Scanning Electron Microscopy Energy-dispersive X-ray Analysis Research Articles

Impregnation of poplar wood with multi-functional composite modifier and induction of in-situ polymerization by heating

Herein, a modified wood with greatly improved mechanical properties and reduced hygroscopicity was successfully prepared. The effects of the impregnation of multi-functional composite modifier on the chemical, thermal and morphological properties of poplar wood were also studied by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analyzer (TGA) and Scanning Electron Microscopy- Energy-Dispersive X-ray Analysis (SEM-EDXA). The multi-functional composite modifier was fabricated by methylolurea, dimethylol dihydroxy ethylene urea (DMDHEU), carbamide and silica sol. Cross-linking reaction happened between the wood cell wall and the multi-functional composite modifier. The position peaks in the XRD pattern didn’t change obviously, which indicated the crystal structure of cellulose was not noticeably affected by the chemical modification. The FT-IR analysis showed that the intensity of hydroxyl (-OH) and carbonyl (C = O) absorption peaks decreased, which was attributed to the -NHCH2OH of the modifier reacted with the hydroxyl and carbonyl of the wood. Meanwhile the Si-O-Si bond and Si-O-C bond formed between the wood structure and silica sol by in-situ polymerization. The TGA curve showed the thermal stability of the modified wood. The micrographs and major elements of the untreated and modified wood were observed by SEM-EDXA.

Structural and elemental characterization of glass and ceramic particles for bone surgery

ObjectiveClinically used bioceramics have been characterized previously with different kinds of methods and comparison of results have proven to be difficult due to varieties of the material properties of interest. Therefore, in this study we compared clinically commonly used bioceramics of hydroxyapatite and carbonate apatite, two bioactive glasses 45S5 and S53P4, and alumina with respect of properties which according to the present knowledge are significant for bone biology. MethodsPhysicochemical properties of the materials were characterized by various methods. Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) was used to analyze the material vibrational features. X-ray Power Diffraction (XRD) was used to characterize the material crystal structure and scanning electron microscopy-energy-dispersive x-ray analysis (SEM-EDXA) was used to evaluate the morphology and size of the materials and to calculate their oxide content. The dissolution behavior of the materials, ion release and pH changes in Tris buffer in a continuous flow-through reaction for 24-hours were determined. The change of the surface of the bioactive glasses by interfacial reaction during the Tris immersion was examined and the thickness of the surface reaction layer of the materials was studied. ResultsSEM examination showed that the particle morphology of BG 45S5, BG S53P4 and alumina particle’s surface was smooth. The surface of HAP was porous, but also CAP showed some surface porosity. An increase in the pH of the immersion solution was observed especially for BG 45S5 and BG S53P4. HAP, CAP and alumina caused only a minor increase in pH. BGs 45S5 and S53P4 showed a rapid initial release of sodium and calcium ions, followed by the release of silicon species. Minor release of sodium ions was registered for HAP, CAP and alumina. Calcium ion release was low but constant over the experimental time while only a minor initial dissolution was measured for HAP. SignificanceThe in vitro study showed differences in the materials’ properties, which are considered to be important for biological suitability and in clinical applications, such as materials tomography, ion release and pH changes.

Rapid and Local Self-Healing Ability of Polyurethane Nanocomposites Using Photothermal Polydopamine-Coated Graphene Oxide Triggered by Near-Infrared Laser.

In this study, we report the self-healing ability of polyurethane (PU) nanocomposites based on the photothermal effect of polydopamine-coated graphene oxide (PDA–rGO). Polydopamine (PDA) was coated on the graphene oxide (GO) surface, while simultaneously reducing GO by the oxidation of dopamine hydrochloride in an alkaline aqueous solution. The PDA–rGO was characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, and scanning electron microscopy–energy-dispersive X-ray analysis. PDA–rGO/PU nanocomposites with nanofiller contents of 0.1, 0.5 and 1 wt% were prepared by ex situ mixing method. The photothermal effect of the PDA–rGO in the PU matrix was investigated at 0.1 W/cm2 using an 808 nm near-infrared (NIR) laser. The photothermal properties of the PDA–rGO/PU nanocomposites were superior to those of the GO/PU nanocomposites, owing to an increase in the local surface plasmon resonance effect by coating with PDA. Subsequently, the self-healing efficiency was confirmed by recovering the tensile stress of the damaged nanocomposites using the thermal energy generated by the NIR laser.

Catalytic wet hydrogen peroxide oxidation of isoeugenol to vanillin using microwave-assisted synthesized metal loaded catalysts

• Supported metal nanoparticles (Cu, W, Mo) on a silica matrix using a one-pot microwave-assisted protocol. • Catalytic activity evaluated in the oxidation of isoeugenol into vanillin. • Moderate conversions, up to 50–60 % (for Cu-MINT). • Acceptable selectivities towards vanillin production (22–45 %). • High catalyst stability (imperceptible decrease of activity after the fourth use). Supported metal nanoparticles (Cu, W, Mo among others) have been stabilized on a silica matrix following an efficient and sustainable one-pot microwave-assisted protocol. The materials synthesized were characterized, mainly, by nitrogen adsorption desorption measurements, X-ray diffraction (XRD), scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDS). The materials exhibited large surface area and pore size in the mesopore range. The incorporation of metal particles in the silica matrix was also confirmed with particle size in a wide range between 2 and 52 nm. The catalytic activity of the resulting materials was evaluated in the catalytic wet oxidation of isoeugenol into vanillin using hydrogen peroxide as oxidant. The catalysts shown moderate conversions, up to 50–60 % for Cu-MINT with acceptable selectivity towards vanillin production (22–45 %), obtaining dimers as main side products. The stability of the catalysts was investigated as well, obtaining an imperceptible decrease after the fourth use.

Design and assembly of supercapacitor based on reduced graphene oxide/TiO2/polyaniline ternary nanocomposite and its application in electrical circuit

Supercapacitor devices are used as energy storage technology for electrical circuits. Graphene, metal oxide, and conducting polymers are used as electroactive materials to enhance energy, power density, and cycle life. The present study uses TiO2 and rGO materials, which are added to polyaniline (PANI). The nanocomposite structure can be observed using different initial feed ratios of rGO, TiO2, and aniline monomer as [rGO]o/[TiO2]o/[ANI]o = 1:5:1, 1:5:2, 1:5:3, 1:5:4, and 1:5:5. Fourier transform infrared–attenuation–transmission reflectance, scanning electron microscopy–energy-dispersive X-ray analysis, Brunauer–Emmett–Teller surface area, thermal-gravimetric analysis (TGA-DTA), X-ray diffraction (XRD), Raman spectroscopy, X-ray photon spectroscopy, and transmission electron microscopy analysis are conducted. Electrochemical performances of a ternary nanocomposite material are carried out by cyclic voltammetry, galvanostatic charge–discharge measurements, and electrochemical impedance spectroscopy (EIS). According to results, rGO/TiO2/PANI nanocomposite shows much better performance than its individual components in terms of specific capacitance, energy density, power density, and cycle life. The highest specific capacitance is obtained as Csp = 692.87 F/g at 2 mV/s for [rGO]o/[TiO2]o/[ANI]o = 1:5:4. A new real circuit model of LRs(CR1)(QR2) is adopted to our device, which supplies enough energy to the light LED lamp (1.8 V) for 3 min. As a result, rGO/TiO2/PANI nanocomposite may be used as a promote candidate for energy storage systems.

ANTIMICROBIAL ACTIVITIES OF GREEN SYNTHESIZED SILVER NANOPARTICLES FROM MARCHANTIA SP. EXTRACT: TESTING AN ALCOHOL-FREE HAND SANITIZER PRODUCT FORMULA

Common liverwort is widely distributed around the world, and its extract has antibacterial, antifungal, and antiseptic activities. This research investigated the antimicrobial activity of biosynthesized silver nanoparticles (AgNPs) from common liverwort (Marchantia sp.) and its potency as a material for hand sanitizer formulation. The green synthesis (eco-friendly and biosafe synthesis using the nontoxic reagents) of liverwort AgNPs (LAgNPs) was performed using the maceration technique and 1 mg AgNO3. Characterization of LAgNPs was carried out using UV-Vis spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy. Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) was performed to determine the nanoparticle size and elements. Then, the effectiveness of LAgNPs and LAgNPs-formulated hand sanitizer to inhibit the growth of Escherichia coli and Staphylococcus aureus was analyzed. The UV-Vis spectrophotometer results from LAgNPs at wavelength ranged from 400 to 700 nm shows an absorbance peak at 422 nm. FTIR analysis indicates that the LAgNPs were stabilized by isothiocyanate and amide, which represents the presence of various phytochemicals in the liverwort extract. The SEM-EDX analysis clearly shows that the size of the nanoparticles lies between 0.020-0.040 nm, and it contains several elements O, C, N, and Ag. Also, 75% LAgNPs concentration inhibited the growth of E.coli and S.aureus with clear zone diameter at 19.75 ± 6.13 mm and 16.25 ± 0.54 mm, respectively; whereas the formulated hand sanitizer inhibition diameter for both bacterial species was at 11.33 ± 1.03 mm and 11.00 ± 0.54 mm, respectively. The LAgNPs exhibits a promising antimicrobial activity for application in a non-alcoholic hand sanitizer product formulation.

Corrosion inhibition, adsorption and thermodynamic properties of hydrophobic-tailed imines on carbon steel in hydrochloric acid solution: a comparative study

Three hydrophobic-tailed imine compounds containing linear alkyl, branched alkyl and phenyl groups adjacent to the imine bond namely N-propylidenehexadecanehydrazide (PHH-L), N'-(2,2-dimethylpropylidene)hexadecanehydrazide (DMPHH-B) and N-phenylpropionalidene hexadecanehydrazide (PPHH-A), respectively were successfully synthesized with good yields and high purity. Inhibition properties were evaluated with the corrosion of carbon steel in 1 M HCl solution by electrochemical measurements and scanning electron microscopy-energy dispersive x-ray (SEM-EDX). Potentiodynamic polarization measurement indicates that the synthesized inhibitors were effective mixed-type inhibitors and adsorbed on the carbon steel surface following the Langmuir adsorption isotherm with the free energy of adsorption, ΔG o ads values ranging from −37.9 kJ mol−1 to −39.5 kJ mol−1 by mixed absorption involving both physisorption and chemisorption. Impedance spectroscopic analysis revealed that the inhibitors reduced the corrosion process by a charge-transfer process. SEM-EDX analysis revealed that the corrosion damage of the carbon steel surface was reduced in the presence of the inhibitors containing linear alkyl (PHH-L) and phenyl (PPHH-A) groups. In contrast, DMPHH-B, a compound with a branched alkyl group increased corrosion damage.

Development of versatile CdMoO4/g-C3N4 nanocomposite for enhanced photoelectrochemical oxygen evolution reaction and photocatalytic dye degradation applications

Fabrication of an efficient, stable, and versatile photocatalysts for the energy and environment remediation applications is an urgent task for the current researchers. In this work, we have successfully synthesized a versatile hybrid photocatalysts, i.e.; CdMoO4/g-C3N4 (CMO/CN) by a facile and simple one-pot in-situ hydrothermal method. Here CdMoO4 (CMO) microspheres were deposited on the g-C3N4 (CN) sheets. Fabricated CN, CMO, and CMO/CN composite photocatalysts were analyzed with various characterization techniques like UV–visible diffuse reflectance spectra (UV–Vis DRS), photoluminescence spectroscopy (PL), time-resolved fluorescence lifetime (TRFL), electrochemical impedance spectroscopy (EIS), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy–energy-dispersive X-ray analysis (SEM-EDX), transmission electron microscope (TEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET). The results reveal that the formation of a strong heterojunction between two semiconductors leads to the formation of active photocatalyst. Furthermore, as-synthesized materials were tested for the photoelectrocatalytic (PEC) oxygen evolution reactions (OERs) in acidic medium, and photocatalytic (PC) degradation of methylene blue (MB) under light irradiation. Among all tested samples, CMO/CN-10 has shown the highest current density 52.74 mA cm−2 at 1.95 V with lowest over potential of 0.70 mV on glassy carbon electrode for OER in acidic medium under the light irradiation. The PC degradation rate constant of CMO/CN-10 composite in MB solution is k = 2.0 × 10−2 min−1, whereas for the pure CMO and CN degradation rate constant is k = 5.7 × 10−3 min−1 and k = 1.2 × 10−2 min−1, respectively. This enhancement in PEC and PC properties is due to the fast migration of photo-induced electrons in the case of CMO/CN-10 nanocomposite. Trapping experiment results reveal the major reactive species for PC degradation of MB is •OH (hydroxyl radicals) and h+ (holes), respectively, and suitable PC reaction mechanism also proposed for CMO/CN-10 composites. Based on the above remarkable results, it would be a potential nanocomposite for the PEC oxygen evolution and PC degradation of MB under light illumination.

Pyrometallurgical Removal of Arsenic from Electrostatic Precipitators Dusts of Copper Smelting

This work describes the experimental results of pyrometallurgical removing of arsenic from the dust collected in the electrostatic copper precipitators within the gas cleaning system of a Copper Flash Smelting Furnace. The generation of dust in the copper smelting worldwide ranges from 2 - 15 wt% per ton of a copper concentrate. In Chile, copper smelters produce approximately 110 kt/y of dust with a concentration of arsenic between 1 and 15 wt%. The dust is a complex of metals oxides and sulfurs with copper concentrations greater than 10 wt% and relatively high silver concentrations. Since its high arsenic concentration, it is difficult to recover valuable metals through hydrometallurgical processes or by direct recirculation of the dust in a smelting furnace. Thus, the development of pyrometallurgical processes aimed at reducing the concentration of arsenic in the dust (<0.5 wt%) is the main objective of this study, giving particular attention to the production of a suitable material to be recirculated in operations of copper smelting. The work provides a detailed characterization of the dust including the Quantitative Evaluation of Minerals by Scanning Electron Microscopy (QEMSCAN), Scanning Electron Microscope-Energy Dispersive X-ray Analysis (SEM/EDS), X-Ray Diffraction (XRD), the elemental chemical analysis using Atomic Adsorption (AAS), and X-Ray Fluorescence (X-RF). By considering that arsenic volatilization requires a process of sulfidation-decomposition-oxidation, this work seeks to explore the roasting of mixtures of copper concentrate/dust, sulfur/dust, and pyrrhotite/dust. By the elemental chemical analysis of the mixture after and before the roasting process, the degree of arsenic volatilization was determined. The results indicated the effects of parameters such as roasting temperature, gas flow, gas composition, and the ratio of mixtures (concentrate/dust, sulfur/dust, or pyrrhotite/dust) on the volatilization of arsenic. According to the findings, the concentration of arsenic in the roasted Flash Smelting dust can be reduced to a relatively low level (<0.5 wt%), which allows its recirculation into an smelting process.

Comparative Evaluation of Newer Remineralizing Agents on Surface Characteristics of Tooth Surface After Slenderization: An In Vitro Study

Aim: The aim of the present study was to compare the effects of remineralizing agents (nano-hydroxyapatite [n-HAP], NovaMin, calcium sucrose phosphate [CaSP], and Pro-Argin) on surface characteristics of slenderized enamel using Vickers microhardness and scanning electron microscope–energy dispersive X-ray (SEM-EDX) analysis. Materials and Method: Sixty extracted premolar teeth were divided into 6 groups: group 1—natural teeth; group 2—slenderization and polishing; group 3—n-HAP; group 4—NovaMin; group 5—CaSP; and group 6—Pro-Argin. Remineralizing agents were applied for 21 days. Specimens were evaluated using Vickers microhardness and SEM-EDX analysis. A 1-way analysis of variance (ANOVA) and post-hoc Tukey honestly significant difference (HSD) test were used for intragroup comparisons. Results: Among all remineralizing agents, CaSP showed significantly maximum surface microhardness, followed by NovaMin, n-HAP, and Pro-Argin. SEM also showed increased surface roughness for all remineralizing agents. EDX showed maximum increase in mineral content obtained with CaSP. Conclusion: All remineralizing agents significantly remineralized the stripped enamel surface. CaSP demonstrated promising results by effectively and significantly remineralizing the enamel lesions as compared to other test agents.

Platy Talc, Asbestos, and Talc Fibers in the Female Genital Tract in Patients with Ovarian Cancer

Abstract Introduction/Objective Recent analyses on human tissue help inform the discussion regarding talc and ovarian cancer, by showing that, in some patients, considerable talc can migrate to multiple organ sites in the pelvic region from perineal application. Recently, we showed that birefringent particles were seen by polarized light microscopy and shown to be talc by scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDS) and/or Raman spectroscopy in surgically resected tissues from patients with ovarian carcinoma and perineal talc exposure. These sites included ovary, cervix, fallopian tube, uterine serosa, and regional lymph nodes. Fibrous talc, with greater carcinogenic potential as determined by the International Agency for Research on Cancer, may be observed in pelvic tissues. Besides ascension through the reproductive tract, particles and fibers may gain entry to pelvic organs by accessing small submucosal lymphatics in the lower part of the tract. Both platy and fibrous talc have an Mg-Si elemental signature, weight % Mg/Si ratio within 5% of the theoretical value of 0.649, and thus are distinguishable from other exogenous substances including the various subtypes of asbestos. Methods Tissue-based analytic methods (including in situ SEM, where a paraffin block is examined directly under variable pressure) are critical in the detection of talc and asbestos, particularly since they preserve architecture, and demonstrate talc and/or fibrous particles within their histologic environment; this may help inform exposure origin and pathophysiologic significance. Results We reviewed the analytic outcomes of our consultative experience to date. This showed that 180 of 196 patients with a history of perineal talc exposure had birefringent particles seen by light microscopy in surgically resected pelvic tissues, and 82 of 91 had talc confirmed by SEM/EDS. Carcinogenic fibers were found in 28/82 (34%) of these patients, with talc fibers only (19/82 patients, 23%), asbestos (7/82, 9%) or both (2/82, 2%) confirmed by SEM/EDS. Conclusion Our study confirms that talc and toxic fibers may be found in human pelvic tissues of talc-exposed patients. Because the SEM/EDS method samples only a small amount of tissue relative to what is in the paraffin block, the finding of exogenous particles by this method typically translates to a high overall particle burden, when scaled mathematically to bulk tissue.

Effectiveness and SEM-EDX analysis following bleaching with an experimental bleaching gel containing titanium dioxide and/or chitosan.

The aim of this study was to evaluate the bleaching effectiveness and mineral alterations following the use of experimental bleaching gels that included 6% hydrogen peroxide (HP), titanium dioxide (TiO2) and/or chitosan in comparison with the routinely used 35% HP bleaching gel. Thirty-six maxillary anterior teeth were divided into three groups according to bleaching agent as follows: Group 1: 6% HP + TiO2, Group 2: 6% HP + TiO2 + chitosan, Group 3: 35% HP. Tooth colour was measured with a spectrophotometer before bleaching and after sessions one and two on days 14 and 30, respectively. Colour changes were assessed with the CIEDE2000 and CIELab formulas. Mineral analysis was performed with a scanning electron microscopy-energy dispersive X-ray (SEM-EDX) device before and 14days after application. The enamel surfaces of randomly selected samples from each group were analysed by SEM. Two-way ANOVA was used to compare differences between groups. All tested materials resulted in significantly increased bleaching compared to the initial colour values (p < 0.05). Group 3 showed significantly more whitening compared to the other groups after the first and second sessions (p < 0.05). However, Group 2 presented prolonged whitening efficiency and reached a bleaching level similar to the 35% HP treatment after 14 and 30days. The results of the CIEDE2000 and CIELab formulas were found to be correlated (r > 0.6). The increases in Ca were similar in Groups 2 and 3 (p > 0.05) and were significantly higher than that in Group 1 (p < 0.05). p was similarly decreased among all groups (p > 0.05). The combination of 6% HP, chitosan and TiO2 appears to constitute a promising material for tooth whitening, showing good bleaching efficiency and acceptable mineral alterations.

Effectiveness of surfactants for unique hierarchical Mn2O3 nanomaterials as enhanced oxidative catalysts, antibacterial agents, and photocatalysts

We present the chemical-surfactant-mediated and green-surfactant-mediated synthesis of manganese (III) oxide nanoparticles prepared by the precipitation method using cetyltrimethylammonium bromide and tea extract, respectively, and their structural and optical properties. The nanoparticles were characterized by X-ray diffraction, scanning electron microscopy–energy-dispersive X-ray analysis, UV–Vis spectroscopy, and Fourier transform IR spectroscopy with regard to the diffraction pattern, phase, size, shape, composition of material, etc. The Mn2O3 nanoparticles had an orthorhombic structure with crystallite sizes of 25.96 and 13.17 nm for chemical synthesis and green synthesis, respectively. The chemically synthesized Mn2O3 nanoparticles were cubic and the green-synthesized Mn2O3 nanoparticles were spherical, with average particle sizes of 30–50 nm and 20–40 nm, respectively, and band gaps of 2.2 and 2.1 eV, respectively. The photodegradation of methylene blue was analyzed with Mn2O3 nanoparticles under solar irradiation. The present study also revealed the catalytic ability for oxidation reaction and the antimicrobial activities of the chemically synthesized and green-synthesized Mn2O3 nanoparticles, and their effectiveness was compared.

Application of coconut battery waste to graphic as an alternative electrode on primary battery cells

Coconut shell is one of the potential biomass as carbon sources. Coconut shell is converted to charcoal through the carbonization process. The potential of charcoal from coconut shells can be synthesized into graphene. Graphene is a derivative of one of the carbon allotropes, namely graphite, where carbon is in the form of thin plates with sp2 orbitals arranged hexagonally. The process of making graphene which is coconut shell dried in the sun then pyrolysis into charcoal then mixed with activated carbon as a reducing agent at 600 ° C for 1 hour to produce graphene. The graphene produced is characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX). The results by XRD analysis showed the resulting peaks were not sharp and slightly widened at the diffraction peaks at 24 ° and 44 °. The results of SEM-EDX analysis at 4000x magnification show the surface size and shape of the structure that is smaller, thinner and reduced buildup on the graphene structure. graphene that has been successfully synthesized was tested on a coin battery. The coin battery cathode which was replaced with graphene succeeded in turning on the light.&#x0D;

Effect of hydrogen peroxide bleaching on anionic groups and structures of sulfonated chemo-mechanical pulp fibers

The properties of the chemo-mechanical pulp were determined by the position and quantity of anionic groups in the pulp fibers. In this study, the effects of anion group content and structure in sulfonated mulberry stem chemo-mechanical pulp (SCMP) were investigated during the hydrogen peroxide (H2O2) bleaching process. Surface morphology and anion group structure of the pulp fibers were analyzed by scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and gas chromatography-mass spectrometry (GCMS). The results indicate that the sulfonic group content in bleached pulp decreases with the concentration of H2O2 to a minimum content of 71.53 μmol g−1, which is reduced by 22.68% in comparison to the unbleached pulp content of 92.51 μmol g−1. The content of carboxyl groups in pulp first increases and then decreases with the concentration of H2O2. The maximum carboxyl group content is 164.79 μmol g−1, which is increased by 53.97% compared with unbleached pulp at 107.03 μmol g−1. The total anion groups content of SCMP first increases and then decreases with the concentration of H2O2. FTIR and XPS analysis show that the content of anion groups on the surface of the pulp fibers increases slightly after H2O2 bleaching. GCMS analysis demonstrates that the content of uronic acid increases after H2O2 bleaching and the order of increase is 4-O-MeGlcA > GlcA > GalA. The contents of sulfonic acid group, total anion groups (TAGs) and surface anion groups (SAGs) of bleached pulp increase because of the hydroxyl group oxidation, terminal group reduction, methyl esterification of pectin and decomposition of polyxylose, resulting in the formation of new carboxyl groups and more uronic acid. This study reveals the mechanism of the effect of hydrogen peroxide bleaching on the anionic groups in the SCMP pulp, which is conducive to the development of bleaching technology for high yields of mulberry stem pulp.

Correction to: Crystal Structure and XANES Study of Defect Perovskite (Y1−xPrx)1+δBa2−δCu3O7−y Compounds Prepared by Solid State Synthesis Method

In this research, the processing and characterization of (Y1−xPrx)1+δBa2−δCu3O7−y cuprate perovskite powder were studied. The experimental powder samples of (Y1−xPrx)1+δBa2−δCu3O7−y (0 ≤ x ≤ 1) were prepared using a conventional solid-state reaction method. The starting powders in appropriate ratios were mixed with 6 mol% excess of A-site ions to reduce the amount of BaCuO2 and PrBaO3 second phases and calcined at 880 °C for 12 h in normal atmosphere. The calcined powders were investigated for phase content using X-ray diffraction technique and detailed structural parameters were obtained by Rietveld refinement. The microstructure of the powders was investigated by scanning electron microscopy (SEM). The chemical composition was carried out by energy dispersive X-ray analysis (EDS). The oxidation state and coordination of Pr and Cu were determined by X-ray absorption near edge structure (XANES) spectroscopy. It was found that high-purity (Y,Pr)BCO powders could be obtained. By the Rietveld refinement, the overall unit cell volume increased with increasing Pr content. SEM–EDS images showed that the particle size was about 1–5 μm and the elemental composition of (Y + Pr):Ba:Cu = 1:2:3. Pr and Cu XANES spectra indicated that the average formal valence was larger than 3 for Pr and 2 for Cu. However, the peak shifted to lower valence state at higher concentration of Pr.

One-pot synthesis of ZnO–Ag and ZnO–Co nanohybrid materials for photocatalytic applications

ZnO–Ag and ZnO–Co nanohybrid materials with different Ag and Co contents were successfully prepared through a simple one-pot method at room temperature in the absence of surfactants. This synthesis route is effective and environmentally friendly and can produce spherical nanoparticles with sizes between 7 and 20 nm. The nanohybrid materials were characterized by UV–vis spectroscopy, fluorescence spectroscopy, scanning electron microscopy–energy-dispersive X-ray analysis, X-ray diffraction, Fourier transform IR spectroscopy, and high-resolution transmission electron microscopy. Their photocatalytic activity was evidenced by discoloration of the synthetic diazo dye Bismarck brown Y; ZnO–Ag nanohybrid materials had greater efficiency for decolorization of the dye compared with ZnO–Co, ZnO, and TiO2. The enhanced photocatalytic activity of the ZnO–Ag nanohybrid material is due to three important aspects: (1) the oxygen vacancies present on the ZnO surface, (2) the efficient absorption of visible light due to the interaction of the semiconductor and the surface plasmon resonance of Ag, and (3) the effective separation of charges due to the formation of the Schottky barrier between ZnO and Ag, where Ag acts as an electron trap, and thereby reduces recombination. When the ZnO–Co nanohybrid is used, the addition of Co introduces intermediate energy levels between the valence and conduction bands on the semiconductor surface, which results in a recombination that reduces the photocatalytic activity, making the azo dye decolorization less efficient.

The synthesis of rGO/RuO2, rGO/PANI, RuO2/PANI and rGO/RuO2/PANI nanocomposites and their supercapacitors

In this work, reduced graphene oxide (rGO) was obtained by chemical reduction of graphene oxide (GO) using sodium borohydride (NaBH4). Four different nanocomposites rGO/ruthenium oxide (RuO2), rGO/polyaniline (PANI), RuO2/PANI and rGO/RuO2/PANI were chemically synthesized. In addition, PANI-based nanocomposites were synthesized by in situ polymerization technique. Nanocomposites were examined by different methods such as Fourier transform infrared spectroscopy–attenuated transmission reflectance, UV–Vis spectrophotometer, scanning electron microscopy–energy-dispersive X-ray analysis, thermal analysis (TGA–DTA) and transmission electron microscopy. TGA–DTA results show that the decomposition of rGO/RuO2/PANI nanocomposite (27.2% at 788.8 °C) was less than that of rGO (1% at 779.7 °C), which confirms the successful synthesis of nanocomposites. These nanocomposites can be used in supercapacitor applications. Supercapacitor device performances were taken by cyclic voltammetry (CV), galvanostatic constant current and electrochemical impedance spectroscopy (EIS) via two-electrode configuration. Ragone plots were drawn to observe energy and power densities of supercapacitor devices. Stability tests were taken by CV method for 1000 cycles. A ternary rGO/RuO2/PANI nanocomposite yields higher specific capacitance as Csp = 723.09 F g−1 than rGO/RuO2 (Csp = 347.28 F g−1), rGO/PANI (Csp = 159.62 F g−1), RuO2/PANI (Csp = 40.2 F g−1) and rGO (Csp = 37.5 F g−1) at 2 mV/s by CV method. A new electrical circuit model of LR(C(R(CR))) was used to analyze EIS data for rGO, rGO/PANI, rGO/RuO2, RuO2/PANI and rGO/RuO2/PANI nanocomposites. These nanocomposites demonstrate remarkable properties for use as electroactive materials for supercapacitor applications.

Experimental investigation of the predicted band structure modification of Mg2X (X: Si, Sn) thermoelectric materials due to scandium addition

Modification of the electronic band structure via doping is an effective way to improve the thermoelectric properties of a material. Theoretical calculations from a previous study have predicted that Sc substitution on the Mg site in Mg2X materials drastically increase their Seebeck coefficient. Herein, we experimentally studied the influence of scandium substitution on the thermoelectric properties of Mg2Si0.4Sn0.6 and Mg2Sn. We found that the thermoelectric properties of these materials are unaffected by Sc addition, and we did not find hints for a modification of the electronic band structure. The SEM-energy dispersive X-ray analysis revealed that the scandium does not substitute Mg but forms a secondary phase (Sc-Si) in Mg2Si0.4Sn0.6 and remains inert in Mg2Sn, respectively. Thus, this study proves that scandium is an ineffective dopant for Mg2X materials.

Preparation and characterization of palladium ceramic alumina membrane for hydrogen permeation

In this study, a tubular palladium membrane has been prepared by an electroless plating method using palladium II chloride as a precursor with the intent of not having a completely dense film since its application does not require high hydrogen selectivity. The support used was a 15 nm pore sized tubular ceramic alumina material that comprised of 77% alumina and 33% titania. It has dimensions of 7 mm inner and 10 mm outer diameters respectively. The catalyst was deposited on the outside tube surface using the electroless deposition process. The membrane was morphologically characterized using scanning electron microscopy/energy dispersive x-ray analysis (SEM/EDXA) and liquid nitrogen adsorption/desorption analysis (BET) to study the shape and nature of the palladium plating on the membrane. The catalytic membrane was then inserted into a tubular stainless-steel holder which was wrapped in heating tapes so as to enable the heating of the membrane in the reactor. The gases used for permeation tests comprised H2, N2, O2 and He. Permeation tests were out at 573 K and at pressure range between 0.05 and 1 barg. The results showed that hydrogen displayed a higher permeation when compared to other gases that permeated through the membrane and its diffusion is also thought to include solution diffusion through the dense portions of the palladium in addition to Knudsen, convective and molecular sieving mechanisms occurring through cracks and voids along the grain boundaries. While high hydrogen selectivity is critically important in connection with hydrogen purification for fuel cells and in catalytic membrane reactors used to increase the yield of thermodynamically limited reactions such as methane steam reforming and water–gas shift reactions whereby the effective and selective removal of the H2 produced from the reaction zone shifts the equilibrium, it is not so important in situations in which the membrane has catalytic activity such that it is possible to carryout the reaction in situations where the premixed reactants are forced-through the membrane on which the catalysts is attached. This type of catalytically active membranes is novel and has not been tested in gas-solid-liquid reactions and liquid-solid reactions before. With such a reactor configuration, it is possible to achieve good feed stream distribution and an optimal usage of the catalytic material. The preparation and characterization of such membrane catalysts has gained increased interest in the process industries because it can be adapted to carryout the chemical reactions if one of the reactants is present in low concentration and an optimal reactant distribution results in a better utilization of the active catalytic material. However, there are concerns in terms of the high cost of palladium membranes and research on how to fabricate membranes with a very low content of the palladium catalyst is still ongoing. Work is currently underway to deploy the Pd/Al2O3 membrane catalysts for the deoxygenating of water for downhole injection for pressure maintenance and in process applications.