Energy Dispersive X-ray Spectroscopy Research Articles

Influence of inclusions on the pitting behavior of cast duplex stainless steels and patch weld layers

Abstract The relationship between the corrosion resistance of cast duplex stainless steel welded joints and inclusions was investigated by metallographic characterization, electrochemical tests, in-situ tests, scanning electron microscopy (SEM) combined with energy dispersive X-ray spectrometry (EDS) and other methods. The results showed that inclusions were the main sites for pitting corrosion initiation in cast 2205 welded joints, and the MnS portion of the composite inclusions preferentially dissolved to form micro-pits, which triggered pitting corrosion. In addition, the density of inclusions in the heat-affected zone (HAZ) was high and the average size of inclusions was larger, resulting in poorer pitting resistance in the HAZ. And pitting was more likely to occur and subsequently a large pit was developed which ultimately leads to failure.

Mechanical properties of (Ba0.4Sr0.4Ca0.2Fe12O19)x/(Bi1.6, Pb0.4)-2223 composite impacted in seawater

In the present work, the effect of adding Ba0.4Sr0.4Ca0.2Fe12O19 hard nanoparticles and the immersion in seawater for different durations (0, 2, 6, 12, and 24 h) on the mechanical characteristics of the Bi, Pb-2223 superconductor phase were studied. A conventional solid-state reaction method was used to produce the (Ba0.4Sr0.4Ca0.2Fe12O19)x/(Bi1.6, Pb0.4)-2223 composites (0.00 ≤ x < 0.40 wt%). X-ray diffraction (XRD) confirmed the primary phase formation of the tetragonal (Bi1.6, Pb0.4)-2223. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) studies were also carried out to demonstrate the microstructural analyses of the samples during seawater immersion. Compared to the pure (Bi1.6, Pb0.4)-2223 phase, SEM and EDX verified the improvement of the adsorption of seawater elements upon adding the nanoparticles. This resulted in faster grain size reduction in the (Bi1.6, Pb0.4)-2223 phase than in the pure sample before immersion. Vickers microhardness () Measurements were performed for 30 s at room temperature, with applied stresses ranging from 0.49 to 9.80 N after immersion in the seawater for different durations (0, 2, 6, 12, and 24 h). For the sample with x = 0.04 wt%, values enhanced with percentages of 67.72% and 98.44%, before and after immersion in seawater for 24 h, respectively. This suggests that the mechanical properties of the (Bi1.6, Pb0.4)-2223 phase were enhanced by a small addition of these nanoparticles and the salts of seawater adsorbed on the sample’s surface. The modified proportional sample resistance (MPSR) model offered the most accurate theoretical analysis in the plateau limit region, before and after seawater immersions, with a less than 5% variance. Furthermore, the incorporation of Ba0.4Sr0.4Ca0.2Fe12O19 into the superconductor had a positive impact on several mechanical characteristics, including fracture toughness (K), yield strength (Y), and elastic modulus (E). All these mechanical parameter values followed the same trend, increasing with the increase in immersion time. However, they are at their height with the presence of 0.04 wt% of these nanoparticles. The toughness increased by 27.31% of the pure sample at this point. After that, when the immersion time rose from 0 to 24 h, this number increased by 42.59%.

Porosity and mineralogy in the Lajas tight gas sandstone reservoir, Neuquén Basin, Argentina

ABSTRACT In specific subsurface conditions, the sandstones of the Lajas Formation represent a tight gas reservoir in a deltaic mouth-bar system. Therefore, understanding the diagenetic processes that affected these sandstones is a first step towards reservoir quality prediction and production optimization.14C-PMMA autoradiography can be used to characterize the porosity distribution at centimeter-to-micrometer scales. The mineral phases can be associated with specific porosities using scanning electron microscopy (SEM) in the backscattered-electron imaging mode (BSEi) and can be combined with elemental mapping using energy-dispersive X-ray spectroscopic (EDS) analysis. For bulk analysis, porosity mapping is useful for characterizing the constrictivity and the tortuosity of the porous network created by the geological processes related to the basin’s evolution (e.g., compaction, dissolution, fracturing, cataclasis). 14C-PMMA autoradiography offers a reliable porosimetry method which is adaptable to most rocks. In our study, the superimposition of porosity maps and mineral maps revealed that: 1) secondary porosity, deriving from feldspar dissolution in medium- to coarse-grained sandstone, and the varying degree of dissolution are both influenced by grain size and degree of cementation, 2) mudstone rip-up clasts have homogeneous porosities (3–4%), 3) the host rock’s porosity varies widely (1–8%), 4) bioturbated siltstone and sandstone present higher porosities within the trace fossils, mainly associated with organo-pores (primary porosity in the organic matter), mineral formation (pyrite precipitation), and clay development (microporosity). Integrating these petrophysical and mineralogical observations with the interpretation of the sedimentary and structural processes that affected the lithologies analyzed allows the following generalizations: 1) the highest porosity and permeability occur in samples representing high-energy environments of deposition (deltaic channel infills and mouth bars), 2) deformation bands cannot be considered fairways for fluid migration, as they have a lower porosity than the sandstone matrix, mainly because dilational shear bands underwent cementation and compactional shear bands underwent cataclasis.

Use of Modified Activated Carbon in Groundwater Remediation for Human Consumption

This study aimed to produce activated carbon from desilicated rice husks using various carbonization and activation methods, including a tube furnace, muffle furnace, and artisanal pyrolysis. The resulting activated carbons were characterized for their adsorptive capacity through the determination of iodine number and methylene blue adsorption; these are key indicators of specific surface area and adsorbent quality. Advanced characterization techniques were employed, such as scanning electron microscopy (SEM), which revealed a highly porous and irregular surface structure, and energy dispersive X-ray spectroscopy (EDS), confirming the effective removal of impurities and optimization of the elemental composition. Atomic force microscopy (AFM) demonstrated favorable surface roughness for adsorption processes. Among the samples, CaDH162-CADH53 exhibited the highest performance, with an iodine number of 1094.8 mg/g and a yield of 93.5%, signifying a high adsorption capacity. The activation treatments with phosphoric acid and calcium carbonate significantly improved the porous structure, further enhancing the material’s adsorptive properties. In conclusion, the activated carbons produced in this study demonstrated optimal physicochemical properties for water purification and contaminant treatment applications. These findings highlight the potential of using agricultural waste, such as rice husk, as a sustainable and scalable alternative for industrial-scale activated carbon production.

3D Vertical Ferroelectric Capacitors with Excellent Scalability.

Three-dimensional vertically stacked memory is more cost-effective than two-dimensional stacked memory. Vertically stacked memory using ferroelectric materials has great potential not only in high-density memory but also in neuromorphic fields because it secures low voltage and fast operation speed. This paper presents the implementation of a ferroelectric capacitor comprising a vertical two-layer stacked structure composed of a titanium nitride (TiN)/aluminum-doped hafnium oxide/TiN configuration. To enhance the ferroelectric properties influenced by the active area, we propose a structure in which multiple small holes share a common pillar electrode. Comprehensive analyses using transmission electron microscopy and energy-dispersive X-ray spectroscopy were conducted to confirm the chemical composition and physical structure of the device. This newly engineered architecture demonstrated promising characteristics, including a sufficient remnant polarization, small device-to-device variations, high endurance, and excellent retention in 3D vertical structures. Moreover, this structure can be applied to one-transistor n-capacitor ferroelectric random access memory with a vertical transistor.

Characterization, Bioactive Profiling and Evaluation of the Pharmacological Activities of Ethanol Extract of Lannea welwitschii (Hiern) Engl.

Introduction: Lannea welwitschii is a medicinal plant used in traditional medicine to treat various infectious diseases due to its plethora of bioactive compounds that possess various pharmacological activities. This study aimed to characterize and determine the phytochemical profile and the bioactive compounds responsible for their pharmacological activities. Methods: Phytochemical screening and Gas-Chromatography Mass Spectrometry (GC-MS) analysis were carried out on the ethanolic extract of L. welwitschii to determine the volatile compounds present. Characterization of the crude extract was carried out using Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Energy Dispersive X-ray spectroscopy (EDX). The antioxidant potential of the extract was evaluated using methods such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric-reducing antioxidant Potential (FRAP). The antibacterial activities were determined using the macro-broth dilution technique. Results: Secondary metabolites such as saponins, tannins, alkaloids, reducing sugars, and cardiac glycoside were identified. The GC-MS analysis showed the presence of 48 bioactive compounds, out of which 12 had peak area percentages ≥ 1%. Some of the bioactive compounds identified include 2-butoxy-ethanol, Dodecanoic acid, Stigmasterol, Isopropenyl, and n-hexadecanoic acid, which have been reported with different biological activities. FTIR analysis revealed the presence of various functional groups which showed major compounds in the plant extract. The morphological features showed the spherical shape of the plant extract with several aggregates, while the EDX analysis identified elements such as silicon, oxygen, and silver. The extract demonstrated inhibitory potential against some of the bacterial isolates. However, Bacillus pumilus, Klebsiella quasipneumoniae, Klebsiella aerogenes, and Staphylococcus aureus are more susceptible with MIC of 0.313 and 0.625 mg/ml respectively. Conclusion: The presence of secondary metabolites and bioactive compounds revealed by the characterization and phytochemical analysis provided enough evidence for the usage of the plant in the treatment of infectious diseases and thus might be considered a therapeutic agent.

Advanced Solid Lubrication with COK-47: Mechanistic Insights on the Role of Water and Performance Evaluation.

Metal-organic framework (MOF) nanoparticles have attracted widespread attention as lubrication additives due to their tunable structures and surface effects. However, their solid lubrication properties have been rarely explored. This work introduces the positive role of moisture in solid lubrication in the case of a newly described Ti-based MOF (COK-47) powder. COK-47 achieves an 8.5-fold friction reduction compared to AISI 304 steel-on-steel sliding under room air. In addition, COK-47 maintains a similarly low coefficient of friction (0.1-0.2) on various counterbodies, including Al2O3, ZrO2, SiC, and Si3N4. Notably, compared to other widely studied MOFs (ZIF-8, ZIF-67) and 2D materials powder (MXene, TMD, rGO), COK-47 exhibits the lowest friction (≈0.1) under the same experimental settings. Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscope, and transmission electron microscopy indicate that the tribofilm is an amorphous film obtained by hydrolysis of COK-47 in the air with moisture. Density functional theory further confirms that water catalyzes the decomposition of COK-47, a crucial step in forming the tribofilm.This study demonstrates the idea of utilizing MOF and water-assisted lubrication mechanisms. It provides new insights into MOF applications in tribology and highlights interdisciplinary contributions of mechanical engineering and chemistry.

Evaluation of the Effect of Different Universal Adhesives on Remineralized Enamel by Shear Bond Strength and Fe-SEM/EDX Analysis

The aim of this study is to evaluate the shear bond strength of different universal adhesives applied to intact, demineralized, and remineralized enamel surfaces with total-etch and self-etch modes and to examine the effect of universal adhesives on the Ca/P mineral atomic and mass ratios of these enamel with FE-SEM/EDX (Field Emission Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy) analysis. For this study, 264 bovine incisors were used. Samples in the demineralized and remineralized groups were kept in demineralization solution at 37 °C for 96 h to make an artificial initial carious lesion. After demineralization, half of the demineralized samples were remineralized with MI Paste Plus. For shear bond strength (n = 144) and FE-SEM/EDX analysis (n = 120), G-Premio Bond and Clearfil S3 Bond Universal were applied on enamel surfaces with total-etch and self-etch modes, and bond strength samples were restored with resin composite. All samples were tested. The results were evaluated statistically by a three-way ANOVA test. The shear bond strength of the remineralized enamel showed high bond strength values comparable to intact enamel for universal adhesive systems. The Ca/P mineral atomic and mass ratios in remineralized enamel showed higher values than demineralized enamel, similar to intact enamel for universal adhesive systems. Initial carious lesion surfaces are unsuitable enamel surfaces for restoration. The remineralization of this surface layer before adhesive procedures may positively affect bond strength.

Hybrid Analysis of Biochar Production from Pyrolysis of Agriculture Waste Using Statistical and Artificial Intelligent-Based Modeling Techniques

Biochar is gaining recognition as a sustainable material, with several applications in soil amendment, carbon sequestration, nutrient dynamics, the remediation of organic contaminants from soil, and water filtration. However, understanding its characteristics is limited due to its intricate structure. This study used response surface methodology (RSM) and artificial neural networks (ANNs) to optimize and predict the production of biochar from the pyrolysis of palm kernel shells. To determine how residence time, nitrogen flow rate, and pyrolysis temperature affected biochar production, a Box–Behnken experimental design was employed. The prediction of the biochar yield was modeled using four different models of ANNs: narrow, medium, wide, and optimum. The physicochemical properties of the biochar produced at pyrolysis temperatures ranging from 400 to 800 °C were determined using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), nitrogen (N2) physisorption analysis, and field emission scanning electron microscopy (FESEM). With a p-value significantly lower than 0.05, the response surface quadratic model was found to be the most suitable to optimize the biochar yield obtained from the PKS pyrolysis. Biochar production was very sensitive to the three operating parameters: pyrolysis temperature, nitrogen flow rate, and pyrolysis time. With a coefficient of determination (R2) of 0.900, root mean square error (RMSE) of 0.936, and mean absolute error (MAE) of 0.743, the optimized ANN outperformed the other three ANN models tested. When compared to the optimized ANN, the response surface quadratic model with an R2 of 0.989 had better prediction of biochar yield. At optimized experimental conditions for nitrogen flow rate (150.01 mL/min), temperature (799.71 °C), and pyrolysis time (107.61 min), a biochar yield of 37.87% was obtained at a desirability function of 1.

Efficient adsorptive removal of Congo Red dye using activated carbon derived from Spathodea campanulata flowers

This report investigates the preparation, characterization, and application of activated carbon derived from Spathodea campanulata flowers (SCAC) to remove Congo Red (CR) dye from aqueous streams. SCAC was synthesized using orthophosphoric acid activation which yielded a mesoporous material with a specific surface area of (986.41 m2/g), significantly exceeding values reported for flower-derived activated carbons in the available literature. Field emission scanning electron microscopy (FESEM) image revealed an irregular, rough surface morphology pre-adsorption, which became smoother post-adsorption, indicating successful CR attachment. Elemental analysis through energy-dispersive x-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) confirmed an increase in carbon content and the appearance of sulfur, verifying CR uptake. Adsorption kinetics obeyed the pseudo-second-order equation, signifying chemisorption, while the equilibrium dataset fitted better to the Langmuir model, with R2 of 0.9944, suggesting a monolayer adsorption mechanism with a maximum adsorption capacity of 59.27 mg/g. Thermodynamic analysis revealed spontaneous and endothermic adsorption process. Desorption studies showed methanol as the most effective desorbing agent, with SCAC retaining considerable adsorption capacity across six cycles, highlighting its reusability. In tests with real water matrices, SCAC demonstrated significantly higher removal efficiency in natural waters than control, suggesting enhanced adsorption in complex matrices. These findings underscore the practical applicability of SCAC in real-world wastewater treatment, offering a promising solution for large-scale industrial applications.

Influence of Fiber Direction on the Tribological Behavior of Carbon-Reinforced PEEK at Elevated Temperature for Application in Gas Turbine Engines

Abstract The aerospace industry aims for net-zero greenhouse gas emissions by 2050, requiring gas turbine engines to reduce CO2 emissions. This will impact engine material selection due to harsher operating conditions, limiting traditional metal/alloy use. While fiber-reinforced polymer (FRP) composites are commonly used in the aerospace industry, their use in gas turbine engines is often restricted by the lower operating temperatures of the polymer matrix. However, many studies have demonstrated the tribological potential of FRP in the fan section of the engines, but little attention has been given to the potential of orienting the fibers in the normal (i.e., out-of-plane) direction relative to the wear surface to leverage the anisotropic properties of FRP composites. This study investigates the impact of fiber orientation on the tribological properties of carbon fiber/polyetheretherketone (PEEK) (CF-PEEK) at elevated temperatures. Three CF-PEEK samples with different fiber orientations were selected for this study (parallel, antiparallel, and normal directions), as well as a fourth sample of pure PEEK. Tribological tests were conducted using a ball-on-disk tribometer at an elevated temperature of 200 °C to evaluate wear and friction behavior. The worn surfaces and counterfaces were analyzed using confocal laser scanning microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The findings reveal that CF-PEEK with fibers oriented in the normal direction demonstrates significantly enhanced tribological performance at elevated temperatures, achieving a 95% reduction in the friction coefficient and a 92% decrease in the wear-rate compared to pure PEEK. A wear mechanism has been proposed to explain the superior wear resistance of normally oriented fibers in CF-PEEK, linking it to the development of a fiber-based interface during the run-in phase and the formation of a uniform transfer film.

Solid-State Reaction Synthesis of CoSb2O6-Based Electrodes Towards Oxygen Evolution Reaction in Acidic Electrolytes: Effects of Calcination Time and Temperature

Mitigating global warming necessitates transitioning from fossil fuels to alternative energy carriers like hydrogen. Efficient hydrogen production via electrocatalysis requires high-performance, stable anode materials for the oxygen evolution reaction (OER) to support the hydrogen evolution reaction (HER) at the cathode. Developing noble metal-free electrocatalysts is therefore crucial, particularly for acidic electrolytes, to avoid reliance on scarce and expensive metals such as Ir and Ru. This study investigates a low-cost, solvent-free solid-state synthesis of CoSb2O6, focusing on the influence of calcination time and temperature. Six samples were prepared and characterized using powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDX), Brunauer–Emmett–Teller (BET) analysis, field-emission scanning electron microscopy (FESEM), and electrochemical techniques. A non-pure CoSb2O6 phase was observed across all samples. Electrochemical testing revealed good short-term stability; however, all samples exhibited Tafel slopes exceeding 200 mV dec−1 and overpotentials greater than 1 V. The sample calcined at 600 °C for 6 h showed the best performance, with the lowest Tafel slope and overpotential, attributed to its high CoSb2O6 content and maximized {110} facet exposure. This work highlights the role of calcination protocols in developing Co-based OER catalysts and offers insights for enhancing their electrocatalytic properties.

Pick-and-Place Transfer of Arbitrary-Metal Electrodes for van der Waals Device Fabrication.

Van der Waals electrode integration is a promising strategy to create nearly perfect interfaces between metals and 2D materials, with advantages such as eliminating Fermi-level pinning and reducing contact resistance. However, the lack of a simple, generalizable pick-and-place transfer technology has greatly hampered the wide use of this technique. We demonstrate the pick-and-place transfer of prefabricated electrodes from reusable polished hydrogenated diamond substrates without the use of any sacrificial layers due to the inherent low-energy and dangling-bond-free nature of the hydrogenated diamond surface. The technique enables transfer of arbitrary-metal electrodes and an electrode array, as demonstrated by successful transfer of eight different elemental metals with work functions ranging from 4.22 to 5.65 eV. We also demonstrate the electrode array transfer for large-scale device fabrication. The mechanical transfer of metal electrodes from diamond to van der Waals materials creates atomically smooth interfaces with no interstitial impurities or disorder, as observed with cross-section high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy. As a demonstration of its device application, we use the diamond transfer technique to create metal contacts to monolayer transition metal dichalcogenide semiconductors with high-work-function Pd, low-work-function Ti, and semimetal Bi to create n- and p-type field-effect transistors with low Schottky barrier heights. We also extend this technology to air-sensitive materials (trilayer 1T' WTe2) and other applications such as ambipolar transistors, Schottky diodes, and optoelectronics. This highly reliable and reproducible technology paves the way for new device architectures and high-performance devices.

Sustainable Removal of Phenol from Aqueous Media by Activated Carbon Valorized from Polyethyleneterephthalate (PET) Plastic Waste

PET, one of the most commonly used plastics, presents significant environmental challenges due to its non-biodegradable nature. To address this, we developed a sustainable method to convert PET waste into high-performance activated carbon via chemical activation with phosphoric acid (H3PO4). The produced activated carbon was analyzed utilizing X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), nitrogen adsorption/desorption (BET), energy-dispersive X-ray (EDX), and Raman spectroscopy. The activated carbon produced had a macroporous architecture with a substantial surface area, pore diameter, and pore volume of 655.59 m2/g, 3.389 nm, and 0.120 cm3/g, respectively. The adsorption isotherm of activated carbon for phenol conformed to the Langmuir model, signifying single-layer adsorption with a maximal capacity of 114.94 mg/g, while the kinetic adsorption adhered to the second-order model at an optimal pH of 7. The study highlights the sustainable benefits of mitigating plastic waste pollution while producing a cost-effective and eco-friendly adsorbent for water treatment applications. This research underscores the potential for recycling PET waste into valuable materials for environmental remediation.

Suppression of mycotoxins production and efficient chelation of heavy metals using natural melanin originated from Aspergillus flavus and Aspergillus carbonarius

BackgroundThis study employed melanin synthesized by Aspergillus flavus and Aspergillus carbonarius to inhibit the production of mycotoxins and bioremediation of heavy metals (HMs).MethodsFirst, twenty fungal isolates were obtained from soil samples, and were evaluated to produce melanin. The melanin of the most potent producers has undergone several confirmatory experiments, including, Dihydroxyphenylalanine (DOPA)-inhibitor-kojic acid pathway detection, High-performance liquid chromatography (HPLC), Fourier-transform infrared (FTIR) and Nuclear magnetic resonance (NMR). Additionally, the melanin production culture conditions were optimized. The antioxidant activity of melanin was detected with 1,1-Diphenyl-2-picrylhydrazyl (DPPH). HPLC was used to measure the mycotoxins produced in culture media supplemented with melanin. Molecular docking study investigated molecular interactions between melanin and mycotoxins through in silico approaches. FTIR and Energy-dispersive X-ray spectroscopy (EDX) were utilized to determine the percentage of melanin-chelated HMs, and an atomic absorption spectrophotometer (AAS) was used to detect HMs removal efficiency.ResultsThe melanin-enriched medium (0.3% and 0.4%) exhibited complete inhibition of aflatoxin B1 (AF-B1) by A. flavus and ochratoxin A (OTA) by A. carbonarius, respectively. Furthermore, melanin showed effective HM removal efficiency, increasing with melanin concentration. The removal efficiency of Cd+2 and Cr+6 by 1 mg/mL melanin was 49% and 63%, respectively. When the concentration of melanin was increased to 15 mg/mL, the removal efficiency of Cd+2 and Cr+2 increased to 60% and 77%, respectively.ConclusionThe study exhibited a natural approach for melanin production, using melanin as a heavy metal-chelating agent and capability to inhibit the production of aflatoxin B1 and ochratoxin A. Further, the study provides significant evidence regarding the bioremediation pipeline, for melanin production through biotechnological processes by filamentous fungi.

Electro-Oxidation of Glycerol on Core–Shell M@Pt/C (M = Co, Ni, Sn) Catalysts in Alkaline Medium

This study explores the development of core–shell electrocatalysts for efficient glycerol oxidation in alkaline media. Carbon-supported M@Pt/C (M = Co, Ni, Sn) catalysts with a 1:1 atomic ratio of metal (M) to platinum (Pt) were synthesized using a facile sodium borohydride reduction method. The analysis confirmed the formation of the desired core–shell structure, with Pt dominating the surface as evidenced by energy-dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) revealed the presence of a face-centered cubic (fcc) Pt structure for Co@Pt/C and Ni@Pt/C. Interestingly, Sn@Pt/C displayed a PtSn alloy formation indicated by shifted Pt peaks and the presence of minor Sn oxide peaks. Notably, no diffraction peaks were observed for the core metals, suggesting their amorphous nature. Electrocatalytic evaluation through cyclic voltammetry (CV) revealed superior glycerol oxidation activity for Co@Pt/C compared to all other catalysts. The maximum current density followed the order Co@Pt/C &gt; Ni@Pt/C &gt; Sn@Pt/C &gt; Pt/C. This highlights the effectiveness of the core–shell design in enhancing activity. Furthermore, Sn@Pt/C displayed remarkable poisoning tolerance attributed to a combined effect: a bifunctional mechanism driven by Sn oxides and an electronic effect within the PtSn alloy. These findings demonstrate the significant potential of core–shell M@Pt/C structures for designing highly active and poisoning-resistant electrocatalysts for glycerol oxidation. The presented approach paves the way for further development of optimized catalysts with enhanced performance and stability aiming at future applications in direct glycerol fuel cells.

Impact of vial quality on interactions, particle formation, container closure integrity, and gas permeability for frozen drug product storage.

The frozen storage of biopharmaceuticals brings new challenges to the primary packaging material. Due to an increasing demand and the downsides of standard type I glass vials, such as vial breakage, novel vial types for special applications of parenteral drug products have been introduced to the market in the past years. Mechanical stresses due to dimensional changes experienced during freezing and thawing could change the material properties, hence affecting the interaction with the drug product stored in the vial or functionality such as overall integrity. Therefore, we studied the suitability of different vial qualities related to the thermally induced mechanical stresses experienced during frozen drug product preparation and storage. First, the possible failure modes for each vial type were identified. The interaction between vial surface and drug product were investigated considering surface hydrophobicity, surface free energy and surface roughness as well as microscopically visible changes analyzed by confocal laser scanning microscopy. Differences in surface hydrophobicity, roughness and surface free energy between the vial types did not impact the performance upon freeze-thaw stress and did not change with the stress. Screening the vial content for particles originating from the container using light and electron scanning microscopy combined with energy-dispersive X-ray spectroscopy showed only rare cases of particles in coated glass vials. Under extreme stress conditions, including a drop-test in the frozen state, a low number of particles was also detected in coated polymer vials. No quality issues regarding the functionality were observed upon container closure integrity testing, while the oxygen permeability was slightly increased for uncoated and especially coated polymer vials. Overall, the results show that several vial types are appropriate for the frozen storage of drug products and selection should be based on the formulation and other product requirements.

Effectively eliminating lead and cadmium from industrial wastewater using a biowaste-based sorbent

Toxic heavy metals, such as Pb(II) and Cd(II), pose serious environmental and health risks, stressing the urgent demand for innovative and sustainable techniques to reduce their adverse effects. This study investigates the use of sugar beet biowaste as an eco-friendly biosorbent for the removal of Pb(II) and Cd(II) from aqueous solutions, in both laboratory and industrial effluents. Characterization through scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy revealed the formation of stable hydrocerussite and otavite, confirming chemisorption. Approximately 95% of the employed biowaste is composed of calcium (Ca), carbon (C), and oxygen (O). The zeta potential was measured at − 17.5 mV with a point of zero charge at pH 8.0, and the total surface area of the biosorbent was approximately 7.72 m2 g−1, with a Langmuir surface area of 11.563 m2 g−1 and a pore volume of 0.028 cm3 g−1. Various parameters, such as the metal concentration, biosorbent dosage, pH, temperature, and contact time, were optimized, achieving maximum removal of Pb(II) and Cd(II) within 60 min at pH 12 and 328 K. Sorption followed a pseudo-second-order kinetic model (R2 = 0.99) and the Freundlich isotherm (R2 = 0.98), with high sorption capacities of 466.5 mg g−1 for Pb(II) and 505.6 mg g−1 for Cd(II). Thermodynamic analysis indicated that the sorption process is spontaneous, thermodynamically favorable, and endothermic. The biowaste effectively removed heavy metals and demonstrated removal efficiencies exceeding 85% for most heavy metals in industrial effluent samples from Alexandria and Ain Sokhna. Sorption capacity ratio values close to 1 indicate effective Pb(II) and Cd(II) uptake with minimal interference, even in the presence of methylene blue dye. Comparative analysis revealed that the untreated biosorbent was more efficient than typical biosorbents, and an economic cost evaluation revealed that processing the biosorbent costs 1.05 USD/kg, highlighting its potential as a sustainable and economically viable option for industrial effluent treatment and supporting broader environmental goals.

Immobilization of 4-MBA & Cu2+ on Au nanoparticles modified screen-printed electrode for glyphosate detection.

This study introduces an innovative electrochemical biosensor, engineered through the functionalization screen-printed electrode (SPE) with a coordination complex comprised of 4-mercaptobenzoic acid (4-MBA) and copper ions (Cu2+), achieving precise quantitative determination of glyphosate. Electrodepositing gold nanoparticles (AuNPs) onto the electrode surface, forming a self-assembled monolayer (SAM) of 4-MBA via thiol-gold interactions, and immobilizing Cu2+ via coordination bonding with the monolayer, finalizing the electrochemical biosensor construction as Cu2+/4-MBA/AuNPs/SPE. The successful modification of the biosensor interface is confirmed through scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and electrochemical characterization. Through parameter optimization, critical metrics for the biosensor preparation process have been determined. Using square wave voltammetry (SWV), a linear relationship between the glyphosate concentration and the peak current inhibition ratio at the electrode surface is established. Additionally, the repeatability and anti-interference capabilities of the fabricated biosensors are evaluated. The experimental outcomes affirm the biosensor's capability for quantitative glyphosate detection across a 5-100nM range, boasting a 1.65nM limit of detection (LOD). Testing on tap water samples verifies a robust recovery rate for glyphosate residues, spanning 89.84%-107.48%. The proposed biosensor holds significant promise for glyphosate detection, offering substantial applicability and this study provides a valuable reference for the advancement of biosensors geared toward the quantitative assessment of organophosphate pesticides (OPs).

Flexible and lead-free polymer composites for X-ray shielding: comparison of polyvinyl chloride matrix filled with nanoparticles of tungsten oxides.

Polymer nanocomposites have been investigated as lightweight and suitable alternatives to lead-based clothing. The present study aims to fabricate flexible, lead-free, X-ray-shielding composites using a polyvinyl chloride (PVC) matrix and different nanostructures. Four different nanostructures containing impure tungsten oxide, tungsten oxide (WO3), barium tungstate (BaWO4), and bismuth tungstate (Bi2WO6) were synthesized through various methods. Subsequently, their morphological characteristics were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Also, energy-dispersive X-ray spectroscopy (EDS) analysis was performed to establish the presence of the filler in the PVC matrix. Two different weight ratios of these nanostructures (20% wt and 50% wt) were used to produce the PVC composites. To investigate attenuation parameters, the prepared composites were irradiated with X-rays at tube voltages of 40, 80, and 120kV. The results showed that the PVC composites containing 20% wt Bi2WO6 had the highest linear attenuation coefficient (µ) at all three voltages. Furthermore, they had the lowest half-value layer (HVL), tenth-value layer (TVL), and 0.5mm equivalent lead thickness values at each of the three voltages. The PVC composites containing 50% wt Bi2WO6 had attenuation coefficients greater than those reported for PbO at all three X-ray voltages. Among the studied tungsten nanostructures, bismuth tungstate had the best attenuation performance for X-ray protection. Additionally, this composite is light, flexible, and non-toxic, making it a promising alternative to lead aprons.