Reexamining the Role of Ammonium Ions in the Sulfidization, Xanthate-Flotation of Malachite

Ammonium ions have positive effects on the sulfidization flotation of malachite; however, the underlying mechanisms remain poorly understood. In the present work, micro-flotation tests, field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and solution analysis for ammonium nitrogen were carried out. The flotation results showed positive effects of ammonium on the sulfidization flotation of malachite. Macroscopically, the sulfidized malachite produced with ammonium exhibited a darker color than that without ammonium, whereas the opposite appeared to be true for their corresponding residual liquids. FESEM images highlighted the larger particle size and higher converge density of the sulfidization product when the presence of ammonium. Furthermore, XPS results indicated a higher sulfur concentration on malachite surfaces when the presence of ammonium. XRD results showed that Cu31S16 (djurleite) and Cu7S4 (anilite) comprised the sulfidization products, regardless of the presence or absence of ammonium. However, neither EDS nor XPS analysis showed nitrogen on malachite surfaces; moreover, the residual-ratio results for ammonium nitrogen clearly demonstrated that most ammonium continued to be held in solution before and after malachite sulfidization. Based on these findings, we inferred that ammonium ions may mediate the nucleation and growth of sulfidization product during malachite sulfidization, rendering larger sulfidization product particles. The larger size of sulfidization products may result in a darker, stabler and denser sulfidization product coating layer, and then may reduce the generation of colloidal copper sulfide in the residual liquids. Ultimately, ammonium facilitates better performance of sulfidization flotation of malachite.

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Oxidation of Alloy-X in Subcritical, Transition, and Supercritical Water

CORROSION ◽

10.5006/3881 ◽

2021 ◽

Author(s):

Zachary Karmiol ◽

Dev Chidambaram

Keyword(s):

Supercritical Water ◽

Photoelectron Spectroscopy ◽

Focused Ion Beam ◽

Elevated Temperatures ◽

Subcritical Water ◽

Ion Beam ◽

X Ray Diffraction ◽

X Ray ◽

Nickel Based Superalloy ◽

Before And After

This work investigates the oxidation of a nickel based superalloy, namely Alloy X, in water at elevated temperatures: subcritical water at 261°C and 27 MPa, the transition between subcritical and supercritical water at 374°C and 27 MPa, and supercritical water at 380°C and 27 MPa for 100 hours. The morphology of the sample surfaces were studied using scanning electron microscopy coupled with focused ion beam milling, and the surface chemistry was investigated using X-ray diffraction, Raman spectroscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy before and after exposure studies. Surfaces of all samples were identified to comprise of a ferrite spinel containing aluminum.

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Characterization of X-ray irradiated graphene oxide coatings using X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy

Powder Diffraction ◽

10.1017/s0885715613000109 ◽

2013 ◽

Vol 28 (2) ◽

pp. 68-71 ◽

Cited By ~ 40

Author(s):

Thomas N. Blanton ◽

Debasis Majumdar

Keyword(s):

Atomic Force Microscopy ◽

Graphene Oxide ◽

Photoelectron Spectroscopy ◽

High Energy ◽

X Ray Diffraction ◽

Carbon Phase ◽

X Ray ◽

Force Microscopy ◽

Atomic Force ◽

Before And After

In an effort to study an alternative approach to make graphene from graphene oxide (GO), exposure of GO to high-energy X-ray radiation has been performed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) have been used to characterize GO before and after irradiation. Results indicate that GO exposed to high-energy radiation is converted to an amorphous carbon phase that is conductive.

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A study of adsorption and absorption mechanisms of copper in palygorskite

Clay Minerals ◽

10.1180/claymin.2008.043.2.04 ◽

2008 ◽

Vol 43 (2) ◽

pp. 195-203 ◽

Cited By ~ 7

Author(s):

Y. F. Cai ◽

J. Y. Xue

Keyword(s):

Photoelectron Spectroscopy ◽

Esr Spectra ◽

X Ray Diffraction ◽

X Ray ◽

Tetrahedral Sites ◽

Octahedral Cation ◽

Spin Resonance ◽

Before And After ◽

Cu Ions ◽

Complex Ion

AbstractDesorption experiments performed on four Cu-adsorbed palygorskites suggest that the leached Cu2+ ion originates at the surface and/or net-like interstice of the palygorskite fibres. The leached fraction, calculated from the quantities of adsorbed Cu2+ before and after desorption, is <1%. This may indicate that the majority of Cu is in inaccessible structural sites. X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared (FTIR) spectroscopy and electron spin resonance (ESR) were used to determine the mineralogical character of the Cu-adsorbed palygorskite. Two photoelectron lines at 932.5 and/or 933.7 eV in the narrow scan Cu 2p3/2 spectra show that Cu adsorbed on the surface of palygorskite is in the Cu+ and Cu2+ state. The stretching vibrations of the octahedral cation shift ~3–5 cm–1 towards a greater wavenumber in the FTIR spectra of Cu-adsorbed palygorskite. It can be deduced that the Cu2+ is trapped in the channel of the palygorskite structure. The ESR spectra of the palygorskite give g values of 2.34, 2.12, 2.08 and 2.05, suggesting that some Cu ions cannot be reached by H+. These results confirm that Cu is adsorbed by palygorskite via three possible mechanisms: (1) the Cu is adsorbed onto the surface or in a net-like interstice, and its oxidation states are +1 and +2; (2) Cu forms a complex ion – [Cu(H2O)4]2+ or [Cu(H2O)6]2+, and is trapped in the channel; or (3) Cu enters into the hexagonal channel of the tetrahedral sites or the unoccupied octahedral sites of palygorskite.

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Patterning Luminescent Nanocrystalline : Eu and : Tb Particles Embedded in Hybrid Organosilica with Soft-Lithographic Techniques

Journal of Nanomaterials ◽

10.1155/2012/279810 ◽

2012 ◽

Vol 2012 ◽

pp. 1-11 ◽

Cited By ~ 3

Author(s):

Sajid U. Khan ◽

Johan E. ten Elshof

Keyword(s):

Photoelectron Spectroscopy ◽

Substrate Surface ◽

Solution Chemistry ◽

Ion Scattering ◽

X Ray Diffraction ◽

X Ray ◽

Low Energy Ion Scattering ◽

Pattern Shape ◽

Secondary Ion

Eu3+-doped LaPO4and Tb3+-doped CePO4luminescent nanoparticles embedded in hybrid organosilica were patterned by two soft lithographic techniques. The role of various parameters such as solution chemistry, thermal protocols, and modification of the mold-substrate surface energies related to pattern shape formation and adhesion to the substrates have been studied. The shrinkage of the oxide patterns and shape evolution during the process was also examined. The patterns were characterized with optical and photoluminescence (PL) microscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Compositional analyses were carried out with X-ray photoelectron spectroscopy (XPS), low-energy ion scattering (LEIS), and secondary ion mass spectroscopy (SIMS). The results indicated that the final patterns obtained with these two techniques for the same material have different shapes and adherence to the substrates.

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Sorption of Molybdates and Tungstates on Functionalized Montmorillonites: Structural and Textural Features

Materials ◽

10.3390/ma12142253 ◽

2019 ◽

Vol 12 (14) ◽

pp. 2253 ◽

Cited By ~ 2

Author(s):

Magdalena Tuchowska ◽

Barbara Muir ◽

Mariola Kowalik ◽

Robert P. Socha ◽

Tomasz Bajda

Keyword(s):

Photoelectron Spectroscopy ◽

Low Cost ◽

Inorganic Compounds ◽

Ammonium Bromide ◽

Reaction Products ◽

X Ray Diffraction ◽

X Ray ◽

Before And After ◽

Mineral Sorbent ◽

Dimethyl Ammonium

Montmorillonite—the most popular mineral of the smectite group—has been recognized as a low-cost, easily available mineral sorbent of heavy metals and other organic and inorganic compounds that pollute water. The aim of this work was to determine the sorption mechanism and to identify the reaction products formed on the surface of montmorillonite and organo-montmorillonite after sorption of molybdates (Mo(VI)) and tungstates (W(VI)). Montmorillonites are often modified to generate a negative charge on the surface. The main objective of the study was to investigate and compare the features of Na-montmorillonite (Na-M), montmorillonite modified with dodecyl trimethyl ammonium bromide (DDTMA-M), and montmorillonite modified with didodecyl dimethyl ammonium bromide (DDDDMA-M) before and after sorption experiments. The material obtained after sorption was studied by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The XRD pattern showed the presence of a new crystallic phase in the sample that was observed under an SEM as an accumulation of crystals. The FTIR spectra showed bands related to Mo–O and W–O vibration (840 and 940 cm−1, respectively). The obtained results suggest that molybdenum(VI) and tungsten(VI) ions sorb onto the organo-montmorillonite in the form of alkylammonium molybdates and tungstates.

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Additive-Coated Si3N4 Powder Prepared By The Sol-Gel Method

MRS Proceedings ◽

10.1557/proc-346-667 ◽

1994 ◽

Vol 346 ◽

Author(s):

Manzheng Ge ◽

Honghua Kan ◽

Hui Yang ◽

Jianmin Qiao ◽

Zhonghua Jiang

Keyword(s):

Photoelectron Spectroscopy ◽

Coating Layer ◽

Sol Gel ◽

Particle Size Analysis ◽

Size Analysis ◽

X Ray Diffraction ◽

Gel Method ◽

X Ray ◽

Sol Gel Method ◽

Electron Microscopies

ABSTRACTThe Y2O3-La2O3 additive-coated Si3N4 powders of about 1.5 μm in size were prepared by the sol-gel method. X-ray diffraction, X-ray photoelectron spectroscopy, differential thermal analysis, thermogravimetric analysis, electron microscopies, and particle size analysis were used to study the coating on the Si3N4 particles. The results show that properties of the bulk Si3N4 powder are not affected by using the sol-gel coating and the powders are homogeneously coated by a thin layer of the Y2O3-La2O3 additives. The structure of the Y2O3-La2O3 coating layer is amorphous or microcrystalline with a submicron thickness. The coated powders are then more sinterable, and the mechanical properties of the ceramics prepared from such powders are improved.

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Stability and deactivation research of RuO2-PdO/Ti electrode in dye water degradation

Water Science & Technology ◽

10.2166/wst.2014.253 ◽

2014 ◽

Vol 70 (5) ◽

pp. 757-762 ◽

Cited By ~ 2

Author(s):

Lin Du ◽

Jin Wu ◽

Guiying Li ◽

Changwei Hu

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Coating Layer ◽

Titanium Substrate ◽

Catalytic Degradation ◽

X Ray Diffraction ◽

X Ray ◽

Water Degradation ◽

Scanning Electron

RuO2-PdO/Ti electrode was prepared and used for the electro-catalytic degradation of Active Red K-2BP. It was found that the electrode was very stable in the process. A discoloration rate of 96.2% could still be achieved on the electrode after being used for 100 runs. X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscopy characterizations of the electrode were carried out. Results showed that the deactivation of the electrode was caused by the reconstruction and oxidation of titanium substrate as well as by the coverage of the active phases on the surface of the electrode by silicon. The cracks on the coating layer also contributed to the deactivation.

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Dehydrogenation/rehydrogenation mechanism in aluminum destabilized lithium borohydride

Journal of Materials Research ◽

10.1557/jmr.2009.0328 ◽

2009 ◽

Vol 24 (8) ◽

pp. 2720-2727 ◽

Cited By ~ 9

Author(s):

Xuebin Yu ◽

Guanglin Xia ◽

Zaiping Guo ◽

Huakun Liu

Keyword(s):

Photoelectron Spectroscopy ◽

Hydrogen Desorption ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Lithium Borohydride ◽

Hydrogen Storage Properties ◽

X Ray ◽

Before And After ◽

Storage Properties ◽

Desorption Cycle

LiBH4/Al mixtures with various mol ratios were prepared by ball milling. The hydrogen storage properties of the mixtures were evaluated by differential scanning calorimetry/thermogravimetry analyses coupled with mass spectrometry measurements. The phase compositions and chemical state of elements for the LiBH4/Al mixtures before and after hydrogen desorption and absorption reactions were assessed via powder x-ray diffraction, infrared spectroscopy, and x-ray photoelectron spectroscopy. Dehydrogenation results revealed that LiBH4 could react with Al to form AlB2 and AlLi compounds with a two-step decomposition, resulting in improved dehydrogenation. The rehydrogenation experiments were investigated at 600 °C with various H2 pressure. It was found that intermediate hydride was formed firstly at a low H2 pressure of 30 atm, while LiBH4 could be reformed completely after increasing the pressure to 100 atm. Absorption/desorption cycle results showed that the dehydrogenation temperature increased and the hydrogen capacity degraded with the increase of cycle numbers.

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Structural Characterizations of Palladium Clusters Prepared by Polyol Reduction of [PdCl4]2−Ions

Journal of Analytical Methods in Chemistry ◽

10.1155/2016/9073594 ◽

2016 ◽

Vol 2016 ◽

pp. 1-6 ◽

Cited By ~ 5

Author(s):

Loredana Schiavo ◽

Lucrezia Aversa ◽

Roberta Tatti ◽

Roberto Verucchi ◽

Gianfranco Carotenuto

Keyword(s):

Photoelectron Spectroscopy ◽

Chemical Properties ◽

Nucleating Agent ◽

X Ray Diffraction ◽

Palladium Clusters ◽

X Ray ◽

Transmission Electron ◽

Hydrogen Technology ◽

Physical And Chemical

Palladium nanoparticles are of great interest in many industrial fields, ranging from catalysis and hydrogen technology to microelectronics, thanks to their unique physical and chemical properties. In this work, palladium clusters have been prepared by reduction of [PdCl4]2−ions with ethylene glycol, in the presence of poly(N-vinyl-2-pyrrolidone) (PVP) as stabilizer. The stabilizer performs the important role of nucleating agent for the Pd atoms with a fast phase separation, since palladium atoms coordinated to the polymer side-groups are forced at short distances during nucleation. Quasispherical palladium clusters with a diameter of ca. 2.6 nm were obtained by reaction in air at 90°C for 2 hours. An extensive materials characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and other characterizations (TGA, SEM, EDS-SEM, and UV-Vis) has been performed in order to evaluate the structure and oxidation state of nanopalladium.

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Study of a Hydrogen Inhibition Method with Sodium Tungstate for Wet Aluminum Dust Removal Systems

Coatings ◽

10.3390/coatings10050431 ◽

2020 ◽

Vol 10 (5) ◽

pp. 431

Author(s):

Bohan Zhang ◽

Kaili Xu ◽

Xin Zheng ◽

Xiwen Yao ◽

Yantong Wang ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Sodium Tungstate ◽

Dust Removal ◽

Explosion Hazard ◽

X Ray Diffraction ◽

Aluminum Particles ◽

X Ray ◽

Before And After ◽

Fire And Explosion ◽

Hydrogen Inhibition

Hydrogen, which can be produced due to the accumulation of aluminum dust that reacts with water in wet dust removal systems, is a fire and explosion hazard. To reduce hydrogen production, sodium tungstate is used in hydrogen inhibition experiments to inhibit the reaction between aluminum dust and water. The purity of the aluminum powder was 95.15%, analyzed with X-ray fluorescence spectrometry (XRF). Each of the hydrogen inhibition experiments lasted for 12 h. In addition, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the surface morphology and composition of particles before and after the experiments. There was nearly no hydrogen produced when the concentration of the sodium tungstate solution reached 100 g/L. The results show that a protective coating containing W element was formed on the surface of the aluminum particles after the reaction with sodium tungstate, and the coating prevented the aluminum particles from contacting with water.

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