冷蒸气发生-原子荧光光谱法测定化工废水中的无机汞和总有机汞

用氢化物发生－原子荧光光谱法测定了化工废水中的无机汞和总有机汞。无机汞可以直接测定;用过硫酸钾在沸水浴中加热20min即可把有机汞转化为无机汞,实现总汞的测定,二者之差为总有机汞。对影响测定灵敏度的一些实验参数进行了优化,汞的检测限为8．2ng/L。     

煤气化渣脱除燃煤烟气中汞的性能研究

汞作为一种重金属污染物,对环境和人体健康影响很大,如何对其高效脱除已引起了研究者的广泛关注。本研究使用煤气化渣及其分选后样品作为脱汞吸附剂,通过固定床和气流床脱汞实验考察了吸附剂的脱汞性能,利用N_2吸附-脱附、X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电镜(SEM)等表征手段分析了吸附剂的物化特性。固定床脱汞评价结果显示,OS和HCS在60-120℃保持91%以上的脱汞效率;HAS在60℃有最高97%的脱汞效率,HAS的脱汞活性受脱汞温度影响较大。Hg-TPD和XPS表征结果表明,吸附剂中的化学吸附氧参与了汞的氧化,在吸附剂表面生成HgO。气流床脱汞评价结果表明,OS和HCS在碳汞比为40000,脱汞温度为60℃时,脱汞效率分别为56%、57%;当碳汞比为80000,脱汞温度为60℃时,脱汞效率分别为100%、82%。     

洗选过程对宁武煤中汞迁移和热释放的影响特性

采用逐级化学提取和热分析方法,选取宁武煤田某洗煤厂原煤及洗选产物为研究对象,在汞质量平衡基础上对煤中汞赋存形态进行分类并验证,进而考察了洗选过程对煤中汞迁移行为和热释放的影响特性。结果表明,洗选过程在降低原煤灰分和硫分含量的同时也改变了汞的富集规律,引起了汞的重新分配;样品中汞元素与灰分和硫含量之间的线性相关性分别为0.89和0.99,原煤中汞主要以无机结合态存在,其迁移行为受控于无机矿物质迁移,洗选后矸石总汞绝对含量较原煤增加了322.8%,而精煤汞含量降低至原煤的40%,汞脱除率达到56.4%;洗煤产物中汞富集程度的差异与其在原煤中赋存形态密切相关,其中,矸石中硫化物结合态汞的占比高达56.6%,而精煤和煤泥中有机结合态汞较原煤中均有所提高;相同温度下汞在煤泥中释放率最大,矸石中最小,所有样品中汞至650℃均接近完全析出;煤中汞热释放特性也与其赋存形态密切相关,不同热解温度段汞热释放行为由煤中汞的固有赋存形态所决定,其中,有机结合态汞随有机质分解在300℃已大量逸出,而硫化物结合态汞分解温度主要为400-600℃。     

新试剂1-(2-苯并噻唑)-3-(3,5-二溴吡啶)-三氮烯与汞的荧光猝灭反应及其应用

<正>自20世纪50年代日本熊本县水俣市发生了震惊世界的汞中毒事件以来,汞对环境和人体健康的危害已引起极大关注。研究表明,金属汞中毒常以汞蒸气的形式引起,由于汞蒸气具有高度的扩散性和较大的脂溶性,通过呼吸道进入肺泡,经血液循环运至全身。血液中的金属汞进入脑组织后,被氧化成汞离子,逐渐在脑组织中积累,达到一定的量,就会对脑组织造成损害。另外一部分汞离子转移到肾脏。无机汞化合物可通过肠道吸收,汞(Ⅱ)较     

环境汞污染

由于特殊的物理化学性质和强的毒性,汞已经成为全球关注的污染物.本文对目前大气汞的来源、汞在大气中的形态分布及在全球大气分布的特点和汞在大气中的迁移转化规律等方面进行了详细地介绍,提出了大气汞研究的展望.评述了近年来水生生态系统汞的生物地球化学循环研究领域的新进展及存在问题,提出了对汞甲基化机理认识的研究要进一步加强的观点.对汞矿开采和混汞法炼金区环境汞污染及对居民健康的危害研究进展进行了详细地评述,指出矿区居民汞暴露的主要途径.最后,本文还总结了目前人体暴露不同形态汞对人体健康影响的最新进展.     

电石法生产聚氯乙烯过程中汞的流向及处理技术分析

汞是对环境有高度敏感性的重金属,汞污染已经成为全球高度关注的敏感议题。我国汞资源相对匮乏,对汞资源的过度消耗和汞污染是电石法生产聚氯乙烯(PVC)行业发展的巨大障碍。本文针对电石法生产PVC中的严重汞污染问题,分析了生产过程中汞的来源、流向,并且提出对应的处理技术,为电石法生产PVC中的汞污染防治提供思路。     

静止汞电极的伏安法

伏安法(voltammetry)这个名称由柯尔蜀夫(Kolthoff)和莱提南(Laitinen)提出。该名称的原意为测量的是电压和电流,至今伏安法其实已成为许多电化学方法的总名称了。在伏安法中所使用的电极有固体电极和液体的汞电极等。液体汞电极的装置有运动的和静止的二类。运动的有滴汞、泉汞、流汞、旋转汞滴、振动汞电极等;静止的有汞杯、掛汞滴、鍍汞滴、悬汞滴、臥汞滴以及早在1943年就被应用于极譜法中的汞池电极等。     

荧光光度法测定大气、水和土壤中痕量汞

本文研究了汞离子与硫化荧光素汞反应定量地释放出荧光素汞的条件,提出了一种间接测定痕量汞的荧光光度法。应用于大气、水和土壤中痕量汞的测定,方法简便、快速。     

如何预防汞中毒

工厂是造成汞污染的主要源泉。因此 ,在生产中如何减少或消除汞的污染是化学工作者的首要任务。汞易蒸发 ,为防止汞的蒸发 ,可在汞的表面上倒一层水。如果温度计等被打破或滴落少量汞 ,应即立撒上硫磺粉 ,使汞变成硫化汞 ,并把碎玻璃清除。制汞或使用汞的工厂中 ,应定期用碘熏蒸 ,生成碘化汞以消除汞患。红汞不宜与碘酒一起擦同一患处。两者相遇会发生化学反应析出汞。鱼是餐桌上鲜美的菜肴 ,但值得人们警惕的是 ,鱼类对汞有很强的浓缩作用 ,如金鱼在每升含 0 0 0 0 3毫克的甲基汞溶液中 ,驯养 3 8天 ,鱼体的甲基汞浓度是溶液的 50 0倍。据…     

循环流化床燃煤锅炉中的汞迁移研究

采用美国环保署颁布的吸附剂吸附汞采样方法30B(USEPA 40 CFR Part 60 30B)采集燃煤烟气中汞。选择一循环流化床燃煤机组进行现场采样,吸附剂吸附烟囱处烟气中的汞、入炉煤样、锅炉底灰、静电除尘器飞灰等样品同时采集。对该机组中汞质量平衡率进行衡算,通过汞质量平衡率说明了汞采样方法的准确性和有效性。评价了汞在飞灰、底灰和烟气中的分布,循环流化床锅炉底灰中对脱汞的贡献率仅0.55%,飞灰脱除汞的效率高达83.37%,剩余的16.08%的汞排放入大气环境,表明循环流化床机组是有效控制汞的清洁煤燃烧技术。     

Mercury speciation by CE: a review

CE methods for the speciation of inorganic and organomercury compounds are reviewed. Sample preparation, separation conditions and detection modes are discussed. Efficient separation and sensitive determination of mercury species by CE typically involves complexation with various thiols, chromogenic and other chelating agents; however, some methods do not require complexation. Spectrophotometric detection based on UV-visible absorption is by far the most commonly used. Hyphenated techniques, such as CE/inductively coupled plasma (ICP)-MS, hydride generation coupled to ICP-MS or atomic fluorescence spectrometry and CE/atomic absorption spectrometry are gaining popularity due to their high sensitivity and selectivity. Last, but not least, the potential and applications of electrochemical methods for detection of separated mercury species are outlined.     

天然水中痕量无机汞和有机汞的氢化物原子荧光光谱法分析

建立了天然水中溶解的痕量无机汞和有机汞的氢化物原子荧光光谱法分析方法,该方法经标准物质(PACS-1)和加标回收实验研究表明重现性好、准确度高。在此基础上,应用该方法分析了该校人工湖水中的无机汞和有机汞,发现无机汞和有机汞的含量均低于0.1 礸/L。     

土壤样品中汞的形态分析研究进展

土壤中汞的活性及其生物有效性因其赋存形态不同而存在差异,汞赋存形态分析已成为环境科学领域研究的热点之一。归纳总结了近年来土壤环境中汞赋存形态分类、样品预处理技术和汞形态分析技术研究进展,指出了未来的发展方向。     

Speciation analysis for mercury in gas condensates by capillary gas chromatography with inductively coupled plasma mass spectrometric detection

A method allowing species-selective determination of atomic mercury, non-polar dialkylated mercury compounds,polar monoalkylated species and inorganic mercury complexes in natural gas condensates was developed. Inductively coupled plasma mass spectrometry was employed as a detection method for capillary gas chromatography and compared with microwave induced plasma atomic emission detection for the analysis of hydrocarbon-rich matrices. The method was based on two consecutive injections allowing comprehensive speciation analysis. First a sample aliquot was diluted with toluene and analysed for Hg0 and individual dialkylmercury compounds. Then, another aliquot was butylated with a Grignard reagent for the species specific determination of Hg(II) and monoalkylated mercury species. The detection limits were down to 0.08 pg level.     

Detoxification of mercury species—an in vitro study with antidotes in human whole blood

To investigate the effects of mercury species intoxication and to test the efficiency of different commonly applied antidotes, human whole blood and plasma surrogate samples were spiked with inorganic mercury (Hg²⁺) and methylmercury (MeHg⁺, CH₃Hg⁺) prior to treatment with the antidotes 2,3-dimercaptopropan-1-ol (British Anti Lewisite), 2,3-dimercaptosuccinic acid (DMSA), and N-acetylcysteine (NAC). For mercury speciation analysis in these samples, liquid chromatography was coupled to either inductively coupled plasma mass spectrometry (ICP-MS) or electrospray ionisation time-of-flight mass spectrometry (ESI-TOF-MS). Adduct formation between mercury species and physiological thiols (cysteine and glutathione) was observed as well as the release of glutathione under treatment with the antidotes DMSA and NAC.     

Inorganic and methylmercury speciation in environmental samples

The different strategies for mercury species analysis in environmentally-related samples are reviewed. After consideration of the main different steps involved in the speciation of mercury, such steps are discussed with more extension for mercuric ion and methylmercury. The different approaches for preservation of these mercury species during the storage of samples are considered. Different ways for the extraction of mercury species from the several possible environmental compartments and the possibilities for preconcentration of such species after previous derivatization reactions are discussed. Mercuric ions and methylmercury chromatographic and non-chromatographic separations along with different techniques used for sensitive and selective detection of mercury are also critically reviewed. Ranges of published detection limits achievable for such species determination, by using hyphenated techniques between a chromatographic separation and a specific atomic detector are also given.     

Capillary electrophoresis-inductively coupled plasma-mass spectrometry: an attractive complementary technique for elemental speciation analysis

Some basic and practical aspects of interfacing capillary electrophoresis to inductively coupled plasma-mass spectrometry (CE-ICP-MS) are reviewed in this article with emphasis on the use of this hyphenated technique for elemental speciation analysis. The principles behind the techniques of both CE and ICP-MS are introduced. The interfacing of CE to ICP-MS is discussed including several devices and nebulizers reported in literature. A brief account of their advantages and limitations is given. The various CE-ICP-MS applications for elemental speciation analysis are also reviewed. Some issues concerning the future of CE-ICP-MS for the elemental speciation analyses are discussed.     

UV irradiation controlled cold vapor generation using SnCl2 as reductant for mercury speciation.

A simple and ultrasensitive method, which was based on cold vapor generation (CVG) coupled to atomic fluorescence spectrometry (AFS), was proposed for speciation analysis of inorganic mercury (Hg2+) and methylmercury (MeHg) in water samples. In the presence of UV irradiation, all the mercury (MeHg+Hg2+) in a sample solution can be reduced to Hg0 by SnCl2; without UV irradiation, only Hg2+ species can be determined. So the concentration of MeHg can be obtained from the difference of the total mercury and Hg2+ concentration; thus, speciation analysis of Hg2+ and MeHg was simply achieved without chromatographic separation. Under the optimized experimental conditions, the limits of detection were 0.01 ng mL-1 for both Hg2+ and MeHg. The sensitivity and limit of detection were not dependent on the mercury species, and a simple Hg2+ aqueous standard series can be used for the determination of both Hg2+ and MeHg.     

天然水体中痕量汞的形态分析方法研究

天然水体中汞的含量仅为ng/L级，不仅难以测出，而且在测定过程中极易受到干扰；利用两次金汞齐的预富集方法与原子荧光法结合的技术，作者建立了天然水体超痕量不同形态汞的准确分析方法；该方法的检出限达到了0．02ng／L，实验平均回收率为101%；该方法也适用于其它低汞含量水样(包括稀释后的污水及化工废水)中汞的形态分析。     

Evaluation of various sample pre-treatment methods for total and inorganic mercury determination in biological certified reference materials by CVAAS technique

Sample preparation methods for non-separation cold vapor atomic absorption spectrometry (CVAAS) sequential inorganic mercury speciation in biological certified reference materials (CRMs) were investigated. The methylmercury concentration was calculated as the difference between total and inorganic mercury. Microwave-assisted decomposition method, and three ultrasonic extraction procedures based on acid leaching with HCl and HCOOH and solubilization with TMAH were employed as sample preparation methods. The replacement of a sample decomposition procedure by extraction prior to analysis by CVAAS, as well as the aspect of speciation analysis is discussed. The limits of detection in the sample were determined as 50 and 10 ng L⁻¹ for inorganic and total mercury, which corresponds to absolute detection limits of 40 and 8 ng g⁻¹ for inorganic and total mercury, respectively. The results were in good agreement with the 95% confidence level t-test of the certified values for total and inorganic mercury in the reference materials investigated. From the analysis of the CRMs, it was evident that the difference between the total and inorganic mercury concentrations agrees with the methylmercury concentration. The relative standard deviation was better than 11% for most of the samples.