Scanning Electron Microscope-energy Dispersive Spectrum Research Articles

Scientific and technical analysis of lead-barium glaze dragonfly eye beads from the Late Warring States period in China

This paper analyzed five dragonfly eye beads excavated from M176 of the Hejia Cemetery in the Late Warring States period (around 3rd c. BC) by using a super depth of field 3D microscope system (OM), scanning electron microscope-energy dispersive spectrum (SEM–EDS) and Raman spectroscopy. The analytical results confirmed that all the beads were glazed pottery and the glaze material belongs to the lead-barium-silicate (PbO-BaO-SiO2) system. The color component of the glaze is Chinese Blue (BaCuSi4O10). Three beads, M176-2, M176-3, and M176-4, were formed with an inner core support and were made in the same batch. Additionally, two weathering products, CuPb4(SO4)2(OH)6 and PbCO3, were detected on the glaze layer surface. The results of scientific and technological analysis show that these beads have differences in the composition of the body and glaze, and the color composition in the glaze layer is relatively rare in previous studies. The discovery of lead-barium glazed pottery beads from the Late Warring States period in northern China provides new evidence for further exploration into the origins and evolution of early glazed pottery. The identification of weathering products formed on the beads’ surface within an alkaline burial environment holds valuable implications for the study of weathering and deterioration in silicate artifacts.

Experimental study on erosion mechanism and pore structure evolution of bituminous and anthracite coal under matrix acidification and its significance to coalbed methane recovery

Acid fracturing is a potential method to resolve the mineralization restriction around wellbore and enhance the permeability in coalbed methane extraction. The previous study mainly focused on exploring the effect on permeability enhancement for oil reservoir. However, the performance of acid fracturing fluid in coal reservoir is still unclear. In this paper, the surface morphology and internal pore structure of coal were characterized by erosion rate test, scanning electron microscope-energy dispersive spectrum (SEM-EDS) and low-temperature nitrogen adsorption test (LT-N2GA), and the relationship between erosion rate and pore structure index of bituminous and anthracite coal under matrix acidification was obtained. The results show that the bituminous coal presented higher acid sensitivity than anthracite from no matter aspects of erosion rate, surface morphology and internal pore structure variation. The increment of erosion rate and pore structure index is increase with the coal ranks under matrix acidification, which can provide reference for the selection of acid pad fluids for acid fracturing in different coal seams.

High removal efficiency of volatile phenol from coking wastewater using coal gasification slag via optimized adsorption and multi-grade batch process

Abstract Powder adsorbent made by coal gasification slag (CGS) was used to adsorb pollutants from coking wastewater (CW). This study initially focused on the removal efficiency of volatile phenol, NH3–N, and chemical oxygen demand (COD) from CW. The removal rate of volatile phenol increased from 48.90% to 70.50% after acid precipitation of CW by 4.0 mL reagent of sulfuric acid (3.0 M) and optimization of adsorption process by central composite design-response surface methodology with optimized conditions. Volume ratio of liquid and solid adsorbent (V L/S) and pH were the significant factors in the adsorption process. Batch experiment improved the volatile phenol, NH3–N, and COD removal rate to 85.1%, 41.6%, and 77.3%, respectively. Multi-grade batch process in grade 3 made a further promotion of pollutants removal rate as 98.5%, 73.6%, and 80.5%, respectively. Scanning electron microscope-energy dispersive spectrum and Fourier-transform infrared spectrometer were used to confirm the adsorption effect. CGS-based adsorbent for CW treatment has potential advantages due to the features of good adsorption performance and low cost.

Synthesis, structure and luminescence characteristics of La3Ga5SiO14:Pr3+ phosphors

In this study, we synthesized series of La3Ga5SiO14:Pr3+ phosphors by high-temperature solid-state reactions. For the synthesized phosphors, X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive spectrum (EDS), Raman, infrared (IR), absorption, photoluminescence (PL) and photoluminescence excitation (PLE) characterizations and decay characteristics were performed. The XRD patterns indicate that the synthesized phosphors have the same D32 (P321) structure with La3Ga5SiO14 host. The SEM image and EDS pattern show the irregular morphology and the combined La, Ga, Si, O and Pr elements for the synthesized phosphors. The room temperature Raman and IR spectra show that the phonon modes of the La3Ga5SiO14:Pr3+ phosphors follow the overall mode distributions of La3Ga5SiO14 and no appreciable changes in the phonon properties are observed, indicating that the force fields in the La3Ga5SiO14:Pr3+ lattice are not strongly altered by Pr3+ doping. The UV-Vis absorption spectra show that the phosphors contain a strong absorption band and several moderate bands resulting from the 4f-5d and f-f transitions of Pr3+ ions, respectively. La3Ga5SiO14:Pr3+ phosphors produce white light when λex = 255 nm. On the basis of emission data, the concentration quenching mechanism of the Pr3+ emission was speculated as the dipole-dipole interaction. The decay time and thermal stability were investigated, and the CIE coordinates with the corresponding correlated color temperatures were also calculated.

Influence of deicing salt on the surface properties of concrete specimens after 20 years

The low temperature of ice and snow all year round in Sweden leads to the common use of deicing salt to melt the roads, but the splash of the deicing salt on the reinforced concrete (RC) on both sides of the roads brings about the deterioration of the durability of RC components. The chloride ions diffusion coefficient is an important parameter to evaluate the durability of RC. By adopting the rapid chloride migration method (RCM) and replacing chloride ions with iodide ions, the samples of concrete blocks exposed on the side of the highway for 20 years were taken. This is directly beneficial to study the influence of the type, content, and water-cement ratio of mineral additions on the diffusion and distribution of iodide ions in concrete and analyze the surface environmental effect depth of concrete. The influence of chloride ions on the pore structure and microscopic morphology of concrete also were studied by scanning electron microscope-energy dispersive spectrum and X-ray diffractometer. The results show that as the water-cement ratio increases, the surface environmental effect depth of concrete and the diffusion area of iodide ions gradually increase. Silica fume and ground granulated blast furnace slag (GGBF slag) have an impediment to the diffusion of iodide ions, especially with the high volume of the GGBF slag (about 50%), the diffusion of iodide ions is very low. In general, this research is helpful to provide some empirical ideas and suggestions for the manufacturing and durability design of concrete structures in marine environments or deicing salt road environments.

Investigation on the Influences of Curing Time on the Cracking Resistance of Semiflexible Pavement Mixture

Semiflexible pavement (SFP) is constructed by pouring grouting material into porous asphalt (PA) mixture. SFP has been widely used to address the rutting distress issues across China in recent years. However, studies on its cracking resistance are limited and the failure mechanism of the SFP mixture has not been fully explored nor understood in a comprehensive way. Moreover, the influences of the curing time on the cracking property of the SFP mixture are still not clear. To this end, the strength development and shrinkage properties of grouting materials are determined by utilizing the three-point beam bending test and the shrinkage test. The semicircular bending (SCB) test and the scanning electron microscope-energy-dispersive spectrum (SEM-EDS) are conducted in this study to investigate the cracking resistance and failure mechanism of SFP mixtures with different curing days. Results show that both the strength and shrinkage of grouting materials would develop as the curing time was extended from 0 days to 14 days. SCB test results show that SFP mixtures have higher tensile strength but a lower flexibility index (FI) than PA mixture. It is found that the cracking resistance of SFP mixture is influenced by both the grouting materials’ strength and shrinkage. SEM-EDS analysis demonstrates that the cement-asphalt interface is a stress concentration site and therefore is the weak zone where cracks would initially develop. The microcracks found in the interface zone with different curing days may contribute to the decline of the SFP mixture’s anticracking ability. This study sheds light on the further application of SFP in practical projects.

Remarkable bactericidal traits of a metal-ceramic composite coating elated by hierarchically structured surface.

SummaryA ceramic-based coating with a hierarchical surface structure was synthesized via solid-state reaction enabled by a double cathode glow discharge technique. This innovative coating comprises two distinct layers, specifically an outer layer with a well-aligned micro-pillar array and a dense inner layer. Both are composed of a face-centered cubic Cu(Co,Ni,Fe) solid solution phase together with a spinel-type Fe(Al,Cr)2O4 oxide. This coating exhibits superhydrophobicity and, yet, a very strong adhesion to water, i.e., the so-called “rose petal effect”. This coating also exhibits highly efficient antibacterial ability against both Staphylococcus aureus and Escherichia coli bacteria under both dark and visible light conditions. The excellent antibacterial property originates from the synergistic effects through the release of Cu ions coupled with photothermal activity upon light activation.

Colloidal ZnCO3 as a Powerful Depressant of Arsenopyrite in Weakly Alkaline Pulp and the Interaction Mechanism

The effects of ZnSO4 on arsenopyrite depression were studied with sodium carbonate and sodium isobutyl xanthate (SIBX) as the pH regulator and collector, respectively. In both micro and real ore flotation tests, ZnSO4 showed better depression on arsenopyrite (pH 7.5–9.0 adjusted by Na2CO3) compared with sodium humate. The depression mechanism of ZnSO4 on arsenopyrite flotation was studied by electrokinetic potential, adsorbed amount measurements, scanning electron microscope (SEM) observation and energy dispersive spectra (EDS) detection. The electrokinetic potential measurement results show a potential increase forpleas the arsenopyrite treated with ZnSO4 in the pH range 7.5–9.0, which could be attributed to the formation of the precipitated zinc carbonate (ZnCO3(S)). For arsenopyrite treated with both ZnSO4 and SIBX, the electric surface potentials also display an increase, to approximate the values with solely ZnSO4 treated, at pH 7.5–9.0, indicating the inhibition of ZnCO3(S) upon the SIBX adsorption onto arsenopyrite. Adsorption results demonstrated that SIBX adsorption onto arsenopyrite indeed was inhibited at the pH 7.5-9.0 through the sharp decrease in SIBX adsorbed amount with ZnSO4 as the depressant at this pH range. SEM observation and EDS detection results verify the formation of colloidal ZnCO3 on the arsenopyrite, with ZnSO4 as the depressant in combination with Na2CO3.

Utilization of carbonate-based tailings to remove Pb(II) from wastewater through mechanical activation

The removal of lead in water and disposal of tailings are important environmental issues that need to be addressed urgently. This work explored the feasibility of utilizing the carbonate-based tailings (CBT) for removing lead from the simulated wastewater with the aid of wet stirred ball milling (mechanical activation). Batch experiments were performed to evaluate the influences of various experimental parameters like dosage of CBT, milling balls addition and initial concentration of lead. Under the action of mechanical activated CBT, the lead removal in the solution could reach more than 99% in 2 h, and the lead removal capacity reached 832 mg/g. The results of X-Ray Diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR) and Scanning Electron Microscope-Energy Dispersive Spectra (SEM-EDS) revealed that the calcite (CaCO3) in CBT played a major role in removing lead and the lead in the solution was transferred to the precipitate as cerussite (PbCO3). The mechanical activation promoted the dissolution of calcite, reduced the particle size of CBT and peeled off the lead carbonate precipitation on the surface of calcite, thereby enabling the reaction to be efficiently and thoroughly completed. The lead content in the precipitate after the reaction reached 38.4 wt%, which made it possible for lead recovery.

Microscale control of edge defect and oxidation on molybdenum disulfide through thermal treatment in air and nitrogen atmospheres

The formation rule and mechanism of edge defect and oxidation on MoS2 through thermal treatment in air and nitrogen atmospheres were explored in this work. Atomic force microscope (AFM), X-ray photoelectron spectroscope (XPS), and scanning electron microscope-energy dispersive spectrum (SEM-EDS) demonstrated that both edge defects and surface oxidation occurred on MoS2 when being thermally treated in air atmosphere, while pure defective MoS2 structure formed in N2 atmosphere. The degrees of defect and oxidation increased with the increase of temperature and time under thermal treatment. Auger electron spectrometer (AES) revealed that the oxidation of MoS2 was limited on the top surface and the mechanism for the oxidation was the substitution of O for the top S layer. AES and SEM-EDS results suggested that the origin of defects on MoS2 in air atmosphere was a combination of MoS2 oxidation and thermal effect, while that in N2 atmosphere was simply because of the thermal effect. This work indicated that defects and oxidation on MoS2 could be well controlled through the modification of thermal temperature, atmosphere and time, which might give a significant guidance for the better application of MoS2.

Separation of chalcopyrite and pyrite from a copper tailing by ammonium humate

Abstract Copper tailings constitute a large proportion of mine wastes. Some of the copper tailings can be recycled to recover valuable minerals. In this paper, a copper tailing was studied through the chemical analysis method, X-ray diffraction and scanning electron microscope-energy dispersive spectrum. It turned out that chalcopyrite (Cu) and pyrite (S) were the main recoverable minerals in the tailing. In order to separate chalcopyrite from pyrite in low pulp pH, ammonium humate (AH) was singled out as the effective regulator. The depression mechanism of AH on the flotation of pyrite was proved by FTIR spectrum and XPS spectrum, demonstrating that there was a chemical adsorption between AH and pyrite. By Response Surface Methodology (RSM), the interaction between AH, pulp pH and iso-butyl ethionine (Z200) was discussed. It was illustrated that the optimal dosage of AH was 1678 g·t− 1 involving both the recovery of Cu and S. The point prediction by RSM and the closed-circuit flotation displayed that the qualified Cu concentrate and S concentrate could be obtained from the copper tailing. The study indicated that AH was a promising pyrite depressor in the low pulp pH from copper tailings.

Identification and investigation of halite in suspended particulate matter by X-ray diffraction & scanning electron microscope-energy dispersive spectrum in the environment of an industrial city Faisalabad (Pakistan)

Identification and investigation of halite in suspended particulate matter by X-ray diffraction & scanning electron microscope-energy dispersive spectrum in the environment of an industrial city Faisalabad (Pakistan)

Banana peel extract mediated novel route for the synthesis of palladium nanoparticles

Bio-inspired palladium nanoparticles were synthesized by using banana peel extract (BPE), a non-toxic eco-friendly material. Boiled, crushed, acetone precipitated, air-dried peel powder was used to reduce palladium chloride. The palladium nanoparticles were characterized by using UV–Visible spectroscopy, scanning electron microscope-energy dispersive spectra (SEM-EDS) and X-ray diffraction (XRD) analysis. Dynamic light scattering (DLS) studies revealed the average size of nanoparticles to be 50 nm. Fourier transform infra red spectroscopy (FTIR) implicated the role of carboxyl, amine and hydroxyl groups in the synthetic process. This paper thus describes a novel green method for the synthesis of palladium nanoparticles.

Diffusion barrier performance of nanoscale TaN x thin-film

TaN x nanoscale thin-films and Cu/TaN x multilayer structures were deposited on P-type Si(100) substrates by DC reactive magnetron sputtering. The characteristics of TaN x films and thermal stabilities of Cu/TaN x/Si systems annealed at various temperatures were studied by four-point probe(FPP) sheet resistance measurement, atomic force microscopy(AFM), scanning electron microscope-energy dispersive spectrum (SEM-EDS). Alpha-Step IQ Profilers and X-ray diffraction(XRD), respectively. The results show that the surfaces of deposited TaN x thin-films are smooth. With the increasing of N 2 partial pressure, the deposition rate and root-mean-square(RMS) decrease, while the content of N and sheet resistance of the TaN x thin-films increase, and the diffusion barrier properties of TaN x thin-films is improved. TaN 1.09 can prevent interdiffusion between Cu and Si effectively after annealing up to 650 °C for 60 s. The failure of TaN x is mainly attributed to the formation of Cu 3Si on TaN/Si interface, which results from Cu diffusion along the grain boundaries of polycrystalline TaN.