Energy Dispersive X-ray Research Articles

The influence of thermal tempering on the fracture resistance, surface microstructure, elemental surface composition, and phase analysis of four heat-pressed lithia-based glass ceramic crowns

Abstract Background This in-vitro study aimed to evaluate the impact of thermal tempering and ceramic type on the fracture resistance, surface microstructure, elemental surface composition and phase analysis of four heat-pressed glass ceramics. Methods A total of 84 glass-ceramic crowns were pressed and randomly allocated into four equal groups (n = 21) according to the ceramic type: Group (E): IPS e.max Press, Group (L): GC initial LiSi Press, Group (C): Celtra Press and Group (A): VITA Ambria. The crowns of each group were equally allocated into three subgroups (n = 7) regarding the subsequent thermal tempering temperature. Subgroup (T0): No tempering. Subgroup (T1): Tempering at 9% below pressing temperature. Subgroup (T2): Tempering at 5% below pressing temperature. Samples were tested for fracture resistance using a universal testing machine. A scanning electron microscope, X-ray diffraction, and Energy Dispersive x-ray analysis were utilized to disclose the microstructural features. Results When there is no tempering, IPS e.max press showed a significant elevated fracture resistance (P-value = 0.002). There was an insignificant difference between other ceramics. While with tempering (T2) as well as (T1), Lisi press (L) showed a significant elevated fracture resistance. There was an insignificant difference between other ceramics (P-value = 0.004). Conclusions Incorporation of zirconia oxide into the lithium disilicate glass matrix did not show improvement in the fracture resistance. Thermal tempering procedure had significant effect on fracture resistance. Thermal tempering technique had no influence the elemental surface composition and phase analysis yet T2 samples showed changes in crystal size and orientation.

Deterioration of White Tempera Mock-Ups Paints in a SO2-Rich Atmosphere

Historical tempera paints exposed to pollutant gases suffer chemical and mineralogical deterioration which manifests through physical changes. Knowledge about these changes is fundamental to develop strategies for preventive conservation of wall paintings. In this research, binary tempera mock-ups composed of calcite, gypsum or lead white mixed with a proteinaceous binder (i.e., egg yolk or rabbit glue) were exposed to an aging test by using SO2-rich atmosphere exposure to learn about the degradation mechanisms and forms related to the pigment–binder interaction. Reference (unaltered) and aged mock-ups were studied from a physical point of view, characterizing the morphological changes by using stereomicroscopy and profilometry, color variations by using spectrophotometry, gloss changes, and reflectance changes by using a hyperspectral camera. Also, mineralogical and chemical changes were studied by means of X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy. Egg-yolk-based paints showed higher chromatic changes than their counterparts made of rabbit glue binder. Also, sulfate and sulfite salts precipitated on the surface of the aged paints regardless of their binder, influencing the painting reflectance which subsequently increased. Egg-yolk-based mock-ups exhibited roughness increases while the rabbit-glue-based paints showed roughness reduction, with the exception of lead-white-based paints. Therefore, the important influence of the type of binder and the interaction between the binder and the pigment on the durability of tempera paints in atmospheres rich in SO2 was confirmed.

Assessment of bond strength and bioactivity on a prototype resin-based luting agent containing a novel bioactive monomer.

A prototype luting agent based on a resin composite containing a novel bioactive monomer (a calcium salt of 4-methacryloyloxyethyl trimellitate; CMET) was developed, and its shear bond strength to tooth materials (dentin and enamel) and bioactivity was compared with those of commercially available resin-based luting systems. Extracted bovine incisors were embedded in a mold with a potting material. The labial bonding surface of the embedded tooth was wet-ground using #400 silicon carbide abrasive paper until sufficient superficial enamel or dentin was exposed. The bonding and luting agents assessed included our experimental bonding agent and luting agent, Prime&Bond Universal, Calibra Ceram, Multilink Primer A + B, Multilink Automix, Panavia V5 Tooth Primer, Panavia V5, RelyX Universal Resin Cement, SA Luting Multi, and SpeedCem Plus. The experimental luting agent was a novel material containing CMET. Shear-bond-strength testing was performed at 0 and 5000 thermocycles. To evaluate the in vitro bioactivity, specimens were immersed in 22mL of simulated body fluid (SBF) at 37°C for 5days. Scanning electron microscopy combined with energy-dispersive X-ray spectroscopy was used to examine the chemical composition of the specimen surfaces after immersion in the SBF. In conclusion, the shear bond strength to dentin and enamel, and durability of the novel bonding and luting agents were similar to those of commercially available resin-based luting systems. Furthermore, the novel luting agent had bioactive potential.

Analysis of the adhesion structure between the cycloolefin polymer and the copper seed layer formed using medium-vacuum sputtering

We have developed a novel approach for the fabrication of 6G communication antenna substrates by directly sputtering a copper seed layer onto a resin with low dielectric properties and low adhesiveness, without relying on a metal adhesion layer such as titanium. This study presents a detailed analysis of the effects of two surface modification methods—vacuum ultraviolet (VUV) irradiation and oxygen plasma treatment—performed before sputtering the copper seed layer on the interfacial structure between a cycloolefin polymer (COP) film and copper plating layer. Using scanning transmission electron microscopy, energy-dispersive x-ray spectroscopy, and selected area electron diffraction, we confirmed that both surface modification methods promote the formation of polycrystalline Cu2O at the interface between the COP film and the copper plating layer. VUV irradiation enhances the smoothness of the COP surface, resulting in the uniform distribution of hydrophilic functional groups. These functional groups stably interact with the sputtered copper, leading to the oxidation of copper during annealing and the formation of a consistent Cu2O layer. In contrast, oxygen plasma treatment selectively etches regions of the COP surface with high oxygen affinity, creating fine structures and concentrating the hydrophilic functional groups in the recessed areas. After sputtering, copper interacts with these localized functional groups, and during annealing, limited diffusion causes the copper to oxidize and aggregates into a Cu2O particle structure. Thus, this study demonstrates that the structures of polycrystalline Cu2O formed at the interface vary depending on the surface modification methods and elucidates the mechanisms behind these differences through analysis of surface morphology and the distribution of functional groups induced by each method.

Photofixation Pd Functionalization of ZnO Thin Films for Efficient Photocatalytic Removal of Doxycycline Antibiotic in Aqueous Phase

In this work, we demonstrate the co-catalytic modification of ZnO films via the photodeposition of palladium (Pd) to enhance the photocatalytic degradation of doxycycline (DC). Pristine ZnO films were synthesized using a sol–gel method and deposited onto glass substrates via dip-coating. The films were subsequently modified with Pd through chemical photodeposition under UV light, which facilitated the photoreduction of an aqueous 5 × 10−3 M Pd2+ precursor. The influence of varying UV photodeposition doses (2.5, 5, and 10 J/cm2) on the morphology and chemical composition of the Pd-modified films was investigated to control Pd surface coverage and chemical state. Characterization techniques included scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). At low UV doses (2.5 J/cm2), approximately 1.6 at.% of Pd was photodeposited, primarily as PdO, while higher UV doses (5–10 J/cm2) increased the metallic Pd0 content. The photocatalytic degradation of DC was evaluated in both distilled and tap water, where Pd/ZnO films demonstrated significantly higher removal efficiency (40–380% higher) than pristine ZnO films, with those containing higher Pd0 levels exhibiting the greatest activity. Across all samples, removal efficiency in tap water was approximately double that in distilled water.

Source identification and characterization of water-insoluble single particulate matter in rainfall sequences

ABSTRACT Analysis of atmospheric pollutants in rainwater provides valuable information on the environmental impacts of both natural and anthropogenic pollution sources. Air pollution studies often show that particulate matter (PM) collection on filters is used for subsequent analysis. However, this approach can result in significant particle accumulation on filters and complicate their characterization by semi-quantitative analytical techniques. In this study, insoluble PM in sequentially collected rainwater samples was analyzed for particle size, morphology, and chemical composition. Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectrometry (EDS) and a particle size analyzer were used for these analyses. By combining SEM–EDS data with particle size distribution analyses, chemical composition findings, and upper atmosphere back-orbit modeling, specific sources of insoluble particles in rainwater were identified. In addition, rainwater samples were analyzed for pH, electrical conductivity, and major anions and cations. The pH values varied from 6.19 to 7.04, while the electrical conductivity values varied from 5.35 to 83.53 μS/cm. Among the major ions, relatively high concentrations of Ca2+, SO42−, and NO3− were detected, while F−, Mg2+, Na+, and Cl− were observed in lower concentrations. The contributions of sea salt were evidenced by the presence of Cl− and Na+ ions.

Silver Gelled Chitosan Films: Preparation, Inclusion of Sunflower Seed Oil, and Application in Bread Packaging

Abstract Silver gelled chitosan (CS-Ag) films with improved mechanical traits were prepared via a simple technique, which comprised freezing the CS solution, and then pouring the AgNO3 solution onto it. This resulted in the creation of uniform and mechanically stable CS-Ag films due to the slow diffusion of AgNO3 into the frozen solid CS. The films were characterized via scan electron microscopy (SEM) and energy-dispersive X-ray (EDX). Their antimicrobial and mechanical traits were inspected. The tensile strength (TS) of the 1.5% (w/w) AgNO3 processed CS-Ag films reached 22.42 ± 0.89 MPa and its elongation at break was 33.01 ± 2.67%. The water vapor transmission rate (WVTR) of this film was also inspected and it was 167.77 g/m2day. This value was reduced to 146.95 and 120.68 g/m2day, after the inclusion of sunflower seed oil (SFO) within the CS-Ag films at 5% and 8% (w/w), respectively, and this reflected the increased water resistance of the SFO-CS-Ag films. The inclusion of SFO at concentration ≥ 5% (w/w) also increased the films antimicrobial traits when Aspergillus and Rhizopus species were inspected. On the other hand, the TS of the SFO-CS-Ag films was reduced to 15.13 ± 1.61 MPa and 10.17 ± 0.77 MPa for the 5% and 8% SFO, respectively. Nonetheless, these values were still within 8.3–31.4 MPa TS range of the frequently utilized packaging material; low-density polyethylene. Thus, the 5% and 8% (w/w) SFO-CS-Ag films were utilized to package white bread. The 8% (w/w) SFO-CS-Ag film efficiently preserved bread as no fungal growth observed for 10 storage days.

Sustainable Geopolymer Tuff Composites Utilizing Iron Powder Waste: Rheological and Mechanical Performance Evaluation

Geopolymers are a sustainable alternative to Portland cement, with the potential to significantly reduce the carbon footprint of conventional cement production. This study investigates the valorization of industrial waste iron powder (IP) as a fine filler in geopolymers synthesized from volcanic tuff (VTF). Composites were prepared with IP substitutions of 5%, 10%, and 20% by weight, using sodium hydroxide and sodium silicate as alkaline activators. Microstructural and phase analyses were conducted using scanning electron microscope coupled with energy dispersive X-ray spectroscopy (SEM-EDS), X-ray fluorescence (XRF), X-ray diffraction (XRD), and differential scanning calorimetry (DSC), while rheological properties, compressive strength, and flexural strength were assessed. The impact of curing temperatures (25 °C and 80 °C) on mechanical performance was evaluated. Results revealed that air content increased to 3.5% with 20% IP substitution, accompanied by a slight rise in flow time (0.8–2 s). Compressive and flexural strengths at 25 °C decreased by up to 22.48% and 28.39%, respectively. Elevated curing at 80 °C further reduced compressive and flexural strengths by an average of 45.30% and 64.68%, highlighting the adverse effects of higher temperatures. Although these formulations are not suitable for load-bearing applications, the findings suggest potential for non-structural uses, such as pavement base layers, aligning with sustainable construction principles by repurposing industrial waste and reducing reliance on energy-intensive cement production.

Advancing Source Apportionment of Atmospheric Particles: Integrating Morphology, Size, and Chemistry Using Electron Microscopy Technology and Machine Learning.

To further reduce atmospheric particulate matter concentrations, there is a need for a more precise identification of their sources. The SEM-EDS technology (scanning electron microscopy and energy-dispersive X-ray spectroscopy) can provide high-resolution imaging and detailed compositional analysis for particles with relatively stable physical and chemical properties. This study introduces an advanced source apportionment pipeline (RX model) that uniquely combines computer-controlled scanning electron microscopy with computer vision and machine learning to trace particle sources by integrating single-particle morphology, size, and chemical information. In the evaluation using a virtual data set with known source contributions, the RX model demonstrated high accuracy, with average errors of 0.60% for particle number and 1.97% for mass contribution. Compared to the chemical mass balance model, the RX model's accuracy and stability improved by 75.6 and 73.4%, respectively, and proved effective in tracing Fe-containing particles in the atmosphere of a steel city in China. This study indicates that particle morphology can serve as an effective feature for determining its source. The findings highlight the potential of electron microscopy technology coupled with computer vision and machine learning techniques to enhance our understanding of atmospheric pollution sources, offering valuable insights for PM health risk assessment and evidence-based policy-making.

Effect of Pre-Procedural Antiseptic Mouthwash On The Dentin Bond Strength of Dental Adhesives.

To evaluate the effect of pre-procedural antiseptic mouthwashes on dentin bond strength of different adhesive systems. Flat occlusal dentin surfaces from 120 extracted human molars were randomly divided into four groups according to mouthwashes (0.12% chlorhexidine = CHX, 1% hydrogen peroxide = HP, 0.2% povidone-iodine = PI, and no mouthwash/control) and three subgroups of adhesives used (Clearfil SE Bond; CSE, Single Bond Universal = SBU in etch-and-rinse (ER) or self-etch (SE) modes) (n = 8). Composite resin was built up, and all bonded teeth were stored in 37°C distilled water for 24 h. Stick-shaped specimens were prepared and subjected to microtensile bond strength (µTBS) test. Failure mode analysis was determined using a light microscope. A resin-dentin interface was observed using scanning electron microscopy (SEM, n = 2). Elemental analysis in the PI group was further examined by SEM with energy-dispersive X-ray spectroscopy. The µTBS data were statistically analyzed by two-way analysis of variance (ANOVA) and Duncan's multiple comparison (P < 0.05). Rinsing with PI followed by SBU-SE demonstrated significantly higher µTBS than the control group (P < 0.05). Rinsing with HP showed significantly lower bond strength for CSE (P < 0.05). However, the effect of adhesive systems was not observed for all mouthwashes used (P > 0.05). SEM/EDX revealed the iodine deposition in the underlying dentin, where the highest amount of iodine was found for SBU-SE. CHX and PI can be recommended as pre-procedural antiseptic mouthwashes since they show no negative impact on µTBS for all tested adhesives. The dentin bond strength of CSE is hampered in the HP mouthwash group, and this should be a concern for the use of self-etching adhesive afterward.

Aluminum–Silica Core–Shell Nanoparticles via Nonthermal Plasma Synthesis

Aluminum nanoparticles (Al NPs) are interesting for energetic and plasmonic applications due to their enhanced size-dependent properties. Passivating the surface of these particles is necessary to avoid forming a native oxide layer, which can degrade energetic and optical characteristics. This work utilized a radiofrequency (RF)-driven capacitively coupled argon/hydrogen plasma to form surface-modified Al NPs from aluminum trichloride (AlCl3) vapor and 5% silane in argon (dilute SiH4). Varying the power and dilute SiH4 flow rate in the afterglow of the plasma led to the formation of varying nanoparticle morphologies: Al–SiO2 core–shell, Si–Al2O3 core–shell, and Al–Si Janus particles. Scanning transmission electron microscopy with a high-angle annular dark-field detector (STEM-HAADF) and energy-dispersive X-ray spectroscopy (EDS) were employed for characterization. The surfaces of the nanoparticles and sample composition were characterized and found to be sensitive to changes in RF power input and dilute SiH4 flow rate. This work demonstrates a tunable range of Al–SiO2 core–shell nanoparticles where the Al-to-Si ratio could be varied by changing the plasma parameters. Thermal analysis measurements performed on plasma-synthesized Al, crystalline Si, and Al–SiO2 samples are compared to those from a commercially available 80 nm Al nanopowder. Core–shell particles exhibit an increase in oxidation temperature from 535 °C for Al to 585 °C for Al–SiO2. This all-gas-phase synthesis approach offers a simple preparation method to produce high-purity heterostructured Al NPs.

Synthesis of novel magnesium ferrite Schiff base chitosan nanocomposite for efficient removal of pb(II) ions from aqueous media

In this study, a novel MgFe2O4-Schiff base-chitosan nanocomposite was synthesized using a straightforward crosslinking method. The synthesis involved integrating MgFe2O4 nanoparticles with modified chitosan through a Schiff base formed by the reaction between terephthalaldehyde and aminopyrazine. A comprehensive characterization was performed, including X-ray diffraction analysis, which verified the crystalline structure and the successful incorporation of MgFe2O nanoparticles into the chitosan-Schiff base matrix. Scanning electron microscopy revealed a distinct surface morphology, characterized by a rough, non-uniform alignment resulting from the strong interactions between the nanoparticles and the Schiff base-chitosan matrix. Additionally, energy-dispersive X-ray analysis verified the elemental composition of the nanocomposite, revealing distinct peaks corresponding to carbon, nitrogen, oxygen, magnesium, and iron. The nanocomposite exhibited outstanding performance as a nanoadsorbent for the efficient removal of Pb(II) ions from aqueous media through electrostatic attraction and complexation mechanisms, achieving a maximum adsorption capacity of 290.7 mg g-1. The adsorption process was determined to be spontaneous, endothermic, and chemically driven, aligning well with the Langmuir isotherm model and pseudo-second-order kinetics. The optimal conditions for maximum Pb(II) ions removal were determined to be a pH of 5.5, a contact time of 100 min, and a temperature of 328 K. Furthermore, the nanocomposite demonstrated excellent recyclability, retaining over 94.8% of its initial removal efficiency after five consecutive adsorption-desorption cycles. This study highlights the nanocomposite’s potential as an eco-friendly, cost-effective, and highly efficient material for practical applications in water treatment, addressing the urgent need for sustainable solutions to heavy metal contamination.

Effects of Graphene Nanoplatelets and Nanosized Al4C3 Formation on the Wear Properties of Hot Extruded Al-Based Nanocomposites

This study investigates the influence of graphene nanoplatelets (GNPs) and the formation of nanosized Al4C3 on the tribological performance of hot extruded aluminum-based nanocomposites. Al/GNP nanocomposites with varying GNP contents (0, 0.1, 0.5, and 1.1 wt.%) were fabricated through powder metallurgy, including ball milling, compaction, and hot extrusion at 500 °C, which was designed to facilitate the formation of nanosized carbides during the extrusion process. The effect of GNPs and nanosized carbides on the tribological properties of the composites was evaluated using dry friction pin-on-disk tests to assess wear resistance and the coefficient of friction (COF). Microstructural analyses using scanning electron microscopy and energy-dispersive X-ray spectroscopy confirmed the uniform distribution of GNPs and the formation of nanosized Al4C3 in the samples. Incorporating 0.1 wt.% GNPs resulted in the lowest wear mass loss (1.40 mg) while maintaining a stable COF (0.52), attributed to enhanced lubrication and load transfer. Although a higher GNP content (1.1 wt.%) resulted in increased wear due to agglomeration, the nanocomposite still demonstrated superior wear resistance compared to the unreinforced aluminum matrix. These findings underscore the potential of combining nanotechnology with precise processing techniques to enhance the wear and friction properties of aluminum-based composites.

Study on the processing of thermoplastic polyvinyl alcohol with ammonium salts by melt spinning and its potential as a precursor fiber

Polyvinyl alcohol (PVOH) has all the essential requirements to be used as an alternative precursor for carbon fiber (CF) production. Within this work, three different commercially available, thermoplastically processable PVOH grades together with three different ammonium salts as stabilizing agents were investigated using the melt spinning process with regard to their processing into CF precursor filaments. Precursor filaments could be spun at up to, 500 m min−1. The distribution of the salts over the filament cross-section was evaluated using energy-dispersive X-ray spectroscopy analysis, whereas the quantitative determination was carried out using Kjeldahl nitrogen analysis. The thermal properties were characterized using thermogravimetric analysis. An increase in the ammonium iodine (NH4I) concentration to 10.0 wt.% leads to 22.4 wt.% mass residue at 1000°C. The precursor filaments were carbonized in a laboratory tube furnace up to 1000°C and initial tests were carried out on the resulting CFs.

Mechanical and UV stability of HDPE composites reinforced with carbon black and zinc oxide for solar floater applications

Anti-UV (ultra-violet) hybrid polymer composites were developed for application in floating solar power plants. Virgin high-density polyethylene (HDPE) was mixed with carbon black (CB) in weight percentages of 1.5, 2, and 2.5% with 1, 2, and 3% zinc oxide (ZnO) to prevent the floater from degrading due to UV light. A twin-screw extruder was used to prepare the composite, and four batches were formed. The test sample was prepared by an injection molding machine. After 672, 1413, and 3212 hours of accelerated weathering, the mechanical tests were conducted. After 1413 hours of weathering, pure HDPE loses its tensile strength, impact resistance, and elongation at break. The optimum performance was observed in batch B2, which contains 2% CB and 2% ZnO, with respect to the mechanical properties after UV exposure. The scanning electron microscope (SEM),energy-dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) results also revealed that pure HDPE was more degraded compared to other composites. The strength of the polymer composite will decrease when ZnO and CB concentrations increase further. It was found that HDPE with 2% CB and 2% ZnO is an appropriate composite material for developing floaters used in floating solar power plants.

Novel Ni/SBA-15 Catalyst Pellets for Tar Catalytic Cracking in a Dried Sewage Sludge Pyrolysis Pilot Plant

Novel Ni/SBA-15 catalysts were synthesised and their activity in the dry reforming of methane process was assessed. These materials were prepared into extrudates shaped like pellets and tested in a pyrolysis pilot plant fitted with a catalytic reactor for sewage sludge pyrolysis tar removal. The Ni/SBA-15 catalyst pellets remained highly active and stable throughout the test’s duration, converting 100% tar in the hot gas to smaller non-condensable gases, thereby increasing the pyrolysis gas fraction and eliminating the problematic tar in the vapour stream. Catalyst characterisation with Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray (EDX) analysis, Transmission Electron Microscopy (TEM), and Thermogravimetric Analysis (TGA) confirmed that both the Ni/SBA-15-powered catalyst and the pellets were resistant to sintering and carbon deposition and remained highly active even with relatively high-level sulphur in the feed stream. The Ni/SBA-15 catalyst extrudates were prepared by mixing the powdered catalyst with varied amounts of colloidal silica binder and fixed amounts of methyl cellulose and water. The highest mechanical strength of the extrudates was determined to be of those obtained with 36% of the inorganic binder. The physical properties and catalytic activity of Ni/SBA-15 pellets with 36% colloidal silica were compared with the original powdered Ni/SBA-15 catalyst to assess the binder inhibitory effect, if any. The results confirmed that colloidal silica binder did not inhibit the desired catalyst properties and performance in the reaction. Instead, enhanced catalytic performance was observed.

Revealing Mechanisms of an Eco-Friendly GaN Electrochemical Mechanical Removal Process Modified with Green Fenton Reaction.

Gallium Nitride (GaN), a leading third-generation semiconductor material, offers exceptional properties and broad application potential. However, its high hardness and chemical inertness make GaN wafers difficult to process, posing significant challenges in improving the polishing efficiency. During the electrochemical mechanical polishing (ECMP) process, the oxidation effect on the GaN surface critically affects the material removal rate (MRR). While various methods have been developed to enhance the concentration of hydroxyl radicals (OH*) to improve the process, their instability and rapid decomposition present further obstacles to maintaining concentration and stability. The present study proposed a novel approach using sodium tripolyphosphate (STPP) as an electrolyte additive for ECMP under a green Fenton reaction. Furthermore, the MRR and surface roughness (Ra) of GaN-ECMP were comprehensively evaluated. Atomic force microscopy (AFM) was used to observe the surface morphologies of GaN wafers after ECMP. Energy-dispersive spectrometry (EDS) and X-ray Photoelectron Spectroscopy (XPS) were used to characterize the generated oxide layers. The nanoscratch tests were conducted to reveal the material removal mechanisms of GaN under the synergistic effect of STPP and Fe2+. The results indicated that an efficient GaN-ECMP process (MRR > 800 nm/h) with good surface quality (Ra < 0.33 nm) can be realized by employing STPP as electrolyte additives. This study breaks the limitation of iron precipitate formation in the ECMP slurries during the Fenton reaction. It extends the lifetime of the hydroxyl radicals (OH*) produced by the Fenton reaction, which presents a beneficial exploration of seeking an eco-friendly polishing slurry for GaN-ECMP.

Microanalysis of minerals in Rhizophora mangle L. leaves from Marambaia mangroves reveal low presence of potentially toxic elements

The mangroves of Marambaia, area bathed by the Bay of Sepetiba, is located in an area protected by the Brazilian Army and has a remarkable level of environmental protection among ecosystems around the bay. Leaf content of minerals and potentially toxic elements in a typical species of mangrove of Rhizophora mangle L. were analyzed from samples collected in Marambaia. Microanalyses of minerals were done by Energy Dispersive X-Ray Spectroscopy coupled to Scanning Electron Microscope (EDX-SEM) that showed the elemental composition and its relative quantity in R. mangle leaves. The major mineral deteced were Na, Ca and Cl, and low concentration of Zn.

Utilization of a Selective Paper-Based Flexible Electrochemical Sensor for Epinephrine Determination in Artificial Sweat Using Nickel Oxide and Sulfur-Doped Graphene Conductive Ink

Abstract Epinephrine (adrenaline, EP) is a crucial hormone that regulates the body's response to emergencies. During periods of stress or danger, it is responsible for rapidly mobilizing the body by elevating heart rate, blood pressure, and respiratory rate. Consequently, the accurate and rapid measurement of EP is of significant importance. In this study, sulfur-doped graphene (S-Gr) synthesized using Yucel’s method, and nickel oxide (NiO) were utilized as conductive materials to develop conductive inks. Furthermore, a paper-based flexible electrochemical sensor was constructed for EP determination. The optimum conductive ink for sensor fabrication was identified through optimization process. The sensor was characterized using various techniques, including cyclic voltammetry, electrochemical impedance spectroscopy, field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction analysis, and Fourier transform infrared spectroscopy. The sensor demonstrated a detection limit of 33.16 nM, and its cost-effective and user-friendly design renders it an advantageous option for practical applications. The results obtained from the analytical studies indicated that the sensor exhibits high selectivity towards EP and can successfully detect EP in artificial sweat samples. In conclusion, the proposed sensor serves as a model for future flexible and wearable devices.

Radiation-assisted synthesis of hydroxyethyl cellulose and acrylic acid hydrogel modified with novel surfactants for Pb (II) removal

ABSTRACT In this study, hydrogels crosslinked with varying weight ratios of hydroxy ethyl cellulose and acrylic acid were synthesised via gamma rays with a 30 KGy. These polymers were further modified with two surfactants: a cationic surfactant, 1-hexadecyl-2-vinyl pyridinium chloride and an amphoteric surfactant, sodium salt of 2-(1-hexadecylpyridinium chloride-2-yl) ethane-1-sulphonate. The chemical structures of these surfactants were elucidated spectroscopically, while their morphologies and elemental analysis were examined by Scanning Electron Microscope (SEM) and energy-dispersive X-ray (EDX), respectively. Batch adsorption parameters revealed that each improved hydrogel was effective in adsorbing Pb2+ ions. The best conditions of adsorption were achieved within 240 min at pH = 5 and v/m = 0.4 L/g. The selectivity of lead removal based on synthesised solutions (Pb, Zn and Co) using hydrogel materials was analysed for their potential application in environmental remediation efforts. The adsorption of lead (II) ions onto synthesised polymers was studied using kinetic modelling and adsorption isotherms. Results fit the Freundlich isotherm and pseudo-first-order kinetic model. Thermodynamic parameters, with enthalpy (ΔH) values of 28.50 to 43.46 kJ/mol and Gibbs free energy (ΔG) values from −2.58 to −7.28 kJ/mol at 338 K, show the process is endothermic and spontaneous. The positive entropy (ΔS) values indicate increased disorder at the interface.