AGAGE Observations of Methyl Bromide and Methyl Chloride at Mace Head, Ireland, and Cape Grim, Tasmania, 1998–2001     

P. G. Simmonds  R. G. Derwent  A. J. Manning  P. J. Fraser  P. B. Krummel  S. O'Doherty  R. G. Prinn  D. M. Cunnold  B. R. Miller  H. J. Wang  D. B. Ryall  L. W. Porter  R. F. Weiss  P. K. Salameh 《Journal of Atmospheric Chemistry》2004,47(3):243-269

In situ AGAGE GC-MS measurements of methyl bromide (CH₃Br) and methyl chloride (CH₃Cl) at Mace Head, Ireland and Cape Grim, Tasmania (1998–2001) reveal a complex pattern of sources. At Mace Head both gases have well-defined seasonal cycles with similar average annual decreases of 3.0% yr⁻¹ (CH₃Br) and 2.6% yr⁻¹ (CH₃Cl), and mean northern hemisphere baseline mole fractions of 10.37 ± 0.05 ppt and 535.7 ± 2.2 ppt, respectively. We have used a Lagrangian dispersion model and local meteorological data to segregate the Mace Head observations into different source regions, and interpret the results in terms of the known sources and sinks of these two key halocarbons. At Cape Grim CH₃Br and CH₃Cl also show annual decreases in their baseline mixing ratios of 2.5% yr⁻¹ and 1.5% yr⁻¹, respectively. Mean baseline mole fractions were 7.94 ± 0.03 ppt (CH₃Br) and 541.3 ± 1.1 ppt (CH₃Cl). Although CH₃Cl has astrong seasonal cycle there is no well-defined seasonal cycle in the Cape Grim CH₃Br record. The fact that both gases are steadily decreasing in the atmosphere at both locations implies that a change has occurred which is affecting a common, major source of both gases (possibly biomass burning) and/or their major sink process (destruction by hydroxyl radical).  相似文献   

苏北盆地部分古生界原油来自第三系源岩的证据     

陈安定 《江苏地质》2005,29(4):193-197

苏北盆地LT1井、D7井、7．43井和L1井等古生界原油的地球化学特征研究表明，它们来自古新统阜宁组源岩。“新生石储”现象主要是新生界源岩与古生界储层呈断层接触造成的。  相似文献   

Kinetic investigation of the OH + CH3Br reaction between 248 and 390 K     

A. Chichinin  S. Teton  G. Le Bras  G. Poulet 《Journal of Atmospheric Chemistry》1994,18(3):239-245

The rate parameters for the reaction of the OH radical with CH₃Br have been measured using the discharge flow-electron paramagnetic resonance method. The result isk ₁=(1.86±0.48)×10^–12 exp[–(1230±150)/T] cm³ molecule^–1 s^–1. This value is compared to earlier data and is found to be in excellent agreement with the most recent results, which greatly increases the accuracy of the ozone depletion potential of CH₃Br which can be derived from these kinetic data.  相似文献   

The contribution of old and new water to a storm hydrograph determined by tracer addition to a whole catchment     

R. Collins  A. Jenkins  M. Harrow 《水文研究》2000,14(4):701-711

Two tracer experiments have been carried out at an enclosed catchment in southern Norway. The catchment was brought to steady state with respect to rainfall and runoff prior to the tracer addition. A known concentration of lithium bromide was then added to the rainfall for the duration of each event. The tight control on tracer concentration and rainfall amount enabled assessment of the contribution of old and new water to runoff, the dominant flow pathways and soil water residence times during a storm event. A significant volume of ‘old’ water contributes to runoff despite the hydrologically responsive nature of the catchment and several hours of tracer injected rainfall are required before ‘new’ water becomes the dominant runoff source. After 34 h of tracer injection, ‘new’ water apparently contributes c. 83% to instantaneous flow and c. 55% of the total tracer input to the catchment has been lost in runoff. Recovery of the tracer from soil water indicates that the organic soil surface layer is the dominant flow pathway for rainwater through the catchment and that a significant pathway also exists at the soil–bedrock interface. New water is retained in deep pockets of soil for several days. Assessment of the conservative behaviour of the tracer suggests that 10–14% of the input Br⁻ is retained in the soil and the tracer is not conservative. Laboratory experiments indicate that sorption of Br⁻ to organic soil is the likely mechanism of retention. This process is probably concentration dependent and will have occurred predominantly during the initial period of tracer application. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

Removal of dyes from aqueous solutions using low-cost sorbents made of solid residues from olive-mill wastes (JEFT) and solid residues from refined Jordanian oil shale     

W. Y. Abu-El-Sha'r  S. H. Gharaibeh  S. Mahmoud 《Environmental Geology》2000,39(10):1090-1094

The effectiveness of processed solid residue from olive-mill waste (JEFT) and solid residue of pyrolyzed oil shale in removing methylene blue as a cationic dye and methyl orange as an anionic dye from aqueous solutions has been investigated and compared with that of a commercial activated carbon, namely coconut-shell carbon. All three sorbents showed significant methylene-blue removal, but only the coconut granular-activated carbon showed notable methyl-orange removal. The oil-shale sorbent showed no removal and the olive carbon showed poor removal of methyl orange. The removal of both methylene blue and methyl orange increases with the lapse of time, and attains equilibrium in 100 min. Received: 12 May 1999 · Accepted: 1 November 1999  相似文献   

溴化锂的生产工艺综述          下载免费PDF全文

魏述彬  邓小川 《盐湖研究》2006,14(3):58-62

综述了国内外溴化锂生产方法,并指出了每种方法的优缺点,同时展望了今后溴化锂生产方法的发展方向。  相似文献   

The relationships between particulate and soluble alkaline phosphatase activities and the concentration of phosphorus dissolved in the seawater of Toulon Bay (NW Mediterranean)     

Gérard Bogé  Magali Lespilette  Dominique Jamet  Jean-Louis Jamet 《Marine pollution bulletin》2013

The activities of particulate and soluble phosphatase were analyzed monthly for 1 year in the coastal ecosystems of the NW Mediterranean Sea. The mean contribution of the particulate activity increased from 56% at an MUF-P concentration of 30 μM to 77% at 0.04 μM. This particulate activity was negatively correlated with the DIP, DOP and TDP concentrations when the activities were related to the seawater volume, chlorophyll a or the protein concentration. The TDP correlations were highly significant (p: 0.001). The DOP correlations were significant (p: 0.04) and became highly significant (p: 0.009) at low DIP concentrations (<0.13 μM). The DIP correlations were significant (p: 0.04) only at low DOP concentrations (<0.18 μM). Thus, the effects of seawater DIP and DOP were found to be linked. The soluble activity exhibited distinct phosphatase fractions with high (0.5–29.5 μM) and low (0.02–2 μM) Km values, but none exhibited significant correlations with phosphorus compounds.  相似文献   

钼－氨三乙酸－溴邻苯三酚红－溴化十六烷基三甲基铵体系的显色反应及其应用     

罗宗铭  钟卓荣 《岩矿测试》1994,(3)

在ｐＨ２．５的氯乙酸缓冲介质中，有溴化十六烷基三甲基铵（ＣＴＭＡＢ）存在下，Ｍｏ（Ⅵ）与氨三乙酸（ＮＴＡ）及溴邻苯三酚红（ＢＰＲ）形成胶束混配配合物，该配合物最大吸收波长在６００ｎｍ，摩尔吸光系数为７．２７×１０￣４Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１），配合物组成为Ｍｏ（Ⅵ）：ＮＴＡ：ＢＰＲ：ＣＴＭＡＢ＝１：１：２：４。Ｍｏ（Ⅵ）量在０～１．０ｇ／ｍｌ范围内符合比尔定律。由于ＮＴＡ的存在，改善了方法的选择性，可直接分光光度测定矿石及钢中微量Ｍｏ。  相似文献   

相转移催化合成增塑剂邻苯二甲酸丁苄酯的研究     

曹小红刘瑛  刘云海 《华东地质学院学报》2005,28(2):166-168

以CTMAB为相转移催化剂，苯酐、正丁醇和苄氨为原料合成BBP的新方法。通过设计正交实验，对原料配比、反应时间、催化荆用量、pH值和加水量等影响因素以及催化荆的回收利用进行了研究。实验结果表明，苯酐：正丁醇：CT．MAB：苄氨为1：1．33：0．04：1．2，pH值为9，反应时间为3h，反应过程中的加水量为1％时最高酯产率可达到80％以上。本方法操作简单，耗时少，成本低，催化荆可回收利用，产品质量好，无“三废”污染，并易于工业化生产。  相似文献   

Speciation of Polysulfides and Zerovalent Sulfur in Sulfide-rich Water Wells in Southern and Central Israel     

A. KamyshnyJr.  M. Zilberbrand  I. Ekeltchik  T. Voitsekovski  J. Gun  O. Lev 《Aquatic Geochemistry》2008,14(2):171-192

Zerovalent sulfur and inorganic polysulfides were determined in nine sulfide-rich water wells in central and southern Israel. Although the two locations belong to the same aquifer, they are characterized by different pH and hydrogen sulfide levels. Hydrogen sulfide in the central Israel wells ranged between 19 and 32 μM, and the pH was 7.26 ± 0.07. The southern basin is characterized by lower water circulation, lower pH (around 6.8), and higher hydrogen sulfide levels (>470 μM). Polysulfides were determined by a rapid single-phase methylation using methyl trifluoromethanesulfonate (methyl triflate) reagent. The summary polysulfide concentration for S₄²⁻–S₇²⁻ species was found to be around 0.14–0.75 μM in the central region of Israel and substantially higher, 2.3–4.6 μM in the southern region. The sum of polysulfide zerovalent sulfur and colloidal sulfur was quantitatively detected by cyanide derivatization and compared to polysulfide sulfur determined by methyl triflate derivatization and to the chloroform extraction of zerovalent sulfur. A method for the determination of sulfur undersaturation level—the ratio between dissolved elemental sulfur and its equilibrium concentration in the presence of solid sulfur—based on the observed levels of the major polysulfide species is described. The observed polysulfide speciation was compared with the predicted speciation under sulfur saturation conditions taking into account the water temperature, its ionic strength, and pH. Criteria for sulfur saturation versus unsaturated conditions were established based on (1) the chain length dependence of the ratio between the observed polysulfide concentrations and their predicted value under sulfur saturated conditions, and (2) the difference between the concentration of zerovalent sulfur, as determined by cyanolysis, and the total polysulfide sulfur. According to this dual criterion five of the water wells were classified as being undersaturated with respect to sulfur, though for all the examined water wells the majority of the zerovalent sulfur was in the form of polysulfide sulfur.  相似文献