Search Results (9,299)

Adsorption is a promising technology for phosphate removal to alleviate eutrophication. In this study, thermally modified calcium aluminate decahydrate (TCAH) was prepared via low-temperature thermal treatment of calcium aluminate decahydrate (CAH₁₀) to develop a cost-effective and high-performance phosphate adsorbent. The optimal modification temperature was determined to be 120 °C, which reduced the crystallinity of CAH₁₀, enhanced its porosity, and induced the formation of amorphous calcium aluminate phases. Batch adsorption experiments showed that TCAH exhibited a maximum adsorption capacity of 199.80 mg P/g at 25 °C. The adsorption kinetics followed the pseudo-second-order model, while the adsorption isotherms were well fitted by the Redlich–Peterson model. TCAH maintained high removal efficiency over a wide pH range of 3.0–11.0 and showed high selectivity against common coexisting anions. Characterizations using SEM-EDS, XRD, FTIR and XPS suggested that phosphate removal by TCAH was dominated by synergistic amorphous precipitation and inner-sphere complexation. In tests with real phosphorus-releasing liquor derived from excess sludge, TCAH achieved nearly complete phosphate removal at a dosage of 5 g/L within 6 h. Owing to its readily available raw materials, low preparation temperature, and outstanding phosphate capture performance, TCAH is a promising candidate for efficient phosphate capture and recovery from wastewater. Full article

The demand for sustainable, high-performance biomaterials has driven intense research towards natural polysaccharide hydrogels. Accordingly, this study aimed to synthesize novel starch-based hydrogel materials, considering their inherent hydrogel-forming capabilities together with diverse potential applications (e.g., pharmaceuticals, medicine, and the cleaning application for the artifacts). To obtain hydrogels with enhanced mechanical and physico-chemical properties, starch was combined with other polymeric species (i.e., alginate, polyvinyl alcohol, and polyvinylpyrrolidone), and a gelling process was induced by using calcium cations or borate anions. Two distinct hydrogels (named S-Ca and S-SB, respectively) were prepared and characterized by a range of instrumental and experimental techniques. The assessed properties included water and solvent resistance, equilibrium water content, water-releasing capacity, morphology and microstructural features with their composition by SEM-EDS analysis, and mechanical properties (tensile strength, elasticity, Young’s modulus, and hardness). The results indicated that the investigated hydrogels exhibited suitable properties for a variety of applications, including surface cleaning processes in the field of cultural heritage conservation. For instance, they showed equilibrium water content (between 80 and 90%) comparable with other hydrogels commonly used as cleaning tools (e.g., agar and p(HEMA)/PVP) and quite low water-releasing capacity (between 10 and 17 mgcm⁻²). Moreover, the S-SB hydrogel displayed distinctly better tensile strength and elongation at break than hydrogel prepared in the presence of Ca²⁺ (S-Ca). Notably, S-SB experienced considerable elasticity improvement after freezing–thawing cycles, as indicated by a decrease in tensile strength (from 275 to 102 kPa) and an increase in elongation at break (from 121 to 275%). However, it should be noted that the hydrogel selection depends on the requirements of the target application, as different processes demand materials with distinct characteristics. Hence, both S-Ca and S-SB hydrogels were tested as cleaning tools for the removal of artificially aged acrylic coating (i.e., Paraloid B-72) from the surface of marble and wood specimens, respectively. The tests provided positive results, as aged coating was satisfactorily removed by applying the hydrogels loaded with a nanostructured emulsion (NSE). These novel starch-based hydrogels demonstrate significant potential as high-performance alternatives to conventional hydrogel systems currently used in conservation science as well as in other industrial applications. Full article

Environmental pollution by polycyclic aromatic hydrocarbons (PAHs) is a serious environmental problem. One of the effective methods of cleaning the environment from these toxicants is the use of sorbents based on clay minerals. Special organo-mineral, bio-mineral and bio-organo-mineral complexes were obtained. Organo-mineral complexes (organoclays) were synthesized on the basis of Na-bentonite and anionic, amphoteric and nonionic surfactants. Bio-mineral and bio-organo-mineral complexes were produced by inoculating bentonite and organoclays with a consortium of bacteria. The adsorption characteristics of the complexes to benzopyrene and naphthalene were studied. Modification of bentonite with various types of surfactants leads to a significant increase in the percentage adsorption of both benzopyrene and naphthalene, with benzopyrene being more so. All bio-organo-mineral complexes adsorb more benzopyrene than pure bentonite and the bentonite + bacteria complex. In most cases, this pattern is also characteristic of naphthalene adsorption. Organoclay complexes with bacteria adsorb PAHs in greater quantities than organoclays, typically at the average concentrations of benzopyrene and naphthalene used (30–60 μg mL⁻¹) and when modified with individual surfactants. Based on the determination coefficients, the adsorption of benzopyrene and naphthalene by all studied sorbents is best described by the Langmuir equation. The maximum (limiting) adsorption of benzopyrene by all organo-mineral complexes (organoclays) exceeds the maximum adsorption of benzopyrene by bentonite. Modification of bentonite with surfactants may not change, decrease, or increase the maximum adsorption of naphthalene compared to the original bentonite, depending on the surfactant used. Colonization of the organoclay surface by bacteria, with rare exceptions, results in a decrease in the maximum adsorption values of benzopyrene and naphthalene compared to organoclay, or has no effect at all. Full article

Aqueous zinc–manganese dioxide (Zn–MnO₂) batteries are undergoing a paradigm shift from traditional ion-insertion mechanisms to a reversible deposition/dissolution process. By leveraging a two-electron transfer (Mn²⁺/MnO₂), this electrolytic system achieves a high theoretical capacity of 616 mAh g⁻¹ and a theoretical operating voltage of 1.99 V. However, the accumulation of dead Mn, electrically isolated inactive phases, and dynamic interfacial pH fluctuations remain critical barriers to cycle life and practical energy density. This review systematizes a trinitarian strategy to overcome these bottlenecks, focusing on interfacial engineering, redox mediator-assisted recovery, and advanced electrode architectures. We evaluate how anion engineering and pH-buffering stabilize reaction pathways, and how diverse mediators (e.g., halogens, metal ions, and organic molecules) chemically rescue inactive manganese. Furthermore, we examine the integration of 3D carbon networks and low-cost hybrid electrodes to sustain high-areal-capacity deposition. To elucidate these complex mechanisms, we highlight multiscale analytical approaches combining synchrotron X-ray techniques and density functional theory (DFT). Finally, we outline a roadmap for applications ranging from grid-scale flow batteries to flexible wearable electronics. This work provides a comprehensive perspective on realizing sustainable, safe, and high-performance zinc-based energy storage. Full article

Metanephrine (MN) and normetanephrine (NMN) are critical biomarkers for neuroendocrine tumors (pheochromocytoma and paraganglioma). Following our previous development of a molecularly imprinted solid-phase extraction (MISPE) sorbent for urine analysis, this study evaluated MISPE coupled with HILIC-MS/MS for determining metanephrines in human plasma. Unlike conventional phases, the novel polymer selectively binds analytes as in situ-generated anions via quaternary alkylammonium groups in hydroxide form, ensuring accurate extraction from just 25 µL of plasma. Validated per U.S. FDA guidelines, the assay showed good intra- and interday precision (CV < 10.8%), accuracy (bias < −10.6%) and excellent linearity (R² > 0.99) across pathological ranges (184.3–877.8 ng/L for MN; 174.8–923.0 ng/L for NMN), with low relative standard errors (<6.9%). Excellent selectivity was demonstrated in the presence of structurally close analogs (catecholamines, DOPA and its derivatives). Compared with commercial WCX, the sorbent yielded cleaner extracts, significantly reducing the phospholipid interference. Although lower limits of quantification (92.2 ng/L MN; 87.4 ng/L NMN) slightly exceeded healthy upper thresholds, the method has potential for use in specific clinical scenarios with pronounced biomarker elevations: diagnosis of pheochromocytoma/paraganglioma, monitoring post-treatment metanephrine decline, and tracking tumor-induced hypertensive crises in emergencies. This accessible protocol forms a solid foundation for advanced diagnostics. Full article

Tianjin, nestled on the North China Plain, possesses abundant geothermal resources with tremendous potential for development and utilization. This study employs hydrogeochemical and isotopic analysis techniques to thoroughly explore the geochemical characteristics and circulation patterns of geothermal fluids in Tianjin, shedding light on the mechanisms underlying the formation and evolution of deep geothermal fluids. The findings reveal that atmospheric precipitation serves as the primary recharge source for the region’s geothermal fluids, with the calculated recharge heights coinciding with those of the Jixian mountainous area. This precipitation infiltrates through permeable layers and the deep, large faults surrounding the southern plain, entering relatively enclosed or semi-enclosed geothermal reservoirs. As they circulate, the geothermal fluids undergo intricate interactions with the surrounding rocks, including processes such as leaching, adsorption, carbonate reprecipitation, cation exchange, and decarbonation. The fluids circulate at depths ranging from 1.6 to 3.5 km, with temperatures spanning from 67 to 133 °C. Along the flow path, the anionic composition of the geothermal fluids shifts from HCO₃⁻ dominance in the north to a coexistence of Cl⁻ and SO₄²⁻, ultimately dominated by Cl⁻ in the south, accompanied by an increase in total dissolved solids (TDS). The results indicate that Tianjin geothermal fluids are mainly recharged by meteoric water and evolve along their flow paths through dissolution of evaporitic and carbonate minerals, cation exchange, and carbonate precipitation. Hydrochemical and Sr-isotope differences suggest generally limited vertical connectivity among the studied reservoirs, although local hydraulic interaction may occur near conductive faults. These results provide constraints on the hydrogeochemical evolution and management of geothermal resources in the Tianjin sedimentary basin. Full article

This study examines a series of organic–inorganic crystal structures containing the periodate anion (IO₄⁻) to clarify the nature of the anion–anion interactions that are frequently referred to as halogen bonds. Our analysis demonstrates that, in many cases, IO₄⁻ does not develop an electrophilic σ-hole on the iodine center, even in the presence of organic cations, and therefore cannot reliably function as a halogen-bond donor. In its discrete (0D) form, the anion retains its character as a Lewis base. In crystal structures where extended architectures are observed—such as one-dimensional chains, two-dimensional layers, or three-dimensional cage-like assemblies—these structures arise predominantly from strong coulombic interactions with surrounding cations, as the interaction between the anions is intrinsically repulsive in the gas phase. Hydrogen bonding, together with other noncovalent interactions including chalcogen, tetrel, and/or pnictogen bonding, plays a dominant role in stabilizing the anionic arrangements and governing their structural organization. Full article

Ionic liquid-based localized high-concentration electrolytes, leveraging their intrinsically nonflammable safety characteristics and wide electrochemical windows, have emerged as strong contenders for next-generation lithium metal battery electrolytes. However, because such systems are anion-rich, the electrolyte bulk phase tends to form solvation structures dominated by bulky anionic clusters along with an excess of free anions, which triggers persistent and uncontrollable anion decomposition at the interphase. To address this issue, we adopt a strategy of constructing a compressed solvation structure by introducing a weakly interacting chlorinated diluent (TeCA), which helps form a compact solvation environment and alleviates excessive anion decomposition at electrode interphases. In this work, 1,1,2,2-tetrachloroethyl acetate (TeCA) was introduced as a weakly coordinating chlorinated diluent into an ionic-liquid localized high-concentration electrolyte (LHCE) to regulate the Li⁺-FSI⁻ solvation environment. By combining Raman spectroscopy, molecular dynamics simulations, and electrochemical characterization, the TeCA-LHCE system was found to exhibit altered ion-cluster configurations, improved oxidation tolerance, and enhanced interfacial stability under high-voltage conditions. The as-prepared TeCA-LHCE electrolyte presents improved electrochemical performance in comparison with TTE-LHCE and the baseline electrolyte (BE). The Li||Cu half-cell employing TeCA-LHCE achieved a high Coulombic efficiency above 99% over 500 cycles and formed a uniform and dense lithium deposition layer without obvious dendritic growth. When paired with a high-loading NCM811 cathode (10 mg cm⁻²), the TeCA-LHCE-based Li||NCM811 full cell delivered significantly improved cycling stability and rate capability under a high cutoff voltage of 4.3 V. Full article

The potency of urate, an abundant human plasma antioxidant, in preventing oxidative damage caused by the carbonate radical anion CO₃^•−, was studied using quantum chemical calculations. The influence of microhydration of CO₃^•−/CO₃²⁻ and urate⁻/urate^• couples on the thermodynamic and kinetics of the one-electron oxidation process was investigated. Depending on the degree of microhydration, the estimated rate constant for one-electron transfer is in the range of 2.0–7.3 × 10⁹ M⁻¹ s⁻¹, in good agreement with the experimental value of 1.3 × 10⁹ M⁻¹ s⁻¹. Modeling using vertical detachment energy and electron affinity, the driving forces of single electron transfer revealed urate(H₂O)₆⁻ and CO₃(H₂O)₉^•− clusters as the most likely existing species in water. Molecular docking revealed a favorable interaction of urate with the catalytic pocket of SOD1. Urate binds more strongly to the anionic active center of SOD1 than the reference inhibitor LSC-1, indicating its potency to prevent HCO₃⁻-supported CO₃^•− formation. In contrast, the known OGG1 inhibitor TH13264 shows substantially stronger binding than urate, indicating urate’s weaker affinity toward the DNA repair enzyme catalytic pocket. The molecular dynamics data indicate that urate binding does not destabilize either SOD1 or OGG1. In light of increasing evidence that the major source of oxidative stress could be CO₃^•−, rather than the commonly assumed hydroxyl radical HO^•, the obtained results indicate the inherent ability of plasma to combat oxidative stress induced by this selective, milder oxidant. Such an ability with respect to the non-selective, highly reactive HO^• does not exist in vivo. Full article

This study investigates the effect of hot-air drying temperature (45–70 °C) on the major bioactive constituents and in vitro antioxidant activity of artificially cultivated Sanghuangporus vaninii fruiting bodies. The contents of polyphenols and polysaccharides gradually rose with elevated temperature and peaked at 70 °C, whereas the flavonoid content reached the maximum at 55 °C and declined continuously afterwards. Among the tested bioactive substances, polyphenols exhibited the strongest antioxidant activity, with their DPPH and superoxide anion radical scavenging capacities peaking at 70 °C and hydroxyl radical scavenging capacity peaking at 55 °C. Correlation analysis revealed that the contents of polyphenol and polysaccharide possessed markedly positive correlations with DPPH and superoxide anion scavenging activities, yet no statistically relevant correlation was observed for flavonoids. Cluster analysis classified all tested temperatures into two clusters: low-temperature drying (45–50 °C) yielded inferior bioactive constituents and antioxidant activity, whereas medium-to-high-temperature drying (55–70 °C) delivered superior performance. From a practical perspective, drying at temperatures ≥55 °C is recommended to enhance product quality. Specifically, 70 °C is optimal to maximize overall antioxidant capacity, whereas 55 °C is preferable for flavonoid enrichment and color preservation. These findings provide an evidence-based strategy for the optimization of post-harvest drying processes of S. vaninii. Full article

Lead sulfide quantum dots (PbS QDs), as a functional-layer coating, enable non-volatile integration and neuromorphic computing in memristive structures to address the von Neumann bottleneck. Herein, the dual-interface mechanism of PbS QDs in the memristor film structure is reviewed. First, the local electric field enhancement effect generates tip electrode-like structures in the coating film through QD-mediated spatial charge gradients, thereby enabling precise control over the nucleation and growth of conductive filaments (CFs). As a result, the consistency of switching voltages and the thermal stability at elevated temperatures are significantly improved. Conversely, the anion reservoir effect exploits surface dangling bonds on QDs to efficiently capture anions from the dielectric layer, thereby synergistically regulating vacancy migration kinetics. This process enables zero-initialization behavior and ultra-low-power operation. In addition, the spatial distribution design and density modulation of QDs further reinforce both mechanisms. The structural optimization of QD/dielectric interface engineering can simultaneously improve cycling endurance and resistive switching uniformity. Furthermore, modification of QD surface chemistry through ligand decoration and passivation suppresses the stochasticity of ionic diffusion while improving the linearity of synaptic weight updates. This interfacial engineering strategy utilizing QDs as coating films advances the development of high-performance photonic–electronic systems for memory–computing convergence. Full article

Wastewater containing such inorganic contaminants, especially phosphate and nitrate ions, has to be treated thoroughly before disposal into natural environments. This is a precautionary measure to avoid adverse effects on public health, which are exacerbated when these two pollutants are present in an aqueous system. The present research investigated how the adsorption process is influenced by factors such as the effect of ion composition, contact time, temperature and competitive adsorption behavior in multi-anion systems using Ternary Biopolymer–Bentonite Beads. This study used five isotherms and four kinetic models to investigate phosphate ions removal on prepared natural Clay-Bio-polymer composite beads. The results indicate that the pseudo-second-order (PSO) kinetic model provides the most accurate description of the adsorption process. Moreover, the correlation coefficients (R²) obtained for both the Langmuir and Freundlich isotherm models are nearly equal to 1, confirming their strong reliability in fitting the experimental data. The strong fit of both the Langmuir and Freundlich models indicates that the adsorption process exhibits mixed behavior, with both monolayer adsorption on relatively homogeneous sites and multilayer adsorption on heterogeneous sites. This mixed-behavior system is typical of composite adsorbents with diverse surface properties. The Redlich-Peterson model, a hybrid of Langmuir and Freundlich, showed the best overall correlation (R² = 0.990 for H₂PO₄⁻ and 0.998 for NO₃⁻). The applicability of the Sips and Toth isotherm models, which account for both uniform and non-uniform adsorption behaviors, validated the experimental results. In the competitive binary system, the maximum adsorption capacities achieved by the composite were 121.844 mg/g for H₂PO₄⁻ and 27.979 mg/g for NO₃⁻. The results indicate strong competition between H₂PO₄⁻ and NO₃⁻ ions for the available active sites, reflecting an antagonistic adsorption. A positive value of ∆H° verifies that the adsorption process is endothermic and primarily physical, consistent with the experimental observations. The negative ∆G° values demonstrate that the adsorption occurs spontaneously, whereas the positive ∆S° indicates an increase in randomness at the solid–liquid interface during the uptake of phosphate ions. Full article

Pt-based catalysts remain the premier hydrogen evolution reaction (HER) electrocatalysts for anion-exchange membrane water electrolyzers. Faced with insufficient abundance and high cost, developing low-Pt electrocatalysts that can accelerate the Volmer step while maintaining high durability is critically important yet challenging. Herein, we propose niobium nitrides with excellent conductivity and stability as supports for Pt to enhance the alkaline HER. A polyoxoniobate-based molecular self-assembly strategy was ingeniously designed to fabricate Nb₄N₅ nanospheres, on which ultrafine Pt nanoparticles (NPs) were successfully immobilized, forming Pt/Nb₄N₅ heterostructures (denoted as Pt/Nb₄N₅). The rich interface structures with metal–support interactions drive charge transfer from Pt to Nb₄N₅, which modulates the electronic structure of Pt and Nb sites, collectively lowering interfacial charge transfer resistance, generating abundant active sites, and improving catalyst durability. Consequently, the Pt/Nb₄N₅ catalyst achieves exceptional HER performance, including a low overpotential (22 mV@10 mA cm⁻²), a small Tafel slope (26 mV dec⁻¹), an 11.5-fold higher mass activity at 150 mV, and remarkable durability, drastically surpassing the commercial Pt/C catalyst. Notably, the Pt/Nb₄N₅-based electrolyzer requires only 1.508 V to drive 10 mA cm⁻². This work offers a viable pathway to engineer highly active and durable low-Pt electrocatalysts for energy-related applications. Full article

Driven by the growing demand for functional textiles featuring excellent waterproofness, moisture permeability and mechanical robustness in outdoor sportswear, medical protection and technical apparel, traditional pongee—despite its desirable softness, high wrinkle resistance and good stability as an ideal substrate fabric—is severely restricted in further application by its intrinsically poor hydrostatic pressure resistance in extremely wet environments. Accordingly, we developed a modified waterborne polyurethane (WPU) coating for pongee substrates to fabricate functional textiles that maintain high hydrostatic pressure resistance while possessing good mechanical properties and increased UV absorption. In this study, by using the sol–gel method, an amorphous silicon dioxide (SiO₂) coating layer was constructed on the surface of titanium dioxide (TiO₂) particles, forming silica-modified titania particles (SiO₂/TiO₂). These SiO₂-modified particles were subsequently physically blended with an anionic waterborne polyurethane system that had been previously modified with a polyester-type modifier A to enhance its hydrostatic pressure resistance. The resulting composite coating was designed to combine the high hydrostatic pressure resistance inherited from the modified WPU matrix, the mechanical reinforcement and increased UV absorption contributed by SiO₂/TiO₂, and satisfactory water repellency on fabric substrates. The results indicate that the incorporation of an appropriate amount of modifier A into the prepolymer system significantly enhances hydrostatic pressure resistance while maintaining high elongation at break. At a SiO₂/TiO₂ loading of 0.2 wt%, the composite film exhibits optimal comprehensive performance, characterized by superior mechanical properties, low water absorption, and static water contact angles exceeding 100° for coated fabrics. SiO₂/TiO₂ composite WPU coatings substantially improve hydrostatic pressure resistance across various fabrics, with 380T polyester taffeta demonstrating the best performance. This resistance remains remarkably stable after standard washing, indicating excellent wash fastness and practical applicability. Full article

Background/Objectives: Cyclotides are plant-derived macrocyclic peptides distinguished by their head-to-tail cyclized backbone and cystine knot motif, which confer remarkable stability against thermal, enzymatic, and chemical degradation. These features, combined with a compact and rigid structure, position cyclotides as promising scaffolds for future antibacterial agents in response to the escalating threat of multidrug-resistant (MDR) pathogens and the stagnation of conventional antibiotic discovery pipelines. This review summarizes the structural features, antibacterial mechanisms, bioengineering strategies, and translational potential of cyclotides against MDR infections. Methods: A narrative review of the literature was conducted using recent original research articles and reviews on cyclotide structure, antibacterial activity, bioengineering, computational modeling, and pharmaceutical applications. Results: Cyclotides exhibit potent antimicrobial activity, primarily through membrane disruption mediated by amphipathic surfaces and affinity for anionic bacterial membranes. Some variants also demonstrate anti-virulence and antibiofilm properties, broadening their therapeutic relevance for difficult-to-treat infections. Bioengineering approaches, including epitope grafting and rational design, have improved selectivity and potency while reducing cytotoxicity. Advances in computational modeling, molecular dynamics, and artificial intelligence have accelerated the prediction and optimization of antimicrobial activity, toxicity, and pharmacokinetic properties. Conclusions: Innovations in synthesis, including recombinant expression and enzymatic ligation, are helping overcome translational barriers related to cost and scalability. Although challenges remain in oral bioavailability and systemic delivery, strategies such as lipidation and scaffold modification support the development of cyclotide-based therapeutics as adaptable platforms for peptide drug discovery. Full article