Amount Of Sulfur Research Articles

Mechanical and Durability Properties of Rubberized Sulfur Concrete Using Waste Tire Crumb Rubber

The use of rubber crumbs provides a viable solution for alleviating the disposal problem of waste tires. In this study, rubberized sulfur concrete (RSC) was researched to investigate the optimal mixture proportion and to improve the mixing process in terms of compressive strength and durability performance. For the mixture of the RSC, sand, rubber particles, and micro-filler were adopted as aggregates and sulfur was used for the binding material. Moreover, two mixing processes were applied: the dry mixing process and the wet mixing process. Based on the test results, the increment of rubber particles in the mixture led to a decrease in the compressive strength for both the dry and wet mixing processes. To minimize the voids between the sand and rubber particles, the micro-filler was used at 5% of the total volume. The amount of sulfur varied slightly depending on the mixing process: 30% sulfur for the dry mixing process and 34% sulfur for the wet mixing process, respectively. Consequently, compared to the dry mixing process, the wet mixing process increased the bonding force between sulfur and rubber powder due to the simultaneous heating and combining. In toughness, the wet mixing process demonstrates a 40% higher energy absorption capability compared to the dry mixing process. For the durability performance of the RSC, the mixture with 20% rubber particles produced using the wet mixing process exhibited better corrosion and freeze–thaw resistance.

Characterization of Sulfur Oxidizing Bacteria and Their Effect on Growth Promotion of Brassica napus L.

Oil seeds sector is one of the major dynamic components of the agriculture world. Oil seeds such as canola (Brassica napus) require a higher quantity of sulfur (S), which is supplied through inorganic fertilizers. However, the overapplication of agro-chemicals to get higher yields of crops is harming the soil health. Therefore, the application of bacterial cultures with plant growth-promoting activity as biofertilizers ensures soil health maintenance and enhances crop productivity. To achieve this aim, the present research was initiated by procuring three sulfur-oxidizing bacteria (SOBs), namely, SOB 5, SOB 10, and SOB 38, from the Microbiology Department, PAU. In the initial assessment, all three SOB cultures showed resilience to pesticide toxicity at the recommended dosage, with the exception of ridomil. These cultures were later characterized morphologically, biochemically, and at the molecular level using 16s rRNA resulting in their identification as Enterobacter ludwigii strain Remi_9 (SOB 5), Enterobacter hormaechei strain AUH-ENM30 (SOB 10), and Bacillus sp. 5BM21Y12 (SOB 38). Functional characterization of these SOB cultures revealed their ability to exhibit multifarious plant growth-promoting traits. Bacillus sp. 5BM21Y12 showed greater functional activity, including high P solubilization (14.903 µg/mL), IAA production (44.28 µg/mL), siderophore production (13.89 µg/mL), sulfate ion production (0.127 mM), ammonia excretion (2.369 µg/mL), and Zn solubilization (22.62 mm). Based on the results of functional and molecular characterization, Bacillus sp. 5BM21Y12 was selected for field trials by formulating different treatments. Composite treatment, T8 (100% S + Bacillus sp. + pesticides) significantly enhanced growth parameters (plant height, root, and shoot biomass), yield attributes (siliqua length, test weight, number of siliqua/plant), yield parameter (total biomass and seed yield), quality parameter (crude protein and oil) as compared to all other sole treatments employed in the field. A combined application of non-pathogenic Bacillus sp. 5BM21Y12, with good functional activity enhanced yield of crop due to synergistic and additive interaction with fertilizer/pesticides. As biofertilizer application reduces the input of pesticides/fertilizers new inoculant formulations with cell protectors and the development of compatible pesticides should be searched to assure the benefits of integrated treatment.

High-Energy-Density Lithium–Sulfur Battery Based on a Lithium Polysulfide Catholyte and Carbon Nanofiber Cathode

Li–S batteries are promising large-scale energy storage systems but currently suffer from performance issues; a major reason is the dissolution of polysulfides in electrolytes. To this end, we report a high-energy-density Lithium–Sulfur (Li–S) battery that combines a catholyte and a sulfur-free carbon nanofiber (CNF) cathode. The cathode was synthesized by carbonizing binder-free polyacrylonitrile (PAN) nanofibers, affording a high surface area. In the catholyte, added polysulfides acted as both conductive Li salts and active materials. Investigating the electrochemical performance of this concept in both Swagelok- and pouch-type cells afforded energy densities exceeding 3 mAh cm−2 at a discharge rate of 0.1 C. This combination could also be utilized in high-capacity pouch cells with capacities of up to 250 mAh g−1. Both cell types exhibited good cycle performance. Adding LiNO3 to the electrolyte suppressed the redox shuttle reactions. Moreover, the cathode being binder-free increased the energy density and simplified cathode fabrication. Characterizing the cathode before and after cycling revealed that deposition was reversible, and that cell reactions at least partially formed sulfur as the end product, resulting in high sulfur amounts in the cell. We expect our concept to greatly aid in the development of practically applicable Li–S cells.

Modulation of shape memory properties of trans-polyisoprene by sulfur

Abstract In this paper, TPI/S composites were prepared by a simple physical melt blending method, and the composites were hot-pressed and molded using a vulcanization system. The effect of cross-linking on the vulcanization properties, mechanical properties, crystalline properties, and shape memory properties of trans-1-4 polyisoprene (TPI) was investigated by varying the amount of sulfur (S). It was shown that with the increase of sulfur dosage, both TPI scorch time and orthoclave time were shortened and the mechanical properties decreased; The melting peak area and melting temperature of the crystalline region of TPI decreased with the increase of sulfur content, and the cross-linking density increased while the crystallinity tended to decrease and the heat resistance deteriorated; In addition, with the increase of sulfur content, the shape return rate of TPI/S composites was increasing and the shape fixation rate was decreasing. When the TPI/S composites were used as shape memory materials, the sulfur dosage of 1 phr had the best shape memory performance, at which time the shape fixation rate of the composites reached 96.9% and the shape recovery rate reached 86.2%. When the sulfur content was elevated to 2 phr, the shape memory fixation rate was significantly decreased, indicating that the shape memory properties were severely compromised. This study reveals that the quantity of sulfur exerts a significant influence on the application of TPI/S composites. An appropriate amount of sulfur can facilitate the preparation of thermoplastic elastomers for utilization in shape memory materials. Nevertheless, an excessive amount of sulfur will substantially enhance the internal cross-linked structure of the composite and deteriorate the shape memory performance.


Collapse of G+/G- bands, modification of Breit–Wigner–Fano signals and structural amorphization in single wall carbon nanotube networks under great excess of sulfur

The identification of superconductivity and ferromagnetic to superconductive transitions in sulfur-modified carbons has recently attracted an important attention. Additional work is however needed to better understand the structural modification of the graphitic interfaces in presence of sulfur. Here we report on an advanced methodology which involves soaking of large amounts (in the order of 500 mg) of sulfur through several annealing cycles into bundles comprising of hollow single-wall/few-wall carbon nanotubes (SWCNTs). TEM, HRTEM, XRD and Raman spectroscopy characterization analyses reveal the presence of structural amorphization of the SWCNTs, with dramatic impact on the intensity of the G+ and a progressive vanishing of the G- signal-contribution. We demonstrate the presence of high sulfur content by employing both point and mapping energy dispersive X-rays (EDX maps) acquisitions, with high local quantities of sulfur in the order of 16 %. Interestingly, a complex variation in the contribution of the Breit-Wigner-Fano (BWF) band, with appearance of extra D, G+ and C-S band-contributions, is revealed by deconvolution-analyses. The appearance of these structural features is a clear indicator of structural amorphization of the CNTs, with consequential formation of C-S hybrid structures, which we analyze systematically with the aid of energy dispersive X-ray spectrum mapping and Raman point/mapping spectroscopy approaches.

Upgrading of kraft lignin pyrolysis products: Managing sulfur impurities

Pyrolysis stands as a powerful method for the valorization of biomass like kraft lignin, an aromatic-rich and sulfur-containing polymeric by-product from the pulping industry. Sulfur in the raw matrix is released during thermal processes and is redistributed in pyrolysis products. However, the presence of sulfur lowers the quality of products due to its corrosive and toxic character. In this work, commercial activated carbons have been used as adsorbents to remove the main sulfur compounds from the gas phase (i.e., CH3SH, COS, H2S). The analysis of sulfur content in biochar has been performed through SEM-EDXS, while the sulfur content in oils has been obtained by GC–MS analysis. The adsorption of sulfur on the activated carbon bed results in an enhancement of the release of sulfur in the gas phase from 34 % without activated carbon to 44 %. Up to 88 % of H2S removal is achieved after the adsorption step, together with a reduction of the overall sulfur content in the bio-oil rich in intermediates such as guaiacols and alkylated phenols. The residual sulfur contained in the liquid product is lowered to 3 % of the total sulfur in the system, thus improving the quality of the liquid pyrolysis product. This process limits the amount of sulfur in the gas and improves its quality and market value. At the same time, this results in a redistribution of sulfur in pyrolysis products such as bio-oil, improving its range of application as a source of chemical intermediates from kraft lignin.

Experimental determination of the sulfur K-shell fundamental parameters employing the holistic approach

Abstract Sulfur and its compounds are both very abundant in the environment and very important for technological applications such as batteries. X-ray spectroscopic characterizations of sulfur compounds for a quantitative determination of the present amount of sulfur often requires a good knowledge on the atomic fundamental parameters involved. These quantitatively describe the processes of photoionization and X-ray fluorescence emission, making them crucial for X-ray spectroscopy-based quantifications. 
By employing the recently demonstrated holistic approach, the atomic fundamental parameters of the sulfur K-shell were experimentally determined using the radiometrically calibrated instrumentation of the Physikalisch-Technische Bundesanstalt (PTB). The transition probabilities of the main K-shell fluorescence lines, the K-shell fluorescence yield, the K-shell Auger yield, the subshell photoionization cross section and fluorescence production cross section were determined by means of photon energy dependent X-ray fluorescence and transmission measurements on a thin InS coated silicon nitride membrane. The results are also downloadable from Zenodo as plain text.

Investigations on optical properties of synthesized covellite CuS hollow nano cubic structures

In this work, hollow nanocubes of CuS were synthesized by employing a chemical route via Kirkendall effect. The influence of sulphur concentration on the optical and structural properties of CuS by varying the amount of sulphur during synthesis was investigated. The synthesized hollow cubes were characterized by using Scanning Electron microscope (SEM), X-Ray Diffraction (XRD) Analysis, Ultra Violet -Visible (UV-Vis.) Spectroscopy, Photoluminescence (PL) Spectroscopy, Raman Spectroscopy and X-ray photoelectron Spectroscopy (XPS). The formation of cubic morphology was affirmed by SEM analysis in all three samples. The length of the sidesthe of the cube lies in the range of 500-600 nm. XRD studies confirmed the formation of the pure phase of covellite CuS. Also, XPS analysis validated the presence of excess sulphur in the sample with Cu:S as 1:150 along with variation in the stoichiometric ratio of 1: 0.5. Since, this was not the case for Cu:S as 1:100, as it showed the desired stoichiometry of 1.1: 0.9 that supports the pure phase of CuS. Raman spectra further confirmed the purity of the sample. Absorption analysis revealed a well-defined bandgap with the absence of an intermediate defect state with a bandgap of 1.4 eV in the optimized sample. PL spectra displayed a decent recombination rate and minimum non-radiative losses in the 1:100 sample. These outcomes assurances the sample with Cu:S as 1:100 could be used as a potential material for solar cell applications.

Investigating the Synergistic Effects of Using Nitrogen and Sulfur Fertilizers on the Growth of Safflower (<i>Carthamus tinctorius</i> L.)

Nutrient imbalance is one of the prevalent problems in the semi-arid region. The study aimed to investigate the effects of sole and simultaneous application of nitrogen and sulfur on safflower yield in a semi-arid region. A field trial was designed to explore the combined use of sulfur (S0: control, S1 and S2: 25 and 50 kg ha-1 S via sulfur phosphate composites, S3 and S4=: 25 and 50 kg ha-1 of S via elemental sulfur, S5 and S6: 25 and 50 kg ha-1 of S via zinc sulfate) and nitrogen (0, 40 and 80 kg ha-1) on the growth and seed production of safflower (Carthamus tinctorius L.) in a west of Iran with mesic active calcixerepts soil that had medium to low fertility. The utilization of large amounts of nitrogen greatly increased the height of the first pod from the ground surface (P ≤ 0.05), and the highest amount was recorded in S 6+ N80 conditions (65%). Leaf chlorophyll content was significantly affected by nitrogen consumption (P ≤ 0.01) and the highest chlorophyll was recorded in S4, S5, and S6 treatments having high levels of nitrogen. A similar trend was observed for the canopy width and the application of nitrogen, zinc sulfate, and elemental sulfur could increase this component by 33%. The highest number of heads was achieved with the use of S5 + N80 and S2 + N80, which was 15% more compared to the control. The application S2 + N80 increased seed number in capitulum by 25% over the control. The application of S along with high levels of nitrogen improved the seed yield by 45% (1334 ± 78.35 kg ha-1). However, only the application of sulfur could improve the harvest index (P ≤ 0.05). The results indicated that applying moderate to high amounts of zinc sulfate and elemental sulfur, in combination with N80, enhanced safflower growth characteristics and improved seed yield components, likely due to synergistic interactions between the elements. Altogether the use of zinc sulfate or elemental sulfur as a logical and effective management solution can increase the efficiency of nitrogen fertilizer and improve nutritional balance.

Oxidative weathering of pyrite in acidic environments: Data-driven experimental evaluation coupled with Raman hyperspectral imaging

This study deals with the identification of the factors that affect pyrite oxidation in acid mine drainage conditions. For this scope, weathering experiments have been carried at laboratory scale based on the design of experiments methodology to evaluate the effect of factors such as major ion concentrations, crystal size, and humic acids presence over the amount of elemental sulfur produced due to the involved weathering reactions. In particular, metal and anionic concentrations in solution were quantified by inductively coupled plasma-atomic emission spectroscopy and ion-chromatography techniques, respectively, whereas the amount of elemental sulfur was quantified with a high-performance liquid chromatography with diode-array detection technique after proper extraction procedure. A partial least squares regression was calculated to establish a quantitative relationship between the considered factors and the amount of elemental sulfur. After evaluation of the model, ferric iron, crystal size and the presence of humic acids were identified as the relevant factors for pyrite oxidation under acidic conditions. In addition, the surface of the samples was characterized by Raman imaging spectroscopy and subsequently analyzed by explorative hyperspectral analysis methods to assess the spatial distribution of the elemental sulfur as the main weathering product, resulting in a homogenous distribution.

Preparation and characterization of MgO-based composites: Analysis of moisture, corrosion, and fungal resistance, and mechanical properties

Magnesium oxide (MgO) composite boards are valued in the construction industry because of their outstanding fire resistance, however, the long-term viability of MgO boards is affected by atmospheric humidity. This research work aims to investigate the environmental impacts and mechanical properties of four types of MgO boards from four different manufacturers under varying relative humidity (RH) levels. Three of them contained a high amount of chlorine known as magnesium oxychloride (MOC) boards, and one of them contained a high amount of sulfur known as magnesium oxysulfate (MOS) boards from their elemental composition observed by EDX. Microscopic images showed a rougher and porous surface for MOC boards, whereas smoother surface for MOS boards. MOS boards exhibited 37 % (average) lower moisture absorbency than MOC boards at 95 % RH and remained dry, while the MOC boards leaked salty water drops under the same condition. As a result, the MOS boards exhibited much better corrosion and fungal protection than the MOC boards. Mechanical properties, for example, tensile strength decreased by 45 % in MOC boards and 31 % in MOS boards at 95 % RH compared to 50 % RH. Therefore, the sourced MOS composite boards outperformed the contemporary MOC boards in all parameters.

Modification of clinoptilolite as a natural zeolite by copper oxide nanoparticles for efficient desulfurization of kerosene

In recent years, researchers are looking for ways to reduce the amount of sulfur in kerosene. Therefore, desulfurization of kerosene is considered an important commercial and environmental process. Among the hard and complicated methods available for the desulfurization process, natural zeolites can be a suitable alternative for the desulfurization of oil products due to their economic efficiency, biocompatibility, and natural abundance of oil reserves. In this research, natural zeolite (clinoptilolite) was modified with CuO nanoparticles and used as adsorbent for desulfurization of kerosene. The effect of important parameters such as adsorbent dose, pH of solution and initial adsorbate concentration were investigated. Results indicated the optimum conditions as follows: dose of adsorbent 2 g, pH 10 and the adsorbate dose 200 ppm. Results showed that the modified adsorbent is a suitable, low-cost and good efficiency for the desulfurization process of kerosene.

Appropriate sulfur fertilization in contaminated soil enhanced the cadmium uptake by hyperaccumulator Sedum alfredii Hance

The biogeochemical processes of sulfur and heavy metals in the environment are closely related to each other. We investigated the influence of sulfur addition on hyperaccumulator Sedum alfredii Hance growth, cadmium (Cd) accumulation, soil Cd bioavailability, soil bacterial communities and plant transcriptome responses. The results showed that an appropriate rate of sulfur addition (1.0 or 2.5 g/kg) enhanced the growth of Sedum alfredii Hance plants as well as their accumulation of Cd. A high rate of sulfur addition (5.0 or 10.0 g/kg) causes toxicity to Sedum alfredii Hance plants. The application of an appropriate amount of sulfur to the soil increased the abundance of sulfur-oxidizing bacteria such as Sulfuriferula and Thiobacillus; acid-fast bacillus such as Alicyclobacillus; and cadmium-tolerant bacteria such as Bacillus and Rhodanobacter. This led to a decrease in pH and an increase in bioavailable Cd in the soil. RNA sequencing revealed that the addition of sulfur to soils led to the up regulation of most of the differentially expressed genes (DEGs) involved in “photosynthesis” and “photosynthesis, light reaction” in Sedum alfredii Hance leaves. Moreover, the “plant hormone signal transduction” pathway was significantly enriched with sulfur addition. Sulfur assimilation in Sedum alfredii Hance plants may promote photosynthesis and hormone synthesis, leading to Cd tolerance in these plants. Our study revealed that sulfur fertilization enhanced the efficiency of Cd phytoremediation in Sedum alfredii Hance plants.

Sulfur Modified Copper Nitride for Electrochemical CO2 Reduction Reaction

Metallic copper has been attracted attention as efficient catalyst for electrochemical CO2 reduction reaction (CO2RR). However, the activity of the catalyst with a single adsorption site is limited by the imbalance of the intermediate binding energy, so-called “scaling relationship”. [1] Therefore, it is crucial to break the scaling relationship between reaction intermediates in order to increase product selectivity and lower overpotential. One of the candidates to overcome this scaling relationship is metal sulfide. According to the computational study, since sulfur atoms work as an adsorption site, metal sulfide is expected to be a suitable catalyst for CO2RR with multiple adsorption sites.[2] In addition, surface modification by sulfur is also effective approach to enhance product selectivity in CO2RR. Increase of formate (HCOO-) selectivity by sulfur introduction on Cu has been reported in some previous reports.[3]-[5] On the other hand, the repulsion between the oxygen lone pair electrons of the CO2 molecule and the electronic clouds of the surface sulfur atoms become an obstacle on CO2RR.[6] A potential solution to this problem is the construction of sulfide-nitride composite. Because of the difference in electronegativity between nitrogen and metal or sulfur, it is considered that the electronic structure of the metal sulfide is altered to reduce the repulsion between oxygen and sulfur.[7] Based on these backgrounds, it is expected that the CO2RR activity of copper nitride (Cu3N) will be enhanced by sulfur introduction.Here, sulfur modified Cu3N with different amount of sulfur were synthesized by reflux method with some modification of previously reported method.[8] X-ray diffraction pattern and SEM-EDX elemental analysis result indicate that the sulfur ratio increases and copper sulfide (Cu2S) crystal phase appears with the amount of sulfur source precursor. CO2RR activity was evaluated in 0.1M KHCO3 electrolyte, and volcano trend was identified between the amount of sulfur and methane selectivity. Among all the catalysts including pure Cu3N and Cu2S which were synthesized by the same method, 4.2 mol% sulfur containing Cu3N showed the highest methane faradaic efficiency (41.4 %). This faradaic efficiency is more than 10 times higher than that of Cu3N (0.48 %) and Cu2S (1.3 %). This finding offers valuable insights into the sulfur role on the modified catalyst.

Mesoporous Carbons Produced from Tannin Biomass for Lithium-Sulfur Batteries

Lithium-sulfur batteries (LSBs) are promising alternatives since sulfur can provide a theoretical specific capacity of 1675 mA h g-1 when combined with lithium [1]. Thus, LSBs can achieve a theoretical energy density (2500 W h kg-1) that is much greater than that of conventional lithium-ion batteries [1]. However, several problems must be resolved to enable commercial production on a large scale, such as the formation of soluble species of lithium polysulfides [2]. Various approaches have been used to minimize this problem, including the development of carbon-based hosts capable of retaining these polysulfides. Among these, the development of cathodes based on carbon‒sulfur composites using carbon from biomass is an alternative that benefits from the possibility of obtaining materials with a modifiable surface area and porosity at low cost [2]. On this basis, this work reports the synthesis of mesoporous carbons (MCs) from tannin biomass, the incorporation of sulfur and the development of lithium-sulfur batteries. The MC sample was produced using the solvent-free method [3] and was named C. The incorporation of sulfur into mesoporous carbons was carried out using melt diffusion methodology [4]. Two quantities of sulfur were added to the carbon host by mass, and the materials were named CS1 and CS2 at ratios of 1:1 and 2:1, respectively, in relation to sulfur:MC. Coin cells (CR 2032) were assembled using the produced materials on the cathode, metallic Li on the anode and the electrolyte 1 M LiTFSI and 1% (w/v) LiNO3 in 1,2-dimethoxyethane/1,3-dioxolane (DME/DOL) and characterized by cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) cycling. The mesoporous carbon C presented a type IV isotherm characteristic of mesoporous materials, with a BET surface area of 539 m2g-1, average pore size of 7.7 nm and total pore volume of 0.747 cm3g-1. There was a decrease in the area and pore volume of the materials after sulfur incorporation, reaching 70 m2g-1 and 0.195 cm3g-1 for CS1 and 3 m2g-1 and 0.012 cm3g-1 for CS2, respectively. The sulfur contents were determined by thermogravimetric analysis (TGA) and were 39% and 61% for CS1 and CS2, respectively. The sulfur contents determined by TGA were close to those obtained by elemental analysis (CHNS), which were 45% and 63% for CS1 and CS2, respectively. The CV data showed that both cells presented cathodic and anodic potentials typical of Li-S batteries. The GCD data show that the cell containing the cathode with the material with a higher elemental sulfur content (CS 2) is stable and maintains specific capacities on the order of 550 mA h g-1 after 45 galvanostatic cycles at different current densities. However, this cell showed a more abrupt decrease in capacity at the highest rates (2C and 4C), Figure 1. Most likely, the higher sulfur content used in this sample did not result in total impregnation of the porous structure, resulting in sulfur deposition on the surface of the particles. As a result, the interparticle contact resistance in the electrodes increases, which limits the performance at higher current demands. For the cell built with the sample containing 39% S (CS1), excellent performance is obtained at high C rates. At 0.1 C, the cathode operates above 900 mA h g-1 in the initial cycles and above 550 mA h g-1 at 0.5 C, and no significant capacity drop is observed between 1 C and 2 C (≈500 mA h g-1). At 4C, a decrease in the specific capacity is noted, but the specific capacity remains above 350 mA h g-1. These results demonstrate the potential of carbon materials obtained from biomass for building high-performance Li-S batteries.Acknowledgments: The authors thank the financial support from the Rota 2030 Program at Fundep – Brazil.

Nature-Derived Sulfur Carbons for Highly-Efficient Room Temperature Sodium-Sulfur Energy Storage

In recent years, a growing interest in “beyond-Li-ion“ batteries has caused a speedy development of alternative battery technologies based on other alkali metals. Room temperature sodium sulfur (RT Na-S) batteries are potential candidate for sustainable large-scale energy storage systems. They offer low cost, nontoxicity and natural abundance of both cathode and anode materials combined with high theoretical energy density. However, rapid capacity fading related to the irreversible shuttling of soluble polysulfides, poor reaction kinetics and low sulfur utilisation in the cathode materials significantly limit their practical application.In this work, a microporous sulfur-carbon complex is produced from sustainable natural precursors in a one-pot synthesis via stepwise thermally-induced inverse vulcanisation and condensation. The material exhibits a unique structure, with sulfur chains covalently anchored to the conductive carbon matrix and physically confined in ultra-micropores. An increase in sulfur content in the sulfur-copolymer alters the morphology and chemical composition of the final sulfur-carbon material, enhancing the amount of long-chain sulfur. The combination of optimal microstructure, good electrical conductivity and high content of electrochemically active sulfur translates to an unprecedented ~99% utilisation of sulfur and the highest reported capacity for a room temperature Na-S cathode, along with high rate capability, coulombic efficiency and long-term stability. This study offers an innovative approach towards the understanding of the key chemico-physical properties of the sulfur-carbon composite materials for the development of high-performance cathodes in RT Na-S batteries with an atom-efficient utilisation of sulfur.

Theoretical background and results of a study on changes in oil alkalinity of diesel engines

Abstract Alkalinity is a primary indicator for neutralizing insoluble impurities in oil. Alkaline additives decrease as oils interact with fuel combustion products containing significant amounts of sulfur and nitrogen. Literature data suggests that adding 2-3% of an effective ashless dispersant of a specified type can be equivalent to increasing the alkaline number of the oil by approximately 10 mg KOH/g through the addition of a metal-alkalinity additive to the oil. Based on operational study results, it can be concluded that after the first 100 hours of operation, the alkalinity value ranges from 6-4.3 mg KOH/g, and after 300 hours of operation, the alkalinity value reaches its maximum value of 2 mg KOH/g. Oils with an alkalinity of less than 2 mg KOH/g already indicate an unsatisfactory condition of the oil when lubricating the engine. To maintain the alkalinity value at a given level, it is recommended to continuously introduce tribomechanical stabilizers into the engine lubrication system.

Structural and biochemical characterization of an encapsulin-associated rhodanese from Acinetobacter baumannii.

Rhodanese-like domains (RLDs) represent a widespread protein family canonically involved in sulfur transfer reactions between diverse donor and acceptor molecules. RLDs mediate these transsulfuration reactions via a transient persulfide intermediate, created by modifying a conserved cysteine residue in their active sites. RLDs are involved in various aspects of sulfur metabolism, including sulfide oxidation in mitochondria, iron-sulfur cluster biogenesis, and thio-cofactor biosynthesis. However, due to the inherent complexity of sulfur metabolism caused by the intrinsically high nucleophilicity and redox sensitivity of thiol-containing compounds, the physiological functions of many RLDs remain to be explored. Here, we focus on a single domain Acinetobacter baumannii RLD (Ab-RLD) associated with a desulfurase encapsulin which is able to store substantial amounts of sulfur inside its protein shell. We determine the 1.6 Å x-ray crystal structure of Ab-RLD, highlighting a homodimeric structure with a number of unusual features. We show through kinetic analysis that Ab-RLD exhibits thiosulfate sulfurtransferase activity with both cyanide and glutathione acceptors. Using native mass spectrometry and in vitro assays, we provide evidence that Ab-RLD can stably carry a persulfide and thiosulfate modification and may employ a ternary catalytic mechanism. Our results will inform future studies aimed at investigating the functional link between Ab-RLD and the desulfurase encapsulin.

Thermodynamic Properties of Sulfur in the CaO–AlO1.5–CeO1.5 Slag System at 1873 K

Elements with a high affinity for O and S in molten steel are desirable as deoxidizing and desulfurizing agents in the steel refining process, and Ce has attracted attention. In this study, the thermodynamic properties of sulfur in a CaO–AlO1.5–CeO1.5 slag system at 1873 K are investigated. A chemical equilibrium method using Cu is employed for these measurements. Sulfide capacities are determined in the CaO–AlO1.5–CeO1.5 system to show desulfurization ability; the precipitated phases are identified when large amounts of sulfur are added to the CaO–AlO1.5–CeO1.5 system; the solubility of CaS in the CaO–AlO1.5–CeO1.5 system is determined. It is suggested that the slag of this system can improve sulfur distribution while reducing the Al concentration in the steel.

A sulfur-infiltrated mesoporous silica/CNT composite-based functional interlayer for enhanced Li–S battery performance

The design and construction of functional interlayers for lithium–sulfur (Li–S) batteries has attracted much attention and was demonstrated to be effective to alleviate the notorious “shuttle effect.” An often neglected issue is that the introduction of interlayer will reduce the overall energy density of the battery. In this work, we report a sulfur-infiltrated mesoporous silica/carbon nanotube (CNT) composite as an interlayer for Li–S batteries. The mesoporous silica with large surface area (842 m2 g−1) and pore volume (0.85 cm3 g−1) can not only ensure abundant exposed sites for polysulfide capture but also accommodate a large amount of sulfur inside the pore structure. CNT was composited with silica to enhance the electronic conductivity of the interlayer, which is beneficial for fast sulfur redox reaction kinetics and improved utilization of sulfur. Compared to the pristine and CNT-modified separator, the mesoporous silica/CNT composite-modified separator enables better cycling stability and rate performance. More importantly, it was demonstrated that separately incorporating sulfur into a cathode and interlayer enables better battery performance than locating all the sulfur in the cathode. At a total sulfur loading of 4 mg cm−2 (3 mg cm−2 sulfur on the cathode and 1 mg cm−2 on the mesoporous silica/CNT interlayer), a high initial discharge capacity of 1410 mAh g−1 and a retained capacity of 952 mAh g−1 after 100 cycles were exhibited. This work provides important guidance for future design of functional interlayers for practical Li–S batteries.