Showing papers on "Sodium sulfide published in 2014"

Synthesis and characterization of magnetic copper ferrite nanoparticles and their catalytic performance in one-pot odorless carbon-sulfur bond formation reactions

Abstract: In this article, we have introduced catalytic application of copper ferrite nanoparticles (CuFe 2 O 4 ) for one-pot odorless production of aryl alkyl thioethers using thiourea and alkyl bromides in wet polyethylene glycol as a green solvent. The catalyst was also successfully applied for one-pot synthesis of symmetrical diaryl trithiocarbonates via the reaction of sodium sulfide, carbon disulfide and aryl iodides under heterogeneous reaction condition. Magnetic copper ferrite nanoparticles were synthesized using iron (III) chloride and copper (II) chloride, and characterized using XRD, FT-IR, AAS, and TEM analysis. The catalyst was recycled using simple magnetic separation and reused for the five consecutive runs in the reaction of iodobenzene, thiourea and benzyl bromide without appreciable loss of activity.

Low-temperature and one-pot synthesis of sulfurized graphene nanosheets via in situ doping and their superior electrocatalytic activity for oxygen reduction reaction

Abstract: The chemical doping of foreign atoms and functional moieties is a significant strategy for tailoring the electronic properties and enhancing the catalytic ability of graphene. However, the general approaches to the synthesis of heteroatom-doped graphene often involve chemical vapor deposition (CVD) and/or thermal annealing performed at high temperature under gas phases, which require special instruments and tedious process. In this study, we have developed a low temperature, economical, and facile one-pot hydrothermal method to synthesise sulfur-doped reduced graphene oxide (S-RGO) nanosheets, in which the sodium sulfide (Na2S) was employed not only as a sulfur source but also as a reductant to reduce the graphene oxide (GO) simultaneously with sulfur (S) being in situ doped into graphene frameworks. The as-prepared S-RGO has a high S content (4.19 at%), as well as high-quality sulfurated species (mainly as C–S–C–), and possesses numerous open edge sites and defects on its surface, which are beneficial for the improved ORR catalytic activity. Electrochemical characterizations clearly demonstrated the excellent electrical conductivity and superior electrocatalytic activity of S-RGO for oxygen reduction reaction (ORR), coupled with considerably enhanced stability and methanol tolerance compared to the commercial Pt/C catalyst. The present low temperature and one-pot approach provides the possibility for the synthesis of S-RGO at the Gram-scale for its application in electronic nanodevices and electrode materials for fuel cells.

Biosynthesis of CdS nanoparticles in banana peel extract.

Abstract: Cadmium sulfide (CdS) nanoparticles (NPs) were synthesized by using banana peel extract as a convenient, non-toxic, eco-friendly 'green' capping agent. Cadmium nitrate and sodium sulfide are main reagents. A variety of CdS NPs are prepared through changing reaction conditions (banana extracts, the amount of banana peel extract, solution pH, concentration and reactive temperature). The prepared CdS colloid displays strong fluorescence spectrum. X-ray diffraction analysis demonstrates the successful formation of CdS NPs. Fourier transform infra-red (FTIR) spectrogram indicates the involvement of carboxyl, amine and hydroxyl groups in the formation of CdS NPs. Transmission electron microscope (TEM) result reveals that the average size of the NPs is around 1.48 nm.

Transformation and destabilization of graphene oxide in reducing aqueous solutions containing sulfide

Abstract: The colloidal stability of carbon nanomaterials is a key factor controlling their fate and bioavailability in natural aquatic systems. The authors report that graphene oxide nanoparticles could be destabilized in reducing aqueous solutions containing a low concentration (0.5 mM) of sulfide, a naturally occurring reductant. Spectroscopic characterization using combined X-ray photoelectron, Fourier-transform infrared, X-ray diffraction, and Raman analyses revealed that the surface oxygen-containing groups (mainly epoxy groups) of graphene oxide were significantly reduced after reacting with sodium sulfide. The destabilization of graphene oxide was likely caused by the enhanced surface hydrophobicity of the reduced graphene oxide, whereas electrostatic repulsion played a minimal role. Solution pH was found to affect both the deoxygenation process and the aggregation behavior of graphene oxide. Coexisting humic acid reduced the reaction efficiency and stabilized graphene oxide through steric hindrance. These findings suggest for the first time that the colloidal behavior of carbon nanomaterials might change drastically when they enter natural reducing environments containing sulfide such as anaerobic aquifers and sediments.

Electrochemical Preparation and Thermal Characterization of Copper Sulfide Nanoparticles

Abstract: CuS nanoparticles in different sizes and shapes were synthesized by electrolysis of a copper plate as anode in sodium sulfide aqueous solutions. The results revealed that size and shape of the product could be tuned by the reaction parameters including electrolysis voltage and sulfide ion concentration as reactant. The results showed that the size of CuS nanoparticles decreased with increasing electrolysis voltage from 2 to 13 V. Meanwhile, the size and shape of the prepared CuS nanoparticles were found to be dependent on the concentration of sulfide solution used. Also, the results of characterization of the prepared CuS nanoparticles were reported.

Dual effects of sodium sulfide on the flotation behavior of chalcopyrite: I. Effect of pulp potential

Abstract: This study explores the flotation behavior of chalcopyrite in the presence of different concentrations of sodium sulfide (Na2S·9H2O) at pH 12 under controlled potential conditions. It was observed that the flotation of chalcopyrite is not depressed completely when the pulp potential is low, even at high concentrations of sodium sulfide, i.e., 10−1–10−2 mol/L. However, a partial and controlled oxidation of pulp does enhance the effectiveness of sodium sulfide on the depression of chalcopyrite. Characterization of the chalcopyrite particle surface by X-ray photoelectron spectroscopy allowed the identification of hydrophilic and hydrophobic surface species, which are responsible for the depression and flotation of chalcopyrite. Changes in pulp potential were found to be an effective float controlling parameter, by which Na2S can be used to initiate or depress the flotation behavior of chalcopyrite.

Synthesis and characterization of novel poly(phenylene sulfide) containing a chromophore in the main chain

Abstract: A kind of novel poly(phenylene sulfide)s (PPSs) containing a chromophore group were synthesized by the reaction of dihalogenated monomer and sodium sulfide (Na2S.xH2O) via nucleophilic substitution polymerization under high pressure. The polymers were characterized by Fourier transform infrared spectroscopy, ultraviolet spectroscopy, fluorescence spectroscopy, XRD, DSC, TGA, mechanical testing and dissolvability experiments. The intrinsic viscosity of the polymers obtained with optimum synthesis conditions was 0.22 − 0.38 dl g−1 (measured in 1-chloronaphthalene at 208 °C). These polymers were found to have good thermal performance with a glass transition temperature (Tg) of 90.5 − 94.6 °C and initial degradation temperature (Td) of 475–489 °C, showing improved thermal properties compared with homo-PPS. At the same time the resultant resins had a high tensile strength of 67.5 − 74.1 MPa and compressive strength of 70.7 − 85.4 MPa. Additionally, these polymers exhibited a weak UV − visible reflectivity minimum at 450–570 nm, and the fluorescence spectra of the polymers showed maximum emission around nearly 370 nm. Also they showed excellent chemical resistance and another special property − bright shiny colors changed into different colors in acid solution. © 2014 Society of Chemical Industry

Synthesis of metastable wurtzite CuInS2 nanocrystals and films from aqueous solution

Abstract: For the first time, metastable wurtzite CuInS2 nanocrystals and films were successfully synthesized from aqueous solution under atmospheric conditions. The CuInS2 nanocrystals were prepared by stirring and reflux of a metal salt and sodium sulfide in aqueous solution containing thioglycolic acid as a stabilizer. The good absorption in the visible light region may find interesting application in solar cells. The I–V curve indicated that the wurtzite CuInS2 NCs favored the generation of photoinduced carrier and electronic transmission. The proposed synthesis strategy may be used as a general process for the synthesis of hydrophilic chalcogenide semiconductor NCs and is scalable for commercial production with minimal environmental impact.

Synthesis of a stable colloidal solution of PbS nanoparticles

Abstract: A method has been proposed for the synthesis of stable colloidal solutions of lead sulfide nanoparticles from aqueous lead acetate and sodium sulfide solutions. The citrate ion and ethylenediaminetetraacetic acid were used as complexing agents to stabilize the solution. The solutions obtained were shown to remain stable at room temperature for at least 30 days from the instant of synthesis, depending on the initial reactant concentration. According to X-ray diffraction and dynamic light scattering data, the stability and coagulation of the nanoparticles in solution were influenced by the lead and sulfur concentration, the presence of complexing agents, and the quantitative relation between the lead and complexing agent ions in solution. Optical absorption measurements for the colloidal PbS nanoparticle solutions showed that their absorbance was a nonlinear function of reactant concentration.

Direct observation of liquid pre-crystallization intermediates during the reduction of aqueous tetrachloroaurate by sulfide ions

Abstract: Phenomena preceding precipitation of gold(I) sulfide in the reaction of aqueous tetrachloroauric acid with sodium sulfide have been studied applying several time-resolved in situ techniques. As can be deduced from UV-vis absorption spectroscopy, soluble species (“pre-nucleation clusters”) emerge within several seconds and slightly change with time; the spectra, along with the previous data for the immobilized products, are indicative of disordered matter with Au(I)–S bonding and the gap of about 1.5 eV. In situ tapping-mode atomic force microscopy (AFM) directly imaged “soft” droplet-like species from 20–50 nm to about 200 nm in the lateral size and the continuous film condensed on the highly oriented pyrolytic graphite (HOPG) support. Small-angle X-ray scattering (SAXS) revealed quasi-particles (“liquid clusters”) growing to about 12 nm for 30 min, and slowly afterwards. Dynamic light scattering (DLS) was preferentially due to the larger species, although the liquid clusters within 20 nm comprise more than 80% of the total volume of the fluid products. The entities, which exist in solution for many hours before sudden gold sulfide sedimentation, are considered as “dense liquid” intermediates involved in a non-classical nucleation pathway.

Preparation of nanocrystalline lead sulfide powder with controlled particles size

Abstract: Lead sulfide nanopowders have been prepared from aqueous solutions of lead acetate and sodium sulfide in the presence of sodium ethylenediaminetetraacetate or citrate. From microscopy and X-ray diffraction data purity and size of the formed nanoparticles are determined by the reagents concentrations, presence and nature of the complexing ligand, and the ratio of lead ions concentration to that of the ligand. PbS nanoparticles of the predefined size ranged from 5 to 55 nm can be prepared by controlled hydrochemical precipitation.

Treatment process for chemical nickel plating waste liquid in circuit board industry

Abstract: The invention provides a treatment process for a chemical nickel plating waste liquid in the circuit board industry. The treatment process comprises the following steps: pumping the chemical nickel plating waste liquid in the circuit board industry into a reaction tank; sequentially adding sulfuric acid for acidifying; adding ferrous sulfate and hydrogen peroxide for Fenton oxidation complexation; adjusting the pH by sodium hydroxide; adding sodium sulfide for a coagu-flocculation reaction; finally, adding PAM until suspended solids are just flocculently separated; after acidification, advanced oxidation complexation, and flocculation, filter-pressing all the waste liquid by a plate-frame; collecting the filtrate and regulating the pH; and sequentially carrying out sand filtering and resin adsorption and discharging after reaching standard level. The treatment process provided by the invention can be used for effectively treating the chemical nickel plating waste liquid in the circuit board industry, so that the treatment cost and the standard-reaching difficulty of the waste liquid in an enterprise are reduced.

Floatation depressant and methods for preparing and using depressing agent

Abstract: The invention relates to a floatation depressant for obtaining molybdenum concentrate and copper concentrate by mineral separation, particularly by separation of copper-molybdenum mixed concentrate, and methods for preparing and using the floatation depressant. The floatation depressant is characterized by being an organic liquid agent obtained through chemical reaction by using mercaptoacetic acid, gallic acid and sodium hydroxide as raw materials. The floatation depressant is the organic liquid agent obtained through the chemical reaction of pyrogallic acid, the mercaptoacetic acid and the sodium hydroxide, and can be used for effectively depressing primary and secondary copper sulfide ores such as copper pyrite and chalcocite, and the copper-molybdenum mixed concentrate can be effectively separated. The defects of large usage of common sodium sulfide, severe operation environment and serious pollution are overcome, and the floatation depressant has the advantages of convenience in addition, safety in use and the like. An effective method which is small in agent usage, convenient to use and low in environmental pollution is provided for the separation of molybdenum copper sulfide mixed concentrate.

Beneficiation method of high grade scheelite ore

Abstract: The present invent discloses a method of selecting low-grade scheelite by floatation using sodium sulfide. The method disclosed herein is characterized by including the steps of: mixing fine minerals with water to prepare pulp; sorting scheelite from the pulp by floatation to collect rougher concentrate of scheelite; sorting the rougher concentrate of scheelite by floatation to obtain cleaner concentrate of scheelite; and treating the pulp with an alkaline solution to adjust the alkaline hydrogen ion concentration of the pulp to a predetermined concentration, wherein sodium sulfide is added during obtaining the rougher and cleaner concentrates so as to increase the alkaline hydrogen ion concentration of the pulp.

Dual effects of sodium sulfide on the flotation behavior of chalcopyrite： I. Effect of pulp potential

Abstract: 这研究在 12 在控制潜力下面调节的 pH 面对钠硫化物(Na2S 路 9 H2O ) 的不同集中探索黄铜矿的筹款行为。肉潜力什么时候是低的，被观察黄铜矿的筹款完全是不沮丧的，甚至在钠硫化物的高集中，即， 10 ? 1 鈥 ? 0 ? 2 mol/L。然而，肉的部分、控制的氧化确实在黄铜矿的消沉上提高钠硫化物的有效性。由 X 光检查光电子光谱学的黄铜矿粒子表面的描述允许吸水、恐水病的表面种类的鉴定，它为黄铜矿的消沉和筹款负责。在肉潜力的变化被发现是控制参数， Na2S 能被用来开始或压抑黄铜矿的筹款行为的有效漂流。

P4S10 and Na2S-mediated novel annulation routes to c-fused thiophenes

Abstract: Two efficient hetero-annulation protocols have been developed for the synthesis of stable substituted c-fused thiophene derivatives with moderate to high yield. 3-(2-formyl-phenyl)-acrylic acid esters afforded benzo[c]thiophenes in the presence of phosphorus pentasulfide in refluxing benzene while 3-(2-formyl-cycloalkenyl)α,β-unsaturated esters resulted in the formation of c-fused thiophene derivatives when reacted with sodium sulfide in refluxing tetrahydrofuran.

Auxiliary-addition-free polyphenylene sulfide resin industrial synthetic process

Abstract: The invention discloses auxiliary-addition-free polyphenylene sulfide resin industrial synthetic process. The formula of raw materials required in the auxiliary-addition-free polyphenylene sulfide resin industrial synthetic process is as follows: the mole ratio of sodium sulfide to sodium hydroxide to santochlor to N-methyl-2-pyrrolidinone is 0.93-1.15 to 1.00-1.28 to 1.98-2.98 to 1.18 to 1.48. The industrial synthetic process mainly comprises the following steps: firstly, in a sodium hydrosulfide dehydration treatment stage, a pipeline filter is adopted to filtrate a sodium hydrosulfide solution to treat mechanical impurities in the solution, then a sodium hydroxide solution with the concentration 84 mol percent is added in the formula for chemical treatment on the sodium hydrosulfide; secondly, in the condensation polymerization stage, anaerobic deionized water is added to further appropriately adjust the molecular weight and molecular weight distribution coefficient of synthesized polyphenylene sulfide resin; thirdly, deionized water is adopted for repeatedly scrubbing for 3 to 6 times, and finally, the target product of the auxiliary-addition-free polyphenylene sulfide resin industrial synthetic process provided by the invention is obtained. The resin in the obtained product of the auxiliary-addition-free polyphenylene sulfide resin industrial synthetic process is low in polydispersity index and high in oxygen index, and has an excellent electrical insulation property.

Electrochemical Synthesis and Characterization of Zinc Sulfide Nanoparticles

Abstract: Electrosynthesis process has been used for preparation of zinc sulfide nanoparticles. Zinc sulfide nanoparticles in different size and shapes were electrodeposited by electrolysis of zinc plate as anode in sodium sulfide solution. Effects of several reaction variables, such as electrolysis voltage, sulfide ion concentration as reactant, stirring rate of electrolyte solution and temperature on particle size of prepared zinc sulfide were investigated. The significance of these parameters in tuning the size of zinc sulfide particles was quantitatively evaluated by analysis of variance (ANOVA). Also, optimum conditions for synthesis of zinc sulfide nanoparticles via electrosynthesis reaction were proposed. The structure and composition of prepared nanoparticles under optimum condition was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-Vis spectrophotometry techniques.