Bulk Sulfur Research Articles

Disproportionation of Inorganic Sulfur Compounds by Mesophilic Chemolithoautotrophic Campylobacterota.

The disproportionation of inorganic sulfur compounds could be widespread in natural habitats, and microorganisms could produce energy to support primary productivity through this catabolism. However, the microorganisms that carry this process out and the catabolic pathways at work remain relatively unstudied. Here, we investigated the bacterial diversity involved in sulfur disproportionation in hydrothermal plumes from Carlsberg Ridge in the northwestern Indian Ocean by enrichment cultures. A bacterial community analysis revealed that bacteria of the genera Sulfurimonas and Sulfurovum, belonging to the phylum Campylobacterota and previously having been characterized as chemolithoautotrophic sulfur oxidizers, were the most dominant members in six enrichment cultures. Subsequent bacterial isolation and physiological studies confirmed that five Sulfurimonas and Sulfurovum isolates could disproportionate thiosulfate and elemental sulfur. The ability to disproportionate sulfur was also demonstrated in several strains of Sulfurimonas and Sulfurovum that were isolated from hydrothermal vents or other natural environments. Dialysis membrane experiments showed that S0 disproportionation did not require the direct contact of cells with bulk sulfur. A comparative genomic analysis showed that Campylobacterota strains did not contain some genes of the Dsr and rDSR pathways (aprAB, dsrAB, dsrC, dsrMKJOP, and qmoABC) that are involved in sulfur disproportionation in some other taxa, suggesting the existence of an unrevealed catabolic pathway for sulfur disproportionation. These findings provide evidence for the catabolic versatility of these Campylobacterota genera, which are widely distributed in chemosynthetic environments, and expand our knowledge of the microbial taxa involved in this reaction of the biogeochemical sulfur cycle in hydrothermal vent environments. IMPORTANCE The phylum Campylobacterota, notably represented by the genera Sulfurimonas and Sulfurovum, is ubiquitous and predominant in deep-sea hydrothermal systems. It is well-known to be the major chemolithoautotrophic sulfur-oxidizing group in these habitats. Herein, we show that the mesophilic predominant chemolithoautotrophs of the genera Sulfurimonas and Sulfurovum could grow via sulfur disproportionation to gain energy. This is the first report of the chemolithoautotrophic disproportionation of thiosulfate and elemental sulfur within the genera Sulfurimonas and Sulfurovum, and this comes in addition to their already known role in the chemolithoautotrophic oxidation of sulfur compounds. Sulfur disproportionation via chemolithoautotrophic Campylobacterota may represent a previously unrecognized primary production process in hydrothermal vent ecosystems.

Fabrication of sulfur quantum dots via a bottom-up strategy and its application for enhanced fluorescence monitoring of o-phenylenediamine

Nowadays, the synthesis of luminescent sulfur quantum dots (SQDs) mainly depends on a top-down method, which requires abnormally long reaction time by etching bulk sulfur powder. To overcome this limitation, a facile bottom-up strategy has been provided to fabricate fluorescent SQDs enabled by the reaction between thioacetamide (TAA) and hydrogen peroxide (H2O2) using carboxymethyl cellulose (CMC) as a passivation agent. Herein, TAA acts as sulfur source to release sulfide ions (S2-), which react directly with H2O2 to generate element sulfur to assemble the CMC-stabilized SQDs (SQDs@CMC). The prepared SQDs@CMC emits blue fluorescence, and owns good water dispersibility, superior photostability, excitation dependent luminescence and a reasonable quantum yield up to 9.31 %. Herein, the prepared SQDs@CMC combined with Cu2+ has a sensitive response toward o-phenylenediamine (OPD) by forming ternary SQDs@CMC/Cu2+/OPD complex, which can emit enhanced blue-shift fluorescence. The fluorescence of the ternary complex is 10 times higher than that of SQDs@CMC and the proposed SQDs@CMC-Cu2+ assembly has been successfully used to monitor OPD in various waters with high selectivity. Therefore, this paper not only provides a bottom-up strategy to prepare SQDs, but also develops a novel fluorescence “turn on” sensing platform for OPD detection.

Bulk and amino acid isotope analyses of hair detail adult diets and infant feeding practices among pre- and post-maize populations of the northern Chilean coast of the Atacama Desert

This study investigates diet heterogeneity among Chinchorro and Inca adults and subadults living on the northern Chilean coast of the Atacama Desert before and after the introduction of maize cultivation. This is achieved by amino acid carbon isotope analysis and bulk carbon, nitrogen, and sulphur isotope analysis of 1-cm sequential segments of scalp hair from human remains deposited at the funerary sites of Morro 1 and 1–6 (Archaic Period) and Camarones 9 (Late Period).Results show that Chinchorro adults relied predominantly on marine resources and partially on wild plants. Inter-individual variability in diet was limited, indicating food redistribution between sexes. Childhood and adolescent diets were comparable to those of the adults. Partial breastfeeding was continued up to the age of 2–3 yrs. Subsequently, Inca adults relied on a combination of marine resources and maize. Intra- and inter-individual variability in diet was limited suggesting existence of a centralised system of food procurement and redistribution. Childhood and juvenile diets were comparable to those of the adults, except for two malnourished children being raised on maize.Amino acid δ13C analysis of hair keratin is proposed as a potential tool for reconstructing the nutritional status of an infant without population-specific maternal isotope baseline.

Therapeutic Delivery of Nanoscale Sulfur to Suppress Disease in Tomatoes: In Vitro Imaging and Orthogonal Mechanistic Investigation.

Nanoscale sulfur can be a multifunctional agricultural amendment to enhance crop nutrition and suppress disease. Pristine (nS) and stearic acid coated (cS) sulfur nanoparticles were added to soil planted with tomatoes (Solanum lycopersicum) at 200 mg/L soil and infested with Fusarium oxysporum. Bulk sulfur, ionic sulfate, and healthy controls were included. Orthogonal end points were measured in two greenhouse experiments, including agronomic and photosynthetic parameters, disease severity/suppression, mechanistic biochemical and molecular end points including the time-dependent expression of 13 genes related to two S bioassimilation and pathogenesis-response, and metabolomic profiles. Disease reduced the plant biomass by up to 87%, but nS and cS amendment significantly reduced disease as determined by area-under-the-disease-progress curve by 54 and 56%, respectively. An increase in planta S accumulation was evident, with size-specific translocation ratios suggesting different uptake mechanisms. In vivo two-photon microscopy and time-dependent gene expression revealed a nanoscale-specific elemental S bioassimilation pathway within the plant that is separate from traditional sulfate accumulation. These findings correlate well with time-dependent metabolomic profiling, which exhibited increased disease resistance and plant immunity related metabolites only with nanoscale treatment. The linked gene expression and metabolomics data demonstrate a time-sensitive physiological window where nanoscale stimulation of plant immunity will be effective. These findings provide mechanistic understandings of nonmetal nanomaterial-based suppression of plant disease and significantly advance sustainable nanoenabled agricultural strategies to increase food production.

New Smartphone based Colorimetric Method Development and validation for the Drugs containing Nitrogen, Sulphur and Phosphorus in Bulk and Tablet Dosage Form

A method for determining the concentration of coloured compounds in a solution is colorimetry. The intensity of the colour is related to the chemical concentration being measured. Because of their low cost and ability to collect, store, and interpret data all in one device, smartphone-based colorimetry has increased in popularity as an analytical tool. The camera on the phone is used as a detector in smartphone colorimetry. Both the smartphone colorimetric method and the UV method relied on the detection of colour intensity as concentration rose. Distinct oxidation states of ammonium metavanadate generate different colours depending on the oxidation state. The +5-oxidation state appears yellow, the +4-oxidation state appears blue, the +3-oxidation state appears green, and the +2-oxidation state appears purple. The ammonium metavanadate reagent is orange red in colour, but when it combines with pharmaceuticals that contain nitrogen, phosphorus, or sulphur in their structure, it turns green. The developed approach for all of the drugs in this article is linear. The colour intensity increases as the concentration of API increases. All of the photos were captured on a smartphone and analysed with photometrix PRO software. The photometrix PRO application turns an image to an RGB histogram, and it also includes regression models. The percent RSD for all three drugs was less than 2 employing Photometrix PRO and UV method. Using a statistical method called a two-paired test, the results reveal that both procedures are equally significant for all three drugs.
 Keywords: Uv spectrophotometry, Photometrix PRO, RGB Histogram, Sumatriptan Succinate, Gemifloxacin, Tenofovir disoproxil fumarate

Evidence for Seawater Retreat With Advent of Meghalayan Era (∼4200 a BP) in a Coastal Harappan Settlement

AbstractThe transformation of mature (urbanized) phase of the ancient Indus civilisation between ∼4200 and 3800 years Before Present (yr BP) overlaps with the beginning of the Meghalayan Age (∼4200 ± 100 yr BP). Though exact cause(s) for decline of urbanized Indus phase are not yet clear, researchers continue to debate whether monsoonal dryness was the sole cause or several other regional factors manifested in a compounding manner. Here, we show a regional relative sea level fall in the downstream area of Indus habitation (south‐western Gujarat region) which initiated at 4150 ± 230 and continued up to 3625 ± 200 yr BP. We provide a multi‐proxy (chronological, sedimentological, mineralogical, isotopic and elemental abundance) data set from a well‐dated vertical sediment trench from Lothal (ancient dockyard area of Indus era) to support this inference. Chief proxies used for inferring the relative sea level fall were bulk sediment carbon and sulfur contents along with their stable isotopes (δ13C and δ34S) and foraminiferal assemblage. The conspicuous shifts in majority of proxies hint at a lowering of sea stand at the regional level that likely dried this ancient Harappan dockyard (used for sea trade). Findings of our study possess implications for Holocene climate changes and their plausible impact(s) on Harappan trade and culture. Additionally, it invites evidences for large scale geological changes at ∼4200 yr BP distinct to the Meghalayan era.

Sulfides in Mercury's Mantle: Implications for Mercury's Interior as Interpreted From Moment of Inertia

AbstractThe partitioning of sulfur between Mercury's core and mantle reflects its formation conditions and early evolution. If Mercury's core and mantle equilibrated under reducing conditions, and if Mercury is not depleted in sulfur relative to chondrites, Mercury's mantle should contain large quantities (7–11 wt.%) of sulfur in the form of Ca or Mg‐rich sulfides. Using petrologic constraints, we estimate the quantity of these sulfides and the implications of a sulfide‐rich mantle for Mercury's radial density structure. We find that based on recent measurements of Mercury's outer shell moment of inertia (MoI), a sulfide‐rich, iron‐poor mantle mineralogy is consistent with a low value of Mercury's polar MoI (0.333 MR2). Alternatively, a higher value for Mercury's MoI (0.343 MR2) would require a sulfide‐poor mantle, indicating bulk sulfur depletion or more oxidizing conditions than implied by surface composition.

Bulk and grain-scale minor sulfur isotope data reveal complexities in the dynamics of Earth’s oxygenation

SignificanceThe permanent disappearance of mass-independent sulfur isotope fractionation (S-MIF) from the sedimentary record has become a widely accepted proxy for atmospheric oxygenation. This framework, however, neglects inheritance from oxidative weathering of pre-existing S-MIF-bearing sedimentary sulfide minerals (i.e., crustal memory), which has recently been invoked to explain apparent discrepancies within the sulfur isotope record. Herein, we demonstrate that such a crustal memory effect does not confound the Carletonville S-isotope record; rather, the pronounced Δ33S values identified within the Rooihoogte Formation represent the youngest known unequivocal oxygen-free photochemical products. Previously observed 33S-enrichments within the succeeding Timeball Hill Formation, however, contrasts with our record, revealing kilometer-scale heterogeneities that highlight significant uncertainties in our understanding of the dynamics of Earth's oxygenation.

Field-induced reagent concentration and sulfur adsorption enable efficient electrocatalytic semihydrogenation of alkynes.

Efficient electrocatalytic alkyne semihydrogenation with potential/time-independent selectivity and Faradaic efficiency (FE) is vital for industrial alkene productions. Here, sulfur-tuned effects and field-induced reagent concentration are proposed to promote electrocatalytic alkyne semihydrogenation. Density functional theory calculations reveal that bulk sulfur anions intrinsically weaken alkene adsorption, and surface thiolates lower the activation energy of water and the Gibbs free energy for H* formation. The finite element method shows high-curvature structured catalyst concentrates K+ by enhancing electric field at the tips, accelerating more H* formation from water electrolysis via sulfur anion–hydrated cation networks, and promoting alkyne transformations. So, self-supported Pd nanotips with sulfur modifiers are developed for electrochemical alkyne semihydrogenation with up to 97% conversion yield, 96% selectivity, 75% FE, and a reaction rate of 465.6 mmol m−2 hour−1. Wide potential window and time irrelevance for high alkene selectivity, good universality, and easy access to deuterated alkenes highlight the promising potential.

Co-exposure of sulfur nanoparticles and Cu alleviate Cu stress and toxicity to oilseed rape Brassica napus L.

Experiments were performed to explore the impact of sulfur nanoparticles (SNPs) on growth, Cu accumulation, and physiological and biochemical responses of oilseed rape (Brassica napus L.) inoculated with 5 mg/L Cu-amended MS medium supplemented with or without 300 mg/L SNPs exposure. Cu exerted severe phytotoxicity and inhibited plant growth. SNPs application enhanced the shoot height, root length, and dry weight of shoot and root by 34.6%, 282%, 41.7% and 37.1%, respectively, over Cu treatment alone, while the shoot and root Cu contents and Cu-induced lipid perodixation as the malondialdehyde (MDA) levels in shoots and roots were decreased by 37.6%, 35%, 28.4% and 26.8%. Further, the increases in superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR) and glutathione S-transferase (GST) enzyme activities caused by Cu stress were mitigated in shoots (10.9%–37.1%) and roots (14.6%–35.3%) with SNPs addition. SNPs also positively counteracted the negative effects on shoot K, Ca, P, Mg, Mn, Zn and Fe contents and root K, Ca, Mg and Mn contents from Cu exposure alone, and significantly promoted the nutrients accumulation in plant. Additionally, in comparison with common bulk sulfur particles (BSPs) and sulfate, SNPs showed more positive effects on promoting growth in shoots (6.7% and 19.5%) and roots (10.9% and 15.1%), as well as lowering the shoot Cu content (40.1% and 43.3%) under Cu stress. Thus, SNPs application has potential to be a green and sustainable technology for increasing plant productivity and reducing accumulation of toxic metals in heavy metal polluted soils.

In‐situ growth of ultrathin sulfur microcrystal on MXene‐based 3D matrice for flexible lithium–sulfur batteries

AbstractLithium–sulfur batteries (Li‐S batteries) are promising next‐generation energy storage systems because of their high‐theoretical energy density. However, the commercialization of Li‐S batteries is still impeded by the aggregation of sulfur, low‐sulfur utilization, shuttling of dissolved polysulfides and sluggish reaction kinetics. Herein, we designed a hierarchically maple leaf‐like structured sulfur electrodes by in‐situ growth of ultrathin sulfur microcrystal on two‐dimensional MXene‐graphene‐cellulose nanofiber (MGN) matrice (denoted as IS‐MGN@S). The sulfur microcrystal as cathode can achieve improved kinetics than bulk sulfur due to its few layers of sulfur atoms, which is proved by the density functional theory calculations. The MXene not only confines polysulfides through strong chemisorption but also promotes the catalytic conversion of polysulfides. The introduction of graphene improves the conductivity and boosts the immobilization and conversion of polysulfides. As a result, the IS‐MGN@S cathode demonstrates remarkable electrochemical properties with a high‐initial capacity (1229 mAh g−1 at 0.2C), substantial improvement in rate capability (770 mAh g−1 at 2C), and stable long‐term cycling capacity. Moreover, the pouch cells with IS‐MGN@S cathode and gel electrolyte demonstrate excellent mechanical properties under mechanical damage (nail & cut tests, severe deformations), suggesting their promising applications for wearable electronic devices.image

Manipulating time-dependent size distribution of sulfur quantum dots and their fluorescence sensing for ascorbic acid.

Unlike the previous commonly used strong alkaline solvent sodium hydroxide, we employ an eco-friendly solvent, ethanol, as a solvent for the preparation of ultra-small-sized sulfur quantum dots (SQDs). Ethanol can disperse bulk sulfur and allow sufficient transfer of large-sized sulfur to smaller-sized SQDs through a one-pot synthesis approach. The SQDs obtained from ethanol as the solvent displays superior photoluminescence properties to those in water and sodium hydroxide. By delicately controlling the reaction conditions, including the amount of bulk sulfur, the reaction time, and the proportion of sulfur to oxidizing reagent, highly blue emissive SQDs with a photoluminescence quantum yield (PLQY) of 7.04% with ultra-high stability for several months can be successfully prepared. Furthermore, we found out that the SQDs display a dynamic photoluminescence properties and varied particle sizes as the reaction time increases, which is possibly realized via the etching-aggregation process. Morevoer, the fluorescence of SQDs-72 can be effectively quenched by CoOOH nanosheets and recovered upon addition of ascorbic acid (AA) by consuming CoOOH nanosheets through the redox reaction, leading to fluorescence recovery. Therefore, a fluorescence "off-on" nanosensor for the detection of AA with a limit of detection (LOD) of 0.85 μM was constructed.

In situ growth of MOF-derived sulfur vacancy-rich CdS nanoparticles on 2D polymers for highly efficient photocatalytic hydrogen generation.

In heterojunction photocatalytic materials, the size of the nanoparticles and electron-hole separation efficiency have a great influence on the photocatalytic hydrogen production activity. In this work, for the first time, a strategy of combining sulfur vacancy engineering and quantum size control for constructing CdS (MOF)/PI heterojunctions was reported. Sulfur-deficient CdS (MOF) nanoparticles with a size of 5-10 nm were derived from in situ sulfurization of Cd-MOF precursors and highly dispersed on the surface of 2D polyimide (PI). The experimental and characterization results demonstrated that CdS (MOF)/PI heterojunctions possess broader and stronger light absorption towards the visible region than pristine PI. More importantly, a considerable amount of sulfur vacancies were introduced into CdS (MOF) nanoparticles. The presence of abundant surface and bulk sulfur vacancies created more unsaturated coordinated Cd 3c atoms, which increased the proportion of the (002) crystal planes that act as highly active crystal planes of CdS (MOF), providing more active reaction sites. The surface sulfur vacancy level located near the Fermi level serves as the photogenerated electron trap level, thereby increasing the efficiency of electron-hole separation and further prolonging the lifetime of photogenerated electrons. As a result, the 18%CdS(MOF)/PI heterojunction exhibited a higher hydrogen evolution rate of 8640 μmol g-o after 4 hours of illumination, which was 20 times higher than that of 18%CdS/PI under visible light irradiation. This work highlights the role of sulfur defects in the modification of the CdS (MOF)/PI heterojunction as a feasible strategy for improving charge separation and photocatalytic performance.

An exploration of benchtop X‐ray emission spectroscopy for precise characterization of the sulfur redox state in cementitious materials

The evolution of sulfur chemistry in cements is best known in the bailiwick of failure mechanisms via sulfate attack, but is equally important for its contributions to the reduction capacity of cementitious materials often used for immobilizing nuclear waste streams destined for long‐term storage, for example, cementitious waste forms (CWF). The total reduction capacity of CWFs, encompassing contributions from both S and Fe reductants, and its implications toward radionuclide immobilization is most often studied by destructive wet chemistry methods requiring acid digestion in the presence of Ce(IV) and subsequent titration and colorimetric interpretation. Here, we investigate a similarly analytical but nondestructive alternative, benchtop high resolution wavelength‐dispersive X‐ray fluorescence spectroscopy, most commonly known as X‐ray emission spectroscopy (XES), for probing the bulk sulfur oxidation state distribution. We present here an initial investigation of S XES, including an improved experimental protocol for lab XES of inhomogeneous samples, both as a complement to the Ce(IV) test and for new scientific opportunities that it enables for observing changes in sulfur chemistry. We discuss future improvements and opportunities, including: (1) the practical challenges associated with coordinating XES and Ce(IV) liquid extraction for a more comprehensive perspective on reduction capacity and for a high‐precision evaluation of uncertainties in the Ce(IV) test; and (2) new opportunities, due to the nondestructive nature of XES, for controlled evolution studies aimed at elucidating specific chemical responses of CWFs exposed to invasive gas or liquid species or to accelerated aging by radiative dose or thermal treatment.

Pellet Production from Residual Biomass of Greenery Maintenance in a Small-Scale Company to Improve Sustainability

Replacing fossil energy sources with renewable energy sources is a key strategic action to limit environmental issues. To achieve this goal, substitution with biomass is beneficial due to its versatility in various fields. In terms of circular economy and sustainability, the possibility of energy exploitation of residual biomass is particularly desirable in small-medium enterprises. The use of supply chain by-products can improve sustainability and create opportunities for companies. The purpose of this study is to evaluate the suitability of residual biomass of conifers and broad-leaved trees to produce quality pellets using an agri-pellet machine activated by the power take-off of a tractor. This system can be employed at the farm level. Wood biomass of four species was tested; poplar, stone pine, black locust, and oak. Wood chips samples were analyzed to determine their qualitative characteristics following the technical standard ISO 17225-4. Based on the results, different wood blends were created to produce pellets, subsequently characterized according to ISO 17225-2. The analyses carried out on wood chips and pellets were bulk density, moisture, ash content, calorific value, elemental composition, chlorine, sulfur, and heavy metals. In addition, particles size was measured only for wood chips, while the length, diameter, mechanical durability, and ash melting behaviors were determined only for pellets. Some of the analyzed mixtures show acceptable values according to the current ISO technical standards. The values related to the apparent pellet bulk density and the durability test highlight that not all the mixtures are suitable to produce quality pellets. Results also represent a good starting point for future studies.

Sulfur/phosphorus doping-mediated morphology transformation of carbon nitride from rods to porous microtubes with superior photocatalytic activity

Hetero-atoms doping or morphology controlling of carbon nitride (g-C3N4) can availably regulate its electronic band structure and optimize photocatalytic performance under visible light. Herein, sulful (S), phosphorus (P) co-doped porous carbon nitride microtubes (SPCN) was synthesized by using ammonium dihydrogen phosphate and melamine as precursors, in which ammonium dihydrogen phosphate can not only control the morphology of carbon nitride from nanorods to porous microtubes, but also provide a potential P source for P-doped CN. The prepared SPCN0.1 with the content of 0.1 g ammonium dihydrogen phosphate displayed the highest photocatalytic hydrogen generation rate of 4200.3 µmol g-1h−1, which was approximately 25 and 1.6 folds by bulk g-C3N4 (CN) and sulphur doped g-C3N4 microrods (SCN), respectively. Moreover, the apparent quantum efficiency of HER reached up to 10.3 % at 420 nm. The enhanced photocatalytic performance may be attributed to the synergistic effect of S, P doping and morphology structure of carbon nitride, which effectively accelerated the separation and transfer of photogenerated electron-hole pairs, proved by photoluminescence spectra, time-resolved PL spectra, electrochemical impedance spectrum and transient photocurrent responses. The novel synthetic method described in this paper is an effective approach to regulate the morphology of g-C3N4via non-metal doping with superior photocatalytic performance.

Sulfur nanoparticles improved plant growth and reduced mercury toxicity via mitigating the oxidative stress in Brassica napus L.

Experiments were conducted to determine the effects of sulfur nanoparticles (SNPs) on alleviating mercury (Hg) toxicity and accumulation in Brassica napus L. in MS medium. The results demonstrated that 10 mg/L Hg severely inhibit brassica seedlings growth, whereas the addition of 300 mg/L SNPs alleviated Hg toxicity, and dry weight were improved by 42.4% (shoot) and 37.8% (root) compared to 10 mg/L Hg treatment alone. SNPs application decreased Hg accumulation in roots and shoots by 6–10 folds. Comparatively, the effect of corresponding bulk sulfur particles (BSPs) and sulfate as ionic compound for counteracting Hg toxicity and accumulation was less pronounced than SNPs treatment. Co-exposure of SNPs along with Hg also alleviated the Hg-induced oxidative stress as the MDA and H2O2 contents, antioxidant enzymes activities (SOD, POD, APX and GST) and glutathione (GSH) content in roots and shoots were decreased relative to Hg treatment alone. The macro (K, Ca, P, Mg) and micronutrients (Zn, Mn, Fe) concentrations in roots and shoots were elevated considerably by SNPs co-exposure compared to plants exposed to Hg only. Further, the expression of selected genes encoding the antioxidant enzymes and nutrient transporters also showed changes similar to the physiological and biochemical parameters. Our results showed that SNPs play a significant role in the decreasing Hg accumulation, counteracting the Hg toxicity, and enhancing plant biomass and nutrients accumulation in B. napus. These findings will be helpful in developing strategies to decrease heavy metals contamination in the food chain as well as for phytoremediation applications.

Enabling stable sodium metal cycling by sodiophilic interphase in a polymer electrolyte system

Enabling highly reversible sodium (Na) metal anodes in a polymer electrolyte (PE) system is critical for realizing next-generation batteries with lower cost, higher energy, and improved safety. However, the uneven Na deposition and high Na/PE interphase resistance lead to poor reversibility and short cycle life of Na metal anodes. To tackle these problems, here a variety of metal nanoparticles (M-np, M = Al, Sn, In or Au) are deposited onto copper (Cu) foils to synthesize binder-free M-np@Cu substrates for Na plating/stripping. Notably, the Au-np@Cu substrate provides abundant preferential nucleation/growth sites, decreasing Na nucleation barrier and thus promoting uniform Na deposition. Accordingly, stable Na metal anodes are achieved with high reversible capacities, long cycle life, and high usage of Na. With the Au-np@Cu/Na anode and PE, the full cell using a commercial bulk sulfur cathode exhibits a reversible capacity of >400 mAh g−1 with near-100% Coulombic efficiency over 200 cycles.

Chlorine and sulfur evolution in magmatic rocks: A record from amphibole and apatite in the Tonglvshan Cu-Fe (Au) skarn deposit in Hubei Province, south China

In order to trace chlorine and sulfur evolution during magma evolution, detailed petrographic observation, major- and trace-element analysis of amphibole and apatite were carried out on the ore-related pluton in the Tonglvshan Cu-Fe (Au) skarn deposit, Hubei Province, South China. Several generations of apatite and amphibole are identified, from early to late including: (1) apatite in euhedral amphibole; (2) euhedral amphibole; (3) apatite in subhedral-anhedral amphibole/plagioclase; (4) subhedral-anhedral amphibole + plagioclase; (5) apatite in K-feldspar or quartz; and (6) K-feldspar + quartz. Most apatites show homogeneous textures, but a few apatite grains enclosed in amphibole and plagioclase (1 and 3) display oscillatory zoning. These zoned apatites crystallized in semi-closed environments created as growth of amphibole or plagioclase removed components of the melt. The magmatic Cl and S evolution can be divided into three stages: (I) In the deep magma chamber, at ∼ 5 km below the surface, magma underwent ∼ 39% fractional crystallization, and its Cl and S contents increased simultaneously; (II) In a shallow magma chamber at ∼ 2.5 km depth, fractional crystallization elevates Cl and S contents in the residual melt, but fluid exsolution depletes them; (III) At near-solidus stage, when fluid exsolution becomes weak, crystallization elevates Cl and S contents in the residual melt simultaneously. This study suggests that the silicate mineral (fractional) crystallization can elevate Cl content in residual melt, and fluid exsolution can efficiently remove Cl from the magma. Bulk sulfur in magma may be transported not only as dissolved sulfur, but also as sulfates like anhydrite. The sulfur content of apatite is controlled by the sulfur composition in melt from which the apatite crystallizes, but Cl in apatite may represent re-equilibration between the apatite and the last melt in contact with the apatite, because of rapid diffusion of Cl in apatite. These characteristics along with complex apatite generations imply that in-situ study is necessary when using apatite to trace volatile composition in magma.

Dual Functional Hydrogen Peroxide Boosted One Step Solvothermal Synthesis of Highly Uniform Sulfur Quantum Dots at Elevated Temperature and Their Fluorescent Sensing

The dual functional hydrogen peroxide (H2O2) assisted strategy for preparation of homogeneously distributed sulfur quantum dots (SQDs) with tunable size and prominent photoluminescence (PL) property is originally proposed via a one-pot solvothermal method. The synthesis of SQDs was demonstrated by treating sublimated sulfur powder and polyethylene glycol-400 (PEG-400) in the presence of H2O2 at elevated temperature. The H2O2 acts as a dual-functional reagent which could suspend the sulfur powder and etching bulk sulfur to construct uniform SQDs. At elevated temperature, the sulfur powder are easily transformed to molten sulfur which simultaneously acts as solvent. The as obtained SQDs exhibit a uniform size distribution, excellent PL properties with quantum yields (QYs) up to 10.3 %, superior dispersibility, and eminent photo stability. Moreover, morphology and element characterization reveal that the surface of spherical SQDs equipped with abundant oxidized sulphur species, while the diversification in the PL and QYs of SQDs under different reaction time are derived from the difference in their particle size which is proposed by the etching-assemble-etching process. Finally, the resultant SQDs was utilized as a sensitive iron ions (Fe3+) sensor with limit of detection (LOD) up to 10.80 nM as well as their investigation for fluorescent cellular imaging.