Interaction Of Sulfur Research Articles

Controllable preparation, formation mechanism and photocatalytic performance of copper base sulfide nanoparticles

In this paper, copper base sulfide nanoparticles (Cu2S, CuS, CuO/Cu2O/Cu2S, Cu2S/CuS, CuS/S) were synthesized in polyethylene glycol (PEG)-400 by a one-step method and by tuning the molar ratios of Cu:S (1:0.1–1:3) with copper acetate and sublimed sulfur as sources. The interaction of elemental sulfur with copper ion in PEG was analyzed in detail to elucidate the formation mechanism. With the change of the molar ratio of copper to sulfur, the products exhibit a variety of composition, morphology and size. When the molar ratio of copper to sulfur is 1:1, the product is CuS nanoflakes with particle size of 200–300 nm and thickness of 30 nm. The CuS nanoflakes with a smaller band gap value of 2.01eV can photodegrade 96% (48 mg/g) of rhodamine B (RhB) in 5 min in the presence of H2O2. This route is simple, environmentally friendly and it offers a more promising way to prepare different morphologies and compositions of Copper Base Sulfide Nanoparticles (CBSN).

Desulfurization of Dibenzothiophene from Model Oil by Aluminum Ammonium Sulfate/Urea (Alum) Ionic Liquid Analogue

Petroleum is the most important source of energy which is required to be free of sulfur. Ionic liquid analogue was used to desulfurize Model oil at several conditions including different concentration of dibenzothiophene (DBT), time of extraction, temperature and ionic liquid analogue to Model volume ratios. The cheap and easy made ionic liquid analogue is a mixture of 1:5 mole ratio of Aluminum ammonium sulfate.12H2O: Urea (Alum).The desulfurization was followed by ATR-IR, GC-MS. Aluminum salt ionic liquid analogue was found to have more than 90% removal of DBT from its mixture with decane (Model). The process in the Alum solvent was attributed to combination of an absorption and possibly oxidation of DBT through interaction of sulfur with the oxygen of sulfate group of the ionic liquid analogue when the IR bands of sulfate and hydrogen bond of ionic liquid analogue were influenced strongly by this interaction. The removal of dibenothiophene was more effective at 30 oC and 10 min than higher temperature and longer time.

Agronomic efficiency of sulfur sources and interaction of sulfur with micronutrients

Fertilizer utilization efficiency and nutrient interactions during uptake directly influence grain yield. The objective of this work was to evaluate the agronomic efficiency of sulfur (S) sources on yield and the interaction of S with micronutrient concentrations in soybean. The study involved four S rates (0, 50, 100, and 200 mg kg−1) applied from five sources (S-phosphogypsum, S-Niquelândia rock, S-Araripina rock, S-Grajaú rock, and S-Sulfurgran [90% S0 + 10% bentonite]) in two soil types with different clay concentrations (Typic Ultisol and Typic Oxisol). The efficiency of S sources and rates was determined based on two indices: agronomic efficiency index (AEI) and Sulfurgran equivalent (SEq). The optimal AEI and SEq were observed from the S-Grajaú rock and S-phosphogypsum sources, with the highest values ​​in the Typic Oxisol, while the S-phosphogypsum displayed the highest S recovery rate regardless of soil type. The S sources and rates did not influence the B, Cu, Fe, Mn, and Zn concentrations in leaves and grains.

Response of Sorghum (Sorghum bicolor L. Moench) Genotypes to Different Levels of Agricultural Sulfur

A field experiment was conducted in agricultural research station which is located at Al-Qurna district, 75 km north of Basrah governorate during the autumn season 2018. The aim was to study the effect of agricultural sulfur (0, 3, 6 and 9 t S.ha-1) on growth and yield of three sorghum genotypes (Inkath, Rabeh and Kafier2). The experiment was conducted as randomized complete block design in a factorial arrangement with three replications. The results showed that there were significant differences among the genotypes. The genotype kafier2 gave the highest average of plant height of 171.5 cm while the genotype inkath gave the highest weight of 1000 seed (25.59 gm), grain yield (3.97 t.ha-1). Genotype rabeh produced highest average of leaf area index and number of grain head of 3.10 and 1994.41 grain.head-1 respectively. The agricultural sulfur showed significant effect on most studied traits of sorghum (plant height, leaf area index, grain head, weight of 1000 grains and grain yield). The addition of agricultural suffer up to 9 t. ha-1 increased grain yield and produced 5.80 t.ha-1. The interaction of genotypes and agricultural sulfur showed a significant effect on some traits of growth and grain yield. The genotype inkath supplied with 9 t.ha-1 of agricultural sulfur resulted in highest grain yield of 5.80 t.ha-1, while the genotype rabeh supplied with 6 t.ha-1 of agricultural sulfur gave the highest average of leaf area index (3.54) and number of grains head (2106.33 grain.head-1).

Sulfur controlled cadmium dissolution in pore water of cadmium-contaminated soil as affected by DOC under waterlogging

Cadmium (Cd) precipitation and dissolution in pore water is associated with dissolved organic carbon (DOC)-induced reduction-oxidation of sulfur (S) under waterlogging and is vital for controlling the bioavailability in paddy soil. A 120-day soil incubation experiment, including application of sulfur (S, 30 mg kg−1) and wheat straw (W, 1.0%) alone or in combination (W + S) into Cd-contaminated paddy soil under waterlogging, was conducted to investigate the dynamic of dissolved Cd and its relationship with DOC, S2−, Fe2+, pH, Eh and pe + pH in soil pore water. The results showed that the lowest dissolved Cd concentration was observed in the W + S-treated soil pore water among all treatments when the soil Eh remained at lower values during the period of 15–60 days of incubation, which could be attributed to CdS precipitation and/or co-precipitation of Cd absorbed by FeS2 because of the reduction in sulfur. The application of S resulted in a Cd rebound in the pore water irrespective of W addition when the Eh began to increase from its lowest values during the period of 45–75 days of incubation, and SOB genera were observed in the S added soil. This could be attributed to re-dissolution of the precipitated Cd in soils under the SOB-driven oxidation of sulfide such as CdS and FeS2. In conclusion, DOC-driven reduction-oxidation of sulfur controls Cd dissolution in the pore water of Cd-contaminated paddy soil under waterlogging conditions. Further studies are required to investigate the interaction of sulfur and SOM-induced DOC on Cd bioavailability in rice-planted paddy soils.

Hydrometallurgical Treatment of Elemental Sulfur in Spent Catalysts by Aqueous and Nonaqueous Solutions at Low Temperature

ABSTRACTSpent catalysts generated from petroleum refining contain some valuable metals and their surface is covered by elemental sulfur. During the recovery of valuable metals in the spent catalysts, the sulfur present in the surface of spent catalyst should be treated. In order to develop an environment-friendly process to treat these spent catalysts, the dissolution behavior of elemental sulfur between nonaqueous solvents (octanol/decanol) and NaOH solution was compared, which has never been reported. Sulfur was dissolved in decanol and octanol and the dissolved sulfur was recrystallized as the solution cooled to room temperature. The optimum treatment conditions of sulfur in nonaqueous solvents were obtained. The interaction of sulfur with these nonaqueous solvents was analyzed through a radical mechanism and its mechanism was first proposed in the current work. Unlike the treatment of sulfur with decanol and octanol, the dissolution of sulfur in NaOH solution is assumed to occur through oxidation/reduction reaction and the optimum conditions were obtained. The application of these methods is expected to have a meaningful impact on the recovery of sulfur from spent catalyst materials.

Ab initio Computer Simulation of the Energy Parameters and the Magnetic Effects in Ternary Fe–X–C (X = Si, P, S, Cr, Mn) Systems

The equilibrium structure and the properties of ternary Fe–X–C (X = Si, P, S, Cr, Mn) systems are studied by ab initio simulation using the WIEN2k software package. The calculations are performed by the full-potential linearized augmented plane wave method (FLAPW) with allowance for the generalized gradient approximation (PBE-GGA). These methods are most accurate in terms of the density functional theory. The magnetic structure of Fe–X–C alloys and the interaction between carbon and impurity atoms at various distances are analyzed. Repulsion is detected between impurity silicon, phosphorus, and chromium atoms and carbon atoms in all three coordination shells, which significantly increases the dissolution energies of these impurities. Analogous repulsion for the first two coordination shells is also observed for the interaction of sulfur and carbon atoms, and weak attraction between these atoms appears in the third coordination shell. The interaction of carbon with manganese is characterized by attraction in the first two coordination shells, and the dissolution energies of both manganese and carbon decrease.

Fate of sulfur in chemical looping combustion of gaseous fuels using a Perovskite oxygen carrier

In the present study, the influence of sulfuric fuel impurities on CLC is investigated in a 120 kWth chemical looping combustion pilot unit consisting of two interconnected circulating fluidized beds. An in industrial scale produced perovskite type CaMn0,775Mg0,1Ti0,125O3-δ, called C28 has been used as oxygen carrier. The oxygen carrier is manufactured by spray drying method. As fuel natural gas from the grid, originally without sulfur, is used. To investigate the influence of sulfur, H2S has been added to the fuel stream up to a concentration of 3000 ppmv. The measurements have been performed at operating temperatures of 950 °C. For closing the mass balance of sulfur, the exhaust gas streams of air and fuel reactor are analyzed against H2S and SO2. To investigate potential interaction of sulfur with the particles, SEM, ICP-OES, XRF and XRD analysis have been carried out with solid samples of the oxygen carrier particles.The general fuel conversion performance of the C28 oxygen carrier is negatively affected by the H2S impurities in the fuel feed. In almost all investigated samples crystalline phases of MgS was formed due to H2S. No sulfur was detected in the air reactor. During all experiments no H2S slip was observed. A regeneration during CLC operation after switching off the sulfur feed was not possible.

Electrocatalysis of Ruthenium Nanoparticles-Decorated Hollow Carbon Spheres for the Conversion of Li2S2/Li2S in Lithium-Sulfur Batteries.

Controlling "polysulfide dissolution" and pacifying "polysulfide shuttle" hold the key in developing a lithium-sulfur battery with superior electrochemical performance. Further, exploration of the concept of electrocatalysts plays a significant role in enhancing the electrochemical reversibility of polysulfides in lithium-sulfur battery. Herein, ruthenium nanoparticles-decorated porous, hollow carbon spheres have been successfully prepared and deployed as electrocatalyst as well as sulfur host in the lithium-sulfur battery assembly. Interaction of sulfur with ruthenium nanoparticles has been explained with appropriate electroanalytical and electrochemical characterization techniques. We observe that lithium-sulfur battery containing C-Ru-S cathode with a fixed sulfur loading exhibits a significantly improved capacity of 1200 mA h g-1 at C/10 current rate for 100 cycles. Volume expansion-related issues are found to get addressed by the hollow structured carbon spheres, and the electrocatalytic activity will improve the reaction kinetics of the conversion of Li2S2 to Li2S and vice versa.

Interaction of Biogeochemical Sulfur and Carbon Cycles in Marine Basins by the Example of the Black Sea

The interaction of biogeochemical sulfur and carbon cycles in water bodies has been studied by the different authors and methods, including the use of 35S and 14C radioactive tracers. The main reactions of sulfur and carbon interaction by the example of the Black Sea (sulfate reduction, methanogenesis, aerobic and anaerobic methane oxidation) are considered. Based on the experimental radioisotope data, the annual microbial production of H2S and CH4 in the water column of the Black Sea is estimated. The average annual production of CH4 is 3.8% of the annual production of H2S. The share of migration methane from the bottom sediments (seeps, mud volcanoes, etc.) is approximately 2% of the total dissolved methane pool.

Fate of sulfur in chemical looping combustion of gaseous fuels using a copper-based oxygen carrier

The development of the chemical looping combustion technology for gaseous fuels has reached a point where it has been demonstrated in several pilot units for several thousands of hours using a variety of oxygen carriers. So far, a lot of experimental work was focused on fuel conversion performance and life time of oxygen carrier particles. In addition to the general performance of an oxygen carrier regarding fuel conversion, it is of special interest how it interacts with fuel impurities or contaminants like sulfur. Here, it is not only of interest if and how impurities affect fuel conversion performance, but also in which composition and in which reactor stream (air reactor or fuel reactor) they leave the CLC system. This knowledge is of great importance when it comes to the requirements of exhaust gas treatment facilities in large scale units.In the present study, the fate of sulfur in chemical looping combustion has been investigated in a 120 kWth pilot unit consisting of two interconnected circulating fluidized beds using a copper based oxygen carrier prepared by impregnation on an inert alumina support. Natural gas from the grid, originally without sulfur, was used as fuel. To investigate the influence of sulfur, H2S has been added to the fuel stream up to a concentration of 2000 ppmv. In order to close the mass balance of sulfur, the exhaust gas streams of air and fuel reactor are analyzed against H2S and SO2. Further, solid samples of the oxygen carrier particles were taken on a regular basis to investigate potential interaction of sulfur with the particles.The contribution shows how sulfur affects the general fuel conversion performance of the oxygen carrier as well as how much H2S is converted to SO2 and in which exhaust gas stream it leaves the reactor system. Measurements were performed for several temperatures in the range of 800–850 °C.

Lack of Mutagenic Activity of Sulfur Nanoparticles in Micronucleus Test on L5178Y Cell Culture

The nature and physicochemical characteristics of nanomaterials affect their biological activity. Sulfur microparticles and sulphur nanoparticles have different levels of activity against bacterial, fungal, and animal cells. The cytotoxicity and genotoxicity of sulfur nanoparticles (SNPs) of about 70 nm in size were examined on the L5178Y mouse lymphoma cell culture. The concentration of SNPs causing 50% cell death is 0.078–0.312 mg/mL. The micronucleus assay revealed no mutagenic properties of SNPs. Metabolic activation of SNPs by the rat liver microsomal fraction does not affect the toxicity. It is assumed that the mechanism of cytotoxic action is associated with the interaction of elemental sulfur with sulfhydryl groups of molecules inside the cell.

Sulfur cathode material conductivity improving by carbons admixture: technology and characterization

Sulfur (S) is announced as future cathode material with a theoretical specific capacity of 1672 mAh/g,∼5 times higher than those of traditional cathode materials based on transition metal oxides or phosphates. S based battery is partly limited by the problems of low electrical conductivity of sulfur, dissolution of polysulfides in electrolyte and volume expansion of sulfur during discharge. The high effort to find materials to overtake these disadvantages is leading to conductive materials like S. The carbons are well known for very good conductivity along the graphene layers. For this purpose, 2 types of carbons were tested using mechanofusion milling process to create interaction of sulfur and carbon as two inorganic materials. Conductivity was tested, and improvement was shown. To solve problems with dissolution of polysulfides in electrolytes the intercalation of sulfur to clay interlayer space was designed.

Impurity State of Transition Group Elements in the Silicon Lattice in the Process of Their Interaction with Sulfur

On the basis of comparative analysis of electrical properties of silicon doped with sulfur and nickel respectively at temperature range of 1000-1250°C in 50°C increments and after their subsequent thermal annealing at temperature range of 400-950°C together with control samples of silicon doped with sulfur and nickel, it was revealed that impurity centers of sulfur and nickel do not interact with each other in the matrix of silicon. The absence of such interaction is possibly due to the fact that the electronic configuration of the impurity centers of nickel in the crystal lattice of silicon turns out to be in the filled 3d10 state, which gives it the character of an inert gas. In view of the absence of interaction of sulfur and nickel in silicon, it is concluded that electrically neutral chemically bound complexes in silicon are formed between sulfur substitution centers and centers of transition metal atoms.

Sulfur and iron influence the transformation and accumulation of mercury and methylmercury in the soil-rice system

Much attention is directed to the accumulation of mercury and methylmercury (MeHg) in rice grown on Hg-contaminated paddy fields, since they pose a risk to the health of both people and wildlife. Ultimately, measures to control the accumulation of Hg and MeHg in rice should become a key focus of research on this topic. The objective of this study is to test whether Hg and MeHg accumulation are reduced in polished rice when iron and sulfur are added together to the paddy fields during the cultivation of rice. In this experimental study, rice plants were grown in pots amended with sulfur and iron. Rice paddy soil contaminated by mercury chloride in the sewage water used for irrigation was simulated in this experiment by Hg-contaminated soil. The total mercury (THg) content added to the soil as mercury chloride reached 120 mg kg−1 as the weight of the dry soil. Two levels of iron (0 and 200 mg kg−1 as FeCl2) as well as sodium sulfate and cysteine (Cys) were added via watering. Two 30-day rice seedlings were transplanted into a root-bag (20 cm long, 12 cm wide), filled with fine quartz sand and cultured in a plastic barrel filled with 4.5 kg of waterlogged soil. When the rice plants matured, samples were taken. The addition of iron and sulfur to the Hg-contaminated paddy soil increased the dry weight of rice grains. The THg and MeHg mainly concentrated in the upper soil layer, and the concentrations of MeHg in the treatments with iron and sulfur were especially higher than that of the control. The addition of iron, sulfate and iron, and cysteine and iron decreased THg concentrations in polished rice by 17.7, 38.3, and 21.3%, respectively. The addition of iron, sulfate and iron, or cysteine and iron decreased the MeHg concentration up to 29.9, 36.4, and 48.2% in polished rice, respectively. Thus, we infer that the coupling of sulfur and iron (II) plays an important role in decreasing the accumulation of MeHg in polished rice. The addition of iron and sulfur together decreased the concentration of THg and MeHg in polished rice. These results can help control concentration levels of MeHg in rice; however, further study of the mechanism of the interaction of sulfur and iron in Hg-contaminated paddy soil should be conducted.

Preparation of sulfur pigments based on the interaction of sulfur with aniline

The article presents the results of obtaining and investigating the various ratios of the components of aniline hydrochloride-S-CaO (Al2O3) 1: 0.4: 0.6; 1: 1: 0.6; 1: 2: 10; 1:10:10 – up to ten times the binding of sulfur and oxides to aniline, having a different color range from dark green to light brown, depending on the composition of the components. In sulfurous composites with various molar ratios of sulfur components, which plays the role of an inorganic filler, it binds almost completely, while remaining chemically inert.

Interaction of TiS2 and Sulfur in Li-S Battery System

With the ability to adsorb polysulfide, electronically conductive and electrochemically active TiS2 is an effective multifunctional cathode additive to improve Li-S battery cycling performance. By using X-ray Photoelectron Spectroscopy (XPS), direct evidence is obtained to demonstrate the strong interaction between Li-polysulfide and TiS2. The observation of Li signature on Li2S8 treated TiS2 proves that the TiS2 possesses the ability to adsorb Li-polysulfides species on its surface. An electron density transfer from Ti to Li and S is identified based on the positions of the peaks in the XPS spectrum before and after the interaction, which is consistent with the theoretically predicted polysulfide-TiS2 interaction models in the literature. TiS2 sample with 2.5x higher BET surface area is obtained by milling the raw TiS2 particles and used as cathode additive in the sulfur electrode. In the presence of TiS2 additive, long cycle life and improved sulfur utilization of Li-S cells under high rate discharge are demonstrated. In addition, we find that a uniform TiS2 distribution in the sulfur-TiS2 hybrid electrode is vital in determining its effectiveness in enhancing the performance of sulfur electrodes. Therefore, processing method and condition should be very important considerations in future development of sulfur electrodes with TiS2 additive.

Interaction of FeS2 and Sulfur in Li-S Battery System

Many transition metal sulfides are electronically conductive, electrochemically active and reversible in reactions with lithium. However, the application of transition metal sulfides as sulfur cathode additives in lithium-sulfur (Li-S) batteries has not been fully explored. In this study, Pyrite (FeS2) is studied as a capacity contributing conductive additive in sulfur cathode for Li-S batteries. Electrochemically discharging the S-FeS2 composite electrodes to 1.0 V activates the FeS2 component, contributing to the improved Li-S cell discharge energy density. However, direct activation of the FeS2 component in a fresh S-FeS2 cell results in a significant shuttling effect in the subsequent charging process, preventing further cell cycling. The slight FeS2 solubility in electrolyte and its activation alone in S-FeS2 cells are not the root causes of the severe shuttling effect. The observed severe shuttling effect is strongly correlated to the 1st charging of the activated S-FeS2 electrode that promotes iron dissolution in electrolyte and the deposition of electronically conductive FeS on the anode SEI. Pre-cycling of the S-FeS2 cell prior to the FeS2 activation or the use of LiNO3 electrolyte additive help to prevent the severe shuttling effect and allow the cell to cycle between 2.6 V to 1.0 V with an extra capacity contribution from the FeS2 components. However, a more effective method of anode pre-passivation is still needed to fully protect the lithium surface from FeS deposition and allow the S-FeS2 electrode to maintain high energy density over extended cycles. A mechanism explaining the observed phenomena based on the experimental data is proposed and discussed.

Catalytic supercritical water gasification: Interaction of sulfur with ZnO and the ruthenium catalyst

Continuous catalytic supercritical water gasification (CSCWG; 400°C, 28MPa) of microalgal biomass (Chlorella vulgaris) was carried out at the microalgae production site of ZHAW in Wädenswil (Switzerland) non-stop over a period of 100h. Characterization of the spent catalyst showed that mainly sulfur poisoning, and to a lesser extent coking, salt deposits, and some sintering of the Ru nanoparticles were responsible for the deactivation of the catalyst after 55h of time on-stream. The commercial zinc oxide adsorbent exhibited a high mechanical stability and good sulfur adsorption performance under supercritical water conditions although its specific surface area collapsed. In summary, the use of a zinc oxide adsorbent upstream of the catalyst bed, together with a higher ruthenium loading of the catalyst, improved the long-term performance of the CSCWG process significantly.

Manifestation of intermolecular interactions in FTIR spectra of methylene blue molecules

Fourier-transform infrared (FTIR) spectra of cationic dye methylene blue (MB) were analyzed in its free form (gas-phase), hydrated crystalline state, and dried MB solution. A good agreement of experimental FTIR spectra with the results of theoretical calculations of MB vibration modes was observed. The calculations were performed by means of the density functional theory (DFT/B3LYP/6–31+G(d)), using Gaussian-03 software package. Vibrational bands of the N+(CH3)2 (1640–1650cm−1) and C-S-C (625-615, 1095cm−1) functional groups are characteristic of the presence of MB monomers in the studied samples. The participation of the N+(CH3)2 functional group in the formation of one bridging H-bond with OH groups of the solvent has been confirmed. The decrease in intensity of these bands with the increase of the fraction of dimers and H-aggregates of MB was observed. It was concluded that the configuration and primary localization of the charge in the heterocycle of ionic form MB+ are changed in the case of formation of dimers and H-aggregates. For samples with a dominant fraction of dimers and H-aggregates, the occurrence of intermolecular H-bonds of the type Nhet…Н-O⋯S+het was found. The occurrence of peaks at 1339–1356, 1481–1491, and 885cm−1 was observed. It was concluded that there is formation of dimers and H-aggregates due to interaction of sulfur and nitrogen atoms with OH groups of water molecules. Moreover, the manifestation of π-π stacking interactions of aromatic rings of the heterocycle of ionic form MB+ during self-association was determined on the basis of data on the behavior of the peaks of heterocyclic of СН (3050–3015cm−1), СС, СN (1600–1595cm−1), СС, and СN (1564–1546cm−1) vibrations.