Search Results (672)

Juniperus species form critical, long-lived high-mountain forest ecosystems in Central Asia, serving essential phytocoenotic and ecological functions in environmentally challenging habitats. However, the relationships between the elemental composition of these evergreen conifers and their underlying soils remain poorly understood. This study evaluated and compared the distribution of major elements (Fe, Ca, P, Mg, Al, Na, K, S), trace elements (Cu, Pb, Zn, Ni, Co, Mn, As, Cd, Cr, Mo, U, Th, Sr, Sb, Bi, V, La, Ba, Ti, B, W, Sc, Zr, Tl, Ta, Nb, Se, Te, Ga, Cs, Ge, Hf, Rb, Sn and others), and environmental pollution indices (Igeo, EF, CF, BAF) in plant tissues (leaves and cones) and canopy soils of three key juniper species (Juniperus seravschanica, J. turkestanica, and J. semiglobosa) in the Fann Mountains, Tajikistan. Soil and plant samples were collected across natural habitats and analyzed for total chemical composition using ICP-OES. The soils showed a near-neutral reaction (pH 7.02–7.42 in H₂O and 6.41–7.15 in KCl), with considerable variability in Corg. content (5.04%–21.82%) and Nt content (0.337%–1.149%) in the humus (A) horizons. Geochemical indices (Igeo up to 2.42, EF up to 35.30) indicated noticeable soil enrichment and localized contamination by arsenic (As) and cadmium (Cd), likely driven by a combination of regional industrial and mining activities alongside natural geogenic enrichment. Across all sites, elemental concentrations followed a consistent sequence: soil > leaves ≈ cones. Heavy metals in plant tissues remained well below toxic thresholds. High organ-specific partitioning was observed: K predominated in cones (K > Ca > P), whereas Ca and Fe accumulated predominantly in leaves (Ca > K). Low bioaccumulation factor values (BAF < 1) indicate limited element accumulation relative to total soil concentrations for all three species, which may be influenced by both reduced bioavailability in neutral-to-alkaline soils and potential physiological regulation. As the first data reported from this region, these findings establish an essential baseline for long-term ecological monitoring, soil–plant chemistry, conservation, and environmental risk assessment in the Fann Mountains’ juniper ecosystems. Full article

Carbonate jade has emerged as a recently recognized commercial variety in the Chinese gemstone market. Systematic gemological and mineralogical investigations on carbonate jade, however, remain very scarce. Three Xinjiang calcite-dominated jade samples were investigated by using Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, ultraviolet-visible (UV-Vis) absorption spectroscopy, microbeam X-ray fluorescence (Micro-XRF) spectrometry, trace element analysis, in situ U-Pb dating, and C-O isotope analysis. The orange-red color originates from staining by hematite and magnetite inclusions, while the green color is produced by d-d electronic transitions of lattice-bound Fe³⁺ and Mn²⁺. The provenance comparison reveals systematic differences in trace element compositions between the Xinjiang carbonate jade and Pakistani Lvwen stone: the Xinjiang samples are characterized by extremely low Cu and Sr contents, whereas the Pakistani Lvwen stone has high Cu, Mn and Sr contents, and low Fe content. The U-Pb age obtained for the Xinjiang carbonate jade sample coincides with a Late Cretaceous rapid cooling event. Enriched light rare earth element (LREE) and C-O isotope (δ¹³C_V-PDB = −1.19–2.21‰, δ¹⁸O_V-SMOW = 15.00–20.01‰) signatures indicate that the carbonate-precipitating fluids were derived from marine carbonate wall rocks. These findings provide new mineralogical and geochemical constraints on the coloration mechanism, provenance, and fluid evolution of carbonate jade from Xinjiang. Full article

Understanding soil nutrients and stoichiometry across land-use types is essential for semiarid ecosystem management. We selected 130 sampling sites across four land-use types (dryland, paddy field, grassland, and forestland) in the Western Songnen Plain of China. We measured soil pH, nutrients (SOC, TN, TP, TK, and TS), trace elements (Mn, Zn, Cu, F, Se, and Cl), and oxides (MgO, CaO, Fe₂O₃, SiO₂, and TiO₂). One-way analysis of variance (ANOVA), Pearson correlation analysis, and redundancy analysis (RDA) were used to assess nutrient concentrations, stoichiometric ratios, and their environmental drivers. Our results showed that soils were generally alkaline, with the highest pH in grassland. Dryland had significantly higher SOC (12.47 g/kg), TN (1.05 g/kg), and TP (0.22 g/kg) than grassland (9.58, 0.79, and 0.19 g/kg, respectively). Forestland had the highest TK (23.18 g/kg). Most total nutrient concentrations were positively correlated with trace-element concentrations, except for TK. The C:N of paddy field (12.38) was significantly lower than those of grassland (14.24) and forestland (14.42), while both N:P (10.92) and N:K (0.13) were significantly higher than those in grassland (8.63, 0.11). The P:K of dryland (0.0137) was significantly higher than those in grassland (0.0108) and forestland soils (0.0106). RDA identified SOC and TP as common major factors associated with variation in nutrient stoichiometry, explaining 96.1%, 34.8%, 94.1%, and 93.2% of the variation in dryland, paddy field, grassland, and forestland, respectively. In addition, trace elements and oxides also explained the variation to varying degrees. This study provides a basis for sustainable land-use management in semiarid regions. Full article

The design of biomass-derived polymer electrolytes with integrated multifunctionality represents a key strategy for sustainable energy storage devices. Here, we report a fully biomass-derived dual-network hydrogel electrolyte fabricated by combining Pectin (PC) and Chitosan (CTS), two naturally abundant polysaccharides. The Pectin/Chitosan dual-network hydrogel electrolyte (PC/CTS) forms a robust physically crosslinked network through electrostatic interactions between the carboxyl groups of PC and the amino groups of CTS, reinforced by dense hydrogen bonding and amide crosslinks, yielding a tensile strength of 77.76 MPa. The abundant polar functional groups of the dual polymer network serve a synergistic dual function: the amino groups of CTS preferentially adsorb onto the zinc anode surface (adsorption energy: −1.24 eV), forming a dynamic protective interphase, while the carboxyl groups of PC coordinate with Zn²⁺ (binding energy: −0.86 eV), reconstituting the solvation sheath and guiding uniform ion flux. This anchorage-capture mechanism, enabled by the molecular design of the polymer network, effectively suppresses dendrite growth, hydrogen evolution, and parasitic side reactions. Consequently, the PC/CTS electrolyte enables stable Zn//Zn cycling for 3350 h, 99.5% average Coulombic efficiency (CE) over 780 Zn//Cu cycles (at 5 mA cm⁻² and 1 mAh cm⁻²), and 63.8% capacity retention after 500 cycles in Zn//MnO₂ full cells. This work demonstrates that rational engineering of natural polymer networks can simultaneously address electrode stability challenges in aqueous batteries, offering a sustainable materials platform for next-generation energy storage devices. Full article

Growing interest in underutilized plant resources has increased the need for comprehensive characterization of their elemental composition. This study investigated the elemental composition of Adansonia digitata L. bark collected from two ecologically distinct regions of Sudan and compared elemental distributions among three bark sample forms: whole, cryogenically ground bark (Bark-N), mechanically separated powder (Bark-P), and fibre fraction (Bark-F). Following HNO₃–H₂O₂ wet digestion, elemental concentrations were determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Generalized linear mixed-effects models revealed significant differences in regional and bark sample forms for several essential macroelements, essential trace elements, and other naturally occurring elements. Samples from the Blue Nile region contained higher concentrations of K, P, Fe, Cu, Co, and Mo, whereas bark from North Kordofan showed higher Mg, Na, Mn, Zn, Ba, and Sr concentrations. Distinct elemental profiles were also observed among the three bark sample forms. Selected potentially toxic elements (Pb, Cd, Cr, and As) were detected at low concentrations, providing baseline data for preliminary elemental safety screening. In general, this study provides one of the first comprehensive elemental characterizations of Sudanese baobab bark and establishes a reference dataset for future compositional, pharmaceutical, and industrial research. Full article

The article presents the results of the development of multicomponent adsorption materials based on industrial waste sludge from the water treatment plant of a thermal power plant. Activation of the sludge at 1000 °C makes it possible to obtain a porous matrix. It has been experimentally established that compositions with 50% activated sludge content in combination with oxides of Zn, Fe, Mn, Cu and NaOH have an optimal sorption capacity with respect to hydrogen sulfide. Kinetic studies have shown that the optimal contact time of the adsorbent with the adsorbate is 15–20 min, and the operating temperature should not exceed 300 K. The calculated thermodynamic parameters confirm the exothermic chemical mechanism of sorption. The materials have the ability to regenerate and display a color change upon contact with hydrogen sulfide. With respect to mercaptan sulfur, the maximum capacity was achieved for the sorption composition with 74.7% ZnO content. The logarithmic dependence of the mercaptan sulfur capacity on the percentage of zinc oxide in the composition has also been established. The environmental significance of the work lies in the utilization of large-tonnage waste and the absence of liquid effluents during regeneration. The proposed materials show promise as potentially cost-effective alternatives for gas purification, though comprehensive economic analysis remains the subject of future work. Full article

The development of efficient visible-light-driven semiconductor photocatalysts is essential for scalable and sustainable green hydrogen production. Among ternary metal oxides, MV₂O₆ (M = Zn, Ni, Cu, Mn, Co, etc.) metavanadates have attracted considerable interest because of their narrow band gaps (~1.8–2.5 eV), strong visible-light absorption, and unique edge-sharing VO₆ octahedral framework that promotes charge separation. This review summarizes recent advances in the design, synthesis, and electronic engineering of MV₂O₆-based photocatalysts for solar water splitting. Since direct particulate overall water splitting has only been demonstrated for MnV₂O₆, whereas ZnV₂O₆, NiV₂O₆, and CuV₂O₆ have mainly been investigated as photoelectrodes, both particulate photocatalytic and photoelectrochemical (PEC) systems are critically examined. The review clearly distinguishes these two configurations, highlighting how PEC studies provide valuable insights into charge transport, interfacial processes, and reaction kinetics while recognizing the additional challenges associated with suspension-based photocatalysis. Fundamental crystal structures, electronic band alignments, and charge-transfer characteristics of MV₂O₆ compounds are discussed, followed by recent advances in synthesis strategies, including hydrothermal, sol–gel, and deep eutectic solvent (DES)-assisted methods, together with morphology and defect engineering. Particular attention is given to oxygen-vacancy formation and its influence on visible-light absorption and charge separation. Modification strategies, including elemental doping, cocatalyst loading, and the construction of Z-scheme and step-scheme (S-scheme) heterojunctions, are critically evaluated for improving photocatalytic efficiency. Finally, the review discusses the key challenges that limit practical applications, including unfavorable band-edge positions, rapid carrier recombination, sluggish surface reaction kinetics, photostability, and the need to establish composition–structure–activity relationships. Future perspectives emphasize rational materials design through advanced characterization, theoretical calculations, and scalable synthesis approaches to accelerate the development of efficient MV₂O₆ photocatalysts for solar-driven hydrogen production. Full article

The shrinking of glaciers is drastically transforming headwater catchments, exposing new land surfaces and forming new water bodies, characterized by marked environmental gradients and the activation of potential geochemical hazards. The aim of this study was to characterize and compare the geochemical patterns of soil and water in areas deglaciated between 1970/1984 and 2025 within the Llaca and Gueshgue valleys of the Cordillera Blanca, Peru. Systematic soil and water sampling was conducted, and data were analyzed using descriptive statistics and multivariate techniques. The analyses revealed a clear and statistically significant geochemical differentiation between the two areas (p ≤ 0.05). Gueshgue was identified as a system in transition, exhibiting geochemical signatures of acid rock drainage (ARD), with loamy soils rich in Fe and Al, and acidic waters featuring high redox potential and elevated concentrations of SO₄²⁻, EC, Co, Cu, Mn and Mg. In contrast, Llaca exhibited greater stability, with neutral waters and sandy soils dominated by silicate weathering signatures (SiO₂) and trace elements (Al, Li, Ba, K, and Ti). These findings indicate that the impact of glacier retreat on proglacial ecosystems is heterogeneous; identifying these geochemical patterns is fundamental to establishing baseline monitoring and guiding the sustainable management of these climate-change-sensitive ecosystems. Full article

Manganese is a raw material of increasing strategic importance owing not only to its fundamental role in steel production but also to its use in battery technologies, chemical processes, environmental applications, and advanced industrial fields. With the ongoing energy transition, the growing demand for battery-grade manganese has made it increasingly important to reassess the geological, mineralogical, and geochemical characteristics of manganese occurrences that are known from limited data. In this study, the manganese mineralization observed in the Kulu–Kozanlı area of Central Anatolia was investigated using field observations, ore microscopy, XRD, SEM–EDS, major oxide and trace element geochemistry, and spatial data based on sampling locations. Major oxide and trace element data indicate that manganese enrichment is not homogeneous and is concentrated in specific zones. The results of Spearman correlation, PCA, HCA, and factor analysis reveal a clear opposition between MnO and SiO₂, whereas MnO tends to increase together with Cu, Ba, V, Ga, and Sr. XRD, SEM–EDS, and ore microscopy findings show that the mineralization is mainly represented by a Mn oxide/oxyhydroxide assemblage composed of manganite and pyrolusite, with local braunite. When all findings are evaluated together, the Kulu manganese mineralization is interpreted as a lithologically heterogeneous Mn mineralization associated with radiolarite/chert and carbonate–cherty levels within the Dereköy ophiolitic mélange and consistent with hydrothermal influence. Full article

Odorous gases such as hydrogen sulfide (H₂S) and dimethyl disulfide (DMDS) pose significant risks to human health and environmental quality. Non-thermal plasma (NTP) technology offers an effective alternative for odor treatment, but challenges remain regarding byproduct formation (e.g., ozone) and energy efficiency. In this study, a post-plasma catalysis (PPC) system combining a wire cylinder pulsed corona discharge reactor with a CuO/MnO₂-C ozone decomposition catalyst was employed to remove single and binary components of H₂S and DMDS. The effects of specific input energy (SIE), inlet concentration (C_in), and catalyst on removal efficiency, energy yield, and ozone emission were systematically investigated. A novel parameter, the ozone demand factor (Df), was defined to quantify the relationship between ozone consumption and pollutant removal. The results show that for single-component removal, regulating SIE/Cin within specific ranges (0.22–0.25 for H₂S and ~0.72 for DMDS) enables simultaneous low outlet concentrations of both pollutants and ozone. For binary H₂S-DMDS mixtures, ln(Df) exhibits a strong linear positive correlation with SIE/Σ(C_in) (R² = 0.968), and controlling SIE/Σ(C_in) at 0.28 yields ln(Df) ≈ 4, ensuring outlet H₂S < 5.0 ppm, DMDS < 3.0 ppm, and ozone < 5.0 ppm. This study demonstrates that the ozone demand factor serves as a critical control parameter for optimizing PPC systems, providing a practical tool for balancing pollutant removal and ozone emission in industrial odor treatment applications. Full article

Acidic wastewater generated during sulfuric acid leaching of reduced tionite within the EUROTITAN process was treated using three low-cost adsorbents: fly ash, bentonite, and red mud slag. Tionite is a solid residue originating from the sulfate route of TiO₂ production, whereas the investigated wastewater is a secondary acidic stream produced during hydrometallurgical treatment of reduced tionite. The initial wastewater was characterized by low pH and elevated concentrations of Fe, Al, Ti, B, Cu, Mn, Pb, Cr, and Li. Batch adsorption experiments were carried out by varying contact time from 4 to 24 h and adsorbent dosage from 5 to 15 g/L. The results showed distinct selectivity depending on adsorbent type and solution chemistry. Bentonite exhibited the most stable performance, achieving nearly complete removal of Pb, Cu, B, and Li, while Fe and Al were only partially removed and Ti removal remained limited. Fly ash showed high affinity toward Pb and Cu, but its performance was strongly affected by dosage and contact time. Red mud slag demonstrated excellent Pb removal, high Cu removal, and time- and dosage-dependent Ti removal, although partial dissolution of Fe- and Al-bearing phases occurred under strongly acidic conditions. Overall, the results confirm that industrial by-products and natural clay materials can contribute to partial purification of acidic metallurgical wastewater, while additional neutralization or polishing steps are required for complete treatment. Full article

Multicomponent ferrite oxides with mixed valence states and tunable oxygen-defect chemistry are promising active materials for low-power memristive synapses. In this work, Ag/Ni_0.3Cu_0.2Zn_0.5Co_0.005Mn_0.005Fe_1.99O/Ag memristors were fabricated by pulsed laser deposition, and the effects of post-deposition annealing at 700–900 °C on film structure, chemical states, magnetic behavior, resistive switching, and synaptic performance were investigated. The film annealed at 800 °C exhibited a dense surface morphology, improved crystallinity, and uniform elemental distribution. X-ray photoelectron spectroscopy confirmed the coexistence of Fe²⁺/Fe³⁺ states and oxygen-related defect components, indicating the presence of oxygen vacancies. Room-temperature magnetic hysteresis measurements revealed ferrite-type magnetic behavior in the annealed films, with the 800-annealed sample showing a relatively well-defined normalized hysteresis response. The optimized device exhibited representative bipolar resistive switching within ±0.5 V, distinguishable high- and low-resistance states, Ohmic conduction in the low-resistance state, and Schottky-emission-dominated transport in the high-resistance state. These results suggest that reversible oxygen-vacancy migration and interfacial barrier modulation govern the switching process. The device showed preliminary synaptic-like transient current responses. Further systematic reliability and conductance-modulation measurements are still required to fully evaluate endurance, reproducibility, and synaptic weight-update behavior. This study demonstrates that annealing-controlled multicomponent ferrite oxides offer a feasible route for energy-efficient memristive synaptic devices. Full article

AMn₇O₁₂ perovskites (with A = divalent elements) show complex structural and magnetic transitions including incommensurate orbital density waves and coupled/decoupled modulated spin helicity originating from charge-ordered Mn³⁺/Mn⁴⁺ cations with the 3:1 ratio at the B perovskite sites and unusual apically compressed Jahn–Teller distortions of MnO₆ octahedra. The same Mn³⁺:Mn⁴⁺ ratio can be achieved in RCuMn₆O₁₂ compositions, where R is a trivalent rare-earth cation. Therefore, the comparison in behavior of AMn₇O₁₂ and RCuMn₆O₁₂ is of interest. In this work, the A-site-ordered quadruple perovskite NdCuMn₆O₁₂ was prepared by a high-pressure high-temperature method. Its structural properties were investigated by synchrotron powder X-ray diffraction between 100 K and 350 K and laboratory powder X-ray diffraction between 5 K and 300 K. It shows a first-order structural phase transition from Im-3 symmetry (at high temperatures) to R-3 symmetry near 292 K. The structural transition is accompanied by charge (Mn³⁺/Mn⁴⁺) and unusual orbital (on the Jahn–Teller active Mn³⁺ cations located in MnO₆ octahedra) orders. However, no additional structural/orbital modulations were found at lower temperatures in comparison with AMn₇O₁₂. Magnetic properties were investigated by temperature- and field-dependent magnetization and specific heat measurements, where a ferrimagnetic transition was found near 120 K. In addition, low-temperature magnetic anomalies were observed near 20 K, probably originating from the Nd sublattice. Full article

Metal oxide nanoparticles serve as crucial drivers in modern biomedical, catalytic, environmental, and energy technologies due to their high surface-to-volume ratios and quantum confinement properties. Traditional chemical and physical synthesis methods remain limited by significant energy footprints, high costs, and the use of hazardous reagents. To address these challenges, bioinspired (“green”) synthesis has emerged as a sustainable paradigm that employs biological systems as nature nanofactories. This critical review provides a provides a comprehensive and systematic analysis of the green synthesis of major metal oxide systems (ZnO, TiO₂, Fe₃O₄/Fe₂O₃, CuO, Co₃O₄, CeO_2, and MnO₂) using diverse biological templates, including plant extracts, bacteria, fungi, algae, and biopolymers. Moving beyond simple descriptive summaries, we critically evaluate the foundational electron-transfer and nucleation mechanism, systematically correlate processing parameters with physical outcomes, and offer a rigorous comparative analysis across different biological kingdoms. Finally, we directly address the underlying challenges facing the field: reproducibility bottlenecks, scalability limits, environmental safety variations, and regulatory hurdles necessary for industrial translation. Full article

A novel sodium-oxide-fluxed slag is applied in the aluminothermic reduction of manganese ore. The slag’s high Al₂O₃ solubility facilitates the recycling of Al₂O₃ through hydrometallurgical processes, where NaAlO₂ serves as a water-leachable compound. Aluminothermic reduction is gaining renewed interest as an alternative processing route for the circular economy. In addition, CO₂ emissions in aluminium production via the electrochemical Hall–Héroult process can be reduced if the process electricity is sourced from non-fossil fuels. The unique Na₂O-fluxed MnO₂ ore formulation includes a small quantity of carbon reductant to ensure rapid pre-reduction to MnO. This approach negates the need for a pre-roasting step. Feed mixture variations with different collector metal additions (Si, Cr, Cu) were made to improve alloy–slag separation efficiency. The collector metals may influence the chemistry of the slag. This work compares the phase chemistry of slags formed during aluminothermic reduction to equilibrium phase chemistries calculated for the Na₂O-SiO₂-Al₂O₃-MnO-CaO system. The slag phase morphology consists of distinct alumina-rich strands (1.5% to 2.1%) embedded within a Na₂O-SiO₂-Al₂O₃-MnO-CaO glass matrix. The alumina-rich strands appear molten, indicating that the processing temperatures were higher than their liquidus temperatures (1537 °C to 1655 °C), as high as 1921 °C and 2053 °C. These findings contribute to sustainable practices in the circular economy through the production of low-carbon ferro-manganese complex alloys. Full article