Science.gov

Sample records for pb cu sb

  1. Room-Temperature Indentation Creep and the Mechanical Properties of Rapidly Solidified Sn-Sb-Pb-Cu Alloys

    NASA Astrophysics Data System (ADS)

    Kamal, Mustafa; El-Bediwi, A.; Lashin, A. R.; El-Zarka, A. H.

    2016-05-01

    In this paper, we study the room-temperature indentation creep and the mechanical properties of Sn-Sb-Pb-Cu alloys. Rapid solidification from melt using the melt-spinning technique is applied to prepare all the alloys. The experimental results show that the magnitude of the creep displacement increases with the increase in both time and applied load, and the stress exponent increases with the increase in the copper content in the alloys which happens primarily due to the existence of the intermetallic compounds SbSn and Cu6Sn5. The calculated values of the stress exponent are in the range of 2.82 to 5.16, which are in good agreement with the values reported for the Sn-Sb-Pb-Cu alloys. We have also studied and analyzed the structure, elastic modulus, and internal friction of the Sn-Sb-Pb-Cu alloys.

  2. Bioaccessibility of As, Cd, Cu, Ni, Pb, and Sb in toys and low-cost jewelry.

    PubMed

    Guney, Mert; Zagury, Gerald J

    2014-01-21

    Children can be exposed to toxic elements in toys and jewelry following ingestion. As, Cd, Cu, Ni, Pb, and Sb bioavailability was assessed (n = 24) via the in vitro gastrointestinal protocol (IVG), the physiologically based extraction test (PBET), and the European Toy Safety Standard protocol (EN 71-3), and health risks were characterized. Cd, Cu, Ni, and Pb were mobilized from 19 metallic toys and jewelry (MJ) and one crayon set. Bioaccessible Cd, Ni, or Pb exceeded EU migratable concentration limits in four to six MJ, depending on the protocol. Using two-phase (gastric + intestinal) IVG or PBET might be preferable over EN 71-3 since they better represent gastrointestinal physiology. Bioaccessible and total metal concentrations were different and not always correlated, indicating that bioaccessibility measurement may provide more accurate risk characterization. More information on impacts of multiple factors affecting metals mobilization from toys and jewelry is needed before recommending specific tests. Hazard index (HI) for Cd, Ni, or Pb were >1 for all six MJ exceeding the EU limits. For infants (6-12 mo old), 10 MJ had HI > 1 for Cd, Cu, Ni, or Pb (up to 75 for Cd and 43 for Pb). Research on prolonged exposure to MJ and comprehensive risk characterization for toys and jewelry exposure is recommended. PMID:24345102

  3. A systematic study of superconductivity in BiPb(Sn)-Sb Sr-Ca-Cu-O systems

    NASA Technical Reports Server (NTRS)

    Akbar, Sheikh A.; Botelho, M. J.; Wong, M. S.; Alauddin, M.

    1990-01-01

    Superconducting transition above 160 K has been reported in the Bi-Pb-Sb-Sr-Ca-Cu-O system. Results of a systematic study emphasizing the correlations between the type and amount of dopant, and superconducting transition is presented. The effect of Sn (instead of Pb) substitution is also highlighted.

  4. Accumulation of Sb, Pb, Cu, Zn and Cd by various plants species on two different relocated military shooting range soils.

    PubMed

    Evangelou, Michael W H; Hockmann, Kerstin; Pokharel, Rasesh; Jakob, Alfred; Schulin, Rainer

    2012-10-15

    Annually, more than 400 t Pb and 10 t Sb enter Swiss soils at some 2000 military shooting ranges. After the decommission of military shooting ranges, heavily contaminated soils (>2000 mg kg(-1) Pb) are landfilled or processed by soil washing, whereas for soils with less contamination, alternate strategies are sought. Although the use of military shooting ranges for grazing in Switzerland is common practice, no assessment has been done about the uptake of Sb in plants and its subsequent potential intake by grazing animals. We determined the uptake of Sb, Pb, Cu, Zn and Cd in the aboveground biomass of nine plant species growing on a calcareous (Chur) and a weakly acidic (Losone) military shooting range soil in order to assess if grazing would be safe to employ on decommissioned military shooting ranges. The two soils did not differ in their total concentrations of Cu, Zn, Sb and Cd, they differed however in the total concentration of Pb. Additionally, their physical and chemical properties were significantly different. The accumulation of Zn, Cu, Cd and Pb in the shoots of all nine plant species remained below the Swiss tolerance values for fodder plants (150 mg kg(-1) Zn, 15-35 mg kg(-1) Cu, 40 mg kg(-1) Pb, and 1 mg kg(-1) Cd DW), with the only exception of Pb in Chenopodium album shoots which reached a concentration of 62 mg kg(-1) DW. Antimony concentrations were 1.5-2.6-fold higher in plants growing on the calcareous soil than on the weakly acidic soil. Considering Cu, Zn, Pb, Sb and Cd, all plants, with the exception C. album, would be suitable for grazing on similar shooting range soils. PMID:22659605

  5. Comparative modular analysis of two complex sulfosalt structures: sterryite, Cu(Ag,Cu)3Pb19(Sb,As)22(As-As)S56, and parasterryite, Ag4Pb20(Sb,As)24S58.

    PubMed

    Moëlo, Yves; Guillot-Deudon, Catherine; Evain, Michel; Orlandi, Paolo; Biagioni, Cristian

    2012-10-01

    The crystal structures of two very close, but distinct complex minerals of the lead sulfosalt group have been solved: sterryite, Cu(Ag,Cu)(3)Pb(19)(Sb,As)(22)(As-As)S(56), and parasterryite, Ag(4)Pb(20)(Sb,As)(24)S(58). They are analyzed and compared according to modular analysis. The fundamental building block is a complex column centred on a Pb(6)S(12) triangular prismatic core, with two additional long and short arms. The main chemical and topological differences relate to the short arm, which induces a relative a/4 shift (~2 Å along the elongation parameter) of the constitutive rod layers, as illustrated by distinct cell settings within the same space group (P2(1)/n and P2(1)/c, respectively). Selection of the shortest (i.e. strongest) (Sb,As)-S bonds permitted to enhance the polymeric organization of (Sb,As) atoms with triangular pyramidal coordination. These two quasi-homeotypic structures are expanded derivatives of owyheeite, Ag(3)Pb(10)Sb(11)S(28). The hierarchy of organization levels from zero- to three-dimensional entities is subordinated to building operators, which appear as the driving force for the construction of such complex structures. Minor cations (Ag, Cu) or the As-As pair in sterryite secure the final locking, which favours the formation of one or the other compound. PMID:22992793

  6. Bournonite PbCuSbS3 : Stereochemically Active Lone-Pair Electrons that Induce Low Thermal Conductivity.

    PubMed

    Dong, Yongkwan; Khabibullin, Artem R; Wei, Kaya; Salvador, James R; Nolas, George S; Woods, Lilia M

    2015-10-26

    An understanding of the structural features and bonding of a particular material, and the properties these features impart on its physical characteristics, is essential in the search for new systems that are of technological interest. For several relevant applications, the design or discovery of low thermal conductivity materials is of great importance. We report on the synthesis, crystal structure, thermal conductivity, and electronic-structure calculations of one such material, PbCuSbS3 . Our analysis is presented in terms of a comparative study with Sb2 S3 , from which PbCuSbS3 can be derived through cation substitution. The measured low thermal conductivity of PbCuSbS3 is explained by the distortive environment of the Pb and Sb atoms from the stereochemically active lone-pair s(2) electrons and their pronounced repulsive interaction. Our investigation suggests a general approach for the design of materials for phase-change-memory, thermal-barrier, thermal-rectification and thermoelectric applications, as well as other functions for which low thermal conductivity is purposefully sought. PMID:26330172

  7. Contents and leachability of heavy metals (Pb, Cu, Sb, Zn, As) in soil at the Pantex firing range, Amarillo, Texas.

    PubMed

    Basunia, S; Landsberger, S

    2001-10-01

    Pantex firing range soil samples were analyzed for Pb, Cu, Sb, Zn, and As. One hundred ninety-seven samples were collected from the firing range and vicinity area. There was a lack of knowledge about the distribution of Pb in the firing range, so a random sampling with proportional allocation was chosen. Concentration levels of Pb and Cu in the firing range were found to be in the range of 11-4675 and 13-359 mg/kg, respectively. Concentration levels of Sb were found to be in the range of 1-517 mg/kg. However, the Zn and As concentration levels were close to average soil background levels. The Sn concentration level was expected to be higher in the Pantex firing range soil samples. However, it was found to be below the neutron activation analysis (NAA) detection limit of 75 mg/kg. Enrichment factor analysis showed that Pb and Sb were highly enriched in the firing range with average magnitudes of 55 and 90, respectively. Cu was enriched approximately 6 times more than the usual soil concentration levels. Toxicity characteristic leaching procedure (TCLP) was carried out on size-fractionated homogeneous soil samples. The concentration levels of Pb in leachates were found to be approximately 12 times higher than the U.S. Environmental Protection Agency (EPA) regulatory concentration level of 5 mg/L. Sequential extraction (SE) was also performed to characterize Pb and other trace elements into five different fractions. The highest Pb fraction was found with organic matter in the soil. PMID:11686247

  8. Geospatial Mapping of Pb, Cr, Cu, Zn, Cd, and Sb in Urban Soil, Cd. Juarez, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Amaya, M. A.; Grimida, S. E.; Elkekli, A. R.; Aldouri, R. K.; Benedict, B. A.; Pingitore, N. E., Jr.

    2015-12-01

    Population-based random stratified sampling of the city of Cd. Juarez, Chihuahua, Mexico provided 500 city blocks for study. We collected soil from the public space (where present) in front of each house on a selected block; equal measured small volumes of these were combined to produce a composite sample for analysis. Such composite samples (1) decrease, by an order of magnitude, laboratory processing and analysis costs, and (2) smooth the data to represent blocks as averages of individual houses. Retention of the unanalyzed samples of the individual houses permits their later analysis should the composites suggest further study of individual houses on an anomalous block. Elemental analysis of 10 mg pressed powders was performed on a Panalytical Epsilon5 EDS-XRF, via 8 secondary targets and 12 USGS and NIST multi-element rock standards. The mean and (range) of concentration for Pb was 43 (13-550) ppm; for Cr, 31 (1.8-76); for Cu, 22 (6-550); for Zn 84 (42-415) ppm; for Cd, 1.9 (0.1-6.2); and for Sb, 5.9 (2.7-29). The old urban core of Cd. Juarez was marked by high levels of Pb, Cr, Cu, and Zn, and, to a smaller degree, of Cd and Sb. This pattern mirrors that of contiguous El Paso, Texas, USA, directly across the narrow Rio Grande. Businesses, industrial facilities, transportation (both railroads and highways), traditional "downtown" shopping, and old residential districts cluster in this urban core. A Pb-Cu-Zn smelter, which operated for more than a century until 1999, is present in the US adjacent to the Rio Grande, about two km away from downtown Cd. Juarez. Thus the city has been subject to both traditional metal sources (e.g., leaded gasoline, highway debris) and smelter emissions. The poplation of Cd. Juarez has exploded in the last few decades to some 1.5 million inhabitants due both to natural growth and in-migration from rural districts for economic opportunity. Most of this growth has been accommodated by radial expansion of the city into the surrounding

  9. Influence of simultaneous doping of Sb and Pb on phase formation, superconducting and microstructural characteristics of HgBa 2Ca 2Cu 3O 8+ δ

    NASA Astrophysics Data System (ADS)

    Giri, Rajiv; Tiwari, R. S.; Srivastava, O. N.

    2007-01-01

    We report systematic studies of structural, microstructural and transport properties of (Hg 0.80Sb 0.2- xPb x)Ba 2Ca 2Cu 3O 8+ δ (where x = 0.0, 0.05, 0.1, 0.15, 0.2) compounds. Bulk polycrystalline samples have been prepared by two-step solid-state reaction route at ambient pressure. It has been observed that simultaneous substitution of Sb and Pb at Hg site in oxygen deficient HgO δ layer of HgBa 2Ca 2Cu 3O 8+ δ cuprate high- Tc superconductor leads to the formation of Hg-1223 as the dominant phase. Microstructural investigations of the as grown samples employing scanning electron microscopy reveal single crystal like large grains embodying spiral like features. Superconducting properties particularly transport current density ( Jct) have been found to be sensitive to these microstructural features. As for example (Hg 0.80Sb 0.05Pb 0.15)Ba 2Ca 2Cu 3O 8+ δ compound which exhibits single crystal like large grains (∼50 μm) and appears to result through spiral growth mechanism, shows highest Jct (∼1.85 × 10 3 A/cm 2) at 77 K. A possible mechanism for the generation of spiral like features and correlation between microstructural features and superconducting properties have been put forward.

  10. Molar and excess volumes of liquid In-Sb, Mg-Sb, and Pb-Sb alloys

    SciTech Connect

    Hansen, A.R.; Kaminski, M.A. ); Eckert, C.A. )

    1990-04-01

    By a direct Archimedes' technique, volumetric data were obtained for liquid In, Mg, Pb, and Sb and mixtures of In-Sb, Mg-Sb, and Pb-Sb. In this paper the excess volumes for the alloys studied are presented and discussed.

  11. Antimony (Sb) and lead (Pb) in contaminated shooting range soils: Sb and Pb mobility and immobilization by iron based sorbents, a field study.

    PubMed

    Okkenhaug, Gudny; Grasshorn Gebhardt, Karl-Alexander; Amstaetter, Katja; Bue, Helga Lassen; Herzel, Hannes; Mariussen, Espen; Rossebø Almås, Åsgeir; Cornelissen, Gerard; Breedveld, Gijs D; Rasmussen, Grete; Mulder, Jan

    2016-04-15

    Small-arm shooting ranges often receive a significant input of lead (Pb), copper (Cu) and antimony (Sb) from ammunition. The goal of the present study was to investigate the mobility, distribution and speciation of Pb and Sb pollution under field conditions in both untreated and sorbent-amended shooting range soil. Elevated Sb (19-349μgL(-1)) and Pb (7-1495μgPbL(-1)) concentrations in the porewater of untreated soil over the four-year test period indicated a long-term Sb and Pb source to the adjacent environment in the absence of remedial measures. Mixing ferric oxyhydroxide powder (CFH-12) (2%) together with limestone (1%) into the soil resulted in an average decrease of Sb and Pb porewater concentrations of 66% and 97%, respectively. A similar reduction was achieved by adding 2% zerovalent iron (Fe°) to the soil. The remediation effect was stable over the four-year experimental period indicating no remobilization. Water- and 1M NH4NO3-extractable levels of Sb and Pb in field soil samples indicated significant immobilization by both treatments (89-90% for Sb and 89-99% for Pb). Results from sequential extraction analysis indicate fixation of Sb and Pb in less accessible fractions like amorphous iron oxides or even more crystalline and residual mineral phases, respectively. This work shows that amendment with Fe-based sorbents can be an effective method to reduce the mobility of metals both in cationic and anionic form in polluted shooting range soil. PMID:26799225

  12. A rapid, partial leach and organic separation for the sensitive determination of Ag, Bi, Cd, Cu, Mo, Pb, Sb, and Zn in surface geologic materials by flame atomic absorption

    USGS Publications Warehouse

    Viets, J.G.; Clark, J.R.; Campbell, W.L.

    1984-01-01

    A solution of dilute hydrochloric acid, ascorbic acid, and potassium iodide has been found to dissolve weakly bound metals in soils, stream sediments, and oxidized rocks. Silver, Bi, Cd, Cu, Mo, Pb, Sb, and Zn are selectively extracted from this solution by a mixture of Aliquat 336 (tricaprylyl methyl ammonium chloride) and MIBK (methyl isobutyl ketone). Because potentially interfering major and minor elements do not extract, the organic separation allows interference-free determinations of Ag and Cd to the 0.05 ppm level, Mo, Cu, and Zn to 0.5 ppm, and Bi, Pb, and Sb to 1 ppm in the sample using flame atomic absorption spectroscopy. The analytical absorbance values of the organic solution used in the proposed method are generally enhanced more than threefold as compared to aqueous solutions, due to more efficient atomization and burning characteristics. The leaching and extraction procedures are extremely rapid; as many as 100 samples may be analyzed per day, yielding 800 determinations, and the technique is adaptable to field use. The proposed method was compared to total digestion methods for geochemical reference samples as well as soils and stream sediments from mineralized and unmineralized areas. The partial leach showed better anomaly contrasts than did total digestions. Because the proposed method is very rapid and is sensitive to pathfinder elements for several types of ore deposits, it should be useful for reconnaissance surveys for concealed deposits. ?? 1984.

  13. Comparison Study of Transition Temperature between the Superconducting Compounds Tl0.9 Pb0.1 Ba2Ca2Cu3O9-δ, Tl0.9Sb0.1Ba2Ca2Cu3O9-δ and Tl0.9Cr0.1Ba2Ca2Cu3O9-δ

    NASA Astrophysics Data System (ADS)

    Jasim, Kareem Ali; Makki, Sameer Atta; Almohsin, Alia abud

    Three high temperature superconductors namely Tl0.9Pb0.1Ba2Ca2Cu3O9-δ, Tl0.9Sb0.1Ba2Ca2Cu3O9-δ and Tl0.9Cr0.1Ba2Ca2Cu3O9-δ have been successfully prepared by three-step solid state reaction method. The sintering was within (1128-1133) K. Electrical resistively, using four probe techniques, is used to find the transition temperature Tc. The transition temperature at zero resistivity Tc(offset) were 110, 115 and 118K, onset superconducting transition temperature Tc(onset) were 128, 131 and 132 K for Tl0.9Cr0.1Ba2Ca2Cu3O9-δ, Tl0.9Sb0.1Ba2Ca2Cu3O9-δ and Tl0.9Cr0.1Ba2Ca2Cu3O9-δ respectively. All samples preparation with O2 flow. X-ray diffraction (XRD) analysis showed a pesudotetragonal structure with changes of lattice parameters for these samples.

  14. Partitioning of V, Mn, Co, Ni, Cu, Zn, As, Mo, Ag, Sn, Sb, W, Au, Pb, and Bi between sulfide phases and hydrous basanite melt at upper mantle conditions

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Audétat, Andreas

    2012-11-01

    The partitioning of 15 major to trace metals between monosulfide solid solution (MSS), sulfide liquid (SL) and mafic silicate melt (SM) was determined in piston-cylinder experiments performed at 1175-1300 °C, 1.5-3.0 GPa and oxygen fugacities ranging from 3.1 log units below to 1.0 log units above the quartz-fayalite-magnetite fO2 buffer, which conditions are representative of partial melting in the upper mantle in different tectonic settings. The silicate melt was produced by partial melting of a natural, amphibole-rich mantle source rock, resulting in hydrous (˜5 wt% H2O) basanitic melts similar to low-degree partial melts of metasomatized mantle, whereas the major element composition of the starting sulfide (˜52 wt% Fe; 39 wt% S; 7 wt% Ni; 2 wt% Cu) was similar to the average composition of sulfides in this environment. SL/SM partition coefficients are high (≥100) for Au, Ni, Cu, Ag, Bi, intermediate (1-100) for Co, Pb, Sn, Sb (±As, Mo), and low (≤1) for the remaining elements. MSS/SM partition coefficients are generally lower than SL/SM partition coefficients and are high (≥100) for Ni, Cu, Au, intermediate (1-100) for Co, Ag (±Bi, Mo), and low (≤1) for the remaining elements. Most sulfide-silicate melt partition coefficients vary as a function of fO2, with Mo, Bi, As (±W) varying by a factor >10 over the investigated fO2 range, Sb, Ag, Sn (±V) varying by a factor of 3-10, and Pb, Cu, Ni, Co, Au, Zn, Mn varying by a factor of 3-10. The partitioning data were used to model the behavior of Cu, Au, Ag, and Bi during partial melting of upper mantle and during fractional crystallization of primitive MORB and arc magmas. Sulfide phase relationships and comparison of the modeling results with reported Cu, Au, Ag, and Bi concentrations from MORB and arc magmas suggest that: (i) MSS is the dominant sulfide in the source region of arc magmas, and thus that Au/Cu ratios in the silicate melt and residual sulfides may decrease with increasing degree of

  15. Effects of temperature, silicate melt composition, and oxygen fugacity on the partitioning of V, Mn, Co, Ni, Cu, Zn, As, Mo, Ag, Sn, Sb, W, Au, Pb, and Bi between sulfide phases and silicate melt

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Audétat, Andreas

    2015-08-01

    In order to assess the role of sulfide in controlling the ore metal budgets and fractionation during magmatic genesis and differentiation, the partition coefficients (D) of V, Mn, Co, Ni, Cu, Zn, As, Mo, Ag, Sn, Sb, W, Au, Pb, and Bi between sulfide liquid (SL), monosulfide solid solution (MSS), and basaltic to rhyolitic melts (SM) were determined at 900-1200 °C, 0.5-1.5 GPa, and oxygen fugacity (fO2) ranging from ∼FMQ-2 to FMQ+3, in a piston-cylinder apparatus. The DSL/SM values range from 0.4 to 2 for V, 0.5 to 3 for Mn, 80 to 580 for Co, 2300 to 18,000 for Ni, 800 to 4600 for Cu, 1 to 11 for Zn, 20 to 180 for As, 4 to 230 for Mo, 450 to 1600 for Ag, 5 to 24 for Sn, 10 to 80 for Sb, 0.03 to 0.16 for W, 2000 to 29,000 for Au, 24 to 170 for Pb, and 830 to 11,000 for Bi; whereas the DMSS/SM values range from 0.04 to 10 for V, 0.5 to 10 for Mn, 70 to 2500 for Co, 650 to 18,000 for Ni, 280 to 42,000 for Cu, 0.1 to 80 for Zn, 0.2 to 30 for As, 1 to 820 for Mo, 20 to 500 for Ag, 0.2 to 220 for Sn, 0.1 to 40 for Sb, 0.01 to 24 for W, 10 to 2000 for Au, 0.03 to 6 for Pb, and 1 to 350 for Bi. Both DMSS/SM and DSL/SM values generally increase with decreasing temperature or decreasing FeOtot content in silicate melt, except for Mo, DMSS/SM and DSL/SM of which show a clear decrease with decreasing temperature. At given temperature and FeOtot content, high oxygen fugacity appears to lead to a significant decrease in DMSS/SM of Au, Bi, Mo, and potentially As. The partitioning data obtained experimentally in this study and previous studies were fitted to an empirical equation that expresses the DMSS/SM and/or DSL/SM of a given element as a function of temperature, oxygen fugacity, and FeOtot content of the silicate melt: log (DSL/SMorDMSS/SM = d + a · 10, 000 / T + b · (ΔFMQ) + c · log (FeOmelt) in which T is temperature in K, FeOmelt denotes wt% FeOtot in silicate melt, and ΔFMQ denotes log fO2 relative to the fayalite-magnetite-quartz (FMQ) oxygen buffer. The

  16. Controlled CVD growth of Cu-Sb alloy nanostructures

    NASA Astrophysics Data System (ADS)

    Chen, Jing; Yin, Zongyou; Sim, Daohao; Tay, Yee Yan; Zhang, Hua; Ma, Jan; Hng, Huey Hoon; Yan, Qingyu

    2011-08-01

    Sb based alloy nanostructures have attracted much attention due to their many promising applications, e.g. as battery electrodes, thermoelectric materials and magnetic semiconductors. In many cases, these applications require controlled growth of Sb based alloys with desired sizes and shapes to achieve enhanced performance. Here, we report a flexible catalyst-free chemical vapor deposition (CVD) process to prepare Cu-Sb nanostructures with tunable shapes (e.g. nanowires and nanoparticles) by transporting Sb vapor to react with copper foils, which also serve as the substrate. By simply controlling the substrate temperature and distance, various Sb-Cu alloy nanostructures, e.g. Cu11Sb3 nanowires (NWs), Cu2Sb nanoparticles (NPs), or pure Sb nanoplates, were obtained. We also found that the growth of Cu11Sb3 NWs in such a catalyst-free CVD process was dependent on the substrate surface roughness. For example, smooth Cu foils could not lead to the growth of Cu11Sb3 nanowires while roughening these smooth Cu foils with rough sand papers could result in the growth of Cu11Sb3 nanowires. The effects of gas flow rate on the size and morphology of the Cu-Sb alloy nanostructures were also investigated. Such a flexible growth strategy could be of practical interest as the growth of some Sb based alloy nanostructures by CVD may not be easy due to the large difference between the condensation temperature of Sb and the other element, e.g. Cu or Co.

  17. Controlled CVD growth of Cu-Sb alloy nanostructures.

    PubMed

    Chen, Jing; Yin, Zongyou; Sim, Daohao; Tay, Yee Yan; Zhang, Hua; Ma, Jan; Hng, Huey Hoon; Yan, Qingyu

    2011-08-12

    Sb based alloy nanostructures have attracted much attention due to their many promising applications, e.g. as battery electrodes, thermoelectric materials and magnetic semiconductors. In many cases, these applications require controlled growth of Sb based alloys with desired sizes and shapes to achieve enhanced performance. Here, we report a flexible catalyst-free chemical vapor deposition (CVD) process to prepare Cu-Sb nanostructures with tunable shapes (e.g. nanowires and nanoparticles) by transporting Sb vapor to react with copper foils, which also serve as the substrate. By simply controlling the substrate temperature and distance, various Sb-Cu alloy nanostructures, e.g. Cu(11)Sb(3) nanowires (NWs), Cu(2)Sb nanoparticles (NPs), or pure Sb nanoplates, were obtained. We also found that the growth of Cu(11)Sb(3) NWs in such a catalyst-free CVD process was dependent on the substrate surface roughness. For example, smooth Cu foils could not lead to the growth of Cu(11)Sb(3) nanowires while roughening these smooth Cu foils with rough sand papers could result in the growth of Cu(11)Sb(3) nanowires. The effects of gas flow rate on the size and morphology of the Cu-Sb alloy nanostructures were also investigated. Such a flexible growth strategy could be of practical interest as the growth of some Sb based alloy nanostructures by CVD may not be easy due to the large difference between the condensation temperature of Sb and the other element, e.g. Cu or Co. PMID:21757793

  18. Thermal Treatment Improvement of CuSbS2 Absorbers

    SciTech Connect

    de Souza Lucas, Francisco Willian; Welch, Adam W.; Baranowski, Lauryn L.; Dippo, Patricia C.; Mascaro, Lucia H.; Zakutayev, Andriy

    2015-06-14

    Thermal treatment in Sb2S3 vapor was used to improve the quality of CuSbS2 thin films, a promising non-toxic and earth-abundant absorber. A change in the CuSbS2 crystallographic texture and a decrease in the lattice stress were observed, as well as increases in the grain size, photoluminescence intensity and photoconductivity. To eliminate the influence of the possible Sb2S3 rich surface layer on photovoltaic performance, a selective chemical etching with KOH was developed.

  19. Channel formation in Pb-Sn, Pb-Sb, and Pb-Sn-Sb alloy ingots and comparison with the system NH4Cl-H2O

    NASA Technical Reports Server (NTRS)

    Hellawell, A.; Sarazin, J. R.

    1988-01-01

    The formation of segregation channels during the unidirectional solidification of base chilled ingots has been studied as a function of composition in binary Pb-Sn and Pb-Sb and ternary Pb-Sn-Sb alloys. The patterns of channel distribution were characterized in the binary and ternary systems and are described as functions of temperature gradients, growth rates, dendrite spacings, and interdendritic permeabilities. Channels appear to nucleate at random across a dendritic front and subsequently to interact as they propagate, decreasing in density across the front. Assuming that the interdendritic spacing is the characteristic distance for a liquid perturbation, yields critical effective Rayleigh numbers which lie within a factor of x 40 for both metallic and aqueous systems. This correlation is close, considering the sensitivity to any assumed dimension and the range of material properties involved, and is taken to support a model for channel nucleation occurring close to the dendritic growth front.

  20. Formation mechanism of primary phases and eutectic structures within undercooled Pb-Sb-Sn ternary alloys

    NASA Astrophysics Data System (ADS)

    Wang, Weili; Dai, Fuping; Wei, Bingbo

    2007-08-01

    The solidification characteristics of three types of Pb-Sb-Sn ternary alloys with different primary phases were studied under substantial undercooling conditions. The experimental results show that primary (Pb) and SbSn phases grow in the dendritic mode, whereas primary (Sb) phase exhibits faceted growth in the form of polygonal blocks and long strips. (Pb) solid solution phase displays strong affinity with SbSn intermetallic compound so that they produce various morphologies of pseudobinary eutectics, but it can only grow in the divorced eutectic mode together with (Sb) phase. Although (Sb) solid solution phase and SbSn intermetallic compound may grow cooperatively within ternary eutectic microstructures, they seldom form pseudobinary eutectics independently. The (Pb)+(Sb)+SbSn ternary eutectic structure usually shows lamellar morphology, but appears as anomalous eutectic when its volume fraction becomes small. EDS analyses reveal that all of the three primary (Pb), (Sb) and SbSn phases exhibit conspicuous solute trapping effect during rapid solidification, which results in the remarkable extension of solute solubility.

  1. Retention of As and Sb in ombrotrophic peat bogs: records of As, Sb, and Pb deposition at four Scottish sites.

    PubMed

    Cloy, Joanna M; Farmer, John G; Graham, Margaret C; MacKenzie, Angus B

    2009-03-15

    Possible postdepositional As migration in ombrotrophic peat bogs was investigated by comparing depth profiles of As with those of Sb and Pb, two elements considered to be essentially immobile in peat, and those of redox-sensitive, potentially mobile nutrient elements such as Mn, Fe, P, and S in 210Pb-dated cores from four Scottish bogs. Concentration profiles of As were similar to those of Sb and Pb rather than these other elements, indicating that As is bound strongly to organic matter and is relatively immobile in ombrotrophic peat. Historical records of atmospheric anthropogenic As, Sb, and Pb deposition during the industrial and postindustrial periods were derived, site-specific maxima (up to 1.55, 1.33, and 45 mg m(-2) y(-1), respectively) occurring between the late 1890s and 1960s, reflecting emissions from diverse sources such as mining and smelting, coal combustion, and also, in the case of Pb, exhaust emissions from the use of leaded gasoline. Since the mid-1980s, fluxes of Pb decreased (4-7 fold) more rapidly than those of As and Sb (2-3 fold), attributable to both the gradual elimination of leaded gasoline and recent new sources of the latter elements. Relative trends in derived anthropogenic As, Sb, and Pb deposition largely agreed with other Scottish peat and moss archive records, direct measurements of deposition, and UK emissions, i.e., four different types of data source. PMID:19368168

  2. Retention of As and Sb in ombrotrophic peat bogs: records of As, Sb, and Pb deposition at four Scottish sites

    SciTech Connect

    Joanna M. Cloy; John G. Farmer; Margaret C. Graham; Angus B. MacKenzie

    2009-03-15

    Possible postdepositional As migration in ombrotrophic peat bogs was investigated by comparing depth profiles of As with those of Sb and Pb, two elements considered to be essentially immobile in peat, and those of redox-sensitive, potentially mobile nutrient elements such as Mn, Fe, P, and S in {sup 210}Pb-dated cores from four Scottish bogs. Concentration profiles of As were similar to those of Sb and Pb rather than these other elements, indicating that As is bound strongly to organic matter and is relatively immobile in ombrotrophic peat. Historical records of atmospheric anthropogenic As, Sb, and Pb deposition during the industrial and postindustrial periods were derived, site-specific maxima (up to 1.55, 1.33, and 45 mg m{sup -2} y{sup -1}, respectively) occurring between the late 1890s and 1960s, reflecting emissions from diverse sources such as mining and smelting, coal combustion, and also, in the case of Pb, exhaust emissions from the use of leaded gasoline. Since the mid-1980s, fluxes of Pb decreased (4-7 fold) more rapidly than those of As and Sb (2-3 fold), attributable to both the gradual elimination of leaded gasoline and recent new sources of the latter elements. Relative trends in derived anthropogenic As, Sb, and Pb deposition largely agreed with other Scottish peat and moss archive records, direct measurements of deposition, and UK emissions, i.e., four different types of data source. 36 refs., 3 figs., 1 tab.

  3. Diverse lattice dynamics in ternary Cu-Sb-Se compounds

    PubMed Central

    Qiu, Wujie; Wu, Lihua; Ke, Xuezhi; Yang, Jihui; Zhang, Wenqing

    2015-01-01

    Searching and designing materials with extremely low lattice thermal conductivity (LTC) has attracted considerable attention in material sciences. Here we systematically demonstrate the diverse lattice dynamics of the ternary Cu-Sb-Se compounds due to the different chemical-bond environments. For Cu3SbSe4 and CuSbSe2, the chemical bond strength is nearly equally distributed in crystalline bulk, and all the atoms are constrained to be around their equilibrium positions. Their thermal transport behaviors are well interpreted by the perturbative phonon-phonon interactions. While for Cu3SbSe3 with obvious chemical-bond hierarchy, one type of atoms is weakly bonded with surrounding atoms, which leads the structure to the part-crystalline state. The part-crystalline state makes a great contribution to the reduction of thermal conductivity that can only be effectively described by including a rattling-like scattering process in addition to the perturbative method. Current results may inspire new approaches to designing materials with low lattice thermal conductivities for high-performance thermoelectric conversion and thermal barrier coatings. PMID:26328765

  4. Diverse lattice dynamics in ternary Cu-Sb-Se compounds

    NASA Astrophysics Data System (ADS)

    Qiu, Wujie; Wu, Lihua; Ke, Xuezhi; Yang, Jihui; Zhang, Wenqing

    2015-09-01

    Searching and designing materials with extremely low lattice thermal conductivity (LTC) has attracted considerable attention in material sciences. Here we systematically demonstrate the diverse lattice dynamics of the ternary Cu-Sb-Se compounds due to the different chemical-bond environments. For Cu3SbSe4 and CuSbSe2, the chemical bond strength is nearly equally distributed in crystalline bulk, and all the atoms are constrained to be around their equilibrium positions. Their thermal transport behaviors are well interpreted by the perturbative phonon-phonon interactions. While for Cu3SbSe3 with obvious chemical-bond hierarchy, one type of atoms is weakly bonded with surrounding atoms, which leads the structure to the part-crystalline state. The part-crystalline state makes a great contribution to the reduction of thermal conductivity that can only be effectively described by including a rattling-like scattering process in addition to the perturbative method. Current results may inspire new approaches to designing materials with low lattice thermal conductivities for high-performance thermoelectric conversion and thermal barrier coatings.

  5. Yield strength of Cu and an engineered material of Cu with 1% Pb

    NASA Astrophysics Data System (ADS)

    Buttler, William; Gray, George, III; Fensin, Saryu; Grover, Mike; Stevens, Gerald; Stone, Joseph; Turley, William

    2015-06-01

    To study the effects of engineered elastic-plastic yield on the mass-ejection from shocked materials we fielded explosively driven Cu and CuPb experiments. The Cu and CuPb experiments fielded fully annealed disks in contact with PBX 9501; the CuPb was extruded with 1% Pb that aggregates at the Cu grain boundaries. The elastic-plastic yield strength is explored as a difference of ejecta production of CuPb versus Cu, where the ejecta production of solid materials ties directly to the surface perturbation geometries of wavelengths (fixed at 65 μm) and amplitudes (which were varied). We observed that the Cu performs as expected, with ejecta turning on at the previously observed yield threshold, but the CuPb ejects mass in much larger quantities, at much lower wavenumber (k = 2 π/ λ) amplitude (h) products (kh), implying a reduced elastic-plastic yield stress of the engineered material, CuPb.

  6. Growth of tertiary dendritic arms during the transient directional solidification of hypoeutectic Pb-Sb alloys

    NASA Astrophysics Data System (ADS)

    Freitas, Emmanuelle S.; Rosa, Daniel M.; Garcia, Amauri; Spinelli, José E.

    2011-12-01

    Despite the importance of a complete characterization of dendritic patterns in castings, the availability of studies on the development of tertiary dendrite arms is scarce in the literature. In the present study, the tip cooling rate, local solidification time, primary and tertiary dendrite arm spacings have been determined in Pb-Sb alloys castings directionally solidified under unsteady-state heat flow conditions. The alloys compositions experimentally examined are widely used in the as-cast condition for the manufacture of positive and negative grids of lead-acid batteries. The initial growth of tertiary dendritic arms from the secondary branches was found to occur only for a Pb-3.5 wt% Sb alloy at cooling rates in the range 0.4-0.2 K/s, with no evidence of this spacing pattern for Pb-Sb alloys having lower solute content. Tertiary dendritic branches have been observed along the entire casting lengths for alloys of the Pb-Sb hypoeutectic range having compositions higher than 4.0 wt% Sb. It is shown that a power function experimental law with a characteristic -0.55 exponent is able to characterize the tertiary spacing evolution with the solidification cooling rate for alloys compositions ≥4.0 wt% Sb. The only exception was the Pb-3.5 wt% Sb alloy for which λ 3 exhibited significant lower values when compared with the experimental values obtained for the other Pb-Sb alloys for a same solidification cooling rate.

  7. Thermal Processing Effects on Microstructure and Composition of Cu3SbSe3

    SciTech Connect

    Majsztrik, Paul W; Kirkham, Melanie J; Garcia Negron, Valerie; Lara-Curzio, Edgar; Skoug, Eric; Morelli, Donald

    2013-01-01

    We report on the effects of thermal processing on the microstructure and composition of a system with overall stoichiometry of 3Cu:1Sb:3Se with the aim of producing single-phase Cu3SbSe3. It was found that slowly cooling from the melt produced a multiphase material consisting of Cu2Se and CuSbSe2, but devoid of Cu3SbSe3. Cooling rapidly from the melt resulted in three-phase microstructures consisting of Cu2Se, CuSbSe2, and Cu3SbSe3. Subsequent annealing of the three-phase material between 325 C and 400 C shifted composition towards nearly pure Cu3SbSe3, the target compound of this work. The kinetics of the transformation into Cu3SbSe3 is successfully described using a modified Avrami model, which suggests that diffusion is the rate-controlling step. Values of Young s modulus and hardness, obtained by nanoindentation, are reported for Cu2Se, CuSbSe2, and Cu3SbSe3.

  8. Sb/Cu2Sb-TiC-C Composite Anode for High-Performance Sodium-Ion Batteries.

    PubMed

    Chae, Seung Chul; Hur, Jaehyun; Kim, Il Tae

    2016-02-01

    A novel nanostructure consisting of copper-antimony alloy (Cu2Sb) particles dispersed in a conductive hybrid matrix of titanium carbide (TiC) and carbon (C) has been developed by high energy mechanical milling (HEMM) and explored for use as an anode in sodium-ion batteries. By controlling the molar ratio of Cu and Sb, Cu2Sb and Sb are able to co-exist in a matrix. The (Sb)/Cu2Sb-TiC-C samples have been characterized by X-ray diffraction and by high-resolution transmission electron microscopy. Specifically, the Cu2Sb-TiC-C composite anode demonstrates better cyclic performance as well as better rate-capability compared to Sb/Cu2Sb-TiC-C. Addition- ally, the introduction of the fluoroethylene carbonate (FEC) additive into the electrolyte leads to improved electrochemical performance even at high-rate current densities, when compared to the electrodes without the FEC additive, owing to the formation of a stable and thin SEI layer. PMID:27433694

  9. High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb

    NASA Astrophysics Data System (ADS)

    Sirohi, Anshu; Singh, Chandan K.; Thakur, Gohil S.; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Haque, Zeba; Gupta, L. C.; Kabir, Mukul; Ganguli, Ashok K.; Sheet, Goutam

    2016-06-01

    CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (˜47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.

  10. Dendritic solidification of undercooled Cu-20%Pb hypomonotectic alloy

    SciTech Connect

    Dong, C.; Wei, B.

    1996-05-15

    The Cu-Pb monotectic system is the basis of an important category of wear-resistant materials especially bearing alloys. Its industrially interesting composition ranges from 10 to 50%Pb. In order to produce aligned composites or homogeneous dispersions, extensive research has been performed to investigate the solidification mechanism of Cu-Pb monotectic alloys under directional solidification or microgravity conditions. The preliminary nature of the current space experiments on Cu-Pb monotectic solidification excludes the possibility to draw any really definite conclusions about the influences of microgravity. In contrast, so far still little has been known about the undercooling behavior and rapid solidification kinetics of Cu-Pb monotectic alloys. The objective of the present work is to undercool bulk samples of Cu-Pb alloys to a significant extent and investigate their subsequent rapid solidification process. and this paper reports the related results obtained for Cu-20%Pb hypomonotectic alloy.

  11. Study on Exploration of Azeotropic Point of Pb-Sb Alloys by Vacuum Distillation and Ab Initio Molecular Dynamic Simulation

    NASA Astrophysics Data System (ADS)

    Song, Bingyi; Jiang, Wenlong; Yang, Bin; Chen, Xiumin; Xu, Baoqiang; Kong, Lingxin; Liu, Dachun; Dai, Yongnian

    2016-07-01

    The possibility of the separation of Pb-Sb alloys by vacuum distillation was investigated theoretically. The results show that Pb and Sb can be separated by vacuum distillation. However, the experimental results show that vacuum distillation technique does not provide clear separation. According to the literature, Pb-Sb alloys belong to azeotropic compounds under some certain temperature; the experiment and computer simulation were carried out based on the exceptional condition so as to analyze the reason from the experiment and microstructure of Pb-Sb alloys perspective. The separation of Pb-Sb alloys by vacuum distillation was experimentally carried out to probe the azeotropic point. Also, the functions, such as partial radial distributions functions, the structure factor, mean square displacement, and the density of state, were calculated by ab-initio molecular dynamics for the representation of the structure and properties of Pb-Sb alloys with different composition of Sb. The experimental results indicate that there exists common volatilization for Pb-Sb alloys when Sb content is 16.5 wt pct. On the other hand, the calculation results show that there is an intense interaction between Pb and Sb when Sb content is 22 wt pct, which supports the experimental results although Sb content is slightly deviation.

  12. Insight into the mechanism of Sb promoted Cu(In,Ga)Se{sub 2} formation

    SciTech Connect

    Xiang, Yong Zhang, Xiaokun; Zhang, Shu

    2013-08-15

    Sb-doping has been demonstrated to be a new approach to promote Cu(In,Ga)Se{sub 2} (CIGS) thin film formation. To study the mechanism of Sb-promoted CIGS formation, we investigated the influence of Sb on the evolution of the critical intermediate Cu–Se phases, and found that Cu{sub 3}SbSe{sub 3} species was formed. Phase change of the as-prepared Cu–Se compounds at elevated temperature was determined using the differential scanning calorimetry analysis. For samples containing Sb, the melting decomposition occurred at 507.1 °C, along with aggregation of nanocrystals into a bulk, while the morphology of the sample without Sb barely changed after heating. This result suggests that the mobile Cu{sub 3}SbSe{sub 3} is likely the key intermediate responsible for Sb-promoted CIGS formation. Furthermore, we extended the scope of Sb-doping approach to solvothermal synthesis and CIGS nanocrystals were synthesized with significantly promoted kinetics in the presence of Sb. Based on these results, we propose the mechanism of Sb promoted CIGS formation. - Graphical abstract: Cu{sub 3}SbSe{sub 3} mobile phase is likely the key species to promote the formation of Cu(In,Ga)Se{sub 2}, and significantly promoting effect by Sb is also found in the synthesis of Cu(In,Ga)Se{sub 2} nanocrystals. Highlights: • In the presence of Sb, Cu{sub 3}SbSe{sub 3} is formed while synthesizing the essential intermediate Cu–Se compounds for Cu(In,Ga)Se{sub 2} materials. • Cu{sub 3}SbSe{sub 3} shows high mobility at elevated temperature. • Cu{sub 3}SbSe{sub 3} mobile phase is likely the key species to improve Cu(In,Ga)Se{sub 2} thin film formation. • A synthesis methodology is developed to produce Cu(In,Ga)Se{sub 2} nanocrystals with significantly promoted reaction kinetics.

  13. Quick Fabrication and Thermoelectric Properties of Cu12Sb4S13 Tetrahedrite

    NASA Astrophysics Data System (ADS)

    Wang, Juyi; Gu, Ming; Bao, Yefeng; Li, Xiaoya; Chen, Lidong

    2016-04-01

    Tetrahedrites, comprised mainly of earth-abundant and environment-friendly elements, copper and sulfur, may pave the way to many new and low-cost thermoelectric energy generation opportunities. However, the preparation of tetrahedrites is time- and energy-consuming. In this paper, we study the melting process and the effect of the annealing time on the microstructure and thermoelectric properties of the Cu12Sb4S13 tetrahedrite, in an effort to shorten the synthesis (melting and annealing) time. Our results show that the Cu12Sb4S13 tetrahedrite phase forms in the melt during cooling. Shortening the melting time does not affect the formation of Cu12Sb4S13. The cooled ingot consists of the principal phase of Cu12Sb4S13 and two secondary phases, Cu3SbS4 and CuSbS2. It is found that prolonged annealing cannot eliminate the impurity phases in Cu12Sb4S13 tetrahedrite, has a small effect on the electrical resistivity, and a negligible effect on the Seebeck coefficient and the thermal conductivity of the tetrahedrite. All our samples have a ZT above 0.47 at 600 K and the maximum ZT obtained was 0.52 when the sample was annealed for 1 day. Based on our experimental results, the time for preparing the Cu12Sb4S13 tetrahedrite can be considerably shortened.

  14. First-principles Study of Lattice Thermal Conductivity of Cu3SbS4andCu3SbSe4

    NASA Astrophysics Data System (ADS)

    Xia, Yi; Zhou, Fei; Nielson, Weston; Ozolins, Vidvuds

    2015-03-01

    Linearized self-consistent Boltzmann transport equation (BTE), utilizing interatomic force constants (IFCs) obtained via compressive sensing lattice dynamics (CSLD), is used to study the lattice thermal conductivity (κl) of Cu3SbS4, Cu3SbSe4 and their solid solutions. With these IFCs we obtain bulk lattice thermal conductivity in good agreement with experimental measurements. We also compare Cu3SbS4andCu3SbSe4 with respect to Grüneisen parameter, group velocity, phonon lifetime, mean free path and cumulative κl. All the analysis indicates that (1) slightly larger group velocity and lifetime of acoustic modes found in Cu3SbS4 lead to larger κl compared with Cu3SbSe4 over the whole temperature range. Contributions from optical modes to κl for both compounds are about 25% at temperature higher than 300K. This large portion of κl can not be neglected if one aims to predict accurate κl; (2) Nanostructures with length less than 10nm can effectively reduce κl by about 80% for both of the compounds; (3) solid solution of two compounds can effectively reduce κl as much as 40% at room temperature.

  15. Atomistic Structure and Nucleation of Nanoprecipitates in Thermoelectric PbTe- AgSbTe Composite

    SciTech Connect

    Ke, Xuezhi; Chen, Changfeng; Yang, Jihui; Wu, Lijun; Zhou, Juan; Li, Qiang; Zhu, Yimei; Kent, Paul R

    2009-01-01

    Many recent advances in thermoelectric (TE) materials are attributed to their nanoscale constituents. Determination of the nanocomposite structures has represented a major experimental and computational challenge and eluded previous attempts. Here we present the first atomically resolved structures of high performance TE material PbTe-AgSbTe2 by transmission electron microscopy imaging and density functional theory calculations. The results establish an accurate structural characterization for PbTe-AgSbTe2 and identify the interplay of electric dipolar interactions and strain fields as the driving mechanism for nanoprecipitate nucleation and aggregation.

  16. Effects of Cu5Zn3 addition on the thermoelectric properties of Zn4Sb3

    NASA Astrophysics Data System (ADS)

    Cui, J. L.; Fu, H.; Mao, L. D.; Chen, D. Y.; Liu, X. L.

    2009-07-01

    The structures and thermoelectric properties of mCu5Zn3ṡnZn4Sb3 with multiphase coexistence are reported. Rietveld analysis reveals that at least 92.3% wt % β-Zn4Sb3 phase can be obtained with only small quantities of ZnSb and Cu5Zn8 phases precipitated after proper Cu5Zn3 addition. Measurements indicate that although the β-Zn4Sb3 phase plays a determining role in controlling the transport properties involving the Seebeck coefficient, electrical conductivity, and thermal conductivity, the impurity phases Cu5Zn8 and ZnSb with a crooked riverlike and intertwined tree stump morphologies, respectively, are still of great significance to tune the thermoelectric performance. The highest ZT value of 0.84 can be obtained for the alloy mCu5Zn3ṡnZn4Sb3 (m /n=1/200) at 631 K, approximately 1.8 times that of undoped β-Zn4Sb3, proving that a good combination between the transports of carriers and phonons can be achieved if a proper dopant is introduced in the Zn4Sb3 matrix.

  17. Immobilisation of Cu, Pb and Zn in Scrap Metal Yard Soil Using Selected Waste Materials.

    PubMed

    Kamari, A; Putra, W P; Yusoff, S N M; Ishak, C F; Hashim, N; Mohamed, A; Isa, I M; Bakar, S A

    2015-12-01

    Immobilisation of heavy metals in a 30-year old active scrap metal yard soil using three waste materials, namely coconut tree sawdust (CTS), sugarcane bagasse (SB) and eggshell (ES) was investigated. The contaminated soil was amended with amendments at application rates of 0 %, 1 % and 3 % (w/w). The effects of amendments on metal accumulation in water spinach (Ipomoea aquatica) and soil metal bioavailability were studied in a pot experiment. All amendments increased biomass yield and reduced metal accumulation in the plant shoots. The bioconcentration factor and translocation factor values of the metals were in the order of Zn > Cu > Pb. The addition of ES, an alternative source of calcium carbonate (CaCO3), has significantly increased soil pH and resulted in marked reduction in soil metal bioavailability. Therefore, CTS, SB and ES are promising low-cost immobilising agents to restore metal contaminated land. PMID:26395356

  18. Cell/dendrite transition and electrochemical corrosion of Pb-Sb alloys for lead-acid battery applications

    NASA Astrophysics Data System (ADS)

    Osório, Wislei R.; Rosa, Daniel M.; Peixoto, Leandro C.; Garcia, Amauri

    2011-08-01

    The aim of this article is focused on a comparative experimental study of the electrochemical feature of as-cast Pb-2.2 wt.% Sb alloy with cellular/dendritic transition for applications in the manufacturing of lead-acid battery parts. A water-cooled unidirectional solidification system is used to obtain the alloy samples. Electrochemical impedance spectroscopy (EIS) plots, potentiodynamic polarization curves and equivalent circuit analysis are used to evaluate corrosion resistance in a 0.5 M H2SO4 solution at 25 °C. The cellular Pb-2.2 wt.% Sb alloy is found to have a current density which is of about 3 times lower than that of the dendritic Pb-2.2 wt.% Sb alloy. The Pb-2.2 wt.% Sb alloy has lower current density than both the Pb-1 wt.% Sb and the Pb-6.6 wt.% Sb alloys evidencing its potential for application as positive grid material in lead-acid batteries. It is also verified that a conventional casting with low cooling rate of about 0.6 °C s-1 produces coarser cellular spacings which is more appropriate for the manufacturing of the Pb-2.2 wt.% Sb alloys grids due to its corresponding electrochemical behavior.

  19. Partial Cu occupancy in uranium copper diantimonide, UCu0.60(4))Sb2.

    PubMed

    Ringe, Emilie; Ibers, James A

    2008-08-01

    The title compound, UCu(0.60(4))Sb(2), crystallizes in the tetragonal space group P4/nmm. The U atom and one independent Sb atom have 4mm site symmetry, whereas the Cu atom and the other Sb atom have \\overline{4}2m site symmetry. Zigzag USb sheets stack perpendicular to the c axis. These sheets are separated by square-planar nets of Sb atoms and Cu atoms. The length of the a axis for UCu(x)Sb(2) is invariant to x, whereas there is a linear relationship between Cu occupancy and the length of the c axis (following Vegard's Law) that holds for x between 0 and 1. This is explained in terms of the crystal structure. PMID:18682633

  20. Probing the mechanism of sodium ion insertion into copper antimony Cu2Sb anodes

    DOE PAGESBeta

    Baggetto, Loic; Carroll, Kyler J.; Hah, Hien -Yoong; Johnson, Charles E.; Mullins, David R.; Unocic, Raymond R.; Johnson, Jacqueline A.; Meng, Ying Shirley; Veith, Gabriel M.

    2014-03-25

    Cycling Cu2Sb films with fluoroethylene carbonate additive drastically improves the capacity retention of the electrode compared to cycling in pure PC with about 250 mAh g-1 retained capacity for about two hundred cycles. TEM photographs reveal that the pristine films are formed of nanoparticles of 5-20 nm diameters. XRD results highlight that during the first discharge the reaction leads to the formation of Na3Sb via an intermediate amorphous phase. During charge, Na3Sb crystallites convert into an amorphous phase, which eventually crystallizes into Cu2Sb at full charge, indicating a high degree of structural reversibility. The subsequent discharge is marked by amore » new plateau around 0.5 V at low Na/Sb content which does not correspond to the formation of a crystalline phase. XAS data show that the fully discharged electrode material has interatomic distances matching those expected for the coexistence of Cu and Na3Sb nanodomains. At 1 V charge, the structure somewhat differs from that of Cu2Sb whereas at 2 V charge, when all Na is removed, the structure is significantly closer to that of the starting material. 121Sb Mössbauer spectroscopy isomer shifts of Cu2Sb powder (-9.67 mm s-1) and thin films (-9.65 mm s-1) are reported for the first time, and agree with the value predicted theoretically. At full discharge, an isomer shift (-8.10 mm s-1) rather close to that of a Na3Sb reference powder (-8.00 mm s-1) is measured, in agreement with the formation of Na3Sb domains evidenced by XRD and XAS data. As a result, the isomer shift at 1 V charge (-9.29 mm s-1) is close to that of the pristine material and the higher value is in agreement with the lack of full desodiation at 1 V.« less

  1. A model for the composition modifications in the Cu-Sb-O system

    SciTech Connect

    Stan, M.

    1997-05-01

    THE SN-SB-CU-O SYSTEM HAS BEEN EXTENSIVELY STUDIED BUT SYSTEMATIC PHASE EQUILIBRIUM STUDIES HAVE NOT BEEN APPROACHED. THE SYSTEM CONTAINS USEFUL CERAMICS WITH SPECIFIC ELECTRICAL AND MAGNETIC PROPERTIES, EMPLOYED AS SENSORS, ELECTRODES AND CATALYSTS. AS A PRELIMINARY STEP TO THE PHASE DIAGRAM CALCULATION, THE PAPER AIMS TO PRESENT A MODEL FOR THE COMPOSITION MODIFICATIONS IN THE CU-SB-O SYSTEM, WHICH IS THE MOST COMPLEX OF ALL SUBSYSTEMS. EXOTHERMIC EFFECTS ALONG WITH MASS INCREASES CAN BE OBSERVED IN DTA/GA CURVES, WERE ASSIGNED, FOR ALL SAMPLES, TO SB2O3 AND SB2O4 OXIDATION AND TO CUSB2O6 FORMATION: (1) APPROX. EQUAL 500 DIG C SB2O3 + 1/2 O2 DOUBLE RIGHT ARROW SB2O4; (2) {gt} 750 DIG C SB2O4 + CUO + 1/2 O2 DOUBLE RIGHT ARROW CUSB2O6. FOR THE SAMPLES HAVING CUO IN EXCESS, THE REDUCTION OF CUO TO CUO AND THE FORMATION OF THE CU4SBO4.5 COMPOUND SIMULTANEOUSLY OCCUR: {gt} 950 dig C CUSB2O6 + 7CuO double right arrow (1-r) CUSB2O6+7(1-r)cow+ 2rCu4SbO4.5 + 2rO2 where rEpsilon (0, 1) is the fraction of CUSB2O6 that transforms into Cu4SbO4.5. All the experimental evidences show that the Equations (1), (2) and (3) are good descriptions of the transformations that occurs in the CuO-Sb2O3 system along with the temperature. If the reactions are considered as completed, including a=1 in IQ. (3), then the quantity of oxygen that is gained or lost can be calculated for each sample. It is important to note that Equations (2) and (3) should be carefully solved because of the excess quantities of cow or SB2O4 that can be found in some samples. The calculated values of mass variation are in a good agreement with those obtained from the experimental GT diagrams. The atomic fractions of Cu, Sb and Awe content change in the system and they can be also calculated. The model assumes that at room temperature the compositions lay on the CuO-Sb2O3 line as shown in Fig. 1.

  2. Antiferromagnetism in EuCu2As2 and EuCu1.82Sb2 single crystals

    DOE PAGESBeta

    Anand, V. K.; Johnston, D. C.

    2015-05-07

    Single crystals of EuCu2As2 and EuCu2Sb2 were grown from CuAs and CuSb self-flux, respectively. The crystallographic, magnetic, thermal, and electronic transport properties of the single crystals were investigated by room-temperature x-ray diffraction (XRD), magnetic susceptibility χ versus temperature T, isothermal magnetization M versus magnetic field H, specific heat Cp(T), and electrical resistivity ρ(T) measurements. EuCu2As2 crystallizes in the body-centered tetragonal ThCr2Si2-type structure (space group I4/mmm), whereas EuCu2Sb2 crystallizes in the related primitive tetragonal CaBe2Ge2-type structure (space group P4/nmm). The energy-dispersive x-ray spectroscopy and XRD data for the EuCu2Sb2 crystals showed the presence of vacancies on the Cu sites, yielding themore » actual composition EuCu1.82Sb2. The ρ(T) and Cp(T) data reveal metallic character for both EuCu2As2 and EuCu1.82Sb2. Antiferromagnetic (AFM) ordering is indicated from the χ(T),Cp(T), and ρ(T) data for both EuCu2As2 (TN = 17.5 K) and EuCu1.82Sb2 (TN = 5.1 K). In EuCu1.82Sb2, the ordered-state χ(T) and M(H) data suggest either a collinear A-type AFM ordering of Eu+2 spins S = 7/2 or a planar noncollinear AFM structure, with the ordered moments oriented in the tetragonal ab plane in either case. This ordered-moment orientation for the A-type AFM is consistent with calculations with magnetic dipole interactions. As a result, the anisotropic χ(T) and isothermal M(H) data for EuCu2As2, also containing Eu+2 spins S = 7/2, strongly deviate from the predictions of molecular field theory for collinear AFM ordering and the AFM structure appears to be both noncollinear and noncoplanar.« less

  3. Antiferromagnetism in EuCu2As2 and EuCu1.82Sb2 single crystals

    NASA Astrophysics Data System (ADS)

    Anand, V. K.; Johnston, D. C.

    2015-05-01

    Single crystals of EuCu2As2 and EuCu2Sb2 were grown from CuAs and CuSb self-flux, respectively. The crystallographic, magnetic, thermal, and electronic transport properties of the single crystals were investigated by room-temperature x-ray diffraction (XRD), magnetic susceptibility χ versus temperature T , isothermal magnetization M versus magnetic field H , specific heat Cp(T ) , and electrical resistivity ρ (T ) measurements. EuCu2As2 crystallizes in the body-centered tetragonal ThCr2Si2 -type structure (space group I 4 /m m m ), whereas EuCu2Sb2 crystallizes in the related primitive tetragonal CaBe2Ge2 -type structure (space group P 4 /n m m ). The energy-dispersive x-ray spectroscopy and XRD data for the EuCu2Sb2 crystals showed the presence of vacancies on the Cu sites, yielding the actual composition EuCu1.82Sb2 . The ρ (T ) and Cp(T ) data reveal metallic character for both EuCu2As2 and EuCu1.82Sb2 . Antiferromagnetic (AFM) ordering is indicated from the χ (T ) ,Cp(T ) , and ρ (T ) data for both EuCu2As2 (TN=17.5 K) and EuCu1.82Sb2 (TN=5.1 K). In EuCu1.82Sb2 , the ordered-state χ (T ) and M (H ) data suggest either a collinear A-type AFM ordering of Eu+2 spins S =7/2 or a planar noncollinear AFM structure, with the ordered moments oriented in the tetragonal a b plane in either case. This ordered-moment orientation for the A-type AFM is consistent with calculations with magnetic dipole interactions. The anisotropic χ (T ) and isothermal M (H ) data for EuCu2As2 , also containing Eu+2 spins S =7/2 , strongly deviate from the predictions of molecular field theory for collinear AFM ordering and the AFM structure appears to be both noncollinear and noncoplanar.

  4. Surface Morphology Changes During Pb Deposition on Cu(100): Evidence for Surface Alloyed Cu(100)-c(2x2) Pb

    SciTech Connect

    PLASS,RICHARD A.; KELLOGG,GARY LEE

    2000-07-13

    Using Low Energy Electron Microscopy (LEEM), the authors have followed Cu(100) surface morphology changes during Pb deposition at different temperatures. Surface steps advance and 2-D islands nucleate and grow as deposited Pb first alloys, and then dealloys, on a 125 C Cu(100)surface. From LEEM images, they determine how much Cu is being displaced at each stage and find that the amount of material added to the top layer for a complete Pb/Cu(100) c(4x4) reconstruction (a surface alloy) is consistent with the expected c(4x4) Cu content of 0.5 monolayer. However, as the surface changes to the Pb/Cu(100) c(2x2) overlayer, they find that the displaced material from surface dealloying, 0.22ML, is more than a factor of two lower than expected based on a pure Pb c(2x2) overlayer. Further, they find that in the 70 to 130 C range the amount of Cu remaining in c(2x2) increases with increasing substrate temperature during the deposition, showing that surface Cu is alloyed with Pb in the c(2x2) structure at these temperatures. When holding the sample at 125 C, the transformation from the c(2x2) structure to the higher coverage c(5{radical}2 x{radical}2)R45{degree} overlayer structure displaces more Cu, confirming the c(2x2) surface alloy model. They also find the c(2x2) surface has characteristically square 2-D islands with step edges parallel to the (100) type crystallographic directions, whereas the c(5{radical}2 x{radical}2)R45{degree} structure has line-like features which run parallel to the dislocation double rows of this surface's atomic structure and which expand into 2-D islands upon coarsening.

  5. An impurity intermediate band due to Pb doping induced promising thermoelectric performance of Ca5In2Sb6.

    PubMed

    Feng, Zhenzhen; Wang, Yuanxu; Yan, Yuli; Zhang, Guangbiao; Yang, Jueming; Zhang, Jihua; Wang, Chao

    2015-06-21

    Band engineering is one of the effective approaches for designing ideal thermoelectric materials. Introducing an intermediate band in the band gap of semiconducting thermoelectric compounds may largely increase the carrier concentration and improve the electrical conductivity of these compounds. We test this hypothesis by Pb doping in Zintl Ca5In2Sb6. In the current work, we have systematically investigated the electronic structure and thermoelectric performances of substitutional doping with Pb on In sites at a doping level of 5% (0.2 e per cell) for Ca5In2Sb6 by using density functional theory combined with semi-classical Boltzmann theory. It is found that in contrast to Zn doping, Pb doping introduces a partially filled intermediate band in the band gap of Ca5In2Sb6, which originates from the Pb s states by weakly hybridizing with the Sb p states. Such an intermediate band dramatically increases the electrical conductivity of Ca5In2Sb6 and has little detrimental effect on its Seebeck coefficient, which may increase its thermoelectric figure of merit, ZT. Interestingly, a maximum ZT value of 2.46 may be achieved at 900 K for crystalline Pb-doped Ca5In2Sb6 when the carrier concentration is optimized. Therefore, Pb-doped Ca5In2Sb6 may be a promising thermoelectric material. PMID:25991513

  6. Impact of Lone-Pair Electrons on Thermal Conductivity in CuSbS2 Compound

    NASA Astrophysics Data System (ADS)

    Du, Baoli; Zhang, Ruizhi; Chen, Kan; Reece, Michael; Material research institute Team

    Compounds with intrinsically low lattice thermal conductivity are of practical importance for thermoelectric energy conversion. Recent studies suggest that s2 lone pair orbital electrons are a key contributing factor to the anomalously low lattice thermal conductivity of chalcogenide compounds that contain a nominally trivalent group VA element. CuSbS2 has an orthorhombic structure with space group Pnma. The pyramidal SbS5 units are separated by CuS4 tetrahedron so that the base of the square pyramidal units are aligned to face one another, thus directing the Sb lone pair electron density into the void separating the SbS5 units. Different from tetrahedrite, all the Cu atoms are bonded in the CuS4 tetrahedron. So, it has a perfect structure to study the influence of electron lone pair on thermal conductivity without the impact from trigonal coordinated Cu. In this work, the trivalent transition metal atom Fe and IIIA atom Ga without lone-pair electrons were chosen to substitute Sb in CuSbS2. The changes in the bonding environment by foreign atoms and their influences on the thermal properties have been studied and correlated. Marie Curie International Incoming Fellowship of the European Community Human Potential Program under Contract No. PIIF-GA-2013-622847.

  7. The antimony-group 11 chemical bond: Dissociation energies of the diatomic molecules CuSb, AgSb, and AuSb

    SciTech Connect

    Carta, V.; Ciccioli, A. E-mail: andrea.ciccioli@uniroma1.it; Gigli, G. E-mail: andrea.ciccioli@uniroma1.it

    2014-02-14

    The intermetallic molecules CuSb, AgSb, and AuSb were identified in the effusive molecular beam produced at high temperature under equilibrium conditions in a double-cell-like Knudsen source. Several gaseous equilibria involving these species were studied by mass spectrometry as a function of temperature in the overall range 1349–1822 K, and the strength of the chemical bond formed between antimony and the group 11 metals was for the first time measured deriving the following thermochemical dissociation energies (D{sub 0}{sup ∘}, kJ/mol): 186.7 ± 5.1 (CuSb), 156.3 ± 4.9 (AgSb), 241.3 ± 5.8 (AuSb). The three species were also investigated computationally at the coupled cluster level with single, double, and noniterative quasiperturbative triple excitations (CCSD(T)). The spectroscopic parameters were calculated from the potential energy curves and the dissociation energies were evaluated at the Complete Basis Set limit, resulting in an overall good agreement with experimental values. An approximate evaluation of the spin-orbit effect was also performed. CCSD(T) calculations were further extended to the corresponding group 11 arsenide species which are here studied for the first time and the following dissociation energies (D{sub 0}{sup ∘}, kJ/mol): 190 ± 10 (CuAs), 151 ± 10 (AgAs), 240 ± 15 (AuAs) are proposed. Taking advantage of the new experimental and computational information here presented, the bond energy trends along group 11 and 4th and 5th periods of the periodic table were analyzed and the bond energies of the diatomic species CuBi and AuBi, yet experimentally unobserved, were predicted on an empirical basis.

  8. (Mn 1-xPb x)Pb 10+ySb 12-yS 26-yCl 4+yO, a new oxy-chloro-sulfide with ˜2 nm-spaced (Mn,Pb)Cl 4 single chains within a waffle-type crystal structure

    NASA Astrophysics Data System (ADS)

    Doussier, Charlotte; Moëlo, Yves; Léone, Philippe; Meerschaut, Alain

    2007-08-01

    The new oxy-chloro-sulfide (Mn 1-xPb x)Pb 10+ySb 12-yS 26-yCl 4+yO ( x ∈ [0.2-0.3]; y ∈ [0.3-1.6]) was synthesized by dry way at 500-600 °C. A single crystal ˜Mn 0.7Pb 11.0Sb 11.3S 25.3Cl 4.7O indicates a monoclinic symmetry, space group C2 /m, with a = 37.480(8), b = 4.1178(8), c = 18.167(4) Å, β = 106.37(3)°, V = 2690.2(9) Å 3, Z = 2. Its crystal structure was determined by X-ray single crystal diffraction, with a final R = 5.11%. Modular analysis of the crystal structure reveals a "waffle" architecture, where complex rods with lozenge section delimitate an internal channel filled by a single chain of (Mn 0.7Pb 0.3)Cl 6 octahedra connected by opposite edges. Minimal inter-chain distances are close to 18 Å. The rod wall, two-atom thick, presents, in alternation with S atoms, Pb or (Pb,Sb) cations with prismatic coordination in the internal atom layer, while the external atom layer is constituted exclusively by Sb cations with dissymmetric square pyramidal coordination. A (Pb,Sb) 2S 2 fragment connects two successive rods along (2 0 1) to form a waffle-type palissadic layer. The unique O position, half filled, presents the same environment than the isolated O positions in the oxy-sulfide Pb 14Sb 30S 54O 5, or oxy-chloro-sulfides Pb 18Sb 20S 46Cl 2O and (Cu,Ag) 2Pb 21Sb 23S 55ClO. This compound belongs to a pseudo-homologous series of chalcogenides with waffle structure, ordered according to the size of their lozenge shape channel. Such a complex senary compound of the oxy-chloro-sulfide type illustrates the structural competition between three cations, on one hand, and, on the other hand, three anions. This compound is of special interest regarding the 1D distribution of magnetic Mn 2+ atoms at the ˜2 nm scale.

  9. Optoelectronic Investigation of Sb-Doped Cu(In, Ga)Se2

    SciTech Connect

    Mansfield, Lorelle M.; Kuciauskas, Darius; Dippo, Patricia; Li, Jian V.; Bowers, Karen; To, Bobby; DeHart, Clay; Ramanathan, Kannan

    2015-06-14

    Doping Cu(In,Ga)Se2 (CIGS) thin films with Sb can provide large grains at lower processing temperatures than are normally required. In this study, we incorporated Sb into the precursor of a two-step selenization process. We saw enhanced grain size and improved device performance compared to similarly processed CIGS films made without Sb. The optoelectronic properties of the Sb-doped CIGS films were examined with photoluminescence (PL) and admittance spectroscopy. These techniques allowed us to evaluate the origin of a lower-energy PL peak that is not typically seen in CIGS.

  10. The magnetic structure of EuCu2Sb2

    DOE PAGESBeta

    Ryan, D. H.; Cadogan, J. M.; Anand, V. K.; Johnston, D. C.; Flacau, R.

    2015-05-06

    Antiferromagnetic ordering of EuCu2Sb2 which forms in the tetragonal CaBe2Ge2-type structure (space group P4/nmm #129) has been studied using neutron powder diffraction and 151Eu Mössbauer spectroscopy. The room temperature 151Eu isomer shift of –12.8(1) mm/s shows the Eu to be divalent, while the 151Eu hyperfine magnetic field (Bhf) reaches 28.7(2) T at 2.1 K, indicating a full Eu2+ magnetic moment. Bhf(T) follows a smoothmore » $$S=\\frac{7}{2}$$ Brillouin function and yields an ordering temperature of 5.1(1) K. Refinement of the neutron diffraction data reveals a collinear A-type antiferromagnetic arrangement with the Eu moments perpendicular to the tetragonal c-axis. As a result, the refined Eu magnetic moment at 0.4 K is 7.08(15) μB which is the full free-ion moment expected for the Eu2+ ion with $$S=\\frac{7}{2}$$ and a spectroscopic splitting factor of g = 2.« less

  11. Cu2Sb thin film electrodes prepared by pulsed laser deposition f or lithium batteries

    SciTech Connect

    Song, Seung-Wan; Reade, Ronald P.; Cairns, Elton J.; Vaughey, Jack T.; Thackeray, Michael M.; Striebel, Kathryn A.

    2003-08-01

    Thin films of Cu2Sb, prepared on stainless steel and copper substrates with a pulsed laser deposition technique at room temperature, have been evaluated as electrodes in lithium cells. The electrodes operate by a lithium insertion/copper extrusion reaction mechanism, the reversibility of which is superior when copper substrates are used, particularly when electrochemical cycling is restricted to the voltage range 0.65-1.4 V vs. Li/Li+. The superior performance of Cu2Sb films on copper is attributed to the more active participation of the extruded copper in the functioning of the electrode. The continual and extensive extrusion of copper on cycling the cells leads to the isolation of Li3Sb particles and a consequent formation of Sb. Improved cycling stability of both types of electrodes was obtained when cells were cycled between 0.65 and 1.4 V. A low-capacity lithium-ion cell with Cu2Sb and LiNi0.8Co0.15Al0.05O2 electrodes, laminated from powders, shows excellent cycling stability over the voltage range 3.15 - 2.2 V, the potential difference corresponding to approximately 0.65-1.4 V for the Cu2Sb electrode vs. Li/Li+. Chemical self-discharge of lithiated Cu2Sb electrodes by reaction with the electrolyte was severe when cells were allowed to relax on open circuit after reaching a lower voltage limit of 0.1 V. The solid electrolyte interphase (SEI) layer formed on Cu2Sb electrodes after cells had been cycled between 1.4 and 0.65 V vs. Li/Li+ was characterized by Fourier-transform infrared spectroscopy; the SEI layer contributes to the large irreversible capacity loss on the initial cycle of these cells. The data contribute to a better understanding of the electrochemical behavior of intermetallic electrodes in rechargeable lithium batteries.

  12. New CuM 2/3Sb 1/3O 2 and AgM 2/3Sb 1/3O 2 compounds with the delafossite structure

    NASA Astrophysics Data System (ADS)

    Nagarajan, R.; Uma, S.; Jayaraj, M. K.; Tate, J.; Sleight, A. W.

    2002-05-01

    Several new compounds have been prepared with the delafossite structure: CuMn 2/3Sb 1/3O 2, CuCo 2/3Sb 1/3O 2, CuNi 2/3Sb 1/3O 2, CuZn 2/3Sb 1/3O 2, CuMg 2/3Sb 1/3O 2, AgNi 2/3Sb 1/3O 2, and AgZn 2/3Sb 1/3O 2. The structures of the CuM 2/3Sb 1/3O 2 compounds are generally based on 2H stacking along the c axis, and the M 2+ and Sb 5+ cations can be ordered or disordered. The structures of the AgM 2/3Sb 1/3O 2 compounds are based on 3R stacking along c with the M 2+ and Sb 5+ cations disordered. The structures of CuMn 2/3Sb 1/3O 2 (disordered) and CuMg 2/3Sb 1/3O 2 (ordered) were refined from single crystal X-ray diffraction data. Pellets and transparent thin films of CuNi 2/3Sb 1/3O 2 with 10% Sn doping for Sb showed p-type electronic conduction.

  13. Synthesis, crystal and electronic structures, and physical properties of caged ternary Cu-rich antimonide: BaCu(7.31(3))Sb5.

    PubMed

    Zheng, Wu-Zui; Wang, Peng; Wu, Li-Ming; Chen, Ling

    2010-08-16

    A new caged Cu-rich antimonide, BaCu(7.31(3))Sb(5), was obtained from a direct combination of the elements in a graphite crucible under a high vacuum by a solid state reaction, and the structure was determined by the single-crystal X-ray diffraction method to be hexagonal P6(3)/mmc (No.194), with a = 7.0154(4) A, c = 12.5423(14) A, V = 534.58(7) A(3), and Z = 2. BaCu(7.31(3))Sb(5) is the first antimonide member of the BaNi(9)P(5)-type barium copper pnictides with a Cu2 site occupancy of 43.7(9)%, and the structure building unit is a 30-vertex Cu(18)Sb(12) cage centered by a Ba atom. The Cu(18)Sb(12) cages form chains along the c axis by sharing the opposite hexagonal (Cu2)(3)(Sb2)(3) faces. Such a cage chain shares (Cu1)(2)(Sb1)(2) rhomboidal faces with six neighboring chains along the [100], [010], and [110] directions to generate a 3D condensed metallic network. The electronic structure calculations by CASTEP indicate the metallic nature, which matches well with the metallic electrical conductivity, small Seebeck coefficient, and Pauli paramagnetism. The calculated formation energies indicate that BaCu(7.5)Sb(5)[triple bond]Ba(2)Cu(15)Sb(10) with the Cu2 site half occupied is the energetically favorable stoichiometry compared with Ba(2)Cu(12)Sb(10) (empty Cu2 site) and Ba(2)Cu(18)Sb(10) (fully occupied Cu2 site). PMID:20690758

  14. Failure analysis of PB-1 (EBTS Be/Cu mockup)

    SciTech Connect

    Odegard, B.C. Jr.; Cadden, C.H.

    1996-11-01

    Failure analysis was done on PB-1 (series of Be tiles joined to Cu alloy) following a tile failure during a high heat flux experiment in EBTS (electron beam test system). This heat flux load simulated ambient conditions inside ITER; the Be tiles were bonded to the Cu alloy using low-temperature diffusion bonding, which is being considered for fabricating plasma facing components in ITER. Results showed differences between the EBTS failure and a failure during a room temperature tensile test. The latter occurred at the Cu-Be interface in an intermetallic phase formed by reaction of the two metals at the bonding temperature. Fracture strengths measured by these tests were over 300 MPa. The high heat flux specimens failed at the Cu-Cu diffusion bond. Fracture morphology in both cases was a mixed mode of dimple rupture and transgranular cleavage. Several explanations for this difference in failure mechanism are suggested.

  15. Physical preparation and optical properties of CuSbS2 nanocrystals by mechanical alloying process

    NASA Astrophysics Data System (ADS)

    Zhang, Huihui; Xu, Qishu; Tan, Guolong

    2016-08-01

    CuSbS2 nanocrystals have been synthesized through mechanical alloying Cu, Sb and S elemental powders for 40 hs. The optical spectrum of as-milled CuSbS2 nano-powders demonstrates a direct gap of 1.35 eV and an indirect gap of 0.36 eV, which are similar to that of silicon and reveals the evidence for the indirect semiconductor characterization of CuSbS2. Afterwards, CuSbS2 nanocrystals were capped with trioctylphosphine oxide/trioctylphosphine/pyridine (TOPO/TOP). There appear four sharp absorption peaks within the region of 315 to 355 nm for the dispersion solution containing the capped nanocrystals. The multiple peaks are proposed to be originating from the energy level splitting of 1S electronic state into four discrete sub-levels, where electrons were excited into the conduction band and thus four exciton absorption peaks were produced. [Figure not available: see fulltext.

  16. Chemical and orbital fluctuations in Ba3CuSb2O9

    NASA Astrophysics Data System (ADS)

    Wakabayashi, Yusuke; Nakajima, Daisuke; Ishiguro, Yuki; Kimura, Kenta; Kimura, Tsuyoshi; Tsutsui, Satoshi; Baron, Alfred Q. R.; Hayashi, Kouichi; Happo, Naohisa; Hosokawa, Shinya; Ohwada, Kenji; Nakatsuji, Satoru

    2016-06-01

    Structural fluctuation in Ba3CuSb2O9 , which is proposed to exhibit a spin-orbital entangled state, has been studied by diffuse x-ray scattering, x-ray fluorescence holography, and inelastic x-ray scattering. Two kinds of spatial fluctuations are observed: temperature-independent and temperature-dependent ones. The former is related to Cu/Sb arrangement. The short-range chemical correlation in Ba3CuSb2O9 is honeycomblike, whereas the correlation length is as short as the diameter of the honeycomb unit. The temperature variation of ferro- and antiferro-orbital correlations is extracted from Huang scattering intensity distributions. Both of these correlations increase with decreasing temperature down to 60 K, which corresponds to the energy of magnetic interaction of Ba3CuSb2O9 . A wide distribution of the characteristic time scale of the orbital motion is proposed from the spatial fluctuation of the ionic arrangement in Ba3CuSb2O9 .

  17. Temperature-dependent thermal expansion of cast and hot-pressed LAST (Pb-Sb-Ag-Te) thermoelectric materials

    SciTech Connect

    Ren, Fei; Hall, Bradley D.; Case, Eldon D; Timm, Edward J; Trejo, Rosa M; Meisner, Roberta Ann; Lara-Curzio, Edgar

    2009-01-01

    The thermal expansion for two compositions of cast and hot-pressed LAST (Pb Sb Ag Te) n-type thermoelectric materials has been measured between room temperature and 673K via thermomechanical analysis (TMA). In addition, using high-temperature X-ray diffraction (HT-XRD), the thermal expansion for both cast and hot-pressed LAST materials was determined from the temperature-dependent lattice parameters measured between room temperature and 623 K. The TMA and HT-XRD determined values of the coefficient of thermal expansion (CTE) for the LAST compositions ranged between 20106K1 and 24106K1, which is comparable to the CTE values for other thermoelectric materials including PbTe and Bi2Te3. The CTE of the LAST specimens with a higher Ag content (Ag0.86Pb19Sb1.0Te20) exhibited a higher CTE value than that of the LAST material with a lower Ag content (Ag0.43Pb18Sb1.2Te20). In addition, a peak in the temperature-dependent CTE was observed between room temperature and approximately 450K for both the cast and hot-pressed LAST with the Ag0.86Pb19Sb1.0Te20 composition, whereas the CTE of the Ag0.43Pb18Sb1.2Te20 specimen increased monotonically with temperature.

  18. On squaring triangles - Structural motifs in Cu-In-Sb compounds

    NASA Astrophysics Data System (ADS)

    Müller, C. J.; Lidin, S.

    2015-11-01

    Two new ternary Cu-In-Sb compounds Cu7In2.5Sb0.5 and Cu2In0.75Sb0.25 are presented. Both compounds are Ni2In type superstructures with vacancies in the pseudohexagonal network. Additionally, the pseudocubic nature of the compounds and Ni2In type (super)structures, in general, is discussed. Remarkably, a large number of pseudo-five-fold and pseudo-three-fold axes contribute to generate a pseudocubic symmetry in the crystal structure that is reflected in pseudocubic axial ratios in Ni2In type superstructures. We find that they belong to the family of tetrahedrally close packed structures which implies that pseudocubic axial relationships simply are to be expected.

  19. Direct electrodeposition of Cu2Sb for lithium-ion battery anodes.

    PubMed

    Mosby, James M; Prieto, Amy L

    2008-08-13

    We describe the direct single potential electrodeposition of crystalline Cu2Sb, a promising anode material for lithium-ion batteries, from aqueous solutions at room temperature. The use of citric acid as a complexing agent increases the solubility of antimony salts and shifts the reduction potentials of copper and antimony toward each other, enabling the direct deposition of the intermetallic compound at pH 6. Electrodeposition of Cu2Sb directly onto conducting substrates represents a facile synthetic method for the synthesis of high quality samples with excellent electrical contact to a substrate, which is critical for further battery testing. PMID:18627144

  20. Pb-free Sn-Ag-Cu ternary eutectic solder

    DOEpatents

    Anderson, I.E.; Yost, F.G.; Smith, J.F.; Miller, C.M.; Terpstra, R.L.

    1996-06-18

    A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6 weight % Sn-about 4.7 weight % Ag-about 1.7 weight % Cu having a eutectic melting temperature of about 217 C and variants of the ternary composition wherein the relative concentrations of Sn, Ag, and Cu deviate from the ternary eutectic composition to provide a controlled melting temperature range (liquid-solid ``mushy`` zone) relative to the eutectic melting temperature (e.g. up to 15 C above the eutectic melting temperature). 5 figs.

  1. Pb-free Sn-Ag-Cu ternary eutectic solder

    DOEpatents

    Anderson, Iver E.; Yost, Frederick G.; Smith, John F.; Miller, Chad M.; Terpstra, Robert L.

    1996-06-18

    A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6 weight % Sn-about 4.7 weight % Ag-about 1.7 weight % Cu having a eutectic melting temperature of about 217.degree. C. and variants of the ternary composition wherein the relative concentrations of Sn, Ag, and Cu deviate from the ternary eutectic composition to provide a controlled melting temperature range (liquid-solid "mushy" zone) relative to the eutectic melting temperature (e.g. up to 15.degree. C. above the eutectic melting temperature).

  2. Solid Liquid Interdiffusion Bonding of Zn4Sb3 Thermoelectric Material with Cu Electrode

    NASA Astrophysics Data System (ADS)

    Lin, Y. C.; Lee, K. T.; Hwang, J. D.; Chu, H. S.; Hsu, C. C.; Chen, S. C.; Chuang, T. H.

    2016-06-01

    The ZnSb intermetallic compound may have thermoelectric applications because it is low in cost and environmentally friendly. In this study, a Zn4Sb3 thermoelectric element coated with a Ni barrier layer and a Ag reaction layer was bonded with a Ag-coated Cu electrode using a Ag/Sn/Ag solid-liquid interdiffusion bonding process. The results indicated that a Ni5Zn21 intermetallic phase formed easily at the Zn4Sb3/Ni interface, leading to sound adhesion. In addition, Sn film was found to react completely with the Ag layer to form a Ag3Sn intermetallic layer having a melting point of 480°C. The resulting Zn4Sb3 thermoelectric module can be applied at the optimized operation temperature (400°C) of Zn4Sb3 material as a thermoelectric element. The bonding strengths ranged from 14.9 MPa to 25.0 MPa, and shear tests revealed that the Zn4Sb3/Cu-joints fractured through the interior of the thermoelectric elements.

  3. Removal of Cd, Cu, Pb, and Zn from aqueous solutions by biochars.

    PubMed

    Doumer, M E; Rigol, A; Vidal, M; Mangrich, A S

    2016-02-01

    Sorption and desorption of heavy metals (Cd, Cu, Pb, and Zn) was evaluated in biochars derived from sugarcane bagasse (SB), eucalyptus forest residues (CE), castor meal (CM), green coconut pericarp (PC), and water hyacinth (WH) as candidate materials for the treatment of contaminated waters and soils. Solid-liquid distribution coefficients depended strongly on the initial metal concentration, with K d,max values mostly within the range 10(3)-10(4) L kg(-1). For all biochars, up to 95 % removal of all the target metals from water was achieved. The WH biochar showed the highest K d,max values for all the metals, especially Cd and Zn, followed by CE (for Cd and Pb) and PC (for Cd, Pb, and Zn). Sorption data were fitted satisfactorily with Freundlich and linear models (in the latter case, for the low concentration range). The sorption appeared to be controlled by cationic exchange, together with specific surface complexation at low metal concentrations. The low desorption yields, generally less than 5 %, confirmed that the sorption process was largely irreversible and that the biochars could potentially be used in decontamination applications. PMID:26438367

  4. CuSb(S,Se)2 thin film heterojunction photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Welch, Adam W.

    Thin film heterojunction solar cells based on CuSb(S,Se)2 absorbers are investigated for two primary reasons. First, antimony is more abundant and less expensive than elements used in current thin film photovoltaics, In, Ga, and Te, and so, successful integration of Sb based materials offers greater diversification and scalability of solar energy. Second, the CuSb(S,Se) 2 ternary is chemically, electronically, and optically similar to the well-known, high efficiency, CuIn(S,Se)2 based materials. It is therefore postulated that the copper antimony ternaries will have similar defect tolerant electronic transport that may allow for similar highly efficient photoconversion. However, CuSb(S,Se)2 forms a layered crystal structure, different from the tetrahedral coordination found in conventional solar absorbers, due to the non-bonding lone pair of electrons on the antimony site. Thus examination of 2D antimony ternaries will lend insight into the role of structure in photoconversion processes. To address these questions, the semiconductors of interest (CuSbS 2 & CuSbSe2) were first synthesized on glass by combinatorial methods, to more quickly optimize process condi- tions. Radio-frequency (RF) magnetron co-sputtering from Sb2(S,Se)3 and Cu 2(S,Se) targets were used, without rotation, to produce chemical and flux graded libraries which were then subjected to high throughput characterization of structure (XRD), composition (XRF), conductivity (4pp), and optical absorption (UV/Vis/NIR). This approach rapidly identified processes that generated phase pure material with tunable carrier concentration by applying excess Sb 2(S,Se)3 within a temperature window bound by the volatility of Sb2(S,Se)3 and stability of the ternary phase. The resulting phase pure thin films were then incor- porated into the traditional CuInGaSe2 (CIGS) substrate photovoltaic (PV) architecture, and the resulting device performance was correlated to gradients in composition, sputter flux, absorber

  5. Structural phase transition and phonon instabilities in Cu12Sb4S13

    DOE PAGESBeta

    May, Andrew F.; Delaire, Olivier A.; Niedziela, Jennifer L.; Lara-Curzio, Edgar; Susner, Michael A.; Abernathy, Douglas L.; Kirkham, Melanie J.; McGuire, Michael A.

    2016-02-08

    In this study, a structural phase transition has been discovered in the synthetic tetrahedrite Cu12Sb4S13 at approximately 88 K. Upon cooling, the material transforms from its known cubic symmetry to a tetragonal unit cell that is characterized by an in-plane ordering that leads to a doubling of the unit cell volume. Specific heat capacity measurements demonstrate a hysteresis of more than two degrees in the associated anomaly. A similar hysteresis was observed in powder x-ray diffraction measurements, which also indicate a coexistence of the two phases, and together these results suggest a first-order transition. This structural transition coincides with amore » recently-reported metal-insulator transition, and the structural instability is related to the very low thermal conductivity κ in these materials. Inelastic neutron scattering was used to measure the phonon density of states in Cu12Sb4S13 and Cu10Zn2Sb4S13, both of which possess a localized, low-energy phonon mode associated with strongly anharmonic copper displacements that suppress κ. In Cu12Sb4S13, signatures of the phase transition are observed in the temperature dependence of the localized mode, which disappears at the structural transition. In contrast, in the cubic Zn-doped material, the mode is at slightly higher-energy but observable for all temperatures, though it softens upon cooling.« less

  6. {[CuSn5 Sb3 ](2-) }2 : A Dimer of Inhomogeneous Superatoms.

    PubMed

    Wilson, Robert J; Broeckaert, Lies; Spitzer, Fabian; Weigend, Florian; Dehnen, Stefanie

    2016-09-19

    Reaction of the binary Zintl anion (Sn2 Sb2 )(2-) with the β-diketiminato complex [LCu(NCMe)] (L=nacnac=[(N(C6 H3 (i) Pr2 -2,6)C(Me))2 CH](-) ) in ethylenediamine or DMF affords the ternary cluster dimer {[CuSn5 Sb3 ](2-) }2 (1) as its [K(crypt-222)](+) salt. The chemical formulation of 1 is supported by energy-dispersive X-ray spectroscopy (EDX) and quantum chemical calculations. Each monomeric part of the dimer represents a trimetallic "[CuSn5 Sb3 ](2-) " cluster, with an architecture in between a tricapped trigonal prism and a capped square antiprism. As shown by quantum chemical investigations, the presence of Sb atoms and, in particular, of Cu atoms in the cluster skeleton makes the monomeric unit behave like an inhomogeneous superatom, which clearly prefers to dimerize, thereby producing a relatively short, yet virtually non-bonding Cu⋅⋅⋅Cu distance. PMID:27558912

  7. Structural phase transition and phonon instability in Cu12Sb4S13

    DOE PAGESBeta

    May, Andrew F.; Delaire, Olivier A.; Niedziela, Jennifer L.; Lara-Curzio, Edgar; Susner, Michael A.; Abernathy, Douglas L.; Kirkham, Melanie J.; McGuire, Michael A.

    2016-02-08

    In this study, a structural phase transition has been discovered in the synthetic tetrahedrite Cu12Sb4S13 at approximately 88 K. Upon cooling, the material transforms from its known cubic symmetry to a tetragonal unit cell that is characterized by an in-plane ordering that leads to a doubling of the unit cell volume. Specific heat capacity measurements demonstrate a hysteresis of more than two degrees in the associated anomaly. A similar hysteresis was observed in powder x-ray diffraction measurements, which also indicate a coexistence of the two phases, and together these results suggest a first-order transition. This structural transition coincides with amore » recently-reported metal-insulator transition, and the structural instability is related to the very low thermal conductivity κ in these materials. Inelastic neutron scattering was used to measure the phonon density of states in Cu12Sb4S13 and Cu10Zn2Sb4S13, both of which possess a localized, low-energy phonon mode associated with strongly anharmonic copper displacements that suppress κ. In Cu12Sb4S13, signatures of the phase transition are observed in the temperature dependence of the localized mode, which disappears at the structural transition. In contrast, in the cubic Zn-doped material, the mode is at slightly higher-energy but observable for all temperatures, though it softens upon cooling.« less

  8. Study of Cu and Pb partitioning in mine tailings using the Tessier sequential extraction scheme

    NASA Astrophysics Data System (ADS)

    Andrei, Mariana Lucia; Senila, Marin; Hoaghia, Maria Alexandra; Borodi, Gheorghe; Levei, Erika-Andrea

    2015-12-01

    The Cu and Pb partitioning in nonferrous mine tailings was investigated using the Tessier sequential extraction scheme. The contents of Cu and Pb found in the five operationally defined fractions were determined by inductively coupled plasma optical emission spectrometry. The results showed different partitioning patterns for Cu and Pb in the studied tailings. The total Cu and Pb contents were higher in tailings from Brazesti than in those from Saliste, while the Cu contents in the first two fractions considered as mobile were comparable and the content of mobile Pb was the highest in Brazesti tailings. In the tailings from Saliste about 30% of Cu and 3% of Pb were found in exchangeable fraction, while in those from Brazesti no metals were found in the exchangeable fraction, but the percent of Cu and Pb found in the bound to carbonate fraction were high (20% and 26%, respectively). The highest Pb content was found in the residual fraction in Saliste tailings and in bound to Fe and Mn oxides fraction in Brazesti tailings, while the highest Cu content was found in the fraction bound to organic matter in Saliste tailings and in the residual fraction in Brazesti tailings. In case of tailings of Brazesti medium environmental risk was found both for Pb and Cu, while in case of Saliste tailings low risk for Pb and high risk for Cu were found.

  9. Study of Cu and Pb partitioning in mine tailings using the Tessier sequential extraction scheme

    SciTech Connect

    Andrei, Mariana Lucia; Senila, Marin; Hoaghia, Maria Alexandra; Levei, Erika-Andrea; Borodi, Gheorghe

    2015-12-23

    The Cu and Pb partitioning in nonferrous mine tailings was investigated using the Tessier sequential extraction scheme. The contents of Cu and Pb found in the five operationally defined fractions were determined by inductively coupled plasma optical emission spectrometry. The results showed different partitioning patterns for Cu and Pb in the studied tailings. The total Cu and Pb contents were higher in tailings from Brazesti than in those from Saliste, while the Cu contents in the first two fractions considered as mobile were comparable and the content of mobile Pb was the highest in Brazesti tailings. In the tailings from Saliste about 30% of Cu and 3% of Pb were found in exchangeable fraction, while in those from Brazesti no metals were found in the exchangeable fraction, but the percent of Cu and Pb found in the bound to carbonate fraction were high (20% and 26%, respectively). The highest Pb content was found in the residual fraction in Saliste tailings and in bound to Fe and Mn oxides fraction in Brazesti tailings, while the highest Cu content was found in the fraction bound to organic matter in Saliste tailings and in the residual fraction in Brazesti tailings. In case of tailings of Brazesti medium environmental risk was found both for Pb and Cu, while in case of Saliste tailings low risk for Pb and high risk for Cu were found.

  10. Thermoelectric properties of chalcopyrite type CuGaTe2 and chalcostibite CuSbS2

    NASA Astrophysics Data System (ADS)

    Kumar Gudelli, Vijay; Kanchana, V.; Vaitheeswaran, G.; Svane, A.; Christensen, N. E.

    2013-12-01

    Electronic and transport properties of CuGaTe2, a hole-doped ternary copper based chalcopyrite type semiconductor, are studied using calculations within the Density Functional Theory and solving the Boltzmann transport equation within the constant relaxation time approximation. The electronic band structures are calculated by means of the full-potential linear augmented plane wave method, using the Tran-Blaha modified Becke-Johnson potential. The calculated band gap of 1.23 eV is in agreement with the experimental value of 1.2 eV. The carrier concentration- and temperature dependent thermoelectric properties of CuGaTe2 are derived, and a figure of merit of zT = 1.69 is obtained at 950 K for a hole concentration of 3.7.1019 cm-3, in agreement with a recent experimental finding of zT = 1.4, confirming that CuGaTe2 is a promising material for high temperature thermoelectric applications. The good thermoelectric performance of p-type CuGaTe2 is associated with anisotropic transport from a combination of heavy and light bands. Also for CuSbS2 (chalcostibite), a better performance is obtained for p-type than for n-type doping. The variation of the thermopower as a function of temperature and concentration suggests that CuSbS2 will be a good thermoelectric material at low temperatures, similarly to the isostructural CuBiS2 compound.

  11. Direct spectroscopic evidence for completely filled Cu 3 d shell in BaCu2As2 and α -BaCu2Sb2

    NASA Astrophysics Data System (ADS)

    Wu, S. F.; Richard, P.; van Roekeghem, A.; Nie, S. M.; Miao, H.; Xu, N.; Qian, T.; Saparov, B.; Fang, Z.; Biermann, S.; Sefat, Athena S.; Ding, H.

    2015-06-01

    We use angle-resolved photoemission spectroscopy to extract the band dispersion and the Fermi surface of BaCu2As2 and α -BaCu2Sb2 . While the Cu 3 d bands in both materials are located around 3.5 eV below the Fermi level, the low-energy photoemission intensity mainly comes from As 4 p states, suggesting a completely filled Cu 3 d shell. The splitting of the As 3 d core levels and the lack of pronounced three-dimensionality in the measured band structure of BaCu2As2 indicate a surface state likely induced by the cleavage of this material in the collapsed tetragonal phase, which is consistent with our observation of a Cu+1 oxidation state. However, the observation of Cu states at similar energy in α -BaCu2Sb2 without the pnictide-pnictide interlayer bonding characteristic of the collapsed tetragonal phase suggests that the short interlayer distance in BaCu2As2 follows from the stability of the Cu+1 rather than the other way around. Our results confirm the prediction that BaCu2As2 is an s p metal with weak electronic correlations.

  12. Nanoscale Stabilization of New Phases in the PbTe-Sb2Te3 System: PbmSb2nTem+3n Nanocrystals

    SciTech Connect

    Soriano, Ronald B; Arachchige, Indika U; Malliakas, Christos D; Wu, Jinsong; Kanatzidis, Mercouri G

    2012-12-28

    A series of novel rock-salt-type PbmSb2nTem+3n nanocrystals (m = 2, 3, 4, 6, 8, and 10; n = 1 and 2) were successfully prepared using a colloidal synthesis route. These materials are stable only on the nanoscale and have no bulk analogues. Elemental compositions were determined using scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy (STEM/EDS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The nanocrystals exhibit well-defined band energies in the mid-IR region that are nearly independent of their atomic compositions. PbmSb2nTem+3n nanocrystals behave as metastable homogeneous solid solutions at room temperature and tend to phase separate into the respective binary PbTe + Sb2Te3 at 300 °C. Furthermore, pair distribution function (PDF) analysis suggests that the local structure of these PbmSb2nTem+3n nanocrystals is distorted with respect to the rock-salt structure.

  13. Synthesis, characterization and thermochemistry of synthetic Pb-As, Pb-Cu and Pb-Zn jarosites

    NASA Astrophysics Data System (ADS)

    Forray, Ferenc Lázár; Smith, A. M. L.; Navrotsky, A.; Wright, K.; Hudson-Edwards, K. A.; Dubbin, W. E.

    2014-02-01

    The enthalpy of formation from the elements of well characterized Pb-As, Pb-Cu, and Pb-Zn synthetic jarosites, corresponding to chemical formulas (H3O)0.68±0.03Pb0.32±0.002Fe2.86±0.14(SO4)1.69±0.08(AsO4)0.31±0.02(OH)5.59±0.28(H2O)0.41±0.02, (H3O)0.67±0.03Pb0.33±0.02Fe2.71±0.14Cu0.25±0.01(SO4)2±0.00(OH)5.96±0.30(H2O)0.04±0.002 and (H3O)0.57±0.03Pb0.43±0.02Fe2.70±0.14Zn0.21±0.01(SO4)2±0.00(OH)5.95±0.30(H2O)0.05±0.002, was measured by high temperature oxide melt solution calorimetry and gave ΔH°f = -3691.2 ± 8.6 kJ/mol, ΔH°f = -3653.6 ± 8.2 kJ/mol, and ΔH°f = -3669.4 ± 8.4 kJ/mol, respectively. Using estimated entropies, the standard Gibbs free energy of formation from elements at 298 K ΔG°f of the three compounds were calculated to be -3164.8 ± 9.1, -3131.4 ± 8.7, and -3153.6 ± 8.9 kJ/mol, respectively. Based on these free energies, their log Ksp values are -13.94 ± 1.89, -4.38 ± 1.81 and -3.75 ± 1.80, respectively. For this compounds, a log10{Pb2+}-pH diagram is presented. The diagram shows that the formation of Pb-As jarosite may decrease aqueous arsenic and lead concentrations to meet drinking water standards. The new thermodynamic data confirm that transformation of Pb-As jarosite to plumbojarosite is thermodynamically possible.

  14. Synthesis of BiPbSrCaCuO superconductor

    DOEpatents

    Hults, William L.; Kubat-Martin, Kimberly A.; Salazar, Kenneth V.; Phillips, David S.; Peterson, Dean E.

    1994-01-01

    A process and a precursor composition for preparing a lead-doped bismuth-strontium-calcium-copper oxide superconductor of the formula Bi.sub.a Pb.sub.b Sr.sub.c Ca.sub.d Cu.sub.e O.sub.f wherein a is from about 1.7 to about 1.9, b is from about 0.3 to about 0.45, c is from about 1.6 to about 2.2, d is from about 1.6 to about 2.2, e is from about 2.97 to about 3.2 and f is 10.+-.z by reacting a mixture of Bi.sub.4 Sr.sub.3 Ca.sub.3 Cu.sub.4 O.sub.16.+-.z, an alkaline earth metal cuprate, e.g., Sr.sub.9 Ca.sub.5 Cu.sub.24 O.sub.41, and an alkaline earth metal plumbate, e.g., Ca.sub.2-x Sr.sub.x PbO.sub.4 wherein x is about 0.5, is disclosed.

  15. Synthesis of BiPbSrCaCuO superconductor

    DOEpatents

    Hults, W.L.; Kubat-Martin, K.A.; Salazar, K.V.; Phillips, D.S.; Peterson, D.E.

    1994-04-05

    A process and a precursor composition for preparing a lead-doped bismuth-strontium-calcium-copper oxide superconductor of the formula Bi[sub a]Pb[sub b]Sr[sub c]Ca[sub d]Cu[sub e]O[sub f] wherein a is from about 1.7 to about 1.9, b is from about 0.3 to about 0.45, c is from about 1.6 to about 2.2, d is from about 1.6 to about 2.2, e is from about 2.97 to about 3.2 and f is 10[+-]z by reacting a mixture of Bi[sub 4]Sr[sub 3]Ca[sub 3]Cu[sub 4]O[sub 16[+-]z], an alkaline earth metal cuprate, e.g., Sr[sub 9]Ca[sub 5]Cu[sub 24]O[sub 41], and an alkaline earth metal plumbate, e.g., Ca[sub 2[minus]x]Sr[sub x]PbO[sub 4] wherein x is about 0.5, is disclosed.

  16. Stripping Voltammetry of Pb and Cu using a Microcantilever Electrode

    SciTech Connect

    Bange, Adam; Brown, Gilbert M; Senesac, Larry R; Thundat, Thomas George

    2009-01-01

    Microfabricated silicon microcantilevers coated with gold on one side have been used as working electrode in a three-electrode electrochemical arrangement. In addition to electrochemical current, cantilever bending has been used as a signal for monitoring electrode reactions on the cantilever surface. The microcantilever bending was measured by an optical beam deflection method as the surface potential was scanned and electrochemical reactions occurred on the surface. The microcantilever bending due to differential surface stress was used to sense Pb and Cu using cyclic voltammetry (CV) and linear sweep stripping voltammetry (LSSV).

  17. Internally consistent database for sulfides and sulfosalts in the system Ag 2S-Cu 2S-ZnS-FeS-Sb 2S 3-As 2S 3: Update

    NASA Astrophysics Data System (ADS)

    Sack, Richard O.

    2005-03-01

    The thermodynamic database for Ag 2S-Cu 2S-ZnS-FeS-Sb 2S 3-As 2S 3 sulfides and sulfosalts applicable to temperatures above 119°C has been updated based on the results of recent petrologic, experimental, and theoretical studies. Solution and end-member properties of fahlore [˜(Ag,Cu) 10(Fe,Zn) 2(Sb,As) 4S 13] have been adjusted to allow for (1) revisions of the description of Fe-Zn partitioning with sphalerite that incorporate sphalerite activity-composition relations derived from the cluster variation method (CVM) model of a previous study, (2) the assumption that the miscibility gaps observed in high-Ag fahlores from the Husky Mine (Yukon, Canada) approximate a temperature of 170°C, and (3) an increase in the Ag-Cu partitioning between fahlore and polybasite (Ag,Cu) 16(Sb,As) 2S 11 required to reproduce compositions of fahlore in the polybasite + Sb-fahlore + ZnS sphalerite assemblage reported in previous experimental studies. The resulting minor parameter adjustments produce a database that demonstrably reproduces the composition data reported for a wide-range of sulfide ore deposits. They result in revised estimates for the Gibbs energies of formation of end-member fahlore components from the simple sulfides that, except for Cu 10Zn 2Sb 4S 13, are less temperature dependent than those previously inferred (at 200 and 400°C: -23.27 and -24.84 kJ/gfw for Ag 10Zn 2Sb 4S 13, -115.18 and -116.57 kJ/gfw for Cu 10Zn 2Sb 4S 13, -85.14 and -75.20 kJ/gfw for Cu 10Fe 2Sb 4S 13, and -3.81 and 9.10 kJ/gfw for Ag 10Fe 2Sb 4S 13). The database is extended to PbS-bearing supersystems containing the galena + fahlore + sphalerite assemblage. Predicted initial Ag-contents of galena calculated from this database agree with those inferred from petrological studies of Ag-Pb-Zn ores from the Coeur d'Alene district, Idaho, USA and Julcani, Peru.

  18. Electronic structure of InTe, SnAs and PbSb: Valence-skip compound or not?

    NASA Astrophysics Data System (ADS)

    Hase, Izumi; Yasutomi, Kouki; Yanagisawa, Takashi; Odagiri, Kousuke; Nishio, Taichiro

    2016-08-01

    InTe, SnAs and PbSb formally have unusual valence states, In2+, Sn3+ and Pb3+. All of them have B1 crystal structure at some pressure range. They are candidates of the valence-skip compound, which may have negative effective Coulomb interaction Ueff < 0. Negative-U Hubbard model is known to show charge-density wave or superconductivity in some parameter region. In fact, SnAs becomes superconducting at ambient pressure. InTe has a kind of charge-density wave at ambient pressure, and it becomes superconducting at high pressure. We investigated their electronic structures by ab-initio calculations, and calculated the number of s-electrons at the cation site. We found that InTe is favorable to emerge valence skip, while PbSb is not favorable for valence skip. SnAs is between these two. These findings well agree with the experimental results.

  19. Thermoelectric and mechanical properties of spark plasma sintered Cu{sub 3}SbSe{sub 3} and Cu{sub 3}SbSe{sub 4}: Promising thermoelectric materials

    SciTech Connect

    Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Toutam, Vijaykumar; Sharma, Sakshi; Singh, Niraj Kumar; Dhar, Ajay

    2014-12-29

    We report the synthesis of thermoelectric compounds, Cu{sub 3}SbSe{sub 3} and Cu{sub 3}SbSe{sub 4}, employing the conventional fusion method followed by spark plasma sintering. Their thermoelectric properties indicated that despite its higher thermal conductivity, Cu{sub 3}SbSe{sub 4} exhibited a much larger value of thermoelectric figure-of-merit as compared to Cu{sub 3}SbSe{sub 3}, which is primarily due to its higher electrical conductivity. The thermoelectric compatibility factor of Cu{sub 3}SbSe{sub 4} was found to be ∼1.2 as compared to 0.2 V{sup −1} for Cu{sub 3}SbSe{sub 3} at 550 K. The results of the mechanical properties of these two compounds indicated that their microhardness and fracture toughness values were far superior to the other competing state-of-the-art thermoelectric materials.

  20. Vibrational spectroscopic study of the antimonate mineral bindheimite Pb 2Sb 2O 6(O,OH)

    NASA Astrophysics Data System (ADS)

    Bahfenne, Silmarilly; Frost, Ray L.

    2009-09-01

    Raman spectroscopy complimented with infrared spectroscopy has been used to characterise the antimonate mineral bindheimite Pb 2Sb 2O 6(O,OH). The mineral is characterised by an intense Raman band at 656 cm -1 assigned to SbO stretching vibrations. Other lower intensity bands at 664, 749 and 814 cm -1 are also assigned to stretching vibrations. This observation suggests the non-equivalence of SbO units in the structure. Low intensity Raman bands at 293, 312 and 328 cm -1 are assigned to the OSbO bending vibrations. Infrared bands at 979, 1008, 1037 and 1058 cm -1 may be assigned to δOH deformation modes of SbOH units. Infrared bands at 1603 and 1640 cm -1 are assigned to water bending vibrations, suggesting that water is involved in the bindheimite structure. Broad infrared bands centred upon 3250 cm -1 supports this concept. Thus the true formula of bindheimite is questioned and probably should be written as Pb 2Sb 2O 6(O,OH,H 2O).

  1. Electrochemical degradation of nitrobenzene by anodic oxidation on the constructed TiO2-NTs/SnO2-Sb/PbO2 electrode.

    PubMed

    Chen, Yong; Li, Hongyi; Liu, Weijing; Tu, Yong; Zhang, Yaohui; Han, Weiqing; Wang, Lianjun

    2014-10-01

    The interlayer of Sb-doped SnO2 (SnO2-Sb) and TiO2 nanotubes (TiO2-NTs) on Ti has been introduced into the PbO2 electrode system with the aim to reveal the mechanism of enhanced electrochemical performance of TiO2-NTs/SnO2-Sb/PbO2 electrode. In contrast with the traditional Ti/SnO2-Sb/PbO2 electrode, the constructed PbO2 electrode has a more regular and compact morphology with better oriented crystals of lower size. The TiO2-NTs/SnO2-Sb interlayer prepared by electrodeposition process improves PbO2 coating structure effectively, and enhances the electrochemical performance of PbO2 electrode. Kinetic analyses indicated that the electrochemical oxidation of nitrobenzene on the PbO2 electrodes followed pseudo-first-order reaction, and mass transport was enhanced at the constructed electrode. The accumulation of nitrocompounds of degradation intermediates on constructed electrode was lower, and almost all of the nitro groups were eliminated from aromatic rings after 6h of electrolysis. Higher combustion efficiency was obtained on the constructed TiO2-NTs/SnO2-Sb/PbO2 electrode. The intermediates of nitrobenzene oxidation were confirmed by IC and GC/MS. PMID:25065789

  2. Thermoelectric properties of chalcopyrite type CuGaTe{sub 2} and chalcostibite CuSbS{sub 2}

    SciTech Connect

    Kumar Gudelli, Vijay; Kanchana, V.; Vaitheeswaran, G.; Svane, A.; Christensen, N. E.

    2013-12-14

    Electronic and transport properties of CuGaTe{sub 2}, a hole-doped ternary copper based chalcopyrite type semiconductor, are studied using calculations within the Density Functional Theory and solving the Boltzmann transport equation within the constant relaxation time approximation. The electronic band structures are calculated by means of the full-potential linear augmented plane wave method, using the Tran-Blaha modified Becke-Johnson potential. The calculated band gap of 1.23 eV is in agreement with the experimental value of 1.2 eV. The carrier concentration- and temperature dependent thermoelectric properties of CuGaTe{sub 2} are derived, and a figure of merit of zT = 1.69 is obtained at 950 K for a hole concentration of 3.7·10{sup 19} cm{sup −3}, in agreement with a recent experimental finding of zT = 1.4, confirming that CuGaTe{sub 2} is a promising material for high temperature thermoelectric applications. The good thermoelectric performance of p-type CuGaTe{sub 2} is associated with anisotropic transport from a combination of heavy and light bands. Also for CuSbS{sub 2} (chalcostibite), a better performance is obtained for p-type than for n-type doping. The variation of the thermopower as a function of temperature and concentration suggests that CuSbS{sub 2} will be a good thermoelectric material at low temperatures, similarly to the isostructural CuBiS{sub 2} compound.

  3. Magnetic properties of nanocrystalline FeCuNb(Sb/W)SiB alloys

    SciTech Connect

    Degro, J.; Vojtanik, P.; Konc, M.; Zentko, A.; Csach, K.; Ocelik, V.

    1994-03-01

    The magnetic relaxation {Delta}r/r, the perminvar critical field H{sub CR}, the initial susceptibility {chi}{sub 10}, the coercive field H{sub c} as a function of annealing temperature in Fe{sub 73.5}Cu{sub 1}Nb{sub 2.95}Sb{sub 0.05}Si{sub 13.5}B{sub 9} and Fe{sub 73.5}Cu{sub 1}W{sub 3}Si{sub 13.5}B{sub 9} alloys were investigated. DSC measurements and thermomagnetic analyses were also done. The results using random anisotropy model can be explained.

  4. A study of transport properties in Cu and P doped ZnSb

    SciTech Connect

    Valset, K.; Song, X.; Finstad, T. G.

    2015-01-28

    ZnSb samples have been doped with copper and phosphorus and sintered at 798 K. Electronic transport properties are interpreted as being influenced by an impurity band close to the valence band. At low Cu dopant concentrations, this impurity band degrades the thermoelectric properties as the Seebeck coefficient and effective mass are reduced. At carrier concentrations above 1 × 10{sup 19 }cm{sup −3}, the Seebeck coefficient in Cu doped samples can be described by a single parabolic band.

  5. Thermal stability of active/inactive nanocomposite anodes based on Cu2Sb in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Allcorn, Eric; Kim, Sang-Ok; Manthiram, Arumugam

    2015-12-01

    Various active/inactive nanocomposites of Cu2Sb-Al2O3@C, Cu2Sb-TiC, and Cu2Sb-TiC@C have been synthesized by high energy mechanical milling and investigated by differential scanning calorimetry (DSC) to determine the lithiated phase stability and heat generation arising from these electrodes. The milling process reduces the Li3Sb phase stability, relative to the un-milled samples, to below ∼200 °C. However, the incorporation of the reinforcing, inactive phases Al2O3, TiC, and carbon black offer a slight improvement. DSC curves also show that the low-temperature heat generation in the SEI-layer reaction range is not noticeably altered by either the milling process or the addition of the inactive phases. A strong exothermic peak is observed at ∼200 °C for the 0% state of charge electrodes of Cu2Sb-Al2O3@C and Cu2Sb-TiC@C that was caused by the incorporation of carbon black into the composite. This peak was not present in the electrodes of milled Cu2Sb or Cu2Sb-TiC, suggesting that efforts to extend the cycle life of alloy anodes should avoid carbon black due to its destabilizing effects on delithiated electrodes. Fourier Transform infrared spectroscopy analysis indicates that the reaction arising from the incorporation of carbon black is tied to a low-temperature breakdown of the lithium salt LiPF6.

  6. An embedded atom method interatomic potential for the Cu-Pb system

    NASA Astrophysics Data System (ADS)

    Hoyt, J. J.; Garvin, J. W.; Webb, E. B., III; Asta, Mark

    2003-05-01

    A simple procedure is used to formulate a Cu-Pb pair interaction function within the embedded atom (EAM) method framework. Embedding, density and pair functions for pure Cu and pure Pb are taken from previously published EAM studies. Optimization of the Cu-Pb potential was achieved by comparing with experiment the computed heats of mixing for Cu-Pb liquid alloys and the equilibrium phase diagram, the latter being determined via a thermodynamic integration technique. The topology of the temperature-composition phase diagram computed with this EAM potential is consistent with experiment and features a liquid-liquid miscibility gap, low solubility of Pb in solid Cu and a monotectic reaction at approximately 1012 K.

  7. New data on the composition of jordanite-geocronite Pb-Sb-As sulfosalts at the Berezitovoe deposit (Upper Amur Region, Russia)

    NASA Astrophysics Data System (ADS)

    Vakh, A. S.; Avchenko, O. V.; Goryachev, N. A.; Gvozdev, V. I.; Karabtsov, A. A.

    2016-04-01

    New data on the composition of jordanite-geocronite Pb-Sb-As sulfosalts in the vein-disseminated gold ore at the Berezitovoe deposit were provided. Within the studied quartz-sulfide sample, some grains of Pb-Sb-As sulfosalts, uniform in composition and azonal, are drastically different from each other in As and Sb contents forming a quasi-continuous range of solid compounds from jordanite to geocronite. Jordanite-geocronite minerals at the Berezitovoe deposit (relative to the Darasun deposit) are characterized by a higher Pb concentration with a low polymetal total. It is assumed that such typomorphic features of the composition of Pb-Sb-As sulfosalts are indicative of specific formation conditions of gold mineralization in polymetallic ores at the Berezitovoe deposit.

  8. n-type to p-type crossover in quaternary Bi{sub x}Sb{sub y}Pb{sub z}Se{sub 3} single crystals

    SciTech Connect

    Kasparova, J.; Drasar, C; Krejcova, A.; Benes, L.; Lost'ak, P.; Chen Wei; Zhou Zhenhua; Uher, C.

    2005-05-15

    We report on the preparation and some physical properties of a quaternary system based on Bi{sub 2}Se{sub 3} codoped with Sb and Pb. Single-crystal samples were prepared using the Bridgman technique and were characterized by measurements of the lattice parameters, electrical resistivity, Hall coefficient, Seebeck coefficient, and thermal conductivity. Atomic emission spectroscopy was used to find the concentration profiles of Sb and Pb along the single-crystalline ingots. Progressive codoping of the Bi{sub 2}Se{sub 3} crystal lattice with Sb and Pb leads to a crossover of the initially n-type conduction to that of the p type. It is assumed that both Sb and Pb enter the Bi sublattice. Physical properties as well as the change in the dominant carrier type are discussed.

  9. High-performance Ti/Sb-SnO(2)/Pb(3)O(4) electrodes for chlorine evolution: preparation and characteristics.

    PubMed

    Shao, Dan; Yan, Wei; Cao, Lu; Li, Xiaoliang; Xu, Hao

    2014-02-28

    Chlorine evolution via electrochemical approach has wide application prospects in drinking water disinfection and wastewater treatment fields. Dimensional stable anodes used for chlorine evolution should have high stability and adequate chlorine evolution efficiency. Thus a novel and cost-effective Ti/Sb-SnO(2)/Pb(3)O(4)electrode was developed. The physicochemical and electrochemical properties as well as the chlorine evolution performances of the electrodes were investigated. The electrocatalytic activity and deactivation course of the electrodes were also explored. Results showed that this novel electrode had strong chlorine evolution ability with high current efficiency ranging from 87.3% to 93.4% depending on the operational conditions. The accelerated service life of Ti/Sb-SnO(2)/Pb(3)O(4) electrode could reach 180 h at a current density of 10,000 A m(-2) in 0.5 molL(-1) H(2)SO(4). During the electrolysis process, it was found that the conversion of Pb(3)O(4) into β-PbO(2) happened gradually on the electrode surface, which not only inhibited the leakage of hazardous Pb(2+) ion but also increased the anti-corrosion capacity of the electrode effectively. PMID:24462893

  10. Martensitic transformation behavior in Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys

    SciTech Connect

    Jang, Jai-young; Chun, Su-jin; Kim, Nam-suk; Cho, Jeung-won; Kim, Jae-hyun; Yeom, Jong-taek; Kim, Jae-il; Nam, Tae-hyun

    2013-12-15

    Graphical abstract: - Highlights: • Ag, In and Sn were soluble in TiNi matrix, while Sb, Te, Tl, Pb and Bi were not. • The B2-R-B19′transformation occurred in Ti-Ni-(Ag, In, Sn) alloys. • Solid solution hardening was essential for inducing the B2-R transformation. - Abstract: The microstructures and transformation behaviors of Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys were investigated using electron probe micro-analysis (EPMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Micro Vickers hardness tests. All specimens consisted of Ti–Ni matrices and second phase particles. Ag, In and Sn were soluble in Ti–Ni matrices with a limited solubility (≤1.0 at%), while Sb, Te, Tl, Pb and Bi were not soluble. Two-stage B2-R-B19′ transformation occurred in Ti–48.8Ni–1.2Ag, Ti–49.0Ni–1.0In and Ti–49.0Ni–1.0Sn alloys, while one-stage B2-B19′ transformation occurred in Ti–49.0Ni–1.0Ag, Ti–49.0Ni–1.0Sb, Ti–49.0Ni–1.0Te, Ti–49.0Ni–1.0Pb and Ti–49.0Ni–1.0Bi alloys. Micro Vickers hardness of the alloys displaying the B2-R-B19′ transformation (Hv 250–368) was much larger than that (

  11. Thermoelectric Inhomogeneities in (Ag(sub 1-y)SbTe2)(sub x)(PbTe)(sub 1-x)

    NASA Technical Reports Server (NTRS)

    Snyder, G. Jeffrey; Chen, Nancy; Gascoin, Franck; Mueller, Eckhard; Karpinski, Gabriele; Stiewe, Christian

    2006-01-01

    A document presents a study of why materials of composition (Ag1 ySbTe2)0.05 (PbTe)0.95 [0< or = y < or = 1] were previously reported to have values of the thermoelectric figure of merit [ZT (where Z = alpha(sup 2)/rk, alpha is the Seebeck coefficient, r is electrical resistivity, k is thermal conductivity, and T is absolute temperature)] ranging from <1 to >2. In the study, samples of (AgSbTe2)0.05(PbTe)0.95, (Ag0.67SbTe2)0.05 (PbTe)0.95, and (Ag0.55SbTe2)0.05(PbTe)0.95 were prepared by melting followed, variously, by slow or rapid cooling. Analyses of these samples by x-ray diffraction, electron microscopy, and scanning-microprobe measurements of the Seebeck coefficient led to the conclusion that these materials have a multiphase character on a scale of the order of millimeters, even though they appear homogeneous in x-ray diffraction and electron microscopy. The Seebeck measurements showed significant variations, including both n-type and p-type behavior in the same sample. These variations were found to be consistent with observed variations of ZT. The rapidly quenched samples were found to be less inhomogeneous than were the furnace-cooled ones; hence, rapid quenching was suggested as a basis of research on synthesizing more nearly uniform high-ZT samples.

  12. Thermal Transport in CuSb2O6 single crystals

    NASA Astrophysics Data System (ADS)

    Prasai, Narayan; Cohn, Joshua L.; Smith, Michael G.; Rebello, Alwyn; Neumeier, John J.

    2012-02-01

    CuSb2O6 behaves as a uniform, one-dimensional (1D) S=1/2 Heisenberg spin chain with long-range, antiferromagnetic ordering below TN˜8.5 K.ootnotetextA. Nakua et al., J. Solid State Chem. 91, 105 (1991); B. J. Gibson et al., J. Magn. Magn. Mater. 272-276, 927 (2004). Unusual for cuprates, the Cu^2+ ions lie within quite regular CuO6 octahedra and 1D magnetism appears to arise from orbital ordering driven by correlation effects.ootnotetextDeepa Kasinathan, Klaus Koepernik, and Helge Rosner, Phys. Rev. Lett. 100, 237202 (2008). We will report the results of thermal conductivity measurements on single crystals over the temperature range 5K<=T<=330 K.

  13. Study of Pb-doped Ge2Sb2Te5 in crystalline phase using first principle calculations

    NASA Astrophysics Data System (ADS)

    Singh, Janpreet; Singh, Gurinder; Kaura, Aman; Tripathi, S. K.

    2015-08-01

    To improve the phase change characteristics of Ge2Sb2Te5 (GST), doping is used as one of the effective methods. 4.4 atomic % of Pb doped GST has been studied using first principle calculations. No effect of doping on Te-Ge and Te-Sb bond length has been observed, but the Te-Te bond gets shrink with Pb doping. Due to which the Sb2Te3 segregates as a second phase, with increased doping concentration of Pb in GST alloy. Using such type of calculation, we can calculate the desirable concentration of dopant atoms to prepare the desired material. We can control any segregation in required material with pre-theoretical calculations. The metallic nature of Pd doped GST has been discussed with band structure plots. The metallic character of alloys calculated as in this paper will be helpful to understand the tuning of conductivity of phase change materials, which helps to enhance the phase change properties.

  14. Douglas fir (pseudotsuga menziesii) plantlets responses to as, PB, and sb-contaminated soils from former mines.

    PubMed

    Bonet, Amandine; Pascaud, Grégoire; Faugeron, Céline; Soubrand, Marilyne; Joussein, Emmanuel; Gloaguen, Vincent; Saladin, Gaëlle

    2016-06-01

    Phytoremediation of metalloids by conifers is not widely studied although they may be relevant for several contaminated sites, especially those located in cold areas and sometimes under dry climates. Here, seeds of Douglas fir were sown in greenhouse on three soils collected in two French former mines: a gold mine (soils L1 and L2) and a lead and silver mine (soil P). These soils are highly contaminated by Pb, As, and Sb at different concentrations. Plants were harvested after ten weeks. Growth parameters, primary metabolite content, and shoot and root ionomes were determined. Douglas firs grown on the soils L1 and P had a lower biomass than controls and a higher oxidation status whereas those grown on the soil L2 exhibited a more developed root system and only slight modifications of carbon and nitrogen nutrition. Based on trace element (TE) concentrations in shoots and roots and their translocation factor (TF), Douglas fir could be a relevant candidate for As phytoextraction (0.8 g. kg(-1) dry weight in shoots and a TF of 1.1) and may be used to phytostabilize Pb and Sb (8.8 g and 127 mg. kg(-1) in roots for Pb and Sb, respectively, and TF lower than 0.1). PMID:26361254

  15. Stabilization of As-, Pb-, and Cu-contaminated soil using calcined oyster shells and steel slag.

    PubMed

    Moon, Deok Hyun; Wazne, Mahmoud; Cheong, Kyung Hoon; Chang, Yoon-Young; Baek, Kitae; Ok, Yong Sik; Park, Jeong-Hun

    2015-07-01

    In this study, As-, Pb-, and Cu-contaminated soil was stabilized using calcined oyster shells (COS) and steel slag (SS). The As-contaminated soil was obtained from a timber mill site where chromate copper arsenate (CCA) was used as a preservative. On the other hand, Pb- and Cu-contaminated soil was obtained from a firing range. These two soils were thoroughly mixed to represent As-, Pb-, and Cu-contaminated soil. Calcined oyster shells were obtained by treating waste oyster shells at a high temperature using the calcination process. The effectiveness of stabilization was evaluated by 1-N HCl extraction for As and 0.1-N HCl extraction for Pb and Cu. The treatment results showed that As, Pb, and Cu leachability were significantly reduced upon the combination treatment of COS and SS. The sole treatment of SS (10 wt%) did not show effective stabilization. However, the combination treatment of COS and SS showed a significant reduction in As, Pb, and Cu leachability. The best stabilization results were obtained from the combination treatment of 15 wt% COS and 10 wt% SS. The SEM-EDX results suggested that the effective stabilization of As was most probably achieved by the formation of Ca-As and Fe-As precipitates. In the case of Pb and Cu, stabilization was most probably associated with the formation of pozzolanic reaction products such as CSHs and CAHs. PMID:26013737

  16. Pb isotopic constraints on the formation of the Dikulushi Cu-Pb-Zn-Ag mineralisation, Kundelungu Plateau (Democratic Republic of Congo)

    NASA Astrophysics Data System (ADS)

    Haest, Maarten; Schneider, Jens; Cloquet, Christophe; Latruwe, Kris; Vanhaecke, Frank; Muchez, Philippe

    2010-04-01

    Base metal-Ag mineralisation at Dikulushi and in other deposits on the Kundelungu Plateau (Democratic Republic of Congo) developed during two episodes. Subeconomic Cu-Pb-Zn-Fe polysulphide ores were generated during the Lufilian Orogeny (c. 520 Ma ago) in a set of E-W- and NE-SW-oriented faults. Their lead has a relatively unradiogenic and internally inhomogeneous isotopic composition (206Pb/204Pb = 18.07-18.49), most likely generated by mixing of Pb from isotopically heterogeneous clastic sources. These sulphides were remobilised and enriched after the Lufilian Orogeny, along reactivated and newly formed NE-SW-oriented faults into a chalcocite-dominated Cu-Ag mineralisation of high economic interest. The chalcocite samples contain only trace amounts of lead and show mostly radiogenic Pb isotope signatures that fall along a linear trend in the 207Pb/204Pb vs. 206Pb/204Pb diagram (206Pb/204Pb = 18.66-23.65; 207Pb/204Pb = 15.72-16.02). These anomalous characteristics reflect a two-stage evolution involving admixture of both radiogenic lead and uranium during a young fluid event possibly c. 100 Ma ago. The Pb isotope systematics of local host rocks to mineralisation also indicate some comparable young disturbance of their U-Th-Pb systems, related to the same event. They could have provided Pb with sufficiently radiogenic compositions that was added to less radiogenic Pb remobilised from precursor Cu-Pb-Zn-Fe polysulphides, whereas the U most likely originated from external sources. Local metal sources are also suggested by the 208Pb/204Pb-206Pb/204Pb systematics of combined ore and rock lead, which indicate a pronounced and diversified lithological control of the immediate host rocks on the chalcocite-dominated Cu-Ag ores. The Pb isotope systematics of polysulphide mineralisation on the Kundelungu Plateau clearly record a diachronous evolution.

  17. Rujevac Sb-Pb-Zn-As polymetallic deposit, Boranja orefield, Western Serbia: native arsenic and arsenic mineralization

    NASA Astrophysics Data System (ADS)

    Radosavljević, Slobodan A.; Stojanović, Jovica N.; Radosavljević-Mihajlović, Ana S.; Vuković, Nikola S.

    2014-02-01

    Rujevac is a low-temperature hydrothermal polymetallic Sb-Pb-Zn-As vein-type ore deposit, hosted within a volcanogenic-sedimentary zone situated in the Rujevac-Crvene Stene-Brezovica Diabase-Chert Formation (DCF) of the Podrinje Metallogenic District (PMD), Serbia. It is located several kilometers SE from the Boranja contact aureole, which is an integral part of the PMD in Western Serbia. Genetically related to the Tertiary granodioritic magma, the mineral assemblages are characterized by specific features. The mineral association of this deposit consists of sulfides, Pb-Sb(As) sulfosalts, native metals, oxides, hydroxides and gangue minerals. Chemical composition of the ore is very complex, where contents of valuable metals range as follows: Sb (0.17-24.31 wt.%), Zn (0.21-6.29 wt.%), Pb (0.15-6.33 wt.%), As (0.06-1.28 wt.%), Cd (25-747 ppm), Ag (7-408 ppm), Hg (13-473 ppm), and Tl (<1-29 ppm). Electron Probe Microanalyses (EPMA) of native arsenic from both the Rujevac and Stragari deposits showed contents of As up to 98.8 and 97.1 wt.%, with impurity contents of Sb up to 1.3 and 6.6 wt.%, and Tl up to 2 and 1.3 wt.%, respectively. Rhombohedral unit-cell parameters for native arsenic from Rujevac and Stragari deposits amount to: a = 3.760(2), c = 10.555(3) Å, V = 129.23(7) Å3 and a = 3.763(1), c = 10.560(5) Å, V = 129.48(8) Å3, respectively. Mineral assemblages, deposition order and genesis of the Rujevac polymetallic deposit were also discussed in detail. Native arsenic mineralization here has been additionally compared with similar well-known global deposits.

  18. Rujevac Sb-Pb-Zn-As polymetallic deposit, Boranja orefield, Western Serbia: native arsenic and arsenic mineralization

    NASA Astrophysics Data System (ADS)

    Radosavljević, Slobodan A.; Stojanović, Jovica N.; Radosavljević-Mihajlović, Ana S.; Vuković, Nikola S.

    2013-05-01

    Rujevac is a low-temperature hydrothermal polymetallic Sb-Pb-Zn-As vein-type ore deposit, hosted within a volcanogenic-sedimentary zone situated in the Rujevac-Crvene Stene-Brezovica Diabase-Chert Formation (DCF) of the Podrinje Metallogenic District (PMD), Serbia. It is located several kilometers SE from the Boranja contact aureole, which is an integral part of the PMD in Western Serbia. Genetically related to the Tertiary granodioritic magma, the mineral assemblages are characterized by specific features. The mineral association of this deposit consists of sulfides, Pb-Sb(As) sulfosalts, native metals, oxides, hydroxides and gangue minerals. Chemical composition of the ore is very complex, where contents of valuable metals range as follows: Sb (0.17-24.31 wt.%), Zn (0.21-6.29 wt.%), Pb (0.15-6.33 wt.%), As (0.06-1.28 wt.%), Cd (25-747 ppm), Ag (7-408 ppm), Hg (13-473 ppm), and Tl (<1-29 ppm). Electron Probe Microanalyses (EPMA) of native arsenic from both the Rujevac and Stragari deposits showed contents of As up to 98.8 and 97.1 wt.%, with impurity contents of Sb up to 1.3 and 6.6 wt.%, and Tl up to 2 and 1.3 wt.%, respectively. Rhombohedral unit-cell parameters for native arsenic from Rujevac and Stragari deposits amount to: a = 3.760(2), c = 10.555(3) Å, V = 129.23(7) Å3 and a = 3.763(1), c = 10.560(5) Å, V = 129.48(8) Å3, respectively. Mineral assemblages, deposition order and genesis of the Rujevac polymetallic deposit were also discussed in detail. Native arsenic mineralization here has been additionally compared with similar well-known global deposits.

  19. Pb-Bi-Ag-Cu-(Hg) chemistry of galena and some associated sulfosalts. A review and some new data from Colorado California and Pennsylvania

    USGS Publications Warehouse

    Foord, Eugene E.; Shawe, Daniel R.

    1989-01-01

    Galena, associated with Pb-Bi-Ag sulfosalts and simple sulfides, contains varied amounts of Ag and Bi in the Dandy vein system, Idarado mine, Ouray, Colorado; the Jackass mine, Darwin District, California; and the Leadville district, Colorado. Silver- and bismuth-bearing galena associated with minor amounts of pyrite, chalcopyrite and sphalerite occur at the Pequea mine, Lancaster County, Pennsylvania. Ag and Bi contents in the Dandy suite of galena range from about 1.4 to 3.4 and 2.5 to 6.5 wt.% respectively, and are comparable or lower in galena from the other localities. Exsolved matildite is present in galena from the Dandy, Jackass and Leadville localities. The presence in significant amounts of both Ag and Bi in a Pb-rich sulfide system is necessary for formation of PbSss (galena solid-solution). If Ag (especially) and Bi (to a lesser extent) are absent, the galena formed will be essentially pure PbS. Some minor Sb may substitute for Bi. Compositional data for all of the galena samples are in agreement with a previously proposed linear relationship between a and Ag-Bi(Sb) content. Matildite and seven additional Pb-Bi-Ag-Cu sulfosalts have been identified from the Dandy vein system, based on electron-microprobe analyses and some X-ray powder-diffraction data.

  20. Probing the mechanism of sodium ion insertion into copper antimony Cu2Sb anodes

    SciTech Connect

    Baggetto, Loic; Carroll, Kyler J.; Hah, Hien -Yoong; Johnson, Charles E.; Mullins, David R.; Unocic, Raymond R.; Johnson, Jacqueline A.; Meng, Ying Shirley; Veith, Gabriel M.

    2014-03-25

    Cycling Cu2Sb films with fluoroethylene carbonate additive drastically improves the capacity retention of the electrode compared to cycling in pure PC with about 250 mAh g-1 retained capacity for about two hundred cycles. TEM photographs reveal that the pristine films are formed of nanoparticles of 5-20 nm diameters. XRD results highlight that during the first discharge the reaction leads to the formation of Na3Sb via an intermediate amorphous phase. During charge, Na3Sb crystallites convert into an amorphous phase, which eventually crystallizes into Cu2Sb at full charge, indicating a high degree of structural reversibility. The subsequent discharge is marked by a new plateau around 0.5 V at low Na/Sb content which does not correspond to the formation of a crystalline phase. XAS data show that the fully discharged electrode material has interatomic distances matching those expected for the coexistence of Cu and Na3Sb nanodomains. At 1 V charge, the structure somewhat differs from that of Cu2Sb whereas at 2 V charge, when all Na is removed, the structure is significantly closer to that of the starting material. 121Sb Mössbauer spectroscopy isomer shifts of Cu2Sb powder (-9.67 mm s-1) and thin films (-9.65 mm s-1) are reported for the first time, and agree with the value predicted theoretically. At full discharge, an isomer shift (-8.10 mm s-1) rather close to that of a Na3Sb reference powder (-8.00 mm s-1) is measured, in agreement with the formation of Na3Sb domains evidenced by XRD and XAS data. As a result, the isomer shift at 1 V charge (-9.29 mm s-1) is close to that of the pristine material and the higher value is in agreement with the lack of full desodiation at 1 V.

  1. Involvement of CTR1 and ATP7A in lead (Pb)-induced copper (Cu) accumulation in choroidal epithelial cells.

    PubMed

    Zheng, Gang; Zhang, Jieqiong; Xu, Yan; Shen, Xuefeng; Song, Han; Jing, Jinfei; Luo, Wenjing; Zheng, Wei; Chen, Jingyuan

    2014-02-10

    The blood-cerebrospinal fluid barrier (BCB) plays a key role in maintaining copper (Cu) homeostasis in the brain. Cumulative evidences indicate that lead (Pb) exposure alters cerebral Cu homeostasis, which may underlie the development of neurodegenerative diseases. This study investigated the roles of Cu transporter 1 (CTR1) and ATP7A, two Cu transporters, in Pb-induced Cu accumulation in the choroidal epithelial cells. Pb exposure resulted in increased intracellular (64)Cu retention, accompanying with up-regulated CTR1 level. Knockdown of CTR1 using siRNA before Pb exposure diminished the Pb-induced increase of (64)Cu uptake. The expression level of ATP7A was down-regulated following the Pb exposure. ATP7A siRNA knockdown, or PCMB treatment, inhibited the (64)Cu efflux from the cells, while the following additional incubation with Pb failed to further increase the intracellular (64)Cu retention. Cu exposure, or intracellular Cu accumulation following the tetracycline (Tet)-induced overexpression of CTR1, did not result in significant change in ATP7A expression. Taken together, these data indicate that CTR1 and ATP7A play important roles in Cu transport in choroidal epithelial cells, and the Pb-induced intracellular Cu accumulation appears to be mediated, at least in part, via the alteration of CTR1 and ATP7A expression levels following Pb exposure. PMID:24316150

  2. Divalent Cu, Cd, and Pb Biosorption in Mixed Solvents

    PubMed Central

    Al-Qunaibit, M. H.

    2009-01-01

    Dead dried Chlorella vulgaris was studied in terms of its performance in binding divalent copper, cadmium, and lead ions from their aqueous or 50% v/v methanol, ethanol, and acetone solutions. The percentage uptake of cadmium ions exhibited a general decrease with decrease in dielectric constant values, while that of copper and lead ions showed a general decrease with increase in donor numbers. Uptake percentage becomes less sensitive to solvent properties the larger the atomic radius of the biosorbed ion, and uptake of copper was the most affected. FT-IR analyses revealed stability of the biomass in mixed solvents and a shift in vibrations of amide(I) and (II), carboxylate, glucose ring, and metal oxygen upon metal binding in all media. ΔνCOO values (59–69 cm−1) confirmed bidentate metal coordination to carboxylate ligands. The value of νasCOO increased slightly upon Cu, Cd, and Pb biosorption from aqueous solutions indicating lowering of symmetry, while a general decrease was noticed in mixed solvents pointing to the opposite. M–O stretching frequencies increased unexpectedly with increase in atomic mass as a result of solvent effect on the nature of binding sites. Lowering polarity of the solvent permits variations in metal-alga bonds strengths; the smaller the metal ion, the more affected. PMID:19688108

  3. Microstructure analyses and thermoelectric properties of Ag{sub 1-x}Pb{sub 18}Sb{sub 1+y}Te{sub 20}

    SciTech Connect

    Perlt, S.; Hoeche, Th.; Dadda, J.; Mueller, E.; Bauer Pereira, P.; Hermann, R.; Sarahan, M.; Pippel, E.; Brydson, R.

    2012-09-15

    This study reports microstructural investigations of long-term annealed Ag{sub 1-x}Pb{sub m}Sb{sub 1+y}Te{sub 2+m} (m=18, x=y=0, hereinafter referred to as AgPb{sub 18}SbTe{sub 20}) (Lead-Antimony-Silver-Tellurium, LAST-18) as well as of Ag{sub 1-x}Pb{sub 18}Sb{sub 1+y}Te{sub 20}, i.e. Ag-deficient and Sb-excess LAST-18 (x{ne}0,y{ne}0), respectively. Two different length scales are explored. The micrometer scale was evaluated by SEM to analyze the volume fraction and the number of secondary phases as well as the impact of processing parameters on the homogeneity of bulk samples. For AgPb{sub 18}SbTe{sub 20}, site-specific FIB liftout of TEM lamellae from thermoelectrically characterized samples was accomplished to investigate the structure on the nanometer scale. High-resolution TEM and energy-filtered TEM were performed to reveal shape and size distribution of nanoprecipitates, respectively. A hypothesis concerning the structure-property relationship is set out within the frame of a gradient annealing experiment. This study is completed by results dealing with inhomogeneities on the micrometer scale of Ag{sub 1-x}Pb{sub 18}Sb{sub 1+y}Te{sub 20} and its electronic properties. Highlights: Black-Right-Pointing-Pointer SEM and TEM microstructure investigation of long-term annealed AgPb{sub 18}SbTe{sub 20}. Black-Right-Pointing-Pointer SEM and thermoelectric studies on Ag{sub 1-x}Pb{sub 18}Sb{sub 1+y}Te{sub 20}. Black-Right-Pointing-Pointer Discussion concerning structure-property relationship in long-term annealed AgPb{sub 18}SbTe{sub 20}. Black-Right-Pointing-Pointer Correlation between Ag{sub 1-x}Pb{sub 18}Sb{sub 1+y}Te{sub 20} microscale structure and electronic properties.

  4. Melting of Pb Nanocrystals Embedded in Al, Si, and Cu Matrices

    NASA Astrophysics Data System (ADS)

    Wang, Huan; Zhu, Hongzhi

    2015-12-01

    Dispersions of nanoscale Pb particles embedded in Si, Al, and Cu matrices have been synthesized by ion implantation and subsequent annealing. The melting transitions of the embedded Pb nanocrystals with epitaxial particle/matrix interfaces were investigated by means of in situ high-temperature X-ray diffraction. Due to different levels of lattice mismatch, the Pb nanoprecipitates experience a different elastic strain in different matrices. Further analysis on the lattice constants of the embedded Pb nanocrystals gives unambiguous evidence of the strain-related pressure effect, which is particle size and matrix dependent, on tuning of the melting behavior of the embedded Pb nanoparticles.

  5. Phase composition and structure of aluminum Al-Cu-Si-Sn-Pb alloys

    NASA Astrophysics Data System (ADS)

    Belov, N. A.; Stolyarova, O. O.; Murav'eva, T. I.; Zagorskii, D. L.

    2016-06-01

    The structure and phase composition of cast and heat treated Al-Cu-Si-Sn-Pb alloys containing 6 wt % Sn, 2 wt % Pb, 0-4 wt % Cu, 0-10 wt % Si have been studied using calculations and experimental methods. Polythermal and isothermal sections are reported, which indicate the existence of two liquid phases. It was found that the low-melting phase is inhomogeneous and consists of individual leadand tin-based particles.

  6. Genesis of the Bangbule Pb-Zn-Cu polymetallic deposit in Tibet, western China: Evidence from zircon U-Pb geochronology and S-Pb isotopes

    NASA Astrophysics Data System (ADS)

    Kan, Tian; Zheng, Youye; Gao, Shunbao

    2016-04-01

    The Banbule Pb-Zn-Cu skarn deposit is located in the Longger-Gongbujiangda volcanic magma arc in the Gangdese-Nyainqentanglha Plate. It is the only lead-zinc polymetallic deposit discovered in the westernmost Nyainqentanglha metallogenic belt. The measured and indicated resources include 0.9 Mt of Pb+Zn (4.77% Pb and 4.74% Zn, respectively), 6499 t of Cu, and 178 t of Ag (18.75g/t Ag). The orebodies mainly occur as lenses, veins and irregular shapes in the contact zone between the quartz-porphyry and limestone of the Upper Permian Xiala Formation, or in the boundaries between limestone and sandstone. Pb-Zn-Cu mineralization in the Banbule deposit is closely associated with skarns. The ore minerals are dominated by galena, sphalerite, chalcopyrite, bornite, and magnetite, with subordinate pyrite, malachite, and azurite. The gangue minerals are mainly garnet, actinolite, diopside, quartz, and calcite. The ore-related quartz-porphyry displays LA-ICP-MS zircon U-Pb age of 77.31±0.74 Ma. The δ34S values of sulfides define a narrow range of -0.8 to 4.7‰ indicating a magmatic source for the ore-forming materials. Lead isotopic systematics yield 206Pb/204Pb of 18.698 to 18.752, 207Pb/204Pb of 15.696 to 15.760, and 208Pb/204Pb of 39.097 to 39.320. The data points are constrained around the growth curves of upper crust and orogenic belt according to the tectonic discrimination diagrams. The calculated Δβ ‑ Δγ values plot within the magmatic field according to the discrimination diagram of Zhu et al. (1995). The S-Pb isotopic data suggest that Bangbule is a typical skarn deposit, and the Pb-Zn-Cu mineralization is genetically related to the quartz-porphyry in the mining district. The discovery of the Bangbule deposit indicates that there is metallogenic potential in the westernmost Nyainqentanglha belt, which is of great importance for the exploration work in this area.

  7. Synthesis of the Pb-based superconductor of the Pb3201 phase (Pb 2Cu)Sr 0.9La 1.1CuO 6+δ by the modified polymerized complex method

    NASA Astrophysics Data System (ADS)

    Kato, Masatsune; Sakuma, Atsushi; Noji, Takashi; Koike, Yoji

    1996-02-01

    We have succeeded in obtaining single-phase samples of the Pb3201 phase (Pb 2Cu)Sr 0.9La 1.1CuO 6+δ by the modified polymerized complex method. At the first step of the synthesis, a transparent gel is found to be obtained by increasing the molar ratio of citric acid to total metal ions up to 5 without controlling the pH of the solution and without ethylene glycol. Secondly, the precursor is prepared by calcining the transparent gel. Finally, highly homogeneous samples with the onset temperature of the superconducting transition, ∼ 37 K, are obtained by sintering the precursor and subsequently annealing it. Moreover, the Pb3201 phase is found to be stable only for x = 1.1 in (Pb 2Cu)Sr 2- xLa xCuO 6+δ.

  8. Crystal structure of the new compound Pb{sub 3+x}Sb{sub 3-x}S{sub 7-x}Cl{sub 1+x}(x{approx}0.45): The homologous series Pb{sub (2+2N)}(Sb,Pb){sub (2+2N)}S{sub (2+2N)}(S,Cl){sub (4+2N)}Cl{sub N} and its polychalcogenide derivatives (N=1-3)

    SciTech Connect

    Doussier, Charlotte; Moelo, Yves Meerschaut, Alain; Leone, Philippe; Guillot-Deudon, Catherine

    2008-04-15

    The new chloro-sulfosalt Pb{sub 3+x}Sb{sub 3-x}S{sub 7-x}Cl{sub 1+x} (x{approx}0.45) has been synthesized at 500 deg. C from a mixture of PbS, PbCl{sub 2} and Sb{sub 2}S{sub 3}. It crystallizes in the orthorhombic system (space group Pbam), with a=15.194(3) A, b=23.035(5) A, c=4.0591(8) A, V=1420.6 A{sup 3}, Z=4. The crystal structure has been solved by X-ray single-crystal study, with a final R=0.0497. Deviation from stoichiometric Pb{sub 3}Sb{sub 3}S{sub 7}Cl (x coefficient) follows the substitution rule Sb{sup 3+}+S{sup 2-}{yields}Pb{sup 2+}+Cl{sup -}. Sb and Pb sub-positions within mixed (Sb,Pb) sites are discussed; Pb excess precludes any superstructure along c. A unique pure Cl position is bound only to Pb atoms with a distorted square coordination. The title compound is a rod-type structure derived from the SnS archetype, homeotypic with Pb{sub 6}Sb{sub 6}S{sub 14}(S{sub 3}), where the (S{sub 3}){sup 2-} trimer is replaced by two Cl{sup -}; this substitution is quite isovolumic. Other similar structures are: three polychalcogenides Sr{sub 6}Sb{sub 6}S{sub 14}(S{sub 3}), Pb{sub 6}Sb{sub 6}Se{sub 14}(Se{sub 3}) and Eu{sub 6}Sb{sub 6}S{sub 14}(S{sub 3}); KLa{sub 1.28}Bi{sub 3.72}S{sub 8} and its Ln isotypes; dadsonite, Pb{sub 23}Sb{sub 25}S{sub 60}Cl. Pb{sub 3+x}Sb{sub 3-x}S{sub 7-x}Cl{sub 1+x} is the N=2 member of the homologous series Pb{sub (2+2N)}(Sb,Pb){sub (2+2N)}S{sub (2+2N)}(S,Cl){sub (4+2N)}Cl{sub N}; the N=1 member corresponds to the previously known {approx}Pb{sub 4.3}Sb{sub 3.7}S{sub 8.7}Cl{sub 2.3} compound. Other polychalcogenide derivatives of this homologous series are K{sub 2}Pr{sub 2-x}Sb{sub 4+x}Se{sub 8}(Se{sub 4}) and its Ln isotypes (N=1), as well as SrBiSe{sub 3} (N=3). Such a comparative modular analysis allowed to propose a structural model for the previous synthetic 'Phase Y', {approx}Pb{sub 10}Sb{sub 10}S{sub 23}Cl{sub 4}, corresponding to the combined N=(1+2) homolog. - Graphical abstract: The title compound, Pb{sub 3+x}Sb{sub 3-x

  9. Engineering of electronic and optical properties of PbS thin films via Cu doping

    NASA Astrophysics Data System (ADS)

    Touati, Baligh; Gassoumi, Abdelaziz; Dobryden, Illia; Natile, Marta Maria; Vomiero, Alberto; Turki, Najoua Kamoun

    2016-09-01

    Copper-doped PbS polycrystalline thin films were deposited by chemical bath deposition by adding small amount of Cu (ysolution = [Cu2+]/[Pb2+]) between 0.5 and 2 at%. The composition, structure, morphology, optical and electrical properties of the films were investigated by means of X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray photoemission spectroscopy (XPS), UV-visible-near infrared (UV-Vis-NIR) spectrophotometry and Hall effect measurements. The XRD studies showed that the undoped films have PbS face centered cubic structure with (111) preferential orientation, while preferential orientation changes to (200) plane with increasing Cu doping concentration. The AFM and SEM measurements indicated that the film surfaces consisted of nanosized grains with pyramidal shape. Optical band gap was blue shifted from 0.72 eV to 1.69 eV with the increase in Cu doping concentration. The film obtained with the [Cu2+]/[Pb2+] ratio equal to 1.5 at% Cu showed the minimum resistivity of 0.16 Ω cm at room temperature and optimum value of optical band gap close to 1.5 eV. 1.5 at% Cu-doped PbS thin films exhibit the best optical and electrical properties, suitable for solar cells applications.

  10. Surface characteristics of metallic glass spheres of Au(55)Pb(22.5)Sb(22.5)

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Kendall, J. M.

    1983-01-01

    It is pointed out that the production of metallic glasses of high atomic number is currently of considerable importance for inertial confinement fusion (ICF) target applications. In connection with the present investigation, spherules of the alloy Au(55)Pb(22.5)Sb(22.5) were produced. Metallic glass was formed on solidification. With the aid of X-ray diffraction studies, it was established that the spheres were completely amorphous. A near-surface phase separation on spheres of the metallic glass could be observed. Energy dispersive spectroscopy (EDS) measurements showed that the average composition of the surface differed from that of the bulk.

  11. Spheres of the metallic glass Au55 Pb22.5 Sb22.5 and their surface characteristics

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Kendall, J. M.; Johnson, W. L.

    1982-01-01

    Spheres of the metallic glass Au55 Pb22.5 Sb22.5 have been formed up to a size of approximately 1.5 mm in diameter. X-ray diffraction was used to establish the glassy nature of the samples and to provide evidence of two phase-separated glass regions. Scanning electron microscopy provided a direct visual observation of the two-phase amorphous network on the surface of the sphere. The physical dimensions of the phase-separated regions were observed to be cooling-rate sensitive. Energy dispersive spectroscopy indicated that the compositions of these two glassy phases were Au-rich and Pb-rich, respectively, confirming the results of Kim and Johnson (1981). In addition, the spheres exhibited an unusual surface smoothness of better than + or - 250 A

  12. Effects of Cu and Ag as ternary and quaternary additions on some physical properties of SnSb7 bearing alloy

    NASA Astrophysics Data System (ADS)

    El-Bediwi, A. B.

    2004-02-01

    The structure, electrical resistivity, and elastic modulus of SnSb7 and SnSb7X (X = Cu , Ag, or Cu and Ag) rapidly solidified alloys have been investigated using X-ray diffractometer, double bridge, and dynamic resonance techniques. Copper and silver additions to SnSb result in the formation of a eutectic matrix containing embedded crystals (intermetallic phases) of SnCu, SnAg, and SnSb. The hard crystals SnCu, SnAg, and SnSb increase the overall hardness and wear resistance of SnSb bearing alloys. Addition of copper and silver improves internal friction, electrical conductivity, and elastic modulus values of SnSb rapidly solidified bearing alloys. The internal friction, elastic modulus, and electrical resistivity values are relatively sensitive to the composition of the intermediate phases in the matrix. The SbSb(7)Cu(2)g(2) has better properties (lowest internal friction, cost, adequate elastic modulus, and electrical resistivity) for bearing alloys as compared to cast iron and bronzes.

  13. Electronic and Optical Properties of Ca3MN (M = Ge, Sn, Pb, P, As, Sb and Bi) Antiperovskite Compounds

    NASA Astrophysics Data System (ADS)

    Iqbal, Samad; Murtaza, G.; Khenata, R.; Mahmood, Asif; Yar, Abdullah; Muzammil, M.; Khan, Matiullah

    2016-08-01

    The electronic and optical properties of cubic antiperovskites Ca3MN (M = Ge, Sn, Pb, P, As, Sb and Bi) were investigated by applying the full potential linearized augmented plane wave plus local orbitals (FP-LAPW + lo) scheme based on density functional theory. Different exchange correlation potentials were adopted for the calculations. The results of band structure and density of states show that, by changing the central anion of Ca3MN, the nature of the materials change from metallic (Ca3GeN, Ca3SnN, Ca3PbN) to semiconducting with small band gaps (Ca3SbN and Ca3BiN) to insulating (Ca3PN and Ca3AsN). The optical properties such as dielectric function, absorption coefficient, optical conductivity, reflectivity and refractive indices have also been calculated. The results reveal that all the studied compounds are optically active in the visible and ultraviolet energy regions, and therefore can be effectively utilized for optoelectronic devices.

  14. Anomalous temperature-dependent Young's modulus of a cast LAST (Pb-Sb-Ag-Te) thermoelectric material

    SciTech Connect

    Ren, Fei; Case, Eldon D; Timm, Edward J; Lara-Curzio, Edgar; Trejo, Rosa M

    2010-01-01

    Thermomechanical characterization is important to material evaluation and device design in the development of thermoelectric technology. In this study, we utilize the resonant ultrasound spectroscopy (RUS) technique to examine the elastic behavior of a cast LAST (Pb Sb Ag Te) material with a composition of Ag0.86Pb19Sb1.0Te20 between room temperature and 823 K. The temperature-dependent Young s modulus exhibits a monotonically decreasing trend with increasing temperature. However, an abnormal slope change in the Young s modulus temperature curve around 500 K is observed. In addition, hysteresis between heating and cooling data in the temperature range of 450 550 K is observed, which appears to be dependent on the heating/cooling rate during the RUS experiments such that the hysteresis disappears when the heating/cooling rate was decreased from 5 to 2 K min 1. In this study we propose an order disorder transition model for the anomalous temperature-dependent Young s modulus behavior observed in this study.

  15. Electronic and Optical Properties of Ca3MN (M = Ge, Sn, Pb, P, As, Sb and Bi) Antiperovskite Compounds

    NASA Astrophysics Data System (ADS)

    Iqbal, Samad; Murtaza, G.; Khenata, R.; Mahmood, Asif; Yar, Abdullah; Muzammil, M.; Khan, Matiullah

    2016-05-01

    The electronic and optical properties of cubic antiperovskites Ca3MN (M = Ge, Sn, Pb, P, As, Sb and Bi) were investigated by applying the full potential linearized augmented plane wave plus local orbitals (FP-LAPW + lo) scheme based on density functional theory. Different exchange correlation potentials were adopted for the calculations. The results of band structure and density of states show that, by changing the central anion of Ca3MN, the nature of the materials change from metallic (Ca3GeN, Ca3SnN, Ca3PbN) to semiconducting with small band gaps (Ca3SbN and Ca3BiN) to insulating (Ca3PN and Ca3AsN). The optical properties such as dielectric function, absorption coefficient, optical conductivity, reflectivity and refractive indices have also been calculated. The results reveal that all the studied compounds are optically active in the visible and ultraviolet energy regions, and therefore can be effectively utilized for optoelectronic devices.

  16. Local Jahn-Teller distortions and orbital ordering in Ba3Cu1+xSb2-xO9 investigated by neutron scattering

    DOE PAGESBeta

    Li, Bing; Feygenson, Mikhail; Brown, Craig M.; Copley, John R. D.; Iida, Kazuki

    2016-01-15

    In this study, a spin-orbital quantum liquid state is theoretically proposed in the honeycomb lattice of Ba3CuSb2O9, enabled by dynamic short-range correlations between the spin and orbital degrees of freedom. Using neutron diffraction, the local atomic structure of Ba3Cu1+xSb2-xO9 at x = 0 and 0.1 is obtained via the pair density function analysis. The results indicate that both compositions exhibit local Jahn-Teller (JT) distortions with the elongated CuO3 octahedral configuration. In Ba3Cu1.1Sb1.9O9, JT ordering of the distorted CuO3 octahedra gives rise to the orthorhombic symmetry with ferro-orbital order. On the other hand, in Ba3CuSb2O9, even though the CuO3 octahedra aremore » JT distorted, there is no long-range ordering hence the symmetry is hexagonal. Furthermore, the local singlet excitation at 5.8 meV observed in Ba3CuSb2O9 below 50 K is absent in Ba3Cu1.1Sb1.9O9. Instead, an excitation at 2.5 meV is observed in the latter, which is likely associated with short-range spin order.« less

  17. Local Jahn-Teller distortions and orbital ordering in Ba3Cu1 +xSb2 -xO9 investigated by neutron scattering

    NASA Astrophysics Data System (ADS)

    Li, Bing; Louca, Despina; Feygenson, Mikhail; Brown, Craig M.; Copley, John R. D.; Iida, Kazuki

    2016-01-01

    A spin-orbital quantum liquid state is theoretically proposed in the honeycomb lattice of Ba3CuSb2O9 , enabled by dynamic short-range correlations between the spin and orbital degrees of freedom. Using neutron diffraction, the local atomic structure of Ba3Cu1 +xSb2 -xO9 at x =0 and 0.1 is obtained via the pair density function analysis. The results indicate that both compositions exhibit local Jahn-Teller (JT) distortions with the elongated CuO3 octahedral configuration. In Ba3Cu1.1Sb1.9O9 , JT ordering of the distorted CuO3 octahedra gives rise to the orthorhombic symmetry with ferro-orbital order. On the other hand, in Ba3CuSb2O9 , even though the CuO3 octahedra are JT distorted, there is no long-range ordering hence the symmetry is hexagonal. Furthermore, the local singlet excitation at 5.8 meV observed in Ba3CuSb2O9 below 50 K is absent in Ba3Cu1.1Sb1.9O9 . Instead, an excitation at 2.5 meV is observed in the latter, which is likely associated with short-range spin order.

  18. Local Jahn-Teller distortions and orbital ordering in Ba3Cu1+xSb2-xO9 investigated by neutron scattering

    SciTech Connect

    Li, Bing; Feygenson, Mikhail; Brown, Craig; Copley, John R. D.; Iida, Kazuki

    2016-01-01

    A spin-orbital quantum liquid state is theoretically proposed in the honeycomb lattice of Ba3CuSb2O9, enabled by dynamic short-range correlations between the spin and orbital degrees of freedom. Using neutron diffraction, the local atomic structure of Ba3Cu1+xSb2-xO9 at x = 0 and 0.1 is obtained via the pair density function analysis. The results indicate that both compositions exhibit local Jahn-Teller (JT) distortions with the elongated CuO3 octahedral configuration. In Ba3Cu1.1Sb1.9O9, JT ordering of the distorted CuO3 octahedra gives rise to the orthorhombic symmetry with ferro-orbital order. On the other hand, in Ba3CuSb2O9, even though the CuO3 octahedra are JT distorted, there is no long-range ordering hence the symmetry is hexagonal. Furthermore, the local singlet excitation at 5.8 meV observed in Ba3CuSb2O9 below 50 K is absent in Ba3Cu1.1Sb1.9O9. Instead, an excitation at 2.5 meV is observed in the latter, which is likely associated with short-range spin order.

  19. Ternary eutectic growth of Ag-Cu-Sb alloy within ultrasonic field

    NASA Astrophysics Data System (ADS)

    Zhai, Wei; Hong, Zhenyu; Wei, Bingbo

    2007-08-01

    The liquid to solid transformation of ternary Ag42.4Cu21.6Sb36 eutectic alloy was accomplished in an ultrasonic field with a frequency of 35 kHz, and the growth mechanism of this ternary eutectic was examined. Theoretical calculations predict that the sound intensity in the liquid phase at the solidification interface increases gradually as the interface moves up from the sample bottom to its top. The growth mode of ( ɛ + θ + Sb) ternary eutectic exhibits a transition of “divorced eutectic—mixture of anomalous and regular structures—regular eutectic” along the sample axis due to the inhomogeneity of sound field distribution. In the top zone with the highest sound intensity, the cavitation effect promotes the three eutectic phases to nucleate independently, while the acoustic streaming efficiently suppresses the coupled growth of eutectic phases. In the meantime, the ultrasonic field accelerates the solute transportation at the solid-liquid interface, which reduces the solute solubility of eutectic phases.

  20. Photoluminescence properties of ZnS nanoparticles co-doped with Pb 2+ and Cu 2+

    NASA Astrophysics Data System (ADS)

    Yang, Ping; Lü, Mengkai; Xü, Dong; Yuan, Duolong; Zhou, Guangjun

    2001-03-01

    Nanometer-scale ZnS, ZnS:Cu, ZnS:Pb, and ZnS co-doped with Cu 2+ and Pb 2+ have been synthesized using a chemical precipitation method. X-ray diffraction analysis shows that the diameter of the particles is 2-4 nm. These nanocrystals can be doped with copper and lead during the synthesis without altering the X-ray diffraction pattern. However, doping has shifted the luminescence to 530 nm (Cu 2+-doped) and 500-550 nm (co-doped with Cu 2+ and Pb 2+). In the case of ZnS:Pb nanocrystals, a relatively broad emission band (color range from blue to yellow) has been observed and its excitation wavelength shows a red shift. The photoluminescence intensity increases as the ZnS nanoparticles co-doped with Pb 2+ and Cu 2+. The results strongly suggest that doped ZnS nanocrystals, especially two kinds of metals activated ZnS nanocrystals, form a new class of luminescent materials.

  1. Metal-Semiconductor Transition Concomitant with a Structural Transformation in Tetrahedrite Cu12Sb4S13

    NASA Astrophysics Data System (ADS)

    Tanaka, Hiromi I.; Suekuni, Koichiro; Umeo, Kazunori; Nagasaki, Toshiki; Sato, Hitoshi; Kutluk, Galif; Nishibori, Eiji; Kasai, Hidetaka; Takabatake, Toshiro

    2016-01-01

    The tetrahedrite Cu12Sb4S13 undergoes a metal-semiconductor transition (MST) at TMST = 85 K, whose mechanism remains elusive. Our Cu 2p X-ray photoemission spectroscopy study revealed the monovalent state of Cu ions occupying the two sites in this compound. This fact excludes the possibilities of previously proposed antiferromagnetic order and Jahn-Teller instability inherent in a divalent Cu system. A synchrotron X-ray diffraction study has revealed that the body-centered cubic cell of Cu12Sb4S13 transforms into a body-centered 2a × 2a × 2c tetragonal supercell below TMST, where the cell volume per formula unit expands by 0.25%. We have further studied pressure effects on the MST as well as the effects of the substitution of As for Sb. The application of pressure above 1 GPa completely inhibits the MST and leads to a metallic state, suggesting that the low-temperature structure with a larger volume becomes unstable under pressure. The As substitution also reduces the volume and suppresses the MST but the full substitution induces another transition at 124 K.

  2. Development of a new Pb-free solder: Sn-Ag-Cu

    SciTech Connect

    Miller, C.M.

    1995-02-10

    With the ever increasing awareness of the toxicity of Pb, significant pressure has been put on the electronics industry to get the Pb out of solder. This work pertains to the development and characterization of an alloy which is Pb-free, yet retains the proven positive qualities of current Sn-Pb solders while enhancing the shortcomings of Sn-Pb solder. The solder studied is the Sn-4.7Ag-1.7Cu wt% alloy. By utilizing a variety of experimental techniques the alloy was characterized. The alloy has a melting temperature of 217{degrees}C and exhibits eutectic melting behavior. The solder was examined by subjecting to different annealing schedules and examining the microstructural stability. The effect of cooling rate on the microstructure of the solder was also examined. Overall, this solder alloy shows great promise as a viable alternative to Pb-bearing solders and, as such, an application for a patent has been filed.

  3. (Tl, Pb, Cu)Sr 2(Tl, Pb, Cu) 2Cu 2O 8- δ: a nonsuperconducting Tl-1222 * cuprate with both heavy atom single and oxygen depleted double layer motifs

    NASA Astrophysics Data System (ADS)

    Otto, H. H.; Ringshandl, S.; Baltrusch, R.

    1998-05-01

    An account is given of the synthesis and structural investigation of a newly discovered tetragonal (Tl, Pb, Cu)Sr 2(Tl, Pb, Cu) 2Cu 2O 8- δ compound (Tl-1222 * phase) with both (Tl, Pb, Cu)O single and oxygen depleted (Tl, Pb, Cu) 2O x double layer motifs, space group I4/mmm, lattice parameters a=3.8405(2), c=29.2536(5) Å, and Dx=7.46 g cm -3. Micaceous and highly reflecting black single crystals of 1 mm×1 mm×3-5 μm size were obtained from a Tl 2O 3- and CuO-rich partial melt. The as-grown compound is nonsuperconducting. The very thin crystals are extremely liable to bend out of shape. Deterioration could not be observed within the period of a year under ambient conditions. The complex crystal structure has been solved using single crystals. We take note of the similarity of the unit cell dimensions to superconducting (Tl, Cu) 2Ba 2(Ca, Tl)Cu 2O 8 (Tl-2212 phase) with TlO double rocksalt layers, and compare crystal-chemical details of similar compounds. Apart from the possibility of obtaining superconducting properties by suitable doping, the mechanical properties of the new material are very attractive from the point of view of its use as highly scattering composite layers of an X-ray monochromator.

  4. The crystal structure of the new ternary antimonide Dy 3Cu 20+xSb 11-x ( x≈2)

    NASA Astrophysics Data System (ADS)

    Fedyna, L. O.; Bodak, O. I.; Fedorchuk, A. O.; Tokaychuk, Ya. O.

    2005-06-01

    New ternary antimonide Dy 3Cu 20+xSb 11-x ( x≈2) was synthesized and its crystal structure was determined by direct methods from X-ray powder diffraction data (diffractometer DRON-3M, Cu Kα-radiation, R=6.99%,R=12.27%,R=11.55%). The compound crystallizes with the own cubic structure type: space group F 4¯ 3m, Pearson code cF272, a=16.6150(2) Å,Z=8. The structure of the Dy 3Cu 20Sb 11-x ( x≈2) can be obtained from the structure type BaHg 11 by doubling of the lattice parameter and subtraction of 16 atoms. The studied structure was compared with the structures of known compounds, which crystallize in the same space group with similar cell parameters.

  5. Understanding nanostructures in thermoelectric materials: an electron microscopy study of AgPb{sub 18}SbSe{sub 20} crystals.

    SciTech Connect

    Lioutas, C. B.; Frangis, N.; Todorov, I.; Chung, D. Y.; Kanatzidis, M. G.; Materials Science Division; Aristotle Univ. Thessaloniki; Northwestern Univ.

    2010-01-01

    The characterization and understanding of the presence of nanostructuring in bulk thermoelectric materials requires real space atomic level information. We report electron diffraction and high-resolution transmission electron microscopy studies of crystals of the system AgPb{sub 18}SbSe{sub 20} (=18PbSe + AgSbSe{sub 2}) which reveal that this system is nanostructured rather than a solid solution. Nanocrystals of varying sizes are found, endotaxially grown in the matrix of PbSe (phase A), and consist of two phases, a cubic one (phase B) and a tetragonal one (phase C). Well-defined coherent interfaces between the phases in the same nanocrystals are observed. On the basis of the results of combined electron crystallography techniques, we propose reasonable structural models for the phases B and C. There are significant differences in the nanostructuring chemistry between AgPb{sub 18}SbSe{sub 20} and the telluride analog AgPb{sub 18}SbTe{sub 20} (LAST-18).

  6. Magnetic properties of RE5Ir2X (RE = Y, Gd-Ho, X = Sn, Sb, Pb, Bi) and magnetocaloric characterization of Gd5Ir2X

    NASA Astrophysics Data System (ADS)

    Schäfer, Konrad; Schwickert, Christian; Niehaus, Oliver; Winter, Florian; Pöttgen, Rainer

    2014-09-01

    Systematic phase analytical studies of the systems RE-Ir-X (X = Sn, Pb, Sb, Bi) led to 15 new stannides, plumbides, antimonides and bismuthides with the composition RE5Ir2X. The compounds have been synthesized and characterized by X-ray powder diffraction. The structures of Gd5Ir2Sb and Dy5Ir2Bi have been refined from single crystal X-ray diffractometer data: Mo5SiB2 type, I4/mcm, a = 775.2(2), c = 1361.3(5) pm, wR2 = 0.0933, 404 F2 values, 16 variables for Gd5Ir2Sb and a = 767.5(1), c = 1368.9(3) pm, wR2 = 0.0694, 571 F2 values, 16 variables for Dy5Ir2Bi. Magnetic measurements of Gd5Ir2X (X = Sn, Pb, Sb, Bi), Tb5Ir2X (X = Sn, Pb, Sb, Bi), Dy5Ir2Pb, Dy5Ir2Bi and Ho5Ir2Pb indicate ferromagnetic transitions at TC = 154.3, 159.3, 124.4, 119.3, 99.2, 98.2, 65.5, 68.6, 45.1, 35.6 and 23.5 K, respectively. Gd5Ir2Bi and Gd5Ir2Sb show an additional antiferromagnetic transition at TN = 118.5 and 91.0 K. The magnetocaloric effect of Gd5Ir2X (X = Sn, Pb, Sb, Bi) in terms of the isothermal entropy change ΔSm is -7.3(3), -6.5(3), -8.7(3) and -9.0(3) J kg-1 K-1 at temperatures of 153, 157, 120 and 126 K for a 5 T field change. 119Sn Mössbauer spectra of Gd5Ir2Sn at 78 K show a huge transferred hyperfine field of 21.9(1) T and an isomer shift of 1.94(1) mm s-1, typical for stannides. 121Sb Mössbauer spectra of Gd5Ir2Sb at 78 K show a transferred hyperfine field of 14.2(3) T and an isomer shift of -7.45(8) mm s-1 reflecting the antimonide character.

  7. Synthesis and spectroscopic investigations of Cu- and Pb-doped colloidal ZnS nanocrystals.

    PubMed

    Ehlert, Oliver; Osvet, Andres; Batentschuk, Miroslaw; Winnacker, Albrecht; Nann, Thomas

    2006-11-23

    A novel organometallic synthesis method for the preparation of colloidal ZnS nanoparticles is presented. This method enables the synthesis of undoped ZnS nanocrystals as well as doping with Cu, Pb, or both. The particles can be covered with an undoped layer of ZnS, forming core/shell-type particles with the ZnS:Pb, ZnS:Cu, or ZnS:Cu,Pb cores. The particles were characterized via TEM, XRD, dynamic light scattering, and optical spectroscopy. We investigated the extrinsic surface defects and their coverage with an additional ZnS layer in detail by temperature-dependent luminescence and luminescence lifetime spectroscopy. PMID:17107162

  8. Electron density distribution in BaPb{sub 1-x}Sb{sub x}O{sub 3} superconducting oxides studied by double nuclear magnetic resonance methods

    SciTech Connect

    Piskunov, Yu. V. Ogloblichev, V. V.; Arapova, I. Yu.; Sadykov, A. V.; Gerashchenko, A. P.; Verkhovskii, S. V.

    2011-11-15

    The effect of charge disorder on the formation of an inhomogeneous state of the electron system in the conduction band in BaPb{sub 1-x}Sb{sub x}O{sub 3} superconducting oxides is investigated experimentally by NMR methods. The NMR spectra of {sup 17}O are measured systematically, and the contributions from {sup 17}O atoms with different cation nearest surroundings are identified. It is found that microscopic regions with an elevated spin density of charge carriers are formed within two coordination spheres near antimony ions. Nuclei of the superconducting phase of the oxide (regions with an elevated antimony concentration) microscopically distributed over the sample are detected in compounds with x = 0.25 and 0.33. Experiments in which a double resonance signal of the spin echo of {sup 17}O-{sup 207}Pb and {sup 17}O-{sup 121}Sb are measured in the metal phase of BaPb{sub 1-x}Sb{sub x}O{sub 3} oxides are carried out for the first time. The constants of indirect heteronuclear spin-spin {sup 17}O-{sup 207}Pb interaction are determined as functions of the local Knight shift {sub 207}Ks. The estimates of the constants of the indirect interaction between the nuclei of the nearest neighbors (O-Pb and Pb-Pb atoms) and analysis of evolution of the NMR spectra of {sup 17}O upon a change in the antimony concentration are convincing evidence in favor of the development of a microscopically inhomogeneous state of the electron system in the metal phase of BaPb{sub 1-x}Sb{sub x}O{sub 3} oxides.

  9. Electron density distribution in BaPb1 - x Sb x O3 superconducting oxides studied by double nuclear magnetic resonance methods

    NASA Astrophysics Data System (ADS)

    Piskunov, Yu. V.; Ogloblichev, V. V.; Arapova, I. Yu.; Sadykov, A. V.; Gerashchenko, A. P.; Verkhovskii, S. V.

    2011-11-01

    The effect of charge disorder on the formation of an inhomogeneous state of the electron system in the conduction band in BaPb1 - x Sb x O3 superconducting oxides is investigated experimentally by NMR methods. The NMR spectra of 17O are measured systematically, and the contributions from 17O atoms with different cation nearest surroundings are identified. It is found that microscopic regions with an elevated spin density of charge carriers are formed within two coordination spheres near antimony ions. Nuclei of the superconducting phase of the oxide (regions with an elevated antimony concentration) microscopically distributed over the sample are detected in compounds with x = 0.25 and 0.33. Experiments in which a double resonance signal of the spin echo of 17O-207Pb and 17O-121Sb are measured in the metal phase of BaPb1 - x Sb x O3 oxides are carried out for the first time. The constants of indirect heteronuclear spin-spin 17O-207Pb interaction are determined as functions of the local Knight shift 207 Ks. The estimates of the constants of the indirect interaction between the nuclei of the nearest neighbors (O-Pb and Pb-Pb atoms) and analysis of evolution of the NMR spectra of 17O upon a change in the antimony concentration are convincing evidence in favor of the development of a microscopically inhomogeneous state of the electron system in the metal phase of BaPb1 - x Sb x O3 oxides.

  10. Stress Relaxation Mechanisms of Sn and SnPb Coatings Electrodeposited on Cu: Avoidance of Whiskering

    NASA Astrophysics Data System (ADS)

    Sobiech, M.; Teufel, J.; Welzel, U.; Mittemeijer, E. J.; Hügel, W.

    2011-11-01

    The interrelations of microstructural evolution, phase formation, residual stress development, and whiskering behavior were investigated for the systems of Sn coating on Cu and SnPb coating on Cu during aging at room temperature. It was shown that the whisker-preventing effect of Pb addition to pure Sn can be attributed to a Pb-induced change of the stress relaxation mechanism in the coating: Pure Sn coatings, with a columnar grain morphology, relax mechanical stress via localized, unidirectional grain growth from the surface of the coating (i.e., whisker formation occurs), whereas SnPb coatings, with an equiaxed grain morphology, relax mechanical stress via uniform grain coarsening without whisker formation. It can thus be suggested that tuning of the Sn grain morphology (i.e., establishing an equiaxed grain morphology) is a straightforward method of microstructural control to suppress whisker formation at room temperature. Experimental results obtained in this project validate this conclusion.

  11. Chemical behavior of Cu, Zn, Cd, and Pb in a eutrophic reservoir: speciation and complexation capacity.

    PubMed

    Tonietto, Alessandra Emanuele; Lombardi, Ana Teresa; Choueri, Rodrigo Brasil; Vieira, Armando Augusto Henriques

    2015-10-01

    This research aimed at evaluating cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) speciation in water samples as well as determining water quality parameters (alkalinity, chlorophyll a, chloride, conductivity, dissolved organic carbon, dissolved oxygen, inorganic carbon, nitrate, pH, total suspended solids, and water temperature) in a eutrophic reservoir. This was performed through calculation of free metal ions using the chemical equilibrium software MINEQL+ 4.61, determination of labile, dissolved, and total metal concentrations via differential pulse anodic stripping voltammetry, and determination of complexed metal by the difference between the total concentration of dissolved and labile metal. Additionally, ligand complexation capacities (CC), such as the strength of the association of metals-ligands (logK'ML) and ligand concentrations (C L) were calculated via Ruzic's linearization method. Water samples were taken in winter and summer, and the results showed that for total and dissolved metals, Zn > Cu > Pb > Cd concentration. In general, higher concentrations of Cu and Zn remained complexed with the dissolved fraction, while Pb was mostly complexed with particulate materials. Chemical equilibrium modeling (MINEQL+) showed that Zn(2+) and Cd(2+) dominated the labile species, while Cu and Pb were complexed with carbonates. Zinc was a unique metal for which a direct relation between dissolved species with labile and complexed forms was obtained. The CC for ligands indicated a higher C L for Cu, followed by Pb, Zn, and Cd in decreasing amounts. Nevertheless, the strength of the association of all metals and their respective ligands was similar. Factor analysis with principal component analysis as the extraction procedure confirmed seasonal effects on water quality parameters and metal speciation. Total, dissolved, and complexed Cu and total, dissolved, complexed, and labile Pb species were all higher in winter, whereas in summer, Zn was mostly present in the

  12. Synthesis of highly phase pure (Bi, Pb)-Sr-Ca-Cu-O superconductor

    DOEpatents

    Dorris, Stephen E.; Poeppel, Roger B.; Prorok, Barton C.; Lanagan, Michael T.; Maroni, Victor A.

    1994-01-01

    An article and method of manufacture of (Bi,Pb)-Sr-Ca-Cu-O superconductor. The superconductor is manufactured by preparing a first powdered mixture of bismuth oxide, lead oxide, strontium carbonate, calcium carbonate and copper oxide. A second powdered mixture is then prepared of strontium carbonate, calcium carbonate and copper oxide. The mixtures are calcined separately with the two mixtures then combined. The resulting combined mixture is then subjected to a powder in tube deformation and thermal processing to produce a substantially phase pure (Bi,Pb)-Sr-Ca-Cu-O superconductor.

  13. Synthesis of highly phase pure (Bi, Pb)-Sr-Ca-Cu-O superconductor

    DOEpatents

    Dorris, S.E.; Poeppel, R.B.; Prorok, B.C.; Lanagan, M.T.; Maroni, V.A.

    1994-10-11

    An article and method of manufacture of (Bi,Pb)-Sr-Ca-Cu-O superconductor are disclosed. The superconductor is manufactured by preparing a first powdered mixture of bismuth oxide, lead oxide, strontium carbonate, calcium carbonate and copper oxide. A second powdered mixture is then prepared of strontium carbonate, calcium carbonate and copper oxide. The mixtures are calcined separately with the two mixtures then combined. The resulting combined mixture is then subjected to a powder in tube deformation and thermal processing to produce a substantially phase pure (Bi,Pb)-Sr-Ca-Cu-O superconductor. 5 figs.

  14. Accumulation and transport of Cd, Cu, and Pb in an estuarine salt marsh surface microlayer

    SciTech Connect

    Lion, L.W.; Leckie, J.O.

    1982-01-01

    Dissolved and particulate Cd, Cu, and Pb were measured in bulk solution and surface microlayer samples from an intertidal salt marsh in south San Francisco Bay. The phase distribution (dissolved vs. particulate) of metals was consistent with their calculated speciation in computer-simulated sea-salt matrices. Trace metal enrichment at the microlayer corresponded with physical events at the sample site. Advective exchange of Cd, Cu, and Pb between the estuary and marsh systems was dominated by transport of bulk suspended particulate metals, with an apparent net export from the marsh to the bay.

  15. Sources of Cu, Zn, Cd and Pb in rainwater at a subtropical islet offshore northern Taiwan

    NASA Astrophysics Data System (ADS)

    Cheng, Miao-Ching; You, Chen-Feng; Lin, Fei-Jan; Huang, Kuo-Fang; Chung, Chuan-Hsiung

    2011-02-01

    Pollutants derived from long-range transport and local emission impact significantly of heavy metal compositions in rainwater and aerosols. To identify their sources and relative contributions in rainwater, 47 monthly rainwater samples from January 1998 to December 2001, collected at Peng Chia Yu (PCY), a non-residential islet offshore Taiwan, were analyzed for heavy metals (i.e. Cu, Zn, Cd, and Pb) and Pb isotopic compositions. The dissolved metals concentrations of Al, Mn, Fe, Cu, Zn, Rb, Ba, and Pb in PCY rains are high in spring and winter, but low in summer. This can be understood in terms of pollutant source changes due to wind direction shifted seasonally. The average EF crust and EF seawater values calculated for Cu, Zn, Cd and Pb are far greater than 1500, suggesting their strong anthropogenic sources, also supported by the PCA results. The pollutants derived from long-range transport are the predominated heavy metals sources during the winter monsoon season, whereas local traffic emissions play the most important role during the summer monsoon period. Unique Pb isotopic fingerprints, similar to those of iron ore sinter dusts and oil combustion dusts from Shanghai and the traffic emissions from Taiwan were identified in PCY rainwater. A mixing model based on three typical end-member Pb isotopic compositions derived from Taiwan and China was applied to evaluate the pollutant sources variations.

  16. Subsolidus phase relations of the SrO-SbOx-CuO system at 1140 K in air

    SciTech Connect

    Grivel, J. -C.; Norby, P.; Andersen, N. H.

    2013-11-15

    The subsolidus phase relations of the SrO–SbOx–CuO system were investigated in air. The samples were equilibrated at 1140 K. Under these conditions, 7 binary oxide phases are stable: Sr2CuO3, SrCuO2, Sr14Cu24O41-δ, CuSb2O6, SrSb2O6, Sr2Sb2O7 and Sr7Sb2O12. The ternary section contains 10 three-phase regions. A new ternary oxide phase with an approximate Sr3Sb2CuO9 composition of was identified. It structure is related to that of Sr8W3CuO18. This phase is not superconducting above 2 K. Instead, the magnetic susceptibility indicates onset of weak ferro- or ferrimagnetism at T ≈ 30 K.

  17. (121,123)Sb and (75)As NMR and NQR investigation of the tetrahedrite (Cu12Sb4S13)--Tennantite (Cu12As4S13) system and other metal arsenides.

    PubMed

    Bastow, T J; Lehmann-Horn, J A; Miljak, D G

    2015-10-01

    This work is motivated by the recent developments in online minerals analysis in the mining and minerals processing industry via nuclear quadrupole resonance (NQR). Here we describe a nuclear magnetic resonance (NMR) and NQR study of the minerals tennantite (Cu12As4S13) and tetrahedrite (Cu12 Sb4S13). In the first part NQR lines associated with (75)As in tennantite and (121,123)Sb isotopes in tetrahedrite are reported. The spectroscopy has been restricted to an ambient temperature studies in accord with typical industrial conditions. The second part of this contribution reports nuclear quadrupole-perturbed NMR findings on further, only partially characterised, metal arsenides. The findings enhance the detection capabilities of NQR based analysers for online measurement applications and may aid to control arsenic and antimony concentrations in metal processing stages. PMID:26453410

  18. Spintronic properties of Li1.5Mn0.5Z (Z=As, Sb) alloys in the Cu2Sb structure

    NASA Astrophysics Data System (ADS)

    Damewood, Liam; Fong, C. Y.

    2014-03-01

    We investigated the spintronic properties of two formula-units of Li1.5Mn0.5As-type alloys, Li3MnZ2 (Z=As, Sb), in the Cu2Sb tetragonal crystal structure, using an ab-initio algorithm. By interchanging Mn with each Li located at four different positions, with respect to Li4Z2, two groups of configurations are formed for each type of alloy. While some lattice constant configurations showed half-metallic properties, there is no half metallicity at the optimized lattice constant. Half metallic Li3MnAs2 is found by increasing the transverse lattice constant a 1 . 4 % above the optimized value and increasing the unequal axis lattice constant c 4 . 5 % . The total energy difference compared to the optimized version is less than 1 % . We explain the lack of half-metallic phase in the Sb-type alloy by comparing the bonding features to Li4Z2. Both the modified Slater-Pauling-Kübler rule and the ionic model predict the magnetic moments of the half-metallic phases. Work at U.C. Davis was supported in part by the National Science Foundation Grant No. ECCS-1232275.

  19. Modeling non-isothermal intermetallic layer growth in the 63Sn-37Pb/Cu system

    SciTech Connect

    Vianco, P.T.; Hopkins, P.L.; Erickson, K.L.; Frear, D.R.; Davidson, R.

    1996-12-31

    A model describing diffusion-controlled growth of multiple intermetallic layers and the displacement of the interfaces between layers was developed and implemented in a 1-D computer code based on method-of-lines. The code was applied to analysis of intermetallic layer growth in isothermal solder aging experiments performed with 100 Sn/Cu and 63Sn-37Pb/Cu solder-substrate systems. Analyses indicated that intermetallic layer growth was consistent with a bulk diffusion mechanism involving Cu and/or Sn. In this work, nonisothermal solder-aging experiments were done with the 63Sn- 37Pb/Cu system using two temperature histories (4 cycles/day between 223-443 K, and 72 cycles/day between 223-443 K). Isothermal experiments were also done at 443 K. Thickness of Cu{sub 3}Sn and Cu{sub 6}Sn{sub 5} intermetallic layers were determined vs time for each temperature history. An updated version of the model and code were used to predict the intermetallic layer growth. Arrhenius expressions for diffusion coefficients in both Cu3Sn and Cu6Sn5 layers were determined. Agreement between prediction and experiment was generally good. In some cases, predicted layer growth was less than experiment, but within error. This paper describes the nonisothermal experiments and a comparison of predicted and observed layer growth vs time.

  20. Sorption behavior of Cd, Cu, Pb, and Zn and their interactions in phytoremediated soil.

    PubMed

    Trakal, L; Komárek, M; Száková, J; Tlustos, P; Tejnecký, V; Drábek, O

    2012-09-01

    The aim of our study was to compare the sorption properties of a contaminated soil before and after two types of phytoremediation (natural phytoextraction vs. phytostabilization with dolomite limestone (DL) application). Soil from a pot experiment in controlled greenhouse conditions performed for two vegetation periods was used for the study. Lead, as the main contaminant in the studied soil, was easily desorbed by Cu, especially due to the increased affinity of Cu for soil organic matter; hence input of Cu to the studied soil can present another environmental risk in soils contaminated with other metals (such as Pb). In addition, the sorption behavior of chosen metals from single-element solutions differed from multielement solutions. The obtained results proved the different sorption behavior of metals in the single-element solution compared to the multi-element ones. Soil sorption behavior of Cd, Cu, and Zn decreased with the presence of the competitive metals; nevertheless, Pb sorption potential was not influenced by other competitive metals. Natural phytoextraction showed no significant effect on the sorption of Cd, Cu, Pb, and Zn onto the soil On the other hand, phytostabilization associated with DL application improved the soil sorption efficiency of all chosen metals, especially of Cu. PMID:22908646

  1. Novodneprite (AuPb3), anyuiite [Au(Pb, Sb)2] and gold micro- and nano-inclusions within plastically deformed mantle-derived olivine from the Lherz peridotite (Pyrenees, France): a HRTEM-AEM-EELS study

    NASA Astrophysics Data System (ADS)

    Ferraris, Cristiano; Lorand, Jean-Pierre

    2015-02-01

    To contribute the problem of the missing ("invisible") gold fraction in mantle rocks, olivine grains separated from orogenic lherzolite of the peridotite body of Lherz (Eastern Pyrenees, France) have been investigated by transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). The results indicate the presence of micrometric inclusions of novodneprite, AuPb3, and anyuiite, Au(Pb,Sb)2, together with nanometric clusters of metallic gold. Both minerals have been recognised on TEM images as darker contrast inclusions and identified through selected area electron diffraction (SAED) and energy dispersive spectroscopy (EDS) analyses. Gold clusters have been indirectly identified in randomly distributed nano-sized rectangular areas that occur in TEM images obtained from the edges of olivine crystals. Within these volumes the EDS analyses reveal a constant presence of Au (0.1-0.2 wt %). High-resolution TEM (HRTEM) investigations evidence series of regularly alternating sigmoidal and ellipsoidal domains developed along [110]. The EELS investigations revealed that the Au signal (M-series lines) arises from the ellipsoidal domains. It is proposed that novodneprite and anyuiite are the result of subsolidus recrystallization of the Pyrenean lherzolites accompanied by a secondary olivine grains growth that trapped inter-granular components. Likely, a process of plastic deformation favoured the formation of edge dislocations within olivine grains and thus, the circulation through them of Au-enriched fluids. A mass balance calculation of the missing gold percentage within this lherzolite points to olivine as one of the potential hosts for about the 80 % of the "invisible" gold in form of nano-inclusions, whereas only 20 % of the whole-rock Au-budget, would be hosted within assemblages of Cu-Fe-Ni sulphides.

  2. Lead antimony sulfide (Pb5Sb8S17) solid-state quantum dot-sensitized solar cells with an efficiency of over 4%

    NASA Astrophysics Data System (ADS)

    Chang, Yi-Cheng; Suriyawong, Nipapon; Aragaw, Belete Asefa; Shi, Jen-Bin; Chen, Peter; Lee, Ming-Way

    2016-04-01

    Lead antimony sulfides are rare in nature and relatively unexplored ternary semiconductors. This work investigates the photovoltaic performance of Pb-Sb-S quantum dot-sensitized solar cells (QDSCs). Pb5Sb8S17 nanoparticles are grown on mesoporous TiO2 electrodes using the successive ionic layer adsorption reaction process. The synthesized Pb5Sb8S17 nanoparticles exhibit two attractive features for a good solar absorber material: a high optical absorption coefficient and a near optimal energy gap. Solid-state QDSCs are fabricated from the synthesized Pb5Sb8S17 nanoparticles using Spiro-OMeTAD as the hole-transporting material. The best cell yields a short-circuit current density Jsc of 11.92 mA cm-2, an open-circuit voltage Voc of 0.48 V, a fill factor FF of 30.7% and a power conversion efficiency (PCE) of 1.76% under 1sun. The external quantum efficiency (EQE) spectrum covers a spectral range of 350-800 nm with a maximal EQE = 65% at λ = 450 nm. At the reduced light intensity of 10% sun, the PCE increases to 4.14% with Jsc = 2.0 mA cm-2 (which could be normalized to 20 mA cm-2 under 1 sun). This PCE is 65% higher than the best previous result. The respectable PCE and Jsc indicate that Pb5Sb8S17 could be a potential candidate for a solar absorber material.

  3. An experimental and thermodynamic equilibrium investigation of the Pb, Zn, Cr, Cu, Mn and Ni partitioning during sewage sludge incineration.

    PubMed

    Liu, Jingyong; Fu, Jiewen; Ning, Xun'an; Sun, Shuiyu; Wang, Yujie; Xie, Wuming; Huang, Shaosong; Zhong, Sheng

    2015-09-01

    The effects of different chlorides and operational conditions on the distribution and speciation of six heavy metals (Pb, Zn, Cr, Cu, Mn and Ni) during sludge incineration were investigated using a simulated laboratory tubular-furnace reactor. A thermodynamic equilibrium investigation using the FactSage software was performed to compare the experimental results. The results indicate that the volatility of the target metals was enhanced as the chlorine concentration increased. Inorganic-Cl influenced the volatilization of heavy metals in the order of Pb>Zn>Cr>Cu>Mn>Ni. However, the effects of organic-Cl on the volatility of Mn, Pb and Cu were greater than the effects on Zn, Cr and Ni. With increasing combustion temperature, the presence of organic-Cl (PVC) and inorganic-Cl (NaCl) improved the transfer of Pb and Zn from bottom ash to fly ash or fuse gas. However, the presence of chloride had no obvious influence on Mn, Cu and Ni. Increased retention time could increase the volatilization rate of heavy metals; however, this effect was insignificant. During the incineration process, Pb readily formed PbSiO4 and remained in the bottom ash. Different Pb compounds, primarily the volatile PbCl2, were found in the gas phase after the addition of NaCl; the dominant Pb compounds in the gas phase after the addition of PVC were PbCl2, Pb(ClO4)2 and PbCl2O4. PMID:26354691

  4. EFFECTS OF AQUEOUS AL, CD, CU, FE(II), NI, AND ZN ON PB IMMOBILIZATION BY HYDROXYAPATITE

    EPA Science Inventory

    The effects of aqueous Al, Cd, Cu, Fe(II), Ni, or Zn on Pb immobilization by hydroxyapatite (Ca10(PO4),(OH)2) were studied. ead was removed mainly via hydroxyapatite dissolution and hydroxypyromorphite (Pb10(PO4)6(OH)2) precipitation in the presence of these metals with a Pb remo...

  5. Electrodeposition of SnSbCu Alloy on Copper from an Electrolyte with Varied Content of Antimony Chloride

    NASA Astrophysics Data System (ADS)

    Valeeva, A. Kh.; Valeev, I. Sh.

    2015-10-01

    The microstructure and chemical composition of electrodeposited alloys of the SnSbCu system with varied concentration of antimony chloride in the electrolyte have been investigated. It is shown that during electrodeposition mechanical-mixture alloys are not formed, but rather intermetallic compounds. It is found that increasing the concentration of antimony chloride in the electrolyte leads to a decrease in the tin content and cracking of the coating.

  6. Behaviors of heavy metals (Cd, Cu, Ni, Pb and Zn) in soil amended with composts.

    PubMed

    Gusiatin, Zygmunt Mariusz; Kulikowska, Dorota

    2016-09-01

    This study investigated how amendment with sewage sludge compost of different maturation times (3, 6, 12 months) affected metal (Cd, Cu, Ni, Pb, Zn) bioavailability, fractionation and redistribution in highly contaminated sandy clay soil. Metal transformations during long-term soil stabilization (35 months) were determined. In the contaminated soil, Cd, Ni and Zn were predominately in the exchangeable and reducible fractions, Pb in the reducible fraction and Cu in the reducible, exchangeable and oxidizable fractions. All composts decreased the bioavailability of Cd, Ni and Zn for up to 24 months, which indicates that cyclic amendment with compost is necessary. The bioavailability of Pb and Cu was not affected by compost amendment. Based on the reduced partition index (IR), metal stability in amended soil after 35 months of stabilization was in the following order: Cu > Ni = Pb > Zn > Cd. All composts were more effective in decreasing Cd, Ni and Zn bioavailability than in redistributing the metals, and increasing Cu redistribution more than that of Pb. Thus, sewage sludge compost of as little as 3 months maturation can be used for cyclic amendment of multi-metal-contaminated soil. PMID:26853755

  7. Study on structure and properties of CuZn40Pb alloy

    NASA Astrophysics Data System (ADS)

    Achiţei, D. C.; Minciună, M. G.; Vizureanu, P.; Sandu, A. V.; Cimpoeşu, R.; Istrate, B.

    2016-06-01

    The paper shows aspects about the behavior of Cu-Zn-Pb alloys a subjected to the temperatures variation and corrosion resistance in saline medium (sea water). The chemical composition was determined by spectral analysis on optical spectrometer, type Foundry Masters. The experiments are completed by a microstructure analysis made on scanning electronic microscope.

  8. Ages and sources of components of Zn-Pb, Cu, precious metal, and platinum group element deposits in the goodsprings district, clark county, Nevada

    USGS Publications Warehouse

    Vikre, P.; Browne, Q.J.; Fleck, R.; Hofstra, A.; Wooden, J.

    2011-01-01

    The Goodsprings district, Clark County, Nevada, includes zinc-dominant carbonate replacement deposits of probable late Paleozoic age, and lead-dominant carbonate replacement deposits, copper ?? precious metal-platinum group element (PGE) deposits, and gold ?? silver deposits that are spatially associated with Late Triassic porphyritic intrusions. The district encompasses ??500 km2 although the distribution of all deposits has been laterally condensed by late Mesozoic crustal contraction. Zinc, Pb, and Cu production from about 90 deposits was ??160,000 metric tons (t) (Zn > Pb >> Cu), 2.1 million ounces (Moz) Ag, 0.09 Moz Au, and small amounts of PGEs-Co, V, Hg, Sb, Ni, Mo, Mn, Ir, and U-were also recovered. Zinc-dominant carbonate replacement deposits (Zn > Pb; Ag ?? Cu) resemble Mississippi Valley Type (MVT) Zn-Pb deposits in that they occur in karst and fault breccias in Mississippian limestone where the southern margin of the regional late Paleozoic foreland basin adjoins Proterozoic crystalline rocks of the craton. They consist of calcite, dolomite, sphalerite, and galena with variably positive S isotope compositions (??34S values range from 2.5-13%), and highly radiogenic Pb isotope compositions (206Pb/204Pb >19), typical of MVT deposits above crystalline Precambrian basement. These deposits may have formed when southward flow of saline fluids, derived from basinal and older sedimentary rocks, encountered thinner strata and pinch-outs against the craton, forcing fluid mixing and mineral precipitation in karst and fault breccias. Lead-dominant carbonate replacement deposits (Pb > Zn, Ag ?? Cu ?? Au) occur among other deposit types, often near porphyritic intrusions. They generally contain higher concentrations of precious metals than zinc-dominant deposits and relatively abundant iron oxides after pyrite. They share characteristics with copper ?? precious metal- PGE and gold ?? silver deposits including fine-grained quartz replacement of carbonate minerals in

  9. Collective versus local Jahn-Teller distortion in Ba3CuSb2O9 : Raman scattering study

    NASA Astrophysics Data System (ADS)

    Drichko, Natalia; Broholm, Collin; Kimura, K.; Ishii, R.; Nakasutji, Satoru

    2016-05-01

    We present temperature dependent Raman spectra of single crystals of two different samples of the spin-orbital liquid candidate Ba3CuSb2O9 . The "hexagonal" sample is known to show no magnetic order down to low temperatures, while the "orthorhombic" sample undergoes a crossover into an orthorhombic crystal structure below TJT of approximately 200 K and shows spin freezing at 110 μ K . Our Raman scattering results demonstrate a strong influence of disorder in both samples. The frequencies of stretching vibrations of oxygens associated with CuSbO9 octahedra indicate a difference in the crystal structure between the hexagonal and orthorhombic samples even at room temperature. On cooling below TJT we observe new bands in the spectra of the orthorhombic sample due to a lowering of symmetry of the unit cell and a collective Jahn-Teller distortion. The spectra of the hexagonal sample show that average hexagonal symmetry is maintained at least down to 20 K. An analysis of the band shape of stretching oxygen vibrations suggests a weak disordered local Jahn-Teller distortion in the hexagonal sample of Ba3CuSb2O9 which increases slightly on cooling. This Jahn-Teller distortion is either static or dynamic with a frequency below 1.5 THz.

  10. CuSbS2: a promising semiconductor photo-absorber material for quantum dot sensitized solar cells.

    PubMed

    Liu, Zhifeng; Huang, Jiajun; Han, Jianhuan; Hong, Tiantian; Zhang, Jing; Liu, Zhihua

    2016-06-22

    A facile, low-cost, simple solution-based process for preparing novel promising chalcostibite CuSbS2 sensitized ZnO nanorod arrays, and the application of these as photoanodes of semiconductor quantum dot sensitized inorganic-organic solar cells (QDSSCs) is reported for the first time. ZnO/CuSbS2 nanofilms were designed and prepared through a simple successive ionic layer adsorption and reaction (SILAR) method and heat treatment process by employing ZnO nanorods as reactive templates. Novel efficient QDSSCs based on the ZnO/CuSbS2 nanofilms plus a solid electrolyte of poly(3-hexylthiophene) (P3HT) were formed, and a power conversion efficiency of 1.61% was achieved. The excellent photoelectric performance is attributed to the improved light absorption efficiency, widened light absorption region, ideal band gap value, and high speed electron injection and transportation. The results demonstrate that a novel ternary sensitizer (I-V-VI2) can be synthesized via a low-cost method as described here and has great promising potential as a sensitizer in solar cells. PMID:27297190

  11. Internally consistent database for sulfides and sulfosalts in the system Ag 2S-Cu 2S-ZnS-Sb 2S 3-As 2S 3

    NASA Astrophysics Data System (ADS)

    Sack, Richard O.

    2000-11-01

    An updated thermodynamic database for Ag 2S-Cu 2S-ZnS-Sb 2S 3-As 2S 3 sulfides and sulfosalts applicable to temperatures above 119°C is developed to calculate phase relations for polybasite-pearceite- and fahlore-bearing assemblages. It is based on pre-existing and new constraints on activity-composition, Ag-Cu and As-Sb partitioning, and other relations, and on experiments (200-300°C, evacuated silica tubes) conducted to define the stability of the polybasite-pearceite [(Ag 1- x,Cu x) 16(Sb 1- y,As y) 2S 11] + ZnS sphalerite assemblage with respect to assemblages containing (Ag,Cu) 2S sulfides coexisting with (Cu, Ag) 10Zn 2(Sb,As) 4S 13 fahlore sulfosalts. It was found that the thermodynamics of mixing of bcc- and hcp-(Ag,Cu) 2S solutions, which are fast-ion conductors, may be described by using site multiplicities of metals α Ag,Cu > 2 and temperature-dependent regular solution parameters. We obtained estimates for the Gibbs energies of formation for Ag 16Sb 2S 11 and Cu 16Sb 2S 11 polybasite endmembers from the simple sulfides (Ag 2S, Cu 2S, and Sb 2S 3) of -30.79 and -4.07 kJ/gfw at 200°C, and -32.04 and -0.59 kJ/gfw at 400°C, respectively, that are about one half kJ/gfw more positive and about 6 kJ/gfw more negative than those estimated by Harlov and Sack (1995b). The corresponding estimates for formation energies of Ag 10Zn 2Sb 4S 13 and Cu 10Zn 2Sb 4S 13 fahlores (-20.29 and -105.29 kJ/gfw at 200°C and -23.72 and -105.76 kJ/gfw at 400°C) are comparable to, and roughly 110 kJ/gfw more positive than, the corresponding estimates of Ebel and Sack (1994). We also determined that the Gibbs energies of the As-Sb exchange reactions: 1/4Ag 10Zn2Sb4S13+1/2Ag 16As2S11=1/2Ag 16Sb2S11+1/4Ag 10Zn2As4S13Sb-fahlorepearceitepolybasiteAs-fahlore and Ag3SbS3+1/2Ag 16As2S11=1/2Ag 16Sb2S11+Ag3AsS3pyrargyritepearceitepolybasiteproustite are, respectively, 8.75 and 0.40 kJ/gfw in the range 150-350°C, and these predictions are consistent with As-Sb partitioning relations

  12. On the role of Pb in epitaxial growth of thin Co films on Cu(111)

    NASA Astrophysics Data System (ADS)

    Mróz, S.; Otop, H.; Jankowski, Z.

    1998-05-01

    Cobalt layers were deposited at room temperature in UHV on the Cu(111) face clean and precovered with Pb. The role of Pb in the epitaxial growth of Co film was investigated with the use of combined Auger electron spectroscopy and directional elastic peak electron spectroscopy (DEPES). It has been found that the crystalline structure of Co layers is, for coverages up to 5 ML, insensitive to the precovering with lead. DEPES profiles for Co layers indicate the continuation of the stacking sequence of the fcc substrate structure. However, the presence of lead improves this structure. Namely, the contrast of particular maxima in DEPES profiles is maintained constant up to 1 ML and 2.5 ML of cobalt deposited on the Cu substrate clean and precovered with 1 ML of Pb, respectively.

  13. Bioaccessibility of Ba, Cu, Pb, and Zn in urban garden and orchard soils.

    PubMed

    Cai, Meifang; McBride, Murray B; Li, Kaiming

    2016-01-01

    Exposure of young children to toxic metals in urban environments is largely due to soil and dust ingestion. Soil particle size distribution and concentrations of toxic metals in different particle sizes are important risk factors in addition to bioaccessibility of these metals in the particles. Analysis of particle size distribution and metals concentrations for 13 soils, 12 sampled from urban gardens and 1 from orchard found that fine particles (<105 μm) comprised from 22 to 66% by weight of the tested soils, with Ba, Cu, Pb and Zn generally at higher concentrations in the finer particles. However, metal bioaccessibility was generally lower in finer particles, a trend most pronounced for Ba and Pb. Gastric was higher than gastrointestinal bioaccessibility for all metals except Cu. The lower bioaccessibility of Pb in urban garden soils compared to orchard soil is attributable to the higher organic matter content of the garden soils. PMID:26477581

  14. The magnetic structure of EuCu2Sb2

    SciTech Connect

    Ryan, D. H.; Cadogan, J. M.; Anand, V. K.; Johnston, D. C.; Flacau, R.

    2015-05-06

    Antiferromagnetic ordering of EuCu2Sb2 which forms in the tetragonal CaBe2Ge2-type structure (space group P4/nmm #129) has been studied using neutron powder diffraction and 151Eu Mössbauer spectroscopy. The room temperature 151Eu isomer shift of –12.8(1) mm/s shows the Eu to be divalent, while the 151Eu hyperfine magnetic field (Bhf) reaches 28.7(2) T at 2.1 K, indicating a full Eu2+ magnetic moment. Bhf(T) follows a smooth $S=\\frac{7}{2}$ Brillouin function and yields an ordering temperature of 5.1(1) K. Refinement of the neutron diffraction data reveals a collinear A-type antiferromagnetic arrangement with the Eu moments perpendicular to the tetragonal c-axis. As a result, the refined Eu magnetic moment at 0.4 K is 7.08(15) μB which is the full free-ion moment expected for the Eu2+ ion with $S=\\frac{7}{2}$ and a spectroscopic splitting factor of g = 2.

  15. Half-metallic antiferromagnetism in double perovskite BiPbCrCuO{sub 6}

    SciTech Connect

    Weng, Ke-Chuan; Wang, Y. K.

    2015-05-07

    The electronic structure and magnetic properties of BiPbCrCuO{sub 6} double perovskite are investigated based on first-principles density functional calculations with generalized gradient approximation (GGA) and GGA incorporated with Coulomb correlation interaction U (GGA + U). The results suggest the half-metallic (HM) and antiferromagnetic (AFM) properties of BiPbCrCuO{sub 6} double perovskite. The HM-AFM property of the double perovskite is caused by the double-exchange mechanism between neighboring Cr{sup 5+}(t{sub 2g}{sup 1}↓) and Cu{sup 2+}(t{sub 2g}{sup 3}↑t{sub 2g}{sup 3}↓e{sub g}{sup 2}↑e{sub g}↓) via the intermediate O{sup 2−}(2s{sup 2}2p{sup 6}) ion.

  16. Arsenic (As), antimony (Sb), and lead (Pb) availability from Au-mine Technosols: a case study of transfer to natural vegetation cover in temperate climates.

    PubMed

    Wanat, Nastasia; Joussein, Emmanuel; Soubrand, Marilyne; Lenain, Jean-François

    2014-08-01

    Soils from old Au-mine tailings (La Petite Faye, France) were investigated in relation to the natural vegetation cover to evaluate the risk of metals and metalloids (Pb, As, Sb) mobilizing and their potential transfer to native plants (Graminea, Betula pendula, Pteridium aquilinum, Equisetum telmateia). The soils are classified as Technosols with high contamination levels of As, Pb, and Sb. The single selective extractions tested to evaluate available fraction (CaCl2, acetic acid, A-Rhizo, and DTPA) showed low labile fractions (<5 % of bulk soil contents), but still significant levels were observed (up to 342.6 and 391.9 mg/kg for As and Pb, respectively) due to the high contamination levels of soils. Even at high soil contaminations (considered as phytotoxic levels for plants), translocation factors for native plants studied are very low resulting in low concentrations of As, Sb, and Pb in their aerial part tissues. This study demonstrates the important role of (1) native plant cover in terms of "stabilization" of these contaminants, and (2) the poor effectiveness of extraction procedures used for this type of soil assemblages, i.e., rich in specific mineral phases. PMID:24474610

  17. Accumulation of Pb, Cd, Cu and Zn in plants and hyperaccumulator choice in Lanping lead-zinc mine area, China.

    PubMed

    Yanqun, Zu; Yuan, Li; Schvartz, Christian; Langlade, Laurent; Fan, Liu

    2004-06-01

    A field survey of higher terrestrial plants growing on Lanping lead-zinc mine, China were conducted to identify species accumulating exceptionally large concentrations of Pb, Cd, Cu and Zn of 20 samples of 17 plant species. Concentrations of Pb and Zn in soil and in plant were higher than that of Cu and Cd. Significant difference was observed among the average concentrations of four heavy metals in plants (except Cd and Cu) and in soil (except Pb and Zn) (P<0.05). For the enrichment coefficient of the four heavy metals in plant, the order of average was PbCu (P<0.05). The enrichment coefficients were higher than 1 in Llex plyneura and Rhododendron annae in Paomaping for Pb, Salix cathayana, L. plyneura and R. annae in Paomaping for Cd, and R. annae in Paomaping for Zn, respectively. Concentrations and enrichment coefficient of Pb, Cd and Zn of Rhododendron were higher than that of Gramimeae. Enrichment coefficient of Pb, Cd and Zn were bush>tree>herbaceous, and herbaceous grew in soil with the highest concentrations of four heavy metals. In different areas, the concentrations of Pb, Cd, Cu and Zn in plants and soils and enrichment coefficient were different. Plants in Paomaping had more accumulating ability to Pb, Cd and Zn, and plants in Jinfeng River had more accumulating ability to Cu. Six plant species, i.e. S. cathayana, Lithocarpus dealbatus, L. plyneura, Fargesia dura, Arundinella yunnanensis and R. annae in Paomaping, had high accumulation capacity. R. annae in Paomaping had hyperaccumulating capacity to Pb, Cd and Zn, L. plyneura to Pb and Cd, and S. cathayana to Cd, respectively. PMID:15031017

  18. Multistage hydrothermal silicification and Fe-Tl-As-Sb-Ge-REE enrichment in the Red Dog Zn-Pb-Ag district, northern Alaska: Geochemistry, origin, and exploration applications

    USGS Publications Warehouse

    Slack, J.F.; Kelley, K.D.; Anderson, V.M.; Clark, J.L.; Ayuso, R.A.

    2004-01-01

    Geochemical analyses of major, trace, and rare earth elements (REE) in more than 200 samples of variably silicified and altered wall rocks, massive and banded sulfide, silica rock, and sulfide-rich and unmineralized barite were obtained from the Main, Aqqaluk, and Anarraaq deposits in the Red Dog Zn-Pb-Ag district of northern Alaska. Detailed lithogeochemical profiles for two drill cores at Aqqaluk display an antithetic relationship between SiO2/Al2O3 and TiO2/Zr which, together with textural information, suggest preferential silicification of carbonate-bearing sediments. Data for both drill cores also show generally high Tl, Sb, As, and Ge and uniformly positive Eu anomalies (Eu/Eu* > 1.0). Similar high Tl, Sb, As, Ge, and Eu/Eu* values are present in the footwall and shallow hanging wall of Zn-Pb-Ag sulfide intervals at Anarraaq but are not as widely dispersed. Net chemical changes for altered wall rocks in the district, on the basis of average Al-normalized data relative to unaltered black shales of the host Kuna Formation, include large enrichments (>50%) of Fe, Ba, Eu, V, S, Co, Zn, Pb, Tl, As, Sb, and Ge at both Red Dog and Anarraaq, Si at Red Dog, and Sr, U, and Se at Anarraaq. Large depletions (>50%) are evident for Ca at both Red Dog and Anarraaq, for Mg, P, and Y at Red Dog, and for Na at Anarraaq. At both Red Dog and Anarraaq, wall-rock alteration removed calcite and minor dolomite during hydrothermal decarbonation reactions and introduced Si, Eu, and Ge during silicification. Sulfidation reactions deposited Fe, S, Co, Zn, Pb, Tl, As, and Sb; barite mineralization introduced Ba, S, and Sr. Light REE and U were mobilized locally. This alteration and mineralization occurred during Mississippi an hydrothermal events that predated the Middle Jurassic-Cretaceous Brookian orogeny. Early hydrothermal silicification at Red Dog took place prior to or during massive sulfide mineralization, on the basis of the dominantly planar nature of Zn-Pb veins, which suggests

  19. (Mg,Pb)Sr 2(Y,Ca)Cu 2O 7, a new 60 K superconductor in the Pb-1:2:1:2 family

    NASA Astrophysics Data System (ADS)

    Liu, H. B.; Morris, D. E.; Sinha, A. P. B.

    1993-01-01

    (Mg,Pb)Sr 2(Y,Ca)Cu 2O 7, a new superconductor in the Pb-1:2:1:2 family, has been synthesized. The Y:Ca ratio and annealing conditions (oxygen pressure/temperature) have been optimized. Addition of silver oxide aids in increasing the superconducting volume fraction and raising Tc to 60 K. Since this Tc is comparable to that of other Pb-1:2:1:2 compounds, it is unlikely that Mg 2+ replaces Cu in the CuO 2 planes, in spite of its small radius ( r=0.72 Å); in that case a substantial depression of Tc would be expected. Instead, Mg 2+ appears to go into the PbO layer in a rock-salt surrounding, in analogy with other divalent elements.

  20. Valorization of biosorbent obtained from a forestry waste: Competitive adsorption, desorption and transport of Cd, Cu, Ni, Pb and Zn.

    PubMed

    Cutillas-Barreiro, Laura; Paradelo, Remigio; Igrexas-Soto, Alba; Núñez-Delgado, Avelino; Fernández-Sanjurjo, María José; Álvarez-Rodriguez, Esperanza; Garrote, Gil; Nóvoa-Muñoz, Juan Carlos; Arias-Estévez, Manuel

    2016-09-01

    Bark from Pinus pinaster is one of the most abundant forestry wastes in Europe, and among the proposed technologies for its reutilization, the removal of heavy metals from wastewater has been gaining increasing attention. In this work, we have studied the performance of pine bark for heavy metal biosorption on competitive systems. Pb, Cu, Ni, Zn and Cd sorption and desorption at equilibrium were studied in batch experiments, whereas transport was studied in column experiments. Batch experiments were performed adding simultaneously different concentrations (0.08-3.15mM) of two or more metals in solution to pine bark samples. Column experiments were performed with 10mM solutions of two metals or a 5mM solution of the five metals. In general, the results under competitive conditions were different to those obtained in monoelemental experiments. The multi-metal batch experiments showed the adsorption sequence Pb≈Cu>Cd>Zn>Ni for lower metal doses, Pb>Cu>Cd>Zn>Ni for intermediate doses, and Pb>Cu>Cd≈Zn≈Ni for high metal doses. Desorption followed the sequence PbPbCu and Pb suffered the highest retention, with high capacity to displace Cd, Ni and Zn from adsorption sites on pine bark. The transport experiments produced comparable results to those obtained in the batch experiments, with pine bark retention capacity following the sequence Pb>Cu>Zn>Cd>Ni. The presence of a second metal affected the transport of all the elements studied except Pb, and confirmed the strong influence of Pb and Cu on the retention of the other metals. These results can help to appropriately design decontamination systems using this forestry waste. PMID:27232204

  1. Immobilization of Cu, Pb and Zn in mine-contaminated soils using reactive materials.

    PubMed

    Navarro, Andrés; Cardellach, Esteve; Corbella, Mercé

    2011-02-28

    Immobilization processes were used to chemically stabilize soil contaminated with Cu, Pb and Zn from mine tailings and industrial impoundments. We examined the effectiveness of ordinary Portland cement (OPC), phosphoric acid and MgO at immobilizing Cu, Pb and Zn in soil contaminated by either mine tailings or industrial and mine wastes. The effectiveness was evaluated using column leaching experiments and geochemical modelling, in which we assessed possible mechanisms for metal immobilization using PHREEQC and Medusa numerical codes. Experimental results showed that Cu was mobilized in all the experiments, whereas Pb immobilization with H(3)PO(4) may have been related to the precipitation of chloropyromorphite. Thus, the Pb concentrations of leachates of pure mining and industrial contaminated soils (32-410 μg/l and 430-1000 μg/l, respectively) were reduced to 1-60 and 3-360 μg/l, respectively, in the phosphoric acid experiment. The mobilization of Pb at high alkaline conditions, when Pb(OH)(4)(-) is the most stable species, may be the main obstacle to the use of OPC and MgO in the immobilization of this metal. In the mining- and industry-contaminated soil, Zn was retained by OPC but removed by MgO. The experiments with OPC showed the Zn decrease in the leachates of mining soil from 226-1960 μg/l to 92-121 μg/l. In the industrial contaminated soil, the Zn decrease in the leachates was most elevated, showing >2500 μg/l in the leachates of contaminated soil and 76-173 μg/l in the OPC experiment. Finally, when H(3)PO(4) was added, Zn was mobilized. PMID:21190796

  2. A thermodynamic model of nickel smelting and direct high-grade nickel matte smelting processes: Part II. distribution behaviors of Ni, Cu, Co, Fe, As, Sb, and Bi

    NASA Astrophysics Data System (ADS)

    Tan, Pengfu; Neuschütz, Dieter

    2001-04-01

    A thermodynamic model has been developed to predict the distribution behavior of Ni, Cu, Co, Fe, S, As, Sb, and Bi in nickel smelting and direct high-grade nickel matte smelting processes. The model has been validated by numerous experimental data and industrial data with a wide range of operating conditions. The effect of operating conditions on the distributions of Ni, Cu, Co, As, Sb, and Bi among the gas, matte, and slag phases has been investigated. It was found that the distribution behavior of Ni, Co, Cu, As, Sb, and Bi in the nickel smelting furnace depends on process parameters such as the smelting temperature, matte grade, oxygen enrichment, Fe/SiO2 ratio in the slag, Cu/Ni ratio in charge, and oil/air ratio. The parameters also have an influence on the behavior of Fe3O4 in the slag.

  3. Mechanisms of wear in single- and two-phase materials: Final report. [Cu, Pb, Al/sub 2/O/sub 3/, Pb borosilicate glass, SiC (Pb-Cu), (Pb-Al/sub 2/O/sub 3/), (glass-Cu), (glass-Al/sub 2/O/sub 3/)

    SciTech Connect

    Macmillan, N.H.

    1987-11-01

    A comparative study has been made of the rolling-tumbling-sliding wear and solid particle erosion behavior of four single-phase materials (Cu, Pb, Al/sub 2/O/sub 3/, and a lead borosilicate glass and of series of ductile-ductile (Pb-Cu), ductile-brittle (Pb-Al/sub 2/O/sub 3/), brittle-ductile (glass-Cu), and brittle-brittle (glass-Al/sub 2/O/sub 3/) composites prepared from them. The same irregularly shaped 600 ..mu..m WC-8 wt.% Co abrasive particles were used throughout this work. Additional erosion measurements have been made on Danto Koruntz, Abresist, and sintered ..cap alpha..-SiC, using similar particles. Some subtle influences of erosive particle wear are documented for the first time, and the inadequacy of the currently available theoretical models to describe the influence of microstructure on erosion is exposed. 77 refs., 154 figs.

  4. (Hg, Sb)Ba2Ca2Cu3O8+δ thick films on YSZ substrates

    NASA Astrophysics Data System (ADS)

    Li, J. Q.; Lam, C. C.; Peacock, G. B.; Hyatt, N. C.; Gameson, I.; Edwards, P. P.; Shields, T. C.; Abell, J. S.

    2000-02-01

    Superconducting thick films of (Hg, Sb)Ba2Ca2Cu3O8+icons/Journals/Common/delta" ALT="delta" ALIGN="MIDDLE"/> have been fabricated on polycrystalline yttria-stabilized-zirconia substrates utilizing an Hg-free precursor film reacted with Hg vapour, released from a solid Hg source, in a sealed quartz tube. The resulting films have been studied by x-ray diffraction, scanning electron microscopy, ac susceptibility and resistance measurement techniques. A high quality Hg(Sb)-1223 superconducting thick film on YSZ can be fabricated by using a pre-melted Hg-free precursor film. The zero resistance superconducting transition temperature in the post-growth oxygenated thick film is in excess of 130 K and the transport critical current density for the film is 510 A cm-2 at 77 K.

  5. Synthesis and characterization of (1-x)Bi(Mg2/3Sb1/3)O3-xPbTiO3 piezoceramics

    NASA Astrophysics Data System (ADS)

    Upadhyay, Ashutosh; Dwivedi, Saurabh; Pandey, Rishikesh; Singh, Akhilesh Kumar

    2016-05-01

    We present here the comprehensive x-ray diffraction and polarization-electric field hysteresis studies on (1-x)Bi(Mg2/3Sb1/3)O3-xPbTiO3 piezoceramics with x = 0.52, 0.56 and 0.60. The powder x-ray diffraction data reveals the presence of tetragonal phase for all the compositions. The saturation of hysteresis loop is observed for x ≤ 0.56.

  6. Possible Mesozoic age of Ellenville Zn-Pb-Cu(Ag) deposit, Shawangunk Mountains, New York

    USGS Publications Warehouse

    Friedman, J.D.; Conrad, J.E.; McKee, E.H.; Mutschler, F.E.; Zartman, R.E.

    1994-01-01

    Ore textures, epithermal open-space filling of Permian structures of the Alleghanian orogeny, and largely postorogenic mineralization of the Ellenville, New York, composite Zn-Pb-Cu(Ag) vein system, provide permissive evidence for post-Permian mineralization. Isochron ages determined by 40Ar/39Ar laser-fusion techniques for K-bearing liquid inclusions in main-stage quartz from the Ellenville deposit additionally suggest a Mesozoic time of mineralization, associated with extensional formation of the Newark basin. The best 40Ar/39Ar total-fusion age range is 165 ?? 30 to 193 ?? 35 Ma. The Mesozoic 40Ar/39Ar age agrees with that of many other dated northern Appalachian Zn-Pb-Cu(Ag) deposits with near-matching lead isotope ratios, and adds new evidence of Jurassic tectonism and mineralization as an overprint to Late Paleozoic tectonism at least as far north as Ellenville (lat. 41??43???N). ?? 1994 Springer-Verlag.

  7. Pollution, fractionation, and mobility of Pb, Cd, Cu, and Zn in garden and paddy soils from a Pb/Zn mining area.

    PubMed

    Lei, Ming; Zhang, Yong; Khan, Sardan; Qin, Pu-feng; Liao, Bo-han

    2010-09-01

    This study was conducted to investigate the pollution load index, fraction distributions, and mobility of Pb, Cd, Cu, and Zn in garden and paddy soils collected from a Pb/Zn mine in Chenzhou City, China. The samples were analyzed using Leleyter and Probst's sequential extraction procedures. Total metal concentrations including Pb, Cd, Cu, and Zn exceeded the maximum permissible limits for soils set by the Ministry of Environmental Protection of China, and the order of the pollution index was Cd > Zn > Pb > Cu, indicating that the soils from both sites seriously suffered from heavy metal pollution, especially Cd. The sums of metal fractions were in agreement with the total contents of heavy metals. However, there were significant differences in fraction distributions of heavy metals in garden and paddy soils. The residual fractions of heavy metals were the predominant form with 43.0% for Pb, 32.3% for Cd, 33.5% for Cu, and 44.2% for Zn in garden soil, while 51.6% for Pb, 40.4% for Cd, 40.3% for Cu, and 40.9% for Zn in paddy soil. Furthermore, the proportions of water-soluble and exchangeable fractions extracted by the selected analytical methods were the lowest among all fractions. On the basis of the speciation of heavy metals, the mobility factor values of heavy metals have the following order: Cd (25.2-19.8%) > Cu (22.6-6.3%) > Zn (9.6-6.0%) > Pb (6.7-2.5%) in both contaminated soils. PMID:19669583

  8. Chemical immobilization of Pb, Cu, and Cd by phosphate materials and calcium carbonate in contaminated soils.

    PubMed

    Huang, Guoyong; Su, Xiaojuan; Rizwan, Muhammad Shahid; Zhu, Yifei; Hu, Hongqing

    2016-08-01

    Soil contamination with toxic metals has increasingly become a global concern over the past few decades. Phosphate and carbonate compounds are good passivation materials for Pb immobilization, while the effect of phosphate and carbonate on the immobilization of multiple heavy metals (Pb, Cu, and Cd) in contaminated soils was seldom investigated. In this study, bone meal (BM), phosphate rock (PR), oxalic acid-activated phosphate rock (APR), super phosphate (SP), and calcium carbonate (CC) were added to the contaminated soils to evaluate the effect of phosphate materials and calcium carbonate on the immobilization of Pb, Cu, and Cd. The results showed that the pH of the treated soils increased 1.3-2.7, except SP which decreased 0.5 at most. Compared to the control treatment, all phosphates and calcium carbonate added to the polluted soils increased the fraction of residual metals, and the application of APR, PR, BM, and CC significantly reduced exchangeable and carbonate-bound fraction metals. PR and APR were the most effective for the immobilization of Pb, Cu, and Cd in the soils among these materials. Moreover, the concentrations of all metals in the toxicity characteristic leaching procedure (TCLP) leachate decreased with increasing amounts of amendments, and the concentrations of Pb in the TCLP leachate for soils treated with PR and APR were below the nonhazardous regulatory limit of 5 mg L(-1) (US Environmental Protection Agency). Based on our results, phosphate rock and oxalic acid-activated phosphate rock are effective in the immobilization of multiple metals by reducing their mobility in the co-contaminated soils. PMID:27197655

  9. Leaching potential of pervious concrete and immobilization of Cu, Pb and Zn using pervious concrete

    NASA Astrophysics Data System (ADS)

    Solpuker, U.; Sheets, J.; Kim, Y.; Schwartz, F. W.

    2014-06-01

    This paper investigates the leaching potential of pervious concrete and its capacity for immobilizing Cu, Pb and Zn, which are common contaminants in urban runoff. Batch experiments showed that the leachability of Cu, Pb and Zn increased when pH < 8. According to PHREEQC equilibrium modeling, the leaching of major ions and trace metals was mainly controlled by the dissolution/precipitation and surface complexation reactions, respectively. A 1-D reactive transport experiment was undertaken to better understand how pervious concrete might function to attenuate contaminant migration. A porous concrete block was sprayed with low pH water (pH = 4.3 ± 0.1) for 190 h. The effluent was highly alkaline (pH ~ 10 to 12). In the first 50 h, specific conductance and trace-metal were high but declined towards steady state values. PHREEQC modeling showed that mixing of interstitial alkaline matrix waters with capillary pore water was required in order to produce the observed water chemistry. The interstitial pore solutions seem responsible for the high pH values and relatively high concentrations of trace metals and major cations in the early stages of the experiment. Finally, pervious concrete was sprayed with a synthetic contaminated urban runoff (10 ppb Cu, Pb and Zn) with a pH of 4.3 ± 0.1 for 135 h. It was found that Pb immobilization was greater than either Cu or Zn. Zn is the most mobile among three and also has the highest variation in the observed degree of immobilization.

  10. Leaching potential of pervious concrete and immobilization of Cu, Pb and Zn using pervious concrete.

    PubMed

    Solpuker, U; Sheets, J; Kim, Y; Schwartz, F W

    2014-06-01

    This paper investigates the leaching potential of pervious concrete and its capacity for immobilizing Cu, Pb and Zn, which are common contaminants in urban runoff. Batch experiments showed that the leachability of Cu, Pb and Zn increased when pH<8. According to PHREEQC equilibrium modeling, the leaching of major ions and trace metals was mainly controlled by the dissolution/precipitation and surface complexation reactions, respectively. A 1-D reactive transport experiment was undertaken to better understand how pervious concrete might function to attenuate contaminant migration. A porous concrete block was sprayed with low pH water (pH=4.3±0.1) for 190 h. The effluent was highly alkaline (pH~10 to 12). In the first 50 h, specific conductance and trace-metal were high but declined towards steady state values. PHREEQC modeling showed that mixing of interstitial alkaline matrix waters with capillary pore water was required in order to produce the observed water chemistry. The interstitial pore solutions seem responsible for the high pH values and relatively high concentrations of trace metals and major cations in the early stages of the experiment. Finally, pervious concrete was sprayed with a synthetic contaminated urban runoff (10 ppb Cu, Pb and Zn) with a pH of 4.3±0.1 for 135 h. It was found that Pb immobilization was greater than either Cu or Zn. Zn is the most mobile among three and also has the highest variation in the observed degree of immobilization. PMID:24748027

  11. Study of Pb-doped Ge{sub 2}Sb{sub 2}Te{sub 5} in crystalline phase using first principle calculations

    SciTech Connect

    Singh, Janpreet; Tripathi, S. K. E-mail: surya-tr@yahoo.com; Singh, Gurinder; Kaura, Aman

    2015-08-28

    To improve the phase change characteristics of Ge{sub 2}Sb{sub 2}Te{sub 5} (GST), doping is used as one of the effective methods. 4.4 atomic % of Pb doped GST has been studied using first principle calculations. No effect of doping on Te-Ge and Te-Sb bond length has been observed, but the Te-Te bond gets shrink with Pb doping. Due to which the Sb{sub 2}Te{sub 3} segregates as a second phase, with increased doping concentration of Pb in GST alloy. Using such type of calculation, we can calculate the desirable concentration of dopant atoms to prepare the desired material. We can control any segregation in required material with pre-theoretical calculations. The metallic nature of Pd doped GST has been discussed with band structure plots. The metallic character of alloys calculated as in this paper will be helpful to understand the tuning of conductivity of phase change materials, which helps to enhance the phase change properties.

  12. Density Functional Study of the magnetic structure on spin frustrated MnSb2 S 4 and Sr2 MOsO 6 (M = Cu, Ni)

    NASA Astrophysics Data System (ADS)

    Tian, Chuan; Lee, Changhoon; Kan, Erjun; Wu, Fang; Whangbo, Mike

    2011-03-01

    We explored the electronic structures of two spin-frustrated magnetic systems monoclinic MnSb 2 S4 and Sr 2 MOs O6 (M = Cu, Ni) on the basis of first principles DFT calculations. The spin exchanges of MnSb 2 S4 are frustrated within each Mn S4 chain and between adjacent Mn S4 chains, which explains the observed helical spin order of MnSb 2 S4 . We predict that MnSb 2 S4 is multiferroic with ferroelectric polarization of ~ 14 μ C/ m 2 along the chain direction, and a field-induced reversal of the ferroelectric polarization occurs by reversing the direction of the helical spin rotation. The ordered double perovskites Sr 2 MOs O6 (M = Cu, Ni), reported to be half-metallic, are found to be magnetic insulators. The magnetic structures of Sr 2 MOs O6 were probed by evaluating their spin exchanges.

  13. Synthesis, crystal and electronic structure of the quaternary sulfides Ln2CuMS5 (Ln=La, Ce; M=Sb, Bi)

    NASA Astrophysics Data System (ADS)

    Kussainova, Ardak M.; Akselrud, Lev G.; Suen, Nian-Tzu; Voss, Leonard; Stoyko, Stanislav; Bobev, Svilen

    2016-01-01

    The series of quaternary sulfides with general formula Ln2CuMS5 (Ln=La, Ce; M=Sb, Bi) have been synthesized by solid-state reactions. Three representative members have been structurally characterized by single-crystal X-ray diffraction. La2CuSbS5 crystallizes in a new structure type (space group Ima2 (no. 46), Z=4, a=13.401(2) Å, b=7.592(1) Å, c=7.598(1) Å, V=773.1(3) Å3). The bismuth analogs of composition La2CuBiS5 and Ce2CuBiS5 crystallize with the La2CuInSe5 structure type (space group Pnma (no. 62), Z=4). Lattice parameters for La2CuBiS5: a=11.9213(5) Å, b=3.9967(2) Å, c=17.0537(8) Å, V=812.56(7) Å3; lattice parameters for Ce2CuBiS5: a=11.9179(15) Å, b=3.9596(5) Å, c=16.955(2) Å, V=800.13(17) Å3). The similarities and the differences between the two structures are discussed. Electronic structure calculations for La2CuSbS5 and La2CuBiS5 are also presented; they suggest semiconducting behavior with energy gaps exceeding 1.7 eV.

  14. Interactions of aqueous Cu2+, Zn2+ and Pb2+ ions with crushed concrete fines.

    PubMed

    Coleman, Nichola J; Lee, William E; Slipper, Ian J

    2005-05-20

    The crushing of reclaimed concrete-based demolition waste to produce recycled aggregate gives rise to a large volume of cement-rich fine material for which market development would be beneficial. It was envisaged that this fine fraction may prove to be an effective sorbent for aqueous heavy metal species by virtue of its ion exchangeable phases and high pH. A batch sorption study confirmed that crushed concrete, in the particle size range 1-2 mm, successfully excluded Cu2+ (35 mg g(-1)), Zn2+ (33 mg g(-1)) and Pb2+ (37 mg g(-1)) from aqueous media. Subsequent distilled water leaching of the metal-laden concrete particles indicated that 1.9, 0.9 and 0.2% of the bound metals, Cu2+, Zn2+ and Pb2+, respectively, were readily soluble. Scanning electron microscopy revealed that the removal of Cu2+ and Zn2+ arose from surface precipitation reactions, whereas, the principal mechanism of uptake of Pb2+ was found to be by diffusion into the cement matrix. The metal ion removal efficiency of crushed concrete fines is compared with those of other low cost sorbents and potential applications which may exploit this sorptive property are also discussed. PMID:15885423

  15. Determination of Zn, Pb, Cu, and Hg in soils of Ekpan, Nigeria

    SciTech Connect

    Omgbu, J.A.; Kokogho, M.A. )

    1993-01-01

    The concentrations of zinc, lead, copper, and mercury in solids in Ekpan were determined in order to assess the impact of petroleum-refining activities. Twenty soil samples were collected 100 m apart (10 topsoils 0 to 15 cm and 10 bottom soils 15 to 30 cm). Sample solutions prepared were analyzed using the atomic absorption spectrophotometry technique. Results show that top-soil samples contain as much as 7.13 to 13.10 [mu]g/g Zn, 55.13 to 65.50 [mu]g/g Pb, 3.47 to 5.27 [mu]g/g Cu, and 4.00 to 6.50 [mu]g.g Hg. Bottom soil samples contain as much as 7.17 to 13.77 [mu]g/g Zn, 54.97 to 63.23 [mu]g/g Pb, 3.57 to 6.50 [mu]/g Cu, and 4.57 to 6.63 [mu]g/g Hg. The levels reported had an abundance ratio in the order Pb > Zn > Hg > Cu in the soil samples. It is recommended that appropriate measures be put in place by the companies to treat waste effluent before discharging them to the immediate environment. 8 refs., 2 tabs.

  16. Pb, Cu and Cd distribution in five estuary systems of Marche, central Italy.

    PubMed

    Annibaldi, Anna; Illuminati, Silvia; Truzzi, Cristina; Libani, Giulia; Scarponi, Giuseppe

    2015-07-15

    Heavy metals are subjected to monitoring in estuarine and marine water by the European Union Water Framework Directive, which requires water body health to be achieved by 2021. This is the first survey of heavy metals content in five estuaries of Marche, a region in central Italy. Results showed that total Pb and Cu concentrations decreased by 70-80%, from 1000-2000 to 100-200 ng L(-1) (Pb) and from 2000-3000 to 500-1000 ng L(-1) (Cu) from river to sea. Cd was consistently 20-40 ng L(-1). Dissolved Pb and Cu concentrations declined by 50% and 70% respectively passing from oligohaline to euhaline water, from 150 to 70 ng L(-1) and from 2000-1000 to 600-400 ng L(-1). Cd decreased slightly from ∼20 to ∼10 ng L(-1). Although such concentrations are in the range allowed by the Water Framework Directive, they far exceed (up to 10×) the ground content ceiling set for 2021. PMID:25960271

  17. Particulate contacts to Si and CdTe: Al, Ag, Hg-Cu-Te, and Sb-Te

    NASA Astrophysics Data System (ADS)

    Schulz, Douglas L.; Ribelin, Rosine; Curtis, Calvin J.; Ginley, David S.

    1999-03-01

    Our team has been investigating the use of particle-based contacts in both Si and CdTe solar cell technologies. First, in the area of contacts to Si, powders of Al and Ag prepared by an electroexplosion process have been characterized by transmission electron microscopy (TEM), TEM elemental determination X-ray spectroscopy (TEM-EDS), and TEM electron diffraction (TEM-ED). These Al and Ag particles were slurried and tested as contacts to p- and n-type silicon wafers, respectively. Linear current-voltage (I-V) was observed for Ag on n-type Si, indicative of an ohmic contact, whereas the Al on p-type Si sample was non-ideal. A wet-chemical surface treatment was performed on one Al sample and TEM-EDS indicated a substantial decrease in the O contaminant level. The treated Al on p-type Si films exhibited linear I-V after annealing. Second, in the area of contacts to CdTe, particles of Hg-Cu-Te and Sb-Te have been applied as contacts to CdTe/CdS/SnO2 heterostructures prepared by the standard NREL protocol. First, Hg-Cu-Te and Sb-Te were prepared by a metathesis reaction. After CdCl2 treatment and NP etch of the CdTe layer, particle contacts were applied. The Hg-Cu-Te contacted cells exhibited good electrical characteristics, with Voc>810 mV and efficiencies > 11.5% for most cells. Although Voc>800 mV were observed for the Sb-Te contacted cells, efficiencies in these devices were limited to 9.1% presumably by a large series resistance (>20 Ω) observed in all samples.

  18. Grain growth behavior of Pb-Cu-Te cable sheathing alloys

    SciTech Connect

    Sahay, S.S.; Guruswamy, S.; Goodwin, F.

    1995-04-01

    Lead alloys are extensively used as sheathing material for power and telecommunication cables. Excellent extrusion properties, high ductility, extremely low recrystallization temperature, good fatigue and creep resistance, make these alloys ideal for cable sheathing application. Though the thickness of the lead sheath is only a few hundred {mu}m, it is a critical component of the cable. The lead layer in the cable is often the limiting factor both during the cable production and during its service phase. Up to several hundred miles of long single piece cables may be required for underground and underwater cables. Cracking in the lead sheath during the cable sheathing extrusion limits the production of such long cables while cracking of the lead sheath due to repeated vibration, creep and recrystallization limits the service life of these cables. The purpose of the present research is to increase the duration of cable extrusion time without compromising sheath integrity by minimizing deleterious precipitate formation and growth. Concentrations of Cu and Te in the commercial alloy are too small to contribute to precipitation strengthening. Therefore their positive influence on mechanical strength should mainly result from the influence of Cu and Te in solution on interdiffusivity and grain boundary mobility. The formation of large precipitates observed in Pb-Cu-Te alloys can be minimized and extrusion times increased without negatively affecting mechanical properties if the solute content is reduced to near solid solubility levels. In order to examine the effect of lowering solute content on microstructural stability and mechanical properties, compressive stress-strain behavior of a Pb-50 wt ppm Cu-100 wt ppm Te alloy with solute contents close to the solubility limits and a Pb-400 wt ppm Cu-400 wt ppm Te alloy was examined at room temperature. The grain growth kinetics in these alloys were studied in a temperature range of 100 to 225 C.

  19. Influence of IMC in the Semisolid Behaviour of an Eutectic Sn-Pb/Cu Slurry

    SciTech Connect

    Merizalde, Carlos; Cabrera, Jose-Maria; Prado, Jose-Manuel

    2007-04-07

    A mixture of a liquid Sn-Pb alloy reinforced with solid Cu particles has been found to show thixotropic and pseudoplastic behaviour. The presence of an intermetallic compound (IMC) between the Cu particles and the molten matrix has some very important consequences in the rheological behaviour of the slurry. The semisolid material is obtained mixing a sufficient amount of Cu particles with a liquid eutectic Sn-Pb alloy by mechanical stirring at a given temperature and time. The intermetallic compound is formed from the reaction of solid Cu and liquid Sn. This reaction results in some displacement in the phase diagram, affecting the liquid alloy composition, moving the liquidus temperature and therefore altering the balance of %wt solid- %wt liquid necessary to obtain the best thixotropic behaviour. In this work a model of the solid fraction of the slurry taking into account the IMC growth rate is presented. This model is also used to predict the processing window under which the material keeps the thixotropic behaviour.

  20. Cu induced morphology changes at Pb/Si (1 1 1) interface: Separation of “5 × 5”-Cu structure into individual domains

    NASA Astrophysics Data System (ADS)

    Shukrynau, Pavel; Mutombo, Pingo; Hietschold, Michael; Cháb, Vladimír

    2013-04-01

    The adsorption of small amount of Cu onto 1 × 1-Pb/Si (1 1 1) and √3 × √3R30°-Pb/Si (1 1 1) coexisting phases was studied with variable temperature scanning tunnelling microscopy and spectroscopy. The most significant features connected with the deposition of copper at room temperature appeared as tiny clusters randomly scattered over smooth 1 × 1-Pb islands. Behaviour of the clusters at room at low temperature assumed that Cu penetrates through inert 1 × 1-Pb layer and mixes up with silicon. Moderate thermal treatment of (Cu, Pb)/Si (1 1 1) system induced the formation of shallow depressions of variable shape and size that are embedded into 1 × 1-Pb phase. Tunnelling spectra taken over a particular depression showed the peaks typical for the copper silicides. Moreover, the temperature rise causes the formation of large objects of distinctive hexagonal shape on neighbouring √3 × √3R30°-Pb/Si (1 1 1) structure. Filled and empty state STM images of the hexagons differ strongly suggesting covalent bonding between constituent atoms. Detailed analysis of the hexagonal objects (and their agglomerates) reveals the specific features of quasi-commensurate 5 × 5-Cu structure.

  1. Crystalline style and tissue redistribution in Perna viridis as indicators of Cu and Pb bioavailabilities and contamination in coastal waters.

    PubMed

    Yap, C K; Ismail, A; Cheng, W H; Tan, S G

    2006-03-01

    The concentrations of Cu, Pb, and Zn in the crystalline style (CS) and in the remaining soft tissues (ST) of the green-lipped mussel Perna viridis from 10 geographical sites along the coastal waters off peninsular Malaysia were determined. The CS, compared with the remaining ST, accumulated higher levels of Cu in both contaminated and uncontaminated samples, indicating that the style has a higher affinity for the essential Cu to bind with metallothioneins. The similar pattern of Cu accumulation in the different ST of mussels collected from clean and Cu-contaminated sites indicated that the detoxification capacity of the metallothioneins had not been overloaded. For Pb, higher levels of the metal in the CS than in the remaining ST were found only in mussels collected from a contaminated site at Kg. Pasir Puteh. This indicated a tissue redistribution of Pb due to its binding to metallothioneins for Pb detoxification and the potential of the CS as an indicator organ of Pb bioavailability and contamination. For Zn, the above two phenomena were not found since no obvious patterns were observed (lower levels of Zn in the CS than in the remaining ST) in contaminated and uncontaminated samples due to the mechanism of partial regulation. Generally, all the different STs studied (foot, mantle, gonad, CS, gill, muscle, and byssus) are good biomonitoring tissues for Cu and Pb bioavailabilities and contamination. Among these organs, the CS was found to be the best organ for biomonitoring Cu. The present data also suggest the use of the tissue redistribution of Pb in P. viridis as an indicator of Pb bioavailability and contamination in coastal waters. PMID:16406592

  2. Spectral analysis of Cu(2+): B(2)O(3)--ZnO--PbO glasses.

    PubMed

    Lakshminarayana, G; Buddhudu, S

    2005-11-01

    A new series of heavy metal oxide (PbO) based zinc borate glasses in the chemical composition of (95-x)B(2)O(3)-5ZnO-xPbO (x=10, 15, 20, 25, 30, 35, 40, 45 and 50 mol%) have been prepared to verify their UV filtering performance. Both direct and indirect optical band gaps (E(opt)) have been evaluated for these glasses. For a reference glass of 45B(2)O(3)-5ZnO-50PbO, refractive indices at different wavelengths are measured and found the results satisfactorily correlated with the theoretical data upon the computation of Cauchy's constants of A=1.766029949, B=159531.024 nm(2) and C=-1.078 x 10(10) nm(4). Measurements concerning X-ray diffraction (XRD), FT-IR, differential scanning colorimeter (DSC) profiles have been carried out for this glass. The FT-IR profile has revealed that the glass has both BO(3) and BO(4) units. From DSC thermogram, glass transition temperature (T(g)), crystallization temperature (T(c)) and melting temperature (T(m)) have been located and from them, other related parameters of the glass have also been calculated. Visible absorption spectra of 45B(2)O(3)-5ZnO-(50-x)PbO-xCuO (x=0. 1, 0.2, 0.5 and 1.0 mol%) have revealed two absorption bands at around 400 nm ((2)B(1g)-->(2)E(g)) and 780 nm ((2)B(1g)-->(2)B(2g)) of Cu(2+) ions, respectively. Emission bands at 422 and 512 nm are found for the 1 mol % CuO doped glass with excitations at 306 and 332 nm. PMID:16257737

  3. Stabilization of As, Cr, Cu, Pb and Zn in soil using amendments--a review.

    PubMed

    Kumpiene, Jurate; Lagerkvist, Anders; Maurice, Christian

    2008-01-01

    The spread of contaminants in soil can be hindered by the soil stabilization technique. Contaminant immobilizing amendments decrease trace element leaching and their bioavailability by inducing various sorption processes: adsorption to mineral surfaces, formation of stable complexes with organic ligands, surface precipitation and ion exchange. Precipitation as salts and co-precipitation can also contribute to reducing contaminant mobility. The technique can be used in in situ and ex situ applications to reclaim and re-vegetate industrially devastated areas and mine-spoils, improve soil quality and reduce contaminant mobility by stabilizing agents and a beneficial use of industrial by-products. This study is an overview of data published during the last five years on the immobilization of one metalloid, As, and four heavy metals, Cr, Cu, Pb and Zn, in soils. The most extensively studied amendments for As immobilization are Fe containing materials. The immobilization of As occurs through adsorption on Fe oxides by replacing the surface hydroxyl groups with the As ions, as well as by the formation of amorphous Fe(III) arsenates and/or insoluble secondary oxidation minerals. Cr stabilization mainly deals with Cr reduction from its toxic and mobile hexavalent form Cr(VI) to stable in natural environments Cr(III). The reduction is accelerated in soil by the presence of organic matter and divalent iron. Clays, carbonates, phosphates and Fe oxides were the common amendments tested for Cu immobilization. The suggested mechanisms of Cu retention were precipitation of Cu carbonates and oxy-hydroxides, ion exchange and formation of ternary cation-anion complexes on the surface of Fe and Al oxy-hydroxides. Most of the studies on Pb stabilization were performed using various phosphorus-containing amendments, which reduce the Pb mobility by ionic exchange and precipitation of pyromorphite-type minerals. Zn can be successfully immobilized in soil by phosphorus amendments and clays

  4. Decrease and increase profile of Cu, Cr and Pb during stable phase of removal by duckweed (Lemna minor L.).

    PubMed

    Uçüncü, Esra; Tunca, Evren; Fikirdeşici, Seyda; Altindağ, Ahmet

    2013-01-01

    The present work details the decrease-increase profiles of Cu, Cr, and Pb by the aquatic plant Lemna minor. A mixture of these metals were utilized at different concentrations. Removal profiles of each metal was determined with water samples taken every 24 h for a 144 h period after the 48 h mark and was examined with correlation analysis. Removal profiles of Cr and Pb by L. minor from the mixture were observed to be highly similar with each other (r = 0.943). High proportion of Cr and Pb were removed compared to Cu and removal equations were defined with the aid of regression analysis. PMID:23488003

  5. Direct detection of Pb in urine and Cd, Pb, Cu, and Ag in natural waters using electrochemical sensors immobilized with DMSA functionalized magnetic nanoparticles

    SciTech Connect

    Yantasee, Wassana; Hongsirikarn, Kitiya; Warner, Cynthia L.; Choi, Daiwon; Sangvanich, Thanapon; Toloczko, Mychailo B.; Warner, Marvin G.; Fryxell, Glen E.; Addleman, Raymond S.; Timchalk, Chuck

    2008-03-01

    Urine is universally recognized as one of the best non-invasive matrices for biomonitoring exposure to a broad range of xenobiotics including toxic metals. For direct, simple, and field-deployable monitoring of urinary Pb, electrochemical sensors employing superparamagnetic iron oxide (Fe3O4) nanoparticles with a surface functionalization of dimercaptosuccinic acid (DMSA) has been developed. The metal detection involves rapid collection of dispersed metal-bound nanoparticles from a sample solution at a magnetic or electromagnetic electrode, followed by the stripping voltammetry of the metal in acidic medium. The sensors were evaluated as a function of solution pH, the binding affinity of Pb to DMSA-Fe3O4, the ratio of nanoparticles per sample volume, preconcentration time, and Pb concentrations. The effect of binding competitions between the DMSA-Fe3O4 and urine constituents for Pb on the sensor responses was studied. After 90s of preconcentration in samples containing 25 vol.% of rat urine and 0.1 g/L of DMSA-Fe3O4, the sensor could detect background level of Pb (< 1 ppb) and yielded linear responses from 0 to 50 ppb of Pb, excellent reproducibility (%R.S.D of 5.3 for seven measurements of 30 ppb Pb), and Pb concentrations comparable to those measured by ICP-MS. The sensor could also simultaneously detect background levels (< 1 ppb) of Cd, Pb, Cu, and Ag in river and seawater.

  6. Is increasing industrialization affecting remote ecosystem health in the South Americas? Insights from ocean surface water measurements of As, Sb and Pb from a GEOTRACES transect

    NASA Astrophysics Data System (ADS)

    Weiss, Dominik; Salaun, Pascal; Van den Berg, Stan; Bi, Zaoshun

    2014-05-01

    Continued industrial development of the South Americas with increasing atmospheric emission of toxic trace metals has lead to a growing concern about possible effects on pristine ecosystem health. Concentration measurements of trace metals in ocean surface waters in the North Atlantic have successfully revealed the global extent of atmospheric pollution in the Northern Hemisphere during economical growth in the USA and Europe, suggesting a similar approach can be applied to the Southern Hemisphere. To this end, we determined concentrations of lead (Pb), antimony (Sb) and arsenic (As) using voltammetry in surface water samples of the South Atlantic Ocean collected during the third leg of the GEOTRACES West Atlantic Cruise. These elements are volatile and therefore most likely suitable tracer elements of industrial emissions from South America. The samples were not filtered and the solutions were acidified and UV digested. Total concentrations of Pb were detected. Detected As levels correspond to the sum of inorganic species (AsIII + AsV) plus the mono methyl arsenic acid (MMA) while the dimethyl arsenic acid (DMA) is not detected in such conditions. For Sb, detected levels correspond at least to the sum of inorganic fractions (SbIII + SbV). The measured concentrations for Pb varied from 6 to 23 pM. Concentrations were highest at -35° latitude and lowest at -40° and -50° latitude. We found a decreasing trend from about -35° latitude southwards. The average concentrations of As was 20 nM and of Sb 1.2 nM. Arsenic showed a more significant north to south trend than Sb. Arsenic concentration was highest at -23 ° latitude (21 nM) and the lowest at -43 ° latitude (17.7 nM). Antimony concentration was highest at -31 ° latitude (1.5 nM) and lowest at -35 ° latitude (1.0 nM). Our preliminary data suggests that the major industrial centres in Brazil (i.e., Sao Paolo, Rio de Janeiro) and Argentina (i.e., Buenos Aires) affect atmospheric metal fluxes to remote

  7. Speciation and mobility of Zn, Cu and Pb in a truck farming soil contaminated by sewage irrigation

    NASA Astrophysics Data System (ADS)

    Kirpichtchikova, T.; Manceau, A.; Lanson, B.; Marcus, M. A.; Jacquet, T.

    2003-05-01

    The forrns and mobility of Cu (290 mg/kg), Zn (1103 mg/kg), and Pb (535 mg/kg) in a soil used for intensive truck farining from the Region Ile-de-France, and which has been irrigated for more than a century with sewage water ftom the city of Paris, have been studied by chemical treatments and advanced x-ray techniques. Elemental associations and forms of metals were determined qualitatively and quantitatively by a combination of physical techniques, including μPIXE (Cu, Zn, Pb), μSXRF (Cu, Zn), μEXAFS (Zn) and powder EXAFS (Zn). The nature, number, and relative proportion of Zn species were obtained by principal component analysis and decomposition of Zn K-edge EXAFS spectra. These data collectively indicate that Cu is associated mainly with organic matter, and that Zn and Pb are bound essentially to mineral constituents. Four Zn-containing species were positively identified: Zn-phosphate and phyllosilicate as dominant species, and Zn-Fe oxyhydroxide and willemite (Zn2SiO4) as minor species. Studies are underway to determine the structural forms of Cu and Pb. Depending on the chemical treatment, up to 70% Cu, ~50% Zn, and ~85% Pb can be removed in a few days with citrate and EDTA. Citrate is generally at least as efficient as EDTA, and it has the advantage ofbeing easily biodegradable and, hence, less harmful to ecosystems.

  8. Heavy metal concentrations (Cd, Cu and Pb) in five aquatic plant species in Tasik Chini, Malaysia

    NASA Astrophysics Data System (ADS)

    Ebrahimpour, M.; Mushrifah, I.

    2008-04-01

    The purpose of this study was to determine the levels of heavy metals namely cadmium (Cd), copper (Cu) and lead (Pb) in the five aquatic plants. For this purpose, the concentration of heavy metals were measured in water and in the five aquatic plant species, Lepironia articulata, Pandanus helicopus, Scirpus grossus, Cabomba furcata and Nelumbo nucifera, in 15 sites from Tasik Chini. The concentrations were different among the plant species as well as among the parts of plants. The highest concentration of heavy metals among the aquatic plants and plant parts was found in the roots of S. grossus. The concentrations of Cd in the leaves and stems of submerged aquatic plant, C . furcata, were higher than concentration of Cd in the leaves and stems of emergent aquatic plant and floating leaf plant. The concentration of Cu in the stem of C. furcata was greater than that in the leaf, while the concentration of Cd was more in the leaf than in the stem. The heavy metal contents of the aquatic plants were in descending order of Pb > Cu > Cd. The metal concentration quotient of leaves/roots and stems/roots (ML/MR and MS/MR) were calculated. The highest internal translocation was found in P. helicopus, while the lowest internal translocation was found in S. grossus.

  9. Atmospheric deposition of heavy metals (Cu, Zn, Cd and Pb) in Varanasi City, India.

    PubMed

    Sharma, Rajesh Kumar; Agrawal, Madhoolika; Marshall, Fiona M

    2008-07-01

    Rapid growth in urbanization and industrialization in developing countries may significantly contribute in heavy metal contamination of vegetables through atmospheric depositions. In the present study, an assessment was made to investigate the spatial and seasonal variations in deposition rates of heavy metals and its contribution to contamination of palak (Beta vulgaris). Samples of bulk atmospheric deposits and Beta vulgaris for analysis of Cu, Zn, Cd and Pb were collected from different sampling locations differing in traffic density and land use patterns. The results showed that the sampling locations situated in industrial or commercial areas with heavy traffic load showed significantly elevated levels of Cu, Zn and Cd deposition rate as compared to those situated in residential areas with low traffic load. The deposition rates of Cu, Zn and Cd were significantly higher in summer and winter as compared to rainy season, however, Pb deposition rate was significantly higher in rainy and summer seasons as compared to winter season. Atmospheric depositions have significantly elevated the levels of heavy metals in B. vulgaris collected during evening as compared to those collected in morning hours. The study further showed that local population has maximum exposure to Cd contamination through consumption of B. vulgaris. The present study clearly points out the urban and industrial activities of a city have potential to elevate the levels of heavy metals in the atmospheric deposits, which may consequently contaminate the food chain and thus posing health risk to the local population. PMID:17879134

  10. The interaction of Ag with Bi-Pb-Sr-Ca-Cu-O superconductor

    NASA Astrophysics Data System (ADS)

    Dou, S. X.; Song, K. H.; Liu, H. K.; Sorrell, C. C.; Apperley, M. H.; Gouch, A. J.; Savvides, N.; Hensley, D. W.

    1989-10-01

    Bi-Pb-Sr-Ca-Cu-O superconductor compounds have been doped with up to 30 wt% Ag, sintered under variable oxygen partial pressure, and characterised in terms of the electrical and crystallographic behaviour. In contrast to previous reports that claim that Ag is the only metal non-poisoning to the superconductivity of Bi-Sr-Ca-Cu-O (BSCCO), it has been found that Ag additions to Bi-Pb-Sr-Ca-Cu-O depress Tc and Jc drastically and cause a large decrease in lattice parameters when samples are treated in air or pure oxygen. However, the lattice parameters, Tc and Jc remain unaffected by Ag additions when samples are heat treated in 0.030-0.067 atm oxygen. It is clear that the Ag reacts with and destabilises the superconducting phase when the samples are treated in air or pure oxygen while, when the samples are heat treated in low oxygen partial pressures, the Ag remains as an isolated inert metal phase that improves the weak links between the grains. This discovery clearly shows the feasibility of Ag-clad superconductor wire. For Ag-clad superconductor tape of 0.1 mm 2 cross sectional area heat treated in air, Jc was measured to be 54 A/cm 2. The same specimen sintered in 0.067 atm oxygen showed that the Jc increased to 2078 A/cm 2.

  11. Improved charge transfer and photoelectrochemical performance of CuI/Sb2S3/TiO2 heterostructure nanotube arrays.

    PubMed

    Yang, Feng; Xi, Jinfang; Gan, Li-Yong; Wang, Yushu; Lu, Shuangwei; Ma, Wenli; Cai, Fanggong; Zhang, Yong; Cheng, Cuihua; Zhao, Yong

    2016-02-15

    Charge transfer is important for the performance of a photoelectrochemical cell. Understanding photogenerated charge accumulation and separation is mandatory for the design and optimisation of photoelectrochemical cells. Unique stacked and embedded heterostructure of Sb2S3/TiO2 nanotube arrays (NTAs) was fabricated through anodic oxidation with the hydrothermal method. Surface photovoltage spectroscopy, phase spectra and photoluminescence measurements were performed to explore the mechanism by which the inorganic hole transport material CuI affects the charge transfer and photoelectrochemical properties of Sb2S3/TiO2 heterostructure NTAs. The interfacial separation and transport of photoinduced charge carriers were also examined by applying current-voltage characteristics (J-V), incident-photon-to-current conversion efficiency (IPCE) and Mott-Schottky techniques. Results show that CuI acts not only as a hole-conducting and electron-blocking material but also as a light-absorbing material in the ultraviolet range. Efficient charge transfer processes exist in CuI/Sb2S3/TiO2 heterostructure NTAs. The photoelectrochemical performance of CuI/Sb2S3/TiO2 heterostructure NTAs is dramatically improved. Under AM 1.5G illumination at 100mW/cm(2), the short-circuit current density and open-circuit voltage are 3.51mA/cm(2) and 0.87V, respectively. The photoelectric conversion efficiency of CuI/Sb2S3/TiO2 heterostructure NTAs (0.95%) is 36% higher than that of Sb2S3/TiO2 heterostructure NTAs (0.66%). PMID:26598949

  12. Reduced Carrier Recombination in PbS - CuInS2 Quantum Dot Solar Cells

    PubMed Central

    Sun, Zhenhua; Sitbon, Gary; Pons, Thomas; Bakulin, Artem A.; Chen, Zhuoying

    2015-01-01

    Energy loss due to carrier recombination is among the major factors limiting the performance of TiO2/PbS colloidal quantum dot (QD) heterojunction solar cells. In this work, enhanced photocurrent is achieved by incorporating another type of hole-transporting QDs, Zn-doped CuInS2 (Zn-CIS) QDs into the PbS QD matrix. Binary QD solar cells exhibit a reduced charge recombination associated with the spatial charge separation between these two types of QDs. A ~30% increase in short-circuit current density and a ~20% increase in power conversion efficiency are observed in binary QD solar cells compared to cells built from PbS QDs only. In agreement with the charge transfer process identified through ultrafast pump/probe spectroscopy between these two QD components, transient photovoltage characteristics of single-component and binary QDs solar cells reveal longer carrier recombination time constants associated with the incorporation of Zn-CIS QDs. This work presents a straightforward, solution-processed method based on the incorporation of another QDs in the PbS QD matrix to control the carrier dynamics in colloidal QD materials and enhance solar cell performance. PMID:26024021

  13. Concentrations of Pb, Zn, and Cu in Taraxacum spp. in relation to urban pollution

    SciTech Connect

    Cook, C.M.; Lanaras, T.; Sgardelis, S.P.; Pantis, J.D. )

    1994-08-01

    The combustion of petroleum fuel and exhaust emissions are major sources of atmospheric pollution in cities which result in the deposition of toxic substances, particularly heavy metals, in the surface layers of soils. Lead in particular enters the environment from the use of tetraethyl lead as an antiknock agent for petrol engines constituting 21% of fine particles emitted from cars burning leaded petrol. Antiwear protectants incorporated in lubricants often contain Cd, Cr, Cu, Hg, Ni, Pb and/or Zn which are also released into the environment by inefficient engines and irresponsible dumping of engine oils. Zn from tyre wear and Cu from diesel engines also add considerably to the environmental metal burden. Lowering of the permitted lead content of petrol and the growing use of unleaded fuel are expected to lead to reductions in the environmental lead burden, however, until unleaded fuel becomes universally accepted lead contamination, particularly of roadside soils and vegetation is a major cause for concern. A direct relationship between car exhaust, the Pb content of needles of Abies alba and reduced growth has been observed and can extend hundreds of metres from major highways. Lead tolerance has been observed in higher plants growing mine waste soils and to a lesser extent on lead-contaminated roadside soils. Automobiles which are responsible for line sources of pollution emissions in rural and suburban areas have a more far-reaching impact on roadside vegetation, already under considerable stress, in urban areas. Information on heavy metal effects on vegetation in urban environments however, are scarce. Modeling and multivariate analysis of a few of the factors involved have provided only limited data related to plant performance in these complex environments. Therefore in this study, the extent of heavy metal pollution by Pb, Zn, Cu and Cd in soils and in dandelion plants in the city of Thessaloniki has been examined. 20 refs., 2 figs., 3 tabs.

  14. Extremely High Phosphate Sorption Capacity in Cu-Pb-Zn Mine Tailings.

    PubMed

    Huang, Longbin; Li, Xiaofang; Nguyen, Tuan A H

    2015-01-01

    Elevated inorganic phosphate (Pi) concentrations in pore water of amended tailings under direct revegetation may cause toxicity in some native woody species but not native forbs or herb species, all of which are key constituents in target native plant communities for phytostabilizing base metal mine tailings. As a result, Pi sorption capacity has been quantified by a conventional batch procedure in three types of base metal mine tailings sampled from two copper (Cu)-lead (Pb)-zinc (Zn) mines, as the basis for Pi-fertiliser addition. It was found that the Pi-sorption capacity in the tailings and local soil was extremely high, far higher than highly weathered agricultural soils in literature, but similar to those of volcanic ash soils. The Langmuir P-sorption maximum was up to 7.72, 4.12, 4.02 and 3.62 mg P g-1 tailings, in the fresh tailings of mixed Cu-Pb-Zn streams (MIMTD7), the weathered tailings of mixed Cu-Pb-Zn streams (MIMTD5), EHM-TD (fresh Cu-stream, high magnetite content) and local soil (weathered shale and schist), respectively. Physicochemical factors highly correlated with the high Pi-sorption in the tailings were fine particle distribution, oxalate and dithionite-citrate-bicarbonate extractable Fe (FeO and Fed), oxalate-extractable Al and Mn, and the levels of soluble Cd and Zn, and total S and Fe. Large amounts of amorphous Fe oxides and oxyhydroxides may have been formed from the oxidation of pyritic materials and redox cycles of Fe-minerals (such as pyrite (FeS2), ankerite (Ca(Fe Mg)(CO3)2 and siderite (FeCO3), as indicated by the extractable FeO values. The likely formation of sparingly soluble Zn-phosphate in the Pb-Zn tailings containing high levels of Zn (from sphalerite ((Zn,Fe)S, ZnS, (Zn,Cd)S)) may substantially lower soluble Zn levels in the tailings through high rates of Pi-fertiliser addition. As a result, the possibility of P-toxicity in native plant species caused by the addition of soluble phosphate fertilizers would be minimal. PMID

  15. Variation of photon interaction parameters with energy for some Cu-Pb alloys

    SciTech Connect

    Singh, Tejbir Kaur, Sarpreet; Kaur, Parminder; Kaur, Harvinder; Singh, Parjit S.

    2015-08-28

    Various photon interaction parameters (mass attenuation coefficients, effective atomic numbers and effective electron numbers) have been computed for different compositions of Cu-Pb alloys in the wide energy regime of 1 keV to 100 GeV. The mass attenuation coefficients have been computed using mixture rule with the help of WinXCom (mass attenuation coefficient database for elements). The variation of mass attenuation coefficients, effective atomic numbers and electron density has been analysed and discussed in terms of dominance of different photon interaction processes viz. Compton scattering, photoelectric effect and pair production.

  16. Effect of Ni substitution for Cu in the vortex state of (Bi,Pb):2223 superconductor

    SciTech Connect

    Pop, A.V.

    1999-09-10

    The influence of the partial substitution of x = 0.02 Ni for Cu on the magnetoresistivity in the (Bi,Pb):2223 superconductor has been investigated. The resistive transitions were studied under magnetic fields up to 0.7 Tesla by using the dp/dT versus T curves. The Arrhenius plots shows that the dissipation processes are induced by two distinct regimes. In the high temperature regime the activation energy is proportional to lnB and to B{sup {minus}1} in low temperature regime. The main dissipation processes in these regimes are discussed.

  17. Extremely High Phosphate Sorption Capacity in Cu-Pb-Zn Mine Tailings

    PubMed Central

    Huang, Longbin; Li, Xiaofang; Nguyen, Tuan A. H.

    2015-01-01

    Elevated inorganic phosphate (Pi) concentrations in pore water of amended tailings under direct revegetation may cause toxicity in some native woody species but not native forbs or herb species, all of which are key constituents in target native plant communities for phytostabilizing base metal mine tailings. As a result, Pi sorption capacity has been quantified by a conventional batch procedure in three types of base metal mine tailings sampled from two copper (Cu)-lead (Pb)-zinc (Zn) mines, as the basis for Pi-fertiliser addition. It was found that the Pi-sorption capacity in the tailings and local soil was extremely high, far higher than highly weathered agricultural soils in literature, but similar to those of volcanic ash soils. The Langmuir P-sorption maximum was up to 7.72, 4.12, 4.02 and 3.62 mg P g-1 tailings, in the fresh tailings of mixed Cu-Pb-Zn streams (MIMTD7), the weathered tailings of mixed Cu-Pb-Zn streams (MIMTD5), EHM-TD (fresh Cu-stream, high magnetite content) and local soil (weathered shale and schist), respectively. Physicochemical factors highly correlated with the high Pi-sorption in the tailings were fine particle distribution, oxalate and dithionite-citrate-bicarbonate extractable Fe (FeO and Fed), oxalate-extractable Al and Mn, and the levels of soluble Cd and Zn, and total S and Fe. Large amounts of amorphous Fe oxides and oxyhydroxides may have been formed from the oxidation of pyritic materials and redox cycles of Fe-minerals (such as pyrite (FeS2), ankerite (Ca(Fe Mg)(CO3)2 and siderite (FeCO3), as indicated by the extractable FeO values. The likely formation of sparingly soluble Zn-phosphate in the Pb-Zn tailings containing high levels of Zn (from sphalerite ((Zn,Fe)S, ZnS, (Zn,Cd)S)) may substantially lower soluble Zn levels in the tailings through high rates of Pi-fertiliser addition. As a result, the possibility of P-toxicity in native plant species caused by the addition of soluble phosphate fertilizers would be minimal. PMID

  18. Variation of photon interaction parameters with energy for some Cu-Pb alloys

    NASA Astrophysics Data System (ADS)

    Singh, Tejbir; Kaur, Sarpreet; Kaur, Parminder; Kaur, Harvinder; Singh, Parjit S.

    2015-08-01

    Various photon interaction parameters (mass attenuation coefficients, effective atomic numbers and effective electron numbers) have been computed for different compositions of Cu-Pb alloys in the wide energy regime of 1 keV to 100 GeV. The mass attenuation coefficients have been computed using mixture rule with the help of WinXCom (mass attenuation coefficient database for elements). The variation of mass attenuation coefficients, effective atomic numbers and electron density has been analysed and discussed in terms of dominance of different photon interaction processes viz. Compton scattering, photoelectric effect and pair production.

  19. Interaction of Cu(2+), Pb (2+), Zn (2+) with trypsin: what is the key factor of their toxicity?

    PubMed

    Zhang, Tong; Zhang, Hao; Liu, Guiliang; Gao, Canzhu; Liu, Rutao

    2014-11-01

    Heavy metals possess great endangerment to environment even human health because of their indissolubility and bioaccumulation. The toxicity of heavy metal ions (Cu(2+), Pb(2+), Zn(2+)) to trypsin was investigated by fluorescence, synchronous fluorescence, UV-vis absorption, circular dichroism (CD) spectroscopy, isothermal titration calorimetry (ITC), and enzyme activity assay. The experimental results showed that toxic effect of heavy metal ions was due to their own characteristic, rather than the electric charges of the ion. Zn(2+) could not show the obvious toxicity to trypsin, while the structure and function of trypsin was damaged when the enzyme explored to Cu(2+) and Pb(2+). From the spectra results, we found that Cu(2+) would bind with trypsin, which lead to the fluorescence quenched and hydrophobicity increased. Pb(2+) could also change the structure and reduce the activity of trypsin in high concentration. In vitro measurement, the toxicity order of heavy metal ions to trypsin is: Cu(2+) > Pb(2+) > Zn(2+). In addition, isothermal titration calorimetry analysis proved that the interactions between Cu(2+), Pb(2+), Zn(2+) and trypsin were all spontaneous and exothermic, which indicated the adverse effect of these heavy metal ions to trypsin. PMID:25323557

  20. Distribution, bioavailability, and potential ecological risk of Cu, Pb, and Zn in soil in a potential groundwater source area.

    PubMed

    Teng, Yanguo; Feng, Dan; Wu, Jin; Zuo, Rui; Song, Liuting; Wang, Jinsheng

    2015-05-01

    In this study, we examined three horizontal and vertical soil profiles along a sewage drainage ditch in order to determine the spatial distribution of Cu, Pb, and Zn in soils and to assess the bioavailability and potential ecological risks associated with these metals in a potential groundwater source area. Results showed that the concentrations of Cu, Pb, and Zn were approximately at background level, suggesting that human activities (industrial and agricultural pollution) had a negligible influence on these metals in soil, and that the concentrations reflected the natural background levels in the study area. Cu, Pb, and Zn concentrations were slightly higher in topsoil (0-20 cm) than deeper in the soil profile. Using a modified BCR sequential extraction method to evaluate the mobility and bioavailability of metals showed that the potential bioavailability sequence of Cu, Pb, and Zn at three depths in the soil profile was in the order Cu ≈ Pb < Zn. The potential ecological risk from the metals was evaluated using risk assessment code, and the results suggest that Cu and Zn pose no or low risk, while there is a low or medium risk from Pb. Results from groundwater monitoring showed that the groundwater was not polluted by leaching from soil. PMID:25910722

  1. Electrokinetic enhancement on phytoremediation in Zn, Pb, Cu and Cd contaminated soil using potato plants.

    PubMed

    Aboughalma, Hanssan; Bi, Ran; Schlaak, Michael

    2008-07-01

    The use of a combination of electrokinetic remediation and phytoremediation to decontaminate soil polluted with heavy metals has been demonstrated in a laboratory-scale experiment. Potato tubers were planted in plastic vessels filled with Zn, Pb, Cu and Cd contaminated soil and grown in a greenhouse. Three of these vessels were treated with direct current electric field (DC), three with alternative current (AC) and three remained untreated as control vessels. The soil pH varied from anode to cathode with a minimum of pH 3 near the anode and a maximum of pH 8 near the cathode in the DC treated soil profile. There was an accumulation of Zn, Cu and Cd at about 12 cm distance from anode when soil pH was 5 in the DC treated soil profile. There was no significant metal redistribution and pH variation between anode and cathode in the AC soil profile. The biomass production of the plants was 72% higher under AC treatment and 27% lower under DC treatment compared to the control. Metal accumulation was generally higher in the plant roots treated with electrical fields than the control. The overall metal uptake in plant shoots was lower under DC treatment compared to AC treatment and control, although there was a higher accumulation of Zn and Cu in the plant roots treated with electrical fields. The Zn uptake in plant shoots under AC treatment was higher compared to the control and DC treatment. Zn and Cu accumulation in the plant roots under AC and DC treatment was similar, and both were higher comparing to control. Cd content in plant roots under all three treatments was found to be higher than that in the soil. The Pb accumulation in the roots and the uptake into the shoots was lower compared to its content in the soil. PMID:18569305

  2. Uptake and toxicity of Cd, Cu and Pb mixtures in the isopod Asellus aquaticus from waterborne exposure.

    PubMed

    Van Ginneken, M; De Jonge, M; Bervoets, L; Blust, R

    2015-12-15

    The present study evaluated interactions of waterborne Cd, Cu and Pb mixtures on metal uptake rates in the isopod Asellus aquaticus and related this to mixture effects on toxicity. Secondly, it was assessed whether observed mixture effects were better related to isopod body concentrations compared to exposure concentrations. Isopods were exposed for 10 days to single, binary and tertiary mixtures including five different concentrations of Cd (0.107 to 277 μg L(-1)), Cu (3.35 to 2117 μg L(-1)) and Pb (0.782 to 443 μg L(-1)). Mortality was assessed every day while isopod body concentrations, growth (biomass) and energy reserves (glycogen, lipid and protein reserves) were assessed at the end of the experiment. Synergistic interactions of combined Cd and Pb exposure on Cd and Pb uptake as well as on growth rates and mortality rates were observed. Mixture effects of combined Cd and Pb exposure on toxicity endpoints were directly related to increased Cd uptake in the Cd+Pb treatment. No mixture interactions of Cu on Cd or Pb uptake (and vice versa), nor on toxicity endpoints were observed. All toxicity endpoints were related to body concentrations. However, mixture effects disappeared when growth and mortality rates were expressed on body concentrations instead of exposure concentrations. By combining information of mixture effects on metal uptake with mixture toxicity data, the present study provides more insight in the way metal mixtures interfere with aquatic organisms and how they can induce toxic effects. PMID:26282750

  3. A two-dimensional phase separation on the spherical surface of the metallic glass Au55Pb22.5Sb22.5

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Johnson, W. L.

    1982-01-01

    Recent experiments indicate that a phase separation in a spherical sample of the metallic glass Au55Pb22.5Sb22.5 occurs near the surface of the sphere. This strongly suggests either a contribution of surface-free energy to the decomposition process or a possible influence of near surface impurities absorbed during synthesis of the sphere. The surface phase separation has been studied as a function of cooling rate of the sphere. At high cooling rates (small sphere sizes), the surface separation disappears altogether suggesting that the surface of the parent liquid droplet is initially homogeneous.

  4. Reactions of [Cu(X)(BPEP-Ph)] (X = PF6, SbF6) with silyl compounds. Cooperative bond activation involving non-coordinating anions.

    PubMed

    Nakajima, Yumiko; Tsuchimoto, Takahiro; Chang, Yung-Hung; Takeuchi, Katsuhiko; Ozawa, Fumiyuki

    2016-02-01

    Bond activation of silyl compounds, assisted by the cooperative action of non-coordinating anions, is achieved using Cu(I) complexes coordinated with a PNP-pincer type phosphaalkene ligand, [Cu(X)(BPEP-Ph)] (X = PF6 (1a), SbF6 (1b); BPEP-Ph = 2,6-bis[1-phenyl-2-(2,4,6-tri-tert-butylphenyl)-2-phosphaethenyl]pyridine). Complexes 1a and 1b react with Me3SiCN to form Me3SiF and Cu(i) cyanide complexes of the formula [Cu(CN-EF5)(BPEP-Ph)] (E = P (2a), Sb (2b)), in which the CN ligand is associated with the EF5 group arising from EF6(-). Formation of the intermediary isonitrile complex [Cu(CNSiMe3)(BPEP-Ph)](+)SbF6(-) (3b) is confirmed by its isolation. Thus, a two-step reaction process involving coordination of Me3SiCN, followed by nucleophilic attack of SbF6(-) on the silicon atom of 3b is established for the conversion of 1b to 2b. Complex 1b cleaves the H-Si bond of PhMe2SiH as well. The isolation and structural identification of [Cu(BPEP-Ph)](+)BAr(F)4(-) (1c) (BAr(F)4 = B{3,5-(CF3)2C6H3}4) as a rare example of a T-shaped, three-coordinated Cu(i) complex is reported. PMID:26455594

  5. Fabrication of a high-performance Pb-PtCu/CNT catalyst for methanol electro-oxidation

    NASA Astrophysics Data System (ADS)

    Huang, Yiyin; Cai, Jindi; Zheng, Shiying; Guo, Yonglang

    2012-07-01

    This work presents a general strategy to fabricate a new type of hierarchically structured trimetallic nano-catalyst. Cu nanoparticles are partially displaced by Pt4+ and then further decorated by Pb (II) species on the carbon nanotube surface. The X-ray photoelectron spectroscopy and cyclic voltammograms data demonstrate that Cu is inside the particles while Pb (II) species are outside. The novel Pb-PtCu/CNT catalyst exhibits superior stability and CO poisoning tolerance during potential cycling. Methanol oxidation peak current of this novel catalyst (94.4 mA cm-2) is almost two times higher than that of the commercial PtRu/C (50 mA cm-2).

  6. Applications of GIS and a Handheld XRF for Mapping Cu and Pb Contaminations in Abandoned Mine Areas

    NASA Astrophysics Data System (ADS)

    Lee, H.; Choi, Y.; Yi, H.; Kim, D. H.

    2014-12-01

    In this study, we used a handheld X-Ray Fluorescence (XRF) and Geographic Information Systems (GIS) to create soil contamination maps regarding Cu and Pb around abandoned mining areas. The Busan abandoned mine in Korea was selected as a study area. Digital Elevation Models (DEMs)-based Terrain analysis was performed to identify locations for investigating the soil contamination. At the locations, Cu and Pb contaminations were investigated by using the handheld XRF. The field investigation data were inputted into GIS and utilized to create soil contamination maps using the ordinary kriging method (one of the geostatistical interpolation techniques used in GIS). High concentrations of Cu and Pb were shown at the waste and tailings dumps around abandoned mine openings. As a result, we could know that the method for creating soil contamination maps using a handheld and GIS can be utilized effectively.

  7. Heavy metal (Cu, Zn, Cd and Pb) contamination of vegetables in urban India: a case study in Varanasi.

    PubMed

    Sharma, Rajesh Kumar; Agrawal, Madhoolika; Marshall, Fiona M

    2008-07-01

    The contributions of heavy metals in selected vegetables through atmospheric deposition were quantified in an urban area of India. Deposition rate of Zn was recorded maximum followed by Cu, Cd and Pb. The concentrations of Zn and Cu were highest in Brassica oleracea, Cd in Abelmoschus esculentus and B. oleracea, while Pb was highest in Beta vulgaris. Heavy metal pollution index showed that B. oleracea was maximally contaminated with heavy metals followed by A. esculentus and then B. vulgaris. The results of washing showed that atmospheric deposition has contributed to the increased levels of heavy metals in vegetables. Both Cu and Cd posed health risk to local population via test vegetables consumption, whereas Pb posed the same only through B. oleracea. The study concludes that atmospheric depositions can elevate the levels of heavy metals in vegetables during marketing having potential health hazards to consumers. PMID:18031880

  8. Nature of electron correlation and hybridization in NixCu1-xMnSb Heusler alloys

    NASA Astrophysics Data System (ADS)

    Sarkar, I.; Yusuf, S. M.; Halder, M.; Gloskovskii, A.; Drube, W.

    2016-08-01

    The electronic structure of Heusler alloys having mixed magnetic phases, comprising of vicinal anti-ferromagnetic and ferromagnetic orders, is of great significance. We present the results of an electronic structure study on NixCu1-xMnSb Heusler alloys, using Mn-2p core-level photoemission spectroscopy. Room temperature data in the paramagnetic phase reveal a non-monotonic variation of both electron correlation strength and conduction-band hybridization such that the former enhances while the latter weakens for compositions showing a mixed phase relative to compositions at the phase boundaries to the ordered phases. The results suggest a possible electronic driving force for settling mixed-magnetic phases.

  9. Primary Phase Field of the Pb-Doped 2223 High-Tc Superconductor in the (Bi, Pb)-Sr-Ca-Cu-O System

    PubMed Central

    Wong-Ng, W.; Cook, L. P.; Kearsley, A.; Greenwood, W.

    1999-01-01

    Both liquidus and subsolidus phase equilibrium data are of central importance for applications of high temperature superconductors in the (Bi, Pb)-Sr-Ca-Cu-O system, including material synthesis, melt processing and single crystal growth. The subsolidus equilibria of the 110 K high-Tc Pb-doped 2223 ([Bi, Pb], Sr, Ca, Cu) phase and the location of the primary phase field (crystallization field) have been determined in this study. For the quantitative determination of liquidus data, a wicking technique was developed to capture the melt for quantitative microchemical analysis. A total of 29 five-phase volumes that include the 2223 phase as a component was obtained. The initial melt compositions of these volumes range from a mole fraction of 7.3 % to 28.0 % for Bi, 11.3 % to 27.8 % for Sr, 1.2 % to 19.4 % for Pb, 9.8 % to 30.8 % for Ca, and 17.1 % to 47.0 % for Cu. Based on these data, the crystallization field for the 2223 phase was constructed using the convex hull technique. A section of this “volume” was obtained by holding two components of the composition at the median value, allowing projection on the other three axes to show the extent of the field.

  10. Stabilization of Pb and Cu in contaminated soils using (nano)oxides - a preliminary study

    NASA Astrophysics Data System (ADS)

    Komárek, Michael; Michálková, Zuzana; Vaněk, Aleš

    2013-04-01

    Chemical stabilization techniques (the application of various stabilizing amendments, which by chemical means reduces contaminant mobility, bioavailability and bioaccessibility) have shown to be possible less destructive alternatives to conventional remediation options. Most stabilization techniques aim at rendering less available the metal(loid) fractions that can pose significant environmental and/or toxicological risks and protecting the functionality of the soil environment. Nano-particulate oxides (particle size of 1-100 nm) are important scavengers of contaminants in soils and due to their reactive and relatively large specific surface area, engineered oxide nanoparticles are promising materials for the remediation of soils contaminated with inorganic pollutants. However, studies assessing the efficiency of these amendments in contaminated soils are still rather scarce. Therefore, the aim of this work is to evaluate the stabilization efficiency of four (nano)oxides (maghemite, magnetite, gibbsite and amorphous Mn oxide (AMO)) in two soils contaminated with Cu (400 mg/kg; pH 3.6) and Pb (1500 mg/kg; pH 5.5), respectively, using chemical extraction methods (CaCl2, EDTA and the BCR sequential extraction) and direct sampling of soil solution using rhizons. The results suggest that the application of the oxides did not influence the pH of the soils, with the only exception of the AMO, which increased the pH and resulted into the formation of MnCO3 on the oxide surface (data from SEM and XRD). Additionally, the high reactivity of the oxides led to increased DOC concentrations originating from the dissolved soil organic matter, especially in the case of the AMO. The AMO was also the most efficient stabilizing amendment for Cu (most significant decrease in Cu in soil solution, in the exchangeable fraction and CaCl2/EDTA extracts), promoted by the pH increase. Despite their lower particle size, maghemite, magnetite and gibbsite were less efficient; although partial

  11. Trace metals (Co, Ni, Cu, Cd, and Pb) in the southern East/Japan Sea

    NASA Astrophysics Data System (ADS)

    Kang, Jeongwon; Choi, Man-Sik; Jeong, Kap-Sik; Lee, Chang-Bok

    2014-03-01

    Total dissolvable metals (Co, Ni, Cu, Cd, and Pb) in both surface waters and the water columns were acquired in the southern East/Japan Sea during a cruise around the Ulleung Basin in June 2001 to understand the spatial distributions of the metals. Concentrations in offshore surface waters were found to be Co 60 ± 12 pM, Ni 2.16 ± 0.25 nM, Cu 1.85 ± 0.55 nM, Cd 0.134 ± 0.018 nM, and Pb 155 ± 40 pM. Spatial distributions in surface waters showed that metal levels were generally enhanced at coastal sites in both Korea and Japan, where the metal distributions indicated complex patterns due to inputs, biogeochemical processes, and physical factors including upwelling. The Co distributions in the water columns seemed to be influenced predominantly by surface and bottom inputs, scavenged rather than regenerated at depth. For Cd, there was generally good agreement between the Cd and PO4 depth distributions, in agreement with the literature. The Cd/PO4 ratio from the water columns was found to be 0.133-0.203, lower than that in other marginal seas (e.g. the East/South China Seas and the Philippine Sea) of the western Pacific Ocean; this might be a result of the fast ventilation rate in this sea. The vertical Pb profile showed typical scavenged-type behavior with a surface maximum and deep minimum. From a comparison of inputs from the atmosphere and the Tsushima Warm Current, atmospheric deposition is substantial enough that it cannot be ignored, and its role in metal cycling is more significant in the offshore zone.

  12. High-T(c) superconducting films of Bi-Pb-Sr-Ca-Cu oxide prepared by plasma spraying

    NASA Astrophysics Data System (ADS)

    Yoshida, Yuji; Kitahara, Shigeru; Togano, Kazumasa; Yuyama, Michinari; Inoue, Kiyoshi

    1989-04-01

    Superconducting properties and microstructures of the Bi-Pb-Sr-Ca-Cu oxide films prepared by plasma spraying have been studied. Films with a thickness of about 150 microns have been prepared from Bi(1.52)Pb(0.48)Sr(1.66)Ca(1.18)Cu(2.31)O(x) powders. The as-sprayed films, deposited on nickel substrate, are amorphous and not superconductive. After annealing in air at 840 C the films exhibit a zero-resistance temperature of 107 K (zero field) with a transition width of about 11 K.

  13. Cu-Zn-Pb multi isotopic characterization of a small watershed (Loire river basin, France)

    NASA Astrophysics Data System (ADS)

    Desaulty, A. M.; Millot, R.; Perret, S.; Bourrain, X.

    2015-12-01

    Combating metal pollution in surface water is a major environmental, public health and economic issue. Knowledge of the behavior of metals, such as copper (Cu), zinc (Zn) and lead (Pb) in sediments and dissolved load, is a key factor to improve the management of rivers. Recent advances in mass spectrometry related to the development of MC-ICPMS allow to analyze the isotopic composition of these elements, and previous studies show the effectiveness of isotopic analyses to determine the anthropogenic sources of pollution in environment. The goal of this study is to use the Cu-Zn-Pb multi-isotopic signature to track the pollutions in surface water, and to understand the complex processes causing the metals mobilization and transport in environment. More particularly we investigate the mechanisms of distribution between the dissolved load and particulate load, known to play an important role in the transport of metals through river systems. As case study, we chose a small watershed, poorly urbanized in the Loire river basin. Its spring is in a pristine area, while it is only impacted some kilometers further by the releases rich in metals coming from a hospital water treatment plant. First a sampling of these liquid effluents as well as dissolved load and sediment from upstream to downstream was realized and their concentrations and isotopic data were determined. Then to simulate a lot of potential natural and anthropogenic modifications of environmental conditions, we made sequential extraction protocol using various reagents on the sediments. Isotopic analyzes were performed also on the various extracting solutions. Isotopic ratios were measured using a Neptune MC-ICPMS at the BRGM, after a protocol of purification for Zn and Cu. The results showed that, these isotopic systematics reveal important informations about the mechanists of mobilization and transport of metals through river systems. However experiments performed under laboratory conditions will be necessary

  14. Experimental determination of nonequilibrium transport parameters reflecting the competitive sorption between Cu and Pb in slag-sand column.

    PubMed

    Chung, Jaeshik; Kim, Young-Jin; Lee, Gwanghun; Nam, Kyoungphile

    2016-07-01

    Competitive sorption and resulting nonequilibrium transport of Cu and Pb were investigated using slag as a primary sorbent. A series of estimation models were applied based on the equilibrium, and nonequilibrium sorption respectively, and finally calibrated by incorporating the experimentally determined batch kinetic data. When applied individually, the behavior of metals in slag-sand column were well predicted by both equilibrium and nonequilibrium models in CXTFIT code. However, coexisting Cu and Pb exhibited competition for sorption sites, generating an irregular breakthrough curves such as overshoot (higher concentration in effluent than the feed concentration) of Cu and corresponding earlier peak of Pb followed by gradual re-rising. Although two-site nonequilibrium model further considers coupled hydrochemical process, desorption of the Cu from competition made the model prediction inaccurate. However, the parameter estimation could be improved by incorporating the experimentally determined mass transfer rate, ωexp from batch kinetics. Based on the calibrated model, the fraction of instantaneous retardation, βexp of Pb decreased from 0.41 in the single system to 0.30 in the binary system, indicating the shift from equilibrium to nonequilibrium state, where which of Cu increased from 0.39 to 0.94, representing the shift towards equilibrium. The modified results were also compared with five-step sequential extraction data, confirming that the shift of particular metal fractions from the competition triggered the nonequilibrium transport. PMID:27060642

  15. Electronic and Thermoelectric Properties of Layered Sn- and Pb-Doped Ge2Sb2Te5 Alloys Using First Principle Calculations

    NASA Astrophysics Data System (ADS)

    Singh, Janpreet; Singh, Gurinder; Kaura, Aman; Tripathi, S. K.

    2016-06-01

    A computational study on stable hexagonal phase of undoped, and Sn- and Pb-doped Ge2Sb2Te5 (GST) phase change materials has been carried out. The electronic structure, lattice dynamics and thermoelectric properties of doped GST have been extensively investigated using ab initio methods with virtual crystal approximation. The hexagonal symmetry of the GST is maintained with the addition of Sn and Pb dopants. The lattice parameters and atomic volume of the Sn-doped GST structure is larger than that of the undoped GST. Electronic band structure calculations show that there is an increase in band gap with the increase in the concentration of Sn (≤4.4 at.%). However, with the addition of a very small amount of Pb, there is a continuous decrease in lattice parameters and band gap values. The calculated energy band structure is then used in combination with the Boltzmann transport equation to calculate the thermoelectric parameters of GST and Sn- and Pb-doped materials. Seebeck coefficient ( S), electronic thermal conductivity ( κ e) and the thermoelectric figure-of-merit ( ZT) have been calculated with the help of BoltzTraP code. It was found that the thermoelectric properties of GST are enhanced with the addition of Sn.

  16. Environmental and health risk assessment of Pb, Zn, As and Sb in soccer field soils and sediments from mine tailings: solid speciation and bioaccessibility.

    PubMed

    Pascaud, Grégoire; Leveque, Thibaut; Soubrand, Marilyne; Boussen, Salma; Joussein, Emmanuel; Dumat, Camille

    2014-03-01

    Areas polluted by the persistent presence of metal(loid)s induce health problems, especially when recreational activities (on land or water) promote human exposure to the pollutants. This study focuses on one of the most encountered worldwide mining waste, i.e. those from the extraction of Pb-Zn-Ag. The representative Pb-Zn-rich tailing (about 64,100 m(3)) sampled is located near a soccer field and a famous river for fishing. The scientific interests is relative to: (1) mobility and bioaccessibility of metal(oid)s, (2) human risk assessments and (3) relationship between human risks and solid-bearing phases in the environment. Soccer field soils, tailings and sediments from the nearby river were sampled; moreover, metal(loid) speciation (from BCR experiments) and bioaccessibility were measured and solid speciation performed by X-ray diffraction and electron microscopy in order to highlight metal(loid) dispersion and impact. Results demonstrate that the soccer field is highly contaminated by Pb, Zn, As and Sb due primarily to waste runoff. In terms of risk assessment, Pb and As human bioaccessibility highlights the major health risk (48 and 22.5 % of human bioaccessibility, respectively). Since local populations are regularly in close contact with metal(loid)s, the health risk due to pollutant exposure needs to be reduced through sustainable waste disposal and the rehabilitation of polluted sites. PMID:24306721

  17. Antiferromagnetism in EuCu2As2 and EuCu1.82Sb2 single crystals

    SciTech Connect

    Anand, V. K.; Johnston, D. C.

    2015-05-07

    Single crystals of EuCu2As2 and EuCu2Sb2 were grown from CuAs and CuSb self-flux, respectively. The crystallographic, magnetic, thermal, and electronic transport properties of the single crystals were investigated by room-temperature x-ray diffraction (XRD), magnetic susceptibility χ versus temperature T, isothermal magnetization M versus magnetic field H, specific heat Cp(T), and electrical resistivity ρ(T) measurements. EuCu2As2 crystallizes in the body-centered tetragonal ThCr2Si2-type structure (space group I4/mmm), whereas EuCu2Sb2 crystallizes in the related primitive tetragonal CaBe2Ge2-type structure (space group P4/nmm). The energy-dispersive x-ray spectroscopy and XRD data for the EuCu2Sb2 crystals showed the presence of vacancies on the Cu sites, yielding the actual composition EuCu1.82Sb2. The ρ(T) and Cp(T) data reveal metallic character for both EuCu2As2 and EuCu1.82Sb2. Antiferromagnetic (AFM) ordering is indicated from the χ(T),Cp(T), and ρ(T) data for both EuCu2As2 (TN = 17.5 K) and EuCu1.82Sb2 (TN = 5.1 K). In EuCu1.82Sb2, the ordered-state χ(T) and M(H) data suggest either a collinear A-type AFM ordering of Eu+2 spins S = 7/2 or a planar noncollinear AFM structure, with the ordered moments oriented in the tetragonal ab plane in either case. This ordered-moment orientation for the A-type AFM is consistent with calculations with magnetic dipole interactions. As a result, the anisotropic χ(T) and isothermal M(H) data for EuCu2As2, also containing Eu+2 spins S = 7/2, strongly deviate from the predictions of molecular field theory for collinear AFM ordering and the

  18. Pb, Cu, and Zn distributions at humic acid-coated metal-oxide surfaces

    NASA Astrophysics Data System (ADS)

    Wang, Yingge; Michel, F. Marc; Choi, Yongseong; Eng, Peter J.; Levard, Clement; Siebner, Hagar; Gu, Baohua; Bargar, John R.; Brown, Gordon E.

    2016-09-01

    Mineral surfaces are often coated by natural organic matter (NOM), which has a major influence on metal-ion sorption and sequestration because of the abundance of binding sites in such coatings and the changes they cause in local nanoscale environments. The effects of NOM coatings on mineral surfaces are, however, still poorly understood at the molecular level due to the complexity of these systems. In this study, we have applied long-period X-ray standing wave-fluorescence yield (LP-XSW-FY) spectroscopy to measure the partitioning of naturally present Cu(II) (0.0226%), Zn(II) (0.009%), and Pb(II) (∼0.0004%) between Elliott Soil Humic Acid (ESHA) coatings and three model single-crystal metal-oxide substrates: α-Al2O3 (0 0 0 1), α-Al2O3 (1 -1 0 2), and α-Fe2O3 (0 0 0 1). The competitive sorption effects among these metal ions for binding sites in the ESHA coatings and on the metal-oxide surfaces were investigated as a function of reaction time, calcium content, and solution pH. Pb(II) ions present in the ESHA coatings were found to redistribute to reactive α-Al2O3 (1 -1 0 2) and α-Fe2O3 (0 0 0 1) surfaces after 3 h of reaction (pH = 6.0, [Ca(II)] = 2 mM). Pb(II) partitioning onto these reactive metal-oxide surfaces increased with increasing reaction time (up to 7 d). In addition, the partitioning of Cu(II) and Zn(II) from the ESHA coating to the α-Fe2O3 (0 0 0 1) substrate increased slightly with reaction time (2.4% and 3.7% for Cu(II) and Zn(II), respectively, after 3 h and 6.4% and 7.7% for Cu(II) and Zn(II), respectively, after 72 h of reaction time). However, no changes in the partitioning of Cu(II) and Zn(II) onto the α-Al2O3 (1 -1 0 2) surface were observed with increasing reaction time, suggesting that these ions strongly complex with functional groups in the ESHA coatings. Similar results were obtained for Cu(II) and Zn(II) on the ESHA-coated α-Al2O3 (1 -1 0 2) surfaces in samples without the addition of calcium. However, the amounts of Pb

  19. Immobilization of Pb and Cu in polluted soil by superphosphate, multi-walled carbon nanotube, rice straw and its derived biochar.

    PubMed

    Rizwan, Muhammad Shahid; Imtiaz, Muhammad; Huang, Guoyong; Chhajro, Muhammad Afzal; Liu, Yonghong; Fu, Qingling; Zhu, Jun; Ashraf, Muhammad; Zafar, Mohsin; Bashir, Saqib; Hu, Hongqing

    2016-08-01

    Lead (Pb) and copper (Cu) contamination in croplands pose severe health hazards and environmental concerns throughout soil-food chain transfer. In the present study, BCR, TCLP, CaCl2, and SBET techniques were employed to evaluate the simultaneous effectiveness of rice straw (RS) and its derived biochar (BC), multiwall carbon nanotube (MWCNT), and single superphosphate (SSP) to immobilize the Pb and Cu in co-contaminated soil. The BCR sequential extraction results suggested that with increasing BC and SSP amount, the acid-soluble fractions decreased while oxidizable and residual proportions of Pb and Cu were increased significantly. Compared to SSP, the application of BC amendment substantially modified partitioning of Cu from easily exchangeable phase to less bioavailable residual bound fraction. The immobilized Pb and Cu were mainly transformed to reducible forms. The TCLP and CaCl2-extracted Pb and Cu were reduced significantly by the addition of BC compared to RS and MWCNT, whereas the bio-accessibility of Pb significantly reduced with RS addition. SSP showed better results for Pb immobilization while marginal for Cu in co-contaminated soil. Overall, the addition of BC offered the best results and could be effective in both Pb and Cu immobilization thereby reducing their mobility and bioavailability in the co-contaminated soil. PMID:27121017

  20. Effect of the addition of industrial by-products on Cu, Zn, Pb and As leachability in a mine sediment.

    PubMed

    Rodríguez-Jordá, M Paz; Garrido, Fernando; García-González, M Teresa

    2012-04-30

    A series of incubation and leaching experiments were performed to assess the feasibility of three industrial by-products (red gypsum (RG), sugar foam (SF) and ashes from the combustion of biomass (ACB)) to reduce the leachability of Cu, Pb, Zn and As in a sediment of São Domingos mine (Portugal). The changes in the element solid phase speciation were also evaluated by applying a sequential extraction procedure. All amendments significantly reduced the leachability of Zn and Cu, whereas the treatment with RG+SF+ACB also decreased the mobility of As. The reduction in Cu leachability was especially remarkable. This could be due to the great affinity of carbonates (included in SF and SF+ACB amendments) to precipitate with Cu, and maghemite and rutile (RG amendment) for acting as relevant sorbents for Cu. Pb was the least mobile element in the sediment and none of the treatments reduced its mobility. The sequential extraction reveals that the amendments induced a significant decrease in the concentration of elements associated with the residual fraction. Cu, Pb and As are redistributed from the residual fraction to the Al, Fe, and Mn hydr(oxides) fraction and Zn from the residual fraction to the water/acid soluble, exchangeable and bound to carbonates pool. PMID:22341746

  1. Defect properties of Sb- and Bi-doped CuInSe{sub 2}: The effect of the deep lone-pair s states

    SciTech Connect

    Park, Ji-Sang; Yang, Ji-Hui; Ramanathan, Kannan; Wei, Su-Huai

    2014-12-15

    Bi or Sb doping has been used to make better material properties of polycrystalline Cu{sub 2}(In,Ga)Se{sub 2} as solar cell absorbers, including the experimentally observed improved electrical properties. However, the mechanism is still not clear. Using first-principles method, we investigate the stability and electronic structure of Bi- and Sb-related defects in CuInSe{sub 2} and study their effects on the doping efficiency. Contrary to previous thinking that Bi or Sb substituted on the anion site, we find that under anion-rich conditions, the impurities can substitute on cation sites and are isovalent to In because of the formation of the impurity lone pair s states. When the impurities substitute for Cu, the defects act as shallow double donors and help remove the deep In{sub Cu} level, thus resulting in the improved carrier life time. On the other hand, under anion-poor conditions, impurities at the Se site create amphoteric deep levels that are detrimental to the device performance.

  2. Defect properties of Sb- and Bi-doped CuInSe2: The effect of the deep lone-pair s states

    NASA Astrophysics Data System (ADS)

    Park, Ji-Sang; Yang, Ji-Hui; Ramanathan, Kannan; Wei, Su-Huai

    2014-12-01

    Bi or Sb doping has been used to make better material properties of polycrystalline Cu2(In,Ga)Se2 as solar cell absorbers, including the experimentally observed improved electrical properties. However, the mechanism is still not clear. Using first-principles method, we investigate the stability and electronic structure of Bi- and Sb-related defects in CuInSe2 and study their effects on the doping efficiency. Contrary to previous thinking that Bi or Sb substituted on the anion site, we find that under anion-rich conditions, the impurities can substitute on cation sites and are isovalent to In because of the formation of the impurity lone pair s states. When the impurities substitute for Cu, the defects act as shallow double donors and help remove the deep InCu level, thus resulting in the improved carrier life time. On the other hand, under anion-poor conditions, impurities at the Se site create amphoteric deep levels that are detrimental to the device performance.

  3. Isotopic Ag-Cu-Pb record of silver circulation through 16th-18th century Spain.

    PubMed

    Desaulty, Anne-Marie; Telouk, Philippe; Albalat, Emmanuelle; Albarède, Francis

    2011-05-31

    Estimating global fluxes of precious metals is key to understanding early monetary systems. This work adds silver (Ag) to the metals (Pb and Cu) used so far to trace the provenance of coinage through variations in isotopic abundances. Silver, copper, and lead isotopes were measured in 91 coins from the East Mediterranean Antiquity and Roman world, medieval western Europe, 16th-18th century Spain, Mexico, and the Andes and show a great potential for provenance studies. Pre-1492 European silver can be distinguished from Mexican and Andean metal. European silver dominated Spanish coinage until Philip III, but had, 80 y later after the reign of Philip V, been flushed from the monetary mass and replaced by Mexican silver. PMID:21606351

  4. Axial anisotropy of intergrain critical current in Bi-Pb-Sr-Ca-Cu-O

    NASA Astrophysics Data System (ADS)

    Umemura, Toshio; Egawa, Kunihiko; Wakata, Mitsunobu; Yoshizaki, Kiyoshi; Ni, Baorong; Matsushita, Teruo

    1990-08-01

    The intergrain critical current densities, J c, parallel and perpendicular to c-axis were measured as a function of the magnetic field at 4.2 and 77.3K by an ac inductive method for the fairly oriented Bi 1.6Pb 0.4Sr 2Ca 2Cu 3O y specimens. The J c's perpendicular to c-axis were higher than those parallel c-axis, about ten times within 5T at 4.2K, and about three times within 0.1T at 77.3K. Our results suggect the orientation of each grain to be especially worthwhile for performing the high J c at the low temperature.

  5. Fabrication and characterization of (Bi,Pb)-Sr-Ca-Cu-O (2223) bars

    SciTech Connect

    Chudzik, M.P.; Polzin, B.J.; Thayer, R.; Picciolo, J.J.; Fisher, B.L.; Lanagan, M.T.

    1996-08-01

    Bulk bars for current lead applications were fabricated from (Bi,Pb)- Sr-Ca-Cu-O (Bi-2223) for low thermal conductivity and high critical current. Bars measuring 17.8 cm in length were made by uniaxially pressing Bi-2223 powder of controlled (1.7/0.34)223 and (1.8/0.4)223 phase composition. The bulk bars were densified by subjecting them to a schedule of alternate liquid-phase sintering and cold isostatic pressing. Liquid phase sintering temperatures were optimized from differential thermal analysis and microstructure morphology. Phase purity and microstructure were evaluated by x-ray diffraction and scanning electron microscopy. Low-resistance silver contacts were applied to the bars by hot-pressing at 820{degrees}C and 3 MPa. Critical current densities {approx} 1000 A/cm{sup 3} (critical currents of 750 A at 77 K in self-field conditions) were achieved.

  6. Growth of nucleation sites on Pb-doped Bi2Sr2Ca1Cu2O8 + delta

    NASA Astrophysics Data System (ADS)

    Finnemore, D. K.; Xu, Ming; Kouzoudis, D.; Bloomer, T.; Kramer, M. J.; McKernan, Stuart; Balachandran, U.; Haldar, Pradeep

    1996-01-01

    In the growth of Bi2Sr2Ca2Cu3O10+δ from mixed powders of Pb-doped Bi2Sr2Ca1Cu2O8+δ and other oxides, it has been discovered that a dense array of hillocks or mesas grow at the interface between a Ag overlay and Pb-doped Bi2Sr2Ca1Cu2O8+δ grains during the ramp up to the reaction temperature. As viewed in an environmental scanning electron microscope, the Ag coated grains develop a texture that looks like ``chicken pox'' growing on the grains at about 700 °C. These hillocks are about 100 nm across and are spaced at about 500 to 1000 nm. If there is no Ag, this texture does not develop. Preliminary measurements indicate that the hillocks are a recrystallization of (Bi,Pb)2Sr2Ca1Cu2O8+δ, and are definitely not a Pb rich phase.

  7. GEOCHEMICAL PARTITIONING OF PB, ZN, CU, FE, AND MN ACROSS THE SEDIMENT-WATER INFERFACE IN LARGE LAKES

    EPA Science Inventory

    The early diagenetic remobilization of Mn, Fe, Zn, Cu, and Pb was evaluated by studying the geochemical partitioning of the metals among hydromorphic phases (as operationally defined by sequential-chemical extractions) in interfacial sediment (fluff) and in the sediment column, a...

  8. Characterization and adsorption performance of Pb(II) on CuO nanorods synthesized by the hydrothermal method

    SciTech Connect

    Arfaoui, Lobna; Kouass, Salah; Dhaouadi, Hassouna; Jebali, Raouf; Touati, Fathi

    2015-10-15

    Highlights: • The nanorods of CuO were synthesized by a hydrothermal route without any surfactant. • X-ray diffraction showed monoclinic structure with space group C{sub 2/c}. • The nanorods show relatively high adsorption capacity for the removal of Pb(II). • The adsorption kinetics could be fitted well by the pseudo-second-order model. • The equilibrium data can be fitted well using the Langmuir isotherm model - Abstract: Copper oxide (CuO) nanorods were synthesized by hydrothermal method. The detailed structural, compositional and optical characterization of this material was also evaluated with XRD, FT-IR, EDS, and UV–vis spectroscopy, which confirmed that the obtained nanorods are well-crystallized CuO and possess good optical properties. SEM and TEM studies revealed that the as-synthesized CuO nanorods are uniform with an average diameter of 17 nm. The adsorption activity of the CuO nanostructures was studied. The adsorption results showed that the CuO nanorods are an effective and efficient adsorbent for the removal of Pb(II) ions. The influence of various operational parameters such as the pH of the solution, the contact time and the initial concentrations were also studied and the results were discussed. The estimated maximum lead ion adsorption capacity of the CuO nanorods was found to be 188.67 mg g{sup −1} at an optimum pH of 6.

  9. Water pollution by Cu and Pb can adversely affect mallard embryonic development.

    PubMed

    Kertész, Virág; Bakonyi, Gábor; Farkas, Beáta

    2006-09-01

    The effects of heavy metal pollutants on aquatic birds have been widely studied in ecotoxicological investigations; however, the predominant focus has been on the postnatal period of life. Limited information on the adverse effects of metals to bird eggs is available. The possible toxic effects of lead and copper were studied in mallard eggs. After the accidental severe heavy metal pollution of the Tisa river (Hungary) in March 2000, these metals were detected in the highest concentration in both the water and the sediment, reaching far beyond acceptable concentrations. Pb treatment (2.9 mg/L) significantly increased the rate of mortality after a single immersion of the eggs into polluted water for 30 min. The rate of dead embryos significantly increased after the combined exposure to Cu and Pb (0.86 and 2.9 mg/L, respectively) both in the single- (once for 30 min) and in the multiple- (10s daily during first trimester of incubation) immersion groups. It was concluded that elevated metal concentrations similar to those found in the Tisa river after the tailing dam failure may cause toxic effects (mortality and teratogenicity) upon exposure of mallard eggs. PMID:16678261

  10. Power-Generation Characteristics After Vibration and Thermal Stresses of Thermoelectric Unicouples with CoSb3/Ti/Mo(Cu) Interfaces

    NASA Astrophysics Data System (ADS)

    Bae, Kwang Ho; Choi, Soon-Mok; Kim, Kyung-Hun; Choi, Hyoung-Seuk; Seo, Won-Seon; Kim, Il-Ho; Lee, Soonil; Hwang, Hae Jin

    2015-06-01

    Reliability tests for thermoelectric unicouples were carried out to investigate the adhesion properties of CoSb3/Ti/Mo(Cu) interfaces. The n-type In0.25 Co3.95Ni0.05Sb12 and p-type In0.25Co3FeSb12 bulks were prepared for fabricating a thermoelectric unicouple (one p- n couple) by an induction melting and a spark plasma sintering process. Mo-Cu alloy was selected as an electrode for the unicouples due to its high melting temperature and proper work function value. Many thermoelectric unicouples with the CoSb3/Ti/Mo(Cu) interfaces were fabricated with the proper brazing materials by means of a repeated firing process. Reliability of the unicouples with the interfaces was evaluated by a vibration test and a thermal cycling test. After the thermal cycling and vibration tests, the power-generation characteristics of the unicouples were compared with the unicouples before the tests. Even after the vibration test, electrical power with a power density of 0.5 W/cm2 was generated. The Ti-interlayer is considered as a possible candidate for making a reliable unicouple with high adhesion strength. With the thermal cycling test, the resistance of the unicouple increased and the electrical power from the unicouple decreased. A failure mode by the thermal cycling test was ascribed to a complex effect of micro-cracks originated from the thermal stress and oxidation problem of the thermoelectric materials; that is, a thick oxide layer more than 300 μm was detected after a high-temperature durability test of n-type In0.25Co3.95Ni0.05Sb12 material at 773 K in air for 7 days.

  11. Rapid solidification and dendrite growth of ternary Fe-Sn-Ge and Cu-Pb-Ge monotectic alloys

    NASA Astrophysics Data System (ADS)

    Zhang, Xuehua; Ruan, Ying; Wang, Weili; Wei, Bingbo

    2007-08-01

    The phase separation and dendrite growth characteristics of ternary Fe-43.9%Sn-10%Ge and Cu-35.5%Pb-5%Ge monotectic alloys were studied systematically by the glass fluxing method under substantial undercooling conditions. The maximum undercoolings obtained in this work are 245 and 257 K, respectively, for these two alloys. All of the solidified samples exhibit serious macrosegregation, indicating that the homogenous alloy melt is separated into two liquid phases prior to rapid solidification. The solidification structures consist of four phases including α-Fe, (Sn), FeSn and FeSn2 in Fe-43.9%Sn-10%Ge ternary alloy, whereas only (Cu) and (Pb) solid solution phases in Cu-35.5%Pb-5%Ge alloy under different undercoolings. In the process of rapid monotectic solidification, α-Fe and (Cu) phases grow in a dendritic mode, and the transition “dendrite→monotectic cell” happens when alloy undercoolings become sufficiently large. The dendrite growth velocities of α-Fe and (Cu) phases are found to increase with undercooling according to an exponential relation.

  12. The potential pool of Co, Ni, Cu, Pb and Cd organic complexing ligands in coastal and urban rain waters

    NASA Astrophysics Data System (ADS)

    Nimmo, Malcolm; Fones, Gary R.

    The detection of dissolved ACSV (adsorptive cathodic stripping voltammetry) Co, Ni, Cu, Cd and Pb in rain waters collected from an urban and a coastal site in the northwest of England is described. The presence of metal complexing organic ligands in rain waters is indicated with an overall percentage of ACSV non - labile dissolved metal of the total dissolved metal fraction ( = %ACSV nl/t) being 33 (33); 28 (35); 26 (32); 33 (25); 27 (34): for Co, Ni, Cu, Cd and Pb, respectively, for the urban site (and coastal site). ACSV metal lability is theoretically defined and is dependent upon the a-coefficient ( β' MAL [AL]) of the added ACSV ligand (AL). No major differences were observed between %ACSV nl/t metal fractions in rain waters collected at the two contrasting sites for all the metals considered. As Cu, Pb, Cd and Ni had values greater than 10 for their Ef crust (crustal enrichment factor), rain water collected from both sites had predominantly anthropic chemical characteristics. The commonality of the aerosol chemical characteristics at the two sites may account for the observed similar (relative to total metal concentrations) proportions of metal organic complexation at the two different sites. The general order of increasing organic associations was Cu = Pb = Ni < Co < Cd, although the analytical log α-coefficients ( β' MAL [AL]) for each metal were different (9.62—Ni; 9.27—Cu; 5.29—Co; 2.15—Pb; 1.13—Cd). Significant correlations were encountered between ACSV non - labile and total dissolved trace metal concentrations of the pooled data from both sites, again an indication of the similarity of the chemical characteristics of the scavenged soluble organic ligands associated with background aerosol material.

  13. Possible double magnetic phase transition in Dy5CuPb3

    NASA Astrophysics Data System (ADS)

    Tran, V. H.; Gulay, L. D.

    2006-03-01

    We have investigated the magnetic and transport properties of Dy5CuPb3 by magnetic susceptibility, electrical resistivity, magnetoresistance and thermoelectric power measurements. The compound crystallises in the hexagonal Hf5CuSn3-type structure (space group P63/mcm) and probably undergoes two successive magnetic transitions at TC=45.0±0.5 K and TN=6.5±0.5 K. The experimental data are indicative of a ferri- and antiferromagnetic types of the transitions, respectively. We attribute the double magnetic phase transition and the reduction of the magnetisation values at low temperatures to associate with the two non-equivalent magnetic sublattices of the Dy ions. We observed a large magnetoresistance value of -24% at temperatures in between TN and TC. The investigated compound has a negative thermoelectric power of -17 μV/K at 300 K. We interpret the overall behaviour of the S(T)-curve to two different mechanisms: magnetic and charge carrier diffusion.

  14. Preparation of 110K (Bi, Pb)-Sr-Ca-Cu-O superconductor from glass precursor

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.

    1989-01-01

    The Bi1.5Pb0.5Sr2Ca2Cu3O(x) glass, prepared by rapid quenching of the melt, showed T(sub g) of 383 C, crystallization temperature of approx. 446 C, melting temperature of approx. 855 C, and bulk density of 5.69 g/cu. cm. in air. The as-quenched glass was oxygen deficient. On heating in O2, it showed a slow, irreversible, and continuous weight gain starting at approx. 530 C. The influence of annealing conditions on the formation of various phases was investigated by XRD and electrical resistivity measurements. The 110K-T(sub c) phase did not form below 840 C. The amount of this phase increased with the sintering time at 840 C. A sample annealed at 840 C for 243 h in air and furnace cooled showed the highest T(sub c)(R=0) of 107.2K and transition width delta T(sub c)(10 to 90 percent) of approx. 2 K.

  15. Acid blue 29 decolorization and mineralization by anodic oxidation with a cold gas spray synthesized Sn-Cu-Sb alloy anode.

    PubMed

    do Vale-Júnior, Edilson; Dosta, Sergi; Cano, Irene Garcia; Guilemany, Josep Maria; Garcia-Segura, Sergi; Martínez-Huitle, Carlos Alberto

    2016-04-01

    The elevated cost of anodic materials used in the anodic oxidation for water treatment of effluents undermines the real application of these technologies. The study of novel alternative materials more affordable is required. In this work, we report the application of Sn-Cu-Sb alloys as cheap anodic material to decolorize azo dye Acid Blue 29 solutions. These anodes have been synthesized by cold gas spray technologies. Almost complete decolorization and COD abatement were attained after 300 and 600 min of electrochemical treatment, respectively. The influence of several variables such as supporting electrolyte, pH, current density and initial pollutant concentration has been investigated. Furthermore, the release and evolution of by-products was followed by HPLC to better understand the oxidative power of Sn-Cu-Sb electrodes. PMID:26802262

  16. Fabrication and characterization of a nanostructured TiO2/In2S3-Sb2S3/CuSCN extremely thin absorber (eta) solar cell

    NASA Astrophysics Data System (ADS)

    Huerta-Flores, Alí M.; García-Gómez, Nora A.; de la Parra-Arciniega, Salomé M.; Sánchez, Eduardo M.

    2016-08-01

    In this work we report the successful assembly and characterization of a TiO2/In2S3-Sb2S3/CuSCN extremely thin absorber solar cell. Nanostructured TiO2 deposited by screen printing on an ITO substrate was used as an n-type electrode. An ∼80 nm extremely thin layer of the system In2S3-Sb2S3 deposited by successive ionic layer adsorption and a reaction (silar) method was used as an absorber. The voids were filled with p-type CuSCN and the entire assembly was completed with a gold contact. The solar cell fabricated with this heterostructure showed an energy conversion efficiency of 4.9%, which is a promising result in the development of low cost and simple fabrication of solar cells.

  17. Preparation of CuSbS2 Thin Films by Co-Sputtering and Solar Cell Devices with Band Gap-Adjustable n-Type InGaN as a Substitute of ZnO

    NASA Astrophysics Data System (ADS)

    Chen, Wei-Liang; Kuo, Dong-Hau; Tuan, Thi Tran Anh

    2016-01-01

    CuSbS2 films were fabricated by co-sputtering with the (Cu + Sb2S3) target at powers of 50 W, 55 W, and 60 W and a Cu target at 2 W under the deposition temperature of 300°C for 2 h, followed by annealing at 350-450°C for 1 h under a Sb2S3 compensation disc to avoid the sulfur deficiency. The (Cu + Sb2S3) cermet target with the composition of Cu:Sb2S3 = 2:1 was formed by hot pressing. The effects of processing conditions on the growth behavior, microstructural characteristics, and electrical properties of CuSbS2 films were investigated. X-ray diffractometry showed that the films prepared by the (Cu + Sb2S3) target at 50 W and 55 W were single phases. The peaks located at 28.4°, 28.7°, and 29.9° were contributed from the (111), (410), and (301) diffraction peaks, respectively. The film prepared with the (Cu + Sb2S3) target at 60 W was Cu rich and had a high electrical conductivity of 180 S cm-1. The 55 W-deposited film was Cu stoichiometric and had low electrical conductivity of 0.05 S cm-1. The 50 W-deposited film with electrical conductivity of 0.24 S cm-1 was good for use as a solar cell device. The solar cell devices made of the p-CuSbS2/ n-ZnO system had an efficiency of 0.16%, while it was 0.76% for the p-CuSbS2/ n-In0.3Ga0.7N system with the InGaN made by reactive sputtering at 200°C instead of metal-organic chemical vapor deposition above 750°C. This replacement with InGaN for a solar cell device has led to a 4.75-fold increase in efficiency.

  18. The Transfiguration continental red-bed Cu-Pb-Zn-Ag deposit, Quebec Appalachians, Canada

    NASA Astrophysics Data System (ADS)

    Cabral, Alexandre Raphael; Beaudoin, Georges; Taylor, Bruce E.

    2009-04-01

    The Transfiguration Cu-Pb-Zn-Ag deposit, enclosed within reduced grey sandstone, is associated with continental red beds of the Lower Silurian Robitaille Formation in the Quebec Appalachians, Canada. The Robitaille Formation rests unconformably on foliated Cambro-Ordovician rocks. The unconformity is locally cut by barite veins. The basal unit of the Robitaille Formation comprises green wacke and pebble conglomerate, which locally contain calcite nodules. The latter have microstructures characteristic of alpha-type calcretes, such as “floating” fabrics, calcite-filled fractures (crystallaria) and circumgranular cracks. Massive, grey sandstone overlies the basal green wacke and pebble conglomerate unit, which is overlain, in turn, by red, fine-grained sandstone. Mineralisation occurred underneath the red sandstone unit, chiefly in the grey sandstone unit, as disseminated and veinlet sulphides. Chalcopyrite, the most abundant Cu sulphide, replaced early pyrite. Calcrete, disseminated carbonate and vein carbonate have stable isotope ratios varying from -7.5‰ to -1.1‰ δ13C and from 14.7‰ to 21.3‰ δ18O. The negative δ13C values indicate the oxidation of organic matter in a continental environment. Sulphur isotope ratios for pyrite, chalcopyrite and galena vary from -19‰ to 25‰ δ34S, as measured on mineral concentrates by a conventional SO2 technique. Laser-assisted microanalyses (by fluorination) of S isotopes in pyrite show an analogous range in δ34S values, from -21‰ to 25‰. Negative and positive δ34S values are compatible with bacterial sulphate reduction (BSR) in systems open and closed with respect to sulphate. We interpret similarly high δ34S values for sulphide concentrates (25.1‰) and for vein barite (26.2‰) to result from rapid and complete thermochemical reduction of pore-water sulphate. Two early to late diagenetic stages of mineralisation best explain the origin of the Transfiguration deposit. The first stage was characterised

  19. Infrared spectroscopy of undoped and Cu-doped (80-x)Sb2O3-20Li2O-xMoO3 glasses

    NASA Astrophysics Data System (ADS)

    Petkova, P.; Boubaker, K.; Vasilev, P.; Mustafa, M.; Yumak, A.; Touihri, H.; Soltani, M. T.

    2016-04-01

    In this work, the absorption spectra of the undoped and doped with 0.1% and 0.2% CuO2 glasses with the composition (80-x)Sb2O3-20Li2O-xMoO3 are measured in the spectral region 1300-1800 nm. The optical structure of Cu2+ is investigated and the energies of the electron transitions in this metal cation are determined. The spin-orbit interaction, Lattice Compatibility Theory (LCT) analyses and the influence of molybdenum are also discussed.

  20. A new phase in the Sr sbnd Pb sbnd Cu oxide system: The crystal structure of Sr 5- xPb 3+ xCu yO 12-δ

    NASA Astrophysics Data System (ADS)

    Kim, J. S.; Tang, X. X.; Manthiram, A.; Swinnea, J. S.; Steinfink, H.

    1990-03-01

    A single crystal with compositions Sr 4.79Pb 3.21Cu 0.66O 11.12 was grown from a reaction mixture of nominal composition 2 Pb:1 Sr:1 Cu that was fired at 860°C in air. Mr = 1304.6,hexagonal, P¯62 m, a = 10.072(3)Å, c = 3.542(3)Å, V = 311.2(4)Å 3, Z = 1, Dx = 6.96 g cm -3, λ = 0.71069A˚, μ = 645 cm -1, F(000) = 553.34,room temperature, R = 0.040for 323 unique reflections5σ( Fo).The Pb atoms are in octahedral coordination; the octahedra form a chain parallel to cby edge-sharing. Sr is coordinated by nine oxygen atoms that form a capped trigonal prism. The trigonal prisms form a chain parallel to cby face-sharing. TheSr/Pbsite is surrounded by seven oxygen ions. The polyhedron can be described as a tricapped trigonal prism with one edge of the prism missing. The octahedra and trigonal prisms articulate by corner sharing into a three-dimensional framework. Two crystallographically independent Cu atoms are disordered and occupy tetrahedral interstices. One oxygen site is partially occupied. The presence of Pb 2+ on the Pb site distorts the octahedron by lengthening two bonds to 2.44(3)A˚; the average of the other four bond lengths is 2.137(19)A˚. The Sr sbnd O bond lengths to the six apices of the prism are 2.632(14) and 2.935(3)A˚to the three capping atoms. The disorderedSr/Pb atom site has four oxygen neighbors at 2.544(17)A˚, two at 2.621(5)A˚, and one at 2.42(2)A˚. The compound is an electrical insulator.

  1. Stabilization of Pb²⁺ and Cu²⁺ contaminated firing range soil using calcined oyster shells and waste cow bones.

    PubMed

    Moon, Deok Hyun; Cheong, Kyung Hoon; Khim, Jeehyeong; Wazne, Mahmoud; Hyun, Seunghun; Park, Jeong-Hun; Chang, Yoon-Young; Ok, Yong Sik

    2013-05-01

    Pb(2+) and Cu(2+) contamination at army firing ranges poses serious environmental and health risks to nearby communities necessitating an immediate and prompt remedial action. In this study, a novel mixture of calcined oyster shells (COSs) and waste cow bones (WCBs) was utilized to immobilize Pb(2+) and Cu(2+) in army firing range soils. The effectiveness of the treatment was evaluated based on the Korean Standard leaching test. The treatment results showed that Pb(2+) and Cu(2+) immobilization in the army firing range soil was effective in significantly reducing Pb(2+) and Cu(2+) leachability upon the combined treatment with COS and WCB. A drastic reduction in Pb(2+) (99%) and Cu(2+) leachability (95%) was obtained as compared to the control sample, upon treatment with 5 wt.% COS and 5 wt.% WCB. The combination treatment of COS and WCB was more effective for Pb immobilization, than the treatment with COS or WCB alone. The 5 wt.% COS alone treatment resulted in 95% reduction in Cu(2+) leachability. The SEM-EDX results suggested that Pb(2+) and Cu(2+) immobilization was most probably associated with the formation of ettringite, pozzolanic reaction products and pyromorphite-like phases at the same time. PMID:23478128

  2. Effect of Crucible Diameter Reduction on the Convection, Macrosegregation, and Dendritic Morphology during Directional Solidification of Pb-2.2 Wt Pct Sb Alloy

    NASA Technical Reports Server (NTRS)

    Chen, Jun; Tewari, S. N.; Magadi, G.; DeGroh, H. C., III

    2003-01-01

    The Pb-2.2 wt pct Sb alloy has been directionally solidified in 1-, 2-, 3-, and 7-mm-diameter crucibles with planar and dendritic liquid-solid interface orphology. For plane front solidification, the experimentally observed macrosegregation along the solidified length follows the relationship proposed by Favier. Application of a 0.4 T transverse magnetic field has no effect on the extent of convection. Reducing the ampoule diameter appears to decrease the extent of convection. However, extensive convection is still present even in the 1-mm-diameter crucible. An extrapolation of the observed behavior indicated that nearly diffusive transport conditions require ampoules that are about 40 microns in diameter. Reduction of the crucible diameter does not appear to have any significant effect on the primary dendrite spacing. However, it results in considerable distortion of the dendrite morphology and ordering. This is especially true for the 1-mm diameter samples.

  3. Dielectric and piezoelectric properties of Bi2O3 added (Pb,Ca,Sr)(Ti,Mn,Sb)O3 ceramics sintered at low temperature

    NASA Astrophysics Data System (ADS)

    Kim, Dohyung; Yoo, Juhyun; Kim, Insung; Song, Jaesung

    2009-03-01

    In this study, in order to develop low temperature sintering ceramics for a thickness mode multilayer piezoelectric transformer, (Pb,Ca,Sr)(Ti,Mn,Sb)O3 ceramics were fabricated using Na2CO3, Li2CO3, MnO2, and Bi2O3 as sintering aids at 870, 900, and 930 °C. Their respective dielectric and piezoelectric properties were investigated according to the amount of Bi2O3 addition. At the sintering temperature of 900 °C, the optimum value was shown for the density of 6.94 g/cm3, thickness vibration mode electromechanical coupling factor (henceforth, kt) of 0.497, thickness vibration mode mechanical quality factor (henceforth, Qmt) of 3162, and dielectric constant (henceforth, ɛr) of 209 for thickness mode multilayer piezoelectric transformer application.

  4. Lanthanide contraction effect on crystal structures, magnetic, and dielectric properties in ordered double perovskites LnPbCoSbO{sub 6} (Ln = La, Pr, Nd)

    SciTech Connect

    Han, L.; Yao, C. G.; Meng, J. L.; Liang, Q. S.; Bai, Y. J.; Meng, F. Z.; Liu, X. J. E-mail: jmeng@ciac.ac.cn; Wu, X. J.; Meng, J. E-mail: jmeng@ciac.ac.cn

    2014-04-28

    The crystal structures, magnetic, and dielectric properties for the ordered double perovskites LnPbCoSbO{sub 6} (Ln = La, Pr, Nd) have been investigated. The crystal structure has been solved by Rietveld refinements of X-ray diffraction data in the monoclinic space group P2{sub 1}/n (No. 14). The Co{sup 2+} and Sb{sup 5+} ions are almost fully ordered over the B-site, and the octahedral framework displays significant tilting distortion according to the Glazer's tilt system a{sup –}a{sup –}c{sup +}. As the result of lanthanide contraction from La{sup 3+} to Nd{sup 3+}, the B-site sublattice distortions become stronger accompanying with the reduction of the tolerance factor and coordination number. The magnetization measurements show an antiferromagnetic ordering with large effective magnetic moments (μ{sub eff}) suggesting that the orbital component is significant. The maximum values of isothermal magnetization increase with the decrease in radii of rare earth ions, which is attributed to the weakening of antiferromagnetic interaction via Co{sup 2+}–O–Sb{sup 5+}–O–Co{sup 2+} paths. The dielectric constants present frequency dependence and monotonically decrease with the ionic radii reduction from La{sup 3+} to Nd{sup 3+} due to the suppression of electron transfer. These results indicate that the magnetic and dielectric properties can be tuned by controlling the degree of lattice distortion, which is realized by introducing different Ln{sup 3+} ions at the A-site.

  5. Influence of growth direction on the microstructure of unidirectionally solidified Cu Pb monotectic alloy using zone-melt technique

    NASA Astrophysics Data System (ADS)

    Aoi, Ichiro; Ishino, Makoto; Yoshida, Makoto; Fukunaga, Hideharu; Nakae, Hideo

    2001-02-01

    The influence of growth direction on the monotectic structure of the Cu-Pb alloy is studied. In order to examine the influence under a 1 g environment, both the upward (opposite to the direction of gravity) and downward (the direction of gravity) unidirectional solidifications (UDS) are carried out. In the case of the upward UDS, a banded structure, which consists of Pb-rich and Cu-rich layers, is observed. The L 2 droplets pile up in front of the solid/liquid interface. On the other hand, in the downward UDS, the irregularly shaped L 2 phase uniformly disperses in the specimen and no banded structure is found. The gravity macrosegregation of the L 2 liquid is observed at the bottom of the molten alloy in the downward solidified specimen. This is caused by the difference in the density between the L 1 and L 2 phases. Furthermore, a mechanism for the formation of a banded structure is suggested. This mechanism suggests that the coalesced L 2 phase covers the solid/liquid interface by producing a Pb-rich layer that permits an increase in the undercooling of the L 1/L 2 interface compared to the monotectic temperature. As nucleation of the α-Cu phase occurs on the Pb-rich layer, the coexisting three phases are then restored. The temperature at the growth front is also returned to the monotectic temperature. The repetition mentioned above will result in the banded structure found in the upward UDS.

  6. Trace metals (Cd, Pb, Cu, Zn and Ni) in sediment of the submarine pit Dragon ear (Soline Bay, Rogoznica, Croatia)

    NASA Astrophysics Data System (ADS)

    Kljaković-Gašpić, Zorana; Bogner, Danijela; Ujević, Ivana

    2009-08-01

    Vertical profiles of trace metal (Cd, Pb, Zn, Cu, Ni) concentrations, organic matter content, carbonate content and granulometric composition were determined in two sediment cores from the submarine pit Dragon Ear (Middle Adriatic). Concentrations of the analyzed metals (Cd: 0.06-0.12 mg kg-1, Pb: 28.5-67.3 mg kg-1, Zn: 17.0-65.4 mg kg-1, Cu: 21.1-51.9 mg kg-1, Ni: 27.8-40.2 mg kg-1) were in usual range for Adriatic carbonate marine sediments. Nevertheless, concentrations of Cu, Zn, and especially Pb in the upper layer of sediments (top 12 cm) were higher than in bottom layer, while Cd and Ni concentration profiles were uniform. Regression analysis and principal component analysis were used to interpret distribution of trace metals, organic matter and carbonate content in sediment cores. Results of both analysis showed that concentrations of all trace metals in the core below the entrance to the pit were significantly positively correlated with organic matter and negatively correlated with carbonate, while in the core more distant from the entrance only Pb showed significant positive correlation with organic matter. Obtained results indicated that, except for lead which was enriched in surface sediment, in the time of sampling (before the building of the nautical marina) investigated area belonged to unpolluted areas.

  7. Studies of biosorption of Pb2+, Cd2+ and Cu2+ from aqueous solutions using Adansonia digitata root powders.

    PubMed

    Ekere, N R; Agwogie, A B; Ihedioha, J N

    2016-01-01

    The potentials of Adansonia digitata root powders (ADRP) for adsorption of Pb(2+), Cd(2+) and Cu(2+) from aqueous solutions was investigated. Physico-chemical analysis of the adsorbent (ADRP) shows that hydroxyl, carbonyl and amino groups were predominant on the surface of the adsorbent. Scanning Electron Microscope (SEM) image revealed its high porosity and irregular pores in the adsorbent while the Energy Dispersive X-ray Spectrum showed the major element with 53.0% Nitrogen, 23.8% carbon, 9.1% calcium, 7.5% potassium and 6.6% magnesium present. The found optimal conditions were: initial concentration of the metal ions = 0.5 mg/L, pH = 5, contact time = 90 min, adsorbent dose = 0.4 g and particle size = 32 µm. Freundlich isotherm showed good fit for the adsorption of Pb(2+), Cd(2+) and Cu(2+). Dubinin-Radushkevich isotherm revealed that the adsorption processes were physisorption Cd(II) and Cu(II) but chemisorption with respect to Pb(II) ions. The kinetics and thermodynamic studies showed that Pseudo-second order and chemisorptions provided the best fit to the experimental data of Pb (II) ions only. Batch desorption result show that desorption in the acidic media for the metal ions were more rapid and over 90% of the metal ions were recovered from the biomass. PMID:26267780

  8. Pb solubility of the high-temperature superconducting phase Bi2Sr2Ca2Cu3O(10+d)

    NASA Technical Reports Server (NTRS)

    Kaesche, Stefanie; Majewski, Peter; Aldinger, Fritz

    1995-01-01

    For the nominal composition of Bi(2.27-x)Pb(x)Sr2 Ca2 Cu3 O(10+d) lead content was varied from x = 0.05 to 0.45. The compositions were examined between 830 and 890 C which is supposed to be the temperature range over which the so-called 2223 phase (Bi2Sr2Ca2Cu3O(10+d)) is stable. Only compositions between x = 0.18 to 0.36 could be synthesized in a single phase state. For x is greater than 0.36 a lead containing phase with a stoichiometry of Pb4(Sr,Ca)5CuO(d) is formed, for x is less than 0.18 mainly Bi2Sr2CaCu2O(10+d) and cuprates are the equilibrium phases. The temperature range for the 2223 phase was found to be 830 to 890 C but the 2223 phase has extremely varying cation ratios over this temperature range. Former single phase 2223 samples turn to multi phase samples when annealed at slightly higher or lower temperatures. A decrease in the Pb solubility with increasing temperature was found for the 2223 phase.

  9. Rapid and nondestructive measurement of labile Mn, Cu, Zn, Pb and As in DGT by using field portable-XRF.

    PubMed

    Chen, Zheng; Williams, Paul N; Zhang, Hao

    2013-09-01

    The technique of diffusive gradients in thin films (DGT) is often employed to quantify labile metals in situ; however, it is a challenge to perform the measurements in-field. This study evaluated the capability of field-portable X-ray fluorescence (FP-XRF) to swiftly generate elemental speciation information with DGT. Biologically available metal ions in environmental samples passively preconcentrate in the thin films of DGT devices, providing an ideal and uniform matrix for XRF nondestructive detection. Strong correlation coefficients (r > 0.992 for Mn, Cu, Zn, Pb and As) were obtained for all elements during calibration. The limits of quantitation (LOQ) for the investigated elements of FP-XRF on DGT devices are 2.74 for Mn, 4.89 for Cu, 2.89 for Zn, 2.55 for Pb, and 0.48 for As (unit: μg cm(-2)). When Pb and As co-existed in the solution trials, As did not interfere with Pb detection when using Chelex-DGT. However, there was a significant enhancement of the Pb reading attributed to As when ferrihydrite binding gels were tested, consistent with Fe-oxyhydroxide surfaces absorbing large quantities of As. This study demonstrates the value of the FP-XRF technique to rapidly and nondestructively detect the metals accumulated in DGT devices, providing a new and simple diagnostic tool for on-site environmental monitoring of labile metals/metalloids. PMID:23912422

  10. Gas-phase particle size distributions and lead loss during spray pyrolysis of (Bi,Pb)--Sr--Ca--Cu--O

    SciTech Connect

    Gurav, A.S.; Kodas, T.T.; Joutsensaari, J.; Kauppinen, E.I.; Zilliacus, R.

    1995-07-01

    Gas-phase particle size distributions and lead loss were measured during formation of (Bi,Pb)--Sr--Ca--Cu--O and pure PbO particles by spray pyrolysis at different temperatures. A differential mobility analyzer (DMA) in conjunction with a condensation particle counter (CPC) was used to monitor the gas-phase particle size distributions, and a Berner-type low-pressure impactor was used to obtain mass size distributions and a Berner-type low-pressure impactor was used to obtain mass size distributions and size-classified samples for chemical analysis. For (Bi,Pb)--Sr--Ca--Cu--O, as the processing temperature was raised from 200 to 700 {degree}C, the number average particle size decreased due to metal nitrate decomposition, intraparticle reactions forming mixed-metal oxides and particle densification. The geometric number mean particle diameter was 0.12 {mu}m at 200 {degree}C and reduced to 0.08 and 0.07 {mu}m, respectively, at 700 and 900 {degree}C. When the reactor temperature was raised from 700 and 800 {degree}C to 900 {degree}C, a large number ({similar_to}10{sup 7} no./cm{sup 3}) of new ultrafine particles were formed from PbO vapor released from the particles and the reactor walls. Particles made at temperatures up to 700 {degree}C maintained their initial stoichiometry over the whole range of particle size monitored, however; those made at 800 {degree}C and above were heavily depleted in lead in the size range 0.5--5.0 {mu}m. The evaporative losses of lead oxide from (Bi,Pb)--Sr--Ca--Cu--O particles were compared with the losses from PbO particles to gain insight into the pathways involved in lead loss and the role of intraparticle processes in controlling it.

  11. Arsenic, Sb and Bi contamination of soils, plants, waters and sediments in the vicinity of the Dalsung Cu-W mine in Korea.

    PubMed

    Jung, Myung Chae; Thornton, Iain; Chon, Hyo-Taek

    2002-08-01

    The objective of this study is to investigate environmental contamination derived from metalliferous mining activities. In the study area, the Dalsung Cu-W mine, soils, various crop plants, stream waters, sediments and particulates were sampled in and around the mine and analyzed for As, Sb and Bi by ICP-AES with a hydride generator. In addition, soil pH, cation exchange capacity, loss-on-ignition and soil texture were also measured. Concentrations of As, Sb and Bi in surface soils sampled in the mine dump sites averaged 2500, 54 and 436 microg g(-1), respectively. Relatively lower concentrations, however, were found in soils from alluvial and high land sites and household garden sites. Arsenic, Sb and Bi contents in plant samples varied depending upon their species and parts, with higher concentrations in spring onions, soybean leaves and perilla leaves and lower levels in red peppers, corn grains and jujube grains. These results confirm that elemental concentrations in plant leaves are much higher than those in plant grain. Elevated levels of As, Sb and Bi were also found in stream sediments sampled in the vicinity of the mine and decreased with distance from the mine. Concentrations in stream water samples ranged from 0.8 to 19.1 microg As l(-1) and from 0.3 to 8.4 microg Bi l(-1); all the samples contained less than 1.0 microg Sb l(-1). Because of very low particulate loading at the time of sampling, the metal contents in particulates were very low (< 8.2 microg As l(-1), < 0.22 microg Sb l(-1) and 2.8 microg Bi l(-1). This may be mainly due to the low solubility of those elements under moderately acidic and oxidizing conditions of the mining area. PMID:12186294

  12. Biosorption of Cu2+, Cd2+, Pb2+, and Zn2+ using dried marine green macroalga Caulerpa lentillifera.

    PubMed

    Pavasant, Prasert; Apiratikul, Ronbanchob; Sungkhum, Vimonrat; Suthiparinyanont, Prateep; Wattanachira, Suraphong; Marhaba, Taha F

    2006-12-01

    The sorption of Cu2+, Cd2+, Pb2+, and Zn2+ by a dried green macroalga Caulerpa lentillifera was investigated. The removal efficiency increased with pH. The analysis with FT-IR indicated that possible functional groups involved in metal sorption by this alga were O-H bending, N-H bending, N-H stretching, C-N stretching, C-O, SO stretching, and S-O stretching. The sorption of all metal ions rapidly reached equilibrium within 20min. The sorption kinetics of these metals were governed by external mass transfer and intraparticle diffusion processes. The sorption isotherm followed the Langmuir isotherm where the maximum sorption capacities was Pb2+>Cu2+>Cd2+>Zn2+. PMID:16330209

  13. Fabrication of Bi-(Pb)-Sr-Ca-Cu-O mono- and multifilamentary superconductors and improvement in critical current density

    NASA Astrophysics Data System (ADS)

    Sekine, H.; Inoue, K.; Maeda, H.; Numata, K.

    1989-09-01

    This paper describes procedures for the fabrication of the Bi-(Pb)-Sr-Ca-Cu-O superconducting material as tapes without sheathing and as multifilamentary wires and tapes with Ag sheathing, together with results from metallurgical studies and measurements of superconducting properties. Tape specimens of 0.5-1.0-mm thickness, prepared by combination and repetition of cold work and sintering, showed critical current density Jc as high as 5000 A/sq cm at 77 K, with good reproducibility and reliability. A 1330-filament Bi-Pb-Sr-Ca-Cu-O wire with an Ag sheath showed critical temperature of about 105 K, and a multifilamentary tape specimen showed Jc of 1050 A/sq cm at 77 K. The process of repetition of cold work and sintering had the effect of Jc enhancement on multifilamentary tapes.

  14. Assessment of the effects of Cr, Cu, Ni and Pb soil contamination by ecotoxicological tests.

    PubMed

    Maisto, Giulia; Manzo, Sonia; De Nicola, Flavia; Carotenuto, Rita; Rocco, Annamaria; Alfani, Anna

    2011-11-01

    This study aimed to assess soil quality by chemical and ecotoxicological investigations and to check the correspondence between soil metal concentrations and ecotoxicity. For these purposes, surface soils collected at four adjacent roadside urban parks and at a former industrial area were characterized for C/N, organic matter content, texture, and pH. Cr, Cu, Ni and Pb, chosen among the most representative soil metal contaminants, were measured as total content and as available and water soluble fractions. In addition, the total concentrations of the investigated metals were used to calculate two chemical indices: the contamination and the potential ecological risk factors. The toxicity of the investigated soils was evaluated by an ecotoxicity test battery carried out on both soil samples (Vibrio fischeri, Heterocypris incongruens and Sinapis alba) and elutriates (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum). The findings, both by the chemical and ecotoxicological approaches, would suggest that the soils with high metal contamination pose ecological risks. On the other hand, moderately metal contaminated soils did not exclude soil ecotoxicity. In fact, toxic effects were also highlighted in soils with low metal content, toxicity being affected by metal availability and soil characteristics. Moreover, the results suggest the importance of using a battery of tests to assess soil ecotoxicity. PMID:21918769

  15. High-density Bi-Pb-Sr-Ca-Cu-O superconductor prepared by rapid thermal melt processing

    SciTech Connect

    Moon, B.M.; Lalevic, B. ); Kear, B.H.; McCandlish, L.E.; Safari, A.; Meskoob, M.

    1989-10-02

    A high quality, dense Bi-Pb-Sr-Ca-Cu-O superconductor has been successfully synthesized by rapid thermal melt processing. Conventionally sintered pellets were melted at 1200 {degree}C, cooled rapidly, and then annealed. As-melted samples exhibited semiconductor behavior, which upon annealing became superconducting at 115 K ({ital T}{sub {ital c}}(zero)=105 K). A detailed study of various processing techniques has been carried out.

  16. Influence of gravity level and interfacial energies on dispersion-forming tendencies in hypermonotectic Cu-Pb-Al alloys

    NASA Technical Reports Server (NTRS)

    Andrews, J. B.; Curreri, P. A.; Sandlin, A. C.

    1988-01-01

    Results on the nondirectional solidification of several hypermonotectic Cu-Pb-Al alloys were obtained aboard NASA's KC-135 zero-gravity aircraft in order to determine the influence of interfacial energies and gravity levels on dispersion-forming tendencies. The Al content was systematially varied in the alloys. The dispersion-forming ability is correlated with gravity level during solidification, the interfacial energy between the immiscible phases, and the tendency for the minority immiscible phase to wet the walls of the crucible.

  17. Valorization of a treated soil via amendments: fractionation and oral bioaccessibility of Cu, Ni, Pb, and Zn.

    PubMed

    Zagury, Gerald J; Rincon Bello, Jhony A; Guney, Mert

    2016-04-01

    The present study aims to transform a treated soil (TS) into a more desirable resource by modifying physico-chemical properties via amendments while reducing toxic metals' mobility and oral bioaccessibility. A hydrocarbon-contaminated soil submitted to treatment (TS) but still containing elevated concentrations of Cu, Ni, Pb, and Zn has been amended with compost, sand, and Al2(SO4)3 to render it usable for horticulture. Characterization and sequential extraction were performed for TS and four amended mixtures (AM1-4). P and K availability and metal bioaccessibility were investigated in TS and AM2. Amendment improved soil properties for all mixtures and yielded a usable product (AM2 20 % TS, 49 % compost, 30 % sand, 1 % Al2(SO4)3) satisfying regulatory requirements except for Pb content. In particular, AM2 had improved organic matter (OM) and cation exchange capacity (CEC), highly increased P and K availability, and reduced total metal concentrations. Furthermore, amendment decreased metal mobile fraction likely to be plant-available (in mg kg(-1), assumed as soluble/exchangeable + carbonates fractions). For AM2, estimated Pb bioavailability decreased from 1.50 × 10(3) mg kg(-1) (TS) to 238 mg kg(-1) (52.4 % (TS) to 34.2 %). Bioaccessible concentrations of Cu, Ni, and Zn (mg kg(-1)) were lower in AM2 than in TS, but there was no significant decrease for Pb. The results suggest that amendment improved soil by modifying its chemistry, resulting in lower metal mobile fraction (in %, for Cu and Zn) and bioaccessibility (in %, for Cu only). Amending soils having residual metal contamination can be an efficient valorization method, indicating potential for reducing treatment cost and environmental burden by rendering disposal/additional treatment unnecessary. Further studies including plant bioavailability are recommended to confirm results. PMID:26969154

  18. Direct determination of Cu, Mn, Pb, and Zn in beer by thermospray flame furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Nascentes, Clésia C.; Kamogawa, Marcos Y.; Fernandes, Kelly G.; Arruda, Marco A. Z.; Nogueira, Ana Rita A.; Nóbrega, Joaquim A.

    2005-06-01

    In this work, thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) was employed for Cu, Mn, Pb, and Zn determination in beer without any sample digestion. The system was optimized and calibration was based on the analyte addition technique. A sample volume of 300 μl was introduced into the hot Ni tube at a flow-rate of 0.4 ml min -1 using 0.14 mol l -1 nitric acid solution or air as carrier. Different Brazilian beers were directly analyzed after ultrasonic degasification. Results were compared with those obtained by graphite furnace atomic absorption spectrometry (GFAAS). The detection limits obtained for Cu, Mn, Pb, and Zn in aqueous solution were 2.2, 18, 1.6, and 0.9 μg l -1, respectively. The relative standard deviations varied from 2.7% to 7.3% ( n=8) for solutions containing the analytes in the 25-50 μg l -1 range. The concentration ranges obtained for analytes in beer samples were: Cu: 38.0-155 μg l -1; Mn: 110-348 μg l -1, Pb: 13.0-32.9 μg l -1, and Zn: 52.7-226 μg l -1. Results obtained by TS-FF-AAS and GFAAS were in agreement at a 95% confidence level. The proposed method is fast and simple, since sample digestion is not required and sensitivity can be improved without using expensive devices. The TS-FF-AAS presented suitable sensitivity for determination of Cu, Mn, Pb, and Zn in the quality control of a brewery.

  19. Mapping of Cu and Pb Contaminations in Soil Using Combined Geochemistry, Topography, and Remote Sensing: A Case Study in the Le’an River Floodplain, China

    PubMed Central

    Chen, Yiyun; Liu, Yaolin; Liu, Yanfang; Lin, Aiwen; Kong, Xuesong; Liu, Dianfeng; Li, Xiran; Zhang, Yang; Gao, Yin; Wang, Dun

    2012-01-01

    Heavy metal pollution in soil is becoming a widely concerning environmental problem in China. The aim of this study is to integrate multiple sources of data, namely total Cu and Pb contents, digital elevation model (DEM) data, remote sensing image and interpreted land-use data, for mapping the spatial distribution of total Cu and Pb contamination in top soil along the Le’an River and its branches. Combined with geographical analyses and watershed delineation, the source and transportation route of pollutants are identified. Regions at high risk of Cu or Pb pollution are suggested. Results reveal that topography is the major factor that controls the spatial distribution of Cu and Pb. Watershed delineation shows evidence that the streamflow resulting from rainfall is the major carrier of metal pollutants. PMID:22754479

  20. Aging effects on the microstructure, surface characteristics and wettability of Cu pretinned with Sn-Pb solders

    SciTech Connect

    Linch, H.S.

    1993-11-01

    This study investigates effects of aging in air and argon at 170 C on Cu coupons which were pretinned with 75Sn-25Pb, 8Sn-92Pb, and 5Sn-95Pb solders. Coatings were applied using electroplating or hot dipping techniques. The coating thickness was controlled between 3 to 3{mu}m and the specimens were aged for 0 hours, 2 hours, 24 hours and 2 weeks. Wetting balance tests were used to evaluate the wettability of the test specimens. Microstructural development was evaluated using X-ray diffraction, energy dispersive X-ray and Auger spectroscopy, as well as optical and scanning electron microscopy. The wetting behavior of the test specimens is interpreted with respect to observed microstructural changes and as a function of aging time, solder composition, and processing conditions.

  1. Relation of pH and other soil variables to concentrations of Pb, Cu, Zn, Cd, and Se in earthworms

    USGS Publications Warehouse

    Beyer, W.N.; Hensler, G.L.; Moore, J.

    1987-01-01

    Various soil treatments (clay, composted peat, superphosphate, sulfur, calcium carbonate, calcium chloride, zinc chloride, selenous acid) were added to experimental field plots to test the effect of different soil variables on the concentrations of 5 elements in earthworms (Pb, Cu, Zn, Cd, Se). Concentrations of the 5 elements were related to 9 soil variables (soil Pb, soil Cu, soil Zn, pH, organic matter, P, K, Mg, and Ca) with linear multiple regression. Lead concentrations in earthworms were positively correlated with soil Pb and soil organic matter, and negatively correlated with soil pH and soil Mg, with an R2 of 64%. Se concentrations were higher in earthworms from plots amended with Se, and Zn concentrations were higher in earthworms from plots amended with Zn. However, none of the other soil variables had important effects on the concentrations of Cu, Zn, Cd and Se in earthworms. Although some significant statistical relations were demonstrated, the values of r2 of all relations (> 20%) were so low that they had little predictive value.

  2. Interactions of core-shell quantum dots with metal resistant bacterium Cupriavidus metallidurans: consequences for Cu and Pb removal.

    PubMed

    Slaveykova, Vera I; Pinheiro, José Paulo; Floriani, Magali; Garcia, Miguel

    2013-10-15

    In the present study we address the interactions of carboxyl-CdSe/ZnS core/shell quantum dots (QDs), as a model of water dispersible engineered nanoparticles, and metal resistant bacteria Cupriavidus metallidurans, largely used in metal decontamination. The results demonstrate that QDs with average hydrodynamic size of 12.9 nm adhere to C. metallidurans. The percentage of bacterial cells displaying QD-fluorescence increased proportionally with contact time and QD concentration in bacterial medium demonstrating the association of QDs with the metal resistant bacteria. No evidence of QD internalization into bacterial cytoplasm was found by transmission electron microscopy with energy dispersive X-ray spectrometry, however QD clusters of sizes between 20 and 50 nm were observed on the bacterial surface and in the bacterial periplasmic compartment; observations consistent with the losses of membrane integrity induced by QDs. The presence of 20 nM QDs induced about 2-fold increase in Cu and Pb uptake fluxes by C. metallidurans exposed to 500 nM Pb or Cu, respectively. Overall, the results of this work suggest that when present in mixture with Cu and Pb, low levels of QDs originating from possible incidental release or QD disposal could increase metal accumulation in metal resistant bacterium. PMID:23912077

  3. Synthesis of poly(aminopropyl/methyl)silsesquioxane particles as effective Cu(II) and Pb(II) adsorbents.

    PubMed

    Lu, Xin; Yin, Qiangfeng; Xin, Zhong; Li, Yang; Han, Ting

    2011-11-30

    Poly(aminopropyl/methyl)silsesquioxane (PAMSQ) particles have been synthesized by a one-step hydrolytic co-condensation process using 3-aminopropyltriethoxysilane (APTES) and methyltrimethoxysilane (MTMS) as precursors in the presence of base catalyst in aqueous medium. The amino functionalities of the particles could be controlled by adjusting the organosilanes feed ratio. The compositions of the amino-functionalized polysilsesquioxanes were confirmed by FT-IR spectroscopy, solid-state (29)Si NMR spectroscopy, and elemental analysis. The strong adsorbability of Cu(II) and Pb(II) ions onto PAMSQ particles was systematically examined. The effect of adsorption time, initial metal ions concentration and pH of solutions was studied to optimize the metal ions adsorbability of PAMSQ particles. The kinetic studies indicated that the adsorption process well fits the pseudo-second-order kinetics. Adsorption phenomena appeared to follow Langmuir isotherm. The PAMSQ particles demonstrate the highest Cu(II) and Pb(II) adsorption capacity of 2.29 mmol/g and 1.31 mmol/g at an initial metal ions concentration of 20mM, respectively. The PAMSQ particles demonstrate a promising application in the removal of Cu(II) and Pb(II) ions from aqueous solutions. PMID:21945683

  4. Crystal structure of the (Pb, Hg)Sr 2(Ca, Y)Cu 2O 7- δ superconductor

    NASA Astrophysics Data System (ADS)

    Liu, R. S.; Hu, S. F.; Chen, D. H.; Shy, D. S.; Jefferson, D. A.

    1994-03-01

    Bulk superconductivity up to 90 K has been achieved in the Hg containing cuprate (Pb, Hg)Sr 2(Ca 1- xY x)Cu 2O 7- δ when x=0.3, which has the highest Tc among the Pb based materials. The crystal structure of the newly discovered Hg containing Pb based 1212 phase has been investigated by Rietveld analysis of X-ray powder diffraction (XRD) data, selected area electron diffraction (SAED) and high-resolution electron microscopy (HREM). We have identified the phase responsible for superconductivity in the so-called 1212 phase with a space group of P4/mmm and lattice constants of a=3.8166(1) Å and c=11.9484(4) Å for the x=0.5 sample. A disordering of the hole reservoir layer (Pb, Hg) due to the displacement of the oxygen ions and Pb/ Hg ions from their ideal positions of (0.5, 0.5, 0) to (0.39, 0.5, 0) and from (0, 0, 0) to (0.044, 0, 0), respectively, was found in the XRD refinement of the x=0.5 sample. This displacement may have given rise to the appearance of superlattice spots along the [104] ∗ direction with a commensurate modulation factor of 8 in the electron-diffraction pattern viewed down [010]. Moreover, mutual substitutions of cations (≈19% Cu in the Pb/Hg sites and ≈9% Hg in the Ca/Y sites) have been found in the sample.

  5. Influence of pyrolytic and non-pyrolytic rice and castor straws on the immobilization of Pb and Cu in contaminated soil.

    PubMed

    Rizwan, Muhammad Shahid; Imtiaz, Muhammad; Chhajro, Muhammad Afzal; Huang, Guoyong; Fu, Qingling; Zhu, Jun; Aziz, Omar; Hu, Hongqing

    2016-11-01

    Soil contamination with heavy metals has become a global environmental health concern. In the present study, European Community Bureau of Reference (BCR) sequential extraction and toxicity characteristic leaching procedure (TCLP) techniques were used to evaluate the Pb and Cu subsequent transformations, immobilizing impact of pyrolytic and non-pyrolytic rice and castor straws and their efficiency to reduce the metals mobility and leachability in the polluted soil. Obtained results highlight the potential of biochar over non-pyrolytic residues to enhance the immobilization of Pb and Cu in the soil. Castor leaves-derived biochar (CLB), castor stem-derived biochar (CSB), and rice straw-derived biochar (RSB) prominently decreased the mobility (acid-soluble fraction) of Pb 49.8%, 31.1%, and 31.9%, respectively, while Cu decreased 15.8%, 11.5%, and 12%, respectively, as compare to control. Sequential extraction showed that biochar treatments prominently modified the proportioning of Pb and Cu from acid soluble to a less bioavailable fraction and increased the geochemical stability in the polluted soil as compared to relative feedstocks as well as the controlled soil. Additionally, the soil pH increased markedly after the addition of biochar. Compared with control, the TCLP-extractable Pb and Cu were reduced to 29.2-41.4% and 5.7-22.8% from the soil respectively by the application of CLB. The immobilization and reduction in leachability of Pb and Cu were correlated with the soil pH. The biochar effect on the Pb immobilization was much better as compared to Cu in co-contaminated soil. Overall addition of CLB offered the best results and could be effective in both Pb and Cu immobilization thereby reducing their mobility and bioavailability in the co-contaminated soil. PMID:26934087

  6. Structure, infrared and Raman spectroscopic studies of newly synthetic AII(SbV0.50FeIII0.50)(PO4)2 (Adbnd Ba, Sr, Pb) phosphates with yavapaiite structure

    NASA Astrophysics Data System (ADS)

    Aatiq, Abderrahim; Tigha, My Rachid; Fakhreddine, Rachid; Bregiroux, Damien; Wallez, Gilles

    2016-08-01

    The synthesis and structural study of three new AII(SbV0.5FeIII0.5)(PO4)2 (Adbnd Ba, Sr, Pb) phosphates belonging to the Asbnd Sbsbnd Fesbnd Psbnd O system were reported here for the first time. Structures of [Ba], [Sr] and [Pb] compounds, obtained by solid state reaction in air atmosphere, were determined at room temperature from X-ray powder diffraction using the Rietveld method. BaII(SbV0.5FeIII0.5)(PO4)2 features the yavapaiite-type structure, with space group C2/m, Z = 2 and a = 8.1568(4) Å; b = 5.1996(3) Å c = 7.8290(4) Å; β = 94.53(1)°. AII(SbV0.5FeIII0.5)(PO4)2 (Adbnd Sr, Pb) compounds have a distorted yavapaiite structure with space group C2/c, Z = 4 and a = 16.5215(2) Å; b = 5.1891(1) Å c = 8.0489(1) Å; β = 115.70(1)° for [Sr]; a = 16.6925(2) Å; b = 5.1832(1) Å c = 8.1215(1) Å; β = 115.03(1)° for [Pb]. Raman and Infrared spectroscopic study was used to obtain further structural information about the nature of bonding in selected compositions.

  7. Absence of Jahn-Teller transition in the hexagonal Ba3CuSb2O9 single crystal.

    PubMed

    Katayama, Naoyuki; Kimura, Kenta; Han, Yibo; Nasu, Joji; Drichko, Natalia; Nakanishi, Yoshiki; Halim, Mario; Ishiguro, Yuki; Satake, Ryuta; Nishibori, Eiji; Yoshizawa, Masahito; Nakano, Takehito; Nozue, Yasuo; Wakabayashi, Yusuke; Ishihara, Sumio; Hagiwara, Masayuki; Sawa, Hiroshi; Nakatsuji, Satoru

    2015-07-28

    With decreasing temperature, liquids generally freeze into a solid state, losing entropy in the process. However, exceptions to this trend exist, such as quantum liquids, which may remain unfrozen down to absolute zero owing to strong quantum entanglement effects that stabilize a disordered state with zero entropy. Examples of such liquids include Bose-Einstein condensation of cold atoms, superconductivity, quantum Hall state of electron systems, and quantum spin liquid state in the frustrated magnets. Moreover, recent studies have clarified the possibility of another exotic quantum liquid state based on the spin-orbital entanglement in FeSc2S4. To confirm this exotic ground state, experiments based on single-crystalline samples are essential. However, no such single-crystal study has been reported to date. Here, we report, to our knowledge, the first single-crystal study on the spin-orbital liquid candidate, 6H-Ba3CuSb2O9, and we have confirmed the absence of an orbital frozen state. In strongly correlated electron systems, orbital ordering usually appears at high temperatures in a process accompanied by a lattice deformation, called a static Jahn-Teller distortion. By combining synchrotron X-ray diffraction, electron spin resonance, Raman spectroscopy, and ultrasound measurements, we find that the static Jahn-Teller distortion is absent in the present material, which indicates that orbital ordering is suppressed down to the lowest temperatures measured. We discuss how such an unusual feature is realized with the help of spin degree of freedom, leading to a spin-orbital entangled quantum liquid state. PMID:26170280

  8. Alleviation of Cu and Pb rhizotoxicities in cowpea (Vigna unguiculata) as related to ion activities at root-cell plasma membrane surface.

    PubMed

    Kopittke, Peter M; Kinraide, Thomas B; Wang, Peng; Blamey, F Pax C; Reichman, Suzie M; Menzies, Neal W

    2011-06-01

    Cations, such as Ca and Mg, are generally thought to alleviate toxicities of trace metals through site-specific competition (as incorporated in the biotic ligand model, BLM). Short-term experiments were conducted with cowpea (Vigna unguiculata L. Walp.) seedlings in simple nutrient solutions to examine the alleviation of Cu and Pb toxicities by Al, Ca, H, Mg, and Na. For Cu, the cations depolarized the plasma membrane (PM) and reduced the negativity of ψ(0)(o) (electrical potential at the outer surface of the PM) and thereby decreased {Cu(2+)}(0)(o) (activity of Cu(2+) at the outer surface of the PM). For Pb, root elongation was generally better correlated to the activity of Pb(2+) in the bulk solution than to {Pb(2+)}(0)(o). However, we propose that the addition of cations resulted in a decrease in {Pb(2+)}(0)(o) but a simultaneous increase in the rate of Pb uptake (due to an increase in the negativity of E(m,surf), the difference in potential between the inner and outer surfaces of the PM) thus offsetting the decrease in {Pb(2+)}(0)(o). In addition, Ca was found to alleviate Pb toxicity through a specific effect. Although our data do not preclude site-specific competition (as incorporated in the BLM), we suggest that electrostatic effects have an important role. PMID:21563792

  9. Low-Temperature Bonding of Bi0.5Sb1.5Te3 Thermoelectric Material with Cu Electrodes Using a Thin-Film In Interlayer

    NASA Astrophysics Data System (ADS)

    Lin, Yan-Cheng; Yang, Chung-Lin; Huang, Jing-Yi; Jain, Chao-Chi; Hwang, Jen-Dong; Chu, Hsu-Shen; Chen, Sheng-Chi; Chuang, Tung-Han

    2016-09-01

    A Bi0.5Sb1.5Te3 thermoelectric material electroplated with a Ni barrier layer and a Ag reaction layer was bonded with a Ag-coated Cu electrode at low temperatures of 448 K (175 °C) to 523 K (250 °C) using a 4- μm-thick In interlayer under an external pressure of 3 MPa. During the bonding process, the In thin film reacted with the Ag layer to form a double layer of Ag3In and Ag2In intermetallic compounds. No reaction occurred at the Bi0.5Sb1.5Te3/Ni interface, which resulted in low bonding strengths of about 3.2 MPa. The adhesion of the Bi0.5Sb1.5Te3/Ni interface was improved by precoating a 1- μm Sn film on the surface of the thermoelectric element and preheating it at 523 K (250 °C) for 3 minutes. In this case, the bonding strengths increased to a range of 9.1 to 11.5 MPa after bonding at 473 K (200 °C) for 5 to 60 minutes, and the shear-tested specimens fractured with cleavage characteristics in the interior of the thermoelectric material. The bonding at 448 K (175 °C) led to shear strengths ranging from 7.1 to 8.5 MPa for various bonding times between 5 and 60 minutes, which were further increased to the values of 10.4 to 11.7 MPa by increasing the bonding pressure to 9.8 MPa. The shear strengths of Bi0.5Sb1.5Te3/Cu joints bonded with the optimized conditions of the modified solid-liquid interdiffusion bonding process changed only slightly after long-term exposure at 473 K (200 °C) for 1000 hours.

  10. Low-Temperature Bonding of Bi0.5Sb1.5Te3 Thermoelectric Material with Cu Electrodes Using a Thin-Film In Interlayer

    NASA Astrophysics Data System (ADS)

    Lin, Yan-Cheng; Yang, Chung-Lin; Huang, Jing-Yi; Jain, Chao-Chi; Hwang, Jen-Dong; Chu, Hsu-Shen; Chen, Sheng-Chi; Chuang, Tung-Han

    2016-07-01

    A Bi0.5Sb1.5Te3 thermoelectric material electroplated with a Ni barrier layer and a Ag reaction layer was bonded with a Ag-coated Cu electrode at low temperatures of 448 K (175 °C) to 523 K (250 °C) using a 4-μm-thick In interlayer under an external pressure of 3 MPa. During the bonding process, the In thin film reacted with the Ag layer to form a double layer of Ag3In and Ag2In intermetallic compounds. No reaction occurred at the Bi0.5Sb1.5Te3/Ni interface, which resulted in low bonding strengths of about 3.2 MPa. The adhesion of the Bi0.5Sb1.5Te3/Ni interface was improved by precoating a 1-μm Sn film on the surface of the thermoelectric element and preheating it at 523 K (250 °C) for 3 minutes. In this case, the bonding strengths increased to a range of 9.1 to 11.5 MPa after bonding at 473 K (200 °C) for 5 to 60 minutes, and the shear-tested specimens fractured with cleavage characteristics in the interior of the thermoelectric material. The bonding at 448 K (175 °C) led to shear strengths ranging from 7.1 to 8.5 MPa for various bonding times between 5 and 60 minutes, which were further increased to the values of 10.4 to 11.7 MPa by increasing the bonding pressure to 9.8 MPa. The shear strengths of Bi0.5Sb1.5Te3/Cu joints bonded with the optimized conditions of the modified solid-liquid interdiffusion bonding process changed only slightly after long-term exposure at 473 K (200 °C) for 1000 hours.

  11. The crystal structure of the new ternary antimonide Dy{sub 3}Cu{sub 20+x}Sb{sub 11-x} (x{approx}2)

    SciTech Connect

    Fedyna, L.O.; Bodak, O.I. . E-mail: bodak@franko.lviv.ua; Fedorchuk, A.O.; Tokaychuk, Ya.O.

    2005-06-15

    New ternary antimonide Dy{sub 3}Cu{sub 20+x}Sb{sub 11-x} (x{approx}2) was synthesized and its crystal structure was determined by direct methods from X-ray powder diffraction data (diffractometer DRON-3M, CuK{alpha}-radiation, R{sub I}=6.99%,R{sub p}=12.27%,R{sub wp}=11.55%). The compound crystallizes with the own cubic structure type: space group F4-bar 3m, Pearson code cF272, a=16.6150(2)A,Z=8. The structure of the Dy{sub 3}Cu{sub 20}Sb{sub 11-x} (x{approx}2) can be obtained from the structure type BaHg{sub 11} by doubling of the lattice parameter and subtraction of 16 atoms. The studied structure was compared with the structures of known compounds, which crystallize in the same space group with similar cell parameters.

  12. Structure and opoelectronic properies of P-CuSbS2 and N-ZnOxS1-x thin filims synthesiszed by tbds sulfurization mrthod for hetrojunction solar cells

    NASA Astrophysics Data System (ADS)

    Verma, Avinav

    Thin film Hetrojunction solar cell using CuSbS2 as p-type absorber material and ZnOxS1-x/ZnO n-type buffer layer material using magnetron sputtering and three gun sputtering. TBDS (di-tert butyle disulfide) sulfurization material was used in CVD (chemical vapor deposition) technique with time dependence. We investigated for making martial using TBDS which is low cost material. For ZnOxS1-x optical transmission, XRD, Raman spectroscopy and XPS was studied to learn about the material properties. Band gap calculation was taken in place to observe the change in band gap. XRD was to observe the change in crystal structure and Raman was to see the bonding properties of the material. XPS was done to check the depth profile of 6hr sulfurized ZnOxS1-x sample to see the compound ratio. For CuSbS2 optical transmission, XRD and Raman spectroscopy was done. The characterization techniques were used to make an assurance that the sample which I made were CuSbS2 or not. Also we increase the Cu and Sb ratio from original thickness (~480nm) to see the characteristics results using same characterization technique as CuSbS2.

  13. Origin of epithermal Ag-Au-Cu-Pb-Zn mineralization in Guanajuato, Mexico

    NASA Astrophysics Data System (ADS)

    Mango, Helen; Arehart, Greg; Oreskes, Naomi; Zantop, Half

    2014-01-01

    The Guanajuato epithermal district is one of the largest silver producers in Mexico. Mineralization occurs along three main vein systems trending dominantly northwest-southeast: the central Veta Madre, the La Luz system to the northwest, and the Sierra system to the east. Mineralization consists dominantly of silver sulfides and sulfosalts, base metal sulfides (mostly chalcopyrite, galena, sphalerite, and pyrite), and electrum. There is a broad zonation of metal distribution, with up to 10 % Cu+Pb+Zn in the deeper mines along the northern and central portions of the Veta Madre. Ore occurs in banded veins and breccias and as stockworks, with gangue composed dominantly of quartz and calcite. Host rocks are Mesozoic sedimentary and intrusive igneous rocks and Tertiary volcanic rocks. Most fluid inclusion homogenization temperatures are between 200 and 300 °C, with salinities below 4 wt.% NaCl equivalent. Fluid temperature and salinity decreased with time, from 290 to 240 °C and from 2.5 to 1.1 wt.% NaCl equivalent. Relatively constant fluid inclusion liquid-to-vapor ratios and a trend of decreasing salinity with decreasing temperature and with increasing time suggest dilution of the hydrothermal solutions. However, evidence of boiling (such as quartz and calcite textures and the presence of adularia) is noted along the Veta Madre, particularly at higher elevations. Fluid inclusion and mineralogical evidence for boiling of metal-bearing solutions is found in gold-rich portions of the eastern Sierra system; this part of the system is interpreted as the least eroded part of the district. Oxygen, carbon, and sulfur isotope analysis of host rocks, ore, and gangue minerals and fluid inclusion contents indicate a hydrothermal fluid, with an initial magmatic component that mixed over time with infiltrating meteoric water and underwent exchange with host rocks. Mineral deposition was a result of decreasing activities of sulfur and oxygen, decreasing temperature, increasing p

  14. Complex, multiple ore fluids in the world class southeast Missouri Pb-Zn-Cu MVT deposits: Sulfur isotope evidence

    SciTech Connect

    Burstein, I.B.; Shelton, K.L. ); Gregg, J.M.; Hagni, R.D. . Dept. of Geology Geophysics)

    1993-03-01

    More than 625 sulfur isotope data from all of the mines in the Viburnum Trend Pb-Zn-Cu MVT district of southeast Missouri have identified large temporal variations of sulfur isotope composition within the complex mineral paragenesis of each mine as well as large spatial variations in sulfur isotope composition within and among mines. The general trend of [delta][sup 34]S values with increasing paragenetic time is: Early pyrite, [minus]9 to [minus]1[per thousand]; Early bornite-chalcopyrite, [minus]9 to +16[per thousand]; Massive chalcopyrite, [minus]14 to +9[per thousand]; Main sphalerite, +12 to +26[per thousand]; Cuboctahedral galena, +5 to +22[per thousand]; Main marcasite, [minus]19 to +9[per thousand]; Cubic galena, [minus]2 to +13[per thousand] Late sphalerite, +6 to +13[per thousand]; Late marcasite, +10 to +19[per thousand]; Late chalcopyrite, +2 to +33[per thousand]. Spatial correlation of [delta][sup 34]S values of the Main stages of sulfide mineralization in the West Fork mine may indicate that the cuboctahedral galena in this mine was precipitated from a Pb-rich, S-poor fluid that incorporated sulfur from reaction with earlier marcasite. In the rest of the district, ore precipitation may have occurred by mixing of Pb-rich, S-poor fluids with Pb-poor, S-rich fluids. Complex mineral parageneses and sulfur isotope systematics within the southeast Missouri Pb-Zn-Cu MVT deposits are compatible with multiple, metal-specific fluids and multiple precipitation mechanisms, as well as multiple sulfur sources.

  15. Origin of a carbonate-hosted Fe-Mn-(Ba-As-Pb-Sb-W) deposit of Långban-type in central Sweden

    NASA Astrophysics Data System (ADS)

    Holtstam, D.; Mansfeld, J.

    2001-10-01

    The Sjögruvan deposit is one of the Långban-type Fe-Mn oxide deposits hosted by marble interbeds within Svecofennian metavolcanic rocks in the Bergslagen region, central Sweden. Mineralogical and geochemical studies have been carried out to clarify the premetamorphic origin of this type of deposit, which is set apart from most other Mn mineralizations by a significant enrichment in Ba, As, Sb, Pb, W and Be contained by various oxyminerals. The principal ore types at Sjögruvan are (1) hematite+quartz±magnetite, (2) hausmannite+calcite+tephroite and (3) braunite+celsian+phlogopite. The Mn ores are compositionally akin to modern Mn deposits formed by submarine hydrothermal processes (with a high Mn/Fe ratio and low contents of Co, Ni, Th, U and REE) and likely owe their existence to similar mechanisms of formation. Pb isotope data indicate that the metal source and timing of deposition is similar to the major stratabound base-metal and iron deposits in Bergslagen. All the key elements have been leached from the local felsic volcanic units and were deposited on the sea floor; the excellent Mn-Fe separation occurred in an Eh-pH gradient that essentially corresponded to the mixing zone of hydrothermal solutions and seawater. The braunite ore is chemically distinct from the hausmannite ore, with a high concentration of refractory elements (Al, Ti, Zr) and a positive Ce anomaly, which indicate a detrital/hydrogenetic contribution to its protolith. Carbon isotope (δ13C) values around 0‰ (relative PDB) suggest that carbonates in the deposit formed directly from seawater.

  16. Potential hyperaccumulation of Pb, Zn, Cu and Cd in endurant plants distributed in an old smeltery, northeast China

    NASA Astrophysics Data System (ADS)

    Cui, Shuang; Zhou, Qixing; Chao, Lei

    2007-01-01

    The absorption and accumulation of Pb, Zn, Cu and Cd in some endurant weed plant species that survived in an old smeltery in Liaoning, China, were systematically investigated. Potential hyperaccumulative characteristics of these species were also discussed. The results showed that metal accumulation in plants differed with species, tissues and metals. Endurant weed plants growing in this contaminated site exhibited high metal adaptability. Both the metal exclusion and detoxification tolerance strategies were involved in the species studied. Seven species for Pb and four species for Cd were satisfied for the concentration time level standard for hyperaccumulator. Considering translocation factor (TF) values, one species for Pb, seven species for Zn, two species for Cu and five species for Cd possessed the characteristic of hyperaccumulator. Particularly, Abutilon theophrasti Medic, exhibited strong accumulative ability to four heavy metals. Although enrichment coefficients of all samples were lesser than 1 and the absolute concentrations didn’t reach the standard, species mentioned above were primarily believed to be potential hyperaccumulators.

  17. Geological, fluid inclusion and isotopic studies of the Yinshan Cu-Au-Pb-Zn-Ag deposit, South China: Implications for ore genesis and exploration

    NASA Astrophysics Data System (ADS)

    Wang, Guo-Guang; Ni, Pei; Wang, Ru-Cheng; Zhao, Kui-Dong; Chen, Hui; Ding, Jun-Ying; Zhao, Chao; Cai, Yi-Tao

    2013-09-01

    The Yinshan Cu-Au-Pb-Zn-Ag deposit is located in Dexing, South China. Ore bodies are primarily hosted in low-grade phyllite of the Neoproterozoic Shuangqiaoshan Group along EW- and NNW-striking fault zones. Pb-Zn-Ag mineralization is dictated by Jurassic rhyolitic quartz porphyries (ca. 172 Ma), whereas Cu-Au mineralization is associated with Jurassic dacite porphyries (ca. 170 Ma). The main ore minerals are pyrite, chalcopyrite, galena, sphalerite, tetrahedrite-tennatite, gold, silver, and silver sulphosalt, and the principal gangue minerals are quartz, sericite, calcite, and chlorite. Two-phase liquid-rich (type I), two-phase vapor-rich (type II), and halite-bearing (type III) fluid inclusions can be observed in the hydrothermal quartz-sulfides veins. Type I inclusions are widespread and have homogenization temperatures of 187-303 °C and salinities of 4.2-9.5 wt.% NaCl equivalent in the Pb-Zn-Ag mineralization, and homogenization temperatures of 196-362 °C and salinities of 3.5-9.9 wt.% NaCl equivalent in the Cu-Au mineralization. The pervasive occurrence of type I fluid inclusions with low-moderate temperatures and salinities implies that the mineralizing fluids formed in epithermal environments. The type II and coexisting type III inclusions, from deeper levels below the Cu-Au ore bodies, share similar homogenization temperatures of 317-448 °C and contrasting salinities of 0.2-4.2 and 30.9-36.8 wt.% NaCl equivalent, respectively, which indicates that boiling processes occurred. The sulfur isotopic compositions of sulfides (δ34S = -1.7‰ to +3.2‰) suggest a homogeneous magmatic sulfur source. The lead isotopes of sulfides (206Pb/204Pb = 18.01-18.07; 207Pb/204Pb = 15.55-15.57; and 208Pb/204Pb = 38.03-38.12) are consistent with those of volcanic-subvolcanic rocks (206Pb/204Pb = 18.03-18.10; 207Pb/204Pb = 15.56-15.57; and 208Pb/204Pb = 38.02-38.21), indicating a magmatic origin for lead in the ore. The oxygen and hydrogen isotope compositions (δ18O = +7.8

  18. Chelating stability of an amphoteric chelating polymer flocculant with Cu(II), Pb(II), Cd(II), and Ni(II)

    NASA Astrophysics Data System (ADS)

    Liu, Lihua; Li, Yanhong; Liu, Xing; Zhou, Zhihua; Ling, Yulin

    2014-01-01

    The absorption spectra of Cu2+, Pb2+, Cd2+, and Ni2+ chelates of an amphoteric chelating polymer flocculant (ACPF) were measured by ultraviolet spectrophotometry, and their compositions and stability constants (β) were calculated. ACPF exhibited three apparent absorption peaks at 204, 251, and 285 nm. The sbnd CSS- group of ACPF reacted with Cu2+, Ni2+, Pb2+, and Cd2+ to form ACPF-Cu2+, ACPF-Ni2+, ACPF-Pb2+, and ACPF-Cd2+ chelates, respectively, according to a molar ratio of 2:1. The maximum absorption peaks of ACPF-Cu2+, ACPF-Ni2+, ACPF-Pb2+, and ACPF-Cd2+ appeared at 319, 326, 310, and 313.5 nm, respectively. The maximum absorption peaks of the chelates showed significant red shifting compared with the absorption peaks of ACPF. The β values of the ACPF-Cu2+, ACPF-Pb2+, ACPF-Cd2+, and ACPF-Ni2+ chelates were (1.37 ± 0.35) × 1012, (3.26 ± 0.39) × 1011, (2.05 ± 0.27) × 1011, and (3.04 ± 0.45) × 1010, respectively. The leaching rate of heavy metal ions from the chelating precipitates decreased with increasing pH. ACPF-Cu2+, ACPF-Ni2+, ACPF-Pb2+, and ACPF-Cd2+ were very stable at pH ⩾ 5.6. Cu2+, Ni2+, Pb2+, and Cd2+ concentrations in the leaching liquors were lower than the corresponding limits specified by the Integrated Wastewater Discharge Standard of China.

  19. Testing WHAM-FTOX with laboratory toxicity data for mixtures of metals (Cu, Zn, Cd, Ag, Pb).

    PubMed

    Tipping, Edward; Lofts, Stephen

    2015-04-01

    The Windermere humic aqueous model using the toxicity function (WHAM-FTOX ) describes cation toxicity to aquatic organisms in terms of 1) accumulation by the organism of metabolically active protons and metals at reversible binding sites, and 2) differing toxic potencies of the bound cations. Cation accumulation (νi , in mol g(-1) ) is estimated through calculations with the WHAM chemical speciation model by assuming that organism binding sites can be represented by those of humic acid. Toxicity coefficients (αi ) are combined with νi to obtain the variable FTOX (= Σ αi νi ) which, between lower and upper thresholds (FTOX,LT , FTOX,UT ), is linearly related to toxic effect. Values of αi , FTOX,LT , and FTOX,LT are obtained by fitting toxicity data. Reasonable fits (72% of variance in toxic effect explained overall) were obtained for 4 large metal mixture acute toxicity experiments involving daphnids (Cu, Zn, Cd), lettuce (Cu, Zn, Ag), and trout (Zn, Cd, Pb). Strong nonadditive effects, most apparent in results for tests involving Cd, could be explained approximately by purely chemical competition for metal accumulation. Tentative interpretation of parameter values obtained from these and other experimental data suggests the following order of bound cation toxicity: H < Al < (Cu Zn Pb UO2 ) < (Cd Ag). Another trend is a strong increase in Cd toxicity relative to that of Zn as organism complexity increases (from bacteria to fish). PMID:25318827

  20. Timing of porphyry (Cu-Mo) and base metal (Zn-Pb-Ag-Cu) mineralisation in a magmatic-hydrothermal system—Morococha district, Peru

    NASA Astrophysics Data System (ADS)

    Catchpole, Honza; Kouzmanov, Kalin; Bendezú, Aldo; Ovtcharova, Maria; Spikings, Richard; Stein, Holly; Fontboté, Lluís

    2015-12-01

    The Morococha district in central Peru is characterised by economically important Cordilleran polymetallic (Zn-Pb-Ag-Cu) vein and replacement bodies and the large Toromocho porphyry Cu-Mo deposit in its centre. U-Pb, Re-Os, and 40Ar/39Ar geochronology data for various porphyry-related hydrothermal mineralisation styles record a 3.5-Ma multi-stage history of magmatic-hydrothermal activity in the district. In the late Miocene, three individual magmatic-hydrothermal centres were active: the Codiciada, Toromocho, and Ticlio centres, each separated in time and space. The Codiciada centre is the oldest magmatic-hydrothermal system in the district and consists of a composite porphyry stock associated with anhydrous skarn and quartz-molybdenite veins. The hydrothermal events are recorded by a titanite U-Pb age at 9.3 ± 0.2 Ma and a molybdenite Re-Os age at 9.26 ± 0.03 Ma. These ages are indistinguishable from zircon U-Pb ages for porphyry intrusions of the composite stock and indicate a time span of 0.2 Ma for magmatic-hydrothermal activity. The small Ticlio magmatic-hydrothermal centre in the west of the district has a maximum duration of 0.3 Ma, ranging from porphyry emplacement to porphyry mineralisation at 8.04 ± 0.14 Ma (40Ar/39Ar muscovite cooling age). The Toromocho magmatic-hydrothermal centre has a minimum of five recorded porphyry intrusions that span a total of 1.3 Ma and is responsible for the formation of the giant Toromocho Cu-Mo deposit. At least two hydrothermal pulses are identified. Post-dating a first pulse of molybdenite mineralisation, wide-spread hydrous skarn covers an area of over 6 km2 and is recorded by five 40Ar/39Ar cooling ages at 7.2-6.8 Ma. These ages mark the end of the slowly cooling and long-lived Toromocho magmatic-hydrothermal centre soon after last magmatic activity at 7.26 ± 0.02 Ma. District-wide (50 km2) Cordilleran base metal vein and replacement bodies post-date the youngest recorded porphyry mineralisation event at Toromocho

  1. Distributions of dissolved trace metals (Cd, Cu, Mn, Pb, Ag) in the southeastern Atlantic and the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Boye, M.; Wake, B. D.; Lopez Garcia, P.; Bown, J.; Baker, A. R.; Achterberg, E. P.

    2012-08-01

    Comprehensive synoptic datasets (surface water down to 4000 m) of dissolved cadmium (Cd), copper (Cu), manganese (Mn), lead (Pb) and silver (Ag) are presented along a section between 34° S and 57° S in the southeastern Atlantic Ocean and the Southern Ocean to the south off South Africa. The vertical distributions of Cu and Ag display nutrient-like profiles similar to silicic acid, and of Cd similar to phosphate. The distribution of Mn shows a subsurface maximum in the oxygen minimum zone, whereas Pb concentrations are rather invariable with depth. Dry deposition of aerosols is thought to be an important source of Pb to surface waters close to South Africa, and dry deposition and snowfall may have been significant sources of Cu and Mn at the higher latitudes. Furthermore, the advection of water masses enriched in trace metals following contact with continental margins appeared to be an important source of trace elements to the surface, intermediate and deep waters in the southeastern Atlantic Ocean and the Antarctic Circumpolar Current. Hydrothermal inputs may have formed a source of trace metals to the deep waters over the Bouvet Triple Junction ridge crest, as suggested by relatively enhanced dissolved Mn concentrations. The biological utilization of Cu and Ag was proportional to that of silicic acid across the section, suggesting that diatoms formed an important control over the removal of Cu and Ag from surface waters. However, uptake by dino- and nano-flagellates may have influenced the distribution of Cu and Ag in the surface waters of the subtropical Atlantic domain. Cadmium correlated strongly with phosphate (P), yielding lower Cd / P ratios in the subtropical surface waters where phosphate concentrations were below 0.95 μM. The greater depletion of Cd relative to P observed in the Weddell Gyre compared to the Antarctic Circumpolar Current could be due to increase Cd uptake induced by iron-limiting conditions in these high-nutrient-low-chlorophyll waters

  2. Distributions of dissolved trace metals (Cd, Cu, Mn, Pb, Ag) in the southeastern Atlantic and the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Boye, M.; Wake, B. D.; Lopez Garcia, P.; Bown, J.; Baker, A. R.; Achterberg, E. P.

    2012-03-01

    Comprehensive synoptic datasets (surface water down to 4000 m) of dissolved cadmium (Cd), copper (Cu), manganese (Mn), lead (Pb) and silver (Ag) are presented along a section between 34° S and 57° S in the southeastern Atlantic Ocean and the Southern Ocean to the south off South Africa. The vertical distributions of Cu, Ag, and of Cd display nutrient-like profiles similar to silicic acid, and phosphate, respectively. The distribution of Mn shows a subsurface maximum in the oxygen minimum zone, whereas Pb concentrations are rather invariable with depth. Dry deposition of aerosols is thought to be an important source of Pb to surface waters close to South Africa, and dry deposition and snowfall may have been significant sources of Cu and Mn at the higher latitudes. Furthermore, the advection of water-masses enriched in trace metals following contact with continental margins appeared to be an important source of trace elements to the surface, intermediate and deep waters in the southeastern Atlantic Ocean and the Antarctic Circumpolar Current. Hydrothermal inputs appeared to have formed a source of trace metals to the deep waters over the Bouvet Triple Junction ridge crest, as suggested by relatively enhanced dissolved Mn concentrations. The biological utilization of Cu and Ag was proportional to that of silicic acid across the section, suggesting that diatoms formed an important control over the removal of Cu and Ag from surface waters. However uptake by dino- and nano-flagelattes may have influenced the distribution of Cu and Ag in the surface waters of the subtropical Atlantic domain. Cadmium correlated strongly with phosphate (P), yielding lower Cd/P ratios in the subtropical surface waters where phosphate concentrations were below 0.95 μM. The greater depletion of Cd relative to P observed in the Weddell Gyre compared to the Antarctic Circumpolar Current could be due to increase Cd-uptake induced by iron-limiting conditions in these High-Nutrient Low

  3. Crystallographic Study of Mixture CeBa1.8Pb0.2Cu3Oy in the Range of 860 deg. C to 940 deg. C

    SciTech Connect

    Stergiou, A.; Yilmaz, S.; Stergiou, C.

    2007-04-23

    A powder mixture with chemical formula CeBa1.8Pb0.2Cu3Oy was prepared. The mixture was heated in free atmosphere, at temperatures 860 deg. C to 940 deg. C, for 24 to 72h. The samples were measured by X-Ray powder diffraction with CuKa radiation. Each sample was characterized with the help of the PDF and refined, using the Rietveld's ''Powder Profile Analysis''. The first sample (860 deg. C) was identified with the phases: Ba2CeBiO6, CuO and BaCuO2, while all the remaining samples (870 deg. C-940 deg. C) with the phases Ba2CePbO6, CuO and CeO2. The phases Ba2CeBiO6 and Ba2CePbO6 are the main phases with analogous chemical types, but different symmetry. The phase CuO is common in all the samples, while from the remaining phases the BaCuO2 appears only in the first sample and the CeO2 in all, except the first one. The quantity 0.2 of Pb is distributed in the Ba positions, substituting a part of these. The percentages of phases are about 82%, 10% and 8% for the first sample and for all the remaining about 85%, 8% and 7%, respectively with above serious.

  4. Effects of Pb doping on structural and electronic properties of Bi2Sr2Ca2Cu3O10

    NASA Astrophysics Data System (ADS)

    Camargo-Martínez, J. A.; Baquero, R.

    2016-02-01

    Pb doping effect in the Bi2Sr2Ca2Cu3O10 compound (Bi2223) on the structural and electronic properties were investigated, using the Local Density (LDA) and Virtual Crystal (VCA) approximations within the framework of the Density Functional Theory (DFT), taking as reference the procedure implemented by Lin et al. (2006) in the Bi2212 compound. Results show that, the incorporation of Pb-dopant in Bi2223 lead a rigid displacement of the Bi/Pb-O bands toward higher energies, with a null contribution at the Fermi level, around the high symmetry point M bar in the irreducible Brillouin zone, for Pb doping concentration equal to or more than 26%, avoiding the presence of the so-called Bi-O pockets in the Fermi surface, in good agreement with angle-resolved photoemission spectroscopy (ARPES) and nuclear magnetic resonance (NMR) experiments, although a slight metallic character of the Bi-O bonds is still observed which would disagree with some experimental reports. The calculations show that the changes on the structural properties are associated to the presence or absence of the Bi-O pockets in the Fermi surface.

  5. A survey of Pb, Cu, Zn, Cd, Cr, As, and Se in earthworms and soil from diverse sites

    USGS Publications Warehouse

    Beyer, W.N.; Cromartie, E.J.

    1987-01-01

    Earthworms and soils were collected from 20 diverse sites in Maryland, Pennsylvania, and Virginia, and were analyzed for Pb, Cu, Zn, Cd, Cr, As, and Se. Correlation coefficients relating Iconcentrations of the elements in earthworms to concentrations in soil were low (-0.20Pb (2100 ppm), Zn (1600 ppm), Cd (23 ppm) and Se (7.6 ppm) detected in earthworms were in the range reported to be toxic to animals fed diets containing these elements; however, even in the absence of any environmental contamination, some species of earthworms may contain high concentrations of Pb, Zn, and Se. Earthworms of the genus Eisenoides, for example, were exceptional in their ability to concentrate Pb. When earthworms are used as indicators of environmental contamination, it is important to identify the species, to report the soil characteristics, and to collect similar earthworms from very similar but uncontaminated soil.

  6. Thermoelectric transport properties of nanostructured FeSb 2 and Ce-based heavy-fermions CeCu and CeAl 3

    NASA Astrophysics Data System (ADS)

    Pokharel, Mani R.

    Thermoelectric (TE) energy conversion is an all-solid-state technology which can convert waste thermal energy into useful electric power and cool ambience without using harmful gases like CFC. Due to their several advantages over traditional energy conversion technologies, thermoelectric generators (TEG) and coolers (TEC) have drawn enormous research efforts. The objective of this work is to find promising materials for thermoelectric cooling applications and optimize their thermoelectric performances. Finding a material with a good value for the thermoelectric figure-of-merit (ZT) at cryogenic temperatures, specifically below 77 K, has been of great interest. This work demonstrates that FeSb2 1, CeCu6 2 and CeAl3 3, all belonging to a class of materials with strongly correlated electron behavior; exhibit promising thermoelectric properties below 77 K. In general, ZT of a TE material can be increased using two basic approaches: lattice thermal conductivity reduction and power factor (PF) enhancement. The results of this study indicate that nanostructuring effectively decreases the thermal conductivity of FeSb2, CeCu6 and CeAl 3 leading to improved ZT. The approach of introducing point-defect scattering to further reduce the thermal conductivity is successfully implemented for Te-substituted FeSb2 nanostructured samples 4. A semiconductor/metal interface has long been proposed to exhibit enhanced thermoelectric properties. We use this technique by introducing Ag-nanoparticles in the host FeSb2 which further increases ZT by 70% 5. Additionally, a detailed investigation is made on the phonon-drag effect as a possible mechanism responsible for the large value of the Seebeck coefficient of FeSb2 6. We show that the phonon-drag mechanism contributes significantly to the large Seebeck effect in FeSb2 and hence this effect cannot be minor as was proposed in literatures previously. A model based on Kapitza-resistance and effective medium approach (EMA) is used to analyze

  7. Ore geology and fluid inclusion geochemistry of the Tiemurt Pb-Zn-Cu deposit, Altay, Xinjiang, China: A case study of orogenic-type Pb-Zn systems

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Zheng, Yi; Chen, YanJing

    2012-04-01

    The Tiemurt Pb-Zn-Cu deposit is hosted in a Devonian volcanic-sedimentary basin of the Altay orogenic belt, and is thus interpreted to have formed by sea-floor hydrothermal exhalation in previous studies. Our investigation discovered that the deposit is not stratiform or stratabound, but structure-controlled instead. The hydrothermal ore-forming process can be divided into the early, middle and late stage, represented by pyrite-quartz, polymetallic sulfide-quartz and carbonate-quartz veinlets, respectively. The early-stage veins and contained minerals are structurally deformed and brecciated, suggesting a compressional or transpressional tectonic regime. The middle-stage veinlets intrude and infill the fissures of the early-stage assemblages, and show no deformation, suggesting a tensional shear setting. The late-stage veinlets mostly infill open-space fissures that crosscut veins and replacements formed in the earlier stages. Four types of fluid inclusions (FIs), including aqueous (type W), carbonic-aqueous (type C), pure carbonic (type PC) and solid-bearing (type S), are identified at the Tiemurt deposit. The early-stage minerals contain the C- and W-type primary FIs that are totally homogenized at temperatures of 330-390 °C with low salinities of 0.8-11.9 wt.% NaCl eqv.; whilst the late-stage quartz or calcite contains only the W-type FIs with homogenization temperatures of 118-205 °C, and salinities of 1.4-3.4 wt.% NaCl eqv. This indicates that the ore fluid system evolved from CO2-rich, probably metamorphic to CO2-poor, meteoric fluids; and that a significant CO2-escape must have occurred. All the four types of FIs can be only observed in the middle-stage minerals, and even in a microscopic domain of a crystal, representing an association trapped from a boiling fluid system. These FIs homogenize at temperatures ranging from 270 to 330 °C, with two salinity clusters of 1.9-14.5 and 37.4-42.4 wt.% NaCl eqv., respectively. This implies that metal precipitation

  8. Ternary CaCu{sub 4}P{sub 2}-type pnictides AAg{sub 4}Pn{sub 2} (A=Sr, Eu; Pn=As, Sb)

    SciTech Connect

    Stoyko, Stanislav S.; Khatun, Mansura; Scott Mullen, C.; Mar, Arthur

    2012-08-15

    Four ternary pnictides AAg{sub 4}Pn{sub 2} (A=Sr, Eu; Pn=As, Sb) were prepared by reactions of the elements at 850 Degree-Sign C and their crystal structures were determined from single-crystal X-ray diffraction studies. These silver-containing pnictides AAg{sub 4}Pn{sub 2} adopt the trigonal CaCu{sub 4}P{sub 2}-type structure (Pearson symbol hR21, space group R3-bar m, Z=3; a=4.5555(6) A, c=24.041(3) A for SrAg{sub 4}As{sub 2}; a=4.5352(2) A, c=23.7221(11) A for EuAg{sub 4}As{sub 2}; a=4.7404(4) A, c=25.029(2) A for SrAg{sub 4}Sb{sub 2}; a=4.7239(3) A, c=24.689(2) A for EuAg{sub 4}Sb{sub 2}), which can be derived from the trigonal CaAl{sub 2}Si{sub 2}-type structure of the isoelectronic zinc-containing pnictides AZn{sub 2}Pn{sub 2} by insertion of additional Ag atoms into trigonal planar sites within [M{sub 2}Pn{sub 2}]{sup 2-} slabs built up of edge-sharing tetrahedra. Band structure calculations on SrAg{sub 4}As{sub 2} and SrAg{sub 4}Sb{sub 2} revealed that these charge-balanced Zintl phases actually exhibit no gap at the Fermi level and are predicted to be semimetals. - Graphical abstract: SrAg{sub 4}As{sub 2} and related pnictides adopt a CaCu{sub 4}P{sub 2}-type structure in which additional Ag atoms enter trigonal planar sites within slabs built from edge-sharing tetrahedra. Highlights: Black-Right-Pointing-Pointer AAg{sub 4}Pn{sub 2} are the first Ag-containing members of the CaCu{sub 4}P{sub 2}-type structure. Black-Right-Pointing-Pointer Ag atoms are stuffed in trigonal planar sites within CaAl{sub 2}Si{sub 2}-type slabs. Black-Right-Pointing-Pointer Ag-Ag bonding develops through attractive d{sup 10}-d{sup 10} interactions.

  9. Synthesis, crystal structure and magnetic properties of a new copper oxo-antimony sulphate CuSb6O8(SO4)2.

    PubMed

    Zimmermann, Iwan; Kremer, Reinhard K; Hu, Shichao; Johnsson, Mats

    2016-01-01

    The new copper oxo-antimony sulphate CuSb6O8(SO4)2 crystallizes in the triclinic space group P1[combining macron] with the unit cell parameters a = 5.5342(4) Å, b = 7.6706(6) Å, c = 9.2374(7) Å, α = 96.505(5)°, β = 93.818(4)°, γ = 109.733(4)° and Z = 1. The crystal structure is made up of layers stacking along [001]. The layers are charge neutral and are connected to each other by only weak interactions. The copper atoms adopt a square planar [CuO4] coordination and such units are well separated from each other by corner and edge sharing to [SbO4] building blocks. The latter polymerize to form sheets with the formula [Sb3O8]∞. Sulphate groups connect to the antimony oxide sheets by corner sharing and are located at the interface of the layers. Above ∼10 K the magnetic susceptibility follows very well a Curie-Weiss law whereas below 10 K increasing deviations indicate the onset of antiferromagnetic correlations. Fitting the data in the range 10-50 K yields a Curie-Weiss temperature θ of -2.25(5) K. A sharp anomaly centered at TC = 0.67 K in the heat capacity data indicates long-range magnetic ordering. Short range antiferromagnetic correlations well above TC are seen in the magnetic contribution to the heat capacity and the magnetic susceptibility. These can be well described by the magnetism of a spin S = 1/2 Heisenberg chain with the nearest neighbor antiferromagnetic spin exchange interaction of Jintra = ∼2.8 K. PMID:26619936

  10. Directional solidification of Cu- Pb and Bi- Ga monotectic alloys under normal gravity and during parabolic flight

    NASA Astrophysics Data System (ADS)

    Dhindaw, B. K.; Stefanescu, D. M.; Singh, A. K.; Curreri, P. A.

    1988-11-01

    Cu-Pb and Bi-Ga monotectic alloys of nominal hypermonotectic compositions were directionally solidified under various furnace translation rates, temperature gradients, and gravity levels. Gravity was varied by solidifying the alloys under ground conditions and in the furnace aboard NASA KC-135 aircraft, flying on parabolic trajectories. High translation rates, high gradients, high gravity levels, and higher density and lower thermal conductivity of the L2 phase favored the formation of fiber composite structure, while the opposite conditions resulted in structures consisting of L2 droplets in α matrix. A modified particle engulfment theory as originally enunciated by Ulhmann et al. is proposed to explain these observations.

  11. Directional solidification of Cu-Pb and Bi-Ga monotectic alloys under normal gravity and during parabolic flight

    NASA Technical Reports Server (NTRS)

    Dhindaw, B. K.; Stefanescu, D. M.; Singh, A. K.; Curreri, P. A.

    1988-01-01

    Cu-Pb and Bi-Ga monotectic alloys of nominal hypermonotectic compositions were directionally solidified under various furnace translation rates, temperature gradients, and gravity levels. Gravity was varied by solidifying the alloys under ground conditions and in the furnace aboard NASA KC-135 aircraft, flying on parabolic trajectories. High translation rates, high gradients, high gravity levels, and higher density and lower thermal conductivity of the L2 phase favored the formation of fiber composite structure, while the opposite conditions resulted in structures consisting of L2 droplets in alpha matrix. A modified particle engulfment theory as originally enunciated by Ulhmann et al. (1964) is proposed to explain these observations.

  12. Properties of Bi(Pb)-Sr-Ca-Cu-O superconducting tapes prepared by the doctor-blade process

    SciTech Connect

    Yanagisawa, E.; Morimoto, T.; Dietderich, D. R.; Kumakura, H.; Togano, K.; Maeda, H.

    1989-06-19

    Improved superconducting and mechanical properties were obtained forBi(Pb)-Sr-Ca-Cu-O tapes, prepared by the combined process of doctor-bladecasting, cold rolling, and sintering. The tape has an oriented microstructurewith the high /ital T//sub /ital c// plate-like grains having their /ital c/ axesperpendicular to the rolling surface. The tape is flexible and can be bentwithout any degradation of /ital J//sub /ital c// to just before fracture (strainlarger than /similar to/0.12%).

  13. Bioacumulation and ultrastructural effects of Cd, Cu, Pb and Zn in the moss Scorpiurum circinatum (Brid.) Fleisch. & Loeske.

    PubMed

    Basile, A; Sorbo, S; Pisani, T; Paoli, L; Munzi, S; Loppi, S

    2012-07-01

    This paper tested if culturing the moss Scorpiurum circinatum (Brid.) Fleisch. & Loeske with metal solutions (Cd, Cu, Pb and Zn) for 30 days causes metal bioaccumulation and ultrastructural changes. The results showed that despite the high heavy metal concentrations in treatment solutions, treated samples did not show severe ultrastructural changes and cells were still alive and generally well preserved. Bioaccumulation highlighted that moss cells survived to heavy metal toxicity by immobilizing most toxic ions extracellularly, likely in binding sites of the cell wall, which is the main site of metal detoxification. PMID:22516710

  14. Inherent room temperature ferromagnetism and dopant dependent Raman studies of PbSe, Pb{sub 1−x}Cu{sub x}Se, and Pb{sub 1−x}Ni{sub x}Se

    SciTech Connect

    Gayner, Chhatrasal; Kar, Kamal K.

    2015-03-14

    Polycrystalline lead selenide (PbSe) doped with copper (Cu) and nickel (Ni) was prepared to understand its magnetic behaviour and Raman activity. The processing conditions, influence of dopants (magnetically active and non-active) and their respective compositions on the magnetic properties and Raman active mode were studied. A surprising/anomalous room temperature ferromagnetism (hysteresis loop) is noticed in bulk diamagnetic PbSe, which is found to be natural or inherent characteristic of material, and depends on the crystallite size, dopant, and developed strain due to dopant/defects. The magnetic susceptibility (−1.71 × 10{sup −4} emu/mol Oe) and saturated magnetic susceptibility (−2.74 × 10{sup −4} emu/mol Oe) are found to be higher than the earlier reported value (diamagnetic: −1.0 × 10{sup −4} emu/mol Oe) in bulk PbSe. With increase of Cu concentration (2% to 10%) in PbSe, the saturated magnetic susceptibility decreases from −1.22 × 10{sup −4} to −0.85 × 10{sup −4} emu/mol Oe. Whereas for Ni dopant, the saturated magnetic susceptibility increases to −2.96 × 10{sup −4} emu/mol Oe at 2% Ni doped PbSe. But it further decreases with dopant concentration. In these doped PbSe, the shifting of longitudinal (LO) phonon mode was also studied by the Raman spectroscopy. The shifting of LO mode is found to be dopant dependent, and the frequency shift of LO mode is associated with the induced strain that created by the dopants and vacancies. This asymmetry in LO phonon mode (peak shift and shape) may be due to the intraband electronic transition of dopants. The variation in magnetic susceptibility and Raman shifts are sensitive to crystallite size, nature of dopant, concentration of dopants, and induced strain due to dopants.

  15. Anthropogenic impacts in North Poland over the last 1300 years--a record of Pb, Zn, Cu, Ni and S in an ombrotrophic peat bog.

    PubMed

    De Vleeschouwer, François; Fagel, Nathalie; Cheburkin, Andriy; Pazdur, Anna; Sikorski, Jaroslaw; Mattielli, Nadine; Renson, Virginie; Fialkiewicz, Barbara; Piotrowska, Natalia; Le Roux, Gaël

    2009-10-15

    Lead pollution history over Northern Poland was reconstructed for the last ca. 1300 years using the elemental and Pb isotope geochemistry of a dated Polish peat bog. The data show that Polish Pb-Zn ores and coal were the main sources of Pb, other heavy metals and S over Northern Poland up until the industrial revolution. After review of the potential mobility of each element, most of the historical interpretation was based on Pb and Pb isotopes, the other chemical elements (Zn, Cu, Ni, S) being considered secondary indicators of pollution. During the last century, leaded gasoline also contributed to anthropogenic Pb pollution over Poland. Coal and Pb-Zn ores, however, remained important sources of pollution in Eastern European countries during the last 50 years, as demonstrated by a high (206)Pb/(207)Pb ratio (1.153) relative to that of Western Europe (ca. 1.10). The Pb data for the last century were also in good agreement with modelled Pb inventories over Poland and the Baltic region. PMID:19683332

  16. Electronic transitions of Ho in Pb2Sr2HoCu3O8 observed by inelastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Soderholm, L.; Loong, C.-K.; Xue, J. S.; Hammonds, J. P.; Greedan, J. E.; Maric, M.

    1993-05-01

    The electronic behavior of the 5I8 Russell Saunders ground multiplet of Ho3+ in Pb2Sr2HoCu3O8 has been investigated using inelastic neutron scattering. We observe ten peaks in the excitation spectra that are associated with crystal field transitions. The peaks are only slightly broader than expected from instrument resolution, indicating that there are no strong interactions between the local Ho f states and the CuO conduction states. Comparing the energies and intensities of the experimental peaks with those expected from modeling convinces us that there are at least three states populated at the temperature of our experiment (15 K), making the assignments of transitions very difficult in the absence of further data.

  17. Comparison of Cd(II), Cu(II), and Pb(II) biouptake by green algae in the presence of humic acid.

    PubMed

    Lamelas, Cristina; Slaveykova, Vera I

    2007-06-01

    The present study examines the role of humic acid, as a representative of dissolved organic matter, in Cd(II), Cu(II), and Pb(II) speciation and biouptake by green microalgae. Cellular and intracellular metal fractions were compared in the presence of citric and humic acids. The results demonstrated that Cd and Cu uptake in the presence of 10 mg L(-1) humic acid was consistent with that predicted from measured free metal concentrations, while Pb biouptake was higher. By comparing Cd, Cu, and Pb cellular concentrations in the absence and presence of humic acid, it was found that the influence of the increased negative algal surface charge, resulting from humic acid adsorption, on cellular metal was negligible. Moreover, the experimental results for all three metals were in good agreement with the ternary complex hypothesis. Given that metal has much higher affinity with algal sites than humic acid adsorbed to algae, the contribution of the ternary complex to metal bioavailability was negligible in the case of Cd (II) and Cu (II). In contrast, the ternary complex contributed to over 90% of total cellular metal for Pb(II), due to the comparable affinity of Pb to algal sites in comparison with humic acid adsorbed to algae. Therefore, the extension of the biotic ligand model by including the formation of the ternary complex between the metal, humic acid, and algal surface would help to avoid underestimation of Pb biouptake in the presence of humic substances by green algae Chlorella kesslerii. PMID:17612207

  18. Removal of Pb(II) and Cu(II) from aqueous solution using multiwalled carbon nanotubes/iron oxide magnetic composites.

    PubMed

    Hu, Jun; Zhao, Donglin; Wang, Xiangke

    2011-01-01

    Multiwalled carbon nanotubes (MWCNTs)/iron oxide magnetic composites (named as MCs) were prepared by co-precipitation method, and were characterised by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) in detail. The prepared MCs were employed as an adsorbent for the removal of Pb(II) and Cu(II) ions from wastewater in heavy metal ion pollution cleanup. The results demonstrated that the sorption of Pb(II) and Cu(II) ions was strongly dependent on pH and temperature. The experimental data were well described by Langmuir model, and the monolayer sorption capacity of MCs was found to vary from 10.02 to 31.25 mg/g for Pb(II) and from 3.11 to 8.92 mg/g for Cu(II) at temperature increasing from 293.15 to 353.15 K at pH 5.50. The sorption capacity of Pb(II) on MCs was higher than that of Cu(II), which was attributed to their ionic radius, hydration energies and hydrolysis of their hydroxides. The thermodynamic parameters (i.e., ΔH(0), ΔS(0) and ΔG(0)) were calculated from temperature dependent sorption isotherms, and the results indicated that the sorption of Pb(II) and Cu(II) ions on MCs were spontaneous and endothermic processes. PMID:21411941

  19. In situ electrokinetic remediation of As-, Cu-, and Pb-contaminated paddy soil using hexagonal electrode configuration: a full scale study.

    PubMed

    Jeon, Eun-Ki; Jung, Ji-Min; Kim, Woo-Seung; Ko, Sung-Hwan; Baek, Kitae

    2015-01-01

    We investigated the in situ applicability of the electrokinetic process with a hexagonal electrode configuration in order to remediate arsenic (As)-, copper (Cu)-, and lead (Pb)-contaminated paddy rice field soil at a field scale (width 17 m, length 12.2 m, and depth 1.6 m). An iron electrode was used in order to prevent the severe acidification of the soil near the anode. We selected ethylenediaminetetraacetic acid (EDTA) as a pursing electrolyte to enhance the extraction of Cu and Pb. The system removed 44.4% of the As, 40.3% of the Cu, and 46.6% of the Pb after 24 weeks of operation. Fractionation analysis showed that the As bound to amorphous ion (Fe) and aluminum (Al) oxyhydroxides was changed into a form of As specifically bound. In the case of Cu and Pb, the fraction bound to Fe-Mn oxyhydroxide primarily decreased. The EDTA formed negatively charged complexes with Cu and Pb, and those complexes were transported toward the anode. The energy consumption was very low compared to that on a small scale because there was less energy consumption due to Joule heating. These results show that the in situ electrokinetic process could be applied in order to remediate paddy rice fields contaminated with multiple metals. PMID:25103944

  20. Toxicities and tolerances of Cd, Cu, Pb and Zn in a primary producer (Isochrysis galbana) and in a primary consumer (Perna viridis).

    PubMed

    Yap, C K; Ismail, A; Omar, H; Tan, S G

    2004-02-01

    Studies on toxicities and tolerances of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in the brown alga Isochrysis galbana and in the green-lipped mussel Perna viridis were conducted by short-term bioassays using endpoints growth production and mortality, respectively. The 5-day EC(50) and 24-h LC(50) of these heavy metals were determined in the brown alga and mussel, respectively. The EC(50) values calculated for the alga were 0.74 mg/l for Cd, 0.91 mg/l for Cu, 1.40 mg/l for Pb and 0.60 mg/l for Zn. The LC(50) values for the mussels were 1.53 mg/l for Cd, 0.25 mg/l for Cu, 4.12 mg/l for Pb and 3.20 mg/l for Zn. These LC(50) values were within the concentration ranges as reported by other authors who used P. viridis as the test organism. Based on these EC(50) and LC(50) values, the alga was most sensitive to Zn, followed by Cd, Cu and Pb while the mussel was most sensitive to Cu, followed by Cd, Zn and Pb. Differences in the trophic levels, metal handling strategies, biology and ecology of the primary producer (brown alga) and the primary consumer (mussel) are believed to be the plausible causes for the different toxicities and tolerances of the metals studied. PMID:14680893

  1. Comparative toxicity of lead (Pb2+), copper (Cu2+), and mixtures of lead and copper to zebrafish embryos on a microfluidic chip

    PubMed Central

    Li, Yinbao; Yang, Xiujuan; Zhang, Beibei; Pan, Jianbin; Li, Xinchun; Yang, Fan; Sun, Duanping

    2015-01-01

    Investigations were conducted to determine acute effects of Pb2+ and Cu2+ presented individually and collectively on zebrafish embryos. Aquatic safety testing requires a cheap, fast, and highly efficient platform for real-time evaluation of single and mixture of metal toxicity. In this study, we have developed a microfluidic system for phenotype-based evaluation of toxic effects of Pb2+ and Cu2+ using zebrafish (Danio rerio) embryos. The microfluidic chip is composed of a disc-shaped concentration gradient generator and 24 culture chambers, which can generate one blank solution, seven mixture concentrations, and eight single concentrations for each metal solution, thus enabling the assessment of zebrafish embryos. To test the accuracy of this new chip platform, we have examined the toxicity and teratogenicity of Pb2+ and Cu2+ on embryos. The individual and combined impact of Pb2+ and Cu2+ on zebrafish embryonic development was quantitatively assessed by recording a series of physiological indicators, such as spontaneous motion at 22 hours post fertilization (hpf), mortality at 24 hpf, heartbeat and body length at 96 hpf, etc. It was found that Pb2+ or Cu2+ could induce deformity and cardiovascular toxicity in zebrafish embryos and the mixture could induce more severe toxicity. This chip is a multiplexed testing apparatus that allows for the examination of toxicity and teratogenicity for substances and it also can be used as a potentially cost-effective and rapid aquatic safety assessment tool. PMID:25825620

  2. Competitive sorption of Pb(II), Cu(II) and Ni(II) on carbonaceous nanofibers: A spectroscopic and modeling approach.

    PubMed

    Ding, Congcong; Cheng, Wencai; Wang, Xiangxue; Wu, Zhen-Yu; Sun, Yubing; Chen, Changlun; Wang, Xiangke; Yu, Shu-Hong

    2016-08-01

    The competitive sorption of Pb(II), Cu(II) and Ni(II) on the uniform carbonaceous nanofibers (CNFs) was investigated in binary/ternary-metal systems. The pH-dependent sorption of Pb(II), Cu(II) and Ni(II) on CNFs was independent of ionic strength, indicating that inner-sphere surface complexation dominated sorption Pb(II), Cu(II) and Ni(II) on CNFs. The maximum sorption capacities of Pb(II), Cu(II) and Ni(II) on CNFs in single-metal systems at a pH 5.5±0.2 and 25±1°C were 3.84 (795.65mg/g), 3.21 (204.00mg/g) and 2.67 (156.70mg/g)mmol/g, respectively. In equimolar binary/ternary-metal systems, Pb(II) exhibited greater inhibition of the sorption of Cu(II) and Ni(II), demonstrating the stronger affinity of CNFs for Pb(II). The competitive sorption of heavy metals in ternary-metal systems was predicted quite well by surface complexation modeling derived from single-metal data. According to FTIR, XPS and EXAFS analyses, Pb(II), Cu(II) and Ni(II) were specifically adsorbed on CNFs via covalent bonding. These observations should provide an essential start in simultaneous removal of multiple heavy metals from aquatic environments by CNFs, and open the doorways for the application of CNFs. PMID:27108273

  3. Mobility of Pb, Cu, and Zn in the phosphorus-amended contaminated soils under simulated landfill and rainfall conditions.

    PubMed

    Cao, Xinde; Liang, Yuan; Zhao, Ling; Le, Huangying

    2013-09-01

    Phosphorus-bearing materials have been widely applied in immobilization of heavy metals in contaminated soils. However, the study on the stability of the initially P-induced immobilized metals in the contaminated soils is far limited. This work was conducted to evaluate the mobility of Pb, Cu, and Zn in two contrasting contaminated soils amended with phosphate rock tailing (PR) and triple superphosphate fertilizer (TSP), and their combination (P + T) under simulated landfill and rainfall conditions. The main objective was to determine the stability of heavy metals in the P-treated contaminated soils in response to the changing environment conditions. The soils were amended with the P-bearing materials at a 2:1 molar ratio of P to metals. After equilibrated for 2 weeks, the soils were evaluated with the leaching procedures. The batch-based toxicity characteristic leaching procedure (TCLP) was conducted to determine the leachability of heavy metals from both untreated and P-treated soils under simulated landfill condition. The column-based synthetic precipitation leaching procedure (SPLP) were undertaken to measure the downward migration of metals from untreated and P-treated soils under simulated rainfall condition. Leachability of Pb, Cu, and Zn in the TCLP extract followed the order of Zn > Cu > Pb in both soils, with the organic-C- and clay-poor soil showing higher metal leachability than the organic-C- and clay-rich soil. All three P treatments reduced leachability of Pb, Cu, and Zn by up to 89.2, 24.4, and 34.3 %, respectively, compared to the untreated soil, and TSP revealed more effectiveness followed by P + T and then PR. The column experiments showed that Zn had the highest downward migration upon 10 pore volumes of SPLP leaching, followed by Pb and then Cu in both soils. However, migration of Pb and Zn to subsoil and leachate were inhibited in the P-treated soil, while Cu in the leachate was enhanced by P treatment in the organic

  4. Metallogeny of precious and base metal mineralization in the Murchison Greenstone Belt, South Africa: indications from U-Pb and Pb-Pb geochronology

    NASA Astrophysics Data System (ADS)

    Jaguin, J.; Poujol, M.; Boulvais, P.; Robb, L. J.; Paquette, J. L.

    2012-10-01

    The 3.09 to 2.97 Ga Murchison Greenstone Belt is an important metallotect in the northern Kaapvaal Craton (South Africa), hosting several precious and base metal deposits. Central to the metallotect is the Antimony Line, striking ENE for over 35 km, which hosts a series of structurally controlled Sb-Au deposits. To the north of the Antimony Line, hosted within felsic volcanic rocks, is the Copper-Zinc Line where a series of small, ca. 2.97 Ga Cu-Zn volcanogenic massive sulfide (VMS)-type deposits occur. New data are provided for the Malati Pump gold mine, located at the eastern end of the Antimony Line. Crystallizations of a granodiorite in the Malati Pump Mine and of the Baderoukwe granodiorite are dated at 2,964 ± 7 and 2,970 ± 7 Ma, respectively (zircon U-Pb), while pyrite associated with gold mineralization yielded a Pb-Pb age of 2,967 ± 48 Ma. Therefore, granodiorite emplacement, sulfide mineral deposition and gold mineralization all happened at ca. 2.97 Ga. It is, thus, suggested that the major styles of orogenic Au-Sb and the Cu-Zn VMS mineralization in the Murchison Greenstone Belt are contemporaneous and that the formation of meso- to epithermal Au-Sb mineralization at fairly shallow levels was accompanied by submarine extrusion of felsic volcanic rocks to form associated Cu-Zn VMS mineralization.

  5. Fifty-year sedimentary record of heavy metal pollution (Cd, Zn, Cu, Pb) in the Lot River reservoirs (France).

    PubMed

    Audry, Stéphane; Schäfer, Jörg; Blanc, Gérard; Jouanneau, Jean-Marie

    2004-12-01

    The Lot-Garonne fluvial system is known for its historic heavy metal pollution resulting from mining and smelting activities since the late 19th century. Here, we report 137Cs activities and heavy metal (Cd, Zn, Cu, Pb and V) concentration-depth profiles from sediment cores retrieved in 2001 from three reservoirs in the Lot River. High mean sedimentation rates of 2.4-2.8 cm a(-1) are indicated by 137Cs dating. The reservoir sediments have recorded the heavy metal deposition and thus allow establishing a connection between the temporal evolution of the heavy metal pollution and historical changes in smelting and waste-treatment proceedings. Based on heavy metal concentrations in sediments upstream of the anthropogenic inputs and bottom-sediments of the furthest downstream core (interpreted as old soil or riverbed), concentrations of approximately 17, approximately 82, approximately 0.33 and approximately 28 mg kg(-1) for Cu, Zn, Cd and Pb, respectively, are proposed as natural background values for the Lot fluvial system. The geoaccumulation index (Igeo [Müller, G., 1979. Schwermetalle in den Sedimenten des Rheins-Veränderungen seit. Umschav 79, 133-149.]) revealed that the Lot River sediments must be considered as "severely polluted" in Cd and Zn. Moreover, despite remediation efforts undertaken in the former smelting site, the Lot River is still "severely" (Igeo approximately 4) and "moderately to severely" (Igeo>2) impacted by Cd and Zn inputs, respectively. PMID:15325457

  6. The spatial and temporal trends of Cd, Cu, Hg, Pb and Zn in Seine River floodplain deposits (1994-2000)

    USGS Publications Warehouse

    Grosbois, C.; Meybeck, M.; Horowitz, A.; Ficht, A.

    2006-01-01

    Fresh floodplain deposits (FD), from 11 key stations, covering the Seine mainstem and its major tributaries (Yonne, Marne and Oise Rivers), were sampled from 1994 to 2000. Background levels for Cd, Cu, Hg, Pb, and Zn were established using prehistoric FD and actual bed sediments collected in small forested sub-basins in the most upstream part of the basin. Throughout the Seine River Basin, FD contain elevated concentrations of Cd, Cu, Hg, Pb and Zn compared to local background values (by factors > twofold). In the Seine River Basin, trace element concentrations display substantial downstream increases as a result of increasing population densities, particularly from Greater Paris (10 million inhabitants), and reach their maxima at the river mouth (Poses). These elevated levels make the Seine one of the most heavily impacted rivers in the world. On the other hand, floodplain-associated trace element levels have declined over the past 7 years. This mirrors results from contemporaneous suspended sediment surveys at the river mouth for the 1984-1999 period. Most of these temporal declines appear to reflect reductions in industrial and domestic solid wastes discharged from the main Parisian sewage plant (Seine Aval). ?? 2005 Elsevier B.V. All rights reserved.

  7. Evaluation of Adsorption Capacity of Montmorillonite and Aluminium-pillared Clay for Pb2+, Cu2+ and Zn2.

    PubMed

    Humelnicu, Doina; Ignat, Maria; Suchea, Mirela

    2015-01-01

    Adsorption capacity of the two adsorbents was investigated as a function of contact time between adsorbent and heavy metal ions solutions, the initial heavy metals concentration of the synthetic wastewater, pH value, temperature and adsorbent mass. Preliminary experiments at different pH values between 2.0 and 7.0 were performed, and were observed that maximum adsorption occurs at pH 5 for copper (q(max) = 92.59 mg · g(–1)), 6.0 for lead (qmax = 97.08 mg · g(–1)) and 6.5 for zinc ions (q(max) = 73.52 mg · g(–1)), respectively. The sorption capacity of studied adsorbents for Pb(2+), Cu(2+) and Zn(2+) was calculated using Langmuir and Freundlich models. Thermodynamic parameters – enthalpy change (ΔH(0)), entropychange (ΔS(0)) and free energy (ΔG(0)) – were calculated for predicting the nature of adsorption. Scanning electron micrograph(SEM) revealed changes in the surface morphology of the adsorbent as a result of heavy metal ions adsorption.EDS characterization confirmed qualitatively the presence of adsorbed species in the samples. On the basis of the obtained results the adsorption it was proposed an ordered adsorption: Pb(2+), Cu(2+) and Zn(2+), on the sorbents we investigated. PMID:26680724

  8. Red mud and fly ash for remediation of mine sites contaminated with As, Cd, Cu, Pb and Zn.

    PubMed

    Bertocchi, Anna F; Ghiani, Marcello; Peretti, Roberto; Zucca, Antonio

    2006-06-30

    The paper presents the results of a laboratory investigation conducted for assessing the feasibility of immobilising the heavy metals (As, Cd, Cu, Pb and Zn) contained in a disused mine tailings dam. Samples of tailings were mixed with relatively small proportions of bauxite red mud and power station fly ash. The sorption capacity of these two materials, already determined for Cd, Cu, Pb and Zn, has been determined here for arsenic by means of batch experiments on purposely prepared solutions. The results of this preliminary investigation show that sorption capacity is strongly influenced by pH. While the red mud performs better at low pH, the ability of fly ash to adsorb As increases with increasing pH. Tests carried out in leach columns containing tailings alone and tailings mixed with 15% by weight neutralized red mud or fly ash demonstrate the heavy metal sorption potential of the two materials, the red mud proving to be the more effective. PMID:16326004

  9. Distribution and determination of Pb, Cd, Bi and Cu in the sea brine system: solution--colloidal particles--biota.

    PubMed

    Bozhkov, Ognyan; Tzvetkova, Christina; Russeva, Elena

    2006-01-01

    The distribution of Pb, Cd, Bi, and Cu in Black Sea brine system (solution--colloidal particles--biota) produced in Burgas and Pomorie salterns is studied. The established distribution of the title elements among the brine components is as follows: Pb--25% in the salt solution, 30%--in colloidal particles, 45%--in biota (Halobacterium salinarium and microalgae Dunaliela salina); Cu--30% in the salt solution, 22%--in colloidal particles, 48%--in biota. Cd and Bi are not detected in biota. They are uniformly distributed (50%: 50%) between the salt solution and colloidal particles. Two procedures for analysis are developed. The first one is designed for determination of the total content of the studied metals in brine. It involves elimination of the biota interference by addition of ethanol, extraction and pre-concentration of the metals with NaDDC into CCl4 followed by FAAS determination. The second procedure intends determination of the elements in the separate components of the brine. It involves separation of the colloidal particles through centrifugation, separation of the studied elements from the resulting solution as dithiocarbamate complexes on a Millipore filter, dissolution of the retained metal species and subsequent FAAS analysis. PMID:16948432

  10. Partitioning of Pb, Cd, and Cu in natural and disturbed salt marshes of eastern San Francisco Bay

    SciTech Connect

    Alai, M.; Fegan, N. . Dept. of Geological Sciences)

    1993-04-01

    Sediment from different marsh systems along eastern San Francisco Bay was analyzed to determine how metals are partitioned in different environments influenced by human activity. Human influences in the marshes may have altered the geochemical processes controlling the metal partitioning. The three marsh systems analyzed include a natural marsh (San Francisco Wildlife Refuge), a natural marsh influenced by landfill leachate (Triangle Marsh), and a disturbed marsh constructed of artificial fill (Hayward Landing). The trace metal concentrations were compared in: easily exchangeable, weakly acid soluble, reducible, and oxidizable fractions representing the sediment phases of: clays, carbonates, Mn or Fe oxyhydroxides, and sulfides or organic material, respectively. The sediment fractions were analyzed for Pb, Cd, and Cu. In all three marshes, the pattern of metal partitioning with depth is similar; however, there are some inconsistencies. The Pb, Cd, and Cu in the reducible fraction typically decrease with depth while the metals in the oxidizable fraction generally increase or remain approximately constant with depth. This data suggests that the partitioning of metals in all three environments is initially controlled by sorption of metals onto Mn or Fe oxyhydroxides at the surface and shifts to organic or sulfides as the sediments is buried and the environment becomes more reducing.

  11. Enriching and Separating Primary Copper Impurity from Pb-3 Mass Pct Cu Melt by Super-Gravity Technology

    NASA Astrophysics Data System (ADS)

    Yang, Yuhou; Song, Bo; Song, Gaoyang; Yang, Zhanbing; Xin, Wenbin

    2016-08-01

    In this study, super-gravity technology was introduced in the lead bullion-refining process to investigate the enriching and separating laws of copper impurity from Pb-3 mass pct Cu melt. With the gravity coefficient G = 700 at the cooling rate of ν = 5 K min-1, the entire copper phase gathers at the upper area of the sample, and it is hard to find any copper particles at the bottom area of the sample. The floatation movement of copper phase was greatly intensified by super gravity and the mass pct of copper in tailing lead is up to 8.631 pct, while that in the refined lead is only 0.113 pct. The refining rate of lead bullion reached up to 94.27 pct. Copper-phase impurity can be separated effectively from Pb-3 mass pct Cu melt by filtration method in super-gravity field, and the separation efficiency increased with the increasing gravity coefficient in the range of G ≥ 10. After filtration at 613 K (340 °C) with gravity coefficient G = 100 for 10 minutes, the refined lead, with just 0.157 mass pct copper impurity, was separated to the bottom of the crucible, and the copper dross containing only 23.56 mass pct residual lead was intercepted by the carbon fiber felt, leading to the separation efficiency up to 96.18 pct (meaning a great reduction in metal loss).

  12. Organic acids pretreatment effect on Rosa bourbonia phyto-biomass for removal of Pb(II) and Cu(II) from aqueous media.

    PubMed

    Manzoor, Qaisar; Nadeem, Raziya; Iqbal, Munawar; Saeed, Rashid; Ansari, Tariq M

    2013-03-01

    The sorption of Pb(II) and Cu(II) form aqueous media by Rosa bourbonia waste phyto-biomass (RBWPB) pretreated with organic acids was investigated as a function of biosorbent dosage, initial metal ions concentration and contact time. The equilibrium biosorption data was analyzed using two kinetic models (pseudo-first order and pseudo-second order) and two isotherm models (Langmuir and Freundlich). The RBWPB was successfully applied for sequestration of both heavy metal ions; however, organic acids pretreatments decreased the metal adsorption capacity of RBWPB. The Langmuir model fitted well to the data, and the pseudo-second order kinetic equation could best describe the biosorption kinetics of Pb(II) and Cu(II) metal ions. Gibbs free energy indicated the spontaneous adsorption of Pb(II) and Cu(II) onto RBWPB. PMID:23433975

  13. Reactivity of no-clean pastes and fluxes for the surface mount technology process—part I: Corrosion behavior of Cu, Sn, and Pb

    NASA Astrophysics Data System (ADS)

    Cavallotti, P. L.; Zangari, G.; Sirtori, V.

    1995-04-01

    No-clean fluxes allow simplifications in the surface mount technology process, but introduce reliability problems for electronic assemblies during their service life. An electrochemical method is devised to study the anodic reactivity of Sn, Pb, eutectic Sn-Pb solder alloy and Cu in aqueous solutions containing no-clean paste residues obtained during a reflow process. The potential corrosion risk of residues from two different pastes is evaluated, and the corrosion behavior of the different metals assessed. Cu corrodes faster than Sn, Pb, and the solder alloy in presence of the residues, but corrosion starts at higher overvoltages. Pb corrodes at low overvoltage; Sn is prone to oxidation and passivation. The solder alloy has an intermediate behavior between those of the pure metals.

  14. Epitaxial growth and superconducting anisotropy of PbSr2Y1-xCaxCu2O7+δ thin films

    NASA Astrophysics Data System (ADS)

    Komori, S.; Inaba, R.; Kaneko, K.; Fujita, S.; Kakeya, I.; Suzuki, M.

    2014-05-01

    Thin films of single-crystal Pb1-yBiySr2Y1-xCaxCu2O7+δ (PbBi1212) were grown on SrTiO3 (100) substrates by a two-step growth technique in which an amorphous film is annealed at 970 ∘C in a closed ceramic container prepared using the same material as the film. We find that PbBi1212 exhibits superconductivity when the Ca concentration x exceeds 0.3. The effective number of holes per Cu atom neff is well described as neff=0.34x. The highest onset temperature for the superconducting transition attained in the present study is 65 K. The resistivity measurement in a magnetic field reveals that the coherence lengths of Pb1212 (y =0) are approximately 25 and 2.7 Å along the ab plane and the c axis, respectively.

  15. Complex permeability spectra of PbO and Ta2O5 added nanocrystalline MgCuZn ferrites

    NASA Astrophysics Data System (ADS)

    V, Seetha Rama Raju

    2015-05-01

    PbO and Ta2O5 added MgCuZn ferrites are prepared by the Microwave-Hydrothermal (M-H) processing. The nanocrystalline ferrites are sintered to a temperature of 900 °C/4 h. SEM pictures reveal that, the addition of PbO causes a small amount of grain growth, whereas the addition of Ta2O5 causes a fine-grained microstructure. The complex permeability spectra (μ*=μ‧-iμ″) of the prepared samples were measured in the frequency range from 1 MHz to 1.8 GHz, the μ* spectra are analyzed into two magnetization processes with focus on the particle size of ferrite samples. In addition to the spin rotation relaxation in 130-200 MHz, it is initially identified the contribution from reversible domain wall bowing rising at 6-40 MHz. The magnetic state of the ferrite is also influenced by the addition of PbO and Ta2O5. The spin rotation mechanism of the present ferrites is enhanced by the preparation of nanocrystalline samples.

  16. In situ field application of electrokinetic remediation for an As-, Cu-, and Pb-contaminated rice paddy site using parallel electrode configuration.

    PubMed

    Jeon, Eun-Ki; Jung, Ji-Min; Ryu, So-Ri; Baek, Kitae

    2015-10-01

    The applicability of an in situ electrokinetic process with a parallel electrode configuration was evaluated to treat an As-, Cu-, and Pb-contaminated paddy rice field in full scale (width, 17 m; length, 12.2 m; depth, 1.6 m). A constant voltage of 100 V was supplied and electrodes were spaced 2 m apart. Most As, Cu, and Pb were bound to Fe oxide and the major clay minerals in the test site were kaolinite and muscovite. The electrokinetic system removed 48.7, 48.9, and 54.5 % of As, Cu, and Pb, respectively, from the soil during 24 weeks. The removal of metals in the first layer (0-0.4 m) was higher than that in the other three layers because it was not influenced by groundwater fluctuation. Fractionation analysis showed that As and Pb bound to amorphous Fe and Al oxides decreased mainly, and energy consumption was 1.2 kWh/m(3). The standard deviation of metal concentration in the soil was much higher compared to the hexagonal electrode configuration because of a smaller electrical active area; however, the electrode configuration removed similar amounts of metals compared to the hexagonal system. From these results, it was concluded that the electrokinetic process could be effective at remediating As-, Cu-, and Pb-contaminated paddy rice field in situ. PMID:26032450

  17. Evaluation of the distribution patterns of Pb, Cu and Cd from MSWI fly ash during thermal treatment by sequential extraction procedure.

    PubMed

    Chou, Jing-Dong; Wey, Ming-Yen; Chang, Shih-Hsien

    2009-03-15

    Municipal solid waste incinerator (MSWI) fly ash was frequently classified as hazardous materials as the metals' concentration of toxicity characteristic leaching procedure (TCLP) exceeded regulations. Many studies have focused on reducing the concentration of TCLP using thermal treatment and increasing the application of thermally treated slag. However, the metal patterns in MSWI fly ash with or without thermal treatment have seldom been addressed. The main objective of this study was evaluation of the distribution patterns of Pb, Cu and Cd from MSWI fly ash during thermal treatment by sequential extraction procedure. The experimental parameters included the form of pretreatment, the proportion of bottom ash (bottom ash/fly ash, B/F=0, 0.1 and 1) and the retention time. The results indicated that (1) In comparison to raw fly ash, the distribution patterns of Pb, Cu and Cd become stable in thermally treated slag. (2) Washing pretreatment caused the Pb pattern to become stable, while the influence on Cu and Cd were not significant. (3) The distribution patterns of Pb, Cu, and Cd became more stable as the retention time increased. (4) Adding bottom ash could make the distribution patterns of Pb and Cd more stable. PMID:18614278

  18. Pine bark as bio-adsorbent for Cd, Cu, Ni, Pb and Zn: batch-type and stirred flow chamber experiments.

    PubMed

    Cutillas-Barreiro, L; Ansias-Manso, L; Fernández-Calviño, D; Arias-Estévez, M; Nóvoa-Muñoz, J C; Fernández-Sanjurjo, M J; Álvarez-Rodríguez, E; Núñez-Delgado, A

    2014-11-01

    The objective of this work was to determine the retention of five metals on pine bark using stirred flow and batch-type experiments. Resulting from batch-type kinetic experiments, adsorption was rapid, with no significant differences for the various contact times. Adsorption was between 98 and 99% for Pb(2+), 83-84% for Cu(2+), 78-84% for Cd(2+), 77-83% for Zn(2+), and 70-75% for Ni(2+), and it was faster for low concentrations, with Pb suffering the highest retention, followed by Cu, Cd, Ni and Zn. The fitting to the Freundlich and Langmuir models was satisfactory. Desorption increased in parallel to the added concentrations, with Pb always showing the lowest levels. Stirred flow chamber experiments showed strong hysteresis for Pb and Cu, sorption being mostly irreversible. The differences affecting the studied heavy metals are mainly due to different affinity for the adsorption sites. Pine bark can be used to effectively remove Pb and Cu from polluted environments. PMID:24973614

  19. Multifunctional nanocomposites Fe3O4@SiO2-EDTA for Pb(II) and Cu(II) removal from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Fu, Ruiqi; Sun, Yue; Zhou, Xiaoxin; Baig, Shams Ali; Xu, Xinhua

    2016-04-01

    In this study, EDTA-functionalized Fe3O4 (Fe3O4@SiO2-EDTA) was prepared by silanization reaction between N-(trimethoxysilylpropyl) ethylenediamine triacetic acid (EDTA-silane) and hydroxyl groups for Pb(II) and Cu(II) removal from aqueous solutions. Fe3O4@SiO2-EDTA composites were characterized using SEM, TEM, EDX, FTIR, XPS, TGA and saturated magnetization techniques. Maximum Pb(II) adsorption capacity was found to be 114.94 mg g-1 with SiO2/EDTA molar ratio of 2.5:1. The adsorption rate was significantly fast and the equilibrium was reached within 10 min. The optimum pH was recorded to be 5.0. The maximum adsorption capacity of the studied heavy metal ions calculated by Langmuir model followed the order: Cu(II) (0.58 mmol g-1) > Pb(II) (0.55 mmol g-1) ≈ Ni(II) (0.55 mmol g-1) > Cd(II) (0.45 mmol g-1). Moreover, Pb(II) and Cu(II) adsorption capacities were not significantly affected by co-existing cations and NOM. These results suggested that this adsorbent can be considered as a promising adsorbent to remove Pb(II) and Cu(II) from wastewaters.

  20. The effect of model soil contamination with Cr, Cu, Ni, and Pb on the biological properties of soils in the dry steppe and semidesert regions of southern Russia

    NASA Astrophysics Data System (ADS)

    Kolesnikov, S. I.; Spivakova, N. A.; Kazeev, K. Sh.

    2011-09-01

    Model soil contamination with Cr, Cu, Ni, and Pb in the dry steppes and semideserts of southern Russia has worsened the biological soil properties. With respect to the degree of deterioration of the biological properties, the soils can be arranged in the following sequence: dark chestnut soils > chestnut soils > light chestnut soils > brown semidesert soils > sandy brown semidesert soils. The sequence of metal oxides according to the adverse effect on the biological soil properties is as follows: CrO3 > CuO ≥ PbO ≥ NiO.

  1. Oxidation state and magnetic properties of Pb2Sr2Tb1-xYxCu3O8

    NASA Astrophysics Data System (ADS)

    Staub, U.; Soderholm, L.; Skanthakumar, S.; Antonio, Mark R.

    1995-10-01

    L3-edge x-ray absorption, inelastic neutron scattering (INS), and magnetic susceptibility experiments are used to characterize the electronic properties of Tb in Pb2Sr2TbCu3O8. The x-ray absorption results indicate that Tb is trivalent and show no evidence for strong hybridization between Tb and the CuO2 bands. The observation of three peaks of magnetic origin in the INS experiments is also a clear indication of the trivalent state of Tb. These peaks are assigned to crystalline electric-field (CEF) transitions, and their energies and intensities are consistent with the CEF potential expected for a trivalent rare earth in the Pb2Sr2RCu3O8 lattice. The low-energy response in the INS spectra at low temperatures is described using the mean-field approximation. Single crystal and polycrystalline susceptibilities show deviations from calculations and differ from magnetically diluted samples. These deviations are observed for temperatures less than 120 K and we interpret this as the onset temperature of the magnetic Tb-Tb short-range correlations. This interpretation is supported by the temperature dependence of the magnetic INS intensities at low energies. The onset temperature, estimated at 120 K, is more than an order of magnitude higher than seen in any related system, as well as much higher than the two-dimensional long-range ordering temperature at T=5.5 K. This unusual behavior is understood in terms of the highly two-dimensional nature of the lattice combined with the strongly Ising-like magnetic properties. In addition to the Tb-Tb correlations, the susceptibility experiments on a magnetically dilute sample indicate a weak rare-earth Cu exchange interaction.

  2. Re-Os and U-Pb geochronology of the Laochang Pb-Zn-Ag and concealed porphyry Mo mineralization along the Changning-Menglian suture, SW China: implications for ore genesis and porphyry Cu-Mo exploration

    NASA Astrophysics Data System (ADS)

    Deng, Xiao-Dong; Li, Jian-Wei; Zhao, Xin-Fu; Wang, Hong-Qiang; Qi, Liang

    2016-02-01

    Numerous polymetallic volcanogenic massive sulfide (VMS), vein, and replacement deposits are distributed along the Changning-Menglian suture zone in Sanjiang Tethyan metallogenic province, SW China. Laochang is the largest Pb-Zn-Ag vein and replacement deposit in this area, with a proven reserve of 0.51 Mt Pb, 0.34 Mt Zn, and 1,737 t Ag. Its age and relationship to magmatic events and VMS deposits in the region, however, have long been debated. In this paper, we present pyrite Re-Os and titanite U-Pb ages aiming to provide significant insights into the timing and genesis of the Pb-Zn-Ag mineralization. Pyrite grains in textural equilibrium with galena, sphalerite, and chalcopyrite from stratabound Pb-Zn-Ag and Cu-bearing Pb-Zn-Ag orebodies have a Re-Os isochron age of 45.7 ± 3.1 Ma (2 σ, mean square weighted deviation (MSWD) = 0.45), whereas titanite grains intergrown with sulfide minerals yield a weighted mean 206Pb/238U age of 43.4 ± 1.2 Ma (2 σ, n = 8). A Mo-mineralized granitic porphyry intersected by recent drilling below the Laochang Pb-Zn-Ag ores yields a zircon U-Pb age of 44.4 ± 0.4 Ma (2 σ, n = 12). Within analytical uncertainties, the ages of the Pb-Zn-Ag deposit and the concealed Mo-mineralized porphyry are indistinguishable, indicating that they are products of a single magmatic hydrothermal system. The results show that Laochang Pb-Zn-Ag deposit is significantly younger than the host mafic volcanic rock (zircon U-Pb age of 320.8 ± 2.7 Ma; 2 σ, n = 12) and Silurian VMS deposits along the Changning-Menglian suture zone, arguing against its origin as a Carboniferous VMS deposit as many researchers claimed. The initial 187Os/188Os ratio (0.540 ± 0.012) obtained from the pyrite Re-Os isochron suggests that metals were likely derived from the granitic porphyry that formed from a hybrid magma due to mixing of crustal- and mantle-derived melts, rather than from the mafic volcanic host rocks as previously thought. Our results favor that the Laochang

  3. Highly efficient and mild electrochemical mineralization of long-chain perfluorocarboxylic acids (C9-C10) by Ti/SnO2-Sb-Ce, Ti/SnO2-Sb/Ce-PbO2, and Ti/BDD electrodes.

    PubMed

    Lin, Hui; Niu, Junfeng; Xu, Jiale; Huang, Haiou; Li, Duo; Yue, Zhihan; Feng, Chenghong

    2013-11-19

    The electrochemical mineralization of environmentally persistent long-chain perfluorinated carboxylic acids (PFCAs), i.e., perfluorononanoic acid (C8F17COOH, PFNA) and perfluorodecanoic acid (C9F19COOH, PFDA) was investigated in aqueous solutions (0.25 mmol L(-1)) over Ti/SnO2-Sb-Ce (SnO2), Ti/SnO2-Sb/Ce-PbO2 (PbO2), and Ti/BDD (BDD) anodes under galvanostatic control at room temperature. Based on PFCA decay rate, total organic carbon (TOC) reduction, defluorination ratio, safety, and energy consumption, the performance of PbO2 electrode was comparable with that of BDD electrode. After 180 min electrolysis, the PFNA removals on BDD and PbO2 electrodes were 98.7 ± 0.4% and 97.1 ± 1.0%, respectively, while the corresponding PFDA removals were 96.0 ± 1.4% and 92.2 ± 1.9%. SnO2 electrode yielded lower PFCA removals and led to notable secondary pollution by Sb ions. The primary mineralization product, F(-), as well as trace amounts of intermediate PFCAs with shortened chain lengths, were detected in aqueous solution after electrolysis. On the basis of these results, a degradation mechanism including three potential routes is proposed: via formation of short-chain PFCAs by stepwise removal of CF2; direct mineralization to CO2 and HF; conversion to volatile fluorinated organic compounds. The results presented here demonstrate that electrochemical technique exhibits high efficiency in mineralizing PFNA and PFDA under mild conditions, and is promising for the treatment of long-chain PFCAs in wastewater. PMID:24164589

  4. Contrasting low-dimensional magnetism in the 3D metal-organic frameworks [Cu(VF6)(pyz)2]4H2O and [Cu(HF2)(pyz)2]SbF6 (pyz = pyrazine)

    NASA Astrophysics Data System (ADS)

    Manson, Jamie; Schlueter, John; Goddard, Paul; Singleton, John; McDonald, Ross; Ayala-Valenzuela, Oscar; Lancaster, Tom; Blundell, Stephen

    2012-02-01

    [Cu(VF6)(pyz)2]4H2O (1) and [Cu(HF2)(pyz)2]SbF6 (2) form tetragonal frameworks that consist of 2D [Cu(pyz)2]^2+ square lattices that are linked in 3D by bridging VF6^2- (1) or HF2^- (2) anions. Magnetic susceptibility data shows apparent paramagnetism, although not simple Curie-Weiss behavior, in 1. For 2, a broad maximum in χ(T) at 12.5 K and a sharp kink at 4.3 K indicate short- (SRO) and long-range (LRO) magnetic ordering, respectively. Additional experimental data for 1 (e.g., heat capacity and μ^+SR) however, indicate that a LRO state occurs below 3.6 K whereas pulsed-field magnetization data suggest a superposition of AFM Cu^2+ layers and fluctuating V^4+ moments. The structural and magnetic behavior of 1 and 2 will be described as well as possible new directions.

  5. First U-Pb isotopic data on zircon from andesite of the Saf'yanovka Cu-bearing massive sulfide deposit (Middle Urals)

    NASA Astrophysics Data System (ADS)

    Ronkin, Yu. L.; Pritchin, M. E.; Soroka, E. I.; Gerdes, A.; Puchkov, V. N.; Busharina, S. V.

    2016-07-01

    New results of U-Pb LA ICP-MS dating of zircon from andesite samples cropping out on the western wall of the Saf'yanovka quarry (57°22'58.88″ N, 61°31'50.85″ E) in the synonymous Cu-Zn-bearing massive sulfide deposit of the Urals type are considered. The position of data points of the U-Pb systematics in the 207Pb/235U-206Pb/238U plot determines a cluster practically corresponding to the concordant U-Pb age: 422.8 ± 2.0 Ma. This date indicates for the first time the presence of Pridolian volcanogenic rocks in the East Urals megazone of the Middle Urals.

  6. The potential of Lemna gibba L. and Lemna minor L. to remove Cu, Pb, Zn, and As in gallery water in a mining area in Keban, Turkey.

    PubMed

    Sasmaz, Merve; Arslan Topal, Emine Işıl; Obek, Erdal; Sasmaz, Ahmet

    2015-11-01

    This study was designed to investigate removal efficiencies of Cu, Pb, Zn, and As in gallery water in a mining area in Keban, Turkey by Lemna gibba L. and Lemna minor L. These plants were placed in the gallery water of Keban Pb-Zn ore deposits and adapted individually fed to the reactors. During the study period (8 days), the plant and water samples were collected daily and the temperature, pH, and electric conductivity of the gallery water were measured daily. The plants were washed, dried, and burned at 300 °C for 24 h in a drying oven. These ash and water samples were analyzed by ICP-MS to determine the amounts of Cu, Pb, Zn, and As. The Cu, Pb, Zn and As concentrations in the gallery water of the study area detected 67, 7.5, 7230, and 96 μg L(-1), respectively. According to the results, the obtained efficiencies in L. minor L. and L. gibba L. are: 87% at day 2 and 36% at day 3 for Cu; 1259% at day 2 and 1015% at day 2 for Pb; 628% at day 3 and 382% at day 3 for Zn; and 7070% at day 3 and 19,709% at day 2 for As, respectively. The present study revealed that both L. minor L. and L. gibba L. had very high potential to remove Cu, Pb, Zn, and As in gallery water contaminated by different ores. PMID:26332457

  7. Elastic properties of superconducting Pb (1+ x)/2 Cu (1- x)/2 (Sr 1- yCa y) 2(Y 1- xCa x)Cu 2O 7+ δ

    NASA Astrophysics Data System (ADS)

    Sugiyama, Jun; Isawa, Kazuyuki; Yamauchi, H.

    1995-02-01

    Using a vibrating reed technique, internal friction (Q-1) and Young's-modulus sound velocity (VE) were measured for polycrystalline samples of two types of superconducting Pb0.75Cu0.25(Sr0.9Ca0.1)2(Y0.5Ca0.5)Cu2O7+δ (Tc = 58 and 48 K) and insulating Pb0.5Cu0.5Sr2YCu2O7 in the temperature range between 30 and 300 K. For each of the samples, a broad peak was observed at 180 K in the Q-1 vs. T curve. For superconducting sampls, VE increased monotonically with lowering temperature. Moreover, there appeared to be a distinct change in slope of VE (dVE/dT) around 230 K. For an insulating sample, as temperature lowered, VE increased monotonically without any obvious change in dVE/dT. Furthermore, it was found that the temperature dependence of the magnitude of slope (-dVE/dT) was akin to that of Q-1 for each sample. These behaviors were thought to be attributable to collective displacements of oxygen atoms and/or Pb and Cu atoms in the (Pb,Cu)-O plane.

  8. Distribution of Cd, Pb, Zn and Cu and their chemical speciations in soils from a peri-smelter area in northeast China

    NASA Astrophysics Data System (ADS)

    Du, Ping; Xue, Nandong; Liu, Li; Li, Fasheng

    2008-07-01

    An exploratory study on soil contamination of heavy metals was carried out surrounding Huludao zinc smelter in Liaoning province, China. The distribution of total heavy metals and their chemical speciations were investigated. The correlations between heavy metal speciations and soil pH values in corresponding sites were also analyzed. In general, Cd, Zn, Pb, Cu and As presented a significant contamination in the area near the smelter, comparied with Environmental Quality Standards for Soils in China. The geoaccumulation index showed the degree of contamination: Cd > Zn > Pb > Cu > As. There was no obvious pollution of Cr and Ni in the studied area. The speciation analysis showed that the dominant fraction of Cd and Zn was the acid soluble fraction, and the second was the residual fraction. Pb was mostly associated with the residual fraction, which constituted more than 50% of total concentration in all samples. Cu in residual fraction accounted for a high percentage (40-80%) of total concentration, and the proportion of Cu in the oxidizable fraction is higher than that of other metals. The distribution pattern of Pb and Zn was obviously affected by soil pH. It seemed that Pb and Zn content in acid solution fraction increased with increasing soil pH values, while Cd content in acid soluble fraction accounted for more proportion in neutral and alkaline groups than acidic one. The fraction distribution patterns of Cu in three pH groups were very similar and independent of soil pH values. And the residual fraction of Cu took a predominant part (50%) of the total content.

  9. Immobilization of Cu(II), Pb(II) and Cd(II) by the addition of rice straw derived biochar to a simulated polluted Ultisol.

    PubMed

    Jiang, Jun; Xu, Ren-kou; Jiang, Tian-yu; Li, Zhuo

    2012-08-30

    To develop new remediation methods for acidic soils polluted by heavy metals, the chemical fractions of Cu(II), Pb(II) and Cd(II) in an Ultisol with and without rice straw biochar were compared and the effect of biochar incorporation on the mobility and bioavailability of these metals was investigated. In light of the decreasing zeta potential and increasing CEC, the incorporation of biochar made the negative soil surface charge more negative. Additionally, the soil pH increased markedly after the addition of biochar. These changes in soil properties were advantageous for heavy metal immobilization in the bulk soil. The acid soluble Cu(II) and Pb(II) decreased by 19.7-100.0% and 18.8-77.0%, respectively, as the amount of biochar added increased. The descending range of acid soluble Cd(II) was 5.6-14.1%, which was much lower than that of Cu(II) and Pb(II). When 5.0 mmol/kg of these heavy metals was added, the reducible Pb(II) for treatments containing 3% and 5% biochar was 2.0 and 3.0 times higher than that of samples without biochar, while the reducible Cu(II) increased by 61.6% and 132.6% for the corresponding treatments, respectively. When 3% and 5% biochar was added, the oxidizable portion of Pb(II) increased by 1.18 and 1.94 times, respectively, while the oxidizable portion of Cu(II) increased by 8.13 and 7.16 times, respectively, primarily due to the high adsorption affinity of functional groups of biochar to Cu(II). The residual heavy metal contents were low and changed little with the incorporation of biochar. PMID:22704774

  10. Mass change calculations of hydrothermal alterations within the volcanogenic metasediments hosted Cu-Pb (-Zn) mineralization at Halilar area, NW Turkey

    NASA Astrophysics Data System (ADS)

    Kiran Yildirim, Demet; Abdelnasser, Amr; Doner, Zeynep; Kumral, Mustafa

    2016-04-01

    The Halilar Cu-Pb (-Zn) mineralization that is formed in the volcanogenic metasediments of Bagcagiz Formation at Balikesir province, NW Turkey, represents locally vein-type deposit as well as restricted to fault gouge zone directed NE-SW along with the lower boundary of Bagcagiz Formation and Duztarla granitic intrusion in the study area. Furthermore, This granite is traversed by numerous mineralized sheeted vein systems, which locally transgress into the surrounding metasediments. Therefore, this mineralization closely associated with intense hydrothermal alteration within brecciation, and quartz stockwork veining. The ore mineral assemblage includes chalcopyrite, galena, and some sphalerite with covellite and goethite formed during three phases of mineralization (pre-ore, main ore, and supergene) within an abundant gangue of quartz and calcite. The geologic and field relationships, petrographic and mineralogical studies reveal two alteration zones occurred with the Cu-Pb (-Zn) mineralization along the contact between the Bagcagiz Formation and Duztarla granite; pervasive phyllic alteration (quartz, sericite, and pyrite), and selective propylitic alteration (albite, calcite, epidote, sericite and/or chlorite). This work, by using the mass balance calculations, reports the mass/volume changes (gain and loss) of the chemical components of the hydrothermal alteration zones associated with Halilar Cu-Pb (-Zn) mineralization at Balikesir area (Turkey). It revealed that the phyllic alteration has enrichments of Si, Fe, K, Ba, and LOI with depletion of Mg, Ca, and Na reflect sericitization of alkali feldspar and destruction of ferromagnesian minerals. This zone has high Cu and Pb with Zn contents represents the main mineralized zone. On the other hand, the propylitic zone is characterized by addition of Ca, Na, K, Ti, P, and Ba with LOI and Cu (lower content) referring to the replacement of plagioclase and ferromagnesian minerals by albite, calcite, epidote, and sericite

  11. Determination of Cu, Zn and Pb in scalp hair from a selected population in Penang using the XRF method

    NASA Astrophysics Data System (ADS)

    Aldroobi, Khalid Saleh Ali; Shukri, A.; Munem, Eid Mahmoud Eid Abdel; Bauk, Sabar; Marashdeh, Mohammad Wasef; Amin, Yahye Abbas

    2012-06-01

    The state of Penang encompasses an industrial region with a potential for the existence of a variety of industrial pollutants. Such pollutants would certainly have a possible impact effect on the environment and the people. The determination of trace elements levels in hair which is well known as a method for environmental exposure monitoring, evaluation of heavy metal poisoning, assessment of nutrient levels and disease diagnoses, is chosen here as the method to determine the possible exposure to possible pollutants in the form of unwanted trace elements. The natural levels of trace elements in hair are hence monitored first as reference values for the assessment of the possible human contamination levels. In this work the concentrations of Cu, Zn and Pb in human scalp hair of 50 residents of Penang were determined using XRF. The results of this study were compared with the results obtained in other cities where such measurements have also been carried out.

  12. Increased ability of transgenic plants expressing the bacterial enzyme ACC deaminase to accumulate Cd, Co, Cu, Ni, Pb, and Zn.

    PubMed

    Grichko, V P; Filby, B; Glick, B R

    2000-07-28

    Transgenic tomato plants Lycopersicon esculentum (Solanaceae) cv. Heinz 902 expressing the bacterial gene 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, under the transcriptional control of either two tandem 35S cauliflower mosaic virus promoters (constitutive expression), the rolD promoter from Agrobacterium rhizogenes (root specific expression) or the pathogenesis related PRB-1b promoter from tobacco, were compared to non-transgenic tomato plants in their ability to grow in the presence of Cd, Co, Cu, Mg, Ni, Pb, or Zn and to accumulate these metals. Parameters that were examined include metal concentration and ACC deaminase activity in both plant shoots and roots; root and shoot development; and leaf chlorophyll content. In general, transgenic tomato plants expressing ACC deaminase, especially those controlled by the PRB-1b promoter, acquired a greater amount of metal within the plant tissues, and were less subject to the deleterious effects of the metals on plant growth than were non-transgenic plants. PMID:10936659

  13. Impact of the earthworm Lumbricus terrestris (L.) on As, Cu, Pb and Zn mobility and speciation in contaminated soils.

    PubMed

    Sizmur, Tom; Palumbo-Roe, Barbara; Watts, Michael J; Hodson, Mark E

    2011-03-01

    To assess the risks that contaminated soils pose to the environment properly a greater understanding of how soil biota influence the mobility of metal(loid)s in soils is required. Lumbricus terrestris L. were incubated in three soils contaminated with As, Cu, Pb and Zn. The concentration and speciation of metal(loid)s in pore waters and the mobility and partitioning in casts were compared with earthworm-free soil. Generally the concentrations of water extractable metal(loid)s in earthworm casts were greater than in earthworm-free soil. The impact of the earthworms on concentration and speciation in pore waters was soil and metal specific and could be explained either by earthworm induced changes in soil pH or soluble organic carbon. The mobilisation of metal(loid)s in the environment by earthworm activity may allow for leaching or uptake into biota. PMID:21185630

  14. Anthropogenically derived changes in the sedimentary flux of Mg, Cr, Ni, Cu, Zn, Hg, Pb, and P in Lough Neagh, Northern Ireland

    SciTech Connect

    Rippey, B.; Murphy, R.J.; Kyle, S.W.

    1982-01-01

    The concentration-depth behavior of Mg, Cr, Ni, Cu, Zn, Hg, Pb, and P in three sediment cores from a central site in Lough Neagh, Northern Ireland, was examined for changes in the sedimentary flux of these elements. Two main periods of change were found. A change in the catchment erosion-leaching regime in the 17th century, caused by widespread and comprehensive woodland clearance, produced increased sedimentary Mg, Cu, and Pb concentrations. A second and larger change occurred after about 1880 A.D. Cr, Cu, Zn, Hg, Pb, and P, and , to a lesser extent, Ni concentrations increase toward the sediment surface. Differing P and trace-metal profiles, a comparison of the estimated anthropogenic sedimentary flux with background atmospheric contributions, and a general comparison with other situations all suggest that background atmospheric sources make a substantial contribution to the more recent Cu, Zn, Hg, and Pb sedimentary contamination. The trace-metal contamination of Lough Neagh is part of a global pattern.

  15. CORRELATION OF THE PARTITIONING OF DISSOLVED ORGANIC MATTER FRACTIONS WITH THE DESORPTION OF CD, CU, NI, PB AND ZN FROM 18 DUTCH SOILS

    EPA Science Inventory

    Eighteen Dutch soils were extracted in aqueous solutions at varying pH. Extracts were analyzed for Cd, Cu, Ni, Pb and Zn by ICP-AES. Extract dissolved organic carbon (DOC) was also concentrated onto a macroreticular resin and fractionation into three operationally defined fract...

  16. U-Pb and Ar-Ar geochronology of the Fujiawu porphyry Cu-Mo deposit, Dexing district, Southeast China: Implications for magmatism, hydrothermal alteration, and mineralization

    NASA Astrophysics Data System (ADS)

    Li, Xiaofeng; Hu, Ruizhong; Rusk, Brian; Xiao, Rong; Wang, Cuiyun; Yang, Feng

    2013-09-01

    The Fujiawu porphyry Cu-Mo deposit is one of several porphyry Cu-Mo deposits in the Dexing district, Jiangxi Province, Southeast China. New zircon SHRIMP U-Pb data yield a weighted mean 206Pb/238U age of 172.0 ± 2.1 and 168.5 ± 1.4 Ma from weakly altered granodiorite porphyry and quartz diorite porphyry, respectively. Two hydrothermal biotites from granodiorite porphyry give an Ar-Ar step-heating plateau age of 169.9 ± 1.8 and 168.7 ± 1.8 Ma. Hydrothermal apatite exsolved from altered biotite yields an isotope dilution thermal ionization mass spectrometry isochron age of 164.4 ± 0.9 Ma. The apatite age is similar to the ages obtained from hydrothermal rutile (165.0 ± 1.1 and 164.8 ± 1.6 Ma) and indicates that the magmatism and hydrothermal activity in the Fujiawu deposit occurred in the Middle Jurassic. Hydrothermal fluid circulation related to multiple stages of magma emplacement resulted in Cu-Mo mineralization in the Fujiawu porphyry deposit. The zircon SHRIMP U-Pb ages and the published molybdenite Re-Os age (170.9 ± 1.5 Ma) represent the timing of magma crystallization and Mo mineralization, whereas the rutile and apatite U-Pb ages reflect the timing of Cu mineralization following quartz diorite emplacement. The data suggest slow cooling after emplacement of the quartz diorite porphyry.

  17. Heavy Metals (Cd, Cu, Cr, Pb and Zn) in Meretrix meretrix Roding, Water and Sediments from Estuaries in Sabah, North Borneo

    ERIC Educational Resources Information Center

    Abdullah, Mohd. Harun; Sidi, Jovita; Aris, Ahmad Zaharin

    2007-01-01

    Concentrations of heavy metals (Cd, Cu, Cr, Pb and Zn) in tissues of Meretrix meretrix Roding (M. meretrix R.), water and sediments from two estuaries were determined. One estuary is located in an urban area of Kota Kinabalu (Likas estuary) and the other in a rural district of Kota Belud (Kota Belud estuary), where both are in Sabah, North of…

  18. Silurian U-Pb zircon age (LA-ICP-MS) of granitoids from the Zelenodol Cu-porphyry deposit, Southern Urals

    NASA Astrophysics Data System (ADS)

    Grabezhev, A. I.; Ronkin, Yu. L.; Puchkov, V. N.; Shardakova, G. Yu.; Azovskova, O. B.; Gerdes, A.

    2016-01-01

    The Zelenodol porphyry Cu-(Au, Mo) deposit located about 65 km SSW of the city of Chelyabinsk is confined to the western part of the West Uralian Volcanogenic Megazone. The concordant U-Pb age of zircons from ore-bearing island-arc diorite porphyryis 418.3 Â ± 2.9 Ma.

  19. Using isotopic dilution to assess chemical extraction of labile Ni, Cu, Zn, Cd and Pb in soils.

    PubMed

    Garforth, J M; Bailey, E H; Tye, A M; Young, S D; Lofts, S

    2016-07-01

    Chemical extractants used to measure labile soil metal must ideally select for and solubilise the labile fraction, with minimal solubilisation of non-labile metal. We assessed four extractants (0.43 M HNO3, 0.43 M CH3COOH, 0.05 M Na2H2EDTA and 1 M CaCl2) against these requirements. For soils contaminated by contrasting sources, we compared isotopically exchangeable Ni, Cu, Zn, Cd and Pb (EValue, mg kg(-1)), with the concentrations of metal solubilised by the chemical extractants (MExt, mg kg(-1)). Crucially, we also determined isotopically exchangeable metal in the soil-extractant systems (EExt, mg kg(-1)). Thus 'EExt - EValue' quantifies the concentration of mobilised non-labile metal, while 'EExt - MExt' represents adsorbed labile metal in the presence of the extractant. Extraction with CaCl2 consistently underestimated EValue for Ni, Cu, Zn and Pb, while providing a reasonable estimate of EValue for Cd. In contrast, extraction with HNO3 both consistently mobilised non-labile metal and overestimated the EValue. Extraction with CH3COOH appeared to provide a good estimate of EValue for Cd; however, this was the net outcome of incomplete solubilisation of labile metal, and concurrent mobilisation of non-labile metal by the extractant (MExtEValue). The Na2H2EDTA extractant mobilised some non-labile metal in three of the four soils, but consistently solubilised the entire labile fraction for all soil-metal combinations (MExt ≈ EExt). Comparison of EValue, MExt and EExt provides a rigorous means of assessing the underlying action of soil chemical extraction methods and could be used to refine long-standing soil extraction methodologies. PMID:27153236

  20. Imaging of Cu, Zn, Pb and U in human brain tumor resections by laser ablation inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Zoriy, M. V.; Dehnhardt, M.; Reifenberger, G.; Zilles, K.; Becker, J. S.

    2006-11-01

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to produce images of element distribution in 20 [mu]m thin tissue sections of primary human brain tumors (glioblastoma multiforme--GBM) and adjacent non-neoplastic brain tissue. The sample surface was scanned (raster area ~1 cm2) with a focused laser beam (wavelength 266 nm, diameter of laser crater 50 [mu]m, and laser power density 1 x 109 W cm-2). The laser ablation system was coupled to a double-focusing sector field ICP-SFMS. Ion intensities of 63Cu+, 64Zn+, 208Pb+, and 238U+ were measured by LA-ICP-MS within the tumor area and the surrounding region invaded by GBM as well as in control tissue. The quantitative determination of copper, zinc, lead and uranium distribution in brain tissues by LA-ICP-MS was performed using prepared matrix-matched laboratory standards doped with these elements of interest. The limits of detection (LODs) obtained for Cu and Zn were 0.34 and 0.14 [mu]g g-1, respectively, while LODs of 12.5 and 6.9 ng g-1 were determined for Pb and U. The concentration and distribution of selected elements are compared between the control tissues and regions affected by GBM. A correlation was found between LA-ICP-MS and receptor-autoradiographic results. As receptor-autoradiographic techniques, a labeling for A1AR and the pBR was employed. Regarding the A1AR, we used the specific A1 adenosine receptor (A1AR)-ligand, 3H-CPFPX [3H-cyclopentyl-3-(3-fluoropropyl)-1-propylxanthine], which has been shown to specifically label the invasive zone around GBMs. The peripheral benzodiazepine receptor was labeled with 3H-Pk11195 [3H-1-(2-chlorphenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline-carboxamide].

  1. Synthesis, physical properties and electronic structure of Sr{sub 1-x}La{sub x}Cu{sub 2}Pn{sub 2} (Pn=P, As, Sb)

    SciTech Connect

    Qin Mingsheng; Yang Chongyin; Wang Yaoming; Yang Zhongtian; Chen Ping; Huang Fuqiang

    2012-03-15

    To explore new series of high-T{sub c} superconductors, Cu-based ternary pnictides of SrCu{sub 2}Pn{sub 2} (Pn=P, As, Sb) with La doping were synthesized at 1073 K from the stoichiometric reaction of the elements. The electrical and magnetic properties as well as the electronic structure were systematically investigated. Absence of superconductive transition was observed over the temperature range from room temperature down to 2 K, and these materials show p-type metal-like conductivity and Pauli paramagnetic behavior. The near E{sub F} bands mainly originate from Cu 3d and Pn np states and the value of total densities of states (DOS) becomes higher as Pn goes from P to Sb. The results provides us with considerable information for a better understanding of the transport properties in pnictides. - Graphical abstract: Sr{sub 1-x}La{sub x}Cu{sub 2}Pn{sub 2} (Pn=P, As, Sb) show metal-like conducting behavior and no superconductive transition was observed from 300 K down to 2 K. Highlights: Black-Right-Pointing-Pointer The superconductivity and electronic structure of Sr{sub 1-x}La{sub x}Cu{sub 2}Pn{sub 2} were investigated. Black-Right-Pointing-Pointer Sr{sub 1-x}La{sub x}Cu{sub 2}Pn{sub 2} show p-type metal-like conducting behavior and paramagnetism. Black-Right-Pointing-Pointer The near E{sub F} electronic structure of SrCu{sub 2}Pn{sub 2} mainly originate from Cu 3d and Pn np states.

  2. Efficient perovskite solar cells based on low-temperature solution-processed (CH3NH3)PbI3 perovskite/CuInS2 planar heterojunctions

    PubMed Central

    2014-01-01

    In this work, the solution-processed CH3NH3PbI3 perovskite/copper indium disulfide (CuInS2) planar heterojunction solar cells with Al2O3 as a scaffold were fabricated at a temperature as low as 250°C for the first time, in which the indium tin oxide (ITO)-coated glass instead of the fluorine-doped tin oxide (FTO)-coated glass was used as the light-incidence electrode and the solution-processed CuInS2 layer was prepared to replace the commonly used TiO2 layer in previously reported perovskite-based solar cells. The influence of the thickness of the as-prepared CuInS2 film on the performance of the ITO/CuInS2(n)/Al2O3/(CH3NH3)PbI3/Ag cells was investigated. The ITO/CuInS2(2)/Al2O3/(CH3NH3)PbI3/Ag cell showed the best performance and achieved power conversion efficiency up to 5.30%. PMID:25278818

  3. Efficient perovskite solar cells based on low-temperature solution-processed (CH3NH3)PbI3 perovskite/CuInS2 planar heterojunctions.

    PubMed

    Chen, Chong; Li, Chunxi; Li, Fumin; Wu, Fan; Tan, Furui; Zhai, Yong; Zhang, Weifeng

    2014-01-01

    In this work, the solution-processed CH3NH3PbI3 perovskite/copper indium disulfide (CuInS2) planar heterojunction solar cells with Al2O3 as a scaffold were fabricated at a temperature as low as 250°C for the first time, in which the indium tin oxide (ITO)-coated glass instead of the fluorine-doped tin oxide (FTO)-coated glass was used as the light-incidence electrode and the solution-processed CuInS2 layer was prepared to replace the commonly used TiO2 layer in previously reported perovskite-based solar cells. The influence of the thickness of the as-prepared CuInS2 film on the performance of the ITO/CuInS2(n)/Al2O3/(CH3NH3)PbI3/Ag cells was investigated. The ITO/CuInS2(2)/Al2O3/(CH3NH3)PbI3/Ag cell showed the best performance and achieved power conversion efficiency up to 5.30%. PMID:25278818

  4. Efficient perovskite solar cells based on low-temperature solution-processed (CH3NH3)PbI3 perovskite/CuInS2 planar heterojunctions

    NASA Astrophysics Data System (ADS)

    Chen, Chong; Li, Chunxi; Li, Fumin; Wu, Fan; Tan, Furui; Zhai, Yong; Zhang, Weifeng

    2014-09-01

    In this work, the solution-processed CH3NH3PbI3 perovskite/copper indium disulfide (CuInS2) planar heterojunction solar cells with Al2O3 as a scaffold were fabricated at a temperature as low as 250°C for the first time, in which the indium tin oxide (ITO)-coated glass instead of the fluorine-doped tin oxide (FTO)-coated glass was used as the light-incidence electrode and the solution-processed CuInS2 layer was prepared to replace the commonly used TiO2 layer in previously reported perovskite-based solar cells. The influence of the thickness of the as-prepared CuInS2 film on the performance of the ITO/CuInS2( n)/Al2O3/(CH3NH3)PbI3/Ag cells was investigated. The ITO/CuInS2(2)/Al2O3/(CH3NH3)PbI3/Ag cell showed the best performance and achieved power conversion efficiency up to 5.30%.

  5. Post-annealing treatment for Cu-TiO2 nanotubes and their use in photocatalytic methyl orange degradation and Pb(II) heavy metal ions removal

    NASA Astrophysics Data System (ADS)

    Sreekantan, Srimala; Mohd Zaki, Syazwani; Lai, Chin Wei; Tzu, Teoh Wah

    2014-07-01

    TiO2 nanotubes were synthesized via electrochemical anodization of Ti foil at 60 V for 1 h in a bath with electrolytes composed of ethylene glycol containing 5 wt.% of NH4F and 1 vol.% of H2O2. The incorporation of optimum Cu2+ ions (1.30 at.%) into TiO2 nanotubes were prepared by using wet impregnation method to improve their photocatalytic methyl orange degradation and Pb(II) heavy metal removal. The small Cu2+ ions were successfully diffused into lattice of TiO2 nanotubes by conducting post-annealing treatment at 400 °C for 4 h in argon atmosphere after wet impregnation. In this manner, optimum Cu2+ ions played a crucial role in suppressing the recombination of charge carriers by forming inter-band states (mismatch of the band energies) within the lattice of Cu-TiO2. The experimental results showed that a maximum of 80% methyl orange removal and 97.3% Pb(II) heavy metal removal at pH 11 under UV irradiation for 5 h. Besides, it was noticed that photocatalytic Pb(II) heavy metal removal was strong dependence on pH of the solution because of the amphoteric character of Cu-TiO2 in an aqueous medium.

  6. Pb-Sr-Nd isotopes in surficial materials at the Pebble Porphyry Cu-Au-Mo Deposit, Southwestern Alaska: can the mineralizing fingerprint be detected through cover?

    USGS Publications Warehouse

    Ayuso, Robert A.; Kelley, Karen D.; Eppinger, Robert G.; Forni, Francesca

    2013-01-01

    The Cretaceous Pebble porphyry Cu-Au-Mo deposit is covered by tundra and glacigenic sediments. Pb-Sr-Nd measurements were done on sediments and soils to establish baseline conditions prior to the onset of mining operations and contribute to the development of exploration methods for concealed base metal deposits of this type. Pebble rocks have a moderate range for 206Pb/204Pb = 18.574 to 18.874, 207Pb/204Pb = 15.484 to 15.526, and 208,Pb/204Pb = 38.053 to 38.266. Mineralized granodiorite shows a modest spread in 87Sr/86Sr (0.704354–0.707621) and 143Nd/144Nd (0.512639–0.512750). Age-corrected (89 Ma) values for the granodiorite yield relatively unradiogenic Pb (e.g., 207Pb/204Pb 87Sr/86Sr, and positive values of ɛNd (1.00–4.52) that attest to a major contribution of mantle-derived source rocks. Pond sediments and soils have similar Pb isotope signatures and 87Sr/86Sr and 143Nd/144Nd values that resemble the mineralized granodiorites. Glacial events have obscured the recognition of isotope signatures of mineralized rocks in the sediments and soils. Baseline radiogenic isotope compositions, prior to the onset of mining operations, reflect natural erosion, transport and deposition of heterogeneous till sheets that included debris from barren rocks, mineralized granodiorite and sulfides from the Pebble deposit, and other country rocks that pre- and postdate the mineralization events. Isotopic variations suggest that natural weathering of the deposit is generally reflected in these surficial materials. The isotope data provide geochemical constraints to glimpse through the extensive cover and together with other geochemical observations provide a vector to concealed mineralized rocks genetically linked with the Pebble deposit.

  7. Static and Dynamic Magnetic Response of Fragmented Haldane-like Spin Chains in Layered Li3Cu2SbO6

    NASA Astrophysics Data System (ADS)

    Koo, Changhyun; Zvereva, Elena A.; Shukaev, Igor L.; Richter, Michael; Stratan, Mikhail I.; Vasiliev, Alexander N.; Nalbandyan, Vladimir B.; Klingeler, Rüdiger

    2016-08-01

    The structure and the magnetic properties of layered Li3Cu2SbO6 are investigated by powder X-ray diffraction, static susceptibility, and electron spin resonance studies up to 330 GHz. The XRD data experimentally verify the space group C2/m with halved unit cell volume in contrast to previously reported C2/c. In addition, the data show significant Li/Cu-intersite exchange. Static magnetic susceptibility and ESR measurements show two magnetic contributions, i.e., quasi-free spins at low-temperature and a spin-gapped magnetic subsystem, with about half of the spins being associated to each subsystem. The data suggest ferromagnetic-antiferromagnetic alternating chains with JFM = -285 K and JAFM = 160 K with a significant amount of Li-defects in the chains. The results are discussed in the scenario of fragmented 1D S = 1 AFM chains with a rather high defect concentration of about 17% and associated S = 1/2 edge states of the resulting finite Haldane chains.

  8. Enhanced thermoelectric performance of Cu2Se/Bi0.4Sb1.6Te3 nanocomposites at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Li, Y. Y.; Qin, X. Y.; Li, D.; Zhang, J.; Li, C.; Liu, Y. F.; Song, C. J.; Xin, H. X.; Guo, H. F.

    2016-02-01

    Bi2Te3-based thermoelectric materials with large thermoelectric figure of merit, ZT, at elevated temperatures are advantageous in power generation by using the low-grade waste heat. Here, we show that incorporation of small proportion (0.3 vol. %) of nanophase Cu2Se into BiSbTe matrix causes an enhanced high-temperature thermopower due to elevated energy filtering of carriers and inhibition of minority transport besides enhanced phonon blocking from scattering at interfaces, which concurrently result in an ˜20% increase in the power factor and an ˜60% reduction in the lattice thermal conductivity at 488 K. As a result, ZT = 1.6 is achieved at 488 K in the composite system with 0.3 vol. % of Cu2Se. Significantly, its ZT is larger than unit in broad high-temperature range (e.g., ZT = 1.3 at 400 K and ZT = 1.6 at 488 K), which makes this material to be attractive for applications in energy harvesting from the low-grade waste heat.

  9. Spin-orbital short-range order in the honeycomb-based quantum magnet Ba3CuSb2O9

    NASA Astrophysics Data System (ADS)

    Nakatsuji, Satoru

    2013-03-01

    The realization of quantum correlated matter beyond one dimension has been vigorously pursued in geometrically frustrated spin systems for decades. In frustrated magnetic materials, however, symmetry breaking of orbital and chemical origin is usually found to induce semi-classical spin freezing. In this talk, I present a contrast case where spins and possibly orbitals remain in a liquid state down to low temperature even in a highly disordered structure of 6H-perovskite Ba3CuSb2O9. Our comprehensive experimental analysis indicates that the geometrical frustration of Wannier's Ising antiferromagnet on a triangular lattice can be exploited to build a nano-structured bipartite honeycomb lattice from electric dipolar spin-1/2 molecules. Despite a strong local Jahn-Teller distortion about the Cu2+ ion, the resulting spin-orbital random bond lattice not only retains hexagonal symmetry averaged over time and space, but it supports a gapless excitation spectrum without spin freezing down to ultralow temperatures. This is the work based on the collaboration with K. Kuga, K. Kimura, R. Satake, N. Katayama, E. Nishibori, H. Sawa, R. Ishii, M. Hagiwara, F. Bridges, T. U. Ito, W. Higemoto, Y. Karaki, M. Halim, A. A. Nugroho, J. A. Rodriguez-Rivera, M. A. Green, C. Broholm. This work is partially supported by Grant-in-Aid for Scientific Research (No. 20340089,21684019) from JSPS, by Grant-in-Aid for Scientific Research on Priority Areas (No. 1951010,19052003) from MEXT, Japan.

  10. Assessment of waste oyster shells and coal mine drainage sludge for the stabilization of As-, Pb-, and Cu-contaminated soil.

    PubMed

    Moon, Deok Hyun; Cheong, Kyung Hoon; Koutsospyros, Agamemnon; Chang, Yoon-Young; Hyun, Seunghun; Ok, Yong Sik; Park, Jeong-Hun

    2016-02-01

    A novel treatment mix was designed for the simultaneous immobilization of As, Cu, and Pb in contaminated soils using natural (waste oyster shells (WOS)) and industrial (coal mine drainage sludge (CMDS)) waste materials. The treatments were conducted using the standard U.S. sieve size no. 20 (0.85 mm) calcined oyster shells (COS) and CMDS materials with a curing time of 1 and 28 days. The As immobilization treatments were evaluated using the 1-N HCl extraction fluid, whereas the Pb and Cu immobilization treatments were evaluated using the 0.1-N HCl extraction fluid based on the Korean leaching standards. The treatment results showed that the immobilization of As, Cu, and Pb was best achieved using a combination mix of 10 wt% COS and 10 wt% CMDS. This treatment mix was highly effective leading to superior leachability reductions for all three target contaminants (>93 % for As and >99 % for Cu and Pb) for a curing period of 28 days. The X-ray absorption near-edge structure (XANES) results showed that As was present in the form of As(V) in the control sample and that no changes in As speciation were observed following the COS-CMDS treatments. The scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) sample treated with 10 wt% COS and 10 wt% CMDS indicated that As immobilization may be associated with the formation of Ca-As and Fe-As precipitates while Pb and Cu immobilization was most probably linked to calcium silicate hydrates (CSHs) and calcium aluminum hydrates (CAHs). PMID:26411449

  11. Mid-twentieth century increases in anthropogenic Pb, Cd and Cu in central Asia set in hemispheric perspective using Tien Shan ice core

    NASA Astrophysics Data System (ADS)

    Grigholm, B.; Mayewski, P. A.; Aizen, V.; Kreutz, K.; Wake, C. P.; Aizen, E.; Kang, S.; Maasch, K. A.; Handley, M. J.; Sneed, S. B.

    2016-04-01

    High-resolution major and trace element (Al, As, Ca, Cd, Co, Cr, Cu, Fe, Li, Mn, Na, Pb, S, Ti, and V) ice core records from Inilchek glacier (5120 m above sea level) on the northwestern margin of the Tibetan Plateau provide the first multi-decadal ice core record spanning the period 1908-1995 AD in central Tien Shan. The trace element records reveal pronounced temporal baseline trends and concentration maxima characteristic of post-1950 anthropogenic emissions. Examination of Pb, Cd and Cu concentrations, along with non-crustal calculation estimates (i.e. excess (ex) and enrichment factor (EF)), reveal that discernable anthropogenic inputs began during the 1950s and rapidly increased to the late-1970s and early 1980s, by factors up to of 5, 6 and 3, respectively, relative to a 1910-1950 means. Pb, Cd and Cu concentrations between the 1950s-1980s are reflective of large-scale Soviet industrial and agricultural development, including the growth of production and/or consumption of the non-ferrous metals, coal and phosphate fertilizers. NOAA HYSPLIT back-trajectory frequency analysis suggests pollutant sources originating primarily from southern Kazakhstan (e.g. Shymkent and Balkhash) and the Fergana Valley (located in Kazakhstan, Uzbekistan and Kyrgyzstan). Inilchek ice core Pb, Cd and Cu reveals declines during the 1980s concurrent with Soviet economic declines, however, due to the rapid industrial and agricultural growth of western China, Pb, Cd and Cu trends increase during the 1990s reflecting a transition from primarily central Asian sources to emission sources from western China (e.g. Xinjiang Province).

  12. Selective removals of heavy metals (Pb(2+), Cu(2+), and Cd(2+)) from wastewater by gelation with alginate for effective metal recovery.

    PubMed

    Wang, Fei; Lu, Xingwen; Li, Xiao-Yan

    2016-05-01

    A novel method that uses the aqueous sodium alginate solution for direct gelation with metal ions is developed for effective removal and recovery of heavy metals from industrial wastewater. The experimental study was conducted on Pb(2+), Cu(2+), and Cd(2+) as the model heavy metals. The results show that gels can be formed rapidly between the metals and alginate in less than 10min and the gelation rates fit well with the pseudo second-order kinetic model. The optimum dosing ratio of alginate to the metal ions was found to be between 2:1 and 3:1 for removing Pb(2+) and around 4:1 for removing Cu(2+) and Cd(2+) from wastewater, and the metal removal efficiency by gelation increased as the solution pH increased. Alginate exhibited a higher gelation affinity toward Pb(2+) than Cu(2+) and Cd(2+), which allowed a selective removal of Pb(2+) from the wastewater in the presence of Cu(2+) and Cd(2+) ions. Chemical analysis of the gels suggests that the gelation mainly occurred between the metal ions and the COO(-) and OH groups on alginate. By simple calcination of the metal-laden gels at 700°C for 1h, the heavy metals can be well recovered as valuable resources. The metals obtained after the thermal treatment are in the form of PbO, CuO, and CdO nanopowders with crystal sizes of around 150, 50, and 100nm, respectively. PMID:26808245

  13. Evaluating the potential of three Fe- and Mn-(nano)oxides for the stabilization of Cd, Cu and Pb in contaminated soils.

    PubMed

    Michálková, Zuzana; Komárek, Michael; Šillerová, Hana; Della Puppa, Loïc; Joussein, Emmanuel; Bordas, François; Vaněk, Aleš; Vaněk, Ondřej; Ettler, Vojtěch

    2014-12-15

    The potential of three Fe- and Mn-(nano)oxides for stabilizing Cd, Cu and Pb in contaminated soils was investigated using batch and column experiments, adsorption tests and tests of soil microbial activity. A novel synthetic amorphous Mn oxide (AMO), which was recently proposed as a stabilizing amendment, proved to be the most efficient in decreasing the mobility of the studied metals compared to nano-maghemite and nano-magnetite. Its application resulted in significant decreases of exchangeable metal fractions (92%, 92% and 93% decreases of Cd, Cu and Pb concentrations, respectively). The adsorption capacity of the AMO was an order of magnitude higher than those recorded for the other amendments. It was also the most efficient treatment for reducing Cu concentrations in the soil solution. No negative effects on soil microorganisms were recorded. On the other hand, the AMO was able to dissolve soil organic matter to some extent. PMID:25178528

  14. Elaborated 1H NMR study for the ligitional behavior of two thiosemicarbazide derivatives towards some heavy metals (Sn(II), Sb(III), Pb(II) and Bi(III)), thermal, antibacterial and antifungal studies

    NASA Astrophysics Data System (ADS)

    El-Metwaly, Nashwa M.; Refat, Moamen S.

    2011-10-01

    A new series of heavy metal complexes are prepared. Sn(II), Sb(III), Pb(II) and Bi(III) are the metal ions used in complexation with two thiosemicarbazide ligands. The IR and 1H NMR spectra of the free ligands display their presence in thiole-thione forms coincide with each other. The IR spectra of the complexes support the presence of 2:2 molar ratio (M:HL) with HL 1 ligand and 1:1 beside 1:2 with HL 2. The ligand coordinates as bi molecules in some complexes and displays two tautomer forms at the same complex molecule 1H NMR spectra of Sn(II) and Sb(III) complexes were done and comes coincide with IR data. The electronic spectral analysis displays a lower shift appearance in n → π* charge transfer band in most isolated complexes. As well as, a new band is shinned in visible region with Sb(III), Bi(III) complexes and Sn(II)-HL 2. This band is pointed to its use in spectrophotometric analysis for these metal ions. The TG analysis for all isolated compounds was briefly discussed. The molecular modeling parameters support the stability of thiole form of the free ligands in comparing with their thiones by a small difference. The antibacterial and antifungal activities were studied against some organisms and reveal the priority of most investigated complexes.

  15. Effect of biochar on the extractability of heavy metals (Cd, Cu, Pb, and Zn) and enzyme activity in soil.

    PubMed

    Yang, Xing; Liu, Jingjing; McGrouther, Kim; Huang, Huagang; Lu, Kouping; Guo, Xi; He, Lizhi; Lin, Xiaoming; Che, Lei; Ye, Zhengqian; Wang, Hailong

    2016-01-01

    Biochar is a carbon-rich solid material derived from the pyrolysis of agricultural and forest residual biomass. Previous studies have shown that biochar is suitable as an adsorbent for soil contaminants such as heavy metals and consequently reduces their bioavailability. However, the long-term effect of different biochars on metal extractability or soil health has not been assessed. Therefore, a 1-year incubation experiment was carried out to investigate the effect of biochar produced from bamboo and rice straw (at temperatures ≥500 °C) on the heavy metal (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) extractability and enzyme activity (urease, catalase, and acid phosphatase) in a contaminated sandy loam paddy soil. Three rates (0, 1, and 5%) and two mesh sizes (<0.25 and <1 mm) of biochar applications were investigated. After incubation, the physicochemical properties, extractable heavy metals, available phosphorus, and enzyme activity of soil samples were analyzed. The results demonstrated that rice straw biochar significantly (P < 0.05) increased the pH, electrical conductivity, and cation exchange capacity of the soil, especially at the 5% application rate. Both bamboo and rice straw biochar significantly (P < 0.05) decreased the concentration of CaCl2-extractable heavy metals as biochar application rate increased. The heavy metal extractability was significantly (P < 0.01) correlated with pH, water-soluble organic carbon, and available phosphorus in soil. The 5% application rate of fine rice straw biochar resulted in the greatest reductions of extractable Cu and Zn, 97.3 and 62.2%, respectively. Both bamboo and rice straw biochar were more effective at decreasing extractable Cu and Pb than removing extractable Cd and Zn from the soil. Urease activity increased by 143 and 107% after the addition of 5% coarse and fine rice straw biochars, respectively. Both bamboo and rice straw biochars significantly (P < 0.05) increased catalase

  16. Anisotropic Diamagnetism of 110 K Bi-Pb-Sr-Ca-Cu-O

    NASA Astrophysics Data System (ADS)

    Ishida, Takekazu; Sakuma, Takashi; Sasaki, Toku; Kawada, Yuzo

    1989-04-01

    The 110 K Bi compounds have been prepared by means of a Pb-doping technique. The 110 K phase was obtained in an almost single-phase form. The ac susceptibility of the pellet can be interpreted in terms of bulk and coupling contributions. The powdered specimen was molded in a Stycast 1266 under a 8.9 T magnetic field to align the sense of the c axis. We found that the ac susceptibility was very anisotropic with respect to the c axis.

  17. Substitution of chromium for univalent copper in superconducting Pb{sub 2}Sr{sub 2}(Ca, Y)Cu{sub 3}O{sub 8-{delta}}

    SciTech Connect

    Seshadri, R.; Maignan, A.; Hervieu, M.

    1996-11-15

    Following considerations of geometry and the similarity between chromate and carbonate groups in terms of size and charge, the authors have investigated the possibility of replacing the two-coordinate Cu{sup I} in superconducting lead cuprates of the general formula Pb{sub 2}Sr{sub 2}(Ca, Y)Cu{sub 3}O{sub 8} by Cr. A high-resolution electron microscopy study coupled with energy dispersive X-ray analysis on small crystals of the title phases suggests that between 10 and 15% of the Cu{sup 1} can be replaced by Cr. While from the present structural study using HRTEM and Rietveld refinement of X-ray powder data the authors are unable to precisely obtain the oxidation state and oxygen coordination of Cr, the authors suggest in analogy with Cr substitution in other similar cuprates that in the title phases Cu{sup I}O{sub 2} rods are partially replaced by tetrahedral CrO{sub 4}{sup 2-} groups. Infrared spectroscopy supports the presence of CrO{sub 4}{sup 2-} groups. The phases Pb{sub 1.75}Sr{sub 2}Ca{sub 0.2}Y{sub 0.8}Cu{sub 3}O{sub 8-{delta}} and Pb{sub 1.75}Sr{sub 2}Ca{sub 0.2}Y{sub 0.8}Cu{sub 2.85}Cr{sub 0.15}O{sub 8-{delta}} are superconducting as-prepared, but the substitution of Cr for Cu{sup I} results in a decrease of the T{sub C} as well as the superconducting volume fraction.

  18. Factors affecting the partitioning of Cu, Zn and Pb in boulder coatings and stream sediments in the vicinity of a polymetallic sulfide deposit

    USGS Publications Warehouse

    Filipek, L.H.; Chao, T.T.; Carpenter, R.H.

    1981-01-01

    A sequential extraction scheme is utilized to determine the geochemical partitioning of Cu, Zn and Pb among hydrous Mn- and Fe-oxides, organics and residual crystalline silicates and oxides in the minus-80-mesh ( Fe-oxides > Mn-oxides; Zn, Mn-oxides {reversed tilde equals} organics > Fe-oxides; Pb, Fe-oxides > organics > Mn-oxides. In the sediments, organics are the most efficient scavengers of all three ore metals. These results emphasize the importance of organics as sinks for the ore metals, even in environments with high concentrations of Mn- and Fe-oxides. Of the ore metals, Zn appears to be the most mobile, and is partitioned most strongly into the coatings. However, anomaly contrast for hydromorphic Zn, normalized to the MnFe-oxide or organic content, is similar in sediments and coatings. Cu shows the highest anomaly on the boulder coatings, probably due to precipitation of a secondary Cu mineral. In contrast, detrital Pb in the pan concentrates shows a better anomaly than any hydromorphic Pb component. ?? 1981.

  19. Cylindrospermopsis raciborskii (Cyanobacteria) exudates: chemical characterization and complexation capacity for Cu, Zn, Cd and Pb.

    PubMed

    Tonietto, Alessandra Emanuele; Lombardi, Ana Teresa; Vieira, Armando Augusto Henriques; Parrish, Christopher C; Choueri, Rodrigo Brasil

    2014-02-01

    Cylindrospermopsis raciborskii is a cosmopolitan and potentially toxic planktonic Cyanobacteria that produces and exudes copious amounts of dissolved organic materials. This organism dominates the eutrophic reservoir Barra Bonita (Brazil), where it normally blooms throughout the year. This investigation focused on the characterization of such exudates analyzing their capacity to complex copper, zinc, lead and cadmium through the determination of ligand concentration (CL) and conditional stability constant (logK'ML), as well as elemental composition (C, H, N and S), the content of carbohydrates, proteins, lipids and dissolved organic carbon (DOC). The dissolved organic material was fractionated into 3 molecular weights (>30 kDa; 30-10 kDa; 10-3 kDa) and each fraction was analyzed. The results showed that in the >30 kDa and 30-10 kDa fractions carbohydrates dominate over proteins and lipids. Different CL and logK'ML were obtained for the different molecular weight fractions of the excreted organic materials, suggesting high diversity of ligands. In the >30 kDa, there were more complexing sites (CL) for Cu, but higher affinity (K') for Zn. In the 30-10 kDa fraction, the higher CL was for Cd, but the greatest affinities were for Cu and Zn. In the 10-3 kDa fraction, higher CL was obtained for Cd and Zn, while Cu and Cd had the highest strengths of association. In the environment, such diversity of ligands and strengths of association can result in a displacement of metals weakly bound to the EOM, and increase metal buffering capacity of the environment, supporting higher metal inputs before toxic effects are detected in the biota. PMID:24169513

  20. Simultaneous determination of Cd(II), Cu(II), Pb(II), and Zn(II) in citrus essential oils by derivative potentiometric stripping analysis.

    PubMed

    La Pera, Lara; Saitta, Marcello; Di Bella, Giuseppa; Dugo, Giacomo

    2003-02-26

    Citrus essential oils are widely used in the food, cosmetics, and pharmaceutical industries, so the determination of heavy metals content is of great importance to guarantee their quality. The present work deals with the quantification of Cd(II), Cu(II), Pb(II), and Zn(II) in different varieties of citrus essential oils, using derivative potentiometric stripping analysis. Two different metals extraction procedures, involving concentrated hydrochloric acid treatment and acid-alcoholic dissolution, are tested on lemon, mandarin, sweet orange, and bergamot essential oils, and they give very similar results. Cd(II), Cu(II), Pb(II), and Zn(II) recovery tests spanned from 95 to 100.50%, providing evidence that metals quantification remained unaffected by the cleanup steps of the two procedures. The repeatability of the hydrochloric acid extraction method, applied on different varieties of essential oils, is >95.00% for Cd(II), Cu(II), Pb(II), and Zn(II), whereas the repeatability of the acid-alcoholic dissolution method is >93.00% for Cu and Cd only in lemon oil. Detection limits obtained for the four analytes, using both procedures, ranged from 0.10 to 0.98 ng g(-)(1) in lemon, mandarin, sweet orange, and bergamot essential oils. PMID:12590445

  1. Formation of superconducting Bi sub 2-y Pb sub y Sr sub 2 Ca sub 2 Cu sub 3 O sub x from coprecipitated oxalates

    SciTech Connect

    Bernhard, K.; Gritzner, G.; Wang, Xianzhong; Baeuerle, D. )

    1990-06-01

    The conditions for the coprecipitation of Bi{sup 3+}, Pb{sup 2+}, Ca{sup 2+} as oxalates are reported. These oxalates were used as precursors for the formation of Bi{sub 2-y}Pb{sub y}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconducting ceramics. The behavior of the oxalates upon heat treatment was studied by thermogravimetry. Both the oxalates and the superconducting oxides were analyzed and characterized by atomic absorption spectroscopy and by X-ray diffraction.

  2. Time of flight secondary ion mass spectrometry and high-resolution transmission electron microscopy/energy dispersive spectroscopy: a preliminary study of the distribution of Cu2+ and Cu2+/Pb2+ on a Bt horizon surfaces.

    PubMed

    Cerqueira, B; Vega, F A; Serra, C; Silva, L F O; Andrade, M L

    2011-11-15

    Relatively new techniques can help in determining the occurrence of mineral species and the distribution of contaminants on soil surfaces such as natural minerals and organic matter. The Bt horizon from an Endoleptic Luvisol was chosen because of its well-known sorption capability. The samples were contaminated with Cu(2+) and/or Pb(2+) and both sorption and desorption experiments were performed. The preferential distribution of the contaminant species ((63)Cu and (208)Pb) to the main soil components and their associations were studied together with the effectiveness of the surface sorption and desorption processes. The results obtained were compared with non-contaminated samples as well as with previous results obtained by different analytical techniques and advanced statistical analysis. Pb(2+) competes favorably for the sorption sites in this soil, mainly in oxides and the clay fraction. Cu(2+) and Pb(2+) were mainly associated with hematite, gibbsite, vermiculite and chlorite. This study will serve as a basis for further scientific research on the soil retention of heavy metals. New techniques such as spectroscopic imaging and transmission electron microscopy make it possible to check which soil components retain heavy metals, thereby contributing to propose effective measures for the remediation of contaminated soil. PMID:21920666

  3. Chemical ordering rather than random alloying in SbAs

    NASA Astrophysics Data System (ADS)

    Shoemaker, Daniel P.; Chasapis, Thomas C.; Do, Dat; Francisco, Melanie C.; Chung, Duck Young; Mahanti, S. D.; Llobet, Anna; Kanatzidis, Mercouri G.

    2013-03-01

    The semimetallic group-V elements display a wealth of correlated electron phenomena due to a small indirect band overlap that leads to relatively small, but equal, numbers of holes and electrons at the Fermi energy with high mobility. Their electronic bonding characteristics produce a unique crystal structure, the rhombohedral A7 structure, which accommodates lone pairs on each site. Here, we show via single-crystal and synchrotron x-ray diffraction that antimony arsenide (SbAs) is a compound and the A7 structure can display chemical ordering of Sb and As, which were previously thought to mix randomly. Formation of this compound arises due to differences in electronegativity that are common to IV-VI compounds of average group V such as GeTe, SnS, PbS, and PbTe, and also ordered intraperiod compounds such as CuAu and NiPt. High-temperature diffraction studies reveal an order-disorder transition around 550 K in SbAs, which is in stark contrast to IV-VI compounds GeTe and SnTe that become cubic at elevated temperatures but do not disorder. Transport and infrared reflectivity measurements, along with first-principles calculations, confirm that SbAs is a semimetal, albeit with a direct band separation larger than that of Sb or As. Because even subtle substitutions in the semimetals, notably Bi1-xSbx, can open semiconducting energy gaps, a further investigation of the interplay between chemical ordering and electronic structure on the A7 lattice is warranted.

  4. Modeling removal of Cd, Cu, Pb, and Zn in acidic groundwater during neutralization by ambient surface waters and groundwaters

    USGS Publications Warehouse

    Paulson, A.J.; Balistrieri, L.

    1999-01-01

    Removal of Pb, Cu, Zn, and Cd during neutralization of acid rock drainage is examined using model simulations of field conditions and laboratory experiments involving mixing of natural drainage and surface waters or groundwaters. The simulations consider sorption onto hydrous Fe and Al oxides and particulate organic carbon, mineral precipitation, and organic and inorganic solution complexation of metals for two physical systems where newly formed oxides and particulate organic matter are either transported or retained along the chemical pathway. The calculations indicate that metal removal is a strong function of the physical system. Relative to direct discharge of ARD into streams, lower metal removals are observed where ARD enters streamwaters during the latter stages of neutralization by ambient groundwater after most of the Fe has precipitated and been retained in the soils. The mixing experiments, which represent the field simulations, also demonstrated the importance of dissolved metal to particle Fe ratios in controlling dissolved metal removal along the chemical pathway. Finally, model calculations indicate that hydrous Fe oxides and particulate organic carbon are more important than hydrous Al oxides in removing metals and that both inorganic and organic complexation must be considered when modeling metal removal from aquatic systems that are impacted by sulfide oxidation.Removal of Pb, Cu, Zn, and Cd during neutralization of acid rock drainage is examined using model simulations of field conditions and laboratory experiments involving mixing of natural drainage and surface waters or groundwaters. The simulations consider sorption onto hydrous Fe and Al oxides and particulate organic carbon, mineral precipitation, and organic and inorganic solution complexation of metals for two physical systems where newly formed oxides and particulate organic matter are either transported or retained along the chemical pathway. The calculations indicate that metal

  5. Accumulation of Pb and Cu heavy metals in sea water, sediment, and leaf and root tissue of Enhalus sp. in the seagrass bed of Banten Bay

    SciTech Connect

    Fauziah, Faiza Choesin, Devi N.

    2014-03-24

    Banten Bay in Indonesia is a coastal area which has been highly affected by human activity. Previous studies have reported the presence of lead (Pb) and copper (Cu) heavy metals in the seawater of this area. This study was conducted to measure the accumulation of Pb and Cu in seawater, sediment, leaf tissue, and root tissue of the seagrass species Enhalus sp. Sampling was conducted at two observation stations in Banten Bay: Station 1 (St.1) was located closer to the coastline and to industrial plants as source of pollution, while Station 2 (St.2) was located farther away offshore. At each station, three sampling points were established by random sampling. Field sampling was conducted at two different dates, i.e., on 29 May 2012 and 30 June 2012. Samples were processed by wet ashing using concentrated HNO{sub 3} acid and measured using Atomic Absorption Spectrometry (AAS). Accumulation of Pb was only detected in sediment samples in St.1, while Cu was detected in all samples. Average concentrations of Cu in May were as follows: sediment St.1 = 0.731 ppm, sediment St.2 = 0.383 ppm, seawater St.1 = 0.163 ppm, seawater St.2 = 0.174 ppm, leaf St.1 = 0.102 ppm, leaf St.2 = 0.132 ppm, root St.1= 0.139 ppm, and root St.2 = 0.075 ppm. Average measurements of Cu in June were: sediment St.1 = 0.260 ppm, leaf St.1 = 0.335 ppm, leaf St.2 = 0.301 ppm, root St.1= 0.047 ppm, and root St.2 = 0.060 ppm. In June, Cu was undetected in St.2 sediment and seawater at both stations. In May, Cu concentration in seawater exceeded the maximum allowable threshold for water as determined by the Ministry of the Environment. Spatial and temporal variation in Pb and Cu accumulation were most probably affected by distance from source and physical conditions of the environment (e.g., water current and mixing)

  6. Accumulation of Pb and Cu heavy metals in sea water, sediment, and leaf and root tissue of Enhalus sp. in the seagrass bed of Banten Bay

    NASA Astrophysics Data System (ADS)

    Fauziah, Faiza; Choesin, Devi N.

    2014-03-01

    Banten Bay in Indonesia is a coastal area which has been highly affected by human activity. Previous studies have reported the presence of lead (Pb) and copper (Cu) heavy metals in the seawater of this area. This study was conducted to measure the accumulation of Pb and Cu in seawater, sediment, leaf tissue, and root tissue of the seagrass species Enhalus sp. Sampling was conducted at two observation stations in Banten Bay: Station 1 (St.1) was located closer to the coastline and to industrial plants as source of pollution, while Station 2 (St.2) was located farther away offshore. At each station, three sampling points were established by random sampling. Field sampling was conducted at two different dates, i.e., on 29 May 2012 and 30 June 2012. Samples were processed by wet ashing using concentrated HNO3 acid and measured using Atomic Absorption Spectrometry (AAS). Accumulation of Pb was only detected in sediment samples in St.1, while Cu was detected in all samples. Average concentrations of Cu in May were as follows: sediment St.1 = 0.731 ppm, sediment St.2 = 0.383 ppm, seawater St.1 = 0.163 ppm, seawater St.2 = 0.174 ppm, leaf St.1 = 0.102 ppm, leaf St.2 = 0.132 ppm, root St.1= 0.139 ppm, and root St.2 = 0.075 ppm. Average measurements of Cu in June were: sediment St.1 = 0.260 ppm, leaf St.1 = 0.335 ppm, leaf St.2 = 0.301 ppm, root St.1= 0.047 ppm, and root St.2 = 0.060 ppm. In June, Cu was undetected in St.2 sediment and seawater at both stations. In May, Cu concentration in seawater exceeded the maximum allowable threshold for water as determined by the Ministry of the Environment. Spatial and temporal variation in Pb and Cu accumulation were most probably affected by distance from source and physical conditions of the environment (e.g., water current and mixing).

  7. New routes to synthesizing an ordered perovskite CaCu3Fe2Sb2O12 and its magnetic structure by neutron powder diffraction.

    PubMed

    Larregola, Sebastian A; Zhou, Jianshi; Alonso, Jose A; Pomjakushin, Vladimir; Goodenough, John B

    2014-05-01

    The search for new double-perovskite oxides has grown rapidly in recent years because of their interesting physical properties like ferroelectricity, magnetism, and multiferroics. The synthesis of double perovskites, especially the A-site-ordered perovskites, in most cases needs to be made under high pressure, which is a drawback for applying these materials. Here we have demonstrated synthetic routes at ambient pressure by which we have obtained a high-quality duo-sites-ordered double perovskite, CaCu3Fe2Sb2O12, which has been previously synthesized under high pressure. The availability of a large quantity of the powder sample allows us to determine the crystal and magnetic structures by neutron powder diffraction (NPD) at 300 and 1.3 K. Measurements of the magnetization and heat capacity showed a ferrimagnetic transition at 160 K. A ferrimagnetic structure consisting of the uncompensated antiferromagnetic coupling between neighboring collinear copper and iron spins has been resolved from the low-temperature NPD data. PMID:24716725

  8. Optimization of Ultrasound-Assisted Extraction of Cr, Cu, Zn, Cd, and Pb from Sediment, Followed by FAAS and GFAAS Analysis.

    PubMed

    Mimura, Aparecida M S; Oliveira, Marcone A L; Ciminelli, Virginia S T; Silva, Julio C J

    2016-01-01

    An ultrasound method for simultaneous extraction of Cr, Cu, Zn, Cd, and Pb from sediment, and determination by flame atomic absorption spectrometry (FAAS) and graphite furnace atomic absorption spectrometry (GFAAS) was proposed. The experimental results obtained using analytical curves and the method of standard additions agreed at a confidence level of 95% for all the analytes, as determined by FAAS and GFAAS, indicating no significant matrix effects. Recoveries ranged from 80.1 to 93.7% (certified reference material) and from 89 to 107% (spike tests). The LOD and LOQ results from the method were consistent with the techniques used (FAAS and GFAAS), with high analytical throughput. The proposed method was then used to determine Cr, Cu, Zn, Cd, and Pb in river sediment samples from Rio Doce, Minas Gerais, Brazil. The results indicated levels below those permitted by Brazilian legislation for all the analytes, with the exception of Cr. PMID:26851077

  9. Evaluation of the effectiveness of phosphate treatment for the remediation of mine waste soils contaminated with Cd, Cu, Pb, and Zn.

    PubMed

    Mignardi, Silvano; Corami, Alessia; Ferrini, Vincenzo

    2012-01-01

    The effectiveness of phosphate treatment for Cd, Cu, Pb, and Zn immobilization in mine waste soils was examined using batch conditions. Application of synthetic hydroxyapatite (HA) and natural phosphate rock (FAP) effectively reduced the heavy metal water solubility generally by about 84-99%. The results showed that HA was slightly superior to FAP for immobilizing heavy metals. The possible mechanisms for heavy metal immobilization in the soil involve both surface complexation of the metal ions on the phosphate grains and partial dissolution of the phosphate amendments and precipitation of heavy metal-containing phosphates. HA and FAP could significantly reduce Cd, Cu, Pb, and Zn availability in terms of water solubility in contaminated soils while minimizing soil acidification and potential risk of eutrophication associated with the application of highly soluble phosphate sources. PMID:22024096

  10. Distribution and speciation of metals (Cu, Zn, Cd, and Pb) in agricultural and non-agricultural soils near a stream upriver from the Pearl River, China.

    PubMed

    Yang, Silin; Zhou, Dequn; Yu, Huayong; Wei, Rong; Pan, Bo

    2013-06-01

    The distribution and chemical speciation of typical metals (Cu, Zn, Cd and Pb) in agricultural and non-agricultural soils were investigated in the area of Nanpan River, upstream of the Pearl River. The investigated four metals showed higher concentrations in agricultural soils than in non-agricultural soils, and the site located in factory district contained metals much higher than the other sampling sites. These observations suggested that human activities, such as water irrigation, fertilizer and pesticide applications might have a major impact on the distribution of metals. Metal speciation analysis presented that Cu, Zn and Cd were dominated by the residual fraction, while Pb was dominated by the reducible fraction. Because of the low mobility of the metals in the investigated area, no remarkable difference could be observed between upstream and downstream separated by the factory site. PMID:23466733

  11. Hydrothermal synthesis and structural characterization of an organic–inorganic hybrid sandwich-type tungstoantimonate [Cu(en){sub 2}(H{sub 2}O)]{sub 4}[Cu(en){sub 2}(H{sub 2}O){sub 2}][Cu{sub 2}Na{sub 4}(α-SbW{sub 9}O{sub 33}){sub 2}]·6H{sub 2}O

    SciTech Connect

    Liu, Yingjie; Cao, Jing; Wang, Yujie; Li, Yanzhou; Zhao, Junwei; Chen, Lijuan; Ma, Pengtao; Niu, Jingyang

    2014-01-15

    An organic–inorganic hybrid sandwich-type tungstoantimonate [Cu(en){sub 2}(H{sub 2}O)]{sub 4}[Cu(en){sub 2}(H{sub 2}O){sub 2}][Cu{sub 2}Na{sub 4}(α-SbW{sub 9}O{sub 33}){sub 2}]·6H{sub 2}O (1) has been synthesized by reaction of Sb{sub 2}O{sub 3}, Na{sub 2}WO{sub 4}·2H{sub 2}O, CuCl{sub 2}·2H{sub 2}O with en (en=ethanediamine) under hydrothermal conditions and structurally characterized by elemental analysis, inductively coupled plasma atomic emission spectrometry, IR spectrum and single-crystal X-ray diffraction. 1 displays a centric dimeric structure formed by two equivalent trivacant Keggin [α-SbW{sub 9}O{sub 33}]{sup 9−} subunits sandwiching a hexagonal (Cu{sub 2}Na{sub 4}) cluster. Moreover, those related hexagonal hexa-metal cluster sandwiched tungstoantimonates have been also summarized and compared. The variable-temperature magnetic measurements of 1 exhibit the weak ferromagnetic exchange interactions within the hexagonal (Cu{sub 2}Na{sub 4}) cluster mediated by the oxygen bridges. - Graphical abstract: An organic–inorganic hybrid (Cu{sub 2}Na{sub 4}) sandwiched tungstoantimonate [Cu(en){sub 2}(H{sub 2}O)]{sub 4}[Cu (en){sub 2}(H{sub 2}O){sub 2}][Cu{sub 2}Na{sub 4}(α-SbW{sub 9}O{sub 33}){sub 2}]·6H{sub 2}O was synthesized and magnetic properties was investigated. Display Omitted - Highlights: • Organic–inorganic hybrid sandwich-type tungstoantimonate. • (Cu{sub 2}Na{sub 4} sandwiched) tungstoantimonate [Cu{sub 2}Na{sub 4}(α-SbW{sub 9}O{sub 33}){sub 2}]{sup 10−}. • Ferromagnetic tungstoantimonate.

  12. Speciation of Pb, Cu and Zn determined by sequential extraction for identification of air pollution sources in Syria

    NASA Astrophysics Data System (ADS)

    Al-Masri, M. S.; Al-Kharfan, K.; Al-Shamali, K.

    Speciation of three trace elements (Zn, Pb, Cu) in air particulates of two Syrian cities (Tartous and Darya) with different climate conditions and industrial emissions has been studied. Air filters were collected during 2000-2001 and extracted chemically using different selective fluids in an attempt to identify the different forms of trace elements. Approximately 60% of lead in air particulates of both cities was found to be associated with organic materials produced by incomplete burning of vehicles fuels and residential heating; the remaining 40% of lead was as lead oxides and mineral acids soluble compounds. Zinc was found in oxides (28-65%) samples collected in Tartous city, indicating that the Tartous cement factory and phosphate loading cargoes are the main source of emissions. In the Darya filters, zinc associated with organic materials (28-49%) was related to the presence of plastic molding industries and corroding car tires. In addition, copper was also found to be in the form of oxides (19-46%) in both cities in the summer periods, while 13-25% and 35% are associated with organic materials and silicates, respectively. Differences in chemical forms of the studied trace elements in air particulates were found to be related to differences in air pollution sources and differences in human behaviour throughout the year. Therefore, chemical fractionation of trace elements in air particulates using sequential leaching can be used for identification of air pollutions sources in urban and industrial areas.

  13. Risk assessment for Cd, Cu, Pb and Zn in urban soils: chemical availability as the central concept.

    PubMed

    Rodrigues, S M; Cruz, N; Coelho, C; Henriques, B; Carvalho, L; Duarte, A C; Pereira, E; Römkens, Paul F A M

    2013-12-01

    To assess the geochemical reactivity and oral bioaccessibility of Cd, Cu, Pb and Zn in urban soils from the Porto area, four extractions were performed including Aqua Regia (AR; pseudototal), 0.43 M HNO3 (reactive), 0.01 M CaCl2 (available), and 0.4 M glycine at pH = 1.5, SBET method (oral bioaccessible pool). Oral bioaccessibility in urban soils was higher than in samples from rural, industrial and mining areas which is most likely related to sources of metals and parent materials of corresponding soils. The availability and reactivity were described well by non-linear Freundlich-type equations when considering differences in soil properties. The resulting empirical models are able to predict availability and reactivity and can be used to improve the accuracy of risk assessment. Furthermore, a close 1:1 relationship exists between results from the 0.43 M HNO3 method and the SBET method which substantially facilitates risk assessment procedures and reduces analytical costs. PMID:23194645

  14. Immobilization of heavy metals (Pb, Cu, Cr, Zn, Cd, Mn) in the mineral additions containing concrete composites.

    PubMed

    Giergiczny, Zbigniew; Król, Anna

    2008-12-30

    The presented work determines the level of heavy metals (Pb+2, Cu+2, Zn+2, Cr+6, Cd+2, Mn+2) immobilization in the composites produced using Ordinary Portland Cement (OPC) as well as of binders containing large amount of mineral additives in its composition-siliceous fly ash (FA), fluidized bed combustion ash (FFA) and ground granulated blast furnace slag (GGBFS). Heavy metals were introduced to cementitious materials in the form of soluble salts as well as components of hazardous wastes (medical ash, metallurgical dust). It has been stated, that the level of heavy metals immobilization is combined with composites composition. Majority of analyzed heavy metals, added to binders' composition in the form of heavy metal salts achieves high level of immobilization, in mortar based on binder with 85% GGBFS and 15% OPC. The lowest immobilization level was reached for chromium Cr+6 added to hardening mortars as Na2Cr2O72H2O. The level ranges from 85.97% in mortars made on blended binder (20% OPC, 30% FFA and 50% GGBFS) to 93.33% in mortar produced on OPC. The increase of the so-called immobilization degree with time of hardened material maturing was found. This should be attributed to the pozzolanic or pozzolanic/hydraulic properties of components used; their effect on microstructure of hardened material is also important. Mineral additions enter the hydration reactions in the mixtures and favor the formation of specific microstructure promoting the immobilization of hazardous elements. PMID:18423859

  15. Alginate and Algal-Based Beads for the Sorption of Metal Cations: Cu(II) and Pb(II).

    PubMed

    Wang, Shengye; Vincent, Thierry; Faur, Catherine; Guibal, Eric

    2016-01-01

    Alginate and algal-biomass (Laminaria digitata) beads were prepared by homogeneous Ca ionotropic gelation. In addition, glutaraldehyde-crosslinked poly (ethyleneimine) (PEI) was incorporated into algal beads. The three sorbents were characterized by scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX): the sorption occurs in the whole mass of the sorbents. Sorption experiments were conducted to evaluate the impact of pH, sorption isotherms, and uptake kinetics. A special attention was paid to the effect of drying (air-drying vs. freeze-drying) on the mass transfer properties. For alginate, freeze drying is required for maintaining the porosity of the hydrogel, while for algal-based sorbents the swelling of the material minimizes the impact of the drying procedure. The maximum sorption capacities observed from experiments were 415, 296 and 218 mg Pb g(-1) and 112, 77 and 67 mg Cu g(-1) for alginate, algal and algal/PEI beads respectively. Though the sorption capacities of algal-beads decreased slightly (compared to alginate beads), the greener and cheaper one-pot synthesis of algal beads makes this sorbent more competitive for environmental applications. PEI in algal beads decreases the sorption properties in the case of the sorption of metal cations under selected experimental conditions. PMID:27598128

  16. Contamination by Cd, Cu, Pb, and Zn in mine wastes from abandoned metal mines classified as mineralization types in Korea.

    PubMed

    Jung, Myung Chae

    2008-06-01

    The objective of this study was to investigate heavy metal contamination and geochemical characteristics of mine wastes, including tailings, from 38 abandoned mines classified as five mineralization types. Mine waste materials including tailings and soils were sampled from the mines and the physical and chemical characteristics of the samples were analyzed. The particle size of tailings was in the range of 10-100 microm. The pH of the waste covered a wide range, from 1.73 to 8.11, and was influenced by associated minerals and elevated levels of Cd, Cu, Pb, and Zn, extracted by a Korean Standard Method (digestion with 0.1 mol L(-1) HCl), which were found in the wastes. Half of the samples contained heavy metals at levels above those stipulated by the Soil Environmental Conservation Act (SECA) in Korea. In addition, extremely high concentrations of the metals were also found in mine wastes extracted by aqua regia, especially those from mines associated with sulfide minerals. Thus, it can be expected that trace elements in mine wastes may be dispersed both downstream and downslope through water and wind. Eventually they may pose a potential health risk to residents in the vicinity of the mine. It is necessary to control mine wastes by using a proper method for their reclamation, such as neutralization of the mine wastes using a fine-grained limestone. PMID:17687627

  17. Simultaneous determination of Cu 2+, Zn 2+, Cd 2+, Hg 2+ and Pb 2+ by using second-derivative spectrophotometry method

    NASA Astrophysics Data System (ADS)

    Han, Yanyan; Li, Yan; Si, Wei; Wei, Dong; Yao, Zhenxing; Zheng, Xianpeng; Du, Bin; Wei, Qin

    2011-09-01

    A new method of simultaneous determination of Cu 2+, Zn 2+, Cd 2+, Hg 2+ and Pb 2+ is proposed here by using the second-derivative spectrophotometry method. In pH = 10.35 Borax-NaOH buffer, using meso-tetra (3-methoxyl-4-hydroxylphenyl) porphyrin ([T-(3-MO-4-HP)P]) as chromomeric reagent, micelle solution was formed after Tween-80 surfactant was added into the solution containing Cu 2+, Zn 2+, Cd 2+, Hg 2+ and Pb 2+ ions. The original absorption spectrum of the above complexes was obtained after heating in the boiling water for 25 min. The second-derivative absorption peaks of five metal-porphyrin complexes can be separated from the original absorption spectrum by using chemometric tool. In this way, Cu 2+, Zn 2+, Cd 2+, Hg 2+ and Pb 2+ ions can be determined simultaneously. Under the optimal conditions, the linear ranges of the calibration curve were 0-0.60, 0-0.60, 0-0.40, 0-0.80 and 0-0.48 μg mL -1 for Cu 2+, Zn 2+, Cd 2+, Hg 2+ and Pb 2+, respectively. The molar absorptivity of these color systems were 1.38 × 10 5, 1.01 × 10 5, 3.24 × 10 5, 1.07 × 10 5 and 1.29 × 10 5 L mol -1 cm -1. The method developed in this paper has advantages in selectivity, sensitivity, operation and can effectively resolve spectra overlapping problem. This method has been applied to determine the real samples with satisfactory results.

  18. Preparation of Bi-Pb-Sr-Ca-Cu-O oxide superconductors by coprecipitation of nanosize oxalate precursor powders in the aqueous core of water-in-oil microemulsions

    NASA Astrophysics Data System (ADS)

    Kumar, P.; Pillai, V.; Shah, D. O.

    1993-02-01

    We describe a new technique for the synthesis of ultrahomogeneous nanoparticles of precursor oxalate powder by coprecipitation in the aqueous core of a water-in-oil microemulsion for the preparation of Bi-Pb-Sr-Ca-Cu-O (2223) oxide superconductor. This process ensures a uniform mixing of metal cations down to a scale of at least 10 nm. This finely dispersed precursor powder results in phase pure (2223) oxide superconductor after proper heat treatment.

  19. Fast emulsion-based method for simultaneous determination of Co, Cu, Pb and Se in crude oil, gasoline and diesel by graphite furnace atomic absorption spectrometry.

    PubMed

    Luz, Maciel S; Nascimento, Angerson N; Oliveira, Pedro V

    2013-10-15

    A method for the simultaneous determination of Co, Cu, Pb and Se in crude oil, gasoline and diesel samples using emulsion-based sampling and GF AAS is proposed. 400mg of sample was weighted in volumetric flask following the sequential addition of 125 µL of hexane and 7.5 mL of Triton X-100(®) (20% mv(-1)). Subsequently, the mixture was stirred in ultrasonic bath, during 30 min, before dilution to 25 mL with deionized water. Aliquots of 20 μL of reference solution or sample emulsion were co-injected into the graphite tube with 10 μL of 2 g L(-1) Pd(NO3)2. The pyrolysis and atomization temperatures were 1300°C and 2250°C, respectively. The limits of detection (n=10, 3σ) and characteristic masses were 0.02 μg g(-1) (0.32 μg L(-1)) and 18 pg for Co, 0.03 μg g(-1) (0.48 μg L(-1)) and 15 pg for Cu, 0.04 μg g(-1) (0.64 μg L(-1)) and 48 pg for Pb, and 0.11 μg g(-1) (1.76 μg L(-1)) and 47 pg for Se. The reliabilities of the proposed method for Co and Se were checked by SRM(®) 1634c Residual Oil analysis. The found values are in accordance to the SRM at 95% confidence level (Student's t-test). Each sample was spiked with 0.18 μg g(-1) of Co, Cu, Pb and Se and the recoveries varied from 92% to 116% for Co, 83% to 117% for Cu, 72% to 117% for Pb, and 82% to 122% for Se. PMID:24054610

  20. Determination of Cu(2+), Zn(2+) and Pb(2+) in biological and food samples by FAAS after preconcentration with hydroxyapatite nanorods originated from eggshell.

    PubMed

    Mortada, Wael I; Kenawy, Ibrahim M M; Abdelghany, Amr M; Ismail, Amani M; Donia, Ahmed F; Nabieh, Kareem A

    2015-01-01

    Hydroxyapatite nanorods (HAPNRs) were prepared from recycled eggshell by using precipitation method. The structure of the HAPNRs was physicochemically and morphologically characterized by X-ray diffraction, transmission electron microscopy and Fourier transform infrared spectroscopy. The resulting HAPNRs were used for solid phase extractive preconcentration of Cu(2+), Zn(2+) and Pb(2+) prior to its determination by flame atomic absorption spectrometry. Experimental variables that influence the quantitative extraction of metal ions were optimized by both batch and column methods. The analytes were quantitatively sorbed on the matrix between pHs6 and 9. The maximum sorption capacity of the HAPNRs has been found to be 2.43, 2.37 and 2.53 mmol g(-1) for Cu(2+), Zn(2+) and Pb(2+), respectively, with the preconcentration factor of 250. The 3σ detection limit and 10σ quantification limit for Cu(2+), Zn(2+) and Pb(2+) were found to be 0.72, 0.55 and 5.12 μg L(-1) and 2.40, 1.83 and 17.06 μg L(-1), respectively. The calibration curves were linear up to 250 μg L(-1) for Cu(2+), 300 μg L(-1) for Zn(2+) and 400 μg L(-1) for Pb(2+). Accuracy of the proposed method was verified using certified reference materials (NCS ZC85006 Tomato, Seronorm Trace Elements Whole Blood L-1, Seronorm Trace Elements Whole Blood L-3 and Seronorm Trace Elements Urine). The present method was successfully applied to the analysis of these metal ions in sea water, biological and food samples. PMID:25953570

  1. Removal of Co(II), Cu(II) and Pb(II) ions by polymer based 2-hydroxyethyl methacrylate: thermodynamics and desorption studies

    PubMed Central

    2012-01-01

    Removal thermodynamics and desorption studies of some heavy metal ions such as Co(II), Cu(II) and Pb(II) by polymeric surfaces such as poly 2-hydroxyethyl methacrylate (PHEMA) and copolymer 2-hydroxyethyl methacrylate with monomer methyl methacrylate P(MMA-HEMA) as adsorbent surfaces from aqueous single solution were investigated with respect to the changes in pH of solution, adsorbent composition, contact time and temperature in the individual aqueous solution. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained and the results revealed that the Langmuir isotherm fitted the experiment results better than Freundlich isotherm. Using the Langmuir model equation, the monolayer removal capacity of PHEMA surface was found to be 0.7388, 0.8396 and 3.0367 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions and removal capacity of P(MMA-HEMA) was found to be 28.8442, 31.1526 and 31.4465 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions, respectively. Changes in the standard Gibbs free energy (ΔG0), standard enthalpy (ΔH0) and standard entropy (ΔS0) showed that the removals of mentioned ions onto PHEMA and P(MMA-HEMA) are spontaneous and exothermic at 293–323 K. The maximum desorption efficiency was 75.26% for Pb(II) using 0.100 M HNO3, 70.10% for Cu(II) using 0.100 M HCl, 59.20% for 0.100 M HCl 63.67% Co(II). PMID:23369255

  2. Inclusive spectra of protons emitted in interactions between /sup 3/He nuclei of energy 4. 9 GeV per nucleon and C, Cu, and Pb nuclei

    SciTech Connect

    Ad'yasevich, B.P.; Antonenko, V.G.; Vinogradov, A.A.; Grigor'yan, Y.I.; Ippolitov, M.S.; Karadzhev, K.V.; Lebedev, A.L.; Man'ko, V.I.; Nikolaev, S.A.; Polunin, Y.P.; and others

    1987-02-01

    We have measured inclusive spectra of protons emitted in interactions between /sup 3/He nuclei of energy 4.9 GeV per nucleon and C, Cu, and Pb nuclei. Data are presented on the invariant cross sections for proton yield in the range of emission angles from 20/sup 0/ to 150/sup 0/ for the momentum interval 350--850 MeV/c. The data obtained are analyzed.

  3. Predicting the mobility of Zn, Fe, Cu, Pb, Cd from roasted sulfide (pyrite) residues -- A case study of wastes from the sulfuric acid industry in Sweden

    SciTech Connect

    Lin, Z.; Qvarfort, U.

    1996-12-31

    Leachates from roasted sulfide residues, which are the wastes from the production of sulfuric acid at Falun, Sweden, have low pH and high concentrations of Zn, Fe, and SO{sub 4}. The minerals are mainly hematite and maghemite and, because the various sulfides in the feed behave differently during the roasting process, the residual sulfides minerals are pyrrhotite and sphalerite. Oxidation of the residual sulfides contributes acidity, Zn, Fe, Cu, Cd, and sulfate to the effluents from the waste deposits. The dissolution of sphalerite is most likely accelerated in acid solution rich in Fe(III). The formation of Pb-sulfate coatings on galena may provide an armoring effect which slows the oxidation of the galena. Residual sulfides are source phases controlling long-term contaminant release. Other source minerals for Zn, Fe, Pb, Cu, Cd and SO{sub 4} in the effluents are iron oxides which retained percentage quantities of SO{sub 4}, roast-derived alteration rims of Zn oxides on sphalerite, altered silicates formed during the roasting process, and secondary minerals (e.g., Zn, Fe, Cu sulfates, iron hydroxides) that were precipitated by in-site oxidation in the waste dumps. The Zn, Fe, and Cu sulfates most likely control short-term changes in the chemistry of the leachate, while Pb concentration in the leachates may be controlled predominantly by Pb-release from the altered silicates. The mineralogical and geochemical data provide fundamental information essential for the remedial management of this type of industrial waste.

  4. Simultaneous determination of Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ by using second-derivative spectrophotometry method.

    PubMed

    Han, Yanyan; Li, Yan; Si, Wei; Wei, Dong; Yao, Zhenxing; Zheng, Xianpeng; Du, Bin; Wei, Qin

    2011-09-01

    A new method of simultaneous determination of Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ is proposed here by using the second-derivative spectrophotometry method. In pH=10.35 Borax-NaOH buffer, using meso-tetra (3-methoxyl-4-hydroxylphenyl) porphyrin ([T-(3-MO-4-HP)P]) as chromomeric reagent, micelle solution was formed after Tween-80 surfactant was added into the solution containing Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ ions. The original absorption spectrum of the above complexes was obtained after heating in the boiling water for 25 min. The second-derivative absorption peaks of five metal-porphyrin complexes can be separated from the original absorption spectrum by using chemometric tool. In this way, Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ ions can be determined simultaneously. Under the optimal conditions, the linear ranges of the calibration curve were 0-0.60, 0-0.60, 0-0.40, 0-0.80 and 0-0.48 μg mL(-1) for Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+, respectively. The molar absorptivity of these color systems were 1.38×10(5), 1.01×10(5), 3.24×10(5), 1.07×10(5) and 1.29×10(5)Lmol(-1)cm(-1). The method developed in this paper has advantages in selectivity, sensitivity, operation and can effectively resolve spectra overlapping problem. This method has been applied to determine the real samples with satisfactory results. PMID:21664176

  5. Accumulation of Al, Mn, Fe, Cu, Zn, Cd and Pb by the bryophyte Scapania undulata in three upland waters of different pH.

    PubMed

    Vincent, C D; Lawlor, A J; Tipping, E

    2001-01-01

    Measurements were made of the contents of Al, Mn, Fe, Cu, Zn, Cd and Pb in Scapania undulata in three streams (D2, D5, D11) in the English Lake District. The stream waters had average pH values of 5.35 (D2), 5.81 (D5) and 7.26 (D11), the main differences in other major chemical components being in Mg, Al, Ca and alkalinity. There was generally more metal accumulation in the older parts of the plants, but this was not significant in all cases. Extents of accumulation varied with stream pH and dissolved metal concentration. For Al, accumulation was greatest in streams D2 and D5. Mn accumulated most in D5 and Fe was without preference. Cu, Zn and Cd accumulated mostly in the plants in stream D11 and Pb accumulated more in D5 and D11. In terms of enrichment factors (amount of metal in the plants divided by stream water concentration) the sequence was Zn < Cd < Cu < Mn < Pb < Al < Fe. Laboratory experiments supported the findings of the field data, providing evidence that uptake increases with pH at constant total metal concentration. The results are interpreted qualitatively in terms of the chemical speciation of the metals in the stream water and competition between metal ions and protons at the plant-water interface. It is suggested that Al, Cu, Zn, Cd and Pb behave according to chemical complexation, whereas redox processes and/or colloidal interactions may be significant for Mn and Fe. PMID:11444010

  6. Intrinsic Josephson properties in Pb1-ySr2Y1-xCaxCu2+yO7+δ epitaxial films

    NASA Astrophysics Data System (ADS)

    Komori, Sachio; Kakeya, Itsuhiro

    2014-12-01

    We report the first observation of intrinsic Josephson junction (IJJ) characteristics in the Pb1-ySr2Y1-xCaxCu2+yO7+δ (Pb1212) epitaxial film. Pb1212 epitaxial film has been grown on SrTiO3 (100) substrates by a two-step growth technique. A small mesa structure (S = 4μm2) has been fabricated on a film surface using a standard photolithography and an Ar ion milling technique. The superconducting transition temperature of the IJJ is 43 K. At 4.2 K, the value of Jc (the critical current density) is 2.2 kA/cm2. The depth of the hysteresis defined as α = (Jc+Jr)/ Jc is 0.89, where Jr is the return current density. The temperature dependence of Jc shows good agreement with Ambegaokar-Baratoff theory.

  7. Measurement of the mass attenuation coefficients and electron densities for BiPbSrCaCuO superconductor at different energies

    NASA Astrophysics Data System (ADS)

    Çevik, U.; Baltaş, H.

    2007-03-01

    The mass attenuation coefficients for Bi, Pb, Sr, Ca, Cu metals, Bi2O3, PbO, SrCO3, CaO, CuO compounds and solid-state forms of Bi1.7Pb0.3Sr2Ca2Cu3O10 superconductor were determined at 57.5, 65.2, 77.1, 87.3, 94.6, 122 and 136 keV energies. The samples were irradiated using a 57Co point source emitted 122 and 136 keV γ-ray energies. The X-ray energies were obtained using secondary targets such as Ta, Bi2O3 and (CH3COO)2UO22H2O. The γ- and X-rays were counted by a Si(Li) detector with a resolution of 0.16 keV at 5.9 keV. The effect of absorption edges on electron density, effective atomic numbers and their variation with photon energy in composite superconductor samples was discussed. Obtained values were compared with theoretical values.

  8. Biosorption of Cu(II), Zn(II), Ni(II) and Pb(II) ions by cross-linked metal-imprinted chitosans with epichlorohydrin.

    PubMed

    Chen, Chia-Yun; Yang, Cheng-Yu; Chen, Arh-Hwang

    2011-03-01

    Cross-linked metal-imprinted chitosan microparticles were prepared from chitosan, using four metals (Cu(II), Zn(II), Ni(II), and Pb(II)) as templates, and epichlorohydrin as the cross-linker. The microparticles were characterized by Fourier transform infrared spectroscopy, solid state (13)C nuclear magnetic resonance spectroscopy, and energy-dispersive X-ray spectroscopy. They were used for comparative biosorption of Cu(II), Zn(II), Ni(II) and Pb(II) ions in an aqueous solution. The results showed that the sorption capacities of Cu(II), Zn(II), Ni(II), and Pb(II) on the templated microparticles increased from 25 to 74%, 13 to 46%, 41 to 57%, and 12 to 43%, respectively, as compared to the microparticles without metal ion templates. The dynamic study showed that the sorption process followed the second-order kinetic equation. Three sorption models, Langmuir, Freundlich, and Dubinin-Radushkevich, were applied to the equilibrium isotherm data. The result showed that the Langmuir isotherm equation best fitted for monolayer sorption processes. Furthermore, the microparticles can be regenerated and reused for the metal removal. PMID:21044814

  9. Cd, Cr, Cu, Pb, and Zn concentrations in Ulva lactuca, Codium fragile, Jania rubens, and Dictyota dichotoma from Rabta Bay, Jijel (Algeria).

    PubMed

    Laib, Essaid; Leghouchi, Essaid

    2012-03-01

    Concentrations of Cd, Cr, Cu, Pb, and Zn were determined in algae samples collected from the Rabta Bay in the Mediterranean Sea, Algeria. The levels of heavy metals in the macroalgae, Ulva lactuca, Codium fragile (green algae), Jania rubens (red algae), and Dictyota dichotoma (brown algae) recorded high concentrations except for Cd. Moreover, Zn was the most predominant metal in the seaweeds. The obtained HM contents indicate that different species demonstrate various degree of metal accumulation and the obtained higher values in site 1 of the studied zone can be attributed to the discharge influence of two rivers (Mouttas and Larayeche Rivers), entering the Mediterranean Sea and local pollutant emissions. The abundance of heavy metal concentrations in the macroalgae samples was found in the order below: Zn > Cu > Pb > Cr > Cd from the studied zone. The highest amounts of heavy metals in algae samples were Cd, Cu, and Pb in brown algae, and Cr and Zn in green and brown algae from the studied zone (Rabta Bay). PMID:21755430

  10. Biochar prepared from castor oil cake at different temperatures: A voltammetric study applied for Pb(2+), Cd(2+) and Cu(2+) ions preconcentration.

    PubMed

    Kalinke, Cristiane; Mangrich, Antonio Sálvio; Marcolino-Junior, Luiz H; Bergamini, Márcio F

    2016-11-15

    Biochar is a carbonaceous material similar produced by pyrolysis of biomass under oxygen-limited conditions. Pyrolysis temperature is an important parameter that can alters biochar characteristics (e.g. surface area, pore size distribution and surface functional groups) and affects it efficacy for adsorption of several probes. In this work, biochar samples have been prepared from castor oil cake using different temperatures of pyrolysis (200-600°C). For the first time, a voltammetric procedure based on carbon paste modified electrode (CPME) was used to investigate the effect of temperature of pyrolysis on the adsorptive characteristics of biochar for Pb(II), Cd(II) and Cu(II) ions. Besides the electrochemical techniques, several characterizations have been performed to evaluate the physicochemical properties of biochar in function of the increase of the pyrolysis temperature. Results suggest that biochar pyrolized at 400°C (BC400) showed a better potential for ions adsorption. The CPME modified with BC400 showed better relative current signal with adsorption affinity: Pb(II)>Cd(II)>Cu(II). Kinetic studies revealed that the pseudo-second order model describes more accurately the adsorption process suggesting that the surface reactions control the adsorption rate. Values found for amount adsorbed were 15.94±0.09; 4.29±0.13 and 2.38±0.39μgg(-1) for Pb(II), Cd(II) and Cu(II) ions, respectively. PMID:27469040

  11. Fe(III) hydroxide nucleation and growth on quartz in the presence of Cu(II), Pb(II), and Cr(III): metal hydrolysis and adsorption.

    PubMed

    Dai, Chong; Hu, Yandi

    2015-01-01

    Fe(III) hydroxide nanoparticles are an essential carrier for aqueous heavy metals. Particularly, iron hydroxide precipitation on mineral surfaces can immobilize aqueous heavy metals. Here, we used grazing-incidence small-angle X-ray scattering (GISAXS) to quantify nucleation and growth of iron hydroxide on quartz in 0.1 mM Fe(NO3)3 solution in the presence of Na(+), Cu(2+), Pb(2+), or Cr(3+) at pH = 3.7 ± 0.1. In 30 min, the average radii of gyration (R(g)) of particles on quartz grew from around 2 to 6 nm in the presence of Na(+) and Cu(2+). Interestingly, the particle sizes remained 3.3 ± 0.3 nm in the presence of Pb(2+), and few particles formed in the presence of Cr(3+). Quartz crystal microbalance dissipation (QCM-D) measurements showed that only Cr(3+) adsorbed onto quartz, while Cu(2+) and Pb(2+) did not. Cr(3+) adsorption changed the surface charge of quartz from negative to positive, thus inhibiting the precipitation of positively charged iron hydroxide on quartz. Masses and compositions of the precipitates were also quantified. This study provided new insights on interactions among quartz, iron hydroxide, and metal ions. Such information is helpful not only for environmental remediation but also for the doping design of iron oxide catalysts. PMID:25496643

  12. Solid-phase extraction of Cu, Co and Pb on oxidized single-walled carbon nanotubes and their determination by inductively coupled plasma mass spectrometry.

    PubMed

    Chen, Shizhong; Liu, Cheng; Yang, Ming; Lu, Dengbo; Zhu, Li; Wang, Zhan

    2009-10-15

    A novel method using a microcolumn packed with single-walled carbon nanotubes (SWNTs) as a new adsorption material was developed for the preconcentration of trace Cu, Co and Pb in biological and environmental samples prior to their determination by inductively coupled plasma mass spectrometry (ICP-MS). SWNTs oxidized with concentrated nitric acid have been proved to possess an exceptional adsorption capability for the analytes due to their surface functionalization. The adsorption behaviors of the analytes on SWNTs under dynamic conditions were studied systematically. The main factors influencing the preconcentration and determination of the analytes (pH, sample flow rate and volume, eluent concentration and interfering ions) have been examined in detail. Under the optimum conditions, the detection limits for Cu, Co and Pb were 39, 1.2 and 5.4 pg mL(-1), respectively; the relative standard deviations (RSDs) were found to be less than 6.0% (n=9, c=1.0 ng mL(-1)). This method was validated using a certified reference material of mussel, and has been successfully applied for the determination of trace Cu, Co and Pb in real water sample with the recoveries of 96.0-109%. PMID:19473762

  13. Ligand-modified polyelectrolyte-enhanced ultrafiltration with electrostatic attachment of ligands. 1. Removal of Cu(II) and Pb(II) with expulsion of Ca(II)

    SciTech Connect

    Tuncay, M. Univ. of Oklahoma, Norman, OK ); Christian, S.D.; Tucker, E.E.; Taylor, R.W.; Scamehorn, J.F. )

    1994-12-01

    A water-soluble mixture of a cationic polyelectrolyte, poly(diallyldimethylammonium chloride) or PDADMAC, and an anionic ligand, 4,5-dihydroxy-1,3-benzenedisulfonic acid, or Tiron, is used as an agent for binding divalent cations, such as Cu[sup 2+] and Pb[sup 2+]. In equilibrium dialysis experiments, the PDADMAC-Tiron mixture is shown to be effective in binding Cu[sup 2+] and Pb[sup 2+] in the retentate, while enhancing the concentration of the noncomplexed cation, Ca[sup 2+], in the permeate. In the pH range employed, the uncomplexed and complexed forms of Tiron exist primarily as divalent anions. As a consequence they are bound electrostatically to the cationic polyelectrolyte, and little of the ligand is lost through the membrane. The effects of pH, cation concentration, and presence of a competing cation (Ca[sup 2+]), and added NaCl on the retention of Cu[sup 2+] and Pb[sup 2+] are discussed. 25 refs., 4 figs., 2 tabs.

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

    PubMed

    Durán, Iria; Nieto, Oscar

    2011-09-30

    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. PMID:21872034

  15. The magnetic properties of R in Pb 2Sr 2(R/Ca)Cu 3O 8 (R = HO and Er)

    NASA Astrophysics Data System (ADS)

    Soderholm, L.; Loong, C.-K.; Staub, U.; Skanthakumar, S.; Simon Xue, J.; Hammonds, J. P.; Greedan, J. E.; Maric, M.

    1995-02-01

    The electronic behavior of the rare-earth ion (R) in the Pb based superconductors Pb 2Sr 2(R 1- xCa x)Cu 3O 8, for R = Er ( x = 0, 0.5) and Ho ( x = 0), has been analyzed by inelastic neutron scattering. Sharp, well-defined transitions of magnetic origin have been observed for the parent R = Er and Ho ( x = 0) compounds. Peaks, determined to be of magnetic origin, have been assigned to crystal-field (CF) transitions within the Russell-Saunders ground multiplet. These results have been modeled using a crystal-field hamiltonian that includes intermediate-coupling and spherical-tensor techniques. The CF potential was determined for tetragonal symmetry. The calculated parameters are similar to those determined for similar R in the RBa 2Cu 3O 7 compounds. The results of the crystal-field analyses for the parent compounds are used to calculate the expected rare-earth contributions to the magnetic susceptibility, and compared to experimental data where available. In contrast to the data on the parent compounds, the spectra obtained from the superconductor Pb 2Sr 2Er 0.5Ca 0.5Cu 3O 8 show only very broad features. This broadening is attributed to chemical disorder rather than to an electronic effect.

  16. Distribution, mobility, and pollution assessment of Cd, Cu, Ni, Pb, Zn, and Fe in intertidal surface sediments of Sg. Puloh mangrove estuary, Malaysia.

    PubMed

    Udechukwu, Bede Emeka; Ismail, Ahmad; Zulkifli, Syaizwan Zahmir; Omar, Hishamuddin

    2015-03-01

    Sungai Puloh mangrove estuary supports a large diversity of macrobenthic organisms and provides social benefits to the local community. Recently, it became a major recipient of heavy metals originating from industries in the hinterland as a result of industrialization and urbanization. This study was conducted to evaluate mobility and pollution status of heavy metals (Cd, Cu, Ni, Pb, Zn, and Fe) in intertidal surface sediments of this area. Surface sediment samples were collected based on four different anthropogenic sources. Metals concentrations were analyzed using an atomic absorption spectrophotometer (AAS). Results revealed that the mean concentrations were Zn (1023.68 ± 762.93 μg/g), Pb (78.8 ± 49.61 μg/g), Cu (46.89 ± 43.79 μg/g), Ni (35.54 ± 10.75 μg/g), Cd (0.94 ± 0.29 μg/g), and Fe (7.14 ± 0.94%). Most of the mean values of analyzed metals were below both the interim sediment quality guidelines (ISQG-low and ISQG-high), except for Pb concentration (above ISQG-low) and Zn concentration (above ISQG-high), thus suggesting that Pb and Zn may pose some environmental concern. Cadmium, Pb, and Zn concentrations were above the threshold effect level (TEL), indicating seldom adverse effect of these metals on macrobenthic organisms. Pollution load index (PLI) indicated deterioration and other indices revealed the intertidal surface sediment is moderately polluted with Cd, Pb, and Zn. Therefore, this mangrove area requires urgent attention to mitigate further contamination. Finally, this study will contribute to data sources for Malaysia in establishing her own ISQG since it is a baseline study with detailed contamination assessment indices for surface sediment of intertidal mangrove area. PMID:25292304

  17. Geological, fluid inclusion and isotopic studies of the Baiyangping Pb-Zn-Cu-Ag polymetallic deposit, Lanping basin, Yunnan province, China

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Hu; Hou, Zeng-Qian; Song, Yu-Cai; Zhang, Hong-Rui

    2015-11-01

    Baiyangping Pb-Zn-Cu-Ag deposit is located in Lanping basin, northwestern Yunnan province. The deposit is composed of a few ore veins and can be divided into several ore blocks. The ore bodies are primarily hosted in Mesozoic carbonate, sandstone and siltstone along the north-south-striking, NWW-striking and NE-SW-striking fault zones. There are breccia, massive, vein like and disseminated ores. The main ore minerals are sphalerite, galena, gratonite, jordanite, tetrahedrite series minerals, chalcocite, chalcopyrite, realgar, orpiment, bournonite, cobalt-bearing arsenopyrite, argentite, kongsbergite, cobaltine, siegenite. The sizes of fluid inclusions in Baiyangping deposit are generally less than 10 μm and have the shape of round, oval, irregular, etc. The ore-forming fluid system is Ca2+-Na+-K+-Mg2+-Cl--F--NO3- brine system. The freezing temperature of fluid inclusions in mineral deposits ranges from -26.4 to -0.2 °C, average -14.6 °C; the homogenization temperature is concentrated in 120-180 °C, and the salinity is between 0.35 and 24.73 wt% (NaCleq), average 16.9 wt% (NaCleq). δ13CPDB and δ18OSMOW values of hydrothermal calcite range from -4.16‰ to 3‰ and -2.5‰ to 20.4‰, respectively. δ34S values of sulfide minerals range from -10.2‰ to 11.2‰, average 5.6‰. The sulfide samples yield 206Pb/204Pb values of 18.609-18.818, 207Pb/204Pb of 15.548-15.842 and 208Pb/204Pb = 38.514-39.556. C-O-S-Pb isotope compositions of the Baiyangping deposit indicate a homogeneous carbon source, and the carbon in hydrothermal calcite is derived from the dissolution of carbonate rock strata, the ore-forming fluid belongs to basin brine fluid system, which is mixed with the precipitate water, sulfur in sulfides and sulfosalts is derived from thermal chemical sulfate reduction, and the thermal decomposition of sulfur-bearing organic matter. The metal mineralization material is from sedimentary strata and basement. The late Pb-Zn polymetallic mineralization event

  18. Analytical and quantitative concentration of gunshot residues (Pb, Sb, Ba) to estimate entrance hole and shooting-distance using confocal laser microscopy and inductively coupled plasma atomic emission spectrometer analysis: an experimental study.

    PubMed

    Turillazzi, Emanuela; Di Peri, Giovanni Paolo; Nieddu, Antonio; Bello, Stefania; Monaci, Fabrizio; Neri, Margherita; Pomara, Cristoforo; Rabozzi, Roberto; Riezzo, Irene; Fineschi, Vittorio

    2013-09-10

    The identification of gunshot residues (GSRs) on human body in firearm related fatalities may be essential for the evaluation of gunshot wounds and for the analysis of the shooting distance. The present study introduces the elemental analysis of the GSRs by inductively coupled plasma atomic emission spectrometer analysis (ICP-AES) performed on skin samples. ICP-AES was used to increase the accuracy of the analysis in gunshots fired from long and medium distance. In this experimental study, a series of 50 test shots have been performed in an open space with lateral wind protection. As target we used pig skin cut into 20 cm × 20 cm squares. The firing distances were 0.2, 5, 50, 100 and 150 cm. To exclude environmental contamination, each skin sample was carefully washed with deionized water and dried at room temperature in a closed box before the shooting test. We choose 9×21 and the 7.65 mm calibers handguns, loaded with different ammunitions. At ICP-AES analysis a clearly decreasing trend in the quantity and the concentration of the different elements of GSR by increasing the firing distance for both the guns used in the test was evident for every portion of skin samples analyzed. The analytical results obtained by ICP-AES confirmed very high concentrations of Pb, Sb, and Ba in the close-range shots and low concentrations of these particles in the intermediate and distant shots. In particular, the concentration of Sb, Ba, and Pb was significantly different from loose values when the firing distance was 100-150 cm for both the 9×21 and the 7.65 mm calibers. PMID:23890629

  19. Creep of polycrystalline (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}

    SciTech Connect

    Martinez-Fernandez, J.; Dominguez-Rodriguez, A.; Routbort, J.L.; Goretta, K.C.

    2000-04-14

    Plastic deformation has proved to be essential to the manufacture of bulk (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) superconductors. Compressive creep of dense, forged Bi-2223, Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} (Bi-2212), and Bi{sub 2}Sr{sub 2}CuO{sub x} (Bi-2201) superconductors has been studied. These previous studies left unanswered questions about the large variation in Q among the Bi-superconductors and the rate-controlling deformation mechanism. The goals of this work were to test high-quality bulk Bi-2223 to determine whether steady state can be established, and if so, to determine the dominant creep mechanism and the values of n and Q.

  20. Geochemical and Sr-Pb-Nd isotopic characteristics of the Shakhtama porphyry Mo-Cu system (Eastern Transbaikalia, Russia)

    NASA Astrophysics Data System (ADS)

    Berzina, A. P.; Berzina, A. N.; Gimon, V. O.

    2014-01-01

    The Shakhtama Mo-Cu porphyry deposit is located within the eastern segment of the Central Asian Orogenic Belt, bordering the southern margin of the Mongol-Okhotsk suture zone. The deposit includes rocks of two magmatic complexes: the precursor plutonic (J2) and ore-bearing porphyry (J3) complexes. The plutonic complex was emplaced at the final stages of the collisional regime in the region; the formation of the porphyry complex may have overlapped with a transition to extension. The Shakhtama rocks are predominantly metaluminous, I-type high K calc-alkaline to shoshonitic in composition, with relatively high Mg#, Ni, Cr and V. They are characterized by crustal-like ISr (0.70741-0.70782), relatively radiogenic Pb isotopic compositions, ɛNd(T) values close to CHUR (-2.7 to +2.1) and Nd model ages from 0.8 to 1.2 Ga. Both complexes are composed of rocks with K-adakitic features and rocks without adakite trace element signatures. The regional geological setting together with geochemical and isotopic data indicate that both juvenile and old continental crust contributed to their origin. High-Mg# K-adakitic Shakhtama magmas were most likely generated by partial melting of thickened lower crust during delamination and interaction with mantle material, while magmas lacking adakite-like signatures were probably generated at shallower levels of lower crust. The derivation of melts, related to the formation of plutonic and porphyry complexes involved variable amounts of old Precambrian lower crust and juvenile Phanerozoic crust. Isotopic data imply stronger contribution of juvenile mantle-derived material to the fertile magmas of the porphyry complex. Juvenile crust is proposed as an important source of fluids and metals for the Shakhtama ore-magmatic system.

  1. The transport behavior of As, Cu, Pb, and Zn during electrokinetic remediation of a contaminated soil using electrolyte conditioning.

    PubMed

    Yang, Jung-Seok; Kwon, Man Jae; Choi, Jaeyoung; Baek, Kitae; O'Loughlin, Edward J

    2014-12-01

    Electrokinetic remediation (also known as electrokinetics) is a promising technology for removing metals from fine-grained soils. However, few studies have been conducted regarding the transport behavior of multi-metals during electrokinetics. We investigated the transport of As, Cu, Pb, and Zn from soils during electrokinetics, the metal fractionation before and after electrokinetics, the relationships between metal transport and fractionation, and the effects of electrolyte conditioning. The main transport mechanisms of the metals were electroosmosis and electromigration during the first two weeks and electromigration during the following weeks. The direction of electroosmotic flow was from the anode to the cathode, and the metals in the dissolved and reducible-oxides fractions were transported to the anode or cathode by electromigration according to the chemical speciation of the metal ions in the pore water. Moreover, a portion of the metals that were initially in the residual fraction transitioned to the reducible and soluble fractions during electrokinetic treatment. However, this alteration was slow and resulted in decreasing metal removal rates as the electrokinetic treatment progressed. In addition, the use of NaOH, H3PO4, and Na2SO4 as electrolytes resulted in conditions that favored the precipitation of metal hydroxides, phosphates, and sulfates in the soil. These results demonstrated that metal removal was affected by the initial metal fractionation, metal speciation in the pore solution, and the physical-chemical parameters of the electrolytes, such as pH and electrolyte composition. Therefore, the treatment time, use of chemicals, and energy consumption could be reduced by optimizing pretreatment and by choosing appropriate electrolytes for the target metals. PMID:24972074

  2. Evolution du Pb, Zn, Cu, Ni et As dans le Bassin d'Arcachon (France). Impact de la biomasse végétale sur la géochimie d'un environment lagunaire

    NASA Astrophysics Data System (ADS)

    Lapaquellerie, Yvon; Latouche, Claude; Maillet, Noèle; Dumon, Jean-Claude; Carruesco, Christian

    1992-03-01

    The concentration of metals as Pb, Cu, Ni and As in suspended matters and sediments during 14 years shows for suspended matters and sediments that: Zn and Cu are increasing, Pb and As decreasing and Ni is stabilised. The evolution of the suspended matter can be explained by the quantitative evolution of algae and phanerogams during these last 14 years. The biomass evolution, which resulted in environmental nutrient contribution, intensifies the exchange factors of Pb and As in the lagoon. These remarks, beyond their local interests, provide notions of sedimentary environment model opposed to a polluting environment constituted by nautic tourism and a large area of monoculture (corn).

  3. SHRIMP U-Pb ages of xenotime and monazite from the Spar Lake red bed-associated Cu-Ag deposit, western Montana: Implications for ore genesis

    USGS Publications Warehouse

    Aleinikoff, John N.; Hayes, Timothy S.; Evans, Karl V.; Mazdab, Frank K.; Pillers, Renee M.; Fanning, C. Mark

    2012-01-01

    Xenotime occurs as epitaxial overgrowths on detrital zircons in the Mesoproterozoic Revett Formation (Belt Supergroup) at the Spar Lake red bed-associated Cu-Ag deposit, western Montana. The deposit formed during diagenesis of Revett strata, where oxidizing metal-bearing hydrothermal fluids encountered a reducing zone. Samples for geochronology were collected from several mineral zones. Xenotime overgrowths (1–30 μm wide) were found in polished thin sections from five ore and near-ore zones (chalcocite-chlorite, bornite-calcite, galena-calcite, chalcopyrite-ankerite, and pyrite-calcite), but not in more distant zones across the region. Thirty-two in situ SHRIMP U-Pb analyses on xenotime overgrowths yield a weighted average of 207Pb/206Pb ages of 1409 ± 8 Ma, interpreted as the time of mineralization. This age is about 40 to 60 m.y. after deposition of the Revett Formation. Six other xenotime overgrowths formed during a younger event at 1304 ± 19 Ma. Several isolated grains of xenotime have 207Pb/206Pb ages in the range of 1.67 to 1.51 Ga, and thus are considered detrital in origin. Trace element data can distinguish Spar Lake xenotimes of different origins. Based on in situ SHRIMP analysis, detrital xenotime has heavy rare earth elements-enriched patterns similar to those of igneous xenotime, whereas xenotime overgrowths of inferred hydrothermal origin have hump-shaped (i.e., middle rare earth elements-enriched) patterns. The two ages of hydrothermal xenotime can be distinguished by slightly different rare earth elements patterns. In addition, 1409 Ma xenotime overgrowths have higher Eu and Gd contents than the 1304 Ma overgrowths. Most xenotime overgrowths from the Spar Lake deposit have elevated As concentrations, further suggesting a genetic relationship between the xenotime formation and Cu-Ag mineralization.

  4. Genesis of the Au-Bi-Cu-As, Cu-Mo ± W, and base-metal Au-Ag mineralization at the Mountain Freegold (Yukon, Canada): constraints from Ar-Ar and Re-Os geochronology and Pb and stable isotope compositions

    NASA Astrophysics Data System (ADS)

    Bineli Betsi, Thierry; Lentz, David; Chiaradia, Massimo; Kyser, Kurt; Creaser, Robert A.

    2013-12-01

    The genesis of mineralized systems across the Mountain Freegold area, in the Dawson Range Cu-Au ± Mo Belt of the Tintina Au province was constrained using Pb and stable isotope compositions and Ar-Ar and Re-Os geochronology. Pb isotope compositions of sulfides span a wide compositional range (206Pb/204Pb, 18.669-19.861; 208Pb/204Pb, 38.400-39.238) that overlaps the compositions of the spatially associated igneous rocks, thus indicating a magmatic origin for Pb and probably the other metals. Sulfur isotopic compositions of sulfide minerals are broadly similar and their δ34S (Vienna-Canyon Diablo Troilite (V-CDT)) values range from -1.4 to 3.6 ‰ consistent with the magmatic range, with the exception of stibnite from a Au-Sb-quartz vein, which has δ34S values between -8.1 and -3.1 ‰. The δ34S values of sulfates coexisting with sulfide are between 11.2 and 14.2 ‰; whereas, those from the weathering zone range from 3.7 to 4.3 ‰, indicating supergene sulfates derived from oxidation of hypogene sulfides. The δ13C (Vienna Peedee Belemnite (VPDB)) values of carbonate range from -4.9 to 1.1 ‰ and are higher than magmatic values. The δ18O (V-SMOW) values of magmatic quartz phenocrysts and magmatic least-altered rocks vary between 6.2 and 10.1 ‰ and between 5.0 and 10.1 ‰, respectively, whereas altered magmatic rocks and hydrothermal minerals (quartz and magnetite) are relatively 18O-depleted (4.2 to 7.9 ‰ and -6.3 to 1.5 ‰, respectively). Hydrogen isotope compositions of both least-altered and altered igneous rock samples are D-depleted (from -133 to -161 ‰ Vienna-Standard Mean Ocean Water (V-SMOW)), consistent with differential magma degassing and/or post-crystallization exchange between the rocks and meteoric ground water. Zircon from a chlorite-altered dike has a U-Pb crystallization age of 108.7 ± 0.4 Ma; whereas, the same sample yielded a whole-rock Ar-Ar plateau age of 76.25 ± 0.53 Ma. Likewise, molybdenite Re-Os model ages range from 75.8 to

  5. Effects of heavy metal ions (Cu2+, Pb2+ and Cd2+) on DNA damage of the gills, hemocytes and hepatopancreas of marine crab, Charybdis japonica

    NASA Astrophysics Data System (ADS)

    Pan, Luqing; Liu, Na; Zhang, Hongxia; Wang, Jing; Miao, Jingjing

    2011-06-01

    There are rising concerns about the hazardous effects of heavy metals on the environment. In this study, comet assay and DNA alkaline unwinding assay were conducted on the tissues (gills, hepatopancreas, and hemocytes) of Charybdis japonica in order to illustrate genotoxicity of three heavy metal ions (Cu2+, Pb2+, and Cd2+) on the marine crabs C. japonica. The crabs were exposed to Cu2+ (10, 50, and 100 μg.L-1), Pb2+ (50, 250, and 500 μg L-1) and Cd2+ (5, 25, and 50 μg L-1), and the tissues were sampled at days 0.5, 1, 3, 6, 9, and 15. DNA alkaline unwinding assay was used for testing the DNA single strand break in gills and hepatopancreas and comet assay was employed for testing the DNA damage in hemocytes. The results showed that the DNA damage ( F-value) of gills in the crabs exposed to the three heavy metals was decreased gradually during the exposure periods and there was a dose-time response relationship in certain time, suggesting that the levels of DNA single strand break in all the experimental groups increased significantly compared to the controls. Changes of F-value in hepatopancreas of the crabs exposed to the three heavy metals were similar to those in gills except that the peak values were found in the 500 μg L-1 Pb2+ treatment group at day 3 and the 50 μg L-1 Cd2+ treatment group at day 9. The ranks of DNA damage in gills and hepatopancreas induced by the three heavy metal ions (50 μg L-1, day 15) were Cd2+ >Pb2+ >Cu2+ and Pb2+ >Cu2+ >Cd2+. The levels of DNA damage in gills were higher than those in hepatopancreas in the same experimental group. It can be concluded that indices of DNA damage can be used as the potential biomarkers of heavy metal pollution in marine environment.

  6. The molecular structure of the vanadate mineral mottramite [PbCu(VO4)(OH)] from Tsumeb, Namibia--a vibrational spectroscopic study.

    PubMed

    Frost, Ray L; Xi, Yunfei; López, Andrés; Corrêa, Lívia; Scholz, Ricardo

    2014-03-25

    We have studied a mineral sample of mottramite PbCu(VO4)(OH) from Tsumeb, Namibia using a combination of scanning electron microscopy with EDX, Raman and infrared spectroscopy. Chemical analysis shows principally the elements V, Pb and Cu. Ca occurs as partial substitution of Pb as well as P and As in substitution to V. Minor amounts of Si and Cr were also observed. The Raman band of mottramite at 829 cm(-1), is assigned to the ν1 symmetric (VO4(-)) stretching mode. The complexity of the spectra is attributed to the chemical composition of the Tsumeb mottramite. The ν3 antisymmetric vibrational mode of mottramite is observed as very low intensity bands at 716 and 747 cm(-1). The series of Raman bands at 411, 439, 451 cm(-1) and probably also the band at 500 cm(-1) are assigned to the (VO4(-)) ν2 bending mode. The series of Raman bands at 293, 333 and 366 cm(-1) are attributed to the (VO4(-)) ν4 bending modes. The ν3, ν3 and ν4 regions are complex for both minerals and this is attributed to symmetry reduction of the vanadate unit from Td to Cs. PMID:24316538

  7. SWASV speciation of Cd, Pb and Cu for the determination of seawater contamination in the area of the Nicole shipwreck (Ancona coast, Central Adriatic Sea).

    PubMed

    Annibaldi, Anna; Illuminati, Silvia; Truzzi, Cristina; Scarponi, Giuseppe

    2011-12-01

    The study reports for the first time on the heavy metal contamination of the waters surrounding a shipwreck lying on the sea floor. Square wave anodic stripping voltammetry has been used for a survey of the total and dissolved Cd, Pb and Cu contents of the seawater at the site of the sinking of the Nicole M/V (Coastal Adriatic Sea, Italy). Results show that the hulk has a considerable impact as regards all three metals in the bottom water, especially for the particulate fraction concentrations, which increased by factors of ≈ 9 (Cd), ≈ 3 (Pb) and ≈ 5 (Cu). The contaminated plume extended downstream for about 2 miles. Much lower contamination was observed for dissolved bottom concentrations; nevertheless Pb (0.56 ± 0.03 nmol/L) is higher than the Italian legal limits established for 2015 and Cd (0.23 ± 0.03 nmol/L) is very close the limit of Cd will be exceeded if the hulk is not removed. PMID:21982428

  8. Chemical speciation of Fe, Mn, Pb, Zn, Cd, Cu, Co, Ni and Cr in the suspended particulate matter off the Mejerda River Delta (Gulf of Tunis, Tunisia)

    NASA Astrophysics Data System (ADS)

    Helali, Mohamed Amine; Oueslati, Walid; Zaaboub, Noureddine; Added, Ayed; Aleya, Lotfi

    2016-06-01

    Fluxes of suspended particulate matter (SPM) and their associated metals were performed off the Mejerda River Delta during both the wet (March) and the dry (July) seasons in 2012, using sediment traps at study stations at depths of 10, 20 and 40 m. Fluxes nearest to the Mejerda outlet were more significant, especially during winter (36 g m-2 day-1), but dissipated further offshore, 24.5-6 g m-2 day-1 at the 20 m and 21.8-4.8 g m-2 day-1 at the 40 m stations. Many variations observed in seasonal and spatial metal fluxes are similar to those of SPM, in particular Pb and Zn, probably because they are associated with the mining activity characteristic of the Mejerda catchment. Chemical speciation reveals that most of the metals (20-100%) are bound to the residual fraction. The most toxic metals (Pb, Zn) are bound in part to the exchangeable fraction (20-50% for Pb and 5-15% for Zn) making them relatively bioavailable and therefore potentially toxic. While Cu and Cd fluxes are not always clearly established according to season, both metals are apparently sequestered deep in the sediment, bound especially to clays (40-80% for Cd and up to 100% for Cu).

  9. Predicting As, Cd, Cu, Pb and Zn levels in grasses (Agrostis sp. and Poa sp.) and stinging nettle (Urtica dioica) applying soil-plant transfer models.

    PubMed

    Boshoff, Magdalena; De Jonge, Maarten; Scheifler, Renaud; Bervoets, Lieven

    2014-09-15

    The aim of this study was to derive regression-based soil-plant models to predict and compare metal(loid) (i.e. As, Cd, Cu, Pb and Zn) concentrations in plants (grass Agrostis sp./Poa sp. and nettle Urtica dioica L.) among sites with a wide range of metal pollution and a wide variation in soil properties. Regression models were based on the pseudo total (aqua-regia) and exchangeable (0.01 M CaCl2) soil metal concentrations. Plant metal concentrations were best explained by the pseudo total soil metal concentrations in combination with soil properties. The most important soil property that influenced U. dioica metal concentrations was the clay content, while for grass organic matter (OM) and pH affected the As (OM) and Cu and Zn (pH). In this study multiple linear regression models proved functional in predicting metal accumulation in plants on a regional scale. With the proposed models based on the pseudo total metal concentration, the percentage of variation explained for the metals As, Cd, Cu, Pb and Zn were 0.56%, 0.47%, 0.59%, 0.61%, 0.30% in nettle and 0.46%, 0.38%, 0.27%, 0.50%, 0.28% in grass. PMID:25000582

  10. Heavy metal (Pb, Zn, Cd, Fe, and Cu) contents of plant foliage near the Anvil Range lead/zinc mine, Faro, Yukon Territory.

    PubMed

    Pugh, Rachel E; Dick, David G; Fredeen, Arthur L

    2002-07-01

    Mining and processing of lead (Pb)/zinc (Zn) ore at the Anvil Range mine occurred near the town of Faro in the Yukon Territory, Canada, for approximately 30 years, beginning in 1968. A study was undertaken to examine whether the mining activities had left a detectable "footprint" on the environment in the way of heavy metal phytoaccumulation. Foliage of three native plant species was sampled: bog blueberry (Vaccinium uliginosum), Labrador tea (Ledum groenlandicum), and willow (Salix sp.), at approximately 0.25, 2.5, 12, 30, and 200 (control) km distant from the mill (ore-processing facility at the mine). Foliage samples were oven-dried, wet- or dry-ashed, and analyzed for metal content using ICP-AES. In addition to Pb and Zn, the primary ore constituents, copper (Cu), iron (Fe), and cadmium (Cd), were also assayed. As expected, foliar Pb and Zn concentrations were elevated in plants at the sites closest to the mill, i.e., 0.25 and 2.5 km from the mine facility. Copper and Fe, both essential nutrients for plants, were also elevated in foliage at the sites closest to the mill, but not to a level that would be of concern. Foliar Cd levels were highest in Salix relative to the other species but were not affected by proximity to the mill. Results suggest that Ledum may be the best indicator of high environmental concentrations of Pb, while Salix may be the best indicator of elevated Zn and Cd. PMID:12297090

  11. Peculiarities of thermoelectric half-Heusler phase formation in Gd-Ni-Sb and Lu-Ni-Sb ternary systems

    NASA Astrophysics Data System (ADS)

    Romaka, V. V.; Romaka, L.; Horyn, A.; Rogl, P.; Stadnyk, Yu; Melnychenko, N.; Orlovskyy, M.; Krayovskyy, V.

    2016-07-01

    The phase equilibria in the Gd-Ni-Sb and Lu-Ni-Sb ternary systems were studied at 873 K by X-ray and metallographic analyses in the whole concentration range. The interaction of the elements in the Gd-Ni-Sb system results the formation of five ternary compounds at investigated temperature: Gd5Ni2Sb (Mo5SiB2-type), Gd5NiSb2 (Yb5Sb3-type), GdNiSb (MgAgAs-type), Gd3Ni6Sb5 (Y3Ni6Sb5-type), and GdNi0.72Sb2 (HfCuSi2-type). At investigated temperature the Lu-Ni-Sb system is characterized by formation of the LuNiSb (MgAgAs-type), Lu5Ni2Sb (Mo5SiB2-type), and Lu5Ni0.56Sb2.44 (Yb5Sb3-type) compounds. The disordering in the crystal structure of half-Heusler GdNiSb and LuNiSb was revealed by EPMA and studied by means of Rietveld refinement and DFT modeling. The performed electronic structure calculations are in good agreement with electrical transport property studies.

  12. Magnetic zeolite NaA: synthesis, characterization based on metakaolin and its application for the removal of Cu2+, Pb2+.

    PubMed

    Liu, Haibo; Peng, Shuchuan; Shu, Lin; Chen, Tianhu; Bao, Teng; Frost, Ray L

    2013-06-01

    The optimum parameters for synthesis of zeolite NaA based on metakaolin were investigated according to results of cation exchange capacity and static water adsorption of all synthesis products and selected X-ray diffraction (XRD). Magnetic zeolite NaA was synthesized by adding Fe3O4 in the precursor of zeolite. Zeolite NaA and magnetic zeolite NaA were characterized with scanning electron microscopy (SEM) and XRD. Magnetic zeolite NaA with different Fe3O4 loadings was prepared and used for removal of heavy metals (Cu(2+), Pb(2+)). The results show the optimum parameters for synthesis zeolite NaA are SiO2/Al2O3=2.3, Na2O/SiO2=1.4, H2O/Na2O=50, crystallization time 8h, crystallization temperature 95 °C. The addition of Fe3O4 makes the NaA zeolite with good magnetic susceptibility and good magnetic stability regardless of the Fe3O4 loading, confirming the considerable separation efficiency. Additionally, Fe3O4 loading had a little effect on removal of heavy metal by magnetic zeolite, however, the adsorption capacity still reaches 2.3 mmol g(-1) for Cu(2+), Pb(2+) with a removal efficiency of over 95% in spite of 4.7% Fe3O4 loading. This indicates magnetic zeolite can be used to remove metal heavy at least Cu(2+), Pb(2+) from water with metallic contaminants and can be separated easily after a magnetic process. PMID:23340053

  13. Effects of tree vegetation and waste amendments on the fractionation of Cr, Cu, Ni, Pb and Zn in polluted mine soils.

    PubMed

    Asensio, Verónica; Vega, Flora A; Singh, Bal Ram; Covelo, Emma F

    2013-01-15

    Soils at a depleted copper mine in Touro (Galicia, Spain) are physically and chemically degraded and have also polluted the surrounding area. Due to these environmental problems and the large area of these mine soils, the reclamation strategies carried out at Touro have consisted of planting trees (pine or eucalyptus), amending with waste material (sewage sludge and paper mill residues), or using both treatments. Tree planting has been carried out for 21 years and waste amending for 10. Two different zones were selected in the mine (the settling pond and mine tailing) in order to evaluate the effect of the different reclamation practices on the chemical fractions of Cr, Cu, Ni, Pb and Zn. The results showed that soils in the untreated sites were polluted by Cr and Cu. Planting pines and eucalyptus on mine soils decreased the concentration of these heavy metals in non-mobile soil fractions. Amendments also attenuated pollution by Cr and Cu as the wastes that were used had lower concentrations than the untreated mine soils. Planting trees increased Ni, Pb and Zn retention in the non-mobile fractions, preventing them from being leached into surrounding areas. However, caution should be exercised when adding organic wastes, as they can lead to increase concentrations of Ni, Pb and Zn and their phytoavailable form. The results also showed that changes in the chemical fractionation of heavy metals in soils was more influenced by the clay percentage and both dissolved and soil organic carbon (SOC and DOC) than by soil pH or cation exchange capacity. PMID:23220134

  14. Nonequilibrium leaching behavior of metallic elements (Cu, Zn, As, Cd, and Pb) from soils collected from long-term abandoned mine sites.

    PubMed

    Kim, Juhee; Hyun, Seunghun

    2015-09-01

    Leaching of metallic elements (Cu, Zn, As, Cd, and Pb) from two mine-impacted soils (DY and BS) was evaluated by batch decant-refill and seepage flow experiments. During eight consecutive leaching steps, aqueous As concentrations remained relatively constant (approx. 1.6 and 0.1 mg L(-)(1) for DY and BS, respectively), while Cu (0.01-3.2 mg L(-1)), Zn (0.2-42 mg L(-1)), and Cd (0.004-0.3 mg L(-1)) were quickly reduced. The reduction of Pb concentration (0.007-0.02 mg L(-1) and 0.2-0.9 mg L(-1) for DY and BS, respectively) was much lesser. This pattern was well-explained by the biphasic leaching model by allocating a large fast leaching fraction (ffast>0.2) for Cu, Zn, and Cd while a negligible ffast for As and Pb (<0.001). For all elements in column effluents, mass export through first-flush and steady-state concentration were elevated under slow seepage, with the greatest impact observed for As. Element export was enhanced after flow interruption, especially under fast seepage. A transient drop in As export in slow seepage was likely due to sorption back to soil phase during the quiescent period. The ratio of Fe(2+)/Fe(3+) and SO4(2-) concentration, related to the dissolution of sulfide minerals, were also seepage rate-dependent. The results of batch and column studies imply that the leachate concentration will be enhanced by initial seepage and will be perturbed after quiescent wetting period. The conversion from kinetically leachable pool to readily leachable pool is likely responsible for nonequilibrium metal leaching from the long-term abandoned mine soils. PMID:25935604

  15. The Long-Term Fate of Cu2+, Zn2+, and Pb2+ Adsorption Complexes at the Calcite Surface: An X-ray Absorption Spectroscopy Study

    SciTech Connect

    Elzinga,E.; Rouff, A.; Reeder, R.

    2006-01-01

    In this study, the speciation of Zn{sup 2+}, Pb{sup 2+}, and Cu{sup 2+} ions sorbed at the calcite surface was monitored during a 2.5-year reaction period, using extended X-ray absorption spectroscopy to characterize metal speciation on the molecular scale. Experiments were performed using pre-equilibrated calcite-water suspensions of pH 8.3, at metal concentrations below the solubility of metal hydroxide and carbonate precipitates, and at constant metal surface loadings. The EXAFS results indicate that all three metals remained coordinated at the calcite surface as inner-sphere adsorption complexes during the 2.5-year ageing period, with no evidence to suggest slow formation of dilute metal-calcite solid solutions under the reaction conditions employed. All three divalent metals were found to form non-octahedral complexes upon coordination to the calcite surface, with Zn{sup 2+} adsorbing as a tetrahedral complex, Cu{sup 2+} as a Jahn-Teller distorted octahedral complex, and Pb{sup 2+} coordinating as a trigonal- or square-pyramidal surface complex. The non-octahedral configurations of these surface complexes may have hindered metal transfer from the calcite surface into the bulk, where Ca{sup 2+} is in octahedral coordination with respect to first-shell O. The use of pre-equilibrated calcite suspensions, with no net calcite dissolution or precipitation, likely prevented metal incorporation into the lattice as a result of surface recrystallization. The results from this study imply that ageing alone does not increase the stability of Zn{sup 2+}, Pb{sup 2+}, and Cu{sup 2+} partitioning to calcite if equilibrium with the solution is maintained during reaction; under these conditions, these metals are likely to remain available for exchange even after extended sorption times.

  16. Analysis of Zn, Cd, As, Cu, Pb, and Fe in snails as bioindicators and soil samples near traffic road by ICP-OES.

    PubMed

    Massadeh, Adnan M; Alomary, Ahmed A; Mir, Sayeeda; Momani, Fouad A; Haddad, Hazem I; Hadad, Yazen A

    2016-07-01

    Snails are used as biological indicators of the environment pollution for heavy metals. Living snail samples were collected from different sites at the city of Irbid-Jordan and classified according to their morphological features including Helix pelasga, Eobania vermiculata, Xeropicta derbentina, Oychilus, Xerocrassa seetzenii, Xerocrassa simulata, and Pila. Zn, Cd, As, Cu, Pb, and Fe levels were measured by inductively coupled plasma-optical emission spectroscopy. Results indicated that metal concentrations in all snail shell samples were with an average and range for Zn 22.4 (6.5-105.5) μg g(-1), Cd 7.8 (0.4-48.1) μg g(-1), As 25.9 (0.7-248.5) μg g(-1), Cu 15.1 (1.6-69.0) μg g(-1), Pb 0.4 (0.2-1.7) μg g(-1), and Fe 119.6 (14.0-1102.0) μg g(-1), whereas, in soil samples, the average and range for Zn 204.0 (12.0-709.0) μg g(-1), Cd 5.7 (0.2-39.5) μg g(-1), As 3.2 (1.8-5.2) μg g(-1), Cu 22.1 (2.3-77.4) μg g(-1), Pb 0.2 (0.1-0.3) μg g(-1), and Fe 242.4 (25.0-680.0) μg g(-1). PMID:27026544

  17. Measurement of the mass attenuation coefficient from 81 keV to 1333 keV for elemental materials Al, Cu and Pb

    NASA Astrophysics Data System (ADS)

    Gjorgieva, Slavica; Barandovski, Lambe

    2016-03-01

    The mass attenuation coefficients (μ/ρ) for 3 high purity elemental materials Al, Cu and Pb were measured in the γ-ray energy range from 81 keV up to 1333 keV using 22Na, 60Co 133Ba and 133Cs as sources of gamma radiation. Well shielded detector (NaI (Tl) semiconductor detector) was used to measure the intensity of the transmitted beam. The measurements were made under condition of good geometry, assuring that any photon absorbed or deflected appreciably does not reach the detector. The measured values are compared with the theoretical ones obtained by Seltzer (1993).

  18. Assessment of Cu, Pb, and Zn contamination in sediment of north western Peninsular Malaysia by using sediment quality values and different geochemical indices.

    PubMed

    Yap, C K; Pang, B H

    2011-12-01

    Surface sediments were collected from the north western aquatic area (13 intertidal sites and 5 river drainages) of Peninsular Malaysia, which were suspected to have received different anthropogenic sources. These sites included town areas, ports, fishing village, industrial areas, highway sides, jetties and some relatively unpolluted sites. The present study revealed that 4.79-32.91 μg/g dry weight for Cu, 15.85-61.56 μg/g dry weight for Pb, and 33.6-317.4 μg/g dry weight for Zn based on 13 intertidal surface sediments while those based on 5 river drainage surface sediments were 10.24-119.6 μg/g dry weight for Cu, 26.7-125.7 μg/g dry weight for Pb and 88.7-484.1 μg/g dry weight for Zn. In general, the metal levels in the drainage sediments are higher than in the intertidal sediments, suggesting dilution factor in the intertidal sediment and direct effluent from point sources in the drainage sediment. In particular, the total concentrations of Cu, Pb, and Zn for the sampling site at Kuala Kurau Town exceeded the Effect Range Median values for Cu, Pb, and Zn for assessments of sediment quality values for freshwater sediment as proposed by MacDonald et al. (Arch Environ Contam Toxicol 39:20-31, 2000), thus adverse biological effects would be observed above this level. Assessment using enrichment factor (using Fe as a normalizer) and geoaccumulation index showed that the three metals at Kuala Kurau Town and Juru Industry drainage were evidenced as having more enrichment and mostly due to non-natural sources. However, caution should be exercised that the interpretation can only become valid when the ratios, indices, and sediment quality values are combined. This is due to the fact that not all the established indices are applicable and, to a certain extent, some of them should be further revised and improved to suit a different metal for Malaysian sediment. Undoubtedly, sites near drainages at Kuala Kurau Town and Juru River Basin need greater attention to

  19. Superconducting Bi(1.5)Pb(0.5)Sr2Ca2Cu3O(x) ceramics by rapid melt quenching and glass crystallization

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.

    1990-01-01

    The preparation of superconducting Bi(1.5)Pb(0.5)Sr2Ca2Cu3O(x) in the glassy state is described, and the results of a study of its crystallization kinetics are presented. The annealing parameters for transforming the glass into a superconductor containing a large fraction of the high-Tc phase were determined. It was found that prolonged annealing (longer than 10 days) in air at 840 C, followed by slow cooling, results in the Tc of 107.2 K and a sharp transition of 2 K.

  20. Compressibility and phase transitions in Bi(1.6)Pb(0.4)Sr2Ca(2.5)Cu(3.5)O(x) polycrystalline ceramic

    NASA Astrophysics Data System (ADS)

    Balankina, E. S.

    1991-11-01

    Ultrasonic resonance measurements of the bulk modulus of elasticity were conducted for disk (15 mm in diameter, 3 mm thick) specimens of polycrystalline Bi(1.6)Pb(0.4)Sr2Ca(2.5)Cu(3.5)O(x) ceramic in the temperature range 85-300 K. The bulk modulus of elasticity is found to increase monotonically as the temperature decreases and exibits well defined anomalies in the form of discontinuities and slope changes at 102, 120, 200, and 255 K. The possible mechanisms of the observed anomalies are discussed.

  1. Mineral potential tracts for polymetallic Pb-Zn-Cu vein deposits (phase V, deliverable 71): Chapter I in Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)

    USGS Publications Warehouse

    Beaudoin, Georges

    2015-01-01

    In Mauritania, mineral occurrences of the polymetallic Pb-Zn-Cu vein deposit type are found near the Florence-El Khdar shear zone in northeast Mauritania. The deposits visited were deemed representative of other similar occurrences and consist of quartz veins with trace sulfides. The low sulfide and Pb-Zn-Cu content in the quartz veins is unlike producing polymetallic Pb-Zn-Cu vein deposits, such that the veins are not considered to belong to this deposit type. Mineral potential tracts for polymetallic Pb-ZnCu veins are highly speculative considering the lack of known mineralization belonging to this deposit type. Mineral potential tracts for polymetallic Pb-Zn-Cu veins are associated with and surround major shear zones in the Rgueïbat Shield and zones of complex faulting in the southern Mauritanides, at the exclusion of the imbricated thrust faults that are not considered favorable for this deposit type. No skarn and replacement deposits have been documented in Mauritania and the low mineral potential is indicated by lack of causative Mesozoic and Cenozoic mafic to felsic stocks.

  2. Correlations between speciation of Cd, Cu, Pb And Zn in sediment and their concentrations in total soft tissue of green-lipped mussel Perna viridis from the west coast of Peninsular Malaysia.

    PubMed

    Yap, C K; Ismail, A; Tan, S G; Omar, H

    2002-04-01

    Total concentrations and speciation of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in surface sediment samples were correlated with the respective metal measured in the total soft tissue of the green-lipped mussel Perna viridis, collected from water off the west coast of Peninsular Malaysia. The aim of this study is to relate the possible differences in the accumulation patterns of the heavy metals in P. viridis to those in the surface sediment. The sequential extraction technique was employed to fractionate the sediment into 'freely leachable and exchangeable' (EFLE), 'acid-reducible,' 'oxidisable-organic' and 'resistant' fractions. The results showed that significant (P<.05) correlations were observed between Cd in P. viridis and Cd in the sediment (EFLE fraction and total Cd), Cu in P viridis and Cu in the sediment (EFLE and 'acid-reducible' fractions and total Cu) and Pb in P viridis and Pb in the sediment ('oxidisable-organic' fraction and total Pb). No significant correlation (P > .05) was found between Zn in P viridis and all the sediment geochemical fractions of Zn and total Zn in the sediment. This indicated that Zn was possibly regulated from the soft tissue of P. viridis. The present results supported the use of P viridis as a suitable biomonitoring agent for Cd, Cu and Pb. PMID:12046948

  3. Preconcentration of Cu(II), Fe(III) and Pb(II) with 2-((2-aminoethylamino)methyl)phenol-functionalized activated carbon followed by ICP-OES determination.

    PubMed

    He, Qun; Hu, Zheng; Jiang, Yin; Chang, Xijun; Tu, Zhifeng; Zhang, Lina

    2010-03-15

    A procedure for separation and preconcentration trace amount of Cu(II), Fe(III) and Pb(II) by 2-((2-aminoethylamino)methyl)phenol-functionalized activated carbon (AC-AMP) packed column has been proposed. Under the optimized conditions (pH 4, flow rate 2.0 mL min(-1)), Cu(II), Fe(III) and Pb(II) were retained on the column, then quantitatively eluted by 2 mL 1 mol L(-1) nitric acid solution and determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The tolerance limits of electrolytes were very high. The adsorption capacity of AC-AMP was found to be 12.1, 67.1, and 16.2 mg g(-1) for Cu(II), Fe(III), and Pb(II), respectively. According to the definition of International Union of Pure and Applied Chemistry, the detection limits (3 sigma) of this method for Cu(II), Fe(III) and Pb(II) were 0.27, 0.41 and 0.16 microg L(-1), respectively. The relative standard deviation under optimum conditions is less than 3.0% (n=11). The proposed method has been validated by analyzing a certified reference material and successfully applied to the preconcentration and determination of Cu(II), Fe(III), and Pb(II) in actual samples with satisfactory results. PMID:19926213

  4. Vapor pressures of bismuth, lead, and copper components in Bi sub 2 Sr sub 1. 7 CaCu sub 2 O sub y and Bi sub 1. 7 Pb sub 0. 3 Sr sub 1. 7 Ca sub 2 Cu sub 3 O sub y superconductor ceramics

    SciTech Connect

    Stata, T.; Sakai, K.; Tashiro, S. )

    1992-04-01

    The vapor pressures of the Bi system superconductor oxides Bi{sub 2}Sr{sub 1.7}CaCu{sub 2}O{sub y} (BSCCO) and Bi{sub 1.7}Pb{sub 0.3}Sr{sub 1.7}Ca{sub 2}Cu{sub 3}O{sub y} (BPSCCO) were determined by the transpiration method in atmospheres of O{sub 2}, air, and N{sub 2}, in the temperature range 730{degrees} to 820{degrees} C. The Bi/Cu atomic ratios of the vapor increased from 0.8 to 4.6 with increasing temperature for BSCCO, and the Bi/Cu/Pb ratio was 1.1/1/72 for BPSCCO at 800{degrees} C in O{sub 2}. Vapor pressures for the vapor species Cu, CuO, Bi{sub 4}O{sub 6}, PbO, and Pb{sub 2}O{sub 2} were calculated using the literature values. Vapor pressures for Cu were higher and those for both Bi and Pb lower than values estimated from the pure oxides. These values are discussed in the present paper in relation to crystal structure.

  5. Effects of selected heavy metals (Pb, Cu, Ni, and Cd) in the aquatic medium on the restoration potential and accumulation in the stem cuttings of the terrestrial plant, Talinum triangulare Linn.

    PubMed

    Rajkumar, K; Sivakumar, S; Senthilkumar, P; Prabha, D; Subbhuraam, C V; Song, Y C

    2009-10-01

    The heavy metal (Cu, Pb, Ni, and Cd) accumulation capacity of the stem cuttings of the terrestrial, ornamental plant, Talinum triangulare was assessed in hydroponic medium. The stem cuttings of T. triangulare, grew well in distilled water regenerating roots and aerial parts. On exposure to various concentrations of Cu, Pb, Ni, and Cd, a concentration dependent decrease was observed in the number of leaves produced and roots regenerated and an increase in the number of days required for the initiation of roots. The number of leaves produced showed an increasing trend in almost all treatment concentrations of Cu, Pb, Ni, and Cd with an increase in the duration of experiment, whereas, with an increase in the treatment concentration of metals a significant (P < 0.05) decrease was observed in the number of leaves produced. The number of days required for root initiation in metal solutions, however, increased with increasing concentration of Cu, Pb, Ni, and Cd. The root development was completely arrested from 10 mg l(-1) of Ni and 4 mg l(-1) of Cd. Compared to the control, a significant decrease was recorded in the number of roots produced in all treatment concentrations of Cu, Pb, Ni, and Cd. Pink colouration of metal solution consequent to leaching of plant pigment from T. triangulare was observed which was not persistent and disappeared after a few days. Decaying of stem was observed when exposed to Ni and Cd but not to Cu and Pb. Although, copper accumulation by T. triangulare at treatment concentration of 15 and 20 mg l(-1) exceeded 1,000 mg kg(-1) dry matter, necessary pot culture experiment is required before "T. triangulare" can be definitely classified as a Cu hyperaccumulator. PMID:19590954

  6. High thermoelectric performance in the multi-valley electronic system Zr{sub 3}Ni{sub 3−x}Co{sub x}Sb{sub 4} and the high-mobility Zr{sub 3}Ni{sub 3−x}Cu{sub x}Sb{sub 4}

    SciTech Connect

    Tamaki, H.; Kanno, T.; Sakai, A.; Takahashi, K.; Kusada, H.; Yamada, Y.

    2014-03-24

    We report synthesis and thermoelectric performance of the p-type Zr{sub 3}Ni{sub 3−x}Co{sub x}Sb{sub 4} and the n-type Zr{sub 3}Ni{sub 3−x}Cu{sub x}Sb{sub 4}, which are derived from the same parent semiconductor Zr{sub 3}Ni{sub 3}Sb{sub 4}. We found a high thermoelectric performance for both the p-type compound (the figure-of-merit ZT is 0.52 at 760 K) and the n-type compound (ZT = 0.41 at 670 K). ZT of the p-type compound exceeded the value of the p-type half-Heusler compounds consisting of similar elements. The Hall-coefficient measurements indicate that the high ZT in the n-type compounds is a consequence of the high electron mobility of 52.4 cm{sup 2}/Vs. In contrast, the p-type compounds showed higher ZT in spite of much lower mobility. We discuss the mechanism for the high ZT in the p-type compound from the viewpoint of the multi-valley band structure.

  7. Atmospheric concentrations and size distributions of aircraft-sampled Cd, Cu, Pb and Zn over the southern bight of the North Sea

    NASA Astrophysics Data System (ADS)

    Injuk, J.; Otten, Ph.; Laane, R.; Maenhaut, W.; Van Grieken, R.

    In an effort to assess the atmospheric input of heavy metals to the Southern Bight of the North Sea, aircraft-based aerosol samplings in the lower troposphere were performed between September 1988 and October 1989. Total atmospheric particulate and size-differentiated concentrations of Cd, Cu, Pb and Zn were determined as a function of altitude, wind direction, air-mass history and season. The obtained data are compared with results of ship-based measurements carried out previously and with literature values of Cu, Pb and Zn, for the marine troposphere of the southern North Sea. The results point out the high variability of the concentrations with the meterological conditions, as well as with time and location. The experimentally found particle size distribution are bimodal with a significant difference in fractions of small and large particles. These large aerosol particles have a direct and essential impact on the air-to-sea transfer of anthropogenic trace metals, in spite of their low numerical abundance and relatively low heavy metal content.

  8. Removal of Pb2+, Hg2+, and Cu2+ by Chain-Like Fe3O4@SiO2@Chitosan Magnetic Nanoparticles.

    PubMed

    Shi, Haowei; Yang, Junya; Zhu, Lizhong; Yang, Yuxiang; Yuan, Hongming; Yang, Yubing; Liu, Xiangnong

    2016-02-01

    In this paper, the chain-like core-shell structure Fe3O4@SiO2@Chitosan composite nanoparticles were synthesized by a two-step coating and following crosslinking glutaraldehyde on chitosan shell. The composite particles showed nearly monodisperse 105 sized particles with a core diameter of 80 nm and chitosan shell thickness of 12 nm. The synthesis conditions of the product were studied, and the morphology and properties of the composite nanoparticles were characterized by IR, XRD, TEM, SEM, EDS and VSM. The adsorption properties of Hg2+, Pb2+ or Cu2+ ions on Fe3O4, Fe3O4@SiO2 and the composite particles were in detail studied using the colorimetric method based on forming colored mercuric dithizone, rhodamine-Pb2+ complex and DDTC-Cu(2+) complex. The results showed, adsorption isotherm, kinetics and separation coefficient of heavy metal ions on these three magnetic nanoparticles were concerned with pH, metal ions' electronic configuration, silica coating and chitosan shell respectively. In addition, the recycle efficiency was also studied. The findings demonstrated that Fe3O4@SiO2@Chitosan composite nanoparticles have great application value in the adsorption and separation of heavy metal ions. PMID:27433691

  9. Crown ether-modified electrodes for the simultaneous stripping voltammetric determination of Cd(II), Pb(II) and Cu(II).

    PubMed

    Serrano, Núria; González-Calabuig, Andreu; del Valle, Manel

    2015-06-01

    This work describes the immobilization of 4-carboxybenzo-18-crown-6 (CB-18-crown-6) and 4-carboxybenzo-15-crown-5 (CB-15-crown-5) assisted by lysine on aryl diazonium salt monolayers anchored to the surface of graphite-epoxy composite electrodes (GEC), and their use for the simultaneous determination of Cd(II), Pb(II) and Cu(II) by differential pulse anodic stripping voltammetry (DPASV). These modified electrodes display a good repeatability and reproducibility with detection and quantification limits at levels of µg L(-1) (ppb), confirming their suitability for the determination of Cd(II), Pb(II) and Cu(II) ions in environmental samples. The overlapped nature of the multimetal stripping measurements was resolved by employing the two-sensor array CB-15-crown-5-GEC and CB-18-crown-6-GEC, since the metal complex selectivity exhibited by the considered ligands could add some discrimination power. For the processing of the voltammograms, Discrete Wavelet Transform and Causal Index were selected as preprocessing tools for data compression coupled with an artificial neural network for the modeling of the obtained responses, allowing the resolution of mixtures of these metals with good prediction of their concentrations (correlation with expected values for an external test subset better than 0.942). PMID:25863381

  10. Effects of sodium selenite on some biochemical and hematological parameters of rainbow trout (Oncorhynchus mykiss Walbaum, 1792) exposed to Pb2+ and Cu2+.

    PubMed

    Ates, Burhan; Orun, Ibrahim; Talas, Zeliha Selamoglu; Durmaz, Gokhan; Yilmaz, Ismet

    2008-03-01

    This study was carried out to understand the preventive effect of selenium (Se4+) on heavy metal stress induced by lead and copper in rainbow trout (Oncorhynchus mykiss). Variation in glutathione peroxidase (Se-GSH-Px) and superoxide dismutase (SOD) activity, and in malondialdehyde (MDA) levels in liver, spleen, heart, and brain tissues of rainbow trout after 72 h of exposure to Pb2+ and Cu2+ were investigated in the presence and absence of Se4+. In the presence of Se4+, Se-GSH-Px activity and SOD activity were found to be higher and MDA levels were lower compared with in its absence. Hematological parameters were also determined and it has been observed that total leukocyte count (WBC), mean cell volume (MCV), and mean cell hemoglobin (MCH) were increased and erythrocyte number (RBC), hemoglobin (Hb), and hematocrit value (Hct; P < 0.05) were decreased in fish exposed to heavy metals in the absence of selenium. Selenium presence recovered hematological parameters to normal levels. In the light of our findings, it could be stated that Pb2+ and Cu2+ lead to dramatic changes in biochemical and hematological parameters and selenium caused these parameters to converge to control levels when it was administered concurrently with these heavy metals. PMID:18649023

  11. Direct observation of bulk charge modulations in optimally doped Bi1.5Pb0.6Sr1.54CaCu2O8+δ

    NASA Astrophysics Data System (ADS)

    Hashimoto, M.; Ghiringhelli, G.; Lee, W.-S.; Dellea, G.; Amorese, A.; Mazzoli, C.; Kummer, K.; Brookes, N. B.; Moritz, B.; Yoshida, Y.; Eisaki, H.; Hussain, Z.; Devereaux, T. P.; Shen, Z.-X.; Braicovich, L.

    2014-06-01

    Bulk charge density modulations, recently observed in high critical-temperature (Tc) cuprate superconductors, coexist with the so-called pseudogap and compete with superconductivity. However, its direct observation has been limited to a narrow doping region in the underdoped regime. Using energy-resolved resonant x-ray scattering we have found evidence for such bulk charge modulations, or soft collective charge modes (soft CCMs), in optimally doped Bi1.5Pb0.6Sr1.54CaCu2O8+δ (Pb-Bi2212) around the summit of the superconducting dome with momentum transfer q∥˜0.28 reciprocal lattice units (r.l.u.) along the Cu-O bond direction. The signal is stronger at T ≃Tc than at lower temperatures, thereby confirming a competition between soft CCMs and superconductivity. These results demonstrate that soft CCMs are not constrained to the underdoped regime, suggesting that soft CCMs appear across a large part of the phase diagram of cuprates and are intimately entangled with high-Tc superconductivity.

  12. Adsorption of Pb(II), Cr(III), Cu(II), Cd(II) and Ni(II) onto a vanadium mine tailing from aqueous solution.

    PubMed

    Shi, Taihong; Jia, Shiguo; Chen, Ying; Wen, Yinghong; Du, Changming; Guo, Huilin; Wang, Zhuochao

    2009-09-30

    The adsorption of heavy metal cations Pb(II), Cr(III), Cu(II), Cd(II) and Ni(II) from aqueous solution by a mine tailing which mainly contains muscovite was investigated. The property of the mineral was investigated by using SEM, FT-IR, XRD and BET analysis. pH(pzc) was measured by an titration technique to give a value of 5.4+/-0.1. Kinetics experiments indicated that the processes can be simulated by pseudo-second-order model. Total adsorption amounts of the heavy metal increased, while the adsorption density decreased when the solid-to-liquid ratio (S/L) increased. Grain size did not affect the adsorption capacity significantly. The resulting isotherms can be described by Frendlich relationship. And the maximum adsorption capacity (molar basis) followed the order of Cr(III)>Pb(II)>Cu(II)>Ni(II)>Cd(II). Thermodynamic analysis showed that the adsorption processed were endothermic and may be chemical in nature with positive DeltaH(0). The positive DeltaS(0) suggested that dissociative processed were involved. Small positive DeltaG(0) suggested that the adsorption processes required a small amount of energy. Adsorption processes were slightly affected by electrolyte ion concentration but strongly dependent on pH value. The most possible mechanism of the adsorption processes involve the inner-sphere-complexions by the aluminol or silanol groups on the surface of the mineral. PMID:19427115

  13. Photo-transformation of pedogenic humic acid and consequences for Cd(II), Cu(II) and Pb(II) speciation and bioavailability to green microalga.

    PubMed

    Worms, Isabelle A M; Adenmatten, David; Miéville, Pascal; Traber, Jacqueline; Slaveykova, Vera I

    2015-11-01

    Humic substances (HS) play key role in toxic metal binding and protecting aquatic microorganisms from metal-induced stress. Any environmental changes that could alter HS concentration and reactivity can be expected to modify metal complexation and thus affect metal speciation and bioavailability to microalgae. The present study explores the influence of increased solar irradiance on the chemical structures and molecular weight of Elliott soil humic acid (EHA) and the associated consequences for Cd(II), Cu(II) and Pb(II) complexation and intracellular metal content in microalga. The results demonstrate that high radiance doses induce an oxidation of EHA with a formation of low molecular weight acids, an increase of -OH and -COOH group abundance, and a drop in EHA hydrodynamic size and molecular weight. The photo-induced structural changes are accompanied with a release of metal from M-EHA complexes and narrowing their size distribution, which in turn results in an increase of the intracellular Cd, Cu and Pb contents in microalga Chlamydomonas reinhardtii in agreement with the measured free metal ions concentrations. PMID:25563161

  14. Continuous elimination of Pb2+, Cu2+, Zn2+, H+ and NH4 + from acidic waters by ionic exchange on natural zeolites.

    PubMed

    Calvo, Benjamin; Canoira, Laureano; Morante, Fernando; Martínez-Bedia, José M; Vinagre, Carlos; García-González, Jerónimo-Emilio; Elsen, Jan; Alcantara, Ramon

    2009-07-30

    A study of breakthrough curves for cations usually found in acid mine drainage (Pb(2+), Cu(2+), Zn(2+) and H(+)) and municipal wastewater (NH(4)(+)) have been conducted on some natural zeolitic tuffs. The zeolitic tuffs used in this study are: three zeolitic tuffs from Cayo Formation, Guayaquil (Ecuador), characterized by X-ray diffraction as clinoptilolite (sample CLI-1) and heulandite (samples HEU-1 and HEU-2)-rich tuffs, and two zeolitic tuffs from Parnaiba Basin, Belem do Pará (Brazil), characterized as stilbite-rich tuffs (samples STI-1 and STI-2). The clinoptilolite sample CLI-1 shows an exceedingly good exchange capacities for Pb(2+) and NH(4)(+) as received, and also a very high exchange capacity for Cu(2+) and Zn(2+) when conditioned with 2M sodium chloride, with much higher values than those reported in the literature for other clinioptilolite ores. A general order of effective cation exchange capacity could be inferred from breakthrough curves on these zeolitic tuffs: CLI-1 > HEU-2 > HEU-1 > STI-2. Since it is true for most of the cations studied. PMID:19124201

  15. Effect of EDTA, EDDS, NTA and citric acid on electrokinetic remediation of As, Cd, Cr, Cu, Ni, Pb and Zn contaminated dredged marine sediment.

    PubMed

    Song, Yue; Ammami, Mohamed-Tahar; Benamar, Ahmed; Mezazigh, Salim; Wang, Huaqing

    2016-06-01

    In recent years, electrokinetic (EK) remediation method has been widely considered to remove metal pollutants from contaminated dredged sediments. Chelating agents are used as electrolyte solutions to increase metal mobility. This study aims to investigate heavy metal (HM) (As, Cd, Cr, Cu, Ni, Pb and Zn) mobility by assessing the effect of different chelating agents (ethylenediaminetetraacetic acid (EDTA), ethylenediaminedisuccinic acid (EDDS), nitrilotriacetic acid (NTA) or citric acid (CA)) in enhancing EK remediation efficiency. The results show that, for the same concentration (0.1 mol L(-1)), EDTA is more suitable to enhance removal of Ni (52.8 %), Pb (60.1 %) and Zn (34.9 %). EDDS provides effectiveness to increase Cu removal efficiency (52 %), while EDTA and EDDS have a similar enhancement removal effect on As EK remediation (30.5∼31.3 %). CA is more suitable to enhance Cd removal (40.2 %). Similar Cr removal efficiency was provided by EK remediation tests (35.6∼43.5 %). In the migration of metal-chelate complexes being directed towards the anode, metals are accumulated in the middle sections of the sediment matrix for the tests performed with EDTA, NTA and CA. But, low accumulation of metal contamination in the sediment was observed in the test using EDDS. PMID:26782321

  16. Effect of doping in the Bi-Sr-Ca-Cu-O superconductor

    NASA Technical Reports Server (NTRS)

    Akbar, S. A.; Wong, M. S.; Botelho, M. J.; Sung, Y. M.; Alauddin, M.; Drummer, C. E.; Fair, M. J.

    1991-01-01

    The results of the effect of doping on the superconducting transition in the Bi-Sr-Ca-Cu-O system are reported. Samples were prepared under identical conditions with varying types (Pb, Sb, Sn, Nb) and amounts of dopants. All samples consisted of multiple phases, and showed stable and reproducible superconducting transitions. Stabilization of the well known 110 K phase depends on both the type and amount of dopant. No trace of superconducting phase of 150 K and above was observed.

  17. Adsorption/desorption of Cd(II), Cu(II) and Pb(II) using chemically modified orange peel: Equilibrium and kinetic studies

    NASA Astrophysics Data System (ADS)

    Lasheen, Mohamed R.; Ammar, Nabila S.; Ibrahim, Hanan S.

    2012-02-01

    Waste materials from industries such as food processing may act as cost effective and efficient biosorbents to remove toxic contaminants from wastewater. This study aimed to establish an optimized condition and closed loop application of processed orange peel for metals removal. A comparative study of the adsorption capacity of the chemically modified orange peel was performed against environmentally problematic metal ions, namely, Cd 2+, Cu 2+ and Pb 2+, from aqueous solutions. Chemically modified orange peel (MOP) showed a significantly higher metal uptake capacity compared to original orange peel (OP). Fourier Transform Infrared (FTIR) Spectra of peel showed that the carboxylic group peak shifted from 1637 to 1644 cm -1 after Pb (II) ions binding, indicated the involvement of carboxyl groups in Pb(II) ions binding. The metals uptake by MOP was rapid and the equilibrium time was 30 min at constant temperature and pH. Sorption kinetics followed a second-order model. The mechanism of metal sorption by MOP gave good fits for Freundlich and Langmuir models. Desorption of metals and regeneration of the biosorbent was attained simultaneously by acid elution. Even after four cycles of adsorption-elution, the adsorption capacity was regained completely and adsorption efficiency of metal was maintained at around 90%.

  18. Bioaccessibility versus bioavailability of essential (Cu, Fe, Mn, and Zn) and toxic (Pb) elements from phyto hyperaccumulator Pistia stratiotes: potential risk of dietary intake.

    PubMed

    Čadková, Zuzana; Száková, Jiřina; Miholová, Daniela; Horáková, Barbora; Kopecký, Oldřich; Křivská, Daniela; Langrová, Iva; Tlustoš, Pavel

    2015-03-01

    Aquatic weeds are widely used as animal feed in developing countries. However, information about element bioavailability from these plants is lacking. A combination of an in vitro method [physiologically based extraction test (PBET)] and an in vivo feeding trial was used in this study to investigate potential element bioaccessibility and estimated bioavailability of Pistia stratiotes (PS). Cu, Fe, Mn, Zn, and Pb concentrations in PS biomass, artificial gastrointestinal fluids, and rat tissues were determined using atomic absorption spectrometry with electrothermal atomization and inductively coupled plasma-atomic emission spectrometry. PS exhibited elevated Fe, Mn, and Pb levels. The PBET revealed high bioaccessibility of all monitored elements from PS biomass. The results of the in vivo trial were inconsistent with those of the PBET, because animals fed PS exhibited low levels of essential elements in the tissues. The consumption of a PS-supplemented diet significantly decreased total Fe levels and increased the total level of accumulation of Pb in exposed animals. Significantly reduced amounts of essential elements in the intestinal walls indicated a potential disruption in nutrient gastrointestinal absorption in animals fed PS. PMID:25664561

  19. The synthesis and characterization of Ti/SnO 2-Sb 2O 3/PbO 2 electrodes: The influence of morphology caused by different electrochemical deposition time

    NASA Astrophysics Data System (ADS)

    An, Hao; Li, Qin; Tao, Dejing; Cui, Hao; Xu, Xiaotian; Ding, Liang; Sun, Li; Zhai, Jianping

    2011-10-01

    For the electrochemical oxidative degradation of wastewater, it is crucial for electrodes to be highly catalytic active, stable in performance and inexpensive in price. This study focuses on the preparation of the Ti/SnO 2-Sb 2O 3/PbO 2 anodes by anodic deposition under galvanostatic conditions and their electrocatalytic activity affected by crystal structure and surface roughness under different electrochemical deposition time, with phenol taken as the model pollutant to evaluate the electrocatalytic activity. The electrode surface morphology is characterized by XRD and SEM-EDX. The treatment effect of phenol is reflected by electrochemical analysis like CV and LSV. An important conclusion from experiment is that electrochemical deposition time has a major impact on electrocatalytic activity with the optimal deposition time observed around 30 min. At both deposition time beyond this optimal time window, electrocatalytic activity of phenol is substantially lowered. Increasing in electrochemical deposition time leads to a more uniform and smooth electrode surface, which enjoys a more compact structure than the "cracked-mud" one but lower specific surface area and catalytic activity. On the contrary, the "cracked-mud" structure means potentially a unique porous structure, which makes morphology at 30 min a perfect one for high electrocatalytic activity.

  20. High-pressure synthesis of LiTi MF 6 ( M = Mn, Fe, Co, Ni) with trirutile, Na 2SiF 6, and PbSb 2O 6 structures

    NASA Astrophysics Data System (ADS)

    Sekino, Tohru; Endo, Tadashi; Sato, Tsugio; Shimada, Masahiko

    1990-10-01

    High- and low-pressure forms of LiTi M2+F 6 ( M2 = Mn, Fe, Co, and Ni) were prepared by the reaction of LiF, TiF 3, and MF 2 under conditions of 1.5-7.0 GPa and 700-1200°C. All the low-pressure phases belonged to a trirutile structure. On the other hand, the high-pressure phases crystallized in a Na 2SiF 6-type structure for M2+ = Mn and a PbSb 2O 6-type structure for M2+ = Fe, Co, and Ni. According to the Rietveld analysis, it was observed that such structures were basically described as hexagonal close packing of F - ions with cations placed in half of the octahedral sites, but involved a significant difference in cationic proportions at the z = 0 and {1}/{2} levels. Detailed structure data of high- and low-pressure phases are included in the present paper, and the structural stability of each phase is discussed relative to the synthetic P T conditions.

  1. Determination of traces of As, B, Bi, Ga, Ge, P, Pb, Sb, Se, Si and Te in high-purity nickel using inductively coupled plasma-optical emission spectrometry (ICP-OES).

    PubMed

    Thangavel, S; Dash, K; Dhavile, S M; Sahayam, A C

    2015-01-01

    A method has been developed for the determination of traces of arsenic, boron, bismuth, gallium, germanium, phosphorus, lead, antimony, selenium, silicon and tellurium in nickel matrix. The sample was dissolved in HClO4 (~ 150°C) and nickel was settled as crystalline nickelperchlorate [Ni(ClO4)2] on cooling. The mixture was ultrasonicated and after the separation of Ni(ClO4)2, analytes of interest were determined in the supernatant using ICP-OES. Similarly, it was also found that, after the dissolution of nickel in perchloric acid, when the solution temperature was maintained at ~ 100°C, long needle like crystals of nickel perchlorate were formed. The crystals were separated from the mixture and trace elements in the supernatant were determined using ICP-OES. In both methods the matrix removal was >99% and the recoveries of analytes were in the range 92-97%. The limits of detection for As, B, Bi, Ga, Ge, P, Pb, Sb, Se, Si and Te were found to be 0.18, 0.21, 0.07, 0.06, 0.25, 0.11, 0.09, 0.10, 0.17, 0.20 and 0.07 μg g(-1) respectively. The procedure was applied for the analysis of a standard reference material nickel oxide (SRM 761, Nickel Oxide No.1, NBS, USA) and the values obtained are in close agreement with the certified values. PMID:25281133

  2. Effects of K doping on structural and superconducting properties of Bi{sub 1.5}Pb{sub 0.5}Sr{sub 1.8}CaCu{sub 2}O{sub 8+δ} compounds

    SciTech Connect

    Belala, K; Mosbah, M. F.

    2013-12-16

    Two kinds of potassium doped Bi(Pb)2212 samples are used to investigate the effect of doping the Bi(Pb)2212 ((Bi,Pb){sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}) phase by potassium (K): In the first one K is substituted on the Sr site; In the second one K is added. Using the solid state method reaction samples of Bi{sub 1.5}Pb{sub 0.5}(Sr{sub 1.8−x}K{sub x})CaCu{sub 2}O{sub 8+d} and Bi{sub 1.5}Pb{sub 0.5}Sr{sub 1.8}CaCu{sub 2}O{sub 8+d}K{sub x} (0 ≤ x≤ 0.05) have been prepared from powders of carbonates and primary oxides having purity over 99%. The samples have been characterized by X ray diffraction (XRD), scanning electron microscopy (SEM) and resistivity versus temperature measurements. Results show how the kind and the rate of doping by potassium affects the structural and transport properties of Bi(Pb)2212 phase.

  3. Accumulation of as, pb, and cu associated with the recent sedimentary processes in the colorado delta, South of the United States-Mexico boundary.

    PubMed

    Daesslé, L W; Lugo-Ibarra, K C; Tobschall, H J; Melo, M; Gutiérrez-Galindo, E A; García-Hernández, J; Alvarez, L G

    2009-05-01

    Sediment cores from the Colorado River (CR) remnant delta were used to assess the changing sedimentation and pollutant deposition processes in response to extensive human manipulation of the river. The cores are formed of alternating layers of clays and silts, with isolated sandy horizons. The clayey units are interpreted as periods of flood flows into this low gradient and meandering estuary after dam construction in the United States. The geochemistry of these sediments is particular because of the association of MnO with CaO rather than with the Fe(2)O(3)-rich clays. Past pollution of the CR delta by As, and probably also Pb and Cu, is recorded in some cores. Enrichment factors (EFs) >1 for these elements and their statistical association suggest anthropogenic inputs. The most likely sources for these element enrichments (especially As) are the arsenate-based pesticides used intensively in the area during the first half of the 20th century. The transport of these elements from the nearby agricultural lands into the present river reaches appears to have been driven in part by flooding events of the CR. Flushing by river and tide flows appear to be responsible of a lower pollutant deposition in the CR compared to the adjacent Hardy River (HR). Arsenic in the buried clay units of the HR has concentrations above the probable toxic effect level (PEL) for dwelling organisms, with maximum concentrations of 30 microg g(-1). Excess (210)Pb activities ((210)Pb(xs)) indicate that fluxes of this unsupported atmospheric isotope were not constant in this estuarine environment. However, the presence of (210)Pb(xs) does indicate that these sediments accumulated during the last ~100 years. Aproximate sediment ages were estimated from the correlation of historic flooding events with the interpretation of the stratigraphic record. They are in fair agreement with the reported onset of DDT metabolites at the bottom of one core. PMID:18797954

  4. Determination of water-soluble and insoluble (dilute-HCl-extractable) fractions of Cd, Pb and Cu in Antarctic aerosol by square wave anodic stripping voltammetry: distribution and summer seasonal evolution at Terra Nova Bay (Victoria Land).

    PubMed

    Annibaldi, A; Truzzi, C; Illuminati, S; Bassotti, E; Scarponi, G

    2007-02-01

    Eight PM10 aerosol samples were collected in the vicinity of the "Mario Zucchelli" Italian Antarctic Station (formerly Terra Nova Bay Station) during the 2000-2001 austral summer using a high-volume sampler and precleaned cellulose filters. The aerosol mass was determined by differential weighing of filters carried out in a clean chemistry laboratory under controlled temperature and humidity. A two-step sequential extraction procedure was used to separate the water-soluble and the insoluble (dilute-HCl-extractable) fractions. Cd, Pb and Cu were determined in the two fractions using an ultrasensitive square wave anodic stripping voltammetric (SWASV) procedure set up for and applied to aerosol samples for the first time. Total extractable metals showed maxima at midsummer for Cd and Pb and a less clear trend for Cu. In particular, particulate metal concentrations ranged as follows: Cd 0.84-9.2 microg g(-1) (average 4.7 microg g(-1)), Pb 13.2-81 microg g(-1) (average 33 microg g(-1)), Cu 126-628 microg g(-1) (average 378 microg g(-1)). In terms of atmospheric concentration, the values were: Cd 0.55-6.3 pg m(-3) (average 3.4 pg m(-3)), Pb 8.7-48 pg m(-3) (average 24 pg m(-3)), Cu 75-365 pg m(-3) (average 266 pg m(-3)). At the beginning of the season the three metals appear widely distributed in the insoluble (HCl-extractable) fraction (higher proportions for Cd and Pb, 90-100%, and lower for Cu, 70-90%) with maxima in the second half of December. The soluble fraction then increases, and at the end of the season Cd and Pb are approximately equidistributed between the two fractions, while for Cu the soluble fraction reaches its maximum level of 36%. Practically negligible contributions are estimated for crustal and sea-spray sources. Low but significant volcanic contributions are estimated for Cd and Pb (approximately 10% and approximately 5%, respectively), while there is an evident although not quantified marine biogenic source, at least for Cd. The estimated natural

  5. Historical perspective of heavy metals contamination (Cd, Cr, Cu, Hg, Pb, Zn) in the Seine River basin (France) following a DPSIR approach (1950-2005).

    PubMed

    Meybeck, Michel; Lestel, Laurence; Bonté, Philippe; Moilleron, Régis; Colin, Jean Louis; Rousselot, Olivier; Hervé, Daniel; de Pontevès, Claire; Grosbois, Cécile; Thévenot, Daniel R

    2007-04-01

    The Driver-Pressures-State-Impact-Response approach is applied to heavy metals in the Seine River catchment (65,000 km(2); 14 million people of which 10 million are aggregated within Paris megacity; 30% of French industrial and agricultural production). The contamination pattern at river mouth is established on the particulate material at different time scales: 1930-2000 for floodplain cores, 1980-2003 for suspended particulate matter (SPM) and bed-sediments, 1994-2003 for atmospheric fallout and annual flood deposits. The Seine has been among the most contaminated catchments with maximum contents recorded at 130 mg kg(-1) for Cd, 24 for Hg, 558 for Pb, 1620 for Zn, 347 for Cu, 275 for Cr and 150 for Ni. Today, the average levels for Cd (1.8 mg kg(-1)), Hg (1.08), Pb (108), Zn (370), Cu (99), Cr (123) and Ni (31) are much lower but still in the upper 90% of the global scale distribution (Cr and Ni excepted) and well above the natural background values determined on pre-historical deposits. All metal contents have decreased at least since 1955/65, well before metal emission regulations that started in the mid 1970's and the metal monitoring in the catchment that started in the early 1980's. In the last 20 y, major criteria changes for the management of contaminated particulates (treated urban sludge, agricultural soils, dredged sediments) have occurred. In the mid 1990's, there was a complete shift in the contamination assessment scales, from sediment management and water usage criteria to the good ecological state, now required by the 2000 European Directive. When comparing excess metal outputs, associated to river SPM, to the average metal demand within the catchment from 1950 to 2000, the leakage ratios decrease exponentially from 1950 to 2000 for Cd, Cr, Cu, Pb and Zn, meanwhile, a general increase of the demand is observed: the rate of recycling and/or treatment of metals within the anthroposphere has been improved ten-fold. Hg environmental trajectory is very

  6. Chemical fractionation of Cu, Zn, Cd, Cr, and Pb in sewage sludge amended soils at the end of 65-d sorghum-sudan grass growth.

    PubMed

    Sivapatham, Paramasivam; Lettimore, Jon M; Alva, Ashok K; Jayaraman, Kuppuswamy; Harper, Legia M

    2014-09-19

    Heavy metals are potentially toxic to human life and the environment. Metal toxicity depends on chemical associations in soil. Understanding the chemical association of trace elements in soils amended with biosolids is very important since it determines their availability within rhizosphere and mobility beyond the rhizosphere. A sequential extraction method was used to determine the various chemical associations [labile (exchangeable + sorbed), organic, carbonates, and sulfides] of Cu, Zn, Cd, Cr, and Pb at the end of sorghum-sudan grass growth (65d) in Candler fine sand (pH = 6.8) and in Ogeechee loamy sand (pH = 5.2) amended with wastewater treatment sludge (WWTS) obtained from two different sources at application rates of 0, 24.7, 49.4, 98.8, and 148.2 Mg ha(-1). Results of this study indicated that irrespective of the soil type, Cu, Cd, Cr, and Pb in the labile fractions (exchangeable + sorbed) were in the range of 0-3.0 mg kg(-1) and the amount for Zn was in the range of 0.2-6.6 mg kg(-1). Therefore, their availability to plants and mobility beyond rhizosphere would be substantially low unless further transformations occur from other fractions. Results also indicated that the presence of substantial amounts of trace elements studied were in sulfide (HNO3) fraction and in organic (NaOH) fraction irrespective of soil type with the exception of Pb which was mainly present as carbonate (Na2EDTA) fraction and the remaining Pb equally as sulfide (HNO3) and organic (NaOH) fractions. Furthermore, results indicated that Cd was mainly present as carbonate (Na2EDTA) fraction. Irrespective of soil type, source and rate of WWTS application, summation of quantities of various fractions of all the trace elements studied through sequential extraction procedure were 1 to 25 % lower than that of total recoverable quantities of these trace elements determined on acid digestion described by US EPA method 3050 B. It was further evident that growing sorghum sudan grass for 65-d

  7. Superconducting Bi1.5Pb0.5Sr2Ca2Cu3O(x) ceramics by rapid melt quenching and glass crystallization

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.

    1989-01-01

    A glass of nominal Bi(1.5)Pb(0.5)Sr2Ca2Cu3O(x) composition, prepared by rapid quenching of the melt, showed a glass transition temperature of 383 C, crystallization temperature of 446 C, melting temperature of 855 C, and bulk density of 5.69 g/cu cm in air. The activation energy for crystallization of the glass was estimated to be 292kJ/mol from non-isothermal DSC. On heating in oxygen, the glass showed a slow and continuous weight gain starting at approximately 530 C which reached a plateau at approximately 820 C. The weight gained during heating was retained on cooling to ambient conditions indicating an irreversible oxidation step. The influence of annealing conditions on the formation of various phases in the glass has been investigated. The Bi(2)Sr(2)Ca(0)Cu(1)O(6) phase crystallized out first followed by formation of other phases at higher temperatures. The high-T(sub c) phase, isostructural with Bi(2)Sr(2)Ca(2)Cu(3)O(10) was not detected below 840 C, but its fraction increased with the annealing time at 840 C. A sample annealed at 840 C for 243h in air and furnace cooled showed the highest T(sub c)(R=0) of 107.2K and a narrow transition width, delta T(sub c)(10 to 90 percent), of approximately 2 K. The high T(sub c) phase does not seem to crystallize out directly from the glass but is rather produced at high temperature by reaction between the phases formed at lower temperatures. The kinetics of 110K phase formation was sluggish. It appears that the presence of lead helps in the formation and/or stabilization of the 110 K phase.

  8. In situ measurement of electromigration-induced transient stress in Pb-free Sn-Cu solder joints by synchrotron radiation based x-ray polychromatic microdiffraction

    NASA Astrophysics Data System (ADS)

    Chen, Kai; Tamura, N.; Kunz, M.; Tu, K. N.; Lai, Yi-Shao

    2009-07-01

    Electromigration-induced hydrostatic elastic stress in Pb-free SnCu solder joints was studied by in situ synchrotron x-ray white beam microdiffraction. The elastic stresses in two different grains with similar crystallographic orientation, one located at the anode end and the other at the cathode end, were analyzed based on the elastic anisotropy of the β-Sn crystal structure. The stress in the grain at the cathode end remained constant except for temperature fluctuations, while the compressive stress in the grain at the anode end was builtup as a function of time during electromigration until a steady state was reached. The measured compressive stress gradient between the cathode and the anode is much larger than what is needed to initiate Sn whisker growth. The effective charge number of β-Sn derived from the electromigration data is in good agreement with the calculated value.

  9. Ideal Weyl Semimetals in the Chalcopyrites CuTlSe2 , AgTlTe2 , AuTlTe2 , and ZnPbAs2

    NASA Astrophysics Data System (ADS)

    Ruan, Jiawei; Jian, Shao-Kai; Zhang, Dongqin; Yao, Hong; Zhang, Haijun; Zhang, Shou-Cheng; Xing, Dingyu

    2016-06-01

    Weyl semimetals are new states of matter which feature novel Fermi arcs and exotic transport phenomena. Based on first-principles calculations, we report that the chalcopyrites CuTlSe2 , AgTlTe2 , AuTlTe2 , and ZnPbAs2 are ideal Weyl semimetals, having largely separated Weyl points (˜0.05 Å-1 ) and uncovered Fermi arcs that are amenable to experimental detections. We also construct a minimal effective model to capture the low-energy physics of this class of Weyl semimetals. Our discovery is a major step toward a perfect playground of intriguing Weyl semimetals and potential applications for low-power and high-speed electronics.

  10. AC losses in BiPbSrCaCuO-2223/Ag multifilamentary tapes in conditions similar to those in superconducting transmission lines

    NASA Astrophysics Data System (ADS)

    Majoros, M.; Glowacki, B. A.; Campbell, A. M.; Han, Z.; Vase, P.

    1998-12-01

    Transport AC losses in BiPbSrCaCuO-2223/Ag multifilamentary tape with 19 filaments were measured. The sample was 1.05 m long, wound in form of a helix with a gap between the tapes comparable with the tape width. Two different types of potential leads-tape following, axis following-with taps positioned in the centre of the tape were mounted on inner as well as outer surface of the helical sample. AC losses were measured at power frequencies by an electrical method using a lock-in nanovoltmeter. The influence of potential wires arrangement and the potential taps position on measured AC loss level and its frequency dependence was analysed.

  11. Flux patterns of multifilamentary Ag-sheathed (Pb,Bi)2Sr2Ca2Cu3O10+δ tapes

    NASA Astrophysics Data System (ADS)

    Koblischka, M. R.; Johansen, T. H.; Bratsberg, H.; Půst, L.; Galkin, A.; Nálevka, P.; Maryško, M.; Jirsa, M.; Bentzon, M.; Bodin, P.; Vase, P.; Freltoft, T.

    1998-06-01

    Flux patterns of multifilamentary Ag-sheathed (Pb,Bi)2Sr2Ca2Cu3O10+δ tapes comprising 19 filaments are visualized by means of magneto-optic imaging. In low fields, the shielding currents are seen to flow mainly in the outermost filaments. With increasing external magnetic field, the inner filaments also contribute to the current flow. To compare the local flux distribution with the integral magnetization values, magnetization loops are measured by a SQUID magnetometer on the same sample following the fields used in the magneto-optic imaging (± 120 mT) and covering fields up to ±5 T at various temperatures. The magnetization loops also reveal that the multifilamentary tapes show the anomalous position of the central peak, but always less pronounced than in monofilamentary tapes.

  12. Ideal Weyl Semimetals in the Chalcopyrites CuTlSe_{2}, AgTlTe_{2}, AuTlTe_{2}, and ZnPbAs_{2}.

    PubMed

    Ruan, Jiawei; Jian, Shao-Kai; Zhang, Dongqin; Yao, Hong; Zhang, Haijun; Zhang, Shou-Cheng; Xing, Dingyu

    2016-06-01

    Weyl semimetals are new states of matter which feature novel Fermi arcs and exotic transport phenomena. Based on first-principles calculations, we report that the chalcopyrites CuTlSe_{2}, AgTlTe_{2}, AuTlTe_{2}, and ZnPbAs_{2} are ideal Weyl semimetals, having largely separated Weyl points (∼0.05  Å^{-1}) and uncovered Fermi arcs that are amenable to experimental detections. We also construct a minimal effective model to capture the low-energy physics of this class of Weyl semimetals. Our discovery is a major step toward a perfect playground of intriguing Weyl semimetals and potential applications for low-power and high-speed electronics. PMID:27314733

  13. Development, validation and accreditation of a method for the determination of Pb, Cd, Cu and As in seafood and fish feed samples.

    PubMed

    Psoma, A K; Pasias, I N; Rousis, N I; Barkonikos, K A; Thomaidis, N S

    2014-05-15

    A rapid, sensitive, accurate and precise method for the determination of Pb, Cd, As and Cu in seafood and fish feed samples by Simultaneous Electrothermal Atomic Absorption Spectrometry was developed in regard to Council Directive 333/2007EC and ISO/IEC 17025 (2005). Different approaches were investigated in order to shorten the analysis time, always taking into account the sensitivity. For method validation, precision (repeatability and reproducibility) and accuracy by addition recovery tests have been assessed as performance criteria. The expanded uncertainties based on the Eurachem/Citac Guidelines were calculated. The method was accredited by the Hellenic Accreditation System and it was applied for an 8 years study in seafood (n=202) and fish feeds (n=275) from the Greek market. The annual and seasonal variation of the elemental content and correlation among the elemental content in fish feeds and the respective fish samples were also accomplished. PMID:24423504

  14. In situ measurement of electromigration-induced transient stress in Pb-free Sn-Cu solder joints by synchrotron radiation based X-ray polychromatic microdiffraction

    SciTech Connect

    Chen, Kai; Tamura, Nobumichi; Kunz, Martin; Tu, King-Ning; Lai, Yi-Shao

    2009-05-15

    Electromigration-induced hydrostatic elastic stress in Pb-free SnCu solder joints was studied by in situ synchrotron X-ray white beam microdiffraction. The elastic stresses in two different grains with similar crystallographic orientation, one located at the anode end and the other at the cathode end, were analyzed based on the elastic anisotropy of the {beta}-Sn crystal structure. The stress in the grain at the cathode end remained constant except for temperature fluctuations, while the compressive stress in the grain at the anode end was built-up as a function of time during electromigration until a steady state was reached. The measured compressive stress gradient between the cathode and the anode is much larger than what is needed to initiate Sn whisker growth. The effective charge number of {beta}-Sn derived from the electromigration data is in good agreement with the calculated value.

  15. In situ measurement of electromigration-induced transient stress in Pb-free Sn-Cu solder joints by synchrotron radiation based X-ray polychromatic microdiffraction

    SciTech Connect

    Chen, Kai; Tamura, Nobumichi; Kunz, Martin; Tu, King-Ning; Lai, Yi-Shao

    2009-12-01

    Electromigration-induced hydrostatic elastic stress in Pb-free SnCu solder joints was studied by in situ synchrotron X-ray white beam microdiffraction. The elastic stresses in two different grains with similar crystallographic orientation, one located at the anode end and the other at the cathode end, were analyzed based on the elastic anisotropy of the Beta-Sn crystal structure. The stress in the grain at the cathode end remained constant except for temperature fluctuations, while the compressive stress in the grain at the anode end was built-up as a function of time during electromigration until a steady state was reached. The measured compressive stress gradient between the cathode and the anode is much larger than what is needed to initiate Sn whisker growth. The effective charge number of Beta-Sn derived from the electromigration data is in good agreement with the calculated value.

  16. RAPID COMMUNICATION: Radio frequency response of Ag-sheathed (Bi, Pb)2Sr2Ca2Cu3O10+x superconducting tapes

    NASA Astrophysics Data System (ADS)

    Grasso, G.; Malagoli, A.; Scati, N.; Guasconi, P.; Roncallo, S.; Siri, A. S.

    2000-10-01

    The response of long (Bi,Pb)2Sr2Ca2Cu3O10 conductors fabricated by the oxide-powder-in-tube method to a radio frequency excitation was investigated while employed as the inductive part of large L-C resonating circuits. After removal of the outer silver sheath, superconducting devices cooled down to 77 K showed superior properties compared to equivalent non-superconducting circuits: Bi-based resonators, conceived for a working frequency in the range between 5 and 17 MHz, presented an improvement of the quality factor by a factor of 20. This result opens new perspectives for the application of Bi-based superconducting materials in the detection of a weak radio frequency signal, as in magnetic resonance imaging.

  17. Effect of neutron irradiation on the London penetration depth for polycrystalline Bi(1.8)Pb(0.3)Sr2Ca2Cu3O10 superconductor

    NASA Technical Reports Server (NTRS)

    Ossandon, J. G.; Thompson, J. R.; Sun, Yang Ren; Christen, D. K.; Chakoumakos, B. C.

    1995-01-01

    Magnetization studies of polycrystalline Bi(1.8)Pb(0.3)Sr2Ca2Cu3O10 superconductor, prior to and after neutron irradiation, showed an increase in J(sub c) due to irradiation damage. Analysis of the equilibrium magnetization revealed significant increases in other more fundamental properties. In particular, the London penetration depth increased by approximately 15 percent following irradiation with 8 x 10(exp 16) neutrons/sq cm. Corresponding changes were observed in the upper critical magnetic field H(sub c2). However, the most fundamental thermodynamic property, the superconductive condensation energy F(sub c), was unaffected by the moderate level of neutron-induced damage.

  18. Charged particle multiplicity in sup 28 Si+Al, Cu, and Pb reactions at E sub lab =14. 6 GeV/nucleon

    SciTech Connect

    Barrette, J.; Bellwied, R.; Braun-Munzinger, P.; Cleland, W.E.; David, G.; Dietzsch, O.; Duek, E.; Fatyga, M.; Fox, D.; Greene, S.V.; Hall, J.R.; Heifetz, R.; Hemmick, T.K.; Herman, M.; Hermann, N.; Hogue, R.W.; Ingold, G.; Jayananda, K.; Kraus, D.; Kumar, S.; Lacasse, R.; Lissauer, D.; Llope, W.J.; Ludlam, T.; Majka, R.; Makowiecki, D.; Mark, S.K.; McCorkle, S.R.; Mitchell, J.T.; Muthuswamy, M.; O'Brien, E.; Olsen, L.; Polychronakos, V.; Pruneau, C.; Rawool-Sullivan, M.; Rotondo, F.; Sandweiss, J.; Simon-Gillo, J.; Sonnadara, U.; Stachel, J.; Sullivan, J.P.; Sunier, J.; Takagui, E.M.; Takai, H.; Throwe, T.; van Hecke, H.; Waters, L.; Wolf, K.; Wolfe, D.; Woody, C.L.; Xu, N.; Zhang, Z. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 McGill University, Montreal, H3A 2T8 University of New Mexico, Albuquerque, New Mexico 87131 University of Pittsburgh, Pittsburgh,

    1992-07-01

    Collisions of {sup 28}Si+Al, Cu, and Pb at {ital E}{sub lab}=14.6 GeV/nucleon were studied at the Brookhaven National Laboratory Alternating Gradient Synchrotron. Charged particle multiplicity was measured over the pseudorapidity interval 0.875{le}{eta}{le}3.86 with a silicon pad detector. A strong correlation is seen between the multiplicity and the transverse energy measured in the interval {minus}0.5{le}{eta}{le}0.8. Correlation with the energy going forward after the collision and comparison with calculations indicate that rescattering is required to explain the data. The data are compared under the assumption of Koba-Nielson-Olesen scaling. The measured multiplicity scales approximately with the total number of participant nucleons and less well with the available center-of-mass kinetic energy.

  19. Mixture toxicity and tissue interactions of Cd, Cu, Pb and Zn in earthworms (Oligochaeta) in laboratory and field soils: a critical evaluation of data.

    PubMed

    Weltje, L

    1998-05-01

    Soil organisms inhabiting contaminated field sites are usually exposed to mixtures of toxicants. In such mixtures, toxicants can interact to express enhanced or weakened toxicity. Therefore, mixture effects should be considered in risk assessment methods for polluted soils. Data on mixture toxicity to soil organisms are scarce, however. In this paper, data on sublethal toxicity and tissue concentrations of Cd. Cu, Pb and Zn mixtures in earthworms are evaluated and compared with data on other organisms. Toxic effects were mainly antagonistic for total soil concentrations and nearly concentration-additive for 0.01 M CaCl2-extractable soil concentrations. Evidence to support concentration-additive behaviour of metals was found in interaction patterns within earthworm tissues. A method is proposed to assess the sublethal toxicity of metal mixtures in field soils to earthworms, based on single metal experiments from the laboratory. Finally, suggestions are made on how to incorporate mixture toxicity in risk assessment for polluted soils. PMID:9570111

  20. Lead-Halide Perovskite Solar Cells by CH3NH3I Dripping on PbI2-CH3NH3I-DMSO Precursor Layer for Planar and Porous Structures Using CuSCN Hole-Transporting Material.

    PubMed

    Ito, Seigo; Tanaka, Soichiro; Nishino, Hitoshi

    2015-03-01

    The sequential fabrication scheme of the CH3NH3PbI3 layer has been improved to fabricate planar-structure CH3NH3PbI3 perovskite solar cells using CuSCN hole-transporting material (HTM). In the PbI2 layer fabricated by the spin-coating method, at first, small amounts of CH3NH3I (MAI) and DMSO were incorporated as the first-drip precursor layer on a flat TiO2 layer. On the first-drip precursor layers, an MAI solution was applied by either soaking (MAI-soaking method) or dripping using successive spin coating (MAI-dripping). The morphology and crystal transformations were observed by SEM and XRD, respectively. Using the normal sequential MAI-soaking method, we were unable to fabricate planar CH3NH3PbI3 perovskite solar cells with CuSCN HTM. Using the MAI-dripping method, however, a significant photovoltaic effect has been observed to be planar PbI3 perovskite/CuSCN> solar cells. PMID:26262667

  1. Measurement of inclusive spectra of protons emitted in interactions between /sup 12/C nuclei of energy 3. 6 GeV/nucleon and C, Cu, Sn, and Pb nuclei

    SciTech Connect

    Ad'yasevich, B.P.; Antonenko, V.G.; Vinogradov, A.A.; Grigor'yan, Y.I.; Ippolitov, M.S.; Karadzhev, K.V.; Lebedev, A.L.; Man'ko, V.I.; Nikolaev, S.A.; Polunin, Y.P.; Tsvetkov, A.A.

    1984-08-01

    The inclusive spectra of protons emitted when carbon ions of energy 3.6 GeV/nucleon are used to bombard C, Cu, Sn, and Pb targets are investigated. Data are presented on the invariant cross sections for proton emission in a wide range of emission angles and momenta. The observed empirical relations are discussed.

  2. 210Po Activity and concentrations of selected trace elements (As, Cd, Cu, Hg, Pb, Zn) in the muscle tissue of tunas Thunnus albacares and Katsuwonus pelamis from the Eastern Pacific Ocean.

    PubMed

    Ruelas-Inzunza, Jorge; Soto-Jiménez, Martín Federico; Ruiz-Fernández, Ana Carolina; Bojórquez-Leyva, Humberto; Pérez-Bernal, Hascibe; Páez-Osuna, Federico

    2012-12-01

    Daily mineral intake (DMI) of Cu and Zn, percentage weekly intake (PWI) of As, Cd, Hg, Pb, and doses of (210)Po were estimated by using their elemental concentration in muscle of two tuna species and the average tuna consumption in Mexico. Skipjack tuna Katsuwonus pelamis had significantly (p < 0.05) higher levels of As (1.38 μg g(-1) dw) and Cu (1.85 μg g(-1) dw) than yellowfin tuna Thunnus albacares, whereas Pb concentrations (0.18 μg g(-1) dw) were significantly (p < 0.05) higher in T. albacares. The sequence of elemental concentrations in both species was Zn > Cu > As > Hg > Pb > Cd. In T. albacares, concentrations of Cd and Pb in muscle tissue were positively correlated (p < 0.05) with weight of specimens, while Cu was negatively correlated. DMI values were below 10 %. PWI figures (<2 %) are not potentially harmful to human health. (210)Po concentration in T. albacares and K. pelamis accounts for 13.5 to 89.7 % of the median individual annual dose (7.1 μSv) from consumption of marine fish and shellfish for the world population. PMID:22684512

  3. Interaction effects of multi-metal solutions (As, Cr, Cu, Ni, Pb and Zn) on life history traits in the rotifer Plationus patulus.

    PubMed

    Ríos-Arana, Judith V; Walsh, Elizabeth J; Ortiz, Melchor

    2007-08-01

    While many studies have determined toxicity of single heavy metals, few have addressed the combined effects of multiple elements at different concentrations. In order to estimate how metal mixtures affect population dynamics of freshwater rotifers, we exposed Plationus patulus to environmentally relevant concentrations and combinations of arsenic and five heavy metals (Cr, Cu, Ni, Pb and Zn) for 8 days. The life-history parameters, intrinsic rate of increase (r), relative cumulative reproduction (RCR), mortality ratio, mictic ratio, fertilization ratio, and number of deformed offspring were used as endpoints. Exposures were repeated 4 times and considered as blocks in the experimental design. Differences between treatments were evaluated through ANOVA and LSD mean analysis. The combined presence of As, Cu, Ni, Pb, and Zn in different concentrations produced a variety of changes in the population dynamics of P. patulus. However, only Cr produced a significant element*environment interaction. The presence of Cr leads to significant decreases in the intrinsic rate of increase and increased mortality ratio in multi-metal environments. The population growth (as r) decreased from 0.25 to -0.16 due to Cr (10 microg/L) interaction with the remaining elements, and values 0.16-0.12 were observed in treatments containing high levels (50 microg/L) of Cr. Mortality ratio increased from 0.066 to 0.822 due to Cr (10 and 50 microg/L) interactions with the remaining elements at high concentrations. Responses of this basal consumer to metal mixtures will provide insights into how aquatic food webs and their constituent organisms can be altered by anthropogenic inputs like heavy metal contamination. PMID:17680488

  4. Removal of divalent heavy metals (Cd, Cu, Pb, and Zn) and arsenic(III) from aqueous solutions using scoria: kinetics and equilibria of sorption.

    PubMed

    Kwon, Jang-Soon; Yun, Seong-Taek; Lee, Jong-Hwa; Kim, Soon-Oh; Jo, Ho Young

    2010-02-15

    Kinetic and equilibrium sorption experiments were conducted on removal of divalent heavy metals (Pb(II), Cu(II), Zn(II), Cd(II)) and trivalent arsenic (As(III)) from aqueous solutions by scoria (a vesicular pyroclastic rock with basaltic composition) from Jeju Island, Korea, in order to examine its potential use as an efficient sorbent. The removal efficiencies of Pb, Cu, Zn, Cd, and As by the scoria (size=0.1-0.2mm, dose=60gL(-1)) were 94, 70, 63, 59, and 14%, respectively, after a reaction time of 24h under a sorbate concentration of 1mM and the solution pH of 5.0. A careful examination on ionic concentrations in sorption batches suggested that sorption behaviors of heavy metals onto scoria are mainly controlled by cation exchange. On the other hand, arsenic appeared to be sensitive to specific sorption onto hematite (a minor constituent of scoria). Equilibrium sorption tests indicated that the removal efficiency for heavy metals increases with increasing pH of aqueous solutions, which is resulted from precipitation as hydroxides. Similarly, multi-component systems containing heavy metals and arsenic showed that the arsenic removal increases with increasing pH of aqueous solutions, which can be attributed to coprecipitation with metal hydroxides. The empirically determined sorption kinetics were well fitted to a pseudo-second order model, while equilibrium sorption data for heavy metals and arsenic onto scoria were consistent with the Langmuir and Freundlich isotherms, respectively. Natural scoria studied in this work is an efficient sorbent for concurrent removal of divalent heavy metals and arsenic. PMID:19828237

  5. Development and validation of a laser-induced breakdown spectroscopic method for ultra-trace determination of Cu, Mn, Cd and Pb metals in aqueous droplets after drying.

    PubMed

    Aras, Nadir; Yalçın, Şerife

    2016-03-01

    The present study reports a fast and accurate methodology for laser-induced breakdown spectroscopic, LIBS, analysis of aqueous samples for environmental monitoring purposes. This methodology has two important attributes: one is the use of a 300nm oxide coated silicon wafer substrate (Si+SiO2) for the first time for manual injection of 0.5 microliter aqueous metal solutions, and two is the use of high energy laser pulses focused outside the minimum focus position of a plano convex lens at which relatively large laser beam spot covers the entire droplet area for plasma formation. Optimization of instrumental LIBS parameters like detector delay time, gate width and laser energy has been performed to maximize atomic emission signal of target analytes; Cu, Mn, Cd and Pb. Under the optimal conditions, calibration curves were constructed and enhancements in the LIBS emission signal were obtained compared to the results of similar studies given in the literature. The analytical capability of the LIBS technique in liquid analysis has been improved. Absolute detection limits of 1.3pg Cu, 3.3pg Mn, 79pg Cd and 48pg Pb in 0.5 microliter volume of droplets were obtained from single shot analysis of five sequential droplets. The applicability of the proposed methodology to real water samples was tested on the Certified Reference Material, Trace Metals in Drinking Water, CRM-TMDW and on ICP multi-element standard samples. The accuracy of the method was found at a level of minimum 92% with relative standard deviations of at most 20%. Results suggest that 300nm oxide coated silicon wafer has an excellent potential to be used as a substrate for direct analysis of contaminants in water supplies by LIBS and further research, development and engineering will increase the performance and applicability of the methodology. PMID:26717813

  6. Build-up and wash-off dynamics of atmospherically derived Cu, Pb, Zn and TSS in stormwater runoff as a function of meteorological characteristics.

    PubMed

    Murphy, Louise U; Cochrane, Thomas A; O'Sullivan, Aisling

    2015-03-01

    Atmospheric pollutants deposited on impermeable surfaces can be an important source of pollutants to stormwater runoff; however, modelling atmospheric pollutant loads in runoff has rarely been done, because of the challenges and uncertainties in monitoring their contribution. To overcome this, impermeable concrete boards (≈ 1m(2)) were deployed for 11 months in different locations within an urban area (industrial, residential and airside) throughout Christchurch, New Zealand, to capture spatially distributed atmospheric deposition loads in runoff over varying meteorological conditions. Runoff was analysed for total and dissolved Cu, Zn, Pb, and total suspended solids (TSS). Mixed-effect regression models were developed to simulate atmospheric pollutant loads in stormwater runoff. In addition, the models were used to explain the influence of different meteorological characteristics (e.g. antecedent dry days and rain depth) on pollutant build-up and wash-off dynamics. The models predicted approximately 53% to 69% of the variation in pollutant loads and were successful in predicting pollutant-load trends over time which can be useful for general stormwater planning processes. Results from the models illustrated the importance of antecedent dry days on pollutant build-up. Furthermore, results indicated that peak rainfall intensity and rain duration had a significant relationship with TSS and total Pb, whereas, rain depth had a significant relationship with total Cu and total Zn. This suggested that the pollutant speciation phase plays an important role in surface wash-off. Rain intensity and duration had a greater influence when the pollutants were predominantly in their particulate phase. Conversely, rain depth exerted a greater influence when a high fraction of the pollutants were predominantly in their dissolved phase. For all pollutants, the models were represented by a log-arctan relationship for pollutant build-up and a log-log relationship for pollutant wash

  7. Molecular magnetism of M6 hexagon ring in D(3d) symmetric [(MCl)6(XW9O33)2](12-) (M = Cu(II) and Mn(II), X = Sb(III) and As(III)).

    PubMed

    Yamase, Toshihiro; Ishikawa, Hirofumi; Abe, Hiroko; Fukaya, Keisuke; Nojiri, Hiroyuki; Takeuchi, Hideo

    2012-04-16

    Ferromagnetic [n-BuNH(3)](12)[(CuCl)(6)(SbW(9)O(33))(2)]·6H(2)O (1) and antiferromagnetic [n-BuNH(3)](12)[(MnCl)(6)(AsW(9)O(33))(2)]·6H(2)O (4) have been synthesized and structurally and magnetically characterized. Two complexes are structural analogues of [n-BuNH(3)](12)[(CuCl)(6)(AsW(9)O(33))(2)]·6H(2)O (2) and [n-BuNH(3)](12)[(MnCl)(6)(SbW(9)O(33))(2)]·6H(2)O (3) with their ferromagnetic interactions, first reported by us in 2006. (1) When variable temperature (T) direct current (dc) magnetic susceptibility (χ(M)) data are analyzed with the isotropic exchange Hamiltonian for the magnetic exchange interactions, χ(M)T vs T curves fitted by a full matrix diagonalization (for 1) and by the Kambe vector coupling method/Van Vleck's approximation (for 4) yield J = +29.5 and -0.09 cm(-1) and g = 2.3 and 1.9, respectively. These J values were significantly distinguished from +61.0 and +0.14 cm(-1) for 2 and 3, respectively. The magnetization under the pulsed field (up to 10(3) T/s) at 0.5 K exhibits hysteresis loops in the adiabatic process, and the differential magnetization (dM/dB) plots against the pulsed field display peaks characteristic of resonant quantum tunneling of magnetization (QTM) at Zeeman crossed fields, indicating single-molecule magnets for 1-3. High-frequency ESR (HFESR) spectroscopy on polycrystalline samples provides g(∥) = 2.30, g(⊥) = 2.19, and D = -0.147 cm(-1) for 1 (S = 3 ground state), g(∥) = 2.29, g(⊥) = 2.20, and D = -0.145 cm(-1) for 2 (S = 3), and g(∥) = 2.03 and D = -0.007 cm(-1) for 3 (S = 15). An attempt to rationalize the magnetostructural correlation among 1-4, the structurally and magnetically modified D(3d)-symmetric M (=Cu(II) and Mn(II))(6) hexagons sandwiched by two diamagnetic α-B-[XW(9)O(33)](9-) (X = Sb(III) and As(III)) ligands through M-(μ(3)-O)-W linkages, is made. The strongest ferromagnetic coupling for the Cu(6) hexagon of 2, the structure of which approximately provides the Cu(6)(μ(3)-O)(12

  8. Bioaccumulation of As, Cd, Cu, Fe and Pb in wild grasses affected by the Aznalcóllar mine spill (SW Spain).

    PubMed

    Madejón, P; Murillo, J M; Marañón, T; Cabrera, F; López, R

    2002-05-01

    The collapse of the tailing dam in the Aznalcóllar pyrite mine (SW Spain) occurred in April 1998 and affected approximately 4300 ha along the Agrio and Guadiamar valleys. An urgent soil cleaning up and remediation programme was started just after the accident. Eighteen months later, mineral nutrients and trace elements concentration in soil and two wild grasses--Cynodon dactylon and Sorghum halepense--have been studied. Three types of conditions are distinguished: (a) unaffected soils (control); (b) cleaned up and remediated soils (remediated); and (c) sludge-covered soils left in a fenced plot (non-remediated). As, Cd, Cu and Pb in grasses reached toxic levels for the food web in the non-remediated plot, while on remediated soils only Cd reached a toxic level in grass tissues. However, Pb and, to a lesser extent As and Fe, reached also toxic levels in unwashed plants (as they would be ingested by animals) in remediated soils. Both native grasses seem tolerant of trace elements pollution and suitable for stabilisation of spill-affected soils. PMID:12083702

  9. Accumulation of Trace Metal Elements (Cu, Zn, Cd, and Pb) in Surface Sediment via Decomposed Seagrass Leaves: A Mesocosm Experiment Using Zostera marina L.

    PubMed Central

    Konuma, Susumu; Nakamura, Yoshiyuki

    2016-01-01

    Accumulation of Cu, Zn, Cd, and Pb in the sediment of seagrass ecosystems was examined using mesocosm experiments containing Zostera marina (eelgrass) and reference pools. Lead was approximately 20-fold higher in the surface sediment in the eelgrass pool than in eelgrass leaves and epiphytes on the eelgrass leaves, whereas zinc and cadmium were significantly lower in the surface sediment than in the leaves, with intermediate concentrations in epiphytes. Copper concentrations were similar in both the surface sediment and leaves but significantly lower in epiphytes. Carbon and nitrogen contents increased significantly with increasing δ13C in surface sediments of both the eelgrass and reference pools. Copper, Zn, Cd, and Pb also increased significantly with increasing δ13C in the surface sediment in the eelgrass pool but not in the reference pool. By decomposition of eelgrass leaves with epiphytes, which was examined in the eelgrass pool, copper and lead concentrations increased more than 2-fold and approximately a 10-fold, whereas zinc and cadmium concentrations decreased. The high copper and lead concentrations in the surface sediment result from accumulation in decomposed, shed leaves, whereas zinc and cadmium remobilized from decomposed shed leaves but may remain at higher concentrations in the leaves than in the original sediments. The results of our mesocosm study demonstrate that whether the accumulation or remobilization of trace metals during the decomposition of seagrass leaves is trace metal dependent, and that the decomposed seagrass leaves can cause copper and lead accumulation in sediments in seagrass ecosystems. PMID:27336306

  10. Characterization of cadmium biosorption by Exiguobacterium sp. isolated from farmland soil near Cu-Pb-Zn mine.

    PubMed

    Park, Jin Hee; Chon, Hyo-Taek

    2016-06-01

    Bacteria have the ability to bind heavy metals on their cell wall. Biosorption is a passive and energy-independent mechanism to adsorb heavy metals. The efficiency of heavy metal biosorption can vary depending on several factors such as the growth phase of bacteria, solution pH, and existence of competitive heavy metals. In this study, Exiguobacterium sp. isolated from farmland soil near a mine site were used, and optimal conditions for Cd biosorption in solution were investigated. As bacterial growth progressed, Cd biosorption increased, which is attributed to changes in the structure and composition of the cell wall during bacterial growth. The biosorption process was rapid and was completed within 30 min. Cadmium biosorption was highest at pH 7 due to the dissociation of hydrogen ions and the increase of negative charges with increasing pH. In the mixed metal solution of Cd, Pb, and Zn, the amount of biosorption was in the order of Pb>Cd>Zn while in a single metal solution, the order was Cd≥Pb>Zn. The maximum adsorption capacity for Cd by the isolated bacteria was 15.6 mg/g biomass, which was calculated from the Langmuir isotherm model. Different adsorption efficiencies under various environmental conditions indicate that, to control metal mobility, the conditions for biosorption should be optimized before applying bacteria. The results showed that the isolated bacteria can be used to immobilize metals in metal-contaminated wastewater. PMID:26951224

  11. Structural, electric and magnetic properties of Bi(Pb)SrCa(Re)Cu(M)O vitroceramics

    NASA Astrophysics Data System (ADS)

    Simon, S.; Burzo, E.; Cozar, O.; Barbur, I.; Simon, V.; Ardelean, I.; Pop, V.; Borodi, Gh.

    1991-12-01

    The effect of the partial substitution of Ca ions by Gd and Eu ions and of Cu ions by elements from 3d group of transition metals on structural, electric and magnetic properties of Bi-vitroceramics from “2223” class was studied by X-ray diffraction, paramagnetic resonance, electric and statical magnetic susceptibility measurements.

  12. Determination of Cd, Cr, Cu, Pb and Zn in human semen by graphite furnace atomic absorption spectrometry after microwave sample dissolution.

    PubMed

    Alvarado, J; Moreno, R; Cristiano, A R

    1991-09-01

    Human semen samples were analyzed by graphite furnace atomic absorption spectrometry, using L'vov platforms and the method of standard additions, to determine their Cd, Cr, Cu, Pb and Zn content. The samples were analyzed directly and after conventional and microwave wet acid dissolution. Matrix modification, using magnesium and palladium nitrates and ammonium biphosphate solutions, was evaluated for the analysis of the microwave-digested samples. The best results were obtained for Cr, Cu and Zn using Pd(NO3)2, and a mixture of Mg(NO3)2 and Pd(NO3)2 solutions. The direct analysis of water-diluted semen produced inaccurate results with unacceptably high standard deviations. The results obtained for the microwave-dissolved samples showed relative standard deviation values within the range 0.63-8.4%. The analysis of spiked semen solutions showed recoveries of the added analytes ranging from 96 to 104%. The accuracy of the measurements was checked against the NIST 1,577a, bovine liver, standard reference material. Sample dissolution time was drastically reduced from 3-4 hours, using the conventional method, to approximately 8 minutes using the microwave-assisted wet acid digestion procedure. PMID:1821719

  13. Corrosion Behavior of Pb-Free Sn-1Ag-0.5Cu- XNi Solder Alloys in 3.5% NaCl Solution

    NASA Astrophysics Data System (ADS)

    Mohanty, Udit Surya; Lin, Kwang-Lung

    2013-04-01

    Potentiodynamic polarization techniques were employed in the present study to investigate the corrosion behavior of Pb-free Sn-1Ag-0.5Cu- XNi solder alloys in 3.5% NaCl solution. Polarization studies indicated that an increase in Ni content from 0.05 wt.% to 1 wt.% in the solder alloy shifted the corrosion potential ( E corr) towards more negative values and increased the linear polarization resistance. Increased addition of Ni to 1 wt.% resulted in significant increase in the concentration of both Sn and Ni oxides on the outer surface. Secondary-ion mass spectrometry and Auger depth profile analysis revealed that oxides of tin contributed primarily towards the formation of the passive film on the surface of the solder alloys containing 0.05 wt.% and 1 wt.% Ni. Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX) established the formation of a Sn whisker near the passive region of the solder alloy obtained from the polarization curves. The formation of Sn whiskers was due to the buildup of compressive stress generated by the increase in the volume of the oxides of Sn and Ni formed on the outer surface. The presence of Cl- was responsible for the breakdown of the passive film, and significant pitting corrosion in the form of distinct pits was noticed in Sn-1Ag-0.5Cu-0.5Ni solder alloy after the polarization experiment.

  14. Spin Liquid State in the 3D Frustrated Antiferromagnet PbCuTe_{2}O_{6}: NMR and Muon Spin Relaxation Studies.

    PubMed

    Khuntia, P; Bert, F; Mendels, P; Koteswararao, B; Mahajan, A V; Baenitz, M; Chou, F C; Baines, C; Amato, A; Furukawa, Y

    2016-03-11

    PbCuTe_{2}O_{6} is a rare example of a spin liquid candidate featuring a three-dimensional magnetic lattice. Strong geometric frustration arises from the dominant antiferromagnetic interaction that generates a hyperkagome network of Cu^{2+} ions although additional interactions enhance the magnetic lattice connectivity. Through a combination of magnetization measurements and local probe investigations by NMR and muon spin relaxation down to 20 mK, we provide robust evidence for the absence of magnetic freezing in the ground state. The local spin susceptibility probed by the NMR shift hardly deviates from the macroscopic one down to 1 K pointing to a homogeneous magnetic system with a low defect concentration. The saturation of the NMR shift and the sublinear power law temperature (T) evolution of the 1/T_{1} NMR relaxation rate at low T point to a nonsinglet ground state favoring a gapless fermionic description of the magnetic excitations. Below 1 K a pronounced slowing down of the spin dynamics is witnessed, which may signal a reconstruction of spinon Fermi surface. Nonetheless, the compound remains in a fluctuating spin liquid state down to the lowest temperature of the present investigation. PMID:27015508

  15. Spin liquid state in the 3D frustrated antiferromagnet PbCuTe2O6: NMR and muon spin relaxation studies

    DOE PAGESBeta

    Khuntia, P.; Bert, F.; Mendels, P.; Koteswararao, B.; Mahajan, A. V.; Baenitz, M.; Chou, F. C.; Baines, C.; Amato, A.; Furukawa, Y.

    2016-03-11

    In this study, PbCuTe2O6 is a rare example of a spin liquid candidate featuring a three-dimensional magnetic lattice. Strong geometric frustration arises from the dominant antiferromagnetic interaction that generates a hyperkagome network of Cu2+ ions although additional interactions enhance the magnetic lattice connectivity. Through a combination of magnetization measurements and local probe investigations by NMR and muon spin relaxation down to 20 mK, we provide robust evidence for the absence of magnetic freezing in the ground state. The local spin susceptibility probed by the NMR shift hardly deviates from the macroscopic one down to 1 K pointing to a homogeneousmore » magnetic system with a low defect concentration. The saturation of the NMR shift and the sublinear power law temperature (T) evolution of the 1/T1 NMR relaxation rate at low T point to a nonsinglet ground state favoring a gapless fermionic description of the magnetic excitations. Below 1 K a pronounced slowing down of the spin dynamics is witnessed, which may signal a reconstruction of spinon Fermi surface. Nonetheless, the compound remains in a fluctuating spin liquid state down to the lowest temperature of the present investigation.« less

  16. Concentration of Cu, Zn, Cr, Ni, Cd, and Pb in soil, sugarcane leaf and juice: residual effect of sewage sludge and organic compost application.

    PubMed

    Moretti, Sarah Mello Leite; Bertoncini, Edna Ivani; Vitti, André César; Alleoni, Luís Reynaldo Ferracciú; Abreu-Junior, Cassio Hamilton

    2016-03-01

    Many researchers have evaluated the effects of successive applications of sewage sludge (SS) on soil plant-systems, but most have not taken into account the residual effect of organic matter remaining from prior applications. Furthermore, few studies have been carried out to compare the effects of the agricultural use of SS and sewage sludge compost (SSC). Therefore, we evaluated the residual effect of SS and SSC on the heavy metal concentrations in soil and in sugarcane (Saccharum spp.) leaves and juice. The field experiment was established after the second harvesting of unburned sugarcane, when the organic materials were applied. The SS and SSC rates were (t ha(-1), dry base): 0, 12.5, 25, and 50; and 0, 21, 42, and 84, respectively. All element concentrations in the soil were below the standards established by São Paulo State environmental legislation. SS promoted small increases in Zn concentrations in soil and Cu concentrations in leaves. However, all heavy metals concentrations in the leaves were lower than the limits established for toxic elements and were in accordance with the limits established for micronutrients. There were reductions in the concentrations of Ni and Cu in soil and the concentration of Pb in juice, with increasing rates of SSC. The heavy metal concentrations were very low in the juice. Under humid tropical conditions and with short-term use, SS and SSC containing low heavy metal concentrations did not have negative effects on plants and soil. PMID:26879984

  17. Spin Liquid State in the 3D Frustrated Antiferromagnet PbCuTe2 O6 : NMR and Muon Spin Relaxation Studies

    NASA Astrophysics Data System (ADS)

    Khuntia, P.; Bert, F.; Mendels, P.; Koteswararao, B.; Mahajan, A. V.; Baenitz, M.; Chou, F. C.; Baines, C.; Amato, A.; Furukawa, Y.

    2016-03-01

    PbCuTe2O6 is a rare example of a spin liquid candidate featuring a three-dimensional magnetic lattice. Strong geometric frustration arises from the dominant antiferromagnetic interaction that generates a hyperkagome network of Cu2 + ions although additional interactions enhance the magnetic lattice connectivity. Through a combination of magnetization measurements and local probe investigations by NMR and muon spin relaxation down to 20 mK, we provide robust evidence for the absence of magnetic freezing in the ground state. The local spin susceptibility probed by the NMR shift hardly deviates from the macroscopic one down to 1 K pointing to a homogeneous magnetic system with a low defect concentration. The saturation of the NMR shift and the sublinear power law temperature (T ) evolution of the 1 /T1 NMR relaxation rate at low T point to a nonsinglet ground state favoring a gapless fermionic description of the magnetic excitations. Below 1 K a pronounced slowing down of the spin dynamics is witnessed, which may signal a reconstruction of spinon Fermi surface. Nonetheless, the compound remains in a fluctuating spin liquid state down to the lowest temperature of the present investigation.

  18. Ultrafine particle and fine trace metal (As, Cd, Cu, Pb and Zn) pollution episodes induced by industrial emissions in Huelva, SW Spain

    NASA Astrophysics Data System (ADS)

    Fernández-Camacho, R.; Rodríguez, S.; de la Rosa, J.; Sánchez de la Campa, A. M.; Alastuey, A.; Querol, X.; González-Castanedo, Y.; Garcia-Orellana, I.; Nava, S.

    2012-12-01

    Urban air quality impairment by ultrafine particles has become a matter of concern due to the adverse effects on human health. Most of the studies of ultrafine particles in urban air quality have focused on vehicle exhaust emissions. We studied how industrial emissions contribute to ultrafine particle concentrations in downwind urban ambient air. This research is based on experimental data collected in the ambient air of the industrial city of Huelva (SW Spain) over April 2008-December 2009 period (particle number, gaseous pollutants and black carbon concentrations and levels and chemical composition of PM10 and PM2.5 with daily and hourly resolution). This city is affected by emissions from the second largest Cu-smelter in Europe, phosphoric acid and fertilizer production plants and an oil refinery and petrochemical plant. Industrial emissions are the main cause of ultrafine particle episodes. When vehicle exhaust emissions are the main source, ultrafine particles typically show (24-h mean) concentrations within the range 14,700-5000 cm-3 (50th-1st), with 60% of these linked to this source and 30% to industrial emissions. In contrast, when daily mean levels of N are within the range 50,000-25,500 cm-3 (100th-70th), industrial and vehicle exhaust emissions accounted for 49 and 30%, respectively. High concentrations of toxic trace metals (As, Cu, Cd, Zn and Pb) were recorded when the study city suffered fumigations of the Cu-smelter plumes (e.g. 10-25 ng m-3 As, 1-2 ng m-3 Cd and >105 cm-3 of ultrafine particles). Because of these industrial emissions, ultrafine particle concentrations during daylight are about two times higher than those observed in other European cities. Recently, ultrafine particle emissions in vehicle exhausts have been subject to limit values in a recent stage of the EURO standards. Industrial emissions should also be considered.

  19. Assessing the effect of surface roughness on the wetting of Cu and Pd by Sn/Pb solder

    SciTech Connect

    O`Toole, E.J.; Yost, F.G.; Roberts, J.L.

    1996-12-31

    Artificially enhancing the solder ability of a surface can at times prove to be advantageous. As chip packaging geometries become increasingly complex, the issue of solder wettability becomes significantly more important. Here, the authors examine the effect of varying substrate surface roughness on solder wettability (area of spread) and the time required to reach terminal area of spread. Results are given for solder wetting experiments that were performed on copper (Cu) substrates having chemically etched surfaces, as well as, Alumina (Al{sub 2}O{sub 3}) substrates electroplated with various thicknesses of palladium (Pd). The effect of etching on the Al{sub 2}O{sub 3}/Pd specimens was also examined as related to surface roughness and solder spread. These surface treatments were found to significantly alter wettability. Substantial improvements were observed in both solder wettability and time to wet with the uniformly etched Cu surfaces used in this study. For the Cu substrates, the average terminal area of spread is shown to be directly related to the substrates root mean square (RMS) surface roughness. The rate of wetting of the Cu surfaces is also shown to increase when chemical surface treatment is used. Maximum wetting on the Al{sub 2}O{sub 3}/Pd specimens was found to be directly related to surface smoothness. The average terminal area of spread of Al{sub 2}O{sub 3}/Pd specimens is inversely related to the vertical distance from the highest surface peak to the deepest surface valley (i.e., peak-to-peak variation).

  20. Growth of InSb and InAs(1-x)Sb(x) by OM-CVD

    NASA Technical Reports Server (NTRS)

    Chiang, P. K.; Bedair, S. M.

    1984-01-01

    Organometallic chemical vapor deposition (OM-CVD) growth of InSb and InAs(1-x)Sb(x) has been obtained using triethylindium (TEI), trimethylantimony (TMS), and arsine (AsH3) on (100) GaAs, (100) InSb, and (111)-B InSb substrates. InSb with excellent morphology was achieved on both (100) InSb and (111)-B InSb substrates. The measured electron mobility at 300 K of undoped InSb grown on (100) GaAs semi-insulating substrates was 40,000 sq cm/V-s at a carrier concentration of ND-NA = 2.0 x 10 to the 16th per cu cm. Carrier concentration of ND-NA = 1.2 x 10 to the 15th per cu cm has been measured at 77 K. InAs(1-x)Sb(x) (x = 0.07-0.75) with mirror-like surfaces have been grown on (100) InSb and InAs substrates. This composition range of x between 0.55 and 0.75 (Eg = 0.1 eV) has been successfully achieved for the first time. Solid composition variations as a function of growth temperature and InSb substrate orientations are also discussed.

  1. Using grouper fish as bio-indicator of Cd, Cu, Pb and V in the vicinity of a single buoy mooring (SBM3) at Mina Al Fahal in the Sultanate of Oman.

    PubMed

    Abdul-Wahab, S A; Al-Husaini, I S; Rahmalan, A

    2013-12-01

    This paper investigated metal contamination in muscle tissue of the grouper (Epinephelus coioides) in the vicinity of a single buoy mooring (SBM3) at the Sultanate of Oman. The fish samples were analyzed for cadmium (Cd), copper (Cu), lead (Pb) and vanadium (V). The mean concentrations of Cd, Cu, Pb and V in the fish samples were 0.05 ± 0.004, 0.34 ± 0.013, 0.20 ± 0.018 and 0.03 ± 0.006 mg/kg, respectively. The results were compared with the corresponding permissible concentration limits according to the Sultanate of Oman (0.05, 3.28, 0.3 and 1.4 mg/kg for Cd, Cu, Pb and V, respectively) and the European Commission (0.05 mg/kg for Cd and 0.3 mg/kg for Pb). It was found that none of the overall mean metal concentrations exceeded the corresponding Omani legislation or European Commission limits. However, the overall mean concentration of Cd was identical to the maximum permissible limit of 0.05 mg/kg that has been established by both Commissions, and the limits were exceeded for mean Cd levels in fish at two of the six sampling stations at SBM3. In general, this study indicated that the fishes at SBM3 were not highly contaminated with these metals. PMID:24145924

  2. Effectively simultaneous naked-eye detection of Cu(II), Pb(II), Al(III) and Fe(III) using cyanidin extracted from red cabbage as chelating agent

    NASA Astrophysics Data System (ADS)

    Khaodee, Warangkhana; Aeungmaitrepirom, Wanlapa; Tuntulani, Thawatchai

    Simultaneous determination of Cu(II), Pb(II), Al(III) and Fe(III) using cyanidin as a chelating agent was investigated in terms of both quantitative and qualitative detections. Cyanidin was extracted and purified from red cabbage which is a local plant in Thailand. The selectivity of this method was examined by regulating the pH of cyanidin solution operated together with masking agents. It was found that Cu(II), Pb(II), Al(III) and Fe(III) simultaneously responded with the color change at pH 7, pH 6, pH 5 and pH 4, respectively. KF, DMG and the mixture of KF and DMG were used as masking agents for the determination of Fe(III), Al(III) and Pb(II), respectively. Results from naked-eye detection were evaluated by comparing with those of inductively coupled plasma (ICP), and there was no significant difference noticed. Cyanidin using as a multianalyte reagent could be employed for simultaneous determination of Cu(II), Pb(II), Al(III) and Fe(III) at the lowest concentration at 50, 80, 50 and 200 μM, respectively, by slightly varying pHs. Moreover, the proposed method could be potentially applied for real water samples with simplicity, rapidity, low cost and environmental safety.

  3. Pb solubility of the high-temperature superconducting phase Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+d}

    SciTech Connect

    Kaesche, S.; Majewski, P.; Aldinger, F.

    1994-12-31

    For the nominal composition of Bi{sub 2.27x}Pb{sub x}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+d} the lead content was varied from x=0.05 to 0.45. The compositions were examined between 830{degrees}C and 890{degrees}C which is supposed to be the temperature range over which the so-called 2223 phase (Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+d}) is stable. Only compositions between x=0.18 to 0.36 could be synthesized in a single phase state. For x>0.36 a lead containing phase with a stoichiometry of Pb{sub 4}(Sr,Ca){sub 5}CuO{sub d} is formed, for x<0.18 mainly Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+d} and cuprates are the equilibrium phases. The temperature range for the 2223 phase was found to be 830{degrees}C to 890{degrees}C but the 2223 phase has extremely varying cation ratios over this temperature range. Former single phase 2223 samples turn to multi phase samples when annealed at slightly higher or lower temperatures. A decrease in the Pb solubility with increasing temperature was found for the 2223 phase.

  4. Atmospheric metal pollution (Cr, Cu, Fe, Mn, Ni, Pb and Zn) in Oporto city derived from results for low-volume aerosol samplers and for the moss Sphagnum auriculatum bioindicator.

    PubMed

    Vasconcelos, M T; Tavares, H M

    1998-03-01

    A low-volume aerosol sampler with filters and bags of Sphagnum auriculatum were exposed, in parallel, to the atmosphere of Oporto city for approx. 2 months in 1994, during a dry weather period. The levels of Cr, Cu, Fe, Mn, Ni, Pb and Zn in the moss (weekly samples) and in the filters (daily samples) were determined by atomic absorption spectrophotometry and the results were compared. For all the heavy metals, the rate of metal uptake by moss was significantly correlated with the metal concentration in atmospheric aerosols. The results indicated that moss bags of S. auriculatum can provide a quantitative estimation of the concentration of different heavy metals in urban atmospheres, when specific calibration by mechanic monitoring, at the same sampling point, is performed during a first stage of biomonitoring. The mean aerosol metal concentrations found in the Oporto atmosphere were similar to those observed in other urban atmospheres in different countries. The relative order of the mean metal concentrations was Fe (1.8 micrograms/m3) > Zn > Pb > Cu > Cr > Mn > Ni (20 ng/m3). The aerosol Pb levels were monitored at different sampling points over various periods of time between 1991 and 1997. The mean Pb levels were < or = 0.5 microgram/m3 and approximately constant at each sample point up to January 1996. After that date it decreased by approx. 50%, in consequence of the reduction of the Pb concentration in leaded gasoline. PMID:9525044

  5. Synthesis of (Hg,Pb)(Sr,Ba) 2Ca 2Cu 3O z superconducting films via MOCVD and PLD

    NASA Astrophysics Data System (ADS)

    Klimonsky, S. O.; Samoilenkov, S. V.; Gorbenko, O. Yu.; Emelianov, D. A.; Lyashenko, A. V.; Lee, S. R.; Kaul, A. R.; Tretyakov, Yu. D.; Andrianov, D. G.; Kalinov, A. V.; Voloshin, I. F.

    2002-12-01

    (0 0 1)-oriented Sr-containing (Hg,Pb)-1223 films have been synthesised for the first time using the two-step procedure. Hg-free precursor films with the thickness up to 1 μm have been deposited by metalorganic chemical vapor deposition (MOCVD) or pulsed infra-red laser ablation (PLD) and then the films were annealed in a mercury-containing atmosphere in sealed quartz ampoules. No post-annealing in oxygen was used. The phase composition of the PLD-derived films depended crucially on the deposition temperature of the precursor films. MOCVD-derived films contained only very small amounts of non-superconducting phases according to XRD. The Tc=118 K and j c(77 K,0.01 T)=2.5×10 6A/cm 2 have been measured for the MOCVD-derived samples.

  6. Elaboration of Ti{sub 0.5}Pb{sub 0.5}Sr{sub 2}CaCu{sub 2}O{sub x} superconducting phases by an ultrasonic spray-pyrolysis process

    SciTech Connect

    Abraham, R.; Guenard, F.; Lebbou, K.; Trosset, S.; Cohen-Adad, M.T.; Jorda, J.L.; Couach, M.

    1998-02-01

    An ultrasonic spray-pyrolysis process has been used to prepare a homogeneous T{sub 10.5}Pb{sub 0.5}Sr{sub 2}CaCu{sub 2}O{sub x} high-temperature superconductor. Depending on experimental conditions, the grain morphology changes from platelet to cauliflower-like, contrary to the three copper layers series. The (Tl/Pb)-Sr-1212 phase has remarkable stability and does not decompose before melting. The critical temperature onset, about 80 K, is similar to that for samples prepared by the usual sintering methods.

  7. Detection of Cd, Pb, and Cu in non-pretreated natural waters and urine with thiol functionalized mesoporous silica and Nafion composite electrodes.

    PubMed

    Yantasee, Wassana; Charnhattakorn, Busarakum; Fryxell, Glen E; Lin, Yuehe; Timchalk, Charles; Addleman, R Shane

    2008-07-14

    Electrochemical sensors have great potential for environmental monitoring of toxic metal ions in waters due to their portability, field-deployability and excellent detection limits. However, electrochemical sensors employing mercury-free approaches typically suffer from binding competition for metal ions and fouling by organic substances and surfactants in natural waters, making sample pretreatments such as wet ashing necessary. In this work, we have developed mercury-free sensors by coating a composite of thiol self-assembled monolayers on mesoporous supports (SH-SAMMS) and Nafion on glassy-carbon electrodes. With the combined benefit of SH-SAMMS as an outstanding metal preconcentrator and Nafion as an antifouling binder, the sensors could detect 0.5 pp b of Pb and 2.5 pp b of Cd in river water, Hanford groundwater, and seawater with a minimal amount of preconcentration time (few minutes) and without any sample pretreatment. The sensor could also detect 2.5 pp b of Cd, Pb, and Cu simultaneously. The electrodes have long service times and excellent single and inter-electrode reproducibility (5% R.S.D. after 8 consecutive measurements). Unlike SAMMS-carbon paste electrodes, the SAMMS-Nafion electrodes were not fouled in samples containing albumin and successfully detected Cd in human urine. Other potentially confounding factors affecting metal detection at SAMMS-Nafion electrodes were studied, including pH effect, transport resistance of metal ions, and detection interference. With the ability to reliably detect low metal concentration ranges without sample pretreatment and fouling, SAMMS-Nafion composite sensors have the potential to become the next-generation metal analyzers for environmental and bio-monitoring of toxic metals. PMID:18558124

  8. Detection of Cd, Pb, and Cu in non-pretreated natural waters and urine with thiol functionalized mesoporous silica and Nafion composite electrodes

    SciTech Connect

    Yantasee, Wassana; Charnhattakorn, Budsarakum; Fryxell, Glen E.; Lin, Yuehe; Timchalk, Charles; Addleman, Raymond S.

    2008-05-21

    Electrochemical sensors have great potential for environmental monitoring of toxic metal ions in waters due to their portability, field-deployability and excellent detection limits. However, electrochemical sensors employing mercury-free approaches are normally suffered from metal binding competition and fouling by organic substances and surfactants in natural waters, thus tedious sample pretreatments such as wet ashing are needed. In this work, we have developed mercury-free sensors by coating a composite of thiol self-assembled monolayers on mesoporous supports (SH-SAMMS) and Nafion on glassy carbon electrodes. With a combined benefit of SH-SAMMS as outstanding metal preconcentrator and Nafion as antifouling binder, the sensors could detect 2.5 ppb of Cd and 0.5 ppb of Pb in river water, Hanford groundwater, and seawater after 3 and 6 minutes of preconcentration and without sample pretreatment. They could also detect 2.5 ppb of Cd, Pb, and Cu simultaneously after 5 minutes of preconcentration. The electrodes have long life time and excellent single and inter-electrode reproducibility (%RSD of 5 after 8 consecutive measurements). Unlike SAMMS-carbon paste electrodes, the SAMMS-Nafion electrodes were not fouled in samples containing albumin. Successful detection of Cd in human urine was also demonstrated. Other factors including pH effect, diffusion resistance, and Tl interference on the metal detection at SAMMS-Nafion electrodes were studied. With the ability to reliably detect low metal concentration ranges without sample pretreatment and fouling, the SAMMS-Nafion composite sensors have the potential to become the next generation metal analyzers for environmental and bio- monitoring of toxic metals.

  9. Detection of Cd, Pb, and Cu in Non-Pretreated Natural Waters and Urine with Thiol Functionalized Mesoporous Silica and Nafion Composite Electrodes

    PubMed Central

    Yantasee, Wassana; Charnhattakorn, Busarakum; Fryxell, Glen E.; Lin, Yuehe; Timchalk, Charles; Addleman, R. Shane

    2008-01-01

    Electrochemical sensors have great potential for environmental monitoring of toxic metal ions in waters due to their portability, field-deployability and excellent detection limits. However, electrochemical sensors employing mercury-free approaches typically suffer from binding competition for metal ions and fouling by organic substances and surfactants in natural waters, making sample pretreatments such as wet ashing necessary. In this work, we have developed mercury-free sensors by coating a composite of thiol self-assembled monolayers on mesoporous supports (SH-SAMMS™) and Nafion on glassy carbon electrodes. With the combined benefit of SH-SAMMS™ as an outstanding metal preconcentrator and Nafion as an antifouling binder, the sensors could detect 0.5 ppb of Pb and 2.5 ppb of Cd in river water, Hanford groundwater, and seawater with a minimal amount of preconcentration time (few minutes) and without any sample pretreatment. The sensor could also detect 2.5 ppb of Cd, Pb, and Cu simultaneously. The electrodes have long service times and excellent single and inter-electrode reproducibility (5% RSD after 8 consecutive measurements). Unlike SAMMS™-carbon paste electrodes, the SAMMS™-Nafion electrodes were not fouled in samples containing albumin and successfully detected Cd in human urine. Other potentially confounding factors affecting metal detection at SAMMS™-Nafion electrodes were studied, including pH effect, transport resistance of metal ions, and detection interference. With the ability to reliably detect low metal concentration ranges without sample pretreatment and fouling, SAMMS™-Nafion composite sensors have the