Sulfur Ratio Research Articles

Seasonal variation and secondary formation of size-segregated aerosol water-soluble inorganic ions in a coast megacity of North China Plain

The aerosol samples of water-soluble inorganic ions (WSIs), including SO42-, NO3-, NH4+, Cl-, K+, Na+, Ca2+, and Mg2+ in size-segregated particulate matter (PM), were collected by an Anderson sampler (with 8 nominal cut-sizes ranged from 0.43 to 9.0 μm) in urban Tianjin during 2013-2014. The results showed that particulate matters in the fine mode (PM2.1, Dp < 2.1 μm) comprised large part of mass concentrations of aerosols, and the water-soluble ionic species in the fine mode were 47.07 ± 14.29 μg m-3 (spring), 67.87 ± 28.74 μg m-3 (summer), 86.60 ± 48.53 μg m-3 (autumn), and 104.16 ± 51.76 μg m-3 (winter), respectively, which accounted for 59.5%, 63.3%, 71.9%, and 71.4% of the PM2.1 mass concentrations. Secondary pollutants of SO42-, NO3-, and NH4+ (SNA) were the dominant contributors of WSIs, which showed a bimodal size distribution in each season, with the larger peak appeared in the size fraction of 0.65-1.1 μm and the smaller one in 3.3-5.8 μm fraction. SNA concentrations in lightly polluted days (LPD) and heavily polluted days (HPD) were observably higher than non-polluted days (NPD), especially in the fine mode, with the peak diameter moving from 0.43-0.65 μm on NPD to 0.65-1.1 μm on LPD and HPD. The correlation analysis between NH4+, NO3-, and SO42- suggested that almost all SO42- and NO3- for fine particles had been completely neutralized by NH4+, and primarily existed in the forms of (NH4)2SO4 and NH4NO3. The sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) on LPD and HPD in fine mode were observably higher than those on NPD, especially in the range of 0.65-1.1 μm and 1.1-2.1 μm. Furthermore, SOR and NOR values in the size fraction of 0.43-3.3 μm increase as the RH elevated, especially in 0.43-2.1 μm, where RH was significantly positive correlated with SOR and NOR, indicating the significant contributions of heterogeneous processes to the secondary formation of SO42- and NO3-. These results suggested an enhanced formation ability of secondary pollutants under high RH in the coast city. Therefore, controlling the precursors of SNA, such as SO2 and NOx, would be more effective to reduce the fine particulate pollution in the coast megacity of Tianjin.

Effect of sulphur and zinc fertilization on productivity and economics of sesame (Sesamum indicum L.) in semi-arid conditions of Rajasthan

A field experiment was conducted at Agronomy farm, S.K.N. College of Agriculture, Jobner, Jaipur (Rajasthan) during kharif season of 2018 to study the effect of sulphur and zinc fertilization on productivity and economics of sesame. The experiment comprising of four levels each of sulphur (0, 15, 30 and 45 kg/ha) and zinc (0, 10, 20 and 30 kg zinc sulphate/ha), thereby making 16 treatment combinations was laid out in factorial randomized block design and replicated thrice. Results showed that progressive increase in level of sulphur up to 30 kg/ha significantly increased the most of the yield attributing characters of sesame viz., number of capsules/plant, number of seeds/capsule and test weight over preceding levels. It also recorded significantly higher seed yield (712 kg/ha) of sesame over control and 15 kg/ha and found at par with 45 kg/ha. Result further showed that every increase in level of zinc sulphate up to 20 kg/ha by and large significantly improved most of the yield determining characters of sesame over lower levels. It also recorded significantly higher seed yield (725 kg/ha) over control and 10 kg/ha and found at par with 30 kg/ha. The results further showed that according to economic and marginal analysis, progressive increase in level of sulphur upto 30 kg S ha-1 and zinc 20 kg Zn ha-1 seemed highly practical due to higher net returns, benefit cost ratio (BCR) and optimum dose of sulphur and zinc for sesame crop were computed as 39.24 kg S ha-1 and 26.30 kg Zn ha-1, respectively.

Pyritization of Rocks in Black Shale/Host Rock Transition Zones: Evidence from the Bazhenov Formation, Western Siberia

A complex of lithological-geochemical studies was carried out in rocks of the Upper Jurassic–Lower Cretaceous Bazhenov Formation and their transition zones to host rocks: composition of rocks, ratio of organic carbon and sulfide sulfur (C/S values), and distribution of several redox indicators (degree of pyritization, content of the authigenic uranium, and values of Mn/Al and Mo/Mn ratios). Morphology of pyrite was examined with a scanning electron microscope. Two main types of pyrite were revealed: (a) framboidal pyrite formed during early diagenesis with the participation of bacterial activity; (b) cryptocrystalline pyrite formed during diagenesis (early stage included) and, presumably, mesocatagenesis, i.e., medium substage of catagenesis. It was established that some part of the cryptocrystalline pyrite predated the framboidal variety. Pyritization of rocks with the cryptocrystalline pyrite formation took place at the lower and upper boundaries of the Bazhenov Formation in the over- and underlying rocks, where the low-carbon pyritic rocks are formed. Intense pyritization is also observed in the high-carbon rocks near the top of the Bazhenov Formation, where the pyrite–kerogen rocks are formed. Both low-carbon pyritic and pyrite–kerogen rocks are characterized by C/S 2. The low-carbon pyritic and pyrite–kerogen rocks occur near boundaries of the lithologically different members (mainly biogenic rocks in the Bazhenov Formation and terrigenous varieties in the host rocks) that were deposited under different redox conditions existing in the water column and near the marine paleobasin floor. Boundaries of such members could serve as geochemical redox barriers at late stages of lithogenesis. The pyritic and pyrite–kerogen rocks were likely pyritized during diagenesis because of the deposition of pyrite on the geochemical redox barriers from fluids that contained iron sulfides and migrated from the high-carbon Bazhenov sequence. Presumably, pyritization continued during the catagenesis owing to thermogeochemical processes of the organic matter transformation.

Controlled Phase and Porosity of Cobalt Disulfide Nanoparticles through Metal-Organic Frameworks As Efficient Bifunctional Electrocatalysts for Overall Water Splitting

With growing demands for sustainable energy sources, hydrogen energy is receiving great attention due to their abundant, eco-friendly, and renewable nature. Although water electrolysis is most promising technologies for hydrogen production, it is currently obstructed by the sluggish kinetic of oxygen evolution reaction (OER) compared with hydrogen evolution reaction (HER). Furthermore, according to the demand for simplicity and cost effectiveness of electrolysis, the need for bifunctional electrocatalysts which operate in the same electrolyzer, is rapidly increasing. The cubic pyrite-phase transition metal dichalcogenides, such as FeS2, NiS2, and CoS2, have been proposed as candidates for bifuctional electrocatalysts. Among them, CoS2 has been reported to exhibit high conductivity and high activity for HER and OER in strong alkaline condition.In this study, while there are many phases of cobalt sulfide (e.g., CoS, Co9S8, and CoS2 etc.), it was successfully controlled cobalt sulfide phase according to the sulfur ratio through predicted synthesis based on thermodynamic. A highly porous CoS2 nanoparticles (NPs) was directly synthesized by controlling the ratio of sulfur and cobalt Prussian blue analogues (Co3[Co(CN)6]2), one of the metal organic frameworks (MOFs). MOF-driven CoS2 could lead to improvements in catalytic activity. The newly-designed MOF-driven CoS2 OER, HER catalysts show distinct strong points. First, CoS2 is as one of transition metal compounds and has high catalytic activity. Furthermore, the CoS2 of this work shows a highly porous and uniform particle size because it was synthesized through MOFs using precipitation.The Co3[Co(CN)6]2 was used as the starting material before sulfurization. The Co3[Co(CN)6]2 was prepared through a facile precipitation method. The CoS2 NPs were synthesized through gas-solid reaction in vacuum system. A 5 mL size ampoule containing total 45 mg of a 2:1 mixture of Co3[Co(CN)6]2 and sulfur powders was arranged, then the ampoule was vacuumed to 10-2 torr. The prepared ampoule was annealed at 500 ℃ for 2 hr in a furnace at ramping rate of 5 ℃ min-1. The average powder size of synthesized CoS2 NPs was approximately 30 nm with ~ 4nm pores, resulting in a large surface area of 915.6 m2 g-1. Compared to commercial IrO2, CoS2 NPs showed exceptional performance. The synthesized catalysts achieved a catalytic current density of 10 mA cm-2 at overpotentials as low as 300, 200 mV from oxygen, hydrogen evolution polarization curves through linear sweep voltammograms (LSVs). Furthermore, it has outstanding long-term durability under 10 mA cm-2. The electrochemical performance was conducted with three electrode cell using 1.0 M KOH electrolyte and Pt counter electrode, and working electrode is ink type on Ni foam. Furthermore, MOF-driven CoS2 was conducted through a full-cell test of overall water splitting for a practical two-electrode system in 1.0 M KOH. It exhibited an overpotential of 1.65 V at 10 mA cm-2. We introduced MOFs to a new methodology based on thermodynamic processes. It showed the possibility of replacing noble metals such as Ir, Ru in terms of catalytic performance.

Impact of low temperature sulfur exposure on the aging of small pore Cu-zeolite SCR catalyst

This study investigated the impact of low temperature sulfur exposure prior to hydrothermal aging on the catalytic structure and performance of Cu-SSZ-13 catalyst toward NH3-SCR reaction. The sulfur exposure temperature, duration and the sequence of sulfur exposure vs. hydrothermal aging are investigated. All samples hydrothermally aged in presence of SOx (SO3/SOx = 0.7) have showed decreased activity compared to the sample aged hydrothermally only, but the extent of deactivation varies with different sulfur exposure conditions. The sulfur exposure at 200 °C for 100 hours prior to HTA has the most pronounced impact on the population of active site (Cu) and the SCR performance at low temperatures. And the sample of equivalent thermal and sulfur exposure but with the HTA prior to the sulfur exposure, has less decreases in the active Cu sites and less sulfur stored. In contrast, sulfur exposure at high temperature, e.g. 650 °C, has the least impact on the Cu-SSZ-13 catalyst. The molar ratio of stored sulfur to the decrease amount of active Cu sites is close to 1:1 ratio, which implies the deactivation of sulfur exposed catalyst is mainly due to the decrease of active Cu population. Furthermore, DRIFTs demonstrated that both Z2Cu and ZCuOH sites decrease in most cases and ZCuOH is more impacted compared to Z2Cu. With these findings, we concluded that low temperature sulfur exposure prior to HTA treatment leads to accelerated aging. Further characterization reveals that the aging is mainly due to the decrease in the population of active Cu sites. The finding suggests that a hydrothermal pretreatment before sulfur exposure of Cu-SCR catalyst can retard the deactivation of catalyst to a limited extent in the real-world application.

Sulfur copolymers (SDIB) from inverse vulcanization of elemental sulfur (S8) for polymer blend

Elemental sulfur (S8) is largely available resource as by-product from petroleum refining process which is causing “excess sulfur problem’ due to its limited usage. The utilization of sulfur as valuable material will not only address environmental concerns but provide cost-effective ways of consuming this huge amount of waste to develop new high-value, high-volume products. One facile synthetic method of utilizing sulfur directly as feedstock to produce polymeric material is inverse vulcanization. In this study, sulfur copolymers (SDIB) was synthesized via inverse vulcanization from S8 and processed into polymer blend with component polymers, polybenzoxazine (PBz) and poly(methyl methacrylate) (PMMA) to show its potential processability into polymer blend. Initially, synthesis of SDIB with varying feed ratios of sulfur to comonomer 1, 3-diisopropenylbenzene (DIB) was evaluated for its resulting properties. Spectroscopy showed copolymerization reactions occurred based on the change in characteristic absorption peaks (C=C-H, C=C, C-H) present in the spectra. Thermogravimetric analysis (TGA) indicated that SDIB is more thermally stable with the increase in onset temperature of degradation. Differential scanning calorimetry (DSC) profile exhibited new single glass transition temperature (Tg) that slightly increased with higher DIB ratio indicating evolution of microstructures of copolymers produced. The processability of SDIB into polymer blend was investigated by using SDIB (50 wt% S) with PBz and PMMA. Blending process using simple mixing technique with solvents was carried out for SDIB/PBz (10/10 wt%) and SDIB/PMMA (7.65/7.65 wt%) blend compositions. The results of this study demonstrated that polymercopolymers interactions influenced the phase structure and behaviour with polymer blend of SDIB/PBz showing higher degree of miscibility with more homogeneous and transparent blend as compared to SDIB/PMMA blend. The suitability of polymer blend in electrospinning of nanofibers could provide variety of new applications for SDIB.

MODERN ANALYSIS METHODS USE IN ORDER TO ESTABLISH THE GEOGRAPHIC ORIGIN OF FOOD PRODUCTS

Food products with controlled geographical origin place are in special demand among consumers because of their specific properties, due to climatic, soil characteristics or other factors. The article provides an analysis of regulatory framework for legal goods protection with an indication of their origin place on the territory of the Russian Federation and in other countries. Existing authentication methods for this type of product are reviewed. Based on the analysis of scientific literature, the authors noted the most significant works aimed at confirming the authenticity of food products’ origin place on the example of honey and meat products, which were carried out in the countries of the European Union, Australia, China, Brazil, South Africa, the USA and other countries. It is shown that the most widespread researches aimed at studying values of isotopic ratios of hydrogen ( 2 H/ 1 H), carbon ( 13 C/ 12 C), oxygen ( 18 O/ 16 O), nitrogen ( 15 N/ 14 N) and sulfur ( 34 S/ 32 S) in compounds contained in products that reflect the distribution of «light» and «heavy» isotopes during biological and geochemical processes within a single region. The analysis of the works aimed at studying the qualitative and quantitative composition of trace elements and rare earth metals (As, B, Ba, Cd, Li, Mn, Pd, Rb, Se, Te, Tl, Dy, U, etc.), as well as research of isotopic relations values of some elements ( 87 Sr/ 86 Sr, 207 Pb/ 206 Pb, etc.) in product samples and soils of studied region. The advantages of an integrated research approach, which includes the creation of data array of various indicators values and its in-depth analysis using chemometric algorithms and mathematical modeling methods, are shown.

Effects of minerals and Fe3+ on sulfur removal and its release behavior during coal pyrolysis under different atmospheres

Yunnan anthracite coal (YN) with high FeS2, Pingshuo coal (PS) with high organic sulfur and Duerping coal (DEP) with 33.52% organic and 64.20% inorganic sulfur were selected to investigate the effects of minerals and Fe3+ on sulfur release behavior during coal pyrolysis under Ar and 3% O2–Ar atmospheres by pyrolysis connected with gas chromatogram (Py-GC) combined with pyrolysis coupled with mass spectrometer (Py-MS). It is found that the sulfur removal ratios and the total amount of sulfur-containing gases release of coal samples under 3% O2–Ar atmosphere are higher than those under Ar atmosphere, indicating that O2 participates in coal pyrolysis process. The effects of minerals on sulfur removal are affected by these coals types. However, effects of Fe3+ on sulfur removal are related to atmospheres. During pyrolysis, Fe3+ is beneficial for all sulfur compounds to decompose at lower temperature under 3% O2–Ar atmosphere, while inhibits sulfur removal under Ar atmosphere. The minerals in coals can absorb sulfur gases. However, Fe3+ can significantly promote COS and SO2 release at lower temperatures under both atmospheres. But Fe3+ inhibits H2S release under Ar atmosphere.

Sulfidization processes in seasonally hypoxic shelf sediments: A study off the West coast of India

Continental shelves are the major sites for organic carbon burial and sulfate reduction. Organic carbon degradation and sulfidization along continental shelves are expected to play a significant role in global carbon-sulfur-iron (C–S–Fe) cycles. Here we report sediment pore-water chemistry and iron-sulfur speciation in two short cores SSK-42/9 and 10 collected off Malvan from the seasonally hypoxic shelf region off the west coast of India (WCI) at water depths of 30 and 13 m respectively. Concentration profiles of pore-water SO 4 2− , NH 4 + , DIC, ΣHS − and depth-integrated sulfate reduction rates (J SO4 ) suggest a variable influence of sedimentation rates, the composition of organic matter (marine and terrestrial) and anaerobic oxidation of methane (AOM) on the pore-fluid chemistry. Chromium reducible sulfur (CRS) and organic-bound sulfur (OBS) are the detectable solid-phase sulfur species in the studied sediment cores. Sulfur content and isotope ratios of chromium reducible sulfur (CRS) and organic-bound sulfur (OBS) phases produced via HS − /S x 2− pathways (sulfidization and sulfurization) show contrasting profiles in SSK42/9 and 10, apparently influenced by the availability of reactive iron, the relative significance of early and late diagenetic processes, source of OBS (detritus of marine origin and sulfurized organic molecules) and diffusion of ΣHS − produced via AOM across the SMTZ. The marked influence of AOM-driven sulfate reduction and the diffusion of isotopically enriched hydrogen sulfide across the sulfate-methane transition zone (SMTZ) is apparent from the δ 34 S CRS profiles in SSK-42/10. Sediment TOC/TS ratios recorded in this study are significantly less than that of average modern marine surface sediments (2.8:1) underlying oxygenated water and this is attributed to the enhanced sulfidization and burial of iron-sulfur minerals in the seasonally hypoxic regions. Since the inner shelf of WCI experiences seasonal alternation from normoxia to hypoxia which may have a profound influence on the benthic community structure, nature, and depth of bioturbation/bioirrigation, we propose that the impact of these processes need to be studied at a significantly higher resolution for better understanding C–S–Fe biogeochemical cycle. • The seasonally hypoxic shelf sediments play important role in C–S–Fe biogeochemical cycle. • Depth-integrated sulfate reduction rates off the west coast of India, show marked spatial variation. • δ 34 S CRS and δ 34 S OBS profiles show marked spatial variability and contrast with δ 34 HS .

Micro‐Mesopores Nitrogen‐Doped Carbon Combined Polar‐MoS2 as Host for High‐Performance Li‐S Batteries

AbstractA composite of MoS2/MMNC (micro‐mesopores nitrogen‐doped carbon) was prepared through a simple hydrothermal method and utilized as a host for Li−S battery. The crystal structure of MoS2/MMNC−S composite were tested by X‐ray diffraction (XRD), Raman Spectroscopy and X‐ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize its morphology. The pore size distribution and weight ratio of sulfur were measured via N2 adsorption‐desorption isotherm and thermogravimetric analysis (TGA), respectively. MoS2/MMNC−S composite showed a good electrochemical performance as the positive electrode for Li−S battery. The rate performance of the battery is ideal and the capacity retention is maintained at ∼ 90% after 200 cycles at 0.5 C.

Hydrothermal synthesis of monocopper sulfide for hydrogen peroxide-assisted photodegradation of paraquat

Copper sulfide was prepared by a hydrothermal method at 130°C. The copper to sulfur molar ratio (6-10) and ageing time (24-72 h) were their synthesis parameters. The obtained materials were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscope (TEM), UV-DR spectroscopy and X-ray photoelectron spectroscopy (XPS). In order to obtain monocopper sulfide, CuS, named as covellite, the molar recipe ratio of sulfur to copper should be less than 8 in any hydrothermal ageing time. The morphology showed spherical-like structure with energy band gap of 1.88-2.04 eV. CuS was tested for its photocatalytic degradation of paraquat under visible light irradiation. It exhibited excellent activities in the presence of H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;. The kinetic of paraquat degradation was also investigated using Langmuir-Hinshelwood-Hougen-Watson (LHHW) model. The reaction rate constant was three times higher than TiO&lt;sub&gt;2&lt;/sub&gt; under the same studied conditions.

Application of bag filter in integrated technology of dry desulfurization and dust collection

A new technical route is explored to realize the integrated design of dry gas desulfurization and dust collection, combining dry duct injection technology with bag filter technology. Sodium bicarbonate (NaHCO3) was used as desulfurizer, outside and inside filtration bag filters were used as the main body of the reaction device. A series of experiments were carried out, and the temperature, NaHCO3 particle size, inlet SO2 concentration, sodium to sulphur ratio and dust concentration were evaluated. The results showed that the desulfurization reaction was mainly composed of two parts: the NaHCO3 injection section of duct and the filtration of bag filter. The desulfurization efficiency of the inside filtration was better than that of the outside filtration, and collection efficiency was maintained above 99.9%. From 130°C to 150°C, the desulfurization efficiency of both inside and outside filtration bag filter increased with temperature increased, but the efficiency decreased at the temperatures of 150°C∼200°C because of the thermal decomposition reaction of sodium bicarbonate. After adding 1000mg·m−3 dust, the desulfurization efficiency of both the inside filtration and outside filtration bag filters increased by 10%, and the trend of desulfurization efficiency with temperature was the same as that before adding dust. It was found that the desulfurization reaction was better with the NaHCO3 particles size was smaller, and the inlet SO2 gas concentration had little effect on the desulfurization efficiency.

Mercury sulfide thin film deposition using [HgI4]2− complex ions

The optimal conditions for the growth of HgS films through the chemical bath deposition technique, using iodine as a complexing agent, are explored here, which has potential in semiconducting devices, for a diversity of applications. Some concentration variations were proposed to observe their effect on deposition, by changing the concentration ratios of sulfur and iodine to mercury. Variations were such that increasing iodine decreased sulfur, with mercury varying from 4.3 to 8.3%, relative to ([Hg]+[S]+[I]) content. It was observed that these variations control the heterogeneous reaction in different ways: increase in iodine concentration promotes the heterogeneous nucleation of HgS by the formation of [HgI4]2− complex ions; higher sulfur than iodine content degrades deposition; and doubling mercury concentration leads to a more uniform thin film. In addition, it was found that the used parameters generate films with predominant meta-cinnabar phase, and under certain conditions, the growth of cinnabar grains in preferential orientation can be favored.

A Lithium Oxythioborosilicate Solid Electrolyte Glass with Superionic Conductivity

AbstractAs potential next‐generation energy storage devices, solid‐state lithium batteries require highly functional solid state electrolytes. Recent research is primarily focused on crystalline materials, while amorphous materials offer advantages by eliminating problematic grain boundaries that can limit ion transport and trigger dendritic growth at the Li anode. However, simultaneously achieving high conductivity and stability in glasses is a challenge. New quaternary superionic lithium oxythioborate glasses are reported that exhibit high ion conductivity up to 2 mS cm−1 despite relatively high oxygen: sulfur ratios of more than 1:2, that exhibit greatly reduced H2S evolution upon exposure to air compared to Li7P3S11. These monolithic glasses are prepared from vitreous melts without ball‐milling and exhibit no discernable XRD pattern. Solid‐state NMR studies elucidate the structural entities that comprise the local glass structure which dictates fast ion conduction. Stripping/plating onto lithium metal results in very low polarization at a current density of 0.1 mA cm−2 over repeated cycling. Evaluation of the optimal glass composition as an electrolyte in an all‐solid‐state battery shows it exhibits excellent cycling stability and maintains near theoretical capacity for over 130 cycles at room temperature with Coulombic efficiency close to 99.9%, opening up new avenues of exploration for these quaternary compositions.

Effects of preservation methodology on stable isotope compositions of sea stars

Stable isotope analysis is used to investigate the trophic ecology of organisms and, in order to use samples from archived collections, it is important to know whether preservation methods alter the results. This study investigates the long-term effects of four preservation methods on isotopic compositions and isotopic niche parameters of sea stars. We assessed the effects of preservation method (freezing, drying, formaldehyde, ethanol) and duration (0, 1, 3, 6, 9, 12, 24 months) on the stable isotope ratios of carbon, nitrogen and sulfur of sea star tissues. Isotopic ratios were measured using continuous-flow elemental analysis and isotope ratio mass spectrometry. We also monitored the evolution of commonly used ecological metrics (isotopic niche parameters) throughout the experiment. Clear changes in δ13 C values were observed for samples stored in formaldehyde and ethanol. None of the preservation methods had significant or consistent effects on δ15 N values. Formaldehyde preservation induced a decrease in δ34 S values. All these changes could be mitigated using correction factors. Isotopic niche parameters slightly changed over time when computed with δ13 C and δ15 N values, but inconsistent variations occurred when computed with δ13 C and δ34 S values. Overall, these results show that preservation may affect the stable isotope ratios of sea stars. Correction factors can be used to mitigate the effects of the preservation method on stable isotope ratios. Isotopic niche parameters are overall unchanged. Consequently, in most cases, museum samples are suitable for calculation of isotopic niche parameters.

Sulfate nutrition improves short-term Al3+-stress tolerance in roots of Lolium perenne L

Trivalent aluminum ions (Al3+) in acidic soils are a major constraint for crop productivity inhibiting root elongation and promoting cell death. Al3+-toxicity has adverse biochemical and physiological effects on plant root growth. Sulfur is an essential macronutrient assimilated from the soil in the form of sulfate. However, the implication of sulfate nutritional status in the modulation of short-term Al3+-tolerance mechanisms in plant roots has not been previously reported. Here, we evaluated the effects of increased sulfate supply on short-term Al3+-toxicity in roots of Lolium perenne, measuring Al, Ca, Mg and S uptake, lipid peroxidation, total SOD activity, and transcriptional levels of Cu/Zn and Fe-SOD genes. First, the nitrogen sulfur ratio (N/S) in the TF nutrient solutions used in this study were computed to confirm that L. perenne plants were grown in sulfate deficiency (120 μM), optimal supply (240 μM), or overdoses conditions (360 μM), without affecting dry root biomass. Sulfate supplementation (>240 μM, and N/S ratio < 16) played a significant protection to Al3+-stress that prevents morphological changes in root tips, inhibits lipid peroxidation and differentially up-regulates total SOD activity, due changes in SOD gene expression. The results support the importance of sulfate nutritional status, on plant tissue homeostasis, enhancing the physiological tolerance mechanisms modulating lipid peroxidation damage induced by short-term Al3+-toxicity.

Seasonal variations of water-soluble ions in PM10 at a WMO/GAW station in the Yangtze River Delta, China

In order to understand the seasonal levels, formation mechanism and atmospheric chemical behaviours of water-soluble ions of PM10 in the Yangtze River Delta (YRD) region, aerosol samples were collected from January 2nd to December 28th, 2017 at a WMO/GAW regional background station in Lin’an. The concentrations of PM mass and nine water-soluble inorganic ions were obtained. The annual average concentration of PM10 was 59.9±33.9 μg m−3, lower than those reported in previous studies, indicating air quality of YRD region was improved. Nine water-soluble inorganic ions was accounted for 30.2-45.1% of the total PM mass, while ammonium (NH4+), sulfate (SO42+), as well as nitrate (NO3-) were the major ions which contributed 86.3% to total ions. The NO3- concentration was lowest in summer but highest in winter, suggesting it was likely influenced by thermodynamics. The levels of SO42- in spring and winter were related to photochemical reaction and regional transportation. Except for the SNA, Ca2+ was highest in four seasons likely due to sand storm and road fugitive dust. The annual mean ratio of [NO3-]/[SO42-] was nearly to 1, indicating mobile and stationary sources were equally important in Lin’an. The mean nitrogen oxidation ratio (NOR) and sulfur oxidation ratio (SOR) were 0.22±0.13 and 0.41±0.13, respectively, suggesting secondary formation was significant in the atmosphere at the background station of YRD region.

Chemical Characteristics, Spatiotemporal Distribution, and Source Apportionment of PM2.5 Surrounding Industrial Complexes in Southern Kaohsiung

This study investigated PM2.5, specifically, its chemical characteristics and spatiotemporal variation, and identified its potential sources in the Linhai industrial complex of southern Kaohsiung. Seasonal 12-h PM2.5 samples were collected simultaneously at three sampling sites. The results showed that high PM2.5 concentrations mainly occurred during winter and spring, with concentrations at the downwind sites always exceeding those at the upwind sites due to the transport of secondary aerosol by the prevailing winds. 31.4–56.8% of the PM2.5 consisted of water-soluble ions (WSIs), which were dominated by secondary inorganic aerosol (SIA) (SO42– + NO3– + NH4+). High mass ratios between the SIA and the PM2.5 (SIA/PM2.5) were also observed during winter and spring, suggesting that SIA was the primary contributor to the high levels of PM2.5. A neutralization ratio (NR) &lt; 1 indicated that the PM2.5 was acidic, and a nitrogen oxidation ratio (NOR) &gt; 0.1 and a sulfur oxidation ratio (SOR) &gt; 0.25 showed that SIA frequently formed during winter and spring. The metallic elements, which accounted for 12.0–20.2% of the PM2.5, tended to exhibit higher concentrations during daytime than nighttime, and the enrichment factors (EFs) revealed that the trace metals (Ni, Cr, Cu, and Zn) were mainly anthropogenic in origin. Carbonaceous content formed 9.3–24.3% of the PM2.5, and high mass ratios between the organic and the elemental carbon (OC/EC) were also observed during winter and spring. Moreover, the mass ratios between the malonic and the succinic acid (M/S) were always &gt; 1.0 during winter and spring and &lt; 1.0 during summer and fall, demonstrating that organic acids dominated the SOA during the first two seasons. The major sources of PM2.5 in the Linhai industrial complex were steel plants, followed by secondary sulfate and nitrate, vehicular exhaust, petrochemical plants, and incinerators.

Study on the system of calcined desulfurization gypsum - aluminate cement - slag powder cement

In this study, by adding a small amount of calcined desulfurization gypsum and aluminate cement into slag powder cement, the effects of calcined desulfurization gypsum and aluminate cement on the flowability, mechanical properties and volume stability of the composite cementitious system were studied. The results show that the mechanical properties and volume stability of the composite cementitious system can be improved by adding appropriate amount of calcined desulfurization gypsum and aluminate cement. For example, when the ratio of sulfur to aluminum is 0.5:1, the compressive strengths of calcined desulfurization gypsum-aluminate cement-slag powder cement composite cementitious system increases by 34% in 1 day, 8% in 180 days, the free expansion rates are less than 0.6%, and the expansion stresses are less than tensile strengths. The volumes are stable. The hydration products of the system mainly include AFt, Ca(OH)2 and C-S-H. During the hydration process, some of the calcined desulfurization gypsum will be converted into dihydrate desulfurization gypsum.

Infrared light-emitting diodes based on colloidal PbSe/PbS core/shell nanocrystals**Project supported by the National Key Research and Development Program of China (Grant No. 2016YFB0401702), the National Natural Science Foundation of China (Grant Nos. 61674074 and 61405089), Development and Reform Commission of Shenzhen Project, China (Grant No. [2017]1395), Shenzhen Peacock Team Project, China (Grant No. KQTD2016030111203005), Shenzhen Key Laboratory for Advanced Quantum

Colloidal PbSe nanocrystals (NCs) have gained considerable attention due to their efficient carrier multiplication and emissions across near-infrared and short-wavelength infrared spectral ranges. However, the fast degradation of colloidal PbSe NCs in ambient conditions hampers their widespread applications in infrared optoelectronics. It is well-known that the inorganic thick-shell over core improves the stability of NCs. Here, we present the synthesis of PbSe/PbS core/shell NCs showing wide spectral tunability, in which the molar ratio of lead (Pb) and sulfur (S) precursors, and the concentration of sulfur and PbSe NCs in solvent have a significant effect on the efficient PbS shell growth. The infrared light-emitting diodes (IR-LEDs) fabricated with the PbSe/PbS core/shell NCs exhibit an external quantum efficiency (EQE) of 1.3 % at 1280 nm. The ligand exchange to optimize the distance between NCs and chloride treatment are important processes for achieving high performance on PbSe/PbS NC-LEDs. Our results provide evidence for the promising potential of PbSe/PbS NCs over the wide range of infrared optoelectronic applications.