弱碱性阴离子树脂分离富集-发射光谱法测定痕量钯

在盐酸介质中，钯与氯离子发生反应生成配合物[PdCl6]^2-，该配合物能被大孔弱碱性苯乙烯系阴离子交换树脂吸附。吸附物灰化后，灰分与缓冲剂混合均匀，全部装入杯形电极，发射光谱法测定钯。方法检出限为0．12ng／g（10．0g样品）。方法经国家一级标准物质验证，测定值与标准值相符，精密度（RSD，n=12）为8．9％～13．9％，回收率为89％～118％。方法已用于测定水系沉积物中的痕量钯。     

环境样品中钼的测定方法进展

根据多年来国内对钼的测定方法的研究报道,对环境样品中钼的主要测定方法进行总结,常用方法有分光光度法、催化极谱法、原子吸收分光光度法、ICP—AES法及ICP-MS等,分析了它们的优缺点,有利于选择适宜的测定方法。     

阴离子交换树脂-活性炭动态吸附无火焰原子吸收法测定矿石中的微量金铂钯

采用717阴离子交换树脂-活性炭分离富集矿石中的微量Au、Pt、Pd。40μg待测元素富集结果表明,Au、Pt、Pd的回收率分别为100%、95.3%和96.3%。以HC l为介质在无火焰原子吸收仪上测定。方法经对国家一级标准物质GBW 07291、GBW 07292分析检验,结果与标准值相符。对GBW 07291国家一级标准物质测定7次,其精密度(RSD)分别为:Au 9.4%、Pt 11.2%、Pd 3.0%。方法适用于矿石中10-6~10-9量级Au、Pt、Pd的测定。     

Gold in natural water: A method of determination by solvent extraction and electrothermal atomization

A method has been developed using electrothermal atomization to effectively determine the amount of gold in natural water within the nanogram range. The method has four basic steps: (1) evaporating a 1-L sample; (2) putting it in hydrobromic acid-bromine solution; (3) extracting the sample with methyl-isobutyl-ketone; and (4) determining the amount of gold using an atomic absorption spectrophotometer. The limit of detection is 0.001 μg gold per liter. Results from three studies indicate, respectively, that the method is precise, effective, and free of interference. Specifically, a precision study indicates that the method has a relative standard deviation of 16–18%; a recovery study indicates that the method recovers gold at an average of 93%; and an interference study indicates that the interference effects are eliminated with solvent extraction and background correction techniques. Application of the method to water samples collected from 41 sites throughout the Western United States and Alaska shows a gold concentration range of < 0.001 to 0.036 μg gold per liter, with an average of 0.005 μg/L.     

The determination of chlorine in rocks and minerals by pyrohydrolytic method

In this paper a porcedute of pyrohydrolysis spectrophotometric determination has been established for chlorine in rocks and minerals. The selection of accelerator and its required quantity, the time and temperature of sample decomposition and the influence of interferring elements and other factors are also discussed in detail. Because samples are usually fused with alkalis, higher blank is an insurmountable problem. However, with our procedure, the above-mentioned drawback can be effectively overcome, and the determination of trace chlorine either in large or in minor quantities of samples also is rather ideal. The determined results indicate that the relative standard deviations are 8.7% in the former and 4.5% in the latter case. This procedure is simple, rapid and well reproduceable. The detection limit of the method is 10 ppm. The results obtained by our procedure are in good agreement with the proposed values from two reference samples in China (DZΣ-1 and DZΣ-2) and one international geochemical reference sample (RGM-1). This method has proved itself to be reliable.     

伽马能谱法测量水中226Ra最短平衡时间的确定

伽马(γ)能谱法测量水中226Ra,在制样过程中天然放射性核素衰变链遭到破坏,一般规定样品放射性平衡期为3～4周后测定。通过试验证明,样品天然放射性核素衰变链最终达到平衡的最短时间为11d,测量结果在允许误差范围内,满足测量精度。     

水资源(环境)承载力的研究进展

概述了水资源(环境)承载力的概念、特征、量化评价方法及其总体研究的进展。强调了系统研究水资源(环境)承载力的重要现实意义。指出了当前研究中的不足,以及有待进一步研究的问题。     

PNN测井清污混注水淹层剩余油饱和度计算方法

过套管脉冲中子—中子(PNN)测井技术通过测量未被地层俘获的热中子数量来识别流体性质,解决了水淹层电性测井响应不明显以及中子寿命测井受伽马本底影响的问题.本文引入自适应遗传算法,通过选择、交叉、变异概率的设定以及在标准层中选取初始种群的方法,有效消除了多种非地质因素的影响,得到解释参数最优解;针对研究区块清污混注导致混合地层水矿化度变化大的特点,提出变参数PNN解释方法,分小层计算混合地层水宏观俘获截面,达到准确识别水淹层、大幅度提高剩余油饱和度计算精度的效果.     

生态及环境需水量研究进展与前瞻

论述了国内外有关生态、环境需水研究的进展情况,包括研究内容、定量计算方法及其研究成果等。在此基础上,指出目前生态、环境需水研究领域存在的主要问题,从理论和实践两个方面,提出了生态、环境需水今后需进一步研究的课题。     

The determination of cassiterite tin in soils and sediments by an atomic absorption-volatile hydride method

Cassiterite tin is determined after sample decomposition with ammonium iodide. The sublimate, collected in a separate condenser, is dissolved in tartaric acid solution and the tin is reduced to tin hydride in a continuous flow system by means of sodium tetrahydroborate. Atomisation is effected in a shielded hydrogen-argon diffusion flame to provide a high sensitivity determination. Interferences are negligible and the precision (12% R.S.D.) and detection limit (0.2 μ/g^-1) obtained, as well as the throughput (60 samples per hour), are suitable for geochemical exploration.     

Uranium determination in natural water by the fissiontrack technique

The fission track technique, utilizing the neutron-induced fission of uranium-235, provides a versatile analytical method for the routine analysis of uranium in liquid samples of natural water. A detector is immersed in the sample and both are irradiated. The fission track density observed in the detector is directly proportional to the uranium concentration. The specific advantages of this technique are: (1) only a small quantity of sample, typically 0.1–1 ml, is needed; (2) no sample concentration is necessary; (3) it is capable of providing analyses with a lower reporting limit of 1 μg per liter; and (4) the actual time spent on an analysis can be only a few minutes. This paper discusses and describes the method.     

Separation of Platinum from Palladium and Iridium in Iron Meteorites and Accurate High‐Precision Determination of Platinum Isotopes by Multi‐Collector ICP‐MS

This study presents a new measurement procedure for the isolation of Pt from iron meteorite samples. The method also allows for the separation of Pd from the same sample aliquot. The separation entails a two‐stage anion‐exchange procedure. In the first stage, Pt and Pd are separated from each other and from major matrix constituents including Fe and Ni. In the second stage, Ir is reduced with ascorbic acid and eluted from the column before Pt collection. Platinum yields for the total procedure were typically 50–70%. After purification, high‐precision Pt isotope determinations were performed by multi‐collector ICP‐MS. The precision of the new method was assessed using the IIAB iron meteorite North Chile. Replicate analyses of multiple digestions of this material yielded an intermediate precision for the measurement results of 0.73 for ε¹⁹²Pt, 0.15 for ε¹⁹⁴Pt and 0.09 for ε¹⁹⁶Pt (2 standard deviations). The NIST SRM 3140 Pt solution reference material was passed through the measurement procedure and yielded an isotopic composition that is identical to the unprocessed Pt reference material. This indicates that the new technique is unbiased within the limit of the estimated uncertainties. Data for three iron meteorites support that Pt isotope variations in these samples are due to exposure to galactic cosmic rays in space.     

碱熔重铬酸钾滴定岩石中全铁的不确定度评定

通过碱熔重铬酸钾滴定岩石中全铁的分析,找出了影响滴定结果的各个分量。影响滴定结果的分量有:配制重铬酸钾标准溶液的浓度、称取试样的质量、滴定过程中所消耗重铬酸钾标准溶液的体积以及铁的摩尔质量等。在此基础上对不确定度的分量进行了评定与合成,给出了扩展不确定度,并按照计量技术规范,结出了相应的表示形式。     

水环境质量综合评价的多目标决策-理想区间法

对水环境质量综合评价中应用的多目标决策-理想点法进行了分析,认为实际上水环境质量评价标准是区间概念而非点的概念,因而传统的多目标决策-理想点法把评价标准处理成理想点存在一定缺陷。为了克服这种缺陷,提出了一种多目标决策-理想区间法(MODMIIM)。介绍了MODMIIM的原理,给出了它的构成方法,并把它应用到水环境质量综合评价中。MODMIIM与PP模型和神经网络法相比,简单、有效;与多目标决策理想点法相比,具有更大的适用性。MODMIIM可广泛应用于各种环境质量综合评价中。     

鲁南山区基岩蓄水构造类型及找水定井方法

以鲁南地区地下水为研究对象,通过分析其赋存特征及影响因素,总结地下水蓄水构造类型及特征,提出找水定井示范方法,评价及开发利用地下水资源。研究显示,受地质构造、地层岩性、地形地貌、裂隙岩溶发育程度及裂隙充填情况等影响,不同地区地下水赋存特征也不相同,鲁南地区蓄水构造主要包括岩溶蓄水构造和裂隙蓄水构造两大类,针对不同地层岩性找水定井方法也不相同。建议相关部门采取措施改变鲁南山区的缺水现状。     

深埋隧道外水压力计算的解析-数值法

在高水头富水区,抗水压衬砌设计的关键在于外水压力的计算。深埋隧道排水时,沿轴线方向上流入隧道的水量来自于隧道掌子面的前方,当隧道施工足够长度后,可以认为已施工断面的地下水只从隧道两侧向断面内运动,此时可将三维问题处理为二维。对于深埋隧道,当其断面远小于水头时,可处理为一个点井;隧道全断面排水时,隧道断面线可处理为定流量边界。首先建立隧道排水的水文地质概念模型,采用经验解析法预测隧道的涌水量,然后将涌水量代入隧道围岩渗流的剖面二维模型,模拟隧道排水时围岩渗流场的分布,再采用作用系数的方法计算出隧道衬砌的外水压力。     

长春市水环境系统的仿真模拟

区域水环境的主要问题是水环境容量,且对其计算涉及到整个区域的经济、社会以及环境的综合因子,并关系到整个区域是否能实现可持续发展。采用系统动力学模型,运用DYNAMO语言对长春市水环境容量进行仿真模拟,通过调控参数提出多种替代方案。在调控科技投资、公众节水意识以及水价等政策参数的基础上,结合长春市的实际情况,提出了合理利用长春市水环境容量的理想方案,为长春市实现可持续发展提供必要的科学依据。     

Paleostress determination in a rock by a fractographic method

A fractographic technique, hitherto used in ceramics for the evaluation of fracture stress, is adapted here to calculate fracture paleostresses in rocks. An example from a granite in East Sinai is analyzed. The results obtained for the ranges of local paleofracture stress, the severest flaw size and the initial stress intensity factor agree reasonably well with previous evaluations of fracture stresses in granite and with direct observations of the rock's grain size.     

A novel label-free method for determination of inorganic mercury in environmental aqueous media using BSA-modified silver nanoparticles

A selective colorimetric sensor was developed for rapid and fast determination of highly toxic Hg²⁺ according to decolorization of unmodified silver nanoparticles (AgNPs). A simple strategy was used for providing water-soluble AgNPs. Bovine serum albumin (BSA) and sodium borohydride were used as stabilizing and reducing agents, respectively. AgNPs, prepared by BSA, were stable for 2 months. The freshly prepared bio-stabilized AgNPs were brownish yellow in color owing to the severe surface plasmon resonance (SPR) peak at 420 nm. The yellow AgNPs solution became colorless in the presence of Hg²⁺, as well as a gradual blue shift, and decrease in the intensity of absorption peak was observed with increasing the concentrations of mercury, because of aggregation of the nanoparticles. The calibration curve was linear from 5 to 80 µM (r = 0.994). The detection limit was 2.7 µM. Selective determination of mercury (II) ions was performed in the presence of other ions. To investigate the practical applications of BSA/AgNPs in real samples, mercury determination was performed in a groundwater sample and good recoveries (>94.0 %) were obtained.     

环境同位素在水循环研究中的应用

环境同位素广泛存在于自然界水体中,在降水、地表水、地下水、土壤水和植物体内相互转化的水循环过程中,同位素的分馏效应导致不同水体具有不同的同位素含量。利用不同水体同位素含量之间的差异,可研究它们之间的相互转化方式及转化量。介绍了环境同位素在大气降水和降水-地表水-地下水“三水”之间转化中的研究进展,并阐述了其在水循环应用中存在的问题及应用前景。