Sodium Sulfide Research Articles

Halogenated polyethersulfone sulfides

This paper presents the results of a study of random copolyethersulfone sulfides based on 4,4-dichlorodiphenylsulfone, 1,1-dichloro-2,2-di(4-hydroxyphenyl)ethylene, and sodium sulfide. The synthesis of copolyethersulfone sulfides with different ratios of polyethersulfone and polyphenylenesulfone sulfide units was carried out by high-temperature polycondensation by the reaction of nucleophilic substitution in N,N-dimethylacetamide medium and using potassium carbonate as an alkaline agent. The effect of the solvent used on the yield and reduced viscosity of polyethersulfone sulfides was studied. It has been shown that polymers with high reduced viscosity can be obtained in N,N-dimethylacetamide and N,N-dimethylformamide. The growth dynamics of the reduced viscosity of polyethersulfone sulfides was also studied depending on the ratio of sulfone and sulfide groups. The solubility of these polymers in various solvents has been studied.

OPTIMIZATION OF RAWHIDE COLLAGEN DEFIBRILLIZATION PROCESS

The paper features the rawhide collagen defibrillization process in the elastic leather materials manufacturing. Optimal colloid-chemical properties of semi-processed products were defined by way of using mathematical optimization of rowhide liming process. It was found that during the alkaline treatment of raw material (in the operating temperature range) the degree of defibrillation of raw material raises (in proportion to the derm collagen swelling) with increase in the ratio of process solution to the mass of raw material, and the extremum of hydrothermal stability and leather yield can be estimated. It was also shown that the degree of swelling decreases with a decreasing ratio of sodium sulphide and sodium hydrosulphide, and the leather area yield reaches the maximum value at the equal proportion of these reagents. Multicriteria optimization of rawhide liming process using the Harrington’s desirability function was carried out. The developed technology of soaking and liming was tested under production conditions. The above-mentioned low-waste technology provides elastic leather materials with a yield increase by 3.5%, which meet the industry standards requirements.

STUDYING THE PROCESS OF SULFIDING AN OXIDIZED COPPER ORE BY THE METHOD OF MECHANOCHEMICAL ACTIVATION

In recent years, a new direction has appeared in metallurgical processes according to which the processing of concentrates is carried out by a combination of mechanical and metal-thermal methods of recovery. This contributes to the intensification of further redox processes and the production of fundamentally new modified products. In the case of enrichment of oxidized copper minerals, a more acceptable type of surface activation are mechanical activation processes with a combination of added reagents. It is established that sulfiding of oxidized copper minerals with elemental sulfur, silicon and sodium sulfides proceeds actively. As a result of the research, the optimal modes of sulfiding oxidized copper ores are determined. As a result of comprehensive research, a technology has been developed for processing oxidized copper minerals in a mill by sulfiding and subsequent flotation.

Room temperature, simple and efficient synthesis and functionalization of aromatic poly(arylene sulfide)s, poly(arylene sulfoxide)s and poly(arylene sulfone)s

Aromatic polysulfides and polysulfones are a large group of sulfur-containing polymers representing an important class of materials with diverse applications, ranging from high performance engineering plastics, gas separation, ultrafiltration, nanofiltration, ion-exchange membranes, and materials for biomedical applications. All these polymers are produced by high temperature nucleophilic substitution reactions of dichlorobenzene with sodium sulfide (PPS) and dichlorodiphenyl sulfone with bis-phenols in the presence of basic catalysts (PAES). In the present work, novel poly(arylene sulfide)s were obtained in nearly quantitative yields, by one-pot, room temperature, metal-free, highly regioselective, non-stoichiometric step-polymerizations of diphenyl sulfide (DPS) with 1,1,1-trifluoroacetone and isatin, in a mixture of trifluoromethanesulfonic acid (TFSA) with CH2Cl2. The polymers obtained were soluble in common solvents. The oxidation of the poly(arylene sulfide)s with H2O2 at room temperature afforded poly(arylene sulfoxide)s and poly(arylene sulfones) with high oxidation selectivity. On heating, sulfoxide groups of the poly(arylene sulfoxide)s are converted into sulfide groups and oxygen, which acts as an expanding agent, is released in the process to form nanofoams with homogeneous pore distribution. Controlled incorporation of hydroxymethyl-, carboxy-, and “click” able allyl- and propargyl- functionalities is carried out by room temperature, post-modification reactions of the polymers bearing reactive oxindole groups.

Green Synthesis for Battery Materials: A Case Study of Making Lithium Sulfide via Metathetic Precipitation.

For some future clean-energy technologies (such as advanced batteries), the concept of green chemistry has not been exercised enough for their material synthesis. Herein, we report a waste-free method of synthesizing lithium sulfide (Li2S), a critical material for both lithium-sulfur batteries and sulfide-electrolyte-based all-solid-state lithium batteries. The key novelty lies in directly precipitating crystalline Li2S out of an organic solution after the metathetic reaction between a lithium salt and sodium sulfide. Compared with conventional methods, this method is advantageous in operating at ambient temperatures, releasing no hazardous wastes, and being economically more competitive. To collect the valuable byproduct out of the liquid phases, a "solventing-out crystallization" technique is employed by adding an antisolvent (AS) of low boiling point. The subsequent distillation of the new solution under vacuum evaporates off the AS rather than the high-boiling-point reaction solvent (RS), saving a lot of energy. Consequently, the separated AS and RS containing the unreacted lithium salt can be directly reused. For industrial production, the entire process may be operated continuously in a closed loop without discharging any wastes. Moreover, Li2S cathodes and sulfide-electrolyte Li6PS5Cl derived from the synthesized Li2S show impressive battery performance, displaying the great potential of this method for practical applications.

Temperature Dependent Synthesis of Zinc Sulphide (ZnS) Nanoparticles and Its Characterization

Zinc sulphide nanoparticles (ZnS NPs) were successfully synthesized by chemical co-precipitation method at 20°C and 40°C using zinc chloride (ZnCl2 ) and sodium sulphide (Na2S) as precursors. Ascorbic acid was used as a capping agent. The synthesized ZnS NPs were characterized by X-ray diffraction (XRD), UV-visible and Fourier transform infrared (FTIR) spectroscopy. UV-visible spectra showed that the bandgap of synthesized NPs was 3.8-3.9 eV at two different temperatures. XRD analysis showed the particles were present in the cubic phase with a zinc blend structure. FTIR spectra were used in the confirmation of the chemical species of the synthesized NPs. The average particle size calculated by using Debye-Scherrer’s equation at 20°C and 40°C was found to be 5.01 and 3.1 nm which indicates that the particle size was temperature-dependent.

Optimizing the Infrared Photoelectric Detection Performance of Pbs Quantum Dots through Solid-State Ligand Exchange.

Lead sulfide (PbS) quantum dots (QDs) have attracted a great deal of attention in recent decades, due to their value for applications in optoelectronic devices. However, optimizing the performance of optoelectronic devices through ligand engineering has become a major challenge, as the surfactants that surround quantum dots impede the transport of electrons. In this paper, we prepared PbS QD films and photoconductive devices with four different ligands: 1,2-ethylenedithiol (EDT), tetrabutylammonium iodide (TBAI), hexadecyl trimethyl ammonium bromide (CTAB), and sodium sulfide (Na2S). A series of characterization studies confirmed that using the appropriate ligands in the solid-state ligand exchange step for thin film fabrication can significantly improve the responsivity. The devices treated with sodium sulfide showed the best sensitivity and a wider detection from 400 nm to 2300 nm, compared to the other ligand-treated devices. The responsivity of the champion device reached 95.6 mA/W under laser illumination at 980 nm, with an intensity of 50 mW/cm2.

Synergistic effect of Pd-Co3O4 nanoparticles supported on coffee-derived sulfur, nitrogen-codoped hierarchical porous carbon for efficient methanolysis of NaBH4

Sulfur, nitrogen-codoped (SN-doped) highly porous carbon nanostructures (CNSs) are established as efficient components for hydrogen generation applications. Waste coffee grounds are carbonized in situ and activated with KOH to produce hierarchically SN doped porous carbon nanostructures with a large specific surface area of 2320 m2 g−1. The amorphous and highly active Pd-Co3O4 nanoparticles (NPs) are anchored onto an SN-codoped carbon nanosheet prepared via a simple hydrothermal reaction. An effective method for optimization of the Pd-Co3O4/SN-CNS-600 catalytic efficiency for NaBH4 methanolysis using sodium sulfide as a precursor or combination of sulfur-containing salts as a raw material is proposed. The Pd-Co3O4/SN-CNS-600 catalyst exhibits an excellent catalytic activity for NaBH4 catalytic methanolysis at room temperature, with a high hydrogen generation rate of 20158 mL H2 min−1 gcat−1. The methanolysis reaction activation energy in an aqueous NaBH4 solution is approximately 14.52 kJ/mol. The excellent Pd-Co3O4/SN-CNS-600 catalytic activity is attributed to the small size and amorphous state of Pd-Co3O4 NPs, good synergistic interaction between Pd-Co3O4 NPs and SN-CNS with a large specific surface area, and abundant defects. Highly efficient, inexpensive, and environment-friendly catalysts are successfully developed for hydrogen generation.

Green synthesis of non-stoichiometric indium sulfide (In2.77S4) nanoparticles for water splitting and supercapacitance

The synthesis of electroactive multifunctional materials with high performance is an inherently challenging process. Furthermore, finding a green approach to make the process more feasible and convenient is highly desirable. Based on these challenges, herein, a facile and green microwave-assisted approach for the synthesis of phase pure sulfur-deficient indium sulfide (In2.77S4) nanoparticles is demonstrated. Green, economical and readily available reagents, such as castor oil and olive oil, were employed as green dispersants, solvents, and capping agents. Moreover, different sulfur-containing reagents, i.e., sodium sulfide, thioacetamide and thiourea, were employed in the synthesis to elucidate the effect of sulfur source on synthesized nanoparticles. Since electrocatalytic properties are significantly affected by the nature of the ligand on the surface of catalysts, therefore their performance for supercapacitance and water splitting is investigated. High-quality In2.77S4 prepared in castor oil, using thiourea as a sulfur source, showed satisfactory properties for energy storage such as specific capacitance of 540 F/g at 1 A/g current density as well as for both HER and OER with overpotentials of 158 and 346 mV, respectively.

Biogenic Production of Thiosulfate from Organic and Inorganic Sulfur Substrates for Application to Gold Leaching

Gold mining and processing is an activity with large environmental impact due to the low concentration of gold in ore deposits and chemical resistance to most chemicals. Over 75% of gold is leached from ores using cyanide, however less toxic lixiviants have been proposed in the literature. Thiosulfate is one of these alternative reagents, but high reagent consumption has slowed acceptance in mining operations. Reducing the cost and impact of thiosulfate production is a way to reduce the cost of reagent consumption during leaching. The objective of this study was to evaluate the feasibility of leaching gold from ore with biogenic thiosulfate. Biogenic thiosulfate was produced using a marine methylotroph bacterium from three substrates: sodium sulfide, elemental sulfur, and dimethyl sulfide for application in bioleaching. The different substrates were evaluated to determine conversion efficiency from the sulfur source to biogenic thiosulfate and verified by titration and ion chromatography. Optimal conditions for conversion to thiosulfate were determined to be in the range of pH = 7–8, 25–30 °C, with sodium sulfide as a substrate in a sealed system to prevent sulfide from escaping as hydrogen sulfide gas. An oxide gold ore with a grade of 4.02 g/t was selected as a gold source for leaching experiments. The leaching of gold using the biogenic thiosulfate was compared with chemical thiosulfate solutions under experimental conditions of pH = 9.5, 50 mg/L copper, 500 RPM mixing, and 0.1 L/min air. The efficiency of gold bioleaching was measured using flame atomic absorption spectroscopy and fire assay. Gold extraction efficiencies ranging from 20–60% were achieved using the biogenic thiosulfate, and 27–77% with sodium thiosulfate solutions, respectively. It was concluded that the sodium sulfide substrate was best for producing higher biogenic thiosulfate concentrations and leaching efficiency.

Assembly of Benzo[c][1,2]dithiol-3-ones via Acid-Promoted Denitrogenative Transannulation of Benzotriazinones.

An expedient synthesis of benzo[c][1,2]dithiol-3-ones via metal-free denitrogenative transannulation of benzotriazinones is developed, which represents the first example of acid-mediated heteroannulation of benzotriazinones. This newly discovered reactivity of benzotriazinones enables the streamline synthesis of diverse benzo[c][1,2]dithiol-3-ones in decent yields by using sodium sulfide as the sulfur source under simple reaction conditions.

Continuous Flow Synthesis of Cd1-x Znx S and CdS/ZnS Core/Shell Semiconductor Nanoparticles by MicroJet Reactor Technology.

From aqueous precursor solutions of metal salts and sodium sulfide using MicroJet Reactor (MJR) technology Cd1-x Znx S and CdS/ZnS core/shell semiconductor nanoparticles were synthesized. The MJR approach represents an automated, continuous, flexible and scalable route for nanoparticle synthesis, providing a tight control over process parameters and thus simple size, shape and composition control. Since particle sizes below the excitonic Bohr radius were obtained by MJR, the nanoparticulate materials exhibit quantum confinement effects. By varying the precursor ratio the band gap of Cd1-x Znx S Quantum Dots (QDs) could be targeted from 3.1 to 3.6 eV. CdS/ZnS core/shell QDs were prepared by enclosing CdS particles from MJR with ZnS produced by thermal decomposition of a Zn-MPA complex. Adjustment of the shell thickness increased the photoluminescence intensity by 43 %. Synthesis of ternary sulfides in the form of core/shell particles broadens the spectrum of materials accessible by MJR and demonstrates the extraordinary flexibility of the technology.

Development of a life cycle based process for cobalt recovering from cell batteries

Considering the great challenge of managing waste from electrical and electronic equipment (WEEE) , it is essential the creation of new recycling processes to allow efficiently the extraction of resources from this waste. Brazilians discarded about 114 million cell phones per year, and it represents an annual average amount of 456 tonnes of discarded cobalt that are in the Lithium-ion batteries (LIBs) of these cell phones. This value is higher than Brazil's production of cobalt in 2016 (400 tonnes), which was the last year that the country produced refined cobalt. The environmental impact from the implementation of mining processes is one of the biggest challenges to make these processes viable. However, recycling processes also have environmental impacts, whether through consumptions of energy, water, and other inputs. In this research the environmental impacts of five different developed and tested processes (scenarios) were developed and tested in one of the laboratories of the Federal University of Rio de Janeiro (COPPE/SAGE - Laboratory of Sustainable Production) to recover cobalt from cell phones Lithium-ion batteries (LIBs). The obtained results on the environmental impacts were compared with a reference scenario, related to obtaining of virgin cobalt from nature. This comparison was made using a methodology based on LCA (ISO 14040) to contrast environmental impacts. Overall, all five cobalt recycling routes developed in the laboratory had better environmental performance than the baseline scenario, however, the scenario considering the use of sodium sulphide as precipitating agent presented the best performance in most of the analysed environmental impact categories, obtaining reduction percentages of 43%, 90%, 96%, 98% and 72% for the Climate Change (GWP 100), Terrestrial Acidification (TA), Metal Depletion (MD), Water Depletion (WD) impact categories) and Fossil Depletion (FD) respectively. • Brazilians discarded about 114 million cell phones batteries per year; • In Brazil around 456 tonnes of cobalt from cell phones batteries are yearly discarded; • Five routes (scenarios) for recycling cobalt from Lithium-ion batteries (LIBs) were developed in the laboratory; • Environmental assessments of the developed routes were carried out using LCA; • The presented routes have lower environmental impacts than the reference scenario to the primary production of cobalt from mining.

Theoretical exploration of the structural evolution of sodium sulfide clusters in Na-S batteries

The nanosized sodium sulfide species greatly enhance the performance of Na-S batteries. However, as a typical ionic compound, the diminished stability with decreasing cluster size has been rarely considered. Numerous theoretical works only simulated the Na-S binary system based on quite small sodium sulfide clusters, with no account of the stability of the sub-nanoscale cluster. Here, by using an advanced structure search algorithm, we built a binary phase diagram of the sodium sulfide clusters (NSCs). The commonly studied monomer model with low sulfur concentrations is indeed energetically unfavorable, especially for the final discharge product, the Na2S monomer. Therefore, the aggregation of monomers should take place to form multimers. According to the energy, charge, and geometry, relatively stable clusters with low sulfur concentrations are located, including (Na2S5)2, (Na2S4)2, (Na2S3)3, (Na2S2)4, and (Na2S)6 clusters. Furthermore, these multimers bind more intensely to four typical models of carbon-based substrates. The B-doped carbon material exhibits outstanding affinity to NSCs, which may facilitate overcoming the shuttle effect in applications. This work represents a significant step toward understanding the evolution mechanism of NSCs that may guide the future development of high-performance Na-S batteries.

Ecological treatment of El Kriymat boiler ash for recovering vanadium, nickel and zinc from sulfate leach liquor

The primary goal of this work is to develop a technology that allows for the recovery of metal values from waste products, thereby promoting the wise and efficient use of our nation's resources. To achieve this goal, an industrial waste of El Kriymat boiler fly Ash was used for recovering its content of vanadium, nickel and zinc. About 97, 95 and 99% respectively of these economic elements were first dissolved from boiler fly ash magnetic concentrate (after physical concentration). Leaching experiments using optimum conditions include: 180 g/L sulfuric acid concentration and 4% solid/solid proportion manganese dioxide acts as an oxidant at 80 °C. The recovery of vanadium (V) metal ions was carried out using 3% Alamine 336 in kerosene at an equilibrium pH value of 0.9. Subsequently, 15% sodium sulfide solution was used for co-precipitation of nickel and zinc metal ions in the raffinate solution at pH value of 3.5.Graphical

Enhanced adsorption of sulfide and xanthate on smithsonite surfaces by lead activation and implications for flotation intensification

In the flotation of zinc oxide minerals, unavoidable lead ions (Pb2+) in the pulp interact with the mineral surface, sulfidizing reagents, and collectors. This interaction affects the sulfidization characteristics and xanthate adsorption on the surfaces of zinc oxide minerals. In this study, the mechanism of the interaction between Pb2+ and smithsonite surfaces, its effect on the surface sulfidization of smithsonite, and its response to xanthate adsorption were investigated. The flotation results showed that the addition of 5 × 10−4 mol/L Pb2+ in the pulp greatly increased the smithsonite flotation recovery. Pb2+ can interact with smithsonite surfaces to form a significant layer of lead-containing species. The amount of sulfide species on the smithsonite surface significantly increased after Pb2+ pretreatment and sulfidization. This shows that Pb2+ pretreatment promoted the reaction between the mineral surface and sodium sulfide because of the newly generated lead-containing species on the smithsonite surface. Infrared spectroscopy showed that the amount of xanthate adsorbed on the smithsonite surface in the Pb2+–sulfidization–xanthate system was larger than that in the sulfidization–xanthate system. An appropriate concentration of Pb2+ in the pulp before sulfidization could therefore promote sulfidization of smithsonite surfaces and improve xanthate adsorption. This would enhance the hydrophobicity of the smithsonite surfaces and increase the smithsonite flotation recovery.

Starch-Assisted Synthesis of Bi2S3 Nanoparticles for Enhanced Dielectric and Antibacterial Applications.

Starch [(C6H10O5) n ]-stabilized bismuth sulfide (Bi2S3) nanoparticles (NPs) were synthesized in a single-pot reaction using bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) and sodium sulfide (Na2S) as precursors. Bi2S3 NPs were stable over time and a wide band gap of 2.86 eV was observed. The capping of starch on the Bi2S3 NPs prevents them from agglomeration and provides regular uniform shapes. The synthesized Bi2S3 NPs were quasispherical, and the measured average particle size was ∼11 nm. The NPs are crystalline with an orthorhombic structure as determined by powder X-ray diffraction and transmission electron microscopy. The existence and interaction of starch on the NP's surface were analyzed using circular dichroism. Impedance spectroscopy was used to measure the electronic behavior of Bi2S3 NPs at various temperatures and frequencies. The dielectric measurements on the NPs show high dielectric polarizations. Furthermore, it was observed that the synthesized Bi2S3 NPs inhibited bacterial strains (Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) and demonstrated substantial antibacterial activity.

Mechanochemical Synthesis and Study of the Local Structure of NaGaS2 Glass and Glass-Ceramics.

NaGaS2 is a newly discovered compound that has already shown great promise for a variety of applications because of its layered structure and ion exchange properties. In this work, crystalline NaGaS2 has been synthesized by an alternative method to what has been previously published, namely, by mechanochemistry, either by a direct one-step process or by a two-step process. In the one-step process, crystalline NaGaS2 is directly formed by milling sodium sulfide Na2S and gallium(III) sulfide Ga2S3. However, an amorphous material is present in majority together with the crystalline phase. In the two-step process, amorphous NaGaS2 is first obtained by mechanical milling and then heated above its glass transition temperature to obtain a glass-ceramic mainly composed of crystalline NaGaS2. For the two-step process, changes of the local atomic-level structure in amorphous NaGaS2 and after crystallization were analyzed by high-field solid-state nuclear magnetic resonance (NMR) spectroscopy as well as by X-ray total scattering and pair distribution function (PDF) analysis. Based on quantitative analysis on the 23Na NMR spectra, modifying the annealing treatment can promote the formation of the crystalline phase up to a molar fraction of 83.8%.

ANALISIS TIMBAL (Pb) DAN KADMIUM (Cd) PADA KERANG BULUYANG DIPEROLEH DARI PASAR SEI SIKAMBING MEDAN SECARA KUALITATIF

Shellfish (Anadaraantiquata) is one type of shellfish that has the potential to be used as a food source in fulfilling the nutrition of the Indonesian people. Feather clams (Anadaraantiquata) belong to the class Bivalvia which are edible and have economic value. The purpose of this study was to determine the content of lead and cadmium in feather shells. Samples were taken from two fur shell traders at the Sei Sikambing market in Medan using a random sampling method with qualitative testing using disodium sulfide, potassium iodide, potassium chromate, potassium cyanide, and sodium hydroxide reagents, in accordance with work procedures. used in the Medan Regional Health Laboratory. The results showed that of the two samples tested, both samples did not contain lead (Pb) and cadmium (Cd).
 Keywords: Feather shells, lead (Pb), Cadmium (Cd), Qualitative.

Novel photoanodes based on (Mo-Cr) co-doped titania nanotube for highly efficient photocathodic protection performance of stainless steel

Mo-doped, Cr-doped, and Mo-Cr co-doped titania nanotube arrays were synthesized through the single step anodization of titanium. Mo-Cr co-doped titania nanotubes prepared showed great improvement on photocatalytic activity in the protection of stainless steel (403SS) under visible light irradiation compared with Mo and Cr mono-doped titania. The open-circuit potential (OCP) of 403SS (in 3.5 wt% aqueous NaCl) coupled with the best co-doped sample (Cr50:Mo50-TNT) was reduced from −240 to −690 mV, while the electrode potential was maintained at −320 mV even upon turning the light off. This study also identified the effect of the addition of sulfur compounds as hole scavengers on the photoelectrochemical (PEC) properties and photoelectrochemical cathodic protection (PCP) by the best Mo-Cr co-doped titania nanotube. Sodium sulfate and sulfite, sodium thiosulfate, sodium sulfide, potassium metabisulfite and thiourea have been used as hole scavengers. The order of photocurrent is as follows: Na2S > K2S2O5 > CS(NH2)2 > Na2S2O3 > no hole scavengers > Na2SO4 > Na2SO3. Mo-Cr co-doped titania nanotube show much more favorable PCP impact on 403SS than the pure titania sample, according to the results of the changes in the potentials and current densities. Furthermore, the results finally proved that sodium sulfide is the most appropriate hole scavenger.