Sulfide Solution Research Articles

Взаимосвязь электронной и атомной структуры пассивированных поверхностей n-InP(100)

Photoluminescence, Raman spectroscopy and X-ray photoelectron spectroscopy are used to study electronic and atomic structure of n-InP(100) surfaces treated with different sulfide solutions. It is shown that the sulfide treatment causes removal of the native oxide layer from the semiconductor surface and formation of the passivating layer consisting of In−S chemical bonds with the structure dependent on the solution composition and atomic arrangement at the initial surface of the semiconductor. This is accompanied by an increase in photoluminescence intensity and narrowing of the surface depletion layer. Atomic structure of the passivating layer determines the total dipole that modifies the depth distribution of the bands potentials and thus the surface electronic structure.

Correlation of the electronic and atomic structure at passivated n-InP(100) surfaces

Photoluminescence, Raman spectroscopy and X-ray photoelectron spectroscopy are used to study electronic and atomic structure of n-InP(100) surfaces treated with different sulfide solutions. It is shown that the sulfide treatment causes removal of the native oxide layer from the semiconductor surface and formation of the passivating layer consisting of In-S chemical bonds with the structure dependent on the solution composition and atomic arrangement at the initial surface of the semiconductor. This is accompanied by an increase in photoluminescence intensity and narrowing of the surface depletion layer. Atomic structure of the passivating layer determines the total dipole that modifies the depth distribution of the bands potentials and thus the surface electronic structure. Keywords: surface modification, sulfur passivation, Raman spectroscopy, photoluminescence, X-ray photoelectron spectroscopy.

Enhanced Photocatalytic Activity for Degradation of Ofloxacin and Dye by Hierarchical Flower-Like Zns/Mos2/Bi2wo6 Heterojunction: Synergetic Effect of 2d/2d Coupling Interface and Solid Sulfide Solutions

Enhanced Photocatalytic Activity for Degradation of Ofloxacin and Dye by Hierarchical Flower-Like Zns/Mos2/Bi2wo6 Heterojunction: Synergetic Effect of 2d/2d Coupling Interface and Solid Sulfide Solutions

Trace and minor elements in sulfides from the Lengshuikeng Ag–Pb–Zn deposit, South China: A LA–ICP–MS study

Sphalerite, pyrite and galena are common sulfide minerals in Zn–Pb–(Ag) deposits, containing minor and trace elements that can be used to constrain the ore-forming processes. The Lengshuikeng Ag–Pb–Zn deposit (LSKD) is one of the largest silver deposits in China. The mode of silver occurrence in sulfides remains unclear except for individual silver minerals. In this study, we analyzed the minor and trace element contents of sulfide minerals from massive, vein, and veinlet-disseminated ores by in-situ laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS). The elemental compositions of sulfide minerals are variable. Combining petrographic observations and previous studies, we suggest that the sulfide minerals from two types of mineralization (porphyry and strata-bound types) were formed in a same hydrothermal system, and their content of minor and trace elements mainly is influenced by temperature, alteration of wall rocks and composition change of hydrothermal fluid. The Ag content in galena ranges n*103 ∼ n*104 ppm, whereas that in both sphalerite and pyrite ranges from n*10 ∼ n*103 ppm. Except for galena, a higher content of gold (mean = 0.76 ppm) and silver (mean = 151 ppm) occurs in sphalerite compared with the content of gold (mean = 0.26 ppm) and silver (mean = 69.9 ppm) in pyrite. Generally, altered samples display higher Ag and Au contents in pyrite and sphalerite. Silver occurs in the form of a solid solution in sulfides from samples with massive textures, and as micro-inclusions in sulfides from altered samples. The contents of minor and trace elements (e.g. Cd and In) and their ratios (Ga/In, Zn/Cd and Cd/Fe) are not always sensitive to the temperature and processes of deposit formation. We suggest that sulfides from samples with massive texture and limited alteration are suitable for determining the genetic type of the deposit. Our results show that the hydrothermal fluid is a magmatic fluid related to porphyry granite in the LSKD.

Obtaining Nickel Concentrates from Sludge Produced in the Process of Electrochemical Metal Surface Treatment

The article presents the possibility of recovering nickel from waste produced as a result of wastewater neutralization during the electrochemical surface treatment of metals. Leaching the sludge with concentrated hydrochloric acid enabled the metals contained in the sludge from precipitate to the solution with the efficiency of 74.4% (Se) to 100% (Zn). The content of elements was determined using the ICP-OES method. The next step was the precipitation of metals from the obtained solution using various reagents. The precipitating reagents used were 0.5 M sodium hydroxide solution, 0.5 M sodium sulphide solution and 1% dimethylglyoxime solution. Selective precipitation made it possible to obtain nickel concentrates with the content of nickel ranging from 15.3 to 98.2% for the first two methods, whereas in the case of the third method based on a dimethylglyoxime solution, the obtained nickel concentrate purity was 94.3%. The process of leaching nickel-dimethylglyoxime complex (Ni-DMG) with sulphuric acid and crystallization enabled obtaining 99.4% purity nickel sulphate, which can be reused in the nickel plating of selected metals. The research shows that waste generated in the process of neutralization of wastewater from electroplating plants is a potentially important source of recycled nickel concentrates.

Constructing g-C3N4/Cd1−xZnxS-Based Heterostructures for Efficient Hydrogen Production under Visible Light

Two types of photocatalysts, 1%Pt/Cd1−xZnxS/g-C3N4 (x = 0.2–0.3) and Cd1−xZnxS/1%Pt/g-C3N4 (x = 0.2–0.3), were synthesized by varying the deposition order of platinum, and a solid solution of cadmium and zinc sulfides onto the surface of g-C3N4. The characterization of photocatalysts showed that, for 1%Pt/Cd1−xZnxS/g-C3N4, small platinum particles were deposited onto a solid solution of cadmium and zinc sulfides; in the case of Cd1−xZnxS/1%Pt/g-C3N4, enlarged platinum clusters were located on the surface of graphitic carbon nitride. Based on the structure of the photocatalysts, we assumed that, in the first case, type II heterojunctions and, in the latter case, S-scheme heterojunctions were realized. The activity of the synthesized samples was tested in hydrogen evolution from triethanolamine (TEOA) basic solution under visible light (λ = 450 nm). A remarkable increase in hydrogen evolution rate compared to single-phase platinized 1%Pt/Cd1−xZnxS photocatalysts was observed only in the case of ternary photocatalysts with platinum located on the g-C3N4 surface, Cd1−xZnxS/1%Pt/g-C3N4. Thus, we proved using kinetic experiments and characterization techniques that, for composite photocatalysts based on Cd1−xZnxS and g-C3N4, the formation of the S-scheme mechanism is more favorable than that for type II heterojunction. The highest activity, 2.5 mmol H2 g−1 h−1, with an apparent quantum efficiency equal to 6.0% at a wavelength of 450 nm was achieved by sample 20% Cd0.8Zn0.2S/1% Pt/g-C3N4.

Trace precious metals in major sulfide minerals from the Federova Tundra platinum group element deposit in the Fedorova-Pana layered intrusion, central Kola Peninsula, Russia

ABSTRACTDrill-core samples from the basal Cu-Ni-platinum-group element mineralization of the Early Proterozoic Fedorova Tundra intrusion in the Fedorova-Pana layered intrusion, central Kola Peninsula, Russia, were studied in two separate projects in Canada and Russia. In Canada, trace precious metal analyses by laser ablation inductively coupled mass spectrometry of 323 base metal sulfide particles [pentlandite (101), pyrrhotite (98), chalcopyrite (25), and pyrite (99)] show that Pd is highly concentrated in pentlandite. Most of the analyses (71%) were done using two master composite samples of comminuted drill core representative of the West Pit and East Pit mineralization, FWMC and FEMC, respectively. Fewer analyses were made of three other comminuted drill core samples from the West Pit referred to as “lithology” samples: OLFW (olivine-bearing rocks), ANFW (leucocratic rocks), and GNFW (gabbronorite). In Russia, 120 polished sections sliced from drill core from the West and East Pits and from four other Fedorova Tundra intrusion deposits (Kievey, Northern Kamennik, Eastern Chuarvy, and Southern Kievey) were studied mineralogically. Platinum group mineral characterization and trace Pd electron probe microanalyses of pentlandite were done using polished sections from all six locations (n = 95). The trace electron probe microanalysis data for Pd in pentlandite from the West (n = 35) and East (n = 19) Pit samples, though at much higher detection levels, are considered to be comparable to the laser ablation inductively coupled mass spectrometry data. The Eastern Chuarvy samples show particularly high Pd concentrations averaging 0.49 wt.% Pd (n = 11) and as high as 1.64 wt.% Pd. The combined data from these studies guides our estimate that pentlandite accounts for 30 to 50% of the Pd in these ores and that Rh solid solution in sulfides may account for >98% of the total Rh.

Supergene mobilization and redistribution of platinum-group elements in the Merensky Reef, eastern Bushveld Complex, South Africa

ABSTRACT Near-surface supergene ores of the Merensky Reef in the Bushveld Complex, South Africa, contain economic grades of platinum-group elements, however, these are currently uneconomic due to low recovery rates. This is the first study that investigates the variation in platinum-group elements in pristine and supergene samples of the Merensky Reef from five drill cores from the eastern Bushveld. The samples from the Richmond and Twickenham farms show different degrees of weathering. The whole-rock platinum-group element distribution was studied by inductively coupled plasma-mass spectrometry and the platinum-group minerals were investigated by reflected-light microscopy, scanning electron microscopy, and electron microprobe analysis. In pristine (“fresh”) Merensky Reef samples, platinum-group elements occur mainly as discrete platinum-group minerals, such as platinum-group element-sulfides (cooperite–braggite) and laurite as well as subordinate platinum-group element-bismuthotellurides and platinum-group element-arsenides, and also in solid solution in sulfides (especially Pd in pentlandite). During weathering, Pd and S were removed, resulting in a platinum-group mineral mineralogy in the supergene Merensky Reef that mainly consists of relict platinum-group minerals, Pt-Fe alloys, and Pt-oxides/hydroxides. Additional proportions of platinum-group elements are hosted by Fe-hydroxides and secondary hydrosilicates (e.g., serpentine group minerals and chlorite). In supergene ores, only low recovery rates (ca. 40%) are achieved due to the polymodal and complex platinum-group element distribution. To achieve higher recovery rates for the platinum-group elements, hydrometallurgical or pyrometallurgical processing of the bulk ore would be required, which is not economically viable with existing technology.

Modification of the Electronic Properties of the n-InP (100) Surface with Sulfide Solutions

Modification of the Electronic Properties of the n-InP (100) Surface with Sulfide Solutions

Research on the Adsorption Effects of Biomass by Microstructural Characterization and Intelligent Numerical Computation Method

In this paper, sodium sulfide solution as a simulation of sulfur-containing wastewater, using orange peel as adsorbent, through the change of the absorbance of simulated wastewater to analyze the orange peel adsorbent on the treatment effect of simulated wastewater, to explore its optimal experimental conditions. The experimental results show that the adsorbent has a certain adsorption effect on the sulfur compounds in the sulfur-containing wastewater. With the change of the pH value of the adsorption environment, the adsorption rate has changed. The addition of different chemical modifiers in the water will affect the adsorption and effect of orange peel.

Computer Numerical Simulation and Study on Adsorption Properties of Orange Peel Using Scanning Electron Microscope

In this paper, using orange peel as raw material, based on the adsorption mechanism of orange peel, the adsorption performance of biomass adsorbent on sulfur compounds was studied. Sodium sulfide solution was used to simulate the sulfur-containing wastewater, and it was found that the orange peel biomass had a certain adsorption effect on the sulfur compounds in the wastewater. Through the control experiment, the influence of drying time and dosage of orange peel pretreatment on the adsorption effect was explored, so as to find out the best conditions for orange peel adsorption of sulfur-containing wastewater, and provide a theoretical basis for the treatment of industrial sulfur-containing wastewater.

Preparation and photocatalytic performance of CdS@Bi2WO6 hybrid nanocrystals

The hybrid nanocrystals of cadmium sulfide (CdS) and bismuth tungstate (Bi2WO6) (CdS@Bi2WO6) were well-prepared in the nanoreactors of Bi2WO6-contained sodium polyacrylate (PAANa) latex particles, by means of cadmium sulfate/sodium sulfide (CdSO4/Na2S) solutions absorption and solvothermal treatment. The influences of CdSO4/Na2S millimolar ratio on structure and photocatalytic performance of hybrid nanocrystals were investigated. With 3:1 of Cd2+/S2- millimolar ratio in feeding, CdS nanorods on the surface of Bi2WO6 cluster were obtained and its length increased after solvothermal treating; the resultant CdS@Bi2WO6 degraded 96.1% of RhB after illuminating for 120 min, which was more effective than others. With the 1:2 or 1:3 of Cd2+/S2- millimolar ratio, the solvothermal treated cubic-CdS were agglomerated to cluster which attached on the surface of Bi2WO6 cluster, and the agglomerates size increased accordingly. The photocatalytic mechanism suggests that the superoxide ions and holes were the active species produced by CdS@Bi2WO6 in the photocatalytic process. The grown CdS nanorods on the surface of Bi2WO6 had better charge separation ability than the grown CdS clusters on the surface of Bi2WO6. The CdS@Bi2WO6 hybrid nanocrystal with the definite-designed structure will possess the excellent photocatalytic performance.

Interaction of metal sulphides in films deposited from solutions of thiourea coordination compounds. Review

Metal sulphides are highly important for the technology of semiconductor film materials. The potential of these compounds has not been exhausted yet when it comes to creating optoelectronic devices, solar cells, and luminescent devices based on them. The goal of this work was to determine the nature of interaction of sulphides in polycrystalline layers of CdS–MemSn, where Me are metals of groups I–VII of the periodic table. Cadmium sulphide was chosen as the common component of all studied systems due to the great photoelectric and luminescent properties of this well-studied material.It was shown that using aerosol spray pyrolysis of the solutions of thiourea complexes, we can obtain solid solutions and chemical compounds of CdS–MеmSn at temperatures not exceeding 500 °C. The main electric, optical, and luminescent properties of the layers were described.It was established that the use of aerosol spray pyrolysis of the solutions of thiourea coordination compounds allows significantly expanding the areas of solubility during the formation of solid sulphide solutions. The specific character of solid-phase interaction and nonequilibrium of the processes occurring during the deposition of layers allow avoiding structural incompatibility of the components expressed in the form of typical factors, such as the non-uniformity of crystal structure, differences in the chemical nature of the components, and discrepancies in sizes of substituting/penetrating atoms.Under such conditions of deposition of films (the lower threshold of deposition temperatures is determined by the temperature of decomposition of the most thermally stable thiourea coordination compound and does not exceed 250 °С), the solid-phase interactions of most sulphides cannot be achieved. Therefore, the interaction occurs at the moment of thermal destruction of complex compounds due to the emerging valence opportunities of their structural fragments

Preventing failure of the anchoring system in underground coal mines

Cable bolts are commonly used as anchoring element in many underground mines. Reports on the premature failure of cable bolts in underground coal mines due to stress corrosion cracking (SCC) have been increasing in the past two decades. The previous studies found that the diffusion of atomic hydrogen into steel causes the SCC in cable bolts, which is known as hydrogen-induced stress corrosion cracking (HISCC). While the research on the mechanism of the HISCC in underground mines needs to be continued, it is essential to develop prevention measures to avoid such a failure. In this study, a variety of prevention measures that claim to prevent corrosion of steel were examined. Specifically, barrier coating, i.e., polymer, epoxy coating, as well as the sacrificial coating, i.e., hot-dip galvanising, methods were tested. Testing specimens were made by inserting loading pins between locked cable bolt king wires (coated) to simulate the in-situ stress condition. Cable bolt specimens were then fully immersed into a hydrogen sulphide solution to determine their resistance against HISCC. The test results showed that all the coatings had delayed the failure in varying degrees, but very few have significantly extended the time to fracturing. The polymer and epoxy coatings have become breached during the testing, and the failure occurred shortly after. The galvanised coating was dissolved in the testing solution and again allowed access of the solution to the steel surface, and subsequently resulted in failure. This indicates that these coatings can be potentially applied to prevent SCC failure; however, their impacts on the performance of bolts, such as their bonding with grout and bolt, still need to be considered.

New Composite Photocatalysts Based on the Solid Solutions of Cadmium Sulfide, Zinc Sulfide, Titania, and Platinum for the Photocatalytic Reduction of Carbon Dioxide with Water Vapor under Visible Light

New Composite Photocatalysts Based on the Solid Solutions of Cadmium Sulfide, Zinc Sulfide, Titania, and Platinum for the Photocatalytic Reduction of Carbon Dioxide with Water Vapor under Visible Light

XPS Study of Long-Term Passivation of GaAs Surfaces Using Saturated Ammonium Sulfide Solution under Optimum Condition

XPS Study of Long-Term Passivation of GaAs Surfaces Using Saturated Ammonium Sulfide Solution under Optimum Condition

CuS‐Carrageenan Composite Grown from the Gel/Liquid Interface

AbstractThe aim of this study is to highlight novel CuS‐carrageenan nanocomposites grown from the interface between sulfide solutions (liquid phases) and Cu‐ι‐carrageenan gels. Several parameters including pH, copper and carrageenan concentration of the hydrogel that influence the growth of the nanocomposite have been examined. The most effective parameter is the initial pH of the liquid phase, hence, three growing samples at pH 7, 10 and 13 were selected for further studies and referred as LPH7, LPH10 and LPH13. Three CuS‐carrageenan nanocomposites obtained from the three pH conditions were purified and examined in detail using several characterization techniques such as X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS). The structure, composition, properties as well as the growth mechanism of the nanocomposite have been studied. Additionally, the electrical conductivity of the nanocomposite was exploited to be used as a sensor of relative humidity and temperature.

Anodic Passivation of InSb(100) by Sodium Sulfide Solution with Additional Sulfidization Pretreatment

The MIS-structures of InSb with anodically grown dielectric coating in galvanostatic mode in sodium sulfide solution were studied. Fast and slow surface states extracted by using the C–V characteristics method. The extracted values of Dit and NF were 2 × 1011 cm–2 eV–1 and 9.2 × 1010 cm–2, respectively. The hysteresis behavior was investigated. Additional sulfidation pretreatment using (NH4)2S–ethylenglycol solution lower the value of hysteresis and 25% reduce the interface state density. The arithmetic average roughness after anodizing increases from 0.6 to 0.9 nm, but preliminary sulfidation does not significantly affect this parameter. The formed dielectric coating has sufficient film continuity for its use as a passivating coating of InSb based FPA’s.

Simulation of Early Earth Hydrothermal Chimneys in a Thermal Gradient Environment

Deep sea hydrothermal vents are self-organizing precipitates generated from geochemical disequilibria and have been proposed as a possible setting for the emergence of life. The growth of hydrothermal chimneys in a thermal gradient environment within an early Earth vent system was successfully simulated by using different hydrothermal simulants, such as sodium sulfide, which were injected into an early Earth ocean simulant containing dissolved ferrous iron. Moreover, an apparatus was developed to sufficiently cool the ocean simulant to near 0 °C in a condenser vessel immersed in a cold water bath while injecting a sulfide solution at hot to room temperatures, effectively creating an artificial chimney structure in a temperature gradient environment over a period of a few hours. Such experiments with different chemistries and variable temperaturegradients resulted in a variety of morphologies in the chimney structure. The use of ocean and hydrothermal fluid simulants at room temperature resulted in vertical chimneys, whereas the combination of a hot hydrothermal fluid and cold ocean simulant inhibited the formation of robust chimney structures. The customizable 3D printed condenser created for this study acts as a jacketed reaction vessel that can be easily modified and used by different researchers. It will allow the careful control of injection rate and chemical composition of vent and ocean simulants, which should help accurately simulate prebiotic reactions in chimney systems with thermal gradients similar to those of natural systems.

Comparative Study of the Photocatalytic Hydrogen Evolution over Cd1-xMnxS and CdS-β-Mn3O4-MnOOH Photocatalysts under Visible Light.

A series of solid solutions of cadmium and manganese sulfides, Cd1−xMnxS (x = 0–0.35), and composite photocatalysts, CdS-β-Mn3O4-MnOOH, were synthesized by precipitation with sodium sulfide from soluble cadmium and manganese salts with further hydrothermal treatment at 120 °C. The obtained photocatalysts were studied by the X-ray diffraction method (XRD), UV-vis diffuse reflectance spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and N2 low temperature adsorption. The photocatalysts were tested in hydrogen production using a Na2S/Na2SO3 aqueous solution under visible light (λ = 450 nm). It was shown for the first time that both kinds of photocatalysts possess high activity in hydrogen evolution under visible light. The solid solution Cd0.65Mn0.35S has an enhanced photocatalytic activity due to its valence and conduction band position tuning, whereas the CdS-β-Mn3O4-MnOOH (40–60 at% Mn) samples were active due to ternary heterojunction formation. Further, the composite CdS-β-Mn3O4-MnOOH photocatalyst had much higher stability in comparison to the Cd0.65Mn0.35S solid solution. The highest activity was 600 mmol g−1 h−1, and apparent quantum efficiency of 2.9% (λ = 450 nm) was possessed by the sample of CdS-β-Mn3O4-MnOOH (40 at% Mn).