Sodium Sulfide Research Articles

Sulfide Immobilization: Investigating the Impact of a Protective Sulfide-Bearing Layer Formed by Siderite (FeCO3)

Sulfate-rich wastewater poses ecological hazards to freshwater ecosystems, and sulfate is highly regulated in many Minnesota lakes. Biological sulfate reduction results in the reduction of sulfate to sulfide, and this process is used to remediate acid mine drainage. Theoretically, the aqueous sulfide can be immobilized into a solid-phase material and removed from the aqueous system. This study focuses on sulfide immobilization using iron-bearing waste minerals. Specifically, the extent of reaction of siderite (FeCO3), an abundant ferrous mineral in some mining wastes, with sulfide was studied. Mildly acidic batch reactors containing powdered siderite were consecutively injected with a sodium sulfide solution. Solid reaction products were identified and characterized using powder X-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Mackinawite (FeS) appeared to be the most abundant product, with greigite (Fe3S4) also detected. Results reveal that the immobilization capacity of sulfide by siderite is limited by the concentration of the Fe2+(aq) presented in the system immediately before the initial sulfide exposure as the Fe2+(aq) levels are not replenished after sulfidation. These results improve our understanding of the sulfidation of siderite and provide insight to improve the viability of using siderite-containing mining waste rock in a sulfate remediation technology.

First-Principles Investigation on Multi-Sodium Sulfide and Sodium Sulfide Clusters in Sodium-Sulfide Batteries

Room temperature sodium-sulfur batteries are expected to be widely used in large energy storage and power batteries due to their high energy density, abundant resources, and low price. However, shuttle effect of polysulfide, low reactivity of the end product, low activity of sodium sulfide, and electrode swelling are the main challenges. In order to improve the low sodium sulfide reaction performance and electrode swelling, the volume swelling of the final product sodium sulfide can be well controlled by using sodium sulfide directly as the cathode, and a special cathode structure was developed to overcome the “inert” problem of Na2S. Nevertheless, the structure, relative stability and electronic properties of (Na2S)n clusters are still uncertain so far, which is a necessary prerequisite for optimizing their properties and understanding their partitioning processes. In this paper, theoretical calculations of (Na2S)n clusters were performed to investigate the catalytic decomposition of sodium sulfide by mono-atomic catalysts, giving the energy distribution of sodium ions diffusing over FeN4 and FeN2. Together, these calculations confirm the high coordination design of mono-atomic Fe–N–C catalysts with high sulfur affinity and catalytic activity. Our work is an important step toward understanding (Na2S)n clusters and improving the performance of Na–S cells.

Preparing and properties of films with Ag2S quantum dots in a polyvinyl alcohol matrix

Stable colloidal solutions of Ag2S quantum dots with a size of 2–3 to 28–30 nm were synthesized by a hydrochemical deposition in low-concentration water solutions of silver nitrate, sodium sulfide, and sodium citrate. A large absolute value of the measured zeta potential of colloidal solutions, a small change in the size of quantum dots and zeta potential during long-term storage of solutions for 1000 days after synthesis indicate their high temporal stability. The synthesized colloidal solutions were dispersed in a solution of polyvinyl alcohol. The resulting films of Ag2S quantum dots in a PVA matrix are flexible and have a thickness of no more than 0.03 mm. The use of the PVA matrix to prepare films with Ag2S quantum dots promotes the preservation and increase in the stability of colloidal particles due to their fixation in the polymer matrix. For the first time, the optical properties of Ag2S quantum dots of different sizes in PVA films were determined. Decreasing the size of Ag2S quantum dots to 2.6 nm leads to an increase in the band gap of silver sulfide to 1.85 eV. It is shown that repeated bending of the films has practically no effect on the Eg value of Ag2S quantum dots.

In Situ Gravimetric Probing of Copper Sulfide Formation on the Counter Electrode for Quantum Dot Sensitized Solar Cells

Copper sulfide is a classical counter electrode (CE) catalytic material for the high catalytic activity of polysulfide in quantum dot-sensitized solar cells (QDSSCs). Actually, copper sulfide is a complicated compound. Different preparation methods will lead to the difference in the morphology and structure of copper sulfide, which has a profound impact on its catalytic activity. However, the formation mechanism and electrochemical properties of copper sulfide are rarely reported in the field of QDSSCs. Herein, we report an approach to obtain a high-stability counter electrode material by the electrochemical synthesis in sodium sulfide solution. The in situ electrochemical quartz crystal microbalance (EQCM) method was also employed to reveal the detailed transformation mechanism of copper vulcanized into copper sulfide during cyclic voltammetry in sodium sulfide solution. According to the calculation results of mpe theory, the formation of copper sulfide is accompanied by side reactions such as the conversion of polysulfide ions and water oxidation. Copper sulfide was proven to be a copper-rich phase by X-ray photoelectron spectroscopy (XPS) and other characterization methods. The photoconversion and stability of QDSSCs were studied using CdSe QD as the sensitizing material. The results show that the performance of copper sulfide prepared by this working method is better than the CE prepared by chemical bath deposition (CBD), and the replicability of photoelectric conversion efficiency (PCE) is better than CBD-CE. This work has theoretical significance to reveal the complex formation mechanism, electrochemical process mechanism, and working mechanism of copper sulfide in QDSSCs.

Reversible Sodium–Sulfur Batteries Enabled by a Synergistic Dual-Additive Design

We demonstrate here that a combination of bismuth triflate and 1,3,2-dioxathiolane 2,2-dioxide additives in a conventional ether-based electrolyte enables Na metal to cycle with a high Coulombic efficiency of above 99% and completely suppresses the dissolution of sodium polysulfides. Bismuth triflate enables a facile dissolution of sodium triflate based on a salt-in mechanism, which increases the sodium salt concentration and effectively prevents the decomposition of the solvent and additive. This process also facilitates the formation of an anion-derived inorganic solid electrolyte interphase. Additionally, the 1,3,2-dioxathiolane 2,2-dioxide additive spontaneously reacts with sodium sulfide to form a thiosulfate-based robust cathode–electrolyte interphase on a sulfurized polyacrylonitrile (SPAN) cathode. The full cell operated under a practical cell configuration attains a capacity retention of 79% for 150 cycles with a capacity of 535 mAh/g of SPAN. This work reveals the synergistic effects of commonly used additives on stabilizing the aggressive sodium–sulfur chemistry and opens great opportunities for practical applications.

Reduction-Responsive Supramolecular Sheets for Selective Regulation of Facultative Anaerobe Agglutination.

Stimuli-responsive supramolecular materials have promising biological applications because of their ability to rapidly undergo significant structural changes in response to diverse stimuli. Herein, we report supramolecular sheets assembled via charge-transfer interactions between the pyrene moiety of a d-mannose-containing amphiphile and 7,7,8,8-tetracyanoquinodimethane (TCNQ). The supramolecular sheets showed reduction-responsive behavior, in which their disassembly was triggered by the reduction of TCNQ by sodium sulfide. In an anaerobic environment, the sheet structure remained intact and the exposed d-mannose moieties induced the agglutination of facultative anaerobes, thereby inhibiting bacterial growth. In contrast, in an aerobic environment, the reduction of TCNQ by the hydrogen sulfide generated by facultative anaerobes caused sheet disassembly. This enabled continuous bacterial growth, because the collapsed sheets could not induce agglutination. Thus, this study presents a novel supramolecular material for the selective regulation of facultative anaerobe growth according to the external environment. This article is protected by copyright. All rights reserved.

Flotation Mechanism of Sphalerite by Sulfuration–Amine Method

Sphalerite is a common sulfide mineral, and xanthate is usually used as the collector of sphalerite flotation. In order to realize the simultaneous flotation of sphalerite- and zinc-containing oxide ores, in this paper, dodecylamine was used as the collector and sodium sulfide as the regulator to explore the flotation behavior of sphalerite in a sulfuration–amine system through single mineral flotation tests, and several analytical methods, including contact angle measurement, adsorption capacity test, FT-IR, and XPS, were employed to discuss the interaction mechanism of dodecylamine on the surface of sphalerite. The results confirm that dodecylamine had a strong collecting effect on sphalerite throughout almost the entire pH range, and the flotation recovery increased with the increase in pH, reaching 86.81% at pH 12. It was found that the effect of sodium sulfide on the floatability of sphalerite was relatively weak, and a weak activation effect, of about 2% improved recovery, was achieved. The results of the mechanism analysis further show that dodecylamine underwent both physical adsorption and chemical adsorption on the surface of sphalerite, and the physical adsorption was enhanced with the increase in pH. The above findings provide evidence for the simultaneous flotation of zinc-containing sulfide-oxide mixed minerals.

Fourier transform infrared studies of gel polymer electrolyte based on poly(acrylamide-co-acrylic acid) – Ethylene carbonate incorporated with water-soluble sodium sulfide

The incorporation of plasticizer to a solid polymer electrolyte have shown high conductivity, good thermal and chemical stabilities, long life and reduced costs. The improved conductivity is mainly contributed by higher ion diffusion coefficient and better ion mobility. However, little is known about the possible molecular interactions between plasticizer, polymer host and salt, particularly in explaining the mechanism pertaining to ion transport in the gel polymer electrolytes (GPEs). A flexible GPE based on poly(acrylamide-co-acrylic acid) (PAAm-PAA), ethylene carbonate (EC) and water-soluble sodium sulfide (Na2S) was developed. PAAm-PAA and Na2S are incorporated as the polymer backbone and the source of charge carriers, respectively, and EC acts as the plasticizer of the system. When 0.4 wt% of EC was added to PAAm-PAA-Na2S GPE, the ionic conductivity of polymer electrolytes increased from 5.11 × 10−2 S cm−1 to 6.92 × 10−2 S cm−1. The possible molecular interactions between PAAm-PAA, Na2S and EC and their correlation with ionic conductivity were investigated by Fourier transform infrared (FTIR) spectroscopy. Infrared spectroscopy showed that the intensities of the amide (CO, C–N), carboxylate (COO−) and sulfate (SO42−) bands increased with the addition of EC, and the position of the asymmetric bending (v4) of SO42− band down shifted from 677 cm−1 to 667 cm−1. These findings, the changes in shape, intensity, and position of the PAAm-PAA-Na2S-EC GPE, suggest a dipole-dipole interaction between (i) PAAm-PAA and distilled water, (ii) PAAm-PAA and EC and (iii) EC and distilled water. On the other hand, ion-dipoles interactions may occur between (i) Na+ cation and distilled water, (ii) Na+ cation and PAAm-PAA and (iii) Na+ cation and EC. It can be concluded that EC interacts with both PAAm-PAA and Na2S, and EC-Na+ complexes also appear in PAAm-PAA-Na2S-EC GPE. The increase in the conductivity of GPE is attributed to the high ion diffusion coefficient and mobility, which is attributed to the presence of EC.

Innentitelbild: Covalent Scrambling in Porous Polyarylthioethers through a Stepwise SNAr for Tunable Bandgap and Porosity (Angew. Chem. 28/2023)

A scrambled but selective polycondensation reaction introduced the simplest route to generate porous poly(aryl thioether)s. Through a multi-para nucleophilic substitution of perfluoroaromatic compounds with sodium sulfide, temperature-dependent formation of thioether linkages leads to stepwise transition of the polymers into network structures with controllable porosity and bandgap, as reported by Jeehye Byun, Sheng Li, Cafer T. Yavuz et al. in their Research Article (e202304378).

Inside Cover: Covalent Scrambling in Porous Polyarylthioethers through a Stepwise SNAr for Tunable Bandgap and Porosity (Angew. Chem. Int. Ed. 28/2023)

A scrambled but selective polycondensation reaction introduced the simplest route to generate porous poly(aryl thioether)s. Through a multi-para nucleophilic substitution of perfluoroaromatic compounds with sodium sulfide, temperature-dependent formation of thioether linkages leads to stepwise transition of the polymers into network structures with controllable porosity and bandgap, as reported by Jeehye Byun, Sheng Li, Cafer T. Yavuz et al. in their Research Article (e202304378).

Covalent Scrambling in Porous Polyarylthioethers through a Stepwise SNAr for Tunable Bandgap and Porosity

AbstractPorous poly(aryl thioether)s offer stability and electronic tunability by robust sulfur‐aryl conjugated architecture, but synthetic access is hindered due to limited control over the nucleophilic nature of sulfides and the air sensitivity of aromatic thiols. Here, we report a simple, one‐pot, inexpensive, regioselective synthesis of highly porous poly(aryl thioether)s through polycondensation of perfluoroaromatic compounds with sodium sulfide. The unprecedented temperature‐dependent para‐directing formation of thioether linkages leads to a stepwise transition of the polymer extension into a network, thereby allowing fine control of the porosity and optical band gaps. The obtained porous organic polymers with ultra‐microporosity (<1 nm) and sulfur as the surface functional groups show size‐dependent separation of organic micropollutants and selective removal of mercury ions from water. Our findings offer easy access to poly(aryl thioether)s with accessible sulfur functionalities and higher complexity, which will help in realizing advanced synthetic designs in applications such as adsorption, (photo)catalysis, and (opto)electronics.

Covalent Scrambling in Porous Polyarylthioethers through a Stepwise SN Ar for Tunable Bandgap and Porosity.

Porous poly(aryl thioether)s offer stability and electronic tunability by robust sulfur-aryl conjugated architecture, but synthetic access is hindered due to limited control over the nucleophilic nature of sulfides and the air sensitivity of aromatic thiols. Here, we report a simple, one-pot, inexpensive, regioselective synthesis of highly porous poly(aryl thioether)s through polycondensation of perfluoroaromatic compounds with sodium sulfide. The unprecedented temperature-dependent para-directing formation of thioether linkages leads to a stepwise transition of the polymer extension into a network, thereby allowing fine control of the porosity and optical band gaps. The obtained porous organic polymers with ultra-microporosity (<1 nm) and sulfur as the surface functional groups show size-dependent separation of organic micropollutants and selective removal of mercury ions from water. Our findings offer easy access to poly(aryl thioether)s with accessible sulfur functionalities and higher complexity, which will help in realizing advanced synthetic designs in applications such as adsorption, (photo)catalysis, and (opto)electronics.

Optimization of eucalyptus cellulose fiber using response surface methodology: Effects of sulfur content and refining time on the mechanical characteristics of paper pulp

The purpose of this study was to examine the delignification of Eucalyptus camaldulensis fibers by the kraft chemical process using sodium hydroxide and sodium sulfide as fillers. To optimize the levels of factors influencing pulp yield and pulp content, a response surface approach with a central composite plane was used. Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis were used to characterize the structure and thermal properties of cellulose fiber. Then, a dynamometer, a dechirometer, and an eclatometer adamel were used to evaluate the physico-mechanical properties (breaking length, tear resistance, and resistance to burst) of the paste. The results show that FTIR spectroscopy confirmed the structure of the cellulose fiber; the crystallinity index is 76.35%, the maximum degradation temperature is 368 °C and the kinetic energy of activation (75.45 kJ.mol-1) according to thermogravimetric studies. Subsequently, for the predicted optimal pulping conditions, the concentration of NaOH was 18.8% and 13.40% Na2S at 105 °C for 45 min. Finally, the results obtained for the evaluation of the papermaking properties of fibers during refining showed that the breaking length is 34% (2975 m–1958 m) with a sulfide concentration of 0%–30%, respectively, and that when the refining intensity is increased to 45°SR, the rupture length (5997-4088 m) decreases by approximately 31% under the same conditions. Then, the tear strength is 37.5% (53-33.1), the sulfide concentration is 0%–30%, and the refining intensity is 20°SR; the increase in the latter leads to a reduction in the tear index of approximately 19% (50-40.6) under the same conditions. Finally, the bursting index is 38.5% (18.4-11.3) at identical sulphide concentration and refining intensity, but the increase in the latter leads to a slight decrease in the burst index (37.7-23.6) which is about 37.40%. The results suggest that the valorization of Eucalyptus fibers for the production of well-delignified, high-yield, and resistant pulp is a promising approach. This research qualifies eucalyptus fiber as a potential reinforcement in composite materials.

Hydrothermal Synthesis of Silver Sulfide

Silver sulfide powders with submicro- and micrometer particle sizes have been synthesized by the hydrothermal method at temperatures from 373 to 453 K in aqueous and alcoholic solutions of silver nitrate, sodium sulfide and citrate, sulfur, and thiocarbamide. The crystal structures of the synthesized powders, morphology, composition, and particle size of silver sulfide have been analyzed by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, and gas adsorption. The powder particles have a similar morphology in the form of rectangular parallelepipeds and cubes with smoothed edges; the size of the powder particles depends on the synthesis conditions and ranges from ~500 to 2000 nm.

Crystalline properties and optical processes in copper sulphide nanoparticles synthesized by chemical precipitation method

In this study, we synthesized Copper sulphide (CuS) via chemical precipitation technique. The CuS nanoparticles were prepared using Cupric chloride and Sodium sulphide as precursors under specific conditions of rate of mixing the precursor solutions so that the growth rate was less than the nucleation rate. The powder form of particles was obtained through centrifugation, followed by annealing and grinding. For determining the morphological and compositional properties of prepared material, we recorded XRD data in the Θ − 2Θ geometry for the scan range of 20° to 80°. Analysing the XRD pattern of the prepared powder, we could identify the Covellite hexagonal phase for CuS. Further, the crystallite size in the 5–10 nm range was estimated using Scherrer relation. Moreover, the lattice parameters, crystal volume and strain were also calculated through Williamson-Hall (W-H) analysis. To examine the optical processes, the prepared particles were subjected to Ultraviolet–Visible (UV–Visible) spectroscopy. The UV–Visible spectra were measured in the absorbance range of 330–900 nm for water-suspended and alcohol-suspended CuS particle. The absorption spectra exhibit an absorption peak around 263 nm that is attributed to the blue shift owing to size quantization in nanosize CuS.

Synthesis of Mn2+ modified CdS nanoparticles and its application as catalyst in photodegradation of methyl red dye

Photocatalytic degradation of methyl red dye using Mn(5%) doped CdS nanoparticles was studied.Mn doped CdS nanoparticles was synthesized by microwave assisted solvo thermal method where the chemicals used wereCadmium Acetate [(CH3COO)2Cd, H2O], Manganese Chloride [MnCl2.2H2O] and Sodium Sulfide [Na2S.xH2O]. X-Ray diffraction(XRD) analysis was carried out in order to analyze the structural dimensions of the synthesized nanoparticles and the average crystallite size has been calculated at the full width half maximum (FWHM) of the diffraction peaks using Debye-Scherer equation and it was found to be around2.3nm. FTIR spectra analysis was done in order to analyze different functional and vibrational groups present in the as synthesized sample of Mn doped CdSnanoparticles.The morphology of sample wasstudied by scanning electron microscope. The aqueous solution of methyl red[C15H15N3O2] has been prepared and was mixed with the as synthesized Mn doped CdSnanoparticles and was exposed for photocatalytic degradation using 100 W bulb. UV-visible spectra of the light irradiated methyl red solutions were studied at different interval of time and no red shift was observed with increase of exposure time. The intensity of the absorption peak was also found to be reduced with the increasing time interval. The photo degradation of methyl red dye was observed up to 90% at the exposure time of 90 minutes.

Structural, optical and giant dielectric constant properties of pure ktenasite and schulenbergite/CuO minerals

In this study, schulenbergite [(Cu,Zn)7(SO4)2(OH)10·3H2O)]/CuO and pure ktenasite [(Cu,Zn)5(SO4)2(OH)6·6H2O)] minerals were simply synthesized via addition of sodium sulfide (Na2S) to a mixture of nanosized CuO powder dispersed into Zn(NO3)2·6H2O solution. The X-ray diffraction patterns illustrate the formation of schulenbergite/CuO mineral with ratio of 69:31% and 87/13% owing to additions of 0.1 and 0.2 mol L−1 Na2S, respectively. The addition of 0.4 mol L−1 Na2S substance lead to formation of pure ktenasite [(Cu,Zn)5(SO4)2(OH)6·6H2O)] mineral. The absorption vibration modes based on Fourier-transform infrared (FTIR) analysis verified the formation of schulenbergite/CuO and pure ktenasite compositions. The scanning electron microscope micrographs of schulenbergite/CuO and pure ktenasite samples reveal the formation of mixed grains with needle, sheets, cotton and wool shapes. The selected area electron diffraction images of the synthesized powders show strong dot-rings, indicating polycrystalline nature. Optically, all samples possess a high absorption ability for infrared-visible light wavelengths. At lower frequencies, the pellet of pure ktenasite sample exhibits giant dielectric constant characteristics. Exactly, pure ktenasite sample reveals a dielectric constant value of ~ 1.3 × 106 at frequency of 42 Hz. For schulenbergite/CuO (87/13%) sample, a large dielectric constant value of ~ 5311 was measured at frequency of 42 Hz. The colossal and variable relative permittivity values make the pure ktenasite [(Cu,Zn)5(SO4)2(OH)6·6H2O)] mineral is a suggested material for energy storage applications.

Obtaining of Luminescent Sulfur Nanoparticles in the L-Cysteine–Citrate–Sodium Sulfide System

Obtaining of Luminescent Sulfur Nanoparticles in the L-Cysteine–Citrate–Sodium Sulfide System

Effects of Sodium Sulphide as an Inhibitor on CdS Films Obtained by Chemical Bath Deposition

Effects of Sodium Sulphide as an Inhibitor on CdS Films Obtained by Chemical Bath Deposition

Effective sulfide flotation of cerussite by using trithiocyanuric acid as a novel sulfurizing reagent

The sulfide flotation of cerussite by adding traditional sulfurizing reagents, such as sodium sulfide, easily loses its effectiveness when inadequate or excessive reagents are added. In this study, cerussite flotation using trithiocyanuric acid (TTCA) as a novel sulfurizing reagent was investigated. Microflotation results indicated that cerussite could be effectively collected at pH 8.0 using trace amounts of TTCA as the sulfurizing reagent. The overdose TTCA had little effect on the effective flotation of cerussite. The sulfidization mechanism of cerussite by TTCA was investigated by zeta potential measurements, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results show that TTCA was mainly adsorbed on the cerussite surface in the form of a tautomer. TTCA-Pb complexes were produced by the chemical reactions of (H2C3N3S3)- monoanions with Pb atoms, which is beneficial for the adsorption of sodium butyl xanthate on the surface. The slow-release property of TTCA was confirmed by adsorption measurements. This property prevents the addition of excess sulfurizing reagents and maintains a continuous sulfurization atmosphere to significantly improve the flotation of cerussite.