Sodium Sulfide Solution Research Articles

Significant photoluminescence enhancement in WS2 monolayers through Na2S treatment.

Tungsten disulfide monolayers have attracted extensive attention in nanoelectronics and optoelectronics applications due to their remarkable electronic and optical properties. High-quality WS2 monolayers with a scalable size and uniform thickness can be synthesized by a chemical vapor deposition method (CVD). However, they commonly contain intrinsic structural defects and different populations of charge carriers, which are responsible for different contributions of excitons, trions, and biexcitons to their photoluminescence (PL) emission. Here, we adopt sodium sulphide (Na2S) solution to chemically treat CVD-grown WS2 monolayers by a simple immersing method. The results show that WS2 monolayers have a significantly enhanced PL emission by a factor of 25-fold and an obvious red-shift of the PL wavelength, resulting from the different excitonic states induced by effective n-type doping after Na2S treatment. This work provides a simple but promising chemical doping route to significantly improve the optical properties of WS2 monolayers and paves the way for the realization of practical WS2 monolayer based optoelectronic applications.

Coordination of the chemical and electronic processes in GaSb(100) surface modification with aqueous sodium sulfide solution

GaSb(100) surface electronic passivation with aqueous Na2S solution is driven by the redox reaction of gallium sulfide and elemental antimony formation.

Fabrication of CdS/β-SiC/TiO2 tri-composites that exploit hole- and electron-transfer processes for photocatalytic hydrogen production under visible light

In this work, CdS/SiC/TiO2 tri-composite photocatalysts that exploit electron- and hole-transfer processes were fabricated using an easy two-step method in the liquid phase. The photocatalyst with a 1:1:1 M ratio of CdS/SiC/TiO2 exhibited a rate of hydrogen evolution from an aqueous solution of sodium sulfite and sodium sulfide under visible light of 137 μmol h−1 g−1, which is 9.5 times that of pure CdS. β-SiC can act as a sink for the photogenerated holes because the valence band level of β-SiC is higher than the corresponding bands in CdS and TiO2. In addition, the level of the conduction band of TiO2 is lower than those of CdS and β-SiC, so TiO2 can act as the acceptor of the photogenerated electrons. Our results demonstrate that hole transfer and absorption in the visible light region lead to an effective hydrogen-production scheme.

Fern-like Nickel Cobalt Sulfide Electrocatalyst Prepared By Electrodeposition and Subsequent Sulfur Ion Exchange for Water Electrolysis

Recently, the attention on development of eco-friendly sustainable energy have been gradually increased, owing to the fossil fuel depletion and global warming. Among them, the utilization of hydrogen energy produced from water electrolysis is the one of the prominent methods to solve the problems due to the environmental-friendly characteristic of hydrogen energy. Representative study on water electrolysis is focusing on highly efficient and lower cost electrode development. It has been known that the Pt and IrO2 is the most activate catalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. However, they are very rare and expensive, indicating that the severe cost problem is still remained for hydrogen production from water electrolysis. To solve the problem many efforts have been conducted to the development of non-noble metal based catalysts as comparably active as Pt for HER and IrO2 for OER. In particular, the researches on transition metal compounds: M-X (M=Ni, Co, Fe and X= S or P) catalysts have been dominative during the past few years. In this study, we have fabricated the fern-like NixCoyS1-x-y catalyst for water electrolysis. Firstly, NixCoyO1-x-y was electrodeposited on the carbon paper (CP) by two-step galvanostatic deposition. The morphology and composition of fern-like NixCoyO1-x-y were controlled by varying deposition conditions. Then, annealing process was conducted to further oxidization of NixCoyO1-x-y. As a last step, sulfur ion exchange was carried out on the NixCoyO1-x-y by changing dipping time in sodium sulfide solution at 90 °C. Through field emission scanning electron microscope, energy dispersive spectroscopy and X-ray diffraction, formation of fern-like NixCoyS1-x-y was confirmed after the sufficient dipping time. Based on the electrochemical surface area, the intrinsic activity of NixCoyS1-x-y catalysts showed compositional dependence activity for water electrolysis.

Effects of Magnesium Sulfate and Sodium Sulfide on Fresh and Hardened Cement Mortar

In this study, the effects of magnesium sulfate and sodium sulfide on fresh and hardened cement mortar were examined. Water/cement ratios of 0.63 and 0.72 were used to produce two 410 kg/m3 dosed mortars. Various concentrations of sulfate salt solutions were prepared and used as mixing water. Solutions of magnesium sulfate and sodium sulfide and reference mortars were prepared with 1 l of mixing and drinking water, respectively. The mortars were produced in 26 (2 x 13) different mixtures. Eight samples were produced from each mixture for tests including shrinkage tests. Vibratory table experiments were used to determine the workable life of the mortars. The experiments were conducted by using a Vicat apparatus to determine the effects of the tested chemical substances on the setting duration. Six samples, which were prepared from each mixture, were held in water at a temperature of 20 ± 2°C until the test was started. The samples were aged for 7 d, 28 d, and 90 d, and two specimens from each aged sample were tested under bending and compression tests. The shrinkage tests involved measuring size changes of the two samples for duration of 90 d by holding the samples in a controlled environment at 21°C and 55%–65% humidity. Analysis was performed on the effects of sulfate salts on fresh and hardened concrete mixes. It was concluded from the results that magnesium sulfate had the most detrimental effect on the concrete mixes. In contrast, sodium sulfide increased the compressive strength of the concrete mix.

A selective process for extracting antimony from refractory gold ore

To avoid the adverse effects of antimony on the cyanide leaching process used for the recovery of gold from refractory gold ore, a cleaner production process was proposed that would selectively remove antimony as sodium pyroantimonate. The process included three steps: 1) leaching of antimony from the refractory gold ore with sodium sulfide solution; 2) pressure oxidation of the leaching solution containing sodium thioantimonite, transforming it to sodium pyroantimonate; and 3) concentration/crystallization to recover the sodium thiosulfate byproduct from the oxidized solution. The leaching recoveries of antimony, gold, and arsenic in the first step were 96.64%, 1.44%, and 0.41%, respectively. The precipitation ratio of antimony exceeded 99.80% during the second step. The synthesized sodium pyroantimonate product exhibited a regular tetragonal morphology. The purity of the sodium thiosulfate byproduct obtained during the third step reached 98.0%.

硫化ナトリウム溶液を用いる湖底堆積物中無機態リンの連続分画抽出/吸光光度定量法

硫化ナトリウム溶液を用いる湖底堆積物中無機態リンの連続分画抽出/吸光光度定量法

Structure and properties of nanoscale Ag2S/Ag heterostructure

Ag2S/Ag heteronanostructure has been produced by a simple one-stage chemical deposition from aqueous solutions of silver nitrate, sodium sulfide, and sodium citrate with the use of monochromatic light irradiation. The formation of Ag2S/Ag nanocomposite structures is confirmed by X-ray analysis, high-resolution electron microscopy, and energy dispersion analysis. It is established that in the contact layer between silver sulfide and silver, nonconductingα-Ag2S acanthite transforms into superionic β-Ag2S argentite under the action of external electric field. The scheme of the operation of a resistive switch based on an Ag2S/Ag heteronanostructure is proposed.

Treatment of Sulfidic Wastewater Using Iron Salts

Sulfides are often found to be present in the effluents generated from some chemical and petrochemical industries as well as from tanneries. Beyond a certain permissible limit, sulfides are generally toxic to living bodies. In the present work, solution of sodium sulfide was first mixed with \(\hbox {Fe}^{+2}/\hbox {Fe}^{+3}\) salt solutions in different ratios which resulted in precipitation of sulfide from the solution. This was followed by aeration of the residual solution. The maximum sulfide removal efficiency of the \(\hbox {Fe}^{+2}/\hbox {Fe}^{+3}\) treatment was approximately 70 %. However, upon aeration, the residual sulfide was eventually removed. The precipitate formed was characterized as ferrous sulfide, applying scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and X-ray power diffraction. The role of sulfide concentration, \(\hbox {Fe}^{+2}/\hbox {Fe}^{+3}\) ratio and temperature on the kinetics of sulfide removal from the aqueous solution was investigated. Effect of air flow rate during aeration of remaining sulfide was also investigated. The rate equation and activation energy for the precipitation reaction were calculated from the experimental results. The results of this study hold promise for effective treatment of sulfidic wastewater in chemical and allied industries.

Facile synthesis, structure, and properties of Ag2S/Ag heteronanostructure

Ag2S/Ag heteronanostructure has been produced by a simple one-stage chemical deposition from aqueous solutions of silver nitrate, sodium sulfide, and sodium citrate with the use of monochromatic light irradiation. For simultaneous synthesis of Ag2S and Ag nanoparticles, deposition has been performed from reaction mixtures with reduced sodium sulfide concentration. The size of Ag2S and Ag nanoparticles is 45–50 and 15–20 nm, respectively. It is established that in the contact layer between silver sulfide and silver, nonconducting α-Ag2S acanthite transforms into superionic β-Ag2S argentite under the action of external electric field. The scheme of the operation of a resistive switch based on an Ag2S/Ag heteronanostructure is proposed. The UV–Vis optical absorption spectra of colloidal solutions of Ag2S/Ag heteronanostructures have been studied.

Anti-Scoring Additives for Transmission Oils Based on C10 α−Olefin Fraction

Sulfur- and chlorine-containing products are obtained by reacting C10 α -olefins with sulfur monochloride. By sulfidation of the resulting reaction mixture with saturated aqueous sodium sulfide solution sulfur-containing products are synthesized. The optimum conditions are determined for synthesis of these products, which can be recommended as additives that improve tribological properties of lubricants. It is shown that specimens of mineral oils prepared by using the synthesized additives correspond in key performance properties to transmission oils TM-4, SAE, 80W-90, and API-type oil GL-4 with improved anti-scoring properties.

Ag2S silver sulfide nanoparticles and colloidal solutions: Synthesis and properties

Powders of silver sulfide Ag2S have been synthesized by hydrochemical bath deposition from aqueous solutions of silver nitrate and sodium sulfide in the presence of sodium citrate or EDTA-H2Na2. Colloidal non-toxic solutions of Ag2S nanoparticles have been prepared by chemical condensation method from the same aqueous solutions. The size of silver sulfide particles in deposited powders and colloidal solutions has been estimated with the use of X-ray diffraction, dynamic light scattering, transmission electron microscopy and Brunauer–Emmett–Teller techniques. By varying the ratio between the concentrations of reagents in the initial reaction mixtures it is possible to deposit Ag2S nanoparticles with pre-assigned average size ranging in the interval from about 500 nm down to about 40 nm. The average size of silver sulfide Ag2S nanoparticles in stable colloidal solutions is equal 10–20 nm. Special attention has been devoted to investigation of stability of synthesized colloidal solutions on the duration of their storage. The UV–Vis absorption spectra of colloidal solutions and optical reflectance of nanopowders of silver sulfide have been studied. Decreasing of average size of Ag2S nanoparticles from ∼500 nm down to ∼60 nm leads to increasing of energy band gap Eg from 0.88 to 1.21 eV. Studied colloidal solutions and nanopowders of silver sulfide possess the potential antibacterial activity.

Silver sulfide nanoparticles with a carbon-containing shell

Silver sulfide nanoparticles have been synthesized through chemical deposition from aqueous solutions of silver nitrate and sodium sulfide in the presence of sodium citrate as a complexing agent and stabilizer. The nanoparticles have a Ag2S core with a monoclinic crystal structure, covered with a carbon-containing citrate shell. Varying initial reactant concentrations, we can obtain core/shell nanoparticles with a tailored Ag2S core size and carbon-containing shell thickness.

Systematic synthesis of polyimide@inorganics core-shell microspheres via ion-exchange and interfacial reaction

Uniform and stable core-shell microspheres composed of a polyimide (PI) core and thin metal/oxide/sulphide shells were prepared by an interfacial reaction of metal-ion-doped polymeric cores in reduction or in the air or sodium sulphide solutions, respectively. The silver shells on polyimide microspheres were prepared by the introduction of silver ions into ion-exchangeable surface-modified polyimide, and subsequently an in situ reduction of the silver ions in solution. Oxides shells such as SnO2, Co3O4, NiO, CuO or ZnO were prepared by thermally treating the ion-doped microspheres in air, while amorphous sulphides shells such as CuS, ZnS, CoS or Ag2S were prepared by an interfacial reaction of metal-ion-doped microspheres in its corresponding sodium sulphide solutions. The adhesion properties between the copper sulphide and PI substrates are demonstrated superior. This simple strategy is promising in the fabrication of a whole range of inorganic shells on polyimide microspheres, which may offer tailor-designed multi-functionalities based on the distinctive species of these inorganic shells.

Performance of a Pilot-Scale Entrained-Flow Black Liquor Gasifier

Pilot-scale entrained flow gasification experiments were carried out at the 3 MWth LTU Green Fuels black liquor gasification (BLG) plant, using ∼140 tons of Kraft black liquor (BL) with a dry solids content of ∼72.5%. Comprehensive mass and energy balances were performed to quantify process performance under varying pressure, load, and oxygen/fuel ratio. Carbon conversion efficiency of the BLG process was 98.3%–99.2% and did not vary systematically in response to process changes. The unconverted carbon is almost exclusively present as dissolved organic carbon in the green liquor (GL) stream. GL is an aqueous solution of sodium carbonate and sodium sulfide used to recover the inorganic pulping chemicals present in BL for reuse in the pulp mill. A small fraction of syngas CO is converted to formate ions dissolved in GL through reaction with hydroxide ions. Unconverted carbon present in GL solids is insignificant. Syngas produced is subsequently upgraded to methanol and dimethyl ether (DME) in an integrated ...

Effects of foreign substances in cement mortar mixing water

This study examined the effects of magnesium sulfate and sodium sulfide on fresh and hardened cement mortar. Two 410 kg/m3 dosed mortars were produced (water/cement ratios of 0·63 and 0·72). Sulfate salt solutions were prepared in different concentrations and used as mixing water. Solutions of magnesium sulfate and sodium sulfide and reference mortars were prepared with 1 l of mixing and drinking water, respectively. Mortars were produced in 26 (2 × 13) different mixtures. From each mixture, eight samples were produced for shrinkage and other tests. The workable life of the mortars was determined by vibratory table experiments. Experiments were conducted using a Vicat apparatus to determine the effects of the tested chemical substances on setting duration. For each mixture, six samples were held in water at a temperature of 20 ± 2°C until the day of testing. Bending and compression tests were then performed on samples aged 7, 28 and 90 d (two samples per age). For shrinkage tests, size changes of the two samples were measured until the 90th day of holding in a controlled environment (21°C and 55%–65% humidity). The effects of sulfate salts on fresh and hardened concrete mixes were analysed. The results revealed that magnesium sulfate was the most detrimental, but also showed that sodium sulfide increased the compressive strength.

Optical Properties Research of Cadmium Sulphide Nanoparticles Received by the Interaction of the Reverse Emulsions Based on Sodium bis(2-ethilhexyl) Sulfosuccinate

By the inverted emulsions the sodium bis(2-ethilhexyl) sulfosuccinate, containing solutions of sodium sulfide and cadmium chloride, cadmium sulfide nanoparticles were synthesized. Based on UV-ranges of a transmission the band gap and the CdS particles’ sizes were determined. Two groups of particles’ depressiveness were identified. It is established that the order of the reversed emulsions coacervating with reagents changes the arrangement and properties of the formed colloidal particles. By the reverse emulsion coacervating with CdCl2 solution to emulsion with Na2S solution beside sulfide cadmium particles S8 molecules are formed. These molecules restrained CdS particles growth.

STRUCTURE AND PROPERTIES OF AG2S/AG SEMICONDUCTOR/METAL HETERONANOSTRUCTURE

Ag2S/Ag hetero-nanostructure has been produced by a simple one-stage chemical deposition from aqueous solutions of silver nitrate, sodium sulfide, and sodium citrate with the use of monochromatic light irradiation. For simultaneous synthesis of Ag2S and Ag nanoparticles, deposition has been performed from reaction mixtures with reduced sodium sulfide concentration. The formation of Ag2S/Ag nanocomposite structures is confirmed by X-ray analysis, high-resolution electron microscopy, energy dispersion analysis and dynamic light scattering methods. It is established that in the contact layer between silver sulfide and silver, non conducting α-Ag2S acanthite transforms into superionic β-Ag2S argentite under the action of external electric field. The scheme of the operation of a resistive switch based on an Ag2S/Ag hetero-nanostructure is proposed.

ВЗАИМОДЕЙСТВИЕ СУЛЬФИДА НАТРИЯ И ОКТАДЕКАНТИОЛА С СОЛЯМИ СМОЛЯНЫХ И НЕПРЕДЕЛЬНЫХ ЖИРНЫХ КИСЛОТ

In order to study attachment of hydrogen sulfide and methyl mercaptan to the double bonds of unsaturated fatty acids and rosin acids during kraft pulping and isolation The interaction sulfate soap and sodium oleate, sodium salts of resin acids from gum rosin aqueous-alkaline solution of sodium sulphide and 1-oktadekantiola at 160-165 °С. The formation of organic sulfides and thiols due to hydrogen sulfide and oktadekantiola connection respectively to the double bonds of the fatty acids and resin does not occur. It has been found that the washing-treatment of the reaction mass saline alkaline solution (sodium chloride + sodium hydroxide) containing copper metal after reaction with sodium sulfide or 1 oktadekantiolom prevents residual connection thiol and hydrogen sulfide to the double bonds of fatty and rosin acids by treatment 30% aqueous sulfuric acid. Maximum total sulfur content measured by two methods (energy dispersive x-ray fluorescence spectroscopy and UV-oxidation products of the high temperature), in this case in the final products of interaction of sodium oleate and sodium salts of rosin acids, sulfur compounds was 55 ppm. Known patterns may be used in the preparation of sulfate soap and tall oil and its fractions (fatty acids, rosin, pitch) with a low total sulfur content, which will expand the field of their application.

Replacement texture of cerussite reacted with aqueous sodium sulfide solution at temperatures from 130 °C to 170 °C

Replacement texture of cerussite reacted with aqueous sodium sulfide solution at temperatures from 130 °C to 170 °C