Showing papers on "Sodium sulfide published in 2017"

Statistical investigation of extraction parameters of keratin from chicken feather using Design-Expert

Abstract: Uncontrolled disposal of feathers from the poultry industry and slaughterhouses is environmentally undesirable The feathers are composed of approximately 90% of keratin which is an important ingredient of cosmetics, shampoos and hair treatment creams This study aimed to determine the optimum conditions for the extraction of keratin from chicken feathers The extraction of keratin using various reducing agents was studied using statistical experimental design In the extraction process, pH, temperature, ratio of reducing agents, mass of chicken feathers and incubation time were analyzed The keratin in the total extracted protein was purified by size exclusion chromatography, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and further characterized using amino acids profile analysis The surface morphology and chemical composition were studied by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis Sodium sulfide (Na2S) yielded 845% of keratin as compared to sodium hydroxide (438), urea mixture (506), mixture of sodium dodecyl sulfate (SDS) and sodium bisulfite (183) and a mixture of Na2S and sodium hydroxide (415%) under optimized conditions The optimum yield of keratin was achieved at 809 °C in 95 h with 005 M sodium sulfide using response surface methodology (RSM) Among the five parameters screened, pH was found not to be significant because the p value was greater than 005

Copper Sulfide Nanoparticle/Cellulose Composite Paper: Room-Temperature Green Fabrication for NIR Laser-Inducible Ablation of Pathogenic Microorganisms

Abstract: This work reports a new type of near-infrared (NIR) laser-inducible antimicrobial composite paper based on copper sulfide nanoparticles (CuS NPs). For the first time, a smart and green method to prepare CuS NPs was developed by taking advantage of the copper–amine complex as the copper source and sodium sulfide as the sulfur source at room temperature, in which a biopolymer xylan was used as the growth template and stabilizing agent. The obtained xylan/CuS NPs composites (CuS@Xylan NPs) were spherical and stable with an average diameter of ∼10 nm. CuS@Xylan NPs were subsequently allowed to penetrate into cellulose nanofiber (CNF) networks to prepare the composite paper. This CuS@Xylan NPs/CNF composite paper showed strong NIR laser-inducible antimicrobial effect on Escherichia coli, Bacillus subtilis, Stapylococcus aureus, and Aspergillus niger. In addition, the tensile strength, tear strength, and burst strength of the composite paper were improved likely due to the strong hydrogen bonding between xylan ...

Enhanced sulfidation xanthate flotation of malachite using ammonium ions as activator

Abstract: In this study, ammonium ion was used to enhance the sulfidation flotation of malachite. The effect of ammonium ion on the sulfidation flotation of malachite was investigated using microflotation test, inductively coupled plasma (ICP) analysis, zeta potential measurements, and scanning electron microscope analysis (SEM). The results of microflotation test show that the addition of sodium sulfide and ammonium sulfate resulted in better sulfidation than the addition of sodium sulfide alone. The results of ICP analysis indicate that the dissolution of enhanced sulfurized malachite surface is significantly decreased. Zeta potential measurements indicate that a smaller isoelectric point value and a large number of copper-sulfide films formed on the malachite surface by enhancing sulfidation resulted in a large amount of sodium butyl xanthate absorbed onto the enhanced sulfurized malachite surface. EDS semi-quantitative analysis and XPS analysis show that malachite was easily sulfurized by sodium sulfide with ammonium ion. These results show that the addition of ammonium ion plays a significant role in the sulfidation of malachite and results in improved flotation performance.

Sodium Sulfide-Promoted Thiophene-Annulations: Powerful Tools for Elaborating Organic Semiconducting Materials

Abstract: We describe herein facile thiophene annulation reactions promoted by sodium sulfide hydrate (Na2S·9H2O) for the synthesis of acene(di)thiophenes that can be further utilized as organic semiconductors or building blocks for the elaboration of semiconducting oligomers and polymers. Sodium sulfide hydrate is an efficient source of sulfur for both the aromatic nucleophilic substitution (SNAr) reaction and the nucleophilic hydrogen substitution (SNH) reaction to give a range of electron-donating acene(di)thiophenes and an electron-deficient naphtho[2,3-b:6,7-b′]dithiophene diimide (NDTI), respectively. We also describe organic semiconducting materials on the basis of these acene(di)thiophenes and their use in organic devices, such as organic field-effect transistors and organic photovoltaics, and demonstrate that synthetic evolution is one of the keys to promoting the field of organic semiconducting materials.

A Facile Surface Reconstruction Mechanism toward Better Electrochemical Performance of Li4Ti5O12 in Lithium-Ion Battery.

Abstract: Through a facile sodium sulfide (Na2S)-assisted hydrothermal treatment, clean and nondefective surfaces are constructed on micrometer-sized Li4Ti5O12 particles. The remarkable improvement of surface quality shows a higher first cycle Coulombic efficiency (≈95%), a significantly enhanced cycling performance, and a better rate capability in electrochemical measurements. A combined study of Raman spectroscopy and inductive coupled plasma emission spectroscopy reveals that the evolution of Li4Ti5O12 surface in a water-based hydrothermal environment is a hydrolysis-recrystallization process, which can introduce a new phase of anatase-TiO2. While, with a small amount of Na2S (0.004 mol L-1 at least), the spinel-Li4Ti5O12 phase is maintained without a second phase. During this process, the alkaline environment created by Na2S and the surface adsorption of the sulfur-containing group (HS- or S2-) can suppress the recrystallization of anatase-TiO2 and renew the particle surfaces. This finding gives a better understanding of the surface-property relationship on Li4Ti5O12 and guidance on preparation and modification of electrode material other than coating or doping.

A Facile Surface Reconstruction Mechanism toward Better Electrochemical Performance of Li 4 Ti 5 O 12 in Lithium-Ion Battery

Abstract: Through a facile sodium sulfide (Na2S)-assisted hydrothermal treatment, clean and nondefective surfaces are constructed on micrometer-sized Li4Ti5O12 particles. The remarkable improvement of surface quality shows a higher first cycle Coulombic efficiency (≈95%), a significantly enhanced cycling performance, and a better rate capability in electrochemical measurements. A combined study of Raman spectroscopy and inductive coupled plasma emission spectroscopy reveals that the evolution of Li4Ti5O12 surface in a water-based hydrothermal environment is a hydrolysis–recrystallization process, which can introduce a new phase of anatase-TiO2. While, with a small amount of Na2S (0.004 mol L−1 at least), the spinel-Li4Ti5O12 phase is maintained without a second phase. During this process, the alkaline environment created by Na2S and the surface adsorption of the sulfur-containing group (HS− or S2−) can suppress the recrystallization of anatase-TiO2 and renew the particle surfaces. This finding gives a better understanding of the surface–property relationship on Li4Ti5O12 and guidance on preparation and modification of electrode material other than coating or doping.

Chalcopyrite and pyrite floatabilities in the presence of sodium sulfide and sodium metabisulfite in a high pyritic copper complex ore

Abstract: One of the principal problems in flotation of copper complex ores is the presence of pyrite and copper-activated pyrite in moderately alkaline pHs. Misreported pyrite into copper concentrates dramatically declines copper grade and its recovery. In this study, the effect of sodium sulfide, sodium metabisulfite (SMBS), and their dosages (100, 200, 300, and 400 g/t) were investigated on chalcopyrite and pyrite floatabilities in a high pyritic copper sulfide ore. Furthermore, the role of particle size distribution (PSD) in three different levels (i.e., d70, d75, and d80 of passing 75 µm) was evaluated by a series of batch flotation experiments. It was revealed that using 200 g/t SMBS provides not only the highest and the lowest chalcopyrite and pyrite recoveries, but also the maximum and minimum copper and iron grades. Pyrite recovery was sharply increased by the addition of sodium sulfide in light of sodium sulfide-induced collectorless flotation; however, it showed a very weak effect on chalcopyrite...

Mechanism study on flotation separation of molybdenite from chalcocite using thioglycollic acid as depressant

Abstract: Effects of collectors (butyl xanthate (BX), O-isopropyl-N-sulfur ethyl carbamate (Z-200) and emulsified kerosene), dereagent (sodium sulfide) and depressant thioglycollic acid (TGA) on the flotation of chalcocite and molybdenite were investigated through flotation. The first principle theory was adopted to understand the difference of their surfaces and reaction between minerals and reagents. Results of flotation tests revealed that selectivity of emulsified kerosene is the best of three collectors in separation of chalcocite and molybdenite, though the others also display excellent collecting properties. Sodium sulfide can effectively remove collectors adsorbed on chalcocite surface, and TGA is an effective depressant of chalcocite at pH 8–9. Through first principle study, molybdenite displays relatively stronger covalence property while bonding interaction between copper atoms in chalcocite enhanced its ionicity. Bonding interaction is weaker in reaction of TGA and molybdenite, so it shows higher hydrophobicity and better flotability. Therefore, TGA is an effective inhibitor in the separation.

Study of the Effect of Sodium Sulfide as a Selective Depressor in the Separation of Chalcopyrite and Molybdenite

Abstract: Two kinds of collectors, sodium butyl xanthate and kerosene, and a depressor, sodium sulfide, were used in this research. The study applied flotation tests, pulp potential measurements, contact angle measurements, adsorption calculations, and Fourier Transform Infrared Spectroscopy (FTIR) analyses to demonstrate the correlation between reagents and minerals. For xanthate collectors, the best flotation responses of chalcopyrite and molybdenite were obtained at pH = 8, and, for kerosene, these were obtained at pH = 4. The flotation of molybdenite seemed to be less influenced by xanthate than by kerosene, while that of chalcopyrite showed the opposite. The optimum concentration of sodium sulfide for separation was 0.03 mol/L, which rejected 83% chalcopyrite and recovered 82% molybdenite in the single mineral flotation. Pulp potential measurements revealed that the dixanthogen and xanthate were decomposed and desorbed, respectively, from the mineral surface in a reducing environment. The contact angle measurement and adsorption calculation conformed to the flotation response, indicating that few functions of the xanthate and sodium sulfide on the molybdenite flotation were due to their low adsorption densities. The FTIR results further clarified that the xanthate ion was adsorbed on chalcopyrite by forming cuprous xanthate and dixanthogen; however, on molybdenite the adsorption product was only dixanthogen. After conditioning with sodium sulfide, the chalcopyrite surface became clean, but the molybdenite surface still retained slight peaks of dixanthogen. Meanwhile, the possible mechanism was expounded in this research.

Optimization of sodium sulfide treatment of rice straw to increase the enzymatic hydrolysis in bioethanol production

Abstract: The efficiency of sodium sulfide-assisted alkaline pulping for cellulose preparation from Oryza sativa L. rice straw in Vietnam for enzymatic saccharification was investigated. The response surface methodology was used for the determination of optimal technological parameters of alkaline pulping such as active alkali dosage, temperature and time. The optimal technological parameters were established to be active alkali dosage of 7%, treatment temperature of 100 °C and treatment time of 120 min. At these regimes, a maximal sugar yield of 51.8% (over dry rice straw) was obtained. It meant that the saccharification efficiency up to 97.1% could be achieved by using sodium sulfide-assisted alkaline pretreatment method. Addition of sodium sulfide into alkaline pretreatment resulted in higher sugar yield, higher level of depolymerization of lignin and less loss of cellulose. Moreover, liquid hydrolyzate after enzymatic hydrolysis was analyzed by HPLC to determine the compositions of sugar mixture. The fiber morphology in pretreated biomass solid was also revealed by SEM.

Na2S-influenced electrochemical migration of tin in a thin electrolyte layer containing chloride ions

Abstract: Sodium sulfide was used to prevent the formation of dendrites during the electrochemical migration of tin in chloride-containing thin electrolyte layers. This investigation was based on in situ electrochemical and optical techniques, as well as ex situ characterization. Results show that sodium sulfide can inhibit the electrochemical migration behavior of tin by precipitating tin ions on the anode side, and the inhibition effect strongly depends on concentration. The effects of an applied bias voltage and pH alterations in the system caused by Na2S hydrolysis were also studied. Proposals were made for the mechanisms involved to explain the role of sodium sulfide.

Solvent-Driven Iodine-Mediated Oxidative Strategies for the Synthesis of Bis(imidazo[1,2-a]pyridin-3-yl)sulfanes and Disulfanes.

Abstract: Two efficient iodine-mediated strategies, which are economical and one-pot, are described to access bis(imidazo[1,2-a]pyridin-3-yl)sulfanes and bis(imidazo[1,2-a]pyridin-3-yl)disulfanes in chloroform and acetic acid, respectively, by a direct oxidative homocoupling of imidazo-heterocycles using inexpensive sodium sulfide as a sulfur source. These strategies are scalable, and an array of substrates delivered their corresponding stable sulfur-bridged imidazo-heterocycles in excellent yields.

Analysis of Decreases in Systemic Arterial Pressure and Heart Rate in Response to the Hydrogen Sulfide Donor Sodium Sulfide

Abstract: H2S is a gasotransmitter capable of producing a decrease in mean arterial pressure and heart rate. The hypotensive and bradycardic effects of H2S can be dissociated, as shown with cardiac pacing ex...

Experimental Optimization and Modeling of Sodium Sulfide Production from H2S-Rich Off-Gas via Response Surface Methodology and Artificial Neural Network

Abstract: The existence of hydrogen sulfide (H2 S) in the gas effluents of oil, gas and petrochemical industries causes environmental pollution and equipment corrosion. These gas streams, called off-gas, have high H2 S concentration, which can be used to produce sodium sulfide (Na2 S) by H2 S reactive absorption. Na2 S has a wide variety of applications in chemical industries. In this study, the reactive absorption process was performed using a spray column. Response Surface Methodology (RSM) was applied to design and optimize experiments based on Central Composite Design (CCD). The individual and interactive effects of three independent operating conditions on the weight percent of the produced Na2 S (Y ) were investigated by RSM: initial NaOH concentration (10-20% w/w), scrubbing solution temperature (40-60 °C) and liquid-to-gas volumetric ratio (15 × 10−3 to 25 × 10−3 ). Furthermore, an Artificial Neural Network (ANN) model was used to predict Y . The results from RSM and ANN models were compared with experimental data by the regression analysis method. The optimum operating conditions specified by RSM resulted in Y of 15.5% at initial NaOH concentration of 19.3% w/w, scrubbing solution temperature of 40 °C and liquid-to-gas volumetric ratio of 24.6 × 10−3 v/v.

Preparation method of array-shaped multi-stage-structured cobalt nickel sulfide/foamed nickel supercapacitor electrode

Abstract: The invention discloses a preparation method of an array-shaped multi-stage-structured cobalt nickel sulfide/foamed nickel supercapacitor electrode, and belongs to the preparation technical field of the supercapacitor electrode. The technical scheme is characterized by comprising the steps of taking foamed nickel, cobalt nitrate and urea as the raw materials, performing a hydrothermal reaction in a hydrothermal reaction kettle at a temperature of 100-180 DEG C for 5-12h to deposit and grow a honeycomb-shaped multi-stage-structured cobalt zinc double hydroxide precursor assembled by ultra-thin lamination sheets in a crosslinking manner on a foamed nickel substrate; and next, immersing the precursor into a sodium sulfide solution to perform a secondary hydrothermal reaction at a temperature of 100-180 DEG C for 3-36h to convert the cobalt zinc double hydroxide precursor into sulfide to finally prepare the array-shaped multi-stage-structured cobalt nickel sulfide/foamed nickel supercapacitor electrode assembled by the ultra-thin lamination sheets in a crosslinking manner. The active electrode prepared in the invention can provide excellent electrode specific capacitance in an alkali electrolyte, has excellent rate capability and shows application potential in electrochemical energy storage.

Effects of Sodium Thiosulfate and Sodium Sulfide on the Corrosion Behavior of Carbon Steel in an MDEA-Based CO 2 Capture Process

Abstract: The corrosion behavior of carbon steel has been tested in the presence of sodium thiosulfate and sodium sulfide in an MDEA-based CO2 capture system using electrochemical methods, weight loss measurements and surface analysis. The results of electrochemical measurements revealed that both thiosulfate and sulfide showed corrosion resistance properties to carbon steel corrosion. The corrosion resistance for the system with thiosulfate increased with concentration, while the system with sulfide yielded better corrosion resistance to carbon steel at lower concentrations as increase in sulfide concentration decreased the corrosion resistance. The corrosion inhibition behaviors for both systems at 0.05 M salt concentrations were confirmed by weight loss measurement, and the solution with sodium sulfide exhibited a better inhibition with time.

Chemical treatments on the cuticle layer enhancing the uranium(VI) uptake from aqueous solution by amidoximated wool fibers

Abstract: Urea, sodium hydroxide and sodium sulfide were used to treat the cuticle layer of wool before graft copolymerization and amidoximation to enhance the uranium uptaking capacity of amidoximated wool fiber based adsorbent (Wool-g-AOs). The wool-g-AOs were used for recovery of U(VI) from aqueous solutions. The simulated nuclear industry effluent was used for investigating the selectivity and industrial applicability of Wool-g-AOs. The adsorption of uranium(VI) on Wool-g-AOs was pH dependent. The Langmuir model fitted well with the equilibrium data. Kinetic data were fitted well to pseudo second order model.

Stabilizing method for Cr-bearing waste slag or Cr polluted soil or combination of Cr waste slag and Cr polluted soil

Abstract: The invention discloses a stabilizing method for Cr-bearing waste slag or Cr polluted soil or a combination of the Cr waste slag and the Cr polluted soil. The stabilizing method includes the following steps that firstly, the pH value of the Cr-bearing waste slag or the Cr polluted soil is adjusted to 6 to 9; secondly, a reducing agent, an adsorbing agent and a crystal activating agent are added into a mixture obtained in the first step, the water content is adjusted to 20% to 40%, and even stirring is conducted; thirdly, a precipitating agent is added into a mixture obtained in the second step, even stirring is conducted, and airtight curing is conducted; in the second step, the reducing agent is one or a combination of ferrous sulfide, sodium metabisulfite and sodium hydrosulfite, the adsorbing agent is clay minerals, and the crystal activating agent is silicon dioxide; and in the third step, the precipitating agent is one or a combination of sodium sulfide and calcium polysulfides. By means of the stabilizing method, a curing agent does not need to be added, operation is simple, the capacity increasing rate is small, cost can be greatly reduced, and long-term stability is good.