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1.
Determination of Free Cd,Cu and Zn Concentrations in Lake Waters by In Situ Diffusion Followed by Column Equilibration Ion-exchange 总被引:1,自引:0,他引:1
Combining in situ diffusion and column ion-exchange equilibration, we measured free metal ion concentrations (Cd, Cu and Zn)
in water samples collected from the epilimnion of 14 lakes in the Rouyn-Noranda area (600 km north-west of Montreal, QC, Canada).
Lakes were selected to represent a wide range of physico-chemical characteristics (hardness, pH, dissolved organic matter—DOM,
degree of metal contamination), to determine the influence of these parameters on metal speciation. Total dissolved metal
concentrations, as determined within the diffusion cells, varied over one to two orders of magnitude: [Cd] 0.19–2.9 nM; [Cu]
36–190 nM; [Zn] 7–2,800 nM. The proportion of total dissolved metal present as free Cd2+ and Zn2+ was relatively constant for the 14 selected lakes, despite the wide pH (4.5–8) and DOM (3–23 mg C/L) ranges, probably reflecting
the inverse relationship observed between pH and DOM; this proportion did, however, vary with DOM and pH for Cu. Our experimental
free metal ion concentrations were compared with those calculated with the thermodynamic models WHAM (Windermere Humic Aqueous
Model VI) and ECOSAT 4.7 (incorporating the NICA-Donnan model). Measured and calculated values were in reasonable agreement
for both Cd and Zn although measured values were generally slightly higher, i.e. less than one order of magnitude. For several
lakes, measured free Cu concentrations were, however, much higher than the calculated values, suggesting that these models
overestimate Cu complexation. The gap between measured and calculated free metal ion concentration becomes more important
as the total metal concentration decreases and as pH increases. 相似文献
2.
奥地利安东帕有限公司 《岩矿测试》2009,28(3):306-306
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10 μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提出了具体测定要求。 相似文献
3.
Water samples from eight major Texas rivers were collected at different times during 1997–1998 to determine the dissolved and particulate trace metal concentrations, expected to show differences in climate patterns, river discharge and other hydrochemical conditions, and human activities along the different rivers. Specifically, two eastern Texas rivers (Sabine, Neches) lie in a region with high vegetation, flat topography, and high rainfall rates, while four Central Texas rivers (Trinity, Brazos, Colorado, and San Antonio) flow through large population centers. Relatively high dissolved organic carbon (DOC) concentrations in the eastern Texas rivers and lower pH led to higher Fe and Mn concentrations in river waters. The rivers that flow through large population centers showed elevated trace metal (e.g., Cd, Pb, Zn) concentrations partly due to anthropogenically produced organic ligands such as ethylenediaminetetraacetic acid (EDTA) present in these rivers. Trace metal levels were reduced below dams/reservoirs along several Texas rivers. Statistical analysis revealed four major factors (suspended particulate matter [SPM], EDTA, pH, and DOC) that can explain most of the observed variability of trace metal concentrations in these rivers. SPM concentrations directly controlled particulate metal contents. Variation in pH correlated with changes of dissolved Co, Fe, Mn, and Ni, and particulate Mn concentrations, while DOC concentrations were significantly related to dissolved Fe concentrations. Most importantly, it was found that, more than pH, EDTA concentrations exerted a major control on dissolved concentrations of Cd and Zn, and, to a lesser extent, Cu, Ni, and Pb. 相似文献
4.
手持式X射线荧光光谱仪测定富钴结壳样品中锰铁钴镍铜锌 总被引:1,自引:3,他引:1
便携式X射线荧光光谱仪可以快速进行多元素实时分析,在富钴结壳资源勘查中有广阔的应用前景,但是现有仪器的分辨率和稳定性有待进一步提高,特别是现场原位分析法的应用有待研究。本文针对富钴结壳中目标元素含量相对较高的特点,采用松散粉末法制样,建立了手持式X射线荧光光谱仪快速测定太平洋富钴结壳样品中Mn、Fe、Co、Ni、Cu和Zn的分析方法。该方法用多金属结核和富钴结壳国家标准物质进行验证,测定值的相对标准偏差(RSD)在0.2%~3.0%之间,测定值与标准值的相对误差为92.9%~107.6%。样品现场分析和实验室分析的数据对比表明,除了低含量Cu略有超差外,Mn、Fe、Co、Ni、Zn和品位均无超差,完全满足该类矿产资源勘查规程的要求。本法简单、高效,适用于对野外富钴结壳资源作出快速的初步评价。 相似文献
5.
The cation distribution of Co, Ni, and Zn between the M1 and M2 sites of a synthetic olivine was determined with a single-crystal
diffraction method. The crystal data are (Co0.377Ni0.396Zn0.227)2SiO4, M
r
= 212.692, orthorhombic, Pbnm, a = 475.64(3), b = 1022.83(8), and c = 596.96(6) pm, V = 0.2904(1) nm3, Z = 4, D
x
= 4.864 g cm−3, and F(0 0 0) = 408.62. Lattice, positional, and thermal parameters were determined with MoKα radiation; R = 0.025 for 1487 symmetry-independent reflections with F > 4σ(F). The site occupancies of Co, Ni, and Zn were determined with synchrotron radiation employing the anomalous dispersion effect
of Co and Ni. The synchrotron radiation data include two sets of intensity data collected at 161.57 and 149.81 pm, which are
about 1 pm longer than Co and Ni absorption edges, respectively. The R value was 0.022 for Co K edge data with 174 independent reflections, and 0.034 for Ni K edge data with 169 reflections. The occupancies are 0.334Co + 0.539Ni + 0.127Zn in the M1 sites, and 0.420Co + 0.253Ni + 0.327Zn
in the M2 sites. The compilation of the cation distributions in olivines shows that the distributions depend on ionic radii
and electronegativities of constituent cations, and that the partition coefficient can be estimated from the equation: ln [(A/B)M1/(A/B)M2] = −0.272 (IR
A
-IR
B
) + 3.65 (EN
A
−EN
B
), where IR (pm) and EN are ionic radius and electronegativity, respectively.
Received: 8 April 1999 / Revised, accepted: 7 September 1999 相似文献
6.
7.
计算极谱法同时测定镉镍的研究 总被引:1,自引:0,他引:1
采用普通极谱仪与计算机联机技术,用卡尔曼滤波处理以KSCN为支持电解质的Cd~(2+)和Ni~(2+)混合溶液的示波极谱重叠波。实验表明,极谱可逆波具有较好的加和性,可采用计算极谱方法对多组分(尤其是难以分开的重叠波)进行同时测定。 相似文献
8.
M. Khosravi M. Taghi Ganji R. Rakhshaee 《International Journal of Environmental Science and Technology》2005,2(1):35-40
The limitation of plant growth in the polluted mediums can be used as a factor to determine of plant tolerance and the toxic effect of these mediums. In this work, the effect of Pb2+, Cd2+, Ni2+and Znsu2+ (individually) on Azolla filiculoides growth in the aqueous solution and using this method to water post treatment were studied. During 15 days the biomass the fresh Azolla with initial mass of 20 g was grown on the nutrient solution containing these metal ions, each in a concentration 4 mg/l. The presence of these ions, caused about 25%, 42%, 31% and 17% inhibition of biomass growth, respectively, in comparison to Azolla control weight which had not heavy metals. The water salinity of 1, 2 and 4 g. NaCl/l decreased the removal of these heavy metals about 4–7%, 20–24% and 40–55%, respectively. The addition of total dissolved solids (TDS) from 50 to 300 ppm. (as CaCO3) into the samples of containing heavy metals increased Azolla growth, but decreased the control Azolla growth. 相似文献
9.
Geochemistry of Cu, Co, Ni, Zn, Cd and Cr in the surficial sediments of a tropical estuary, southwest coast of India: a granulometric approach 总被引:3,自引:0,他引:3
Geochemical characteristics of six trace metals – Cu, Co, Ni, Zn, Cd and Cr – in the bulk sediment and sand, silt and clay
fractions of a tropical estuary on the southwest coast of India have been studied and discussed. In bulk sediment, the trace
metal concentration is controlled mainly by the textural composition of the sample. Mud, sandy mud and sandy silt register
higher concentrations of trace metals than that in sand-dominant sediments. The granulometric partitioning studies also re-affirmed
the role of particle size in enriching the trace metals. The silt and clay fractions exhibit 7–8 times the enrichment of Cu
and Cd compared to that in sand. The enrichment factors of Zn, Cr, Ni and Co in the silt and clay fractions, compared to that
in sand, are 5–6, 4–5, 2–5 and 2–3 times, respectively. The trace metals in the sand fraction, particularly Ni and Cr, exhibit
strong positive correlation with the heavy mineral content of the samples. It clearly indicates a heavy mineral pathway to
the trace metals in the sand fraction. Cu and Co in silt and clay fractions exhibit a marked decrease towards the high saline
zones of the estuary. This is attributed to the desorption of Cu and Co from particulate phases during estuarine mixing. Contrary
to Cu and Co, the content of Zn in the clay fraction shows a marginal increase towards the estuarine mouth. This could be
explained by the influx of Zn-rich contaminant discharges from Zn-smelting industries located slightly north of the estuarine
mouth. The released Zn will effectively be held in the lattices of the clay mineral montmorillonite, which also exhibits a
marked increase towards the estuarine mouth. The anomalously high values of Cd in some places of the Central Vembanad estuary
is attributed to the local pollution.
Received: 10 July 1995 · Accepted: 3 June 1996 相似文献
10.
Errors in atomic absorption spectrophotometric determinations of Pb, Zn, Ni and Co may occur due to the presence of Fe, Al, Ca, Mg, Na and K in the sample solution. At low concentrations of trace element in solution (i.e., up to about 1 p.p.m.) and low concentrations of major elements (up to about 4,000 p.p.m. total cations), the main source of interference is enhancement due to background absorption; this may be corrected by the hydrogen continuum or by use of a non-absorbing wavelength. At higher concentrations of trace element the enhancement due to molecular absorption is partly or completely nullified through suppression caused by major element interference. Similarly, at higher concentrations of major elements, suppression occurs which is probably a function of atomizer efficiency. In these situations, correction for total molecular absorption results in a residual negative error.The errors in determination of Pb, Zn, Ni and Co in geological materials are often ignored in exploration geochemistry work. This restriction on the accuracy of the analytical data is becoming more important with the increasing use of exploration methods based on rock analyses. The errors may be minimized by ensuring that the concentration of both trace element and major element in solution is too low to cause significant suppression effects. Under these circumstances, reasonable results should be obtained through correction for background absorption. 相似文献
11.
微量单矿物方铅矿和闪锌矿中主体元素和痕量元素的多项分析,作者根据金属元素在阴离子交换树脂上与在盐酸、氢溴酸、硝酸、硫酸溶液之间的行为差别,试验了用阴离子交换色谱分离的条件,选用不同浓度的盐酸溶液洗提铜、钴、镍、锰、铅和银;氢溴酸溶液洗提锌;硝酸溶液洗提镉;最后用硫酸溶液洗提铋。本文所拟定的分析流程简便,试用于微量单矿物方铅矿和闪锌矿中九个元素的测定,效果较好。 实验部分 一、主要试剂 相似文献
12.
Yamini Gopalapillai Ismail I. Fasfous John D. Murimboh Tahir Yapici Parthasarathi Chakraborty Chuni L. Chakrabarti 《Aquatic Geochemistry》2008,14(2):99-116
Free metal ion concentration is generally considered a useful indicator of a metal’s bioavailability and ecotoxicity to aquatic
biota. This article reports the speciation of nickel in mining and municipal effluents from Sudbury (Ontario, Canada), and
also in model solutions containing a fully characterized laurentian fulvic acid (LFA) at environmentally relevant concentrations.
A column ion exchange technique (IET) using a cation exchange resin (Dowex 50W-X8) was applied to determine free nickel ion
concentrations. In model solutions, reasonable correlation was found between the predictions of an equilibrium-based computer
speciation code, Windermere Humic Aqueous Model (WHAM) VI, and the results obtained by IET at low nickel-to-fulvic acid ratios.
However at higher mole ratios, the WHAM VI predicted higher free nickel ion concentrations than IET. Only three out of six
effluent samples showed reasonable agreement between the IET and the WHAM VI results, indicating the need for further development
of IET for application to effluent waters. 相似文献
13.
Potential Orthopyroxene,Clinopyroxene and Olivine Reference Materials for In Situ Lithium Isotope Determination 总被引:1,自引:0,他引:1 下载免费PDF全文
Ben‐Xun Su Xiao‐Yan Gu Etienne Deloule Hong‐Fu Zhang Qiu‐Li Li Xian‐Hua Li Nathalie Vigier Yan‐Jie Tang Guo‐Qiang Tang Yu Liu Kwan‐Nang Pang Aaron Brewer Qian Mao Yu‐Guang Ma 《Geostandards and Geoanalytical Research》2015,39(3):357-369
Over 1400 electron probe and 700 ion probe microanalyses were performed on eleven mineral separates to evaluate their potential as reference materials for in situ Li isotopic determination. Our results suggest the homogenous distributions of major elements, Li and its isotopes for each sample. Hence, these samples are suitable to be used as reference materials for in situ measurements of Li abundance and Li isotopes by secondary ion mass spectrometry (SIMS) or laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS). These samples have the advantage of mitigating probable matrix effects during calibration owing to the wide range of compositions. The effect of composition on the δ7Li of olivine measured by SIMS is a linear function of composition, with δ7Li increasing by 1.0‰ for each mole per cent decrease in forsterite component. 相似文献
14.
Eleven surface soil samples from calcareous soils of industrial areas in Hamadan Province, western Iran were analyzed for
total concentrations of Zn, Cd, Ni, Cu and Pb and were sequentially extracted into six fractions to determine the bioavailability
of various heavy metal forms. Total Zn, Cd, Ni, Cu and Pb concentrations of the contaminated soils were 658 (57–5,803), 125.8
(1.18–1,361), 45.6 (30.7–64.4), 29.7 (11.7–83.5) and 2,419 (66–24,850) mg kg−1, respectively. The soils were polluted with Zn, Pb, and Cu to some extent and heavily polluted with Cd. Nickel values were
not above regulatory limits. Copper existed in soil mainly in residual (RES) and organic (OM) fractions (about 42 and 33%,
respectively), whereas Zn occurred essentially as RES fraction (about 69%). The considerable presence of Cd (30.8%) and Pb
(39%) in the CARB fraction suggests these elements have high potential biavailability and leachability in soils from contaminated
soils. The mobile and bioavailable (EXCH and CARB) fractions of Zn, Cd, Ni, Cu, and Pb in contaminated soils averaged (7.3,
40.4, 16, 12.9 and 40.8%), respectively, which suggests that the mobility and bioavailability of the five metals probably
decline in the following order: Cd = Pb > Ni > Cu > Zn. 相似文献
15.
16.
17.
Ni, Co, and Zn are widely distributed in the Earth’s mantle as significant minor elements that may offer insights into the chemistry of melting in the mantle. To better understand the distribution of Ni2+, Co2+, and Zn2+ in the most abundant silicate phases in the transition zone and the upper mantle, we have analyzed the crystal chemistry of wadsleyite (Mg2SiO4), ringwoodite (Mg2SiO4), forsterite (Mg2SiO4), and clinoenstatite (Mg2Si2O6) synthesized at 12–20 GPa and 1200–1400 °C with 1.5–3 wt% of either NiO, CoO, or ZnO in starting materials. Single-crystal X-ray diffraction analyses demonstrate that significant amounts of Ni, Co, and Zn are incorporated in octahedral sites in wadsleyite (up to 7.1 at%), ringwoodite (up to 11.3 at%), olivine (up to 2.0 at%), and clinoenstatite (up to 3.2 at%). Crystal structure refinements indicate that crystal field stabilization energy (CFSE) controls both cation ordering and transition metal partitioning in coexisting minerals. According to electron microprobe analyses, Ni and Co partition preferentially into forsterite and wadsleyite relative to coexisting clinoenstatite. Ni strongly prefers ringwoodite over coexisting wadsleyite with \({D}_{\text{Ni}}^{\text{Rw}/\text{Wd}}\)?=?4.13. Due to decreasing metal–oxygen distances with rising pressure, crystal field effect on distribution of divalent metal ions in magnesium silicates is more critical in the transition zone relative to the upper mantle. Analyses of Ni partitioning between the major upper-mantle phases implies that Ni-rich olivine in ultramafic rocks can be indicative of near-primary magmas. 相似文献
18.
塞曼原子吸收法测定大洋多金属结核中的铜钴镍 总被引:1,自引:0,他引:1
报道以HNO3-HF-HClO4分解多金属结核样品,用日立180-80偏振塞曼原子吸收分光光度计测定Cu、Co和Ni的方法。试验了介质及共存元素对测定的影响,选择了最佳测定条件。用该法测定了大洋锰结核标准物质中的Cu、Co、Ni,结果与标准值符合,且方法已应用于大批量样品分析中。对这些标样6次测定的RSD分别是Cu0.49% ̄1.99%,Co1.86% ̄2.66%,Ni0.46% ̄1.96%。 相似文献
19.
Sediments collected from a Norwegian anoxic fjord have been analyzed for Fe, Co, Cu, Mn, Ni and Zn. With the exception of Zn, the dominant factors effecting their distributions are the mineralogy of the land-derived lithogenic material and the abundance of organic matter. 相似文献
20.
W. A. Dollase 《Physics and Chemistry of Minerals》1998,25(5):389-392
The effects of composition and of temperature on the orthorhombic, Pca2
1
to cubic, F4ˉ3m transition of the stuffed cristobalite structure are reported. A distorton index which measures the departure of the orthorhombic
unit cell from a metrically cubic cell shows that at room temperature, distortion increases in the progression K2CdSiO4 <K2MgSiO4 <K2ZnSiO4≈K2CoSiO4. High temperature X-ray powder measurements document an apparently discontinuous transition to a structure of F4ˉ3m symmetry. Differential scanning calorimetry shows a sharp, reversible, first order transition to the high temperature phase
at about 500–600 °C for these compounds. Measured transformation enthalpies in the range of 7 to 16 J/g correlate roughly
with the distortion index. The transformation involves tetrahedral rotation to an orientationally disordered cubic structure
which retains an ordered M2+/Si distribution.
Received: 8 November 1996 / Revised, accepted: 14 October 1997 相似文献