Sulfur Ratio Research Articles

Real-time measurements of PM2.5 water-soluble inorganic ions at a high-altitude mountain site in the western North Pacific: Impact of upslope wind and long-range transported biomass-burning smoke

Real-time measurement of PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 μm) water-soluble inorganic ions (WSIIs) was conducted at Lulin Atmospheric Background Station (LABS; 2862 m above mean sea level) in the western North Pacific (WNP) during the autumn 2015 and spring 2016. During autumn, the mountain-valley (M-V) circulation is effective in increasing the mass concentrations of PM2.5, WSIIs, and carbon monoxide (CO) at LABS from 12:00 to 18:00 local time every day. In sharp contrast to autumn, five high aerosol-loading events were recorded during the spring, with each event persisting for a few days. These events were harmonized with the long-range transport of biomass-burning (BB) smoke emissions from northern peninsular Southeast Asia (PSEA), as disclosed from the fire count map and backward trajectories. The plumes appear to mask their characteristic diurnal features driven by the local M-V circulation. During both seasons, the prominent pathway of SO2 to SO42− conversion was aqueous phase oxidation as revealed from the relationship between sulfur oxidation ratio (SOR) and aerosol liquid-water content. Furthermore, NO3− was found to be produced primarily via homogeneous reactions during the spring season. The optical measurements were also made along with the semi-continuous measurements of WSIIs in this study. The magnitude of aerosol scattering and absorption coefficients exhibited high values when LABS was either under the influence of M-V circulation or long-range BB transport, although the latter event was apparently greater. Large surface cooling (up to −30.8 W m−2) and atmospheric warming (up to +21.3 W m−2) at LABS attributed to absorption enhancement by BB-induced aerosols can potentially influence the regional radiation budget.

Crop sulfur status in relation to soil sulfur determined using anion exchange membranes and Mehlich 3

The aim of this study was to find an indicator of plant sulfur status correlating most significantly with bioavailable sulfur in soil. The indicators of plant sulfur status in shoot biomass were: sulfur concentration, mass nitrogen to sulfur (N/S) ratio, mass phosphorus to sulfur ratio and sulfur nutrition index (SNI). The bioavailable soil sulfur was determined using water extraction (S-water), Mehlich 3 extractant (S-M3) and anion exchange membranes (S-AEMs). Results cover four years (2015–2018) of on-farm trials in the Czech Republic with winter wheat, winter oilseed rape and maize, and pot experiments including spring wheat and maize. Shoot biomass of plants was sampled at the beginning of stem elongation (winter wheat, winter rape and maize in on-farm trials), during rapid growth (maize in pot experiment) and during flowering (wheat plants, winter rape). Only soils containing 0.5%–1.7% of organic carbon were studied (median 1.31%). Compared to shoot N/S ratio, sulfur concentration in shoot biomass of maize correlated stronger with bioavailable soil sulfur. However, bioavailable sulfur in soil correlated strongest and most significantly with shoot N/S ratio of winter wheat and winter rape grown in on-farm trials. Except for winter rape grown on non-calcareous soils and maize grown in pot experiment, the shoot N/S ratio correlated more significantly with S-M3 compared to S-water and S-AEM.

Structure elucidation and in vitro biological evaluation of sulfated exopolysaccharide from LAB Weissella paramesenteroides MN2C2

The introduction of new bio-product for human diseases treatment is still a great challenge in drug delivery field. This study aimed to extract, purify and characterize exopolysaccharide (EPS) from Weissella paramesenteroides MN2C2 which identified by 16S rDNA under accession number of MK530206 in gene bank. The chemical and spectroscopic analysis using UV, FTIR, NMR and HPLC were applied. The results revealed that the product composed of 80% fructose, 9.3% glucose and 5.6% sucrose with acetyl groups. EDX analysis demonstrated that it formed of high ratios of carbon, nitrogen, oxygen, phosphorous and sulfur. The three-dimensional structure showed irregular compacted lumps with smooth surface. The anticancer activity revealed that the partially purified EPS was strong anticancer agent and highly selective against Colon Caco-2, Breast MCF-7 and Liver HepG-2 cancer cell lines compared to the crude ones. Both EPSs showed antiviral activity (99.99%) against Coxsackie virus (CVB3). Their DPPH antioxidant activity acted in a dose dependent manner. From the obtained results it was concluded that our EPS can serve as a promising candidate for drug delivery.

Investigation of the cleanability of asphaltite by flotation

Southeastern Anatolia Region of Turkey/Sirnak asphaltites centers are located in and around large reserves in coal mines. Due to the high ash and sulfur content of asphaltite coal, it is important to use it by cleaning with enrichment methods, in terms of solving environmental problems and increasing energy quality. In this study; the main characteristics (chemical analysis, ICP-OES, XRD, SEM analysis) of the asphaltite samples taken from the Avgamasya quarry operating in the center of Sirnak province were determined after the crushing and grinding processes. Later, the asphaltite coal sample was subjected to the flotation enrichment method, which is widely used in fine particle size coal enrichment methods. In the flotation method, the effects of kerosene, fuel oil, and aerophine3418A reagents in different amounts were investigated. Accordingly, the best ash results in the A1(50 g/t kerosene + 0.1 g/t MIBC) experiment; were obtained by adding 50 g/t kerosene reagent and the ash content was determined as 30.80% with an ash content reduction from 46.08% to 33.16%. Best result for reducing the sulfur ratio; in the B2(100 g/t fuel oil + 0.1 g/t MIBC) experiment, it was determined by the addition of 100 g/t fuel oil reagent. Here, the total sulfur content was reduced from 6.46% to 5.71% with a sulfur content reduction of 11.61%.

Stable Isotope Ratios of Herbs and Spices Commonly Used as Herbal Infusions in the Italian Market.

Stable isotope ratio analysis has been widely used for traceability and authenticity purposes in relation to various food commodities, but only in a limited number of herb and spice species. This study explored the stable isotope ratios of carbon, nitrogen, sulfur, oxygen, and hydrogen (δ13C, δ15N, δ34S, δ18O, and δ2H) of 119 herbs and spices belonging to 116 plant species and 57 plant families collected from the Italian market for the first time. The characteristic value ranges of δ13C, δ15N, δ34S, δ18O, and δ2H of the herbs and spices went from −31.0 to −11.6, −4.7 to 12.0, −5.0 to 22.0, 14.7 to 46.0, and −158 to −12‰, respectively. The isotopic profiles within and between common botanical families and their similarity/dissimilarity between herbs and spices belonging to the common botanical families are also discussed here. The results of this exploratory work highlight the possibility of characterizing herbs and spices and suggest widening the scope of the survey through more extensive sampling and focusing on specific plant species.

Highly active Mo doping TiO 2 as sulfur loaded matrix material for lithium‐sulfur batteries with excellent electrochemical performances

Lithium-sulfur batteries have attracted much attention for a long time owing to their high theoretical specific capacity. In this paper, a type of highly active Mo doping TiO2 as sulfur loaded matrix material has been synthesized by a facile solvothermal method. X-ray diffraction and Raman spectrum tests show that Mo atom can enter into the interlayer of TiO2 crystal face and increase the interplanar spacing of titanium dioxide in order to possess a higher electrochemical activity. Small particles morphology and uniform particle size can be evidently observed by scanning electron microscope and after sulfur loading (1:1), it still retains the similar morphology as matrix material. This illustrates that a considerable amount of sulfur has penetrated into the matrix material in order to achieve the ideal sulfur loading effect. When used as electrode active material, it displays the lowest electrochemical and concentration polarization resistance and the specific capacities can reach 1483.08, 1208.57, and 1004.17 mAh g−1 at 0.1, 0.2, and 0.5 C current rates and after 150 cycles, the capacity retention is over 60%. When the sulfur loading mass ratio increases to 1:2 (Mo/TiO2:S), the sulfur composite cathode still maintains considerable lithium-ion diffusion channels and 753.54 mAh g−1 of specific discharge capacity at 0.5 C current rate.

Dense‐Stacking Porous Conjugated Polymer as Reactive‐Type Host for High‐Performance Lithium Sulfur Batteries

AbstractCommercialization of the lithium‐sulfur battery is hampered by bottlenecks like low sulfur loading, high cathode porosity, uncontrollable Li2Sx deposition and sluggish kinetics of Li2S activation. Herein, we developed a densely stacked redox‐active hexaazatrinaphthylene (HATN) polymer with a surface area of 302 m2 g−1 and a very high bulk density of ca. 1.60 g cm−3. Uniquely, HATN polymer has a similar redox potential window to S, which facilitates the binding of Li2Sx and its transformation chemistry within the bulky polymer host, leading to fast Li2S/S kinetics. The compact polymer/S electrode presents a high sulfur loading of ca. 15 mgs cm−2 (200‐μm thickness) with a low cathode porosity of 41 %. It delivers a high areal capacity of ca. 14 mAh cm−2 and good cycling stability (200 cycles) at electrolyte–sulfur (E/S) ratio of 5 μL mgs−1. The assembled pouch cell delivers a cell‐level high energy density of 303 Wh kg−1 and 392 Wh L−1.

First Data on Isotopy and Mineralogical Features Ores Kumirnogo Silver Deposit (Russia, Primorsky Region)

Lockated in the noth part of Primorsky region, the Kumirnoe silver deposit is very interesting object from a geological point of view. Data about isotopic mineralogical characteristics of its ore mineralization was first presented in this essay. More than 80 ore bodies are known at the deposit. They mostly contain quartz, hydromica, sericite, adularia, chlorite, montmorillonite and kaolinite. Ore mineralization is represented by silver-bearing minerals: acanthite, pyrirargyrite, polybasite, stephanite, freibergite, selenium-containing aguilarite and eletrum. The obtained isotope data indicate that sulfur composition is close to meteorite standard, this is indicated by the narrow positive interval of its sulfur ratios (2,0-2,8‰). It gives the reason to assume that homogeneous hydrothermal ore-forming solutions participated in its formation. Its comparison with isotopic data of gold-silver deposits located in the continental marginal volcano-plutonic belts (Ducat, Mnogovershinnoe, Sergeevskoye) shows that the formation of the Kumirnoe deposit was at the same time: Cretaceous- Paleogene, it’s possible it was under similar geological conditions. This is confirmed by the age data obtained by us earlier for Kumirnoe deposit (it matches Cretaceous- Paleogene).

Investigation on Desulfurization of Rejected Electrolytic Manganese Metal Scrap: Experiment and Mathematical Modeling

To improve the recycling efficiency of rejected electrolytic manganese metal (EMM) scrap that contains excessive sulfur, a high-temperature experiment and mathematical model reflecting the mechanism of sulfur transfer from the molten manganese metal to the molten slag were elaborated. A MoSi2 electrical resistance furnace filled with argon protective gas was first employed to perform the desulfurization experiment at 1673 K (1400 °C). Four different fluorine slags with the CaO content ranging from 0 to 20 pct were used in the experiment. A mathematical model of the rejected EMM scrap desulfurization, based on the two-film theory, was established. It adequately described the thermodynamics and kinetics of the rejected EMM scrap desulfurization reaction. In particular, it captured the influence of the interfacial tension between the molten slag and molten manganese for the sulfur transfer process. A comparative analysis of measured and calculated results proved the model feasibility: it took into account the effects of the holding temperature, slag CaO content, the initial sulfur content in rejected EMM scrap, and slag/manganese mass ratio on the desulfurization efficiency. The results indicate that CaO could promote the desulfurization of the manganese metal. The sulfur removal ratio is 58.01 pct with a CaO-free slag at 1673 K (1400 °C), while the ratio increases to 84.58 pct if the CaO content rises to 20 pct. At higher temperatures, the CaO content in the slag can be appropriately reduced. High slag/manganese mass ratios were found to benefit the sulfur removal, while the CaO content in the slag could be adjusted according to the initial sulfur content in the rejected EMM scrap.

Young soils of a temperate barrier island under the impact of formation and resetting by tides and wind

The island Spiekeroog (Germany) at the southern North Sea coast exhibits an island tail (Ostplate) of which large parts formed after 1860 by gradual eastward deposition of marine sediments. This study aimed to (i) provide a first overview of soils on the Ostplate, (ii) verify whether soil formation stages in different landscape elements (dune chain, dune slacks, saltmarsh, pioneer zone) are linked to the island’s gradual development and (iii) to assess the impact of tides and winds on soil formation. Standard physicochemical properties of dune -and dune slack topsoils and 19 pedons (i.a. pH, total organic carbon (TOC), total inorganic carbon (TIC), total nitrogen (TN), and mean weight diameter (MWD) of water stable aggregates) were analyzed. Soils of the dune slacks, the saltmarsh and the pioneer zone classified as Gleysols which showed no trend towards differences along the Ostplate. The dune chain exhibited Protic Arenosols that were initially acidified in lee positions (min. pH = 5.1). Carbon (C) and nitrogen (N) isotopes (δ13C, δ15N) signatures of saltmarsh sediments were used as a proxy for the tidal influence on soil formation. In addition, sulfur (S) isotope (δ34S) signatures revealed insights on sulfur sources in the saltmarsh. The δ13C signatures of organic matter (OM) decreased and TOC/TN -and TOC/total sulfur (TS) ratios increased with increasing elevation and decreasing flooding frequency. At higher flooding frequency, δ15N resembled the dominant input of OM from the southern North Sea, at a lower interaction level, mixing of a wider range of sources was indicated. S isotopes indicated dissolved sulfate and reduced species as sulfur sources. It was concluded that an ongoing impact of wind-induced sand movement at the dunes, and flooding-induced sediment movement in the saltmarsh and the pioneer zone, repealed any potential disparities in soil formation stages, which might have existed along the Ostplate.

Stable isotope evidence of human diet in Mediterranean context during the Last Glacial Maximum

The Final Gravettian in Europe overlapped with the cold and dry climatic event of Heinrich 2 (ca. 27–23.5 kyr cal BP), which caused the contraction of human distribution over refuge regions in the southern peninsulas of Europe. Here, we consider the human subsistence in the northeast Iberian Peninsula, where an extensive range of small to large prey was available. Four human remains from the Serinyà caves were investigated using the stable isotope ratios of carbon, nitrogen, and sulfur of bulk collagen (δ13Ccoll, δ15Ncoll, δ34Scoll) and of phenylalanine and glutamine amino acids (δ15NPhe, δ15NGlu). Direct AMS dating of the human and animal remains from the Final Gravettian levels of Mollet III, Reclau Viver, and Arbreda at Serinyà confirmed their chronological position from 27.5 to 22.6 kyr cal BP and the occurrence of four different human individuals. The δ13Ccoll and δ15Ncoll values showed a large contribution of terrestrial prey to the dietary protein of the individuals. The δ34Scoll values were consistent with a subsistence based on the local continental resources, without detectable contribution of marine resource. The δ15NPhe and δ15NGlu values confirm that freshwater resources were not a substantial component of the diet of the considered individuals. Contrast in the isotopic amounts in bulk collagen could be interpreted as the result of different proportions of terrestrial prey in human diet at Serinyà. Altogether, the isotopic investigation reveals the importance of terrestrial over aquatic resources in the subsistence of the studied Final Gravettian individuals from the Serinyà caves in northeastern Iberia during the Last Glacial Maximum. It would be consistent with a scenario of a productive enough terrestrial ecosystem to sustain hunter-gatherer subsistence in this refuge region.

Realigning the Chemistry and Parameterization of Lithium‐Sulfur Battery Models to Accommodate Emerging Experimental Evidence and Cell Configurations

AbstractExperimental insights into lithium‐sulfur (LiS) battery chemistry have resulted in practical improvements in cell coulombic efficiency, sulfur utilization, and cycle life. However, optimization of this complex battery chemistry requires experimentally aligned modeling tools. A porous electrode theory‐based model incorporating key electrolyte dissociation chemistry is developed for the LiS cell. The proposed chemistry produces a radical anion species that is widely observed spectroscopically in LiS electrolytes. We explore the implications of radical anion formation on the current‐voltage behavior within the context of a state‐of‐art high energy density LiS cell with low electrolyte:sulfur (E/S) ratio and ideally‐protected anode. Parameters describing the dissociation reaction equilibrium and kinetics are shown to alter the electrolyte speciation in ways that can be linked to observations from LiS electrolyte engineering experiments.

Estimating climate change-related impacts on outdoor air pollution infiltration

BackgroundRising temperatures due to climate change are expected to impact human adaptive response, including changes to home cooling and ventilation patterns. These changes may affect air pollution exposures via alteration in residential air exchange rates, affecting indoor infiltration of outdoor particles. We conducted a field study examining associations between particle infiltration and temperature to inform future studies of air pollution health effects. MethodsWe measured indoor fine particulate matter (PM2.5) in Atlanta in 60 homes (810 sampling-days). Indoor-outdoor sulfur ratios were used to estimate particle infiltration, using central site outdoor sulfur concentrations. Linear and mixed-effects models were used to examine particle infiltration ratio-temperature relationships, based on which we incorporated projected meteorological values (Representative Concentration Pathways intermediate scenario RCP 4.5) to estimate particle infiltration ratios in 20-year future (2046–2065) and past (1981–2000) scenarios. ResultsThe mean particle infiltration ratio in Atlanta was 0.70 ± 0.30, with a 0.21 lower ratio in summer compared to transition seasons (spring, fall). Particle infiltration ratios were 0.19 lower in houses using heating, ventilation, and air conditioning (HVAC) systems compared to those not using HVAC. We observed significant associations between particle infiltration ratios and both linear and quadratic models of ambient temperature for homes using natural ventilation and those using HVAC. Future temperature was projected to increase by 2.1 °C in Atlanta, which corresponds to an increase of 0.023 (3.9%) in particle infiltration ratios during cooler months and a decrease of 0.037 (6.2%) during warmer months. DiscussionWe estimated notable changes in particle infiltration ratio in Atlanta for different 20-year periods, with differential seasonal patterns. Moreover, when stratified by HVAC usage, increases in future ambient temperature due to climate change were projected to enhance seasonal differences in PM2.5 infiltration in Atlanta. These analyses can help minimize exposure misclassification in epidemiologic studies of PM2.5, and provide a better understanding of the potential influence of climate change on PM2.5 health effects.

A Study of the chemical nature of sulfur-containing rocks and Frasch sulfur in the Al-Mishraq Sulfur field

The economic evaluation of the exploration sulfur well depends mainly on the elemental sulfur content and its association other factors, so a sample of sulfur rocks extracted by a special excavator for one of the exploratory wells was studied and in the form of a bore hole rock. The elemental sulfur ratio reached 12.8% an important ratio in estimating the explored sulfur reserves and through XRD, the predominant crystalline composition is calcite mineral with hexagonal crystalline form and with a lesser percentage in orthorhombic crystal sulfur this supports one of the theories that explained the formation of sulfur. Also, the mine Mishraq sulfur extracted by the underground melting method (known as the Frasch process) was studied chemically, and the elemental sulfur ratio reached 98.58% and the bituminous material 1.157%. Also, the SEM scanning electron microscope showed the presence of nanotubes of size (20-44 nm) belonging to the carb-sulfur compounds in the SEM, which are observed for the first time in this form.

Mineralogical and geochemical characteristics of altered volcanic ashes (tonsteins and K-bentonites) from the latest Permian coal-bearing strata of western Guizhou Province, southwestern China

Although the geochemical and mineralogical characteristics and provenance of Permian-Triassic boundary (PTB) widespread volcanic ashes from southern China have been well investigated, the volcanic ashes just prior to the end-Permian mass extinction (EPME) have rarely been studied. This paper presents the mineralogical and geochemical compositions of volcanic ashes from the latest Permian coal-bearing strata of southwest China. Based on the relative abundances of kaolinite and mixed-layer illite/smectite (I/S), the volcanic ashes in the present study can be divided into tonsteins and K-bentonites, which are dominated by kaolinite and I/S, respectively. The I/S in K-bentonites formed during burial diagenesis in a non-marine environment, indicated by their low contents of sulfur and low ratios of Sr/Ba. Based on the general geothermal gradient and vitrinite reflectance of coals, the I/S was deduced to have formed under a temperature less than 100 °C. Collectively, the occurrence of vermicular kaolinite, as well as high-temperature quartz and euhedral primary zircon identified in tonstein samples indicate an intermediate-felsic pyroclastic origin for the volcanic ashes, while rounded quartz and mica grains both in tonsteins and K-bentonites reflect the products of erosion from sediment source regions. The negative Eu anomalies, rare earth elements (REY) distribution patterns, low contents of Sc, V, Cr, Co, Ni and Zn, and Al2O3/TiO2 values, suggest that the tonsteins and K-bentonites are related to felsic volcanic eruptions. The relationship between Al2O3/TiO2 vs. Nb/Yb and Al2O3/TiO2 vs. Zr/TiO2 ratios indicate that the tonsteins and K-bentonites were derived from at least two felsic sources: (1) some distal volcanic arc(s) and (2) the top of the Kangdian Upland exposing the alkaline-felsic volcanic rocks formed during the waning activity of the Emeishan plume and the basement of the Kangdian Upland exposing older felsic rocks.

Tunable optical performance in nanosized AgInS2-ZnS solid solution heterostructures due to the precursor’s ratio modification

Solid solution AgInS2-ZnS nanostructures were prepared by reacting (Z)-1- (octadec-9-enyl)-3-phenylthiourea and 1-dodecanethiol with the corresponding metal linoleates. The combination of sulfur sources in modified ratios, which individually do not lead to significant results, resulted in the successful formation of nanorod-shaped heterostructures. The effect of sulfur source ratios on the structure, morphology, and optical properties of yellow-red emitting nanocrystals was systematically studied by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDS), X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM) analyzes. Nanocomposite materials based on polyvinyl toluene co-divinylbenzene (PVT-DVB) were investigated for each of the resulting nanostructures. It was demonstrated that even traces of nanomaterial (∼ 0.1 wt. %) provide a high photoluminescence quantum yield (PL QY up to 61.5%) of prepared nanocomposites.

Coupled relationships among anammox, denitrification, and dissimilatory nitrate reduction to ammonium along salinity gradients in a Chinese estuarine wetland

Salinization in estuarine wetlands significantly alters the balance between their nitrogen (N) removal and retention abilities but these processes have not yet been characterized effectively. In the present study, the potential rates of sediment denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) were mapped using N isotope tracing methods along salinity gradients across the Yellow River Delta wetland (YRDW) in China. The contribution of anammox to total dissimilatory N transformations in YRDW was merely 6.8%, whereas denitrification and DNRA contributed 52.3% and 40.9%, respectively. The potential rate of denitrification (5.82 μmol/kg/h) decreased significantly along salinity gradients and markedly exceeded DNRA potential rate (2.7 μmol/kg/h) in fresh wetlands, but was lower than that of DNRA in oligohaline wetlands (3.06 and 3.18 μmol/kg/h, respectively). Moreover, a significantly positive relationship between salinity and DNRA/denitrification was obeserved, indicating that increased salinity may favor DNRA over denitrification. Furthermore, total sulfur (TS) content and ratio of total organic carbon to total nitrogen (C/N) increased with the salinity gradient and showed evident positive relationships with the DNRA/denitrification ratio. In this study, we proved that increased salinization resulted in the dominance of DNRA over denitrification, possible through the addition of S and alteration of the C/N in estuarine wetlands, leading to increased N retention in estuarine wetlands during salinization, which would enhance the eutrophication potential within wetlands and in downstream ecosystems.

Probing Excitons in Ultrathin PbS Nanoplatelets with Enhanced Near-Infrared Emission.

Colloidal PbS nanoplatelets (NPLs) are highly interesting materials for near-infrared optoelectronic applications. We use ultrafast transient optical absorption spectroscopy to study the characteristics and dynamics of photoexcited excitons in ultrathin PbS NPLs with a cubic crystal structure. NPLs are synthesized at near room temperature from lead oleate and thiourea precursors; they show an optical absorption onset at 680 nm (1.8 eV) and photoluminescence at 720 nm (1.7 eV). By postsynthetically treating PbS NPLs with CdCl2, their photoluminescence quantum yield is strongly enhanced from 1.4% to 19.4%. The surface treatment leads to an increased lead to sulfur ratio in the structures and associated reduced nonradiative recombination. Additionally, exciton-phonon interactions in pristine and CdCl2 treated NPLs at frequencies of 1.96 and 2.04 THz are apparent from coherent oscillations in the transient absorption spectra. This study is an important step forward in unraveling and controlling the optical properties of IV-VI semiconductor NPLs.

Effect of slag composition on desulfurization during recycling rejected electrolytic manganese metal by electroslag remelting

To reduce the Mn vaporization during recycling rejected electrolytic manganese metal by electroslag remelting, it is proposed to reduce the temperature of molten slag pool, but which leads to the degradation of slag desulfurization. The desulfurization by interaction between CaF2–CaO–Al2O3–Na2O slag and rejected electrolytic manganese metal scrap was studied from the view of thermodynamics in this study. The results show that sulfur distribution ratio decreases with increase of CaF2 content, and increases with the increase of Na2O content and temperature. Na2O increases sulfur distribution ratio of slag by increasing CaO activity. Na2O addition in CaF2–CaO–Al2O3–Na2O slag can enhance desulfurization ability of slag due to the larger sulfur distribution ratio and lower viscosity. Thus, sulfur content in test of slag T3 bearing 45.8 wt% CaF2-23.2 wt% CaO-22.7 wt% Al2O3-8.3 wt% Na2O is much lower than that of slag without Na2O, implying that 45.8 wt% CaF2-23.2 wt% CaO-22.7 wt% Al2O3-8.3 wt%Na2O slag is the promising slag for recycling rejected electrolytic manganese metal by ESR.

Sulfur nanoparticles/Ti3C2Tx MXene with an optimum sulfur content as a cathode for highly stable lithium-sulfur batteries.

Lithium-sulfur batteries have a high theoretical energy density but they need better sulfur host materials to retain the lithium polysulfide shuttle effect, which results in the batteries' capacity fading. Titanium carbide MXene (Ti3C2Tx MXene) is an excellent host for the sulfur cathode because of its layered-stacked structure and many surface termination groups. The sulfur content in S/Ti3C2Tx MXene composites is an important factor affecting the cathodes' electrochemical performance. In this work, S/Ti3C2Tx MXene composites with different sulfur contents are prepared by a one-step hydrothermal process, and the influence of the sulfur content in the S/Ti3C2Tx MXene composite on the S/Ti3C2Tx MXene cathode's electrochemical performance is studied. When the mass ratio of sulfur to MXene in the reactant is 4 : 1, the sulfur nanoparticles are uniformly filled in the layered-stacked structure. The layered-stacked structure can buffer the volume expansion of sulfur during cycling and the surface termination groups exhibit strong adsorption of LiPSn. Thus, the S/MXene composite with an optimum sulfur content (67.0 wt%) demonstrates an excellent electrochemical performance, including a high initial reversible capacity (1277 mA h g-1 at 0.5 C) and the best cycling performance (1059 mA h g-1 at 0.5 C after 100 cycles). This work offers a guide to developing advanced S-based cathode materials with an appropriate S content for lithium sulfur batteries.