吕梁地区宁家湾岩体锆石 U-Pb 年代学、地球化学特征及地质意义

对呈小规模岩株状产出的宁家湾岩体进行野外地质、岩石学、岩石地球化学、锆石U-Pb同位素年代学和Hf同位素组成研究, 目的是确定其岩石成因及地球动力学意义。两件样品的LA-ICP-MS锆石U-Pb定年结果分别为2364±6 Ma (MSWD=0.13)和2360±23 Ma (MSWD =4.0), 属古元古代岩浆活动的产物。研究结果表明, 宁家湾岩体富碱、高K和Si, 具有高FeO^T/MgO 比值和高的高场强元素(HFSE)含量, 富集Rb, Ba, Th和U等元素, 具有低的Ca和Mg含量, 明显亏损P和Ti, 具弱轻重稀土分异和强Eu负异常(δEu=0.13~0.36)的海鸥型稀土分配模式, 显示高分异I型花岗岩的特征。较高的Y/Nb值(1.2~2.8)、锆石的ε_Hf(t)均为正值(+1.6~+6.4)以及单阶段模式年龄t_DM1(Hf)和二阶段模式年龄t_DM2(Hf)分别为2449~2629 Ma和2474~2711 Ma的特点, 表明源区可能为壳幔混合。明显的Nb, P 和 Ti负异常及Ce, Nd和Zr正异常, 反映出大陆边缘弧岩浆岩的特征。结合区域地质背景, 认为宁家湾岩体很可能形成于岛弧构造环境。     

吕梁地区近周营组蚀变火山岩 U-Pb-Hf同位素特征及其地质意义

选择吕梁群中原岔上群北部地层的蚀变火山岩进行锆石U-Pb年代学和Hf同位素研究。锆石U-Pb测试获得两组年龄结果, 较年轻的谐和年龄为1813±6 Ma (n=7), 较老的²⁰⁷Pb/²⁰⁶Pb加权平均年龄为2516±31 Ma(n=2), 前者为火山岩喷发时代, 后者代表捕获锆石年龄。年轻锆石的ε_Hf(t)值为-10.8~-2.3, T_DM1值为2308~2655 Ma; 捕获锆石的ε_Hf(t)值为+10.0~+13.1。年龄约为2.5 Ga锆石的ε_Hf(t)值高于亏损地幔演化线, 考虑到UPb同位素和Hf同位素测点位置不完全相同, 说明所获得的Hf同位素组成为无地质意义的混合数值; 年龄约为1.8 Ga锆石的Hf同位素特征反映其可能源于富集地幔或受地壳物质混染的亏损地幔。结合前人的研究成果, 推断岩浆作用事件发生在约1.81 Ga 的碰撞后阶段。     

Azido chelating fiber: synthesis,characterization and adsorption performances towards Hg2+ and Pb2+ from water

Herein, we report the synthesis and adsorption property of a novel chelating fiber containing azido group. Firstly, the brominated fiber (PP‐St‐DVB‐Br) was obtained via the reaction of polypropylene‐(g)‐styrene‐divinylbenzene fiber (PP‐St‐DVB) with bromine in CH₂Cl₂ solution. Then, azido chelating fiber (PP‐St‐DVB‐N₃) was prepared by azidation of PP‐St‐DVB‐Br fiber. Its structure and properties were characterized by Fourier transform infrared, elemental analysis, thermogravimetric analysis, and chemical titration, respectively. The micromophology and functional group distribution in fibrous matrix were investigated by scanning electron microscopy‐energy dispersive spectroscopy. The results show that the chelating fiber has high functional group contents (2.11 mmol/g for PP‐St‐DVB‐N₃) and uniform distribution. Different from granulate chelating resin, the novel fibrous adsorbent possesses excellent adsorption ability for Hg(II) and Pb(II) ions (408.9 mg/g for Hg²⁺ and 334.4 mg/g for Pb²⁺), and the adsorption capacity of the fiber has no loss until five cycles. The novel absorbent material shows the potential application prospect in the treatment of heavy metal wastewater. Copyright © 2017 John Wiley & Sons, Ltd.     

Analytical methods to determine Po and Pb in marine samples

This paper describes the methods of sampling, preconcentration, chemical separation and final count of ²¹⁰Po and ²¹⁰Pb present in different marine matrices to determine their background levels in a marine ecosystem. Complex, time consuming and selective radioanalytical methods have been used to prepare final clear sources for alpha spectrometry and beta count; in fact, gamma spectrometry, a method direct and non destructive, cannot be taken into account because the ²¹⁰Pb activity is very low which does not allow to carry out sufficiently accurate measurements and ²¹⁰Po is not a gamma emitter but it emits only alpha particle at 5.40 MeV. The results of ²¹⁰Po and ²¹⁰Pb activity concentrations obtained in different marine samples collected in the first two campaigns are still very few to discuss about the ²¹⁰Po and ²¹⁰Pb behavior in marine environment.     

Electrochemical speciation of dissolved Cu, Pb and Zn in an estuarine ecosystem (Ria de Vigo, NW Spain): comparison between data treatment methods

The total concentration and chemical speciation of Cu, Pb and Zn were determined by square wave anodic stripping voltammetry (SWASV) in the Ría de Vigo, an estuarine area located in NW Spain. Surface and bottom waters from 6 locations were collected in two seasons during 3 years. The total Pb was below 1 nM, and Cu and Zn concentrations, ranged from 3 to 44 nM and from 9 to 300 nM respectively. A gradient from sampling points located in the port of Vigo to external areas was observed. The speciation of the metals (ligand concentration and apparent complex formation constant K′) was calculated using several methods: The Langmuir and Scatchard linear fits for one and two ligands, the Lorenzo non-linear fit for one ligand and Langmuir non-linear fit for two ligands. The capability of the different methods to achieve reliable results have been discussed and Langmuir linear fit as well as Lorenzo non-linear fit are the most suitable. Cu presented the highest ligand concentrations, followed by Zn and Pb, while mean log K′ values fell in the range 5-9 (±0.6) for all metals and samples. The adjustment of the data treatment methods used to calculate the speciation parameters was found to vary depending on the extent of complexation and on whether one or two ligands needed to be considered.     

A novel way to synthesize Pb nanotapes in liquid ammonia

Lead nanotapes were synthesized in liquid ammonia solvent in the presence of sodium metal at low temperature.The process was template free.Transmission electron microscopy(TEM) observations and X-ray diffraction(XRD) characterizations revealed that the as-prepared Pb nanotapes have average diameters in the range of 40-50 nm.and lengths up to several hundred nanometers, and exhibit cubic crystal structures.     

复合塑料包装袋中重金属迁移量的测定

将复合塑料袋用4％乙酸浸泡,采用石墨炉原子吸收光谱仪对其中的铅、镉、铬、镍、铜、砷迁移量进行了测定.结果表明:各元素的吸光度与质量浓度呈良好的线性关系,相关系数为0.998 9～0.9999,元素Pb、Cd、Cr、Ni、Cu、As的检出限分别为1.04、0.05、0.98、1.00、0.97、0.96 μg/L,各元素...     

LIBS结合单变量定标法对土壤中铅元素含量检测

重金属污染一直影响着人们的健康生活,如镉,铅和铜等的污染,故而土壤重金属的快速检测和如何预防,一直受各国学者关注和研究。传统土壤重金属检测方法（如原子吸收光谱法、X荧光光谱法等）样品预处理复杂,分析成本较高,易形成样品的二次污染,不能满足快速分析的要求。激光诱导击穿光谱（LIBS）是一种典型的原子发射光谱,它是基于分析物质中原子和离子受激发而发射的特征谱线信息,进而研究物质成分的分析方法。LIBS技术能够快速检测任何状态（固、液和气态）物质元素的成分和含量,被看作是未来化学检测和快速绿色分析领域的新兴技术。LIBS技术具有对样本简单预处理（或不需要处理）、多元素同步分析、远距离测量、适用性广等优势,被广泛用于生活生产的各个领域,已成为近年来国内外学者广泛关注和研究的热点之一。在农业信息快速感知的大背景下,以激光诱导击穿光谱技术为技术手段,以土壤重金属铅元素为研究对象,运用理论分析和数学建模相结合,建立了多种基于单变量定标曲线的土壤重金属铅检测模型,并进行了模型验证。自制15个已知的铅元素浓度梯度的谱线土壤样本,在获取了土壤LIBS数据之后,对其进行预处理对比,建立了基于谱峰强度、谱峰积分、洛伦兹拟合强度三种定标曲线模型,对土壤中铅元素含量进行定量分析,得出基于三种定标曲线模型对土壤中铅元素含量的预测决定系数R2分别为0.918 0,0.910 1和0.914 3,三种定标曲线分析方法的预测结果都较好,说明了LIBS结合单变量定标曲线法对土壤中铅含量的检测可靠性高。最后选取部分样本数据进行验证,结果较好。研究结果为研发便携式农田土壤污染物检测技术与装备提供技术支撑,也为农田精准管理和科学施肥奠定基础。