Primary sulfates in atmospheric sulfates: estimation by oxygen isotope ratio measurements

The relative amounts of primary and secondary sulfates in atmospheric aerosols and precipitation can be estimated from measurements of the stable oxygen isotope ratios. The oxygen-18 content of sulfates formed in power plant stack gases before emission into the atmosphere is significantly higher than that of sulfates formed from sulfur dioxide after emission. Results show that 20 to 30 percent of the sulfates in rain and snow at Argonne, Illinois, are of primary origin.     

Laboratory corroboration of the pioneer venus gas chromatograph analyses

Laboratory simulation and tests of the inlet sampling system and columns of the Pioneer Venus gas chromatograph show that the sensitivity to argon is not diminished after the column regeneration step, argon isotopes are not separated, oxygen and sulfur dioxide are not produced in the inlet sampling system from sulfur trioxide, and sulfur trioxide is not formed from sulfur dioxide and oxygen. Comparisons of the volatile inventory of Venus and Earth imply similar efficiencies of early outgassing but a lower efficiency for later outgassing in the case of Venus. The high oxidation state of the Venus atmosphere in the region of cloud formation may prohibit the generation of elemental sulfur particles.     

Sulfur isotope distribution in solfataras, yellowstone national park

Sulfur isotope data on hydrogen sulfide, native sulfur, and sulfates from acid hot-spring areas at Yellowstone National Park suggest that hydrogen sulfide oxidizes to sulfur abiologically, whereas sulfur undergoes biological oxidation to sulfuric acid. An exception occurs at Mammoth Hot Springs where hydrogen sulfide apparently undergoes biochemical oxidation to sulfur.     

葡萄酒中与风味相关4类含硫化合物的研究进展

含硫化合物如谷胱甘肽、硫醇、硫化氢、二氧化硫等都是葡萄酒中重要的风味物质,这4类含硫化合物的含量和形态影响着葡萄酒的风味,且两者都与这4类含硫化合物的来源、检测方法及葡萄酒生产工艺有直接或间接的关系,但针对以上方面的结论仍不统一。基于此,本文整理了这4类含硫化合物在葡萄酒中的含量和存在形态、来源、检测方法、贮藏期间的变化及控制方法这5个方面的研究进展。就含量和存在形态而言,谷胱甘肽主要以还原型谷胱甘肽（GSH）的形式存在,含量不高于70 mg?L ^-1;硫醇以游离态存在,或与金属离子结合,硫醇含量与具体种类相关,数量级从ng?L ^-1到μg?L ^-1不等;硫化氢主要以结合态存在,易与金属离子结合,总含量不高于30 μg?L ^-1;二氧化硫常以气体形式或亚硫酸氢根形式存在,或与含羰基化合物结合,总含量为64.8—166.5 mg?L ^-1。在来源方面,这4类含硫化合物都与发酵期间酿酒酵母的代谢活动有关。谷胱甘肽主要来源于未发酵葡萄汁原料,少部分来源于氨基酸的发酵代谢;硫醇来源于含硫氨基酸、谷胱甘肽的发酵代谢及以硫化氢为底物的化学反应;硫化氢主要源于含硫氨基酸、硫酸盐和亚硫酸盐的发酵代谢;二氧化硫主要来源于外源添加剂,也有少部分源自硫酸盐的发酵代谢。检测这4类含硫化合物时,常采用化学检测方法或光谱法,此类方法检测快速但误差较大;色谱法精确度高,但是样品预处理复杂,仪器昂贵。在贮藏期间葡萄酒中的铁、铜等过渡金属离子和氧气引起的Fenton反应和氧化反应显著影响部分硫醇和硫化氢的含量。最后针对部分含硫化合物带来的异味,可以通过优化原料品质、筛选酿酒酵母菌株、改进二氧化硫添加工艺、添加金属盐等方法降低。在今后的研究中,可从优化检测方法、探究发酵和贮藏陈酿期间含硫化合物变化机理、改进葡萄酒生产环节等方面展开工作。     

Dimethyl sulfide in the surface ocean and the marine atmosphere: a global view

Dimethyl sulfide (DMS) has been identified as the major volatile sulfur compound in 628 samples of surface seawater representing most of the major oceanic ecozones. In at least three respects, its vertical distribution, its local patchiness, and its distribution in oceanic ecozones, the concentration of DMS in the sea exhibits a pattern similar to that of primary production. The global weightedaverage concentration of DMS in surface seawater is 102 nanograms of sulfur (DMS) per liter, corresponding to a global sea-to-air flux of 39 x 10(12) grams of sulfur per year. When the biogenic sulfur contributions from the land surface are added, the biogenic sulfur gas flux is approximately equal to the anthropogenic flux of sulfur dioxide. The DMS concentration in air over the equatorial Pacific varies diurnally between 120 and 200 nanograms of sulfur (DMS) per cubic meter, in agreement with the predictions of photochemical models. The estimated source flux of DMS from the oceans to the marine atmosphere is in agreement with independently obtained estimates of the removal fluxes of DMS and its oxidation products from the atmosphere.     

A mercury-catalyzed, high-yield system for the oxidation of methane to methanol

A homogeneous system for the selective, catalytic oxidation of methane to methanol via methyl bisulfate is reported. The net reaction catalyzed by mercuric ions, Hg(II), is the oxidation of methane by concentrated sulfuric acid to produce methyl bisulfate, water, and sulfur dioxide. The reaction is efficient. At a methane conversion of 50 percent, 85 percent selectivity to methyl bisulfate ( approximately 43 percent yield; the major side product is carbon dioxide) was achieved at a molar productivity of 10(-7) mole per cubic centimeter per second and Hg(II) turnover frequency of 10(-3) per second. Separate hydrolysis of methyl bisulfate and reoxidation of the sulfur dioxide with air provides a potentially practical scheme for the oxidation of methane to methanol with molecular oxygen. The primary steps of the Hg(II)-catalyzed reaction were individually examined and the essential elements of the mechanism were identified. The Hg(II) ion reacts with methane by an electrophilic displacement mechanism to produce an observable species, CH(3)HgOSO(3)H, 1. Under the reaction conditions, 1 readily decomposes to CH(3)OSO(3)H and the reduced mercurous species, Hg(2)(2+) The catalytic cycle is completed by the reoxidation of Hg(2)(2+) with H(2)SO(4) to regenerate Hg(II) and byproducts SO(2) and H(2)O. Thallium(III), palladium(II), and the cations of platinum and gold also oxidize methane to methyl bisulfate in sulfuric acid.     

Is soot composed predominantly of carbon clusters?

Soot generated from diesel fuel in a combustion tube is characterized by microanalysis, x-ray diffraction, chemical reactivity, and nuclear magnetic resonance to address the recent proposal of the significance of carbon clusters in soot. The data support a traditional model of soot as polynuclear aromatic compounds rather than as clusters of carbon atoms with minimal edge site density. The amounts of noncarbon atoms in the soot (hydrogen, oxygen, nitrogen, and sulfur) are commensurate with the edge density of the crystallites (2 by 2 nanometers) inferred from diffraction. The chemistry of soot, in being reduced by potassium metal and alkylated by alkyl iodides, is that known for aromatic compounds and not that anticipated for materials such as graphite, with a small fraction of carbon atoms on edges.     

辽宁省大气环境污染水平与经济发展研究

选取了辽宁省1998～2010年工业废气排放量、工业和生活二氧化硫排放量、工业和生活烟尘排放量、工业粉尘排放量以及辽宁省的GDP结构、人口、能源消耗等环境经济数据,建立经济增长与大气环境污染水平关系的计量模型,即辽宁省环境库兹涅茨曲线( EKC),分析辽宁省近年来经济发展与大气环境污染之间的关系,从宏观上揭示环境库兹涅茨曲线的变化特征及其原因,结果表明,辽宁省环境库兹涅茨曲线特征与工业结构变化、能源消费结构、环境保护投资等有显著相关性.     

Airborne studies of the smoke from the kuwait oil fires

Airborne studies of smoke from the Kuwait oil fires were carried out in the spring of 1991 when approximately 4.6 million barrels of oil were burning per day. Emissions of sulfur dioxide were approximately 57% of that from electric utilities in the United States; emissions of carbon dioxide were approximately 2% of global emissions; emissions of soot were approximately 3400 metric tons per day. The smoke absorbed approximately 75 to 80% of the sun's radiation in regions of the Persian Gulf. However, the smoke probably had insignificant global effects because (i) particle emissions were less than expected, (ii) the smoke was not as black as expected, (iii) the smoke was not carried high in the atmosphere, and (iv) the smoke had a short atmospheric residence time.     

Mass-independent sulfur isotopic compositions in stratospheric volcanic eruptions

The observed mass-independent sulfur isotopic composition (Delta33S) of volcanic sulfate from the Agung (March 1963) and Pinatubo (June 1991) eruptions recorded in the Antarctic snow provides a mechanism for documenting stratospheric events. The sign of Delta33S changes over time from an initial positive component to a negative value. Delta33S is created during photochemical oxidation of sulfur dioxide to sulfuric acid on a monthly time scale, which indicates a fast process. The reproducibility of the results reveals that Delta33S is a reliable tracer to chemically identify atmospheric processes involved during stratospheric volcanism.     

城市环境中毛白杨和油松叶片表面颗粒污染物的观察

本文旨在观察北京地区不同环境中毛白杨和油松叶片表面颗粒污染物状况。选择毛白杨和油松分别代表阔叶乔木和针叶常绿树种。在2014年6、10月分别采集样品,利用环境扫描电镜和X-射线能谱仪对2个采样点2种树种叶表滞留的颗粒物进行了粒径与数量统计及来源解析。结果表明:PM2.5是毛白杨和油松叶表总颗粒物的主要成分,颗粒物主要滞留在毛白杨叶片的上表面和油松针叶的平面;在单位叶面积上,油松叶表面的颗粒物较毛白杨多;西直门样地叶表的PM2.5数量多于奥林匹克森林公园,10月份叶表滞留的颗粒物数量多于6月份。西直门样品除硅铝酸盐颗粒外还包括烟尘集合体和飞灰颗粒,且含有较多的S元素;与奥林匹克森林公园相比,PM2.5污染较重的西直门地区样品气孔较小、密度较大。      

The S3- ion is stable in geological fluids at elevated temperatures and pressures

The chemical speciation of sulfur in geological fluids is a controlling factor in a number of processes on Earth. The two major chemical forms of sulfur in crustal fluids over a wide range of temperature and pressure are believed to be sulfate and sulfide; however, we use in situ Raman spectroscopy to show that the dominant stable form of sulfur in aqueous solution above 250°C and 0.5 gigapascal is the trisulfur ion S(3)(-). The large stability range of S(3)(-) enables efficient transport and concentration of sulfur and gold by geological fluids in deep metamorphic and subduction-zone settings. Furthermore, the formation of S(3)(-) requires a revision of sulfur isotope-fractionation models between sulfides and sulfates in natural fluids.     

Sulfur dioxide contributions to the atmosphere by volcanoes

The first extensive measurements by remote-sensing correlation spectrometry of the sulfur dioxide emitted by volcanic plumes indicate that on the order of 10(3) metric tons of sulfur dioxide gas enter the atmosphere daily from Central American volcanoes. Extrapolation gives a minimum estimate of the annual amount of sulfur dioxide emitted from the world's volcanoes of about 10(7) metric tons.     

Reactions at interfaces as a source of sulfate formation in sea-salt particles

Understanding the formation of sulfate particles in the troposphere is critical because of their health effects and their direct and indirect effects on radiative forcing, and hence on climate. Laboratory studies of the chemical and physical changes in sodium chloride, the major component of sea-salt particles, show that sodium hydroxide is generated upon reaction of deliquesced sodium chloride particles with gas-phase hydroxide. The increase in alkalinity will lead to an increase in the uptake and oxidation of sulfur dioxide to sulfate in sea-salt particles. This chemistry is missing from current models but is consistent with a number of previously unexplained field study observations.     

Nature of the ultraviolet absorber in the venus clouds: inferences based on pioneer venus data

Several photometric measurements of Venus made from the Pioneer Venus orbiter and probes indicate that solar near-ultraviolet radiation is being absorbed throughout much of the main cloud region, but little above the clouds or within the first one or two optical depths. Radiative transfer calculations were carried out to simulate both Pioneer Venus and ground-based data for a number of proposed cloud compositions. This comparison rules out models invoking nitrogen dioxide, meteoritic material, and volatile metals as the source of the ultraviolet absorption. Models involving either small ( approximately 1 micrometer) or large ( approximately 10 micrometers) sulfur particles have some serious difficulties, while ones invoking sulfur dioxide gas appear to be promising.     

蔬菜中二氧化硫残留结果的调查与风险评估

采用蒸馏-滴定法对市场上抽检的六大类共计274件蔬菜样品进行了二氧化硫的检测,以了解样品中二氧化硫的残留量,并在此基础上评估了各类蔬菜对人体的健康风险。结果表明,检测样品中二氧化硫残留量最高的是银耳(801 mg/kg),其次是黄花菜(280mg/kg),最小的是马铃薯(5 mg/kg);二氧化硫残留对人体健康有一定的风险,风险较大的是银耳和黄花菜,其风险商值HQ均大于1,其余的品种HQ均小于1,没有食用风险。     

Sighting of el chichon sulfur dioxide clouds with the nimbus 7 total ozone mapping spectrometer

The eruptions of El Chichón volcano on 28 March and 3 and 4 April 1982 were observed by the Nimbus 7 total ozone mapping spectrometer due to strong absorption by volcanic gases at the shortest wavelengths of the spectrometer (312.5 and 317.5 nanometers). These ultraviolet pictures permit a measurement of the volume, dispersion, and drift of volcanic gas clouds. The tropospheric clouds were rapidly dispersed in westerly winds while persistent stratospheric clouds drifted in easterly winds at speeds up to 13 meters per second. The spectral reflectance is consistent with sulfur dioxide absorption and rules out carbon disulfide as a major constituent. A preliminary estimate of the mass of sulfur dioxide deposited in the stratosphere by the large eruptions on 3 and 4 April is 3.3 x 10(6) tons. Prior estimates of volcanic cloud volume were based on extrapolation of locally measured sulfur dioxide concentrations.     

比色法快速测定党参中二氧化硫的残留量

[目的]测定党参中二氧化硫的残留量。[方法]采用比色法快速测定党参中二氧化硫的残留量。[结果]在0.0～48.0μg/ml范围内,二氧化硫浓度与吸光度的线性关系良好,相关系数R为0.999 2,相对标准偏差在0.54%～1.66%;加标回收率为90.1%～103.7%,RSD为1.16%～5.17%(n=6),且具有良好的重现性和稳定性。应用测试结果表明,比色法的测定结果与酸蒸馏法相似。[结论]该方法简便、快速、灵敏度高、干扰少,可用于党参中二氧化硫的残留量测定。     

Bacterial Methanogenesis and Growth from CO2 with Elemental Iron as the Sole Source of Electrons

Previous studies of anaerobic biocorrosion have suggested that microbial sulfur and phosphorus products as well as cathodic hydrogen consumption may accelerate anaerobic metal oxidation. Methanogenic bacteria, which normally use molecular hydrogen (H(2)) and carbon dioxide (CO(2)) to produce methane (CH(4)) and which are major inhabitants of most anaerobic ecosystems, use either pure elemental iron (Fe(0)) or iron in mild steel as a source of electrons in the reduction of CO(2) to CH(4). These bacteria use Fe(0) oxidation for energy generation and growth. The mechanism of Fe(0) oxidation is cathodic depolarization, in which electrons from Fe(0) and H(+) from water produce H(2), which is then released for use by the methanogens; thermodynamic calculations show that significant Fe(0) oxidation will not occur in the absence of H(2) consumption by the methanogens. The data suggest that methanogens can be significant contributors to the corrosion of iron-containing materials in anaerobic environments.     

Large sulfur isotope fractionation does not require disproportionation

The composition of sulfur isotopes in sedimentary sulfides and sulfates traces the sulfur cycle throughout Earth's history. In particular, depletions of sulfur-34 ((34)S) in sulfide relative to sulfate exceeding 47 per mil (‰) often serve as a proxy for the disproportionation of intermediate sulfur species in addition to sulfate reduction. Here, we demonstrate that a pure, actively growing culture of a marine sulfate-reducing bacterium can deplete (34)S by up to 66‰ during sulfate reduction alone and in the absence of an extracellular oxidative sulfur cycle. Therefore, similar magnitudes of sulfur isotope fractionation in sedimentary rocks do not unambiguously record the presence of other sulfur-based metabolisms or the stepwise oxygenation of Earth's surface environment during the Proterozoic.