Search Results (2,938)

A Ce-doped photocatalytic composite with easy solid–liquid separation capability was prepared and a heterojunction was constructed between BiVO₄ and Fe₃O₄ via a co-precipitation method. A variety of characterization techniques were employed, such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible spectroscopy (UV-vis), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS), as well as other related methods. Its photocatalytic performance for the degradation of Rhodamine B (RhB) was also studied. The results indicate that the photocatalytic efficiency of BiVO₄/Fe₃O₄ is 1.4 times that of the pure BiVO₄ matrix. In particular, the photocatalytic efficiency of Ce_1.5%-BiVO₄/Fe₃O₄ was 2.2 times higher than that of the pure BiVO₄ matrix, and a 100% degradation rate of RhB was achieved within 30 min. The introduction of Fe₃O₄ not only forms a heterojunction with BiVO₄, increasing the active sites and surface oxygen vacancies of the material and effectively suppressing the recombination of photogenerated electron (e^-)-hole (h⁺) pairs, but it also enables the rapid separation of the material from the wastewater solution by the magnetic properties of Fe₃O₄. Additionally, the partial substitution of Ce for Bi in the BiVO₄ lattice reduces the bandgap energy, which enhances the utilization efficiency of visible light and improves the photocatalytic performance of the composite material. The mechanism of RhB degradation by Ce_1.5%-BiVO₄/Fe₃O₄ composite materials is also analyzed in this study. Quenching experiments and EPR tests revealed that h⁺ and ${·\mathrm{O}}_2^{-}$ were the primary reactive species in the degradation process. Full article

Pelletizing is an effective way of converting abundant phosphate ore fines into usable feedstocks for yellow-phosphorus production. In this work, the oxidation-roasting behavior of siliceous–calcareous phosphate ore pellets and siliceous phosphate ore pellets was evaluated in a laboratory tube furnace. The consolidation mechanisms were revealed using optical microscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The results indicate that siliceous phosphate ore pellets exhibit superior oxidation-roasting performance relative to siliceous–calcareous phosphate ore pellets. After roasting, oxidized siliceous–calcareous phosphate ore pellets show a loose and porous framework with large pores, thin walls, and occasional surface cracking. The consolidation of siliceous–calcareous phosphate ore pellets is mainly governed by the recrystallization bonding of silicon–magnesium-bearing fluorapatite. In contrast, oxidized siliceous phosphate ore pellets display a denser microstructure and stronger intergranular bonding. The dominant bonding forms are the recrystallization bonding of silicon-bearing fluorapatite and solid-state bonding between silicon-bearing fluorapatite particles and quartz particles. Furthermore, carbonate gangue minerals are detrimental to strength development because CO₂ release during roasting promotes the development of interconnected porosity and defects, thereby reducing the compressive strength of oxidized phosphate ore pellets. Full article

Improving the dissolution and solubility of poorly water-soluble drugs remains a major challenge in drug development. Solid dispersion (SD) techniques offer an effective strategy by which to enhance the bioavailability of BCS Class II drugs such as ivermectin (IVM). This study aimed to develop and validate stability-indicating analytical methods for the quantification of IVM and to evaluate the performance of the formulated SDs. A novel RP-HPLC and a UV spectrophotometric method were developed and validated in accordance with ICH guidelines. IVM SDs were prepared via physical mixing (PM), solvent evaporation (SE), and melt fusion (MF) using Poloxamer 188, Kollicoat^® IR, and PEG 6000 at respective ratios of 1:1, 1:3, and 1:5. Dissolution studies showed a marked enhancement in drug release from SDs prepared by SE and MF methods compared with pure IVM. Among all formulations, the Poloxamer 188-based binary SD prepared by the SE method at a 1:5 ratio exhibited the highest dissolution (98.55% at 60 min), with release kinetics following anomalous (non-Fickian) transport (n = 0.681) according to the Korsmeyer–Peppas model. Solid-state characterization evidenced by FTIR, DSC, TGA, and SEM confirmed the transformation of IVM from its crystalline form to an amorphous state. Future studies will focus on the in vivo evaluation of the optimized IVM SD formulations. Full article

Metal-functionalized boron nitride nanostructures represent promising platforms for lightweight solid-state hydrogen storage. In this work, we perform a comprehensive density functional theory (DFT) investigation of pristine and metal-decorated B₄N₄ quantum dots (M = Li, Ti) to evaluate their structural stability, adsorption energetics, and near-ambient storage performance. Pristine B₄N₄ is highly stable but interacts weakly with H₂ (E_ads ≈ −0.12 eV), leading to negligible uptake under operating conditions. Li decoration moderately enhances adsorption through charge-induced polarization (E_ads ≈ −0.15 eV) but offers limited stabilization beyond the first few molecules. In contrast, Ti decoration fundamentally reshapes the interaction landscape, strengthening electrostatic, polarization, and dispersion contributions and enabling significantly stronger yet reversible H₂ binding (E_ads ≈ −0.36 eV). Sequential adsorption calculations predict maximum theoretical capacities of 14, 18, and 20 H₂ molecules for pristine, Li-, and Ti-decorated systems, respectively. Grand canonical thermodynamics show that Ti–B₄N₄ retains nearly its full loading at 30 bar and 298 K, while pristine and Li-decorated clusters store only negligible amounts. Under desorption conditions (3 bar, 373 K), Ti–B₄N₄ releases most of its stored hydrogen, yielding an exceptional reversible capacity of 15.1 wt%. Energy decomposition analysis attributes this performance to cooperative electrostatic, polarization, and dispersion enhancements. Ti–B₄N₄ emerges as a highly promising theoretical candidate, warranting future experimental validation. Full article

Blade-Free Planetary Mixer (BFPM) can rapidly and efficiently mix highly viscous materials because of the strong centrifugal forces generated by the planetary motion of the mixing vessel. The safety of energetic propellant slurry during BFPM processing is critical. In this work, the mixing performance and process safety of composite solid propellant slurry in a BFPM were investigated through morphology observation, mixing index analysis, temperature measurement, rheological testing, mechanical sensitivity evaluation, and thermal analysis. The results showed that the BFPM achieved safe, efficient, and uniform mixing of the slurry. Under the baseline condition of 1000 rpm, the mixing index reached 95.73% after 24 min, and the slurry temperature increased to only 31.1 °C. The influence of BFPM processing on slurry safety was mainly reflected in the spatial redistribution of energetic solid components and the solid–liquid mixing state. And mechanical sensitivity tended to increase in regions of higher apparent viscosity. Increasing the rotational speed and adopting alternating rotation promoted particle dispersion and reduced local apparent viscosity, but an excessively high rotational speed reduced thermal stability. Overall, 1200 rpm combined with alternating rotation was identified as the most suitable operating condition. This work provides a practical basis for the safe and efficient BFPM processing of energetic propellant slurries. Full article

This study investigates the influence of design factors and key process parameters—including explosive welding (EXW), rolling, and laser processing—on the formation, microstructure, and tribological properties of Ti–Cu–Ni intermetallic coatings. A combined manufacturing approach was employed, starting with the EXW of an MN19 cupronickel alloy to a VT1-0 titanium substrate, followed by multi-pass rolling to achieve a cladding thickness of approximately 0.3 mm. Subsequently, laser surface remelting was performed to facilitate controlled mass transfer and homogenization within the reaction zone. Numerical simulation using COMSOL Multiphysics v. 5.4 was utilized to optimize the thermal cycles and determine the ideal energy density (42 J/mm²) for phase formation. The results demonstrate that the primary structural components of the coatings produced under optimal conditions are solid solutions based on the ternary-modified titanium cuprides Ti₂Cu(Ni) and TiCu(Ni). The transition from a layered bimetal to a finely dispersed intermetallic structure significantly enhances the surface characteristics. This specific phase composition provides a sustained microhardness of ~5 GPa across the coating cross-section. Comparative wear tests against fixed abrasive revealed that the wear resistance of the Ti–Cu–Ni coatings is 2.5 times higher at room temperature and 1.5 times higher at 600 °C than that of the base VT1-0 titanium. Full article

Background/Objectives: Cannabidiol (CBD) has emerged as a potential therapeutic agent for respiratory disorders, including asthma and chronic obstructive pulmonary disease. However, its clinical translation via pulmonary delivery is limited by poor aqueous solubility, chemical instability, and low local bioavailability. This study aimed to develop and optimize a sodium stearate (NaSt)-based spray-dried dry powder inhaler (DPI) formulation to enhance the aerosol performance, dissolution, and storage stability of CBD. Methods: CBD microparticles were prepared by spray drying using NaSt as the primary excipient. The feed preparation method, spray-drying parameters, and CBD:NaSt ratios were systematically optimized. The resulting powders were evaluated for aerodynamic properties using cascade impaction, dissolution behavior in simulated lung fluid, solid-state characteristics, and accelerated stability under stress conditions. Results: The optimized formulation, SD-4, a spray-dried CBD:NaSt formulation prepared at a 20:80 weight ratio using Process B, demonstrated excellent aerosolization performance, with a fine particle fraction (FPF) exceeding 50% and a mass median aerodynamic diameter (MMAD) of 5.08 ± 0.1 μm. Dissolution testing revealed more than a three-fold increase in drug release compared with raw CBD, attributed to amorphous dispersion within the NaSt matrix and surfactant-induced micellization. Accelerated stability studies confirmed improved retention of the amorphous state and drug content, while antioxidant incorporation further reduced oxidative degradation. Conclusions: The NaSt-based spray-dried formulation significantly improved aerosol deposition efficiency, dissolution rate, and physicochemical stability of CBD. This formulation strategy may provide a promising platform for pulmonary delivery of poorly water-soluble compounds. Full article

Copper anodic slime is often smelted with lead to improve silver and gold recovery, generating a fine lead-rich fly ash that contains notable amounts of selenium and tellurium. Due to its high lead content and sub-micron particle size, this residue poses significant environmental and occupational health risks. This study evaluates sodium carbonate (Na₂CO₃) leaching as an environmentally benign pre-treatment aimed at partially removing selenium and tellurium while stabilizing lead through carbonate formation. The goal is detoxification rather than maximum metal recovery, enabling safer disposal or subsequent recycling. A central composite design (CCD) in Design-Expert software (Version 12) was used to assess the effects of Na₂CO₃ concentration, temperature, solid-to-liquid ratio, and time on selenium and tellurium dissolution. Selenium recovery reached up to 53.9%, while tellurium recovery peaked at approximately 33.9%. Scanning electron microscopy showed the dust to consist mainly of semi-spherical and elongated particles, with lead carbonate forming preferentially on particle surfaces during leaching. Energy-dispersive spectroscopy confirmed conversion of lead sulfate phases to lead carbonate, which increasingly restricted selenium and tellurium dissolution. Kinetic evaluation suggested selenium leaching follows mixed control involving both surface reaction and diffusion through product layers, whereas tellurium dissolution lacked consistent kinetic behavior. Thermodynamic calculations supported the stabilization of lead as cerussite (PbCO₃), indicating improved environmental safety. The overall dissolution trends were successfully represented using an apparent Shrinking Core Model (SCM) based on measurements collected at 20 °C, 60 °C, and 100 °C. Full article

Municipal solid waste (MSW) landfills are seldom regarded as potential sources of airborne mineral fibres, notwithstanding the possible presence of legacy asbestos-containing materials within mixed waste streams. Prolonged exposure to asbestos fibres is well established as causally associated with severe adverse health outcomes, prompting stringent regulatory measures across the European Union, most recently reinforced by Directive (EU) 2023/2668 amending Directive 2009/148/EC on the protection of workers from the risks related to asbestos exposure. This study presents systematic annual monitoring of airborne mineral fibres (MinFib), including asbestos fibres (AsbFib), conducted between 2019 and 2025 at an MSW landfill in the Czech Republic. Personal air sampling targeted heavy equipment operators as the most exposed occupational group and was conducted in accordance with established occupational hygiene principles. Fibre identification and quantification were carried out using Scanning Electron Microscopy coupled with Energy-Dispersive X-ray analysis (SEM/EDX) according to accredited laboratory internal standard operating procedures (SOPs). Across all monitoring campaigns, asbestos fibre concentrations remained below the analytical detection limits, including during handling of asbestos-containing materials. However, the analytical sensitivity appears to be within the range relevant to the current EU occupational exposure limit (0.01 fibres/cm³), potentially limiting the ability to identify very low-level exposures. These findings indicate that occupational exposure under routine operational conditions was below analytical detection limits, suggesting a low exposure potential. However, non-detectable results should be interpreted as method-limited rather than as indicating that exposure did not occur. Continued monitoring using more sensitive analytical approaches is therefore warranted. Full article

Coal gangue (CG) ranks among China’s most significant industrial solid by-products. In response to China’s carbon neutrality commitments and the growing emphasis on resource recycling, finding effective ways to valorize CG has emerged as a pressing concern. Based on the mineral composition and chemical composition characteristics of CG, this study systematically investigated the enhancement effects of three alkali activators (Na₂SiO₃, NaOH, and Ca(OH)₂) on the cementitious properties of CG. Through different dosage and compressive strength tests, the efficiency ranking of the three activators was determined as follows: Na₂SiO₃ > Ca(OH)₂ > NaOH. A 10% Na₂SiO₃ dosage combined with 28-day curing was identified as the optimal condition for achieving sufficient reaction and structural densification. Under these conditions, the compressive strength of CG cementitious material reached 6.4 MPa, representing an increase of 190.9% compared to the blank group (2.2 MPa), significantly superior to Ca(OH)₂ (69.55%) and NaOH (62.27%). X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analyses revealed that alkali activators function primarily by disrupting the crystalline framework of CG, promoting the cross-linking polymerization of silicon–aluminum monomers to generate dense cementitious products, thereby improving material performance. The Na₂SiO₃ is attributed to its “dual activation effect”, providing OH⁻ to create an alkaline environment while supplying reactive silicate ions (SiO₃²⁻) to accelerate N-A-S-H gel and C-A-S-H gel formation. These findings offer guidance for optimizing CG-based cementitious formulations for formula optimization and large-scale utilization of CG cementitious materials. Full article

Background: Amorphous drug formulations are commonly used to improve the solubility and bioavailability of poorly soluble molecular pharmaceuticals, yet less is known about their molecular conformations and local bonding interactions than their crystalline phases. Methods: High-energy X-ray diffraction structure factor measurements have been made on liquid and glassy nifedipine (NIF), felodipine (FEL), NIF 1:3 polyvinylpyrrolidone (PVP), and FEL 1:3 PVP wt.% mixtures. The corresponding X-ray pair distribution functions have been interpreted using empirical potential structure refinement using different models and density functional theory conformer calculations. Results: In both NIF and FEL, the NH···O inter-molecular hydrogen bonds between the pyridyl nitrogen and ester carbonyls are found to be considerably weaker than those observed in the crystalline polymorphs. For nifedipine, it is proposed that either inter-molecular NH…ON nitro bonds are present and/or a fraction (<20%) of conformational changes, with the aryl ring flipped, occur in the liquid state. For felodipine, the models indicate significant disorder associated with the methyl and ethyl side chains in the liquid state, with the main peak intensity at 3.0 Å arising from intra-molecular Cl-Cl atom pairs. When nifedipine molecules are incorporated into PVP, our models show they possess stronger NH···O bonds to the PVP polymer than felodipine molecules, which have stronger affinity for bonding to the polymer than to other felodipine molecules. Conclusions: The amorphous forms of both NIF and FEL show much weaker hydrogen bonding than found in their crystalline phases. Liquid NIF also exhibits configurations which are not observed in the crystal phases. Full article

Leucomisine is a major component of renewable plant raw material Artemisia leucodes Schrenk, a sesquiterpene γ-lactone exhibiting antioxidant, hypoglycemic, antiparasitic, and hepatoprotective activities. However, the use of leucomisine in pharmaceuticals is limited by its insufficient bioavailability associated with low aqueous solubility. Therefore, the effect of solid-state synthesis based on leucomisine using the methods of “solvent removal”, “simple mixing”, and “mixture heating”, with disodium glycyrrhizinate as a carrier, on the aqueous solubility of leucomisine was investigated. It was established that the synthesized solid dispersions exhibit increased solubility (7–19-fold) and dissolution rate (36–100-fold) of leucomisine released from the carrier. The most pronounced stimulation of the dissolution process was observed for samples obtained using the “simple mixing” method. Based on physicochemical studies (visible-range spectrophotometry, microcrystalloscopy, investigation of optical properties of solutions, and X-Ray phase analysis), it was determined that the enhancement of solubility is attributed to the loss of crystalline state, micronization, and the solubilization process of leucomisine by the carrier, as well as to the formation of a colloidal solution of leucomisine stabilized by disodium glycyrrhizinate. Full article

To address inherent limitations of chitosan-based edible films, including inadequate mechanical strength and poor moisture resistance, cellulose nanofibers (CNF) were employed as a synergistic film-forming component to partially substitute chitosan in the fabrication of ternary composite films (denoted as CSTF-CNFs). This approach was based on a previously developed chitosan matrix modified with tannin-Fe³⁺ nanoparticles (TF). It was hypothesized that CNF could function as a reinforcing scaffold to improve the dispersion of TF within the film matrix and, through hydrogen bonding and physical entanglement, form an interpenetrating fiber network with chitosan, thereby enhancing the structural and barrier properties of the films. The present study systematically evaluated the influence of varying CNF substitution ratios (0–30%) on the physicochemical characteristics of the resulting composite films and their performance in tomato preservation. The results demonstrated that an appropriate CNF incorporation facilitated the formation of a dense, cross-linked network with chitosan and TF via hydrogen bond interactions, significantly improving both mechanical strength and water resistance. Among all formulations, the CSTF-CNF20 film exhibited optimal comprehensive performance, achieving the highest tensile strength of 27.60 MPa. Moreover, its swelling ratio markedly decreased from 675.5% (CSTF-CNF0) to 120.9%, while the water contact angle increased to 113.7°, and the DPPH radical scavenging activity remained above 85%. Tomato preservation assays revealed that, in comparison with the untreated control and polyethylene film-wrapped groups, the application of CSTF-CNF20 coating effectively mitigated the decline in weight loss and firmness, preserved surface color integrity, and resulted in the highest L* value alongside the lowest soluble solids content. These findings suggest that the synergistic integration of CNF with nano-scale metal–phenolic networks offers a viable strategy for developing high-performance chitosan-based edible films. The CSTF-CNF20 composite film holds significant promise for application in the postharvest preservation of fruits and vegetables. Full article

This study presents an experimental investigation of the influence of dopant type and calcination temperature on BaTiO₃-based piezoceramics synthesized by a solid-state calcination process. The effects of Mn, Nb, La, and Ce dopants on the structural, morphological, and piezoelectric characteristics of powders calcined at 1000 °C and 1100 °C were systematically evaluated. In addition, two co-doped BaTiO₃ compositions, namely Mn–Nb and La–Nb, calcined at 1000 °C, were investigated in order to assess the combined effect of acceptor–donor and donor–donor doping strategies on microstructural evolution and structural stability. The synthesized powders were characterized by scanning electron microscopy (SEM), particle size analysis, energy-dispersive X-ray spectroscopy (EDS), elemental mapping, and X-ray diffraction (XRD), in comparison with a commercial BaTiO₃ reference powder. The piezoelectric response was assessed by correlating the structural modifications induced by doping with the estimated piezoelectric coefficient d₃₃, calculated as a function of the tetragonality ratio (c/a) and further correlated with the crystallite size. The results reveal significant variations in grain growth, dopant distribution, and crystallographic stability, highlighting the critical role of dopant chemistry and calcination temperature in tailoring the functional properties of BaTiO₃ for piezoelectric applications. Full article

Electric discharge cavitation is an effective method for water treatment that combines physical and chemical effects within a single process. It enables water disinfection, extraction acceleration, dispersion of solid particles, and enhancement of porous material permeability. Compared to conventional chemical treatment, it reduces the demand for reagents and minimizes secondary pollution. This new and developing technology significantly contributes to the preservation of natural aquatic ecosystems by providing a sustainable alternative to traditional decontamination methods, thereby reducing the overall anthropogenic pressure on the environment. This study focuses on developing a reliable method for assessing electric discharge cavitation intensity and controlling water purification processes. The proposed approach is based on the oxidation of iodide ions to molecular iodine by reactive species generated during electric discharge cavitation. The adapted iodometric method is sensitive, reproducible, and does not require complex optical or acoustic equipment. Experimental results confirmed that iodometry provides an accurate evaluation of cavitation intensity, allowing control of specific energy consumption and optimization of treatment parameters. Optimal operating conditions were established to control the water processing by electric discharge cavitation: stainless-steel electrodes, specific input energy not exceeding 280 kJ·L⁻¹, the presence of a free liquid surface in the working chamber, and a discharge pulse frequency below 10 Hz. The proposed method supports the development of energy-efficient, low-waste technologies for wastewater and natural water treatment and facilitates the integration of electric discharge systems into existing water treatment infrastructure, particularly under resource-limited conditions. Full article