X-ray Elemental Mapping Research Articles

N-doped carbon nanoflakes coordinate with amorphous Fe to activate ozone for degradation of p-nitrophenol

Due to their high catalytic performance, metal nitrogen-doped carbon materials are widely used in the field of environmental restoration of polluted water but there is limited research on metal nitrogen doped carbon composite materials as ozone catalysts. Herein, we report the preparation of amorphous iron-coordinated nitrogen-doped carbon nanosheets as a catalyst for ozone by the coordination of Fe-metal ions at the end of phenol chain in the lignin network. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (Raman), powder X-ray diffraction (XRD) and element mapping were used to characterize the Fe/D-NC composite material and investigate its morphology and composition. Highly uniform distribution of iron species was found through characterization. By exploring the degradation performance of composite materials of Fe/D-NC-T (700，800，900 ℃) prepared at different temperatures, it was found that the optimal Fe/D-NC-800 could effectively degrade p-nitrophenol (PNP) within 30 min. Quenching experiments and ESR analysis showed that both free and non-free radicals (•OH, O2•− and 1O2) and intrinsic Lewis acid sites (LAS) of the composite material Fe/D-NC-800 were involved and responsible for the degradation of PNP. This work not only offers new platforms for catalytic ozonation and may drive the development of metal-lignin-based catalytic ozonation for effective water treatment but also opens new avenues toward lignin valorization and biomass economy.

Exploring the optical and biological aspects of sodium- doped CuO nanoparticles

In this article, we present a novel coprecipitation technique for synthesizing pure and sodium-doped CuO (Cu1-xNaxO) nano powders with different sodium concentrations (x = 0, 0.01, 0.02, 0.04, 0.06, 0.08, and 0.10). The structural properties of the samples were analysed using powder X-ray diffraction (PXRD), which revealed an average crystallite size of 12.48–10.50 nm. The bonding nature of the Cu1-xNaxO samples was described by Fourier transform infrared (FTIR) spectroscopy. The UV–Visible spectroscopic analysis showed a band gap energy of 1.240–1.456 eV and a refractive index that decreased with an increase in Na doping concentration. Field emission scanning electron microscopy images revealed the spherical, flower-shaped, and flake-like morphologies of the nanoparticles, which had sizes ranging from 42.45 ± 5.49–33.98 ± 4.32 nm. Energy-dispersive X-ray spectroscopy and elemental mapping were used to confirm the purity of the samples and the presence of Cu, O, and Na elements in the Cu1-xNaxO samples. High-resolution transmission electron microscopy photomicrographs confirmed that the samples were polycrystalline and the nanoparticles exhibited nucleation with lattice spacing, as shown by selected-area electron diffraction patterns. Furthermore, the Cu1-xNaxO nano powders exhibited efficient antibacterial and antifungal activities. The antibacterial activity was tested against major bacterial strains, and the highest inhibition zones were observed to be 13.67 ± 1.11 mm (x = 0.06), 10.67 ± 0.94 mm (x = 0.10), 15 ± 1.11 mm (x = 0.10), and 9.25 ± 0.25 mm (x = 0.06) for P. aeruginosa, B. subtilis, S. aureus, and K. pneumonia, respectively. In addition, the antifungal activity of the Na-doped CuO nano powders was found to be enhanced against polymorphic fungus C. albicans and filamentous fungus A. niger with dopant concentration. These results suggest that Na-doped CuO NPs have potential applications in formulating new antifungal drugs and treating various life-threatening bacterial infections.

Gold nanoparticles embedded Fe-BTC (AuNPs@Fe-BTC) metal-organic framework as a fluorescence sensor for the selective detection of As(III) in contaminated waters

In this article, a new off-mode fluorescent platform based on the metal-organic framework (MOF) is introduced as a highly selective and rapid chemical sensor for the detection of As(III) in water and wastewater samples. A typical Fe-BTC (BTC = 1,3,5-benzenetricarboxylate or trimesic acid) MOF was used as a porous template for loading gold nanoparticles (AuNPs@Fe-BTC MOF). The physicochemical properties of AuNPs@Fe-BTC MOF were characterized by Fourier-transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EAX), element mapping (MAP) and X-ray diffraction (XRD) analysis. This sensing method for As(III) ions is based on the fact that the fluorescence intensity of AuNPs@Fe-BTC MOF sensor decreases in proportion to the increase in As(III) concentration. The main effective factors on the performance of the sensor signal such as MOF dosage, sonication time, pH and reaction time were optimized. Under optimized conditions, the calibration graph was linear in the concentration range of 0.5–380 ng mL−1 of As(III) and the limit of detection was 0.2 ng mL−1. The proposed method was successfully validated by addition/recovery experiments by the determination of As(III) in four river water and two wastewater effluent samples.

Enhancing asymmetric supercapacitor performance with NiCo2O4–NiO hybrid electrode fabrication

Spinel metal oxide with an extra crystalline phase is an active way to enhance the performance of the supercapacitor. Herein, a facile hydrothermal approach has been established for synthesizing nanocrystalline NiCo2O4 with an extra NiO phase material as the potential electrode for a supercapacitor. XRD analysis is executed to expose the crystalline environment and found to be dual phases ie. NiO and NiCo2O4. Further, the chemical environment of these phases is identified in FTIR, EDS, X-ray photoelectron spectroscopy, elemental mapping, and Raman analysis. The morphological analysis (SEM) of the material showed that the formation of tiny particulates aggregates become uniform in size, which consists of a nearly spherical structure. NiCo2O4–NiO showed a remarkable electrochemical performance in a 2 M potassium hydroxide. The maximum capacitance was achieved as 866 F/g at a sweep rate of 5 m V/s, which is quite higher than the normal pristine NiCo2O4. The material delivered a capacity retention of 85% over 5000 cycles. This high performance was attributed to the NiO phase in NiCo2O4 material inducing an additional charge at the boundary, prominent to synergistic effect and rapid electron and ion passage. Hence, overall, the superior performance with extra NiO phase could be beneficial for developing spinel metal oxide electrodes for battery-type supercapacitor applications.

Three-Dimensional Assemblages of Metal Silicate for Catalytic CO2 Conversion to Methanol and Adsorptive Pollutant Removal

Morphological transformation was performed on Stöber silica nanospheres (ca. 270 nm in diameter) and transmuted into either ZnSiO (zinc silicate) nanoflowers or MgSiO (magnesium silicate) nanoflowers (600–800 nm in diameter) through a facile hydrothermal process. The zinc silicate materials were then chosen for incipient wetness impregnation to imbue them with different levels of Cu and Zn doping due to the well-established elemental synergy of Cu and Zn toward methanol synthesis via CO2 hydrogenation. Characterization results concur that zinc silicate nanoflowers loaded with copper(II) oxide were formed after incipient wetness impregnation. Three as-synthesized catalyst candidates with different copper loadings were then evaluated for CO2 hydrogenation and compared against an industrial catalyst. After the reaction, high-resolution transmission electron microscopy (HRTEM) with energy-dispersive X-ray (EDX) elemental mapping reveal that petite Cu nanoparticles formed on the petals of the impregnated zinc silicate nanoflowers. Experimental results show that all catalyst materials have an exceptional high methanol selectivity, with overall performance exceeding that of the industrial catalyst at per Cu basis. Both ZnSiO and MgSiO were also evaluated through a simple methylene blue adsorption test. Hence, through deliberate morphological control and chemical transformation, superficially inert Stöber silica nanospheres were functionalized into transition- and earth-alkaline metal silicates, which exhibit catalytic and adsorptive properties with a nanoflower morphology that prevents interstacking of nanosheets.

Efficiency of the green formulated iron nanoparticles as a new tool in lung cancer therapy

In the recent study, we described a novel iron nanoparticles green-mediated by arabic coffee as a novel anticancer agent (FeNPs). The recent nanoparticles were analyzed by Fourier transformed infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), elemental mapping, X-ray diffraction (XRD) and ultraviolet–visible spectroscopy (UV–Vis). The iron nanoparticles showed the best antioxidant activities against DPPH. The IC50 of iron nanoparticles and BHT against DPPH free radicals were 165 and 62 µg/mL, respectively. In the oncological part of the recent study, the treated cells with iron nanoparticles were assessed by MTT assay for 48 h about the cytotoxicity and anticancer properties on normal (HUVEC) and lung cancer cell lines. The IC50 of iron nanoparticles were 273, 216, and 250 µg/mL against HT144, SKMEL2, and WM266-4 cell lines, respectively. The viability of malignant cell lines reduced dose-dependently in the presence of iron nanoparticles.

Dual color luminescence of Mn2+ doped lead-free Cs3Cu2I5 perovskite phosphors and their LED solid-state lighting and anti-counterfeiting applications

Cs3Cu2I5 have recently attracted far-flung and fervency interests with the characters of low cost, high photoluminescence quantum yield, green and non-toxicity. In addition, continuous tuning of the luminescence properties could be realized in Cs3Cu2I5, which would benefit its optical applications. Herein, Mn2+ is chosen as the luminescent center into Cs3Cu2I5 through solid-state ball milling method. Its structure and photoluminescence properties have been studied by various characterization methods such as X-ray powder diffractions, fluorescence spectroscopy, and element mapping. These results showed that Mn2+ doping into Cs3Cu2I5 makes little change on the crystal structure of Cs3Cu2I5. The copper ions and manganese ions exist stably in the form of Cu+ and Mn2+, respectively. After Mn2+ doping, a new emission peak appears at 560 nm except for the intrinsic blue emission of Cs3Cu2I5, thus realizing dual color luminescence. This material also exhibits excellent thermal stability, making it suitable for solid-state lighting and anti-counterfeiting applications.

High-Resolution Analysis of Fe–Mn Oxyhydroxide in Ferromanganese Nodules from the Northwestern Pacific Ocean and Insights on Element Mobility

Due to the multiple and poorly-crystallized phases in ferromanganese (Fe–Mn) nodules, research on the variability of micro-layers in nodules is limited and the accumulation of various elements with the growth of micro-layers have not been well documented. To address this gap, we examined the spatial distributions of elements in cross-sections of nodules from the Northwestern Pacific Ocean using in-situ electron microprobe analyses coupled with backscattered electron imaging and high-resolution X-ray elemental intensity mapping. Results suggest their significant selective enrichment of metal elements is similar to that of typical hydrogenetic nodules and diagenetic nodules. Moreover, WMn+Fe of Fe–Mn oxyhydroxide is equal to 50% after normalization and Co and Ni show positive relationships with Mn/Fe ratio, suggesting Fe oxyhydroxide would serve as a diluter at exposed surface during nodule growth. In suboxic conditions, Mn, Ni, and Co start to release, and the remaining Fe oxyhydroxide may react with the surrounding sediment to form Si-rich layers. Our studies reveal the diverse growth processes and show a much larger chemical heterogeneity of individual layers, which extend the models about the mechanisms of chemical precipitation and environmental conditions that existed during nodule growth.

One-Pot Synthesis of Cyclomatrix-Type Polyphosphazene Microspheres and Their High Thermal Stability.

Highly cross-linked inorganic and organic hybrid cyclomatrix-polyphosphazenes microspheres (C-PPZs) have been successfully synthesized by a one-pot polymerization technique between hexachlorocyclotriphosphazene and p-phenylenediamine in the presence of triethylamine (TEA), and they were used for enhancing the flame retardancy of epoxy resins (EPs). A thermoset EP was prepared by incorporating different percentages (2, 5, and 10%) of C-PPZs into diglycidyl ether of bisphenol A (DGEBA). The results reveal that the size and morphology of the microspheres can be tuned by varying the synthesis temperature. The average size of C-CPPZs gradually increased from 3.1, 4.9, to 7.8 μm as the temperature was increased from 100, 120, to 200 °C, respectively. The thermogravimetric analysis showed that the C-CPPZ microspheres have good thermal stability up to 900 °C with about ∼10 wt % mass loss for C-CPPZs formed at 200 °C compared to ∼30 wt % mass loss for those obtained at 100 and 120 °C. The 10% loss at 900 °C is much lower than the previous research concerning the thermal stability of cyclophosphazene, in which more weight losses were observed at lower temperatures. The resulting C-CPPZ microspheres were characterized by spectroscopic and imaging techniques including Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, and X-ray photoelectron spectroscopy.

Comprehensive analysis on the effect of ionic size and size disorder parameter in high entropy stabilized ferromagnetic manganite perovskite

A series of high entropy manganites, $(5{A}_{0.2}){\mathrm{MnO}}_{3}$, were prepared with varying the average ionic radius, $\ensuremath{\langle}{r}_{A}\ensuremath{\rangle}$, and cationic size disorder, ${\ensuremath{\sigma}}^{2}$, on the $A$ site. All the samples were synthesized using the citrate sol-gel method. In all the compounds, the manganese valence was kept unaltered with reference to the conventional manganite ${\mathrm{La}}_{0.6}{\mathrm{Sr}}_{0.4}{\mathrm{MnO}}_{3}$, which is ferromagnetic with ${T}_{C}\ensuremath{\sim}365$ K. The ratio of manganese valance is found to be unaltered as confirmed using x-ray photoelectron studies. The samples were characterized by powder x-ray diffraction, field-emission scanning electron microscopy (FE-SEM), energy dispersive x-ray analysis, elemental mapping, and magnetization measurements. These high entropy oxides show the variation in Curie temperature over a wide range from 85 to 273 K depending on the average $A$-site ionic radius, $\ensuremath{\langle}{r}_{A}\ensuremath{\rangle}$. A drastic drop down in the ferromagnetic transition temperature of ${T}_{C}=365$ K for ${\mathrm{La}}_{0.6}{\mathrm{Sr}}_{0.4}{\mathrm{MnO}}_{3}$ with $\ensuremath{\langle}{r}_{A}\ensuremath{\rangle}=1.2536\phantom{\rule{0.16em}{0ex}}\AA{}$ to ${T}_{C}=137\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ for (${\mathrm{La}}_{0.2}{\mathrm{Nd}}_{0.2}{\mathrm{Gd}}_{0.2}{\mathrm{Sr}}_{0.2}{\mathrm{Ba}}_{0.2}$)${\mathrm{MnO}}_{3}$ of comparable $\ensuremath{\langle}{r}_{A}\ensuremath{\rangle}=1.2532\phantom{\rule{0.16em}{0ex}}\AA{}$ can be attributed to the high entropy and/or cationic size disorder effect. The variation of ${T}_{C}$ with $\ensuremath{\langle}{r}_{A}\ensuremath{\rangle}$ for the whole series of high entropy manganites does not follow the expected linear behavior; rather, it follows opposite traces of the variation in ${\ensuremath{\sigma}}^{2}$ with $\ensuremath{\langle}{r}_{A}\ensuremath{\rangle}$. However, ${T}_{C}$ shows almost linear behavior with ${\ensuremath{\sigma}}^{2}$ except for the sample with lowest $\ensuremath{\langle}{r}_{A}\ensuremath{\rangle}$. This result suggests that the local cationic disordering is more important than the average cationic size in ferromagnetic high entropy manganites. Unlike the conventional system in these high entropy oxides, the ferromagnetic state is not suppressed; only the length scale of the double exchange mediated long-range ferromagnetic interaction is transformed to localized ferromagnetic clusters without losing the ferromagnetic identity. The presence of multiple $A$-site cations in high entropy oxides results in a local deformation of the ${\mathrm{MnO}}_{6}$ octahedra. This possibly increases the carrier localization followed by reducing the length scale of the double exchange interaction.

A new Cambrian frondose organism: ‘Ediacaran survivor’ or convergent evolution?

Guangweia cheni gen. et sp. nov. is an exceptionally preserved frond-like fossil from the early Cambrian Guanshan biota of SW China, which shares morphological similarities with some characteristic late Ediacaran frondose organisms in comprising a leaf-like frond attached via a stem to a discoidal structure resembling a holdfast. Plausible evidence for tissue differentiation and bilateral symmetry in G. cheni implies a eumetazoan affinity. However, G. cheni profoundly differs from Ediacaran frondose taxa in several morphological characters, including its possession of an unusual wedge-shaped apical structure. These observations preclude direct phylogenetic relationships with known Ediacaran forms. Instead, G. cheni may record convergent evolution of a frondose bodyplan: a possibility that should be entertained for other purported Cambrian frondose taxa. Supplementary material: A supplementary figure and sketch, scanning electron microscope–energy dispersive X-ray (SEM-EDX) elemental maps and spectra, and detailed images, interpretative drawings and measurements are available at https://doi.org/10.6084/m9.figshare.c.6294893 Thematic collection: This article is part of the Advances in the Cambrian Explosion collection available at: https://www.lyellcollection.org/topic/collections/advances-in-the-cambrian-explosion

Cytophilic Agarose-Epoxide-Amine Cryogels Engineered with Granulated Microstructures.

Inherent cytophobicity of agarose limits its direct use for the growth of anchorage-dependent cells. Here, we report a simple strategy allowing the development of agarose-based hydrogels entailed with both cytophilicity and microstructured morphology. Through the reaction of water-soluble 1,4-butanediol diglycidyl ether (BDDE) with trifunctional polyetheramine Jeffamine T403 in agarose solution followed by cryogelation of the mixtures, a series of macroporous agarose-epoxide-amine cryogels were prepared readily. Results from fluorescent labeling and energy-dispersive X-ray elemental mapping showed the formation of granulated microstructures in the cryogels. Such features closely correlated to the phase separation of BDDE-T403 polymers within the agarose matrix. Cytophilicity of the microstructured cryogels due to the integrated amine moieties was demonstrated through the adhesion of fibroblasts. Functional enrichment of the cryogels was further highlighted by leveraging the granulates as micro-reservoirs for polyphenol proanthocyanidin to enable antioxidation and protection of fibroblasts from H2O2-induced cytotoxic effect in vitro.

Structural and photon/neutron attenuation features of PbNi/CNT nanocomposites: An experimental approach

In this work, PbNi/CNT nanocomposites were prepared by sodium borohydride method at varying metallic molar ratios for determination of their structural and nuclear radiation shielding properties. As-prepared PbNi/CNTs were characterized by using transmission electron microscopy (TEM), scanning electron microscopy energy-dispersive X-ray spectroscopy (SEM-EDX), elemental mapping, and X-ray diffraction (XRD). Average particle sizes of Pb40Ni60/CNT, Pb60Ni40/CNT, Pb80Ni20/CNT, and Pb20Ni80/CNT materials were obtained as 5.6, 3.8, 4.2, and 4.2 nm, respectively. Radiation attenuation properties of the produced nanocomposites were investigated experimentally by irradiating the samples with gamma photons in the 34–383 keV energy range. The accuracy of the experimental results was checked with outcomes calculated with EpiXS software. Mass attenuation coefficient (MAC) was found in the range of 22.924–0.108 cm2/g, 5.473–0.129 cm2/g, 3.767–0.109 cm2/g, and 4.626–0.128 cm2/g for Pb20Ni80/CNT, Pb80Ni20/CNT, Pb40Ni60/CNT, and Pb60Ni40/CNT samples, respectively. Also, other photon shielding parameters (HVL, Zeff, EABF, and EBF) were calculated to make a comprehensive evaluation. The results show that 30% by weight Pb80Ni20 doped CNT has the lowest HVL and buildup factors values and the largest MAC, Zeff values. Finally, macroscopic cross-section values (ΣR) were obtained to estimate the ability of the nanocomposite samples to reduce the energy of fast neutrons. It was revealed that the ΣR values of the samples were in the range of 0.158–0.169 cm−1 and they had higher ΣR values than conventional neutron moderators.

Preparation and characterization of doped hollow carbon spherical nanostructures with nickel and cobalt metals and their catalysis for the green synthesis of pyridopyrimidines.

Fused heterocyclic systems containing the pyrimidine ring structure perform a significant role in numerous biological and pharmaceutical processes. Their properties include antibacterial, antifungal, anti-fever, anti-tumor, and antihistamine. As pyridopyrimidines are important in the essential fields of pharmaceutical chemistry, efficient methods for preparing these heterocycles are presented. In this study, a method for producing improved hollow carbon sphere nanostructures with cobalt and nickel (Co-Ni@HCSs) is presented. The nanocatalyst was prepared and identified by applying Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET), and elemental mapping techniques. The Co-Ni@HCSs nanocatalyst was proved to be highly efficient in synthesizing pyranopyrimidine derivatives. The sizeable active site, economic catalyst loading, easy workup, reusability, green reaction conditions, and excellent yields of all derivatives are some of the significant features of this process. Also, applying response surface methodology (RSM) and the Box-Behnken design (BBD) techniques allowed us to determine the influential factors of the laboratory variables and identify the optimum conditions for superior catalytic activity. Finally, synthesized organic compounds were identified by utilizing melting point, FT-IR, and hydrogen-1 nuclear magnetic resonance (1H NMR) analyses.

A 5-aminoisophthalic acid low molecular weight gelator based novel semiconducting supramolecular Zn(ii)-metallogel: unlocking an efficient Schottky barrier diode for microelectronics.

A novel method has been successfully developed for creating supramolecular metallogels using zinc(ii) ions and 5-aminoisophthalic acid as the gelator (low molecular weight gelator) in a dimethylformamide (DMF) solvent at room temperature. Comprehensive rheological investigations confirm the robust mechanical strength of the resulting zinc(ii)-metallogel. Microstructural analysis conducted through field-emission scanning electron microscopy (FESEM) unveils a unique flake-like morphology, with energy-dispersive X-ray (EDX) elemental mapping confirming the prevalence of zinc as the primary constituent of the metallogel. To understand the formation mechanism of this metallogel, Fourier-transform infrared (FT-IR) spectroscopy was employed. Notably, these supramolecular zinc(ii)-metallogel assemblies exhibit electrical conductivity reminiscent of metal-semiconductor (MS) junction electronic components. Surprisingly, the metallogel-based thin film device showcases an impressive electrical conductivity of 1.34 × 10-5 S m-1. The semiconductor characteristics of the synthesized zinc(ii)-metallogel devices, including their Schottky barrier diode properties, have been extensively investigated. This multifaceted study opens up a promising avenue for designing functional materials tailored for electronic applications. It harnesses the synergistic properties of supramolecular metallogels and highlights their significant potential in the development of semiconductor devices. This work represents a novel approach to the creation of advanced materials with unique electronic properties, offering exciting prospects for future innovations in electronic and semiconductor technologies.

Polyaniline-polycaprolactone electrospun nanofibrous mat: new polymeric support with anion exchange characteristic for immobilizing liquid membrane in efficient on-chip electromembrane extraction of polar acidic drugs.

The potential of application of an electrospun nanofiber sheet as new polymeric support for immobilizing the liquid membrane, instead of a common commercial polypropylene sheet, in on-chip electromembrane extraction (EME) of some acidic polar drugs followed by HPLC with ultraviolet detection is presented. The nanofiber sheet was prepared by electrospinning a mixture of polycaprolactone and polyaniline. The successful synthesis of the electrospun nanofiber sheet was confirmed by field emission-scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, and atomic force microscopy. Several parameters affecting the efficiency of the microextraction method, including pHs of the donor and acceptor phases, applied voltage, sample flow rate, phosphate content of the acceptor phase, and sample volume, were investigated and optimized. After optimization, the linearity range of 0.5-250.0µg L-1 and detection limits of 0.2-1.0µg L-1 were obtained for the analytes. The extraction recovery values and preconcentration factors were 10.7-55.3% and 16-83, respectively. The presence of polyaniline in the composition of the nanofibers significantly improved the extraction efficiency of the polar acidic drugs due to providing the possibility of various interactions with the target analytes such as hydrogen bonding, π-stacking, andanion exchange. The obtained results demonstrate the excellent efficiency of the synthesized electrospun nanofibrous mat as a novel support membrane for immobilizing 1-octanol and as an interactive substrate for electromembrane extraction of acidic polar drugs. Eventually, the proposed on-chip EME method exhibits acceptable precision (relative standard deviations less than 9.7% (n = 3)) and good accuracy (86-112%) for determining the target analytes in the plasma samples.

A new copper-supported zinc ferrite as a heterogeneous magnetic nanocatalyst for the synthesis of bis(pyrazolyl)methanes and oxidation of sulfides

In this paper, we report the synthesis of ZnFe2O4@SiO2@APTES@DHBS-Cu as a novel magnetic nanocatalyst, in a mild and green environment. The structure of the described magnetic compound was characterized by different physicochemical techniques including XRD, EDS, AAS, SEM, FT-IR, X-ray elemental mapping, TGA, and VSM analyses. The prepared magnetic nanoparticles exhibit excellent catalytic activity in synthesizing bis (pyrazolyl)methanes and oxidation of sulfide derivatives under green conditions. The heterogeneous nature of the catalyst was confirmed via the hot filtration experiment. Further, ZnFe2O4@SiO2@APTES@DHBS-Cu showed high efficiency and reusability that could be reused for at least five consecutive runs.

Cu-ZIF@ red soil nanocomposite sufficient sorbent for dye removal

In this study, Cu-ZIF and Cu-ZIF@ Red soil Nano composite were synthesized in room temperature. Red soil, Cu-ZIF and Cu-ZIF@ Red soil Nano composite were fully characterized by different techniques such as Fourier transform spectroscopy infrared (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), elemental mapping, BET and thermal gravimetric analysis (TG). The results of FESEM indicated Cu-ZIF@ Red soil had meso porous nature with uniform spherical shape of 30 nm. The XRD result showed the main phase of red soil was hematite (Fe2O3) and hexagonal crystal system (primitive R3) and α-SiO2 and the crystal structure of red soil and Cu-ZIF remain unchanged after formation of composite. Adsorption of malachite green (MG) by prepared samples were studied. The highest percent of MG adsorption was occurred at contact time of 60 min, pH 10, and adsorbent dose of 0.1 g. Kinetic studies indicated that the adsorption of MG follows by pseudo second-order model. Thermodynamic results revealed that the adsorption of MG is endothermic, spontaneously process and feasible in the range of 298–338 K. The adsorption isotherm experimental data was fitted better by Langmuir model than Freundlich model. The maximum adsorption capacity of MG for Red soil, Cu-ZIF and Cu-ZIF@ Red soil Nano composite was observed 132, 366.6 and 382 mg g−1, respectively at pH 10. Cu-ZIF@ Red soil Nano composite acts as sufficient reusable sorbent for MG dye.

Microstructural characterization, hardness and impact behavior of AA7075/steel slag surface composites fabricated through multipass friction stir process

Aluminium-based Surface Composites (SCs) fabricated through Friction Stir Process (FSP) with excellent hardness and impact strength are predominantly suited for piston skirt applications. This paves the way for the exploration of multipass effects in steel slag-reinforced AA7075 SCs for analysis of microstructure, hardness and impact strength. Microstructural examination reveals the homogenous distribution of steel slag particulates on the matrix and on increasing the number of FSP passes, the grain size is reduced. Furthermore, a clear interface is obtained between the reinforcements and base AA7075 matrix identified through the macrostructure. X-Ray Diffraction technique (XRD) and Elemental mapping with Energy Dispersive Spectroscopy (EDS) confirm the existence and dispersion of reinforcing constituents available in the composite layer. The superior microhardness along with prodigious impact strength are accomplished in the third pass. The obtained hardness results are attributed to the reduced grain size with decreased oxide content. The enhanced tendency of the reinforcements to blockade the crack initiation and its propagation results in high-impact strength. In addition, the fractography of impact testing specimens is evaluated through SEM and reveals that the ductile mechanism is a dominant failure mode.

K původu analcimu v mezozoických a kenozoických vulkanitech České republiky a jeho úloze v názvosloví hornin

Magmatic origin of analcime has been discussed for decades (e. g., Karlsson and Clayton 1991, 1993; Pearce 1993). Despite the fact that analcime has been re-classified as zeolite and its secondary (post-magmatic) origin is globally accepted (e. g., Roux and Hamilton 1976, Giannetti and Masi 1989, Wilkinson and Hensel 1994), it is still commonly used in classification of alkaline rocks in the Czech Republic. In these rocks, analcime can be mostly found in the pseudomorphs after leucite (Fig. 1a; see Rapprich 2003), or as a homogeneous anhedral filling in the groundmass (Fig. 1b). In the second case, the boundaries of individual analcime crystals cannot be identified due to the isotropic optical properties of analcime. Therefore, origin and growth of analcime is difficult to reconstruct. For this contribution, we have studied samples of Mesozoic and Cenozoic alkaline rocks from three localities across the Czech Republic, where partly analcimized glass in the groundmass was preserved, with an aim to better understand the origin of analcime in alkaline rocks. Mesozoic augitite from the southwestern slope of the Petřkovice Mt. near Nový Jičín (sample TG05) displays small isometric colourless, optically isotropic domains (analcime) enclosed in originally glassy groundmass (Fig. 1c–f ). This texture suggests the analcime is replacing original glass in the groundmass, enclosing also microcrysts of the stable minerals in groundmass. Very similar texture was observed also in Oligocene augitite from Mětikalov in Doupovské hory Mts. (sample DR338, Fig. 2). In this rock, the analcime domains either mantle larger phenocrysts, or are distributed within the groundmass. The growth of the analcime domains on the edges of larger phenocrysts resembles growth of spherulites, which represent products of silica-rich glass recrystallization (e. g., Breitkreuz 2013). To further investigate this possibility, additional samples were collected from Kamenický vrch near Zákupy (Fig. 3). In individual samples, number and size of analcime domains vary, which suggests, that these domains represent various stages of a continuous growth. The X-ray elemental mapping of Al and Na (Fig. 4) then shows, that the analcime domains are represented by single grains of cubic analcime. As a result, we may conclude that analcime in groundmass of Mesozoic and Cenozoic alkaline rocks originates from devitrification of original glass. These rocks hence should not be classified as “analcimites” or “analcimic …” but rather as “analcimized …” according to Le Maitre et al. (2005).