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25 pages, 749 KiB  
Review
Hemp-Based Meat Analogs: An Updated Review on Extraction Technologies, Nutritional Excellence, Functional Innovation, and Sustainable Processing Technologies
by Hassan Barakat and Thamer Aljutaily
Foods 2025, 14(16), 2835; https://doi.org/10.3390/foods14162835 - 15 Aug 2025
Abstract
The global transition toward plant-based diets has intensified the search for sustainable protein alternatives, positioning hemp-based meat analogs (HBMAs) as a promising solution due to their exceptional nutritional profile and environmental benefits. This comprehensive review critically examines hemp protein research, focusing on extraction [...] Read more.
The global transition toward plant-based diets has intensified the search for sustainable protein alternatives, positioning hemp-based meat analogs (HBMAs) as a promising solution due to their exceptional nutritional profile and environmental benefits. This comprehensive review critically examines hemp protein research, focusing on extraction technologies, nutritional excellence, functional innovation, and sustainable processing approaches for meat analog development. Hemp seeds contain 25–30% protein, primarily consisting of highly digestible edestin and albumin proteins that provide a complete amino acid profile comparable to soy and animal proteins. The protein exhibits superior digestibility (>88%) and generates bioactive peptides with demonstrated antioxidant, antihypertensive, and anti-inflammatory properties, offering significant health benefits beyond basic nutrition. Comparative analysis reveals that while alkaline extraction-isoelectric precipitation remains the industrial standard due to cost-effectiveness ($2.50–3.20 kg−1), enzymatic extraction and ultrasound-assisted methods deliver superior functional properties despite higher costs. Hemp protein demonstrates moderate solubility and good emulsifying properties, though its gelation capacity requires optimization through enzymatic hydrolysis, high-pressure processing, or strategic blending with complementary proteins. Processing innovations, particularly high-moisture extrusion combined with protein blending strategies, enable fibrous structures closely mimicking conventional meat texture. Hemp protein can replace up to 60% of soy protein in high-moisture meat analogs, with formulations incorporating wheat gluten or chickpea protein showing superior textural attributes. Despite advantages in nutritional density, sustainability, and functional versatility, HBMAs face challenges including sensory limitations, regulatory barriers, and production scaling requirements. Hemp cultivation demonstrates 40–50% lower carbon footprint and water usage compared with conventional protein sources. Future research directions emphasize techniques and action processes, developing novel protein modification techniques, and addressing consumer acceptance through improved sensory properties for successful market adoption. Full article
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18 pages, 5424 KiB  
Article
Preparation and Characterization of Highland Barley Distillers’ Grains Gliadin–Chitosan Nanoparticles and Composite Properties
by Qian Lv and Yiquan Zhang
Molecules 2025, 30(16), 3390; https://doi.org/10.3390/molecules30163390 - 15 Aug 2025
Viewed by 20
Abstract
In embedding systems, protein–polysaccharide complexes can be utilized as wall materials to improve the bioavailability and activity of bioactive substances during delivery. This study used the antisolvent precipitation method to manufacture gliadin from highland barley distillers’ grains (HBDGG)–chitosan (Cs) nanoparticles. Using a variety [...] Read more.
In embedding systems, protein–polysaccharide complexes can be utilized as wall materials to improve the bioavailability and activity of bioactive substances during delivery. This study used the antisolvent precipitation method to manufacture gliadin from highland barley distillers’ grains (HBDGG)–chitosan (Cs) nanoparticles. Using a variety of characterization techniques, the microstructure and interaction mechanism of HBDGG-Cs nanoparticles were examined, and their stability was assessed. In comparison to HBDGG, the results indicated that the addition of Cs enhanced the intensity of UV absorption and reduced the intensity of fluorescence. The content of α-helix dropped, while β-sheet, β-turn, and irregularly coiled content rose in the complexes. Hydrogen bonding, hydrophobic interactions, and electrostatic interactions were the primary forces that formed the nanoparticles. The contact force between HBDGG and Cs enhanced the stability of the nanoparticles. The particle size, polydispersity index (PDI), and zeta potential were 526.10 ± 11.78 nm, 0.20 ± 0.06, and 51.31 ± 0.66 mV, respectively, at a mass ratio of 1:1 between HBDGG and Cs. The nanoparticles exhibited good ionic, acid-base, and storage stability in addition to being widely distributed. This work offers a theoretical foundation for employing HBDGG-Cs nanoparticles to deliver bioactive components in food as well as a novel method for the comprehensive usage of HBDGG and Cs. Full article
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19 pages, 4405 KiB  
Article
Photodegradation of Pyridine in a Fluidized Bed Photocatalytic Reactor Using Pt-ZnO Supported on Al2O3 as a Catalyst
by Ruby Gines, Carlos Montalvo, Guadalupe Luna, Daniel Montalvo, Rosa M. Cerón, Julia G. Cerón, Sinuhe Ginés, Aracely García and Claudia A. Aguilar
Catalysts 2025, 15(8), 772; https://doi.org/10.3390/catal15080772 - 13 Aug 2025
Viewed by 253
Abstract
Pyridine is a recalcitrant organic compound present in industrial wastewater that causes severe effects on the environment and the health of living beings, as it is considered a toxic, mutagenic, teratogenic, and carcinogenic agent. Therefore, this research explored the efficacy of a zinc [...] Read more.
Pyridine is a recalcitrant organic compound present in industrial wastewater that causes severe effects on the environment and the health of living beings, as it is considered a toxic, mutagenic, teratogenic, and carcinogenic agent. Therefore, this research explored the efficacy of a zinc oxide catalyst, doped with platinum nanoparticles and supported alumina through the precipitation method, for the photocatalytic degradation of pyridine using a fluidized bed reactor. A Box–Behnken experimental design was used to analyze the effect of the pH (4–10), the pyridine concentration (20–300 ppm), and the amount of catalyst (20–100 g). The X-ray diffraction (XRD) characterization results confirmed the hexagonal structure of the zinc oxide and the successful incorporation of platinum. Scanning electron microscopy (SEM) revealed a nano-bar morphology upon catalyst doping, favoring the photocatalytic activity. Pyridine removal of 57.7% was achieved under the following conditions: a pH of 4, 160 ppm of pyridine, and 100 g of catalyst. The process followed a pseudo-first-order model, obtaining the reaction constant k1 = 1.943 × 10−3 min−1 and the adsorption constant k2 = 1.527 × 10−3 L/mg. The results showed high efficiency and stability of the catalyst in the fluidized bed reactor for pyridine degradation, especially under acidic conditions, representing a promising technological alternative for treating industrial wastewater contaminated with N-heterocycles such as pyridine. Full article
(This article belongs to the Special Issue Advances in Photocatalytic Degradation)
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14 pages, 1689 KiB  
Article
Effect of Sulfoaluminate Clinker Addition on Boron Removal During Water Softening
by Marco Tagliabue, Alessandra de Folly d’Auris, Andrea Pacini, Michela Bellettato, Gianluigi Marra, Sara Perucchini, Cinzia Mazzara, Emanuele Lagrotta and Marco Vocciante
Appl. Sci. 2025, 15(16), 8890; https://doi.org/10.3390/app15168890 - 12 Aug 2025
Viewed by 134
Abstract
Boron is frequently present in saline water (e.g., seawater, geothermal water, and hydrocarbon production water) due to the natural release of boric acid from minerals. While essential to life, excess boron is toxic, particularly to citrus plants, necessitating its regulation for safe water [...] Read more.
Boron is frequently present in saline water (e.g., seawater, geothermal water, and hydrocarbon production water) due to the natural release of boric acid from minerals. While essential to life, excess boron is toxic, particularly to citrus plants, necessitating its regulation for safe water use. Current boron removal methods, such as reverse osmosis, chelating resin adsorption, and magnesium-based precipitation softening, increase water treatment complexity and cost. Ettringite, (Ca6Al2(SO4)3(OH)12·26H2O), is a clay and an effective anion adsorbent. It is also a key hydration product of Portland cement. This study explores boron removal via precipitation softening using sulfoaluminate clinker as an ettringite precursor. Raw water, a first-stage reverse-osmosis permeate from an Italian oil-and-gas site, contained approximately 15.0 mg/L of boron. Optimal removal required sulfoaluminate clinker in excess with respect to the stoichiometric dose and 150 min of contact time. The preliminary results demonstrate the feasibility of this approach, offering a viable alternative to existing methods. Full article
(This article belongs to the Special Issue New Approaches to Water Treatment: Challenges and Trends, 2nd Edition)
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13 pages, 2696 KiB  
Article
Chemistry of Precipitation Acidity at Irkutsk, Russia
by Hiroshi Hara and Izumi Noguchi
Atmosphere 2025, 16(8), 959; https://doi.org/10.3390/atmos16080959 - 12 Aug 2025
Viewed by 196
Abstract
Precipitation pH at a Russin EANET site, Irkutsk, was discussed and explained from the viewpoint of acid–base chemical equilibrium theory. The datasets employed were the wet-only daily basis observations at a subarctic climate urban site from 1999 to 2020. A distinct seasonal variation [...] Read more.
Precipitation pH at a Russin EANET site, Irkutsk, was discussed and explained from the viewpoint of acid–base chemical equilibrium theory. The datasets employed were the wet-only daily basis observations at a subarctic climate urban site from 1999 to 2020. A distinct seasonal variation in pH was discovered for the monthly means over the entire period, from pH5.24 in July to pH6.66 in February, bracketing pH5.6, a criterion for acid rain. Monthly concentration variations in major ions, nss-SO42−, NO3, NH4+, and nss-Ca2+, divulged that nss-Ca2+ and nss-SO42− were predominant species and that nss-Ca2+ dominated nss-SO42− during winter months and vice versa in summer. Individual pHs were explored with the concentration difference between two ions, ([nss-SO42−] − [nss-Ca2+]), defined as D2, as well as two other differences in selected ion groups, D4 = ([nss-SO42−] + [NO3]) − ([NH4+] + [nss-Ca2+]) and D6 = ([nss-SO42−] + [NO3]) − ([NH4+] + [nss-Ca2+] + [nss-Mg2+] + [nss-K+]), to show some clear relationships with pH. The observed results were compared with theoretical calculations, Dn = [H+] − HPCO2Ka1/[H+], where n is 2, 4, or 6. The distribution of ΔpH (=pHcalc − pHobs) for D2 demonstrated the most reasonable pattern with a median of zero among the three Dns. These quantitative results conclude that the Irkutsk pH was controlled dominantly by sulfuric acid and calcium carbonate. Full article
(This article belongs to the Section Air Quality)
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23 pages, 4238 KiB  
Article
Tuning Nanofibrous Sensor Performance in Selective Detection of B-VOCs by MIP-NP Loading
by Antonella Macagnano, Fabricio Nicolas Molinari, Simone Serrecchia, Paolo Papa, Anna Rita Taddei and Fabrizio De Cesare
Nanomaterials 2025, 15(16), 1220; https://doi.org/10.3390/nano15161220 - 9 Aug 2025
Viewed by 300
Abstract
In this study, we investigate the effect of varying the loading of molecularly imprinted polymer nanoparticles (MIP-NPs) on the morphology and sensing performance of electrospun nanofibres for the selective detection of linalool, a representative plant-emitted monoterpene. The proposed strategy combines two synergistic technologies: [...] Read more.
In this study, we investigate the effect of varying the loading of molecularly imprinted polymer nanoparticles (MIP-NPs) on the morphology and sensing performance of electrospun nanofibres for the selective detection of linalool, a representative plant-emitted monoterpene. The proposed strategy combines two synergistic technologies: molecular imprinting, to introduce chemical selectivity, and electrospinning, to generate high-surface-area nanofibrous sensing layers with tuneable architecture. Linalool-imprinted MIP-NPs were synthesized via precipitation polymerization using methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA), yielding spherical particles with an average diameter of ~135 nm. These were embedded at increasing concentrations into a polyvinylpyrrolidone (PVP) matrix containing multi-walled carbon nanotubes (MWCNTs) and processed into nanofibrous mats by electrospinning. Atomic force microscopy (AFM) revealed that MIP content modulates fibre roughness and network morphology. Electrical sensing tests performed under different relative humidity (RH) conditions showed that elevated humidity (up to 60% RH) improves response stability by enhancing ion-mediated charge transport. The formulation with the highest MIP-NP loading exhibited the best performance, with a detection limit of 8 ppb (±1) and 84% selectivity toward linalool over structurally related terpenes (α-pinene and R-(+)-limonene). These results demonstrate a versatile sensing approach in which performance can be precisely tuned by adjusting MIP content, enabling the development of humidity-tolerant, selective VOC sensors for environmental and plant-related applications. Full article
(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)
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21 pages, 4126 KiB  
Article
A Glycerol Acetylation Study on a Tin Ferrite Nanocatalyst
by Rami Doukeh, Andreea-Cătălina Joe, Ion Onuțu, Iuliana Veronica Ghețiu, Marian Băjan, Gabriel Vasilievici, Dorin Bomboș, Abeer Baioun, Cașen Panaitescu, Ionuț Banu and Romuald Győrgy
ChemEngineering 2025, 9(4), 86; https://doi.org/10.3390/chemengineering9040086 - 8 Aug 2025
Viewed by 134
Abstract
In this study, a novel magnetic nanocatalyst based on tin ferrite (SnFe2O4) was synthesized via a chemical co-precipitation method and thoroughly characterized using XRD, SEM, TGA-DTG, BET, FTIR, and FTIR-pyridine techniques. The catalyst exhibited high crystallinity, a mesoporous structure [...] Read more.
In this study, a novel magnetic nanocatalyst based on tin ferrite (SnFe2O4) was synthesized via a chemical co-precipitation method and thoroughly characterized using XRD, SEM, TGA-DTG, BET, FTIR, and FTIR-pyridine techniques. The catalyst exhibited high crystallinity, a mesoporous structure with a specific surface area of 79.7 m2/g, and well-defined Lewis and Brønsted acid sites. Its catalytic performance was assessed in the esterification of glycerol with acetic acid to produce monoacetin (MAG), diacetin (DAG), and triacetin (TAG). A Box–Behnken experimental design was employed to evaluate the influence of temperature, catalyst loading, and the acetic-acid-to-glycerol molar ratio on product distribution and glycerol conversion. Statistical analysis and regression modeling revealed excellent predictive accuracy (R2 > 0.99), confirming the robustness of the model. Optimal reaction conditions (110 °C, 2 wt.% catalyst, and AA/GLY ratio of 3.6) yielded a maximum glycerol conversion of 93.2% and a combined DAG and TAG yield of ~59.1%. These results demonstrate the high efficiency and selectivity of the synthesized SnFe2O4 catalyst, making it a promising candidate for sustainable glycerol valorization. Full article
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17 pages, 2076 KiB  
Article
Simple and Robust UPLC-MS Method for Serum Arachidonic Acid with Potential Application in Clinical Settings
by Daniela Vankova, Miglena Nikolova, Milka Nashar and Bistra Galunska
Appl. Sci. 2025, 15(16), 8789; https://doi.org/10.3390/app15168789 - 8 Aug 2025
Viewed by 182
Abstract
Arachidonic acid (AA) is a polyunsaturated fatty acid, an essential component of the brain membrane phospholipids. It is released into the bloodstream in response to various pathological conditions. Its potential as a biomarker for oxidative membrane damage determines the importance of its reliable [...] Read more.
Arachidonic acid (AA) is a polyunsaturated fatty acid, an essential component of the brain membrane phospholipids. It is released into the bloodstream in response to various pathological conditions. Its potential as a biomarker for oxidative membrane damage determines the importance of its reliable quantification. Therefore, the aim of the current study was to develop a simple and robust LC-MS method that is easy to implement for routine testing of free arachidonic acid (AA) in human serum. The method included a simple two-step sample preparation procedure based on liquid–liquid extraction and protein precipitation, followed by AA analysis by UPLC coupled with PDA and QDa detectors. The ICH M10 guideline was followed for validation studies. The method demonstrated high selectivity and linearity with R2 = 0.9952 for solvent-based and R2 = 0.9979 for matrix-matched calibration. The LODs and LOQs were 0.046 µg/mL and 0.133 µg/mL, respectively. The accuracy and precision were between 6 and 14% RSD. No carry-over and matrix interferences were observed. The method was successfully applied to real serum samples, where AA concentrations ranged from 0.82 to 2.69 µg/mL, consistent with data of other studies. This method provides a reliable, reproducible, and rapid alternative for AA quantification in research and routine practice. Full article
(This article belongs to the Special Issue Recent Advancements in Biomarkers for Noncommunicable Diseases)
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17 pages, 4238 KiB  
Article
Carbonatogenic Bacteria from Corallium rubrum Colonies
by Vincenzo Pasquale, Roberto Sandulli, Elena Chianese, Antonio Lettino, Maria Esther Sanz-Montero, Mazhar Ali Jarwar and Stefano Dumontet
Minerals 2025, 15(8), 839; https://doi.org/10.3390/min15080839 - 7 Aug 2025
Viewed by 197
Abstract
The precipitation of minerals, in particular carbonates, is a widespread phenomenon in all ecosystems, where it assumes a high relevance both from a geological and biogeochemical standpoint. Most carbonate rocks are of biological origin and made in an aquatic environment. In particular, bioprecipitation [...] Read more.
The precipitation of minerals, in particular carbonates, is a widespread phenomenon in all ecosystems, where it assumes a high relevance both from a geological and biogeochemical standpoint. Most carbonate rocks are of biological origin and made in an aquatic environment. In particular, bioprecipitation of carbonates is believed to have started in the Mesoproterozoic Era, thanks to a process often driven by photosynthetic microorganisms. Nevertheless, an important contribution to carbonate precipitation is also due to the metabolic activity of heterotrophic bacteria, which is not restricted to specific taxonomic groups or to specific environments, making this process a ubiquitous phenomenon. In this framework, the relationship between carbonatogenic microorganisms and other living organisms assumes a particular interest. This study aims to isolate and identify the culturable heterotrophic bacterial component associated with the coenosarc of Corallium rubrum in order to evaluate the occurrence of strains able to precipitate carbonates. In particular, the study was focused on the identification and characterisation of bacterial strains isolated from a coral coenosarc showing a high carbonatogenic capacity under laboratory conditions. Samples of C. rubrum were taken in the coastal waters of three Italian regions. The concentration of the aerobic heterotrophic microflora colonising C. rubrum coenosarc samples spanned from 3 to 6∙106 CFU/cm2. This variation in microbial populations colonising the C. rubrum coenosarc, spanning over 6 orders of magnitude, is not mirrored by a corresponding variability in the colony morphotypes recorded, with the mean being 5.1 (±2.1 sd). Among these bacteria, the carbonatogenic predominant species was Staphylococcus equorum (93% of the isolates), whereas Staphylococcus xylosus and Shewanella sp. accounted only for 3% of isolates each. All these strains showed a remarkable capacity of precipitating calcium carbonate, in the form of calcite crystals organised radially as well crystalised spherulites (S. equorum) or coalescing spherulites (Shewanella sp.). S. xylosus only produced amorphous precipitates of calcium carbonate. All bacterial strains identified were positive both for the production of urease and carbon anhydrase in vitro at 30 °C. It seems that they potentially possess the major biochemical abilities conducive to Ca2+ precipitation, as they showed in vitro. In addition, all our carbonatogenic isolates were able to hydrolyse the phytic acid calcium salt and then were potentially able to induce precipitation of calcium phosphates also through such a mechanism. Full article
(This article belongs to the Special Issue Carbonate Petrology and Geochemistry, 2nd Edition)
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14 pages, 2584 KiB  
Article
Enhanced Catalytic Ozonation of Formaldehyde over MOFs- Derived MnOx Catalysts with Diverse Morphologies: The Role of Oxygen Vacancies
by Yulin Sun, Yiwei Zhang, Yong He, Wubin Weng, Yanqun Zhu and Zhihua Wang
Catalysts 2025, 15(8), 752; https://doi.org/10.3390/catal15080752 - 6 Aug 2025
Viewed by 397
Abstract
Metal–organic frameworks (MOFs) have become a hot topic in various research fields nowadays. And MOF-derived metal oxides prepared by the sacrificial template method have been widely applied as catalysts for pollutant removal. Accordingly, we prepared a series of MOF-derived MnOx catalysts with [...] Read more.
Metal–organic frameworks (MOFs) have become a hot topic in various research fields nowadays. And MOF-derived metal oxides prepared by the sacrificial template method have been widely applied as catalysts for pollutant removal. Accordingly, we prepared a series of MOF-derived MnOx catalysts with diverse morphologies (rod-like, flower-like, slab-like) via the pyrolysis of MOF precursors, and the as-prepared MnOx catalysts demonstrated superior performance compared to the one prepared using the co-precipitation method. MnOx-II, with a flower-like structure, exhibited excellent activity for formaldehyde (HCHO) catalytic ozonation at room temperature, reaching complete HCHO conversion at O3/HCHO of 1.5 and more than 90% CO2 selectivity at an O3/HCHO ratio of 2.5. On the basis of various characterization methods, it was clarified that the enhanced catalytic performance of MnOx-II benefited from its larger BET surface area, abundant oxygen vacancies, better redox ability at lower temperature, and more Lewis acid sites. The H2O resistance and stability tests were also conducted. Furthermore, DFT calculations substantiated the enhanced adsorption of HCHO and O3 on oxygen vacancies, while in–situ DRIFTS measurements elucidated the degradation pathway of HCHO during catalytic ozonation through detected intermediates. Full article
(This article belongs to the Special Issue Catalysis Accelerating Energy and Environmental Sustainability)
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13 pages, 2036 KiB  
Article
Aluminum Extractions by the Alkali Method Directly from Alkali-Acid (NaOH-HCl) Chemical Deashing of Coals
by Lijun Zhao
Materials 2025, 18(15), 3661; https://doi.org/10.3390/ma18153661 - 4 Aug 2025
Viewed by 289
Abstract
An advanced alkali-acid (NaOH-HCl) chemical method was used to deash aluminum-rich coals (ARCs) with a high ash content of 27.47 wt% to achieve a low ash content of 0.46 wt%. In the deashing process, aluminum in the coal ashes was dissolved in both [...] Read more.
An advanced alkali-acid (NaOH-HCl) chemical method was used to deash aluminum-rich coals (ARCs) with a high ash content of 27.47 wt% to achieve a low ash content of 0.46 wt%. In the deashing process, aluminum in the coal ashes was dissolved in both alkali solutions and acid solutions. The deashing alkali solutions with dissolved coal ashes were regenerated by adding CaO, and the resulting precipitates were added with sodium bicarbonate for aluminum extraction. High temperatures increased aluminum extraction, and excessive sodium bicarbonate addition decreased aluminum extraction. The deashing acid solutions were concentrated by evaporation, and silica gels formed during the process. The obtained mixtures were calcinated at 350 °C for the decomposition of aluminum chlorides, and soaked with water at 60 °C to remove the soluble chlorides. For the insoluble oxides after soaking, diluted alkali solutions were used to extract the aluminum at 90 °C, and aluminum extraction failed due to the formation of albite in the presence of sodium, aluminum and silicon elements as proved by XRD and SEM/EDS. When silica gels were separated by pressure filtering, aluminum extraction greatly increased. Aluminum extractions were accordingly made in the form of sodium aluminate from the deashing solutions of coals, which could be advantageous for sandy alumina production. Full article
(This article belongs to the Section Materials Chemistry)
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16 pages, 7102 KiB  
Article
Effect of Calcium Sulfate and Silica Gel on Vanadium Leaching Characteristics from Vanadium Titanomagnetite via Calcification Roasting–Sulfuric Acid Leaching: Formation Mechanism and Process Enhancement
by Jianli Chen, Yu Zheng, Benliu He, Shuzhong Chen, Shuai Wang, Feng Chen, Shiyuan Cui, Jing Liu, Lingzhi Yang, Yufeng Guo and Guanzhou Qiu
Metals 2025, 15(8), 870; https://doi.org/10.3390/met15080870 - 3 Aug 2025
Viewed by 217
Abstract
Compared with vanadium extraction by sodium roasting followed by water leaching, the calcification roasting–sulfuric acid leaching method is considered a promising approach for the comprehensive utilization of vanadium titanomagnetite, as it avoids the introduction of alkali metals. However, during vanadium extraction by sulfuric [...] Read more.
Compared with vanadium extraction by sodium roasting followed by water leaching, the calcification roasting–sulfuric acid leaching method is considered a promising approach for the comprehensive utilization of vanadium titanomagnetite, as it avoids the introduction of alkali metals. However, during vanadium extraction by sulfuric acid heap leaching, the diffusion of leaching reagents and leaching products was hindered by the deposition of leaching solid products. To address this issue, this study systematically investigated the leaching kinetics and the mechanisms underlying the deposition of leaching solid products. The results indicated that vanadium leaching was governed by a combination of liquid film diffusion and internal diffusion through solid-phase products during days 0–2, and by internal diffusion alone from day 2 to day 9. The primary solid products formed during leaching were calcium sulfate and silica gel. Calcium sulfate precipitated and grew within the pore via two-dimensional nucleation, while silicates formed silica gel through dehydration. By optimizing the sulfuric acid leaching conditions—specifically, maintaining an H+ concentration of 2 mol/L, a leaching temperature of 40 °C, and a liquid-to-solid ratio of 5:1—the formation of calcium sulfate and silica gel was effectively suppressed. Under these conditions, the vanadium leaching efficiency reached 75.82%. Full article
(This article belongs to the Section Extractive Metallurgy)
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13 pages, 2629 KiB  
Article
Seed Germination Requirements of the Threatened Local Greek Endemic Campanula pangea Hartvig Facilitating Species-Specific Conservation Efforts
by Margarita Paradisiotis, Elias Pipinis, Stefanos Kostas, Georgios Tsoktouridis, Stefanos Hatzilazarou, Anna Mastrogianni, Ioannis Tsiripidis and Nikos Krigas
Conservation 2025, 5(3), 39; https://doi.org/10.3390/conservation5030039 - 1 Aug 2025
Viewed by 750
Abstract
Ex situ conservation is a vital strategy of preserving plant species at risk, offering practical methods to obtain information regarding species-specific germination characteristics. Campanula pangea, a local endemic species of NE Greece, has been previously classified as vulnerable, partly due to the [...] Read more.
Ex situ conservation is a vital strategy of preserving plant species at risk, offering practical methods to obtain information regarding species-specific germination characteristics. Campanula pangea, a local endemic species of NE Greece, has been previously classified as vulnerable, partly due to the lack of knowledge about its biology. This study focused on the germination behaviour of C. pangea stored seeds by assessing their germination success under the effects of incubation temperature and gibberellic acid (GA3). To contextualize the experimental conditions, a bioclimatic profile of the species was developed using open-access temperature and precipitation data that characterize its natural habitat. The results showed that the optimal germination temperature range for C. pangea is 15–20 °C. Pre-treatment of seeds with GA3 solution (1000 mg L−1) widened the germination range of the seeds only at the low temperature of 10 °C. The experimentation results showed that the seeds of C. pangea exhibit dormancy. These findings contribute to the development of a species-specific germination protocol for ex situ propagation and conservation, enhance understanding of the species’ germination requirements, and thus support future conservation efforts and assessments of extinction risk, or other ornamental applications and/or targeted medicinal research. Full article
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13 pages, 1750 KiB  
Article
Mineral-Based Synthesis of CuFe2O4 Nanoparticles via Co-Precipitation and Microwave Techniques Using Leached Copper Solutions from Mined Minerals
by Carolina Venegas Abarzúa, Mauricio J. Morel, Gabriela Sandoval-Hevia, Thangavel Kavinkumar, Natarajan Chidhambaram, Sathish Kumar Kamaraj, Nagarajan Dineshbabu and Arun Thirumurugan
Minerals 2025, 15(8), 819; https://doi.org/10.3390/min15080819 - 1 Aug 2025
Viewed by 265
Abstract
Environmental sustainability and responsible resource utilization are critical global challenges. In this work, we present a sustainable and circular-economy-based approach for synthesizing CuFe2O4 nanoparticles by directly utilizing copper oxide minerals sourced from Chilean mining operations. Copper sulfate (CuSO4) [...] Read more.
Environmental sustainability and responsible resource utilization are critical global challenges. In this work, we present a sustainable and circular-economy-based approach for synthesizing CuFe2O4 nanoparticles by directly utilizing copper oxide minerals sourced from Chilean mining operations. Copper sulfate (CuSO4) was extracted from these minerals through acid leaching and used as a precursor for nanoparticle synthesis via both chemical co-precipitation and microwave-assisted methods. The influence of different precipitating agents—NaOH, Na2CO3, and NaF—was systematically evaluated. XRD and FESEM analyses revealed that NaOH produced the most phase-pure and well-dispersed nanoparticles, while NaF resulted in secondary phase formation. The microwave-assisted method further improved particle uniformity and reduced agglomeration due to rapid and homogeneous heating. Electrochemical characterization was conducted to assess the suitability of the synthesized CuFe2O4 for supercapacitor applications. Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurements confirmed pseudocapacitive behavior, with a specific capacitance of up to 1000 F/g at 2 A/g. These findings highlight the potential of CuFe2O4 as a low-cost, high-performance electrode material for energy storage. This study underscores the feasibility of converting primary mined minerals into functional nanomaterials while promoting sustainable mineral valorization. The approach can be extended to other critical metals and mineral residues, including tailings, supporting the broader goals of a circular economy and environmental remediation. Full article
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17 pages, 6856 KiB  
Article
Selection of Optimal Parameters for Chemical Well Treatment During In Situ Leaching of Uranium Ores
by Kuanysh Togizov, Zhiger Kenzhetaev, Akerke Muzapparova, Shyngyskhan Bainiyazov, Diar Raushanbek and Yuliya Yaremkiv
Minerals 2025, 15(8), 811; https://doi.org/10.3390/min15080811 - 31 Jul 2025
Viewed by 229
Abstract
The aim of this study was to improve the efficiency of in situ uranium leaching by developing a specialized methodology for selecting rational parameters for the chemical treatment of production wells. This approach was designed to enhance the filtration properties of ores and [...] Read more.
The aim of this study was to improve the efficiency of in situ uranium leaching by developing a specialized methodology for selecting rational parameters for the chemical treatment of production wells. This approach was designed to enhance the filtration properties of ores and extend the uninterrupted operation period of wells, considering the clay content of the productive horizon, the geological characteristics of the ore-bearing layer, and the composition of precipitation-forming materials. The mineralogical characteristics of ore and precipitate samples formed during the in situ leaching of uranium under various mining and geological conditions at a uranium deposit in the Syrdarya depression were identified using an X-ray diffraction analysis. It was established that ores of the Santonian stage are relatively homogeneous and consist mainly of quartz. During well operation, the precipitates formed are predominantly gypsum, which has little impact on the filtration properties of the ore. Ores of the Maastrichtian stage are less homogeneous and mainly composed of quartz and smectite, with minor amounts of potassium feldspar and kaolinite. The leaching of these ores results in the formation of gypsum with quartz impurities, which gradually reduces the filtration properties of the ore. Ores of the Campanian stage are heterogeneous, consisting mainly of quartz with varying proportions of clay minerals and gypsum. The leaching of these ores generates a variety of precipitates that significantly reduce the filtration properties of the productive horizon. Effective compositions and concentrations of decolmatant (clog removal) solutions were selected under laboratory conditions using a specially developed methodology and a TESCAN MIRA scanning electron microscope. Based on a scanning electron microscope analysis of the samples, the effectiveness of a decolmatizing solution based on hydrochloric and hydrofluoric acids (taking into account the concentration of the acids in the solution) was established for the destruction of precipitate formation during the in situ leaching of uranium. Geological blocks were ranked by their clay content to select rational parameters of decolmatant solutions for the efficient enhancement of ore filtration properties and the prevention of precipitation formation. Pilot-scale testing of the selected decolmatant parameters under various mining and geological conditions allowed the optimal chemical treatment parameters to be determined based on the clay content and the composition of precipitates in the productive horizon. An analysis of pilot well trials using the new approach showed an increase in the uninterrupted operational period of wells by 30%–40% under average mineral acid concentrations and by 25%–45% under maximum concentrations with surfactant additives in complex geological settings. As a result, an effective methodology for ranking geological blocks based on their ore clay content and precipitate composition was developed to determine the rational parameters of decolmatant solutions, enabling a maximized filtration performance and an extended well service life. This makes it possible to reduce the operating costs of extraction, control the geotechnological parameters of uranium well mining, and improve the efficiency of the in situ leaching of uranium under complex mining and geological conditions. Additionally, the approach increases the environmental and operational safety during uranium ore leaching intensification. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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