Scanning Electron Microscopy-energy Dispersive X-ray Spectroscopy Research Articles

Controlling cisplatin release by synergistic action of silver-cisplatin on monodispersed spherical silica for targeted anticancer and antibacterial activities

Recently, metal-based nanoformulations have been explored for targeted cancer therapeutics. In this study, synergistic therapeutic action of silver (Ag)-cisplatin nanoparticles loaded on monodispersed spherical silica (MSS) was investigated to evaluate anti-cancer (HCT-116 and HeLa cells) and antibacterial activity (P.aeruginosa, and S.aureus). Four different wt% of Ag (1, 2, 4 and 6 wt%) was loaded on MSS using a wet impregnation method. Characterization using XRD revealed the cubic phase of Ag nanoparticles with (111), (200) and (220) plane on MSS. The chemical state, dispersion of Ag and synergistic cohabitation with cisplatin (Cpt) was identified using diffuse reflectance UV–visible spectroscopy (DR-UV Vis), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM-EDS) and High-resolution transmission electron microscopy (HR-TEM). Zeta potential analysis indicated an increase in hydrodynamic diameter with high colloidal stability (–23.3 to −28.5 mV). The percentage cumulative Cpt release was studied using automated Franz cell and dialysis membrane technique. The effect of Cpt release on 4 wt%Ag impregnated on different shaped supports was investigated using cubic SBA-16 (Santa Barbara Amorphous), MFI type Ti-ZSM-5 (Zeolite Socony Mobil #5), hexagonal mesosilicalite, nanotube halloysite, and Ag-silicalite, respectively. Drug release study indicates that Ag loading controls the Cpt release. The kinetics of drug release for the different formulations was examined using Korsmeyers-Peppas model. Release constant (k) and release exponent (n) were utilized for the rate of drug release and diffusion mechanisms, respectively. The in vitro study revealed an efficient interaction of nanoformulations promoting both antibacterial and anticancer activities.

Colourants on the Persian architectural decorations from the 11th to the 15th century

AbstractOver 200 samples from colourants appeared in 50 monuments in Iran dated back to the 11th century up to the 15th century were identified using micro‐X‐ray fluorescence (μ‐XRF), micro‐Raman spectroscopy (μ‐Raman), polarized light microscopy (PLM), and scanning electron microscopy–energy dispersive X‐ray spectrometry (SEM‐EDS). Whereas red ochre, red lead, vermilion, and an organic red dye were identified as red colourants, ultramarine blue, azurite, and indigo were the blue colourants occurred in the wall decorations. In addition, atacamite was the only green pigment identified on the wall paintings and stucco decorations, and carbon black was identified as black pigment. We also show that gold leaf and tin foil have been used in gilding decorations. Furthermore, we were able to discern yellow ochre together with orpiment, natrojarosite, and crocoite in a number of architectural decorations. Moreover, we show that huntite and gypsum are used as white preparation layer of the wall decorations in Iran. Periods of emergence of particular pigments have been discussed and regional preferences in the use of certain pigments are argued. An extensive discussion is provided to compare the colourant appeared on wall decoration with those appeared on illuminated manuscripts in the Persianate world.

Identification of sources of coarse mode aerosol particles (PM10) using ATR-FTIR and SEM-EDX spectroscopy over the Himalayan Region of India.

This study attempts to examine the morphological, elemental and physical characteristics of PM10 over the Indian Himalayan Region (IHR) using FTIR and scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analysis. The study aimed at source identification of PM10 by exploring the inorganic ions, organic functional groups, morphology and elemental characteristics. The pollution load of PM10 was estimated as 63 ± 22 μg m-3; 53 ± 16 μg m-3; 67 ± 26 μg m-3 and 55 ± 11 μg m-3 over Mohal-Kullu, Almora, Nainital and Darjeeling, respectively. ATR-FTIR spectrum analysis revealed the existence of inorganic ions (SiO44-, TiO2, SO42-, SO3-, NO3-, NO2-, CO32-, HCO3-, NH4+) and organic functional groups (C-C, C-H, C=C, C≡C, C=O, N-H, C≡N, C=N, O-H, cyclic rings, aromatic compounds and some heterogeneous groups) in PM10 which may arise from geogenic, biogenic and anthropogenic sources. The morphological and elemental characterization was performed by SEM-EDX, inferring for geogenic origin (Al, Na, K, Ca, Mg and Fe) due to the presence of different morphologies (irregular, spherical, cluster, sheet-like solid deposition and columnar). In contrast, particles having biogenic and anthropogenic origins (K, S and Ba) have primarily spherical with few irregular particles at all the study sites. Also, the statistical analysis ANOVA depicts that among all the detected elements, Na, Al, Si, S and K are site-specific in nature as their mean of aw% significantly varied for all the sites. The trajectory analysis revealed that the Uttarakhand, Jammu and Kashmir, the Thar Desert, Himachal Pradesh, Pakistan, Afghanistan, Nepal, Sikkim, the Indo-Gangetic Plain (IGP) and the Bay of Bengal (BoB) contribute to the increased loading of atmospheric pollutants in various locations within the IHR.

Association and textural-compositional evolution of pyrite-organic matter in coals of the Tarakan, Barito, and Pasir Basins, Kalimantan, Indonesia

The Barito, Pasir, and Tarakan Basins in Kalimantan Island is the most extensive coal-bearing sedimentary basin in Indonesia, mined since 1989. The coal is notable in having high sulfur coal content, exceeding >10% in some cases, contributed by the presence of pyrite. The latter issue contributed to interest in the coal, forming economic mineral deposits hosted by the sedimentary pyrite and organic matter. Novel findings of this research providing valuable information of trace element behavior during the diagenetic conditions. This paper documents the textural and compositional evolution of pyrite-organic matter of coals using coal petrographic, proximate, ultimate, total sulfur content, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), electron probe micro analyser (EPMA), and Raman spectroscopy. Coals from Kalimantan are mainly characterized by medium-high sulfur content (>3%) and the maximum temperatures reached by organic matter during diagenesis are 166 ± 10 °C for the Pasir Basin, 136 ± 11 °C for the Barito Basin, and 132 ± 12 °C for the Tarakan Basin. Pyrite is mainly found as large size framboids (mostly >5 μm), indicating formation in the sedimentary layer with dysoxic bottom water conditions during early–late diagenetic stages. The framboidal pyrite was likely formed in detrovitrinite and gelovitrinite under topogenous mire conditions, due to the degradation of macerals and biochemical gelification, which provided the organic templates. High concentrations of trace elements (TE) of framboidal pyrite, such as 1) Cu, Ni, and Co in the Pasir Basin and 2) As in the Barito Basin, likely reflect the local sedimentary provenance and underlying basement rocks. Pyrite texture evolved with increasing diagenetic temperatures from 1) framboidal pyrite, 2) recrystallized framboidal pyrite rims, and 3) anhedral, anhedral-euhedral pyrite transition, and euhedral massive pyrite. This study shows a similar average TE concentrations of various pyrite texture, suggesting that the TEs are not remobilized during the evolution of pyrite at the diagenetic stages.

Synthesis of a Calcium Silicate Cement Containing a Calcinated Strontium Silicate Phase.

The positive effects of strontium on dental and skeletal remineralization have been confirmed in the literature. This study aimed to assess the properties of a calcium silicate cement (CSC) containing a sintered strontium silicate phase. The calcium silicate and strontium silicate phases were synthesized by the sol-gel technique. Strontium silicate powder in 0 (CSC), 10 (CSC/10Sr), 20 (CSC/20Sr), and 30 (CSC/30Sr) weight percentages was mixed with calcium silicate powder. Calcium chloride was used in the liquid phase. X-ray diffraction (XRD) of specimens was conducted before and after hydration. The setting time and compressive strength were assessed at 1 and 7 days after setting. The set discs of the aforementioned groups were immersed in the simulated body fluid (SBF) for 1 and 7 days. The ion release profile was evaluated by inductively coupled plasma-optical emission spectrometry (ICP-OES). Biomineralization on the specimen surface was evaluated by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Data were analyzed by the Kolmogorov-Smirnov test, one-way and mixed ANOVA, Levene's test, and LSD post hoc test (P < 0.05). Except for an increasement in the peak intensity of hydrated specimens, XRD revealed no other difference in the crystalline phases of hydrated and nonhydrated specimens. The compressive strength was not significantly different at 1 and 7 days in any group (P > 0.05). The setting time significantly decreased by an increase in percentage of strontium (P < 0.05). Release of Ca and Si ions significantly decreased by an increase in percentage of strontium (P < 0.05). SEM/EDS showed the formation of calcium phosphate deposits at 1 and 7 days. Incorporation of 10-30 wt% sintered strontium silicate phase as premixed in CSC can significantly decrease the setting time without compromising the compressive strength or biomineralization process of the cement.

The Source, Mobility and Fate of Bismuth (Bi) in Legacy Mine Waste, Yxsjöberg, Sweden

The usage of bismuth (Bi), a critical and strategic raw material, has increased in the last 10 years. At present, the knowledge of Bi geochemistry is too limited to develop accurate mine waste and water management strategies to prevent environmental impact. Therefore, its geochemistry was studied in historical tailings in Yxsjöberg, Sweden. Intact tailings cores and shore samples were geochemically and mineralogically analyzed. Groundwater was sampled between 2016 and 2021 and analyzed for 71 elements and (SO4, F, Cl). The results were correlated with metals and dissolved organic matter (DOC), which have been previously published. The total concentrations, sequential extraction and scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM–EDS) mapping indicated that Bi had been mobilized from the primary mineral bismuthinite (Bi2S3). In the oxidized tailings from both the cores and shore, Bi was hypothesized to have adsorbed to iron (Fe) (hydr)oxides, which prohibited high concentrations of Bi leaching into the groundwater and surface water. Dissolved Bi in groundwater was significantly correlated with DOC. In surface water, dissolved Bi was transported more than 5 km from the tailings. This study indicates that Bi can become mobile from legacy mine waste due to the oxidation of bismuthinite and either be scavenged by adsorption of Fe (hydr)oxides or kept mobile in groundwater and surface water due to complexation with DOC.

NFeS Embedded into Cryogels for High-Efficiency Removal of Cr(VI): From Mechanism to for Treatment of Industrial Wastewater.

Most studies have focused on complex strategies for materials preparation instead of industrial wastewater treatment due to emergency treatment requirements for metal pollution. This study evaluated sodium polyacrylate (PSA) as a carbon skeleton and FeS as a functional material to synthesize PSA-nFeS material. The characteristics and interactions of PSA-nFeS composites treated with hexavalent chromium were analyzed by means of various techniques, such as scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometry (FTIR), and atomic absorption spectroscopy (AAS). Adsorption-coupled reduction was observed to be the predominant mechanism of Cr(VI) removal. The feasibility of PSA-nFeS composites in reducing toxicity and removing of Cr(VI) from real effluents was investigated through column studies and material properties evaluation. The continuous column studies were conducted using tannery effluents to optimize feed flow rates, initial feed Cr(VI) concentration, and column bed height. The results revealed that PSA-nFeS composites are ideal for filling materials in portable filtration devices due to their lightweight and compact size.

Preparation and characterization of activated carbon from pine bark biomass for malachite green removal

ABSTRACT Using agricultural waste to prepare biomass materials to remove pollutants has become a research hotspot with the rise of the circular economy. This paper focused on the removal of Malachite Green (MG) as a cationic dye from an aqueous solution using adsorbents (ACBP1 and ACBP2) chemically activated from pine bark (PB) and phosphoric acid (H3PO4) as activated agent. Samples Characterisation was carried out by X-ray diffraction (XRD), Scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS), Fourier transform infrared spectroscopy (FTIR) and Zeta potential measurement. The MG adsorption study was carried out under the variation of several parameters such as pH, adsorbent dosage, contact time and medium temperature. The adsorption experimental capabilities of ACPB1 and ACPB2 for MG dye were 150.18 and 148.16 mg/g, respectively. The data fit the nonlinear equation of the Pseudo-first-order kinetic model for the two adsorbents ACBP1 and ACBP2 with correlation coefficients of 0.998 and 0.997, respectively, indicating that chemisorption controls adsorption. Temperature was found to have a slight impact on adsorption performance, with ACPB1 demonstrating a removal capacity of 184.510 mg/g at 25°C to 186.670 mg/g at 55°C. In addition, a theoretical study was performed using the Density Functional Theory (DFT) quantum calculation method to examine the interactions of reactive sites of the best adsorbent ACPB1 and the cationic dye MG. The theoretical results revealed that the – OH and – COOH groups of ACPB1 were involved in adsorption. The comparative investigation between the experimental and the theoretical results concluded that the ACPB1 adsorbent has a potential removal against the cationic MG dye.

Characterization of Hydrothermally Decomposed and Synthesized CaCO3 Reinforcement from Dead Snail Shells.

The development of new materials from marine resources presents a significant challenge due to the complexity of the associated materials and biology technologies. During this work, the snail shell, which naturally increases in thickness over time to protect the snail, has been identified as one of them. In this study, we investigated the use of powdered snail shells as a potential alternative to ceramics in the creation of customized composites. Our main objective is to explore the hydrothermal decomposition of the snail shell powder to remove undesirable components. To achieve this, we crushed and ground-washed dead snail shells and subjected them to hydrothermal decomposition using an autoclave and furnace at a temperature of 200, 220, 250, or 300 °C. We then analyzed the resulting samples using scanning electron microscope/energy-dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) techniques to determine changes in their composition and structure. Our findings demonstrate that all samples contained the elements Ca, C, and O, as confirmed by SEM/EDS results. XRD results show that hydrothermal decomposition at 250 °C led to good crystallization with maximum peak intensities observed at various diffraction angles. This indicates that the resulting material may have promising properties for use in composite materials. Overall, our study provides valuable insights into the use of snail shell powder as a potential material source for customized composites. Future studies could explore the optimization of the hydrothermal decomposition process and investigate the mechanical properties of the resulting materials to further develop this promising avenue of research.

Effects of various fillers on the thermal shock and fouling resistance characteristics of zirconia-based composite coatings for high-temperature applications

Composite coating technology has been extensively developed to meet industrial demands for coatings with specifications that exceed the capabilities of conventional coating technologies and that can function in extreme environments and high temperatures. The composite coating in this study is focused on materials that have hydrophobicity. To achieve this hydrophobicity, the coating must have at least one restrictive property: antifouling. In this research, antifouling coating materials based on certain zirconia ceramic composites (ZrO2) and fillers, such as boron nitride, MoS2, and graphite, are chosen. The substrate used is a low-carbon steel, which is used in high-temperature power plants. The slurry spray coating method is chosen, which is a simple and low-cost method. Thermal shock and fouling resistance tests are conducted, and the samples are further observed with Scanning Electron Microscopy-Energy-Dispersive X-ray Spectroscopy (SEM-EDS). The results show that the higher the hBN filler content in the zirconia composite coating is, the better the thermal shock and antifouling resistance levels. This phenomenon is indicated by the lower delamination of the coating after the thermal shock treatment and the lower fouling of sodium sulfate deposits on the surface of the coating after the antifouling treatment than before. The same result is shown by the zirconia composite coating with hybrid filler (hBN-MoS2-Graphite).

Spray Coated of ZnO Particles on ePA Nylon-Carbon Fiber Substrate and Its Photocatalytic Activity Evaluation

This work studies a simple deposition of ZnO particles on the ePA Nylon–Carbon Fiber substrate by sol-gel-spray-coating technique. The ZnO films were deposited on the substrate with deposition parameters such as suspension concentration, nozzle-to-substrate distance, nozzle size, coats, pump pressure, and deposition temperature. The ZnO gel suspension concentrations were varied (ZnO-0.06g/ml; ZnO-0.03g/ml), and the post-heated treatment was carried out at 120°C in vacuum condition. The temperature at 45°C during spray coating deposition was also applied to ZnO with the concentration of 0.03g/ml, which was noted as ZnO-0.03 TS. The films were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM/EDS), and Contact Angle (CA) to determine the structure, morphology, and hydrophilicity. The XRD pattern revealed that all samples have a hexagonal wurtzite structure. The SEM results showed that ZnO-0.06 relatively shows a dense surface, while ZnO-0.03 and ZnO-0.03 TS have a porous surface. The atomic ratio (Zn:O) revealed from the EDS measurement of the films was stoichiometric. The CA measurement showed that the film surfaces are hydrophilic. In addition, the photocatalytic activity was evaluated by the degradation of 2 mg/L methylene blue irradiated by sunlight for 180 mins—the photodegradation efficiencies were 88.37 %, 90.22 %, and 89,47 %, respectively.

Synthesis of TiO2/Fe2O3 Nanocomposites as Photocatalyst for Methyl Orange Degradation

Fe2O3/TiO2 composites were successfully synthesized using the sol-gel method. The photocatalytic performance of prepared nanocomposites to degrade methyl orange under UV light irradiation was systematically investigated. The Fe2O3 added and calcination temperature were varied to study their effect on psychochemical properties. Further, to study the effect of psychochemical properties of the prepared nanocomposites on photocatalytic activity, X-ray diffraction (XRD), and scanning electron microscope Energy Dispersive X-ray spectroscopy (SEM-EDS) characterization were conducted. The visible light active Fe2O3 photocatalyst managed to decrease the bandgap energy of the prepared composites from 3.32 eV to 1.95 eV. This decrease in the band gap energy led to the composite being more active under visible light and less active under UV light irradiation. A composite with 6% Fe2O3 content exhibits the smallest degradation efficiency of 14% in 180 min, while the pure TiO2 nanoparticles are 94%. The results in this study provided important implications for further research on the preparation of composite TiO2 with Fe2O3 co-catalyst showing a promising route for improving the visible light activity of photocatalysts.

Reactivated Spent Bleaching Earth as a New Path in Waste Resource Utilization for the Crude Palm Oil Bleaching Process

The palm oil refining process usually uses adsorbents. The commonly used adsorbent is Bleaching Earth. However, this raises a new problem: hazardous waste in the refining process, namely Spent Bleaching Earth (SBE). For this reason, one of which is the utilization of SBE as an adsorbent through a reactivation process. This study aims to determine the characterization of RBE produced from the microwave reactivation process and acid solution as an adsorbent in the palm oil (CPO) bleaching process. The SBE reactivation process was carried out using microwaves and sulphate acid solution at concentrations 3N. RBE characteristics were analyzed using Scanning Electron Microscopy - energy dispersive X-ray spectroscopy (SEM-EDS) and Brunner Emmet Teller (BET) - Barrett-Joyner-Halenda (BJH). The resulting RBE characteristics include surface area, pore volume, and pore size of 436,820 m2/g, 0.544 cc/g, and 2.488 nm, respectively. Patricelli model is more appropriate to use to explain the mechanism of the SBE desorption process using the MAE method with the coefficient of determination value of 0.9931. The palm oil adsorbed using RBE has 10R/20Y/0.9W of color quality, 3.93% free fatty acid number, and 11.61 meq O2/kg peroxide number. In this study, SBE was successfully converted into RBE by microwave reactivation process, and the excellent performance of RBE in palm oil bleaching was verified. This research not only helps to solve the environmental problems in the process of palm oil refining but also provides a new way for waste resource utilization.

THE POWDER OF Co64Nb30B6 OBTAINED BY MECHANICAL ALLOYING

This work aims to synthesize the alloy Co64Nb30B6 through mechanical alloying using a planetary ball mill. A disc rotation per minute and a ball/powder weight ratio of 300 rpm and 10:1 were used, with a milled time of 10 h, respectively. The characterization of the Co64Nb30B6 alloy was performed by X-ray diffraction (XRD), examined by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS), thermoanalytical techniques (TGA/DTA), vibrating sample magnetometer (VSM) and confirmed by Braunauer, Emmet e Teller (BET) method type IV isotherms with a hysteresis loop for mesoporous materials. The results indicated that the evolution of the amorphous phase in the Co64Nb30B6 composition through the mechanical alloying process exhibited good soft magnetic properties with the addition of the metalloid element B and its excellent unique ferromagnetic properties. Through thermoanalytical analysis (TGA/DTA), it was shown that at higher temperatures, Co and Nb ions are oxidized by the environment and, therefore, the mass can be slightly increased to 14.9% and a probable contribution of boron in evolution stability thermal and magnetic in the amorphous phase, respectively. This suggests that the newly developed high-performance amorphous alloy Co64Nb30B6 has great application potential.

Fe–Mo/Kaolin Catalyst Optimization and Characterization for the Production of Carbon Nanotube Using the Wet Impregnated Method

Abstract: The synthesis of the bimetallic Fe–Mo/kaolin catalyst for carbon nanotube (CNT) production involves the pre-calcination and calcination processes, employing the wet impregnated method. In the pre-calcination stage, we explored the effects of synthesis parameters such as oven drying temperature, mass of kaolin, and heating time using a 23 factorial experimental design, ultimately obtaining the highest yield sample. In the calcination phase, the effect of temperature and heating time using a 22 factorial experimental design was examined. The as-prepared nanoparticles were characterized by scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDS), thermogravimetric analysis (TGA), differential thermal analysis (DTA), x-ray diffraction (XRD), and Brunauer-Emmet-Teller (BET). SEM/TGA revealed a well-dispersed metallic particle on the kaolin support and its ability to maintain high thermal stability. XRD analysis of the catalyst confirmed its crystal nature and the presence of mixed oxides of different intensities, conducive to CNT growth. The optimum yield obtained after oven drying was 75.25%. At the optimum calcination temperature of 300° C and calcination time of 16 hours, BET analysis determined the surface area and pore volume. For kaolin, the surface area and pore volume were 1.932x102 m2/g and 1.762x10-1 cc/g, respectively. The optimal calcine sample showed increment for both the surface area (3.103 x102 m2/g) and the pore volume (2.459 x10-1cc/g) making it more suitable for CNT production. Lastly, statistical analysis showed that heating time, calcination time, temperature, and mass of kaolin have a significant influence on the catalyst yield in CNT. Keywords: catalyst, wet impregnation, optimization, carbon nanotubes.

GSR Analysis by Spectrophotometry Method in Forensic Chemistry

This study was conducted to analyze residual shots from forensic chemistry applications. The entire analysis process was evaluated with Scanning Electron Microscopy/Energy Dispersive X-Ray Spectroscopy (SEM/EDS) and, Graphite Furnace Atomic Absorption Spectrometry (GFAAS)devices, which are among the methods for obtaining efficient results, and positive results were tried to be obtained by comparison. Following the study, it was discussed which results were more appropriate; in particular, the samples' appropriateness for reanalysis was underlined. The presence of shot residues on all samples was determined in the analyses performed with the SEM/EDS device. When the same samples were analyzed with the GFAAS device, the results remained below the threshold value of 10 μg/L, which is the antimony concentration indicating the presence of shot residues. It should be noted that the values we obtained may vary with the size and weight of the shot residue particles. Due to the ease of sample collection, the capacity to identify elements other than gunshot residues on the sample under examination, and the circumstances surrounding the determination of particles below the threshold value, the analysis method utilizing the SEM/EDS device has been deemed more suitable despite its higher cost.

Improving Stability of CO2 Electroreduction by Incorporating Ag NPs in N-Doped Ordered Mesoporous Carbon Structures.

The electroreduction of carbon dioxide (eCO2RR) to CO using Ag nanoparticles as an electrocatalyst is promising as an industrial carbon capture and utilization (CCU) technique to mitigate CO2 emissions. Nevertheless, the long-term stability of these Ag nanoparticles has been insufficient despite initial high Faradaic efficiencies and/or partial current densities. To improve the stability, we evaluated an up-scalable and easily tunable synthesis route to deposit low-weight percentages of Ag nanoparticles (NPs) on and into the framework of a nitrogen-doped ordered mesoporous carbon (NOMC) structure. By exploiting this so-called nanoparticle confinement strategy, the nanoparticle mobility under operation is strongly reduced. As a result, particle detachment and agglomeration, two of the most pronounced electrocatalytic degradation mechanisms, are (partially) blocked and catalyst durability is improved. Several synthesis parameters, such as the anchoring agent, the weight percentage of Ag NPs, and the type of carbonaceous support material, were modified in a controlled manner to evaluate their respective impact on the overall electrochemical performance, with a strong emphasis on operational stability. The resulting powders were evaluated through electrochemical and physicochemical characterization methods, including X-ray diffraction (XRD), N2-physisorption, Inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM), SEM-energy-dispersive X-ray spectroscopy (SEM-EDS), high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), STEM-EDS, electron tomography, and X-ray photoelectron spectroscopy (XPS). The optimized Ag/soft-NOMC catalysts showed both a promising selectivity (∼80%) and stability compared with commercial Ag NPs while decreasing the loading of the transition metal by more than 50%. The stability of both the 5 and 10 wt % Ag/soft-NOMC catalysts showed considerable improvements by anchoring the Ag NPs on and into a NOMC framework, resulting in a 267% improvement in CO selectivity after 72 h (despite initial losses) compared to commercial Ag NPs. These results demonstrate the promising strategy of anchoring Ag NPs to improve the CO selectivity during prolonged experiments due to the reduced mobility of the Ag NPs and thus enhanced stability.

4D evolutions of cracks, voids, and corrosion products in reinforced concrete materials

This research paper presents a comprehensive investigation into the corrosion process in reinforced concrete structures using advanced analytical techniques, namely non-destructive X-ray computed tomography (CT) imaging, scanning electron microscopy (SEM) images, energy dispersive x-ray spectrometry (EDS), and Raman spectroscopy. The CT image analysis allowed for the identification and quantification of pore structures, crack propagation, and corrosion progression at different stages of corrosion. CT scanning and data analysis offer valuable 4D (3D spatial + time) insights into corrosion in reinforced concrete, revealing changes in pore sizes, with smaller pores increasing and larger pores decreasing as corrosion progresses. Our investigation reveals dynamic changes in reinforced concrete pores during the accelerated corrosion test leading to new pore formation and cracking. The research identifies two distinct types of cracks: one filled with corrosion products and the other, zipper-like cracks, resulting from the connection of deformed pores without corrosion products. The SEM images and EDS analysis confirmed the absence of corrosion products within these unique zipper cracks, suggesting a different mechanism of crack formation compared to the first type of cracks. The results revealed two distinct categories of corrosion products: iron oxides and iron hydroxides, with their distribution correlated to the duration of accelerated corrosion testing. The integration and verification of results from X-ray CT imaging and Raman spectroscopy established a comprehensive understanding of corrosion-induced damage in the reinforced concrete specimen, shedding light on complex interactions among different corrosion products during the corrosion process. These findings offer crucial insights for better understanding of the corrosion process in reinforced concrete paving the way for future development of effective treatments and strategies to mitigate corrosion impact.

Effect of process variables on leaching behavior and kinetics of silver element from waste photovoltaic modules

In order to achieve efficient leaching of silver, in waste photovoltaic panels, the leaching process using nitric acid was investigated. The effects of nitric acid concentration, leaching time, solid–liquid ratio, and leaching temperature on the silver leaching rate were examined. The response surface method was used to establish an experimental model for analyzing and optimizing the leaching experiment. The results showed that the nitric acid concentration had the most significant effect on the leaching rate. The leaching rate of 98.02% was achieved under the following optimal leaching conditions: a nitric acid concentration of 18%, a leaching time of 32 min, a solid–liquid ratio of 1:30, and a leaching temperature of 60 °C. According to the shrinkage nuclear model, the leaching kinetics of silver using nitric acid followed a chemical reaction-controlled process with an apparent activation energy of 42.26 kJ/mol. Scanning electron microscopy–energy-dispersive x-ray spectrometry results of minerals before and after leaching confirmed the efficient recovery of silver in waste photovoltaic cells.

Production of Cellulosic Microfibers from Coffee Pulp via Alkaline Treatment, Bleaching and Acid Hydrolysis.

The present work deals with the production of cellulosic microfibers (CMFs) from coffee pulp. The experimental development corresponds to an experimental design of three variables (concentration, temperature and time) of alkaline treatment for delignification, finding that concentration, temperature and time were the most representative variables. Higher delignification was achieved by bleaching cellulosic fibers, followed by acid hydrolysis, thus producing cellulosic fibers with an average diameter of 5.2 µm, which was confirmed using scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS). An X-ray diffraction (XRD) analysis revealed, via the crystallinity index, the presence of Type I cellulose and removal of lignocellulosic compounds through chemical treatments. The proximate chemical analysis (PChA) of coffee pulp helped to identify 17% of the crude fiber corresponding to the plant cell wall consisting of lignocellulosic compounds. The initial cellulose content of 26.06% increased gradually to 48.74% with the alkaline treatment, to 57.5% with bleaching, and to 64.7% with acid hydrolysis. These results attested to the rich cellulosic content in the coffee pulp.