Search Results (269)

LiAlH₄ reduction of tert-butyl (S)-butyl(1-((2-cycloheptylethyl)amino)-1-oxo-3-phenylpropan-2-yl)carbamate (1) gave imidazolidine 2, while treatment with lithium diisopropylamide furnished the β-elimination product, cinnamamide 3. Both products were fully characterized. Reductive cyclization of N-alkylated-N-Boc-protected amino acid amides with LiAlH₄ may be a viable synthetic method for trisubstituted chiral imidazolidines. Full article

In the realm of computational biomechanics, quantifying the reliability of surface-engineered implants is critical yet challenging due to material anisotropy and experimental limitations. Standard deterministic approaches often fail to capture the failure probability of brittle coatings, compromising the accuracy of lifespan predictions. This study’s originality lies in a stochastic framework that addresses titanium boride data scarcity using a geometric decision node (GDN). By autonomously switching between Palmqvist and Radial-Median regimes, the GDN eliminates deterministic bias and provides a failure-probability-based reliability assessment, thereby surpassing the limitations of conventional models. The evaluation was carried out on powder-pack borided Ti6Al4V layers produced at 1000 °C (10, 15, and 20 h). By combining instrumented Berkovich nanoindentation (N = 14, hardness scatter 17.6–34.8 GPa) with a Monte Carlo simulation algorithm (n = 10,000), we successfully modeled the stochastic brittle failure of the coating. The computational model, governed by a multivariate joint probability density function (JPDF), revealed a mixed-mode fracture mechanism where 77.9% of the virtual population developed radial cracks while 22.1% re mained in the Palmqvist regime. Weibull statistical analysis yielded a characteristic toughness of 2.25 MPa·m^1/2 and a low modulus of m = 1.58. This low modulus mathematically quantifies the coating’s sensitivity to microstructural defects, demonstrating that probabilistic algorithms—rather than mean-value deterministic calculations—are essential for ensuring the structural integrity of borided components in biomechanical design applications. Full article

Aluminum–lithium (Al-Li) alloys have attracted great interests in aerospace, solid propellants, and explosives industries. However, the practical use of Al-Li remains challenging because of instability during storage. Poor corrosion resistance and passivation of the Al-Li alloys are ascribed to the surface cracking of the oxidation layer. Using a variety of ab initio quantum chemistry methods, the cracking mechanisms of Al/Li/O oxides induced by H₂O, LiOH, and Li₂O have been revealed theoretically by means of Al₄O₆ and Al₈O₁₂ cluster models. All six reactions are shown to be highly exergonic dissociative adsorption processes. In terms of the Gibbs free energy profiles, the adsorption energy and reactivity are in the order Li₂O > LiOH > H₂O, which is independent of sizes of clusters. However, cluster size does have an impact on the adsorption energies of H₂O, LiOH, and Li₂O. For the reactions of H₂O, the energetic routes are dominated by proton transfer and followed by the O-Al bond cleavage to generate trench or protrusion structures. However, proton transfer is inhibited considerably by the O-Li interaction. As the Li atom migrates to form various Li-O coordinates along with the O-Al bond cleavage, the alumina clusters are cracked stepwisely through the interlayer O-Al bond association or displacement. The edge Al sites are always less reactive than the topmost surface Al. The Li atoms are prone to migrate from the edge to the surface as accompanied by the O-Al bond rearrangement. Present calculations provide a deep understanding of the oxidation behavior of the Al-Li alloys and present new insights towards increasing storage stability. Full article

Layered nickel-rich cathodes are regarded as promising cathode materials for lithium-ion batteries (LIBs) due to their higher electrochemical capacities and lower cost. However, the development and commercial application of nickel-rich cathodes are severely hindered by significant capacity fading under a high charge cut-off voltage (4.5 V), which arises from interfacial instability and bulk structural degradation during charge–discharge processes. In this study, a two-step double-coating strategy was innovatively adopted to successfully synthesize Al₂O₃/LiBO₂ co-coated LiNi_0.71Co_0.09Mn_0.2O₂ cathode material (denoted as NCM-Al/B). X-ray photoelectron spectroscopy (XPS) verified that Al existed stably in the form of Al³⁺, and B formed B-O-M covalent bonds with transition metals (Ni/Co/Mn), constructing a dual-element synergistic interface. This interface significantly reduced the surface Ni³⁺ content and enhanced the structural stability by suppressing the H₂→H₃ phase transition. The NCM-Al/B material exhibits excellent electrochemical performance: it maintains a remarkable cycling stability with a capacity retention of 91.6% after 100 cycles at 1 C and 25 °C and delivers a discharge capacity of 156.6 mAh·g⁻¹ with a capacity retention of 75.4% after 100 cycles at a high rate of 1 C. This work establishes a chemically driven double-coating strategy and provides a new paradigm for optimizing the performance of high-nickel cathode materials. Full article

This study investigates the hydrometallurgical purification of the acidic leachate from spent LiCoO₂-based lithium batteries, focusing on the selective removal of Cu, Mn, and Ni while monitoring co-precipitation of Fe and Al and minimizing Co and Li losses. Thermodynamic modelling using HSC Chemistry 10 and Hydra/Medusa guided the design of precipitation conditions. The optimal Cu precipitation was achieved using Na₂S (Na₂S:Cu = 4:1, 20 °C, 5 min, 300 rpm), yielding > 99% removal. Mn was efficiently precipitated as MnO₂ using KMnO₄ (KMnO₄:Mn = 1:1, 20 °C, pH ≈ 2, 10–15 min, ≈97% efficiency). Ni was recovered as [Ni(DMG)₂] under DMG:Ni = 5:1, 80 °C, 15 min, pH ≈ 5, achieving ≈99% removal. Sequential 2 L experiments (precipitation order: Cu → Mn → Ni) validated the scalability of the process. Cu and Ni removal remained high (>95%), while Mn efficiency slightly decreased (≈91%) due to kinetic and redox inhomogeneity. No significant precipitation of Co and Li was observed, leaving them in solution and concentrating from 12.9 to 18.8 g·L⁻¹ and 2.71 to 3.50 g·L⁻¹, respectively, with total losses of <1%. The resulting CuS, MnO₂, and [Ni(DMG)₂] precipitates exhibited moderate purity (46–63%) but represented valuable secondary raw materials. Overall, sequential precipitation under optimized conditions demonstrates robust, selective removal of accompanying metals while concentrating Co and Li, providing an efficient and scalable route for LIBs leachate valorisation. Full article

Gray mold disease severely impacts the yield and quality of Panax notoginseng (Burkill) F. H. Chen ex C. Chow & W.G. Huang. In this study, a strain of Botrytis fabiopsis J. Zhang, G.N. Wu & G.Q. Li labeled as 3-3 was isolated from the leaves affected by gray mould disease of P. notoginseng, identified as a novel pathogen for this plant. Targeting the strain 3-3, an antagonistic bacterial strain X30 was isolated from the leaves of P. notoginseng and was preliminarily identified as Bacillus amyloliquefaciens (Fukumoto) Priest et al. through morphological and molecular biological analyses. The in vitro antifungal test showed that strain X30, at a concentration of 1 × 10⁸ CFU mL⁻¹, had an inhibition rate of 84.63% against the B. fabiopsis strain 3-3, and it exhibited broad-spectrum antifungal activity against other major pathogenic fungi of P. notoginseng, including Alternaria alternata (Fr.) Keissl., Rhizoctonia solani J.G. Kühn and others. Additionally, strain X30 was found to produce ammonia, fix nitrogen, secrete plant growth hormones, and release multiple hydrolytic enzymes, thus possessing both plant-growth-promoting and antimicrobial traits. In pot experiments, an X30 suspension at 1 × 10⁸ CFU mL⁻¹ achieved 61.04% control rate against B. fabiopsis. Using non-targeted metabolomics, compounds in the culture filtrate of strain X30 were analyzed, and two organic acid compounds with antimicrobial activity were identified. Among them, phenylpyruvic acid had an EC₅₀ value of 312 µg mL⁻¹ against pathogen 3-3, while 2,6-dihydroxybenzoic acid had an EC₅₀ value of 660 µg mL⁻¹. B. amyloliquefaciens X30 provides a theoretical basis for developing green and efficient biocontrol agents against gray mould in P. notoginseng. Full article

The horst and graben system in Western Anatolia lies on the eastern boundary of the Aegean extensional system, one of the most active extensional zones in the world. The Şahinali coal basin is located south of the Büyük Menderes Graben, which is part of this system. This study examines the rare earth elements and yttrium (REY) geochemistry, accumulation conditions, and economic potential of the Şahinali coals. Compared to world coals, the REE concentration in Şahinali coals (208.3 ppm) is quite high, and all REY groups are slightly enriched. Light REY (LREY) is dominant compared to medium REY (MREY) and heavy REY (HREY). The most abundant element in this group is Ce, reaching a concentration of 123.3 ppm. REY distribution patterns indicate H-type enrichment in most samples and, to a lesser extent, M-H-type enrichment. Element ratios (Al₂O₃/TiO₂, TiO₂/Zr, La/Sc, Co/Th) and REY anomalies (Ce, Eu, Gd) indicate that the sedimentary input is predominantly derived from felsic rocks, with limited intermediate to mafic contributions. SEM-EDS findings and correlation analyses indicate that REY are predominantly associated with aluminosilicate minerals. LREY-Th and MREY/HREY-Y relationships are supported by monazite and Y-rich illitic K-aluminosilicates. Paleoenvironmental indicators (V/Cr, Ni/Co, U/Th, Sr/Cu, Rb/Sr, Sr/Ba) indicate that the coal accumulated under oxic–suboxic, warm and humid conditions. The average REY oxide (REO) content slightly exceeds the commonly cited 1000 ppm screening threshold for coal ash. The majority of samples contain elevated proportions of critical REY (30.7%–54.3%) and show promising outlook coefficients (C_outl: 0.8–1.7). Together, these results indicate a favourable compositional signature for preliminary REY resource screening in the Şahinali coals, particularly with respect to elements relevant for high-technology applications. Full article

The efficient separation of H₂ from CH₄ is crucial for hydrogen purification from industrial off-gases using pressure swing adsorption (PSA). In this study, the competitive adsorption behavior of H₂/CH₄ on LTA zeolites was systematically investigated via grand canonical Monte Carlo (GCMC) simulations, with a focus on the effects of cation type (Na⁺, Li⁺, Ca²⁺, Mg²⁺), Si/Al ratio (1–1.5), temperature (298–318 K), and pressure (0.2–2 MPa). The results reveal that CH₄ favors β-cages as excellent adsorption sites with high population density, followed by the regions adjacent to the cations or framework oxygen atoms of the eight-membered rings. In contrast, H₂ is uniformly distributed throughout all the channels. Cations with higher valence and smaller ionic radii (e.g., Mg²⁺) enhance CH₄ adsorption capacity and diffusion more effectively than monovalent or larger cations. Increasing the Si/Al ratio reduces cation content and exposes more framework oxygen atoms, particularly those in Si–O–Si environments, which improve CH₄ adsorption. Elevated temperature weakens CH₄ adsorption while promoting H₂ diffusion and pore occupancy. Although higher pressure increases the uptake of both gases, H₂ adsorption rises more substantially and distributes more widely, leading to a decrease in CH₄/H₂ selectivity. Full article

The increasing demand for lithium-ion batteries (LIBs) has intensified the need for efficient lithium (Li) recovery from secondary sources. This study focuses on anti-solvent crystallization for the recovery of high-purity lithium hydroxide monohydrate (LiOH·H₂O) from a Li-rich leachate, derived from the flue dust of a pilot-scale pyrometallurgical process for LIB material recycling. To optimize product yield and purity, a series of experiments were performed, focusing on the influence of parameters such as solvent type, organic-to-aqueous (O/A) volumetric ratio, crystallization time, stirring rate, and anti-solvent addition rate. Acetone was identified as the most effective anti-solvent, producing rectangular cuboid crystals with approximately 90% Li recovery and around 95% purity, under optimized conditions (O/A = 4, 3 h, 150 rpm, and solvent flow rate of 5 mL/min). The flow rate influenced crystal morphology and impurity entrapment, with 5 mL/min favoring nucleation-dominated crystallization regime, producing ~20 μm of well-dispersed crystals with reduced impurity incorporation. SEM-EDS, surface washing, and gradual dissolution of obtained LiOH·H₂O crystals revealed that the impurities sodium (Na), potassium (K), aluminum (Al), calcium (Ca) and chromium (Cr) were crystallized as conglomerates. It was found that Na, K, Al, and Ca primarily crystallized as highly soluble conglomerates, while Cr was crystallized as a lowly soluble conglomerate impurity. In contrast Zn was distributed throughout the crystal bulk, suggesting either the entrapment of soluble zincate species within the growing crystals or the formation of mixed Li-Zn phase. Therefore, to achieve battery-grade purity, further purification measures are necessary. Full article

This study investigated the effect of mechanical activation on the physicochemical properties of lepidolite and the leaching behavior of mechanically activated samples in sulfuric acid (H₂SO₄). Lepidolite was mechanically activated using a high-energy planetary ball mill (PBM) at 400 RPM with a 20:1 ball-to-feed weight ratio (BFR, g:g) and the samples activated for different durations were characterized for amorphous phase content, particle size, and morphology using various solid analyses. X-ray diffraction (XRD) revealed the progressive amorphization of lepidolite, with the amorphous fraction increased from 34.1% (unactivated) to 81.4% after 60 min of mechanical activation. Scanning electron microscopy (SEM) showed that mechanically activated particles became fluffy and rounded, whereas unactivated particles retained lamellar and angular shapes. The reactivity of minerals after mechanical activation was evaluated through a 2 M H₂SO₄ leaching test at different leaching temperatures (25–80 °C) and time periods (30–180 min). Although the leaching efficiencies of Li and Al slightly improved at higher leaching temperatures and longer leaching times, the leaching of these metals was primarily governed by the mechanical activation time. The highest Li and Al leaching efficiencies—87.0% for Li and 79.4% for Al—were obtained from lepidolite that was mechanically activated for 60 min under leaching conditions of 80 °C and a 10% (w/v) solid/liquid (S/L) ratio for 30 min. The elemental mapping images of leaching feed and residue produced via energy dispersive spectroscopy (EDS) indicated that unactivated particles in the leaching residue had much higher metal content than mechanically activated particles. Kinetic analysis further suggested that leaching predominantly occurs at mechanically activated sites and the apparent activation energies calculated in this study (<3.1 kJ·mol⁻¹) indicate diffusion-controlled behavior with weak temperature dependence. This result confirmed that mechanical activation significantly improves reactivity and that the residual unleached fraction can be attributed to unactivated particles. Full article

Tiger nut (Cyperus esculentus L.) is a relatively neglected tuber crop with notable nutritional, functional, and ecological value. The primary objective of this study was to evaluate the biological properties and selected nutritional parameters of tiger nut tubers and oil, including antioxidant activity, total phenolic content (TPC), fatty acid (FA) profile, health-related lipid indices, and mineral composition. Methods: Natural and peeled tiger nut tubers, as well as commercially available tiger nut oil (yellow variety, Valencia, Spain), were analyzed. Antioxidant activity was measured spectrophotometrically using the DPPH method. The content of TPC was determined using the Folin–Ciocalteu assay. Fatty acid composition was analyzed by gas chromatography coupled with flame ionization detection, and these data were used to calculate the PUFA/SFA (P/S) ratio, atherogenicity (AI), thrombogenicity (TI) index, and hypocholesterolemic/hypercholesterolemic (h/H) ratio. Macro- and microelement contents were quantified using inductively coupled plasma optical emission spectrometry. Estimated daily intake (EDI), target hazard quotient (THQ), and total THQ (TTHQ) were calculated to assess potential health risks. Results: Natural tiger nut tubers exhibited substantially higher antioxidant activity and TPC compared to peeled tubers, suggesting that the peel is the primary reservoir of phenolic compounds. Strong antioxidant activity was observed in tiger nut oil (64.82 ± 2.59 mg TEAC/L). Oleic acid (C18:1cis n-9) was identified as the predominant FA across all samples, thus contributing positively to favorable health lipid indices (P/S > 0.50, low AI and TI, high h/H ratio). Potassium was the most abundant macroelement in natural and peeled tiger nut tubers. The overall trend of microelement levels in these samples was as follows: Al > Fe > Zn > Cu > Sr > Mn > Li > Ba > Se > As > Cr. All THQ and TTHQ values were below 1, indicating no appreciable health risk associated with consumption. Conclusions: These findings support the use of tiger nuts as a functionally valuable ingredient in health-oriented food products. Full article

The mineral matter in coal has great significance for geological evolution, and clean and fractional utilization. The Laochang mining area is one of the largest anthracite coal production bases in Southern China, and the most important coal energy base in Yunnan province, China. This study investigates the composition and mode of occurrence of mineral matter in the Laochang coals to reveal the sediment provenance, sedimentary environment, and hydrothermal fluids. The predominant minerals in the Laochang coals include oxide (quartz, anatase), clay (kaolinite, illite/smectite mixed layer), sulfide (pyrite, sphalerite), phosphate (xenotime, monazite, goyazite–gorceixite), and carbonate (calcite, dolomite, sideroplesite, siderite). The minerals in the Laochang coals are dominated by quartz (2.4~54.8%) and kaolinite (3.4~39.2%), followed by illite, smectite, muscovite, calcite, pyrite, and anatase. Quartz and dolomite in SB-7+8 coal have the highest proportions, reaching 54.8% and 17.3%. The modes of occurrence of minerals reflect that the Laochang coals are affected by the epigenetic hydrothermal fluids and seawater. The chalcophile elements Hg, Pb, Se, and Cr, and lithophile elements Li, Nb, Ta, Zr, Hf, and REY are slightly enriched in XB-3 coal, which is attributed to the intrusion of seawater and the supply of terrestrial detrital materials, respectively. REY is dominated by LREY, followed by MREY, and a lower level of HREY in the Laochang coals, which have a high fractionation degree. The REY enrichment H-type is influenced by the hydrothermal fluids. Based on the relationship between Al₂O₃ and TiO₂, Al₂O₃/TiO₂ and Nb/Yb, and the negative anomaly Eu, the detrital material in the erosion source area of the Laochang coal is derived from the Emeishan Large Igneous Province basalt and felsic–intermediate rocks. Full article

The increasing demand for lithium and the limited availability of high-grade resources have accelerated interest in lithium-bearing clays as a promising alternative, despite their relatively lower lithium content. Lithium extraction from such clay minerals typically requires thermal treatment or acid leaching to disrupt the clay crystal lattice and enhance lithium solubility. The enrichment tailings from the Kırka Boron Processing Plant in Türkiye consist predominantly of dolomite-rich clay minerals and contain approximately 900–1200 ppm Li. Considering the substantial quantities of these tailings currently stored on-site, recovering lithium and converting these materials into a valuable resource would be of significant economic importance. However, due to their mineralogical composition, conventional acid leaching of these tailings demands relatively high sulfuric acid consumption (1.5–2.0 M H₂SO₄). This leads to excessively low solution pH and the generation of highly acidic waste streams, while also promoting the co-dissolution of iron (Fe) and aluminum (Al) ions at pH levels below 2, which negatively affects lithium recovery and downstream processing. In this study, mechanical activation was applied to the tailings prior to acid leaching. As a result, the acid requirement to achieve lithium extraction efficiencies of 90% and above was successfully reduced from 1.5 M to 1.0 M H₂SO₄. Moreover, solution pH was maintained near neutral (~7), and the undesirable dissolution of Fe and Al ions was effectively suppressed and kept under control. Full article

This study investigated the solvent extraction of a high-nickel-content metal solution using nickel-preloaded extractants. A synthetic high-nickel lithium-ion battery (LIB) black mass leachate was prepared to extract Cu, Al, and Mn using Ni-preloaded D2EHPA (Ni-D2EHPA). Then, Co was extracted from the raffinate using Ni-preloaded PC88A (Ni-PC88A). The results showed that Ni-preloaded D2EHPA extracted more than 99% of the Al, Cu, and Mn. Co was also co-extracted at a rate of 53%, but 99% of the Co was scrubbed with 0.2 M H₂SO₄. Co was extracted from the raffinate using Ni-PC88A at a rate of 99% with 1.0 O/A. Finally, 99% of the Co in the organic phase was stripped using 2.0 M sulfuric acid. After Co extraction using Ni-PC88A, 80 g/L Ni and 1.38 g/L Li remained in the raffinate. Crude nickel sulfate was produced from the raffinate after precipitation of Li as lithium carbonate. Full article

In this work, density functional theory (DFT)-based first-principles investigations are performed by Generalized Gradient Approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE) functional in the CASTEP code. These simulations provide the insights of the structural, electronic, optical, thermodynamic, mechanical and hydrogen storage gravimetric ratios of lithium-based tetrahydrides (LiBH₄, LiAlH₄, and LiMnH₄) for hydrogen storage and photovoltaic (PV) applications. All these structures crystallize in orthorhombic Cmcm (No. 63) geometry with different lattice parameters and bonding strengths. Thermodynamic stabilities of hydrides are obtained by dispersion of phonons and phonon density of states. The measured band gaps of hydrides are 3.81 eV (LiBH₄), 4.60 eV (LiAlH₄), and 0.53 eV (LiMnH₄), which are calculated by GGA-PBE approach. Moreover, the optical characteristics with strong optical activity are observed from visible to ultraviolet (2 eV to 6 eV) regions. High dielectric response between 6 and 8 and absorption coefficient up to 10⁵ cm⁻¹ for hydrides are observed. Debye temperature has exceeded from 300 K to 600 K for all hydrides and saturation occurred closer to Dulong–Petit limit ~75 J mol⁻¹ K⁻¹. Mechanical stability in hydrides has been observed by Born-Hung mechanical stability criterion, demonstrating ductile nature. These natural hydrides have shown exceptional hydrogen storage capacities, as 18.5 wt% for LiBH₄, 10.6 wt% for LiAlH₄, and 6.1 wt% for LiMnH₄, are measured; these values have exceeded the U.S department of energy (DOE) targets (5.5 wt% H₂). These analyses prove that LiXH₄ (X = B, Al, Mn) hydrides are promising candidates for solid state hydrogen storage materials. Full article