Search Results (2,201)

Tailings are solid waste generated during mining and mineral processing. Their tremendous accumulation not only encroaches on arable land but also pollutes the environment. Currently, tailings are considered a viable alternative to natural fine aggregates in concrete because of their suitable physicochemical properties. However, existing studies remain highly fragmented and often report inconsistent conclusions owing to the considerable variability in tailings mineralogy, particle morphology, and physicochemical characteristics. To date, a comprehensive synthesis linking these intrinsic properties to the fresh, mechanical, durable, microstructural, environmental, and economic performance of tailings concrete remains lacking. Therefore, this review provides a systematic and critical assessment of tailings as aggregate in concrete and proposes an integrated framework connecting tailings characteristics, microstructural evolution, engineering performance, and sustainability outcomes. It systematically examines the physico-mechanical properties, durability, microstructure, hydration characteristics, environmental impact, and economic benefits of the resulting tailings concrete. The results showed that although tailings varied considerably in particle size, chemical composition, and mineralogy, they typically exhibited a rough surface texture and high water absorption. Furthermore, partial substitution of fine aggregates with tailings was found to improve the physical–mechanical properties and durability. However, to prevent performance decline, the substitution ratio should not exceed 50%. These benefits originated primarily from the filling effect and optimized particle packing, which increased matrix density. Microstructural analyses indicated that moderate tailings contents refined the pore structure, strengthened the interfacial transition zone (ITZ), and promoted hydration. In contrast, excessive substitution ratios weakened bonding and increased porosity. From an environmental perspective, the use of tailings generally reduced carbon emissions (by up to ~28%) and production costs (by up to ~50%) by lowering natural resource consumption and enabling large-scale waste valorization. Overall, tailings represent a sustainable aggregate alternative, provided that substitution levels are carefully controlled to balance workability, performance, and durability. Full article

An emerging environmental pollutant, microplastics have garnered global attention due to their widespread presence in soil and aquatic ecosystems. Early research primarily treated microplastics as single pollutants, focusing on their individual toxic effects. However, microplastics in the environment exist as a complex mixture, comprising various polymer types, sizes, shapes, and aging states. This diversity influences how microplastics regulate ecosystem carbon and nitrogen cycles and intervene through pathways such as direct carbon input, physical disturbance, microbial community restructuring, and coupled effects. This paper systematically reviews the characteristics of microplastic diversity and its mechanisms influencing carbon and nitrogen cycles: the chemical structure of polymers determines bioavailability and degradation rate, with biodegradable plastics altering carbon and nitrogen transformations more significantly than conventional plastics; microplastics of different sizes affect nitrogen transformation dynamics by modulating specific surface area and microbial colonization, with small-sized biodegradable microplastics particularly inhibiting plant nitrogen uptake; aging modifies surface properties and dissolved organic carbon release, thereby enhancing their role in promoting greenhouse gas emissions. Existing studies are largely confined to short-term laboratory simulations, leaving a gap in understanding the comprehensive effects of microplastic diversity under long-term, field conditions. Future research should focus on standardized methods and long-term experiments with multi-factor coupling to provide a scientific basis for ecological risk assessment of microplastic pollution. Full article

Sustainable water remediation requires catalytic strategies that remove contaminants efficiently while reducing chemical input, byproduct formation, and ecological disturbance. Conventional radical-dominated advanced oxidation processes can rapidly degrade pollutants, but their reliance on high oxidant dosages and freely diffusing reactive oxygen species often causes matrix quenching, non-selective oxidation, low oxidant utilization, and potential ecological risks. Mild interfacial catalysis provides a materials-chemistry strategy to regulate oxidative intensity and direct contaminant transformation under environmentally relevant conditions. In this review, mild catalysts are defined by pathway-selective, interfacially confined, and environmentally compatible oxidation rather than by low dosage alone. Representative non-radical or low-intensity pathways, including singlet oxygen generation, surface-mediated electron transfer, high-valent metal–oxo species, and direct oxidative transfer processes, are discussed in relation to active-site structure, oxidant utilization, matrix tolerance, and byproduct control. We further summarize how coordination environments, defect chemistry, heteroatom configurations, nanoconfinement, and immobilized interfaces regulate reactive-species formation and interfacial charge transfer. Key material platforms, including single-atom catalysts, heteroatom-doped carbons, defect-engineered oxides, catalytic membranes, hydrogels, and floating or immobilized composites, are evaluated from mechanistic and application-oriented perspectives. Finally, catalyst regeneration, cost, microbial community responses, algae–bacteria balance, ecotoxicity, and long-term safety are discussed to guide sustainable aquatic ecosystem restoration. Full article

Per- and polyfluoroalkyl substances (PFAS) are a group of anthropogenically manufactured chemicals widely detected in the environment. Characterizing their transport and fate in soil is important for assessing the potential of their human exposure and health impact. However, to date, few studies have been conducted to investigate the influence of PFAS on soil physical properties. This study investigates the impact of PFAS exposure on the surface wettability of soil via contact angle (θ) measurements. Contact angle was measured based on the fluid uptake rate in the Washburn capillary rise (WCR) method. Contact angles were measurably affected by the presence of 0.5 µg/g PFAS, with an increase of 4.5–6.8% for the exposed Accusand 40/50 and a decrease of 3.6–16% for the exposed Eustis soil, after 7 days of contact. The changes were attributed to the modification of the surface properties caused by the adsorbed PFAS. These results demonstrate that PFAS can potentially alter the surface properties of soils, which could subsequently impact soil hydraulic properties as well as affect geochemical interactions. Full article

This study evaluated the retention force between milled polyetheretherketone (PEEK) posts with different surface treatments and resin composites for core build-up, and the effect of thermal cycling on the retention force. Four groups of PEEK posts were prepared: untreated group (NT), mechanically treated group with sandblasting (SB), chemically treated group with primer application (AD), and a group combining mechanical and chemical treatments (SB+AD). Pull-out tests were conducted on these groups. The specimens were divided into two subgroups: one stored in a humid environment at 37 °C for one week (TC0) and the other subjected to 10,000 cycles of thermal cycling between 5 °C and 55 °C (TC10,000). Data were analyzed using two-way ANOVA and Tukey’s test. Additionally, the effect of thermal cycling on each group was examined using Student’s t-test. Both surface treatment and thermal cycling factors had statistically significant effects on retention force (p < 0.05). The interaction between these factors was also statistically significant (p < 0.05). The results showed that the retention force of the treated groups was significantly improved compared to the untreated group, with the SB+AD group exhibiting the highest retention force, followed by the SB group and then the AD group. Thermal cycling did not affect the retention force in the NT, SB, and SB+AD groups. These findings suggest that the combination of mechanical and chemical surface treatments is the most effective method for improving the retention force between PEEK posts and resin composites for core build-up. Furthermore, appropriate surface treatment of PEEK posts may influence their long-term durability. Full article

High-entropy alloy (HEA) coatings exhibit enhanced chemical stability when doped with carbon, primarily due to the strong bonding between carbon and transition metals. Typical transition metals used in these coatings include Cr, Fe, Co, Ni, Cu, Ti, V, W, Nb, Ta, and Zr. Owing to their excellent chemical stability, HEA coatings are widely employed to protect component surfaces operating in highly corrosive environments. Against this backdrop, the present study investigates the effect of carbon doping introduced via methane gas flow during the physical vapor deposition of TiAlTaZrNb HEA coatings on corrosion resistance. The morphology and structure of the coatings were analyzed by field emission scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. Corrosion protection and coating resistance were assessed through potentiodynamic polarization and electrochemical impedance spectroscopy. While increasing the methane flow resulted in an approximately 34% reduction in coating thickness, the overall coating resistance increased by one order of magnitude, reaching a maximum at a methane flow rate of 9 sccm, corresponding to the carbon solubility limit. This improvement was evidenced by a decrease in the corrosion rate from 8.02 × 10⁻² mm y⁻¹ for the uncoated H13 steel to 8.00 × 10⁻⁴ mm y⁻¹ for the HEA-coated samples. However, at higher methane flow rates, carbon precipitation and the formation of parallel microcracks contributed to an increase in corrosion rate. Full article

Mo–Re alloys serve as critical structural components for high-temperature nuclear reactors, and their irradiation degradation is closely related to the evolution of vacancy-type defects. In this study, heavy-ion and He-ion irradiations were performed under RT to introduce an average displacement damage of 3.5 dpa within the 1 μm-thick surface layer of Mo–Re alloys with Re content up to 47 wt.%. PALS, SPB-DBS and CDB techniques were employed to characterize the size, concentration, depth distribution and local chemical environment of irradiation-induced vacancy-type defects. The results demonstrate that the longer lifetime component of irradiated Mo–Re alloys ranged from 262 to 280 ps, corresponding to medium-sized vacancy clusters. The S parameter of all specimens increased significantly from approximately 0.42 to 0.50, with negligible differences (<0.01) among various Mo–Re alloys. No distinct characteristic peak of Re was observed near 17 × 10⁻³ m₀c at the vacancy sites, which was inconsistent with simulation predictions. Mo–Re alloys exhibit similar vacancy-type defect features to pure Mo, implying weak interactions between Re solute atoms and vacancy-type defects under RT irradiation. Full article

Modern cell imaging is increasingly evolving toward high-content, label-free, and spectrally rich analytical approaches capable of resolving biochemical heterogeneity at cellular and subcellular levels. Raman microspectroscopy (µRS) and surface-enhanced Raman scattering (SERS) provide molecularly specific vibrational fingerprints with minimal photobleaching and high multiplexing capability, making them attractive tools for biomedical imaging and cellular analysis. However, broader implementation remains limited by weak intrinsic signals, insufficient targeting specificity, and limited control over nanoscale sensing environments in complex biological systems. Metal–organic framework (MOF) nanoparticles have recently emerged as promising platforms to address these challenges by offering porous, chemically tunable, and structurally well-defined scaffolds for Raman- and SERS-active nanostructures. Their high stability and favourable biocompatibility further support integration into biological applications. This review summarizes recent advances in MOF-assisted µRS and SERS across chemical sensing, bioanalytical detection, and biomedical diagnostics, with particular emphasis on cellular and subcellular imaging. Unlike previous reviews focused primarily on sensing performance, this work highlights the emerging role of MOF-SERS systems in high-content cellular imaging and evaluates their translation toward biologically relevant environments. Key design strategies and current challenges are critically discussed. Full article

Activated carbon is a commonly used catalyst and catalyst support. Its abundant surface groups play a key role in catalytic activity and selectivity, and therefore an in-depth investigation of the surface groups of activated carbon is of great significance. The surface groups of activated carbon are diverse and structurally complex, and the corresponding characterization methods are also varied, with each technique having its own advantages and limitations. This review systematically summarizes the sources, characteristics, and effects on catalytic processes of oxygen-containing, nitrogen-containing, phosphorus-containing, and other heteroatom-containing groups on activated carbon surfaces. Emphasis is placed on the application of Boehm titration, PZC/IEP, FT-IR, XPS, TPD-MS, Raman, XRD, solid-state NMR, SEM/EDS, and EPR/ESR in the study of surface groups on activated carbon. Because the formation and alteration of surface groups on activated carbon not only change the surface chemical properties of activated carbon but also affect its structure, charge, and related properties, a single characterization method cannot accurately and comprehensively reveal its characteristics. Therefore, in practical studies, multiple characterization methods should be combined for cross-validation from the perspectives of functional group type, chemical state, thermal stability, structural changes, and catalytic behavior, so as to establish reliable correlations among “group type–structural environment–catalytic performance” and provide a basis for the rational design and optimization of activated carbon catalysts. Full article

Lithium-metal batteries (LMBs) are considered among the most promising high-performance energy storage systems because lithium metal possesses extremely high theoretical capacity and the lowest electrochemical potential among anode materials. However, their practical implementation remains severely limited by several critical challenges at the nanoscale, including uncontrolled lithium dendrite growth, unstable solid-electrolyte interphase formation, low Coulombic Efficiency, and large volume fluctuations during repeated lithium plating and stripping processes. In recent years, nanostructured porous framework materials have emerged as effective host structures and interfacial regulators for stabilizing lithium metal anodes due to their high surface areas, tunable pore architectures, and functionalizable chemical environments. In this review, we systematically summarize the recent progress in metal–organic frameworks (MOFs), covalent organic frameworks (COFs), covalent organic polymers (COPs) and other organic framework materials for lithium-metal anode applications. First, the fundamental working principles of LMBs and the major challenges associated with lithium metal anodes are discussed. Subsequently, the structural characteristics and advantages of MOFs, COFs, COPs and other framework materials are compared, followed by a detailed discussion of lithium storage mechanisms in porous frameworks, including lithium adsorption and nucleation, regulation of plating and stripping, dendrite suppression, and stabilization of the solid electrolyte interphase. Key design strategies, including hierarchical pore engineering, lithiophilic chemical functionalization, and electronic conductivity enhancement, are systematically highlighted. Representative advances in COF-based, MOF-based, and COP-based materials for lithium metal stabilization are critically summarized and compared. Finally, the remaining challenges and future research directions for porous framework materials in LMBs are discussed. This review aims to provide fundamental insights and design strategies for the rational development of advanced porous framework materials toward safe, stable, and high-energy LMBs. Full article

Foraminiferal shell crystals incorporate the chemical signals of their environment during growth. The recorded information is extracted from the crystals via proxies and can be used to reconstruct paleoenvironments, paleoclimates, and the change of the latter. However, the information that is obtained from the biocrystals is often biased, due to structural and chemical modification of the crystals resulting from dissolution, precipitation, recrystallization, and overall, the transformation of the biologically formed crystals into their inorganic analogs. Electron-backscatter diffraction (EBSD) measurements and analysis render a wide range of information regarding crystallographic-structural attributes of the crystals, such as crystal-microstructure, crystal-texture, the misorientation interrelation of adjacent crystals, crystal-twin-generation and many more. We demonstrate in this study that diagenetic overprint of foraminiferal shell Ca-carbonate crystals can be identified by structural-crystallographic characteristics obtained from EBSD measurements. We investigated modern/pristine and fossil Trilobatus sacculifer shells and observed an undisturbed shell surface for both. Despite the latter, we demonstrate here that with an increase in the degree of fossilization and diagenetic overprint, there is an increase in recrystallized calcite in the shells and a decrease in twinned calcite. Twinned calcite is the hallmark of pristine T. sacculifer shells. We show that, with increasing degrees of shell overprint, crystal-microstructure, and crystal-texture, the frequency of the 60°|<001> twin misorientation is modified and propose to use structural-crystallographic attributes determined with EBSD measurements for the identification of recrystallized/overprinted foraminiferal carbonate. We discuss that disclosing low degrees of overprint is of main importance, as minor structure changes of overprinted shells are easily overlooked with SEM imaging. Nonetheless, these are readily identified with EBSD-measurements. Full article

Metal–organic frameworks (MOFs) are crystalline porous materials made of metal nodes coordinated by organic linkers. Their high surface areas, tunable pore sizes, adjustable chemical environments, and modular design make MOFs promising for two main application domains: environmental remediation and energy conversion or storage. In this review, we explore the applications of both newly designed MOFs and MOF-derived materials. These applications include catalysis, electrocatalysis, sensing, pollutant removal, batteries, supercapacitors, and other hybrid energy devices. We attempt to correlate MOF structure with key parameters, such as metal centers, ligands, defects, and porosity, to performance. We also discuss the future use of MOFs in real-world devices. This depends on overcoming challenges such as scalability, conductivity, stability, and environmental safety. Full article

This investigation primarily focuses on addressing the challenges posed by the traditional use of carbon steel, which, despite its strength and cost-effectiveness, is prone to rapid corrosion in harsh chemical environments within the petrochemical industry. This issue constitutes a chronic operational vulnerability, exacerbated by extreme environmental stressors. The combined effect of corrosive atmospheres and rigorous EHSS (Environment, Health, Safety, and Security) mandates creates a significant fiscal burden, primarily driven by escalated lifecycle maintenance and the necessity for specialized regulatory compliance. Integrating Inconel, known for its exceptional corrosion resistance and durability, particularly at high temperatures, will significantly enhance the lifespan, safety, and operational efficiency of these vessels. This investigation aims to study the corrosion resistance of carbon steel specimens and carbon steel specimens clad with Inconel at thicknesses of 2 mm and 4 mm in different environments: acidic pH = 2 (HCl), neutral pH = 7 (distilled water), and alkaline pH = 12 (NaClO). All specimens were tested at the same immersion intervals of 5 and 10 days. Corrosion resistance was measured for the immersion corrosion tests. Weight loss in the specimens was measured before and after immersion to calculate the corrosion rate, and surface analysis was conducted using a scanning electron microscope (SEM). It was observed that at pH = 12 (NaClO), carbon steel corrosion reached a rate of 6.96 mm/year, while Inconel showed very low corrosion, 0.05 mm/year, indicating a resistance 139 times greater than that of carbon steel. At pH = 2 (HCl), carbon steel corrosion reached a rate of 1.29 mm/year, while Inconel showed a very low corrosion rate of 0.015 mm/year, indicating a resistance 86 times greater than that of carbon steel. In a neutral environment, all materials exhibited approximately the same corrosion rate between 0.0017 and 0.12 mm/year. This indicates that Inconel is highly resistant to corrosion in both acidic and alkaline environments, making it suitable for petrochemical plants. Full article

It is well-known that high-performance thermal protective clothing is crucial for personnel working in high-temperature environments, such as firefighters. Thermal protective clothing design usually integrates textile materials’ type, thickness, physical and chemical properties (such as thermal conductivity), ergonomics, and environmental adaptability. In this study, the heat transfer process and the optimal thickness are mainly discussed for providing some references on the design of this clothing. The thickness design of thermal protective clothing fabrics is carried out via numerical heat transfer simulations based on experimental data obtained from manikin tests. Firstly, one heat transfer model for thermal protective clothing, including three textile materials’ layers and one air layer, is constructed according to Fourier’s law of heat conduction, Newton’s law of cooling, and the Stefan–Boltzmann law, with appropriate boundary conditions assigned. Secondly, the finite volume element method, which has the important advantage of preserving conservation properties for physical quantities, is employed to discretize the heat transfer model. Thirdly, the convective heat transfer coefficient, which characterizes heat exchange between fluid and solid surfaces, is determined approximately by the least-squares method based on the given data, while the heat transfer process is simultaneously simulated. Fourthly, the thicknesses of the second and fourth layers are critical to the performance of thermal protective clothing. Two optimization algorithms are proposed to determine the optimal thickness configuration that effectively balances thermal insulation and wearing comfort. From the above results, it is recommended to use multilayer textile composite materials incorporating aerogel insulation layers and phase-change material interlayers. Full article

Biogenically synthesized metal-based nanoparticles have emerged as an attractive alternative to traditional physicochemical methods. The conventional way to prepare metal nanoparticles involves using toxic chemicals as reducing agents and stabilizers, which is tedious to handle and highly detrimental to the environment. Hence, biological synthetic routes for the biosynthesis of metal nanoparticles have been widely explored in recent research. It involves using biological molecules present in organisms, such as bacteria, plants, and fungi, as well as vitamins and enzymes, to reduce, stabilize, and regulate nanoparticle growth. These green-synthesized nanoparticles have demonstrated promising biomedical applications, especially as antibacterial, anticancer, anti-inflammatory, and neuroprotective agents, owing to their superior biocompatibility and surface chemistry. In addition, there is potential to develop therapeutic formulations that leverage the interactions between nanoparticles’ properties and biological systems. This review discusses the mechanisms of biogenic synthetic routes, with a detailed discussion of plant, bacterial, enzymatic, fungal, and vitamin-mediated green synthetic metal-based nanoparticles and their applications in biomedical and drug delivery fields. Full article