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Biochar derived from the invasive aquatic plant Myriophyllum spicatum: Characterization via SEM–EDX and application in lead removal
No full textThe accumulation of lead (Pb) in aquatic environments remains a significant environmental challenge due to its toxicity and persistence. Meanwhile, invasive aquatic plants, such as Myriophyllum spicatum, cause ecological and economic issues due to their rapid growth and extensive biomass production. Converting this problematic biomass into biochar presents an opportunity to address both issues simultaneously. This study investigates biochar derived from M. spicatum via pyrolysis at 600°C, characterized using SEM–EDX, for its effectiveness in removing lead from aqueous solutions. Pyrolysis decreased carbon content through the conversion of organic carbon into volatile products, while the non-volatile calcium content increased more than fourfold. Pb(II) adsorption capacities improved significantly, from 73.9 mg/g in raw biomass to 92.4 mg/g in biochar, indicating an enhancement of over 20% in lead removal efficiency. These findings demonstrate the potential of biochar from invasive aquatic plants as a sustainable and effective solution for remediating lead-contaminated water, thus supporting the principles of the circular economy and contributing to ecosystem restoration
Green extraction of critical metals: Chemical leaching and electrochemical recovery from coal
No full textThis study investigates the selective recovery of critical metals from coal through chemical
leaching and electrochemical processes, with a focus on copper (Cu) recovery. Chemical
leaching was performed using 15 vol.% HNO₃ at 60 °C for 30 minutes per cycle. After each
leaching step, a new coal sample was introduced, while the used acid was replenished
with concentrated HNO₃ to maintain a consistent 15 vol.% concentration. This process
was repeated for six cycles, leading to the progressive accumulation of leached metal ions
in the solution.
The composition of the leachate, analyzed via ICP-OES, revealed increasing
concentrations of metals, with Fe and Zn being predominant. Electrochemical studies,
including cyclic voltammetry (CV) and linear sweep voltammetry (LSV), were conducted to
evaluate the feasibility of Cu recovery and the influence of co-leached metals, particularly
Pb and Fe. LSV results demonstrated that Pb did not significantly hinder Cu recovery, as
indicated by distinct Cu redox peaks. Selective Cu deposition was achieved by controlling
the applied potential, with reduction occurring at -0.70 V. Furthermore, Cu was
successfully deposited by holding the potential at -0.10 V and subsequently oxidized at
approximately 0.15 V during the anodic sweep, confirming its electrochemical
recoverability.
These findings highlight the potential of chemical leaching combined with
electrochemical recovery as a sustainable strategy for extracting critical metals from coal.
This approach supports circular economy principles by minimizing waste, reducing the
need for virgin raw materials and valorizing coal as a secondary resource for metal
recovery
Geološko tehnološke karakteristike ležišta zeolitskog tufa Igroš
No full textLežište zeolitskog tufa „Igroš“ pripada Kruševačkom neogenom basenu i nalazi se u ataru sela Igroš. Prostire se na oko 8km istočno od mesta Brus i 3 km severoistočno od reke Rasine. Na ispitivanom delu terena u lokalitetu Igroš izdvojena su dva rudna polja: rudno polje Šovići-Đorđevići i rudno polje Igroš-Vidojevići. Uzorci zeolitskog tufa koji su korišćeni za ispitivanja prikazana u ovom radu su uzeti sa eksploatacionog polja „Igroš-Vidojevići“ – atar sela Igroš. U radu su prikazani rezultati ispitivanja navedenih uzoraka zeolitskog tufa u cilju sagledavanja mineragenetskih karakteristika ležišta, utvrđivanja kvaliteta zeolita, njegove primene i načina valorizacije. U karakterizaciji uzoraka primenjene su sledeće metode: elementna hemijska analiza, određivanje kapaciteta katjonske izmene (KKI) kao i rendgenska difrakcija praha (RDP)
Advancements in comminution equipment for mining: innovations in crushing and grinding technologies
No full textComminution, which includes crushing and grinding, is one of the most energy-intensive processes in the mining industry, accounting for up to 50% of total energy consumption in mineral processing plants. Recent technological advancements have introduced more efficient, cost-effective, and environmentally friendly comminution equipment. This paper reviews the latest innovations in crushing and grinding technologies, including high-pressure grinding rolls (HPGR), vertical roller mills (VRM), and advanced cone crushers with real-time optimization systems. The study evaluates the energy efficiency, operational performance, and economic feasibility of these devices compared to traditional equipment such as ball mills and jaw crushers. The findings suggest that adopting modern comminution technologies can significantly reduce energy consumption, improve particle size distribution, and lower operational costs. These advancements contribute to more sustainable mining operations by minimizing environmental impact and optimizing resource utilization
Solvent-dependent kinetics of polyphosphate glass hydrolysis
No full textUnderstanding the dissolution kinetics of phosphate glasses is essential for designing materials with tailored durability, optimizing their performance across various applications, and minimizing their environmental impact. The hydrolysis of phosphate glass refers to its degradation in the presence of water, where phosphate bonds break, leading to the gradual dissolution of the glass network. This process is influenced by factors such as composition, pH, temperature, and the presence of ions within the glass matrix. This study investigates the hydrolysis kinetics of polyphosphate glass in deionized water and a 2% citric acid solution, focusing on how solvent properties affect the dissolution process. Experimental results indicate that ion release rates range from 8.74 x 10⁻⁴ to 5.44 x 10⁻² g/m²h in deionized water, while in a 2% citric acid solution, they vary from 1.76 x 10⁻³ to 6.92 x 10⁻² g/m²·h. The activation energies for ion release during hydrolysis are 41.5 to 65.2 kJ/mol in deionized water and 49.1 to 85.3 kJ/mol in the citric acid solution. Additionally, this paper presents the results of FTIR analyses of polyphosphate glass samples, before and after dissolution in both solvents, providing further insight into the material’s degradation behavior
Surfactant-modified kaolin – Adsorbent for ochratoxin A and ketoprofen
No full textThis study investigates the potential of surfactant-modified kaolin as an adsorbent for two different purposes: the decontamination of animal feed and the removal of pharmaceuticals from water. The model substances selected for this research were ochratoxin A (OCHRA), a mycotoxin commonly found in animal feed, and ketoprofen (KET), a nonsteroidal anti-inflammatory drug (NSAID) often detected in water sources. The natural kaolin was modified with quaternary ammonium salt (hexadecyltrimethylammonium – HDTMA bromide) in an amount equal to 50% of kaolin's cation exchange capacity (CEC). The successful modification was confirmed by two characterization methods - Fourier Transformed Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Adsorption experiments were performed at different initial concentrations of investigated pollutants at pH 7. The results of this study reveal that the modification of kaolin with organic cations significantly enhances its ability to adsorb both OCHRA and KET, with adsorption efficiency increasing as the concentration of investigated analytes rise. This research demonstrates that surfactant-modified kaolin exhibits high adsorption capacity for both contaminants, with significant improvement in removal efficiency compared to unmodified kaolin, highlighting its potential as an effective adsorbent for environmental and health risks associated with these substances
The preferred orientation of electrodeposited dendrites of lead, tin and zinc
No full textMorphology and crystal orientation of electrolytically produced dendrites of lead, tin, and zinc have been investigated with the aim of establishing any correlation between them. These three metals belong to the same group of metals from an electrochemical point of view (the group of normal metals), but to various types of crystal lattice (Pb - the face-centered cubic type, Sn - the body-centered tetragonal type, and Zn - the hexagonal closed pack type). Pb, Sn and Zn dendrites were produced potentiostatically using the corresponding hydroxide electrolytes and characterized by scanning electron microscopy (morphology) and X-ray diffraction (crystal orientation) techniques. The preferred orientation of the dendritic particles was determined by applying a method based on a comparison of the peak intensity ratios. The fern-like dendrites of various degrees of branchy were obtained by the processes of electrolysis, and regardless of the type of crystal lattice, they exhibited the strong preferred orientation in crystal planes with the lowest surface energy. Based on the performed analysis, a strong correlation between the morphology and the crystal structure of dendrites belonging to the group of normal metals has been established. It is concluded that electrochemical parameters characterized by the high values of the exchange current density (the fast electrochemical processes) prevailed over crystallographic characteristics of metals manifested by the belonging to a determined type of crystal lattice
Luminomagnetic Fe₃O₄ Nanostructures for Biomedical Application: Synthesis, Characterization, and Antibacterial Properties
No full textLuminomagnetic Fe₃O₄ nanostructures, which combine magnetic and optical properties, represent a promising material for a wide range of biomedical applications, including targeted drug delivery, magnetic resonance imaging, and hyperthermia [1]. In this study, we report the synthesis and systematic investigation of luminomagnetic Fe₃O₄ nanostructures with a rod-like morphology. The Fe₃O₄ nanostructures were synthesized using a reduction-precipitation method to achieve structures with controlled sizes and morphologies. Characterization of these nanostructures included field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, as well as superconducting quantum interference device (SQUID) and fluorescence spectroscopy (PL) to analyze their magnetic and optical properties. The obtained nanostructures exhibit good magnetization along with light emission, making them suitable for in vivo biosensing and magnetic therapies. Additionally, antibacterial properties were tested on S. aureus cells, demonstrating that these nanostructures can also serve as antibacterial agents. This work highlights the potential of Fe₃O₄ nanostructures as multifunctional materials in bioengineering and biomedical devices, with applications in drug targeting, magnetic resonance imaging, hyperthermia treatments, and as innovative antibacterial agents
Examples of removing benign lesions using the chemical method according to Dr. G. Dunkic
No full textIn practice, patients with a large number of benign lesions are often encountered, which are impractical to remove using classical methods such as surgery, laser or radio wave methods. Therefore, a method of removing benign lesions with a chemical preparation according to Dr. Dunkic has been developed, which does not require anesthesia, can be applied simultaneously to a large number of lesions, and is very comfortable for patients. The paper presents examples of the application of the chemical method of removing benign lesions on two patients. Monitoring of patients, even after many years from the moment of removal of the lesions, no changes were observed in the treated areas
Geochemical Evaluation of Dolostone Deposits in Montenegro: Implications for Potential Industrial Applications
No full textDolomite is a valuable mineral commodity with numerous industrial applications. Dolostones are mineral resources with significant growth potential. The study area encompasses south and central Montenegro. Mineralogical, petrographic, geochemical, and technological properties were investigated. Upper Cretaceous dolostones are compact and contain organic matter, whereas Triassic dolostones are weathered dolomites without organic matter. Both of formations displayed varying dolostone quality, prompting the geological and technological classification of Montenegrin dolostones. Upper Cretaceous dolostones are utilized in the building industry as aggregate, dimension stone, and filler, whereas Triassic dolomites are not suitable as dimension stone and have limited potential as aggregate. Both dolostones can be utilized in the steel industry and agriculture, but not as high-quality fillers when whiteness is a limitation, or for lime production where chemical composition and grain size are regulated. This is the first comprehensive study of geochemical evaluations of dolostone deposits in the Balkans and their potential industrial use