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This study investigates the effects of sodium sulfide (Na2S) treatment on the mechanical properties of banana fibers, specifically those of the genome Kathali banana type, belonging to the AAB genome, Mysore group banana variety. Banana fibers were treated with varying Na2S concentrations of 2, 4, 6%, and 10%. The analysis encompassed surface morphology changes, tensile strength, fiber linear density, fiber diameter, and Fourier transform infrared (FTIR) spectroscopy examination. Results showed that sodium sulfide treatment significantly reduced the fiber diameter from 168.8 to 54.08 µm, a 67.9% reduction, compared to mechanically extracted untreated fibers. However, single fiber strength decreased from 262.8 gf to 54.77 gf, a 79.5% reduction compared to mechanical extraction. Despite the decrease in single fiber strength, improvements in other mechanical properties, such as increased elongation at break and smoother surface morphology, were observed. The results indicate significant improvements in mechanical performance, highlighting the potential of sodium sulfide (Na2S)-treated banana fibers for various industrial applications, particularly where reduced diameter and enhanced flexibility are advantageous. [ABSTRACT FROM AUTHOR]

Lead sulfide (PbS) on the nanoscale was synthesized via a chemical route at room temperature using lead nitrate {Pb(NO3)2} and sodium sulfide (Na2S). The Na2S was prepared at ~105 °C using sodium hydroxide (NaOH) and sulfur (S) powder. The produced PbS, denoted as Lab-PbS, was compared with a high-concentration PbS phase of galena. The produced Na2S and Lab-PbS were examined using scanning electron microscopy and energy dispersive X-ray spectroscopy for microstructural and chemical analysis. The results confirmed a high-purity PbS compound (>99%) with a nanoscale particle size. The results showed that ultrasonic agitation was vital for obtaining the nanoparticle size of the Lab-PbS. Furthermore, thin films from the synthesized Lab-PbS and galena were successfully thermally evaporated on glass, quartz, and silicon substrates. The formation of nanometric grains was confirmed by scanning electron microscopy (SEM). XRD and FTIR spectroscopy were carried out for the Lab-PbS, galena fine powders, and galena thin films. The average crystal diameter was calculated for the galena thin films and was found to be approximately 26.6 nm. Moreover, the UV–Visible transmission curve was measured for the thin films in the wavelength range of 200–1100 nm in order to calculate the bandgap energy (Eg) for the thin films. The values of Eg were approximately 2.65 eV and 2.85 eV for the galena and Lab-PbS thin films, respectively. Finally, the sintering of the Lab-PbS and galena powders was carried out at ~700 °C for 1 h under vacuum, achieving relative densities of ~98.1% and ~99.2% for the Lab-PbS and galena, respectively. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the reaction mechanism of wulfenite with an aqueous sodium sulfide solution and thereby provide guidance for the sulfidization flotation and sodium sulfide leaching of wulfenite. For this purpose, dissolution/leaching behavior analysis, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscopy (FESEM) were performed. The dissolution/leaching analysis indicated that sodium sulfide can induce the dissolution of PbMoO4. The XRD and Raman spectra results demonstrated that PbMoO4 was replaced by PbS at the wulfenite–sodium sulfide solution interface, and the sulfidized wulfenite particles had a PbMoO4/PbS core–shell structure. The XPS results also indicated the transformation of PbMoO4 to PbS. The FESEM images showed the growth of PbS nanoparticles on the surface of wulfenite and the dissolution pits after treatment with sodium sulfide solution. These findings showed that wulfenite sulfidization proceeds through an interface-coupled dissolution–precipitation mechanism. In the presence of sodium sulfide solution, the less stable PbMoO4 dissolves, and the more stable PbS phase precipitates, both of which are coupled at the wulfenite–sodium sulfide aqueous solution interface. [ABSTRACT FROM AUTHOR]

The demand for nickel, cobalt, and manganese is increasing owing to their critical role in the performance of lithium-ion batteries. Precipitation is simpler to operate than solvent extraction in the separation of metal ions. In this work, precipitation-based procedures were developed to separate Co(II), Mn(II) and Ni(II) from synthetic chloride solutions. Dimethylglyoxime (DMG) was effective in selectively precipitating Ni(II) from the chloride solutions containing Co(II) and Mn(II). Solution pH greatly affected the precipitation of Ni(II) by DMG. In the first procedure, Ni(II) was first precipitated using DMG from solution with initial pH 6 at a DMG/Ni(II) molar ratio of 3, a reaction time of 30 min and then Co(II) was separated from the filtrate by precipitation with Na2S, with optimal conditions being an initial pH of 6, a Na2S/Co(II) molar ratio of 2 and a reaction time of 15 min. In the second procedure, both Ni(II) and Co(II) was simultaneously precipitated with Na2S, leaving Mn(II) in the filtrate. Then the mixed sulfides of Co(II) and Ni(II) were dissolved by using HCl solution containing NaClO as an oxidizing agent. From the leaching solution, Ni(II) was separated by precipitation with DMG. Optimum conditions for the separation conditions were obtained. In both procedures, the separation degree among the three metal ions was higher than 99%. The developed procedures were simple and effective for the separation of the three metal ions compared to solvent extraction. [ABSTRACT FROM AUTHOR]

Abstract Sodium ion hybrid capacitors (SIHC) are emerging as promising next‐generation energy storage devices with high energy/power density. Presodiation is an essential part of SIHC production due to the lack of sodium sources in the cathode and anode. However, in the current presodiation methods, electrochemical presodiation by galvanostatic current charging and discharging requires a temporary half‐cell or a complex reassembling process, which severely hinders the commercialization of SIHC. Herein, in situ synthesized Na2S infiltrated in activated carbon was used as a sodium salt additive for supplying Na+ in SIHC. Due to a low ratio of Na2S additive attributed to high theoretical specific capacity, the fabricated Na2S/activated carbon composite//HC SIHC can show a higher energy density of 129.71 Wh kg−1 than previously reported SIHC on presodiation of cathode additives. Moreover, the designed SIHC shows an excellent cycling performance of 10,000 cycles, which is attributed to the Na2S additive with the advantages of low decomposition potential and no gas generation. This work provides a novel approach for the fabrication of highly efficient Na2S additive composite cathodes for SIHC.

Sodium ion hybrid capacitors (SIHC) are emerging as promising next‐generation energy storage devices with high energy/power density. Presodiation is an essential part of SIHC production due to the lack of sodium sources in the cathode and anode. However, in the current presodiation methods, electrochemical presodiation by galvanostatic current charging and discharging requires a temporary half‐cell or a complex reassembling process, which severely hinders the commercialization of SIHC. Herein, in situ synthesized Na2S infiltrated in activated carbon was used as a sodium salt additive for supplying Na+ in SIHC. Due to a low ratio of Na2S additive attributed to high theoretical specific capacity, the fabricated Na2S/activated carbon composite//HC SIHC can show a higher energy density of 129.71 Wh kg−1 than previously reported SIHC on presodiation of cathode additives. Moreover, the designed SIHC shows an excellent cycling performance of 10,000 cycles, which is attributed to the Na2S additive with the advantages of low decomposition potential and no gas generation. This work provides a novel approach for the fabrication of highly efficient Na2S additive composite cathodes for SIHC. [ABSTRACT FROM AUTHOR]

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The presented scientific research reveals the results of experiments on the precipitation of arsenic in the form of sulfide (As2S3) from the Daridag thermal water using sodium sulfide as a reagent. The main factors impacting the precipitation of the As2S3 compound were determined: the amount of precipitant (Na2S), the ratio of solid and liquid phases (S:L), pH of the initial solution, precipitation time and temperature, also optimal parameters were obtained. According to the results obtained, the yield during precipitation of arsenic tri-sulfide from from thermal water under certain temperature conditions (t=30-450°, pH=1-2; S:L - 1:1000; t = 30-50 min.) were 99.6 %. The properties of the samples were studied by physicochemical research methods (X-Ray, SEM/EDS). X-ray phase analysis showed that the sediment sample obtained under these conditions is X-ray amorphous. The composition and morphology of the obtained sample was confirmed by scanning electron microscopy and spectroscopy (SEM/EDS). [ABSTRACT FROM AUTHOR]

Abstract—The processes of processing copper sulfide concentrate by roasting it with caustic soda without air access with the extraction of the main components (copper, iron, sulfur) were studied. After leaching and filtration of the sinter, sulfur is released into the filtrate in the form of Na2S. At the same time, the release of sulfur dioxide gases into the atmosphere is completely eliminated. [ABSTRACT FROM AUTHOR]

At the Sarcheshmeh Copper Complex, copper and molybdenum minerals float cumulatively. In this step, copper minerals are floated using sulfhydryl collectors and molybdenum mineral is floated with a collector such as Gasoline; Then, in the molybdenum processing plant, copper minerals are depressed using sodium sulfide, and the molybdenite is floated. One of the factors affecting in depress of minerals containing copper and iron is pH. In this study, the appropriate pH value and the best place to add the pH reducing agent were determined to increase the efficiency of the molybdenum flotation circuit. For this purpose, and according to the places where it is possible to add acid operation, the circuit was divided into three parts: rougher stage, third and fifth cleaning stage, and samples were collected from these parts. The results showed that by decreasing the pH in the fifth cleaning stage from 12 to 10.5, copper and iron recovery decreases and efficiency increases. Therefore, the best place to add sulfuric acid, is the fifth cleaning stage. [ABSTRACT FROM AUTHOR]

Biological methanation is driven by anaerobic methanogenic archaea, cultivated in different media, which consist of multiple macro and micro nutrients. In addition, a reducing agent is needed to lower the oxidation–reduction potential (ORP) and enable the growth of oxygen-sensitive organisms. Until now, sodium sulfide (Na2S) has been used mainly for this purpose based on earlier published articles at the beginning of anaerobic microbiology research. In a continuation of earlier investigations, in this study, the usage of alternative reducing agents like sodium dithionite (Na2S2O4) and L-Cysteine-HCl shows that similar results can be obtained with fewer environmental and hazardous impacts. Therefore, a newly developed comparison method was used for the cultivation of Methanothermobacter marburgensis. The median methane evolution rate (MER) for the alternatives was similar compared to Na2S at different concentrations (0.5, 0.25 and 0.1 g/L). However, the use of 0.25 g/L Na2S2O4 or 0.1 g/L L-Cys-HCl led to stable MER values over consecutive batches compared to Na2S. It was also shown that a lower concentration of reducing agent leads to a higher MER. In conclusion, Na2S2O4 or L-Cys-HCl can be used as a non-corrosive and non-toxic reducing agent for ex situ biological methanation. Economically, Na2S2O4 is cheaper, which is particularly interesting for scale-up purposes. [ABSTRACT FROM AUTHOR]

The low-cost Fe(II) reductants used in the leaching of pyrolusite usually cause high concentrations of iron ions in the leaching solution, which are difficult to treat and recover. Herein, a green cyclic leaching process for pyrolusite with recycling and reusing of Fe(II) reductants was developed. Sodium sulfide was introduced to reduce and precipitate iron ions in the leaching solution. Ep-H diagrams show that Fe3+ can be reduced to Fe2+ by S2− and form a precipitate with the high efficiency of 93.09%. Since the main component of the precipitate was ferrous disulfide with reducibility, it was used as a reducing agent for low-grade manganese oxide ores. A total of 97.96% of the manganese was highly reductively leached by the obtained precipitate of 0.28 g·g−1 ore. Furthermore, the leaching efficiency was almost unchanged after five iterations of cyclic experiments. The cyclic leaching process enables the efficient leaching of manganese and the recycling of iron, which provides a green and economic method for the efficient utilization of low-grade pyrolusite resources. [ABSTRACT FROM AUTHOR]

Copyright of Mining & Metallurgy (10057854) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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. [ABSTRACT FROM AUTHOR]

An obtaining of sulfur nanoparticles by hydrothermal method in aqueous solution of L-cysteine, citrate ions, and sodium sulfide is proposed. The optical properties of the obtained sulfur nanoparticles have been studied by UV-Visible absorption and photoluminescence spectroscopies. Transmission and scanning electron microscopies and atomic force microscopy indicate that sulfur nanoparticles are quasi-spherical, their diameter depends on heat treatment time reaching an average size of 28 nm after 8 h of heating at 378 K. The nanoparticles exhibit photoluminescence in the range from 388 to 515 nm depending on the excitation wavelength. The obtained colloid systems have lasting sedimentation stability and high photoluminescence intensity, which make them promising for further wide application. [ABSTRACT FROM AUTHOR]

Under practical conditions, one of the possible solutions to the problem of treatment of hydrogen-sulfide-containing industrial wastewater is the electrochemical oxidation of sulfides. In this work, the model system Fe–NaCl–Na2S–H2SO4–H2O is considered, an experimental setup is constructed, and the electrocoagulation process is studied in a wide (288–308 K) range of temperatures of an aqueous solution of hydrogen sulfide. The optimal ratios between the initial components in the system are determined. The experimental and calculated pH of the solution are found. The system is thermodynamically modeled by minimizing the Gibbs energy, and the concentration distribution of individual molecules and other species (cations, anions) in the solution is characterized. Possible chemical reactions in the system Fe–NaCl–Na2S–H2SO4–H2O during the electrocoagulation of hydrogen-sulfide-containing wastewater are identified. Eh–pH diagrams are constructed to compare the redox potentials of the systems Fe–H2O, Fe–H2O–S, and Fe–NaCl–Na2S–H2SO4–H2O based on the determined concentrations of iron- and sulfur-containing particles in the solution. A calculation formula for the redox potential Eh of the system is obtained. [ABSTRACT FROM AUTHOR]

A coagulation treatment is a separation technology widely used in industries as a pre-treatment step to remove the dissolved organic matter in wastewater. However, the type of coagulant, the optimized dose, and the treatment cost associated with various commercially employed coagulants must be investigated for the treatment of oil and gas produced water. In this study, five widely employed coagulants—ferric chloride, aluminum potassium sulphate, chitosan, sodium sulfide, and magnesium oxide—were tested for the treatment of actual complex oilfield-generated produced water. Water quality parameters such as the total suspended solids (TSS), total dissolved solids (TDS), turbidity, salinity, and pH were assessed for a better understanding of different coagulant activities against the produced water treatment. All the coagulants were efficient for the treatment of produced water. The findings of this study showed that ferric chloride led to the best removal of total solids (74.25%) of all water quality parameters, with treatment costs of USD 4 per m−3 of produced water. The results from this study contribute to the environmentally friendly, broader, and cost-effective application of a coagulation treatment to produced water. [ABSTRACT FROM AUTHOR]

In this study, ammonium phosphate ((NH4)3PO4) was employed to realize improvement by modifying the physical characteristics of the malachite surface, ensuring sustainable flotation throughout the flotation operations, and enhancing the flotation process to be more stable. Furthermore, various techniques, including X-ray photoelectron spectroscopy, were intensely used to investigate the configuration and physico-chemical surface characteristics through micro-flotation experiments, contact angle and zeta potential measurements, and XRD, ToF-SIMS, EPMA, and FTIR spectrum analyses. The FTIR findings showed that new characteristic peaks of -C(=S)-N.H. groups formed and adsorbed on the surfaces of malachite at 1636 cm-1. The -CH2 groups throughout the flotation process, further promoted the attachment of the CH3 ligand to the Cu2+ ion, and the XPS analysis confirmed this. Consequently, it can be concluded that (NH4)3PO4 played a substantial part in the improved recovery rate, as demonstrated and confirmed by the methods carried out in this study. Thus, it was used to modify the physical properties surface before adding Na2S to efficiently enhance malachite floatability and reduce the loss rate of malachite. Regarding the alterations in the physical characteristics which occurred to the malachite surface, and as a consequence of increasing the recovery results of flotation, the malachite sample treated initially with (NH4)3PO4 exhibited micro flotation results with a considerably greater flotation recovery than malachite treated initially with only Na2S ions. [ABSTRACT FROM AUTHOR]

Biological methanation is driven by anaerobic methanogenic archaea, cultivated in different media, which consist of multiple macro and micro nutrients. In addition, a reducing agent is needed to lower the oxidation–reduction potential (ORP) and enable the growth of oxygen-sensitive organisms. Until now, sodium sulfide (Na2S) has been used mainly for this purpose based on earlier published articles at the beginning of anaerobic microbiology research. In a continuation of earlier investigations, in this study, the usage of alternative reducing agents like sodium dithionite (Na2S2O4) and L-Cysteine-HCl shows that similar results can be obtained with fewer environmental and hazardous impacts. Therefore, a newly developed comparison method was used for the cultivation of Methanothermobacter marburgensis. The median methane evolution rate (MER) for the alternatives was similar compared to Na2S at different concentrations (0.5, 0.25 and 0.1 g/L). However, the use of 0.25 g/L Na2S2O4 or 0.1 g/L L-Cys-HCl led to stable MER values over consecutive batches compared to Na2S. It was also shown that a lower concentration of reducing agent leads to a higher MER. In conclusion, Na2S2O4 or L-Cys-HCl can be used as a non-corrosive and non-toxic reducing agent for ex situ biological methanation. Economically, Na2S2O4 is cheaper, which is particularly interesting for scale-up purposes.

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 bismuthinite remained unclear. In this study, the effect of sodium sulfide on the flotation performance of molybdenite and bismuthinite was systemically investigated through micro-flotation tests, bench-scale flotation tests, Fourier transform infrared (FTIR) measurements, adsorption experiments, and X-ray photoelectron spectroscopy (XPS) analyses. Micro-flotation tests indicated that sodium sulfide had excellent depressing effect on the bismuthinite in alkaline condition. The recovery of bismuthinite dramatically decreased from 86.7% to 16.5% with the concentration of sodium sulfide increased to 1 × 10−3 mol/L. By contrast, the depressing effect of sodium sulfide on the flotation of molybdenite was weak. The flotation recovery of molybdenite remained above 60% in the whole pH range tested. Surface analysis using FTIR and XPS analysis revealed that the surface of bismuthinite was covered by hydrophilic sulfide ions after treatment with sodium sulfide, which not only decreased its surface hydrophobicity but also prevented the subsequent adsorption of collector xanthate. While the surface of molybdenite was slightly affected and remained hydrophobic as indicated by high flotation recoveries. Bench-scale flotation tests confirmed that sodium sulfide could be used as an efficient depressant for flotation separation of molybdenite from bismuthinite. The work presented here not only provides a new perspective on the inhibition mechanism of sodium sulfide but also gives a theoretical support for the industrial application of sodium sulfide. [ABSTRACT FROM AUTHOR]

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 depressant for gangue minerals and amine as a collector for zinc minerals previously activated by sodium sulfide. However, the presence of polyvalent ions in aqueous solution can affect the surface properties of the various minerals and consequently, the selectivity of the process. This study evaluated the effect of Zn, Ca, and Mg ions, originated by the solubility of smithsonite and dolomite, on the surface properties of quartz and hematite. Microflotation tests showed the inefficiency of sodium silicate as a depressant for quartz in aqueous solution even when Zn, Ca, and Mg ions were not present. Activation of hematite by Zn ions was observed, impeding the separation of smithsonite and hematite (iron oxide). Results obtained from the microflotation and zeta potential tests were analyzed based on the speciation diagrams of the reagents and ions studied, as well as published studies. [ABSTRACT FROM AUTHOR]

ataclastic rocks of Abu Rusheid area, Southeastern Desert of Egypt, were physically upgraded to obtain with producing a concentrate assaying 29.4% ZrO2, 1.55% Nb2O5, 3.13% RE2O3, 0.9% U3O8, and 0.66% ThO2. The corresponding minerals of these elements in the sample studied include zircon, columbite, samarskite, and uranothorite. Cassiterite is considered as an accessory mineral. The novelty of the suggested procedure is based on selective separation of niobium first from the aqueous liquor of the hydrous oxide cake obtained after alkali breakdown of the concentrate, leaving U, Th, Zr, and REEs in the residue. About 97% of niobium was selectively dissolved under the optimum conditions: weight ratio of concentrate sample to NaOH/KOH mixture 1 : 1.5, fusion time 2 h, and fusion temperature 500°C. This was followed by the recovery of Th, Zr, U, and REEs from the residue. The residue was treated with hydrochloric acid to achieve 98% leaching efficiency. From the two adequately obtained leach liquors, significant products have been prepared. [ABSTRACT FROM AUTHOR]

A zinc smelter in northwestern China obtains sulfur products and hot filter residues after wet smelting and flotation processes. The hot filter residue is smelting solid waste produced by leaching, which is rich in valuable metals such as zinc, gold and iron, and elemental sulfur is the main component, with a content of about 52%. Treating the hot filter residue by alkali leaching can reduce the sulfur content in the hot filter residue, and the generated sodium sulfide combines with other metal elements in the hot filter residue to form sulfide salts, thereby achieving the enrichment of valuable metal elements in the residue and reducing solid waste emissions. The process provides a feasible technical route in terms of economic benefits, process technology, etc., which can realize the efficient enrichment of valuable metals and produce high-performance product sodium sulfide. The sodium sulfide product was used for the coppet-molybdenum separation test and compared with industrial sodium sulfide. The coppermolybdenum separation tost was carried out with the sodium sulfide obtained by high-alkali multiple leaching, and the separation index was excellent, and the separation effect was basically the same as that of industrial sodium sulfide. It can be used in the industrial application of copper-molybdenum separation, providing a technical reference for processing this type of hot filter residue. [ABSTRACT FROM AUTHOR]

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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.

A study of Andean cattle skin was performed to determine the variation of skin substance (SP) produced by lime and sodium sulfide during the Liming and Calera stages using four different treatments (T). According to the ASTM D 2868-17, it is important to characterize the raw materials, followed by the tanning processes until obtaining samples of Wet Blue leather. Besides SP analysis and statistical treatment of the obtained data, sensory and physical-mechanical tests were carried out in the post-tanning stages. The results showed that SP at T1 (2.0% lime-2% Na2S) and T2 (2.7% lime-2% Na2S) produced the highest values; 79.5% and 79.3% respectively; with T3 (3.4% lime-2 % Na2S) and T4 (4.1% lime-2% Na2S) yielding 68.4% and 76.1%, respectively. The statistical analysis of the data evidenced that there is no significant differences between the means of T1 and T2. The results of the physical-mechanical and sensory tests directly relate to the trend of SP consumption in each treatment. The study carried out is aimed to recognize the direct relationship between the skin substance obtained in each treatment and the final product manufactured by the company, referred to the variability of the product to be obtained. [ABSTRACT FROM AUTHOR]

Despite the potential of sodium sulfide (Na 2 S) for phosphorus (P) recovery from iron-phosphate waste, the underlying mechanism regarding its impact on P conversion and product quality has not been well addressed. In this study, the effects of Na 2 S addition on P release and recovery from a chemical-enhanced phosphorus removal (CEPR) sludge during anaerobic fermentation were systematically investigated. The results revealed that the effective mobilization of P bound to Fe (Fe–P) by Na 2 S dominated the massive P release from the CEPR sludge, while the organic P (OP) release was not significantly enhanced during anaerobic fermentation. Due to the rapid reaction of Na 2 S with Fe–P and the prevention of Fe(II)–P precipitation by excess S2−, the Fe–P was decreased by 9.7%, 15.2% and 24.9% at S:Fe molar ratios of 0.3, 0.5 and 1, respectively. After anaerobic fermentation, the released P mainly existed as soluble phosphate (SP), P bound to Ca (Ca–P) and P bound to Al (Al–P). The nitrogen and P contents in the fermentation supernatant significantly increased with higher S:Fe ratios, facilitating the efficient recovery of P as high-purity struvite. However, the increased Na 2 S dosage deteriorated the sludge dewaterability because of the dissolution of hydrophilic extracellular polymeric substances and the looser secondary structure of proteins. Comprehensively considering the P recovery, sludge dewaterability and economic cost, the optimal Na 2 S dosage was determined at the S:Fe ratio of 0.3. These findings provide novel insights into the role of Na 2 S in P recovery as struvite from CEPR sludge. [Display omitted] • Effective mobilization of Fe–P by Na 2 S dominated the release of P from CEPR sludge. • Released P was mainly present in soluble phosphate, Ca–P and Al–P. • Dissolution of hydrophilic EPS deteriorated sludge dewaterability. • Struvite with a purity of 67% was recovered from the sludge fermentation supernatant. • The optimal Na 2 S dosage was determined for P release with better dewaterability. [ABSTRACT FROM AUTHOR]

1,3,5-Triazinane-2,4,6-trithione (TMT) was used for the first time as a sulfidation agent in the flotation of smithsonite. Results showed that 80.5% recovery rate could be obtained in the presence of TMT (5 × 10-5 mol/L) and butyl xanthate (5 × 10-4 mol/L). However, the recovery rate was only 59.4% when sodium sulfide (5 × 10-5 mol/L) was used. Micro-flotation test and contact angle measurement showed that TMT activation was better than sodium sulfide activation. Besides, the contact angle increased from 32.44° (untreated) to 89.58° (treated with TMT), which was significantly higher than 50.2° (treated with sodium sulfide). Fourier Transform Infrared spectroscopy(FT-IR) and Zeta potential test showed the chemisorption of TMT on the smithsonite surface. The results of ICP spectral detection and solution chemistry calculation revealed that Zn3TMT complex precipitates in the smithsonite pulp were formed on the mineral surface at pH 6.5. A hydrophobic film was also formed on the mineral surface after TMT treatment, and more adsorption sites were provided for butyl xanthate. Thus, the adsorption of collector was significantly enhanced. [ABSTRACT FROM AUTHOR]

Anhydrous sodium sulfide (Na2S) is a key component in sodium-sulfur batteries as well as an important chemical reagent. However, anhydrous Na2S is currently prohibitively expensive for applications outside of research labs, and purity is a concern. Herein, we compare the properties of three forms of anhydrous Na2S: (i) commercially supplied, (ii) Na2S produced through dehydration and purification of commercial hydrate flakes (Na2S•xH2O), and (iii) Na2S formed by the reaction of hydrogen sulfide with dissolved sodium alkoxide and recovered through solvent evaporation. Vacuum annealing of low-cost Na2S hydrate at 150°C produced anhydrous Na2S. This dehydrated material retains impurity signatures attributed to polysulfide (Na2Sx) and oxysulfur impurities (SOx) that were also observed in commercially supplied Na2S. Impurity removal typically requires hydrogen reduction at very high temperature (700–900°C), but it is demonstrated here that this can instead be accomplished at 400°C, preventing auto-oxidation and following kinetics well-described by a shrinking core model. The solution-based approach resulted in the direct synthesis of crystalline Na2S anhydride at low temperatures (100°C) without need for further purification. Both approaches presented herein are inherently scalable with materials costs that are one to two orders of magnitude lower than the current price of anhydrous Na2S. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Donors of H2S may be beneficial in treating cardiovascular diseases where the plasma levels of H2S are decreased. Therefore, we investigated the mechanisms involved in relaxation of small arteries induced by GYY4137 [(4-methoxyphenyl)-morpholin-4-yl-sulfanylidene-sulfido-λ5-phosphane;morpholin-4-ium], which is considered a slow-releasing H2S donor. Sulfides were measured by use of 5,5′-dithiobis-(2-nitro benzoic acid), and small rat mesenteric arteries with internal diameters of 200–250 µm were mounted in microvascular myographs for isometric tension recordings. GYY4137 produced similar low levels of sulfides in the absence and the presence of arteries. In U46619-contracted small mesenteric arteries, GYY4137 (10−6–10–3 M) induced concentration-dependent relaxations, while a synthetic, sulfur-free, GYY4137 did not change the vascular tone. L-cysteine (10−6–10–3 M) induced only small relaxations reaching 24 ± 6% at 10–3 M. Premixing L-cysteine (10–3 M) with Na2S and GYY4137 decreased Na2S relaxation and abolished GYY4137 relaxation, an effect prevented by an nitric oxide (NO) synthase inhibitor, L-NAME (Nω-nitro-L-arginine methyl ester). In arteries without endothelium or in the presence of L-NAME, relaxation curves for GYY4137 were rightward shifted. High extracellular K+ concentrations decreased Na2S and abolished GYY4137 relaxation suggesting potassium channel-independent mechanisms are also involved Na2S relaxation while potassium channel activation is pivotal for GYY4137 relaxation in small arteries. Blockers of large-conductance calcium-activated (BKCa) and voltage-gated type 7 (KV7) potassium channels also inhibited GYY4137 relaxations. The present findings suggest that L-cysteine by reaction with Na2S and GYY4137 and formation of sulfides, inhibits relaxations by these compounds. The low rate of release of H2S species from GYY4137 is reflected by the different sensitivity of these relaxations towards high K+ concentration and potassium channel blockers compared with Na2S. The perspective is that the rate of release of sulfides plays an important for the effects of H2S salt vs. donors in small arteries, and hence for a beneficial effect of GYY4137 for treatment of cardiovascular disease.

During the laboratory tests the conditions of arsenic removal from acidic waste solutions of metallurgical enterprise in the form of arsenic trisulfide were determined. The technology based on the reduction of pentavalent arsenic to trivalent state with sodium pyrosulfite solution and following arsenic trisulfide precipitation from acidic solution after treatment with sodium sulfide solution was proposed. The arsenic removal proceeds with mechanical stirring, dosing the calculated amounts of reagents and collecting emissions of hydrogen sulfide. With such treatment, about 95% of arsenic, which was in the initial solution, passes into the precipitate. An enlarged laboratory experiment was carried out and the precipitate with 42.6% of arsenic and 46.9% of sulfur was obtained. The precipitate yield was ~25.7 kg (dry weight) out of 1 m3 of the initial arsenic containing solution. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: The Transient Receptor Potential Ankyrin 1 (TRPA1) channel might play a role in migraine. However, different mechanisms for this have been suggested. The purpose of our study was to investigate the localization and significance of TRPA1 channels in rat pial and dural arteries.Methods: Immunofluorescence microscopy was used to localize TRPA1 channels in dural arteries, pial arteries, dura mater and trigeminal ganglion. The genuine closed cranial window model was used to examine the effect of Na2S, a donor of the TRPA1 channel opener H2S, on the diameter of pial and dural arteries. Further, we performed blocking experiments with TRPA1 antagonist HC-030031, calcitonin gene-related peptide (CGRP) receptor antagonist olcegepant and KCa3.1 channel blocker TRAM-34.Results: TRPA1 channels were localized to the endothelium of both dural and pial arteries and in nerve fibers in dura mater. Further, we found TRPA1 expression in the membrane of trigeminal ganglia neuronal cells, some of them also staining for CGRP. Na2S caused dilation of both dural and pial arteries. In dural arteries, this was inhibited by HC-030031 and olcegepant. In pial arteries, the dilation was inhibited by TRAM-34, suggesting involvement of the KCa3.1 channel.Conclusion: Na2S causes a TRPA1- and CGRP-dependent dilation of dural arteries and a KCa3.1 channel-dependent dilation of pial arteries in rats. [ABSTRACT FROM AUTHOR]

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 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. [ABSTRACT FROM AUTHOR]

Hair removal is necessary before operating on animals with dense hair layers. To provide an appropriate hair removal method and maintain animal welfare, we introduced four commonly used depilation methods—namely, scissors shearing, electric shaving, depilatory cream, and sodium sulfide, and made systematic comparisons, instead of only examining one or two methods, as reported in the past. To further assess convenience and possible effects on skin wound healing, we performed a skin trauma model after depilation in C57BL/6J mice and recorded wound healing time. Meanwhile, the skin tissues around the wound were stained with H&E and Masson. The results showed that the wound contraction rate of the sodium sulfide group was significantly lower than other groups at different points in time. Furthermore, depilatory cream and sodium sulfide methods could induce a topical inflammatory response on the third day after the operation and delay the regeneration of collagen fibers. We concluded that sodium sulfide depilatory has a significant negative effect on wound healing. Depilatory cream is gentler, with mild skin irritation and symptoms of inflammation. The electric shaving method is more convenient and safer, and thus could be the best choice for preoperative depilation.

Wet air oxidation (WAO) is an established technique for reducing the chemical oxygen demand (COD) of refinery sulfidic spent caustic waste. In the present work, the heterogeneous form of the cheap and abundant catalyst ferrous sulfate (FeSO4) was employed for WAO of sodium sulfide. The performance of this catalyst in the oxidative destruction of this model compound is thus far unfamiliar. Kinetic data for the non‐catalytic and catalytic oxidation processes was collected in a batch reactor. For the catalytic process, temperature (T), oxygen partial pressure (PO2) and catalyst concentration (ω) were varied in the ranges 80‐150°C, 0.69‐2.06 MPa and 0.8‐2.4 g/L respectively. Around 94% COD was destroyed within 1 h when feed containing 8 g/L of sulfide was oxidized at T = 100°C, PO2= 0.69 MPa, and ω = 0.8 g/L. First, the data on disappearance of COD were fitted to a power law model and reaction rate constants were determined. The activation energy for the non‐catalytic (91 kJ/mol) and catalytic (50 kJ/mol) oxidation process was found from the temperature dependence of the rate constants. Second, hyperbolic models based on Langmuir‐Hinshelwood (L‐H) and Eley‐Rideal (E‐L) kinetics were used for fitting kinetic data. It was found that the L‐H model suggesting dissociative adsorption of oxygen provided the best fit. In this way, a deep insight into oxidation kinetics of sodium sulfide was provided. [ABSTRACT FROM AUTHOR]

PDS desulfurization method has been applied widely because of effectively solving the problem of hydrogen cyanide poisoning. However, the by-products problem is still a hotspot concerned in whole desulfurization field at present. The reaction between binuclear sulfonated phthalocyanine cobalt (hi-CoPc) and sodium sulfide was studied by the cyclic voltammetry in this paper. The results showed that the oxidation reaction of Na2S and Na2Sx on glassy carbon electrode was an irreversible process controlled by concentration diffusion. And the transformation from S2- to S8 was not a one-step process, hut firstly transformed into the intermediate, Sx2-, then further generated S8. Moreover, it was deduced that only 20% of S2- involved in the reaction was converted into S8. Sx2- had two main existing forms within the range from Sx2- to S92-, and their forms might have influences on the formation rate and production amount of S8. Bi-CoPc could he more readily form the coordination complex with OH- in aqueous solution than in carbonate buffer system, hut the redox reaction of Co+/Co2+ is easier in carbonate buffer system than in aqueous system. Meanwhile, S22- was formed firstly in the reaction between bi-CoPc and Na2S, S22- then could transformed into Sx2- with a longer chain, finally formed S8. It was helpful for us to understand the mechanism of PDS desulfurization, and it also had guiding significance for reducing the formation of by-products. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To investigate the effect of Angelica Sinensis on the model of alopecia areata induced by sodium sulfide and its possible mechanism. Methods: Fifty male KM mice were randomly divided into control group, model group and Angelica Sinensis high, medium and low dose groups, with 10 rats in each group. The model group and the high, medium and low doses of Angelica sinensis were locally coated with 8% sodium sulfide alcohol solution to establish alopecia areata model. The high, medium and low doses of Angelica sinensis were given different doses of Angelica sinensis. The blank control group and the model group were given. The same volume of normal saline was administered once a day for 7 days. The levels of serum interleukin-10 (IL-10) and the number of follicles per unit of field were measured by enzyme-linked immunosorbent assay (ELISA) and hematoxylin-eusin (HE) staining, respectively. The growth was scored. Results: The hair growth score, the number of hair follicles per unit field and the serum IL-10 level in the model group were significantly lower than those in the blank control group (P<0.05). Compared with the model group, the hair growth score, the number of percutaneous hair follicles and the serum IL-10 level in the high, middle and low dose groups were significantly higher than those in the model group(P<0.05). The hair growth score of the medium dose group was significantly higher than that of the high and low dose groups(P<0.05). There was no significant difference between the low dose group and the high dose group, the hair growth score, the number of percutaneous hair follicles and the serum IL-10 level (P>0.05).Conclusions: Oral Angelica has a germinating effect on sodium sulfide-induced alopecia areal mouse model, and the best effect is moderate dose. The growth of hairy root may be related to the increase of serum IL-10 level. [ABSTRACT FROM AUTHOR]

Copyright of Basic Sciences Journal of Textile Universities / Fangzhi Gaoxiao Jichu Kexue Xuebao is the property of Basic Sciences Journal of Textile Universities and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights • The recovery of digenite from heavily oxidized Cu-S ore is of great significance. • The effect of Na 2 S on heavily oxidized digenite and pyrite was studied. • Findings can help understanding the surface properties and sulfidization mechanism of oxidized digenite. • Na 2 S could effectively restore the floatability of heavily oxidized digenite. • The measurements of zeta potential, adsorption, contact angle, and XPS were used. Abstract When valuable digenite is heavily oxidized, it may not respond to the flotation process and remain largely in the tailing with the pyrite. This is problematic because the recovery of digenite from heavily oxidized Cu-S ore is of great significance. In this study, the effect of sodium sulfide on the selective flotation separation of heavily oxidized digenite and pyrite was investigated. The micro-flotation results showed that the floatability of digenite could be effectively restored with the addition of sodium sulfide and sodium butyl xanthate (SBX). However, pyrite showed a poor floatability under the same conditions. Based on this, the flotation separation of artificially mixed minerals was carried out, and a satisfactory result with 51.4% Cu grade and 93.1% Cu recovery could be obtained in the optimized flotation conditions. Then, the sulfidization mechanism of heavily oxidized digenite was discussed in detail through an examination of zeta potential measurements, adsorption measurements, contact angle measurements, and X-ray photoelectron spectroscopy (XPS) analyses. The results indicated that the negatively charged SH− could adsorb on the surface of digenite through chemisorption, and lower the quantity of hydrophilic copper sulfate and oxides/hydroxides on the digenite surface in the presence of SBX, thus significantly increasing the surface contact angle, decreasing the amount of SBX adsorbed to the value observed for unoxidized digenite, and promoting the flotation of heavily oxidized digenite. [ABSTRACT FROM AUTHOR]

The stainless steel pickling residue (SSPR) produced from the stainless steel industries in China contains large amounts of heavy metals such as chromium (Cr) and nickel (Ni). The study found that the hexavalent chromium Cr (VI) was the primary contributor to the leaching of Cr in the toxicity character leaching test. A chemical fixation with sodium sulfide was used to treat the SSPR, and the response surface methodology (RSM) was employed to optimize the process. The results revealed that the sodium sulfide dose and curing time had significant effects on the fixation of Cr. The higher was the sodium sulfide dose, and the longer the curing time, the lower the leaching concentration of Cr would be. The water addition amount had insignificant effect when it was higher than 70%. A dose of 1.2% sodium sulfide on dry mass basis, a water addition of 90–100%, and a curing time of longer than 10 days in the open air could reduce the leaching of Cr to below the beneficial use threshold. The low chemical dose and simple procedures established in this study make this treatment method cost-effective for rendering the SSPR into a nonhazardous and useful material. [ABSTRACT FROM AUTHOR]