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Heterogeneous catalysis holds great promise for oxidizing or reducing a range of pollutants in water. A well-recognized, but understudied, barrier to implementing catalytic treatment centers around fouling or aging over time of the catalyst surfaces. To better understand how to study catalyst fouling or aging, we selected a representative bimetallic catalyst (Pd-In supported on Al(2)O(3)), which holds promise to reduce nitrate to innocuous nitrogen gas by-products upon hydrogen addition, and six model solutions (deionized water, tap water, sodium hypochlorite, sodium borohydride, acetic acid, and sodium sulfide). Our novel aging experimental apparatus permitted single-passage of each model solution, separately, though a small packed bed reactor containing replicate bimetallic catalyst “beds” that could be sacrificed weekly for off-line characterization to quantify impacts of fouling or aging. The composition of the model solutions led to the following gradual changes in surface composition, morphology, or catalytic reactivity: (i) formation of passivating species, (ii) decreased catalytic sites due to metal leaching under acid conditions or sulfide poisoning, (iii) dissolution and/or transformation of indium, (iv) formation of new catalytic sites by the introduction of an additional metallic element, and (v) oxidative etching. The model solution water chemistry (solutes, Eh, pH) captured a wide range of conditions likely to be encountered in potable or industrial water treatment. Aging-induced changes altered catalytic activity and provided insights into potential strategies to improve long-term catalyst operations for water treatment.

A sulfur-involved ligation for thioamide quasi-peptides was developed via amino acids and amino aldehydes coupling. The key to the transformation was the chelation of copper with imines for chiral activation and fixation. In this environment, linear polysulfur decreased the alkalinity of single sulfur anions to prevent racemization caused by the interaction between sulfur and sodium sulfide. Dipeptides, tripeptides, tetrapeptides, and the linkage between the drug and amino acids were successfully obtained.

A strategy for modifying the structure of solid-state electrolytes (SSEs) to reduce the cation diffusion activation energy is presented. Two heavily W-doped sodium thioantimonate SSEs, Na2.895 W0.3 Sb0.7 S4 and Na2.7 W0.3 Sb0.7 S4 are designed, both exhibiting exceptionally low activation energy and enhanced room temperature (RT) ionic conductivity; 0.09 eV, 24.2 mS/cm and 0.12 eV, 14.5 mS/cm. At -15 °C the Na2.895 W0.3 Sb0.7 S4 displays a total ionic conductivity of 5.5 mS/cm. The 30 % W content goes far beyond the 10-12 % reported in the prior studies, and results in novel pseudo-cubic or orthorhombic structures. Calculations reveal that these properties result from a combination of multiple diffusion mechanisms, including vacancy defects, strongly correlated modes and excessive Na-ions. An all-solid-state battery (ASSB) using Na2.895 W0.3 Sb0.7 S4 as the primary SSE and a sodium sulfide (Na2 S) cathode achieves a reversible capacity of 400 mAh g-1 .

Background Oxalic acid (OA) existing widely in animal, plants, and factory processes may affect human health and result in environmental pollution. It is highly desired to develop a rapid fluorescent sensing for accurate determination of OA content in food and wastewater. Methods We are the first to design an easy-to-prepare rhodamine-6G based zinc complex as a fluorescent probe for the selective detection of OA and explore the sensing mechanism between zinc complex and OA. The zinc complex presents the coordination with two Zn2+ and both of rapid color and linear fluorescent response toward OA in the range of 0-10 μM. Findings The detection limit of the probe for OA can reach to 1.20 μM, which is superior to those reported in the literature. Compared with other dicarboxylic acids, the binuclear zinc complex probe displays rapid detection and high selectivity for OA over a wide pH range due to the steric hindrance and ring strains. The recycling of the probe can be achieved by the treatment with sodium sulfide to form zinc sulfide and regenerate the intermediate.

Investigated the synthesis of polyphenylene sulfide in the environment of an aprotic polar solvent based on p-dichlorobenzene and p-dibromobenzene according to the nature comonomer rating. Infrared spectroscopy and thermogravimetric analysis of the obtained samples are presented.

An approach to the synthesis of 1,3,5-dithiazinanes and 1,3,5-thiadiazinanes was developed based on the cyclothiomethylation of aliphatic amines with 9-aqueous Na2S and CH2O. Linear aliphatic primary amines form predominantly 1,3,5-thiadiazinanes, while branched ones lead to the formation of 1,3,5-dithiazinanes.

Cobalt-based oxides and hydroxides have always been one of the optimal catalysts for Oxygen Evolution Reaction (OER) in alkaline environment in recent years. However, it remains a challenge for simple cobalt oxides such as CoO, Co3O4 and CoOOH to provide high catalytic activity both with ideal conductivity and stability. Herein, we prepared a new type of sulfur-incorporated cobalt oxide nanocages as high efficiency OER catalyst using Co-MOF as precursor. With the help of sodium sulfide, one step water-warm immersion-alcohol refluxing method can achieve the cavitation of precursors and uniform incorporation of sulfur atoms meanwhile. The hollow cubic structure constructed by fluffy nanosheets is beneficial to the exposure of active sites, the regulation of electronic structure and improve the electron transfer speed. After electrochemical testing, the prepared CoS@CoO showed outstanding OER activity compared with other cobalt-based catalysts. More importantly, this material has also withstood the electrochemical test of long range due to the stable structural foundation provided by Co-MOF. This work comes up with a new idea for OER activity promotion of hollow doped cobalt-based catalysts through morphology control and electronic structure optimization.

The presence of arsenic in base metal concentrates including copper, lead, and zinc creates problems such as low quality of final product and environmental issues. Therefore, additional processing steps for removing arsenic are required. Among several methods to reduce arsenic from these concentrates, alkaline leaching was selected as an efficient and simple method. In this research, sodium sulfide and sodium hydroxide mixtures were used for arsenic elimination from lead concentrate produced by Zarrin Madan Asia Company. To obtain optimum conditions, the effect of some parameters such as temperature, leaching time, liquid/solid ratio (L/S), sodium sulfide, and sodium hydroxide concentrations on arsenic removal was investigated. Based on characterization methods, mimetite was the main arsenic compound in lead concentrate; however, after alkaline sulfide leaching, the starting material was decomposed, and lead was mainly transformed to PbS. Accordingly, up to 98% of arsenic was removed under optimum selective leaching conditions (30 g/L of sulfide sodium, 5 g/L of sodium hydroxide, at 85 °C, 15 min, and L/S ratio = 7). To immobilize arsenic from alkaline leaching, the precipitation method was used by finding optimum conditions (at Fe/As = 3, 25 °C and 12 h). Therefore, the final product was suitable for further smelting processes without any environmental problems.

Thin films of zinc sulfide (ZnS) with different concentrations of zinc acetate have been made by chemical bath deposition technique in acidic medium (pH = 5) on glass substrate using zinc acetate and sodium sulfide as sources of Zn+2 ion and S−2 ion, respectively, and ethylenediaminetetraacetate as complexing agents and sulfuric acid to adjust pH value at a constant deposition temperature of 85°C, and the deposition time of 90 minutes was used. The effect of the concentration of metallic precursor on the structural, morphological, and optical properties of chemical bath deposited zinc sulfide thin films was investigated in this study. The XRD result confirmed mixed phases of crystalline and amorphous structure dominating other phases, which is witnessed by larger crystallite size than other phases. It reveals that the thin films had hexagonal structure at the medium concentration with preferred orientation along (111) plane, and at lower and higher concentration, it showed that film has an amorphous structure in nature. The crystallinity of all the phases significantly enlarged with increasing the zinc precursor concentration. The SEM micrographs showed high-pitched edged irregular-shaped grains covering the substrate with pinholes and bangs. The optical properties investigated by the UV-VIS spectrometer specified a decrease in the optical bandgap of the films between 3.5 eV and 2.6 eV as the zinc acetate concentration in the solution increased from 0.1 to 0.2 M. It showed that the zinc sulfide had high absorption in the UV radiation. The main finding of this paper is that metallic precursor concentration has a significant role in the optical, morphological, and microstructural properties of the cobalt sulfide thin films, which are most suitable for photovoltaic applications.

A technological scheme for the synthesis of an aluminosilicate sorbent in laboratory conditions using clay from the Semilukskoye deposit has been developed. When the sorbent sample is heated in the range of 30-225 ° C, a loss of free moisture occurs, in the temperature range of 405-550 ° C, bound water begins to evaporate and decomposition of organic substances occurs. The sorption of sodium sulfide by the sorbent surface has been studied. The constants ? and n are determined in the Freundlich equation A = 1.38 ? C1.19. Formed specific surface area S = 12.8 m2 / g. A comparative study of the acid-base properties of the surface of the synthesized aluminosilicate sorbent and diatomite Celite 545 60/80 MESH by the indicator method has been carried out. The adsorption on the acid-base centers of the synthesized aluminosilicate sorbent surface is higher than the adsorption on the diatomite surface. On the surface of the synthesized aluminosilicate sorbent, there are both acidic (pK = 1.7; 3.46) and basic (pK = 18.8; 9.2) Bronsted centers The pore volume of the synthesized aluminosilicate sorbent corresponds to 0.25 cm3 / g. This value is less than the pore volume of diatomite 1.86 cm3 / g.

Sodium sulfide has been widely used as a bismuth depressant in the flotation separation of molybdenum–bismuth sulfide ores. However, the selective depression mechanism of sodium sulfide on bismuthi...

Anionic, cationic and cationic/anionic flotation is widely used in the concentration process for low-grade oxidized zinc ores. In the cationic flotation route, sodium silicate is used as a depressa...

It is shown that the catalytic center of Thiocapsa roseopersicina remains active after prolonged treatment with cyanide. It was found that the incubation of cyanide-treated hydrogenase in the presence of beta-mercaptoethanol, ferric iron, and sodium sulfide restored the hydrogenase activity in the hydrogen-oxidation reaction in the presence of methylviologen. The process of activity reconstruction depended on time and reached its maximum value (~ 60%) within 30 min at room temperature. In this case, an absorption band at 420 nm appeared in the absorption spectrum of the hydrogenase, which was present in the native hydrogenase and disappeared after treatment with cyanide; this indicated the reconstruction of iron–sulfur clusters. Thus, instead of growing bacteria in the presence of an iron isotope, one can replace 56Fe with 57Fe in the isolated enzyme, which will allow the use of smaller amounts of 57Fe.

Novel anion-exchange resins were prepared from asphaltenes by nitration with nitric acid followed by reduction of the nitrated asphaltenes with sodium sulfide. The aminated asphaltenes were investigated as anion exchange resins for the treatment of phenol-containing wastewater. Their maximum adsorption capacity was found to be 2.3-fold superior to that of an industrial AV-17-8 (OH– form) AER sample.

Products of the interaction between dispersed copper(II), iron(III) (hematite), and titanium(IV) (rutile) oxides and aqueous solutions containing liquid prenucleation intermediates formed in the reaction of HAuCl4 and sodium sulfide with the initial 1:3 molar ratio of the reagents are studied by X-ray photoelectron spectroscopy, Cu L-, Fe L-, Ti L-, O K X-ray absorption near edge structure spectroscopy in combination with transmission electron microscopy. It is found that in comparison with treatment of supports with a HAuCl4 solution, the amount of deposited gold significantly increases in the presence of sulfide ions. Gold nanoparticles covered with adsorbed sulfur form on three studied oxides as a decomposition product of strongly disordered gold(I) sulfide. On copper oxide, discernibly larger gold nanoparticles (with a diameter of about 10 nm against 3-5 nm on hematite and rutile) are observed. The surface of the support is sulfidized.

In recent years, multicomponent reactions with inorganic and organic sulfur compounds as one of reactants have achieved a remarkable development. In this review, we summarize recent advances in the multicomponent reactions involving sulfur components, which include elemental sulfur, sodium metabisulfite, sodium hyposulfite, potassium pyrosulfite, DABSO, sodium sulfide, thiocyanate, sulfur dioxide, carbon disulfide and other divalent, tetravalent and hexavalent organosulfur compounds.

The MIS-structures of InSb with anodically grown dielectric coating in galvanostatic mode in sodium sulfide solution were studied. Fast and slow surface states extracted by using the C–V characteristics method. The extracted values of Dit and NF were 2 × 1011 cm–2 eV–1 and 9.2 × 1010 cm–2, respectively. The hysteresis behavior was investigated. Additional sulfidation pretreatment using (NH4)2S–ethylenglycol solution lower the value of hysteresis and 25% reduce the interface state density. The arithmetic average roughness after anodizing increases from 0.6 to 0.9 nm, but preliminary sulfidation does not significantly affect this parameter. The formed dielectric coating has sufficient film continuity for its use as a passivating coating of InSb based FPA’s.

We report the synthesis of Ag nanocubes by using a sodium sulfide assisted solvothermal method. Small edge-length nanocubes (32 and 44 nm) were obtained at 145 and 155 °C reaction temperature in the synthesis process. The refractive index sensitivity of synthesized nanocubes was investigated with an aqueous solution of glucose. The refractive index sensitivity of 161 nm per RIU was found in the colloidal dispersion of nanocubes. On the LSPR chip made by immobilization of nanocubes on the (3-aminopropyl)trimethoxysilane modified glass coverslip, the obtained sensitivity was 116 nm per RIU. Detection of formaldehyde in water and milk samples was also performed with nanocubes of edge-length of 44 nm. Formaldehyde detection was performed by utilizing the interaction of the aryl amine of 4-aminothiophenol immobilized on the nanocubes and electrophilic carbon atom of the formaldehyde. In water and in diluted milk, the formaldehyde sensitivity of 0.62 and 0.29 nm μM−1 was obtained, respectively.

Hydrogen generation via water electroreduction is pivotal for exploiting clean-energy skills. Nevertheless, developing a low price and high-performance catalytic activity substance to take the place of expensive precious metal currently in use is still a precedent condition for technology commercialization. In this study, large-scale hierarchical few-layer MoSe2 nanosheets were successfully grown on the surface of sodium sulfide crystals. The water solubility of sodium sulfide makes it advantageous to generate MoSe2 nanolayers via a simple and inexpensive means. The micron-level sodium sulfide crystal surface has a very critical function in the nucleus formation and development of few-layer MoSe2. The ultrathin hierarchical MoSe2 nanolayers obtained using the proposed approach have preferable hydrogen evolution reaction. Furthermore, it is a fascinating technique that the template can be reused without environmental pollution. This research can be used to manufacture other ultrathin hierarchical transition-metal dichalcogenide nanolayers for high-performance many-sided applications.

It is difficult to avoid the formation of polysulfides by traditional chemical methods, and the synthesis of high purity amorphous MoS2 nanomaterials under ambient conditions is still a challenging task. Here we present a new and facile photochemical strategy for the synthesis of amorphous MoS2 nanomaterials, which is achieved by irradiating a mixed solution containing ammonium molybdate, formic acid and sodium sulfide simply with a Xe lamp for 3 min. The mechanism study reveals that the key step in this synthesis is the photolysis of formic acid to produce free radicals which can rapidly reduce Mo6+ to Mo4+, which then combines with S2− to form MoS2 and inhibits the formation of S–S2− by preventing S2− from participating in the reduction reaction. In addition, the results of a series of experiments indicate that the as-prepared amorphous MoS2 features a small particle size, uniform morphology and relatively large specific surface area, and shows excellent performance in the removal of inorganic heavy metal ions (mercury, lead and cadmium ions) and organic pollutants (rhodamine B and tetracycline), catalase catalysis and a lithium battery anode, showing its great potential and broad application prospects in the fields of environmental remediation, clean energy and green catalysis.

A complexation strategy has been demonstrated for the fabrication of an organic–inorganic hybrid system, where the organic molecule aniline acted as a ligand for the complexation of antimony chloride. By the addition of a sulfide source (sodium sulfide) to the complex medium, an organic–inorganic composite system (aniline stabilized antimony sulfide) was developed. X-ray diffraction analysis confirmed the formation of orthorhombic antimony sulfide and the microscopic images showed the formation of highly dispersed sulfide nanoparticles on the organic matrix. The optical characterization exhibited changes of characteristic vibrational bands in the FTIR spectrum that support complexation and the particle formation process. The as-synthesized product, aniline stabilized antimony sulfide, was applied as an active material of a device to extract the electrical properties under normal laboratory illumination (LED) and UV irradiation conditions. The device exhibited unipolar and bipolar switching behaviours under two different optical conditions with a moderately high ON-to-OFF ratio. The transport mechanism of the aniline stabilized antimony sulfide-based device was followed by Poole–Frenkel, Ohmic and Schottky emission at different conduction states. The device showed a persistent endurance behaviour, and statistical analysis suggested a stable high conduction state (HCS) and low conduction state (LCS) under LED and UV irradiation conditions. Furthermore, the impedance measurement of the device over the frequency range from 100 Hz to 1 MHz under both LED and UV irradiation conditions was performed to find out the device equivalent circuit and AC conductivity behaviour.

A general and efficient strategy for the one-pot synthesis of isothiocoumarin-1-ones has been developed via the base-promoted 6-endo-dig thioannulation of o-alkynyl oxime ethers using the cheap and readily available Na2S as the sulfur source. Mechanistic studies disclosed that the reaction proceeded through two C-S bond formations, N-O bond cleavage and the final hydrolysis of imines.

Sulfur-oxidizing bacterias were isolated then grown on salak fruit seeds forming bio-film. Their performances in sulfide removal were experimentally observed. The salak fruit seeds were then used as packing material in a cylinder. Liquid containing 83 ppm of sodium sulfide was flown through the bed. Then the sulfide concentrations in the outlet at various times were analyzed. A set of simple kinetics model for the rate of the sulfide removal and the bacterial growth was proposed. The axial sulfide concentration gradient in the flowing liquid are assumed to be quasi-steady-state. Mean while the bio-film grows on the surface of the seeds and the sulfide oxidation takes place in the bio-film. Since the bio-film is very thin, the sulfide concentration in the bio-film is assumed to be uniform. The simultaneous ordinary differential equations obtained were then solved numerically using Runge-Kutta method. The accuracy of the model proposed was tested by comparing the calculation results using the model with the experimental data obtained. It turned out that the model proposed can be applied to quantitatively describe the removal of sulfide in liquid using bio-filter in packed bed. The values of the parameters were also obtained by curve-fitting.

It is known from the literature, that organic tellurium compounds have valuable biological properties. One example of such type of compounds is organic ditellurides. There are also known the usage of ditellurides as initiators in the synthesis of polymers, and they are widely used as synthons for the synthesis of another organotellurium compounds. In particular, the halogenation of diarylditellurides leads to the formation of such electrophilic reagents as aryltellurium trihalides, which proved to be suitable substrates for the synthesis of heterocyclic compounds. This paper describes a method for the synthesis of ditellurides, which contain condensed heterocycles of the quinazoline and thienopyrimidine series, by reducing of the corresponding heteryltellurium trichlorides. The interaction of 2-methyl-2-(trichlorotelluromethyl)-2,3-dihydro-5 H -thiazolo[2,3- b ]quinazolin-5-one hydrochloride with a 4-fold excess of 9-aqueous sodium sulfide in water at room temperature leads to formation of 2,2'-(ditellanidylbis(methylene))bis(2-methyl-2,3-dihydro-5 H -thiazolo[2,3- b ]quinazolin-5-one) with high yield. The introduction of the trifluoromethyl group at the 8 th position of 2-methyl-2-(trichlorotelluromethyl)-2,3-dihydro-5 H -thiazolo[2,3- b ]quinazolin-5-one hydrochloride increases the yield of the target ditelluride. 2-[(Trichlorotelluro)methyl]-2,3,6,7,8,9-hexahydro-5 H -benzo[4,5]thieno[2,3- d ]thiazolo[3,2- a ]pyrimidin-5-one hydrochloride was used for the study of the impact of the condensed with pyrimidine moiety cycle on the formation of ditellurides in the sodium sulfide reduction reaction and it was stated that under the found conditions it is uniformly converted into 2,2'-(ditellanidylbis(methylene))bis(2,3,6,7,8,9)-hexahydro-5 H -benzo[4,5]thieno[2,3- d ]thiazolo­[3,2- a ]-pyrimidin-5-one). The obtained ditellurides were used in the bromination reaction. It was found that the interaction of the starting ditellurides with a triple excess of bromine in chloroform medium allows obtaining the tribromides of the thiazoloquinazoline and thiazolothienopyrimidine series selectively. Therefore, the hydrochlorides of trichlorotelluromethyl-substituted thiazolinopyrimidines can be reduced to bis heterylditellurides, which under bromination conditions form tribromotelluromethyl-substituted thiazolinopyrimidines.

The leaching kinetics of antimony from refractory gold ore in alkaline sodium sulfide was investigated under ultrasound. The influence of factors such as stirring speed, temperature, the concentration of sodium hydroxide and sodium sulfide and particle size, was studied. The leaching kinetics has also been studied under convention and ultrasound. The experimental data are consistent with the shrinkage core model and the leaching rate is controlled by surface chemical reaction for both ultrasonic and the conventional method. Ultrasound increases the leaching rate of antimony from 81.2% to 93.1%. It can be seen that the rate constant kr of ultrasonic method at various temperatures is larger than that of the conventional method. The ultrasound reduces the apparent activation energy from 48.39 kJ/mol to 33.88 kJ/mol and reduces the apparent response series of sodium sulfide concentration from1.3 to 1.1. Comparing with conventional method, the ultrasound can greatly improve the antimony leaching rate, accelerate the leaching process and lower temperature and the concentration of sodium hydroxide and sodium sulfide. These advantages of ultrasonic method were also confirmed by the SEM analysis of the leached solid.

Passivation of the n-InP(100) surface with sodium sulfide (Na2S) aqueous solution is analyzed by photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS). The room-temperature PL intensity increases essentially even after short treatment with sulfide solution for 1 min. The enhancement in the room-temperature PL intensity after passivation decreases with the increase in the bulk doping level of the semiconductor. Time-resolved PL studies performed at liquid-nitrogen temperature indicate reduction in the surface recombination velocity. This improvement of the PL intensity occurs just after transformation of the native oxide layer consisting mainly of indium phosphates to the passivating layer consisting of indium sulfides and oxides. The surface bands in n-InP(100) remained nearly flat both before and after sulfide passivation.

Sodium-conducting sulfide glasses are promising materials for the next generation of solid-state batteries. Deep insight into the glass structure is required to ensure a functional design and tailoring of vitreous alloys for energy applications. Using pulsed neutron diffraction supported by first-principles molecular dynamics, we show a structural diversity of Na2S-As2S3 sodium thioarsenate glasses, consisting of long corner-sharing (CS) pyramidal chains CS-(AsSS2/2)k, small AspSq rings (p + q ≤ 11), mixed corner- and edge-sharing oligomers, edge-sharing (ES) dimers ES-As2S4, and isolated (ISO) pyramids ISO-AsS3, entirely or partially connected by sodium species. Polysulfide S-S bridges and structural units with homopolar As-As bonds complete the glass structure, which is basically different from structural motifs predicted by the equilibrium phase diagram. In contrast to superionic silver and sodium sulfide glasses, characterized by a significant population of isolated sulfur species Siso (0.20 < Siso/Stot < 0.28), that is, sulfur connected to only mobile cations M+ with a usual M/Siso stoichiometry of 2, poorly conducting Na2S-As2S3 alloys exhibit a modest Siso fraction of 6.2%.

Corrosion by sulfur compounds is a long-standing challenge in many engineering applications. Specifically, designing a coating that protects metals from both abiotic and biotic forms of sulfur corrosion remains an elusive goal. Here we report that atomically thin layers (∼4) of hexagonal boron nitride (hBN) act as a protective coating to inhibit corrosion of the underlying copper (Cu) surfaces (∼6-7-fold lower corrosion than bare Cu) in abiotic (sulfuric acid and sodium sulfide) and biotic (sulfate-reducing bacteria medium) environments. The corrosion resistance of hBN is attributed to its outstanding barrier properties to the corrosive species in diverse environments of sulfur compounds. Increasing the number of atomic layers did not necessarily improve the corrosion protection mechanisms. Instead, multilayers of hBN were found to upregulate the adhesion genes in Desulfovibrio alaskensis G20 cells, promote cell adhesion and biofilm growth, and lower the protection against biogenic sulfide attack when compared to the few layers of hBN. Our findings confirm hBN as the thinnest coating to resist diverse forms of sulfur corrosion.

Improving the collagen structure, which was impacted by the curing process, increases the efficiency of all subsequent structural transformations during leather production and results in the formation of a high-quality leather material. Herein, we studied the process of soaking green-salted horsehides in electrochemically activated aqueous solutions and the properties of resulting chrome-tanned leather. It was found that the process of soaking horsehides can be effectively carried out using an electrochemically activated solution (ECAS) – a mixture of catholyte and anolyte at a volume ratio of 5 : 1. Using this soaking solution, sodium sulfide (an environmentally harmful reagent), sodium carbonate, and detergent can be completely excluded from the technological solution. The use of ECAS at the soaking stage effectively regenerates the water balance of horsehides while maintaining a stable pH during the soaking process and increases the efficacy of liming and all subsequent processes. Considering the prominent structural differences (density and thickness) between the front and shell of horsehide, the developed method, which utilize ECAS for soaking, allows the entire process to be carried out on uncut horse hides instead of processing two parts separately, which is normally required. The chrome-tanned leather produced by the developed method in semi-industrial conditions has elastic-plastic properties which are superior compared to the leather produced by current technology. The developed method also results in increasing the area yield by 2.5%. The resulting elastic leather can be used for manufacturing a variety of articles, including clothing, accessories, and footwear.

It is for the first time that silver sulfide colloidal solutions were prepared by chemical deposition from silver nitrate and sodium sulfide solutions in heavy water D2O. Sodium citrate served as the stabilizer. The sizes of Ag2S nanoparticles in colloidal solutions were assessed by dynamic light scattering (DLS) measurements and electron microscopy. The silver sulfide nanoparticles in heavy water colloidal solutions prepared from batches having various reagent concentrations had sizes in the range from 3 to 19–20 nm. The increasing silver nitrate concentration and decreasing sodium citrate concentration in the batch only slightly increased the sizes of Ag2S nanoparticles in the prepared colloidal solutions. The silver sulfide colloidal solutions prepared with heavy water D2O retained their stability and unchanged nanoparticle sizes when stored for more than 100 days.

With significantly decreased light scattering and tissue autofluorescence, fluorescence imaging in the second near infrared (NIR-II, 1000-1700 nm) region has been heavily explored in biomedical field recently. Silver sulfide quantum dots (Ag2S QDs) with unique optical properties were one of the most classic NIR-II imaging probes. However, the Ag2S QDs for in vivo purpose were mainly obtain by oil phase-based high-temperature route at present. Here, we proposed a mild aqueous route to prepare NIR-II emissive Ag2S QDs for in vivo tumor imaging. Original Ag2S QDs was obtained by mixing sodium sulfide and silver nitrate in a thiol-terminated polyethylene glycol (mPEG-SH) solution. Treating the original Ag2S QDs with extra mPEG-SH ligands produced highly PEGyalted Ag2S QDs. These re-PEGylated Ag2S QDs exhibited much better blood circulation and tumor accumulation in vivo comparing with the original ones, which can serve as excellent tumor imaging probes. The whole-body blood vessel imaging of living mice was achieved with high resolution, the bio-distribution of these QDs were studied by NIR-II imaging as well. This work also highlighted the importance of ligand density for tumor targeting.

Zinc sulfide ZnS nanopowders were prepared by chemical deposition from aqueous solutions of zinc nitrate and sodium sulfide in the presence of sodium citrate or Trilon B. ZnS/Ag2S heteronanostructures were prepared by two-step chemical codeposition of zinc and silver sulfides. The prepared ZnS nanopowders had average particle sizes ranging from 2 to 10 nm depending on the reagent concentration ratio in the batch. The nanoparticle sizes in the thus-prepared heteronanostructures were 8–10 nm. The diffuse reflectance spectra of nanostructured ZnS and ZnS/Ag2S heteronanostructures were measured. The bandgap width Eg in the studied sulfide nanostructures was assessed based on an examination of the measured optical absorption spectra. As the nanoparticle size decreased from 10 to 2 nm, the Eg in ZnS nanopowders increased in the range 3.59–3.72 eV. The increasing Ag2S percentage in ZnS/Ag2S heteronanostructures leads to narrowing of the bandgap. Pulsed cathodoluminescence (PCL) spectra were recorded. The luminescence characteristics of ZnS and ZnS/Ag2S depend on the preparation method and nanoparticle morphology.

Treatment of substituted 1,3,5-trithianes with S2Cl2 and Na2S under mild conditions provides 3,5-disubstituted 1,2,4-trithiolanes, as mixture of diastereoisomers.

In this research, keratin was extracted from the waste wool fiber using sodium sulfite as dissolving agent. The reaction results showed that the optimum conditions were as follows: the dosage of so...

With the purpose of fully understanding the potential toxicity of heavy metals of various particle sizes in fly ash (FA) and finding an optimal chemical reagent stabilization scheme for fly ash with single or mixture reagents, basic physicochemical characteristics of FA was investigated using multiple chemical stabilization reagent schemes to stabilize heavy metals. The following compounds were used to develop single and mixed chemical stabilization schemes for heavy metals in waste incineration FA: sodium sulfide (Na2S), sodium dihydrogen phosphate (NaH2PO4), ammonium dibutyl dithiophosphate (DDTP), and 2,4,6-tri-mercapto-S-triazine trisodium salt (TMT-15). The results showed that the various particle sizes of FA were mainly distributed in the range of 48–1700 μm. FA was packed with heavy metals, and the smaller the particle size, the more toxic it was. The speciation distribution of Cu, Zn, Pb, Cd, and Cr in different particle sizes was identical to that of the mixed samples. In the experiments of single reagent stabilization scheme, 8% Na2S, 8% NaH2PO4, 4.2% DDTP or 4.2% TMT-15 could decrease the leaching concentration to meet the limits set by Chinese law, but 8% Na2S adding scheme had the lowest cost among them. However, in the mixture reagent scheme, 1.2% Na2S, 1.2% NaH2PO4 and 0.8% DDTP was more effective and even cheaper than other mixture or single schemes.

A novel domino reaction from benzaldehydes and 2-acetylfuran/2-acetylthiophene with sodium sulfide was developed to synthesize a series of tetrahydrothiopyran (THTP) derivatives. The reaction proceeded well to construct a tetrahydrothiopyran ring and five new bonds in one step. A mechanism is proposed, involving a stepwise Aldol/double Michael addition/Aldol (AMMA) reaction cascade. In this transformation, sodium sulfide acts as a nucleophile and base. This method is characterized by transition-metal-free, commercially available starting materials and mild reaction conditions.

Cadmium-tolerant (6 mM)Aspergillus niger(RCMB 002002) biomass was challenged with aqueous cadmium chloride (1 mM) followed by sodium sulfide (9 mM) at 37°C for 96 h under shaking conditions (200 rpm), resulting in the formation of highly stable polydispersed cadmium sulfide nanoparticles (CdSNPs). Scanning electron microscopy revealed the presence of spherical particles measuring approximately 5 nm. A light scattering detector (LSD) showed that 100% of the CSNPs measure from 2.7 to 7.5 nm. Structural analyses by both powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirmed the presence of cubic CdS nanoparticles (CdSNPs) capped with fungal proteins. These CdSNPs showed emission spectra with a broad fluorescence peak at 420 nm and UV absorption onset at 430 nm that shifted to 445 nm after three months of incubation. The CdSNPs showed antimicrobial activity againstE. coli,Pseudomonas vulgaris,Staphylococcus aureus, andBacillus subtilis, and no antimicrobial activity was detected againstCandida albicans. The biosynthesized CdSNPs have cytotoxic activity, with 50% inhibitory concentrations (IC50) of 190 μg mL-1against MCF7, 246 μg mL-1against PC3, and 149 μg mL-1against A549 cell lines.

Nanocrystalline powders of lead sulfide with particle size from 5 to 105 nm have been synthesized by chemical deposition from aqueous solutions of lead acetate or nitrate using sodium sulfide as sulfidizing agent and in the presence of sodium citrate or Trilon B as complexing agents. The exposure of the nanopowders to air for six years has shown that PbS nanopowders obtained in the presence of sodium citrate Na3Cit, which behaves as both complexing and stabilizing agent, display the largest stability of phase composition. The stabilizing role of Na3Cit is due to its ability to form a shell on nanoparticle surface to prevent lead sulfide oxidation. It has been established that nanoparticle size remains constant and stable upon long-term keeping in air. The phase composition of PbS nanopowders prepared using Trilon B gradually changes owing to oxidation into lead sulfate upon long-term exposure to air.

The use of coal fly ash as a new support for a reagent for organic synthesis was investigated. Coal fly ash supported sodium sulfide was found to be an effective reagent for the synthesis of dithiacyclophanes, notably giving better results than alumina-supported sodium sulfide.

The extraframework sodium sulfide cationic cluster, Na4S2+, has been introduced into zeolite Y (FAU, Si/Al = 1.56). A single crystal of |Na73(Na4S2+)1.0|[Si117Al75O384]-FAU was prepared by allowing aqueous 0.1 M Na2S solution to flow past a |Na75|[Si117Al75O384]-FAU crystal, and followed by vacuum dehydration at 723 K. Its structure was determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group Fd $$\overline{3}$$ m. The structure was refined using all intensities to the final error index R1/wR2 = 0.044/0.125. About 77 Na+ ions per unit cell are found at the crystallographically distinct positions, six. One Na+ ion per unit cell is at the center of double 6-ring. Two site-I′ positions are occupied by 26.5 and 4 Na+ ions, respectively, per unit cell. Thirty-two Na+ ions per unit cell are found at site II, in the supercage opposite single 6-rings. The remaining 4.5 and 9 Na+ ions per unit cell occupy two sites III′ near triple 4-rings in the supercage. Finally, one sulfide ion per unit cell, associated with Na+ ions, is found at the center of sodalite cavity. The 4 Na+ ions at site I′ coordinate to a sulfide ion at the center of sodalite cavity to give tetrahedral cationic cluster, Na4S2+. In |Na73(Na4S2+)1.0|[Si117Al75O384]-FAU, tetrahedral Na4S2+ ions center about 12.5% of the sodalite cavities.

This article covers a hydrometallurgical method for processing of a gold-antimony flotation concentrate in alkaline sulfide solutions. Thermodynamic analysis of the reaction stibnite with sulfide sodium and sodium hydroxide was performed. The chemical and phase compositions of the investigated material, mainly represented by compounds of antimony, silicon, calcium, sulfur and iron are studied. Phase composition: quartz, stibnite, quicklime, pyrite, dolomite and arsenopyrite. The dependences of the influence of sulfide sodium and sodium hydroxide concentration, and the liquid to solid ratio on antimony extraction into solution were determined by methods of mathematical experiment planning. The calculated values ​​of the determination coefficients testify to the adequacy of the chosen two-level model. The optimum parameters of the process were obtained: L/S ratio = 4,5; the nitric acid sulfide sodium concentration was 61.09 g/L; sodium hydroxide concentration was 16.47 g/

To remove the adsorbed reagent of copper–lead mixed concentrate in bulk flotation, this study investigates the removal effect of sodium sulfide (SS) through micro-flotation, adsorption tests, equilibrium speciation analysis, electrochemical analysis, and first-principle density functional theory (DFT) calculations. Micro-flotation tests demonstrate that chalcopyrite and galena recovery remarkably decline by 50% and 70%, respectively, because of SS addition in a mineral–butyl xanthate (BX) flotation system. Meanwhile, adsorption tests reveal that with the addition of SS, the adsorption density of BX onto the surfaces of chalcopyrite and galena decrease to 0.0008 and 0.001 mg/g, respectively. These findings indicate that BX on the mineral surface almost completely desorbs. Electrochemical tests further show that in the BX–mineral system, combined with the oxidation peak, BX and mineral react to form CuX2/PbX2. After adding sodium sulfide, the above peak does not appear, indicating that BX does not react with minerals because of the effect of SS. The first-principle calculations based on the DFT further reveals the competitive adsorption mechanism between SS and BX on chalcopyrite (001) and galena (100) surface, thereby demonstrating the significant performance of SS as a removing reagent.

Using amendments is a cost-effective method to soil cadmium (Cd) remediation, whereas knowledge about how different amendments and rates affect remediation efficiency remains limited. This study aimed to evaluate the impacts of different types and amounts of amendments on soil Cd immobilization and its uptake by plants. Biochar (BC), zeolite (ZE), humic acid (HA), superphosphate (SP), lime (L), and sodium sulfide (SS) were applied at three rates (low, medium, and high) ranging from 0.5 to 5%. The concentration of CaCl2-extractable Cd was considerably affected by the amendments, except HA, and the high doses achieved better immobilization effects than the low doses did. The addition of amendments decreased weak acid soluble Cd by 4.1–44.0% but slightly increased the fractions of oxidizable and residual Cd. These amendments (except BC and HA dose of 1%) decreased Cd accumulation in grains by 1.3–68.8% and (except SP) in roots by 16.3–65.5% compared with the control. The SP efficiently immobilized Cd but posed a potential soil acidification risk. Moreover, SS treatment increased the soil electrical conductivity (EC) value and restricted the growth of wheat, possibly due to high-salt stress. BC, ZE, and L exerted significant effects on the reduction in available Cd as the application rate increased. These amendments enhanced Cd immobilization mainly by changing Cd availability in soil and influencing its redistribution in different fractions in soil and root uptake by plants. This study concluded that BC-5%, ZE-1%, and L-0.5% can be used for Cd immobilization in acidic or neutral soils.

Ag2S is an important functional semiconductor material that have received considerable research interest in recent years. The aim of this study was to develop a new method of “green” synthesis of silver sulfide nanoparticles (NPs) using Pleurotus ostreatus mycelium. Silver nitrate and sodium sulfide were used as silver and sulfur precursors of NP production, respectively. Biosynthesized NPs absorption maxima corresponded to 315 and 470 nm. Luminescent spectrum had a wide peak at 520 nm. High resolution transmission electron microscopy (HRTEM) was used to establish the size, morphology and crystal structure of obtained Ag2S NPs. Diameter of synthesized Ag-based NPs was within 10–15 nm, they were spherical in shape. It was found that Ag2S NPs possessed antibacterial activity against Escherichia coli and Bacillus thuringiensis. After treatment of cells the localization of Ag2S NPs was shown (WHERE?) and no significant genotoxic effects were found in plant cells. Due to intense luminescence and nanosize the resulting nanoparticles can be considered as a novel fluorescence probes in cell biology studies.

Rapid decay of photoanode, leakage from sealant, and evaporation of electrolyte are always the major concerns of quantum dot-sensitized solar cells (QDSCs) based on liquid electrolyte. Subsequently, gel polymer electrolyte (GPE) appears as an attractive solution in addition to lower cost, lighter weight, and flexibility. Poly(acrylamide- co-acrylic acid) (PAAm-PAA) is of special interest to act as a polymer host to entrap liquid electrolyte because it provides high transparency, good gelatinizing properties, and excellent compatibility with the liquid electrolyte. In this work, the electrical and transport properties of PAAm-PAA GPE incorporating with water-soluble sodium sulfide were characterized by impedance spectroscopy. An increment of ionic conductivity was observed with the incorporation of ethylene carbonate (EC) and potassium chloride (KCl). The highest room temperature ionic conductivity of PAAm-PAA GPE is 70.82 mS·cm−1. QDSC based on PAAm-PAA GPE with the composition of 1.3 wt% of KCl, 0.9 wt% of EC, 55.3 wt% of PAAm-PAA, 38.5 wt% of sodium sulfide, and 4.0 wt% of sulfur can present up to 1.80% of light-to-electricity conversion efficiency.

Hair waste is one of the solid substances rejected by the leather industry. This waste finds its way into the surroundings causing serious environmental pollution. This hair waste may be utilized for effective extraction of keratin, thereby generating value-added products with numerous applications. Thus we focusing on utilizing red sheep’s hair waste for extracting keratin by the application of different chemical treatments such as sodium hydroxide, sodium sulfide, mercaptoethanol, cysteine, sodium metabisulfite with urea (SMB), and SMB with SDS (SMBS). CD spectrum and FTIR results of the keratin samples indicated a predominance of the helical conformation along with β sheets. SDS-PAGE confirmed the molecular weight of the keratin samples to be in the range of 40–60 kDa. DSC and TGA analysis exhibited the extracted keratin to have a higher denaturation temperature (>200 °C) and thermal stability. The keratin samples obtained using varied chemical treatments were compared in terms of yield, protein content, and cost-effectiveness, and the sample obtained using SMBS was preferred for in vitro studies. It is indicated that keratin extracted using SMBS effectively involved for fibroblast cell growth. Thus, we suggest that these keratin could produce biomaterials that can serve as a valuable material for biomedical applications.

The subject of study was the Safyanovskaya Med company’s acidic underspoil water containing 0.17 g/liter of copper and 1.8 g/liter of zinc (pH 2.8–2.9). The goal was to study and develop a technology of cleaning water of impurities (copper, zinc, aluminum, iron, manganese), accompanied by extraction of copper and zinc in the form of commercial products. Copper extraction by cementation with metallic iron was studied. It was shown that this method could allow extracting 94–95% copper into a concentrate. The role of resolution processes of precipitated copper in cementation was established. To reduce the consumption of iron and to improve the quality of precipitated copper, it is proposed to carry out cementation in a washbox. The copper content in the concentrate was 27–28%, while the specific consumption of iron was 7.0–7.5 kg/kg of copper. During the studies of material composition of copper precipitate, the formation of cuprospinel, goethite, and bassanite phases and the precipitation of basic aluminum sulfates were detected. The extraction of zinc from the solution after copper removal was studied by precipitation with sodium sulfide. As a result, a concentrate was obtained with a zinc content of 49.6–50.9% with extraction of 99%. The process regularities for zinc concentrate dehydration were studied. By optimizing the crystallization conditions of the precipitate, a minimum final cake moisture content of 40–42% was reached. A process flow diagram for acidic underspoil water, including copper cementation and the precipitation of zinc sulfide, was developed. According to this diagram, the mother solution from zinc precipitation should be treated with lime until the pH reaches 10–10.5, followed by slurry settling. As a result, clean water of the following composition is obtained, mg/liter: 0.05 zinc, 0.01 copper, 0.02 aluminum, < 0.02 iron, 0.05 manganese. These values correspond to the quality of drinking water according to GOST R 51232-98.

In this work, the development of a novel sulfur-doped graphene aerogel composite reinforced with carbon fibers (CFs) is presented. Sulfur is entrapped between the graphene nanosheets when GO in the presence of sodium sulfide is reduced hydrothermally to rGO forming a stable hydrogel and an aerogel after freeze-drying. The simultaneous incorporation of CFs improves the mechanical stability of the final composite. The as-prepared composite combines the characteristics of graphene aerogels such as porosity, surface area, chemical inertness with the mechanical properties of CFs and the ability of sulfur to capture lithium, thus providing a material with promising electrochemical properties for lithium-ion battery applications.

An efficient method for the synthesis of N,S-heterocycles with (thio)amide fragments by the catalytic cyclothiomethylation of diamides and dihydrazides of (thio)carbonic acid with H2S, sodium sulfide crystallohydrate, or bis(dimethylamino)methane has been developed.