Elemental Mapping Techniques Research Articles

Graphene Oxide and Graphene Oxide-TiO₂ Nanocomposites: Synthesis, Characterization, and Rhodamine B Photodegradation Investigation.

In this study, graphene oxide (GO) sheets were successfully synthesized using two routes: conventional Hummers' (HGO) and modified Hummers' (or Marcano's) (MGO) methods. GO sheets were then assembled with TiO₂ nanoparticles to form nanocomposites (i.e., HGO-TO and MGO-TO). The properties of HGO and MGO and their nanocomposites with TiO₂ were evaluated by Fouriertransform infrared (FTIR), Raman, ultraviolet-visible (UV-Vis) adsorption, and diffuse reflectance (DRS) spectroscopies, X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The specific surface area, pore volume, and pore size of MGO, determined by Brunauer-Emmett-Teller (BET) equation, were 565 m²g-1, 376 cm³ g-1, and 30 nm, respectively; all of these parameters decreased after MGO was combined with TiO₂. In addition, compared with HGO, MGO possessed higher oxidation level and more stable bonding with TiO₂ nanoparticles. The morphology of HGO and MGO, which were characterized by scanning electron (SEM) and transmission electron microscopies (TEM), together with energy-dispersive X-ray (EDX) spectroscopy and elemental mapping technique, was determined to consist of TiO₂ nanoparticle-assembled GO sheets. All GO-TiO₂ nanocomposite samples exhibited a very high activity (˜100%) toward rhodamine B (RhB) dye photodegradation under natural sunlight exposure within 60 min. The obtained results for the GO-TiO₂ nanocomposite showed the potential of its application in wastewater purification and other environmental aspects.

Highly sensitive non-enzymatic electrochemical glucose sensor based on dumbbell-shaped double-shelled hollow nanoporous CuO/ZnO microstructures

A high-performance non-enzymatic glucose sensor based on hybrid metal-oxides is proposed. Dumbbell-shaped double-shelled hollow nanoporous CuO/ZnO microstructures (CuO/ZnO-DSDSHNM) were prepared via the hydrothermal method using pluronic F-127 as a surfactant. This structure is studied by various physicochemical characterizations such as scanning electron microscopy, X-ray diffraction spectroscopy, inductively coupled plasma atomic emission spectroscopy, elemental mapping techniques, X-ray photoelectron spectroscopy, and transmission electron microscopy. This unique CuO/ZnO-DSDSHNM provides both a large surface area and an easy penetrable structure facilitating improved electrochemical reactivity toward glucose oxidation. The prepared CuO/ZnO-DSDSHNM was used over the glassy carbon electrode (GCE) as the active material for glucose detection and then coated by Nafion to provide the proposed Nafion/CuO/ZnO-DSDSHNM/GCE. The fabricated glucose sensor exhibits an extremely wide dynamic range from 500 nM to 100 mM, a sensitivity of 1536.80 µA mM−1 cm−2, a low limit of detection of 357.5 nM, and a short response time of 1.60 s. The proposed sensor also showed long-term stability, good reproducibility, favorable repeatability, excellent selectivity, and satisfactory applicability for glucose detection in human serum samples. The achieved high-performance glucose sensing based on Nafion/CuO/ZnO-DSDSHNM/GCE shows that both the material synthesis and the sensor fabrication methods have been promising and they can be used in future researches.

The Study of Surface Roughness and Tool Wear Analysis in Turning of Aluminum Using Different Advanced Cutting Tools

As the aviation along with automobile industrial units require high finish with precise surface, so the machining process tends to focus about the machined part surface integrity having lower cost with less tool wear. Aluminium and Al-alloys are the most suitable ones due to their peculiar properties for these requirements.. Here the dry turning of pure aluminium has been attempted using advanced tools like uncoated WC, WC + TiN, WC + Ti(C,N) +Al2O3 and PCD by using speed range from 400 to 700 m/min along with variation in feed rate. The highly precised Surtonic S-128 roughness tester was used to measure surface roughness while SEM (Scanning Electron Microscope) was utilised to observe chip shear band formation and tool wear. The Elemental mapping technique was used to analyse adhesion. The different results show that PCD tools are more suitable than other coated tools for the machining of Al.

Determination of halogenated hydrocarbons in urine samples using a needle trap device packed with Ni/Zn-BTC bi-MMOF via the dynamic headspace method.

In this study, a nickel/zinc–BTC bi-metallic metal–organic framework (bi-MMOF) was employed as a new and efficient adsorbent in a needle trap device (NTD) for headspace (HS) sampling, extraction and analysis of halogenated hydrocarbons (trichloroethylene, tetrachloroethylene, chloroform, and tetrachloroethylene) from spiked and real urine samples. Characterization of the prepared adsorbent was accomplished by FT-IR, PXRD, EDX, elemental mapping, and FE-SEM techniques. According to experimental results, the optimal temperature and extraction time, salt content, temperature and desorption time of the response surface methodology (RSM) and Box–Behnken design (BBD) were determined to be 56 °C and 30 min, 5.5%, 350 °C and 8 min for the studied halogenated hydrocarbons, respectively. The calculated values of detection limit and quantitation limit parameters were in the range of 1.02–1.10 and 2.01–2.4.0 ng L−1, respectively. Moreover, intermediate precision and repeatability of the method were in the range of 4.90–8.20% and 1.50–4.80%, respectively. The recovery percentages of analytes were obtained to be in the range of 95.0–97.0% 10 days after the sampling and storage at 4 °C. This study showed that the proposed HS-NTD:Ni/Zn–BTC method coupled with a GC-FID can be employed as a simple, fast, and sensitive procedure for non-metabolized halogenated hydrocarbons from urine samples in biological monitoring.

An Eco-friendly nanocatalyst for removal of some poisonous environmental pollutions and statistically evaluation of its performance

Through an ecofriendly, economic and one pot method, the TiO2@Fe3O4@Quartz nanocomposite (NCs) was fabricated using the antioxidant potential of the Allium tricoccum extract and quartz as a natural geosubstrate (G.S). Also, high performance liquid chromatography (HPLC) analysis of the plant and evaluation of its total phenolic content (TPC) revealed its high potential to biosynthesis of the catalyst. The ecofriendly catalyst structurally elucidated using the SEM, EDS, Elemental mapping, XRD and FT-IR techniques. Moreover, the catalytic potential of TiO2@Fe3O4@Quartz NCs was studied for removal of some hazardous materials including polycyclic aromatic hydrocarbons (PAHs), azo dyes and the reduction of dangerous hexavalent Cr(VI) and 2,4-dinitrophenyl hydrazine (2,4-DNPH) at ambient conditions in which analysis of the surface of nanostructure using GC-Mass demonstrated a significant removal of poisonous PAHs from the crude oil sample. Besides experimental investigating of the catalyst performance, the statistical analysis was used to evaluation the optimal amount of the catalyst for each reaction. Furthermore, beside the presentation of all reaction mechanisms, the reusability for TiO2@Fe3O4@Quartz NCs revealed its recoverability for consequent times with no meaningful loss of its activity.

Efficient biogenesis of Cu2O nanoparticles using extract of Camellia sinensis leaf: Evaluation of catalytic, cytotoxicity, antioxidant, and anti-human ovarian cancer properties

At the moment, metallic nanoparticles especially copper nanoparticles are administrated for the cure of different disorders, such as tumor and cancer. In recent years, many chemotherapeutic supplements have been formulated by copper nanoparticles. In the present study, copper nanoparticles were prepared and synthesized in aqueous medium using Camellia sinensis leaf extract. The as-prepared Cu2O nanoparticles was thoroughly characterized using XRD, FT-IR, FESEM, EDX, TEM and X-ray elemental mapping techniques. The as-synthesized Cu2O/C. sinensis NPs applied as novel nanocatalyst for the synthesis of annulated fused pyrano[2,3-d]pyrimidinones via a one-pot, three-component condensation of a barbituric acid, aromatic aldehydes, and malonitrile or ethylcyanoacetate under mild condition at 25 °C. Main properties of this facile method are the involves an easy work-up procedure, avoidance of hazardous or polluting chemicals, significant yields under mild conditions, and one-pot reaction. We assessed the anti-human ovarian cancer potentials of these nanoparticles against Caov-3, SW-626, and SK-OV-3 cell lines. For investigating the antioxidant activities of CuCl2⋅2H2O, C. sinensis, and copper nanoparticles, the DPPH free radical test was used. For the determining of anti-human ovarian cancer properties of CuCl2⋅2H2O, Camellia sinensis leaf aqueous extract, copper nanoparticles, and Carboplatin (Standard positive control), MTT assay was used on normal (HUVECs) and human ovarian cancer (Caov-3, SW-626, and SK-OV-3) cell lines. Copper nanoparticles had high cell death and anti-human ovarian cancer properties against Caov-3, SW-626, and SK-OV-3 cell lines. Among the above cell lines, the best result was gained in the cell line of SW-626. According to the above findings, it looks copper nanoparticles green-synthesized by Camellia sinensis leaf aqueous extract have the potential to be used as a chemotherapeutic material for human ovarian cancers.

Synthesis of Imidazolium‐Based Ionic Liquid on Modified Magnetic Nanoparticles for Application in One‐Pot Synthesis of Trisubstituted Imidazoles

AbstractThe core‐shell of Fe3O4@SiO2 modified by epichlorohydrin and 1‐methyl‐imidazole (Fe3O4@SiO2‐EPIM), a new green recyclable nanocatalyst, was designed and prepared. This nanocatalyst was characterized using fourier‐transform infrared spectroscopy (FT‐IR), field‐emission scanning electron microscopy (FESEM), energy‐dispersive X‐ray spectroscopy (EDS), elemental mapping technique, transmission electron microscopy (TEM), X‐ray diffraction (XRD) techniques, thermal gravimetric analysis (TGA), N2 adsorption‐desorption by Brunauer‐Emmet‐Teller (BET) and vibrating sample magnetometer (VSM). The catalytic activity of Fe3O4@SiO2‐EPIM was assessed for synthesis of trisubstituted imidazoles via one‐pot condensation reactions of benzil, aldehyde and ammonium acetate under the optimal reaction condition (PEG 200, 100 °C, 0.02 g catalyst). This nanocatalyst displayed remarkable superiorities, such as environmental friendliness, shorter reaction time, excellent yields, reusability of the catalyst and simple workup procedure.

Improved electrochemical performance of SiO2-coated Li-rich layered oxides-Li1.2Ni0.13Mn0.54Co0.13O2

Lithium-rich layered oxides (LLOs) such as Li1.2Ni0.13Mn0.54Co0.13O2 are suitable cathode materials for future lithium-ion batteries (LIBs). Despite some salient advantages, like low cost, ease of fabrication, high capacity, and higher operating voltage, these materials suffer from low cyclic stability and poor capacity retention. Several different techniques have been proposed to address the limitations associated with LLOs. Herein, we report the surface modification of Li1.2Ni0.13Mn0.54Co0.13O2 by utilizing cheap and readily available silica (SiO2) to improve its electrochemical performance. Towards this direction, Li1.2Ni0.13Mn0.54Co0.13O2 was synthesized utilizing a sol–gel process and coated with SiO2 (SiO2 = 1.0 wt%, 1.5 wt%, and 2.0 wt%) employing dry ball milling technique. XRD, SEM, TEM, elemental mapping and XPS characterization techniques confirm the formation of phase pure materials and presence of SiO2 coating layer on the surface of Li1.2Ni0.13Mn0.54Co0.13O2 particles. The electrochemical measurements indicate that the SiO2-coated Li1.2Ni0.13Mn0.54Co0.13O2 materials show improved electrochemical performance in terms of capacity retention and cyclability when compared to the uncoated material. This improvement in electrochemical performance can be related to the prevention of electrolyte decomposition when in direct contact with the surface of charged Li1.2Ni0.13Mn0.54Co0.13O2 cathode material. The SiO2 coating thus prevents the unwanted side reactions between cathode material and the electrolyte. 1.0 wt% SiO2-coated Li1.2Ni0.13Mn0.54Co0.13O2shows the best electrochemical performance in terms of rate capability and capacity retention.

Trichloroethylene degradation by PVA-coated calcium peroxide nanoparticles in Fe(II)-based catalytic systems: enhanced performance by citric acid and nanoscale iron sulfide.

In this study, the enhanced trichloroethylene (TCE) degradation performance was investigated by polyvinyl alcohol coated calcium peroxide nanoparticles (PVA@nCP) as an oxidant in Fe(II)-based catalytic systems. The nanoscale iron sulfide (nFeS), having an average particle size of 115.4 nm, was synthesized in the laboratory and characterized by SEM, TEM, HR-TEM along with EDS elemental mapping, XRD, FTIR, ICP-OES, and XPS techniques. In only ferrous iron catalyzed system (PVA@nCP/Fe(II)), TCE degradation was recorded at 58.9% in 6 h. In comparison, this value was increased to 97.5% or 99.7% with the addition of citric acid (CA) or nFeS in PVA@nCP/Fe(II) system, respectively. A comparative study was performed with optimum usages of chemical reagents in both PVA@nCP/Fe(II)/CA and PVA@nCP/Fe(II)/nFeS systems. Further, the probe compounds tests and electron paramagnetic resonance (EPR) analysis confirmed the generation of reactive oxygen species. The scavenging experiments elucidated the dominant role of HO• to TCE degradation, particularly in PVA@nCP/Fe(II)/nFeS system. Both CA and nFeS strengthened PVA@nCP/Fe(II) system, but displayed completely different mechanisms in the enhancement of active radicals generation; hence, their different contribution to TCE degradation. The acidic environment was favorable for TCE degradation, and a high concentration of HCO3- inhibited TCE removal in both systems. Conclusively, compared to PVA@nCP/Fe(II)/nFeS system, PVA@nCP/Fe(II)/CA system resulted in encouraging TCE degradation outcomes in actual groundwater, showing great potential for prolonged benefits in the remediation of TCE polluted groundwater. Graphical abstract.

Temperature-dependent interfacial behaviour of Au@SiO2 core shell nanoparticles on Si3N4 support film

Structural, chemical, and thermodynamic behaviours of metallic nanostructures surrounded by a variety of ceramic/refractory materials play a crucial role in their high-temperature applications. In this work, we report the effect of high-temperature annealing on a system of Au@SiO2 core-shell nanoparticles dispersed on Si3N4 grids. The thermal degradation of the Au–SiO2–Si3N4 system has been explained using minute compositional changes at different interfaces involving Au–SiO2, SiO2–Si3N4 and Au–Si3N4. High Angle Annular Dark Field Imaging coupled with Energy Dispersive X-ray Spectroscopy elemental mapping technique has been used for the same. Possible reactions among SiO2 and Si3N4 substrate with the aid of Au at high temperature leading to thermal decomposition of the system have been explained using High-Resolution Transmission Electron Microscopy and Selected Area Electron Diffraction analysis.

High Performance Magnetically Separable G‐C3N4/γ‐Fe2O3/TiO2 Nanocomposite with Boosted Photocatalytic Capability towards the Cefixime Trihydrate Degradation under Visible‐Light

AbstractA magnetically separable g‐C3N4/γ‐Fe2O3/TiO2 nanocomposite is synthesized as an intensely effectual visible‐light‐driven photocatalyst. It is fully characterized by FT‐IR, XPS, XRD, VSM, DRS, SEM, TEM, BET, EDS, and elemental mapping techniques. Based on the Tauc plot of (αhν)2 vs. hυ, the value of band gap energy for g‐C3N4/γ‐Fe2O3/TiO2 is estimated to be 2.6 eV, which proves the high capability of the catalyst to enhance the photoinduced electron‐holes separation and improves its visible‐light photocatalytic performance. The high photocatalytic activity of this catalyst towards the cefixime trihydrate (CEF) degradation, under visible‐light radiation can be ascribed to the synergistic optical effects between g‐C3N4, γ‐Fe2O3, and TiO2. Using central composite design (CCD) based on response surface methodology (RSM), the maximum degradation efficiency of about 98 % was obtained at the optimal conditions comprising the CEF amount of 20 mg/L, photocatalyst value of 0.04 g/L, irradiation intensity of 9 W/m2, and pH of 5.5, at 90 min. Utilizing an innocuous visible‐light source, almost complete mineralization of CEF (based on TOC analysis), using a very low amount of photocatalyst, applying air as the oxidant, and convenient magnetic separation of the catalyst from the reaction media and its ease of recycling for at least seven consecutive runs are the major highlights of this protocol.

Bi-functional catalytic performance of silver manganite/polypyrrole nanocomposite for electrocatalytic sensing and photocatalytic degradation

Detection and degradation of perilous polluting materials are important in the study of health and environmental issues. Nowadays, researches are on the path to invent dual functional materials. On that basis, we have designed a simple one-pot synthesis of silver manganite incorporated polypyrrole polymer nanocomposite (AMNPY). The physicochemical, morphological, electrical and optical properties of as-synthesized nanocomposites were characterized using PXRD, XPS, FESEM, TEM, EDX, Elemental Mapping, UV-DRS, FTIR, CV, DPV and EIS techniques. Incorporation of polypyrrole (PPy) with silver manganite (AMN) was initially studied using FTIR spectral data. The microscopic images have revealed the particles into nano range and show better correlation with the average particle size, which was calculated from PXRD analysis. Furthermore, the photocatalytic and electrocatalytic potential of the as-synthesized nanocomposite were evaluated. AMNPY exhibits excellent activity in the photocatalytic degradation of methyl orange dye (99.6 %) and chloramphenicol drug (98.9 %) within 30 min. The photocatalyst was highly recyclable which was evaluated and confirmed up to 5 cycles. Further, on the evaluation of electrochemical sensing activity of AMNPY modified screen printed carbon electrode (AMNPY/SPCE) demonstrated an excellent sensing in the detection of antibiotic drug furazolidone. The AMNPY/SPCE exhibited two wide linear response ranges (0.1 μM to 10 μM; 18 μM to 906 μM) along with lower detection limit of about 3 nM. In addition to this, the potential sensor proved an outstanding sensitivity of 6.95 μA μM−1 cm-2 and prominent selectivity even in the presence of biomolecules, metal ions and strong interfering derivatives.

Silylated-montmorillonite as co-adsorbent of chitosan composites for methylene blue dye removal in aqueous solution

Industrialization plays important role in the economy of developing countries, including increasing community welfare. However, the presence of poorly industries waste disposal system has negative impact to the environment. Therefore, it is necessary to overcome this problem with low-cost technology, called adsorption. In this research, silylated-montmorillonite (sMMt) has been successfully prepared as supporting material for adsorption of methylene blue by chitosan. The sMMt was characterized by FTIR, XRD, and elemental mapping techniques. The chitosan/sMMt composites were prepared through dissolution-precipitation method and produced rod-like morphology as observed by SEM. The adsorption process was carried out in a batch method by studying the pH and the adsorption contact time. The adsorption kinetic mechanism of the chitosan/sMMt nanocomposite followed pseudo-second order rather than Lagergren model indicating chemisorption predominant. The addition of silylated-montmorillonite into chitosan enhanced the methylene blue dye removal performance, which evidenced by improving Qe values by 10% compared to chitosan.

Greener pathway toward the synthesis of lichen-based ZnO@TiO2@SiO2 and Fe3O4@SiO2 nanocomposites and investigation of their biological activities.

A green way is introduced to biosynthesis of ZnO@TiO2@SiO2 and Fe3O4@SiO2 nanocomposites using the bioactive potential of Lecanora muralis (LM) lichen. UV‐Vis spectroscopy and GC–Mass analysis of the lichen show the presence of various bioactive constituents inside the lichen aqueous extract. The XRD, SEM, EDS, and elemental mapping techniques revealed the well fabrication of biosynthesized nanostructures. Also, investigation of antibacterial and antifungal activities of nanostructures demonstrated that green synthesized nanostructures have a very good antibacterial ability against Staphylococcus aureus, Escherichia coli, Pseudomonas spp. and Candida spp. pathogenic bacteria, and fungi but no antifungal activity toward the Aspergillus flavus, Aspergillus niger, and Aspergillus terrus fungi species.

Alkali metal-incorporated spinel oxide nanofibers enable high performance detection of formaldehyde at ppb level

Sensing material with high sensitivity, excellent selectivity and ultra-low detection limit is crucial for monitoring formaldehyde, which is a kind of hazardous gas to human health at very low concentration. Some one-dimensional semiconductor metal oxides show acceptable responses towards formaldehyde. However, the detection limit and selectivity of these sensors are still not satisfied, especially at ppb level. Herein, alkali metals (K, Na) doped CdGa2O4 nanofibers with excellent formaldehyde sensing performance are prepared by an electrospinning method. These nanofibers have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), electron paramagnetic resonance spectroscopy (EPR), elemental mapping and other techniques. As a result, the sensor based on 7.5 at.% K doped CdGa2O4 gives remarkably improved formaldehyde sensing properties compared with that of pristine CdGa2O4. The greatly increased sensitivity and selectivity should be attributed to the increased chemisorbed oxygen and the enhanced basicity caused by the additional alkali metal, respectively. All in all, the 7.5 at.% K doped CdGa2O4 is a good candidate for the rapid detecting formaldehyde at ppb level.

A glassy carbon electrode modified with tailored nanostructures of cobalt oxide for oxygen reduction reaction

Herein we report on various surface morphological characteristics of the synthesized cobalt oxide (Co3O4) nanostructures obtained by means of facile one-step hydrothermal method for oxygen reduction reaction (ORR). The synthesized nanostructures of Co3O4 were adequately characterized by field emission scanning electron microscopy (FESEM) fitted with Energy-dispersive X-ray spectroscopy (EDX) elemental mapping, X-ray diffraction (XRD) and Raman techniques. The electrochemical studies were carried out to analyse the performance of as-synthesized catalysts for ORR by cyclic voltammetry (CV), and chronoamperometric (CA) techniques. A higher electrocatalytic response was observed for Co3O4 nanocubes compared with all the other controlled electrodes by CV with a current density of 0.69 mA/cm2 at a potential value of −0.46 V. The as-synthesized material showed adequate tolerance against methanol observed by CV in the presence of 0.5 M methanol, and good stability when compared with commercial Pt/C catalyst using the CA technique.

Hydrothermal synthesis of C-doped K2Al2Ti6O16 as a visible light–activated photocatalyst in the degradation of organic dyes

Hydrothermally synthesized C-doped K2Al2Ti6O16 (C-KATO) is reported as a novel photocatalysts for methylene blue (MB) and methyl orange (MO) degradation under visible light irradiation. Glucose is used as a carbon source. The structural, morphological, and optical properties are investigated using powder XRD, FE-SEM/EDS elemental mapping, TEM/HR-TEM, FT-IR, UV-Vis DRS, and XPS techniques. C-KATO sample crystallized in the tetragonal lattice with space group I4/m. The bandgap energy of C-KATO is found to be 2.59 eV whereas the bandgap energy of the parent KATO is 3.58 eV. FE-SEM elemental mapping and XPS results of C-KATO reveal the presence of carbon in the KATO lattice. The photocatalytic activities of the KATO and C-KATO oxides are evaluated for MB and MO degradation under visible light irradiation, and the results have been compared with those attained over P25 Degussa. It shows higher activity in comparison to P25. The mechanistic dye degradation pathway is studied using radical scavengers during photoreaction.

Kinetic evaluation of dehydration in MxNa96-xLSX (M= Li+, Ca2+ and Ag+) zeolites and resulting effects on selective adsorption of N2 and O2

Abstract The purpose of this study is to evaluate the dehydration kinetics of MxNa96-x-LSX (M = Li+, Ca2+ and Ag+) zeolites and assess their potential for N2/O2 adsorption and selectivity using ideal adsorbed solution theory. In order to achieve our objective, MxNa96-x-LSX (M = Li+, Ca2+, and Ag+) zeolites were prepared via conventional ion exchange methods from Na-LSX zeolite. Meanwhile, their structural and textural properties were characterized by N2 adsorption-desorption, TG-DTG, ICP-OES, XRD, FT-IR, EDS, elemental mapping and SEM techniques. The kinetics (activation energy, pre-exponential factor, and most probable mechanism/model) of dehydration process were investigated via Kissinger, Flynn-Wall-Ozawa and Coats-Redfern methods. The results show a strong dependence on the choice of mechanism function, which can help in proposing the best relevant kinetic model. Moreover, the results further reveal that Li+ and Ca2+ ions (which are inexpensive) in Li-LSX and Ca-LSX fill the low-energy sites SI, SI′, SII, and SII′ first and then SIII and SIII′ sites. Li-LSX and Ca-LSX hold comparative advantages, which suggest that they would be the most promising adsorbents for air separation and pure oxygen production by pressure swing adsorption. However, Ag-LSX presents superior performance at relatively low pressures. Therefore, the quantitative evaluation of kinetic parameters of dehydration is necessary to provide the theoretical principles in understanding N2 and O2 adsorption phenomena.

Phosphotungstic acid supported on functionalized graphene oxide nanosheets (GO-SiC3-NH3-H2PW): Preparation, characterization, and first catalytic application in the synthesis of amidoalkyl naphthols

Grafting of 3-aminopropyltriethoxysilane (APTS) on graphene oxide (GO) nanosheets followed by reaction with phosphotungstic acid (H3PW12O40,denoted as H3PW) gave a new functionalized GO which was characterized using FT-IR, FESEM, EDX, EDX elemental mapping and ICP-OES techniques. The catalytic activity of this nanomaterial containing phosphotungstic counter-anion H2PW12O40¯ (H2PW) which was denoted as GO-SiC3-NH3-H2PW was probed in the synthesis of amidoalkyl naphthols through the one-pot, three-component reaction of β‐naphthol with various aromatic aldehydes and acetamide. The results showed a significant catalytic performance of the catalyst for this transformation in ethanol as solvent at reflux temperature, giving the corresponding products in high yields. In addition, the nanocatalyst could be easily recovered from the reaction mixture and reused many times with no significant loss of its catalytic activity.

A Review of ex vivo Elemental Mapping Methods to Directly Image Changes in the Homeostasis of Diffusible Ions (Na+, K+, Mg2 +, Ca2 +, Cl-) Within Brain Tissue.

Diffusible ions (Na+, K+, Mg2+, Ca2+, Cl–) are vital for healthy function of all cells, especially brain cells. Unfortunately, the diffusible nature of these ions renders them difficult to study with traditional microscopy in situ within ex vivo brain tissue sections. This mini-review examines the recent progress in the field, using direct elemental mapping techniques to study ion homeostasis during normal brain physiology and pathophysiology, through measurement of ion distribution and concentration in ex vivo brain tissue sections. The mini-review examines the advantages and limitations of specific techniques: proton induced X-ray emission (PIXE), X-ray fluorescence microscopy (XFM), secondary ion mass spectrometry (SIMS), laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and the sample preparation requirements to study diffusible ions with these methods.