Search Results (1,010)

Mycotoxins are fungal secondary metabolites with dual significance: they threaten health via food contamination yet hold potential as biopesticides. Their isolation from complex matrices remains a critical challenge. This review analyzes classical methods (liquid–liquid extraction, SPE including QuEChERS, chromatography). Traditional techniques suffer from poor selectivity, multi-step processing, large toxic solvent volumes, and matrix effects. As alternatives, emerging strategies based on rational design are considered: directed cocrystallization, supercritical fluid extraction, smart MOF/COF membranes, and AI integrated with physicochemical modeling. The concept of “precision” extraction enabling prediction of target isolation at the molecular level is developed. Recommendations for standardizing experimental reporting to create machine-readable datasets for neural networks are provided. The review concludes that while most still require experimental validation for mycotoxins, these approaches point toward selective, sustainable mycotoxin isolation technologies for analytical control and pure standard production. Full article

The increasing concentration of atmospheric CO₂ has intensified the urgent need for efficient and sustainable carbon capture technologies. Covalent organic frameworks (COFs) have emerged as a highly promising class of porous crystalline materials for CO₂ adsorption and separation owing to their structural tunability, high surface area, and precisely designable pore environments. This review summarizes recent advances in COF-based CO₂ capture systems, covering pristine COFs, functionalized frameworks, composite materials, and membrane-based architectures. In pristine COFs, CO₂ adsorption is mainly governed by micropore confinement and physisorption within well-defined channels, where surface area and pore size distribution play key roles. Functionalized COFs introduce additional active sites, including amine groups, heteroatoms, ionic functionalities, and alkali metal centers, which significantly enhance CO₂ affinity through stronger electrostatic and acid–base interactions, often leading to mixed physisorption–chemisorption behavior. Composite COFs and mixed-matrix membranes further improve performance through synergistic effects, interfacial engineering, and enhanced mass transport. Despite these advantages, challenges remain in achieving an optimal balance between capacity, selectivity, and regenerability under realistic conditions such as humidity, low CO₂ partial pressure, and multicomponent gas streams. Issues related to scalable synthesis, structural stability, and processability also limit practical applications. Overall, this review highlights key structure–property relationships and outlines future directions, including humid-stable COFs, direct air capture, computational design strategies, and advanced membrane technologies, for next-generation CO₂ capture materials. Full article

Friction at the drawbead in metal forming operations directly affects the quality of drawpieces. However, identifying the complex effect of friction process parameters on the coefficient of friction (CoF) is difficult based on experimental results. The aim of this paper is to analyze the results of a drawbead simulator test using various machine learning (ML) methods to select the most appropriate algorithm and to analyze in detail the feature importance, permutation importance, and cumulative Shapley additive explanation values of predictors. The test material was DC04 low-carbon steel sheet. Experimental tests were conducted for varying friction process conditions. Of the three different ML algorithms (support vector machine, regression trees, and ensemble tress), the support vector machine (SVM) algorithm with a cubic kernel function provided the lowest root mean square error (0.0085) and the highest correlation coefficient R² (0.9657) for the test data. The predictors in descending order of permutation importance are friction conditions, drawbead height, sample width, Sa of countersamples, and sample orientation. A combined swarm-box chart presenting Shapley values for an SVM model with a cubic kernel function indicates that a low value of the drawbead height predictor has a strong, increasing effect on CoF. However, low values of the remaining explanatory parameters (sample width, mean roughness of countersamples, and sample orientation) have a decreasing effect on CoF. Full article

Stenting is a minimally invasive treatment used in managing peripheral artery disease (PAD). However, clinical challenges persist, including in-stent thrombosis and restenosis, primarily driven by axial foreshortening or elongation and suboptimal balance between radial stiffness and flexibility inherent to conventional stent designs. This study proposes an innovative arrow-shaped geometry exhibiting zero Poisson’s ratio (ZPR) behaviour for 3D-printed self-expanding Nitinol stents. The complete stent deployment process was modelled using finite element analysis (FEA), including radial crimping and subsequent expansion to enable systematic parametric investigation while accounting for µ-3D printing constraints. Response surface methodology (RSM) rigorously evaluated mechanical performance, defining peak stress, chronic outward force (COF), radial resistive force (RRF), and foreshortening (FS) as constraint and objective functions within the optimisation framework. The optimised ZPR stent achieved favourable performance: extremely low foreshortening (|FS| ≤ 0.12%), representing outstanding axial stability compared with previously reported self-expanding stents, and a well-balanced radial response with ~50% higher radial strength than positive Poisson’s ratio (PPR) structures, while 16.67% lower than negative Poisson’s ratio (NPR) counterparts. These results highlight the ZPR stent’s capability to minimise axial deformation while maintaining adequate radial support, highlighting substantial potential for precise, stable deployment in PAD applications. Full article

Recent advancements in heterogeneous catalysis have increased the interest in the synthesis of metal-free polymer-based catalysts. This work presents a novel approach for the solvent- and additive-free synthesis of a nitrogen-rich catalyst. Our unique procedure yields a non-porous organic polymer (NPOP) with a wide range of functional groups on the surface, attributed to the incomplete polymerization inherent to our solvent-free method. Detailed analysis revealed significant differences between NPOP and its Covalent Organic Framework counterpart. Remarkably, the absence of a high surface area did not hinder the efficiency of NPOP as a catalyst for the CO₂ cycloaddition. The performance of NPOP exceeded that of its COF counterpart, with a conversion rate of 99% for NPOP and 35% for the COF. An observation attributed to the abundance of nitrogen functional groups on the surface of NPOP. A combination of characterizations and density functional theory (DFT) calculations was employed to thoroughly understand the working mechanism of NPOP. The imines and secondary amines on the surface function as the active sites for the ring-opening of epichlorohydrin. This study supports existing theories that N atoms can serve as nucleophiles by donating their free electron pairs. Furthermore, the distinctive synthesis procedure reported here can serve as inspiration for further design of polymer-based catalysts. Full article

The development of sustainable, noble-metal-free photocatalytic systems for acceptorless dehydrogenation (ADH) of cyclic amines remains a significant challenge. Herein, we report a novel heterogeneous photocatalyst constructed by covalently grafting a cobaloxime-based proton reduction catalyst onto a photosensitive covalent organic framework (PT-COF). The tailored PT-COF scaffold, featuring a donor–acceptor architecture and uncondensed amino groups, serves as both an efficient visible-light harvester and a porous support for cobalt active sites. The resulting Co-PT-COF hybrid exhibits excellent photocatalytic activity for the ADH of a wide range of cyclic amines, affording the corresponding N-heteroarenes in 62–95% yields under an Ar atmosphere at 28 °C with blue LED irradiation for 12 h in water. Notably, the catalyst demonstrates outstanding recyclability over five consecutive cycles with minimal loss of activity or cobalt leaching. Comprehensive photoelectrochemical and spectroscopic studies reveal that enhanced charge separation and efficient electron transfer from the photoexcited COF to the cobalt centers underpin the superior performance. Mechanistic investigations, including in situ EPR spectroscopy, confirm the involvement of α-amino radical intermediates in the catalytic cycle. This work establishes a sustainable platform for solar-driven dehydrogenation chemistry and provides a versatile blueprint for integrating molecular catalysts with photoactive frameworks. 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

Bismuth tungstate (Bi₂WO₆) is a typical bismuth-based visible-light-responsive semiconductor photocatalyst that has attracted significant attention in the fields of environment remediation and energy conversion. In this paper, to address the issues of high photogenerated carrier recombination rate and limited visible-light-response range of Bi₂WO₆, various modification strategies are highlighted, including morphology control, element doping, heterojunction construction, carbon material compositing, and coupling with functional materials such as metal–organic frameworks (MOFs), covalent organic frameworks (COFs), or conductive polymers. Furthermore, the structure–activity relationships are discussed. On this basis, the latest application progress of Bi₂WO₆-based photocatalysts in fields such as pollutant degradation, antibacterial activity, and energy conversion and storage is summarized. Finally, prospects are put forward regarding the existing shortcomings and future development directions in the application of Bi₂WO₆-based photocatalysts, aiming to provide a systematic theoretical reference for the design and application of high-performance Bi₂WO₆-based photocatalysts. Full article

Upcycling biomass waste into value-added battery materials is crucial for sustainable energy storage. Here, we transform coffee grounds into high-performance hard carbon (HC) anodes for sodium-ion batteries (SIBs) via a synergistic pre-oxidation and acetylene chemical vapor deposition (CVD) strategy, which effectively reduces open pores and promotes structural stabilization. The resulting material exhibits features consistent with a closed-pore architecture. Pre-oxidation incorporates oxygen-containing functional groups that template accessible pores and expand the interlayer spacing during carbonization. Subsequent CVD covers surface pores and contributes to the stabilization of the pore structure. The optimized HC (COF300&1300@C) exhibits a balanced set of structural features, including a low specific surface area (2.1 m² g⁻¹), expanded interlayer distance (0.391 nm), and a well-regulated pore system with reduced surface area and controlled pore size. As a result, it delivers a reversible capacity of 298 mAh g⁻¹ with an ICE of 70%, and remarkable cycling stability (97% capacity retention after 500 cycles at 1C). This study elucidates the synergistic mechanism of pre-oxidation and CVD in reducing open pores and stabilizing the pore architecture, thereby yielding characteristics indicative of closed-pore behavior, and providing a novel and efficient approach for designing high-performance biomass-derived hard carbons for energy storage. Full article

Background/Objectives: The rapid emergence of multidrug-resistant (MDR) bacteria has increased the demand for non-antibiotic antibacterial strategies. Although photothermal therapy (PTT) and photodynamic therapy (PDT) are promising alternatives, each modality alone may show limited antibacterial efficacy. This study aimed to construct a flexible dual-light-responsive nanofibrous membrane integrating PTT and PDT for improved in vitro antibacterial activity against MDR bacteria. Methods: A silica nanofibrous membrane (SNF) was prepared by electrospinning followed by calcination. An Fe-doped sulfonated TpPa covalent organic framework (SCOF-Fe) was then grown in situ on the SNF surface via an interfacial diffusion strategy to obtain SNF@SCOF-Fe. The membrane was characterized in terms of morphology, structure, optical absorption, photothermal performance, Fe loading, Fe leaching, and reactive oxygen species (ROS) generation. In vitro antibacterial activity against supplier-reported MDR Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA) was evaluated under 420 nm, 808 nm, and dual-light (420 + 808 nm) irradiation. Results: Fe doping broadened the optical absorption of the COF-functionalized membrane into the near-infrared region and improved its photothermal response. Under dual-light irradiation, SNF@SCOF-Fe generated singlet oxygen, superoxide radicals, and hydroxyl radicals, together with a greater temperature increase than the undoped membrane. Within 15 min, SNF@SCOF-Fe achieved antibacterial rates of 99.29% against E. coli and 99.62% against MRSA. In addition, controlled dual-light cytocompatibility testing yielded 78.76% viability in L929 fibroblasts and 82.86% viability in MC38 murine colon carcinoma cells after SNF@SCOF-Fe treatment. Conclusions: SNF@SCOF-Fe combines dual-light-triggered photothermal heating and ROS generation within a flexible nanofibrous membrane and demonstrated effective in vitro antibacterial activity against two representative resistant bacteria. These findings support further investigation of SNF@SCOF-Fe as a light-responsive antibacterial membrane in relevant in vitro and in vivo models. Full article

In pursuit of a composite coating for tunnel boring machine (TBM) disc cutters that offers both high wear resistance and self-lubricating functionality, we fabricated Fe-based composite coatings reinforced with WC and MoS₂ through laser cladding. Seven coating compositions with systematically tailored MoS₂ contents were prepared to investigate the concentration-dependent effects of MoS₂ on microstructural evolution and tribological properties, and to evaluate their performance under various rock-contact conditions. XPS results reveal that MoS₂ decomposed during laser cladding, leading to the in situ formation of metal sulfides in the Fe-based matrix. These sulfides, characterized by low shear strength, readily form a continuous and stable lubricating tribofilm at the hob–rock interface. The tribofilm effectively lowers the coefficient of friction (COF), curtails friction-induced energy dissipation and surface degradation, and ultimately enhances the wear resistance of the disc cutter. Simultaneously, the rapid non-equilibrium solidification inherent in laser cladding stabilizes metastable phases, which refine the microstructure, improve densification, and bolster phase stability. Among the tested compositions, the coating containing 4 wt.% MoS₂ exhibited the most favorable dry-sliding tribological performance, as evidenced by an average coefficient of friction of 0.409, a hardness of 749.5 HV1, and consistently low wear mass losses below 2.1 × 10⁻³ g under different rock-contact conditions. Mechanistically, XRD and SEM analyses further attributed the superior performance of the 4 wt.% MoS₂ coating to concurrent strengthening mechanisms: grain refinement, dispersion strengthening from uniformly distributed second-phase particles, and increased dislocation density. Collectively, these effects substantially improve the wear resistance of the disc cutter, thereby extending its durability and service life under complex operating conditions. Full article

To achieve accurate prediction of the surface COF (coefficient of friction) of titanium alloys under electrochemical corrosion conditions, this study investigates the tribological behavior of titanium alloys across various solutions, concentrations, voltages, and sliding velocities to construct a systematic dataset. Two machine learning models are developed and optimized: a standard Light Gradient Boosting Machine (LightGBM) and an enhanced LightGBM model incorporating lag and rolling features. These models are employed to predict the friction coefficient and feature importance analysis. The results indicate that solution concentration is the primary factor influencing the friction coefficient of the titanium alloy, followed by test duration, while sliding velocity exerts the least influence. Following experimental validation and iterative optimization, the enhanced LightGBM model, integrated with lag and rolling features, demonstrates superior predictive accuracy, achieving a coefficient of determination (R²) of 0.979 on the training set and 0.951 on the test set. This research establishes a data-driven predictive framework that demonstrates superior accuracy and interpretability compared to models using only raw features, showcasing the potential of feature-engineered machine learning in optimizing electrochemical machining parameters. Full article

Magnetic covalent organic frameworks (MCOFs) offer efficient adsorption via designable pore channels and active sites, along with rapid magnetic separation due to their intrinsic superparamagnetism. However, physical mixing or non-covalent assembly often leads to weak binding, causing the leaching or detachment of magnetic components during use, and compromises the well-defined crystallinity of the COF. In this study, we employed an in situ synthesis strategy at room temperature based on amidation and Schiff base reactions to fabricate a magnetic TAPT-DHTA-COF with good crystallinity and superparamagnetism. This material was used as a magnetic solid-phase extraction (MSPE) adsorbent to establish an MSPE-GC-MS/MS method for the determination of amide herbicides (AHs). The TAPT-DHTA-COF is rich in hydroxyl groups, which form strong hydrogen bonds with the polar AH molecules. In a green tea matrix, six AHs showed good linearity within the concentration range of 1–500 ng g⁻¹, with correlation coefficients ranging from 0.9910 to 0.9982. The limits of detection were between 0.25 and 0.73 ng g⁻¹, spiked recoveries ranged from 80.1% to 94.8%, and relative standard deviations were below 6.2%. This work offers an improved synthesis strategy for novel magnetic COFs and insights into their application in adsorbing polar pesticides. Full article

Silver-doped diamond-like carbon (Ag–DLC) coatings were investigated with respect to their tribological behavior under ambient and physiologically relevant conditions. Gradient Ag–DLC coatings deposited on AISI 316L stainless steel were tested in air, simulated body fluid (SBF), and an albumin-containing solution using a pin-on-disk configuration. Increasing silver content resulted in a systematic reduction in the H³/E² ratio, leading to increased coating wear irrespective of the environment. In contrast, friction behavior was strongly controlled by the surrounding medium. Under dry sliding in air, all coatings exhibited similar steady-state friction governed by the DLC matrix. The lowest steady-state friction coefficients were obtained in SBF, indicating that the aqueous ionic environment provided the most favorable friction conditions among the tested media. In the albumin-containing medium, friction also remained low, indicating that protein adsorption and interfacial layer formation modified the sliding conditions, although the CoF did not fall below that observed in SBF. Wear was highest in air and generally lowest in SBF, while tests in albumin promoted surface layer formation. Surface analyses indicated silver redistribution, transfer-layer formation, and the presence of protein-related surface agglomerates, with higher apparent surface coverage on coatings containing more Ag. Overall, the results show that Ag-doped DLC coatings exhibit environment-dependent tribological behavior under physiologically relevant conditions. The present work should be regarded as a tribological study rather than a direct validation of antibacterial performance. Future studies should combine tribological assessment with dedicated antibacterial and cytocompatibility experiments. Full article

The rapid increase in atmospheric ${\mathrm{CO}}_2$ concentration has made carbon capture an essential strategy for mitigating climate change. This review systematically summarizes ${\mathrm{CO}}_2$ capture technologies following the complete process chain. First, three major routes based on combustion stages are introduced: pre-combustion (e.g., coal gasification, biomass co-firing), combustion-based (oxy-fuel combustion and chemical looping combustion), and post-combustion capture. For post-combustion capture, which is the most widely applicable to existing emission sources, three core separation methods are further elaborated: absorption (amine blends, ionic liquids, deep eutectic solvents), adsorption (zeolites, activated carbon, MOFs, COFs, solid amine sorbents), and membrane separation (polymeric, inorganic, and mixed matrix membranes). Key strategies for performance enhancement—such as functionalization, pore engineering, and composite systems—are highlighted. Despite significant advances, large-scale deployment remains challenged by high costs, high energy consumption, and inadequate material stability. Future research should prioritize low-cost, energy-efficient, and robust capture materials and processes to enable net-zero and negative carbon emissions. Full article