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抓有两个稳定同位素35Cl和37Cl，在自然界中的丰度分别为24.23％和75.77%。自然界中氯同位素的组成变化很小，氯同位素组成的表示方法一般用δ37C1值表示：37C1=[(37Cl/35C1)sample-1 (37Cl/35C1)Std]×1000 δ37C1在自然界的变化范围约为15‰(-8.0‰~+7.5‰)。由于海水中的氯同位素组成非常均一，Kaufman等（1984)调查发现世界大洋海水中氯同位素组成相同，因此建议采用标准海水（SMOC）作为氯同位素标准。氯同位素的分析方法主要包括气体同位素质谱法和热电离质谱法，目前的分析精度可达0.2‰。 对于大部分同位素而言，由扩散引起的同位素分馏主要与化学和生物过程有关。研究表明沉积物间隙水中造成氯同位素分馏的原因主要3个：①矿物在海水中沉淀的过程中优先富集37C1(Magenheim等，1994,1995);②扩散过程,35C1的扩散速度高于37C1(Desaulnier等，1986;Eggenkomip等，1994);③沉积物的离子隔膜过滤作用，当流体通过粘土矿物时，由于沉积物表层负电荷的排斥,35Cl受到的排斥作用大于37Cl，因此流体中会富集37C1，此机制被Campbell(1985）通过实验得到了证实。 氯是上地壳流体中主要的阴离子，在矿物岩石和矿床的形成过程中起着重要的作用，因此研究自然界中抓的分布和运移对于地球科学各个研究领域而言有着重要的意义。目前已对大气圈、水圈和岩石圈的氯同位素组成进行过分析，大气气溶液中δ37C1的变化范围为+0.42‰-2.53‰；河水中的δ37C1较高为+0.74‰-+2.85‰,盐湖卤水δ37C1则相对较低，为-2.06‰~+1.01‰，地下水中δ37C1变化范围较小为-0.50‰~+0.69‰；俯冲间隙水氯同位素组成最低，变化范围为-7.5‰~-2.2‰；新鲜的洋中脊玄武岩（ MORB）玻璃体中δ37C1的变化范围为+3.0‰~+7.2‰，去气地幔中δ37C1值为+4.7%；而富集地幔中δ37C1落在0.4‰~3.4‰之间；麻粒岩δ37C1的变化范围很小，其中大部分的岩石和矿物δ37C1都集中在-0.3‰~+0.11‰之间，平均值为-0.15‰，而角闪石和黑云母δ37C1分别为-1.12‰和+0.79‰;岩盐中δ37C1的变化范围为-0.6‰~+1.2‰。 氯同位素地球化学的研究工作在总体上仍处于起步阶段，但该方法在地球科学各个领域已经显示了极好的应用前景。氯同位素组成可以用于示踪板块俯冲和壳幔物质循环过程、热液成矿过程中成矿流体的起源和演化以及盐湖和岩石中卤水的起源和演化。 相似文献
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氯离子质量平衡法(CMB)利用惰性示踪剂Cl-可以揭示区域地下水平均补给速率,补给事件和环境、气候变化事件等信息,可为相关研究提供可靠的信息。虽然该方法简单、有效,已经得到大量应用,但是也具有明显的局限性。综述了基于CMB法的相关研究,回溯了该方法的提出和演化,讨论了其主要假设条件和应用的局限性,阐明为了准确地应用该方法需要加强的方面。首先要重视氯离子干沉降的观测和研究。其次要加强氯离子沉降空间变化的观测和研究。在方法上要注意综合采用多种示踪剂、土壤理化性质和平行钻孔等手段来研究。最后要加强对氯离子平衡过程,及其相关的自然过程和人类活动的研究。对促进氯离子质量平衡法在地下水研究方面的应用和发展,具有一定的参考价值。 相似文献
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探讨氯化锌活化黄姜皂素纤维渣的机理, 应用TG-FTIR联用技术考察了黄姜皂素纤维渣的氯化锌热解特性.不同的配比、氛围及升温速率对热解均有影响.低温氧化有利于活性炭的形成, 但高温氧气的存在对炭体烧失较大; 氯化锌与原料的配比越高, 对原料的侵蚀性越强, 采取相应的活化温度较低; 升温速率越低越有利于原料中有机质蓄积热量热解, 相应的活化温度也越低; 红外光谱图也表示挥发分产物的出现与热重分析相符, 没有时间滞后现象.因此, 确定制备活性炭的初步工艺为先在300℃左右低温炭化, 再在保护气氛中(如N2) 500℃左右活化, 升温速率10K/min左右.工业生产条件下, 活化温度最高不宜超过650℃. 相似文献
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《中国地球化学学报》2006,25(B08):255-256
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氯离子守恒法确定土壤生态蓄水量 总被引：1，自引：0，他引：1
通过实验测得降水及土壤水的氯离子浓度,依据化学守恒原理,即降水与包气带土壤水中氯离子的质量守恒关系,计算出长春市丘陵、台地、阶地3类不同地貌区土壤一年内所得水量,该水量为土壤生态蓄水量。将土壤生态蓄水量与土壤的田间持水量、作物的生态需水量进行对比分析,评述了三者之间的关系。阐明土壤生态蓄水量不仅能客观反映土壤中的水分含量情况,也能对植被生态需水量的满足情况给予客观评价。 相似文献
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Zhoushan City in Zhejiang Province is the focus of China’s reclamation area, and it also has a great influence on the groundwater quality. Based on the observed data of groundwater level and chloride ion concentration, groundwater quality in the next 6 years in Zhoushan area is predicted and analyzed by using groundwater numerical simulation software GMS. According to the comparison of observed groundwater level and simulated groundwater level at the end time, it is found that the whole water level in the filling area has the small fluctuation, which is within the range of 1 m. And the highest concentration of chloride ion is in the eastern coastal area. The prediction results indicate that there is no obvious trend of sea water with high chloride ion concentration to land. Under the condition of the current groundwater utilization, the groundwater level in Donggang sea area of Zhoushan is stable, and the chloride ion concentration has a slight decrease trend. 相似文献
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矿石中微量钪的测定,由于没有高选择性和高灵敏度的方法,分析手续繁杂冗长。特别当试样含有大量钍、铀,锆(铪)、钛和稀土元素时,更增加分析的困难。钪与铬天青S和氯化十四烷基二甲基苄基胺于微酸性介质中形成的三元络合物,具有很高的灵 相似文献
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离子色谱法同时测定天然碱矿中氯离子和硫酸根离子 总被引：1，自引：1，他引：0
通过测定氯离子和硫酸根离子可以确定天然碱矿中石盐和芒硝的含量,目前分析方法比较少,且流程冗长,容易污染,生产效率低。本文建立了离子色谱-抑制电导法测定天然碱矿中氯离子和硫酸根的分析方法。样品中水溶性阴离子经热水溶解进入溶液,以30 mmol/L氢氧化钾溶液作为淋洗液,利用AG19阴离子保护柱、AS19阴离子分离柱分离样品中的氯和硫酸根,CRD 200碳酸盐消除装置去除了碳酸根的干扰。方法检出限氯离子为0.01 mg/L,硫酸根为0.02 mg/L;加标回收率为100.9%～104.1%;精密度(RSD,n=10)小于2.5%。实际样品分析结果与滴定法的测定值基本吻合。本法操作简单,重现性好,灵敏度高,结果可靠,不受样品复杂组分及形成缓冲溶液体系的干扰,很好地解决了传统方法费时、耗材、不能同时测定氯离子和硫酸根的问题。 相似文献
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使用可循环的NH4Cl 溶液作为中间媒介获取Mg2+用于CO2 矿物封存是一种新兴工艺,但是纤蛇纹石在NH4Cl 溶液中较
低的Mg2+浸出率却是这项工艺发展的瓶颈。针对这一问题,本文采用灼烧处理对纤蛇纹石进行改性。结果表明, 灼烧处理
可以有效改变纤蛇纹石中Mg2+反应活性。在600℃灼烧后,所得产物与NH4Cl 反应的转化率达到55.64%,比灼烧前提高了
约43%。600℃灼烧处理脱除了纤蛇纹石外羟基,增大了矿物的反应表面积和具反应活性的Mg2+的量,促进了其与NH4Cl 的
反应 ;脱除内羟基后,具反应活性Mg2+减少,与NH4Cl 反应的转化率降低。 相似文献
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预富集柱—离子色谱法测定高纯水中痕量氟和氯 总被引：3，自引：0，他引：3
在国产离子色谱仪上加装填充有季铵型阴离子交换剂的预富集柱，所设计的流路和方法可将测定Ｆ－和Ｃｌ－的检出限分别降至０１７μｇ／Ｌ和０２７μｇ／Ｌ。测定精密度好，ＲＳＤ＜５％，方法满足反应堆堆芯冷却水中痕量Ｆ－和Ｃｌ－的检测要求。 相似文献
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Lead chloride formation constants at 25°C were derived from analysis of previous spectrophotometrically generated observations
of lead speciation in a variety of aqueous solutions (HClO4–HCl and NaCl–NaClO4 mixtures, and solutions of MgCl2 and CaCl2). Specific interaction theory analysis of these formation constants produced coherent estimates of (a) PbCl+,
\textPbCl20 {\text{PbCl}}_{2}^{0} , and PbCl3− formation constants at zero ionic strength, and (b) well-defined depictions of the dependence of these formation constants
on ionic strength. Accompanying examination of a recent IUPAC critical assessment of lead formation constants, in conjunction
with the spectrophotometrically generated formation constants presented in this study, revealed significant differences among
various subsets of the IUPAC critically selected data. It was found that these differences could be substantially reduced
through reanalysis of the formation constant data of one of the subsets. The resulting revised lead chloride formation constants
are in good agreement with the formation constants derived from the earlier spectrophotometrically generated data. Combining
these data sets provides an improved characterization of lead chloride complexation over a wide range of ionic strengths:
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log \text Cl b 1 = 1. 4 9 1- 2.0 4 I 1/ 2 ( 1+ 1. 5 I 1/ 2 ) - 1 + 0. 2 3 8 I log \text Cl b 2 = 2.0 6 2- 3.0 6 I 1/ 2 ( 1+ 1. 5 I 1/ 2 ) - 1 + 0. 3 6 9 I log \text Cl b 3 = 1. 8 9 9- 3.0 6 I 1/ 2 ( 1+ 1. 5 I 1/ 2 ) - 1 + 0. 4 3 9 I. \begin{gathered} {\log}\,{}_{\text{ Cl}} \beta_{ 1} = 1. 4 9 1- 2.0 4\,I^{ 1/ 2} \left( { 1+ 1. 5\,I^{ 1/ 2} } \right)^{ - 1} +\,0. 2 3 8\,I \hfill \\ {\log}\,{}_{\text{ Cl}} \beta_{ 2} = 2.0 6 2- 3.0 6\,I^{ 1/ 2} \left( { 1+ 1. 5\,I^{ 1/ 2} } \right)^{ - 1} +\,0. 3 6 9\,I \hfill \\ {\log}\,{}_{\text{ Cl}} \beta_{ 3} = 1. 8 9 9- 3.0 6\,I^{ 1/ 2} \left( { 1+ 1. 5\,I^{ 1/ 2} } \right)^{ - 1} +\,0. 4 3 9\,I. \hfill \\ \end{gathered} 相似文献
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基体分离-电位滴定法测定高硫金属矿中的微量氯 总被引：2，自引：1，他引：1
使用碳酸钠-氧化锌混合碱焙烧样品,将硫化物矿中的低价硫转化为硫酸盐或高价硫,过滤分离基体,采用电位滴定法测定硫化物矿(铜精矿、锌精矿、硫铁矿)中的微量氯,消除由于硫化银沉淀的产生对氯化银测定结果的干扰。通过电位突越,确定滴定终点,消除色度和浊度对滴定终点的影响。采用电极电位-浓度二次微商滴定曲线,计算滴定终点。对混合碱的选择及加入量、焙烧温度、溶液酸度、测定温度、滴定介质以及基体和共存元素的干扰进行了试验。方法精密度(RSD,n=9)均小于9%,回收率为94.1%~105.6%。 相似文献
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Sudhakar M. Rao T. Thyagaraj P. Raghuveer Rao 《Geotechnical and Geological Engineering》2013,31(4):1399-1404
Compacted expansive clays swell due to crystalline swelling and osmotic/double layer swelling mechanisms. Crystalline swelling is driven by adsorption of water molecules at clay particle surfaces that occurs at inter-layer separations of 10–22 Å. Diffuse double layer swelling occurs at inter-layer separations >22 Å. The tendency of compacted clay to develop osmotic or double layer swelling reduces with increase in solute concentration in bulk solution. This study examines the consequence of increase in solute concentration in bulk solution on the relative magnitudes of the two swelling modes. The objective is achieved by inundating compacted expansive clay specimens with distilled water and sodium chloride solutions in free-swell oedometer tests and comparing the experimental swell with predictions from Van’t Hoff equation. The results of the study indicate that swell potential of compacted expansive clay specimens wetted with relatively saline (0.4, 1 and 4 M sodium chloride) solutions are satisfied by crystalline swelling alone. Comparatively, compacted clay specimens inundated with less saline solutions (0.005–0.1 M sodium chloride) require both crystalline and osmotic swelling to satiate the swell potential. 相似文献
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Natural feldspathoidal syenites may be approximated by assemblagescontaining some or all of the phases sodalite, nepheline, oneor two alkali feldspars, and aqueous chloride fluid in the systemNaAISi3O8-KAISi3O8-NaAISiO4-KAISiO4-NaCI-KCI-H2O. The stabilityof sodalite in these assemblages was studied in the range 500–700°C and 600–2000 bars fluid pressure. Sodalite appears to be a stable phase on the vapor-saturatedliquidus in this system over a wide range of pressure. At or near the vapor-saturated liquidus minimum in this system,three distinct types of sodalite-bearing syenite can crystallize.Nepheline-sodalite-one alkali feldspar rocks, nepheline-sodalite-twoalkali feldspars rocks and sodalite-analcime-bearing rocks crystallizebelow 1600 bars, between 1600 and 2750 bars and above 2750 barsfluid pressure, respectively. The effects of closed-system cooling on the assemblage sodalite-nepheline-twoalkali feldspars-aqueous fluid are different and distinguishablefrom the effects of metasomatism. Closed-system cooling resultsin replacement of K-feldspar by albite, feldspathoids remainingnearly unchanged, while metasomatism generally results in sismultaneousenrichment or impoverishment in sodalite plus K-feldspar. 相似文献
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复方化学消毒剂中苯扎氯铵的高效液相色谱测定 总被引：1，自引：0，他引：1
建立了一种测定复方化学消毒剂中苯扎氯铵成分十二烷基二甲基苄基氯化铵、十四烷基二甲基苄基氯化铵和十六烷基二甲基苄基氯化铵的反相离子对高效液相色谱法。色谱柱为Platisil ODS(5μm,250 mm×4.6mm),流动相为甲醇-0.2 mol/L己烷磺酸钠(含1%三乙胺,V/V,用高氯酸调节至pH=6.0,体积比85∶15),紫外220 nm检测。用己烷磺酸钠作为离子对试剂,增强了苯扎氯铵成分的保留,三乙胺作为扫尾剂,通过抑制固定相表面残存的硅羟基对苯扎氯铵成分的吸附,减少了色谱峰拖尾。3种苯扎氯铵成分分离良好,标准曲线的线性范围分别为0.002～5 mg/mL、0.005～10 mg/mL和0.005～10 mg/mL,检测限分别为0.0005 mg/mL、0.001mg/mL和0.001 mg/mL。方法具有良好的准确度和精密度,在测定低浓度样品时优势明显。实际用于测定苯扎氯铵消毒液和医用消毒纸巾中3种苯扎氯铵成分的含量,回收率为99.3%～104.1%,日内和日间测定相对标准偏差(RSD)均小于2.0%。 相似文献
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在调查掌握某化工厂区地下水氯化物指标的基础上,得出了该化工厂区地下水中氯化物为污染指标。查明了该化工厂区水文地质条件,建立了该区水文地质概念模型,采用模型计算方法,预测了该化工厂区地下水流场的变化,对工厂企业采取治理措施后的地下水中氯化物浓度进行了分析与预测,对治理措施的有效性进行了评价。结果表明:模型计算结果能够反映该区地下水中氯化物的变化规律,在工厂企业采取污染防治措施之后,该区内地下水中氯化物浓度大幅下降,计算结果与实际监测结果相符,模型可预测该化工厂区地下水氯化物发展趋势,对该化工厂区地下水污染防治具有重要的实际意义。 相似文献
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The results presented in this paper shows that high concentrations of sodium hydroxide causes abnormal changes on the volume
change behaviour of illite–smectite (interstratified mineral) soil due to mineralogical changes. The higher swell that occurs
is shown in the form of a new second stage of swelling. Increase in negative charges on soil particles and mineralogical changes
after interaction with soil, respectively, are responsible for the swelling in these two stages. However, potassium hydroxide
does not induce such high swelling in soils. This is mainly due to the fixation of potassium ions. Hence an attempt has been
made to control the swelling induced by sodium hydroxide by making used of potassium chloride as an additive. Potassium fixation
which is not substantial at neutral pH is favoured at higher pH Addition of potassium chloride salt solution (as 2 and 5%
solution) can reduce only the first stage of swelling by linking the unit layers of mineral by reducing development diffuse
double layer near clay surface. Potassium chloride is unable to prevent the formation of mineralogical alteration due to soil
alkali interaction and hence the swelling associated with mineralogical changes. X-ray diffraction studies have revealed that
mineralogical changes leading to formation of zeolite by soil alkali interaction is not inhibited by potassium ions. Morphological
changes studied by scanning electron microscope corroborate these observations. Also the compressibility of soil which is
increased in alkali solution is reduced in the presence of potassium salts. This reduction is due to reduction in the first
stage of swelling. 相似文献
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