Search Results (20,296)

This study examined the effects of zinc–iron (Zn–Fe) biofortified alfalfa on mineral deposition, growth performance, feed efficiency, and selected meat-quality traits in guinea pigs (Cavia porcellus). Four alfalfa cultivars (Cuf101, Moapa69, California55, and Yaragua) were cultivated under two fertilization levels (0–0 and 2–2 kg ha⁻¹ Zn–Fe). Biofortification increased forage Zn concentrations from 26.8 to 36.4 mg kg⁻¹ to as high as 325.8 mg kg⁻¹, and Fe concentrations from 139.7 to 425.0 mg kg⁻¹ to 450.1 mg kg⁻¹. A total of 48 weaned guinea pigs (initial body weight 0.30 ± 0.01 kg) were allocated to a randomized multi-factorial feeding trial. Growth performance, feed intake, feed conversion ratio (FCR), and tissue mineral concentrations were evaluated over a 35–50 day period and analyzed using a multi-factorial ANOVA within a General Linear Model framework. Dietary biofortification resulted in a significant improvement in feed efficiency, with FCR decreasing from 6.3 in the control diet to 5.8 in the enriched diet, and the lowest FCR was observed in animals fed the California55 cultivar (5.1). No statistically significant sex effect was detected for live weight gain, although males showed higher total weight gain (248.7 g) than females (187.8 g). Tissue Zn (≈20.7 mg kg⁻¹) and Fe (≈10.2 mg kg⁻¹) concentrations in meat were only marginally affected by diet, suggesting strong physiological regulation of mineral deposition. Multivariate analyses indicated that the enriched diet produced more homogeneous meat-quality profiles and reduced inter-animal variability. Overall, Zn–Fe biofortified alfalfa improved feed efficiency without compromising growth performance or meat quality, indicating potential relevance for smallholder guinea pig production systems. However, given the limited sample size per factorial cell, the findings should be interpreted with caution and considered exploratory, warranting confirmation in larger, adequately powered studies. Full article

Aligned with circular bioeconomy principles, which aim to establish closed-loop systems that maximize resource utilization and renewal while minimizing waste, this study developed and characterized innovative catalysts derived from waste almond shells. These shells were carbonized and functionalized to create active surfaces containing Lewis and Brønsted acid sites. Modification was achieved through treatment with ZnCl₂ to introduce Lewis acid (LA) sites and with sulfuric acid to generate Brønsted acid (BA) sites. Detailed instrumental analyses enabled assessment of catalyst morphology, textural parameters, and surface functional groups. A physical mixture of the two catalysts was used to convert glucose into 5-hydroxymethylfurfural (HMF), yielding a maximum HMF yield of 76.8%. The results indicate that the collaborative action of Lewis and Brønsted acid sites, along with oxygen-containing surface groups, contributes to catalyst efficiency. These insights facilitate targeted catalyst optimization by adjusting surface texture and functional groups. Full article

The widespread occurrence of pharmaceutical contaminants in aquatic environments poses significant risks to ecosystems and public health, necessitating the development of efficient and sustainable treatment technologies. Herein, a visible-light (VL)–active zinc single-atom catalyst supported on biochar (SAZn@BC) was synthesized via pyrolysis and applied for the degradation of ibuprofen (IBP), sulfamethoxazole (SMX), trimethoprim (TMP), and carbamazepine (CBZ) in water. Structural characterization confirmed the presence of g-C₃N₄ domains, abundant oxygen-containing functional groups, and atomically dispersed Zn sites with a Zn–N₄ coordination environment. Under VL irradiation, SAZn@BC achieved degradation efficiencies of 43.9%, 64.4%, and 61.9% for IBP, SMX, and TMP, respectively, within 30 min, while CBZ exhibited limited removal. Mechanistic investigations combining quenching experiments, electrochemical analyses, and X-ray photoelectron spectroscopy revealed that superoxide and hydroperoxyl radicals were the dominant reactive oxygen species, with hydroxyl radicals and singlet oxygen contributing to a lesser extent. In addition, a nonradical pathway involving direct interfacial electron transfer between oxygen functional groups on the biochar support and pharmaceutical molecules played a critical role, mediated by single-atom Zn sites and enhanced under VL irradiation. These findings demonstrate that SAZn@BC enables synergistic radical and nonradical pathways for pharmaceutical degradation and represents a promising strategy for water treatment applications. Full article

Metal ions exemplify one of the most harmful and environmentally detrimental contaminants of water systems. This work describes the creation of an innovative chelated carbon-doped nickel and titanium oxide (C-NiTiO₂) hybrid as an adsorbent for the effective elimination of metal ions. The dominance of the TiO₂ anatase phase with a ≈ 61 nm crystallite size was verified by XRD and Raman investigation. Morphology investigations exposed polygonal nanoparticles consisting of Ti, C, Ni, and O. The nanostructure exhibited a surface area of 17 m²·g⁻¹, a pore diameter of ≈1.5 nm, and a pore volume of 0.0315 cm³·g⁻¹. The nanostructure was evaluated for the elimination of Zn (II) ions from an aqueous solution. The metal ion adsorption onto the hybrid nanomaterial was described and comprehended using adsorption kinetics and equilibrium models. The adsorption data matched well with the pseudo-second-order kinetics and Langmuir adsorption models, indicating a monolayer chemisorption mechanism and achieving a maximum Zn (II) ion elimination of 369 mg·g⁻¹. Mechanistic investigation indicated film diffusion-controlled adsorption through inner-sphere complexation. The nanosorbent could be regenerated and reused for four rounds without appreciable activity loss, thus demonstrating its potential for water cleanup applications. Full article

Copper (Cu) and zinc (Zn) are critical for global high-tech industries and national economic security. With high-grade mineral depletion, recycling valuable metals from iron ore tailings has become a sustainable solution. A Peruvian mining company’s iron ore tailing reprocessing faces a severe challenge: surging lead (Pb) content due to increased excavation depth has rendered the original Cu-Zn bulk flotation flowsheet ineffective, causing excessive impurities in concentrates. This study first characterized the occurrence states of Cu, Pb, and Zn via multi-analytical techniques. A novel Cu-Pb-Zn iso-flotation process with step-by-step depression, coupled with optimized reagents, was proposed. It abandons initial CuSO₄ activation to reduce separation difficulty and uses targeted depressants for efficient impurity removal. Closed-circuit tests yielded a Cu concentrate (26.57% grade, 56.08% recovery) with Pb/Zn contents reduced to 2.97%/9.80%, and a Zn concentrate (44.95% grade, 75.56% recovery) with Cu/Pb controlled at 1.15%/8.31%. Experimental results demonstrate that this new flowsheet effectively mitigates the impact of high Pb content, restoring production efficiencies and offering a valuable precedent for industrial process modification. Full article

In November 2023, surface sediments were collected at 46 sites around the main islands of the Zhoushan Archipelago (Dinghai, Daishan, Qushan, and Shengsi) in the East China Sea. The concentrations of Cu, Zn, Cr, Pb, Cd, Hg, and As were determined, together with sediment TOC and Eh. Pollution and ecological risks were evaluated using the single-factor index (Pi), Nemerow pollution index (PN), and Hakanson’s potential ecological risk index (RI). Source apportionment was investigated using FA–PC and EPA PMF 5.0. Mean concentrations (mg/kg) were Zn 77.58, Cr 70.08, Cu 28.44, Pb 18.92, As 9.40, Cd 0.09, and Hg 0.073, with higher levels generally observed near Dinghai, Daishan, and Shengsi. The overall risk was low, whereas Cd and Hg contributed disproportionately to RI. FA–PC suggested two major source groups, and PMF resolved three factors related to (i) agriculture/aquaculture (As), (ii) industrial and domestic effluents (Hg), and (iii) port and ship-related activities (Cd, Cu, Cr, Pb, Zn). The results support targeted management focusing on Cd, Hg, Cu, and As in identified hotspots. Full article

The application of forest byproducts to cropland provides significant benefits, mitigating soil degradation, supplying essential nutrients, and increasing yields. Their impact is well known in the first years, but few studies have examined the effects several years after an application. A field study was initiated in Québec, QC, Canada, to assess the effects of wood ash (10 and 20 Mg dry wt. ha⁻¹), pine biochar (10 Mg dry wt. ha⁻¹), paper mill sludge (PS) (12 Mg dry wt. ha⁻¹), and a combination of wood ash and PS, relative to an untreated control and a mineral treatment, on crop yield and soil properties three to seven years after application in a temperate circumneutral loamy soil. The site was cropped to a maize (Zea mays L.)–soybean [Glycine max (L.) Merr.]–spring wheat (Triticum aestivum L.) rotation. Each crop received supplemental N and P from mineral fertilizers, when needed, according to local agronomic recommendations. Applying wood ash increased wheat yield by 0.25–0.44 Mg ha⁻¹ three years after the addition, but no effect was detected in other cases and for the other amendments. Wood ash also resulted in the largest increases (p < 0.05) in soil pH and Mehlich-3 P, K, Ca, Mg, Zn, and Cd, alone or in combination with PS. Pine biochar promoted soil C sequestration after seven years, but did not affect other soil properties owing to its high stability and low nutrient content. This study revealed that wood ash was more advantageous than pine biochar for improving soil quality and crop productivity. Full article

Groundwater, a critical resource for regional water security and public health, faces escalating threats from heavy metal contamination—a pressing environmental challenge worldwide. This study focuses on the central-south Hunan region of China, a mineral-rich, densely populated area characterized predominantly by non-point-source pollution, aiming to systematically unravel the spatial patterns, source contributions, and associated health risks of heavy metals in local groundwater. Based on 717 spring and well water samples collected in 2024, we determined pH and seven heavy metals (As, Cd, Pb, Zn, Fe, Mn, and Tl). By integrating hydrogeological zoning, lithology, topography, and river networks, the study area was divided into 11 assessment units, clearly revealing the spatial heterogeneity of heavy metals. The results demonstrate that exceedances of Cd, Pb, and Zn were sporadic and point-source-influenced, whereas As, Fe, Mn, and Tl showed regional exceedance patterns (e.g., Mn exceeded the standard in 9.76% of samples), identifying them as priority control elements. The spatial distribution of heavy metals was governed the synergistic effects of lithology, water–rock interactions, and hydrological structure, showing a distinct “acidic in the northeast, alkaline in the southwest” pH gradient. Combined application of the APCS-MLR and PMF models resolved five principal pollution sources: an acid-reducing-environment-driven release source (contributing 76.1% of Fe and 58.3% of Pb); a geogenic–anthropogenic composite source (contributing 81.0% of Tl and 62.4% of Cd); a human-perturbation-triggered natural Mn release source (contributing 94.8% of Mn); an agricultural-activity-related input source (contributing 60.1% of Zn); and a primary geological source (contributing 89.9% of As). Monte Carlo simulation-based health risk assessment indicated that the average hazard index (HI) and total carcinogenic risk (TCR) for all heavy metals were below acceptable thresholds, suggesting generally manageable risk. However, As was the dominant contributor to both non-carcinogenic and carcinogenic risks, with its carcinogenic risk exceeding the threshold in up to 3.84% of the simulated adult exposures under extreme scenarios. Sensitivity analysis identified exposure duration (ED) as the most influential parameter governing risk outcomes. In conclusion, we recommend implementing spatially differentiated management strategies: prioritizing As control in red-bed and granite–metamorphic zones; enhancing Tl monitoring in the northern and northeastern granite-rich areas, particularly downstream of the Mishui River; and regulating land use in brick-factory-dense riparian zones to mitigate disturbance-induced Mn release—for instance, through the enforcement of setback requirements and targeted groundwater monitoring programs. This study provides a scientific foundation for the sustainable management and safety assurance of groundwater resources in regions with similar geological and anthropogenic settings. Full article

This paper presents a comprehensive characterization of bottom ash generated during biomass combustion in fluidized boilers, with a focus on its potential use in a circular economy. Two biomass bottom ash samples (BBA 1 and BBA 2) from commercial combined heat and power plants were tested. The scope of this study included the determination of chemical composition, phase composition, and leachability testing of selected impurities. The results showed that the bottom ashes tested are calcium silicate materials with varying proportions of calcium phases (anhydrite, portlandite, and calcite) and silica phases (quartz), depending on the type of biomass and combustion technology. Thermal analysis confirmed the presence of characteristic dehydration, decarbonation, and polymorphic transformations of quartz, with a low organic content. Leachability tests showed low mobility of most trace elements and heavy metals, with increased solubility of sulfates, chlorides, and alkali ions, typical for fluidized ash. The concentrations of As, Cd, Cr, Cu, Pb, Zn, and Hg in the eluates were low or below the limit of quantification, indicating the favorable chemical stability of the tested waste. The results obtained suggest that bottom ashes from biomass combustion in fluidized boilers may be a promising secondary raw material for engineering applications, especially in binding materials and bonded layers, and potentially also in selected agricultural applications, provided that the contents of sulfates, chlorides, and pH are controlled. Full article

The Sichuan–Yunnan–Guizhou Pb-Zn metallogenic belt (SYG metallogenic belt), a crucial metallogenic unit on the southwestern margin of the Yangtze Block, is a key part of the South China low-temperature metallogenic domain. The incorporation mechanisms and distribution of trace elements (e.g., Ge, Ga, Cd) widely enriched in Pb-Zn sulfides throughout this region remain poorly understood. This study investigates main-ore-stage sulfides (sphalerite and pyrite) from the Maoping Pb-Zn deposit using in situ laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses and mapping to systematically elucidate the partitioning and occurrence of these trace elements. The key findings are as follows: (1) Sulfides show distinct elemental partitioning: sphalerite preferentially concentrates Cd, Ag, Ge, Ga, and Se, whereas pyrite is significantly enriched in Mn, Ni, As, and Co. (2) Sphalerite is the primary host for many trace elements. Cadmium, Ge, Mn, Cu, and Ag mainly enter the sphalerite lattice by substituting for Zn²⁺. Coupled substitution mechanisms, such as Zn²⁺ ↔ Cd²⁺, 2Zn²⁺ ↔ Ge²⁺ + Cu²⁺, and 2Zn²⁺ ↔ Ga³⁺ + Cu⁺, facilitate the incorporation of Ge and Ga. (3) The sphalerite exhibits a trace element assemblage of high Cd-Ge and low Fe-Mn, which is geochemically similar to typical Mississippi Valley-type (MVT) deposits and differs significantly from sedimentary exhalative (SEDEX) and magmatic–hydrothermal deposits, indicating a medium- to low-temperature metallogenic environment. Based on these geochemical signatures and epigenetic textures, we confirm that the Maoping Pb-Zn deposit exhibits similarities with MVT deposits. Nevertheless, distinct differences in the tectonic setting and metal grades suggest it is a unique SYG-type Pb-Zn deposit. Full article

This study investigates the as-cast Mg-8Gd-1Y-2Sm-1.2Zn-0.5Mn (wt.%) alloy with high rare-earth content. Solution treatments were conducted at 480 °C, 520 °C, and 560 °C for 6–10 h. Microstructure and mechanical properties were characterized using OM, XRD, SEM-EDS, and compression testing. The as-cast alloy shows a dendritic structure with continuous grain-boundary phases (Mg₅RE, W, and LPSO), exhibiting a compressive yield strength of 145 MPa, ultimate strength of 238 MPa, and fracture strain of 12.66%. Solution temperature has a critical influence on phase dissolution and grain refinement. Notably, the overall plasticity of the material did not show a significant dependence on the specific solution temperature or holding time within the studied range. Treatment at 520 °C produces the most balanced microstructure: clear grain boundaries, extensive phase dissolution, refined grains, and enhanced solid-solution strengthening. Specifically, 520 °C for 10 h results in the finest and most uniformly distributed residual phases, a homogeneous matrix, the highest compressive strength, and suitable conditions for subsequent aging, thus being identified as optimal. Fractography reveals a transition from quasi-cleavage in the as-cast state toward enhanced ductility after solution treatment. However, small cleavage facets after 10 h are attributed to stress concentrations from rare-earth-rich regions and reduced deformation compatibility due to retained LPSO phases. Full article

Nitrate pollution in groundwater poses severe threats to ecosystems and human health, making the electrochemical nitrate reduction reaction (NO₃RR) a promising remediation technology. Conductive metal–organic frameworks (cMOFs) with π-d conjugation, dispersed active sites, and tunable structures are ideal candidates for electrocatalysis. Herein, we synthesized a series of cMOFs (M₃(HHTP)₂, M = Fe, Zn, Cu, Co, Ni) via conjugated coordination between hexahydroxytriphenylene (HHTP) ligands and metal ions and systematically investigated their NO₃RR performance. Electrochemical tests revealed that Fe₃(HHTP)₂ exhibits superior catalytic performance for nitrate reduction, achieving a high NH₃ selectivity of 99.5% and a yield rate of 676.4 mg·g_cat⁻¹·h⁻¹ at −1.0 V vs. RHE (reversible hydrogen electrode), along with excellent cyclic and structural stability. In situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy identified key intermediates (*NO₂, *NH₂OH) and proposed the reaction pathway: NO₃⁻ → *NO₃ → *NO₂ → *NO → *NOH → *NH₂OH → *NH₂ → *NH₃. DFT calculations revealed that Fe center exhibited a lower energy barrier for NO₃RR compared to other metal ions (Zn, Cu, Co, Ni). This study demonstrates the significant potential of Fe₃(HHTP)₂ for efficient NO₃RR and provides new insights into the structure-function relationship of cMOF-based electrocatalysts. Full article

Hard carbon is widely recognized as a viable anode candidate for sodium-ion batteries (SIBs) owing to its electrochemical advantages, yet simultaneously enhancing specific capacity and rate capability, arising from insufficient plateau capacity, remains a long-standing challenge. Herein, we present a strategy for fabricating ZnCl₂-modified hard carbon (HCMZ-X) using waste macadamia shells and ZnCl₂ as a multifunctional structural modifier through a facile high-temperature carbonization. This approach effectively expands the graphite interlayer spacing to 0.394 nm, reduces microcrystalline size, and induces abundant closed pores, synergistically improving sodium-ion storage kinetics within the hard carbon framework. Mechanistic investigations confirm an “adsorption-intercalation-filling” storage mechanism. Hence, the optimized HCMZ-3 delivers a high reversible capacity of 382.05 mAh g⁻¹ at 0.05 A g⁻¹, with the plateau region contributing approximately 70%, significantly outperforming that of unmodified hard carbon (262.64 mAh g⁻¹). Remarkably, it achieves stable rate performance, delivering 190 mAh g⁻¹ at 1 A g⁻¹, along with excellent cycling stability, retaining over 90% after 500 cycles. By rational pore-structure modulation rather than excessive surface activation, this cost-effective method utilizing agricultural waste and ZnCl₂ dual-functional modification partially alleviates the intrinsic energy-density limitation of hard carbon anodes, advancing the development of high-performance, eco-friendly anodes for scalable energy storage systems. Full article

Low-voltage primary batteries broadly power small electronics used in health, biomedical, and wearable applications. These devices are generally more sensitive to volumetric capacity than gravimetric capacity. The current state-of-the-art button battery is Zn-Ag₂O, where contributors that limit volumetric capacity include the incorporation of inactive materials in the electrode microstructure such as gelling agents, binders, and conductive additives. Herein, cathode materials of CuO and FeS₂ will be described for small form factor coin/button cells. When paired with Li metal anodes, the operating voltage is similar to Zn-Ag₂O. The key innovation is that they will be processed into all-active-material (AAM) electrode architectures, where the electrodes will comprise only electroactive materials and pores that are filled with electrolyte during cell fabrication. The AAM architecture significantly enhanced electroactive material volume utilization, and thus volumetric capacity. FeS₂ and CuO were processed into AAM electrodes under various processing conditions, and Li-FeS₂ and Li-CuO primary batteries were fabricated and evaluated. At the cell level, volumetric capacity of 1300 mAh cm⁻³ was achieved, and in a button cell form factor 395/927, nearly 100 mAh was delivered, which compares favorably with commercially available options, which typically range from 27 to 55 mAh. Full article

Phytoremediation is an eco-friendly and in situ solution for remediating heavy metal-contaminated soils, yet practical application requires timely and accurate effectiveness evaluation. However, conventional chemical analysis of plant parts and soils is labor-intensive, time-consuming and limited for large-scale monitoring. This study proposed a rapid sensing framework integrating laser-induced breakdown spectroscopy (LIBS) with deep transfer learning and spectral indices to assess phytoremediation effectiveness of Sedum alfredii (a Cd/Zn co-hyperaccumulator). LIBS spectra were collected from plant tissues and diverse soil matrices. To overcome strong matrix effects, fine-tuned convolutional neural networks were developed for simultaneous multi-matrix quantification, achieving high-accuracy prediction for Cd and Zn (R²_test > 0.99). These predicted concentrations enabled calculating conventional phytoremediation indicators like bioconcentration factor (BCF), translocation factor (TF), plant effective number (PEN), and removal efficiency (RE), yielding recovery rates near 100% for TF and PEN. Additionally, novel spectral indices (SIs)—directly derived from characteristic wavelength combinations—were constructed to bypass intermediate quantification. SIs significantly improved the direct evaluation of Zn removal and translocation. Finally, a decision-level fusion strategy combining concentration predictions and SIs enhanced Cd removal assessment accuracy. This study validates LIBS combined with intelligent algorithms as a rapid sensor tool for monitoring phytoremediation performance, facilitating sustainable environmental management. Full article