Search Results (236)

Constructing two-dimensional (2D) novel materials using superatoms as building blocks is currently a highly promising research field. In this study, by employing an oxidation strategy and based on first-principles calculations, we successfully predicted two types of 2D borides, namely B₁₂X₂H₆ (X=O, S), with icosahedral B₁₂ serving as their core structural unit. Ab initio molecular dynamics simulations demonstrated that these two borides exhibit exceptionally high structural stability, retaining their original structural characteristics even under extreme temperature conditions as high as 2200 K. Electronic structure calculations revealed that B₁₂O₂H₆ and B₁₂S₂H₆ are both wide-bandgap indirect semiconductors, with bandgap widths reaching 4.92 eV and 5.25 eV, respectively. Analysis via deformation potential theory showed that the phonon-limited carrier mobilities of B₁₂X₂H₆ can reach up to 1469 cm²V⁻¹s⁻¹ (for B₁₂O₂H₆) and 635 cm²V⁻¹s⁻¹ (for B₁₂S₂H₆). Notably, the surfaces of B₁₂X₂H₆ demonstrate excellent migration performance for alkali metal ions, with migration barriers as low as 0.15 eV (for B₁₂O₂H₆) and 0.033 eV (for B₁₂S₂H₆). This study not only expands the family of 2D materials based on B₁₂ superatoms but also provides a solid theoretical foundation for the potential application of B₁₂X₂H₆ in the field of low-dimensional materials. Full article

This study investigates all-solid-state batteries employing multifunctional metallic current collectors/electrodes that remain electrochemically inert toward an alkali-based Na ion solid electrolyte. Inconel 625 was evaluated as the positive current collector in combination with aluminum as the negative electrode and the ferroelectric electrolyte Na2.99Ba0.005OCl. The inertness of both electrodes enabled the construction of a robust device architecture that behaved as a true battery, exhibiting a two-phase equilibrium discharge plateau at ~1.1 V despite the absence of traditional Faradaic reactions. After a one-month rest period, the cell was sequentially discharged through external resistors and retained full functionality for one year. Cyclic voltammetry confirmed a stable electrochemical response over repeated cycling. The final long-term discharge under a 9.47 kΩ load produced a steady ~0.92 V plateau and delivered a total capacity of 35 mAh (~2.3 mAh·cm⁻²). Post-mortem analyses revealed excellent chemical and mechanical stability of Inconel 625 after extended operation, while aluminum showed superficial surface degradation attributed to residual moisture, with X-ray diffraction indicating the formation of aluminum hydroxide. Scanning Kelvin probe measurements guided electrode selection and provided insight into interfacial energetics, whereas scanning electron microscopy confirmed interface integrity. Complementary density functional theory simulations optimized the crystalline bulk and surfaces of Inconel, demonstrating interfacial stability at the atomic scale. Overall, this work elucidates the fundamental driving forces underlying traditional battery operation by studying a “capacity-less” system, highlighting the central role of interfacial electrostatics in sustaining battery-like discharge behavior in the absence of redox-active electrodes. Full article

The continuous solid solution series based on the ion exchangeable Dion-Jacobson layered perovskites, A_1−xA′_xLaNb₂O₇ (A/A′ = Li, Na, K, Rb, Cs; 0 ≤ x ≤ 1), has been investigated to illuminate the relationship between composition and structure. Topochemical synthesis of the solid solutions from combinations of various alkali metal cations has been achieved by reacting pure end members (ALaNb₂O₇) at appropriate ratios and temperatures. All adjacent sets of alkali metals (Li/Na, Na/K, K/Rb, and Rb/Cs) readily formed solid solutions, while only the one non-adjacent solid solution, K_1−xCs_xLaNb₂O₇ (K/Cs), could be obtained. Local cation coordination and the corresponding layer alignments vary as a function of composition where the relative concentration of the larger cation dictates structure. Thermal analysis of the solid solutions, A_1−xA′_xLaNb₂O₇ (A/A′ = Li, Na, K) showed that the lithium- and sodium-containing compositions were thermally unstable. This study demonstrates that the systematic variation in average cation sizes in the solid solution series allows for structural control in these important perovskite hosts. Full article

Microbial hydrocarbon degradation mediated by natural/modified clay minerals represents an eco-friendly and economically viable remediation strategy for hydrocarbon contamination. However, its effects are not always positive as they depend on multiple factors, including clay mineral types, modification methods, microbial species, and hydrocarbon substrates. This review systematically synthesizes existing fragmented studies concerning the impacts of natural clay minerals, modified clay minerals (acid/alkali/thermal/organic/metal ion), and clay minerals containing composite materials on microbial hydrocarbon biodegradation. Based on current findings, future research should prioritize the following recommendations: (1) avoid using concentrated strong acids in acid activation; (2) exclude metal cations that induce strong adsorption (reducing hydrocarbon bioavailability) or trigger excessive interlayer hydrolysis (some trivalent cations) in metal cation modification; (3) eliminate biologically toxic agents during organic modification; and (4) expand understanding of alkali/thermally modified clay minerals and clay mineral-containing composite materials in this direction. Natural/modified clay mineral-mediated microbial degradation is a highly promising remediation technology for hydrocarbon contamination and poised to advance and achieve breakthroughs through continuous synthesis of knowledge and innovation. Full article

Alkali metal-modified M-ZSM-5 zeolites (M: Li⁺, Na⁺, K⁺) were synthesized by cationic exchange and characterized using ICP-MS, XRD, N₂ adsorption–desorption, Py-IR and NH₃-TPD techniques to evaluate their elemental composition, structure, textural and acidic properties. In addition, XPS and DFT calculations were employed to study the effects of metal ion doping on the electronic structure and catalytic behavior. The latter catalytic performance was assessed in the methanol-to-olefin (MTO) reaction. The results showed that alkali metal doping facilitated the enhancement of the zeolite structural stability, adjustment of acid density, and increase in the adsorption energy of light olefins onto the active sites. During the reaction, olefin products shifted from Brønsted acid sites to alkali metal sites, effectively minimizing hydrogen transfer reactions. This change in the active site nature promoted the olefin cycle, resulting in higher yields in propylene and butylenes, reduced coke deposition, and prolonged catalyst lifetime. Among all zeolites, Li-exchanged ZSM-5 exhibited the best and extending the catalyst lifetime by 5 h. Full article

The reaction of 4,4′-bipyridine (C₁₀H₈N₂) with the alkali metal pentacyanocyclopentadienides [Na{C₅(CN)₅}(MeOH)] and [KC₅(CN)₅] gives the coordination polymers [Na{C₅(CN)₅}(EtOH)(H₂O)(C₁₀H₈N₂)] (1) and [K{C₅(CN)₅}(H₂O)₂] • 2 (C₁₀H₈N₂) (2) after recrystallization from EtOH. Both compounds show octahedral coordination around the metal ion with a NaN₄O₂ and KN₂O₄ environment. The [C₅(CN)₅] acts as a 1,1-bridging ligand in 1 and a 1,2-bridging ligand in 2. The 4,4′-bipyridine acts as a N,N′-bridging ligand between dimeric [Na₂(EtOH)₂(H₂O)₂(µ-{C₅(CN)₅}₂] units, while it acts only as a guest molecule in the voids between polymeric [K(µ-H₂O)_4/2{µ-C₅(CN)₅}_2/2]_∞ chains. Both compounds employ multiple hydrogen bonds and π stacking to stabilize the crystalline structures. Full article

The NRAMP (Natural Resistance-Associated Macrophage Protein) family plays a pivotal role as membrane transporters in plants’ responses to heavy metal stress. This study identified 12 NRAMP genes in Sorghum bicolor (sorghum) and performed a comprehensive bioinformatics analysis. The SbNRAMP genes are distributed across seven sorghum chromosomes. In-depth analyses of gene structure, conserved motifs, collinearity, and phylogeny indicated that the SbNRAMP family is divided into three subfamilies, each exhibiting unique structural and motif characteristics. Collinearity analysis suggested that large-fragment duplications, rather than tandem duplications, were responsible for the expansion of the SbNRAMP family, resulting in a greater number of genes compared to Arabidopsis thaliana and rice. Transcriptome analysis of the aboveground and underground parts of sorghum seedlings under saline–alkali stress revealed that SbNRAMP5 is a key hub gene exhibiting tissue-specific expression. Furthermore, qRT-PCR analysis following exposure to Cd, Mn, or Zn treatments revealed differential expression among the SbNRAMP genes. Subcellular localization predictions indicated that all twelve NRAMPs are primarily located in the plasma membrane, with nine to twelve transmembrane domains, consistent with their function in metal ion transport. Experimental evidence confirmed that SbNRAMP6 is localized in the plasma membrane. These findings establish a foundation for a deeper understanding of the structure and function of the sorghum NRAMP gene family. Full article

Batteries are a cornerstone of modern technology that supports a wide range of applications including portable electronics, electric vehicles and large-scale energy storage for renewable power systems. Despite their widespread use, commercial Li-ion batteries are limited by the mineral resources of Li. The rapidly growing battery market demands alternative battery systems, such as non-alkali metal-ion batteries, that are capable of delivering comparative energy densities. In the meantime, improving the performance of the batteries via generating sustainable strategies has been broadly studied. Proteins, as re naturally evolved macromolecules that possess diverse structures and functional groups, have been demonstrated to be able to transport various metallic ions inside bio-organisms. Therefore, active studies have been carried out on the use of natural proteins (e.g., zein, soy, fibroin, bovine serum albumin, etc.) to enhance the electrochemical performance of non-alkali metal-ion batteries. This review provides a comprehensive summary of recent advances on the studies of protein-based strategies for non-alkali metal-ion batteries and outlines perspectives for future sustainable electrochemical energy storage systems. Full article

The Gabal Um Samra (GUS) compound intrusion in the Eastern Desert of Egypt consists of a co-magmatic series of syenogranite and alkali feldspar granite. Accessory minerals (e.g., zircon, monazite, allanite) are abundant. Geochemically, the GUS intrusion is a classic A-type granite. It is extensively fractionated, enriched in large ion lithophile elements and high field strength elements, and depleted in Ba, Sr, K, and Ti. Normalized rare earth element patterns are nearly flat, without any lanthanide tetrad anomalies, but with distinct negative Eu anomalies (Eu/Eu* = 0.14–0.22) due to feldspar fractionation. Paired Zr-Hf and Y-Ho element systematics indicate igneous rather than hydrothermal processes. The petrogenesis of the comparatively unaltered GUS intrusion offers an opportunity to refine the standard model for post-collisional felsic magmatism in the Neoproterozoic Arabian–Nubian Shield. It is explained by the partial melting of juvenile crust induced by lithospheric delamination, followed by extensive fractional crystallization. A quantitative mass-balance model shows that the granite varieties of the GUS intrusion plausibly represent liquids along a single liquid line of descent; but, if so, the more evolved, later pulses display anomalous enrichment in Rb, Nb, Ta, U, and REE. The most plausible source for this enrichment is the extraction of small-degree residual melts from earlier pulses and the mixing of the melts into the later pulses, an energetically favorable process we call “auto-assimilation”. A quantitative model shows that the residual liquid after 97.5% crystallization of the syenogranite can fit the major oxide and trace element data in the alkali feldspar granite if 0.07% by mass of this melt is added to the evolving system for each 1% crystal fractionation by mass. The GUS intrusion represents an example of moderate rare metal enrichment and concentration to sub-economic grade by auto-assimilation. Similar processes may affect intrusions that feature higher grade mineralization, but the evidence is often obscured by the extensive alteration of those deposits. Full article

The stabilization of heavy metal elements, such as zinc, in the form of ions within the glass-ceramics represents a valuable approach to addressing environmental pollution caused by heavy metals. This study investigates the feasibility and physicochemical properties of diopside-based glass-ceramics synthesized from zinc-containing smelting slag. The zinc-rich smelting slag is abundant in SiO₂, Al₂O₃, CaO, and other constituents, thereby providing cost-effective and efficient raw materials for glass-ceramic production. The conversion of zinc-containing smelting slag into glass-ceramics was achieved through a melting process. We analyzed the effects of varying doping levels on the properties of the resulting glass-ceramics. The results indicated that as the doping level of smelting slag increases, the crystallization temperature of the glass-ceramics decreases while the crystal phases of diopside and anorthite progressively increase, significantly enhancing both mechanical strength and chemical stability. Notably, when the doping level reaches 60%, these glass-ceramics exhibit remarkable physical properties, including high density (3.12 g/cm³), Vickers hardness (16.60 GPa), and excellent flexural strength (150.75 MPa). Furthermore, with increasing amounts of doped smelting slag, there are substantial improvements in acid resistance, alkali resistance, and corrosion resistance in these materials. Raman spectroscopy and EDS analysis further verified a uniform distribution of the crystal phase and effective immobilization of heavy metal zinc. Full article

MBenes, an emerging family of two-dimensional transition metal boride materials, are gaining prominence in alkali metal-ion battery research owing to their distinctive stratified architecture, enhanced charge transport properties, and exceptional electrochemical durability. This analysis provides a comprehensive examination of morphological characteristics and fabrication protocols for MBenes, with particular focus on strategies for optimizing energy storage metrics through controlled adjustment of interlayer distance and tailored surface modifications. The discussion highlights these materials’ unique capability to host substantial alkali metal ions, translating to exceptional longevity during charge–discharge cycling and remarkable high-current performance in both lithium and sodium battery systems. Current obstacles to materials development are critically evaluated, encompassing precision control in nanoscale synthesis, reproducibility in large-scale production, enhancement of thermodynamic stability, and eco-friendly processing requirements. Prospective research pathways are proposed, including sustainable manufacturing innovations, atomic-level structural tailoring through computational modeling, and expansion into hybrid energy storage-conversion platforms. By integrating fundamental material science principles with practical engineering considerations, this work seeks to establish actionable frameworks for advancing MBene-based technologies toward next-generation electrochemical storage solutions with enhanced energy density and operational reliability. Full article

Volatile fatty acids (VFA) are valuable intermediates with growing demand in chemical, pharmaceutical, and environmental applications. Their sustainable production from organic waste is increasingly explored in the context of circular economy and biorefinery models. This study investigates the co-fermentation of waste-activated sludge (WAS) and the organic fraction of municipal solid waste (OFMSW) as a strategy for integrated VFA and biogas production. Semi-continuous experiments were carried out to assess the effect of the substrates ratio (WAS:OFMSW = 90:10 and 30:70), hydraulic retention time (HRT), and pH control (5, 9, no control) on VFA yield and composition. Results showed that higher OFMSW content and alkaline conditions favoured VFA production, with a maximum yield of 144.9 mgHAc·gVS⁻¹ at pH 9 and 70:30 ratio. Acetate dominated, while butyrate production peaked at 114.1 mgHBu·gVS⁻¹ under high sludge conditions. However, the addition of alkali required for pH control may lead to excessive accumulation of alkaline-earth metal ions, which can disrupt biological processes due to their potential toxicity. Anaerobic digestion of fermentation residues enhanced biomethane yields significantly (0.27 NL·gVS⁻¹ vs. 0.05 NL·gVS⁻¹ from raw sludge). The proposed process demonstrates potential for converting wastewater treatment plants into biorefineries, maximising resource recovery while reducing environmental impact. Full article

This study aimed to evaluate the effects of studying the effects of the alkali metal ion complexes (AMIC) on the rumen of lambs. Eighteen 3-month-old male Hu lambs (30 ± 2.5 kg) were randomly assigned to three groups (n = 6). Dietary treatments were: control group (CG, base diet), group C1 (base diet + 0.15% AMIC), and group C2 (base diet + 0.30% AMIC). After 60 days of feeding, samples were collected for analysis. Compared with CG, rumen weight significantly increased in both C1 and C2 (p < 0.05). In C2, average daily gain (ADG), bacterial crude protein (BCP), propionic acid concentration, and rumen papillary length were significantly higher than in CG (p < 0.05). Rumen microbiota analysis showed that AMIC supplementation changed the microbial community composition, increasing the relative abundance of fiber-degrading bacteria (e.g., Prevotellaceae_UCG-001) and decreasing pathogenic Proteobacteria. In particular, rumen papillary length positively correlated with Unclassified Oscillospiraceae, Candidatus Saccharimonas, and Unclassified Clostridia vadinBB60 group. Metabolomic analysis revealed that quercetin 3-O-glucuronide levels increased in a dose-dependent manner with higher AMIC. This metabolite positively correlated with Prevotellaceae_UCG-001 abundance and ADG. At 0.30% AMIC, phospholipids PC(18:0/18:4(6Z,9Z,12Z,15Z)) and PE(18:0/16:1(9Z)) were significantly upregulated, and both positively correlated with Candidatus Saccharimonas, Unclassified Clostridia vadinBB60 group, and papillary morphology. In summary, AMIC supplementation affected metabolism by modulating the rumen microbiota, thereby promoting energy absorption and growth. The 0.30% AMIC inclusion significantly enhanced rumen papilla growth, increased the absorption area, promoted propionic acid production, reduced the acetic acid to propionic acid ratio, and ultimately improved the growth rate of Hu lambs. Thus, adding 0.30% AMIC was associated with improved growth performance. Full article

Aza-crown ether structures have been proven to be effective in constructing fluorescent biosensors for selectively detecting and imaging alkali metal ions in biological environments. However, choosing the right aza-crown ether for a specific alkali metal ion remains challenging for synthetic chemists because theoretical guidance on the chelating activities between aza-crown ethers and alkali metal ions has not been available up to now. Predicting the physical properties of the chelator–metal complexations poses a greater challenge due to the numerous quantum mechanical functionals and basis sets to be used in any theoretical investigation. In this study, we report a theoretical investigation of different aza-crown ether structures and their selectivities to alkali metal ions via a novel relationship between the binding energy and charge transfer calculated using twelve different quantum mechanical methods, using a myriad of bases, within the Jacob’s Ladder of Chemical Accuracies. Furthermore, this report represents a guide for the synthetic chemist in the selection of aza-crown ethers in the capturing of specific alkali metal ions, primary objectives, while benchmarking different quantum mechanical calculations, as a secondary objective. Full article

Alkali-activated materials, as a low-carbon cementitious material, are widely known for their excellent durability and mechanical properties. In recent years, the modification of alkali-activated materials using biochar has gradually attracted attention. Fibrous biochar has a highly porous structure and large specific surface area, which can effectively adsorb alkaline ions in alkali-activated materials, thereby improving their pore structure and density. Additionally, the surface of the biochar contains abundant functional groups and chemically reactive sites. These can interact with the active components in alkali-activated materials, forming stable composite phases. This interaction further enhances the material’s mechanical strength and durability. Moreover, the incorporation of biochar endows alkali-activated materials with special adsorption capabilities and environmental remediation functions. For instance, they can adsorb heavy metal ions and organic pollutants from water, offering significant environmental benefits. However, research on biochar-modified alkali-activated materials is still in the exploratory phase. There are several challenges, such as the unclear mechanisms of how biochar preparation conditions and performance parameters affect the modification outcomes, and the need for further investigation into the compatibility and long-term stability of biochar with alkali-activated materials. Future research should focus on these issues to promote the widespread application of biochar-modified alkali-activated materials. Full article