Effect Of Sulfur Concentration Research Articles

Plasmonic CuS 2D nanosheets through biologically and environmentally benign template free one-pot synthesis

Our research unveils a novel and eco-friendly technique for the synthesis of emerging two-dimensional Copper Sulfide (CuS) nanosheets through the sulfidation of surface-modified Cu NPs. These fabricated CuS nanosheets exhibit captivating properties such as fluorescence and surface plasmon resonance (SPR) within the near-infrared (NIR) spectrum, rendering them as remarkable candidates for transformative applications in bioimaging and medical sensing.The structural and optical characterization of the material were carried out, and the morphological characterization using SEM and HRTEM shows the formation of 2D CuS as exfoliated long sheets. The investigation projects a simple and cost-effective method to produce 2D Copper Sulfide (CuS) nanosheets. It is formed through a two-step process, including the synthesis of Cu NPs, and transformation of these colloidal Cu NPs into CuS nanosheets through sulfidation. It is found that the concentrations of sulfur and the surface modifying agents like curcumin and ascorbic acid influence nucleation and promote 2D growth of the nanosheets. The effect of sulfur concentration, pH, and surface modifying agents on SPR properties of the Cu NPs were investigated, and the results are presented here. Additionally, our findings indicate that both seed-mediated syntheses and ligand-assisted surface modification leads to the growth of these CuS nanosheets. The cellular studies show that sulfidation reduces the cellular cytotoxicity of Cu NPs. The sample also exhibits excellent stability and biocompatibility, and it is proved to be a promising candidate for photocatalytic, sensing, and biomedical applications, and hence emerges as a multifunctional 2D material.

Effect of sulfur concentration on structural, optical and electrical properties of Cu2CoSnS4 absorber film for photovoltaic devices

In this study, Cu2CoSnS4 (CCTS) films were grown on glass substrates by dipping the sol-gel method. The effect of the thiourea molarity in solution on film properties was investigated. X-ray diffraction (XRD) and Raman Scattering were used to determine the structure of the prepared films. Raman spectroscopic results showed that films with low thiourea molarity have two phases, Cu2-xS and Cu2CoSnS4. As the thiourea molarity increases, this Cu2-xS phase disappears. Optical band gap values found with the help of optical transmittance measurements of the films also decreased from 1.7eV to 1.4eV with increasing thiourea molarity. Morphological properties were examined by Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM). The electrical resistivity of the prepared films is also studied by the two-contact method at room temperature. In general, structural, optical, morphological, and electrical properties of the films were affected by thiourea molarity in solution.

Enhanced visible-light photovoltaic and photocatalytic performances of SnSe1-xSx nanostructures

In this paper, the pristine SnSe and SnSe1 − xSx nanostructures with different concentrations of sulfur were synthesized by a simple, fast, environmentally-friendly, and inexpensive co-precipitation method. Then, the effect of sulfur concentration on the photovoltaic and photocatalytic properties of the nanostructures was investigated. The results show that in presence of sulfur and its concentration change, the crystallite size and the strain of nanostructures change. Also, among nanostructures, S(6%)-doped SnSe nanostructure indicates the significant photocatalytic activity in the degradation of organic dyes and the significant photovoltaic response under visible light. These results can be due to the reducing crystal defects, the reducing electron-hole recombination, and the improving textural characteristics, which lead to reducing the agglomeration of nanostructures and thus increase the absorption of optical photons and more production of electron-hole pairs. Also, the study of photovoltaic properties shows that the highest photocurrent density and lowest diode coefficient belong to S(6%)-doped SnSe nanostructure.

Effect of sulfur amount during post-growth sulfurization process on the structural, morphological and thermoelectric properties of sol-gel grown quaternary chalcogenide Cu2ZnSnS4 thin films

In this work, the CZTS thin films (TFs) have been grown using sol-gel spin coating method on Si substrate. The effect of sulfur concentration on the structural, morphological and thermoelectric properties was investigated using various amounts of sulfur (100–400 mg) during post growth sulfurization process. XRD data evident that the best crystallinity of the CZTS thin film was obtained when the sample was sulfurized using 400 mg amount of sulfur. The vibrational modes of CZTS thin films were observed using Raman spectroscopy with major A1 mode at 331 cm−1 and secondary B(TO) and B(LO) modes at 292 cm−1 and 367 cm−1 respectively. SEM images showed that higher amount of sulfur contents resulted in the compact and smooth surface when compared with the samples sulfurized at lower concentration of sulfur. The thermoelectric properties such as Seebeck coefficient, electrical conductivity and power factor have improved from (249–334 μV/°C), (69–117 S/cm) and (4.28 × 104–1.305 × 103 Wm−1C−2) respectively with increasing the amount of sulfur during sulfurization process. This behavior of thermoelectric properties explained in detail using standard formulas and available literature.

Optical, structural and morphological study of CdS nanoparticles: role of sulfur source

Cadmium sulfide (CdS) nanoparticles were synthesized by using a simple and low-cost home-made hot-injection method at a low process temperature using different sulfur (S) sources. The effects of sulfur concentration on the structural, morphological and optoelectronic properties of the synthesized cadmium sulfide films were studied using a range of characterization techniques: X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FESEM) and ultraviolet–visible spectroscopy. The XRD studies revealed the formation of hexagonal-type cadmium sulfide nanoparticles. The varying morphology dependence on the sulfur source was ascertained from FESEM analysis. The longitudinal optical phonon vibrational modes of cadmium sulfide were assigned in Raman spectra at 300 and 600 cm−1. The bandgap of the cadmium sulfide particles was estimated to be 2·30 eV from Tauc’s plots. Consistent with the experimental results, this study’s first-principles density functional theory calculations predict the bandgap of cadmium sulfide nanoparticles to increase with decreasing sulfur concentration – Cd52S52 (2·38 eV), Cd52S51 (2·52 eV) and Cd52S50 (2·65 eV) – with both the valence and conduction band edges demonstrated to be dominated by sulfur p states.

Effects of sulfur concentration and Marangoni convection on melt-pool formation in transition mode of selective laser melting process

A three-dimensional thermal-fluid model is constructed to investigate the effects of Marangoni convection on the melt-pool formation during the Selective Laser Melting of SS316 powder. The model takes account of the heat-and-mass transfer effects and the melt-pool flow dynamics. In the model, the surface tension gradient in the melt-pool is estimated as a function of the sulfur content of the metal powder based on the reported experimental data. The validity of the model is demonstrated by comparing the simulated melt-pool dimensions under a wide range of laser powers and scanning speeds with the experimental results presented for CL20ES stainless steel powder in the literature and SUS420 stainless steel powder obtained in the present study. The results show that besides the conduction mode, in which the melt-pool formation is dominated by thermal conduction, and the keyhole mode, in which the melt-pool formation is determined mainly by the recoil pressure, an additional transition mode exists between these two modes, in which the melt-pool formation is driven mainly by the Marangoni convection effect. In particular, for stainless steel powders with a higher sulfur content, an inward Marangoni flow occurs, which results in a deeper melt-pool and a lower porosity of the built part.

Effect of sulfur concentration on structural, optical and electrical properties of Cu2FeSnS4 thin films for solar cells and photocatalysis applications

Quaternary chalcogenide Cu2FeSnS4 (CFTS) thin films were successfully elaborated by spray pyrolysis technique on glass substrates using different thiourea concentrations (4, 5, 6 and 7.10−2M) as sulfur source. The chemical composition, morphological, structural, optical and electrical properties were investigated using respectively dispersive X-ray spectrometry (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, spectrophotometer and Hall Effect measurements. XRD and Raman spectroscopy revealed that CFTS thin films synthesized at thiourea concentration [S] = 6.10−2M grows with a pure and good crystalline quality. CFTS thin layer crystallized into the stannite structure with the preferred orientation (112) plan. The average grain size reaches a maximum value about 41 nm at [S] = 6.10−2M. The obtained CFTS stoichiometric ratio was Cu:Fe:Sn:S = 2,25/1/0,91/4,08 which is close to the theoretical ratio 2:1:1:4. Optical properties present a high absorption coefficient value equal to 8 104 cm−1, with an estimated band gap value 1,05 eV. This work demonstrates also that electrical resistivity was about 0,46 Ω cm at room temperature and has been decreased to a minimum value of 0,014 at 80 °C. All these experimental results make sprayed CFTS thin film synthesized at [S] = 6.10−2 M as a promising absorber layers in solar devices. Methylene Blue dye under sun illumination has been used to test to photocatalytic activity of optimum CFTS thin film. A value of photo-degradation near 76% of MB dye has been obtained for 4 h duration. This result show that CFTS thin film synthesized at [S] = 6.10−2 M is a good candidate for photocatalysis applications.

Bioleaching of heavy metals from pig manure with indigenous sulfur-oxidizing bacteria: effects of sulfur concentration

The purpose of this work was to study the sulfur concentration on bioleaching of heavy metals from pig manure employing indigenous sulfur-oxidizing bacteria. Also, the variations in physicochemical properties of pig manure before and after bioleaching were investigated. The results showed that sulfur concentration significantly affected the rate of acidification, sulfate production and metal solubilization during pig manure bioleaching process. A Michaelis–Menten type equation was utilized to interpret the relationships between sulfur concentration, sulfate production and metal solubilization in the bioleaching process. The rates of metal solubilization during pig manure bioleaching were well described by a first order kinetic equation related to time. After 12 days of bioleaching, 93%–97% of Zn, 96%–98% of Mn and 48%–94% of Cu were leached out from pig manure, respectively. The metals remaining in the pig manure residual were mainly existed in stable forms. In addition, elemental analysis showed that bioleaching process could significantly modify the dewaterbility and organic composition of pig manure. However, fertility analysis found that 9.0%–19.1% of nitrogen, 68.5%–71.0% of phosphorus, 76.5%–78.8% of potassium and 47.5%–49.4% of the total organic carbon (TOC) were lost from pig manure in the bioleaching process. Therefore, bioleaching process used in this study could be applied to remove heavy metals effectively from the pig manure, but more detailed studies need to be done to decrease the nutrients loss from pig manure.

The Effect of Sulfur Concentration in the Metal on the Mass Transfer of Phosphorus in Bloated Metal Droplets

In Basic Oxygen Steelmaking, metal droplets created by the impact of the oxygen jet will swell due to internal decarburization when they react with oxidizing slag in the emulsion zone. In this study, the dephosphorization behavior of bloated metal droplets containing different sulfur concentrations is investigated in the temperature range from 1813 to 1913 K using X‐ray fluoroscopy coupled with constant volume pressure change measurements and chemical analysis of quenched samples. The results show that higher sulfur droplets (>0.017 wt%) have a much longer incubation period for swelling than those with lower sulfur (<0.017 wt%). Due to this different swelling behavior, the dephosphorization rate for high sulfur droplets is found to be not heavily affected by the experimental temperature compared to the case of lower sulfur droplets. Employing a mixed control model including mass transfer and chemical reaction, the effect of temperature on dephosphorization kinetics is further discussed. The mass transfer coefficient in the metal, km, is found to increase slightly with increasing temperature for droplets with 0.021 wt% sulfur. It is also found that lower rates of CO formation result in less stirring in the droplet and lower mass transfer rates of phosphorus for high sulfur droplets.

Effect of sulfur concentration on the properties of tin disulfide thin films by nebulizer spray pyrolysis technique

Influence of sulfur concentration variation on the physical and chemical properties of nebulizer spray pyrolysis deposited SnS2 thin films are investigated. The SnS2 thin films were coated onto glass substrate at 325 °C by changing sulfur concentration as 0.8, 0.9 and 1.0 M. Sulfur concentration dependent micro-structural, surface morphological, optical and electrical characteristics of the films were studied using X-ray diffraction, Raman analysis, scanning electron microscope, atomic force microscope, UV–Vis spectroscopy, photoluminescence spectroscopy and Hall Effect measurement, respectively. X-ray diffraction measurements demonstrated the growth of crystalline SnS2 films of hexagonal structure with preferred orientation along (002) plane. Scanning electron microscopic study revealed needle shape and basket knitting shape morphology of deposited films. The films showed direct band gap ranging from 2.02 to 2.18 eV depending on sulfur concentration. Hall measurement revealed the conductivity and mobility ranging from 10−3 to 10−2 (1/Ω-cm) and 1.4 × 102 to 3.01 × 102 (cm2/V s) respectively.

Effect of sulfur concentration on structural, elastic and electronic properties of molybdenum sulfides from first-principles

Molybdenum sulfides (Mo-S) have been the topic of current interest owing to the interaction between the hydrogen and unsaturated sulfur atoms. However, the correlation between the S concentration and structure, and relevant properties are not well understood. By using the first-principles calculations, we investigated the influence of S concentration on the structural stability, elastic and electronic properties of Mo-S sulfides. The formation enthalpy of Mo-S sulfides under high pressure is calculated. The previous unreported crystal structure of MoS with VS-type structure (space group: Pmcn, No. 62) is predicted. The convex hull indicated that MoS with hexagonal structure is more thermodynamic stability than that of other Mo-S sulfides. It is found that the structural stability is attributed to the charge contribution of S-3s state and S-3p state with increasing S concentration. The elastic properties of Mo-S sulfides are directly related to the S concentration. The bulk modulus of Mo-S sulfides decreases linearly with increasing S concentration. Finally, it is concluded that Mo-S sulfides exhibit metallic behavior except for MoS2.

Effect of anionic concentration on the structural and optical properties of nanostructured ZnS thin films

Nanostructured Zinc Sulfide (ZnS) thin films with wurtzite structure were prepared by chemical spray pyrolysis method at low temperature. The effect of sulfur concentration on the structural and optical properties of ZnS thin films was studied. The films were analysed by x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), UV–Vis spectroscopy and photoluminescence (PL). Nano grain formation of ZnS was observed from XRD and SEM. Variation in band gap of different films is in agreement with size effects. But there is a red shift in the band gap of these films compared to bulk ZnS. This is due to band tailing effect experienced by the films due to the presence of large number of defects which was verified by PL spectrum. The overall emission was blue in colour for all the films and it was confirmed by Commission International d'Eclairage (CIE) diagram.

Effect of sulfur concentration on diamond crystallization in the Fe–C–S system at 5.3–5.5 GPa and 1300–1370°C

The paper presents results of experiments aimed at diamond synthesis in the Fe–C–S system at 5.3–5.5 GPa and temperatures of 1300–1370°C and detailed data on the microtextures of the experimental samples and the composition of the accompanying phases (Fe3C and Fe7C3 carbides, graphite, and FeS). It is demonstrated that diamond can be synthesized after temperatures at which carbides are formed are overcome and can crystallize within the temperature range of 1300°C (temperature of the peritectic reaction melt + diamond = Fe7C3) to 1370°C (of thermodynamically stable graphite) under the appearance experimental pressure. The possible involvement of natural metal- and sulfur-bearing compounds in the origin of natural diamond is discussed.

Impact of sulfur concentration on morphological, optical, electrical and thermoelectrical properties of nanostructured MoO3 thin films

We have investigated the effect of sulfur concentration ([S]/[Mo] = 0–10 at.%) on nanostructural, optical and electrical properties of MoO3 thin films grown on glass substrate by spray pyrolysis technique. X-ray diffraction analysis showed that the films were crystallized with mixed structures of MoO3 orthorhombic and MoS2 hexagonal structure. According to FESEM images, the studied films have a sponge-type structure on the order of nanometers. Optical measurements revealed that two distinct inflexions indicative two transitions correspond to MoO3/MoS2 phases in agreement with the XRD analysis. The Hall effect and thermoelectric measurements have shown p-type conductivity, and the free hole density increases with increasing sulfur to molybdenum ratio, in agreement with reflectance spectra of the layers. The obtained value of Seebeck coefficient for MoO3 film with [S]/[Mo] ratio of 8 at.% was as high as 169 μV/K.

Kinetics of heavy metal biosolubilization from electroplating sludge: effects of sulfur concentration

The removal of heavy metals from industrial sludge through biosolubilization using sulfur-oxidizing bacteria has been shown to be a promising technology, but the process with surplus concentration of sulfur causes re-acidification of the treated residues and creates environmental issues. Thus, the study for investigating the effect of sulfur concentration on the heavy metal biosolubilization system, with an emphasis on optimizing the sulfur concentration, is of immense importance. In this study, the experiments to investigate the effect of sulfur concentration on the performance of biosolubilization were carried out using 2–10 g/L elemental sulfur on heavy metal-laden electroplating sludge (50 g/L). The sludge-acclimatized, sulfur-grown Acidithiobacillus ferrooxidans isolate was used as sulfur-oxidizing bacteria. For the type of sludge used in this study, high pH reduction, short lag phase, and high heavy metal solubilization efficiencies were obtained in the treatment with 6 g/L sulfur. The kinetic study showed that the rate constant values of heavy metal solubilization were relatively high while using sulfur concentration of 6 g/L. The analysis using shrinking core model of fluid–particle reaction kinetics explicated that chemical reaction step controls the rate of heavy metal biosolubilization. The study provides an optimized strategy to design an efficient biosolubilization system for anticipated energy source.

Effect of sulfur concentration on microbial removal of arsenic and heavy metals from mine tailings using mixed culture of Acidithiobacillus spp.

The effects of elemental sulfur, an energy source for bacterial growth, on the removal of As and heavy metals from mine tailings collected from a flotation plant in the Philippines were investigated using a mixed culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. The fractionation of As and heavy metals in the mine tailings before and after bioleaching was also studied. Leaching tests were conducted in duplicate for 500h, at 30°C, and 200rpm, with six sulfur concentrations (0%, 0.1%, 0.2%, 0.5%, 1%, and 2%, w/v). The laboratory results showed that 92.0% Mn, 45.0% Cu, 67.2% Zn, 42.4% As, and 47.7% Fe could be removed from mine tailings after 500h at 0.5% elemental sulfur concentration. The results also indicated that 0.5% elemental sulfur concentration was the best for bacterial activities and metal removal from mine tailings under the chosen laboratory conditions. In sequential extraction results, it was observed that the bioleaching process also affected the changes of metal distribution in the final residue. Most of As and heavy metals was found to occur as stable forms in the residues after bioleaching.

初期凝固シェルへの介在物捕捉に及ぼす溶鋼中［S］の影響

In order to clarify the effect of compositions on the surface quality of ultra low carbon steel slabs, a model experiment investigating the effect of compositions on entrapment of inclusions was performed using molten steel with various concentrations of S, which is a surface active element between molten steel and inclusions, while varying the velocity of the molten steel flow at the solidification interface to obtain clear changes in the interfacial tension between the inclusions and the molten steel.As a result, entrapment of inclusions was enhanced with increasing S concentration, and the effect of S concentration on entrapment of inclusions depended on the velocity of the molten steel flow at the solidification interface.In the case of a large inclusion, the effect of S concentration on entrapment of inclusions is considered to be affected by the various thicknesses of the concentration boundary layer.

The Effect of Sulfur Concentration in Liquid Iron on Mineral Layer Formation During Coke Dissolution

The effects of sulfur concentration in liquid iron on mineral layer development between coke and iron as coke dissolves in a 2 mass pct carbon-iron liquid have been investigated at 1773 K (1500 °C). The initial sulfur in iron concentrations used ranged from 0.006 to 0.049 mass pct. Key findings include that the two-stage dissolution behavior exhibited in the carbon transfer from coke to iron, as reported in a previous study by the authors, at low initial sulfur in iron contents, was also apparent at the higher values used in this study. This two-stage behavior was attributed to a change in the mineral layer density as a result of changes in mineral morphology at the interface. In addition to confirming the two-stage behavior of the carbon-transfer kinetics at the higher sulfur concentration in iron levels, after a period of time, a solid calcium sulfide layer formed on the mineral layer. The sulfide layer formed after approximately 40 minutes, and the proportion of sulfide in the mineral layer increased with increased experimental time and initial sulfur concentration in iron. It was usually found at the iron side of the mineral layer and was associated with calcium-enriched calcium aluminates. Thermodynamic analysis of this layer confirmed that the sulfide is stabilized as the mineral layer is enriched by calcium.

Effect of Sulfur Concentration on the Morphology of Carbon Nanofibers Produced from a Botanical Hydrocarbon

Carbon nanofibers (CNF) with diameters of 20–130 nm with different morphologies were obtained from a botanical hydrocarbon: Turpentine oil, using ferrocene as catalyst source and sulfur as a promoter by simple spray pyrolysis method at 1,000 °C. The influence of sulfur concentration on the morphology of the carbon nanofibers was investigated. SEM, TEM, Raman, TGA/DTA, and BET surface area were employed to characterize the as-prepared samples. TEM analysis confirms that as-prepared CNFs have a very sharp tip, bamboo shape, open end, hemispherical cap, pipe like morphology, and metal particle trapped inside the wide hollow core. It is observed that sulfur plays an important role to promote or inhibit the CNF growth. Addition of sulfur to the solution of ferrocene and turpentine oil mixture was found to be very effective in promoting the growth of CNF. Without addition of sulfur, carbonaceous product was very less and mainly soot was formed. At high concentration of sulfur inhibit the growth of CNFs. Hence the yield of CNFs was optimized for a given sulfur concentration.

Bioleaching of heavy metals from anaerobically digested sewage sludge

The effects of sulfur concentration, initial pH of the sludge and sludge solid content on metal bioleaching were examined using anaerobically digested sewage sludge procured from a typical sewage treatment plant in Delhi, the capital city of India. Experiments on effect of sulfur concentration were carried out using 0–4 g L−1 of elemental sulfur to optimize the concentration of elemental sulfur for efficient bioleaching. For the type of sludge (20 g L−1 solid content) used in the present study, 2 g L−1 of elemental sulfur was found sufficient in metal bioleaching in the following order: Zn 86%, Cu 71.5%, Mn 70%, Ni 58.3% and Cr 43.8%. Changes in pH, sulfate concentration and oxidation-reduction potential (ORP) as a function of time were experimentally monitored. A rapid change in the above parameters took place in 4–6 days followed by a slow change until the 10th day. The change in pH with time was observed to vary at different initial pH values (pH 7 to pH 3) of the sludge; however, there was not much difference in the final pH achieved and final metal solubilization which ranged from: Cu 83.6–94.2%, Ni 27.7–29.8%, Zn 89–94.8%, Mn 67.5-79% and Cr 34.1–44.1% The results of the present studies strongly indicate that using 2 g L−1 elemental sulfur, indigenous sulfur oxidizing microorganisms can bring down pH to a value needed for significant metal solubilization. Also, bioleaching can be carried out successfully over a wide range of initial pH values of the sludge. Further, at higher sludge solid concentration than 20 g L−1, lower metal solubilization was achieved due to the buffering capacity of the sludge.