SEM-EDX Analysis Research Articles

Enhanced performance of UiO-66 for supercapacitor applications through oxidation via the Hummers' method.

Supercapacitors (SCs) are gaining attention in energy storage due to their high-power density, rapid charge/discharge ability, and long life cycle. Improving these features relies on developing advanced electrode materials with better energy storage properties. This study explores UiO-66, a zirconium-based metal-organic framework (MOF), which offers advantages like a large surface area, tunable pore sizes, and stability. However, its poor electrical conductivity limits its use in supercapacitors. Herein, we applied the Hummers' method to oxidize UiO-66, creating an oxidized form, H-UiO-66, with enhanced conductivity. This material was characterized by various techniques, including SEM-EDX, XRD, XPS, FTIR, and BET analysis, while electrochemical tests (GCD, CV, and EIS) confirmed a significant improvement in specific capacitance-82.8 F g-1 for H-UiO-66 versus 0.18 F g-1 for pristine UiO-66 at 1 mA. These improvements stem from increased conductivity and electrochemical activity due to UiO-66 graphitization, highlighting the Hummers' method's effectiveness in transforming UiO-66 into a viable supercapacitor material.

Effect of mechanical instrumentation on titanium implant surface properties.

To assess the impact of mechanical decontamination using rotary brushes on the surface topography, elemental composition, roughness, and wettability of titanium implant surfaces. Four commercially available rotary brushes were used: Labrida BioClean Brush® (LB), i-Brush1 (IB), NiTiBrush Nano (NiTiB), and Peri-implantitis Brush (PIB). Seventy-five titanium discs with sandblasted, large-grit, acid-etched (SLA) surfaces were randomly assigned to five groups (n = 15): LB, IB, NiTiB, PIB, and a control group. Each disc was treated for 60 seconds with the respective rotary brush according to the manufacturer's instructions. Surface morphology was analysed using Scanning Electron Microscopy (SEM), surface elemental composition with Energy Dispersive X-ray (EDX), surface roughness via optical profilometry, and wettability with a droplet shape analyser. SEI analysis revealed morphological changes, including scratches, flattening, and loose titanium particles in the IB, PIB, and NiTiB groups, whereas the LB group preserved the original surface morphology. SEM-EDX analysis showed that LB, PIB, and NiTiB groups closely match the control elemental composition. However, IB groups showed significantly different composition. Surface roughness values in the IB, PIB, and NiTiB groups differed significantly from the control (p < 0.05), whereas the LB group had comparable roughness values (p > 0.05). Contact angle measurements indicated enhanced wettability in IB, PIB, and NiTiB groups (p < 0.05), while the LB group exhibited values comparable to the control (p > 0.05). Mechanical decontamination of implant surfaces utilising rotary brushes can alter implant surface properties.

Study of Crystal Structure, Lattice Strain, and Elemental Content of Natural Iron Sand Nanoparticles Synthesized by the Coprecipitation Method

This study was conducted to investigate the synthesis of magnetite nanoparticles from iron sand collected from the Bah Bolon River in Indonesia, using the coprecipitation method with NaOH and NH4OH as precipitants. The results showed that based on SEM-EDX (scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy) analysis, the Fe content of the raw iron sand, initially at 34.76%, increased to 45.50% following synthesis with NH4OH, indicating enhanced purity in the final product. SEM observations found average particle sizes of approximately 53 nm for nanoparticles synthesized with NaOH and 20 nm for those synthesized with NH4OH. X-ray diffraction (XRD) analysis confirmed that the synthesized nanoparticles retain the magnetite (Fe3O4) phase with a face-centered cubic (FCC) spinel structure. Crystallite size calculations using the Scherrer equation yielded average crystallite sizes of 80.194 nm for NaOH-synthesized samples and 15.124 nm for NH4OH-synthesized samples, demonstrating that NH4OH favors the formation of smaller crystallites. Lattice strain analysis through the Williamson-Hall method showed positive tensile strain values for all samples, indicating structural tension within the crystal lattice. The NH4OH-synthesized nanoparticles had slightly higher lattice strain, suggesting that synthesis conditions impact both crystallite size and lattice tension. In conclusion, this study demonstrated that NH4OH was more effective than NaOH in producing high-purity, small-crystallite magnetite nanoparticles from natural iron sand, with potential implications for enhanced material properties.

Biomimetic Effect of Saliva on Human Tooth Enamel: A Scanning Electron Microscopic Study.

Introduction: Due to the presence of ion reservoir, saliva may facilitate enamel remineralization and neutralize pH of acidic beverage leads to prevent enamel demineralization. Saliva substitute/artificial saliva has been developed in subsequent years and may differ in physical properties, function, or pH level from 5.0 to 7.3. Objectives: To evaluate the biomimetic effect of saliva (neutralization) on tooth enamel exposed to carbonated beverage (pH 2.44) and to observe therapeutic capability (remineralization) of artificial saliva over previously eroded (grade 3 and grade 5) enamel surface. Methods: After scanning with electron microscope (SEM-EDX), nondemineralized crown samples (n = 40) were randomly grouped into two. Samples (50%) were flushed all around to carbonated beverage with collected natural saliva bathing simultaneously (experimental group, n = 20), and the rest flushed to beverage only without saliva bathing simultaneously (control group, n = 20). Flushing action was performed for 3 min by a customized digital automatic flusher for 30 times for each sample. Samples (n = 40) were further scanned under SEM-EDX to evaluate the demineralization grade and concentration of Ca, P, O, and C elements of crown samples to find out the neutralization effect of saliva. In the second phase, already demineralized crown samples (n = 30) were randomly treated with artificial saliva having two different pH (7 or 6.8, experimental groups) and distilled water (control group) for 15 min 3 times daily for 30 days. The remineralization score of experimental samples was graded, and therapeutic capability was established. Results: Samples, when exposed to a carbonated beverage with saliva bathing simultaneously, showed low level of demineralization (mean 2.9 ± 0.3) than the control (without saliva) (mean 4.8 ± 0.3) (p = 0.01) which indicated neutralization (bioimimetic) effect of natural saliva. All (100%) of demineralized samples treated with both artificial saliva (pH 7 or pH 6.8) showed significant remineralization (p = 0.01), thus revealed biomimetic capacity. SEM-EDX analysis showed initial (before beverage exposure) concentrations of calcium, phosphorus, oxygen, and carbon elements of crown samples were 32.48%, 31.5%, 28.3%, and 5.5%, respectively. The calcium (Ca) (9.7%) and phosphorous (P) (18.5%) values were more decreased after beverage exposure without saliva bathing simultaneously compared to after beverage exposure with saliva bathing simultaneously. The concentration of oxygen (54.4%) and carbon (15.5%) were more increased after beverage exposure without saliva bathing simultaneously compared to after beverage exposure with saliva bathing simultaneously. Though the concentration of calcium (38.5%) of the crown sample was increased after treatment with artificial saliva (pH 7), but the phosphorus (18.5%) concentration of the crown sample was not increased. Conclusion: Within the context of the present study, both natural and artificial saliva showed significant biomimetic effects with respect to neutralization and remineralization.

Temperature and Cr-Co ratio on Production of Diethyl Ether from Ethanol Dehydration using Cr-Co/γ-Al2O3 Catalyst

The running down of fossil fuels and rising environmental concerns, there is an increasing emphasis on identifying eco-friendly alternative energy sources. Diethyl ether (DEE) is considered one such additive fuel that can replace fossil fuels. In this study, DEE was synthesized through the reaction dehydration of ethanol using γ-alumina catalysts impregnated with chromium and cobalt. The dehydration of ethanol performed in a fixed bed reactor using Cr-Co/γ-Al2O3catalysts loading. The effect of metal ratio of Cr-Co was examined. Catalyst characterization was carried out using XRD, BET, and SEM-EDX analyses. The dehydration reaction was conducted in a fixed-bed reactor at temperatures 100 to 200 ºC, with nitrogen gas flowrates between 200 and 600 mL/min as the carrier gas. The findings revealed that the increase chromium contents, and the temperature were augmenting the diethyl ether yield. And the increase of nitrogen flow rate is slightly increasing the yield of DEE and conversion of ethanol. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Chitosan/TiO2/Rosmarinic Acid Bio-Nanocomposite Coatings: Characterization and Preparation

This study aimed to develop and characterize bio-nanocomposite coatings by incorporating titanium nanoparticles (TiO2 NPs) (30–50 nm) (10 mg/L), which have antimicrobial effects, and rosmarinic acid (RA) (0.005 mg/mL), which has strong antioxidant and antimicrobial activities, into the chitosan matrix using the solvent casting method. The prepared bio-nanocomposite coatings were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM-EDX), and atomic force microscopy (AFM). In the XRD analysis, the crystal structure of the bio-nanocomposite coating material was evaluated, but the absence of the expected TiO2 NPs diffraction peak in the coating containing TiO2 NPs was discussed in detail. The TiO2 NPs decreased the crystallinity, compared to the control film, while rosmarinic acid increased the order of the molecular matrix. FT-IR analysis showed the presences of O–H, C=O, and C–O bonds in the coating materials, and the changes in the positions and intensities of the bands observed in the FTIR spectra of the bio-nanocomposite coatings (CHT and CHTRA) proved that TiO2 NPs and RA were successfully integrated into the chitosan matrix. The broadening and flattening of the bands belonging to OH groups (3288–3356 cm−1) indicated that the hydrogen bonds in the chitosan matrix were strengthened during the formation of the bio-nanocomposite structure. The bands representing the C=O stretching vibrations at 1659 cm−1 (amide I) and the N–H bending vibrations at 1558 cm−1 (amide II) indicated protein-based features in the structure of chitosan and confirmed the existence of the bio-nanocomposite structure. The SEM-EDX analysis showed that TiO2 NPs were distributed homogeneously on the chitosan surface, but there was aggregation in places. The AFM images revealed that when TiO2 NPs and RA were added to the chitosan matrix, the surface topography became more homogeneous, and a topographic pattern was formed in the range of 0–20.4 nm. Therefore, it is concluded that these bio-nanocomposite coatings can be used in antimicrobial surfaces and food packaging areas and should be optimized with different antioxidant and nanoparticle combinations in the future.

Biosynthesis of novel MnO&lt;SUB&gt;2&lt;/SUB&gt; nanocapsules via &lt;I&gt;C. spinosa&lt;/I&gt; extract and honeybee-derived chitosan: exploring antibacterial and anticancer properties

This investigation delves into the integration of Capparis spinosa extract (CSLe) onto manganese dioxide nanoparticles (MnO2NPs) and chitosan derived from honeybees (CSH) in a nanostructured configuration. The resultant nanocomposites, namely CSLe@MnO2NPs and CSH/CSLe@MnO2NPs, underwent thorough characterization through various analytical techniques. UV-Vis spectroscopy unveiled distinctive features, such as ligand-to-metal charge transfer and photoluminescence, affirming the successful chitosan-functionalization of the MnO2NPs, thereby differentiating them from their pristine counterparts. FTIR spectra corroborated the binding of chitosan and identified crucial molecular functional groups. SEM-EDX analysis revealed the morphological properties, addressing non-uniform sizes in the as-calcined MnO2NPs by the uniform coating of CSH on CSLe@MnO2NPs, while EDX confirmed the presence of essential elements. TEM and SAED provided insights into the spherical morphology, crystalline structure, and lattice planes of these nanoparticles. Size distribution measurements highlighted distinctions between CSLe@MnO2NPs and CSH/CSLe@MnO2NPs. The nanomaterials underwent evaluation for their antimicrobial properties against a spectrum of Gram-negative and Gram-positive bacterial strains, with CSH/CSLe@MnO2NPs exhibiting the highest bactericidal activity. Additionally, they demonstrated low minimum inhibitory concentration (MIC) values, especially against S. aureus (MIC as low as 12.5 µg/ml). Their efficacy extended to anti-biofilm formation, significantly diminishing biofilm development in a dose-dependent manner, a pivotal factor in addressing biofilm-related infections. The study also scrutinized their cytotoxicity against normal Vero and PC3 prostate cancer cells, revealing potential anticancer properties. Dose-dependent reductions in cell viability were observed for both normal and cancer cells. In conclusion, these findings underscore the versatility and promise of CSH/CSLe@MnO2NPs in diverse biomedical applications, including antibacterial, anti-biofilm, and anticancer therapies.

Comparison of Sulfamethoxazole Removal Efficiency Using Polyethersulfone Ultrafiltration Membrane Modified by Various Methods.

Nowadays, there is a growing interest in membrane modification processes to improve their characteristics and the effectiveness of their treatments and reduce the possible fouling. In this sense, in this work, a modification of an ultrafiltration membrane with three different materials has been carried out: reduced graphene oxide (rGO), chitosan and MgCl2. For both the native and the modified membranes, a study has been carried out to remove the emerging contaminant sulfamethoxazole (SMX). SEM and SEM-EDX analyses have been performed to confirm membrane surface modifications. In the characterisation of the membranes, it is noteworthy that the values of the permeability coefficient, Aw, have been lower in the modified membranes, which is unexpected. Regarding the pollutant removal tests, the influence of pressure and initial concentration on permeate flux and rejections has been studied. Native membrane shows the highest permeate flux values. Comparing the modified membranes, the highest rejection values are obtained with the rGO-modified membrane, which can be explained by its greater hydrophilic character. Finally, a fouling study was carried out, verifying that in almost all cases, fouling occurs after the passage of the pollutant due to the blockage of the membrane pores.

Fabrication and Characterization of Amphotericin B Loaded Poly(Vinyl Alcohol)/Chitosan‐ZnO Biocomposite Films for Antimicrobial Wound Dressings

ABSTRACTDeveloping efficient hydrogel‐based wound dressings has gained increasing attention in improved wound healing capabilities. In this study, the biocomposite hydrogel films consisting of polyvinyl alcohol (PVA), chitosan (CS), and zinc oxide nanoparticles (ZnO NPs) were prepared using the solvent casting method. The biocomposite hydrogel films were also loaded (5% w/w) with Amphotericin B (AmB) as a model drug to develop a new suitable material with potential application as high‐performance wound dressing with controlled drug release. The chemical nature, thermal properties, and morphology of the PVA/CS and PVA/CS‐ZnO biocomposite hydrogels were analyzed and compared by FTIR, TGA, and SEM–EDX analysis. The effect of ZnO NPs on swelling behavior in the PVA/CS films was studied. PVA/CS‐ZnO biocomposite hydrogels presented a lesser degree of swelling compared to ZnO‐free hydrogels. The AmB‐loaded hydrogel films exhibited a sustained release rate during 72 h in PBS at pH 7.4. Biocompatibility of all hydrogel types (with or without ZnO and AmB) using L929 and HaCaT cell lines was evaluated with high cell viability examined by MTT assay. The antimicrobial activity of the films was evaluated against Escherichia coli, Staphylococcus aureus, and Candida albicans using a modified AATCC 100 method, whereby the R value represents the log reduction in the number of surviving colonies. The mean R values for drug‐free PVA/CS‐ZnO hydrogel films were 6.81 for E. coli, 6.03 for S. aureus, and 6.82 for C. albicans. The addition of AmB further enhanced the antimicrobial activity, increasing the R values for E. coli to 7.16, for S. aureus to 6.38, and for C. albicans to 7.31, demonstrating a significant synergistic effect with maximum antimicrobial efficacy. The results showed that the AmB‐loaded biocomposite hydrogel films (PVA/CS‐ZnO‐AmB) can be used as a new wound dressing material.

Synthesis and Characterization of Binary Azides (e.g. RbN3) via Ion-Exchange Method

Azides have garnered significant interest in chemical research for their diverse properties and applications, ranging from their use in airbags and detonators to their roles in photochemistry. Despite this attention, there remains a dearth of detailed studies focusing on the synthesis and characterization of binary azides. In this study, a robust and safe method for the synthesis of RbN3 via ion exchange is presented, addressing the inherent challenges associated with handling highly explosive alkali metal azides. The experimental procedure, conducted under stringent safety measures, resulted in the successful production of high-purity RbN3, as confirmed by X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy analyses. XRPD data with the reference intensity ratio method (RIR) confirmed phase purity above 99 %, which is in good agreement with the elemental ratio found by SEM-EDX analysis. The synthesized RbN3 exhibited crystalline white powder morphology, free from impurities, thus demonstrating the efficacy of the ion exchange approach. X-ray powder diffraction (XRPD) and Vibrational spectroscopy analyses provided additional insights into the structure and purity of RbN3 in accordance with theoretical expectations; the characteristic vibrational modes for N3- could be well found at the expected theoretical and experimental ranges. These findings show an easy, safe, and reliable method for synthesizing binary azides and contribute to a deeper understanding of azide chemistry, with implications for various scientific disciplines.

Green electrochemical sensor for selective determination of anticancer drug Ribociclib based on banana peel activated carbon/CuCoFe-MOF/CoFe2O4 modified carbon paste electrode in pharmaceutical and biological samples

The development of efficient and eco-friendly sensing platforms for the sensitive detection of anticancer drugs like Ribociclib (RIB) is essential for advancing therapeutic monitoring and ensuring patient safety. In this study, we introduce a novel electrochemical sensor that utilizes a unique CuCoFe-MOF/CoFe2O4/banana peel activated carbon (BPAC) composite-modified carbon paste electrode (CPE) for the sensitive quantification of RIB. This composite material, which has not been previously reported in the literature, offers enhanced electrocatalytic activity, attributed to its increased surface area and superior conductivity. Various techniques, including FT-IR, XRD, SEM-EDX, and BET analysis, were used to confirm the structural and morphological properties of the synthesized composite. Differential pulse voltammetry (DPV) results showed a broad linear range of 0.2–9.7 μM and a remarkably low limit of detection (LOD) of 0.025 μM, demonstrating its high sensitivity. The sensor’s performance was further validated in pharmaceutical formulations and biological samples, achieving recoveries between 98.6 % and 101.8 % with an RSD below 2.0 %. Additionally, the method was evaluated using the Green Analytical Procedure Index (GAPI), Analytical Greenness (AGREE), and Blue Applicability Grade Index (BAGI) tools, confirming that it is both green and highly applicable. This work presents a significant advancement in the field of electrochemical sensing for RIB detection, offering a novel, sustainable, and practical solution for real-world applications.

Effect of Fosroc Cebex-100 and Fly Ash Stabilization on the Microstructural Properties of Soft Soil

This study investigates the microstructural effects of stabilizing soft soil using fly ash and Fosroc Cebex-100. The soft soil used in this study was collected from the construction site of the Northern Ring Road (JLU) Section 1 in Lamongan regency. Firstly, a series of laboratory soil test was performed to obtain the index properties of the soil sample including unit weight, specific gravity, Atterberg’s limits, optimum moisture content, and maximum dry unit weight. The soil was then treated with three variations of fly ash (20%, 25%, and 30%), while the Fosroc Cebex-100 dosage was held constant at 0.45% of the fly ash weight. A CBR test indicated that a 20% fly ash and Fosroc Cebex-100 mixture achieved the highest CBR value. Consequently, this optimal mix was selected for SEM-EDX (Scanning Electron Microscopy - Energy-Dispersive X-ray Spectroscopy) analysis to further examine microstructural characteristics. Additional fly ash and Fosroc Cebex-100 to the soft soil will influence the microstructural properties of the soil. SEM analysis show that addition of fly ash and Fosroc Cebex-100 results in significant changes in the soil matrix, including increased particle bonding, reduced porosity, and a denser overall structure. Moreover, the addition of fly ash and Fosroc Cebex-100 contribute to the presence of iron (Fe) in the treated soil.

Modification &amp; Characterization of Activated Carbon Impregnated with KCl, Na2S, and KI for Enhancing Mercury (Hg) Removal from Natural Gas

Modified activated carbon (MAC) has been synthesized and characterized to enhance mercury (Hg) removal from natural gas. MAC was modified by impregnating it into KCl, Na2S, and KI to introduce Cl-, S-, and I- elements. SEM-EDX, FTIR, and SAA were used to characterize the AC and MAC. The isotherm and adsorption capacity were studied using the mercury gas standard. The results of SEM-EDX analysis show that the impregnation method is proven to produce MAC containing elements Cl, S, and I with mass % of 2.78% Cl, 0.76% S, and 39.60% I. The surface area is 421.91 m2/g, the total pore volume is 0.386825 cc/g, and the average pore size is 1.83369 nm. Group functions are -OH, C=C, C=O, C-O, and vibrations at the wavelength number 617.81 cm-1, which the impregnation agent forms. The mechanism for absorbing mercury gas into MAC follows the Freundlich isotherm model, with a coefficient of determination (R2) of 0.996. The adsorption capacity on MAC increased 57 times compared to unmodified activated carbon (AC) from 5540.60 to 315730.64 ng/g, with an efficiency maximum of 100%. The MAC has been proven to enhance mercury adsorption from natural gas with an efficiency of 78.6%.

Synthesis of a Novel Magnetic Biochar from Lemon Peels via Impregnation-Pyrolysis for the Removal of Methyl Orange from Wastewater

This research examined the elimination of methyl orange (MO) utilizing a novel magnetic biochar adsorbent (MLPB) derived from lemon peels via an impregnation-pyrolysis method. Material characterization was conducted using SEM, XRD, TGA, FTIR, and nitrogen adsorption isotherms. SEM-EDX analysis indicates that MLPB is a homogeneous and porous composite comprising Fe, O, and C, with iron oxide uniformly dispersed throughout the material. Also, MLPB is porous with an average pore diameter of 4.65 nm and surface area value (111.45 m2/g). This study evaluated pH, MO concentration, and contact time to analyze the adsorption process, kinetics, and isothermal behavior. Under optimal conditions, MLPB was able to remove MO dye from aqueous solutions with an efficiency of 90.87%. Results showed optimal MO removal at pH 4, suggesting a favorable electrostatic interaction between the adsorbent and dye. To ascertain the adsorption kinetics, the experimental findings were compared using several adsorption models, first- and second-orders, and intra-particle diffusion. According to the findings, the pseudo-second-order model described the adsorption kinetic promoting the formation of the chemisorption phase well. Modeling of intra-particle diffusion revealed that intra-particle diffusion is not the only rate-limiting step. A study involving isothermal systems showed that Langmuir is a good representation of experimental results; the maximum adsorption capacity of MLPB was 17.21 mg/g. According to the results, after four cycles of regeneration, the produced magnetic material regained more than 88% of its adsorption ability.

Lead removal by its precipitation with biogenic sulfide in a membrane biofilm reactor

We evaluated the feasibility of using hydrogen (H2)-based membrane biofilm reactors (MBfRs) to promote the growth of hydrogenotrophic sulfate-reducing bacteria (SRB) to remove lead (Pb) through its precipitation as lead sulfide (PbS) via biogenic sulfide (HS−) production. Two MBfRs (R1 and R2) were set-up to treat synthetic water rich in sulfate (SO42−) (585 mg/L) and Pb (50, 100, or 250 mg/L). R1 had one influent that had the Pb and synthetic media mixed together; R2 received the Pb solution and synthetic medium through separate influent lines. Oxygen (O2) and nitrate (NO3−) were secondary electron acceptors in R1 and R2, respectively. R1 and R2 produced enough HS− (> 73 mg/L) to precipitate Pb, and Pb removal reached >97 %. Chemical equilibrium calculations identified which solids were possible in each stage of operation. Precipitation of Pb with phosphate (PO43−) occurred in the feed solution in R1, but phosphate precipitation was avoided in the R2 influent. The predominant Pb precipitate inside R2 was PbS, which was confirmed by SEM-EDX analysis. The microbial communities of R1 and R2 were dominated by two SRB – Desulfomicrobium and Fusibacter – along with sulfur oxidizer Thiovirga and denitrifier Thauera. Although the presence of electron acceptors other than SO42− enabled other respiratory metabolisms, they did not prevent SO42− reduction to HS− or the precipitation of PbS.

Regenerable nickel catalysts strengthened against H2S poisoning in dry reforming of methane

In this study, alumina-supported bimetallic Ni-Cu and trimetallic Ni-Cu-Ce catalysts were synthesized to improve catalysts resistant to coke formation and sulfur poisoning for dry reforming of methane (DRM). The effects of parameters such as feed composition, synthesis method, and H2S concentration using the catalyst with the best activity were also investigated. To determine the physical and chemical properties of the synthesized catalysts, XRD, N2 adsorption–desorption, TGA-DTA, ICP-OES, SEM-EDX, XPS, and DRIFTS analyses were performed. XRD analysis showed that the fresh Ni-Cu catalysts have elemental nickel and γ-alumina phases in their structures. In addition to these structures, the CeO2 crystal structure was determined for the Ni-Cu-Ce catalyst. Type IV isotherm with H1 hysteresis indicating uniform mesoporous structure was obtained with all the catalysts. The activities of the synthesized catalysts in DRM were performed in the presence of different concentrations of H2S (2 ppm, 50 ppm, and 500 ppm) in a fixed bed reactor at 750 °C using a gas chromatography-equipped system. The alumina-supported 8Ni-3Cu-8Ce catalyst prepared by the impregnation method exhibited a higher and more stable activity comparing the bimetallic Ni-Cu catalyst in the presence of H2S. Adding copper and cerium to the nickel catalyst has a curative effect on resistance to coke formation and sulfur poisoning. Excess CO2 in the feed stream increased the H2S poisoning resistance of the catalyst. To analyze the reactor exit stream in catalytic activity using different feed stream compositions such as H2S+He, H2S+CO2+He, and H2S+CO2+CH4+He, FTIR with a gas cell was used. The formation of carbonyl sulfide (COS) and H2O, which occurs due to the possible reaction between CO2 and H2S, was observed. Regeneration studies showed that the catalyst could undergo regeneration with a low oxygen concentration (0.3 % O2 in He). 8Ni-3Cu-8Ce@SGA, which gave 71 % CH4 conversion in the first minute of the reaction test in the presence of 50 ppm H2S, was regenerated after completely losing its activity at the end of 5 h. 66 % CH4 conversion was achieved when tested again in the absence of H2S (CH4/CO2/Ar:1/1/1). The 8Ni-3Cu-8Ce@SGA catalyst was deemed worthy of investigation for industrial applications.

Comprehensive spectroscopic and morphological analysis of the effects exerted by different acids on Pig bone: Forensic aspect

Demineralization of the chemically treated pig shoulder bone in hydrochloric, hydrofluoric, and acetic acid was monitored by ATR-FTIR, Raman, and LIBS spectroscopies and SEM-EDX technique. SEM-EDX analysis showed reduced calcium and phosphorus content after the treatment with acids and erosion of the overall morphology of the bone compared to the sample kept in water. Alterations in bone structure during the 14-day-long immersion in acid solutions indicated significant chemical changes in the obtained spectra. Fourier deconvolution applied in the amide I (1700–1600 cm−1), phosphate (900–1200 cm−1), and carbonate (500–650 cm−1) region indicated the presence of different components in the bone sample, depending on the environment and acid concentration, providing information about the composition. Parameters such as mineral-to-matrix ratio, crystallinity index, and carbonate-to-phosphate ratio were calculated and compared using ATR-FTIR and Raman data. These parameters were also correlated with calcium ionic-to-atomic and phosphorous-to-carbon line intensities obtained from LIBS spectra. Calcium and phosphorus atomic contents obtained by SEM-EDX analysis were in agreement with LIBS data. The results suggested that an increase in acid concentration has primarily affected the phosphate band’s intensity and structure, as the phosphate content was more susceptible to demineralization. Hydrochloric acid was proven to be a more powerful demineralization agent than hydrofluoric and acetic acids. The results of this study could be further applied to the investigation of the bone remains at the crime scene, especially when their removal is attempted by immersion in acid solutions.

Chankanai Zeolite Modified with Heteroatomic Derivatives of 3-Aminopropyltriethoxysilane as an Effective Sorbent for Ag(I), Co(II)

Bis-N,N-(3-triethoxysilylpropyl)thiosemicarbazide 3 was obtained by the condensation of 3-aminopropyltriethoxysilane 1 with thiosemicarbazide 2. Ethyl ether N-[3-(triethoxysilyl)propyl]-b-alanine 5 was obtained by the interaction of an equimolar amount of aminopropyltriethoxysilane 1 and ethyl acrylate 4 (aza-Michael reaction). Synthesized functional organosilanes 3 and 5 were successfully immobilized on the surface of natural zeolite Z (Chankanai deposit, Kazakhstan). Compounds and materials have been studied by NMR and IR Fourier spectroscopy and X-ray diffraction analysis. The elemental composition and morphology of modified zeolites Z3 and Z5 were studied using SEM-EDX analysis. The modification of zeolite by organosilanes 3 and 5 leads to changes in the surface structure of the material: with the enlargement of particles and agglomerates, the surface becomes more homogeneous and less porous. This indicates a high degree of zeolite coverage by the modifier layer. The study of the sorption characteristics of the initial Z and modified zeolites (Z3 and Z5) showed a high sorption capacity relative to Ag(I) and Co(II) (static sorption capacity, SSC = 35.85–23.92 mg/g), whereas the SSC values for Z were SSC = 20.63 and 16.64 mg/g. The adsorption of Ag(I) and Co(II) ions was studied in solutions prepared using Co(NO3)2·6H2O, AgNO3 and distilled water. The choice of the initial concentration of metal ions, as well as the pH of the solutions, corresponded to the composition of wastewater from real electroplating production. Zeolites Z3 and Z5 can be used in various sectors of industry, in ecology and for medical purposes as inexpensive and effective adsorbents (enterosorbents) of heavy and noble metals.

Green synthesis of template-free NiFe2O4 nanoparticles: A promising sustainable catalyst for efficient benzaldehyde and phenolic motifs development

This study introduces cost-effective and eco-friendly approach utilizing Camellia sinensis var. Assamica leaves for biogenic synthesis of NiFe2O4 magnetic nanoparticles. The synthesized nanoparticles underwent comprehensive characterization employing SEM-EDX, VSM, PXRD, XPS and TEM analyses to provide detailed insights into their properties. TEM investigations unveiled the formation of spherical NiFe2O4 magnetic nanoparticles, while VSM analysis revealed their ferromagnetic behavior. They demonstrate outstanding catalytic performance in the ipso-hydroxylation of arylboronic acids within very short amount of time without using any solvent/ base at room temperature. Remarkably, under base-free and mild reaction conditions, a diverse range of benzyl alcohols exhibited conversion to their corresponding aldehydes, showcasing the versatility and efficacy of as-synthesized nanoparticles. These nanoparticles could be readily separated using magnet and maintain their catalytic activity consistently for upto fifth run in both reactions, presenting significant economic advantages for potential industrial applications.

Fe-N-C Catalysts Surpassing Pt Catalysts in ORR for Fuel Cells

As countries ramp up efforts towards achieving carbon neutrality, fuel cells are garnering attention. Conventional fuel cells, utilizing precious metals like Pt, face challenges due to resource and cost constraints. Addressing this issue is seen as a key step towards further proliferation of fuel cells. Therefore, we are conducting research on Fe-N-C catalysts, which utilize abundant and affordable metals like iron, aiming to overcome these challenges. Cathode-side oxygen reduction reaction (ORR) occurring at a higher potential and smooth 4-electron reduction are key factors leading to the improvement of fuel cell performance. In this study, we synthesized Fe-N-C catalysts with modifications made by us to enable synthesis in university labs, based on the method reported by Prof. Plamen Atanassov (standard catalyst)1. Subsequently, we aimed for further performance enhancement by improving the catalyst synthesis process.We mixed the materials for the catalyst (water, glucose, 2-methylimidazole, zinc nitrate hexahydrate, iron (Ⅲ) nitrate nonahydrate), and conducted a 24-hour hydrothermal synthesis at 200 ℃. Afterwards, we conducted heat treatment in an H2 gas atmosphere, followed by acid washing using nitric acid to remove residual metallic iron in the solution. Subsequently, the catalyst was synthesized through heat treatment in an NH3 gas atmosphere. Furthermore, we prepared the catalyst, ionomer (Nafion), and solvent to create catalyst ink, and conducted cyclic voltammetry (CV) measurements using a rotating ring-disk electrode. Firstly, preventing to generate the metallic iron particles that interferes with the catalytic reaction, we reduced the amount of iron nitrate nonahydrate used and extended the acid washing time. Furthermore, we extended the heat treatment time and changed the gas from H2 to NH3. Additionally, for improved catalyst, according to minimizing the iron source, we also reduced the amount of ionomer to achieve an ideal triple phase boundary (TPB).In cyclic voltammetry, the improved catalyst started the reduction reaction at a potential 0.02 V higher than the platinum catalyst and 0.1 V higher than the standard catalyst. (Fig.1) The Fe-N coordination structure of the improved catalyst was stabilized by changing the heat treatment conditions. In addition, the development in the crystallinity of the carbon is considered to have improved the conductivity. We speculated that an excess of ionomer leads to prevent oxygen from the gas phase against reaching the active sites. Therefore, the optimal ratio of the amount of iron source to the amount of ionomer was considered to be responsible for the oxygen reduction reaction with low overpotential. Next, we analyze the crystal structures of both improved and standard catalysts using XRD (between 10° and 100° 2θ using Cu target). Residual FCC-Fe was observed on the standard catalyst (2θ : 43°, 52°, 74°), while no iron metal or iron oxide particles were observed on the improved catalyst1. (Fig.2) Furthermore, SEM-EDX analysis showed a reduction in residual metallic iron. This suggests that the improved catalyst succeeded in significantly removing metallic iron, which may interfere with the catalytic reaction.We will continue to utilize XAFS and other techniques to deepen our understanding of the catalyst structure and elucidate the ORR mechanism. Furthermore, by developing non-platinum catalysts that exhibit seamless four-electron reduction reactions, we aim to suppress the generation of hydrogen peroxide and improve the durability of FC systems for further widespread use.References 1 R. Gokhale, L-K. Tsui, K. Roach, Y. Chen, M. M. Hossen, K. Artyushkova, F. Garzon, P. Atanassov, “Hydrothermal synthesis of platinum-Group-Metal-Free Catalysts: Structural Elucidation and Oxygen Reduction Catalysis”, ChemElectroChem, 5, 14, (2017), 1848-1853AcknowledgementsThe authors would like to express their sincere appreciation and celebration to Professor Dr. Plamen Atanassov of University of California, Irvine for his instruction to the catalyst synthesis. This work was performed under JSPS KAKENHI Grant Number JP22H02188. This work was also supported by the Research Program for Next Generation Young Scientists of “Network Joint Research Center for Materials and Devices: Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials”(235032). Figure 1