Geochemistry of rare earth elements in a marine influenced coal and its organic solvent extracts from the Antaibao mining district, Shanxi, China   总被引：2，自引：0，他引：2  

Wenfeng Wang  Yong Qin  Shuxun Sang  Yanming Zhu  Chaoyong Wang  Dominik J. Weiss 《International Journal of Coal Geology》2008,76(4):309-317

Twenty-six samples including roof, bottom and coal plies of a marine influenced coal bed were collected from the Antaibao mining district, Shanxi, China. The rare earth elements (REEs) were determined in solids and organic solvent extracts. The distribution pattern showed three distinct patterns: shale-like, LREE-rich and HREE-rich. This is attributed to the variable microenvironment of peat-forming swamp, the degree of marine influences and different REE sources. REEs in the coal are mainly controlled by detrital minerals but also affected by seawater. The chondrite-normalized REE patterns of the organic solvent extracts are distinctly different from those of corresponding original coal samples, which show a negative Eu anomaly, a depletion of middle REEs and an enrichment of HREEs. The LREEs in coal extracts are likely adsorbed by hydrogen-containing functional groups, and HREEs are likely bonded to carbon atoms.  相似文献   

Foreign Direct Investment,Ecological Withdrawals,and Natural-Resource-Dependent Economies     

Michael A. Long  Paul B. Stretesky  Michael J. Lynch 《社会与自然资源》2017,30(10):1261-1276

This article examines the relationships between foreign direct investment (FDI) and natural resource depletion and natural resource rents for a longitudinal (2005–2013: N?=?125 nations) sample of less developed countries (LDCs). Theoretically, we argue that FDI contributes to increased ecological withdrawals and dependence on the natural resource sector for economic growth within countries. We hypothesized that LDCs with higher levels of FDI would also have higher levels of natural resource depletion and income (i.e., rents). We assess whether this hypothesized relationship holds across nations in our sample for four different natural resource depletion and rents measures (energy, forest, mineral, and total natural resources). We find strong support for our hypotheses regarding natural resource depletion and resource rents, with the exception of energy rents. The outcome lends support to the ecological withdrawal and ecostructural theory of foreign investment dependence perspectives.  相似文献   

Toxicity-directed Fractionation of Tannery Wastewater Using Solid-phase Extraction and Luminescence Inhibition in Microtiter Plates     

O. Fiehn  L. Vigelahn  G. Kalnowski  T. Reemtsma  M. Jekel 《洁净——土壤、空气、水》1997,25(1):11-16

A four-step solid-phase extraction (SPE) method is presented for toxicity-directed fractionation of industrial wastewater. This fractionation procedure serves as a key step for identifying unknown organic toxicants in complex samples. Toxicity was determined as luminescence inhibition of Vibrio fischeri using microtiter plates. This method was compared to standard tests in glass cuvettes using both 37 standard chemicals and 24 wastewater fractions with EC₅₀ values covering five orders of magnitude. Results of both methods correlated well. 22 tannery wastewater samples were sequentially extracted using C₁₈e and polystyrene-divinylbenzene phases in combination with pH-changes. Final solid-phase filtrates showed low inhibition, so toxicity of inorganics could be neglected. Using 1/EC₅₀ values, the SPE eluates showed clearly different toxicity patterns. Even in eluates of the fourth extraction step, high toxic effects could be observed. In several cases, luminescence inhibition was increasing at the anaerobic treatment step compared to the corresponding untreated samples. After aerobic treatment, toxicity of most wastewater fractions was greatly diminished. HPLC/DAD analyses of the wastewater fractions showed a fair separation concerning compound polarity. However, the samples were still too complex to identify single compounds responsible for the detected toxicity. Therefore, a further clean-up step accompanied with toxicity testing is needed.  相似文献   

对电提取离子法找金适用性的看法     

谭登科 《铀矿地质》1990,6(2):113-115

本文介绍的找金新方法——电提取离子法,通过在已知金矿点上的试验,不仅取得了较好结果,更重要的是通过对提取电源的试验对比,证明选用微型电池(1.5V)进行提取也可获得满意结果,从而大大提高了方法的野外适用性。  相似文献   

溶剂萃取法分离锂同位素研究进展   总被引：2，自引：2，他引：0       下载免费PDF全文

肖江  贾永忠  姚颖  石成龙  孙进贺  谢绍雷  景燕 《盐湖研究》2016,24(3):62-72

锂同位素(6Li和7Li)在原子能工业中占据着重要的地位。在众多锂同位素的分离方法和体系中,溶剂萃取法是一种具有较高分离系数,并最有望实现无毒、高效分离的工业生产方法。阐述了溶剂萃取法分离锂同位素的原理,综述了醇类与酮类、烷基膦与膦酸脂类、冠醚类及其它溶剂萃取体系在锂同位素分离中的研究现状及趋势,并展望了溶剂萃取法在锂同位素分离和未来青海、西藏盐湖锂资源高值化利用中的潜在应用前景。  相似文献   

正交设计法提取江蓠高活性膳食纤维     

李来好  陈培基  杨贤庆 《广东海洋大学学报》2000,20(1)

采用正交设计法 ,研究了江蓠高活性膳食纤维的提取工艺条件 ,筛选出江蓠碱处理和漂白的最佳工艺条件 ,提取出江蓠高活性膳食纤维。结果表明 ,江蓠高活性膳食纤维的产率达 2 8.3% ,颜色较白 ,膳食纤维干基质量分数达 92 .83% ,钙质量分数 1.0 8% ,磷质量分数 0 .0 6 8% ,膨胀力为 9.0 m L / g,持水力为 82 5% ,质量和功能性指标远远超过西方国家麸皮膳食纤维的标准 (膳食纤维干基质量分数 4 7%、膨胀力 4 m L/ g、持水力 4 0 0 % )  相似文献   

Comparison of techniques for pre-concentrating radium from seawater     

M. Bourquin  P. van Beek  J.-L. Reyss  M. Souhaut  M.A. Charette  C. Jeandel 《Marine Chemistry》2008,109(3-4):226

In the framework of the KEOPS project (KErguelen: compared study of the Ocean and the Plateau in Surface water), we aimed to provide information on the water mass pathways and vertical mixing on the Kerguelen Plateau, Southern Ocean, based on ²²⁸Ra profiles. Because ²²⁸Ra activities are extremely low in this area (~ 0.1 dpm/100 kg or ~ 2.10^− 18 g kg^− 1), the filtration of large volumes of seawater was required in order to be able to detect it with minimal uncertainty. This challenging study was an opportunity for us to test and compare methods aimed at removing efficiently radium isotopes from seawater. We used Mn-fiber that retains radium and that allows the measurement of all four radium isotopes (²²⁶Ra, ²²⁸Ra, ²²³Ra, ²²⁴Ra). First, we used Niskin bottles or the ship's seawater intake to collect large volumes of seawater that were passed onto Mn-fiber in the laboratory. Second, we filled cartridges with Mn-fiber that we placed in tandem on in situ pumps. Finally, we fixed nylon nets filled with Mn-fiber on the frame of in situ pumps to allow the passive filtration of seawater during the pump deployment.Yields of radium fixation on the cartridges filled with Mn-fiber and placed on in situ pumps are ca. 30% when combining the two cartridges. Because large volumes of seawater can be filtered with these pumps, this yields to effective volumes of 177–280 kg (that is, higher than that recovered from fourteen 12-l Niskin bottles). Finally, the effective volume of seawater that passed through Mn-fiber placed in nylon nets and deployed during 4 h ranged between 125 and 364 kg. Consequently, the two techniques that separate Ra isotopes in situ are good alternatives for pre-concentrating radium from seawater. They can save ship-time by avoiding repeated CTD casts to obtain the large volumes of seawater. This is especially true when in situ pumps are deployed to collect suspended particles. However, both methods only provide ²²⁸Ra/²²⁶Ra ratios. The determination of the ²²⁸Ra specific activity is obtained by multiplying this ratio by the ²²⁶Ra activity measured in a discrete sample collected at the same water depth.  相似文献   

基于高分辨率影像的江北区土地利用变化监测     

徐财江  陈志荣 《国土资源信息化》2009,(2)

以2005年和2006年两期SPOT影像,结合06年土地利用变更调查成果,进行宁波市江北区的土地利用变化监测研究。本文重点介绍了直接影响土地利用变化信息提取精度的遥感影像几何校正和相对辐射校正方法,在对遥感影像数据处理基础上,叠加土地利用现状数据,以人机交互的方式进行土地利用变化信息的提取,通过对监测结果的分析,验证了利用高分辨率影像实现土地利用变化监测的可行性。  相似文献   

苯并15-冠-5—离子液体体系多级逆流萃取分离锂同位素研究          下载免费PDF全文

王兴权  贾永忠  姚颖  肖江  王苏  景燕 《盐湖研究》2019,27(4):70-76

锂的两种天然同位素(~6Li和~7Li)在能源、环境和国防安全等领域具有重要应用价值。以氯化锂溶液为原料,选用苯并15-冠-5和咪唑类离子液体体系对其进行了模拟逆流萃取实验,考察了多级逆流萃取过程中锂的萃取率和锂同位素分离系数的变化规律。同时,对锂同位素富集浓度和富集行为进了研究探讨。结果表明,经10级逆流萃取后,锂的萃取率和同位素分离系数有了明显提高,~6Li富集在有机相,丰度提高了0.299 6%。  相似文献   

过硫酸钠修复土壤中多环芳烃的准确测定     

杨清 《岩矿测试》2022,(3):404-411

多环芳烃(PAHs)是一类具有致癌、致突变、致畸的碳氢化合物,具有较高的辛醇-水分配系数,易被土壤颗粒吸附而影响环境和人体健康。过硫酸钠(Na₂S₂O₈)氧化法是近些年来国内外修复PAHs污染土壤较为常用的方法,但现阶段在测定修复后土壤中PAHs含量、进行土壤修复效果评估时亟待解决的问题是：经该方法修复的土壤,若土壤中残留有过硫酸钠,在样品前处理过程中由于提取温度较高,可能会进一步加速多环芳烃的氧化反应,从而影响土壤中PAHs的准确测定。本文建立了一种在修复后土壤中加入还原剂抗坏血酸,与残留的过硫酸钠反应生成脱氢抗坏血酸,采用索氏提取结合气相色谱-质谱法(GC-MS)同时测定土壤中16种PAHs的方法,PAHs加标回收率为76.2%～110.0%。而修复后土壤若不加还原剂直接进行索氏提取,用GC-MS测定,可能会使部分PAHs及替代物的测定不准确,PAHs加标回收率仅为6.0%～72.4%。通过对比分析表明,在样品提取前加入还原剂,可以有效地消除残留过硫酸钠的影响,提高测定修复后土壤中PAHs含量的准确性。  相似文献