanoparticles demonstrate intrinsic peroxidase-like catalytic activity, facilitating Fenton and photo-Fenton reactions that generate reactive oxygen species (ROS), including hydroxyl radicals (^•OH), thereby amplifying oxidative stress in cancer cells. These nanoparticles can also function as carriers for photosensitisers (PS), promoting targeted delivery and enhanced ROS generation. Multifunctional nanomaterials that integrate Fe₃O₄ with other therapeutic agents and targeting ligands have demonstrated synergistic antitumour effects through amplified photothermal, photodynamic, chemodynamic, and chemotherapeutic mechanisms. Despite certain drawbacks, such as relatively low NIR absorption and challenges in optimising delivery and light activation, ongoing improvements in Fe₃O₄-based nanoplatforms present significant potential for enhancing treatment outcomes and the precision of cancer therapy. This article systematically explores the synergistic role of Fe₃O₄ nanoparticles in PTT and PDT, encompassing their magnetic and catalytic characteristics. Additionally, it focuses on multifunctional hybrid nanoplatforms that combine Fe₃O₄ with targeting or imaging agents, highlighting their potential to enhance therapeutic precision. Full article

Achieving selective conversion of lignin-derived phenolic compounds to cycloalkanes under mild conditions remains a significant challenge. Herein, we report a novel iron-incorporated two-dimensional NiO nanosheet supported Pd-Pt alloy catalyst (Pd_1.7-Pt_0.3/NiO-5FeO_x) that is capable of facilitating highly efficient hydrodeoxygenation (HDO) of lignin-derived phenolic model compounds (e.g., 2,6-dimethoxy-4-methylphenol) under mild conditions (250 °C, 5 atm H₂). The reaction mechanism was investigated through various characterization techniques and mechanistic studies: introducing FeO_x into the NiO support increases the proportion of defect-related oxygen species (Oβ), enhances adsorption of the key hydrogenated alcohol intermediate 4-methylcyclohexanol, and optimizes the acidity distribution of the catalyst, thereby promoting C(_sp³)-O bond cleavage (dehydroxylation) toward cycloalkane formation. The catalyst achieved high conversion (>95%) for various lignin-derived phenolics and high selectivity (93.0%) toward methylcyclohexane under mild conditions. This work offers new insights into the design of efficient biomass conversion catalysts under mild conditions and provides an energy-efficient route for the sustainable utilization of lignin resources. Full article

Photo-Fenton technology is considered an effective method for removing organic pollutants from water. In this work, a novel Mn-doped FeWO₄ (Mn-FeWO₄) photocatalyst was synthesized via a one-step hydrothermal method and applied for the photo-Fenton degradation of tetracycline (TC). The optimal Mn-FeWO₄-0.05 achieved 100% removal of TC within 60 min under visible light irradiation with a degradation rate constant of 0.0793 min⁻¹, which is 4.5 times higher than that of pristine FeWO₄. Systematic characterization revealed that Mn²⁺ ions were successfully incorporated into the FeWO₄ lattice, inducing lattice expansion and narrowing the bandgap from 2.37 eV to 2.25 eV, while also adjusting the conduction and valence band positions. This modulation significantly enhanced visible light absorption and promoted the separation and migration of photogenerated electron–hole pairs. In addition, the Mn²⁺/Mn³⁺ and Fe²⁺/Fe³⁺ dual redox cycles ensure the continuous generation of reactive oxygen species. Radical trapping experiments and electron paramagnetic resonance (EPR) spectroscopy demonstrated that superoxide radicals (•O₂⁻) and photogenerated holes (h⁺) were the dominant reactive species, while singlet oxygen (¹O₂) and hydroxyl radicals (•OH) played auxiliary roles. Moreover, Mn-FeWO₄-0.05 exhibited excellent stability, strong anti-interference ability against common anions, and high degradation efficiency toward various pollutants. Full article

(1) Background: Overuse of chemical nitrogen fertilizers drives the need for biological alternatives. Azotobacter chroococcum is a promising free-living nitrogen-fixing bacterium, but its efficiency needs improvement. This study investigated how Fe₃O₄ nanoparticles (Fe₃O₄ NPs) and molybdenum trioxide nanoparticles (n-MoO₃) affect A. chroococcum growth and nitrogen fixation, and tested the modified inoculants on Glycine max (legume) and Nicotiana benthamiana (non-legume); (2) Methods: In vitro tests measured bacterial growth, viable counts (CFU), nitrogenase activity, and nitrogen metabolites (total N, NO₃⁻-N, NH₄⁺-N) under 0–100 ng·mL⁻¹ Fe₃O₄ NPs or n-MoO₃. Pot experiments then tested modified inoculants on Glycine max and N. benthamiana for biomass and N, P, K uptake; (3) Results: Both nanomaterials showed low-dose stimulation and high-dose inhibition. At 10 ng·mL⁻¹, bacterial growth (OD₆₀₀ up ~1.2×) and nitrogenase activity (up >90%) rose significantly (p < 0.05–0.001), along with higher total N, NO₃⁻-N, and NH₄⁺-N. In pots, 10 ng·mL⁻¹ modified inoculant improved all Glycine max traits and nutrient uptake (p < 0.05). For N. benthamiana, biomass peaked at 20 ng·mL⁻¹, while stem and root growth did best at 10 ng·mL⁻¹. At 100 ng·mL⁻¹, effects weakened or vanished. A “metabolic remodeling–rhizosphere transformation–systemic response” mechanism is proposed; (4) Conclusions: Low concentrations (10–20 ng·mL⁻¹) of Fe₃O₄ NPs and n-MoO₃ can effectively boost the nitrogen-fixing function and growth-promoting effect of A. chroococcum inoculant, showing good potential for use on both legume and non-legume crops. This study provides a theoretical basis and technical reference for developing efficient, broad-spectrum nanomaterial-microbe composite inoculants. Full article

Radiation-induced bone injury, characterized by oxidative stress damage and impaired osteogenesis, lacks effective treatments. Exosome-based therapies have recently emerged as a safe and effective modality for radiation damage, and their functional capacity can be further potentiated through tailored preconditioning strategies—such as nanoparticle induction or physical stimulation. This study developed a novel exosome-based therapy by preconditioning bone marrow mesenchymal stem cells (BMSCs) with Iron oxide (Fe₃O₄) magnetic nanoparticles (MNPs, 50 µg/mL) and a static magnetic field (SMF, 100 mT). Exosomes derived from these preconditioned cells (BMSC-Fe₃O₄-SMF-Exos) exhibited enhanced yield and dual functionality. In irradiated BMSCs, BMSC-Fe₃O₄-SMF-Exos significantly promoted osteogenic differentiation, restoring alkaline phosphatase activity, mineralization, and expression of RUNX2, OCN, and COL1A1. They concurrently alleviated oxidative stress by scavenging reactive oxygen species, reducing malondialdehyde, and boosting superoxide dismutase activity. Mechanistically, miR-429 was found to be highly enriched in BMSC-Fe₃O₄-SMF-Exos, which directly targeted Noggin (NOG). Our functional validation experiments also confirmed that overexpression of miR-429 could inhibit NOG, alleviate oxidative stress and rescue the osteogenic differentiation of irradiated BMSCs. In conclusion, exosomes derived from preconditioning BMSCs with Fe₃O₄ MNPs and SMF mitigate radiation-induced damage via the miR-429/NOG pathway, presenting a promising cell-free strategy for bone regeneration. Full article

Fenton-based processes are widely used advanced oxidation methods that are known for degrading persistent pollutants. However, these techniques often generate significant amounts of iron-containing sludge, which poses environmental disposal challenges due to its complex composition. Furthermore, the sludge produced by the Fenton process contains a high content of Fe(III) compounds, which can serve as an iron source to stimulate dissimilatory iron reduction (DIR), enhancing the performance of anaerobic digestion. Based on the characterization results from a previous study, this work investigated the use of the ferrous precipitate generated by the electrochemical peroxidation process applied to tannery wastewater treatment as an additive to enhance volatile fatty acids (VFAs) production during dark fermentation. The performance of ferrous precipitate (R-Fe₃O₄) was compared to that of conventional magnetite (Fe₃O₄) during dark fermentation under high organic loading conditions, emphasizing their potential to enhance hydrolysis efficiency and VFAs production yields, while promoting sustainable resource recovery and reuse within a circular bioeconomy framework. The results showed that the addition of both Fe₃O₄ and R-Fe₃O₄ significantly increased the VFAs yields, with a predominance of long-chain fatty acids. The presence of CaCO₃ in the ferrous precipitate contributed to maintaining a stable pH environment, supporting microbial activity and enhancing the hydrolysis of soluble compounds. Moreover, the availability of essential micronutrients within the ferrous precipitate favored greater microbial diversity. Consequently, the addition of R-Fe₃O₄ promoted VFAs production, even at higher organic loading rates, suggesting a promising application of Fenton-based by-products as functional additives to improve the economic and environmental performance of the dark fermentation process. Full article

Flexible piezoelectric materials demonstrate broad application potential in wearable health monitoring, human–machine interaction, and biosensing. However, the piezoelectric response of pure PVDF-TrFE is limited and insufficient to meet the requirements for highly sensitive sensing. In this study, ZnO/PVDF-TrFE composite films with varying ZnO doping contents (3–11 wt%) were fabricated and systematically characterized in terms of their structural, thermal, and electrical properties. The results indicate that ZnO significantly promotes the formation of the polar β-phase in PVDF-TrFE, with the maximum β-phase content (F_β = 24.76%) and optimal piezoelectric performance achieved at 9 wt% ZnO doping. Devices based on this optimal composition exhibited stable ultrasonic transmission and reception capabilities under high-frequency pulse excitation, enabling sensitive detection of minor static pressure variations (e.g., contact pressure) through changes in ultrasonic echo signals, thereby realizing wearable conformity monitoring. Moreover, a sensor designed with a three-channel flexible substrate successfully captured human wrist pulse signals with high accuracy, demonstrating the practical utility and reliability of the device in flexible bio-electronic sensing applications. Full article

Developing stable alumina-based scales is critical for alumina-forming austenitic (AFA) alloys exposed to highly basic molten carbonates. However, the inherently sluggish diffusion of Al in austenite often limits the establishment of continuous protective layers. Herein, a thermomechanical treatment (TMT) strategy is proposed to enhance short-circuit diffusion pathways and promote selective Al oxidation in a Li–Na–K carbonate melt at 700 °C. After 90% cold rolling, annealing at 800 °C and 1000 °C generated two distinct microstructural states characterized by different grain boundary types, dislocation densities, and NiAl precipitate populations. The 800 °C-annealed alloy exhibits a significantly lower steady-state corrosion rate (~62 μm/yr) compared with the coarse-grained 1000 °C counterpart. EBSD and TEM analyses reveal that ultrafine grains, abundant low-angle boundaries, and finely dispersed NiAl precipitates provide efficient fast-diffusion channels and local Al reservoirs, enabling rapid formation of a continuous LiAlO₂/Al₂O₃ inner layer. In contrast, insufficient Al flux in the 1000 °C microstructure results in extensive internal oxidation and growth of a thick, non-protective LiFeO₂/NiO scale. These findings demonstrate that controlling the defect and grain-boundary structure via TMT is an effective route to overcome Al diffusion limitations and improve the molten-carbonate corrosion resistance of AFA alloys. Full article

The corrosion behavior and mechanism of Q235 steel during a two-year exposure to the subtropical marine atmospheric environment on an offshore platform in the East China Sea were investigated in this study. Methods including corrosion weight loss measurement, macro/micro-morphological observation (using a digital camera, SEM, and 3D-CLSM), composition analysis (XRD and XPS), and electrochemical tests (EIS and Tafel polarization curves) were employed to systematically examine corrosion kinetics, rust layer evolution, and electrochemical performance. The results indicated that the corrosion rate of Q235 steel initially increased and subsequently decreased with prolonged exposure, with the atmospheric corrosivity reaching CX level as defined (according to the ISO 9223 standard). The corrosion products transitioned from an early-stage rust layer predominantly consisting of γ-FeOOH to a later-stage layer primarily composed of α-FeOOH and Fe₃O₄. XPS analyses revealed that both the α*/γ* ratio and the Fe(II)/Fe(III) ratio increased over time, demonstrating a progressive improvement in the protective properties of the rust layer. The polarization resistance of the rust layer gradually rose, while the corrosion current density declined significantly, further confirming the enhanced stability and protective performance of the rust layer following long-term exposure. Chloride ions accumulated at defects within the rust layer, inducing local acidification, which played a key role in promoting the initiation and propagation of pitting corrosion. This study elucidated the corrosion behavior and mechanism of Q235 steel in the marine atmospheric environment of the East China Sea. Despite the increase in exposure time from 6 to 24 months, during which the electrochemical stability of the rust layer enhanced over time, it failed to prevent the initiation and propagation of severe localized corrosion—an issue of critical importance for load-bearing structures. The findings provide important theoretical and data support for service-life assessment and corrosion protection design of offshore photovoltaic steel structures. Full article

The bioconversion of propionate, a well-known intermediate of anaerobic digestion (AD), to methane is energetically unfavorable under standard conditions, which typically occurs in the syntrophy of bacteria and methanogens via methylmalonyl-CoA (MMC) and the dismutation pathway. Since the latter, which is reported only in Smithella, possessed a thermodynamic advantage over the former, enriching Smithella and promoting the syntrophic interaction and metabolism of the microbiota are important for improving AD efficiency. In this study, lysine-modified Fe₃O₄ (Lys@Fe₃O₄) significantly enhanced the bioconversion of propionate to methane. The methane yield and the maximum methane production rate (R_max) in a Lys@Fe₃O₄ reactor were 278.7% and 271.7% of Blank, and the corresponding values were 201.9% and 201.6% of bare Fe₃O₄, respectively. The metaproteomic results indicated that Lys@Fe₃O₄ increased not only the abundance of Smithella but also the expression of cell surface and adhesion proteins, thereby promoting syntrophic interaction between Smithella and methanogens and facilitating electron and acetate transfer from Smithella to methanogens. Moreover, the expression of quorum-sensing proteins was enhanced, benefiting the cooperation of Smithella and its associated bacterium (Syntrophomonas). Furthermore, the expressions of key enzymes related to metabolism and electron transfer in propionate oxidation, butyrate oxidation, CO₂-reductive methanogenesis and acetoclastic methanogenesis were all significantly upregulated. The results are of great significance for maintaining low propionate concentration and stability of AD. Full article

The recycling of spent lithium iron phosphate (LiFePO₄, LFP) batteries is receiving increasing attention as electric-vehicle deployment accelerates worldwide. Pyrometallurgical reduction offers a viable route for large-scale recovery of iron-rich products from spent LFP batteries; however, the resulting Fe-based alloys often retain residual copper (Cu), which deteriorates alloy quality and constrains downstream utilization and refining. In this study, a sulfidation–slag refining process was developed to selectively remove Cu from an Fe–P–Cu alloy produced by dry reduction of spent LFP batteries. FeS was employed as a sulfidizing agent to promote preferential conversion of Cu into sulfide phases, while fayalite (Fe₂SiO₄) slag was introduced to enhance phase separation between metallic and sulfide/slag phases. Thermodynamic calculations coupled with high-temperature experiments were conducted at 1400–1600 °C under various Cu:FeS ratios to identify operating conditions that maximize Cu removal while minimizing Fe loss. The results indicate that Cu is selectively transferred from the metallic phase to Cu–Fe–S sulfide phases, whereas Fe remains predominantly in the metal phase. Under the optimal condition (1400 °C, Cu:FeS = 2:1), the refined metal reached an Fe content of 90.80 wt.%, achieving an Fe recovery of 87.42% and a Cu removal efficiency of 81.13%. The proposed approach provides a practical stepwise refining strategy for upgrading Fe-rich secondary resources recovered from spent LFP batteries and facilitates subsequent impurity-control processes. Full article