Scanning Electron Microscopy Coupled With Energy Dispersive X-ray Spectroscopy Research Articles

Influence of the concentration of KOH-based aqueous electrolyte on the electrochemical behavior of NiO thin film

In this research, we explored the influence of varying concentrations of KOH electrolyte (0.5, 1, and 2 M) on the electrochemical characteristics of Nickel Oxide (NiO) thin film. The deposition of NiO material onto glass and Fluor Tin Oxide (FTO) coated glass substrates was achieved through the chemical spray pyrolysis method. Subsequent examinations encompassed structural, morphological, optical, and electrochemical assessments, employing X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM-EDS), UV-VIS-NIR spectrophotometry, and cyclic voltammetry (CV), respectively. XRD analysis unveiled a polycrystalline cubic structure of NiO with a preference for orientation along the (111) plane. Raman spectroscopy confirmed the presence of the NiO phase, whereas SEM images depicted the emergence of interconnected nanograins with occasional minor cracks. EDS examination and elemental mapping further substantiated a homogeneous dispersion of elements. Optical analysis disclosed a band gap energy of 3.54 eV and an average transmittance of 71 % in the visible range. Electrochemical analysis indicated that the specific capacitance reached its peak at [1 M] (70 F. g−1). The [2 M] electrolyte exhibited the highest optical modulation (29 %), the most substantial charge density (Qi = 9.5 mC/cm2), and the most favorable switching kinetics. However, the coloration efficiency slightly decreased from 30.94 cm2/C in [1 M] to 30.47 cm2/C in the [2 M] solution, despite these improvements.

Extraction of metal values from iron-rich mine tailings via chloridized roasting and water leaching

The surge in mining and mineral processing to meet metal demand has led to accumulation of mining by-products like tailings, waste rocks, and acid mine drainage, containing high iron, copper, nickel, and zinc concentrations. These residues pose environmental threats. The concept of technospheric mining aims to repurpose these wastes for beneficial uses, reducing disposal and ecological impact while benefiting stakeholders. Within this context, the present investigation focuses on the discriminative retrieval of copper and nickel from mine tailings characterized by elevated iron content. This is achieved through formulation of an energy-efficient technique designed to surmount the challenge of iron co-extraction during hydrometallurgical processes aimed at extracting and recuperating metal values from intricate phases. The proposed method entails the amalgamation of mine tailings and solid NH4Cl in a stoichiometric ratio of 1:2, followed by roasting at 300 °C for a span of 1 h. Application of chloridized roasting orchestrates the transformation of copper and nickel into soluble metal chlorides, while concurrently inducing conversion of iron into a stable iron oxide state. Subsequent stages encompass the separation of copper and nickel from the water leach liquor, achieved through solvent extraction techniques utilizing LIX84I and Cyanex 272 as extractants. Rigorous characterization efforts, employing techniques such as X-ray Diffraction (XRD) and Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM-EDS), are undertaken to elucidate the attributes of the raw material and solid residues. Remarkably, the comprehensive isolation of copper, nickel, and iron is realized without generation of any effluents, ensuring preservation of environmental equilibrium.

Interdisciplinary methodology for the characterisation of archaeological metal grave goods from the Museum of Patagonia by PIXE, DRX, and SEM/EDS

AbstractWe present a study of a selection of metal ornaments belonging to archaeological funerary goods from Patagonic Indigenous groups. They are part of the ‘Andrés Giai’ Collection, under the guard of the Museum of Patagonia (Nahuel Huapi National Park [PNNH]; National Parks Administration [APN]), Argentina. The absence of contextual information and its current conservation status motivated the design of an interdisciplinary methodology to develop an Integral Conservation Plan that considered the selection of analytical techniques. Here, we implemented complementary nondestructive characterisation techniques such as particle induced X‐ray emission (PIXE), X‐ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive X‐ray spectroscopy (SEM/EDS). We developed a methodology enabling us to characterise each piece with respect to its metallic composition and degradation products, and in certain cases, their manufacturing process. These findings have contributed with essential information for the tailored conservation treatment proposal. Moreover, they provided key information in regard to the reconstruction of contextual data for each piece. In addition, the methodology proposed for the Integral Conservation Plan takes into account an optimisation of the techniques to be used in order to minimise unnecessary handling of goods whilst ensuring an appropriate use of technological and economic resources whilst minimising time on potentially unconclusive measurements and results.

Synergistic advantages of volcanic ash weathering in saline soils: CO2 sequestration and enhancement of plant growth

Carbon dioxide (CO2) is a primary greenhouse gas that has experienced a surge in atmospheric concentration due to human activities and lifestyles. It is imperative to curtail atmospheric CO2 levels promptly to alleviate the multifaceted impacts of climate warming. The soil serves as a natural reservoir for CO2 sequestration. The scientific premise of this study is that CO2 sequestration in agriculturally relevant, organically-deficient saline soil can be achieved by incorporating alkaline earth silicates. Volcanic ash (VA) was used as a soil amendment for CO2 removal from saline soil by leveraging enhanced silicate rock weathering (ERW). The study pursued two primary objectives: first, we aimed to evaluate the impact of various doses of VA, employed as an amendment for organically-deficient soil, on the growth performance of key cultivated crops (sorghum and mung bean) in inland saline-alkaline agricultural regions of northeastern China. Second, we aimed to assess alterations in the physical properties of the amended soil through mineralogical examinations, utilizing X-ray diffraction (XRD) and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) analyses, quantifying the increase in inorganic carbon content within the soil. In the potting tests, mung bean plant height exhibited a noteworthy increase of approximately 41 % with the addition of 10 % VA. Sorghum plant height and aboveground and belowground biomass dry weights increased with VA application across all tested doses. At the optimal VA application rate (20 %), the sorghum achieved a CO2 sequestration rate of 0.14 kg CO2·m−2·month−1. XRD and SEM-EDS analyses confirmed that the augmented inorganic carbon in the VA-amended soils stemmed primarily from calcite accumulation. These findings contribute to elucidating the mechanism underlying VA as an amendment for organically-deficient soils and provide an effective approach for enhancing the carbon sink capacity of saline soils.

Investigating the Middle Iron Age ceramics of Van Fortress through multi-analytical techniques

This work presents the characterization results of Middle Iron Age pottery fragments excavated in Van Fortress, the historical capital of the Urartu Kingdom, located on the eastern coast of Lake Van in Turkey. A multi-analytical approach combining optical microscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR) has been employed to investigate the mineralogical composition of ceramics. Micro-Raman spectrometer was also used for the characterization of the pigments used for decoration. The data collected from the analyses offered information on the minerals that were discovered in the ceramics, as well as the temperature at which the ceramics were fired and the atmosphere that they were exposed to. The existence of hematite suggests that they were subjected to firing in an oxidizing environment, with the exception of one sample, which has a sandwich shape characterized by a red-edge and a black center, indicating exposure to both reducing and oxidative atmospheres during the fire process. The ceramics utilized in this investigation are hypothesized to have been crafted from elemental substances procured from two to three distinct clay origins.

Fabrication of peptide-encapsulated sodium alginate hydrogel for selective gallium adsorption

Peptides are recognized as promising adsorbents in metal selective recovery. In this study, the designed gallium-binding peptide H6GaBP was immobilized by the polysaccharide polymer sodium alginate (SA) for gallium recovery. The synthesized H6GaBP@SA microspheres exhibited a maximum adsorption capacity of 127.4 mg/g and demonstrated high selectivity for gallium at lower pH values. The adsorption process aligned well with the pseudo-second-order equation and Langmuir model. To elucidate the adsorption mechanism, a comprehensive characterization including molecular docking, scanning electron microscope coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and thermogravimetry analysis (TGA), were conducted. These analyses revealed that gallium ions were initially adsorbed through electrostatic interaction by H6GaBP@SA, followed by a cation exchange reaction between Ga(OH)2+ and Ca2+, as well as coordination between gallium and histidine residues on the peptide. Moreover, the H6GaBP@SA exhibited improved thermal stability compared to sole sodium alginate microspheres, and the coordination of gallium with peptides can also defer the decomposition rate of the adsorbents. Compared to other adsorbents, the peptide-encapsulated hydrogel microspheres exhibited superior gallium selectivity and improved adsorption capacity, offering an environmentally friendly option for gallium recovery.

Shrimp shell waste-modified natural wood and its use as a reservoir of corrosion inhibitor (L-arginine) for brass in 3% NaCl medium: Experimental and theoretical studies

The primary objective of this study is to harness the valuable properties of natural wood waste (NWW) and a shrimp shell extract known as chitosan (Cs). In this context, and in order to prevent rapid consumption of the L-arginine inhibitor (Arg), it was encapsulated in NWW by means of a chitosan polymer. The resulting modification was verified using X-ray diffraction (XRD), which revealed the presence of chitosan and reflections corresponding to arginine in the modified wood. Additional techniques, including Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (SEM-EDS), were used for comprehensive characterization. The corrosion inhibition effect resulting from the application of NWW-Cs-Arg composite was investigated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The obtained results revealed that, at an optimal concentration of 2 g/L and under ambient temperature conditions (298 K), this composite demonstrated a high level of corrosion inhibition, reaching up to 75 %, exhibiting cathodic behavior. Quantum chemical calculations were also carried out to predict the active sites in the used inhibitor. The methodology employed was based on the B3LYP/6-311G++(d,p) theory in an aqueous environment. Parameters such as frontier molecular orbitals (HOMO and LUMO), global reactivity descriptors, molecular electrostatic potential (MEP), and Mulliken population have been studied to assess local reactivity and identify reactive centers and potential nucleophilic and electrophilic attack sites. Weak interactions were analyzed using topological approaches (ELF, LOL, and NCI). It is noteworthy that the arginine molecule interacts through hydrogen bonds between its guanidine group and the hydroxyl groups present in the wood and chitosan residues. Meanwhile, the amine groups of chitosan promote charge transfer between arginine and copper atoms, particularly through the NH groups in the alpha position relative to the C = O group.

Feroxyhyte - from synthesis and characterization to application.

Feroxyhyte (δ-FeOOH) was synthesized and characterized using X-ray diffractometry (XRD), simultaneous thermal analysis (STA), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), and low-temperature nitrogen adsorption-desorption measurements. Its potential application as adsorbent of an anionic and cationic dyes such as C.I. Acid Violet 1 (AV1) and C.I. Basic Blue 3 (BB3) was investigated by determining the adsorption capacities based on the Langmuir (36.6 mg/g for AV1 and 187 mg/g for BB3), Freundlich and Dubinin-Radushkevich isotherm models. Adsorption of AV1 and BB3 by δ-FeOOH drops with the presence of additives such as cationic and anionic surfactants (CTAB, SDS) and ionic polymers (PAA, PEI). The surface and electrokinetic properties of examined suspensions were also described. They include determination of the solid surface charge density and the zeta potential, as well as values of point of zero charge and isoelectric point of feroxyhyte particles without and with adsorbed layers of organic substances. Their analysis made possible to propose the most probable structure of electrical double layer formed at the iron mineral/aqueous solution interface.

Hydration mechanism of red mud-fly ash based geopolymer

Geopolymer is considered the most promising alternative to Portland cement due to its excellent performance and low cost. In this study, the hydration mechanism of red mud-fly ash based geopolymer (RFG) was analyzed using low-field nuclear magnetic resonance (LNMR), rheological tests, Fourier transform infrared spectrometry (FT-IR), isothermal calorimetry, and scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDS). The compressive strength of RFG falls with increasing dosages of red mud, and initially increased and subsequently decreased with the increment of SiO2/Na2O ratio. According to the results of LNMR and rheological tests, the geopolymerical hydration process of RFG is divided into three phases: an induction phase, an acceleration phase, and a stabilization phase. When the SiO2/Na2O ratio of the activator is lower than 2.4, it has an activation effect on the cementitious material, and the optimal value is 2.1. The hydration rate of the cementitious material decreases as the dosage of red mud is increased. The slurry transitions from the Herschel-Barkley model to the Bingham fluid model as the hydration reaction advances. The hydration products is verified with different red mud dosage and SiO2/Na2O ratio by SEM-EDS. The findings of this study enrich our understanding of RFG, promote its engineering applications, and improve the utilization efficiency of red mud.

Efficient extraction of platinum(IV) using tertiary-amine groups functionalized thiacalix[4]arene as extractant

In the present study, the extraction performance and complexation mechanism of p-di-ethyl-amino-methyl-thiacalix[4]arene (L) toward Pt(IV) in a hydrochloric acid system were investigated. The effects of various parameters including solution pH, L to Pt(IV) mole ratio, Cl− concentration, acidity and reaction time on the complexation process of L with Pt(IV) were systematically investigated. The experimental results indicated that L has excellent complexation ability toward Pt(IV) that about 90 % of Pt(IV) could be extracted within 2 min under the optimal conditions. Moreover, L could selectively extract Pt(IV) from the HCl system containing multiple competing ions such as Ce(III), Zr(IV), La(III), Fe(III), Ni(II), Mg(II), and Al(III). The complexation mechanism between L and Pt(IV) was further clarified by slope analysis, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), and proton nuclear magnetic resonance (1H NMR) titrations. Theoretical analysis of thermodynamics, complexation structure and intermolecular interactions between L and Pt(IV) during the solvent extraction process were performed through density functional theory (DFT) calculations. The results showed that the protonation of L occurs first to form the complex of L·2HCl, which further reacts with PtCl62− forming the complex of L·2H+·PtCl62− through anion-exchange, achieving the efficient and selective extraction of platinum.

Exploring the synergistic effects of calcium chloride modification on stem bark eucalyptus biochar for Cr(VI) and Pb(II) ions removal: Kinetics, isotherm, thermodynamic and optimization studies

In this study, stem bark eucalyptus was subjected to pyrolysis modification to produce modified biochar. The modified biochar (MSBEB) was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray Diffraction (XRD), and Brunauer–Emmett–Teller (BET) techniques. The impact of adsorption process variables such as temperature, adsorbent dosage, pH and contact time on the metals ion removal efficiency were investigated. The optimum conditions for maximum removal of Cr(VI) and Pb(II) ions were determined as 45.20 °C, 0.12 g/L, and 120.5 min through optimization process. The excellent performance of the modified biochar can be attributed to its porous structure, surface area, surface chemistry and crystallinity as supported by SEM, BET, FTIR and XRD analysis. However, based on the high correlation coefficient (R2), low values of chi square (χ2) and sum of square error (SSE), the Freundlich isotherm and Pseudo-second order kinetics provided the best fit, suggesting chemisorption as the dominant mechanism. Thermodynamic analysis indicated an endothermic, spontaneous, and feasible reaction.

(Invited) Electrodeposition of Manganese Arsenides (MnxAs) as Promising Candidates in Spintronics

Spintronics is a new branch of electronics in which the spin of the electrons as well as their charge is manipulated to produce a desired outcome. Spintronic devices are particularly attractive for memory storage and magnetic sensor applications, and potentially for quantum computing where the electron spin would represent a bit of information. Nowadays many efforts are made to increase the efficiency and lower the production costs of these materials, among others the use of molecular inorganic compounds and cheap preparation techniques [1].Most of these layers are synthesized with physical and/or vapor phase techniques [2] which allow to obtain materials with a very few defects, but which are complex to manage and typically very expensive. For this reason, in this study we have searched for a way to electrochemically deposit a compound with interesting spintronic properties in the aqueous medium. In fact, electrodeposition is notoriously a very cheap, versatile and easily scalable technique.With this purpose Mn-As system was selected thanks to its good magnetic and transport properties to be used as building blocks for spin valve [3]. MnAs has potential applications in spintronics, for electrical spin injection into GaAs and Si based devices [4] and DFT simulations predict that Mn2As and Mn3As have a low magnetization saturation and a high spin polarization at the Fermi-level [5]. Starting from MnSO4 and NaAsO2 precursors solutions with various concentrations, supporting electrolytes and pH were tested.The electrochemical behaviour of the precursors was investigated with cyclic voltammetries and both potentiostatic as well as galvanostatic deposition were carried out. The deposits obtained were morphologically and compositional characterised with scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray fluorescence spectroscopy (XRF), the chemical states were analysed with X-ray photoelectron spectroscopy (XPS), the crystalline structure was investigated with X-ray diffraction measurements (XRD). The preliminary magnetic and transport measurements evidence the promising properties of this deposition process to provide spinfiltering materials.The authors acknowledge Regione Toscana POR CreO FESR 2014-2020 – azione 1.1.5 sub-azione A1 – Bando 1 “Progetti Strategici di ricerca e sviluppo” which made possible the project “RAM-PVD” (CUP 3647.04032020.157000057_1225).

Effective extraction of nickel and cobalt from sintered nickel alloy via reduction roasting and leaching

In this work, a carbothermic reduction technique is developed to improve the extraction of valuable metals from sintered nickel alloys by atmospheric acid leaching. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) analyses indicate that NiO in the sintered nickel alloy and the NiO coated by Ni2O3 hinders further dissolution of nickel. Nickel oxides can be transformed into easily leached metallic nickel by carbothermic reduction. The reduction roasting was investigated and optimized by thermodynamic analysis, thermogravimetry-mass spectrometry, XRD, and response surface methodology (RSM). The results show that the leaching efficiencies of nickel and cobalt are respectively increased from 80.34% and 69.92% to 98.65% and 96.71% after the reduction roasting under the optimized conditions: 935 °C of temperature, 50 min of time, and 29.9% of carbon dosage. The leaching of nickel was optimized by single-factor test method and the optimum conditions have been established as: 150 g/L of H2SO4 concentration, 25% of H2O2 dosage, 10 mL/g of liquid–solid ratio, 400 rpm of stirring speed, 80 °C of temperature, and 80 min of time. The kinetic analysis of leaching process shows that the activation energies of nickel and cobalt leaching are 20.71 kJ/mol and 16.33 kJ/mol, respectively, indicating that the leaching process is an internal diffusion control process. This study provides a feasible and effective approach to extract nickel from sintered alloys.

Role of Reservoir Brine and Rock in Modulating Asphaltene Stability: Insights from Experimental Analysis

Summary The stability of asphaltenes in crude oil is influenced by various factors, including interactions with reservoir components such as brine and rock formations. While previous research has focused on pressure and temperature effects, a comprehensive understanding of the combined impact of brine and reservoir rock on asphaltene stability is lacking. This study investigates the individual and combined influences of brine and rock formations on asphaltene stability. First, 11 crude oil samples from diverse locations were characterized using API gravity, viscosity, and saturates, aromatics, resins, and asphaltenes (SARA) fraction analysis. The elemental composition of the crude oils, including carbon, hydrogen, nitrogen, and various metals, was determined. The surface properties of asphaltenes were analyzed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). The interaction between asphaltenes and deionized water was examined through zeta potential, particle size, conductivity, and pH measurements. The behavior of asphaltenes in an 8,000 ppm NaCl solution was also investigated. The SEM analysis revealed the presence of inorganic content on the surfaces of asphaltenes, indicating interactions between asphaltenes and reservoir rock. A strong correlation between the zeta potential and sulfur content of asphaltenes was observed, highlighting the influence of sulfur compounds on surface charge and stability in heavy crudes. Additionally, the correlation between total dissolved solids (TDS) content and alkaline Earth metals and alkali metals in asphaltenes confirmed interactions between asphaltenes and reservoir brine. This interaction is likely influenced by the composition and properties of both the brine and reservoir rock. The presence of electrical charges on the asphaltene surfaces, as determined by zeta potential measurements, further supports the role of electrostatic interactions in asphaltene stability. The low precipitation tendency observed for most asphaltene samples, coupled with the abundance of negatively charged particles, underscores the importance of electrical charges in controlling stability. This study provides novel insights into asphaltene stability, highlighting the significance of surface charge and elemental composition. The results demonstrate the substantial impact of both reservoir brine and rock formations on asphaltene stability in crude oil. Further research is needed to unravel the complex mechanisms underlying these interactions and their implications in diverse reservoir environments.

Structural and Thermal Examinations of Polyamide Modified with Fly Ash from Biomass Combustion.

This paper presents the results of examinations of the structure and crystallinity of polyamide (PA6) modified with fly ash from biomass combustion in a fluidized-bed boiler. Composites based on a PA6 matrix were examined. They contained 5, 10, and 15 wt% fly ash. Fourier-transform infrared with attenuated total reflectance spectroscopy (FTIR-ATR) was used to identify the characteristic functional groups present in the chemical structure of polyamide and composites based on its matrix. Structural analysis was performed using a differential scanning calorimeter (DSC) and microscopic examinations. Analysis of the values of thermal effects determined using the DSC technique allowed for the evaluation of the degree of crystallinity of the materials studied. Polyamide is usually considered to be a two-phase system consisting of crystalline and amorphous regions. The addition of the filler in the form of fly ash reduced the degree of crystallinity of the studied specimens. Based on the FTIR-ATR spectra and the recorded DSC curves, it was found that the α-phase was the dominant crystalline phase in the studied materials. Microscopic examinations were conducted to analyze the microstructure of the materials, providing information on the distribution and shape of the filler particles. Most of the particles ranged in size from a few to tens of micrometers. Furthermore, the use of scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) allowed for the analysis of the distribution of chemical elements in selected filler particles.

REE Geochemical Characteristics of the Huri Karst-Type Bauxite Deposit, Irano–Himalayan Belt, Northwestern Iran

The Huri bauxite deposit is located 40 km northwest of Maragheh City, East Azerbaijan province, northwestern Iran. Bauxite horizons at Huri develop within karstic depressions and sinkholes of carbonate footwalls of the Ruteh Formation, overlain by carbonate of the Elika Formation. Powder X-ray diffraction (PXRD) and scanning electron microscope, coupled with energy dispersive X-ray spectroscopy (SEM-EDS) analyses show that the Huri bauxite ores consist of hematite, diaspore, kaolinite, and lesser amounts of halloysite, pyrophyllite, illite, goethite, clinochlore, amesite, rutile, zircon, and monazite. Based on geochemical studies (Eu/Eu* vs. Sm/Nd and U/Th bivariate diagrams), basalt rocks interbedded in limestone of the Ruteh Formation are the possible precursor rocks of the Huri bauxite deposit. The pH variations of weathering solutions, fluctuations in the groundwater table level, the function of carbonate bedrock as a geochemical barrier, simultaneous precipitation of Fe-bearing minerals, and preferential scavenging of light rare earth elements (LREE) by hematite played an important role in the fractionation of LREE from heavy rare earth elements (HREE) in the Huri bauxite ores. Fluctuations in groundwater table level, increasing pH of acidic solutions percolating downward, preferential adsorption of Ce onto hematite at the base of the profile, and the possible presence of Ce-bearing fluorocarbonates played an important role in increasing Ce anomaly from the top of the profile downward.

Development of a novel hydrophilic SiO2/PVDF Janus membrane via different modification methods for robust antiwetting and antifouling membrane distillation

The development of novel membrane distillation (MD) membranes with high resistance to wetting and fouling has a great importance for the treatment of surfactant or oil-containing wastewater. In this study, superwettable Janus membranes were produced using hydrophilic silica nanoparticles (SiO2 NPs) via blending phase inversion (M1), delayed phase inversion (M2), and spray coating (M3) methods. Scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM/EDS) and Fourier transform infrared spectrometry (FTIR) analysis showed that SiO2 NPs were successfully deposited on the top layers of the membranes, while no SiO2 NPs were detected on the bottom layers. Furthermore, underwater superoleophobic properties were achieved for M2 and M3 membranes, while M1 membrane showed a satisfactory underwater oleophobicity. In MD filtration tests, the M2 membrane exhibited the highest membrane wetting and fouling resistance, followed by the M1 membrane. However, the sprayed SiO2 NPs coating layer on the M3 membrane did not remain stable, resulting in a similar permeate water flux and rejection profiles to the pristine membrane after a short time. This study indicates that Janus membranes fabricated by blending and delayed phase inversion methods could be a strong candidate in MD for the treatment of complex wastewater containing surfactants and oil.

Photocatalytic Activity and Biocide Properties of Ag-TiO2 Composites on Cotton Fabrics.

Composites of Ag and TiO2 nanoparticles were synthesized in situ on cotton fabrics using sonochemical and solvothermal methods achieving the successive formation of Ag-NPs and Ti-NPs directly on the fabric. The impregnated fabrics were characterized using ATR-FTIR spectroscopy; high-resolution microscopy (HREM); scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS); Raman, photoluminescence, UV-Vis, and DRS spectroscopies; and by tensile tension tests. Results showed the successful formation and impregnation of NPs on the cotton fabric, with negligible leaching of NPs after several washing cycles. The photocatalytic activity of supported NPs was assessed by the degradation of methyl blue dye (MB) under solar and UV irradiation revealing improved photocatalytic activity of the Ag-TiO2/cotton composites due to a synergy of both Ag and TiO2 nanoparticles. This behavior is attributed to a diminished electron-hole recombination effect in the Ag-TiO2/cotton samples. The biocide activity of these composites on the growth inhibition of Staphylococcus aureus (Gram+) and Escherichia coli (Gram-) was confirmed, revealing interesting possibilities for the utilization of the functionalized cotton fabric as protective cloth for medical applications.

Mechanistic Insight into the Internalization, Distribution, and Autophagy Process of Manganese Nanoparticles in Capsicum annuum L.: Evidence from Orthogonal Microscopic Analysis.

Orthogonal techniques were used to track manganese nanoparticles (MnNPs) in Capsicum annuum L. leaf tissue and cell compartments and subsequently to explain the mechanism of uptake, translocation, and cellular interaction. C. annuum L was cultivated and foliarly exposed to MnNPs (100 mg/L, 50 mL/per leaf) before analysis by using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) as well as dark-field hyperspectral and two-photon microscopy. We visualized the internalization of MnNP aggregates from the leaf surface and observed particle accumulation in the leaf cuticle and epidermis as well as spongy mesophyll and guard cells. These techniques enabled a description of how MnNPs cross different plant tissues as well as selectively accumulate and translocate in specific cells. We also imaged abundant fluorescent vesicles and vacuoles containing MnNPs, indicating likely induction of autophagy processes in C. annuum L., which is the bio-response upon storing or transforming the particles. These findings highlight the importance of utilizing orthogonal techniques to characterize nanoscale material fate and distribution with complex biological matrices and demonstrate that such an approach offers a significant mechanistic understanding that can inform both risk assessment and efforts aimed at applying nanotechnology to agriculture.

The semiconductor properties and tin segregation mechanism in the passive film formed on the electrodeposited Ni-Sn coatings

The nanocrystalline Ni-Sn coatings (average grain size 15.78 nm) formed of relatively ordered circular particles covering the entire surface characterized with nodule-like endings were successfully electrodeposited using pulse electrodeposition technique. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD) were used to analyse the film microstructure. The corrosion resistance and semiconducting properties of Ni-Sn coatings were investigated in borate buffer solution. The EIS measurements showed that Ni-Sn alloys developed, in the passive zone, a good corrosion resistance as demonstrated by a thin film thickness, the low capacitance value, high polarization resistance, and the high value of electric field strength. Mott-Schottky analysis showed that the passive film formed on Ni-Sn coatings presents an p-n heterojunction characteristic indicating that the charge carrier densities are composed of cation (NA) and anion (ND) vacancies. The high density of point defects (NA + ND ∼ 1021cm−3) induces a high electronic conductivity in the Ni-Sn coatings passive film. The XPS analysis showed that the passive film formed on Ni-Sn alloys is composed of NiO, Ni(OH)2, NiOOH, SnO, and SnO2 species and an enrichment of Sn in the passive film. The mechanisms of passive film growth and Sn segregation in the Ni-Sn passive film are suggested in conjunction with the Point Defect Model (PDM). The good corrosion resistance and high electronic conductivity achieved in this work suggest that Ni-Sn Coating is a good candidate for water electrolysis applications.