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Sample records for cd pb cu

  1. Pine bark as bio-adsorbent for Cd, Cu, Ni, Pb and Zn

    DEFF Research Database (Denmark)

    Cutillas-Barreiro, L.; Ansias-Manso, L.; Fernandez Calviño, David;

    2014-01-01

    % for Pb2+, 83-84% for Cu2+, 78-84% for Cd2+, 77-83% for Zn2+, and 70-75% for Ni2+, 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...

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

    Directory of Open Access Journals (Sweden)

    M. H. Al-Qunaibit

    2009-01-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  4. Electrodialytic removal of Cu, Zn, Pb, and Cd from harbor sediment: Influence of changing experimental conditions

    DEFF Research Database (Denmark)

    Nystrøm, Gunvor Marie; Ottosen, Lisbeth M.; Villumsen, Arne

    2005-01-01

    Electrodialytic remediation (EDR) was used to remove Cu, Zn, Pb, and Cd from contaminated harbor sediment. Extraction experiments were made prior to EDR, and the metal desorption was pH dependent but not liquid-to-solid ratio (L/S) dependent. The desorption order was Cd $GRT Zn $GRT Pb $GRT Cu...... for the removal of Cu, Zn, and Pb, probably due to oxidation of the sediments during stirring. Contrary, Cd removal was lower in the wet sediment as compared to the air-dried. The heavy metal removal was influenced by higher current strengths and varying L/S ratios. The highest removal obtained...... was in an experiment with dry sediment (L/S 8) and a 70 mA applied current that lasted 14 days. These experimental conditions were thereafter used to remediate more strongly contaminated sediments. Regardless of the initial heavy metal concentrations in the sediments, 67-87% Cu, 79-98% Cd, 90-97% Zn, and 91-96% Pb...

  5. Role of microbial inoculation and chitosan in phytoextraction of Cu, Zn, Pb and Cd by Elsholtzia splendens - a field case

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fayuan [Agricultural College, Henan University of Science and Technology, 70 Tianjin Road, Luoyang, Henan Province 471003 (China) and Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008 (China)]. E-mail: wfy1975@163.com; Lin Xiangui [Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008 (China); Yin Rui [Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008 (China)

    2007-05-15

    A field experiment was carried out to study the effect of microbial inoculation on heavy metal phytoextraction by Elsholtzia splendens and whether chitosan could have a synergistic effect with the microbial inocula. The microbial inocula consisted of a consortium of arbuscular mycorrhizal fungi and two Penicillium fungi. Three treatments were included: the control, inoculation with microbial inocula, and the inoculation combined with chitosan. Microbial inoculation increased plant biomass especially shoot dry weight, enhanced shoot Cu, Zn and Pb concentrations but did not affect Cd, leading to higher shoot Cu, Zn, Pb and Cd uptake. Compared with microbial inoculation alone, chitosan application did not affect plant growth but increased shoot Zn, Pb and Cd concentrations except Cu, which led to higher phytoextraction efficiencies and partitioning to shoots of Zn, Pb and Cd. These results indicated synergistic effects between microbial inocula and chitosan on Zn, Pb and Cd phytoextraction. - Co-application of microbial inocula and chitosan enhanced heavy metal phytoextraction by E. splendens.

  6. Fractionation of Cd, Cu, Ni, Pb, and Zn in floodplain soils from Egypt, Germany and Greece

    Directory of Open Access Journals (Sweden)

    Shaheen S. M.

    2013-04-01

    Full Text Available Trace elements are potentially toxic to human life and the environment. Element toxicity depends on chemical associations in soils. Therefore, determining the chemical form of an element in soils is important to evaluate its mobility and bioavailability. Initial soil development in river floodplains influences soil properties, processes and therefore behavior of trace elements. In this study, three different floodplain soils sampled at three rivers (Nile/Egypt, Elbe/Germany and Penios/Greece were used to link soil development and properties to the geochemical fractions and mobility of some trace elements. Sequential extraction was used to fractionate five trace elements (Cd, Cu, Ni, Pb and Zn into five operationally defined groups: water soluble + exchangeable, carbonate, Fe-Mn oxide, organic, and residual. German soil showed the highest total concentration of the studied elements (except Ni. The Greek soil had the greatest amount of Ni. The residual fraction was the abundant pool for the studied elements examined in the Egyptian and Greek soils while the non-residual fraction was the dominant pool for all elements in the German soil. A significant amount (71- 94% of all elements was present in German soil in the potentially available fraction: non-residual fraction, while the amount of this fraction ranged between 9 and 39 % in Greek soil and between 9 and 34 % in Egyptian soil. These suggest that the potential availability of the studied trace elements was extremely high in German soil compared to the Egyptian and Greek soil. In the German soil, most of the non-residual Cd, Ni and Zn were bounded with the Fe-Mn oxide fraction, while Cu and Pb distributed in the organic fraction. While in the Egyptian and Greek soils Fe-Mn oxide fraction was the abundant pool for the studied elements except for Cd, in which the exchangeable and the carbonate fractions had the greatest amount of Cd. Assuming that mobility and bioavailability of these elements

  7. EDTA and citric acid mediated phytoextraction of Zn, Cu, Pb and Cd through marigold (Tagetes erecta).

    Science.gov (United States)

    Sinhal, V K; Srivastava, Alok; Singh, V P

    2010-05-01

    Phytoextraction is an emerging cost-effective solution for remediation of contaminated soils which involves the removal of toxins, especially heavy metals and metalloids, by the roots of the plants with subsequent transport to aerial plant organs. The aim of the present investigation is to study the effects of EDTA and citric acid on accumulation potential of marigold (Tagetes erecta) to Zn, Cu, Pb, and Cd and also to evaluate the impacts of these chelators (EDTA and citric acid) in combination with all the four heavy metals on the growth of marigold. The plants were grown in pots and treated with Zn (7.3 mg l(-1)), Cu (7.5 mg I(-1)), Pb (3.7 mg l(-1)) and Cd (0.2 mg l(-1)) alone and in combination with different doses of EDTA i.e., 10, 20 and 30 mg l(-1). All the three doses of EDTA i.e., 10, 20 and 30 mg l(-1) significantly increased the accumulation of Zn, Cu, Pb and Cd by roots, stems and leaves as compared to control treatments. The 30 mg l(-1) concentration of citric acid showed reduced accumulation of these metals by root, stem and leaves as compared to lower doses i.e., 10 and 20 mg l(-1). Among the four heavy metals, Zn accumulated in the great amount (526.34 mg kg(-1) DW) followed by Cu (443.14 mg kg(-1) DW), Pb (393.16 mg kg(-1) DW) and Cd (333.62 mg kg(-1) DW) in leaves with 30 mg l(-1) EDTA treatment. The highest concentration of EDTA and citric acid (30 mg l(-1)) caused significant reduction in growth of marigold in terms of plant height, fresh weight of plant, total chlorophyll, carbohydrate content and protein content. Thus EDTA and citric acid efficiently increased the phytoextractability of marigold which can be used to remediate the soil contaminated with these metals.

  8. Investigation of Pb, Cd, Cu and Mg Concentrations in Groundwater Resources of Razan Plain

    OpenAIRE

    S. Sobhan Ardakani; M. Maanijou; Asadi, H.

    2015-01-01

    Introduction & Objective: Iran is located in the dry and semi dry regions, thus almost 90% of the required fresh water is exploited from groundwater resources. Due to the increasing pol-lution of water resources, the purpose of this study was evaluation of Pb, Cd, Cu and Mg concentrations in groundwater resources of Razan Plain and preparing the zoning map using GIS. Materials & Methods: Groundwater samples were collected from 20 selected stations during two seasons in 2012. The samples were ...

  9. [Removal of metal ions Cu2+, Cd+ and Pb+ from solutions by sorption on slag].

    Science.gov (United States)

    Chen, Xiao; Hou, Wen-hua; Wang, Qun-hui

    2009-10-15

    Batch experiments were carried out to investigate the adsorption kinetics and thermodynamic characteristics of heavy metal ions Cu2+, Cd2+ and Pb2+ on the electric are furnace (EAF) slag from Baoshan Steel Factory. Several kinds of techniques including XRD analysis, BET specific surface analysis and SEM/EDS analysis were employed to determine the physico-chemical and surface characteristics of slag. Results indicated that the adsorption rate of heavy metal ions on the EAF slag was relatively high, and the sorption rate followed the order Cd2+ > Pb2+ > Cu2+. The adsorption kinetics obeyed first-order kinetics model (R2 > 0.99). Adsorption isotherm experiment showed that adsorption isotherm of heavy metal ions on slag fitted Langmuir model, and the maximum adsorption capacity of Cu2+, Cd2+ and Pb2+ was 0.101, 0.058 and 0.120 mmol x g(-1), respectively. The adsorption of heavy metal ions on slag was a spontaneous reaction (deltaG0 0). The effect of enthopy was the main driving force of the spontaneous adsorption reaction. The analysis results of SEM/EDS revealed the changes of surface morphology and chemical proportion before and after adsorption. Due to low-cost and high-efficiency, electric are furnace slag showed great potential for the treatment of heavy metal polluted wastewaters.

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

    Science.gov (United States)

    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.

  11. Test of experimental set-ups for electrodialytic removal of Cu, Zn, Pb and Cd from different contaminated harbour sediments

    DEFF Research Database (Denmark)

    Nystrøm, Gunvor Marie; Ottosen, Lisbeth M.; Villumsen, Arne

    2005-01-01

    of the sediment slurry, the other without stirring. The removal of heavy metals was highest in the non-calcareous sediment, where 94% Cd, 91% Zn and 73% Cu were removed after 24 days. The highest removal obtained for the calcareous sediment was 81% Cd, 76% Zn, 75% Pb and 53% Cu after 21 days, with stirred...... was the most stable in these experiments, and thus, the stirred set-up is the best choice for experimental set-up. The order in which the heavy metals were removed from the harbour sediments was Cd>Zn>Pb>Cu....

  12. RELATIONSHIPS BETWEEN FRACTIONATIONS OF Pb, Cd, Cu, Zn AND Ni AND SOIL PROPERTIES IN URBAN SOILS OF CHANGCHUN, CHINA

    Institute of Scientific and Technical Information of China (English)

    GUO Ping; XIE Zhong-lei; LI Jun; KANG Chun-li; LIU Jian-hua

    2005-01-01

    An extensive soil investigation was conducted in different domains of Changchun to disclose the fractionations of Pb, Cu, Cd, Zn and Ni in urban soils. Meanwhile correlation analysis and multiple stepwise regressions were used to define relationships between soil properties and metal fractions and the chief factors influencingthe fractionation of heavy metals in the soils. The results showed that Pb, Ni and Cu were mainly associated with the residual and organic forms; most of Cd was concentrated in the residual and exchangeable fractions. Zn in residual and carbonate fraction was the highest. The activities of the heavy metals probably declined in the following order: Cd, Zn,Pb, CuandNi. The chemical fractions of heavy metals in different domains in Changchun City were of significantly spatial heterogeneity. Soil properties had different influences on the chemical fractions of heavy metals to some extent and the main factors influencing Cd, Zn, Pb, Cu and Ni fractionation and transformation were apparently different.

  13. Dissolved Cu, Pb, Zn and Cd in the South China Sea surface waters

    Institute of Scientific and Technical Information of China (English)

    Huo Wenmian; Ji Weidong; Xu Kuncan

    2001-01-01

    A total of 106 surface water samples were collected in the South China Sea during two transects in June and December 1998. The samples were collected with strictly contamination free procedure and trace metals were measured by clean laboratory methods and GFAAS. The mean concentrations for the dissolved fractions are: Cu 0.100 μg/dm3, Pb 0.060 μg/dm3, Zn 0.086 μg/dm3, Cd 0.007 μg/dm3, which is close to the world open ocean's level. The spatial distribution of the trace heavy metals shows higher concentrations in offshore area and lower concentrations in the central in the South China Sea, and the concentrations decrease with the distance from the offshore, which suggests the existence of significant continental shelf input of the trace heavy metals. The correlationship among the elements is better in summer than that in winter. Cu is positively correlated with Cd in both seasons and it is also found for the first time that they are positively correlated with nutrients in the South China Sea surface waters which further indicate the biogeochemical cycle of these elements in the marine environment. The baseline value of Cu, Pb, Zn, Cd in the South China Sea surface waters is obtained through statistical analysis.

  14. Effects of Pb2+, Cd2+ and Cu2+ on the Aqueous Zn2+ Sorption by Hydroxyapatite

    Institute of Scientific and Technical Information of China (English)

    QI Yong; LIU Yu

    2006-01-01

    In this paper, the behaviors of aqueous zinc sorption by hydroxyapatite in the co-existence of Pb2+, Cd2+ and Cu2+ are investigated, the effects of Pb2+, Cd2+ and Cu2+ on the sorption of Zn2+ are discussed, and the hydroxyapatite sorption capabilities for Pb2+, Cd2+, Cu2+ and Zn2+ are compared.The experimental results show that the Zn2+ removal efficiency decreases gradually with the increase of the Cd2+ concentration of the solution, and there is no sorption preference between Cd2+ and Zn2+. On the other hand, the Zn2+ removal efficiency rapidly decreases rapidly with the increase of the Cu2+ concentration of the solution, and there is a clear sorption preference between Cu2+ and Zn2+. It is noticed that the Zn2+ removal efficiency is hardly changed with the variance of Pb2+ concentration because the removal mechanisms for these two ions are totally different. It is concluded that the adsorption affinities of the heavy metals for the hydroxyapatite follows this sequence: Pb2+> Cu2+>Cd2+> Zn2+.

  15. Physiological responses and detoxific mechanisms to Pb, Zn, Cu and Cd in young seedlings of Paulownia fortunei.

    Science.gov (United States)

    Wang, Jiang; Li, Weihua; Zhang, Chongbang; Ke, Shisheng

    2010-01-01

    Paulownia fortunei has been successfully used in the phytoremediation of many Pb/Zn mine tailings. However, seed germination and young seedlings of P. fortunei rarely occurred in these mine tailings. The physiological responses and detoxific mechanisms of P. fortunei young seedling to Pb, Zn, Cu and Cd stress were investigated. The germinated rate, shoot length, chlorophyll and carotenoid contents in leaves of young seedlings had a great reduction under Zn and Cu treatments, but had little decrease under Pb and Cd treatments. The production rate of O2*-, H2O2 and malondialdehyde (MDA) contents significantly increased in response to added Zn and Cu indicating great oxidative stress for young seedlings, but they had no significant change to added Pb and Cd. Young seedlings had effective detoxific mechanism to Pb and Cd, as antioxidant enzymes activities, phytochelatins (PCs-SH) and proline contents increased with increasing rates of added Pb and Cd. However, young seedlings had un-effective detoxific mechanisms to Zn and Cu stress. Results revealed the heavy metals (such as Cu) that present at low concentrations in mine tailings may be major constraint for the survival of young seedlings.

  16. Spatial distribution of dissolved Pb,Hg,Cd,Cu and As in the Bohai Sea

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Characteristics of the spatial distribution of selected dissolved heavy metals were analyzed during large scale surveys from August 12 to 25.2003 in the Bohai Sea.Dissolved Pb was the only element with average concentrations higher than the grade-one sea water quality standard of China.The spatial distribution of dissolved Pb in surface water was similar to those of Cd,Cu and As,where the isopleths generally indicated decreasing values from the bays to the central areas.Only for Hg did the high concentrations not only appear in Liaodong Bay,Bohai Bay and Laizhou Bay,but also in the Central Area,viz.not only in inshore but also in offshore areas.Vertical distributions of dissolved Pb,Cd,Cu and As were largely uniform,while that of dissolved Hg increased with depth.We infer that the input of pollutants from land was the main influencing factor for the detected distribution patterns of dissolved heavy metals,followed by the dynamics of sea water,release from bottom sediments and biochemical processes.Comparing with historical data,average concentrations of dissolved heavy metals appear to decline in recent years.

  17. ELECTROOXIDATION OF METHANOL ON PT MODIFIED WITH ADATOMS (NI, CU, PB, CD

    Directory of Open Access Journals (Sweden)

    A.Khouchaf

    2015-05-01

    Full Text Available The electro oxidation of methanol has been studied in alkaline medium NaOH 0.1 M and acid medium H2SO4 0.5 M on a platinum electrode and a platinum modified by adatom adsorption (Ni, Cu, Pb, and Cd. The influence of different experimental variables (methanol concentration, and temperature is reported. Preliminary investigations by cyclic voltammetry showed that the catalytic activity of platinum is still too low to be considered as a practical catalyst. Underpotential deposition of lead, nickel, cadmium, or copper adatoms at platinum allowed increasing significantly the current densities.

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

    Science.gov (United States)

    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 PbCdCdCd, 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.

  19. The CdS/CdSe/ZnS Photoanode Cosensitized Solar Cells Basedon Pt, CuS, Cu2S, and PbS Counter Electrodes

    Directory of Open Access Journals (Sweden)

    Tung Ha Thanh

    2014-01-01

    Full Text Available Highly ordered mesoporous TiO2 modified by CdS, CdSe, and ZnS quantum dots (QDs was fabricated by successive ionic layer adsorption and reaction (SILAR method. The quantity of material deposition seems to be affected not only by the employed deposition method but also and mainly by the nature of the underlying layer. The CdS, CdSe, and ZnS QDs modification expands the photoresponse range of mesoporous TiO2 from ultraviolet region to visible range, as confirmed by UV-Vis spectrum. Optimized anode electrodes led to solar cells producing high current densities. Pt, CuS, PbS, and Cu2S have been used as electrocatalysts on counter electrodes. The maximum solar conversion efficiency reached in this work was 1.52% and was obtained by using Pt electrocatalyst. CuS, PbS, and Cu2S gave high currents and this was in line with the low charge transfer resistances recorded in their case.

  20. Bioelectrochemical recovery of Cu, Pb, Cd, and Zn from dilute solutions.

    Science.gov (United States)

    Modin, Oskar; Wang, Xiaofei; Wu, Xue; Rauch, Sebastien; Fedje, Karin Karlfeldt

    2012-10-15

    In a microbial bioelectrochemical system (BES) living microorganisms catalyze the anodic oxidation of organic matter at a low anode potential. We used a BES with a biological anode to power the cathodic recovery of Cu, Pb, Cd, and Zn from a simulated municipal solid waste incineration ash leachate. By varying the control of the BES, the four metals could sequentially be recovered from a mixed solution by reduction on a titanium cathode. First, the cell voltage was controlled at zero, which allowed recovery of Cu from the solution without an electrical energy input. Second, the cathode potential was controlled at -0.51 V to recover Pb, which required an applied voltage of about 0.34 V. Third, the cathode potential was controlled at -0.66 V to recover Cd, which required an applied voltage of 0.51 V. Finally, Zn was the only metal remaining in solution and was recovered by controlling the anode at +0.2V to maximize the generated current. The study is the first to demonstrate that a BES can be used for cathodic recovery of metals from a mixed solution, which potentially could be used not only for ash leachates but also for e.g. metallurgical wastewaters and landfill leachates.

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

    Science.gov (United States)

    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

  2. Nerita chameleon as Biomonitoring Agent for Pb, Cd, Cu and Zn in Malaysian Intertidal Rocky Shore Environment

    Directory of Open Access Journals (Sweden)

    Mohd Fuad Miskon

    2015-06-01

    Full Text Available Pb, Cd, Cu and Zn in the soft tissue of Nerita chameleon from particular rocky shore sites along the east coast of Peninsular Malaysia were investigated. Samples were measured using ICP-MS with standard configuration. The metal accumulation patterns indicate consistent enrichment of essential metals. Locations with relatively high concentrations of the contaminant metals Pb, Cd and Cu are related to their close proximity to industrial activities and urban sites. Comparison with maximum permissible limits of toxic metals in food indicated the values were well within safety levels.

  3. Continuous biosorption of Pb/Cu and Pb/Cd in fixed-bed column using algae Gelidium and granulated agar extraction algal waste

    Energy Technology Data Exchange (ETDEWEB)

    Vilar, Vitor J.P. [LSRE-Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)], E-mail: vilar@fe.up.pt; Loureiro, Jose M. [LSRE-Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)], E-mail: loureiro@fe.up.pt; Botelho, Cidalia M.S. [LSRE-Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)], E-mail: cbotelho@fe.up.pt; Boaventura, Rui A.R. [LSRE-Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)], E-mail: bventura@fe.up.pt

    2008-06-15

    Continuous metal ions biosorption from Pb/Cu and Pb/Cd solutions onto seaweed Gelidium sesquipedale and a composite material prepared from an industrial algal waste was performed in a packed bed column. A binary Langmuir equation describes well the equilibrium data and indicates a good adsorption capacity. In the sorption process, Cd and Cu break through the column faster than Pb due to its lower affinity for the biosorbent. An overshoot in the outlet Cd concentration was observed and explained by competitive adsorption between Pb and Cd, whereby the higher Pb affinity for the biosorbent displaces bound Cd ions. A small overshoot happens for Cu adsorption in the presence of Pb ions. Desorption using 0.1 M HNO{sub 3} as eluant, was 100% effective. A mass transfer model for the adsorption and desorption processes, considering an external and intraparticle film resistance, adequately simulates the column performance. A binary Langmuir equation was used to describe equilibrium for the saturation process and a mass action law for the desorption process. Elution process is defined as an ion exchange mechanism, between protons and metal ions.

  4. Continuous biosorption of Pb/Cu and Pb/Cd in fixed-bed column using algae Gelidium and granulated agar extraction algal waste.

    Science.gov (United States)

    Vilar, Vítor J P; Loureiro, José M; Botelho, Cidália M S; Boaventura, Rui A R

    2008-06-15

    Continuous metal ions biosorption from Pb/Cu and Pb/Cd solutions onto seaweed Gelidium sesquipedale and a composite material prepared from an industrial algal waste was performed in a packed bed column. A binary Langmuir equation describes well the equilibrium data and indicates a good adsorption capacity. In the sorption process, Cd and Cu break through the column faster than Pb due to its lower affinity for the biosorbent. An overshoot in the outlet Cd concentration was observed and explained by competitive adsorption between Pb and Cd, whereby the higher Pb affinity for the biosorbent displaces bound Cd ions. A small overshoot happens for Cu adsorption in the presence of Pb ions. Desorption using 0.1 M HNO3 as eluant, was 100% effective. A mass transfer model for the adsorption and desorption processes, considering an external and intraparticle film resistance, adequately simulates the column performance. A binary Langmuir equation was used to describe equilibrium for the saturation process and a mass action law for the desorption process. Elution process is defined as an ion exchange mechanism, between protons and metal ions.

  5. Competitive adsorption of Cd, Cu, Hg and Pb by agricultural soils of the Changjiang and Zhujiang deltas in China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Soils can often be contaminated simultaneously by more than one heavy metal. The sorption-desorption behavior of a metal in a soil will be affected by the presence of other metals. Therefore, selective retention and competitive adsorption of the soils to heavy metals can affect their availability and movement through the soils. In this study, the simultaneous competitive adsorption of four heavy metals (Cd, Cu, Hg, and Pb) on ten agricultural soils collected from the Changjiang and Zhujiang deltas,China was assessed. The results showed that the competition affected the behavior of heavy metal cations in such a way that the soils adsorbed less Cd and Hg, and more Pb and Cu with increasing total metal concentrations, regardless of the molar concentration applied. As the applied concentrations increased, Pb and Cu adsorption increased, while Cd and Hg adsorption decreased.The adsorption sequence most found was Pb>Cu>Hg>Cd. The maximum adsorption capacity for the heavy metal cations was calculated, and affected markedly by soil properties. The results suggest that Hg and Cd have higher mobility associated to the lower adsorption and that Pb and Cu present the opposite behavior. Significant correlations were found between the maximum adsorption capacity of the metals and pH value and exchangeable acid, suggesting that soil pH and exchangeable acid were key factors controlling the solubility and mobility of the metals in the agricultural soils.

  6. Bioaccumulation of Pb, Cd, Cu, and Cr by Porphyridium cruentum (S.F. Gray Nägeli

    Directory of Open Access Journals (Sweden)

    Tri Retnaningsih Soeprobowati

    2013-06-01

    Full Text Available The red microalgae Porphyridium cruentum (S.F. Gray Nägeli usually was used as feeds, a pigment for food and cosmetic, and antiviral activity that might be became industrial interest. Similar to another microalgae, P. cruentum has an ability to remediate heavy metals pollution, however research on it still limited. This research was conducted in order to find out the the accumulation of Pb, Cd, Cr, and Cu on the P. cruentum. A laboratory experiment were developed with different concentrations. Based on this research, P. cruentum with the treatment of 1 mg/L had reduced higher Cu, Pb, Cd, and Cr concentrations rather than 3 and 5 mg/L concentrations, respectively. This was also similar to the BCF, that in day 8 in order of Cu > Cr > Cd > Pb, respectively; however, in day 15 was Cu > Pb > Cd > Cr. The length of treatment influenced BCF value. P. cruentum was good for bioremediation of heavy metal pollution, with the advantage of the short of accumulation time.

  7. Risk assessment for Cd, Cu, Pb, and Zn in urban soils: chemical availability as the central concept

    NARCIS (Netherlands)

    Rodrigues, S.R.; Cruz, N.; Coelho, C.; Henriques, B.; Carvalho, L.; Duarte, A.C.; Pereira, E.; Römkens, P.F.A.M.

    2013-01-01

    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 HNO(3) (reactive), 0.01 M CaCl(2) (available), and 0.4 M glycine at pH = 1.5, SBET method (oral bioac

  8. Utilização de pelos de animais silvestres para monitoramento ambiental de Cd, Cr, Cu, Fe, Mn, Pb e Zn Utilization of wild animal hair for the environmental monitoring of Cd, Cr, Cu, Fe, Mn, Pb e Zn

    Directory of Open Access Journals (Sweden)

    Carlos Henrique Hoff Brait

    2009-01-01

    Full Text Available This study investigates the use of wild animal hair of C. brachyurus, C. thous and L. pardalis as biomonitors of trace metal at Parque Nacional das Emas, Brazil. Results reveal a strong correlation between Cd and Pb as well as Cu and Zn, which suggests a single source of emission. Most metals showed a lower or equal concentration than those obtained in previous studies. The research shows that monitoring may be performed only with Zn, Pb, Cd, and Cr because of statistical similarity and of a non-natural occurrence of large amounts of the material under analysis.

  9. Effect of Cu(II), Cd(II) and Zn(II) on Pb(II) biosorption by algae Gelidium-derived materials.

    Science.gov (United States)

    Vilar, Vítor J P; Botelho, Cidália M S; Boaventura, Rui A R

    2008-06-15

    Biosorption of Pb(II), Cu(II), Cd(II) and Zn(II) from binary metal solutions onto the algae Gelidium sesquipedale, an algal industrial waste and a waste-based composite material was investigated at pH 5.3, in a batch system. Binary Pb(II)/Cu(II), Pb(II)/Cd(II) and Pb(II)/Zn(II) solutions have been tested. For the same equilibrium concentrations of both metal ions (1 mmol l(-1)), approximately 66, 85 and 86% of the total uptake capacity of the biosorbents is taken by lead ions in the systems Pb(II)/Cu(II), Pb(II)/Cd(II) and Pb(II)/Zn(II), respectively. Two-metal results were fitted to a discrete and a continuous model, showing the inhibition of the primary metal biosorption by the co-cation. The model parameters suggest that Cd(II) and Zn(II) have the same decreasing effect on the Pb(II) uptake capacity. The uptake of Pb(II) was highly sensitive to the presence of Cu(II). From the discrete model it was possible to obtain the Langmuir affinity constant for Pb(II) biosorption. The presence of the co-cations decreases the apparent affinity of Pb(II). The experimental results were successfully fitted by the continuous model, at different pH values, for each biosorbent. The following sequence for the equilibrium affinity constants was found: Pb>Cu>Cd approximately Zn.

  10. Graphite furnace analysis of a series of metals (Cu, Mn, Pb, Zn and Cd) in ox kidney

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Vivianne L.B. de; Nascimento, Rizia K. do; Paiva, Ana Claudia de; Silva, Josenilda M. da, E-mail: vlsouza@cnen.gov.br, E-mail: riziakelia@hotmail.com, E-mail: acpaiva@cnen.gov.br, E-mail: jmnilda@hotmail.com [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Melo, Jessica V. de, E-mail: Jessica_clorofila@hotmail.com [Universidade de Pernambuco, Recife, PE (Brazil)

    2013-07-01

    The aim of this study was to create a methodology for animal tissue analysis, with the use of flame atomic absorption spectrophotometry techniques and graphite furnace analysis to determining metal concentrations in ox kidney. The organ of this animal can be considered a great nutritional food, due to the high protein and micronutrient content beyond the ability to absorb and concentrate important metals such as Zn, Fe, Mn and Se. On the other hand, there is a risk when eating this food owing to the capacity to accumulate toxic metals such as Pb and Cd. In accordance with the laboratory analysis, Zn can be analyzed by flame atomic absorption spectrophotometry, but other metals such as Cu, Mn, Pb and Cd, could only be detected by graphite furnace analysis. The results showed that there is more Zn and Cu than other metals. Such metals follows an order reported by the literature (Zn > Cu > Cd > Pb > Mn). The results showed that kidney is actually a rich source of Zn and Cu. The Cd levels in the ox kidney did not exceed the values which cause toxic effects. The adequacy of the results indicates that the proposed methodology can be used for animal tissue analysis.(author)

  11. UJI TOLERANSI TANAMAN TEMBAKAU (Nicotiana tabacum L. TERHADAP CEKAMAN KADMIUM (Cd, TIMBAL (Pb, DAN TEMBAGA (Cu PADA KULTUR CAIR

    Directory of Open Access Journals (Sweden)

    S Rosidah

    2014-11-01

    Full Text Available Penelitian ini menyelidiki respon fisiologis, anatomis, dan morfologis tanaman tembakau (Nicotiana tabacum L. terhadap cekaman logam berat Cu, Cd, dan Pb. Sampel yang digunakan adalah tembakau umur 3-4 minggu yang dikecambahkan secara in vitro dan kemudian dipapar logam berat selama 14 hari. Desain penelitian yang digunakan yaitu rancangan acak lengkap dengan satu faktor, yaitu konsentrasi logam Cu (0 µM, 50 µM, 100 µM, 150 µM & 200 µM, Cd (0 µM, 50 µM, 100 µM, 200 µM & 300 µM, dan Pb (0 µM, 5 µM, 20 µM, 50 µM & 100 µM. Parameter yang digunakan: pertambahan panjang akar, pertambahan jumlah akar, akumulasi logam dalam akar, lokalisasi penimbunan dalam akar, dan warna daun. Bertambahnya konsentrasi logam menghambat pertumbuhan akar dan menyebabkan deposit logam pada jaringan akar dan gejala klorosis. Hasil uji Atomic Absorbtion Spectrophotometry (AAS menunjukkan semakin besar konsentrasi semakin banyak akumulasi logam pada jaringan akar. Akan tetapi, akumulasi Cd pada konsentrasi 200 µM lebih besar dibanding pada konsentrasi 300 µM. Analisis kualitatif membuktikan bahwa cekaman Cu tidak berpengaruh signifikan terhadap warna daun, sedangkan pada cekaman Cd (100, 150 dan 200 µM dan Pb (150 µM daun mengalami klorosis. Pada konsentrasi logam yang rendah seperti 50 µM Cu, 50 µM Cd, dan 5 µM Pb tidak berbeda nyata dengan kontrol. Dengan demikian disimpulkan bahwa tembakau mampu mentoleransi cekaman logam pada konsentrasi yang rendah.  This research investigated the physiological, anatomical, and morphological responses of tobacco (Nicotiana tabacum L. on stresses of heavy metals Cu, Cd, and Pb. The samples were 3- to 4-week tobacco plants germinated in vitro and then were exposed to heavy metals for 14 days. This study used a completed random design with single factor, i.e. the concentrations of Cu (0 µM, 50 µM, 100 µM, 150 µM & 200 µM, Cd (0 µM, 50 µM, 100 µM, 200 µM & 300 µM, and Pb (0 µM, 5 µM, 20 µM, 50 µM & 100

  12. Investigation of Pb, Cd, Cu and Mg Concentrations in Groundwater Resources of Razan Plain

    Directory of Open Access Journals (Sweden)

    S. Sobhan Ardakani

    2015-01-01

    Full Text Available Introduction & Objective: Iran is located in the dry and semi dry regions, thus almost 90% of the required fresh water is exploited from groundwater resources. Due to the increasing pol-lution of water resources, the purpose of this study was evaluation of Pb, Cd, Cu and Mg concentrations in groundwater resources of Razan Plain and preparing the zoning map using GIS. Materials & Methods: Groundwater samples were collected from 20 selected stations during two seasons in 2012. The samples were filtered (0.45 ?m and maintained cool in polyethyl-ene bottles. The samples were taken for the analysis of cations, the former was acidified with HNO3 to pH lower than 2. Minor elements were determined using ICP-OES. All statistical analyses were performed using the SPSS statistical package. Also, Kriging Method was used to prepare spatial distribution maps of elements in groundwater samples. Results: The results showed that the mean concentrations of Pb, Cd, Cu and Mg in the groundwater samples during the spring were 5.60±0.66, 0.21±0.04, 32.10±2.21 and 6990.0±302.10 ppb, respectively, and the mean concentrations of these elements in the groundwater samples in the summer were 4.86±0.46, 0.30±0.08, 25.55±3.63 and 3654.05±215.65 ppb, respectively. Comparing the mean concentrations of the evaluated metals with WHO permissible limits showed a significant difference (p<0.05. Thus, the mean concentrations of the metals were significantly lower than the permissible limits. Conclusion: Although the groundwater resources of Razan Plain are not currently polluted with heavy metals, long-term excessive use of agricultural inputs and establishment of pollut-ing industries, can pose a threat to groundwater resources of this area. (Sci J Hamadan Univ Med Sci 2015; 21(4:319-329

  13. [Effects of combined pollution of Cd, Cu and Pb on antioxidant enzyme activities of earthworm in soils].

    Science.gov (United States)

    Wang, Hui; Xie, Xin-Yuan

    2014-07-01

    Recently, soil heavy metal contamination becomes more and more serious in certain areas in China. Adverse effect caused by heavy metals in contaminated soils has been a wide concern for many years. In this study, a bioassay experiment with the earthworm (Eisenia foetida) was conducted to investigate the effects of compound application of Cd, Cu and Pb in soil on surperoxide dismutase (SOD), glutathione S-transferase (GST) and acid phosphatase (AP) activity in earthworms. Through a method of greenhouse soil experiment, this study utilized a uniform design method of three factors and six levels (Cd: 0-15 mg x kg(-1), Cu: 0-175 mg x kg(-1), Pb: 0-600 mg x kg(-1)) to research the physiological property and enrichment characteristics of earthworm in soils with Cd, Cu and Pb compound pollution. The activity of SOD, GST and AP were inhibited significantly under Cd, Cu and Pb compound pollution. And they were impacted by both time and heavy metal contents in the soil. Compared with the control sample, the activity of SOD increased by 7.4% -240.5% in the first eight days under the stress of heavy metals. But owing to the extremely severe stress, it was suppressed and descended by 19.4% -69.7%. Compared with the control sample, the activity of GST increased by 104.3% -217.3% in the first sixteen days under the stress of heavy metals. But owing to the extremely severe stress, it was suppressed and descended by 1.2% - 40.3%. The activity of AP changed over time in a trend of "increase, decrease, increase, decrease". Compared with the control sample, the activity of AP decreased by 9.2% -37.8% in the first eight days, then increased by 37.2% -117.2% in sixteenth days and decreased by 24.3% -34.0% to the last day. The analysis demonstrates that Pb and Cd-Cu-Pb is the dominant factor to the activity of SOD, while Cd and Cu were the dominant factors to the activity of GST and AP.

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

    Science.gov (United States)

    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.

  15. Bioavailability of adsorbed and coprecipitated Cu, Ni, Pb, and Cd on iron and iron/aluminum hydroxide to Phragmites australis.

    Science.gov (United States)

    Wang, He; Jia, Yongfeng

    2017-01-01

    The bioavailability of heavy metals strongly depends on their speciation in the environment. Adsorption (ADS) and coprecipitation (CPT) on amorphous metal hydroxides are important processes, controlling the fates of heavy metals in an aqueous environment. This work studied the bioavailability of Cu, Cd, Ni, and Pb adsorbed on and/or coprecipitated with amorphous iron and iron/aluminum mixed hydroxides to the wetland plant Phragmites australis. After a 13-day treatment, there was an apparent uptake of the heavy metals by the plant, and the amount of metal bioaccumulation was measurably different for different association forms (ADS vs. CPT). The bioaccumulation of Cd associated with Fe0.5Al0.5(OH)3 was greater than that with Fe(OH)3; the adsorbed metals were found to be more bioavailable than the coprecipitated forms for most of the treatments while the aging treatment significantly reduced the bioaccumulation of ADS metals. In the single metal treatment, root metal concentrations in the Fe(OH)3 ADS system followed the order Ni (68 mg kg(-1)) > Cu (32 mg kg(-1)) > Cd (28 mg kg(-1)) > Pb (9 mg kg(-1)), while the CPT system followed the order of Cu (30 mg kg(-1)) > Ni (22 mg kg(-1)) > Pb (9 mg kg(-1)) > Cd (7 mg kg(-1)). The order of metal accumulation in a combined metal treatment was similar to that for single metal treatments, but observed Ni concentration declines by 22 and 71 % and Cu and Cd concentrations increase by 30 and 50 % (for CPT and ADS treatments, respectively), while Pb concentrations increased by 30~50 % in both of them. When treated with low-molecular-weight organic acids (LMWOAs), metal desorption, indicative of metal oxide bonding strength and metal bioavailability, was consistent with metal accumulation in the plant.

  16. Role of microbial inoculation and chitosan in phytoextraction of Cu, Zn, Pb and Cd by Elsholtzia splendens--a field case.

    Science.gov (United States)

    Wang, Fa Yuan; Lin, Xian Gui; Yin, Rui

    2007-05-01

    A field experiment was carried out to study the effect of microbial inoculation on heavy metal phytoextraction by Elsholtzia splendens and whether chitosan could have a synergistic effect with the microbial inocula. The microbial inocula consisted of a consortium of arbuscular mycorrhizal fungi and two Penicillium fungi. Three treatments were included: the control, inoculation with microbial inocula, and the inoculation combined with chitosan. Microbial inoculation increased plant biomass especially shoot dry weight, enhanced shoot Cu, Zn and Pb concentrations but did not affect Cd, leading to higher shoot Cu, Zn, Pb and Cd uptake. Compared with microbial inoculation alone, chitosan application did not affect plant growth but increased shoot Zn, Pb and Cd concentrations except Cu, which led to higher phytoextraction efficiencies and partitioning to shoots of Zn, Pb and Cd. These results indicated synergistic effects between microbial inocula and chitosan on Zn, Pb and Cd phytoextraction.

  17. Water Soluble Cationic Porphyrin Sensor for Detection of Hg2+, Pb2+, Cd2+, and Cu2+

    Directory of Open Access Journals (Sweden)

    Matibur Zamadar

    2016-01-01

    Full Text Available Here we report the sensing properties of the aqueous solution of meso-tetra(N-methyl-4-pyridylporphine tetrachloride (1 for simultaneous detection of toxic metal ions by using UV-vis spectroscopy. Cationic porphyrin 1 displayed different electronic absorptions in UV-vis region upon interacting with Hg2+, Pb2+, Cd2+, and Cu2+ ions in neutral water solution at room temperature. Quite interestingly, the porphyrin 1 showed that it can function as a single optical chemical sensor and/or metal ion receptor capable of detecting two or more toxic metal ions, particularly Hg2+, Pb2+, and Cd2+ ions coexisting in a water sample. Porphyrin 1 in an aqueous solution provides a unique UV-vis sensing system for the determination of Cd2+ in the presence of larger metal ions such as Hg2+, or Pb2+. Finally, the examination of the sensing properties of 1 demonstrated that it can operate as a Cu2+ ion selective sensor via metal displacement from the 1-Hg2+, 1-Pb2+, and 1-Cd2+.

  18. Isolation and characterization of heavy-metal-mobilizing bacteria from contaminated soils and their potential in promoting Pb, Cu, and Cd accumulation by Coprinus comatus.

    Science.gov (United States)

    Jing, Xiao-Bing; He, Nan; Zhang, Ying; Cao, Yan-Ru; Xu, Heng

    2012-01-01

    The enhanced effect of heavy-metal-mobilizing bacteria on the uptake of Pb, Cu, and Cd by Coprinus comatus from Pb-, Cu-, and Cd-multicontaminated soil was assessed in this study. Thirteen strains, tolerating 800 mg·L(-1) Pb, 200 mg·L(-1) Cu, and 200 mg·L(-1) Cd simultaneously were selected for heavy-metal-solubilizing experiments in soil. The mobilization of heavy metals depended on the characteristics of bacteria and heavy metals. Correlation analysis demonstrated that for Pb solubilization, the acid-producing ability was the most significant factor, while for Cu and Cd, siderophores played a leading role in this process. Four strains, based on their excellent ability to solubilize heavy metal in soil, were applied in pot experiments. The results showed that all strains can promote the growth of C. comatus and meanwhile help mushroom accumulate more heavy metals (Pb, Cd, and Cu). The maximum uptake for total Pb and Cu by C. comatus was observed in inoculations with Bacillus sp. strain JSG1 (2.02- and 2.13-fold, respectively, compared with uninoculated soil), while for Cd, it was recorded in Bacillus sp. strain PB2 treated soil (2.03-fold). Therefore, this work suggests that the mushroom-bacteria interaction can be developed into a novel bioremediation strategy.

  19. Removal of Pb(II), Cd(II), Cu(II) and trichloroethylene from water by Nanofer ZVI.

    Science.gov (United States)

    Eglal, Mahmoud M; Ramamurthy, Amruthur S

    2015-01-01

    Zero-valent iron nanoparticle (Nanofer ZVI) is a new reagent due to its unique structure and properties. Images of scanning electron microscopy/electron dispersive spectroscopy (SEM/EDS), transmission electron microscopy and X-ray diffraction revealed that Nanofer ZVI is stable, reactive and has a unique structure. The particles exhibited a spherical shape, a chain-like structure with a particle size of 20 to 100 nm and a surface area between 25-30 m2g(-1). The time interval for particles to agglomerate and settle was between 4-6 h. SEM/EDS Images showed that particle size increased to 2 µm due to agglomeration. Investigation of adsorption and oxidation behavior of Nanofer ZVI used for the removal of Cu(II), Pb(II), Cd(II) ions and trichloroethylene (TCE) from aqueous solutions showed that the optimal pH for Pb(II), Cu(II), Cd(II) and TCE removal were 4.5 and 4.8, 5.0 and 6.5, respectively. Test data were used to form Langmuir and Freundlich isotherms. The maximum contaminant loading was estimated as 270, 170, 110, 130 mg per gram of Nanofer ZVI for Cu(II), Pb(II), Cd(II) and TCE respectively. Removal of metal ions is interpreted in terms of their hydrated ionic radii and their electronegativity. TCE oxidation followed the dechlorination pathway resulting in nonhazardous by-products.

  20. Removal of As, Cd, Cu, Ni, Pb, and Zn from a highly contaminated industrial soil using surfactant enhanced soil washing

    Science.gov (United States)

    Torres, Luis G.; Lopez, Rosario B.; Beltran, Margarita

    Surfactant enhanced soil washing (SESW) was applied to an industrial contaminated soil. A preliminary characterization of the soil regarding the alkaline-earth metals, Na, K, Ca and Mg took values of 2866, 2036, 2783 and 4149 mg/kg. The heavy metals As, Cd, Cu, Pb, Ni and Zn, had values of 4019, 14, 35582, 70, 2603, and 261 mg/kg, respectively. When using different surfactants, high removal of Cu, Ni and Zn were found, and medium removals for Pb, As and Cd. In the case of these three metals, tap water removed more than the surfactant solutions, except for the case of As. There were surfactants with average removals (this is, the removal for all the metals studied) of 67.1% (Tween 80), 64.9% (Surfacpol 14104) and 61.2% (Emulgin W600). There were exceptional removals using Texapon N-40 (83.2%, 82.8% and 86.6% for Cu, Ni and Zn), Tween 80 (85.9, 85.4 and 81.5 for Cd, Zn and Cu), Polafix CAPB (79%, 83.2% and 49.7% for Ni, Zn and As). The worst results were obtained with POLAFIX LO with a global removal of 45%, well below of the average removal with tap water (50.2%).All removal efficiencies are reported for a one step washing using 0.5% surfactant solutions, except for the case of mezquite gum, where a 0.1% solution was employed.

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

    Directory of Open Access Journals (Sweden)

    M. Boye

    2012-03-01

    Full Text Available 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

  2. High efficiency CH3NH3PbI3:CdS perovskite solar cells with CuInS2 as the hole transporting layer

    Science.gov (United States)

    Chen, Chong; Zhai, Yong; Li, Fumin; Tan, Furui; Yue, Gentian; Zhang, Weifeng; Wang, Mingtai

    2017-02-01

    The CH3NH3PbI3:CdS composite films are prepared by a newly developed precursor blending solution method, which are further used to fabricate CH3NH3PbI3:CdS perovskite solar cells. Our experimental results demonstrate that the introduced CdS effectively improves the light absorption property of the ITO/CuInS2/Al2O3/CH3NH3PbI3:CdS film stack and decreases the charge recombination in the prepared solar cells due to the formation of CH3NH3PbI3/CdS bulk heterojunction. Furthermore, the formed CdS/CuInS2 heterojunction also contributes to the enhanced efficiency. As a consequence, the CH3NH3PbI3/CdS bulk heterojunction perovskite solar cells exhibit a maximum power conversion efficiency of (16.5 ± 0.2)%, which is 1.35 times the best efficiency of 12.2% of previously reported CdS/CH3NH3PbI3 bilayer solar cell. In addition, this efficiency is a 59% improvement compared with the efficiency of (10.4 ± 0.2)% for the ITO/CuInS2/Al2O3/CH3NH3PbI3/PC60BM/Ag cell without CdS.

  3. Kinetic extractions to assess mobilization of Zn, Pb, Cu, and Cd in a metal-contaminated soil: EDTA vs. citrate

    Energy Technology Data Exchange (ETDEWEB)

    Labanowski, Jerome [INRA, UR 251 Unite PESSAC, RD 10, F-78026 Versailles Cedex (France); Monna, Fabrice [ARTeHIS, UMR 5594 CNRS, Univ. de Bourgogne Centre des Sciences de la Terre, Bat. Gabriel, F-21000 Dijon (France); Bermond, Alain [AgroParis Tech., Laboratoire de Chimie Analytique, 16 rue C. Bernard, 75231 Paris Cedex 05 (France); Cambier, Philippe; Fernandez, Christelle; Lamy, Isabelle [INRA, UR 251 Unite PESSAC, RD 10, F-78026 Versailles Cedex (France); Oort, Folkert van [INRA, UR 251 Unite PESSAC, RD 10, F-78026 Versailles Cedex (France)], E-mail: vanoort@versailles.inra.fr

    2008-04-15

    Kinetic EDTA and citrate extractions were used to mimic metal mobilization in a soil contaminated by metallurgical fallout. Modeling of metal removal rates vs. time distinguished two metal pools: readily labile (Q{sub M1}) and less labile (Q{sub M2}). In citrate extractions, total extractability (Q{sub M1} + Q{sub M2}) of Zn and Cd was proportionally higher than for Pb and Cu. Proportions of Pb and Cu extracted with EDTA were three times higher than when using citrate. We observed similar Q{sub M1}/Q{sub M2} ratios for Zn and Cu regardless of the extractant, suggesting comparable binding energies to soil constituents. However, for Pb and Cd, more heterogeneous binding energies were hypothesized to explain different kinetic extraction behaviors. Proportions of citrate-labile metals were found consistent with their short-term, in-situ mobility assessed in the studied soil, i.e., metal amount released in the soil solution or extracted by cultivated plants. Kinetic EDTA extractions were hypothesized to be more predictive for long-term metal migration with depth. - Kinetically defined metal fractions mimic mobility aspects of heavy metals.

  4. Mosses as deposition estimators for heavy metals in precipitation. Deposition maps for Pb, Cd, Cu, and Zn in 1990 and 1995; Moser deposisjonsestimatorer for tungmetaller i nedboer. Deposisjonsrater for Pb, Cd, Cu og Zn i 1990 og 1995

    Energy Technology Data Exchange (ETDEWEB)

    Roeyset, O.

    1996-12-31

    Mosses can be used as biological indicators for deposition of heavy metals in precipitation as they take up most of the nutrients directly from precipitation. This report presents calculations of annual wet deposition rates for Pb, Cd, Cu, and Zn in Norway for 1990 and 1995 based on the relation between concentration of the metals in mosses and annual wet deposition. Based on data for heavy metals in mosses from nation-wide moss investigations in 1990 and 1995, including 500 points distributed all over Norway, kriging interpolation was performed to calculate annual deposition rates at a resolution of a 15 km x 15 km grid covering the entire country. Mosses were found to be good estimators for the wet deposition of the metals Pb and Cd, but not quite so good for Cu. For Zn, mosses could not be used directly and for this metal a deposition estimator was developed based on the concentration of Cd in the moss. 6 refs., 2 tabs.

  5. REMOVAL OF Cd2+, Cu2+AND Pb2+ WITH A BURKINA FASO CLAY ELIMINATION DU Cd2+, DU Cu2+ ET DU Pb2+ PAR UNE ARGILE LOCALE DU BURKINA FASO

    Directory of Open Access Journals (Sweden)

    BRAHIMA SORGHO

    2016-12-01

    Full Text Available Contamination of water by heavy metals is often linked to human, industrial and agricultural activities, and cause health and ecological problems. The objective of this study is to remove water pollutants like Cd2+, Cu2+ and Pb2+ in synthetic solutions by adsorption on clay from Burkina Faso. Electrochemical characterizations revealed that 90 % of heavy metals can be removed. Structural studies evidenced that almost all clay mineral species participate to the removal of heavy metals through different physico-chemical mechanisms namely ion exchange, complexation and precipitation.

  6. Experimental and modeling of the electrodialytic and dialytic treatment of a fly ash containing Cd, Cu and Pb

    DEFF Research Database (Denmark)

    Lima, A.T.; Ribeiro, A.B.; Rodriguez-Maroto, J.M.

    2010-01-01

    A one-dimensional model is developed for simulating the electrodialytic and dialytic treatment of a fly ash containing cadmium, copper and lead. Two experimental systems have been used, a column of ash and a stirred ash suspension. The movement of Cd, Cu and Pb has been modeled taking into account...... ionic species in the system, H+ and OH-, proceeding of the electrolysis at the electrodes, Ca2+, CO3 (=), SO4 (=), etc. proceeding from the ash and Na+ and NO3 (-), or citrate and ammonium ions incorporated as electrolyte solutions and/or as agent solution during the ash treatment. The simulation also...

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

    Science.gov (United States)

    Yantasee, Wassana; Hongsirikarn, Kitiya; Warner, Cynthia L; Choi, Daiwon; Sangvanich, Thanapon; Toloczko, Mychailo B; Warner, Marvin G; Fryxell, Glen E; Addleman, R Shane; Timchalk, Charles

    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. Detection of metal ions in urine has been problematic due to the protein competition and electrode fouling. 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 90 s of preconcentration in samples containing 25 vol.% of rat urine and 0.1 g L(-1) of DMSA-Fe3O4, the sensor could detect background level of Pb (0.5 ppb) and yielded linear responses from 0 to 50 ppb of Pb, excellent reproducibility (%RSD 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.

  8. Selective removals of heavy metals (Pb(2+), Cu(2+), and Cd(2+)) from wastewater by gelation with alginate for effective metal recovery.

    Science.gov (United States)

    Wang, Fei; Lu, Xingwen; Li, Xiao-yan

    2016-05-05

    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 10 min 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 1 h, 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 100 nm, respectively.

  9. Experimental analysis of the simultaneous uptake of the heavy metals Cd, Hg, Pb, Cu, Zn, Se in the sporophore of mushrooms. Versuche ueber die simultane Aufnahme der Schwermetalle Cd, Hg, Pb, Cu, Zn und Se in Pilzfruchtkoerper

    Energy Technology Data Exchange (ETDEWEB)

    Suehs, K.

    With mushrooms of the species Agaricus bisporus and Boletus badius the simultaneous uptake of the heavy metals Cd, Hg, Pb, Cu, Zn, and Se from soil to the sporophore was studied. To avoid misleadingly overrated enrichmentfactors when comparing the heavy metal contents of dried mushrooms and soils, a so-called transfer factor TF[sub v] which is related to the volume is put to discussion here, this factor takes account of the relatively small amount of dry matter in mushrooms and of the different composition (that means specific weight) of the soils in question. With help of these transfer factors the conclusion is derived, that essential elements show a better enrichment behaviour than biologically superfluous heavy metals, at least this is true with the insignificantly contaminated soils we investigated. With Cd as an example of a ''superfluous'' element it is shown that there is a strict proportionality of Cd concentrations in the mushrooms and the corresponding soils, thus producing a constant transfer factor. Apart from this the uptake of copper into the mushrooms is promoted (growth of the transfer factor) by a larger Cd supply, whereas the other elements under investigation (even the classical antagonist Zn) are not significantly affected. Furthermore there is evidence that with increasing heavy metal concentration (Cd) first the fructification of the thallus is supported and moreover, that increasing age of this primary fungus corresponds with an increase of heavy metals in the mushrooms. (orig.)

  10. Determination of distributions of Cd, Cu, and Pb concentrations in sediments of a Mexican reservoir to infer their environmental risk.

    Science.gov (United States)

    Barceló-Quintal, Icela Dagmar; Solís-Correa, Hugo Eduardo; Avila-Pérez, Pedro; López-Galván, Edgar; Gómez-Salazar, Sergio; García-Albortante, Julisa

    2012-07-01

    The José Antonio Alzate Dam in the State of Mexico, Mexico, receives wastewaters from domestic, industrial, and agricultural activities through the Lerma River. Chemical and physicochemical characteristics of the water were determined. Sediment has been studied in order to define the importance of its influence on the reservoir's state as a whole. The quantification of the metals, Cd, Cu, and Pb in total forms and the geochemical distribution and the chemical mobility of these metals in sediment have been established using a chemical sequential extraction scheme. The three metals showed a common characteristic, being more abundant in fraction F6 (residual), but the other fractions of the geochemical distribution were variable depending on the metal. First, the contamination level was evaluated with the results of the total metals, using the criteria of EPA, Thomas and Murdoch, and the Ontario Ministry of Environment for sediment in water bodies. Subsequently, the risk was assessed using the same criteria but considering the results of sequential extractions, where the geochemical distribution of each metal allowed a better understanding of metal portions with more influence on the risk, in which Cu and Pb presented low risk, but not Cd.

  11. Migration of Cd, Cu, Ni and Pb in low-permeable clay-type solids in presence of acid complexants

    Energy Technology Data Exchange (ETDEWEB)

    Sager, M. [Federal Office and Research Centre of Agriculture, Institute of Agro - Ecology Spargelfeldstrabe, Vienna (Austria)

    1997-12-31

    In order to predict vertical mobility of trace meta ions through low permeable subsurface layers below waste deposition sites, a series of experiments has been carried out; results show that the retardation behaviour of Cu/Cd/Pb/Ni simultaneously and continuously applied to water saturated soil columns together with dilute acids, depends on the the composition of the solid phase as well as the complexing capabilities of the liquid phase. Whereas acetic acid mainly releases Ca + Mg from the solid, oxalic acid can also dissolves large amounts of Fe + Al. The appearance of acid in the eluate is indicative for the penetration of added metals as well, but in some cases, the fastest (Ni) moves much faster than the acid itself. For weakly complexing acetic acid, buffer capacity and releasable Fe seem to be the main factors for the retardation of Cu/Cd/Pb/Ni. Addition of neutral salts (Na{sub 2} SO{sub 4}) lowers the water permeation velocity, and enlarges retardation of the tested cations

  12. Simultaneous titration of ternary mixtures of Pb(II), Cd(II) and Cu(II) with potentiometric electronic tongue detection

    OpenAIRE

    2015-01-01

    An automatic titration method is reported to resolve ternary mixtures of transition metals (Pb²⁺,Cd²⁺ and Cu²⁺) employing electronic tongue detection and a reduced number of pre-defined additions of EDTA titrant. Sensors used were PVC membrane selective electrodes with generic response to heavy-metals, plus an artificial neural network response model. Detection limits obtained were ca. 1 mg L¯¹ for the three target ions and reproducibilities 3.0 % for Pb²⁺, 4.1 % for Cd²⁺ and 5.2 % for Cu²⁺. ...

  13. Effect of biochar on the extractability of heavy metals (Cd, Cu, Pb, and Zn) and enzyme activity in soil.

    Science.gov (United States)

    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 (straw biochar significantly (P straw biochar significantly (P 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 impact on acid phosphatase activity. In conclusion, the rice straw biochar had greater potential as an amendment for reducing the bioavailability of heavy metals in soil than that of the bamboo biochar. The impact of biochar treatment on heavy metal extractability and enzyme activity varied with the biochar type, application rate, and particle size.

  14. Determination of mobile form contents of Zn, Cd, Pb and Cu in soil extracts by combined stripping voltammetry

    Energy Technology Data Exchange (ETDEWEB)

    Nedeltcheva, T. [Department of Analytical Chemistry, University of Chemical Technology and Metallurgy, 8 Kl. Ohridsi Blvd., 1756 Sofia (Bulgaria)]. E-mail: nedel@uctm.edu; Atanassova, M. [Department of Analytical Chemistry, University of Chemical Technology and Metallurgy, 8 Kl. Ohridsi Blvd., 1756 Sofia (Bulgaria); Dimitrov, J. [N. Pushkarov Institute of Soil Science and Agroecology, 7 Shosse Bankya St., 1080 Sofia (Bulgaria); Stanislavova, L. [N. Pushkarov Institute of Soil Science and Agroecology, 7 Shosse Bankya St., 1080 Sofia (Bulgaria)

    2005-01-10

    The amount of mobile forms of Zn, Pb, Cd and Cu in extracts obtained by treating soil samples with ammonium nitrate were determined by an appropriate combination of anodic and cathodic stripping voltammetry with hanging mercury drop electrode. Every analysis required three mercury drops: on the first one, zinc was determined; on the second, cadmium and lead; on the third, copper was determined. Zinc, lead and cadmium were determined by conventional differential-pulse anodic stripping voltammetry. For copper determination, adsorptive differential-pulse cathodic stripping voltammetry with amalgamation using chloride ions as a complexing agent was applied. The standard deviation of the results was from 1 to 10% depending on the metal content in the sample. Voltammetric results were in good agreement with the AAS analysis. No microwave digestion of soil extracts was necessary.

  15. Heavy Metals (Cd, Cu, Cr, Pb and Zn) in Meretrix meretrix Roding, Water and Sediments from Estuaries in Sabah, North Borneo

    Science.gov (United States)

    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…

  16. Mid-twentieth century increases in anthropogenic Pb, Cd and Cu in central Asia set in hemispheric perspective using Tien Shan ice core

    Science.gov (United States)

    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).

  17. Investigation on Fe, Mn, Zn, Cu, Pb and Cd fractions in the natural surface coating samples and surficial sediments in the Songhua River, China

    Institute of Scientific and Technical Information of China (English)

    GUO Shu-hai; WANG Xiao-li; LI YU; CHEN Jie-jiang; YANG Jun-cheng

    2006-01-01

    Natural surface coating samples (NSCSs) from the surface of shingles and surficial sediments (SSs) in the Songhua River,China were employed to investigate the relationship between NSCSs and SSs in fractions of heavy metals (Fe, Mn, Zn, Cu, Pb, and Cd) using the modified sequential extraction procedure (MSEP). The results show that the differences between NSCSs and SSs in Fe fractions were insignificant and Fe was dominantly present as residual phase (76.22% for NSCSs and 80.88% for SSs) and Fe-oxides phase (20.33% for NSCSs and 16.15% for SSs). Significant variation of Mn distribution patterns between NSCSs and SSs was observed with Mn in NSCSs mainly present in Mn-oxides phase (48.27%) and that in SSs present as residual phase (45.44%). Zn, Cu,Pb and Cd were found dominantly in residual fractions (>48%), and next in solid oxides/hydroxides for Zn, Pb and Cd and in easily oxidizable solids/compounds form for Cu, respectively. The heavy metal distribution patterns implied that Fe/Mn oxides both in NSCSs and SSs were more important sinks for binding and adsorption of Zn, Pb and Cd than organic matter (OM), and inversely,higher affinity of Cu to OM than Fe/Mn oxides in NSCSs and SSs was obtained. Meanwhile, it was found that the distributions of heavy metals in NSCSs and SSs were similar to each other and the pseudo-total concentrations of Zn, Cu, Pb and Cd in NSCSs were greater than those in SSs, highlighting the more importance for NSCSs than SSs in controlling behaviours of heavy metals in aquatic environments.

  18. Geochemical signals and source contributions to heavy metal (Cd, Zn, Pb, Cu) fluxes into the Gironde Estuary via its major tributaries.

    Science.gov (United States)

    Masson, Matthieu; Blanc, Gérard; Schäfer, Jörg

    2006-10-15

    Daily measurements of water discharges and suspended particulate matter (SPM) concentrations and monthly sampling for trace element analyses (Cd, Zn, Pb and Cu) were conducted from 1999 to 2002 on the Garonne, Dordogne and Isle Rivers, the three main tributaries of the Gironde Estuary, France. Dissolved and particulate Cd, Zn, Pb and Cu concentrations in the Isle River were generally higher than those in the Garonne River, despite the known historical polymetallic pollution affecting the Lot-Garonne River system. Even if the relatively high dissolved metal concentrations in the Isle River may be of importance for the local ecosystem, metal inputs into the estuarine and coastal zones are mainly controlled by fluvial transport via the Garonne River. Characteristic element concentration ratios (e.g., Zn/Pb) in SPM and stream sediments from the Dordogne and Isle Rivers suggest two different metal source areas with distinct geochemical signals. Low Zn/Pb ratios (Pb ratios (Pb ratios were assigned to downstream sources (e.g., vineyards), partly explaining high Zn and Cu concentrations and high Cu/Pb ratios (>0.8) in SPM. Although SPM derived from the upstream parts of the studied watersheds may greatly contribute to the observed fluvial metal transport (up to approximately 80% for Pb), the results suggest that intensive agriculture also considerably influences gross metal (e.g., Zn, Cu) fluxes into the Gironde Estuary. Relative contributions of upstream and downstream source zones may vary from one year to another reflecting hydrological variations and/or reservoir management. Monitoring fluxes and identifying distinct geochemical signals from source areas in heterogeneous watersheds may greatly improve understanding of contaminant transport to the coast.

  19. Determination of contamination levels of Pb, Cd, Cu, Ni, and Mn caused by former lead mining gallery.

    Science.gov (United States)

    Bakırdere, Sezgin; Bölücek, Cemal; Yaman, Mehmet

    2016-03-01

    In the present study, levels of metal contamination caused by former lead mining area were figured out. For this purpose, Pb, Cd, Cu, Ni, and Mn were determined not only in sediment samples taken from different places of the mining area but also in some plants taken around the mining place. In the digestion of plant samples, dry ashing procedure was applied. Flame atomic absorption spectrophotometer (FAAS) was used in the determination of analytes of interest. All the parameters in digestion and detection procedures were optimized to obtain efficient digestion and high sensitivities for analytes. Standard addition and direct calibration methods were applied to find whether there was any matrix interference to affect the determination of analytes. Mn concentration was found to be the highest for each sample analyzed. Lead concentration was found to be between 41 and 249 mg/kg in soil/sediment samples and between 2.2 and 1003 mg/kg in plant samples. The highest contamination levels for all of the analytes with the exception of Cd were found in current sediment sample.

  20. Sub-cellular partitioning of Zn, Cu, Cd and Pb in the digestive gland of native Octopus vulgaris exposed to different metal concentrations (Portugal)

    Energy Technology Data Exchange (ETDEWEB)

    Raimundo, J. [National Institute for Agronomy and Fisheries Research - IPIMAR, Av. Brasilia, 1449-006 Lisbon (Portugal)], E-mail: jraimundo@ipimar.pt; Vale, C. [National Institute for Agronomy and Fisheries Research - IPIMAR, Av. Brasilia, 1449-006 Lisbon (Portugal); Duarte, R.; Moura, I. [REQUIMTE - CQFB, Department of Chemistry, Faculty of Sciences and Technology, New University of Lisbon, Qta Torre, 2829-516 Monte da Caparica (Portugal)

    2008-02-15

    Concentrations of Zn, Cu, Cd and Pb and their sub-cellular distributions were determined in composite samples of digestive glands of the common octopus, Octopus vulgaris caught from two areas of the Portuguese coast characterised by contrasting metal contamination. Minor contents of Zn (1%), Cu (2%), Cd (6%) and Pb (7%) were found in the insoluble fraction, consisting of nuclei, mitochondria, lysosomes and microsome operationally separated from the whole digestive gland through a sequential centrifugation. A tendency for linear relationships between metal concentrations in nuclei, mitochondria, lysosomes and whole digestive gland was observed. These relationships suggest that despite low metal content organelles responded to the increasing accumulated metals, which means that detoxifying mechanism in cytosol was incomplete. Poorer correlations between microsome and whole digestive gland did not point to metal toxicity in the analysed compartments. However, the high accumulated Cd indicated that O. vulgaris is an important vehicle of this element to its predators in the coastal environment.

  1. Modeling removal of Cd, Cu, Pb, and Zn in acidic groundwater during neutralization by ambient surface waters and groundwaters

    Science.gov (United States)

    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

  2. Modeling removal of Cd, Cu, Pb, and Zn in acidic groundwater during neutralization by ambient surface waters and groundwaters

    Energy Technology Data Exchange (ETDEWEB)

    Paulson, A.J.; Balistrieri, L.

    1999-11-01

    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.

  3. Remove of Heavy Metals(Cu2+, Pb2+, Zn2+ and Cd2+) in Water Through Modified Diatomite

    Institute of Scientific and Technical Information of China (English)

    LIU Jia; WANG Hong-liang; L(U) Chun-xin; LIU Han-fei; GUO Zhi-xin; KANG Chun-li

    2013-01-01

    At present,heavy metal pollution has become a major environmental problem,influencing the survival of human and other creatures.Developing heavy metal ion adsorbents,which are environment friendly,of low cost and good performance is one of the effective means to solve heavy metal pollution.Rich low-grade diatomite mineral,as raw material,was modified with calcium carbonate to improve the adsorption properties of diatomite for heavy metal ions.The effects of dosage(m),pH,adsorbing time(t),temperature(T) and concentration of adsorbent(c) on the removal rate of heavy metal ions(Cu2+,Pb2+,Zn2+ and Cd2+) were studied.The results show that under the suitable conditions,T=15 ℃,c=1.5 mmol/L,m=10 g/L,t=60 min,in a weak acid environment,the removal effect of the four kinds of metal ions by modified diatomite is the best.

  4. The concentration and distribution of selected heavy metals (Pb, Cd, Cu and Zn) in soils collected from the rice fields of MADA in Kedah, Malaysia

    Science.gov (United States)

    Alrawiq, Nasser; Khairiah, J.; Latif, T. M.; Ismail, S. B.

    2013-11-01

    The present study was carried out to determine the concentration and distribution status of some heavy metals (Pb, Cd, Cu and Zn) in the paddy field soil fractions of MADA in the state of Kedah, Malaysia. Five replicate samples were randomly collected from five paddy fields in the MADA area of Jitra. The heavy metals in the soil were extracted using sequential extraction method that was presented by Badri and Aston [1], which consisted of four different fractions using different reagents. The first fraction of extraction is the easily leachable and freely exchangeable fraction (ELFE), which uses ammonium acetate (NH4CH3COO). The second fraction is acid reduction fraction (AR), which uses hydroxylamine chloride (NH2OH_HCl), while the third fraction of extraction called the organic oxidation fraction (OO) was carried out using the combination of hydrogen peroxide (H2O2), and ammonium acetate (NH4CH3COO). The last fraction called the resistant fraction uses concentrated nitrate acid (HNO3) and perchlorate acid (HClO4). Generally, all the paddy soils in this study contained low levels of Pb, Cd, Cu and Zn concentration compared to the other paddy soils. The result showed that the concentration of heavy metals in the studied area was in the following decreasing order i.e.: Pb < Zn < Cu < Cd. The results also showed that the concentration of heavy metals in the paddy soil fractions were mainly concentrated in the RR fraction except for Pb, which was at the highest level in the OO fraction, whilst Cd was more evenly distributed throughout the whole soil fraction. In general, Pb was the highest metal concentration found in the OO fraction followed by Zn in the RR fraction of the soil fractions.

  5. Bioavailability and Variability of Cd, Pb, Zn, and Cu Pollution in Soft Tissues and Shell of Saccostrea cucullata Collected from the Coast of Qeshm Island, Persian Gulf, Iran

    Directory of Open Access Journals (Sweden)

    Ali Kazemi

    2016-07-01

    Full Text Available Background: Marine pollution is a global environmental problem that its monitoring by ideal biomonitors is of great importance. Marine organisms, especially mussels, have the ability to accumulate metals from the environment; they can be considered as a biomonitoring agent. Methods: In this study, concentrations of heavy metals were measured in Saccostrea cucullata collected from seven sites on Qeshm Island's Coast. To achieve a digesting sample, each soft tissue was obtained and each of the shell homogeneous powders, 0.8 g and 1 g, respectively, were mixed with 10 mL HNO3 (69% and poured into a PTFE digestion vessel. The prepared samples were evaluated for Cd, Cu, and Zn by using a flame AAS Model 67OG and for Pb by using a graphite furnace AAS. Results: The distributions of metals between soft tissues and shells were compared in each sampling site. For seven sites, Cd, Zn, and Cu levels in soft tissues were higher than in the shells, but Pb level was higher in the shells than in the soft tissues. In addition, the results indicated the coefficient of variation (CV in the soft tissues was lower than the shells for Cd, and in the shells lower than the soft tissues for Pb, whereas the CV values were different in both the soft tissues and shells for Zn and Cu. Conclusion: The results of this study support using these materials in S. cucullata for biomonitoring. Shells are appropriate for monitoring Pb contamination, and the soft tissues are more apt for monitoring Cd, Zn, and Cu contamination.

  6. Extratores para Cd, Cu, Cr, Mn, Ni, Pb e Zn em LATOSSOLOS tratados com biossólido e cultivados com milho Extractants for Cd, Cu, Cr, Mn, Ni, Pb and Zn in biossolid-amanded Oxisols cultivated with corn

    Directory of Open Access Journals (Sweden)

    Ana Rosa Martins dos Anjos

    2001-06-01

    Full Text Available O uso de biossólidos (lodo de esgoto em áreas agrícolas cria uma demanda por informações sobre o extrator mais adequado para se prever disponibilidade de metais pesados, presentes nesse resíduo, para as espécies vegetais cultivadas nessas áreas. A eficiência dos extratores HCl 0,1 mol L-1, Mehlich 3 e DTPA 0,005 mol L-1 pH 7,3 e da água régia na previsão da fitodisponibilidade de metais pesados presentes em solos tratados com biossólido foi avaliada através de um experimento com milho cultivado em LATOSSOLO VERMELHO Distrófico (LVd e LATOSSOLO AMARELO Distrófico (LAd. As parcelas experimentais foram vasos com capacidade para 0,5 m³de terra, distribuídos em blocos ao acaso, em esquema fatorial 4 x 4, quatro tratamentos (LVd+lodo, LVd, LAd+lodo e LAd e quatro métodos de extração com quatro repetições. O biossólido foi aplicado antes do cultivo do milho, numa quantidade total de 388 Mg ha-1, base seca, parcelada em 5 vezes espaçadas de 2 meses cada. Antes de semear o milho foi feita a amostragem da terra a 0-0,20 m, que foi analisada para teor total dos metais presentes com água régia e teores trocáveis removidos pelos extratores: solução 0,1 mol L-1 de HCl, Mehlich 3; DTPA-TEA pH 7,3. As plantas foram separadas em folha diagnose, folhas ao final do ciclo, pendão, colmo, bainha, sabugo, palha e grãos. Apesar da quantidade de biossólido aplicada aos solos, os teores totais dos metais analisados não excederam os limites críticos estabelecidos pela United States Environmental Protection Agency (USEPA e pela Diretriz da Comunidade Européia. As correlações feitas entre teor de metais presentes nas várias partes das plantas e teores dos metais removidos pelos diferentes extratores evidenciaram que Mehlich 3 foi eficiente apenas na previsão da fitodisponibilidade de Cu e Zn. Nenhum dos extratores testados foi eficiente na previsão da disponibilidade de Cd, Cr, Ni e Pb para as plantas de milho.The use of biossolids

  7. Levels of Cd (II, Mn (II, Pb (II, Cu (II, and Zn (II in Common Buzzard (Buteo buteo from Sicily (Italy by Derivative Stripping Potentiometry

    Directory of Open Access Journals (Sweden)

    P. Licata

    2010-01-01

    Full Text Available The purpose of this study was to determine the concentrations of heavy metals (Cd, Pb, Cu, Mn, and Zn in different organs (liver, kidney, muscle, lung, skin, and feathers of buzzards (Buteo buteo, utilized as a “biological indicator” for environmental contamination, from different areas of Sicily and to investigate the relationships between birds sex, age, and weight and metal levels in these samples. All samples of common buzzards were collected at the “Recovery Center of Wild Fauna” of Palermo, through the Zooprophilactic Institute. Potentiometric stripping analysis (PSA was used to determine the content of Cd(II, Cu(II, Mn(II, Pb(II, and Zn(II in bird tissues. For toxic metals, the highest levels of Pb were in liver and those of Cd in lung; Zn levels were higher than Cu and Mn in all tissues analyzed. The concentrations in liver, lung, kidney, and muscle could be considered as an indicative of chronic exposure to metals while the presence of metals in skin could be consequential to storing and elimination processes. The found concentrations of metals in the studied matrices required a highly sensitive method for their determination and a simple sample preparation procedure, and the proposed method was well suited for this purpose.

  8. Biochar prepared from castor oil cake at different temperatures: A voltammetric study applied for Pb(2+), Cd(2+) and Cu(2+) ions preconcentration.

    Science.gov (United States)

    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.

  9. Mechanism of Cu(II), Cd(II) and Pb(II) ions sorption from aqueous solutions by macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate)

    Science.gov (United States)

    Nastasović, Aleksandra B.; Ekmeščić, Bojana M.; Sandić, Zvjezdana P.; Ranđelović, Danijela V.; Mozetič, Miran; Vesel, Alenka; Onjia, Antonije E.

    2016-11-01

    The mechanism of Cu(II), Cd(II) and Pb(II) ions sorption from aqueous solutions by macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) (PGME) functionalized by reaction of the pendant epoxy groups with diethylene triamine (PGME-deta) was studied using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis. Atomic force microscopy (AFM) and scanning energy-dispersive X-ray spectroscopy (SEM-EDX) were used for the determination of surface morphology of the copolymer particles. The sorption behavior of heavy metals Cu(II), Cd(II) and Pb(II) ions sorption was investigated in batch static experiments under non-competitive conditions at room temperature (298 K). The obtained results were fitted to pseudo-first order, pseudo-second order and intraparticle diffusion kinetic model. The kinetics studies showed that Cu(II), Cd(II) and Pb(II) sorption obeys the pseudo-second-order model under all investigated operating conditions with evident influence of pore diffusion.

  10. Soluble/insoluble (dilute-HCl-extractable fractionation of Cd, Pb and Cu in Antarctic snow and its relationship with metal fractionations in the aerosol

    Directory of Open Access Journals (Sweden)

    Annibaldi A.

    2013-04-01

    Full Text Available A chemical fractionation methodology for determination of the (water soluble and the insoluble (dilute-HCl-extractable fractions of Cd, Pb and Cu in Antarctic snow was set-up and verified for the additivity of the two fractions detected. Molten samples were filtrated and the water-insoluble fraction was extracted by dilute ultrapure HCl (pH ~1.5. Metal determinations were carried out in the two fractions by square wave anodic stripping voltammetry. The total metal concentrations in samples collected in the 2000–2001 austral summer in a clean area (Faraglione Camp in the neighbourhood of the Mario Zucchelli Italian Station were of the order of Cd 10-20 pg g−1, Pb 20–40 pg g−1, Cu 60–120 pg g−1 with an approximate equidistribution between soluble and insoluble fractions. These fractionations compare well (and show a quite consistent temporal trend with those observed in the aerosol samples collected in the same area/period and confirm the close relationship between metal distributions in snow/ice and in the aerosol. At the station metal concentrations increase due to anthropic contribution and the distribution changes with Cd predominantly present in the soluble fraction (~80%, while Pb and Cu are more concentrated in the insoluble fraction, 70–80% and ~70%, respectively.

  11. 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).

    Science.gov (United States)

    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.

  12. Contents of metals Pb, Cd, Zn and Cu in Agricultural Soils of Zagreb and Its Surroundings

    Directory of Open Access Journals (Sweden)

    Marija Romić

    1998-09-01

    The highest average cadmium content of 0.93 mg/kg Cd per designated regions was recorded in the youngest river valley along the Sava. Anomalous values were also encountered in the youngest valley along the Sava watercourse, where the average zinc content amounted to 87.08 mg/kg Zn, which are classified as highly contaminated soils. Higher copper values were determined in the hilly area of Mt. Medvednica and Pleistocene of sloping terrains, which seems to be related to the manner of land use (vineyards, gardens at private holdings.

  13. Influence of Al and the heavy metals Fe, Mn, Zn, Cu, Pb, and Cd on development and efficacy of vesicular-arbuscular mycorrhiza in tropical and subtropical plants. Einfluss von Al und den Schwermetallen Fe, Mn, Zn, Cu, Pb und Cd auf die Effizienz der VA-Mykorrhiza bei tropischen und subtropischen Pflanzen

    Energy Technology Data Exchange (ETDEWEB)

    Fabig, B.

    1982-07-08

    In greenhouse experiments the influence of Al and the heavy metals Fe, Mn, Zn, Cu, Pb, and Cd on the efficacy of VA-mycorrhizal fungi was tested with special regard to several soil pH levels and soil water regimes in different combinations. The most important results were: The inoculation led to a significantly better growth of all test plants in the presence of Al, Fe, Mn, Zn, Cu, Pb, and Cd up to a specific amount of the soil-applied element; beyond this specific limit the efficacy of the mycorrhiza was more or less inhibited depending on the element. In correlation with the growth, the nearly always better P uptake of the inoculated plants was impaired only by the highest toxic amounts of the elements. In comparison with the uninoculated plants, all the inoculated plants showed higher P and Pb concentrations. The mycorrhizal plants generally had significantly higher concentrations of the elements Al, Mn, Zn, Cu, and Cd in the roots than the uninoculated plants. Generally even toxic levels of Fe in the soil did not lead to higher Fe concentrations in the plants. Even the highest amounts of Al, Fe, Mn, Zn, and Cu did not cause microscopically visible injuries to the development of the mycorrhiza and did not impede the infection. Only the toxic levels of Pb led to a decrease of the infection rate of about 50%. Pb and Cd were the reason for morphological changes of the different developmental phases of the fungus. High amounts of Pb induced an increased formation of vesicles. The highest amounts of Cd were accompanied by the crowded occurrence of arbuscules.

  14. 2-line ferrihydrite: synthesis, characterization and its adsorption behaviour for removal of Pb(II), Cd(II), Cu(II) and Zn(II) from aqueous solutions.

    Science.gov (United States)

    Rout, K; Mohapatra, M; Anand, S

    2012-03-21

    Nano-structured 2-line ferrihydrite was synthesized by a pH-controlled precipitation technique at 90 °C. Chemical, X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman analyses confirmed the sample to be 2-line ferrihydrite. The nano nature of the prepared sample was studied by transmission electron microscopy (TEM). The surface area obtained by the Brunauer-Emmett-Teller (BET) method was 175.8 m(2) g(-1). The nanopowder so obtained was used to study its behaviour for the removal of Pb(II), Cd(II), Cu(II) and Zn(II) from aqueous solutions. The relative importance of experimental parameters such as solution pH, contact time and concentration of adsorbate on the uptake of various cations was evaluated. By increasing the pH from 2.0 to 5.5, adsorption of the four cations increased. The kinetics parameters were compared by fitting the contact time data to both linear as well as non-linear forms of pseudo-second-order models. Linear forms of both Langmuir and Freundlich models fitted the equilibrium data of all the cations except for Pb(II) which was also fitted to the non-linear forms of both the models as it gave a low R(2) value of 0.85 for the Langmuir model. High Langmuir monolayer capacities of 366, 250, 62.5 and 500 mg g(-1) were obtained for Pb(II), Cd(II), Cu(II) and Zn(II), respectively. Presence of chloride or sulfate had an adverse effect on cation adsorption. The interactive effects on adsorption from solutions containing two, three or four cations were studied. Surprisingly no Cd(II) adsorption was observed in Pb(II)-Cd(II), Pb(II)-Cd(II)-Zn(II) and Pb(II)-Cd(II)-Cu(II)-Zn(II) systems under the studied concentration range. The overall loading capacity of the adsorbent decreased in mixed cation systems. Metal ion loaded adsorbents were characterized by XRD, FTIR and Raman techniques. The high adsorption capability of the 2-lines ferrihydrite makes it a potentially attractive adsorbent for the removal of cations from aqueous solutions.

  15. Effect of heavy metals (Cu, Cd and Pb) on aspartate and alanine aminotransferase in Ruditapes philippinarum (Mollusca: Bivalvia)

    Energy Technology Data Exchange (ETDEWEB)

    Blasco, J.; Puppo, J. [Instituto de Ciencias Marinas de Andalucia, Campus Univ. Rio S. Pedro, 11510 Puerto Real, Cadiz (Spain)

    1999-02-01

    The accumulation of cadmium, copper and lead and their effects on aspartate and alanine aminotransferases in digestive gland, gills, foot and soft body in the clam Ruditapes philippinarum were examined. The animals were exposed to different concentrations: Cd (200-600 {mu}g{center_dot}l{sup -1}), Pb (350-700 {mu}g{center_dot}l{sup -1}) and Cu (10-20 {mu}g{center_dot}l{sup -1}) for 7 days. The highest concentrations were found in digestive gland for cadmium and copper, and in gills for lead, and the lowest values were observed in the foot. Aspartate aminotransferase activity (AST), in general, was not inhibited by cadmium, lead or copper during the exposure. Only in clams exposed to cadmium (600 {mu}g{center_dot}l{sup -1}, 7 days) and copper (20 {mu}g{center_dot}l{sup -1}, 5 days) were observed significant differences (P<0.05) in foot and gills, respectively, with respect to control. In the case of alanine aminotransferase activity (ALT), significant differences were observed for cadmium and lead in treated animals with respect to control. With regard to copper, a decrease in ALT was observed in gills and foot exposed to 20 {mu}g{center_dot}l{sup -1}. A significant correlation (P<0.05) was observed between ALT and metal accumulation for cadmium, copper and lead in gills. In the case of soft body, only cadmium and lead showed a significant correlation. In summary, R. philippinarum can be considered a bioindicator species for cadmium and lead accumulation and ALT could be useful as biomarker of sublethal stress for these metals in soft tissues and gills. Only gills can be considered an adequate target tissue for copper. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  16. Effects of Heavy Metal Ions (Cu2+, Pb2+ and Cd2+) on DNA Damage of the Gills, Hemocytes and Hepatopancreas of Marine Crab, Charybdis japonica

    Institute of Scientific and Technical Information of China (English)

    PAN Luqing; LIU Na; ZHANG Hongxia; WANG Jing; MIAO Jingjing

    2011-01-01

    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 μgL-1), Pb2+ (50, 250, and 500 μgL-1) and Cd2+ (5, 25, and 50μgL-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 (50μgL-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.

  17. Phytoremediation efficiency of pondweed (Potamogeton crispus in removing heavy metals (Cu, Cr, Pb, As and Cd from water of Anzali wetland

    Directory of Open Access Journals (Sweden)

    Hajar Norouznia

    2014-09-01

    Full Text Available Plant-based remediation (i.e. phytoremediation is one of the most significant eco-sustainable techniques to cope with devastating consequences of pollutants. In the present study, the potential of a wetland macrophyt (i.e. Potamogeton crispus for the phytoremediation of heavy metals (i.e. Cu, Cr, Pb, As and Cd in the Anzali wetland was evaluated. The results showed that P. crispus tends to accumulate notable amounts of Cu, Cr, Pb, As and Cd according to their assayed concentrations as follows: 8.2 µg g-1 dw, 0.97 µg g-1 dw, 6.04 µg g-1 dw, 2.52 µg g-1 dw and 0.34 µg g-1 dw, respectively. Further accurate perception of the phytoremediation efficiency were conducted using both bioconcentration factor and translocation factor. The average of the highest bioconcentration factors was presented in a descending order as: 2.9×103, 1.9×103, 1.17×103, 0.68×103 and 0.46×103 for the Cu, Cr, Pb, Cd and As, respectively. Based on the results, P. crispus presents high potential to absorb all the alluded metals except for As and partly Cd. Correspondingly, the mean values of translocation factor were reported in the range of 0.41 to 2.24. Eventually, relying on the observed findings, the results support the idea that P. crispus species would be employed as the prospective candidate for the phytoremediation processes in Anzali wetland.

  18. Cu(I), Ag(I), Cd(II), and Pb(II) binding to biomolecules studied by perturbed angular correlation of $\\gamma$-rays (PAC) spectroscopy

    CERN Multimedia

    Metal ions display diverse functions in biological systems and are essential components in both protein and nucleic acid structure and function, and in control of biochemical reaction paths and signalling. Similarly, metal ions may be used to control structure and function of synthetic biomolecules, and thus be a tool in the design of molecules with a desired function. In this project we address a variety of questions concerning both the function of metal ions in natural systems, in synthetic biomolecules, and the toxic effect of some metal ions. All projects involve other experimental techniques such as NMR, EXAFS, UV-Vis, fluorescence, and CD spectroscopies providing complementary data, as well as interpretation of the experimental data by quantum mechanical calculations of spectroscopic properties. The isotopes to be employed in the proposal are the following: $^{111m}$Cd, $^{111}$Ag, $^{199m}$Hg, $^{204m}$Pb, $^{61}$Cu, $^{68m}$Cu

  19. 小球藻吸附水体中Cd2+﹑Pb2+和Cu2+的试验研究%Experimental study on adsorption of Cd2+, Pb2+and Cu2+from water by Chlore lla v ulgaris

    Institute of Scientific and Technical Information of China (English)

    陈和祥

    2014-01-01

    In order to study the adsorption of Cd2+, Pb2+and Cu2+from water by Chlorella vulgaris, the ad‐sorption performance of freeze-dried Chlorella vulgaris in simulant heavy metal iron-containing solution was in‐vestigated on the basis of the test values of Cd2+, Pb2+ and Cu2+ in the wastewater from typical electronic waste disposal region. The results showed that, Cu concentration of the solution was higher and the pollution degree of Cd and Pb was serious. The effect of Chlorella vulgaris on Pb2+ was good with the removal rate and quantity of 88.42%and 13.262 4 mg/g respectively;the removal rate of Cu2+was lower, however, the removal quantity reached as high as 17.480 6 mg/g;the removal rate of Cd2+was higher, but the removal quantity was only 0.433 7 mg/g.%为了研究小球藻藻体吸附水体中Cd2+﹑ Pb2+和Cu2+的情况,在检测了典型电子垃圾处理区水体中重金属Cd﹑ Pb和Cu浓度的基础上,采用冷冻干燥的小球藻藻体在模拟重金属离子溶液中进行吸附试验。结果表明,水体中重金属Cu的浓度较高, Cd和Pb的污染程度较严重。藻体对于Pb2+的去除效果较好,去除率和去除量分别达到88.42%和13.2624 mg∕g; Cu2+的去除率较低,但去除量高达17.4806 mg∕g; Cd2+去除率较高,但去除量仅有0.4337 mg∕g。

  20. 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)

    Science.gov (United States)

    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).

  1. Determination of As, Cd, Cu, Hg and Pb in biological samples by modern electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Sardans, Jordi, E-mail: j.sardans@creaf.uab.ca [Ecophysiological and Global Change Unit CSIC-CREAF, Edifici C, Universitat Autonoma de Barcelona, Bellaterra 08193, Barcelona (Spain); Montes, Fernando [Departamento de Ciencias Analiticas, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/ Senda del Rey 9. 28040 Madrid (Spain); Penuelas, Josep [Ecophysiological and Global Change Unit CSIC-CREAF, Edifici C, Universitat Autonoma de Barcelona, Bellaterra 08193, Barcelona (Spain)

    2010-02-15

    of this technique that reaches figures of merit equivalent to Inductively coupled plasma mass spectrometry (ICP-MS). Herein is presented an overview of recent advances and applications of (ETAAS) for the determination of As, Cd, Cu, Hg and Pb in biological samples drawn from studies over the last decade.

  2. Evaluation of Exposure to Heavy Metals Cu, Zn, Cd and Pb in Vegetables Grown in the Olericultures of Zanjan Province\\'s Fields

    Directory of Open Access Journals (Sweden)

    L Tabande

    2016-06-01

    Full Text Available Background and Objective: The contamination of soils and plants with heavy metals is a serious and growing problem. The present study aimed to determine the concentration of heavy metals in soil and some agricultural products and the probability of risks due to their consumption. Materials and Methods: This cross-sectional descriptive study was performed using random sampling at harvest time in 2014 on 205 samples of vegetable crops (Leek, chard, parsley, watermelon, melon, tomatoes, cucumber, potatoes, onion, garlic, radish, green peas, and broad bean and 129 samples of soils under cultivation. Concentrations of Cu, Zn, Cd, and Pb in soil and plant samples were determined by an atomic absorption instrument and the data was analyzed using SPSS software. Results: There were significant differences between the mean concentrations of Pb, Cu, and Zn for different vegetables (P<0.001, but no significant difference was observed for Cd. The highest mean levels of Pb, Cd, Cu, and Zn were detected in parsley, chard, broad bean, and leek respectively. However, there was no heavy metal pollution in the remainder of the vegetables and soil samples (with the exception of agricultural soils adjacent to the lead mine of Mahneshan area studied. Hazard probability (HQ of each element for cancerous diseases was less than unit and the intake of heavy metals was lower than the Provisional Tolerable Daily Intake (PTDI. Conclusion: The results of this study indicated that major accumulation of heavy metals was obtained in leafy vegetables. Therefore, much attention should be paid to consumption of leafy vegetables, especially vegetables grown in the surrounding industrial areas.

  3. Analysis of Zn, Cd, As, Cu, Pb, and Fe in snails as bioindicators and soil samples near traffic road by ICP-OES.

    Science.gov (United States)

    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).

  4. [Biosorption of Cd(II), Cu(II), Pb(II) and Zn(II) in aqueous solutions by fruiting bodies of macrofungi (Auricularia polytricha and Tremella fuciformis)].

    Science.gov (United States)

    Mo, Yu; Pan, Rong; Huang, Hai-wei; Cao, Li-xiang; Zhang, Ren-duo

    2010-07-01

    Batch experiments were conducted to study the ability of fruiting bodies of Auricularia polytricha and Tremella fuciformis to adsorb Cd(II), Cu(II), Pb(II) and Zn(II) from aqueous solutions, including biosorption ability of the biomass to remove heavy metals from solutions with different concentrations, kinetics of adsorption, influence of co-cations, and biosorption affinity in multi-metalsystem. Results showed that in the solutions with individual metal, the maximum biosorption amounts of Cd(II), Cu(II), Pb(II), Zn(II) by A. polytricha were 18.91, 18.69, 20.33, 12.42 mg x g(-1), respectively, and the highest removal rates for all cases were more than 85%. The maximum biosorption amounts of Cd(II), Cu(II), Pb(II), Zn(II) by T. fuciformis were 19.98, 20.15, 19.16, 16.41 mg x g(-1), respectively, and highest removal rates for all cases were more than 75%. In the solutions with initial concentrations of 10, 50 and 100 mg x L(-1), the biosorption amounts increased but the removal rates decreased as the initial concentrations increasing. The pseudo-second-order reaction model described adsorption kinetics of heavy metal ions by fruiting bodies of A. polytricha and T. fuciformis better than the pseudo-first-order reaction model. In the solutions with multi metals, the biosorption amounts of heavy metals by two biosorbent were in the order of Ph(II) > Cd(II) > Cu(II) > Zn(II). The ions with more negative charges were preferential to be sorbed. The biosorption ability of A. polytricha was inhibited in multi-metal solutions. In multi-metal solutions, T. fuciformis sorbed a higher amount of Pb(II) but lower amounts of other three ions than that in the individual metal solutions. The results indicated that both fruiting bodies of A. polytricha and T. fuciformis were potential biosorbents.

  5. Optimization of simultaneous electrochemical determination of Cd(II), Pb(II), Cu(II) and Hg(II) at carbon nanotube-modified graphite electrodes.

    Science.gov (United States)

    Pikna, L'ubomír; Heželová, Mária; Kováčová, Zuzana

    2015-01-01

    The health of the environment is worsening every day. Monitoring of potentially toxic elements and remediation of environmental pollution are necessary. Therefore, the research and development of simple, inexpensive, portable and effective sensors is important. Electrochemistry is a useful component of the field of environment monitoring. The present study focuses on evaluating and comparing three types of electrodes (PIGE, PIGE/MWCNT/HNO3 and PIGE/MWCNT/EDTA/HNO3) employed for the simultaneous electrochemical determination of four potentially toxic elements: Cd(II), Pb(II), Cu(II) and Hg(II). Cyclic voltammograms were measured in an acetate buffer. The LOD, LOQ, the standard and relative precisions of the method and a prediction intervals were calculated (according to the technical procedure DIN 32 645) for the three electrodes and for each measured element. The LOD for PIGE/CNT/HNO3 (the electrode with narrowest calculated prediction intervals) was 2.98 × 10(-7) mol L(-1) for Cd(II), 4.83 × 10(-7) mol L(-1) for Pb(II), 3.81 × 10(-7) mol L(-1) for Cu(II), 6.79 × 10(-7) mol L(-1) for Hg(II). One of the benefits of this study was the determination of the amount of Hg(II) in the mixture of other elements.

  6. Removal of Heavy Metals Pb2+, Cu2+, Zn2+, Cd2+, Ni2+, Co2+ and Fe3+ from Aqueous Solutions by using Xanthium Pensylvanicum

    Directory of Open Access Journals (Sweden)

    Jaber SALEHZADEH

    2013-11-01

    Full Text Available The hazardous ill effects of heavy metals on the environment and public health is a matter of serious concern. Biosorption is emerging as a sustainable effective technology. Heavy metals in water resources are one of the most important environmental problems of countries. The intensification of industrial activity and environmental stress greatly contributes to the significant rise of heavy metal pollution in water resources making threats on terrestrial and aquatic life. The toxicity of metal pollution is slow and interminable, as these metal ions are non bio-degradable. The adsorption capacity of Xanthium Pensylvanicum towards metal ions such as Pb2+, Cu2+, Zn2+, Cd2+, Ni2+, Co2+ and Fe3+, was studied. The adsorption capacity was performed by batch experiments as a function of process parameters (such as sorption time and pH. Experimental results showed that the removal percentages increasing of metal ions at pH=4, initial concentration of metal ions 10 mg/L, and after 90 min of shaking was: Zn2+ < Cd2+ < Cu2+ < Pb2+ < Ni2+ < Fe3+ < Co2+.

  7. Cd, Pb and Cu in spring waters of the Sibylline Mountains National Park (Central Italy, determined by square wave anodic stripping voltammetry

    Directory of Open Access Journals (Sweden)

    Truzzi C.

    2013-04-01

    Full Text Available Square wave anodic stripping voltammetry (SWASV was used to determine Cd, Pb and Cu in spring waters of the Sibylline Mountains National Park, Central Italy. Samples were collected from three different areas of the Park (Mount Bove North, Mount Bove South and Springs of River Nera during the period 2004-2011. Physical-chemical parameters were also determined to obtain a general characterization of the waters. Very low metal concentrations were observed (i.e., Cd 1.3±0.4 ng L-1, Pb 13.8±5.6 ng L-1, Cu 157±95 ng L-1, well below the legal limits and also below the medians of known Italian and European data. Comparing the three areas it was noted that waters from the area of the Nera Springs are the poorest in heavy metals and the richest in minerals, that conversely the waters of Mt. Bove North are the richest in heavy metals and the poorest in mineral salts, and finally that intermediate values both for heavy metals and mineral salts were observed for the waters of Mt. Bove South.

  8. Photo-transformation of pedogenic humic acid and consequences for Cd(II), Cu(II) and Pb(II) speciation and bioavailability to green microalga.

    Science.gov (United States)

    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.

  9. Effect of EDTA, EDDS, NTA and citric acid on electrokinetic remediation of As, Cd, Cr, Cu, Ni, Pb and Zn contaminated dredged marine sediment.

    Science.gov (United States)

    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.

  10. pH effects on the removal of Cu{sup 2+}, Cd{sup 2+} and Pb{sup 2+} from aqueous solution by waste brewery biomass

    Energy Technology Data Exchange (ETDEWEB)

    Marques, P.A.S.S.; Rosa, M.F. [Departamento de Energias Renovaveis, Inst. Nacional de Engenharia e Tecnologia Industrial, Lisboa (Portugal); Pinheiro, H.M. [Centro de Engenharia Biologica e Quimica, Inst. Superior Tecnico, Lisboa (Portugal)

    2000-08-01

    An industrial strain of Saccharomyces cerevisiae collected from the waste of a brewing industry was used to remove lead, cadmium and copper from aqueous solutions (1 mm).Metal removal efficiency by using either biomass suspension directly diluted into the metal solutions or biomass previously incubated and washed in distilled water was compared. In all experiments with unwashed biomass a shift in the medium pH from 4.5 to a final value in the 7.0-8.0 range occurred. This pH increase was responsible for a metal precipitation effect associated to the metal biosorption. A very different pH profile was observed when washed biomass was used leading to different removal profiles for Cd{sup 2+} and Pb{sup 2+} and a similar one for Cu{sup 2+}. In the absence of biomass, medium components and/or the excreted intracellular products proved to interfere in the metal removal and to be responsible for 80% Pb{sup 2+} precipitation, in the pH 4.5-5.0 range.To initial metal solution pH, leading to the lowest residual ion concentrations, after 96 h of contact with unwashed biomass and in the absence of pH adjustment, was 4.5-5.0. Continuous or stepwise adjustment of medium pH to this range during the process was unfavourable for metal removal, being the continuous adjustment the worst procedure. In this case, Cd{sup 2+} was not biosorbed and Cu{sup 2+} removal decreased from 76 to 33%. However, Pb{sup 2+} was always extensively removed (89%) and only slightly affected by pH control.The global results suggest different removal mechanisms for each cation. Cu{sup 2+} was removed by both metal sorption and precipitation, due to the pH shift that occurred during the process, while Cd{sup 2+} removal showed to be completely dependent of this pH shift. Pb{sup 2+} was totally and quickly removed, by precipitation, in the presence of the biomass suspension and at pH 4.5.Moreover, the biosorbent changes occurring during the process played an important role in the metal removal when non

  11. Effects of Cd, Pb, Zn, Cu-resistant endophytic Enterobacter sr CBSB1 and Rhodotorula sp. CBSB79 on the growth and phytoextraction of Brassica plants in multimetal contaminated soils.

    Science.gov (United States)

    Wang, Wenfeng; Deng, Zujun; Tan, Hongming; Cao, Lixiang

    2013-01-01

    To survey the effects of endophytic Enterobacter sp. CBSB1 and Rhodotorula sp. CBSB79 resistant to Cd2+, Pb2+, Zn2+, and Cu2+ on the growth and phytoextraction of Brassica, the endophytes were isolated by surface- sterilized methods and characterized. The CBSB1 significantly increased 44.2% of the dry weight of Brassica napus in the multimetal contaminated soil (P Enterobacter sp. CBSB1, the yeast Rhodotorula sp CBSB79 showed higher potentials to improve extraction efficacy of Cd, Pb, Zn, and Cu by Brassica seedlings in the field.

  12. Concentrations of As, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, Pb, and Zn in uruguayan rice determined by atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Mario E. Rivero Huguet

    2011-04-01

    Full Text Available The United Nations General Assembly declared the year 2004 the International Year of Rice and the concept "Rice is life". The largest nutritional problems occurring globally are protein-energy malnutrition, and Ca, Fe, I, Zn, and vitamin A deficiency. In this report, 49 rice samples (Oryza sativa L. were digested by dry ashing in order to determine As, Cd, Cr, and Pb by ETA-AAS; while Ca, Co, Cu, Fe, K, Mg, Mo, Mn, Na, Ni, and Zn were determined by FAAS; and Hg by CV-AAS using microwave-assisted decomposition. The following concentration ranges were obtained for Ca (9.1-15 mg/100 g, Cd (2.30-4.12 µg/kg, Co (41-60 µg/kg, Cu (1.33-180 mg/kg, Fe (4.41-7.15 mg/kg, K (167-217 mg/100 g, Mg (45-121 mg/100 g, Mo (0.52-0.97 mg/kg, Mn (5.45-25.4 mg/kg, Na (0.95-2.50 mg/100g, Ni (0.53-0.72 mg/kg, and Zn (5.86-12.6 mg/kg. Mean recoveries of elements from fortified rice were: 87±12% for As, 95.3±8.9% for Ca, 106.2±7.7% for Cd, 103.3±6.5% for Co, 89.4±8.1% for Cr, 99.3±4.6% for Cu, 103±10% for Fe, 96.3±9.3% for Hg, 95.4±12% for K, 98.3±8.0% for Mg, 93.4±7.8% for Mo, 95.3±9.9% for Mn, 89±12% for Na, 90.3±9.7% for Ni, 91.2±5.5% for Pb and 92.0±9.4% for Zn. The concentrations of the minerals and microelements studied fall within the typical range of rice grown around the world. Potassium was the most abundant mineral, followed by Mg and Ca; among microelements, the concentrations of Cu, Fe, Mo, Mn, Na, and Zn in rice were outstanding. It was also found that the milling process highly affects the K, Mg, Mn, Na, and Zn concentrations, while it has little influence on Ca, Co, Cu, and Fe. On the other hand, there is a loss of Ca, Fe, and Mn during the parboiling process. Recent studies have shown the potential to exploit the genetic variation of rice seeds with regard to the concentration of some minerals (Ca, Fe, Zn, etc. without affecting yield or adding new traits. All rice samples tested showed lower levels of As, Cd, Hg, and Pb in comparison

  13. 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)

    Energy Technology Data Exchange (ETDEWEB)

    Annibaldi, A.; Truzzi, C.; Illuminati, S.; Bassotti, E.; Scarponi, G. [Polytechnic University of Marche - Ancona, Department of Marine Science, Ancona (Italy)

    2007-02-15

    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 {mu}g g{sup -1} (average 4.7 {mu}g g{sup -1}), Pb 13.2-81 {mu}g g{sup -1} (average 33 {mu}g g{sup -1}), Cu 126-628 {mu}g g{sup -1} (average 378 {mu}g g{sup -1}). In terms of atmospheric concentration, the values were: Cd 0.55-6.3 pg m{sup -3} (average 3.4 pg m{sup -3}), Pb 8.7-48 pg m{sup -3} (average 24 pg m{sup -3}), Cu 75-365 pg m{sup -3} (average 266 pg m{sup -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 ({proportional_to}10% and {proportional_to}5%, respectively), while there is an evident although not

  14. Accumulation of Trace Metal Elements (Cu, Zn, Cd, and Pb) in Surface Sediment via Decomposed Seagrass Leaves: A Mesocosm Experiment Using Zostera marina L.

    Science.gov (United States)

    Hosokawa, Shinya; 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.

  15. Accumulation of Trace Metal Elements (Cu, Zn, Cd, and Pb in Surface Sediment via Decomposed Seagrass Leaves: A Mesocosm Experiment Using Zostera marina L.

    Directory of Open Access Journals (Sweden)

    Shinya Hosokawa

    Full Text Available 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.

  16. Speciation and fractionation of heavy metals in soil experimentally contaminated with Pb, Cd, Cu and Zn together and effects on soil negative surface charge

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Speciation of heavy metals in soil subsamplesexperimentally loaded with Pb, Cd, Cu and Zn in orthogonal designwas investigated by sequential extraction, and operationallydefined as water-soluble and exchangeable(SE), weakly specificadsorbed(WSA), Fe and Mn oxides-bound(OX) and organic-bound(ORG).The results show that speciation of heavy metals in the soilsubsamples depended on their kinds. About 90% of Cd and 75% of Znexisted in soil subsamples in the SE fraction. Lead and Cu existedin soil subsamples as SE, WSA and OX fractions simultaneously,although SE was still the major fraction. Organic-bound heavymetals were not clearly apparent in all the soil subsamples. Theconcentration of some heavy metal speciation in soil subsamplesshowed good correlation with ionic impulsion of soil, especiallyfor the SE fraction. Continuous saturation of soil subsamples with0.20 mol/L NH4Cl, which is the first step for determination of thenegative surface charge of soil by the ion retention method, resulted in desorption of certain heavy metals from the soil. Itwas found that the percentage desorption of heavy metals from soilsubsamples depended greatly on pH, the composition and originalheavy metal content of the soil subsamples. However, most of theheavy metals in the soil subsamples were still retained aftermultiple saturation. Compared with the parent soil, the negativesurface charge of soil subsamples loaded with heavy metals did notshow differ significantly from that of the parent one bystatistical analysis. Heavy metals existed in the soil subsamplesmainly as exchangeable and precipitated simultaneously.

  17. Hassle free synthesis of nanodimensional Ni, Cu and Zn sulfides for spectral sensing of Hg, Cd and Pb: A comparative study

    Science.gov (United States)

    Ansari, Zarina; Singha, Shib Shankar; Saha, Abhijit; Sen, Kamalika

    2017-04-01

    A simple room temperature synthesis method of Ni, Cu and Zn sulfide nanoparticles (NPs) in aqueous medium is reported here. The NPs stabilized in aqueous medium by the citrate ions were characterized by UV-vis, ζ potentials, TEM and Raman spectroscopic techniques. The solid NPs could be isolated from the aqueous medium when allowed to stand for a prolonged time ( 20 h). The solids were also characterized by IR and powder X-ray analysis. The nanoparticles were further used for the development of facile optical sensing and detection of heavy metal ions at trace scale. Alterations in the absorption spectra of the generated NPs were indicative of their interactions with heavy metal ions. Raman spectral measurements further validate the detection technique. It is found that out of the three synthesized nanoparticles, nickel sulfide NP is a specific sensor for mercury ions whereas zinc sulfide and copper sulfide NPs act as sensors for Hg2 +, Cd2 + and Pb2 +.

  18. Concentrations of Mn, Fe, Cu, Zn, Cr, Cd, Pb, Ni in selected Nigerian tubers, legumes and cereals and estimates of the adult daily intakes.

    Science.gov (United States)

    Akinyele, I O; Shokunbi, O S

    2015-04-15

    This study was designed to determine the levels of microminerals (manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), chromium (Cr)) and heavy metals (cadmium (Cd), lead (Pb) and nickel (Ni)) in some tubers, legumes and cereals obtained from the markets in Abeokuta city, South-West Nigeria. The food samples were digested by dry ashing procedure and their minerals were determined by atomic absorption spectrophotometer. The results show mean values of 1.67-32.00, 7.25-61.58, 1.59-10.56, 6.65-46.99, 0.02-0.58, legumes and cereals from various parts of the world. The daily intakes of the metals through tubers, legumes and cereals were found to be lower than the provisional tolerable daily intakes proposed by Joint FAO/WHO Expert Committee on Food Additives.

  19. Removal of divalent heavy metals (Cd, Cu, Pb, and Zn) and arsenic(III) from aqueous solutions using scoria: kinetics and equilibria of sorption.

    Science.gov (United States)

    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.

  20. Assessment of heavy metals/metalloid (As, Pb, Cd, Ni, Zn, Cr, Cu, Mn) concentrations in edible fish species tissue in the Pearl River Delta (PRD), China.

    Science.gov (United States)

    Leung, H M; Leung, A O W; Wang, H S; Ma, K K; Liang, Y; Ho, K C; Cheung, K C; Tohidi, F; Yung, K K L

    2014-01-15

    The major aim of this study was to investigate heavy metal content of edible fish in the PRD. Eleven species of fish (consisting of 711 individuals) [catfish (Clarias fuscus), tilapia (Oreochromis mossambicus), grass carp (Ctenopharyngodon idellus), bighead carp (Aristichthys nobilis), mandarin fish (Siniperca kneri), snakehead (Channa asiatiea), black bass (Micropterus salmoides), mangrove snapper (Lutjanus griseus), star snapper (Lutjanu stellatus), snubnose pompano (Trachinotus blochii) and orange-spotted grouper (Epinephelus coioides)] were collected for the analyses of heavy metals. Overall concentrations (mg/kg, ww) in the fish muscles were: As (0.03-1.53), Pb (0.03-8.62), Cd (0.02-0.06), Ni (0.44-9.75), Zn (15.7-29.5), Cr (0.22-0.65), Cu (0.79-2.26), Mn (0.82-6.91). Significant level of Pb were found in tilapia at all locations. It is recommended that heavy metal concentrations in different fish species must be determined on a regular basis in the future so as to reduce human health risks from acute and chronic food intoxication.

  1. Competition from Cu(II), Zn(II) and Cd(II) in Pb(II) binding to Suwannee River Fulvic Acid

    NARCIS (Netherlands)

    Chakraborty, P.; Chakrabarti, C.L.

    2008-01-01

    This is a study of trace metal competition in the complexation of Pb(II) by well-characterized humic substances, namely Suwannee River Fulvic Acid (SRFA) in model solutions. It was found that Cu(II) seems to compete with Pb(II) for strong binding sites of SRFA when present at the same concentration

  2. Environmental behaviors and potential ecological risks of heavy metals (Cd, Cr, Cu, Pb, and Zn) in multimedia in an oilfield in China.

    Science.gov (United States)

    Hu, Yan; Wang, Dazhou; Li, Yu

    2016-07-01

    The environmental behaviors of five heavy metals (Cd, Cr, Cu, Pb, and Zn) in a Chinese oilfield were investigated using a steady-state multimedia aquivalence (SMA) model. The modeling results showed good agreement with the actual measured values, with average residual errors of 0.69, 0.83, 0.35, 0.16, and 0.54 logarithmic units for air, water, soil, sediment, and vegetation compartments, respectively. Model results indicated that most heavy metals were buried in sediment, and that transfers between adjacent compartments were mainly deposition from the water to the sediment compartment (48.59 %) and from the air to the soil compartment (47.74 %) via atmospheric dry/wet deposition. Sediment and soil were the dominant sinks, accounting for 68.80 and 25.26 % of all the heavy metals in the multimedia system, respectively. The potential ecological risks from the five heavy metals in the sediment and soil compartments were assessed by the potential ecological risk index (PERI). The assessment results demonstrate that the heavy metals presented low levels of ecological risk in the sediment compartment, and that Cd was the most significant contributor to the integrated potential ecological risk in the oilfield. The SMA model provided useful simulations of the transport and fate of heavy metals and is a useful tool for ecological risk assessment and contaminated site management.

  3. Accumulation of Cr, Cd, Pb, Cu, and Zn by plants in tanning sludge storage sites: opportunities for contamination bioindication and phytoremediation.

    Science.gov (United States)

    Yuan, Yongqiang; Yu, Shen; Bañuelos, G S; He, Yunfeng

    2016-11-01

    Tanning sludge enriched with high concentrations of Cr and other metals has adverse effects on the environment. Plants growing in the metalliferous soils may have the ability to cope with high metal concentrations. This study focuses on potentials of using native plants for bioindication and/or phytoremediation of Cr-contaminated sites. In the study, we characterized plants and soils from six tanning sludge storage sites. Soil in these sites exhibited toxic levels of Cr (averaged 16,492 mg kg(-1)) and other metals (e.g., 48.3 mg Cu kg(-1), 2370 mg Zn kg(-1), 44.9 mg Pb kg(-1), and 0.59 mg Cd kg(-1)). Different metal tolerance and accumulation patterns were observed among the sampled plant species. Phragmites australis, Zephyranthes candida, Cynodon dactylon, and Alternanthera philoxeroides accumulated moderate-high concentrations of Cr and other metals, which could make them good bioindicators of heavy metal pollution. High Cr and other metal concentrations (e.g., Cd and Pb) were found in Chenopodium rubrum (372 mg Cr kg(-1)), Aster subulatus (310 mg Cr kg(-1)), and Brassica chinensis (300 mg Cr kg(-1)), being considered as metal accumulators. In addition, Nerium indicum and Z. candida were able to tolerate high concentrations of Cr and other metals, and they may be used as preferable pioneer species to grow or use for restoration in Cr-contaminated sites. This study can be useful for establishing guidelines to select the most suitable plant species to revegetate and remediate metals in tanning sludge-contaminated fields.

  4. Influence of different mineral and Organic pesticide treatments on Cd(II), Cu(II), Pb(II), and Zn(II) contents determined by derivative potentiometric stripping analysis in Italian white and red wines.

    Science.gov (United States)

    Salvo, Francesco; La Pera, Lara; Di Bella, Giuseppa; Nicotina, Mariano; Dugo, Giacomo

    2003-02-12

    This paper deals with the use of derivative potentiometric stripping analysis (dPSA) as a rapid and precise method to determine Cd(II), Cu(II), Pb(II), and Zn(II) levels in red and white wine samples from Sicily, Campania, and Tuscany and to investigate the possible connection between the content of these metals and the pesticide treatments used in vine-growing to control plant diseases and pests. dPSA allowed direct quantitation of heavy metals in acidified wines without any sample pretreatment. Mean recoveries of Cd(II), Cu(II), Pb(II), and Zn(II) ranged from 95.5 to 99.2% for white wine samples and from 96.1 to 100.0% for red wine samples. The obtained results showed that Cd(II) was not found in any sample and that Cu(II), Pb(II), and Zn(II) levels were always lower than the toxicity limits in both fungicide- and water-treated wines. Nevertheless, the contents of metals were increased in samples from organic and inorganic pesticides treatment with respect to the water-treated samples. In particular, quinoxyfen, dinocap-penconazole, and dinocap applications considerably increased Cu(II) and Zn(II) contents in white and red wines. The levels of lead were significantly raised by azoxystrobin and sulfur treatments.

  5. Modelling removal mechanisms of Pb, Cu, Zn and Cd in acidic groundwater during the neutralization by ambient surface and ground waters

    Science.gov (United States)

    Paulson, Anthony J.; Balistrieri, Laurie S.

    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.

  6. Removal of Pb(II), Cu(II), and Cd(II) from aqueous solutions by biochar derived from KMnO4 treated hickory wood.

    Science.gov (United States)

    Wang, Hongyu; Gao, Bin; Wang, Shenseng; Fang, June; Xue, Yingwen; Yang, Kai

    2015-12-01

    In this work, a novel approach was developed to prepare an engineered biochar from KMnO4 treated hickory wood through slow pyrolysis (600°C). Characterization experiments with various tools showed that the engineered biochar surface was covered with MnOx ultrafine particles. In comparison to the pristine biochar, the engineered biochar also had more surface oxygen-containing functional groups and much larger surface area. Batch sorption experiments showed that the engineered biochar had strong sorption ability to Pb(II), Cu(II), and Cd(II) with maximum sorption capacities of 153.1, 34.2, and 28.1mg/g, respectively, which were significantly higher than that of the pristine biochar. Batch sorption experiments also showed that the dosage, initial solution pH, and ionic strength affected the removal of the heavy metals by the biochars. The removal of the metals by the engineered biochar was mainly through surface adsorption mechanisms involving both the surface MnOx particles and oxygen-containing groups.

  7. The evaluation of growth and phytoextraction potential of Miscanthus x giganteus and Sida hermaphrodita on soil contaminated simultaneously with Cd, Cu, Ni, Pb, and Zn.

    Science.gov (United States)

    Kocoń, Anna; Jurga, Beata

    2017-02-01

    One of the cheapest, environmentally friendly methods for cleaning an environment polluted by heavy metals is phytoextraction. It builds on the uptake of pollutants from the soil by the plants, which are able to grow under conditions of high concentrations of toxic metals. The aim of this work was to assess the possibility of growing and phytoextraction potential of Miscanthus x giganteus and Sida hermaphrodita cultivated on two different soils contaminated with five heavy metals simultaneously: Cd, Cu, Ni, Pb, and Zn. A 3-year microplot experiment with two perennial energy crops, M. x giganteus and S. hermaphrodita, was conducted in the experimental station of IUNG-PIB in Poland (5° 25' N, 21° 58 'E), in the years of 2008-2010. Miscanthus was found more tolerant to concomitant soil contamination with heavy metals and produced almost double biomass than Sida in all three tested years, independent of soil type. Miscanthus collected greater amount of heavy metals (except for cadmium) in the biomass than Sida. Both energy crops absorb high levels of zinc, lower levels of lead, copper, and nickel, and absorbed cadmium at least, generally more metals were taken from the sandy soil, where plants also yielded better. Photosynthesis net rate of Miscanthus was on average 40% higher compared to Sida. Obtained results indicate that M. x giganteus and S. hermaphrodita can successfully be grown on moderately contaminated soil with heavy metals.

  8. Investigation of heavy metal (Cu, Pb, Cd, and Cr) stabilization in river sediment by nano-zero-valent iron/activated carbon composite.

    Science.gov (United States)

    Chen, Wei-fang; Zhang, Jinghui; Zhang, Xiaomao; Wang, Weiya; Li, Yuxiang

    2016-01-01

    Nano-zero-valent iron/activated carbon (nZVI/AC) composite was evaluated for its effectiveness in the stabilization of Cu, Pb, Cd, and Cr in dredged river sediment. Synthetic precipitation leaching procedure (SPLP) and toxicity characteristic leaching procedure (TCLP) were adopted to compare the effects of nZVI/AC dosage, particle size, time duration, and temperature on heavy metal leachability. The results show that leachability dropped considerably with the addition of nZVI/AC and powdered particles in the size of 0.075-0.18 mm was more effective in stabilization than granular ones. Stabilization effect was stable in long-term and robust against changes in temperature. Tessier sequential extraction revealed that heavy metals were associated with solid particle, inorganic or organic matters in sediment. The addition of nZVI/AC was able to convert relatively weakly bound heavy metals into more strongly bound species and thus reduce the bioavailability and toxicity. Also, the standard potential of heavy metals may decide the mechanism of stabilization process.

  9. Influence of Ca/Mg ratio on phytoextraction properties of Salix viminalis I. The effectiveness of Cd, Cu, Pb, and Zn bioaccumulation and plant growth.

    Science.gov (United States)

    Mleczek, Mirosław; Kozlowska, Monika; Kaczmarek, Zygmunt; Chadzinikolau, Tamara; Golinski, Piotr

    2012-01-01

    Phytoremediation and its efficiency--influenced by several factors-is prime concern in reduction of environment contamination with heavy metals. The aim of the study was to estimate in controlled conditions--in relation to the natural Ca/Mg ratio 4:1--the influence of different Ca/Mg ratios (1:1/4, 20:1, 1:10) on selected heavy metals (Cd, Cu, Pb, and Zn) accumulation efficiency shown by three morphological parts of Salix viminalis 'Cinamomea' (cane bark, shoots and roots). Accumulation of heavy metals in experimental conditions was significantly Ca/Mg ratio dependent, and occurred in the following order: 1:10 > 4:1 > 20:1 > 1:1/4. The highest accumulation under 0.5 mM solutions (as compared to 0.1 mM) was noted for copper and zinc, and the lowest for cadmium. Biometric parameters of Salix viminalis cuttings revealed the highest biomass productivity under 20:1 and 4:1 Ca/Mg ratios. In the case of shoot length increase, both metal concentration and kind of metal present in the solution were important. The results indicate that higher calcium ion concentration in solution (Ca/Mg 20:1) stimulates Salix viminalis growth by 3 fold when compared to other Ca/Mg ratio. It can be an important factor in remediation of the environment with this plant.

  10. Temporal trends of Cd, Cu, Hg, Pb and Zn in mussel (Mytilus galloprovincialis) from the Spanish North-Atlantic coast 1991-1999.

    Science.gov (United States)

    Besada, V; Fumega, J; Vaamonde, A

    2002-04-15

    Temporal trends for heavy metals (Cd, Cu, Hg, Pb and Zn) in mussel (Mytilus galloprovincialis) from the Galician and Cantabrian areas in Spain, where samples were yearly collected from 1991 to 1999, are presented. This study was carried out by the Centro Oceanográfico de Vigo of the Instituto Español de Oceanografia (I.E.O.) as part of the Spanish contribution to the Joint Assessment and Monitoring Programme (JAMP) of the OSPAR Convention. The experimental work and subsequent statistical treatment, following OSPAR procedures and guidelines, are described. In order to carry out the statistical treatment of the data, median values of the different shell length classes were used for each contaminant, year and area. The Kendall T-b correlation coefficient was used with the purpose of demonstrating the existence of a downward significant temporal trend in the pollution levels, according to the advice of ICES Working Group on Statistical Aspects of Environmental Monitoring. A decrease of copper levels was detected in Vigo, Pontevedra and Arosa, of mercury in Pontevedra and A Coruña, of lead in Vigo, Pontevedra, A Coruña and Bilbao and of zinc in Pontevedra and A Coruña. However, a cadmium positive trend was registered at Ria de Vigo. No significant trends were detected in the other cases.

  11. The Uptake Mechanism of Cd(II, Cr(VI, Cu(II, Pb(II, and Zn(II by Mycelia and Fruiting Bodies of Galerina vittiformis

    Directory of Open Access Journals (Sweden)

    Dilna Damodaran

    2013-01-01

    Full Text Available Optimum concentrations of heavy metals like copper, cadmium, lead, chromium, and zinc in soil are essential in carrying out various cellular activities in minimum concentrations and hence help in sustaining all life forms, although higher concentration of these metals is lethal to most of the life forms. Galerina vittiformis, a macrofungus, was found to accumulate these heavy metals into its fleshy fruiting body in the order Pb(II > Cd(II > Cu(II > Zn(II > Cr(VI from 50 mg/kg soil. It possesses various ranges of potential cellular mechanisms that may be involved in detoxification of heavy metals and thus increases its tolerance to heavy metal stress, mainly by producing organic acids and phytochelatins (PCs. These components help in repairing stress damaged proteins and compartmentalisation of metals to vacuoles. The stress tolerance mechanism can be deduced by various analytical tools like SEM-EDX, FTIR, and LC-MS. Production of two kinds of phytochelatins was observed in the organism in response to metal stress.

  12. Sensitive determinations of Cu, Pb, Cd, and Cr elements in aqueous solutions using chemical replacement combined with surface-enhanced laser-induced breakdown spectroscopy.

    Science.gov (United States)

    Yang, X Y; Hao, Z Q; Li, C M; Li, J M; Yi, R X; Shen, M; Li, K H; Guo, L B; Li, X Y; Lu, Y F; Zeng, X Y

    2016-06-13

    In this study, chemical replacement combined with surface-enhanced laser-induced breakdown spectroscopy (CR-SENLIBS) was for the first time applied to improve the detection sensitivities of trace heavy metal elements in aqueous solutions. Utilizing chemical replacement effect, heavy metal ions in aqueous solution were enriched on the magnesium alloy surface as a solid replacement layer through reacting with the high chemical activity metallic magnesium (Mg) within 1 minute. Unitary and mixed solutions with Cu, Pb, Cd, and Cr elements were prepared to construct calibration curves, respectively. The CR-SENLIBS showed a much better detection sensitivity and accuracy for both unitary and mixed solutions. The coefficients of determination R2 of the calibration curves were above 0.96, and the LoDs were of the same order of magnitude, i.e., in the range of 0.016-0.386 μg/mL for the unitary solution, and in the range of 0.025-0.420 μg/mL for the mixed solution. These results show that CR-SENLIBS is a feasible method for improving the detection sensitivity of trace element in liquid sample, which definitely provides a way for wider application of LIBS in water quality monitoring.

  13. Effect of EDTA and Tannic Acid on the Removal of Cd, Ni, Pb and Cu from Artificially Contaminated Soil by Althaea rosea Cavan.

    Science.gov (United States)

    Cay, Seydahmet; Uyanik, Ahmet; Engin, Mehmet Soner; Kutbay, Hamdi Guray

    2015-01-01

    In this study an ornamental plant of Althaea rosea Cavan was investigated for its potential use in the removal of Cd, Ni, Pb and Cu from an artificially contaminated soil. Effect of two different chelating agents on the removal has also been studied by using EDTA (ethylenediaminetetracetic acid) and TA (tannic acid). Both EDTA and TA have led to higher heavy metal concentration in shoots and leaves compared to control plants. However EDTA is generally known as an effective agent in metal solubilisation of soil, in this study, TA was found more effective to induce metal accumulation in Althaea rosea Cavan under the studied conditions. In addition to this, EDTA is toxic to some species and restraining the growth of the plants. The higher BCF (Bio Concentration Factor) and TF (Translocation Factor) values obtained from stems and leaves by the effects of the chemical enhancers (EDTA and TA) show that Althaea rosea Cavan is a hyper accumulator for the studied metals and may be cultivated to clean the contaminated soils.

  14. Preconcentration of Cu(II), Cd(II) and Pb(II) on Amberlite XAD-4 resin functionalized with N,N'-bis(o-vanillinidene)-ethylenediamine and their determination by FAAS in water samples.

    Science.gov (United States)

    Efendioğlu, Ayşegül; Yağan Aşcı, Mehtap; Batı, Bekir

    2010-01-01

    A new polystyrene divinylbenzene-based chelating resin was synthesized by functionalizing Amberlite XAD-4 with N,N'-bis(o-vanillinidene)ethylenediamine. This resin was capable of preconcentrating Cu(II), Cd(II) and Pb(II) in water samples prior to FAAS determination. Various parameters, such as the pH, eluent type and concentration, volume of the eluent and the sample, and diverse ion effects have been studied. The recoveries for the analytes under the optimum working conditions were higher than 95%. The accuracy of the method was tested with standard reference materials (MBH-C31XB20, GBW-02703 and CRM BCR-32) and Cd(II), Cu(II) and Pb(II) standard solutions. The method was successfully applied to water samples.

  15. A transferable force field for CdS-CdSe-PbS-PbSe solid systems

    NARCIS (Netherlands)

    Fan, Zhaochuan; Koster, Rik S.; Wang, Shuaiwei; Fang, Changming; Yalcin, Anil O.; Tichelaar, Frans D.; Zandbergen, Henny W.; van Huis, Marijn A.; Vlugt, Thijs J. H.

    2014-01-01

    A transferable force field for the PbSe-CdSe solid system using the partially charged rigid ion model has been successfully developed and was used to study the cation exchange in PbSe-CdSe heteronanocrystals [A. O. Yalcin et al., "Atomic resolution monitoring of cation exchange in CdSe-PbSe heterona

  16. Study on the distributions of Cd, Co, Sr, Zn, Ag, Cu, Pb, Mn and Ni in the eolian sands of the Gavkuni playa (southeast of Isfahan

    Directory of Open Access Journals (Sweden)

    Hamidreza Pakzad

    2014-11-01

    Full Text Available Introduction Heavy metals are continually introduced into hydrosphere, atmosphere and biosphere. These potentially toxic elements can concentrate in sediments in aqueous ecosystems and they can act as pollution sources in particular conditions. Heavy metals mainly concentrate in fine sand particles because of more concentration of heavy minerals in this grain size. The Gavkhuni playa lake with an approximate area of 550 km2 is located at southeast of Isfahan, Iran. The Zayandehrud permanent river and several seasonal rivers flow into this playa. During quaternary, massive volume of sediments in sand and gravel sizes were carried into this area and deposited. These sediments are mainly deposited in the delta of Zayandehrud river (northwest of Gavkhuni playa and northwest of the sand dunes in margin of the Zayandehrud river particularly from Varzaneh to the playa. The megafans surrounding the playa can be partly origin of these sediments. The Gavkhuni playa lake is composed of three major flats namely sand, mud and salt flats. The salt flat forms the major part of the playa. Igneous, metamorphic and sedimentary (mainly carbonates rocks outcrop in the drainage basin of the Gavkhuni playa lake. Schist, gneiss, limestone, shale and andesite are the dominant lithology in this basin. The main objective of this research is to determine the concentrations of Cd, Co, Sr, Zn, Ag, Cu, Pb, Mn and Ni in the eolian sand deposits, the factors influencing the distributions of these elements and also relationship between the heavy metals and the minerals (particularly heavy minerals containing these elements. Material & Methods The eolian sands (sand dunes and sand flats of the Gavkhuni playa were sampled in 15 sampling points from north to south of the playa. Grain size distribution of the sediments were determined through dry sieving method. Heavy minerals were separated and studied through microscopy of the prepared thin and polish sections. The concentration

  17. Uncertainty-based calibration and prediction with a stormwater surface accumulation-washoff model based on coverage of sampled Zn, Cu, Pb and Cd field data

    DEFF Research Database (Denmark)

    Lindblom, Erik Ulfson; Ahlman, S.; Mikkelsen, Peter Steen

    2011-01-01

    μg/l ±80% for Pb and 0.6 μg/l ±35% for Cd. This uncertainty-based calibration procedure adequately describes the prediction uncertainty conditioned on the used model and data, but seasonal and site-to-site variation is not considered, i.e. predicting metal concentrations in stormwater runoff from...

  18. Solid phase extraction of Cu(II), Ni(II), Pb(II), Cd(II) and Mn(II) ions with 1-(2-thiazolylazo)-2-naphthol loaded Amberlite XAD-1180.

    Science.gov (United States)

    Tokalioğlu, Serife; Yilmaz, Vedat; Kartal, Senol

    2009-05-01

    A new method for separation and preconcentration of trace amounts of Cu(II), Ni(II), Pb(II), Cd(II) and Mn(II) ions in various matrices was proposed. The method is based on the adsorption and chelation of the metal ions on a column containing Amberlite XAD-1180 resin impregnated with 1-(2-thiazolylazo)-2-naphthol (TAN) reagent prior to their determination by flame atomic absorption spectrometry (FAAS). The effect of pH, type, concentration and volume of eluent, sample volume, flow rates of sample and elution solutions, and interfering ions have been investigated. The optimum pH for simultaneous retention of all the metal ions was 9. Eluent for quantitative elution was 20 ml of 2 mol l(-1) HNO(3). The optimum sample and eluent flow rates were found as 4 ml min(-1), and also sample volume was 500 ml, except for Mn (87% recovery). The sorption capacity of the resin was found to be 0.77, 0.41, 0.57, and 0.30 mg g(-1) for Cu(II), Ni(II), Cd(II), and Mn(II), respectively. The preconcentration factor of the method was 200 for Cu(II), 150 for Pb(II), 100 for Cd(II) and Ni(II), and 50 for Mn(II). The recovery values for all of the metal ions were > or = 95% and relative standard deviations (RSDs) were < or = 5.1%. The detection limit values were in the range of 0.03 and 1.19 microg l(-1). The accuracy of the method was confirmed by analysing the certified reference materials (TMDA 54.4 fortified lake water and GBW 07605 tea samples) and the recovery studies. This procedure was applied to the determination of Cu(II), Ni(II), Pb(II), Cd(II) and Mn(II) in waste water and lake water samples.

  19. Immobilization of heavy metal ions (CuII, CdII, NiII, and PbII) by broiler litter-derived biochars in water and soil.

    Science.gov (United States)

    Uchimiya, Minori; Lima, Isabel M; Thomas Klasson, K; Chang, SeChin; Wartelle, Lynda H; Rodgers, James E

    2010-05-12

    Chars, a form of environmental black carbon resulting from incomplete burning of biomass, can immobilize organic contaminants by both surface adsorption and partitioning mechanisms. The predominance of each sorption mechanism depends upon the proportion of organic to carbonized fractions comprising the sorbent. Information is currently lacking in the effectiveness of char amendment for heavy metal immobilization in contaminated (e.g., urban and arms range) soils where several metal contaminants coexist. The present study employed sorbents of a common biomass origin (broiler litter manure) that underwent various degrees of carbonization (chars formed by pyrolysis at 350 and 700 degrees C and steam-activated analogues) for heavy metal (Cd(II), Cu(II), Ni(II), and Pb(II)) immobilization in water and soil. ATR-FTIR, (1)H NMR, and Boehm titration results suggested that higher pyrolysis temperature and activation lead to the disappearance (e.g., aliphatic -CH(2) and -CH(3)) and the formation (e.g., C-O) of certain surface functional groups, portions of which are leachable. Both in water and in soil, pH increase by the addition of basic char enhanced the immobilization of heavy metals. Heavy metal immobilization resulted in nonstoichiometric release of protons, that is, several orders of magnitude greater total metal concentration immobilized than protons released. The results suggest that with higher carbonized fractions and loading of chars, heavy metal immobilization by cation exchange becomes increasingly outweighed by other controlling factors such as the coordination by pi electrons (C=C) of carbon and precipitation.

  20. The effect of mustard gas on salivary trace metals (Zn, Mn, Cu, Mg, Mo, Sr, Cd, Ca, Pb, Rb.

    Directory of Open Access Journals (Sweden)

    Elham Zamani Pozveh

    Full Text Available We have determined and compared trace metals concentration in saliva taken from chemical warfare injures who were under the exposure of mustard gas and healthy subjects by means of inductively coupled plasma optical emission spectroscopy (ICP-OES for the first time. The influence of preliminary operations on the accuracy of ICP-OES analysis, blood contamination, the number of restored teeth in the mouth, salivary flow rate, and daily variations in trace metals concentration in saliva were also considered. Unstimulated saliva was collected at 10:00-11:00 a.m. from 45 subjects in three equal groups. The first group was composed of 15 healthy subjects (group 1; the second group consisted of 15 subjects who, upon chemical warfare injuries, did not use Salbutamol spray, which they would have normally used on a regular basis (group 2; and the third group contained the same number of patients as the second group, but they had taken their regular medicine (Salbutamol spray; group 3. Our results showed that the concentration of Cu in saliva was significantly increased in the chemical warfare injures compared to healthy subjects, as follows: healthy subjects 15.3± 5.45 (p.p.b., patients (group 2 45.77±13.65, and patients (Salbutamol spray; group 3 29 ±8.51 (P <0.02. In contrast, zinc was significantly decreased in the patients, as follows: healthy subjects 37 ± 9.03 (p.p.b., patients (group 2 12.2 ± 3.56, and patients (Salbutamol spray; group 3 20.6 ±10.01 (P < 0.01. It is important to note that direct dilution of saliva samples with ultrapure nitric acid showed the optimum ICP-OES outputs.

  1. Dissolved and labile concentrations of Cd, Cu, Pb, and Zn in the South Fork Coeur d'Alene River, Idaho: Comparisons among chemical equilibrium models and implications for biotic ligand models

    Science.gov (United States)

    Balistrieri, L.S.; Blank, R.G.

    2008-01-01

    In order to evaluate thermodynamic speciation calculations inherent in biotic ligand models, the speciation of dissolved Cd, Cu, Pb, and Zn in aquatic systems influenced by historical mining activities is examined using equilibrium computer models and the diffusive gradients in thin films (DGT) technique. Several metal/organic-matter complexation models, including WHAM VI, NICA-Donnan, and Stockholm Humic model (SHM), are used in combination with inorganic speciation models to calculate the thermodynamic speciation of dissolved metals and concentrations of metal associated with biotic ligands (e.g., fish gills). Maximum dynamic metal concentrations, determined from total dissolved metal concentrations and thermodynamic speciation calculations, are compared with labile metal concentrations measured by DGT to assess which metal/organic-matter complexation model best describes metal speciation and, thereby, biotic ligand speciation, in the studied systems. Results indicate that the choice of model that defines metal/organic-matter interactions does not affect calculated concentrations of Cd and Zn associated with biotic ligands for geochemical conditions in the study area, whereas concentrations of Cu and Pb associated with biotic ligands depend on whether the speciation calculations use WHAM VI, NICA-Donnan, or SHM. Agreement between labile metal concentrations and dynamic metal concentrations occurs when WHAM VI is used to calculate Cu speciation and SHM is used to calculate Pb speciation. Additional work in systems that contain wide ranges in concentrations of multiple metals should incorporate analytical speciation methods, such as DGT, to constrain the speciation component of biotic ligand models. ?? 2008 Elsevier Ltd.

  2. Adsorption Studies on Aqueous Cd2 +, Pb2+, Cu2 + Ions by Thiol and Humic Acid Functionalized Fe3O4 Nanoparticles%巯基修饰和胡敏酸包裹纳米Fe3O4颗粒的制备及其对溶液中pb2+ Cd2+ Cu2+的吸附效果研究

    Institute of Scientific and Technical Information of China (English)

    王萌; 雷丽萍; 方敦煌; 徐照丽; 陈世宝

    2011-01-01

    采用改进的化学共沉淀法制备纳米Fe3O4颗粒,利用3-巯丙基三乙氧基硅烷(MPTES)和胡敏酸(HA)对所制备的纳米Fe3O4进行巯基修饰和胡敏酸包裹,通过红外光谱(IR)、X射线衍射分析(XRD)等方法对上述制备的纳米颗粒的性质进行了表征,同时对上述不同的纳米Fe3O4颗粒在恒温下对水体中金属离子(Pb2+、Cd2+、Cu2+)的吸附进行了研究.结果表明,所制备的功能化前后的纳米Fe3O4纯度较高,平均粒径约为20~30 nm,且分布均匀.不同纳米型Fe3O4颗粒对溶液中金属离子具有较好的吸附性能,其吸附等温线均可以用Langmuir方程进行较好的拟合;裸露的纳米Fe3O4颗粒对Pb2+最大吸附量(b)达到172.4 mg·g-1,经过胡敏酸包裹后的纳米Fe3O4颗粒对Cd2+、Cu2+的最大吸附量分别增加了75.8%和231.5%;对不同金属离子而言,裸露的和巯基修饰的纳米Fe3O4对3种重金属离子的吸附能力的强弱为pb2+>Cd2+>Cu2+,而经胡敏酸包裹后的顺序则为Pb2+>Cu2,Cd2+;与裸露的和巯基修饰的纳米Fe3O4相比,经HA包裹的纳米Fe3O4对Cd2+和Cu2+具有较高的吸附量和吸附亲和力参数,而对Pb2+的吸附无显著性差异.%The magnetic Fe3O4 nanoparticles were prepared using modified chemical co- precipitation, and corresponding thiolated and coating nanoparticles were also obtained via surface mercaptopropyltriethoxysilane(MPTES) modification and humic acid(HA). The properties and structure of the nanoparticles were characterized by X-Ray diffraction(XRD) and infrared spectroscopy(IR) etc. The application of the nanoparticles to the adsorption of aqueous Pb2+, Cd2+, Cu2+ were also investigated in this study. The results showed that the average size of prepared nanoparticles were about 20-30 nm with homogeneous distribution; the nanoparticles could adsorb Pb2+, Cd2+, Cu2+ in solution efficiently and the adsorption data were well fitted with the Langmuir isotherm. The sorption maxima of

  3. Evaluation of the air quality regarding total suspended particles and heavy metals (Pb, Cd, Ni, Cu, Cr) in the Hermosillo city, Sonora, Mexico, during a yearly period; Evaluacion de la calidad del aire respecto de particulas suspendidas totales y metales pesados (Pb, Cd, Ni, Cu, Cr) en la Ciudad de Hermosillo, Sonora, Mexico, durante un periodo anual

    Energy Technology Data Exchange (ETDEWEB)

    Cruz C, M. E.; Quintero N, M. [Universidad Autonoma de Baja California, Instituto de Ingenieria, Campus Mexicali, Calle de la Normal s/n, y Blvd. Benito Juarez, Col. Insurgentes Este, Mexicali, Baja California (Mexico); Gomez A, A.; Varela S, J., E-mail: martincruzcampas@hotmail.com [Universidad de Sonora, Departamento de Ingenieria Quimica y Metalurgia, Blvd. Rosales y Luis Ensina s/n, Edificio 5B, Col. Centro, 83000 Hermosillo, Sonora (Mexico)

    2013-07-01

    In the present study, the air quality of the city of Hermosillo, Sonora, Mexico was assessed considering total suspended particulates (tsp) and heavy metals (Pb, Cd, Ni, Cu, Cr) from June 2001 through May 2002 in three monitoring sites Centro (Mazon), Nor este (CESUES) and Noroeste (CBTIS). The filter-samples used for that purpose were provided by the Air Quality Evaluation and Improvement Program (PEMCA) of the municipality of Hermosillo. The sampling method was based on high volume sampling frequency set every 6 days with non-simultaneous sampling among the three sampling sites. Filters were dissolved for metal determination by acidic-extraction, and then analyzed by flame atomic absorption spectrophotometry. Results indicate that tsp concentrations at Centro and Noroeste sites were frequently higher than the maximum daily permissible level (260 {mu}g/m{sup 3}), while in the three sites the annual average was higher than the maximum annual permissible level (75 {mu}g/m{sup 3}) both established in the standard NOM-024-Ssa-1993 (Ssa 1994a). According to the Air Quality Standard Index (US EPA 1992a), used in Mexico by Air Quality Metropolitan Index (IMECA) the results indicate that the air quality in the city of Hermosillo regarding tsp was placed between no satisfactory and poor. In regard to heavy metals (Pb, Cd, Ni, Cu, Cr), concentrations detected were below the maximum permissible levels and/or criteria taking into account the standard NOM-026-Ssa-1993 (Ssa 1994b), the Who criterion (2000), the European Union criterion (Cec 2003), and the European Environmental Agency criteria (EEA 2004). Such findings would mean that airborne metals are of no concern; however, air quality is still classified as no satisfactory due to high particulate matter concentrations. Keeping air quality parameters monitoring is recommended in order to get extensive data for use in risk studies of air quality and health (morbidity/mortality), as well as topographic conditions

  4. Simultaneous determination of trace Cd(II), Pb(II) and Cu(II) by differential pulse anodic stripping voltammetry using a reduced graphene oxide-chitosan/poly-l-lysine nanocomposite modified glassy carbon electrode.

    Science.gov (United States)

    Guo, Zhuo; Li, Dong-di; Luo, Xian-Ke; Li, Ya-Hui; Zhao, Qi-Nai; Li, Meng-Meng; Zhao, Yang-Ting; Sun, Tian-Shuai; Ma, Chi

    2017-03-15

    The reduced graphene oxide (RGO) and Chitosan (CS) hybrid matrix RGO-CS were coated onto the glassy carbon electrode (GCE) surface, then, poly-l-lysine films (PLL) were prepared by electropolymerization with cyclic voltammetry (CV) method to prepare RGO-CS/PLL modified glassy carbon electrode (RGO-CS/PLL/GCE) for the simultaneous electrochemical determination of heavy metal ions Cd(II), Pb(II) and Cu(II). Combining the advantageous features of RGO and CS, RGO and CS are used together because the positively charged CS can interact with the negatively changed RGO to prevent their aggregation. Furthermore, CS has many amino groups along its macromolecular chains and possessed strongly reactive with metal ions. Moreover, PLL modified electrodes have good stability, excellent permselectivity, more active sites and strong adherence to electrode surface, which enhanced electrocatalytic activity. The RGO-CS/PLL/GCE was characterized voltammetrically using redox couples (Fe(CN)6(3-/4-)), complemented with electrochemical impedance spectroscopy (EIS). Differential pulse anodic stripping voltammetry (DPASV) has been used for the detection of Cd(II), Pb(II) and Cu(II). The detection limit of RGO-CS/PLL/GCE toward Cd(II), Pb(II) and Cu(II) is 0.01μgL(-1), 0.02μgL(-1) and 0.02μgL(-1), respectively. The electrochemical parameters that exert influence on deposition and stripping of metal ions, such as supporting electrolytes, pH value, deposition potential, and deposition time, were carefully studied.

  5. Square-wave anodic-stripping voltammetric determination of Cd, Pb, and Cu in a hydrofluoric acid solution of siliceous spicules of marine sponges (from the Ligurian Sea, Italy, and the Ross Sea, Antarctica)

    Energy Technology Data Exchange (ETDEWEB)

    Truzzi, C.; Annibaldi, A.; Illuminati, S.; Bassotti, E.; Scarponi, G. [Polytechnic University of Marche, Ancona (Italy). Department of Marine Science

    2008-09-15

    Square-wave anodic-stripping voltammetry (SWASV) was set up and optimized for simultaneous determination of cadmium, lead, and copper in siliceous spicules of marine sponges, directly in the hydrofluoric acid solution ({proportional_to}0.55 mol L{sup -1} HF, pH {proportional_to}1.9). A thin mercury-film electrode (TMFE) plated on to an HF-resistant epoxy-impregnated graphite rotating-disc support was used. The optimum experimental conditions, evaluated also in terms of the signal-to-noise ratio, were as follows: deposition potential -1100 mV vs. Ag/AgCl, KCl 3 mol L{sup -1}, deposition time 3-10 min, electrode rotation 3000 rpm, SW scan from -1100 mV to +100 mV, SW pulse amplitude 25 mV, frequency 100 Hz, {delta}E{sub step} 8 mV, t{sub step} 100 ms, t{sub wait} 60 ms, t{sub delay} 2 ms, t{sub meas} 3 ms. Under these conditions the metal peak potentials were Cd -654{+-}1 mV, Pb -458 {+-} 1 mV, Cu -198{+-}1 mV. The electrochemical behaviour was reversible for Pb, quasi-reversible for Cd, and kinetically controlled (possibly following chemical reaction) for Cu. The linearity of the response with concentration was verified up to {proportional_to}4 {mu}g L{sup -1} for Cd and Pb and {proportional_to}20 {mu}g L{sup -1} for Cu. The detection limits were 5.8 ng L{sup -1}, 3.6 ng L{sup -1}, and 4.3 ng L{sup -1} for Cd, Pb, and Cu, respectively, with t{sub d}=5 min. The method was applied for determination of the metals in spicules of two specimens of marine sponges (Demosponges) from the Portofino natural reserve (Ligurian Sea, Italy, Petrosia ficiformis) and Terra Nova Bay (Ross Sea, Antarctica, Sphaerotylus antarcticus). The metal contents varied from tens of ng g{sup -1} to {proportional_to}1 {mu}g g{sup -1}, depending on the metal considered and with significant differences between the two sponge species. (orig.)

  6. EVALUACIÓN DE LA CALIDAD DEL AIRE RESPECTO DE PARTÍCULAS SUSPENDIDAS TOTALES (PST) Y METALES PESADOS (Pb, Cd, Ni, Cu, Cr) EN LA CIUDAD DE HERMOSILLO, SONORA, MÉXICO, DURANTE UN PERIODO ANUAL

    OpenAIRE

    Martín Eusebio CRUZ CAMPAS; Agustín GÓMEZ ÁLVAREZ; Margarito QUINTERO NÚÑEZ; Jaime VARELA SALAZAR

    2013-01-01

    En el presente estudio se evaluó la calidad del aire para la ciudad de Hermosillo, Sonora, México, respecto de partículas suspendidas totales (PST) y metales pesados (Pb, Cd, Ni, Cu, Cr) durante el período junio de 2001 a mayo de 2002, en los sitios de monitoreo Centro (Mazón), Noreste (CESUES) y Noroeste (CBTIS). Los filtros muestra usados para ese propósito fueron proporcionados por el Programa de Evaluación y Mejoramiento de la Calidad del Aire (PEMCA) del Ayuntamiento de Hermosillo. El mu...

  7. 冶炼厂周围土壤中Cu、Pb、Zn、Cd的形态分布研究%The Formation Distribution of Zn,Cu and Pb and Cd in the Soil Nearby the Smelter

    Institute of Scientific and Technical Information of China (English)

    姜艳; 詹兴旺; 孙丽达; 肖锐敏; 黄兆龙; 黄笃树

    2011-01-01

    Objective: To detect the soil ecology nearby the smelter.Methods: The study selected the wasteland in chicken street of Yunnan province,and analysed the total quantity of Pb,Zn,Cu and Cd by dispelling method,and studied the form distribution Zn,Cu,Pb and Cd in soil through five states Tessier successive extraction method.The results showed that the total concentration of four heavy metal in the soil is higher than that of National index.The main modality of Cu,Pb,Zn and Cd was residualform,and the rate of exchange state is minimum in the soil.Biological activity and migration ability of four kinds of metal was Cd Pb Zn Cu.Conclusions:(1)The soil nearby the smelter was polluted by heavy metal.(2) The study provided the theory basis for soil bioremediation,extraction and recovery in the future.%目的:观察冶炼厂周围土壤的重金属分布情况。方法:本研究选取云南鸡街周围荒地土壤为样品,采用消解法对土壤中的Cu、Pb、Zn、Cd进行总量分析,并运用Tessier连续提取的五态方法研究该区土壤中Cu、Pb、Zn、Cd的形态分布特征,来检测该地区的土壤生态。结果:该冶炼厂周围土壤中四种重金属的总浓度高于国家土壤环境质量指标;形态分析发现Cu、Pb、Zn、Cd的主要形态为残渣态,可交换态所占比例最小;四种重金属的生物活性和迁移能力大小均为Cd〉Pb〉Zn〉Cu。结论:(1)该地区土壤被重金属污染。(2)为该地区土壤修复提供理论依据,重金属的提取和回收提供资料。

  8. A transferable force field for CdS-CdSe-PbS-PbSe solid systems.

    Science.gov (United States)

    Fan, Zhaochuan; Koster, Rik S; Wang, Shuaiwei; Fang, Changming; Yalcin, Anil O; Tichelaar, Frans D; Zandbergen, Henny W; van Huis, Marijn A; Vlugt, Thijs J H

    2014-12-28

    A transferable force field for the PbSe-CdSe solid system using the partially charged rigid ion model has been successfully developed and was used to study the cation exchange in PbSe-CdSe heteronanocrystals [A. O. Yalcin et al., "Atomic resolution monitoring of cation exchange in CdSe-PbSe heteronanocrystals during epitaxial solid-solid-vapor growth," Nano Lett. 14, 3661-3667 (2014)]. In this work, we extend this force field by including another two important binary semiconductors, PbS and CdS, and provide detailed information on the validation of this force field. The parameterization combines Bader charge analysis, empirical fitting, and ab initio energy surface fitting. When compared with experimental data and density functional theory calculations, it is shown that a wide range of physical properties of bulk PbS, PbSe, CdS, CdSe, and their mixed phases can be accurately reproduced using this force field. The choice of functional forms and parameterization strategy is demonstrated to be rational and effective. This transferable force field can be used in various studies on II-VI and IV-VI semiconductor materials consisting of CdS, CdSe, PbS, and PbSe. Here, we demonstrate the applicability of the force field model by molecular dynamics simulations whereby transformations are initiated by cation exchange.

  9. A transferable force field for CdS-CdSe-PbS-PbSe solid systems

    OpenAIRE

    Fan, Zhaochuan; Koster, Rik S.; Wang, Shuaiwei; Fang, Changming; Anil O. Yalcin; Frans D. Tichelaar; Zandbergen, Henny W.; Van Huis, Marijn A.; Vlugt, Thijs J H

    2014-01-01

    A transferable force field for the PbSe-CdSe solid system using the partially charged rigid ion model has been successfully developed and was used to study the cation exchange in PbSe-CdSe heteronanocrystals [A. O. Yalcin et al., "Atomic resolution monitoring of cation exchange in CdSe-PbSe heteronanocrystals during epitaxial solid-solid-vapor growth," Nano Lett. 14, 3661-3667 (2014)]. In this work, we extend this force field by including another two important binary semiconductors, PbS and C...

  10. Trace elements concentrations (Zn, Cu, Pb, Cd, As and Hg in the Mediterranean mussel (Mytilus galloprovincialis and evaluation of mussel quality and possible human health risk from cultivated and wild sites of the southeastern Adriatic Sea, Montenegro

    Directory of Open Access Journals (Sweden)

    Jović Mihajlo

    2011-01-01

    Full Text Available The Mediterranean mussel Mytilus galloprovincialis (L was collected from the fall 2005 to the winter 2009 from the six sites on the Montenegrin coastline. Two wild samples were collected from the open sea coastline, and two cultivated and two wild were from the Boka Kotorska Bay. The mussels soft tissue was analyzed for zinc (Zn, copper (Cu, lead (Pb, cadmium (Cd, arsenic (As and total mercury (Hg. Concentrations of these metals ranged from 135.5-210 for Zn, 6.2-14.5 for Cu, 4.0-11.5 for Pb, 1.7-2.1 for Cd, 5.8-12.4 for As and 0.11-0.51 for Hg, in mg kg-1 dry weight. The metals were found to be present in the samples at different levels, but not in concentrations higher than maximum residual levels prescribed by the European Union (EU and US Food and Drug Administration (USFDA regulations for seafood. This indicates that the consumption of wild or cultivated mussels from the studied area is safe in moderate quantities.

  11. Application of mesoporous SBA-15 silica functionalized with 4-amino-2-mercaptopyrimidine for the adsorption of Cu(II), Zn(II), Cd(II), Ni(II), and Pb(II) from water.

    Science.gov (United States)

    Jorgetto, Alexandre de Oliveira; Pereira, Silvana Pontes; Silva, Rafael Innocenti Vieira da; Saeki, Margarida Juri; Martines, Marco Antonio Utrera; Pedrosa, Valber de Albuquerque; Castro, Gustavo Rocha de

    2015-01-01

    This work reports the sol-gel synthesis of a SBA-15 silica, and its functionalization with 4-amino-2-mercaptopyrimidine to perform adsorption of metal species from aqueous media. The functionalization of the material was confirmed by FTIR and superficial area measurements. The final material was tested through batch experiments to uncover its adsorptive properties towards the adsorption of Cu(II), Cd(II), Zn(II), Pb(II) and Ni(II). Contact time and pH conditions were investigated, and the material presented slow adsorption kinetics, which was best described by the pseudo-second order model. In addition, at pH 5 - 6, the adsorption of the metal ions was favored. Under optimized conditions, the material had its maximum adsorption capacities determined for all metal species studied, and the obtained values were 13.0 µmol g(-1) for Zn(II), 12.3 µmol g(-1) for Cu(II), 3.45 µmol g(-1) for Ni(II), 2.45 µmol g(-1) for Pb(II) and 0.60 µmol g(-1) for Cd(II). The capacity differences between each metal ion were discussed in terms of their ionic radii and Person's soft/hard acids/bases concept.

  12. Bioaccumulation and Distribution of Heavy Metals (Cd, Cu, Fe, Ni, Pb and Zn in the Different Tissues of Chicoreus capucinus Lamarck (Mollusca: Muricidae Collected from Sungai Janggut, Kuala Langat, Malaysia

    Directory of Open Access Journals (Sweden)

    Franklin Edward Berandah

    2010-01-01

    Full Text Available Knowledge on accumulation and distribution of metals in the soft tissues may help us to understand the processes involved in the uptake and excretion of metals in the different parts of molluscs such as Chicoreus capucinus. Chicoreus capucinus was collected from intertidal areas of Sungai Janggut mudflat, Kuala Langat, Selangor and analysed for heavy metals content in the tissues. The capability of the different parts to accumulate heavy metal from the environment was measured by calculating their Biota-Sediment Accumulation Factor (BSAF values. From this preliminary investigation, it was found that the highest concentrations of Cu were found in the caecum (194±24.4 µg/g dw, Cd in digestive gland (32.9±0.000 µg/g dw and Fe in operculum (971±2.50 µg/g dw. For Ni and Pb, high concentrations in shell were observed and Zinc high levels in most of the tissues studied except shell and operculum. On the other hand, highest BSAF values were obtained in caecum for Cu (101.2, Zn (27.4 and Cd (53.1, while highest BSAF values were obtained in shell for Pb (32.6 and Ni (8.88. However, in general, most of the different parts of the gastropod could be suggested as macro concentrator organs, since the BSAF values were greater than 2. More studies should be conducted in the future to determine the potential of C. capucinus as biomonitor.

  13. Determination of trace Cd, Cu, Fe, Pb and Zn in diesel and gasoline by inductively coupled plasma mass spectrometry after sample clean up with hollow fiber solid phase microextraction system

    Energy Technology Data Exchange (ETDEWEB)

    Nomngongo, Philiswa N.; Ngila, J. Catherine, E-mail: jcngila@uj.ac.za

    2014-08-01

    This study reports a simple and efficient method for the determination of trace Cd, Cu, Fe, Pb and Zn in diesel and gasoline samples by inductively coupled plasma mass spectrometry after matrix removal and analyte pre-concentration using hollow fiber-solid phase microextraction (HF–SPME). The optimization of HF-SPME procedure was carried out using two-level full factorial and central composite designs. Four factors (variables), that are, sample solution pH, acceptor phase amount, extraction time and eluent concentration were optimized. Under the optimized experimental conditions, the precision was ≤ 3% (C = 10 μg L{sup −1}, n = 15), limits of detection and quantification ranged from 0.1 to 0.3 μg L{sup −1} and 0.3–0.9 μg L{sup −1}, respectively, and the maximum preconcentration factor was 30. The HF-SPME method was applied for the determination of trace metals in real gasoline and diesel samples. - Highlights: • Hollow fiber solid phase microextraction of metal ions in diesel and gasoline • Use of hollow fiber-supported sol–gel combined with cation exchange resin • Optimization of HF-SPME using multivariate techniques • Determination of Cd, Cu, Fe, Pb and Zn using ICP–MS • Relatively low LOD and LOQ.

  14. Preconcentration of Pb(II), Cr(III), Cu(II), Ni(II) and Cd(II) ions in environmental samples by membrane filtration prior to their flame atomic absorption spectrometric determinations

    Energy Technology Data Exchange (ETDEWEB)

    Divrikli, Umit [Pamukkale University, Faculty of Arts and Science, Department of Chemistry, 20020 Denizli (Turkey)]. E-mail: udivrikli@pamukkale.edu.tr; Kartal, Aslihan Arslan [Pamukkale University, Faculty of Arts and Science, Department of Chemistry, 20020 Denizli (Turkey); Soylak, Mustafa [Erciyes University, Faculty of Arts and Science, Department of Chemistry, 38039 Kayseri (Turkey); Elci, Latif [Pamukkale University, Faculty of Arts and Science, Department of Chemistry, 20020 Denizli (Turkey)

    2007-07-16

    A method for separation-preconcentration of Pb(II), Cr(III), Cu(II), Ni(II) and Cd(II) ions by membrane filtration has been described. The method based on the collection of analyte metal ions on a cellulose nitrate membrane filter and determination of analytes by flame atomic absorption spectrometry (FAAS). The method was optimized for several parameters including of pH, matrix effects and sample volume. The recoveries of analytes were generally in the range of 93-100%. The detection limits by 3 sigma for analyte ions were 0.02 {mu}g L{sup -1} for Pb(II), 0.3 {mu}g L{sup -1} for Cr(III), 3.1 {mu}g L{sup -1} for Cu(II), 7.8 {mu}g L{sup -1} for Ni(II) and 0.9 {mu}g L{sup -1} for Cd(II). The proposed method was applied to the determination of lead, chromium, copper, nickel and cadmium in tap waters and RM 8704 Buffalo River Sediment standard reference material with satisfactory results. The relative standard deviations of the determinations were below 10%.

  15. 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

    Science.gov (United States)

    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.

  16. Concentrative phenomenon of relative content ratios of Cu, Pb and Zn in soils

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    It is discovered that there is the concentrative phenomenon of relative content ratios of Cu, Pb and Zn in soil by studying their parageneous association in soil, meterites and rocks with the relative content ratios. This not only is helpful to understand the trends of Cu, Cd and Zn enriched and dispersed in the evolution course of earth matter, but also provide evidence for geochemical self-organization that there may be in the process of Cu, Pb and Zn translation and distribution.

  17. Concentración de metales pesados (Cu, Ni, Zn, Cd, Pb en la biota y sedimentos de una playa artificial, en la bahía San Jorge 23°S, norte de Chile Heavy metals concentration (Cu, Ni, Zn, Cd, Pb, in biota and sediments of an artificial beach, in San Jorge bay 23°S, northern Chile

    Directory of Open Access Journals (Sweden)

    Gabriel Castro

    2012-07-01

    Full Text Available Se evaluó el contenido de metales pesados (Cu, Ni, Zn, Cd, Pb en la biota y el sedimento de una playa artificial (Paraíso y una playa natural (El Lenguado, ubicadas en la bahía San Jorge, norte de Chile. Los resultados fueron utilizados para comparar ambos sistemas, el grado de cumplimiento de la normativa ambiental nacional e internacional, y el efecto de la construcción de la playa artificial sobre el nivel de contaminación por metales existentes históricamente en esa zona. En cada playa se ubicaron estaciones equidistantes que abarcaron desde el intermareal hasta el submareal de las cuales fueron extraídos los organismos. Se tomaron muestras de sedimento en cada playa y se determinaron las pendientes con el método de Emery. El análisis granulométrico evidenció el predominio de arena media en playa El Lenguado, y arena media y fina en playa Paraíso. El contenido de materia orgánica fue mayor en El Lenguado. En playa Paraíso se determinaron cinco phylum/superclase agrupados en 19 taxa, mientras que en El Lenguado se encontraron cuatro phylum/superclase agrupados en cc taxa. El contenido de metales en sedimentos y en la mayoría de organismos presentó valores mayores en playa Paraíso. Estos resultados, junto a las normas de calidad chilenas y norteamericanas, sugieren un evidente deterioro en la calidad ambiental de playa Paraíso lo que se demostró por un incremento en las concentraciones de estos metales desde su construcción, los que sobrepasan los límites establecidos por ambas normas.It was evaluated the heavy metal content (Cu, Ni, Zn, Cd, Pb in biota and sediment of an artificial beach (Paraíso and a natural beach (El Lenguado, both located in San Jorge bay, northern Chile. The results were used to compare both systems, the degree of fulfillment of national and international environmental regulations, and the effect of the construction of the artificial beach on the level of metal contamination historically existing in

  18. Concentration of Cu, Zn, Cr, Ni, Cd, and Pb in soil, sugarcane leaf and juice: residual effect of sewage sludge and organic compost application.

    Science.gov (United States)

    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.

  19. Diferencias del sexo y de la edad en el contenido de metales pesados (Cd, Cu, Pb y Zn en pelos de lobo ibérico (Canis lupus signatus del Norte de España

    Directory of Open Access Journals (Sweden)

    M Hermoso de Mendoza García

    2011-01-01

    Full Text Available Como consumidor situado en la cumbre de las cadenas alimenticias, el lobo ibérico (Canis lupus signatus puede sufrir fenómenos de bioacumulación de diferentes contaminantes que se encuentran distribuidos en el medio ambiente. Esto permite pensar en su posible empleo para detectar y evaluar los efectos toxicológicos de xenobióticos diversos como los metales pesados en los ecosistemas terrestres, pudiendo por ello llegar a ser considerado como adecuado biomonitor del medio. Sin embargo, debido a su importancia ecológica, los métodos destructivos no son los más adecuados para dicha determinación toxicológica, de modo que las muestras no destructivas cobran gran importancia como herramienta para dicha biomonitorización. En el presente trabajo se ha determinado la influencia del sexo y de la edad en la concentración de Cd, Cu, Pb y Zn en pelo de lobos procedente del noroeste de España. Las muestras de pelo (n = 158 fueron lavadas y tras ser sometidas a una digestión por vía húmeda, las concentraciones de Cd, Cu, Pb y Zn fueron determinadas mediante Voltamperometría de Disolución Anódica. Con respecto a la variable sexo, las concentraciones más altas de todos los metales pesados estudiados se cuantificaron en el pelo de las hembras, coincidiendo con lo observado por otros autores, lo cual puede estar asociado a las diferencias fisiológicas y a los diferentes hábitos nutricionales. No obstante, sólo se observaron diferencias estadísticamente significativas para un nivel de significación 0,05 en el caso del cobre, acumulándose más en las hembras que en los machos. Respecto a la variable edad, no se observó un patrón de acumulación de estos metales bien definido. Las concentraciones de Cd y Zn fueron superiores en los individuos cachorros (< 1 año mientras que las de Cu y Pb resultaron más altas en los jóvenes (entre 1 y 2 años. En todos los casos, los niveles cuantificados pueden ser considerados indicativos de unas

  20. Influence of the application renewal of glutamate and tartrate on Cd, Cu, Pb and Zn distribution between contaminated soil and Paulownia tomentosa in a pilot-scale assisted phytoremediation study.

    Science.gov (United States)

    Doumett, S; Fibbi, D; Azzarello, E; Mancuso, S; Mugnai, S; Petruzzelli, G; Del Bubba, M

    2011-01-01

    The influence of repeated applications of tartrate (TAR) and glutamate (GLU) at 50-mmol kg(-1) of soil on Cd, Cu, Pb, and Zn distribution between a contaminated soil and Paulownia tomentosa was investigated. TAR and GLU were applied by a single or a double dosage, the latter carried out with an interval between the two applications of thirty days. The comparison of the differences in mean amounts of metals accumulated in the whole plant at the end of single and double TAR and GLU application experiments indicated the positive effect of repeated GLU applications on the accumulation of Cu, Pb, and Zn by Paulownia tomentosa as compared to untreated controls. A similar effect was not observed for the TAR treatments. When soil treated with either TAR or GLU was compared with untreated controls, no significant effect on heavy-metal concentrations in the soil solution was observed 30 days after treatment, suggesting the absence of an increase of the long-term leaching risk of heavy metals in aquifers and surface waters due to the ligand application. A cost analysis of the treatment is also reported.

  1. The influence of metal speciation in combustion waste on the efficiency of Cu, Pb, Zn, Cd, Ni and Cr bioleaching in a mixed culture of sulfur-oxidizing and biosurfactant-producing bacteria.

    Science.gov (United States)

    Karwowska, Ewa; Wojtkowska, Małgorzata; Andrzejewska, Dorota

    2015-12-15

    Metal leachability from ash and combustion slag is related to the physico-chemical properties, including their speciation in the waste. Metals speciation is an important factor that influences the efficiency of metal bioleaching from combustion wastes in a mixed culture of acidophilic and biosurfactant-producing bacteria. It was observed that individual metals tended to occur in different fractions, which reflects their susceptibility to bioleaching. Cr and Ni were readily removed from wastes when present with a high fraction bound to carbonates. Cd and Pb where not effectively bioleached when present in high amounts in a fraction bound to organic matter. The best bioleaching results were obtained for power plant slag, which had a high metal content in the exchangeable, bound to carbonates and bound to Fe and Mg oxides fractions- the metal recovery percentage for Zn, Cu and Ni from this waste exceeded 90%.

  2. 原子吸收法连续测定铋及氧化铋中铜铅铁镉镍%Sequential Determination of Cu, Pb, Fe, Cd and Ni in Bismuth and Bismuth Oxide by Atomic Absorption Spectrometry

    Institute of Scientific and Technical Information of China (English)

    张耀春

    2003-01-01

    HNO3分解样品后,直接用火焰原子吸收法测定铋及氧化铋中铜、铅、铁、镉、镍.方法的检出限分别为Cu 0.22 μg/g, Pb 1.5 μg/g, Fe 0.39 μg/g, Cd 0.11 μg/g , Ni 0.34 μg/g.与国标方法进行比较,分析结果基本一致,精密度试验,各元素的RSD(n=6)≤5.2% .

  3. Determinação estrutural de complexos Cd, Cu, Pb e Zn- DTPA: MS, Infravermelho, RMN13C e investigação teórica (DFT)

    OpenAIRE

    Silva, Vanézia Liane da

    2014-01-01

    Metais pesados, como: Pb, Cd, Zn e Cu, têm dificuldade de translocação nas plantas. O fenômeno parece estar ligado à facilidade de complexação com aminoácidos de plantas, produzindo estruturas estáveis com alto impedimento estérico. É conhecido que o ácido ietilenotriaminopentacético (DTPA) é um poliaminocarboxilato com estrutura semelhante a um aminoácido e que suas soluções já vêm sendo empregadas para determinar teores de elementos de transição no solo. Então este ligante foi escolhido com...

  4. Certification of the contents (mass fractions) of Cd, Pb, Se, Cu, Zn, Fe and Mn in wholemeal flour and lyophilized brown bread reference materials. Wholemeal flour - CRM no. 189; brown bread - CRM no. 191

    Energy Technology Data Exchange (ETDEWEB)

    Wagstaffe, P.J.; Griepink, B.; Muntau, H.; Schramel, P.

    1987-01-01

    The report describes the preparation and certification of a wholemeal flour (CRM 189) and a lyophilised brown breas (CRM 191) for their contents (mass fractions) of elements of toxicological and nutritional importance: Cd, Pb, Se, Cu, Zn, Fe and Mn. Indicative values are also given for As, Ca, Cl, Cr, Hg, Mg, Na, Ni, P and K. Details are given of a preliminary intercomparison of methods for these elements in a wholemeal flour sample, homogeneity and stability studies on the two reference materials and the results and evaluation of the certification exercise which involved 21 European Laboratories. Summaries of the certification methods are also presented. The report concludes with a discussion of the most common sources of error in determining the elements of interest and the steps to be taken to control them. With 7 figs., 28 tabs.

  5. Spectroscopic properties of some new azo-azomethine ligands in the presence of Cu2+, Pb2+, Hg2+, Co2+, Ni2+, Cd2+ and Zn2+ and their antioxidant activity

    Science.gov (United States)

    Shaghaghi, Zohreh

    2014-10-01

    Due to their potential applicability as selective receptors in optical sensors, two novel azo Schiff-base derivatives I and II are synthesized and characterized with FT-IR, 1H NMR and elemental analysis techniques. The optical response of azo groups of I and II towards Ni2+, Co2+, Cu2+, Pb2+, Hg2+, Zn2+ and Cd2+ metal ions is studied in DMSO by UV-vis spectroscopy. The absorption spectra of both compounds with cations show marked changes. In solution, azo Schiff-base I produces a cation induced 95 nm blue shift for Cu2+ ion from 555 nm to 460 nm with remarkable color change from red to yellow. Whereas no significant color change is observed upon addition of studied metal cations to the solution of ligand II or other metal ions to the solution of ligand I. Furthermore, Job's plot indicate 1:1 binding-stoichiometry for I with Cu2+ ion and Benesi-Hildebrand plot is used for the determination of its association constant. Therefore receptor I is highly specific for copper ions in DMSO solution. Finally, the study of antioxidant properties of I and II with DPPH method reveals high and significant activities.

  6. Determinación de factores de enriquecimiento y geoacumulación de Cd, Cr, Cu, Ni, Pb, y Zn en suelos de la cuenca alta del río Lerma

    Directory of Open Access Journals (Sweden)

    Pedro del Aguila Juárez

    2005-01-01

    Full Text Available Se determinó el índice degeoacumulación regional (Igeo y el factor deenriquecimiento (EF en suelos irrigados de lacuenca alta del río Lerma, Estado de México.Se colectaron 55 muestras de suelo de cincolocalidades: Tlachaloya, Ixtlahuaca,Atlacomulco, Temascalcingo y Amealco. Laspropiedades químicas analizadas fueron pH,capacidad de intercambio catiónico, arcilla,materia orgánica, concentración de Cr, Cu, Cd,Ni, Zn, y Pb; así como el Igeo y FE. Los suelosse consideraron excelentes para su usoagrícola en cuanto a los valores de pH ymateria orgánica (MO. Las concentraciones demetales pesados se encontraron por debajo delos límites permisibles. De acuerdo con elfactor de enriquecimiento, el Pb se considerócomo un contaminante moderado con unorigen tanto geológico como antropogénico.El índice de geocumulación mostró que el Pby el Ni son los mayores contaminantes del suelo.

  7. Synthesis and characterization of PbO-CdO nanocomposite and its effect on (Bi,Pb)-2223 superconductor

    Science.gov (United States)

    Yahya, Nabil A. A.; Al-Gaashani, R.; Abd-Shukor, R.

    2017-03-01

    A PbO-CdO nanocomposite-added Bi1.6Pb0.4Sr2Ca2Cu3O10 ((Bi,Pb)-2223) superconductor has been prepared. The effect of the PbO-CdO nanocomposite addition on the transport critical current density ( J c) of (Bi,Pb)-2223 superconductor was investigated. The transition temperature ( T c-onset), zero electrical resistance temperature ( T c- R=0), and J c of the samples were measured by the four-probe method. Phase formation, structure, and microstructure of samples were investigated. The distribution of nanoparticle size was determined. The results indicated that the PbO-CdO-added samples showed larger grain size and an increased volume fraction of high- T c phase (Bi-2223) compared to the non-added sample. A slight increase in T c- R=0 of x = 0.15 wt% was observed. J c of the PbO-CdO nanocomposite-added samples was significantly higher than for the non-added sample. That could be explained by the possibility that the PbO-CdO nanocomposite acts as an effective flux pinning center in (Bi,Pb)-2223. At 77 K, J c of x = 0.15 wt% added sample was more than 20 times larger than J c of the non-added sample ( x = 0 wt%). A combined effect of enhanced flux pinning, increased fraction of high- T c phase and improved grain size, which led to increase in the J c of added samples, is discussed.

  8. Impacts of anthropogenic pressures on the water quality of the Gironde Estuary (SW France) from the Urban Agglomeration of Bordeaux: spatial characterization and inputs of trace metal elements (Ag, As, Cd, Cu, Pb and Zn)

    Science.gov (United States)

    Kessaci, Kahina; Coynel, Alexandra; Blanc, Gérard; Deycard, Victoria N.; Derriennic, Hervé; Schäfer, Jörg

    2014-05-01

    Recent European legislation (2000/60/CE) has listed eight trace metal elements as priority toxic substances for water quality. Urban metal inputs into hydrosystems are of increasing interest to both scientists and managers facing restrictive environmental protection policies, population increase and changing metal applications. The Gironde Estuary (SW France; 625 km2) is known for its metal/metalloid pollution originating from industrial (e.g. Cd, Zn, Cu, As, Ag, Hg) or agricultural sources (e.g. Cu) in the main fluvial tributaries (Garonne and Dordogne Rivers). However, little peer-reviewed scientific work has addressed the impact of urban sources on the Gironde Estuary, especially the Urban Agglomeration of Bordeaux (~1 million inhabitants) located on the downstream branch of the Garonne River. In this study, a snapshot sampling campaign was performed in 2011 for characterizing the spatial distribution of dissolved and particulate metal/metalloid (As, Ag, Cd, Pb, Zn, Cu) concentrations in three suburban watersheds: the Jalle of Blanquefort (330 km2), Eau Bourde (140 km2), and Peugue (112 km2). Furthermore, particulate metal Enrichment Factors (EF) were calculated using local geochemical background measured at the bottom of a sediment core (492 cm). Results indicated that metal concentrations displayed a high spatial variability depending on the suburban watershed and the studied element. Local concentrations anomalies were observed for: (i) As in the Eau Bourde River in dissolved (4.2 μg/l) and particulate phases (246 mg/kg; EF= 20) and attributed to a nearby industrial incinerator; (ii) Zn in the Peugue River with maximum dissolved and particulate concentrations of 87 μg/l and 1580 mg/kg (EF=17), respectively, probably due to urban habitation runoff; (iii) Ag in the Jalle of Blanquefort River with high dissolved (74 ng/l) and particulate concentrations (33.7 mg/kg; EF=117) due to industrial activities in the downstream part. Based on hydro

  9. Highly efficient simultaneous ultrasonic-assisted adsorption of Pb(II), Cd(II), Ni(II) and Cu (II) ions from aqueous solutions by graphene oxide modified with 2,2'-dipyridylamine: Central composite design optimization.

    Science.gov (United States)

    Zare-Dorabei, Rouholah; Ferdowsi, Somayeh Moazen; Barzin, Ahmad; Tadjarodi, Azadeh

    2016-09-01

    In present work, a graphene oxide chemically modified with 2,2'-dipyridylamine (GO-DPA), was synthesized by simple, fast and low-cost process for the simultaneous adsorption of four toxic heavy metals, Pb(II), Cd(II), Ni(II) and Cu(II), from aqueous solutions. The synthesized adsorbent was characterized by FT-IR, XRD, XPS, SEM and AFM measurements. The effects of variables such as pH solution, initial ion concentrations, adsorbent dosage and sonicating time were investigated on adsorption efficiency by rotatable central composite design. The optimum conditions, specified as 8mg of adsorbent, 20mgL(-1) of each ion at pH 5 and short time of 4min led to the achievement of a high adsorption capacities. Ultrasonic power had important role in shortening the adsorption time of ions by enhancing the dispersion of adsorbent in solution. The adsorption kinetic studies and equilibrium isotherms for evaluating the mechanism of adsorption process showed a good fit to the pseudo-second order and Langmuir model, respectively. The maximum adsorption capacities (Qm) of this adsorbent were 369.749, 257.201, 180.893 and 358.824mgg(-1) for lead, cadmium, nickel and copper ions, respectively. The removal performance of adsorbent on the real wastewater samples also showed the feasibility of adsorbent for applying in industrial purposes.

  10. Voltammetric determination of Pb, Cd, Zn, Cu and Se in milk and dairy products collected from Iran: An emphasis on permissible limits and risk assessment of exposure to heavy metals.

    Science.gov (United States)

    Shahbazi, Yasser; Ahmadi, Farhad; Fakhari, Farnoosh

    2016-02-01

    This study was carried out to determine the concentrations of some heavy metals in dairy products, collected from five industrial regions in Iran (n = 250 samples) during winter and summer in 2013. The samples were analyzed using the differential pulse anodic and cathodic stripping voltammetry technique. The obtained ranges of mean Pb, Cd, Cu, Zn and Se were as follow: in raw milk 14.0, 1.11, 427, 571, 2.19 μg kg(-1), in pasteurized milk 9.59, 1.0, 378, 447, 1.78 μg kg(-1), in cheese 14.5, 1.25, 428, 586, 1.68 μg kg(-1), in yoghurt 7.54, 0.99, 399, 431, 1.23 μg kg(-1) and in doogh 7.2, 0.84, 320, 369, 0.99 μg kg(-1), respectively. In nearly all cases the concentrations of the metals were below the international permissible limits and do not pose a health concern for the consumption of milk and dairy products in Iran.

  11. Adsorption of Cu(II), Zn(II), Cd(II) and Pb(II) by dead Avena fatua biomass and the effect of these metals on their growth.

    Science.gov (United States)

    Areco, María Mar; Saleh-Medina, Leila; Trinelli, María Alcira; Marco-Brown, Jose Luis; Dos Santos Afonso, María

    2013-10-01

    The biosorption of copper(II), zinc(II), cadmium(II) and lead(II) from aqueous solutions by dead Avena fatua biomass and the effect of these metals on the growth of this wild oat were investigated. Pseudo-first- and second-order and intra-particle diffusion models were applied to describe the kinetic data and to evaluate the rate constants. The adsorption kinetics of all the metals follows a pseudo-second-order model. The adsorption capacity was determined, and the Freundlich and Langmuir models were applied. The experimental data obtained for all the metals are best described by the Langmuir model. A. fatua was characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and zeta potential. The results obtained evidence the presence of Zn(II), Cu(II), Cd(II) or Pb(II) on the surface of the weed. The growth of A. fatua was affected by the presence of all metals. The decrease in the growth rate with increasing metal concentration was more noticeable for zinc.

  12. Solid-phase extraction of Mn(II), Co(II), Ni(II), Cu(II), Cd(II) and Pb(II) ions from environmental samples by flame atomic absorption spectrometry (FAAS)

    Energy Technology Data Exchange (ETDEWEB)

    Duran, Celal [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Gundogdu, Ali [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Bulut, Volkan Numan [Department of Chemistry, Giresun Faculty of Art and Science, Karadeniz Technical University, 28049 Giresun (Turkey); Soylak, Mustafa [Department of Chemistry, Faculty of Art and Science, Erciyes University, 38039 Kayseri (Turkey)]. E-mail: soylak@erciyes.edu.tr; Elci, Latif [Department of Chemistry, Faculty of Art and Science, Pamukkale University, 20020 Denizli (Turkey); Sentuerk, Hasan Basri [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Tuefekci, Mehmet [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey)

    2007-07-19

    A new method using a column packed with Amberlite XAD-2010 resin as a solid-phase extractant has been developed for the multi-element preconcentration of Mn(II), Co(II), Ni(II), Cu(II), Cd(II), and Pb(II) ions based on their complex formation with the sodium diethyldithiocarbamate (Na-DDTC) prior to flame atomic absorption spectrometric (FAAS) determinations. Metal complexes sorbed on the resin were eluted by 1 mol L{sup -1} HNO{sub 3} in acetone. Effects of the analytical conditions over the preconcentration yields of the metal ions, such as pH, quantity of Na-DDTC, eluent type, sample volume and flow rate, foreign ions etc. have been investigated. The limits of detection (LOD) of the analytes were found in the range 0.08-0.26 {mu}g L{sup -1}. The method was validated by analyzing three certified reference materials. The method has been applied for the determination of trace elements in some environmental samples.

  13. Chitosan film loaded with silver nanoparticles-sorbent for solid phase extraction of Al(III), Cd(II), Cu(II), Co(II), Fe(III), Ni(II), Pb(II) and Zn(II).

    Science.gov (United States)

    Djerahov, Lubomir; Vasileva, Penka; Karadjova, Irina; Kurakalva, Rama Mohan; Aradhi, Keshav Krishna

    2016-08-20

    The present study describes the ecofriendly method for the preparation of chitosan film loaded with silver nanoparticles (CS-AgNPs) and application of this film as efficient sorbent for separation and enrichment of Al(III), Cd(II), Cu(II), Co(II), Fe(III), Ni(II), Pb(II) and Zn(II). The stable CS-AgNPs colloid was prepared by dispersing the AgNPs sol in chitosan solution at appropriate ratio and further used to obtain a cast film with very good stability under storage and good mechanical strength for easy handling in aqueous medium. The incorporation of AgNPs in the structure of CS film and interaction between the polymer matrix and nanoparticles were confirmed by UV-vis and FTIR spectroscopy. The homogeneously embedded AgNPs (average diameter 29nm, TEM analysis) were clearly observed throughout the film by SEM. The CS-AgNPs nanocomposite film shows high sorption activity toward trace metals under optimized chemical conditions. The results suggest that the CS-AgNPs nanocomposite film can be feasibly used as a novel sorbent material for solid-phase extraction of metal pollutants from surface waters.

  14. Evaluation de la contamination de la chaîne trophique par les éléments traces (Cu, Co, Zn, Pb, Cd, U, V et As dans le bassin de la Lufira supérieure (Katanga/RD Congo

    Directory of Open Access Journals (Sweden)

    Katemo Manda, B.

    2010-01-01

    Full Text Available Evaluation of Contamination of the Food Chain by Trace Elements (Cu, Co, Zn, Pb, Cd, U, V and As in the Basin of the Upper Lufira (Katanga/DR Congo. Seven trace elements (Cu, Co, Zn, Cd, Pb, U, V and As were analyzed using a HR ICP-MS in samples of water, plankton, leaves of Phragmites australis, muscle and gills of three fish species (Oreochromis macrochir, Tilapia rendalli, Clarias gariepinus collected in the basin of the upper Lufira. The results indicate a high copper (70.9 ppm and cobalt (32.3 ppm content in the effluent of complex hydrometallurgical Shituru. If contamination of rivers decreases with distance from the pollution source, the values are very high in lake Tshangalele for plankton and leaves of P. australis. For fish, the results indicate that Pb, U, V, Cu, Co and Cd accumulates preferentially in the gills but Zn accumulates more in the muscles. As accumulates in the same order of magnitude in both organs. These results confirm the pollution of the basin by the effluents from Lufira complex hydrometallurgical Shituru.

  15. Metal (Pb, Cd, and Cu)-induced reactive oxygen species accumulations in aerial root cells of the Chinese banyan (Ficus microcarpa).

    Science.gov (United States)

    Liu, Nan; Lin, Zhifang; Mo, Hui

    2012-10-01

    The current study evaluated the toxicity of three heavy metals to aerial roots of the Chinese banyan (Ficus microcarpa), which is a tree species native to China. In a laboratory experiment, segments of aerial roots cut from trees were treated with 0, 25, 50, 100, and 200 μM of lead, cadmium, or copper (Cu). The contents of these heavy metals in cells increased and root cell viability decreased with increases in treatment concentration. High levels of reactive oxygen species accumulated in the aerial root sections after heavy metal treatment. Both biochemical assay and histochemical localization showed that O(2) (•-), which is a precursor of H(2)O(2) accumulated in root sections and that the amount accumulated was positively related to heavy metal concentration, especially for Cu-treated samples. Histochemical staining with diaminobenzidine (DAB) and a fluorometric scopoletin oxidation assay indicated that the amount of H(2)O(2) accumulated was positively related to heavy metal concentration in the treatments; the scopoletin fluorescence assay was more sensitive and efficient than DAB staining for detection and quantification of H(2)O(2). The results indicate that aerial roots are sensitive to heavy metal-induced oxidative damage and that aerial roots have the potential to be used as indicators of heavy metal pollution in urban areas.

  16. Use of polymer-bound Schiff base as a new liquid binding agent of diffusive gradients in thin-films for the measurement of labile Cu²⁺, Cd²⁺ and Pb²⁺.

    Science.gov (United States)

    Fan, Hong-Tao; Liu, Jin-Xiu; Sui, Dian-Peng; Yao, Hui; Yan, Feng; Sun, Ting

    2013-09-15

    A new diffusive gradients in thin-films (DGT) device with solution of polymer-bound Schiff base (Py-PEI) derived from poly(ethyleneimine) and 2-pyridinecarboxaldehyde as the binding agent (Py-PEI DGT) was developed for measuring labile Cu(2+), Cd(2+) and Pb(2+) in waters. In synthetic solution, uptake percentages of Cu(2+), Cd(2+) and Pb(2+) by Py-PEI DGT were 99.2 ± 4.4%, 103.7 ± 4.8% and 98.7 ± 5.5% of the total metals, respectively. Performance of Py-PEI DGT was independent of pH 4-8.5 and ionic strength 1 × 10(-4)-0.1 mol L(-1). The uptake of labile metals showed agreement with the theoretical values of free ions in EDTA solution, and decreased with increase of humic acid (HA) and dissolved organic carbon (DOC) contents in water due to the complexation of HA and DOC with metals. DGT devices containing different liquid binding agents (Py-PEI, polyacrylate (PA) and poly(4-styrenesulfonate) (PSS)) were deployed in the same solution. The higher uptake percentages of Py-PEI DGT (13.2 ± 1.1, 26.5 ± 2.4 and 62.7 ± 3.2% of total Cu(2+), Cd(2+) and Pb(2+)) were obtained with respective to PSS DGT (6.7 ± 0.6, 9.2 ± 0.9 and 29.6 ± 2.7% of total above metals) and PA DGT (8.9 ± 0.9 and 16.2 ± 1.1% of total Cu(2+) and Cd(2+)) due to its relatively strong binding affinity with metals.

  17. Determination of Five Heavy Metals (Cu, Pb, As, Cd, Hg) in Folium Microcotis by Microwave Digestion with Inductively Coupled Plasma Mass Spectrometry%微波消解/ICP-MS法测定布渣叶中5种重金属的含量

    Institute of Scientific and Technical Information of China (English)

    卢鹏; 陈浩桉; 隆颖; 杨立伟; 叶文才; 江仁望

    2011-01-01

    Objective To assay the contents of 5 heavy metals of copper(Cu) , arsenic 1 (As) , cadmium(Cd), hydrargyrum (Hg), plumbum (Pb) in Folium Microcotis by microwave digestion with inductively coupled plasma mass spectrometry(ICP-MS). Methods With germanium(72Ge) , indium(115In) and bismuth(209Bi) as the internal standard substance, the contents of the 5 heavy metals of Cu, Pb, Hg, As and Cd were detected with ICP-MS simultaneously after the samples of Folium Microcotis was treated by microwave digestion. The national standard substance of orange leaves(GBW10020) was used to estimate the accuracy of method. Results For all of the analyzed heavy metals, the correlation coefficient of the calibration curves was over 0.9990, RSD were in the range of 1.1 %~11.6 %, and the recovery rates of the procedure were 97.9 %~108.9 %. Conclusion This method is accurate, convenient, and rapid with high sensitivity, and can be applied to assay the five heavy metals of Cu, Cd, Hg, Pb, As in Folium Microcotis.%目的 采用微波消解电感耦合等离子体质谱(ICP- MS)法测定布渣叶药材中铜(Cu)、铅(Pb)、汞(Hg)、砷(As)、镉(Cd)五种重金属的含量.方法布渣叶经微波消解后,以锗(72Ge)、铟(115In)、铋(209Bi)作为内标物质,用ICP- MS法同时测定样品中Cu、Pb、Hg、As、Cd五种重金属元素的含量.用国家一级标准物质柑橘叶(GBW 10020)评价方法的准确性.结果对于所测元素,校准曲线相关系数r>0.9990回收率为97.9%~108.9%,RSD值在1.1%~11.6%.结论该方法简便、快速、灵敏度高,适合于布渣叶中五种重金属的含量测定.

  18. Distribution of P, K, Ca, Mg, Cd, Cu, Fe, Mn, Pb and Zn in wood and bark age classes of willows and poplars used for phytoextraction on soils contaminated by risk elements.

    Science.gov (United States)

    Zárubová, Pavla; Hejcman, Michal; Vondráčková, Stanislava; Mrnka, Libor; Száková, Jiřina; Tlustoš, Pavel

    2015-12-01

    Fast-growing clones of Salix and Populus have been studied for remediation of soils contaminated by risk elements (RE) using short-rotation coppice plantations. Our aim was to assess biomass yield and distributions of elements in wood and bark of highly productive willow (S1--[Salix schwerinii × Salix viminalis] × S. viminalis, S2--Salix × smithiana clone S-218) and poplar (P1--Populus maximowiczii × Populus nigra, P2--P. nigra) clones with respect to aging. The field experiment was established in April 2008 on moderately Cd-, Pb- and Zn- contaminated soil. Shoots were harvested after four seasons (February 2012) and separated into annual classes of wood and bark. All tested clones grew on contaminated soils, with highest biomass production and lowest mortality exhibited by P1 and S2. Concentrations of elements, with exception of Ca and Pb, decreased with age and were higher in bark than in wood. The Salix clones were characterised by higher removal of Cd, Mn and Zn compared to the Populus clones. Despite generally higher RE content in young shoots, partly due to lower wood/bark ratios and higher RE concentrations in bark, the overall removal of RE was higher in older wood classes due to higher biomass yield. Thus, longer rotations seem to be more effective when phytoextraction strategy is considered. Of the four selected clones, S1 exhibited the best removal of Cd and Zn and is a good candidate for phytoextraction.

  19. Molecular Dynamics study of Pb overlayer on Cu(100)

    Science.gov (United States)

    Karimi, M.; Tibbits, P.; Ila, D.; Dalins, I.; Vidali, G.

    1991-01-01

    Isothermal-isobaric Molecular Dynamics (MD) simulation of a submonolayer Pb film in c(2x2) ordered structure adsorbed on a Cu(100) substrate showed retention of order to high T. The Embedded Atom Method (EAM) calculated the energy of atoms of overlayer and substrate. The time-averaged squared modulus of the two dimensional structure factor for the Pb overlayer measured the order of the overlayer. The results are for increasing T only, and require verification by simulated cooling.

  20. Cumulation of Cu, Zn, Cd, and Mn in Plants of Gardno Lake

    Directory of Open Access Journals (Sweden)

    Trojanowski J.

    2013-04-01

    Full Text Available In the present paper there have been shown the results of research on yhe content of Zn, Cd, Cu, Mn and Pb in chosen plants of Lake Gardno.The biggest concentration of those metals has been observed in Potamogton natans and Elodea canadensis, on average Zn – 34.9, Pb -2.77, Cd – 0.62, Cu – 3.24 and Mn – 257.4 μg g-1. It has been found that the over-ground parts of the plants under analysis cumulate several times less of heavy metals than their roots. The determined enrichment factors enabled the researchers to state that Cu in the examined plants is of natural origin while Mn, Cd and Zn – of anthropogenic origin.

  1. Separation and preconcentration of Cd(II), Cu(II), Ni(II), and Pb(II) in water and food samples using Amberlite XAD-2 functionalized with 3-(2-nitrophenyl)-1H-1,2,4-triazole-5(4H)-thione and determination by inductively coupled plasma-atomic emission spectrometry.

    Science.gov (United States)

    Kumar, Bommana Naresh; Ramana, D K Venkata; Harinath, Yapati; Seshaiah, Kalluru; Wang, M C

    2011-10-26

    A separation and preconcentration procedure was developed for the determination of trace amounts of Cd(II), Cu(II), Ni(II), and Pb(II) in water and food samples using Amberlite XAD-2 fuctionalized with a new chelating ligand, 3-(2-nitrophenyl)-1H-1,2,4-triazole-5(4H)-thione (Amberlite XAD-2-NPTT). The chelating resin was characterized by Fourier transform infrared spectroscopy (FT-IR) and used as a solid sorbent for enrichment of analytes from samples. The sorbed elements were subsequently eluted with 10 mL of 1.0 M HNO(3), and the eluates were analyzed by inductively coupled plasma-atomic emission spectrometry. The influences of the analytical parameters including pH, amount of adsorbent, eluent type and volume, flow rate of the sample solution, volume of the sample solution, and effect of matrix on the preconcentration of metal ions have been studied. The optimum pH for the sorption of four metal ions was about 6.0. The limits of detection were found to be 0.22, 0.18, 0.20, and 0.16 μg L(-1) for Cd(II), Cu(II), Ni(II), and Pb(II), respectively, with a preconcentration factor 60. The proposed method was applied successfully for the determination of metal ions in water and food samples.

  2. Photovoltaic properties of sintered CdS/CdTe solar cells doped with Cu

    Science.gov (United States)

    Park, J. W.; Ahn, B. T.; Im, H. B.; Kim, C. S.

    1992-11-01

    The effect of Cu doping before sintering on the photovoltaic properties of sintered CdS/CdTe solar cells were investigated by putting various amounts of CuCl2 either into the CdTe layer or into the back contact carbon layer. It was found that, as the amount of CuCl2 in the CdTe layers increased up to 25 ppm, the cell parameters of the sintered CdS/CdTe solar cells remained at about the same values, and then decreased sharply with further increase of CuCl2. The decreases in cell parameters are caused mainly by the increase in the resistivity of CdS and CdTe layer and the decrease in the optical transmission of CdS due to Cu doping from the CdTe.

  3. Improved photovoltaic performance of CdSe/CdS/PbS quantum dot sensitized ZnO nanorod array solar cell

    Science.gov (United States)

    Justin Raj, C.; Karthick, S. N.; Park, Songyi; Hemalatha, K. V.; Kim, Soo-Kyoung; Prabakar, K.; Kim, Hee-Je

    2014-02-01

    Single crystalline zinc oxide (ZnO) nanorod array has been used for the fabrication of CdSe/CdS/PbS/ZnO quantum dot sensitized solar cell (QDSSC). The ZnO nanorod array photoanodes are sensitized with consecutive layer of PbS, CdS and CdSe quantum dots by employing simple successive ion layer adsorption and reaction (SILAR) and chemical bath deposition (CBD) techniques. The performances of the QDSSCs are examined in detail using polysulfide electrolyte with copper sulfide (CuS) counter electrode. The combination of two successive layers of PbS with CdSe/CdS/ZnO shows an improved short circuit current density (12.223 mA cm-2) with a maximum power to conversion efficiency of 2.352% under 1 sun illumination. This enhancement is mainly attributed due to the better light harvesting ability of the PbS quantum dots and make large accumulation of photo-injected electrons in the conduction band of ZnO, and CdSe/CdS layers lower the recombination of photo-injected electrons with the electrolyte, these are well evidenced with the photovoltaic studies and electrochemical impedance spectroscopy.

  4. Biosorption of Cu(Ⅱ) and Pb(Ⅱ) by Auricularia polytricha

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dan; GAO Jianwei; GAO Tingyan; YING Yigao; CHEN Hong

    2007-01-01

    For searching biological material for heavy metal removal of waste-water, using macrofungus Auricularia polytricha as biosorbent for Cu2+ and Pb2+ removal was investigated. After shaking and biosorbing Cu2+ and Pb2+ in solution by biosorbents, the filtrates were tested by AAS and the adsorbed quantity of Cu2+ and Pb2+ was calculated. The biosorbents were effective in removal of Cu2+ and Pb2+ on the biosorbents that showed a highest value around pH 5-6. The biosorption rate of Cu2+ and Pb2+on A. polytricha biomass decreased with increasing the initial concentration of Cu2+ and Pb2+ in the medium. The biosorption of Cu2+ and Pb2+ on the biomasses follows pseudo-second order kinetics. The determined maximum biosorption capacities presented by the fungus biomass were 3.34 and 13.03 mg·g -1 dry weight for Cu2+ and Pb2+, respectively by the biosorption equilibrium with Langmuir adsorption isotherm. According to the whole data analysis in each experiment of studying Cu2+ and Pb2+ biosorption including condition factors and adsorption isotherm, the adsorbed capacity of Pb2+ by A. polytricha biomass was bigger than Cu2+. The biosorption by A. polytricha was most effective when pH 5-6. The biosorbents are suitable for low Cu2+ and Pb2+ concentration waste-water, especially for Pb2+ removal.

  5. Cu-Doped-CdS/In-Doped-CdS Cosensitized Quantum Dot Solar Cells

    Directory of Open Access Journals (Sweden)

    Lin Li

    2014-01-01

    Full Text Available Cu-doped-CdS and In-doped-CdS cosensitized (Cu-doped-CdS/In-doped-CdS quantum dot solar cells (QDSCs are introduced here. Different cosensitized sequences, doping ratios, and the thickness (SILAR cycles of Cu-doped-CdS and In-doped-CdS are discussed. Compared with undoped CdS QDSCs, the short circuit current density, UV-Vis absorption spectra, IPCE (monochromatic incident photon-to-electron conversion, open circuit voltage, and so on are all improved. The photoelectric conversion efficiency has obviously improved from 0.71% to 1.28%.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Photoluminescence of Cu-doped CdTe and related stability issues in CdS/CdTe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Grecu, D. [University of Toledo, Toledo, Ohio 43606-3390 (United States); Compaan, A. D. [University of Toledo, Toledo, Ohio 43606-3390 (United States); Young, D. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Jayamaha, U. [First Solar LLC., Perrysburg, Ohio 43551 (United States); Rose, D. H. [First Solar LLC., Perrysburg, Ohio 43551 (United States)

    2000-09-01

    We explore Cu electronic states in CdTe using photoluminescence as the main investigative method. Our results are consistent with some Cu atoms occupying substitutional positions on the Cd sublattice and with others forming Frenkel pairs of the type Cu{sub i}{sup +}-V{sub Cd}{sup -} involving an interstitial Cu and a Cd vacancy. In addition, we find that Cu-doped CdTe samples exhibit a significant ''aging'' behavior, attributable to the instability of Cu acceptor states as verified by our Hall measurements. The aging appears to be reversible by a 150-200 degree sign C anneal. Our results are used to explain efficiency degradation of some CdTe solar-cell devices which use Cu for the formation of a backcontact. (c) 2000 American Institute of Physics.

  8. On the concentration and separation of the trace-elements fe, cu, zn, mn, pb, mo and co : Paper chromatography

    NARCIS (Netherlands)

    Erkelens, P.C. van

    1961-01-01

    Paper chromatographic separations are described by which the minor constituents of biological ashes are separated either into: (Pb) - Mn - Co - (Pb) - Cu - Fe, Mo, Zn; or into: Cu, Mn, Co - Pb - Fe - Mo - Zn.

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

    Science.gov (United States)

    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.

  10. Biosorption of Cu(II), Zn(II), Cd(II) and Pb(II) by dead biomasses of green alga Ulva lactuca and the development of a sustainable matrix for adsorption implementation.

    Science.gov (United States)

    Areco, María Mar; Hanela, Sergio; Duran, Jorge; Afonso, María dos Santos

    2012-04-30

    Many industries have high heavy metals concentrations in their effluents that should be treated before disposal in drains or natural watercourses. When adsorption process is evaluated to generate and implement an efficient, economical and sustainable method suitable for heavy metals removal from contaminated effluents, it is necessary to develop an experimental setup that contains the adsorbent. Ulva lactuca, a marine green alga, was studied as a natural biosorbent for heavy metals at acid pH conditions. Adsorption experiments were carried out in glass columns and in batch where the alga was suspended or fixed in an agar matrix. Langmuir and Freundlich models were applied to the experimental results. Langmuir model best describes the adsorption isotherms in all analyzed cases. The adsorption capacity increases with pH. Kinetic studies demonstrate that, in most studied cases, the adsorption follows a pseudo second order kinetics model. Removal efficiencies of the biomaterial supported in agar or fixed in columns were: fixed in columns>suspended in batch mode>fixed in agar. Finally, the effect of the presence of two sorbates, Cd and Pb, in the solution was measured and results demonstrate that adsorption of both metals are diminished by co/adsorption.

  11. Study on the relationship between speciation of heavy metals and their ecotoxicity. I. Toxicity of Cu, Cd, Pb and Zn in seawater to three marine algae in the presence of different complexation agents

    Science.gov (United States)

    Zhang, Manping; Wang, Juying; Bao, Junbo

    1992-09-01

    Heavy metal is a main pollutant in the marine ecosystem, so study on the effect of heavy metal on phytoplankton is important. Algae ( Chaetoceros sp., Dunaliella sp., Dicrateria zhanjiangenis Hu. var. sp.) were laboratory cultured to observe the effect of heavy metals on their growth. The effect of different metal ion concentration, the detoxication effect of complexation agents and the growth of algae in different media and different nutrition levels were studied to evaluate the effect of metal speciation. It is proved that trace amount of heavy metals can stimulate the growth of algae cells but that high concentration is lethal. The sequence of toxicity is Cd2+>Zn2+>Pb2+. In ordinary nutrition conditions, the detoxication sequence of complexation agents to Chaetoceros sp. is EDTA >sodium salicylate>sodium oxalate >sodium citrate>sulfanilic acid>O-phenanthroline. This is in good conformity with the stability constant sequence of these agents with copper and good evidence that toxicity of metal ion is related to its activity and not to its total concentration.

  12. (Pb,Cd)-O covalency in PbTiO3-CdTiO3 with enhanced negative thermal expansion.

    Science.gov (United States)

    Wang, Fangfang; Xie, Ying; Chen, Jun; Fu, Honggang; Xing, Xianran

    2014-03-21

    Recently experiments have found that negative thermal expansion is a common phenomenon in PbTiO3-based materials, and their negative thermal expansion is affected by various substitutions. Interestingly, Cd substitution in PbTiO3 has a unique effect in enhancing negative thermal expansion compared with any other A-site substitutions. Therefore, studying Cd substitution in PbTiO3, the role of which still remains unclear, would bring us deeper understanding on the nature of the negative thermal expansion of PbTiO3-based materials. Structure calculations, density of states, Bader analysis and the minimum electron density of Pb1-xCdxTiO3 supercells have been reported on the chemical bond through first-principles calculations here. We found that the hybridization between (Pb,Cd)-O orbitals exists in tetragonal phase. Furthermore, the hybridization between Cd-O orbitals is stronger than that between Pb-O orbitals, and Cd-O covalency promotes the average A-site hybridization. Simultaneously, the average bulk coefficient of thermal expansion is negative and inversely proportional to the Cd substitution amount. So, (Pb,Cd)-O covalency in the tetragonal Pb1-xCdxTiO3 is responsible for the nature of enhanced negative thermal expansion in accordance with our previous experimental investigations.

  13. Synthesis of BiPbSrCaCuO superconductor

    Science.gov (United States)

    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.

  14. Photoluminescence study of Cu diffusion in CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Grecu, D.; Compaan, A.D. [Department of Physics, University of Toledo, Toledo, Ohio (United States)

    1999-03-01

    We report changes in the photoluminescence spectra associated with the diffusion of Cu in CdTe thin films used in CdTe/CdS solar cells. Films grown by vapor transport deposition and radio-frequency sputtering as well as single crystal CdTe were included in the study. The main effects of Cu diffusion appear to be the quenching of a donor-acceptor transition associated with Cd vacancies and the increase in intensity of a lower energy broad-band transition. The PL is subsequently used to explore the effects of electric fields on Cu diffusion. The role of Te as a diffusion barrier for Cu is investigated. {copyright} {ital 1999 American Institute of Physics.}

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

    Energy Technology Data Exchange (ETDEWEB)

    Cook, C.M.; Lanaras, T.; Sgardelis, S.P.; Pantis, J.D. (Univ. of Thessaloniki (Greece))

    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.

  16. Photoluminescence studies of CdS and CdS:Cu

    Science.gov (United States)

    Price, K. J.

    2000-03-01

    Copper plays an important role in CdS/CdTe heterojunction solar cells, both as a dopant and a back contact to the CdTe. However, Cu is also thought to be responsible for the unstable performance of some types of CdS/CdTe devices under extreme conditions. Recently, Cu has been shown to diffuse from the back contact of the CdTe all the way to the CdS/CdTe interface and into the CdS. We have used photoluminescence (PL) to examine the electrically active states of CdS and CdS:Cu single crystals and polycrystalline films. In undoped films, we detect an exitonic feature at 2.54 eV related to a Cd vacancy. This feature is dramatically reduced in Cu-doped samples, indicating Cu in the Cd vacancy site. In addition, we will present results of light-soaking at 1 sun on the stability of the photoluminescence spectra.

  17. Cu-Related Recombination in CdS/CdTe Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Demtsu, S. H.; Albin, D. S.; Sites, J. R.; Metzger, W. K.; Duda, A.

    2008-02-01

    Cu used in the back contact of CdS/CdTe solar cells is known to improve contact behavior and open-circuit voltage. A study of devices made with varying Cu amounts confirmed these observations. However, Cu was also found to be deleterious to current collection. Time-resolved photoluminescence measurements of CdTe devices show that carrier lifetime decreased with increased Cu concentration. Drive-level-capacitance-profiling and low-temperature photoluminescence suggest this decrease in lifetime was associated with increased recombination center density introduced by Cu in the CdTe layer. The resulting impact of increased Cu on device performance was a voltage-dependent collection of photogenerated carriers that reduced fill-factor.

  18. Analysis of CdS/CdTe devices incorporating a ZnTe:Cu/Ti Contact

    Energy Technology Data Exchange (ETDEWEB)

    Gessert, T.A. [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, Colorado 80401 (United States)]. E-mail: tim_gessert@nrel.gov; Asher, S. [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, Colorado 80401 (United States); Johnston, S. [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, Colorado 80401 (United States); Young, M. [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, Colorado 80401 (United States); Dippo, P. [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, Colorado 80401 (United States); Corwine, C. [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, Colorado 80401 (United States)

    2007-05-31

    High-performance CdS/CdTe photovoltaic devices can be produced using a ZnTe:Cu/Ti back contact deposited onto the CdTe layer. We observe that prolonged exposure of the ZnTe:Cu and Ti sputtering targets to an oxygen-containing plasma significantly reduces device open-circuit voltage and fill factor. High-resolution compositional analysis of these devices reveals that Cu concentration in the CdTe and CdS layers is lower for devices with poor performance. Capacitance-voltage analysis and related numerical simulations indicate that the net acceptor concentration in the CdTe is also lower for devices with poor performance. Photoluminescence analyses of the junction region reveal that the intensity of a luminescent peak associated with a defect complex involving interstitial Cu (Cu{sub i}) and oxygen on Te (O{sub Te}) is reduced in devices with poor performance. Combined with thermodynamic considerations, these results suggest that oxygen incorporation into the ZnTe:Cu sputtering target reduces the ability of sputtered ZnTe:Cu film to diffuse Cu into the CdTe.

  19. Electrical Characterization of Cu Composition Effects in CdS/CdTe Thin-Film Solar Cells with a ZnTe:Cu Back Contact: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Li, J. V.; Duenow, J. N.; Kuciauskas, D.; Kanevce, A.; Dhere, R. G.; Young, M. R.; Levi, D. H.

    2012-07-01

    We study the effects of Cu composition on the CdTe/ZnTe:Cu back contact and the bulk CdTe. For the back contact, its potential barrier decreases with Cu concentration while its saturation current density increases. For the bulk CdTe, the hole density increases with Cu concentration. We identify a Cu-related deep level at {approx}0.55 eV whose concentration is significant when the Cu concentration is high. The device performance, which initially increases with Cu concentration then decreases, reflects the interplay between the positive influences and negative influences (increasing deep levels in CdTe) of Cu.

  20. Effect of Cd,Pb Stress on the Activated Oxygen Scavenging System in Tobacco Levves

    Institute of Scientific and Technical Information of China (English)

    严重玲; 洪业汤; 等

    1998-01-01

    The effect of Cd,Pb stress on the activated oxygen scavenging system indicates that the content of chlorophyll.chlorophyll a/b ratio and the activity of CAT gradually decrease,the activity of SOD increases first and then decreases,and the activity of POd Gradually in creases with incrasing concentrations of Cd and Pb,Between Cd and Pb there is synergism in the Activated oxygen scavenging system.The results show that the stress of Cd and Pb can affect the scavenging system of activated oxygen and result in imbalance of activated oxygen metabolism.

  1. Superconducting spin-valve effect and triplet superconductivity in Co Ox/Fe1/Cu /Fe2/Cu /Pb multilayer

    Science.gov (United States)

    Leksin, P. V.; Garif'yanov, N. N.; Kamashev, A. A.; Fominov, Ya. V.; Schumann, J.; Hess, C.; Kataev, V.; Büchner, B.; Garifullin, I. A.

    2015-06-01

    We report magnetic and superconducting properties of the modified spin-valve system CoOx/Fe1/Cu /Fe2/Cu /Pb . Introduction of a Cu interlayer between Fe2 and Pb layers prevents material interdiffusion process, increases the Fe2/Pb interface transparency, stabilizes and enhances properties of the system. This allowed us to perform a comprehensive study of such heterostructures and to present theoretical description of the superconducting spin-valve effect and of the manifestation of the long-range triplet component of the superconducting condensate.

  2. Effects of Cd and Pb pollution on soil enzymatic activities and soil microbiota

    Institute of Scientific and Technical Information of China (English)

    LIU Shuqing; YANG Zhixin; WANG Xiaomin; ZHANG Xiaogui; GAO Rutai; LIU Xia

    2007-01-01

    Based on a representative sampling method and pot experiment with different concentrations of Cd and Pd,the enzymatic activities(urease,phosphatase,catalase,invertase),population of bacteria,fungus and actinomycete in the soil,the Cd and Pd pollution status of soil samples(from the wastewater-irrigated area of Baoding suburb)were appraised.Unitary linear and nonlinear curve-fitting optimization models were applied in the research,and the relationship between Pb and Cd causing pollution and enzymatic activities of the tested soils were discussed.The research may provide a theoretical basis for protecting the environment in the region of Baiyangdian Lake,Hebei province,prevent soil pollution,and ascertain biochemical indexes,which reflect soil heavy metal pollution levels.The research results indicated that:(1)there was obvious accumulation of Pb and Cd in the wastewater-irrigated area,also the accumulation in wastewater-irrigated soil is more than that in fresh water-irrigated soil,and accumulation on surface layer was more than that in the lower layer.Pb and Cd contents in the tested soils exceeded the standards of soil background values for some major cities at home and abroad and the world soil Cd and Pb contents range.This means that the tested soil had reached a lightly polluted level;(2)there existed an obvious negative correlation between soil enzymatic activities and Pb and Cd contents in wastewaterirrigated soil,where the soil urease and catalase activities decreased obviously with the increase of Pb and Cd contents in soil.Therefore,the urease and catalase can be considered as biochemical indexes that reflect the degree of soil Pb and Cd pollution;(3)the pot experiments indicated that the influence of Cd on soil enzymatic activities was greater than that of Pb.Generally,the effect of Cd on soil phosphatase,urease,catalase is more obvious than that on invertase,while Pb has a more obvious effect on invertase than Cd;(4)pot experiments of triple cropping

  3. Ultrafast exciton relaxation dynamics of PbS and core/shell PbS/CdS quantum dots

    Institute of Scientific and Technical Information of China (English)

    WHEELER Damon A.; FITZMORRIS Bob C.; ZHAO HaiGuang; MA DongLing; ZHANG JinZhong

    2012-01-01

    Optical properties and ultrafast exciton relaxation dynamics in PbS and core/shell PbS/CdS quantum dots (QDs) have been studied using UV-vis absorption and fluorescence spectroscopy as well as femtosecond (fs) transient absorption spectroscopy.The electronic absorption spectrum of the PbS QDs features broad absorption in the entire near IR-vis-UV region with a monotonic increase in intensity towards shorter wavelength.Relative to PbS,the absorption of the core/shell PbS/CdS QDs shows a slight blue shift in the 600-800 nm region,due to the decrease of the PbS crystal size caused by the synthetic process of the core/shell structure,and increased absorption near 400 nm due to the CdS shell.The PL of the PbS/CdS QDs was ~2.6 times more intense than that of the PbS QDs,due to surface passivation of PbS by CdS,and blue-shifted,attributable to smaller PbS size and thereby stronger quantum confinement in the core/shell QDs.Fs transient absorption measurements of both systems showed a strong transient absorption feature from 600 to 750 nm following excitation at 750 nm.The transient absorption decays can be fit to a biexponential with time constants of 8 and 100 ps for PbS and 6 and 80 ps for PbS/CdS.The amplitude and lifetime of the fast component were excitation intensity dependent,with the amplitude increasing more than linearly with increasing excitation intensity and the lifetime decreasing with increasing intensity.The fast decay is attributed to exciton-exciton annihilation and it occurs more readily for the PbS/CdS than the PbS QDs,which is attributed to a lower density of trap states in the core/shell ODs,as supported by their stronger PL.

  4. Dispersion, speciation and adsorption treatment of heavy metals in the vicinity of the Shi-Heung Cu-Pb-Zn mine

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ho Song; Chon, Hyo Taek [Seoul National Univ., Seoul (Korea, Republic of)

    1995-10-01

    In order to investigate the dispersion patterns and speciation of Cu, Pb, Zn and Cd in soils, stream sediments and stream waters, geochemical studies of soil, stream sediment and stream water samples collected in the vicinity of the Shi-Heung Cu-Pb-Zn mine was carried out. Cation exchange capacity measurement, size analysis, X-ray diffraction analysis and batch test were performed to select applicable soil for adsorption treatment. The average content of Cu, Pb, Zn and Cd in soils collected from tailings and ore dressing plant is 1084 ppm, 2292 ppm, 3512 ppm and, 29.2 ppm, respectively, and therefore, tailings and ore dressing plant site may be the major contamination sources in this study area. The mean content of Cu, Pb, Zn and Cd in stream sediments is extremely high up to 794 ppm, 1633 ppm, 2946 ppm and 25.2 ppm, respectively. Tailing particles and heavy metal ions are dispersed along the tributary system. Results from the sequential extraction analysis indicate; (1) most of Cu is bound to organic matters and sulphides, (2) fraction of Pb is mainly bound to Fe and Mn oxides. Most of Zn is largely bound to Fe and Mn oxides and residual fraction. Ion exchangeable fraction of Cd is relatively higher than those of Cu, Pb and Zn. Batch test on soils collected from the kaolinite and/or pyrophyllite mines and from the control areas was carried out to select an applicable soil samples for adsorption treatment. The sample, S10, collected from the control area 2 (clay content 33.2%) shows the highest K{sub d} (distribution coefficient). Organic content in soils and several clay minerals shows relatively good correlation with K{sub d}. It means that applicable soils for adsorption treatment of heavy metals show high organic and clay content. (author). 37 refs., 9 tabs., 6 figs.

  5. Extracting Cu Diffusion Parameters in Polycrystalline CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Akis, Richard [Arizona State Univeristy; Brinkman, Daniel [Arizona State Univeristy; Sankin, Igor [First Solar; Fang, Tian [First Solar; Guo, Da [Arizona State Univeristy; Dragica, Vasileska [Arizona State Univeristy; Ringhofer, Christian [Arizona State University

    2014-06-13

    It is well known that Cu plays an important role in CdTe solar cell performance as a dopant. In this work, a finite-difference method is developed and used to simulate Cu diffusion in CdTe solar cells. In the simulations, which are done on a two-dimensional (2D) domain, the CdTe is assumed to be polycrystal-line, with the individual grains separated by grain boundaries. When used to fit experimental Cu concentration data, bulk and grain boundary diffusion coefficients and activation energies for CdTe can be extracted. In the past, diffusion coefficients have been typically obtained by fitting data to simple functional forms of limited validity. By doing full simulations, the simplifying assumptions used in those analytical models are avoided and diffusion parameters can thus be determined more accurately.

  6. Interactions of core–shell quantum dots with metal resistant bacterium Cupriavidus metallidurans: Consequences for Cu and Pb removal

    Energy Technology Data Exchange (ETDEWEB)

    Slaveykova, Vera I., E-mail: vera.slaveykova@unige.ch [Environmental Biogeochemistry and Ecotoxicology, Institute F.-A. Forel, Earth and Environment Science, Faculty of Sciences, University of Geneva, 10, route de Suisse, 1290 Versoix (Switzerland); Pinheiro, José Paulo [IBB/CBME, Department of Chemistry and Biochemistry, University of the Algarve, Gambelas Campus, 8005-139 Faro (Portugal); Floriani, Magali [IRSN/DEI/SECRE/LRE CEA Cadarache, 13115 Saint-Paul-Lez-Durance (France); Garcia, Miguel [School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Station 15, CH-1015 Lausanne (Switzerland)

    2013-10-15

    Highlights: • QDs associate with C. metallidurans in time and concentration dependent manner. • 12.9 nm size QDs adhere to the bacterial surface and enter the periplasmic space. • QDs bound significantly Cu and Pb. • QDs increase Cu and Pb content in C. metallidurans during short term exposure. -- Abstract: 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.

  7. The potential of Lumbricus rubellus as a bioaccumulator of excess Pb and Cd in organic media

    Directory of Open Access Journals (Sweden)

    M. Arifin

    2015-07-01

    Full Text Available Lead (Pb and cadmium (Cd are sources of serious problems in the environment due to their reactivity and toxicity. Lumbricus rubellus is an earthworm reared by people is expected to reduce Pb and Cd concentrations in the environments. The aim of this study was to explore the ability of Lumbricus rubellus in reducing excess of Pb and Cd in organic media generated from urban waste. Sixteen treatments (four levels of Pb concentration and four levels of Cd concentration were arranged in a completely randomized design with three replications. Each treatment was placed in a wooden pot of 20 cm x 20 cm x 25 cm, and supplied with 40 Lumbricus rubellus for 30 days. Results of this study showed that 20 and 40% of the earthworm could survive until day 30 in organic media contaminated with Pb and Cd, respectively. Pb accumulated in the earthworm bodies ranged from 0.03 to 211.42 mg/kg, while the Cd accumulated in the earthworm body ranged from 0.57 to 22.11 mg/kg. The bioaccumulation factor for Pb was 46.98%, while that of Cd was 53.83%t. The content of Pb in vermicompost ranged from 0.04 to 19.41 mg/kg, while that of Cd ranged from 0.01 to 1.58 mg/kg.

  8. Sensitized solar cells with colloidal PbS-CdS core-shell quantum dots

    NARCIS (Netherlands)

    Lai, Lai-Hung; Protesescu, Loredana; Kovalenko, Maksym V.; Loi, Maria A.

    2014-01-01

    We report on the fabrication of PbS-CdS (core-shell) quantum dot (QD)-sensitized solar cells by direct adsorption of core-shell QDs on mesoporous TiO2 followed by 3-mercaptopropionic acid ligand exchange. PbS-CdS QD-sensitized solar cells show 4 times higher efficiency with respect to solar cells se

  9. Comparison of chelates for enhancing Ricinus communis L. phytoremediation of Cd and Pb contaminated soil.

    Science.gov (United States)

    Zhang, Hanzhi; Guo, Qingjun; Yang, Junxing; Ma, Jie; Chen, Gang; Chen, Tongbin; Zhu, Guangxu; Wang, Jian; Zhang, Guangxin; Wang, Xin; Shao, Chunyan

    2016-11-01

    We studied chelate effects on castor bean (Ricinus communis L.) growth. These effects included Cd and Pb accumulation in plant tissues and the chemical behavior of Cd and Pb in the plant rhizosphere and non-rhizosphere. Tests were conducted in a glasshouse using the rhizobag method. Two castor bean cultivars (Zibo-3 and Zibo-9) were grown in soil contaminated with 3.53mg/kg Cd and 274mg/kg Pb. The soil was treated with citric acid (CA), ethylenediamine disuccinic acid (EDDS) or ethylenediamine tetraacetic acid (EDTA) (5mmol/kg). EDDS-treated soil produced 28.8% and 59.4% greater biomass for Zibo-3 and Zibo-9 respectively. In contrast, CA and EDTA inhibited the growth of the two cultivars. Zibo-9 had greater tolerance than Zibo-3 to chelate toxicity. Based on Cd and Pb plant uptake, EDDS could substitute for EDTA for phytoremediation of Cd in soil. EDTA was the most effective of the three chelates for Pb phytoremediation but it is less suitable for field use due to toxicology environmental persistence. Acid extractable Cd and Pb in the rhizosphere or reducible Cd and Pb in the non-rhizosphere of soil were the main influences on Cd and Pb accumulation in castor bean.

  10. Pb and Cd Contents in Soil, Water, and Trees at an Afforestation Site, South China.

    Science.gov (United States)

    Pei, Nancai; Chen, Bufeng; Liu, Shuguang

    2015-11-01

    Pb and Cd contents in 13 plantation tree species (leaf and branch components), soil, water (groundwater and river water) at a young (3-5 year-old) seashore afforestation stand were investigated in Nansha district, Guangzhou city in southern China. The results showed that (1) soil, rather than water or trees, had the highest content of both Pb (averagely 48.79 mg/kg) and Cd (0.50 mg/kg), demonstrating that soil might function as a major reservoir for extraneously derived heavy metals; (2) Pb content was higher in branches than in leaves, but Cd content appeared similar in both components, implying possibly different accumulation mechanisms in trees; (3) Pb and Cd appeared to accumulate differently among some tree taxa, whereas almost no significant difference was detected between introduced and indigenous species. The study indicated that trees were potentially useful to remediate sites contaminated with Pb and Cd in the urbanized areas.

  11. [Remediation of Cu-Pb-contaminated loess soil by leaching with chelating agent and biosurfactant].

    Science.gov (United States)

    Liu, Xia; Wang, Jian-Tao; Zhang, Meng; Wang, Li; Yang, Ya-Ti

    2013-04-01

    Because of its strong chelation, solubilization characteristics, the chelating agents and biosurfactant are widely used in remediation of heavy metals and organic contaminated soils. Ethylenediamine tetraacetic acid (EDTA), citric acid (CIT) and dirhamnolipid (RL2) were selected as the eluent. Batch experiments and column experiments were conducted to investigate the leaching effect of the three kinds of eluent, as well as the mixture of biosurfactant and chelating agent for Cu, Pb contaminated loess soil. The results showed that the leaching efficiencies of different eluent on Cu, Pb contaminated loess soil followed the sequence of EDTA > CIT > RL2. At an eluent concentration of 0.02 mol x L(-1), the Cu leaching efficiency was 62.74% (EDTA), 52.28% (CIT) and 15.35% (RL2), respectively; the Pb leaching efficiency was 96.10% (EDTA), 23.08% (CIT) and 14.42% (RL2), respectively. When the concentration of RL2 was 100 CMC, it had synergistic effects on the other two kinds of chelating agent in Cu leaching, and when the concentration of RL2 was 200 CMC, it had antagonism effects. The effect of RL2 on EDTA in Pb leaching was similar to that in Cu leaching. Pb leaching by CIT was inhibited in the presence of RL2. EDTA and CIT could effectively remove Cu and Pb in exchangeable states, adsorption states, carbonate salts and organic bound forms; RL2 could effectively remove Cu and Pb in exchangeable and adsorbed states.

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

    Science.gov (United States)

    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.

  13. Forest Gaps Inhibit Foliar Litter Pb and Cd Release in Winter and Inhibit Pb and Cd Accumulation in Growing Season in an Alpine Forest.

    Directory of Open Access Journals (Sweden)

    Jie He

    Full Text Available The release of heavy metals (such as Pb and Cd from foliar litter play an important role in element cycling in alpine forest ecosystems. Although natural forest gaps could play important roles in the release of heavy metals from foliar litter by affecting the snow cover during the winter and solar irradiation during the growing season, few studies have examined these potential roles. The objectives of this study were to document changes in Pb and Cd dynamics during litter decomposition in the center of gaps and under closed canopies and to investigate the factors that controlled these changes during the winter and growing seasons.Senesced foliar litter from six dominant species, including Kangding willow (Salix paraplesia, Masters larch (Larix mastersiana, Mingjiang fir (Abies faxoniana, Alpine azalea (Rhododendron lapponicum, Red birch (Betula albosinensis and Mourning cypress (Sabina saltuaria, was placed in litterbags and incubated between the gap center and closed canopy conditions in an alpine forest in the eastern region of the Tibetan Plateau. The litterbags were sampled at the snow formation stage, snow coverage stage, snow melt stage and during the growing season. The Pb and Cd concentrations in the sampled foliar litter were determined by acid digestion (HNO3/HClO4.Over one year of decomposition, Pb accumulation and Cd release from the foliar litter occurred, regardless of the foliar litter species. However, Pb and Cd were both released from the foliar litter during the winter and accumulated during the growing season. Compared with the gap center and the canopy gap edge, the extended gap edge and the closed canopy showed higher Pb and Cd release rates in winter and higher Pb and Cd accumulation rates during the growing season, respectively. Statistical analyses indicate that the dynamics of Pb were significantly influenced by frequent freeze-thaw cycles in winter and appropriate hydrothermal conditions during the growing season, the

  14. Interaction of Pb and Cd in Soil—Water—Plant System and Its Mechanism: Ⅱ.Pb—Cd Interaction in Rhizosphere

    Institute of Scientific and Technical Information of China (English)

    CHENHUAIMAN; LINQI; 等

    1998-01-01

    The interaction of Pb-Cd can be observed not only in the uptake process of elements by plants and in their influence on the growth,but also in rhizosphere.The changes in extractable Cd and Pb concentrations in the rhizosphere soil of rice plants ,root exudates from wheat and wheat plant and their complexing capacity,with Pa and Cd were investigated under different Pb and Cd treatments.Results showed that the concentration of extractable Cd in the rhizosphere of rice in red soil was markedly increased by Pb-Cd interaction,It increased by 56% in the treatment with Pb and Cd added against that in the treatment with only Cd added in soil . The considerable differences in both composition and amount of root exudate from wheat and rice were found among different treatments.Pb and Cd might be complexed by root exudates ,The concentrations of free Pb and Cd in the solution were increased markedly by adding root exudate from wheat and decreased by that from rice due to Pd-Cd interaction.The distribution patterns of Pb and Cd in roots were affected by Pb-Cd interaction,which accelerated transport of Pb into internal tissue and retarded accumulation of Cd in external tissue.

  15. CdS/PbS co-sensitized ZnO nanorods and its photovoltaic properties

    Science.gov (United States)

    Liu, Chengcheng; Liu, Zhifeng; Li, Yabin; Ya, Jing; E, Lei; An, Li

    2011-06-01

    Nanoparticles co-sensitized nanorods were designed and prepared by assembled CdS and PbS nanoparticles over ZnO nanorods using successive ionic layer adsorption and reaction (SILAR) method. The results showed that the uniform CdS and PdS nanoparticles could be deposited on the lateral and top of the ZnO nanorods when the precursor concentration was 0.05 M and 0.02 M, respectively. Solar cells based on CdS and PbS nanoparticles sensitized ZnO nanorods arrays were assembled successfully. A cell efficiency of 0.38% was obtained in ZnO/CdS/PbS in comparison with ZnO/PbS/CdS mainly due to the stepwise band edge structure constructed in this system except the coverage density of nanoparticles.

  16. Biosorption of Cu2+ and Pb2+ using sophora alopecuroides residue

    Science.gov (United States)

    Feng, N.; Fan, W.; Zhu, M.; Zhang, Y.

    2016-08-01

    Sophora alopecuroides residue (SAP), a kind of traditional Chinese herbal medicine residue, was developed in an alternative biosorbent for the removal Cu2+ and Pb2+ in simulated wastewater. The morphology and surface texture of SAP were characterized by scanning electron microscopy, which showed a loose and porous structure. The biosorption experiments of Cu2+ and Pb2+ onto SAP were investigated by using batch techniques. High biosorption percentage appeared at pH values of 4.5-6.0. The experimental data followed the second-order kinetic model well. Equilibrium fit with the Langmuir isotherm model well. The maximum biosorption capacity of an adsorbent at 25 °C was respectively 60.6 mg/g Cu2+ and 128.1 mg/g Pb2+. The findings of the present study show that SAP is an attractive and effective biosorbent for Cu2+ and Pb2+.

  17. Predictive GIS Model for Potential Mapping of Cu, Pb, Zn Mineralization

    Institute of Scientific and Technical Information of China (English)

    Tarik. B. Benomar; BIAN Fuling

    2006-01-01

    The geologic features indicative of Cu, Pb, Zn mineral deposits in a area are fractures (structure), and host rock sediments. Datasets used include Cu, Pb, Zn deposit points record, geological data, remote sensing imagery (Landsat TM5). The mineral potential of the study area is assessed by means of GIS based geodata integration techniques for generating predictive maps. GIS predictive model for Cu, Pb, Zn potential was carried out in this study area (Weixi) using weight of evidence. The weights of evidence modeling techniques is the data driven method in which the spatial associations of the indicative geologic features with the known mineral occurrences in the area are quantified, and weights statistically assigned to the geologic features. The best predictive map generated by this method defines 24% the area having potential for Cu, Pb, Zn mineralization further exploration work.

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

    Science.gov (United States)

    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.

  19. Pengaruh Medium Tercemar Logam Pb dan Cu terhadap Pertumbuhan Nannochloropsis Salina

    OpenAIRE

    Abd.Wahid Wahab; Yusafir Hala; Fibiyanthy

    2013-01-01

    Penelitian ini dilakukan dengan tujuan memanfaatkan fitoplankton Nannochloropsis salina sebagai biosorben untuk ion logam Pb dan Cu di perairan. Pada penelitian ini pemaparan ion logam Pb dan Cu dengan variasi konsentrasi masing-masing 10, 30, dan 50 ppm dilakukan di awal masa pertumbuhan fitoplankton N. salina dalam Medium Conwy pada salinitas 30 ???, aerasi dan pencahayaan kontinyu, serta suhu ruangan 20 ??C. Konsentrasi ion logam ditentukan dengan menggunakan spektrofotometer serapan atom ...

  20. Antioxidant response of Phragmites australis to Cu and Cd contamination.

    Science.gov (United States)

    Rocha, A Cristina S; Almeida, C Marisa R; Basto, M Clara P; Vasconcelos, M Teresa S D

    2014-11-01

    Metals are known to induce oxidative stress in plant cells. Antioxidant thiolic compounds are known to play an important role in plants׳ defence mechanisms against metal toxicity but, regarding salt marsh plants, their role is still very poorly understood. In this work, the involvement of non-protein thiols (NPT), such as cysteine (Cys), reduced glutathione (GSH), oxidised glutathione (GSSG) and total acid-soluble SH compounds (total thiols), in the tolerance mechanisms of the marsh plant Phragmites australis against Cu and Cd toxicity was assessed. Specimens of this plant, freshly harvested in an estuarine salt marsh, were exposed, for 7 days, to rhizosediment soaked with the respective elutriate contaminated with Cu (0, 10 and 100 mg/L) or Cd (0, 1, 10 mg/L). In terms of NPT production, Cu and Cd contamination induced different responses in P. australis. The content of Cys increased in plant tissue after plant exposure to Cu, whereas Cd contamination led to a decrease in GSSG levels. In general, metal contamination did not cause a significant variation on GSH levels. Both metals influenced, to some extent, the production of other thiolic compounds. Despite the accumulation of considerable amounts of Cu and Cd in belowground tissues, no visible toxicity signs were observed. So, antioxidant thiolic compounds were probably involved in the mechanisms used by P. australis to alleviate metal toxicity. As P. australis is considered suitable for phytostabilising metal-contaminated sediments, understanding its tolerance mechanisms to toxic metals is important to optimise the conditions for applying this plant in phytoremediation procedures.

  1. Photovoltaic properties of Cu-doped CH3NH3PbI3 with perovskite structure

    Science.gov (United States)

    Shirahata, Yasuhiro; Oku, Takeo

    2017-01-01

    Photovoltaic properties of copper (Cu)-doped perovskite (CH3NH3PbCuxI3+x) photovoltaic devices with different Cu content were investigated. The CH3NH3PbCuxI3+x films were polycrystalline with a tetragonal system, and their lattice constants and crystallite size varied with Cu doping. Compared to conversion efficiencies of non-doped CH3NH3PbI3 photovoltaic device, those of CH3NH3PbCuxI3+x photovoltaic devises increased. The improvement of photovoltaic properties was attributed to partial substitution of Cu at the Pb sites.

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

    Science.gov (United States)

    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.

  3. EMPIRICAL MODELS OF PB AND CD PARTITIONING USING DATA FROM 13 SOILS, SEDIMENTS AND AQUIFER MATERIALS

    Science.gov (United States)

    Lead (Pb) and cadmium (Cd) are two of the most common toxicants found in contaminated environments. Because solubilization of these metallic elements from the solid phase can influence their fate, transport and bioavailability, the partitioning coefficient (Kd) for these metals ...

  4. Cu-doped CdS and its application in CdTe thin film solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Yi [School of Automation, Wuhan University of Technology, Wuhan, Hubei 430070 (China); College of Electronic and Information Engineering, Hankou University, Wuhan, Hubei 430212 (China); Yang, Jun; Yang, Ruilong; Shen, Kai; Wang, Dezhao [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang, Deliang, E-mail: eedewang@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2016-01-15

    Cu is widely used in the back contact formation of CdTe thin film solar cells. However, Cu is easily to diffuse from the back contact into the CdTe absorber layer and even to the cell junction interface CdS/CdTe. This phenomenon is generally believed to be the main factor affecting the CdTe solar cell stability. In this study Cu was intentionally doped in CdS thin film to study its effect on the microstructural, optical and electrical properties of the CdS material. Upon Cu doping, the V{sub Cd{sup −}} and the surface-state-related photoluminescence emissions were dramatically decreased/quenched. The presence of Cu atom hindered the recrystallization/coalescence of the nano-sized grains in the as-deposited CdS film during the air and the CdCl{sub 2} annealing. CdTe thin film solar cell fabricated with Cu-doped CdS window layers demonstrated much decreased fill factor, which was induced by the increased space-charge recombination near the p-n junction and the worsened junction crystalline quality. Temperature dependent current-voltage curve measurement indicated that the doped Cu in the CdS window layer was not stable at both room and higher temperatures.

  5. ICP-MS Determination of Cr, Cd, Ni, Cu, Pb and Zn in Atmospheric Dust Fall%电感耦合等离子体质谱法测定大气降尘中铬、镉、镍、铜、铅和锌

    Institute of Scientific and Technical Information of China (English)

    彭萌; 诸堃; 陈莲红; 魏春蓉

    2012-01-01

    用电感耦合等离子体质谱法测定大气降尘中铬、镉、镍、铜、铅和锌等有害元素的含量。试样于敞开的聚四氟乙烯坩埚中用氢氟酸和硝酸消解,运用干扰方程校正质谱干扰。方法的测定下限(10s)在0.039-0.87μg·g-1之间。通过分析1个地质标准物质(GBW 07404)对所提出方法的准确度和精密度做了考核,所得测定结果与标准物质的认定值相吻合,各元素测定结果的相对标准偏差(n=11)均小于5.0%。%A method of ICP-MS for the determination of harmful elements, i. e. , Cr, Cd, Ni, Cu, Pb and Zn in atmospheric dust fall was proposed. Samples were digested with HF and HNO3 in an open PTFE crucible. The mass spectrometry interferences were corrected by using interference equations. Lower limits of determination (10s) found for the 6 elements were in the range of 0. 039--0. 87μg·g-1. Accuracy and precision of the proposed method were tested by analyzing a geological CRM (GBW 07404), giving results in consistency with the certified values and values of RSD's (n=11) less than 5.0%.

  6. Adsorption of Cd(II) and Pb(II) from aqueous solutions on activated alumina.

    Science.gov (United States)

    Naiya, Tarun Kumar; Bhattacharya, Ashim Kumar; Das, Sudip Kumar

    2009-05-01

    The ability of activated alumina as synthetic adsorbent was investigated for adsorptive removal of Cd(II) and Pb(II) ions from aqueous solutions. Various physico-chemical parameters such as pH, initial metal ion concentration, and adsorbent dosage level and equilibrium contact time were studied. The optimum solution pH for adsorption of Cd(II) and Pb(II) from aqueous solutions was found to be 5. Kinetics data were best described by pseudo-second order model. The effective particle diffusion coefficient of Cd(II) and Pb(II) are of the order of 10(-10) m(2)/s. Values of mass transfer coefficient were estimated as 4.868x10(-6) cm/s and 6.85x10(-6) cm/s for Cd(II) and Pb(II) adsorption respectively. The equilibrium adsorption data for Cd(II) and Pb(II) were better fitted to Langmuir adsorption isotherm model. The thermodynamic studies indicated that the adsorption was spontaneous and exothermic for Cd(II) adsorption and endothermic for Pb(II). The sorption energy calculated from Dubinin-Radushkevich isotherm were 11.85 kJ/mol and 11.8 kJ/mol for the adsorption of Cd(II) and Pb(II) respectively which indicated that both the adsorption processes were chemical in nature. Desorption studies were carried out using dilute mineral acids. Application studies carried out using industrial waste water samples containing Cd(II) and Pb(II) showed the suitability of activated alumina in waste water treatment plant operation.

  7. Adsorption behavior of Pb2+ and Cd2+ ions on bauxite flotation tailings

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-hua; LAN Ye; HUANG Chuan-bing

    2008-01-01

    The adsorption behavior of Pb2+ and Cd2+ ions on bauxite flotation railings was investigated to demonstrate the adsorptivity of the bauxite flotation tailings. The adsorption percentage of Pb2+ and Cd2+ ions as a function of adsorbent dosage, solution pH value and shaking time were determined by batch experiments. The maximum adsorption percentage of 99.93% for Pb2+ ions and 99.75% for Cd2+ ions were obtained by using bauxite flotation railings as adsorbent. The methods, such as zeta potentials, specific surface area measurements and the analysis of adsorption kinetics, were introduced to analyze the adsorption mechanisms of the Pb2+ ions on bauxite flotation tailings. The isoelectric point of bauxite flotation railings shifts from 3.6 to 5.6 in the presence of Pb2+ ions. The specific surface area of bauxite flotation tailings changes from 12.57 to 20.63 m2/g after the adsorption of Pb2+ ions. These results indicate that a specific adsorption of the cation species happens on the surface of bauxite flotation tailings. Adsorption data of Pb2+ ions on the surface of bauxite flotation tailings can be well described by Langmuir model, and the pseudo-second-order kinetic model provides the best correlation for the adsorption data of Pb2+ and Cd2+ ions on bauxite flotation railings.

  8. Alleviating effects of exogenous NO on tomato seedlings under combined Cu and Cd stress.

    Science.gov (United States)

    Wang, Yi-Jun; Dong, Yu-Xiu; Wang, Juan; Cui, Xiu-Min

    2016-03-01

    To investigate the effect of NO on the different origin and regulation of oxidative stress of Cu and/or Cd, tomato seedlings were treated with Cu, Cd, or Cu + Cd in a nutrient solution culture system. The main effect of Cu(2+) was a significant reduction in root activity and nitrate reductase (NR) activity, which was similar to that under 50 μM Cd treatment, but promoted Cu accumulation. The supply of Cu under Cd treatment decreased Cd concentration, while not altered Cu concentration by contrast with Cu treatment, which is suggestive of a replacement of Cu(2+) with Cd(2+) and effective decrease in the boiotoxicity of 50 μM Cd(2+) to tomato seedlings. However, NO alleviated the restriction to NR activity significantly and made the biomass of tomato seedlings recover under Cd treatment, and also increased root activity under Cu and Cu + Cd treatment. Exogenous NO markedly reduced the absorption and transportation of Cu but did not obviously change the translocation of Cd to the aboveground parts under Cu + Cd treatment. Both metals induced lipid peroxidation via the decreasing activation of antioxidant enzymes. The antioxidant enzyme system worked differently under Cu, Cd, or Cu + Cd stress. The activities of peroxidase (POD) and catalase (CAT) were higher under single Cd stress than under the control. Meanwhile, Cu + Cd treatment decreased the activities of POD, superoxide dismutase (SOD), and ascorbic acid peroxidase (APX). Exogenous NO increased POD and SOD activities in the leaves and roots, and CAT activity in the roots under combined Cu and Cd stress. These results suggest that a different response and regulation mechanism that involves exogenous NO is present in tomato seedlings under Cu and Cd stress.

  9. Availability of heavy metals (Cd, Pb, And Cr) in agriculture from commercial fertilizers.

    Science.gov (United States)

    Nacke, H; Gonçalves, A C; Schwantes, D; Nava, I A; Strey, L; Coelho, G F

    2013-05-01

    The purpose of this study was to investigate the availability of the heavy metals cadmium (Cd), lead (Pb), and chromium (Cr) to soil and maize plants fertilized with different sources and doses of zinc (Zn) in a Rhodic Eutrudox soil. For that purpose, concentrations of Cd, Pb, and Cr were evaluated in leaf tissue and grains of maize plants and in 0-20 and 20-40 cm soil layers after fertilization with four doses of Zn from eight different sources of fertilizer. There was no accumulation of Cd, Pb, and Cr in maize grain and Cd and Cr in leaf tissue of the plants; nevertheless, there was accumulation of Pb in leaf tissue, showing its availability throughout different sources of Zn and consequent uptake by plants. Regarding the soil, it was observed that fertilizer from the different sources made Cd, Pb, and Cr available at increasing amounts proportional to increased Zn doses. Under experimental conditions, fertilization with Zn increased concentrations of heavy metals Cd, Pb and Cr in soil, further highlighting the importance of conducting more studies related to the application of mineral fertilizers for micronutrient supply and the availability of heavy metals.

  10. Cu-doped CdS and its application in CdTe thin film solar cell

    Directory of Open Access Journals (Sweden)

    Yi Deng

    2016-01-01

    Full Text Available Cu is widely used in the back contact formation of CdTe thin film solar cells. However, Cu is easily to diffuse from the back contact into the CdTe absorber layer and even to the cell junction interface CdS/CdTe. This phenomenon is generally believed to be the main factor affecting the CdTe solar cell stability. In this study Cu was intentionally doped in CdS thin film to study its effect on the microstructural, optical and electrical properties of the CdS material. Upon Cu doping, the VCd− and the surface-state-related photoluminescence emissions were dramatically decreased/quenched. The presence of Cu atom hindered the recrystallization/coalescence of the nano-sized grains in the as-deposited CdS film during the air and the CdCl2 annealing. CdTe thin film solar cell fabricated with Cu-doped CdS window layers demonstrated much decreased fill factor, which was induced by the increased space-charge recombination near the p-n junction and the worsened junction crystalline quality. Temperature dependent current-voltage curve measurement indicated that the doped Cu in the CdS window layer was not stable at both room and higher temperatures.

  11. Cu-doped CdS and its application in CdTe thin film solar cell

    Science.gov (United States)

    Deng, Yi; Yang, Jun; Yang, Ruilong; Shen, Kai; Wang, Dezhao; Wang, Deliang

    2016-01-01

    Cu is widely used in the back contact formation of CdTe thin film solar cells. However, Cu is easily to diffuse from the back contact into the CdTe absorber layer and even to the cell junction interface CdS/CdTe. This phenomenon is generally believed to be the main factor affecting the CdTe solar cell stability. In this study Cu was intentionally doped in CdS thin film to study its effect on the microstructural, optical and electrical properties of the CdS material. Upon Cu doping, the VCd- and the surface-state-related photoluminescence emissions were dramatically decreased/quenched. The presence of Cu atom hindered the recrystallization/coalescence of the nano-sized grains in the as-deposited CdS film during the air and the CdCl2 annealing. CdTe thin film solar cell fabricated with Cu-doped CdS window layers demonstrated much decreased fill factor, which was induced by the increased space-charge recombination near the p-n junction and the worsened junction crystalline quality. Temperature dependent current-voltage curve measurement indicated that the doped Cu in the CdS window layer was not stable at both room and higher temperatures.

  12. Orientation dependence of heterogeneous nucleation at the Cu-Pb solid-liquid interface

    Science.gov (United States)

    Palafox-Hernandez, J. Pablo; Laird, Brian B.

    2016-12-01

    In this work, we examine the effect of surface structure on the heterogeneous nucleation of Pb crystals from the melt at a Cu substrate using molecular-dynamics (MD) simulation. In a previous work [Palafox-Hernandez et al., Acta Mater. 59, 3137 (2011)] studying the Cu/Pb solid-liquid interface with MD simulation, we observed that the structure of the Cu(111) and Cu(100) interfaces was significantly different at 625 K, just above the Pb melting temperature (618 K for the model). The Cu(100) interface exhibited significant surface alloying in the crystal plane in contact with the melt. In contrast, no surface alloying was seen at the Cu(111) interface; however, a prefreezing layer of crystalline Pb, 2-3 atomic planes thick and slightly compressed relative to bulk Pb crystal, was observed to form at the interface. We observe that at the Cu(111) interface the prefreezing layer is no longer present at 750 K, but surface alloying in the Cu(100) interface persists. In a series of undercooling MD simulations, heterogeneous nucleation of fcc Pb is observed at the Cu(111) interface within the simulation time (5 ns) at 592 K—a 26 K undercooling. Nucleation and growth at Cu(111) proceeded layerwise with a nearly planar critical nucleus. Quantitative analysis yielded heterogeneous nucleation barriers that are more than two orders of magnitude smaller than the predicted homogeneous nucleation barriers from classical nucleation theory. Nucleation was considerably more difficult on the Cu(100) surface-alloyed substrate. An undercooling of approximately 170 K was necessary to observe nucleation at this interface within the simulation time. From qualitative observation, the critical nucleus showed a contact angle with the Cu(100) surface of over 90°, indicating poor wetting of the Cu(100) surface by the nucleating phase, which according to classical heterogeneous nucleation theory provides an explanation of the large undercooling necessary to nucleate on the Cu(100) surface

  13. Removal of Cu (II) and Pb (II) from Aqueous Solution using engineered Iron Oxide Nanoparticles.

    Science.gov (United States)

    Tamez, Carlos; Hernandez, Rebecca; Parsons, J G

    2016-03-01

    Nano-sized Fe3O4 and Fe2O3 were synthesized using a precipitation method. The nanomaterials were tested as adsorbents for the removal of both Cu(2+) and Pb(2+) ions. The nanomaterials were characterized using X-ray powder diffraction to determine both the phase and the average grain size of the synthesized nanomaterials. Batch pH studies were performed to determine the optimum binding pH for both the Cu(2+) and Pb(2+) to the synthesized nanomaterials. The optimum binding was observed to occur at pH 4 and above. Time dependency studies for Cu(2+) and Pb(2+) showed the binding occurred within the first five minutes of contact and remained constant up to 2 hours of contact. Isotherm studies were utilized to determine the binding capacity of each of the nanomaterials for Cu(2+) and Pb(2+). The binding capacity of Fe3O4 with Cu(2+) and Pb(2+) were 37.04 mg/g and 166.67 mg/g, respectively. The binding capacities of the Fe2O3 nanomaterials with Cu(2+) and Pb(2+) were determined to be 19.61 mg/g and 47.62 mg/g, respectively. In addition, interference studies showed no significant reduction in the binding of either Cu(2+) or Pb(2+) to the Fe3O4 or Fe2O3 nanomaterials in the presence of solutions containing the individual ions Na(+), K(+), Mg(2+) and Ca(2+) or a solution consisting of a combination of all the aforementioned cations in one solution.

  14. Sorption Potentials of Waste Tyre for Some Heavy Metals (Pb Cd in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Austin Kanayo ASIAGWU

    2009-07-01

    Full Text Available An investigation into the adsorption potential of activated and inactivated waste tyre powders for some heavy metals (Pb2+ and Cd2+ in their aqueous solution has been studied. The result indicated that inactivated waste tyre is a good non-conventional adsorbent for the removal of Cd from aqueous solution. A total of 93.3% of Cadmium contents was removed. The inactivated waste type proved a good adsorbent for the removal of Pb2+ 5g of 500mm activated tyre removed over 86.66% of Pb2+ from solution.

  15. Effects of Cu, Zn and Pb Combined Pollution on Soil Hydrolase Activities

    Directory of Open Access Journals (Sweden)

    FENG Dan

    2015-08-01

    Full Text Available To study the relations between soil enzyme activities and heavy metal pollution, the combined effects of Cu, Zn and Pb on the three hydrolase activities, including invertase(IN, urease(Uand alkaline phosphatase(ALPwere investigated via an orthogonal experiment. Results showed as the following: When the concentration of Cu was 400 mg·kg-1, the U and ALP activities were decreased 51% and 44%, separately; When Zn was at 500 mg·kg-1, IN and ALP activities were only decreased 3% and 9%, while U activity was increased; When Pb was at 500 mg·kg-1, IN and U activities were increased, while ALP activity was decreased 13%. As a whole, Cu was considered as the most remarkable influence factor for IN, U and ALP activity regardless of interactions among the heavy metals, Zn came second, and Pb mainly showed activation. Considering interactions, Cu×Zn could significantly influence U activity(P<0.05, effects of Cu×Pb and Cu×Zn on ALP activity were remarkable(95% confidence interval. The response of ALP activity was more sensitive than the other two enzymes. Soil ALP activity might be a sensitive tool for assessing the pollution degree of Cu.

  16. 壳聚糖对Cd2+和Pb2+的吸附作用%Adsorption of Cd2+ and Pb2+ by chitosan

    Institute of Scientific and Technical Information of China (English)

    程珊珊; 杨锡洪; 章超桦; 解万翠; 秦小明; 卢虹玉

    2011-01-01

    At present, with the development of industry and agriculture, heavy metal contamination of environment is intensifying ,and the toxic effects on the human beings have attracted extensive attention. For the development of new adsorbent, reducing the pollution of heavy metals in water body, the chitosans were used to investigate the adsorptions of two metals of Cd2+ and Pb2+ in an aqueous solution. The absorption properties of chitosan were evaluated by the effects of pH, temperature, reaction time, adsorbent dose and initial metal ion concentration. The results showed that at pH 7 -8 and pH 5 -6, the chitosan had the best absorption of Cd2+ and Pb2+ ,respectively; low temperature was beneficial to absorption; the maximum absorption of Cd2+ was at 8 h, but of Pb2+ it always increased in the experimental period; the absorption of Cd2+ and Pb2+ was enhanced with the increase of chitosan amount; initial metal ion concentration had little effect to Cd2+ ,but at high metal concentration,the absorption of Pb2+ was significantly reduced. At the same time, the dynamical and the equilibrium isotherm adsorption studies of Cd2 + and Pb2+ followed the Lagergren second-order kinetic equation and the Langmuir isotherm equation in the concentration range studied,respectively. Conclusion: the adsorption capacity of chitosan is different with the changes of metal ions, in single metal solution,the adsorption capacity of chitosan for Cd2+ is stronger than Pb2+. Finally, this work systematically studies the adsorption conditions and performance of chitosan for Cd2+ and Pb2+ which may provide theory basis for chitson as heavy metals adsorbent.%为开发新型吸附剂,降低重金属对水体的污染,研究了壳聚糖对Cd2+和Pb2+的吸附条件,探讨了pH、温度、反应时间、壳聚糖添加量和金属离子初始浓度等因素对壳聚糖吸附性能的影响.结果表明,pH 7~8和pH 5~6条件下壳聚糖对Cd2+和pb2+的吸附能力最强;低温

  17. Multifunctional nanocomposites Fe3O4@SiO2-EDTA for Pb(II) and Cu(II) removal from aqueous solutions

    Science.gov (United States)

    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.

  18. Phytoextraction of Pb and Cd from a superfund soil: effects of amendments and croppings.

    Science.gov (United States)

    Bricker, T J; Pichtel, J; Brown, H J; Simmons, M

    2001-01-01

    In a growth chamber, maize (Zea mays) and Indian mustard (Brassica juncea) were grown over two croppings in soil from a Superfund site (PbTotal = 65,200 mg/kg and CdTotal = 52mg/kg). Soil treatments consisted of ethylenediaminetetraacetic acid, sodium citrate and composted sewage sludge, each at two rates (EDTA .05%, EDTA .2%, citrate .05%, citrate .2%, CSS 5% and CSS 10%, respectively). In most cases, the EDTA and citrate treatments were superior in terms of solubilizing soil Pb for root uptake and translocation into above-ground biomass. In the first maize crop, the EDTA .2% treatment resulted in 2,435 and 9,389mg/kg Pb in shoot and root tissues, respectively. The CSS treatments typically resulted in lowest Pb and Cd removal efficiencies. Lead remaining in the soil after two croppings was mainly associated with the carbonate, organic, and residual fractions, which represent the less bioavailable forms. Soil Cd was generally more mobile for plant uptake than soil Pb. The EDTA .2% and citrate treatments were most successful in promoting Cd uptake by both maize and mustard. Although Pb concentrations (mg/kg tissue) were lower for maize than mustard, the former removed more total Pb (0.2 mg per pot, mean over all treatments), compared to mustard (0.03 mg), by virtue of its higher biomass production.

  19. Cu and Cd Adsorption on Carbon Aerogel and Xerogel

    Directory of Open Access Journals (Sweden)

    Cotet L. C.

    2013-04-01

    Full Text Available Carbon aerogel (CA and xerogel (CX were proposed as new carbon adsorbent materials for Cu and Cd ions from contaminated water (synthetic water samples. These materials were prepared by a sol-gel process that involves a polycondensation of resorcinol and formaldehyde in Na2CO3 catalysis, followed by a drying step, either in supercritical conditions of CO2 to aerogel obtaining or in normal conditions to xerogel obtaining, and a pyrolytic step. Nitrogen adsorption, AFM, SEM, TEM and XRD were used for morpho-structural adsorbent investigation. Cu and Cd ions adsorption experiments were carried out in batch conditions under magnetic stirring. Adsorbent quantity and grain size influence over the adsorption efficiency were considered. Adsorption results expressed as adsorption capacities showed that prepared CA is a better adsorbent than CX. Adsorption capacities up to 14.2 mg g-1 and 8.5 mg g-1 were obtained for Cd2+ and Cu2+ adsorption on CA, respectively.

  20. Immobilization of Zn, Cu, and Pb in contaminated soils using phosphate rock and phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Cao Xinde [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)] [Soil and Water Science Department, University of Florida, Gainesville, FL 32611 (United States); Wahbi, Ammar [Soil Science Department, Faculty of Agriculture, University of Aleppo, Aleppo (Syrian Arab Republic); Ma, Lena, E-mail: lqma@ufl.edu [Soil and Water Science Department, University of Florida, Gainesville, FL 32611 (United States); Li Bing; Yang Yongliang [National Research Center for Geoanalysis, Beijing 100037 (China)

    2009-05-30

    Considerable research has been done on P-induced Pb immobilization in Pb-contaminated soils. However, application of P to soils contaminated with multiple heavy metals is limited. The present study examined effectiveness of phosphoric acid (PA) and/or phosphate rock (PR) in immobilizing Pb, Cu, and Zn in two contaminated soils. The effectiveness was evaluated using water extraction, plant uptake, and a simple bioaccessibility extraction test (SBET) mimicking metal uptake in the acidic environment of human stomach. The possible mechanisms for metal immobilization were elucidated using X-ray diffraction, scanning electron microscopy, and chemical speciation program Visual MINTEQ. Compared to the control, all P amendments significantly reduced Pb water solubility, phytoavailability, and bioaccessibility by 72-100%, 15-86%, and 28-92%, respectively. The Pb immobilization was probably attributed to the formation of insoluble Pb phosphate minerals. Phosphorus significantly reduced Cu and Zn water solubility by 31-80% and 40-69%, respectively, presumably due to their sorption on minerals (e.g., calcite and phosphate phases) following CaO addition. However, P had little effect on the Cu and Zn phytoavailability; while the acid extractability of Cu and Zn induced by SBET (pH 2) were even elevated by up to 48% and 40%, respectively, in the H{sub 3}PO{sub 4} treatments (PA and PR + PA). Our results indicate that phosphate was effective in reducing Pb availability in terms of water solubility, bioaccessibility, and phytoavailability. Caution should be exercised when H{sub 3}PO{sub 4} was amended to the soil co-contaminated with Cu and Zn since the acidic condition of SBET increased Cu and Zn bioaccessibility though their water solubility was reduced.

  1. Immobilization of Zn, Cu, and Pb in contaminated soils using phosphate rock and phosphoric acid.

    Science.gov (United States)

    Cao, Xinde; Wahbi, Ammar; Ma, Lena; Li, Bing; Yang, Yongliang

    2009-05-30

    Considerable research has been done on P-induced Pb immobilization in Pb-contaminated soils. However, application of P to soils contaminated with multiple heavy metals is limited. The present study examined effectiveness of phosphoric acid (PA) and/or phosphate rock (PR) in immobilizing Pb, Cu, and Zn in two contaminated soils. The effectiveness was evaluated using water extraction, plant uptake, and a simple bioaccessibility extraction test (SBET) mimicking metal uptake in the acidic environment of human stomach. The possible mechanisms for metal immobilization were elucidated using X-ray diffraction, scanning electron microscopy, and chemical speciation program Visual MINTEQ. Compared to the control, all P amendments significantly reduced Pb water solubility, phytoavailability, and bioaccessibility by 72-100%, 15-86%, and 28-92%, respectively. The Pb immobilization was probably attributed to the formation of insoluble Pb phosphate minerals. Phosphorus significantly reduced Cu and Zn water solubility by 31-80% and 40-69%, respectively, presumably due to their sorption on minerals (e.g., calcite and phosphate phases) following CaO addition. However, P had little effect on the Cu and Zn phytoavailability; while the acid extractability of Cu and Zn induced by SBET (pH 2) were even elevated by up to 48% and 40%, respectively, in the H(3)PO(4) treatments (PA and PR+PA). Our results indicate that phosphate was effective in reducing Pb availability in terms of water solubility, bioaccessibility, and phytoavailability. Caution should be exercised when H(3)PO(4) was amended to the soil co-contaminated with Cu and Zn since the acidic condition of SBET increased Cu and Zn bioaccessibility though their water solubility was reduced.

  2. TELAAHAN LOGAM BERAT Pb DAN Cd PADA SEDIMEN DI PERAIRAN BARAT LAUT DUMAI – RIAU

    Directory of Open Access Journals (Sweden)

    Syahminan Syahminan

    2015-08-01

    Full Text Available This research was conducted in Dumai sea western waters, Riau Province. Dumai marine waters are part of the territorial waters of Riau that relate directly to the Strait of Malacca, and are at Rupat Strait region, and has a high accessibility of the region, both locally and internationally. Dumai waters is also an estuary waters affected by the activities of the land, and the waters that receive input from various types of waste from various activities in Dumai city and surrounding areas. The research was aimed to knowing the general condition of the Dumai sea western waters, analyzing the content of Pb and Cd in sediments, observing the correlation between organic matter and heavy metal of Pb and Cd, and find out the status of pollution Dumai Sea Western Waters by comparing the results of the analysis with some quality standard countries, The method used is a survey method. Based on the Decree of The Minister of Environment No. 51 of 2004, that the general condition of the Dumai sea western waters still can support the life activities of marine organisms in the waters. The results showed that the concentrations of Pb and Cd in sediments of Dumai is below the threshold value. The results of simple linear regression analysis of heavy metals Pb and Cd with organic matter content showed that the concentration of heavy metals Pb and Cd is not influenced by organic matter content or have a very weak correlation with linear regression equation consecutive y = 0,0834x + 7,7866 and y = -0,001x + 0,0559. The status of pollution of Dumai sea western waters for Pb 8,76 µg/g and Cd 0,04 µg/g still under quality standardsKeywords: Dumai Sea Western Waters, Sediments, Heavy Metal Pb and Cd

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. Physical properties of electron beam evaporated CdTe and CdTe:Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Punitha, K. [Department of Physics, Alagappa University, Karaikudi 630004 (India); Sivakumar, R., E-mail: krsivakumar1979@yahoo.com [Directorate of Distance Education, Alagappa University, Karaikudi 630004 (India); Sanjeeviraja, C. [Department of Physics, Alagappa Chettiar College of Engineering and Technology, Karaikudi 630004 (India); Sathe, Vasant; Ganesan, V. [UGC-DAE Consortium for Scientific Research, Indore 452001 (India)

    2014-12-07

    In this paper, we report on physical properties of pure and Cu doped cadmium telluride (CdTe) films deposited onto corning 7059 microscopic glass substrates by electron beam evaporation technique. X-ray diffraction study showed that all the deposited films belong to amorphous nature. The average transmittance of the films is varied between 77% and 90%. The optical energy band gap of pure CdTe film is 1.57 eV and it decreased to 1.47 eV upon 4 wt. % of Cu addition, which may be due to the extension of localized states in the band structure. The refractive index of the films was calculated using Swanepoel method. It was observed that the dispersion data obeyed the single oscillator of the Wemple-Didomenico model, from which the dispersion energy (E{sub d}) parameters, dielectric constants, plasma frequency, and oscillator energy (E{sub o}) of CdTe and CdTe:Cu films were calculated and discussed in detail with the light of possible mechanisms underlying the phenomena. The variation in intensity of photoluminescence band edge emission peak observed at 820 nm with Cu dopant is due to the change in surface state density. The observed trigonal lattice of Te peaks in the micro-Raman spectra confirms the p-type conductive nature of films, which was further corroborated by the Hall effect measurement. The lowest resistivity of 6.61 × 10{sup 4} Ω cm was obtained for the CdTe:Cu (3 wt. %) film.

  5. Characterization of CdS/CdTe and CdS/CuInSe2 thin film solar cells

    Science.gov (United States)

    Cheng, L. J.; Nguyen, T. T.; Shyu, C. M.; Basol, B. M.; Yoo, H. I.

    1984-01-01

    A study on low cost polycrystalline thin film CdS/CdTe and CdS/CuInSe2 solar cells using measurements of spectral response and capacitance-voltage-frequency relationships was performed. Because of high concentrations of localized levels in the energy gap existing in materials and at interfaces, the redistribution of charge among the levels due to illumination plays an important role in the collection of light-generated current in these cells. The results illustrate some related phenomena observed in these cells.

  6. Pb, Cu botanogeochemical anomalies and toxic effects on plant cells in Pb-Zn (Sn) ore fields, Northeast Guangxi Autonomous Region, China

    Institute of Scientific and Technical Information of China (English)

    SONG Ci'an; LEI Liangqi; YANG Qijun

    2007-01-01

    In the Lingchuan-Daoping and Xinglu Pb-Zn ore fields in northern and eastern Guangxi Autonomous Region, Pb, Cu botanogeochemical anomalies may be ascribed to the excessive amounts of Pb and Cu taken up by the root system of plants, such as China fir (Cunninghamia lanceolata Lamb. Hook), mason pine (Pinus massoniana Lamb.) and bracken fern (Pteridium aquilinum var. latiusculum). Under transmission electron microscope (TEM), the excess Pb, Cu in the leaf cells of the plants are present as high electron-density substances, which were precipitated in the leaf cells, causing phytotoxic effects by deforming and injuring cellular tissues. The sorts of toxic elements accumulating in the leaf cells are consistent with those of the botanogeochemically anomalous elements in the polluted soil where the plants grow. In addition, the plants may also be capable of resisting the invasion of excess Cu (and Pb) .

  7. Properties and Structure of the F-doped (Bi, Pb)-Sr-Ca-Cu-O Superconductor

    Institute of Scientific and Technical Information of China (English)

    高孝恢; 王小刚; 蒋淑芬; 李洁; 高赛; 郑国栋

    1994-01-01

    By using TEM, XPS, IR, position annihilation and differential specific heat measurements, the properties and structure of the F-doped (Bi, Pb)-Sr-Ca-Cu-O superconductor have been studied. The results show that the fluorine atoms are homogeneously distributed in superconducting phase and substituted for the oxygen atoms at O(2) crystallographic sites; the Pb-F and Cu-F bonds are formed. F-doping results in the variance of the incommensurate modulation structure, the increase of the point defects and chemical pressure, the enhancement of flux pinning effect and the change of the electronic structure and chemical bond, and greatly improves superconductive properties of the 2223 phase (Bi, Pb)-Sr-Ca-Cu-O.

  8. Behavior and influence of Pb and Bi in Ag-Cu-Zn brazing alloy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The effects of trace content of Pb and Bi elements on the spreading property and the strength of brazed joints of Ag-Cu-Zn filler metal have been studied. The results show that Pb has little effect on both above properties, and Bi has remarkable influence on the spreading property but little effect on the strength of brazed joint. Pb and Bi dissolve into the Ag-Cu-Zn matrix and will melt and gather at lower temperature when that alloy is being heated. Therefore a liquid forms on the surface of the Ag-Cu-Zn alloy and overlays the melting alloy, then keeps the filler metal away from the materials being joined, and so decreases the spreading property.

  9. Pb and Cd on growth, leaf ultrastructure and essential oil yield mint (Mentha arvensis L.

    Directory of Open Access Journals (Sweden)

    Caroline Nery Jezler

    2015-03-01

    Full Text Available Contamination of medicinal plants with heavy metals as Pb and Cd can affect the growth and the essential oil production of the plants and represent a risk to those who consume as medicine. This study aimed to evaluate the effects of absorption and localization of Pb and Cd on growth, ultrastructural aspects of leaves and essential oil yield and composition of Mentha arvensis, applied on the soil with increasing concentrations (8, 16, 32, 64 and 128mg kg-1. There was a differential absorption of Pb and Cd by M. arvensis mainly concentrated in the roots. Pb was found in small amounts in the leaves while Cd largely exceeded the safety limit without symptoms of toxicity. The ultrastructural analysis revealed the metal accumulation on vesicles surrounding the mitochondria and the presence of electron dense deposits surrounding the mitochondria, nucleus and chloroplasts. Little changes caused by Pb and Cd application were not enough to affect the growth and essential oil yield and composition of M. arvensis

  10. Effects of Cd2+ and Pb2+ on the substrate biofilms in the integrated vertical-flow constructed wetland

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jinlian; CHENG Shuiping; HE Feng; LIANG Wei; WU Zhenbin

    2008-01-01

    The effects of single Cd2+ and Pb2+ and combined Cd2+ and Pb2+ on dehydrogenase activity and polysaccharide content of the substrate biofilms in the integrated vertical-flow constructed wetland (IVCW) were studied. Dehydrogenase activities decreased linearly with the increasing concentrations of Cd2+ and Pb2+ at different times (6, 24, 72, and 120 h). The activities at both 6 and 24 h were significantly higher than that at 72 and 120 h in the case of single and combined treatments. The single Cd2+ and Pb2+ treatments significantly inhibited dehydrogenase activities at concentrations in excess of 20 μmol/L Cd2+ (equal to 2.24 mg/L Cd2+) and 80 μmol/L Pb2+ (equal to 16.56 mg/L Pb2+), respectively. The inhibitory effect of Cd2+ was much greater than that of Pb2+. At the same time, the combined treatment of Cd2+ and Pb2+ significantly inhibited dehydrogenase activities at all five concentrations studied and the lowest combined concentration was 1.25 μmol/L Cd2+ and 5 μmol/L Pb2+ (equal to 0.14 mg/L Cd2+ and 1.04 mg/L Pb2+). A synergistic effect of Cd2+ and Pb2+ was observed. On the other hand, polysaccharide contents varied unpredictably with the increasing concentrations of Cd2+ and Pb2+ and extended experimental time. There were no significant statistical differences within the range of concentration and time studied, whether singly or in combination. These results implied that the effects of heavy metals on biofilms should be a concern for the operation and maintenance of constructed wetlands.

  11. APPLICATION OF THE ANNEXATION PRINCIPLE TO THE STUDYOF THERMODYNAMIC PROPERTIES OF TERNARY METALLICMELTS Cd-Pb-Sb

    Institute of Scientific and Technical Information of China (English)

    J. Zhang

    2001-01-01

    Based on the phase diagrams, measured activities and the annexation principle, the calculating models of mass action concentrations for Cd-Pb, Pb-Sb and Cd-Sb binary as well as Cd-Pb-Sb ternary metallic melts have been formulated. The results of calculation both agree with practice and obey the mass action law. This in turn testifies that the models formulated can reflect the structural reality of corresponding melts and the annexation principle is applicable to these melts.``

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

    Science.gov (United States)

    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. PbS/CdS量子点的制备及光电性能研究%Study of preparation and photoelectric property of PbS/CdS quantum dots

    Institute of Scientific and Technical Information of China (English)

    靳斌斌; 陈丹; 王坤华

    2016-01-01

    利用简单的连续离子沉积反应(SILAR)将PbS和CdS量子点(QDs)沉积到TiO2表面上.通过与仅沉积PbS量子点的敏化太阳电池对比,发现PbS/CdS和CdS/pbS量子点提高了电池的光电性能.通过改变PbS和CdS量子点的沉积顺序来研究量子点结构对电池的影响,发现这两种量子点结构中性能优越的是PbS/CdS,推测这种量子点的能带结构可能更有利于电子的注入和空穴的再生.

  14. Speciation of Cd and Pb in dust emitted from sinter plant.

    Science.gov (United States)

    Sammut, M L; Noack, Y; Rose, J; Hazemann, J L; Proux, O; Depoux, M; Ziebel, A; Fiani, E

    2010-01-01

    Many studies have provided evidence of the impact of heavy metals in atmospheric emission. Sinter plants represent the first step in steel production, and are important emitters of Cd and Pb. The toxicity of these two metals depends above all on their speciation. Particles collected before and after the filtration system were analysed to determine the Cd- and Pb-bearing phases, using analytical tools such as XRF, EXAFS or ICP-AES and chemical leaching (sequential extractions adapted to steel dusts). Results show that Pb is associated with carbonate and Cd with chloride. These two types of speciation lead to high solubility under common environmental conditions, which may produce impacts on the environment and health.

  15. Pb(II) and Cd(II) removal from aqueous solutions by olive cake

    Energy Technology Data Exchange (ETDEWEB)

    Doyurum, Sabriye [Department of Chemistry, Faculty of Arts and Sciences, Celal Bayar University, Manisa 45140 (Turkey)]. E-mail: sabriyedoyurum@yahoo.com; Celik, Ali [Department of Chemistry, Faculty of Arts and Sciences, Celal Bayar University, Manisa 45140 (Turkey)

    2006-11-02

    The removal of heavy metals from wastewater using olive cake as an adsorbent was investigated. The effect of the contact time, pH, temperature, and concentration of adsorbate on adsorption performance of olive cake for Pb(II) and Cd(II) ions were examined by batch method. Adsorption of Pb(II) and Cd(II) in aqueous solution onto olive cake was studied in single component. After establishing the optimum conditions, elution of these ions from the adsorbent surface was also examined. The optimum sorption conditions were determined for two elements. Maximum desorption of the Pb(II) and Cd(II) ions were found to be 95.92 and 53.97% by 0.5 M HNO{sub 3} and 0.2 M HCl, respectively. The morphological analysis of the olive cake was performed by the scanning electron microscopy (SEM)

  16. Pb(II) and Cd(II) removal from aqueous solutions by olive cake.

    Science.gov (United States)

    Doyurum, Sabriye; Celik, Ali

    2006-11-02

    The removal of heavy metals from wastewater using olive cake as an adsorbent was investigated. The effect of the contact time, pH, temperature, and concentration of adsorbate on adsorption performance of olive cake for Pb(II) and Cd(II) ions were examined by batch method. Adsorption of Pb(II) and Cd(II) in aqueous solution onto olive cake was studied in single component. After establishing the optimum conditions, elution of these ions from the adsorbent surface was also examined. The optimum sorption conditions were determined for two elements. Maximum desorption of the Pb(II) and Cd(II) ions were found to be 95.92 and 53.97% by 0.5M HNO(3) and 0.2M HCl, respectively. The morphological analysis of the olive cake was performed by the scanning electron microscopy (SEM).

  17. Chalcophile elements Hg, Cd, Pb, As in Lake Umbozero, Murmansk Region, Russia

    DEFF Research Database (Denmark)

    Dauvalter, V.A.; Kashulin, N.A.; Lehto, J.;

    2009-01-01

    to higher concentrations of heavy metals in upper layers of sediments as compared to deeper layers. Among heavy metals, the highest factors of contamination were found for Cd and Pb. Pollution of the lake by chalcophile elements has also resulted in their accumulation in organs and tissues of whitefish...... is affected by emissions and effluents from mining and metallurgical enterprises of the Murmansk Region, as well as air pollution of a global character. Surface and near-bottom maxima were found in the distributions of Pb and Cd in the water column. These two maxima appear to be associated with the cyclical...... growth of phytoplankton in surface water layers and with sedimentation of lifeless organisms and suspended particles in near-bottom layers. Average concentrations of Pb and Cd in the water column were more than the average value for water of lakes of the taiga zone. Pollution of Lake Umbozero led...

  18. Simultaneous recovery of heavy metals (Pb, Cd, Zn from diluted solutions by electroextraction technique

    Directory of Open Access Journals (Sweden)

    Smara A.

    2013-04-01

    Full Text Available Cadmium is mainly used in galvanoplasty and stabilisation of plastic materials. It accumulates continuously in soils. The analysis of soil samples gave concrete evidence of increase of concentration of this element during the past centunary [1]. Furthermore Cd and Pb attack selectively the kidneys and the liver with enzymatic troubles. The work has enabaled to put into evidence the contribution of the presence of resin to the conventional electrodialysis process. The optimal conditions for the elimination of Cd++, Zn++ and Pb++ ions were determined. These included influence of resin, imposed current density, flow rate of the feeding solution (diluat, different supporting electrolytes used during the electroextraction (HNO3, HCl and H2SO4 and concentration of the solution to be treated [2-3-4]. Furthermore the competition between the electroextraction of the metallic cations Cd++, Zn++and Pb++ was investigated for different mixtures.

  19. UV-Induced Anisotropy In CdBr2-CdBr2: Cu Nanostructures

    Directory of Open Access Journals (Sweden)

    El-Naggar A. M.

    2015-09-01

    Full Text Available We have found an occurrence of anisotropy in the nanostructure CdBr2-CdBr2: Cu nanocrystalline films. The film thickness was varied from 4 nm up to 80 nm. The films were prepared by successive deposition of the novel layers onto the basic nanocrystals. The detection of anisotropy was performed by occurrence of anisotropy in the polarized light at 633 nm He-Ne laser wavelength. The occurrence of anisotropy was substantially dependent on the film thickness and the photoinduced power density. Possible mechanisms of the observed phenomena are discussed.

  20. Speciation and mobility of volatile heavy metals (Cd, Pb, and Tl) in fly ashes.

    Science.gov (United States)

    Świetlik, Ryszard; Trojanowska, Marzena; Karbowska, Bożena; Zembrzuski, Włodzimierz

    2016-11-01

    Speciation of volatile metals Cd, Pb, and Tl in fly ashes (FAs) produced from burning of hard coal in stocker-fired boilers (SFBs) was studied. Two grain fractions of fly ash collected in a multicyclone and battery cyclone of the systems of dust separation from three SFB units operating in various urban heating plants were analyzed. The characteristic feature of speciation of the three metals was a large share of labile fractions: Cd (av. 46.1 %), Pb (av. 39.8 %), and Tl (av. 21.6 %). The fraction which most clearly reflected the different chemical properties of the investigated metals was the oxidizable fraction: F(4)-Cd-0 %, F(4)-Pb-av. 10.0 %, and F(4)-Tl-av. 30.2 %. The importance of condensation of the volatile metal species on FA particles for shaping speciation of these metals was characterized using the normalized enrichment factor (NEF): Pb (2.3 ± 0.8) > Tl (1.8 ± 0.9) ≈ Cd (1.7 ± 0.6). Speciation of heavy metals may also be important economically, because the level of mobility coefficients (K Cd = 0.46, K Pb = 0.40, and K Tl = 0.22) in the case of fly ashes considerably enriched with toxic metals (Cd 4.8 ± 3.4 mg/kg, Pb 293 ± 210 mg/kg, and Tl 6.3 ± 4.5 mg/kg) may limit their utilization range.

  1. Chemical bath deposition of CdS thin films doped with Zn and Cu

    Indian Academy of Sciences (India)

    A I Oliva; J E Corona; R Patiño; A I Oliva-Avilés

    2014-04-01

    Zn- and Cu-doped CdS thin films were deposited onto glass substrates by the chemical bath technique. ZnCl2 and CuCl2 were incorporated as dopant agents into the conventional CdS chemical bath in order to promote the CdS doping process. The effect of the deposition time and the doping concentration on the physical properties of CdS films were investigated. The morphology, thickness, bandgap energy, crystalline structure and elemental composition of Zn- and Cu-doped CdS films were investigated and compared to the undoped CdS films properties. Both Zn- and Cu-doped CdS films presented a cubic crystalline structure with (1 1 1) as the preferential orientation. Lower values of the bandgap energy were observed for the doped CdS films as compared to those of the undoped CdS films. Zn-doped CdS films presented higher thickness and roughness values than those of Cu-doped CdS films. From the photoluminescence results, it is suggested that the inclusion of Zn and Cu into CdS crystalline structure promotes the formation of acceptor levels above the CdS valence band, resulting in lower bandgap energy values for the doped CdS films.

  2. Interation of Pb and Cd in Soil—Water—Plant System and Its Mechanism:I.Pb—Cd Interatction in Red SoilPlant System

    Institute of Scientific and Technical Information of China (English)

    ZHENGCHUNRONG; CHENHUAIMAN

    1996-01-01

    A study on the effect of Pb-Cd interaction on plant growth and on the chemistry of elements in plants was conducted under greenhouse condition with red soil-wetland rice system in different growth stage.The results showed that Pb-Cd interactions on growth and metal uptake varied with different growth stages and chemical compounds added .The plant height and the root weght were markedly affected by Pb-Cd interication in the young stage but not in the ripening stage of rice at the treatments of PbCl2 and CdCl2 added.However,the weight of rice straw in the ripening stage was significantly affected by Pb-Cd interaction with the treatments of Pb(OAc)2 and CdCl2.The chemistry of elements in plants also depended on Pb-Cd interaction in varying degrees on account of different plant parts and growth stage.It seems that Pb-Cd interaction occurred not only in roots but also in other parts of wetland rice.

  3. Spatial distribution of Cd and Cu in soils in Shenyang Zhangshi Irrigation Area (SZIA), China

    Institute of Scientific and Technical Information of China (English)

    Lina SUN; Xiao-e YANG; Wen-qing WANG; Li MA; Su CHEN

    2008-01-01

    Heavy metal contamination of soils, derived from sewage irrigation, mining and inappropriate utilization of various agrochemicals and pesticides, and so on, has been of wide concern in the last several decades. The Shenyang Zhangshi Irrigation Area (SZIA) in China is a representative area of heavy metal contamination of soils resulting from sewage irrigation for about 30 years. This study investigated the spatial distribution and temporal variation of soil cadmium (Cd) and copper (Cu) contamination in the SZIA. The soil samples were collected from the SZIA in 1990 and 2004; Cd and Cu in soils was analyzed and then the spatial distribution and temporal variation of Cd and Cu in soils were modeled using Kriging methods. The results show that long-term sewage irrigation had caused serious Cd and Cu contamination in soils. The mean and the maximum of soil Cd are markedly higher than the levels in second grade standard soil (LSGSS) in China, and the maximum of soil Cu is close to the LSGSS in China in 2004 and is more than the LSGSS in China in 1990. The contamination magnitude of soil Cd and the soil extent of Cd con- tamination had evidently increased since sewage irrigation ceased in 1992. The contamination magnitude of soil Cu and the soil extent of Cu contamination had evidently increased in topsoil, but obviously decresed in subsoil. The soil contamination of Cd and Cu was mainly related to Cd and Cu reactivation of contaminated sediments in Shenyang Xi River and the import of Cd and Cu during irrigation. The eluviation of Cd and Cu in contaminated topsoil with rainfall and irrigation water was another factor of temporal-spatial variability of Cd and Cu contamination in soils.

  4. [Expression of adhesion molecules on CD34+ cells of BM and PB stem cell samples during high-dose chemotherapy combined with transplantation of autologous PB stem cells].

    Science.gov (United States)

    Liu, Peng; Han, Xiao-Hong; Shi, Yuan-Kai; He, Xiao-Hui; Yang, Cheng; Ai, Bin

    2004-12-01

    This study was aimed to investigate the expressions of adhesion molecules such as CD54, CD49d and CD62L by CD34(+) cells sampled from different stages of bone marrow (BM) and peripheral blood (PB) before/after G-CSF mobilization and after transplantation through the direct labeling with three colour-immunofluorescence and flow cytometry, and to explore the differences in expression of adhesion molecules on CD34(+) cells from different origins and their clinical significance. Mononuclear cells collected from BM and PB before mobilization, after collection of stem cells and hematopoietic recostruction of BM at the end of transplantation were marked with CD54-FITC, CD49d-FITC and CD62L-FITC separately, as well as CD34-PE and CD45PerCE. 3-color fluorescene analysis was carried out by FACS. The expression differences of CD34(+) and adhesion molecules between BM and APBSC were compared. The results showed that expression differences of CD54, CD49d and cd62Lon CD34(+) cells belore mobilization, after collection and reconstraction of transplantation were not statiscally significant, the difference of CD54, CD49d and CD62L on CD34(+) between 1st and 2nd collections of hematopoietic stem cells also were not statiscally significant. In the collected APBSC, the expression level of CD34(+) CD49d(+) was significantly lower than those in BM before mobilization (P = 0.001). It is concluded that the method of chemotherapy combined with G-CSF mobilization can down-regulate CD49d expression in BM CD34(+) cells, thus can mobilize and move theirs into peripheral blood. After the reconstitution by transplantation, the expression of CD49d on CD34(+) cells tends to normal, the clinical significance needs to be elucidated by accumulation of much more cases.

  5. Micronucleus Test, Nuclear Abnormalities and Accumulation of Cu and Cd on Gambusia affinis (Baird & Girard, 1853)

    OpenAIRE

    Güner, Utku; Dilek, Fulya; Muranlı, Gökalp

    2011-01-01

    In the present work the induction of micronuclei (MNi) and nuclear abnormalities (NAs) in erythrocytes and Cu and Cd accumulation in whole body of Gambusia affinis were studied. Fish were exposed to two different Cu and Cd concentrations, 0.1 ppm and 1 ppm, for 1 and 2 weeks periods and to Cu-Cd combination (0.1 ppm Cu + 0.1 ppm Cd) for 2 weeks period using a semi-static renewal system. Micronucleus and nuclear abnormality analysis were carried out on peripheral blood erythrocytes. When fish...

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

    Science.gov (United States)

    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 pHconcrete 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.

  7. Adsorption characteristics of Cu(II) and Pb(II) onto expanded perlite from aqueous solution.

    Science.gov (United States)

    Sari, Ahmet; Tuzen, Mustafa; Citak, Demirhan; Soylak, Mustafa

    2007-09-01

    The adsorption characteristics of Cu(II) and Pb(II) onto expanded perlite (EP) from aqueous solution were investigated with respect to the changes in pH of solution, adsorbent dosage, contact time and temperature of solution. For the adsorption of both metal ions, the Langmuir isotherm model fitted to equilibrium data better than the Freundlich isotherm model. Using the Langmuir model equation, the monolayer adsorption capacity of EP was found to be 8.62 and 13.39 mg/g for Cu(II) and Pb(II) ions, respectively. Dubinin-Radushkevich (D-R) isotherm model was also applied to the equilibrium data and the mean free energies of adsorption were found as 10.82 kJ/mol for Cu(II) and 9.12 kJ/mol for Pb(II) indicating that the adsorption of both metal ions onto EP was taken place by chemical ion-exchange. Thermodynamic functions, the change of free energy (DeltaG degrees ), enthalpy (DeltaH degrees ) and entropy (DeltaS degrees ) of adsorption were also calculated for each metal ions. These parameters showed that the adsorption of Cu(II) and Pb(II) ions onto EP was feasible, spontaneous and exothermic at 20-50 degrees C. Experimental data were also evaluated in terms of kinetic characteristics of adsorption and it was found that adsorption process for both metal ions followed well pseudo-second-order kinetics.

  8. Sulfur Isotopes Geochemistry of the Nage Cu-Pb Polymetallic Deposit, Southeast Guizhou Province, China

    Institute of Scientific and Technical Information of China (English)

    LONG Xuan-lin; ZHOU Jia-xi; HUANG Zhi-long; WANG Jing-song; YANG De-zhi; FAN Liang-wu; BAO Guang-ping; LIU Yong-kun

    2009-01-01

    @@ The Nage Cu-Pb polymetallic deposit is located in the transitional zone of the Yangtze craton and cathaysia, that is the southwest of Jiangnan orogenic belt. The mainly strata are Wentong formation of Mesoproterozoic Sibo group and the Jialu formation (Qbj) , Wuye formation (Qbw) , Fanzhao formation (Qbf) and Gongdong formation (Qbg) of the Neoproterozoic Qingbaikou System Xiajiang group.

  9. [Leaching behavior of Pb, Cd and Zn from soil stabilized by lime stabilized sludge].

    Science.gov (United States)

    Li, Xiang; Song, Yun; Liu, Yong-Bing

    2014-05-01

    Stabilization of Pb, Cd and Zn spiked soil by using lime-stabilized sewage sludge( LSS) as amendment was investigated in this study, and the effectiveness was evaluated by using leaching tests ( TCLP, SPLP and de-ionized water) and modified BCR sequential extraction procedure. The results of TCLP indicated that the concentrations of heavy metals in TCLP leachate reduced significantly with the increase of the mass percentage of the LSS and the leaching reduction rates were as high as 99. 54% for Zn, 99. 60% for Pb, 99. 85% for Cd at 40% of LSS addition. When evaluated by SPLP and de-ionized water leaching method, the concentrations of Zn and Pb in leachate decreased obviously at 10% and 20% of LSS additions, but subsequently increased at 30% and 40% because of redissolution of Zn and Pb at strong base condition. After pH value of LLS-stabilized soil was adjusted by ferrous sulfate and phosphoric acid for recovering soil plantation function, the pH value of the soil decreased effectively, in the meantime promoting the stabilization effectiveness of Pb and Zn. The BCR test revealed that compared with the spiked soil exchangeable proportion of Zn, Pb, Cd in the soil and the soils adjusted by ferrous sulfate obviously declined, which implied the migration for Pb, Cd and Zn of contaminated soil could be confined. This study results show that municipal LSS can be reused in the stabilization of heavy metal contaminated soils and physical and chemical properties of LLS-stabilized soil are improved for plantation.

  10. A surface complexation and ion exchange model of Pb and Cd competitive sorption on natural soils

    Science.gov (United States)

    Serrano, Susana; O'Day, Peggy A.; Vlassopoulos, Dimitri; García-González, Maria Teresa; Garrido, Fernando

    2009-02-01

    The bioavailability and fate of heavy metals in the environment are often controlled by sorption reactions on the reactive surfaces of soil minerals. We have developed a non-electrostatic equilibrium model (NEM) with both surface complexation and ion exchange reactions to describe the sorption of Pb and Cd in single- and binary-metal systems over a range of pH and metal concentration. Mineralogical and exchange properties of three different acidic soils were used to constrain surface reactions in the model and to estimate surface densities for sorption sites, rather than treating them as adjustable parameters. Soil heterogeneity was modeled with >FeOH and >SOH functional groups, representing Fe- and Al-oxyhydroxide minerals and phyllosilicate clay mineral edge sites, and two ion exchange sites (X - and Y -), representing clay mineral exchange. An optimization process was carried out using the entire experimental sorption data set to determine the binding constants for Pb and Cd surface complexation and ion exchange reactions. Modeling results showed that the adsorption of Pb and Cd was distributed between ion exchange sites at low pH values and specific adsorption sites at higher pH values, mainly associated with >FeOH sites. Modeling results confirmed the greater tendency of Cd to be retained on exchange sites compared to Pb, which had a higher affinity than Cd for specific adsorption on >FeOH sites. Lead retention on >FeOH occurred at lower pH than for Cd, suggesting that Pb sorbs to surface hydroxyl groups at pH values at which Cd interacts only with exchange sites. The results from the binary system (both Pb and Cd present) showed that Cd retained in >FeOH sites decreased significantly in the presence of Pb, while the occupancy of Pb in these sites did not change in the presence of Cd. As a consequence of this competition, Cd was shifted to ion exchange sites, where it competes with Pb and possibly Ca (from the background electrolyte). Sorption on >SOH

  11. Differential tolerance of Agrostis tenuis populations growing at two mine soils to Cu, Zn, and Pb

    Energy Technology Data Exchange (ETDEWEB)

    Karataglis, S.S.

    1980-01-01

    The Cu, Zn and Pb tolerance of Agrostis tenuis Sibth. populations found in the area of two mines in England as well as in uncontaminated areas were studied by determining the effect of these metals on the rooting of tillers. The populations proved tolerant to the particular metals present in high quantities in the soil of their original habitats as compared to the populations collected from uncontaminated soil. The populations of the Trelogan mine were tolerant only to Zn and not to Cu and Pb. On the contrary, the populations in the mine of Parys Mountain were highly tolerant to all these metals. A linear correlation in the index of tolerance between Zn and Pb in both mines was found suggesting the possibility of a physiological association of the tolerance mechanisms to these two elements.

  12. Cd4Cu7As, the first representative of a fully ordered, orthorhombically distorted MgCu2 Laves phase.

    Science.gov (United States)

    Osters, Oliver; Nilges, Tom; Schöneich, Michael; Schmidt, Peer; Rothballer, Jan; Pielnhofer, Florian; Weihrich, Richard

    2012-08-06

    The ternary Laves phase Cd(4)Cu(7)As is the first intermetallic compound in the system Cu-Cd-As and a representative of a new substitution variant for Laves phases. It crystallizes orthorhombically in the space group Pnnm (No. 58) with lattice parameters a = 9.8833(7) Å; b = 7.1251(3) Å; c = 5.0895(4) Å. All sites are fully occupied within the standard deviations. The structure can be described as typical Laves phase, where Cu and As are forming vertex-linked tetrahedra and Cd adopts the structure motive of a distorted diamond network. Cd(4)Cu(7)As was prepared from stoichiometric mixtures of the elements in a solid state reaction at 1000 °C. Magnetic measurements are showing a Pauli paramagnetic behavior. During our systematical investigations within the ternary phase triangle Cd-Cu-As the cubic C15-type Laves phase Cd(4)Cu(6.9(1))As(1.1(1)) was structurally characterized. It crystallizes cubic in the space group Fd3m with lattice parameter a = 7.0779(8) Å. Typically for quasi-binary Laves phases Cu and As are both occupying the 16c site. Chemical bonding, charge transfer and atomic properties of Cd(4)Cu(7)As were analyzed by band structure, ELF, and AIM calculations. On the basis of the general formula for Laves phases AB(2), Cd is slightly positively charged forming the A substructure, whereas Cu and As represent the negatively charged B substructure in both cases. The crystal structure distortion is thus related to local effects caused by Arsenic that exhibits a larger atomic volume (18 Å(3) compared to 13 Å(3) for Cu) and higher ionicity in bonding.

  13. Nanoscale morphology of multilayer PbTe/CdTe heterostructures and its effect on photoluminescence properties.

    Science.gov (United States)

    Karczewski, G; Szot, M; Kret, S; Kowalczyk, L; Chusnutdinow, S; Wojtowicz, T; Schreyeck, S; Brunner, K; Schumacher, C; Molenkamp, L W

    2015-03-27

    We study nanoscale morphology of PbTe/CdTe multilayer heterostuctures grown by molecular beam epitaxy on hybrid GaAs/CdTe (100) substrates. Nominally, the structures consist of 25 repetitions of subsequently deposited CdTe and PbTe layers with comparable thicknesses of 21 and 8 nm, respectively. However, the morphology of the resulting structures crucially depends on the growth temperature. The two-dimensional layered, superlattice-like character of the structures remains preserved only when grown at low substrate temperatures, such as 230 °C. The samples grown at the slightly elevated temperature of 270 °C undergo a morphological transformation to structures consisting of CdTe and PbTe pillars and columns oriented perpendicular to the substrate. Although the pillar-like objects are of various shapes and dimensions these structures exhibit exceptionally strong photoluminescence in the near infrared spectral region. At the higher growth temperature of 310 °C, PbTe and CdTe separate completely forming thick layers oriented longitudinally to the substrate plane. The observed topological transformations are driven by thermally activated atomic diffusion in the solid state phase. The solid state phase remains fully coherent during the processes. The observed topological transitions leading to the material separation in PbTe/CdTe system could be regarded as an analog of spinodal decomposition of an immiscible solid state solution and thus they can be qualitatively described by the Cahn-Hillard model as proposed by Groiss et al (2014 APL Mater. 2 012105).

  14. Comparison of serum Concentration of Se, Pb, Mg, Cu, Zn, between MS patients and healthy controls

    Science.gov (United States)

    Alizadeh, Anahita; Mehrpour, Omid; Nikkhah, Karim; Bayat, Golnaz; Espandani, Mahsa; Golzari, Alireza; Jarahi, Lida; Foroughipour, Mohsen

    2016-01-01

    Introduction Multiple Sclerosis (MS) is defined as one of the inflammatory autoimmune disorders and is common. Its exact etiology is unclear. There are some evidences on the role of environmental factors in susceptible genetics. The aim of this study is to evaluate the possible role of Selenium, Zinc, Copper, Lead and Magnesium metals in Multiple Sclerosis patients. Methods In the present analytical cross-sectional study, 56 individuals including 26 patients and 30 healthy controls were enrolled in the evaluation. The serum level of Se, Zn, Cu, Pb were quantified in graphite furnace conditions and flame conditions by utilizing an atomic absorption Perkin Elmer spectrophotometer 3030. The serum levels of Mg were measured by auto analyzer 1500 BT. The mean level of minerals (Zn, Pb, Cu, Mg, Se) in serum samples were compared in both cases and controls. The mean level of minerals (Zn, Pb, Cu, Mg, Se) in serum samples were compared in both cases and controls by using independent-samples t-test for normal distribution and Mann-Whitney U test as a non-parametric test. All statistical analyses were carried out using SPSS 11.0. Results As well as the Zn, Cu, and Se, there was no significant difference between MS patients and healthy individuals in Pb concentrations (p-value = 0.11, 0.14, 0.32, 0.20 respectively) but the level of Mg was significantly different (p= 0.001). Conclusion All serum concentrations of Zn, Pb, Se, Cu in both groups were in normal ranges and there was no difference in MS patients compared with the healthy group who were matched in genetics. Blood level of Mg was significantly lower in MS patients. But it should be noted that even with the low level of serum magnesium in MS patients, this value is still in the normal range. PMID:27757186

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

    Energy Technology Data Exchange (ETDEWEB)

    Weng, Ke-Chuan [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Wang, Y. K., E-mail: kant@ntnu.edu.tw [Center for General Education and Department of Physics, National Taiwan Normal University, Taipei 106, Taiwan (China)

    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. Evaluation of toxic trace metals Cd and Pb in Arabian Sea waters

    Digital Repository Service at National Institute of Oceanography (India)

    Sanzgiri, S.; Mesquita, A.; Kureishy, T.W.; SenGupta, R.

    . Depthwise profiles of both the metals have been examined and attempt has been made to correlate these with the general nutrient profiles of the region. Dissolved Pb is higher at surface and decreases deeper down while dissolved Cd shows elevated intermediate...

  17. Biosorption kinetics of Cd (II, Cr (III and Pb (II in aqueous solutions by olive stone

    Directory of Open Access Journals (Sweden)

    M. Calero

    2009-06-01

    Full Text Available A by-product from olive oil production, olive stone, was investigated for the removal of Cd (II, Cr (III and Pb (II from aqueous solutions. The kinetics of biosorption are studied, analyzing the effect of the initial concentration of metal and temperature. Pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models have been used to represent the kinetics of the process and obtain the main kinetic parameters. The results show that the pseudo-second order model is the one that best describes the biosorption of the three metal ions for all the range of experimental conditions investigated. For the three metal ions, the maximum biosoption capacity and the initial biosorption rate increase when the initial metal concentration rises. However, the kinetic constant decreases when the initial metal concentration increases. The temperature effect on biosorption capacity for Cd (II and Cr (III is less significant; however, for Pb (II the effect of temperature is more important, especially when temperature rises from 25 to 40ºC. The biosorption capacity at mmol/g of olive stone changes in the following order: Cr>Cd>Pb. Thus, for an initial concentration of 220 mg/ℓ, a maximum sorption capacity of 0.079 mmol/g for Cr (III, 0.065 mmol/g for Cd (II and 0.028 mmol/g for Pb (II has been obtained.

  18. The Adsorption and Desorption of Pb(2+) and Cd(2+) in Freeze-Thaw Treated Soils.

    Science.gov (United States)

    Li, Linhui; Ma, Jincai; Xu, Meng; Li, Xu; Tao, Jiahui; Wang, Guanzhu; Yu, Jitong; Guo, Ping

    2016-01-01

    Adsorption and desorption are important processes that influence the potential toxicity and bioavailability of heavy metals in soils. However, information regarding adsorption and desorption behavior of heavy metals in soils subjected to freeze-thaw cycles is poorly understood. In the current study, the effect of freeze-thaw cycles with different freezing temperature (-15, -25, -35°C) on soil properties was investigated. Then the adsorption and desorption behavior of Pb(2+) and Cd(2+) in freeze-thaw treated soils was studied. The adsorption amounts of Pb(2+) and Cd(2+) in freeze-thaw treated soils were smaller than those in unfrozen soils (p adsorption amounts of Pb(2+) and Cd(2+) in soils treated with lower freezing temperatures were higher than those in soils treated with higher freezing temperatures. Desorption percentages of Pb(2+) and Cd(2+) in unfrozen soils were smaller than those in freeze-thaw treated soils (p adsorption and desorption behavior of typical heavy metals in freeze-thaw treated soils located in seasonal frozen soils zone in northeast China.

  19. Responses of membrane protection enzyme system of tobacco leaves on Hg, Cd and Pb stresses in soil.

    Science.gov (United States)

    Yan, Chong Ling; Lin, Peng; Wang, Xiao Rong

    2002-09-01

    Pot experiment was used to study the responses of membrane protection enzyme system of tobacco leaves on Hg, Cd and Pb stresses in soil. The results showed that POD activity gradually increased with increasing concetrations of Hg, Cd and Pb. CAT and SOD activity gradually decreased under three heavy metals common existing and SOD variation curve showed unimodal curve under single or two elements existing with increase of concentration of Hg, Cd and Pb. The effects of Hg, Cd and Pb in soil: three elemets together > two elements together > single element only. The effects resulted in an imbalance--activated oxygen produce and scavenge and physiological biochemical process disorder. There was a synergistic action for the effect of Hg, Cd and Pb in soil on membrane protection enzyme system in tobacco leaves.

  20. Solution-phase synthesis of un-doped and Pb doped CdO films

    Science.gov (United States)

    Gülen, Y.; Sahin, B.; Bayansal, F.; Çetinkara, H. A.

    2014-04-01

    In this work, un-doped and Pb doped cadmium oxide (CdO) films were prepared for the first time on glass substrates by successive ionic layer adsorption and reaction (SILAR) technique. The crystal structure parameters such as average crystallite size and dislocation density were calculated from X-ray diffraction analysis. XRD analysis showed that the films have poly-crystalline structures with decent crystallinity levels. Surface morphology was found to be modified with various Pb doping concentrations. The diameters of the nanoparticles were calculated from the SEM. The optical properties of the prepared CdO films were characterized by ultraviolet-visible spectrophotometer. With the increase in Pb concantration from 0.5% to 2.5%, the optical absorption edge shifted towards shorter wavelengths which might be attributed to change in crystallite size.

  1. Investigation of Cu-poor and Cu-rich Cu(In,Ga)Se{sub 2}/CdS interfaces using hard X-ray photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ümsür, B., E-mail: buenyamin.uemsuer@helmholtz-berlin.de [Helmholtz-Zentrum-Berlin, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Calvet, W.; Höpfner, B.; Steigert, A.; Lauermann, I.; Gorgoi, M.; Prietzel, K.; Navirian, H.A.; Kaufmann, C.A.; Unold, T. [Helmholtz-Zentrum-Berlin, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Lux-Steiner, M. Ch. [Helmholtz-Zentrum-Berlin, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Freie Universität Berlin, Department of Physics, Arnimallee 14, D-14195 Berlin (Germany)

    2015-05-01

    Cu-poor and Cu-rich Cu(In,Ga)Se{sub 2} (CIGSe) absorbers were used as substrates for the chemical bath deposition of ultrathin CdS buffer layers in the thickness range of a few nanometers in order to make the CIGSe/CdS interface accessible by hard X-ray photo-emission spectroscopy. The composition of both, the absorber and the buffer layer as well as the energetics of the interface was investigated at room temperature and after heating the samples to elevated temperatures (200 °C, 300 °C and 400 °C). It was found that the amount of Cd after the heating treatment depends on the near surface composition of the CIGSe absorber. No Cd was detected on the Cu-poor surface after the 400 °C treatment due to its diffusion into the CIGSe layer. In contrast, Cd was still present on the Cu-rich surface after the same treatment at 400 °C. - Highlights: • Cd diffusion into Cu(In,Ga)Se{sub 2} (CIGSe) absorber is investigated. • Cu-poor and Cu-rich CIGSe samples are compared. • Cd diffusion into CIGSe is found to be dependent on the surface composition of CIGSe.

  2. Determination of Cd, Pb and As in sediments of the Sava River by electrothermal atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    SIMONA MURKO

    2010-01-01

    Full Text Available The applicability of nitric acid, palladium nitrate and a mixture of palladium and magnesium nitrate as matrix modifiers were estimated for the accurate and reproducible determination of cadmium (Cd, lead (Pb and arsenic (As in sediments of the Sava River by electrothermal atomic absorption spectrometry, ETAAS. Decomposition of the samples was done in a closed vessel microwave-assisted digestion system using nitric, hydrochloric and hydrofluoric acids, followed by the addition of boric acid to convert the fluorides into soluble complexes. The parameters for the determination of Cd, Pb and As in sediments were optimised for each individual element and for each matrix modifier. In addition, two sediment reference materials were also analysed. In determination of Cd and Pb, nitric acid was found to be the most appropriate matrix modifier. The accurate and reliable determination of Cd and Pb in sediments was possible also in the presence of boric acid. The use of a mixture of palladium and magnesium nitrate efficiently compensated for matrix effects and enabled the accurate and reliable determination of As in the sediments. Quantification of Cd and As was performed by calibration using acid matched standard solutions, while the standard addition method was applied for the quantification of Pb. The repeatability of the analytical procedure for the determination of Cd, Pb and As in sediments was ±5 % for Cd, ±4 % for Pb and ±2 % for As. The LOD values of the analytical procedure were found to be 0.05 mg/kg for Cd and 0.25 mg/kg for Pb and As, while the LOQ values were 0.16 mg/kg for Cd and 0.83 mg/kg for Pb and As. Finally, Cd, Pb and As were successfully determined in sediments of the Sava River in Slovenia.

  3. Accumulation dynamics and cellular locations of Pb, Zn and Cd in resident and transplanted Flavocetraria nivalis lichens near a former Pb-Zn mine

    DEFF Research Database (Denmark)

    Søndergaard, Jens

    2013-01-01

    Accumulation dynamics and cellular locations of lead (Pb), zinc (Zn) and cadmium (Cd) were studied in Flavocetraria nivalis lichens near the former Black Angel Pb-Zn Mine in West Greenland. Natural resident thalli were collected from four dust-contaminated sites near the mine. In addition, thalli...

  4. Stability Effect In Photoconducting Studies of Some Chemically Deposited CdS, (Cd-Pb)S and (Cd-Zn)S Films

    OpenAIRE

    2008-01-01

    Stability effects in photoconductivity (PC) rise and decay have been studied over a period of 2 years in thin films of (Cd-Pb)S:LiF, La/Pr and (Cd-Zn)S: LiF,La/Pr and have been found quite stable; however, those of CdS are not that stable. Results of annealing effect are also included, which present more stable values. XRD studies show prominent lines of base materials. Further, XRD and SEM studies show the particle sizes are in the nanometer range. Results of optical absorption sp...

  5. Assessment of Pb, Cd, Cr and Ag leaching from electronics waste using four extraction methods.

    Science.gov (United States)

    Keith, Ashley; Keesling, Kara; Fitzwater, Kendra K; Pichtel, John; Houy, Denise

    2008-12-01

    Heavy metals present in electronic components may leach upon disposal and therefore pose significant environmental hazards. The potential leaching of Pb, Cd, Cr and Ag from PC cathode ray tubes, printed circuit boards (PCBs), PC mice, TV remote controls, and mobile phones was assessed. After controlled crushing, each component was extracted using the Toxicity Characteristic Leaching Procedure (TCLP), EPA Method 1312 (SPLP), NEN 7371 (Dutch Environmental Agency), and DIN S4 (Germany). The TCLP consistently leached the greatest amounts of Pb from all components. The SPLP, NEN 7371 and DIN S4 extracted relatively small amounts of metals compared with the TCLP and were not considered effective as leaching tests for e-waste. The smallest size fraction (< 2 mm) of CRT glass and PCBs leached significantly (p < 0.05) highest Pb via the TCLP. A modified TCLP removed 50.9% more extractable Pb compared with the conventional procedure.

  6. Dual emission in asymmetric ``giant'' PbS/CdS/CdS core/shell/shell quantum dots

    Science.gov (United States)

    Zhao, Haiguang; Sirigu, Gianluca; Parisini, Andrea; Camellini, Andrea; Nicotra, Giuseppe; Rosei, Federico; Morandi, Vittorio; Zavelani-Rossi, Margherita; Vomiero, Alberto

    2016-02-01

    Semiconducting nanocrystals optically active in the infrared region of the electromagnetic spectrum enable exciting avenues in fundamental research and novel applications compatible with the infrared transparency windows of biosystems such as chemical and biological optical sensing, including nanoscale thermometry. In this context, quantum dots (QDs) with double color emission may represent ultra-accurate and self-calibrating nanosystems. We present the synthesis of giant core/shell/shell asymmetric QDs having a PbS/CdS zinc blende (Zb)/CdS wurtzite (Wz) structure with double color emission close to the near-infrared (NIR) region. We show that the double emission depends on the excitation condition and analyze the electron-hole distribution responsible for the independent and simultaneous radiative exciton recombination in the PbS core and in the CdS Wz shell, respectively. These results highlight the importance of the driving force leading to preferential crystal growth in asymmetric QDs, and provide a pathway for the rational control of the synthesis of double color emitting giant QDs, leading to the effective exploitation of visible/NIR transparency windows.Semiconducting nanocrystals optically active in the infrared region of the electromagnetic spectrum enable exciting avenues in fundamental research and novel applications compatible with the infrared transparency windows of biosystems such as chemical and biological optical sensing, including nanoscale thermometry. In this context, quantum dots (QDs) with double color emission may represent ultra-accurate and self-calibrating nanosystems. We present the synthesis of giant core/shell/shell asymmetric QDs having a PbS/CdS zinc blende (Zb)/CdS wurtzite (Wz) structure with double color emission close to the near-infrared (NIR) region. We show that the double emission depends on the excitation condition and analyze the electron-hole distribution responsible for the independent and simultaneous radiative exciton

  7. Assessment of the Bioavailability of Cu, Pb, and Zn through Petunia axillaris in Contaminated Soils

    Directory of Open Access Journals (Sweden)

    Lydia Bondareva

    2014-01-01

    Full Text Available Heavy metals are potentially toxic to human life and the environment. Metal toxicity depends on chemical associations in soils. For this reason, determining the chemical form of a metal in soils is important to evaluate its mobility and the potential accumulation. The aim of this examination is to evaluate the accumulation potential of Petunia x hybrida as a flower crop for three metals, namely, copper (Cu, lead (Pb, and nickel (Ni. Trace metals (Zn, Cu, and Pb in the soils were partitioned by a sequential extraction procedure into H2O extractable (F1, 1 M CH3COONa extractable (F2. Chemical fractionation showed that F1 and F2 fraction of the metals were near 1% and residue was the dominant form for Zn, Cu, and Pb in all samples. Using fluorescence method allowed us to estimate condition of the plants by adding metals. As result of plant and soil analysis, we can conclude that Petunia has Cu, Zn, and Ni tolerance and accumulation. Therefore, Petunia has the potential to serve as a model species for developing herbaceous, ornamental plants for phytoremediation.

  8. Cu{sub 2}S as ohmic back contact for CdTe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Türck, Johannes; Siol, Sebastian; Mayer, Thomas; Klein, Andreas; Jaegermann, Wolfram, E-mail: jaegermann@surface.tu-darmstadt.de

    2015-05-01

    We prepared a back contact for CdTe solar cells with Cu{sub 2}S as primary contact. Cu{sub 2}S was evaporated on CdCl{sub 2} treated CdTe solar cells in superstrate configuration. The CdTe and CdS layers were deposited by Closed Space Sublimation. Direct interface studies with X-ray photoelectron spectroscopy have revealed a strongly reactive interface between CdTe and Cu{sub 2}S. A valence band offset of 0.4-0.6 eV has been determined. The performance of solar cells with Cu{sub 2}S back contacts was studied in comparison to cells with an Au contact that deposited onto a CdCl{sub 2}-treated CdTe surface that was chemically etched using a nitric-phosphoric etch. The solar cells were analyzed by current-voltage curves and external quantum efficiency measurements. After several post deposition annealing steps, 13% efficiency was reached with the Cu{sub 2}S back contact, which was significantly higher than the ones obtained for the NP-etched back contacts. - Highlights: • A new back contact for CdTe solar out of Cu{sub 2}S has been tested. • With a direct interface experiment the valence band offset was determined. • Post deposition heat treatment has been carried out for the solar cells. • 13% efficiency has been reached with the Cu{sub 2}S back contact.

  9. Self-organization of Pb thin films on Cu(111) induced by quantum size effects

    Science.gov (United States)

    Dil, J. H.; Kim, J. W.; Gokhale, S.; Tallarida, M.; Horn, K.

    2004-07-01

    Electron confinement in thin films of Pb on Cu(111) leads to the formation of quantum well states, formed out of the upper valence band of Pb. Their evolution as a function of film thickness is characterized in angle-resolved photoemission and can be interpreted in terms of a straightforward quantum well model. This permits an identification of film growth mode at low temperatures. Bringing the films into thermal equilibrium by annealing induces strong changes in the spectra. Their interpretation demonstrates that specific “magic” layers are preferred because of total energy minimization induced by the arrangement of quantum well states with respect to the Fermi level.

  10. Heat treatment effects in Cu2S-CdS heterojunction photovoltaic cells

    Science.gov (United States)

    Fahrenbruch, A. L.; Bube, R. H.

    1974-01-01

    The dependence of the short-circuit current on photon energy, temperature, and the state of optical degradation (or enhancement) is determined in a study of the photovoltaic properties of Cu2S-CdS single-crystal heterojunctions. A coherent formulation is proposed for the relationship between enhancement and optical degradation and for their effects on the transport of a short-circuit photoexcited current and dark forward-bias current in a photovoltaic cell. Optical degradation in a Cu2S-CdS cell is shown to be identical to the optical degradation of lifetime in a homogeneous CdS:Cd:Cu crystal.

  11. Electrochemiluminescent detection of Pb2+ by graphene/gold nanoparticles and CdSe quantum dots

    Science.gov (United States)

    Lu, Liping; Guo, Linqing; Li, Jiao; Kang, Tianfang; Cheng, Shuiyuan

    2016-12-01

    A highly sensitive electrochemiluminescent detection method for lead ions (Pb(II)) was fabricated based on the distance-dependent quenching of the electrochemiluminescence from CdSe quantum dots by nanocomposites of graphene and gold nanoparticles. Graphene/gold nanoparticles were electrochemically deposited onto a glassy carbon electrode through the constant potential method. Thiol-labeled DNA was then assembled on the surface of the electrode via gold-sulfur bonding, following which the amino-labeled terminal of the DNA was linked to carboxylated CdSe quantum dots by the formation of amide bonds. The 27-base aptamer was designed with two different domains: the immobilization and detection sequences. The immobilization sequence was paired with 12 complementary bases and immobilized on the gold electrode; the single-stranded detection sequence, rich in G bases, formed a G-quadruplex (G4) structure in the presence of Pb2+. The formation of G4 shortens the distance between the CdSe quantum dots and the Au electrode, which decreases the electrochemiluminescent intensity in a linear fashion, proportional to the concentration of Pb(II). The linear range of the sensor was 10-10 to 10-8 mol/L (R = 0.9819) with a detection limit of 10-10 mol/L. This sensor detected Pb(II) in real water samples with satisfactory results.

  12. 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/)

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Predicting As, Cd and Pb uptake by rice and vegetables using field data from China

    Institute of Scientific and Technical Information of China (English)

    Hongzhen Zhang; Yongming Luo; Jing Song; Haibo Zhang; Jiaqi Xia; Qiguo Zhao

    2011-01-01

    Plant uptake factor (PUF), single-variable regression of natural log-transformed concentrations in rice grain/vegetables versus natural log-transformed concentrations in soil and multiple-variable regression with soil concentrations and pH, was derived, validated and compared based on the paired crop and soil data collected from studies regarding As, Cd and Pb contaminated croplands in China.Results showed that the median value of PUF did not present deterministic prediction. But after natural logarithm transformation, the PUF followed Gaussian distribution which could be useful in risk assessment. The single-variable regression models were significant for As, Cd and Pb uptake both by rice and vegetables; however, the standard errors of all the regressions were comparatively large.Soil pH as a variable was generally significant but it only contributed positively to model fit for Cd uptake. After model comparison and selection, the upper 95% prediction limits of the multiple regression model for Cd uptake by rice was recommended to calculate screening value of Cd for paddy soil based on the limit for Cd concentration in rice grain.

  14. A Diffusive Gradient-in-Thin-Film Technique for Evaluation of the Bioavailability of Cd in Soil Contaminated with Cd and Pb

    Directory of Open Access Journals (Sweden)

    Peifang Wang

    2016-06-01

    Full Text Available Management of heavy metal contamination requires accurate information about the distribution of bioavailable fractions, and about exchange between the solid and solution phases. In this study, we employed diffusive gradients in thin-films (DGT and traditional chemical extraction methods (soil solution, HOAc, EDTA, CaCl2, and NaOAc to determine the Cd bioavailability in Cd-contaminated soil with the addition of Pb. Two typical terrestrial species (wheat, Bainong AK58; maize, Zhengdan 958 were selected as the accumulation plants. The results showed that the added Pb may enhance the efficiency of Cd phytoextraction which is indicated by the increasing concentration of Cd accumulating in the plant tissues. The DGT-measured Cd concentrations and all the selected traditional extractants measured Cd concentrations all increased with increasing concentration of the addition Pb which were similar to the change trends of the accumulated Cd concentrations in plant tissues. Moreover, the Pearson regression coefficients between the different indicators obtained Cd concentrations and plants uptake Cd concentrations were further indicated significant correlations (p < 0.01. However, the values of Pearson regression coefficients showed the merits of DGT, CaCl2, and Csol over the other three methods. Consequently, the in situ measurement of DGT and the ex situ traditional methods could all reflect the inhibition effects between Cd and Pb. Due to the feature of dynamic measurements of DGT, it could be a robust tool to predict Cd bioavaiability in complex contaminated soil.

  15. A Diffusive Gradient-in-Thin-Film Technique for Evaluation of the Bioavailability of Cd in Soil Contaminated with Cd and Pb.

    Science.gov (United States)

    Wang, Peifang; Wang, Teng; Yao, Yu; Wang, Chao; Liu, Cui; Yuan, Ye

    2016-06-02

    Management of heavy metal contamination requires accurate information about the distribution of bioavailable fractions, and about exchange between the solid and solution phases. In this study, we employed diffusive gradients in thin-films (DGT) and traditional chemical extraction methods (soil solution, HOAc, EDTA, CaCl₂, and NaOAc) to determine the Cd bioavailability in Cd-contaminated soil with the addition of Pb. Two typical terrestrial species (wheat, Bainong AK58; maize, Zhengdan 958) were selected as the accumulation plants. The results showed that the added Pb may enhance the efficiency of Cd phytoextraction which is indicated by the increasing concentration of Cd accumulating in the plant tissues. The DGT-measured Cd concentrations and all the selected traditional extractants measured Cd concentrations all increased with increasing concentration of the addition Pb which were similar to the change trends of the accumulated Cd concentrations in plant tissues. Moreover, the Pearson regression coefficients between the different indicators obtained Cd concentrations and plants uptake Cd concentrations were further indicated significant correlations (p < 0.01). However, the values of Pearson regression coefficients showed the merits of DGT, CaCl₂, and Csol over the other three methods. Consequently, the in situ measurement of DGT and the ex situ traditional methods could all reflect the inhibition effects between Cd and Pb. Due to the feature of dynamic measurements of DGT, it could be a robust tool to predict Cd bioavaiability in complex contaminated soil.

  16. Application of PbWO4 crystal scintillators in experiment to search for double beta decay of 116Cd

    CERN Document Server

    Danevich, F A; Kobychev, V V; Kropivyansky, B N; Nagorny, S S; Nikolaiko, A S; Poda, D V; Tretyak, V I; Yurchenko, S S; Grinyov, B V; Nagornaya, L L; Pirogov, E N; Ryzhikov, V D; Brudanin, V B; Fedorov, M; Korzhik, M; Lobko, A; Miussevitch, O; Solsky, I M

    2004-01-01

    PbWO4 crystal scintillators are discussed as an active shield and light-guides in 116Cd double beta decay experiment with CdWO4 scintillators. Scintillation properties and radioactive contamination of PbWO4 scintillators were investigated. Energy resolution of CdWO4 detector, coupled to PbWO4 crystal as a light-guide, was tested. Efficiency of PbWO4-based active shield to suppress background from the internal contamination of PbWO4 crystals was calculated. Using of lead tungstate crystal scintillators as high efficiency 4-pi active shield could allow to build sensitive double beta experiment with 116CdWO4 crystal scintillators.

  17. First-principles study of roles of Cu and Cl in polycrystalline CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ji-Hui; Park, Ji-Sang; Metzger, Wyatt [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Yin, Wan-Jian [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); College of Physics, Optoelectronics and Energy and Collaborative, Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Wei, Su-Huai, E-mail: suhuaiwei@csrc.ac.cn [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Beijing Computational Science Research Center, Beijing 100094 (China)

    2016-01-28

    Cu and Cl treatments are important processes to achieve high efficiency polycrystalline cadmium telluride (CdTe) solar cells, thus it will be beneficial to understand the roles they play in both bulk CdTe and CdTe grain boundaries (GBs). Using first-principles calculations, we systematically study Cu and Cl-related defects in bulk CdTe. We find that Cl has only a limited effect on improving p-type doping and too much Cl can induce deep traps in bulk CdTe, whereas Cu can enhance p-type doping of bulk CdTe. In the presence of GBs, we find that, in general, Cl and Cu will prefer to stay at GBs, especially for those with Te-Te wrong bonds, in agreement with experimental observations.

  18. Interaction between Cd and Pb in the soil-plant system:a case study of an arid oasis soil-cole system

    Institute of Scientific and Technical Information of China (English)

    ZhuanJun ZHAO; ZhongRen NAN; ZhaoWei WANG; YiMing YANG; Masayuki SHIMIZU

    2014-01-01

    The Hexi Corridor, our study area, is located in Northwest China and is also the most developed area of oasis farming in arid regions of Northwestern China. However, the rapid development of metallurgy and chemical industries in this region poses a great threat to the accumulation of heavy metals in crops. The objectives of this study are (1) to determine the influence of heavy metals on plant growth;(2) to assess the translocation capability of heavy metals in soil-plant system; and (3) to investigate the interaction between heavy metals. Pot experiments were conducted on cole (Brassica campestris L.) grown in the arid oasis soils singly and jointly treated with cad-mium (Cd) and lead (Pb). Nine treatments were applied into the pots. Under the same planting conditions, three scenarios of Cd, Pb and Cd-Pb were designed to compare the interaction between Cd and Pb. The results showed that the response of cole weights to Cd, Pb and Cd-Pb treatments was slight, while Cd and Pb uptakes in cole were more sensitive to the single effects of Cd and Pb concentration in soils from the lower treatment levels. Under the influence of the single Cd, Pb and joint Cd-Pb treatments, Cd concentrations were lower in the cole roots than in the shoots, while for Pb, the results were opposite. Comparison studies revealed that the interaction of Cd and Pb could weaken the cole’s ability to uptake, concentrate and translocate heavy metals in arid oasis soils.

  19. Effect of Cu doping on the properties of ZnTe:Cu thin films and CdS/CdTe/ZnTe solar cells

    Science.gov (United States)

    Tang, J.; Mao, D.; Trefny, J. U.

    1997-02-01

    The effects of Cu doping concentration and post-deposition annealing treatment on the properties of ZnTe thin films were investigated in an effort to decrease the Cu doping concentration and improve the long-term stability of CdS/CdTe/ZnTe solar cells. The structural, compositional, and electrical properties were studied systematically using x-ray diffraction (XRD), electron microprobe, Hall effect and conductivity measurements. XRD measurements indicated that the crystalline phase of as-deposited and low-temperature annealed ZnTe films is dependent on Cu doping concentration. Low-Cu-doped films exhibited zincblende phase, whereas high-Cu-doped films showed wurtzite phase. After annealing at high temperature (⩾350 °C), all films exhibited zincblende structure. Electron probe microanalysis revealed a deficiency of cations in low-Cu-doped films and an excess of cations in high-Cu-doped films. Hall effect measurements revealed a dependence of hole mobility on Cu doping concentration with the highest mobility (20 cm2/Vṡs) obtained at a low Cu concentration. Carrier concentrations higher than mid-1016cm-3 were obtained at a Cu concentration of 2 at. % and relatively low annealing temperatures. Studies of the activation energy of dark conductivity suggested that intrinsic defects (e.g., Zn vacancies) are the dominant acceptors for Cu concentrations lower than 4.5 at. %. Finally, ZnTe films with Cu concentrations as low as 1 at. % were used successfully as a back contact layer in CdTe based solar cells. Fill factors over 0.70 were obtained using ZnTe films of low Cu concentrations.

  20. A Study of Occurrences of Ag in Pb-Zn-Cu Ore Deposits in China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A systematic study of occurrences of silver in 156 Pb-Zn-Cu ore deposits indicates that silver mainly occurs in nonferrous metal ore deposits in forms of association and paragenesis. It occurs mainly as independent minerals in nature and occasionally as ion adsorption, isomorphous or amorphous silver minerals. Nearly 190 silver minerals have been discovered in China. Their shapes, constituents, textures, grain sizes, embedded types, distribution patterns, mineral assemblages and metallogenic series suggest that these characteristics are closely related to geneses of deposits and dependent of ore-forming conditions. Pb, Zn and Cu sulphides are the main carrier minerals of silver. The partition of silver in ore is constrained by the mineralization intensity, grain size and embedded form of silver minerals and mineral assemblages.

  1. Optical properties of 60B2O3–(40–)PbO–MCl2 and 50B2O3–(50–) PbO–MCl2 (M = Pb, Cd) glasses

    Indian Academy of Sciences (India)

    Shajo Sebastian; M Abdul Khadar

    2004-04-01

    Optical absorption and transmittance spectra of 60B2O3–(40–)PbO–MCl2 and 50B2O3–(50–) PbO–MCl2 (M = Pb, Cd) (10 ≤ ≤ 20) glasses of varying composition were recorded in the UV-visible region. Various optical parameters such as optical energy gap (opt), Urbach energy (e), refractive index (0), optical dielectric constant (∝), and ratio of carrier concentration to the effective mass (/*) were determined. The variation of optical energy gap with increase in the concentration of PbCl2 or CdCl2 is discussed.

  2. Varying effect of biochar on Cd, Pb and As mobility in a multi-metal contaminated paddy soil.

    Science.gov (United States)

    Yin, Daixia; Wang, Xin; Chen, Can; Peng, Bo; Tan, Changyin; Li, Hailong

    2016-06-01

    Cd, Pb and As stand as the most prominent contaminants prevailing in Chinese soils. In the present study, biochars derived from water hyacinth (BCW) and rice straw (BCR) were investigated regarding their applicability and durability in soil Cd, Pb, and As immobilization under acid precipitation. Total Cd, Pb, and As in both BCs were below the maximum allowed threshold according to biochar toxicity standard recommended by International Biochar Initiative. To evaluate BCs effect on Cd, Pb, As bioavailability and mobility, CaCl2, KH2PO4 and SPLP extractions were firstly carried out. In neutral extraction with CaCl2 and KH2PO4, significantly reduced Cd/Pb concentrations in CaCl2 extract along with elevated KH2PO4-extractable As were recorded with either BC at 2% or 5%. In SPLP with simulated acid rainwater as extractant, comparable Cd, Pb and As levels were determined in SPLP extract with 2% BCW, while slight to significant increase in SPLP-Cd, Pb or As was recorded with other treatments. Longer-term leaching column test further confirmed the high durability of 2% BCW in Cd immobilization under continuous acid exposure. In parallel, little increase in As concentrations in eluate was determined with 2% BCW compared to no-biochar control, indicating a lowered risk of As mobilization with acid input. However, remarkably higher Pb in leachate from both BCW-only control and 2% BCW-amended soils were noticed at the initial stage of acid leaching, indicating a higher acid-solubility of Pb minerals in BCW (most probably PbO) than in tested soil (PbO2, PbAs2O6). Taken together, BCW exhibited important potential for soil Cd sequestration with little effect on As mobilization under acid precipitation. But it may simultaneously load highly acid-soluble Pb minerals into soils, resulting in elevated Pb mobility upon acid exposure. Therefore, more stringent threshold for Pb content in biochar need to be put forward to secure biochar application in soils subject to anthropogenic

  3. The effect of intermetallic compound morphology on Cu diffusion in Sn-Ag and Sn-Pb solder bump on the Ni/Cu Under-bump metallization

    Science.gov (United States)

    Jang, Guh-Yaw; Duh, Jenq-Gong

    2005-01-01

    The eutectic Sn-Ag solder alloy is one of the candidates for the Pb-free solder, and Sn-Pb solder alloys are still widely used in today’s electronic packages. In this tudy, the interfacial reaction in the eutectic Sn-Ag and Sn-Pb solder joints was investigated with an assembly of a solder/Ni/Cu/Ti/Si3N4/Si multilayer structures. In the Sn-3.5Ag solder joints reflowed at 260°C, only the (Ni1-x,Cux)3Sn4 intermetallic compound (IMC) formed at the solder/Ni interface. For the Sn-37Pb solder reflowed at 225°C for one to ten cycles, only the (Ni1-x,Cux)3Sn4 IMC formed between the solder and the Ni/Cu under-bump metallization (UBM). Nevertheless, the (Cu1-y,Niy)6Sn5 IMC was observed in joints reflowed at 245°C after five cycles and at 265°C after three cycles. With the aid of microstructure evolution, quantitative analysis, and elemental distribution between the solder and Ni/Cu UBM, it was revealed that Cu content in the solder near the solder/IMC interface played an important role in the formation of the (Cu1-y,Niy)6Sn5 IMC. In addition, the diffusion behavior of Cu in eutectic Sn-Ag and Sn-Pb solders with the Ni/Cu UBM were probed and discussed. The atomic flux of Cu diffused through Ni was evaluated by detailed quantitative analysis in an electron probe microanalyzer (EPMA). During reflow, the atomic flux of Cu was on the order of 1016-1017 atoms/cm2sec in both the eutectic Sn-Ag and Sn-Pb systems.

  4. Density Of The Copper-Rich Cu-Pb-Fe Alloys

    Directory of Open Access Journals (Sweden)

    Sak T.

    2015-09-01

    Full Text Available Density of the copper-rich corner of the ternary Cu-Pb-Fe alloys was determined with the dilatometric method. Investigated alloys had constant copper content equal to 0.9, 0.8 and 0.7 mole fraction, and varied iron concentration up to 0.1 mole fraction. A model predicting the density of ternary solution from knowledge of density of pure component and the excess of molar volume for limiting binaries is proposed.

  5. Adsorption of Cu2+ and Pb2+ ion on dolomite powder.

    Science.gov (United States)

    Pehlivan, Erol; Ozkan, Ali Müjdat; Dinç, Salih; Parlayici, Serife

    2009-08-15

    Natural Turkish dolomite was shown to be effective for removing Cu(2+) and Pb(2+) from aqueous solution. Selected information on pH, dose required, initial metal concentration, adsorption capacity of the raw dolomite powder was evaluated for its efficiency in adsorbing metal ions. Dolomite exhibited good Cu(2+) and Pb(2+) removal levels at all initial metal amount tested (0.04-0.32 mmol, 20 mL). It is important to note that the adsorption capacities of the materials in equilibrium vary, depending on the characteristics of the individual adsorbent, the initial concentration of the adsorbate and pH of the solution. One hour was enough for the removal of metal ions from (0.2 mmol in 20 mL) aqueous solution. Effective removal of metal ions was demonstrated at pH values of 5.0. The adsorptive behavior of dolomite was described by fitting data generated from the study of the Langmuir and Freundlich isotherm models. The adsorption capacity of dolomite was found as 8.26 mg for Cu(2+) and 21.74 mg for Pb(2+), respectively, from the calculation of adsorption isotherm equation. More than 85% of studied cations were removed by dolomite from aqueous solution in single step. The mechanism for cations removal by dolomite includes surface complexation and ion exchange.

  6. Comparative analysis on homogeneity of Pb and Cd in epoxy molding compounds

    Institute of Scientific and Technical Information of China (English)

    Kyun-Gmee LEE; Yong-Keun SON; Jin-Sook LEE; Tai-Min NOH; Hee-Soo LEE

    2011-01-01

    Reference materials for quantitative determination of regulated heavy metals, such as Pb and Cd in electronic components,were designed and investigated in terms of stability and homogeneity. Reference materials with two concentration levels of heavy metals were prepared by spiking Pb and Cd compounds to epoxy molding compounds made by mixing silica powders and epoxy resin. The concentration changes of the reference materials during stability test for I a were not observed. In the homogeneity assessment, the as-prepared reference materials were studied by using three different analytical tools, inductively coupled plasma atomic emission spectrometry (ICP-AES). X-ray fluoroescence spectrometry (XRF) and laser ablation ICP mass. The results show different homogeneities by the characteristics of analytical tools and the materials.

  7. DETERMINAÇÃO DE Cd E Pb EM AMOSTRAS DE GOMA XANTANA POR GF AAS

    Directory of Open Access Journals (Sweden)

    Alexander O. de Souza

    2015-02-01

    Full Text Available This paper describes the evaluation of a method for determination of Cd and Pb in xanthan gum samples by Graphite Furnace Atomic Absorption Spectrometry (GF AAS using NH4H2PO4 as the chemical modifier. The sample preparation was performed using a reflux system adapted in the digestion tubes. With this system it was possible to increase the temperature of the digester block above the boiling point of the reaction medium, preventing loss of analyte and excessive evaporation of acids during heating. Samples were digested with HNO3 for 3 h in a digester block at 220 ºC. The limits of detection for Cd and Pb were 2.2 and 33.8 ng g-1, respectively. The RSDs for both analytes were, on average, lower than 5.0% and accuracy was verified by recovery tests, yielding values in the 83-100% range.

  8. The Liquid-Liquid Extraction of Toxic Metals (Cd, Hg and Pb by Calixarenes

    Directory of Open Access Journals (Sweden)

    D. Max Roundhill

    2009-12-01

    Full Text Available Toxic metals (Cd, Hg and Pb are mostly present in the environment due to natural phenomenon and human activities as well. Exposure of these non-essential elements in the environment causes severe effects. They are known to cause problems in humans as well as in aquatic life. In this work, we demonstrate various studies regarding liquid-liquid extraction of selected ions with different functionalized calixarenes. This review article briefly discusses several molecular designs of calixarenes for divalent ion (Cd2+, Hg2+ and Pb2+ recognition; as well as the relationship between structure and selectivity of the macrocycles is elaborated. The article does not, however, attempt to cover all of the different approaches to these toxic metal ions extraction.

  9. Crystal and electronic structure of PbTe/CdTe nanostructures

    Directory of Open Access Journals (Sweden)

    Sankowski Piotr

    2011-01-01

    Full Text Available Abstract In this article, the authors reported a theoretical study of structural and electronic properties of PbTe inclusions in CdTe matrix as well as CdTe nano-clusters in PbTe matrix. The structural properties are studied by ab initio methods. A tight-binding model is constructed to calculate the electron density of states (DOS of the systems. In contrast to the ab initio methods, the latter allows studying nanostructures with diameters comparable to the real ones. The calculations show that both kinds of inclusions lead to changes of the DOS of the carriers near the Fermi level, which may affect optical, electrical and thermoelectric properties of the material. These changes depend on the size, shape, and concentration of inclusions.

  10. Analysis of Cu Diffusion in ZnTe-Based Contacts for Thin-Film CdS/CdTe Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Narayanswamy, C. (Department of Physics & Astronomy, University of Toledo); Gessert, T. A. and Asher, S. E. (National Renewable Energy Laboratory)

    1998-10-27

    Ohmic contacts to thin-film CdS/CdTe photovoltaic devices have been formed using a two-layer contact interface of undoped ZnTe (ZnTe) and Cu-doped ZnTe (ZnTe:Cu), followed by Ni or Ti as an outer metallization. Secondary ion mass spectroscopy (SIMS) is used to study Cu diffusion within this back-contact structure, and also, to monitor Cu diffusion from the contact into the CdTe. When Ni metallization is used, the ZnTe:Cu layer becomes increasingly depleted of Cu, and Ni diffusion into the ZnTe:Cu increases as the contact deposition temperature increases from 100 C to 300 C. Cu depletion is not observed when Ni is replaced with Ti. Diffusion of Cu from the ZnTe:Cu layer into the ZnTe layer also increases with contact deposition temperature, and produces a buildup of Cu at the ZnTe/CdTe interface. High-mass resolution SIMS indicates that, although Cu levels in the CdTe remain low, Cu diffusion from the contact proceeds into the CdTe layer and toward the CdTe/CdS junction region.

  11. The crystal structure of kudriavite, (Cd,Pb)Bi2S4

    DEFF Research Database (Denmark)

    Balic Zunic, Tonci; Makovicky, Emil

    2007-01-01

    The crystal structure of kudriavite, (Cd,Pb)Bi2S4, a new mineral species, was solved from single-crystal X-ray-diffraction data and refi ned to R = 4.9% (4.3% for a model with split mixed-cation sites). Lattice parameters are a 13.095(1), b 4.0032(3), c 14.711(1) Å, 115.59(1)°, V 695.6(1) Å3...

  12. Tolerance and biosorption of copper (Cu) and lead (Pb) by filamentous fungi isolated from a freshwater ecosystem

    Institute of Scientific and Technical Information of China (English)

    Nur Liyana Iskandar; Nur Ain Izzati Mohd Zainudin; Soon Guan Tan

    2011-01-01

    Filamentous fungi are able to accumulate significant amount of metals from their environment.The potential of fungal biomass as agents for biosorption of heavy metals from contaminated sediments is currently receiving attention.In the present study, a total of 41 isolates of filamentous fungi obtained from the sediment of the Langat River, Selangor, Malaysia were screened for their tolerance and uptake capability of copper (Cu) and lead (Pb).The isolates were identified as Aspergillus niger, A.fumigatus, Trichoderma asperellum, Penicillium simplicissimum and P.janthinellum.A.niger and P simplicissimum, were able to survive at 1000 mg/L of Cu(Ⅱ)concentration on Potato Dextrose Agar (PDA) while for Pb, only A.niger survived at 5000 mg/L concentration.The results showed that A.niger, P.simplicissimum and T.asperellum have a better uptake capacity for Pb compared to Cu and the findings indicated promising biosorption of Cu and Pb by these filamentous fungi from aqueous solution.The present study was also determined the maximum removal of Cu(Ⅱ) and Pb(Ⅱ) that was performed by A.niger.The metal removal which occurred at Cu(Ⅱ) 200 mg/L was (20.910 ±0.581) mg/g and at 250 mg/L of Pb(Ⅱ) was (54.046 ± 0.328) mg/g.

  13. Thermophysical Properties of Sn-Ag-Cu Based Pb-Free Solders

    Science.gov (United States)

    Kim, Sok Won; Lee, Jaeran; Jeon, Bo-Min; Jung, Eun; Lee, Sang Hyun; Kang, Kweon Ho; Lim, Kwon Taek

    2009-06-01

    Lead-tin (Pb-Sn) alloys are the dominant solders used for electronic packaging because of their low cost and superior properties required for interconnecting electronic components. However, increasing environmental and health concerns over the toxicity of lead, combined with global legislation to limit the use of Pb in manufactured products, have led to extensive research and development studies of lead-free solders. The Sn-Ag-Cu ternary eutectic alloy is considered to be one of the promising alternatives. Except for thermal properties, much research on several properties of Sn-Ag-Cu alloy has been performed. In this study, five Sn-xAg-0.5Cu alloys with variations of Ag content x of 1.0 mass%, 2.5 mass%, 3.0 mass%, 3.5 mass%, and 4.0 mass% were prepared, and their thermal diffusivity and specific heat were measured from room temperature to 150 °C, and the thermal conductivity was calculated using the measured thermal diffusivity, specific heat, and density values. Also, the linear thermal expansion was measured from room temperature to 170 °C. The results show that Sn-3.5Ag-0.5Cu is the best candidate because it has a maximum thermal conductivity and a low thermal expansion, which are the ideal conditions to be a proper packaging alloy for effective cooling and thermostability.

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

    Science.gov (United States)

    Merizalde, Carlos; Cabrera, José-María; Prado, José-Manuel

    2007-04-01

    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.

  15. Modelling atmospheric bulk deposition of Pb, Zn and Cd near a former Pb-Zn mine in West Greenland using transplanted Flavocetraria nivalis lichens.

    Science.gov (United States)

    Søndergaard, Jens; Bach, Lis; Asmund, Gert

    2013-03-01

    Atmospheric deposition of lead (Pb), zinc (Zn) and cadmium (Cd) was investigated near the former Black Angel Pb-Zn mine in Maarmorilik, West Greenland during 2010-2011. Thalli of the lichen Flavocetraria nivalis were transplanted from an uncontaminated site into sites near the mine and collected the following year. At 20 of the total 21 sites, concentrations of Pb, Zn and Cd were significantly elevated in lichens after 1 year of transplantation compared to initial concentrations. Elevated concentrations were observed within a distance of approx. 20 km from the mining area. Concentrations decreased with increasing distance from the mine and the relation was well described using a power function with a negative exponent (r(2)=0.90; 0.83 and 0.83 for Pb; Zn and Cd). To examine the relation between metal concentrations/uptake in lichen transplants and atmospheric bulk deposition, 10 Bergerhoff dust samplers were placed near lichen transplants and samplers and lichens were collected after a 7-weeks exposure period. A significant linear correlation was observed between metal concentrations in lichen transplants and atmospheric bulk metal deposition (r(2)=0.94; 0.88 and 0.89 for Pb; Zn and Cd). Combining the results and including an area distribution within a defined metal deposition area, the "annual" deposition of Pb, Zn and Cd as dust was estimated during the 2010-2011 snow-free period (∼5 months). The results reveal that 20 years after mine closure, 770 kg Pb, 3700 kg Zn and 24 kg Cd were still being deposited as dust per year (snow-free period only) within a distance of 20 km from the mine.

  16. Adsorption of Pb, Cd to Fe, Mn oxides in natural freshwater surface coatings developed in different seasons

    Institute of Scientific and Technical Information of China (English)

    DONG De-ming; YANG Fan; LI Yu; HUA Xiu-yi; L(U) Xiao-jun; ZHANG Jing-jing

    2005-01-01

    Metal oxides( Fe, Mn oxides) in natural surface coatings(biofilms and associated minerals) are believed to play a significant role in the fate and transport of trace metal in aquatic environments. Seasonal variation of Fe, Mn oxides and organic materials in surface coatings, which were developed periodically on glass slides in Nanhu Lake, Jilin Province, China over the time frame of three seasons,was investigated in order to understand the influence of metal oxides on Pb and Cd adsorption to heterogeneous surface coating materials(biofilm). Pb and Cd adsorption was measured under controlled laboratory conditions(mineral salts solution with defined speciation, ionic strength 0.05 mol/L, 25℃ and pH 6.0). The classical Langmuir adsorption isotherm was applied to estimate equilibrium coefficients of Pb and Cd adsorption to the surface coatings. In general, components in the surface coatings varied greatly with seasons altering and obtained higher concentrations in summer while the content of iron oxides always exceeded that of manganese oxides. Correlation analyses between the maximum adsorption of Pb and Cd and components in the surface coatings developed periodically indicated that Pb phase association with Mn oxides and Cd phase association with Fe oxides as well as Mn oxides were statistically significant. Effect of Mn oxides on Cd adsorption was confirmed in view of its higher content in the surface coatings. The importance of ferromanganese oxides for Pb and Cd adsorption to the natural surface coatings developed in different seasons was evidenced.

  17. Processing Bi-Pb-Sr-Ca-Cu-O superconductors from amorphous state

    Science.gov (United States)

    Chiang, C. K.; Freiman, S. W.; Wong-Ng, W.; Hwang, N. M.; Shapiro, A. J.; Hill, M. D.; Cook, L. P.; Shull, R. D.; Swartzendruber, L. J.; Bennett, L. H.

    1990-01-01

    Researchers produced superconducting ceramics of the Bi-Pb-Sr-Ca-Cu-O system started from a glass. To form the glass, the mixed oxide powder was melted at 1200 C in air. The liquid was quenched rapidly by pouring it onto an aluminum plate and rapidly pressing with another plate. The quenched compound was in the form of black amorphous solid, whose x-ray powder pattern has no crystalline peaks. After heat treatment at high temperatures, the glass crystallized into a superconductor. The crystalline phases in the superconductor identified using x-ray diffraction patterns. These phases were that associated with the superconducting phases of T(sub c) = 80 K (Bi2Ca1Sr2Cu2Ox) and of T(sub c) = 110 K (Bi2Ca2Sr2Cu3Ox). The dc resistivity and the ac susceptibility of these superconductors were studied.

  18. Competitive adsorption of Pb and Cd on bacteria-montmorillonite composite.

    Science.gov (United States)

    Du, Huihui; Chen, Wenli; Cai, Peng; Rong, Xingmin; Feng, Xionghan; Huang, Qiaoyun

    2016-11-01

    The characteristics and mechanisms of competitive adsorption of trace metals on bacteria-associated clay mineral composites have never been studied, despite their being among the most common organic-mineral complexes in geological systems. Herein, competitive adsorption of Pb and Cd on Pseudomonas putida-montmorillonite composite was investigated through adsorption-desorption experiment, isothermal titration calorimetry (ITC), and synchrotron micro X-ray fluorescence (μ-XRF). From the experiment, stronger competition was observed on clay mineral than on bacteria-clay composite because more non-specific sites accounted for heavy metal adsorption on clay mineral surface at the studied pH 5. Both competing heavy metals tended to react with bacterial fractions in the composite, which was verified by the higher correlation of Cd (and Pb) with Zn (R(2) = 0.41) elemental distribution than with Si (R(2) = 0.10). ITC results showed that competitive adsorption exhibited a lower entropy change (ΔS) at the metal-sorbent interfaces compared with single-metal adsorption, revealing that Cd and Pb are bound to the same types of adsorption sites on the sorbent. The competitive effect on bacteria-clay composite was found to be helpful for a better understanding on the fixation, remobilization and subsequent migration of heavy metals in multi-metal contaminated environments.

  19. Cystine-modified biomass for Cd(II) and Pb(II) biosorption

    Energy Technology Data Exchange (ETDEWEB)

    Yu Junxia [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Tong Mi [Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, College of Chemistry and Materials Science, South-Central University for Nationalities, Wuhan 430074 (China); Sun Xiaomei [Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, College of Chemistry and Materials Science, South-Central University for Nationalities, Wuhan 430074 (China); Li Buhai [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China) and Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, College of Chemistry and Materials Science, South-Central University for Nationalities, Wuhan 430074 (China)]. E-mail: libuhai@163.com

    2007-05-08

    The surface of dried biomass of baker's yeast was modified by crosslinking cystine with glutaraldehyde. X-ray photoelectron spectroscopy and microscope were used to characterize the modified biomass. The adsorption capacity of the modified biomass for Cd{sup 2+} and Pb{sup 2+} showed an increase compared with the pristine biomass due to the presence of cystine on the biomass surface. Experimental data showed that the adsorption of the two metal ions increased with time until equilibrium was achieved. The adsorption capacities for Cd{sup 2+} and Pb{sup 2+} were 11.63 and 45.87 mg g{sup -1}, respectively, which were determined from the Langmuir isotherm. The loaded biosorbent was regenerated using HCl solution and could be used repeatedly at six times with little loss of uptake capacity. FTIR spectroscopy revealed that carboxyl, amide, and hydroxyl groups on the biomass surface were involved in the adsorption of Cd{sup 2+} and Pb{sup 2+}.

  20. Microscopic Study of the Isoscalar Giant Monopole Resonance in Cd, Sn and Pb Isotopes

    CERN Document Server

    Cao, Li-Gang; Colo, G

    2012-01-01

    The isoscalar giant monopole resonance (ISGMR) in Cd, Sn and Pb isotopes has been studied within the self-consistent Skyrme Hartree-Fock+BCS and quasi-particle random phase approximation (QRPA). Three Skyrme parameter sets are used in the calculations, i.e., SLy5, SkM* and SkP, since they are characterized by different values of the compression modulus in symmetric nuclear matter, namely K=230, 217, and 202 MeV, respectively. We also investigate the effect of different types of pairing forces on the ISGMR in Cd, Sn and Pb isotopes. The calculated peak energies and the strength distributions of ISGMR are compared with available experimental data. We find that SkP fails completely to describe the ISGMR strength distribution for all isotopes due to its low value of the nuclear matter incompressibility, namely K=202 MeV. On the other hand, the SLy5 parameter set, supplemented by an appropriate pairing interaction, gives a reasonable description of the ISGMR in Cd and Pb isotopes. A better description of ISGMR in ...

  1. Percentage of toxic trace elements; Pb, Cr and Cd in certain plastic toys, Isfahan City

    Directory of Open Access Journals (Sweden)

    F Kavehzadeh

    2006-04-01

    Full Text Available Introduction: Recent investigations have detected the presence of significant levels of heavy metals (chromium, lead and cadmium in toys and other PVC products manufactured for children. In some countries, addition of compounds containing toxic metals to toys are limited or prohibited. Methods: To evaluate the safety of some of the plastic toys in the city of Isfahan with respect to toxic trace metals, pb, cr and cd, 75 samples of three types of toys were collected from the toy shop’s and were digested with acid with the two methods ISIRI and ASTM. The heavy metals were determined using atomic absorption spectrophotometer. Variance analysis and T-test were used for data analysis. Results: The result of the study showed that the products tested contained lead, chromium and cadmium and the highest and lowest concentration were related to Pb and Cd, respectively. The statistical analysis of the samples showed that there are no significant differences between ASTM and ISIRI digestion methods. The study revealed that none of the heavy metals in the toy samples exceeded the recommended standard levels. Highest average concentration of Pb and Cd were related to toys with green color and the highest Cr concentration was related to yellow toys in this study. Conclusion: Extensive studies are required to evaluate the quality of the toys being used by children and the toxic trace elements should be eliminated from the plastic materials used for making toys.

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

    Science.gov (United States)

    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.

  3. Metal pollution (Cd, Pb, Zn, and As) in agricultural soils and soybean, Glycine max, in southern China.

    Science.gov (United States)

    Zhao, Yunyun; Fang, Xiaolong; Mu, Yinghui; Cheng, Yanbo; Ma, Qibin; Nian, Hai; Yang, Cunyi

    2014-04-01

    Crops produced on metal-polluted agricultural soils may lead to chronic toxicity to humans via the food chain. To assess metal pollution in agricultural soils and soybean in southern China, 30 soybean grain samples and 17 soybean-field soil samples were collected from 17 sites in southern China, and metal concentrations of samples were analyzed by graphite furnace atomic absorption spectrophotometer. The integrated pollution index was used to evaluate if the samples were contaminated by Cd, Pb, Zn and As. Results showed that Cd concentration of 12 samples, Pb concentration of 2 samples, Zn concentration of 2 samples, and As concentrations of 2 samples were above the maximum permissible levels in soils. The integrated pollution index indicated that 11 of 17 soil samples were polluted by metals. Metal concentrations in soybean grain samples ranged from 0.11 to 0.91 mg kg(-1) for Cd; 0.34 to 2.83 mg kg(-1) for Pb; 42 to 88 mg kg(-1) for Zn; and 0.26 to 5.07 mg kg(-1) for As, which means all 30 soybean grain samples were polluted by Pb, Pb/Cd, Cd/Pb/As or Pb/As. Taken together, our study provides evidence that metal pollution is an important concern in agricultural soils and soybeans in southern China.

  4. Constitutive Behavior of Mixed Sn-Pb/Sn-3.0Ag-0.5Cu Solder Alloys

    Science.gov (United States)

    Tucker, J. P.; Chan, D. K.; Subbarayan, G.; Handwerker, C. A.

    2012-03-01

    During the transition from Pb-containing solders to Pb-free solders, joints composed of a mixture of Sn-Pb and Sn-Ag-Cu often result from either mixed assemblies or rework. Comprehensive characterization of the mechanical behavior of these mixed solder alloys resulting in a deformationally complete constitutive description is necessary to predict failure of mixed alloy solder joints. Three alloys with 1 wt.%, 5 wt.%, and 20 wt.% Pb were selected so as to represent reasonable ranges of Pb contamination expected from different 63Sn-37Pb components mixed with Sn-3.0Ag-0.5Cu. Creep and displacement-controlled tests were performed on specially designed assemblies at temperatures of 25°C, 75°C, and 125°C using a double lap shear test setup that ensures a nearly homogeneous state of plastic strain at the joint interface. The observed changes in creep and tensile behavior with Pb additions were related to phase equilibria and microstructure differences observed through differential scanning calorimetric and scanning electron microscopic cross-sectional analysis. As Pb content increased, the steady-state creep strain rates increased, and primary creep decreased. Even 1 wt.% Pb addition was sufficient to induce substantially large creep strains relative to the Sn-3.0Ag-0.5Cu alloy. We describe rate-dependent constitutive models for Pb-contaminated Sn-Ag-Cu solder alloys, ranging from the traditional time-hardening creep model to the viscoplastic Anand model. We illustrate the utility of these constitutive models by examining the inelastic response of a chip-scale package (CSP) under thermomechanical loading through finite-element analysis. The models predict that, as Pb content increases, total inelastic dissipation decreases.

  5. Distribution of Cu and Pb in particle size fractions of urban soils from different city zones of Nanjing, China

    Institute of Scientific and Technical Information of China (English)

    WANG Huan-hua; LI Lian-qing; WU Xin-min; PAN Gen-xing

    2006-01-01

    Soil samples from 4 defined city zones of Nanjing were randomly collected at 0-5 cm and 5-20 cm intervals and size fractions of soil particles were separated from undisturbed bulk soils by low energy dispersion procedure. The total contents of Cu and Pb in the different particle size fractions of the urban soils were analyzed by HNO3-HF-HC1O4 digestion and flame atomic absorption spectrophotometer determination. The total content of Cu and Pb in soil particle size fractions varied with their size and with city zones as well. Both the content and variation with the size fractions of Pb was bigger than of Cu supporting our previous finding that there was Pb pollution to different degrees in the urban soils although the two elements were generally enriched in clay-sized fraction.Contaminated Pb tended to be preferentially enriched in the size fraction of 2000-250 μm and clay-sized fraction. While the size fractions of the soils from newly developed and preserved area contained smaller amount of Cu and Pb, the partitioning of them in coarse and fine particle size fractions were insignificant compared to that from inner residence and commercial area. The very high Pb level over 150 mg/kg of the fine particle fractions from the soils of the inner city could be a cause of high blood Pb level reported of children from the city as acute exposure to Pb of fine particles of the urban soil might occur by soil ingestion and inhalation by young children. Thus, much attention should be paid to the partitioning of toxic metals in fine soil particles of the urban soils and countermeasures against high health risk of Pb exposure by soil ingestion and dust inhalation should be practiced against the health problem of blood Pb for young children from the cities.

  6. Excellent magnetocaloric properties in RE2Cu2Cd (RE = Dy and Tm) compounds and its composite materials

    Science.gov (United States)

    Zhang, Yikun; Yang, Yang; Xu, Xiao; Geng, Shuhua; Hou, Long; Li, Xi; Ren, Zhongming; Wilde, Gerhard

    2016-09-01

    The magnetic properties and magnetocaloric effect (MCE) of ternary intermetallic RE2Cu2Cd (RE = Dy and Tm) compounds and its composite materials have been investigated in detail. Both compounds undergo a paramagnetic to ferromagnetic transition at its own Curie temperatures of TC ~ 48.5 and 15 K for Dy2Cu2Cd and Tm2Cu2Cd, respectively, giving rise to the large reversible MCE. An additionally magnetic transition can be observed around 16 K for Dy2Cu2Cd compound. The maximum values of magnetic entropy change (-ΔSMmax) are estimated to be 17.0 and 20.8 J/kg K for Dy2Cu2Cd and Tm2Cu2Cd, for a magnetic field change of 0-70 kOe, respectively. A table-like MCE in a wide temperature range of 10-70 K and enhanced refrigerant capacity (RC) are achieved in the Dy2Cu2Cd - Tm2Cu2Cd composite materials. For a magnetic field change of 0-50 kOe, the maximum improvements of RC reach 32% and 153%, in comparison with that of individual compound Dy2Cu2Cd and Tm2Cu2Cd. The excellent MCE properties suggest the RE2Cu2Cd (RE = Dy and Tm) and its composite materials could be expected to have effective applications for low temperature magnetic refrigeration.

  7. Comparison of the Molecular Interaction Volume Model with the Wagner Formulae in the Zn-Pb-In and Zn-Sn-Cd-Pb Dilute Solutions

    Institute of Scientific and Technical Information of China (English)

    Dongping TAO; Zhuo CHEN; Dunfang LI; Yifeng GAO; Qianghua SHEN

    2004-01-01

    The coordination numbers in the molecular interaction volume model (MIVM) can be calculated from the common physical quantities of pure liquid metals. A notable feature of the model lie in its capability to predict the thermodynamic properties of solutes in the Zn-Pb-ln and Zn-Sn-Cd-Pb dilute solutions using only the binary infinite dilute activity coefficients, and the predicted values are in good agreement with the experimental data of the dilute solutions.

  8. Adsorption of Pb(II) and Cd(II) from aqueous solutions using titanate nanotubes prepared via hydrothermal method.

    Science.gov (United States)

    Xiong, Lin; Chen, Cheng; Chen, Qing; Ni, Jinren

    2011-05-30

    Titanate nanotubes (TNs) with specific surface areas of 272.31 m(2)g(-1) and pore volumes of 1.264 cm(3)g(-1) were synthesized by alkaline hydrothermal method. The TNs were investigated as adsorbents for the removal of Pb(II) and Cd(II) from aqueous solutions. The FT-IR analysis indicated that Pb(II) and Cd(II) adsorption were mainly ascribed to the hydroxyl groups in the TNs. Batch experiments were conducted by varying contact time, pH and adsorbent dosage. It was shown that the initial uptake of each metal ion was very fast in the first 5 min, and adsorption equilibrium was reached after 180 min. The adsorption of Pb(II) and Cd(II) were found to be maximum at pH in the range of 5.0-6.0. The adsorption kinetics of both metal ions followed the pseudo-second-order model. Equilibrium data were best fitted with the Langmuir isotherm model, and the maximum adsorption capacities of Pb(II) and Cd(II) were determined to be 520.83 and 238.61 mg g(-1), respectively. Moreover, more than 80% of Pb(II) and 85% of Cd(II) adsorbed onto TNs can be desorbed with 0.1M HCl after 3h. Thus, TNs were considered to be effective and promising materials for the removal of both Pb(II) and Cd(II) from wastewater.

  9. Comparison of Pb, Cd Adsorption to Surface Coatings Developed in Natural Waters with that in Plant Effluents

    Institute of Scientific and Technical Information of China (English)

    DONG De-ming; LI Yu; HUA Xiu-yi; ZHANG Jing-jing

    2003-01-01

    The comparative studies of Pb and Cd adsorption to the surface coatings(Fe, Mn, Al oxides, organic materials, and associated minerals), which were developed on glass slides in five natural and two technical waters(plant effluents), were carried out under controlled laboratory conditions(mineral salts solution with defined speciation, ionic strength 0.05 mol/L, 25 ℃ and pH 6.0). The classical Langmuir adsorption isotherm was applied to estimating the equilibrium coefficients of Pb and Cd adsorption to the surface coatings. The results show that the maximum adsorption of Pb and Cd to the surface coatings mentioned above varied widely. There was a systemic increase in the maximum adsorption of Pb and Cd to the surface coatings with increasing the contents of Mn and Fe oxides in the surface coatings in significant correlation, respectively, not only highlighting the relative importance of the metal oxide fraction for Pb and Cd adsorption to the surface coatings developed in natural and technical water samples, but also implying the same adsorption mechanisms of Pb and Cd to the surface coatings developed both in natural and technical water samples.

  10. Potential capacity of Beauveria bassiana and Metarhizium anisopliae in the biosorption of Cd2+ and Pb2+.

    Science.gov (United States)

    Hussein, Khalid A; Hassan, Sedky H A; Joo, Jin Ho

    2011-01-01

    In this study Beauveria bassiana and Metarhizium anisopliae were used as inexpensive and efficient biosorbents for Pb(II) and Cd(II) from aqueous metal solutions. The effects of various physicochemical factors on Pb(II) and Cd(II) biosorption by B. bassiana and M. anisopliae were studied. The optimum pH for Cd(II) and Pb(II) biosorption by two fungal species was achieved at pH 6.0 for Pb(II) and 5.0 Cd(II) at a constant time of 30 min. The nature of fungal biomass and metal ion interactions was evaluated by Fourier transform infrared. The maximum adsorption capacities (q(max)) calculated from Langmuir isotherms for Pb(II), and Cd(II) uptake by B. bassiana were 83.33±0.85, and 46.27±0.12 mg/g, respectively. However, the q(max) obtained for Pb(II) uptake by M. anisopliae was 66.66±0.28 mg/g, and 44.22±0.13 mg/g for Cd(II). B. bassiana showed higher adsorption capacity compared to M. anisopliae. The data obtained imply the potential role of B. bassiana and M. anisopliae for heavy metal removal from aqueous solutions.

  11. Physical, Optical and Electron paramagnetic resonance studies of PbBr2-PbO-B2O3 glasses containing Cu2+ ions

    Science.gov (United States)

    Sekhar, K. Chandra; Hameed, Abdul; Chary, M. Narasimha; Shareefuddin, Md

    2016-09-01

    The glasses with the composition PbBr2-PbO-B2O3 glasses containing Cu2+ ions were prepared by melt quenching technique. X-ray diffractograms revealed the amorphous nature of the glasses. Density and molar volume were determined. Density is found to decrease while the molar volume increases with increase of PbBr2 content. The optical absorption spectra exhibited a broad band corresponding to the d- d transition of Cu2+ ion. From optical absorption spectra Eopt and Urbach energies were determined. Electron Paramagnetic Resonance (EPR) studies were carried out by introducing Cu2+ as the spin probe. Glasses containing transition metal(TM) ions such as Cu2+ give the information about the structure and the site symmetry around the TM ions. EPR spectra of all the glass samples were recorded at X-band frequencies. From the EPR spectra spin-Hamiltonian parameters were evaluated. It was observed that g∥ >g±>ge (2.0023) and A∥>A±. From this values it is concluded that the ground state of Cu2+ is dx2-y2 (2B1g) and the site symmetry around Cu2+ ion is tetragonally distorted octahedral. From the EPR and Optical data bonding coefficients were evaluated. The in plane o-bonding(α2) is moderately ionic while out of plane 7t-bonding(β2) and in plane 7t-bonding(β1 2) are ionic nature

  12. Preparation, Processing and Tunneling in YBa2Cu3O7-δ-Pb Native-Barrier Structures

    Science.gov (United States)

    Frangi, Francesca; Dwir, Benjamin; James, Jonathan H.; Gauzzi, Andrea; Pavuna, Davor

    1993-06-01

    We have developed a procedure for the preparation of small (40× 40 μm2) window-type YBa2Cu3O7-δ-Pb junctions with YSZ insulator and native tunnel barrier. We present the patterning technique of the two electrodes based on photolithography and wet etching. The nature of the barrier is found to be semiconducting. The tunneling measurements show gap-like feature of YBa2Cu3O7-δ at 8.5 meV and some additional features related to Pb and YBa2Cu3O7-δ phonon spectra.

  13. Tunneling characteristics of YBa 2Cu 3O 7-δ-Pb window-type Josephson junctions

    Science.gov (United States)

    Frangi, F.; Dwir, B.; Pavuna, D.

    1992-02-01

    We present the results of tunneling measurements done on window-type, native-barrier YBa 2Cu 3O 7-δ-Pb junctions. We show features in the I-V curves which are related to the gap of YBa 2Cu 3O 7-δ, as well as to the Pb and YBa 2Cu 3O 7-δ phonon spectra. The nature of barrier in these structures is found to be semi-conducting. We can also see the asymmetry in the tunneling curves.

  14. Responses of different Chinese flowering cabbage (brassica parachinensis l.) cultivars to cadmium and lead exposure: screening for Cd + Pb pollution-safe cultivars

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Qiu; Yang, Zhongyi; Xin, Junliang; Yuan, Jiangang; Wang, Jianbing; Xin, Guorong [State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou (China); Wang, Yutao [Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, School of Life Sciences, South China Normal University, Guangzhou, Guangdong (China)

    2011-11-15

    To reduce the potential risks of cadmium (Cd) and lead (Pb) entering the human food chain in vegetables, two pot experiments (Exp. 1 and Exp. 2) were carried out to screen for Cd and Pb pollution-safe cultivars (PSCs) of Chinese flowering cabbage (Brassica parachinensis L.). The three Cd treatments in Exp. 1 (0.114, 0.667, and 1.127 mg kg{sup -1}) showed that Chinese flowering cabbage could easily take up Cd from polluted soils, and there were wide variations in Cd accumulation among different cultivars. The Cd accumulation trait at cultivar level was rather stable under different soil Cd treatments. In Exp. 2, seven cultivars that had been shown in Exp. 1 to be typical high or low accumulators of Cd were selected and six Cd + Pb joint exposure treatments were applied to them. The results showed that there were similar trends of accumulation between Cd and Pb for the tested cultivars, but Pb accumulation by the species was much poorer than that of Cd. It was worth noting that an increase in soil Pb levels significantly (p < 0.01) depressed shoot Cd accumulation. Six cultivars were selected as Cd + Pb PSCs. This study showed that it is feasible to apply a PSC strategy in Chinese flowering cabbage cultivation, to cope with the Cd and Pb contamination commonly found in agricultural soils. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Toxicity of Cu and Cd in Soils and Detoxication by Additives

    Institute of Scientific and Technical Information of China (English)

    GUZONG-LIAN; WULIU-SONG; 等

    1991-01-01

    Results from laboratory experiments indicated that the concentrations and toxicities of both water-soluble and 0.1 M HCl-extractable Cu and Cd from soils were in the order of red soil> yellow brown earth> black earth.The toxicity of soil varied with the concentrations of metals.The form,concentration and toxicity of Cu and Cd in soils were determined by cation exchange capacity,content of organic matter and composition of clay minerals in the soil.Addition of CaCO3 could significantly decrease the concentration and toxicity of water-soluble and 0.1 M HCl-extractable Cu or Cd from the red soil,and could notably transform the Cu and Cd from the water-soluble or exchangeable form into the organic,free oxides-occluded or sulfic form.

  16. Colorimetric detection of Cu2+ and Pb2+ ions using calix[4]arene functionalized gold nanoparticles

    Indian Academy of Sciences (India)

    Ravi Gunupuru; Debdeep Maity; Gopala R Bhadu; Ashish Chakraborty; Divesh N Srivastava; Parimal Paul

    2014-05-01

    Calixarene functionalized gold nanoparticles (CFAuNPs) have been prepared and characterized by spectroscopic and microscopic (TEM) techniques. To use this material as potential colorimetric sensor, the binding property of this new material has been investigated with a large number of metal ions. It exhibited sharp colour change from dark brown to green and blue, detectable by naked-eye, in the presence of Cu2+ and Pb2+ ions, respectively. It has also triggered substantial change in surface plasmon resonance (SPR) band of the functionalized gold nanoparticles, which in case of Pb(II) is due to the inter particle plasmon coupling arising from the metal-induced aggregation of the nanoparticles and for Cu(II), it is because of the formation of AuCu alloy due to anti-galvanic exchange. The size and aggregation of the nanoparticles are confirmed from HRTEM images, elemental analysis and the line profiling for both the metal ions have been done by STEM-EDX analysis.

  17. Au/Cu2Te/CdTe/CdS/TCO/Glass Solar Cells with CdIn2O4 Obtained by Sol-Gel as TCO

    OpenAIRE

    J. Márquez Marín; G. Torres Delgado; M. A. Aguilar Frutis; R. Castanedo Pérez; Zelaya Ángel, O.

    2014-01-01

    An Au/Cu2Te/CdTe/CdS/TCO/glass heterostructure based superstrate solar cells with 2.5 mm2 of area, where the CdTe layer was prepared by means of closed spaced sublimation (CSS) and the CdS by chemical bath, reached an efficiency η value of 12.1%. As transparent conductive oxide (TCO), a thin film of cadmium-indium oxide (CdIn2O4:CIO), obtained by sol-gel technique, was used. A systematic optimization of the thermal activation of the CdTe/CdS/CIO central part of the device with a CdCl2 vapor a...

  18. Band offsets at the CdS/CuInSe[sub 2] heterojunction

    Energy Technology Data Exchange (ETDEWEB)

    Wei, S.; Zunger, A. (National Renewable Energy Laboratory, Golden, Colorado 80401 (United States))

    1993-11-01

    The traditional explanation for the successful electron-hole separation in CdS/CuInSe[sub 2] solar cells rests on the assumption of a type-II band lineup: The conduction-band minimum is assumed to be on the CdS window while the valence-band maximum is assumed to be localized on the CuInSe[sub 2] absorber. This picture of negative conduction-band offset [Delta][ital E][sub [ital c

  19. Degradation mechanisms studies in CdS/CdTe solar cells with ZnTe:Cu/Au back contact

    Science.gov (United States)

    Morgan, D.; Tang, J.; Kaydanov, V.; Ohno, T. R.; Trefny, J. U.

    1999-03-01

    CdS/CdTe/ZnTe:Cu/Au solar cells were fabricated and tested under stressed conditions including enhanced temperature, forward and reverse bias, open circuit, dark and light. Discussion of results was focused mostly on the development of the back contact Schottky diode (increase in series resistance). Changes in the cell parameters were detected based on the analysis of the dynamic resistance of a cell (dV/dJ) at forward biases. A possible role of electromigration of the Cu dopant was discussed.

  20. Degradation mechanisms studies in CdS/CdTe solar cells with ZnTe:Cu/Au back contact

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, D.; Tang, J.; Kaydanov, V.; Ohno, T.R.; Trefny, J.U. [Department of Physics, Colorado School of Mines, Golden, Colorado 80401 (United States)

    1999-03-01

    CdS/CdTe/ZnTe:Cu/Au solar cells were fabricated and tested under stressed conditions including enhanced temperature, forward and reverse bias, open circuit, dark and light. Discussion of results was focused mostly on the development of the back contact Schottky diode (increase in series resistance). Changes in the cell parameters were detected based on the analysis of the dynamic resistance of a cell (dV/dJ) at forward biases. A possible role of electromigration of the Cu dopant was discussed. {copyright} {ital 1999 American Institute of Physics.}

  1. Electrochemical processing of high- Bi(Pb)–Sr–Ca–CuO thin films

    Indian Academy of Sciences (India)

    N V Desai; L A Ekal; D D Shivagan; S H Pawar

    2000-02-01

    Superconducting thin films of Bi(Pb)–Sr–Ca–CuO system were prepared by depositing the film onto silver substrate by d.c. electrodeposition technique with dimethyl sulphoxide bath in order to examine the effect of Pb addition to the BSCCO system. The films were deposited at the potential of – 0.8 V vs saturated calomel electrode (SCE) onto the silver substrate. The different preparative parameters such as deposition potential, deposition time were studied and optimized. These films were then oxidized electrochemically at room temperature in an alkaline (1 N KOH) solution, and also at 600°C temperature in an oxygen atmosphere. The films showed the superconducting behaviour, with values ranging between 85 K and 96 K, respectively.

  2. Effects of heat treatment on diffusion of Cu atoms into CdTe single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Soo, Y. L. [Department of Physics, State University of New York at Buffalo, Amherst, New York 14260 (United States); Huang, S. [Department of Physics, State University of New York at Buffalo, Amherst, New York 14260 (United States); Kim, S. [Department of Physics, State University of New York at Buffalo, Amherst, New York 14260 (United States); Kioseoglou, G. [Department of Physics, State University of New York at Buffalo, Amherst, New York 14260 (United States); Kao, Y. H. [Department of Physics, State University of New York at Buffalo, Amherst, New York 14260 (United States); Compaan, A. D. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Grecu, D. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Albin, D. [National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401 (United States)

    2000-06-19

    Angular dependence of x-ray fluorescence and x-ray absorption fine structure techniques have been used to study the diffusion of Cu atoms into the photovoltaic material CdTe. Depth profile, effective valency, and local structure of Cu atoms in a Cu-doped single crystal of CdTe were investigated before and after a second heat treatment. Enhanced Cu diffusion into the CdTe single crystal was observed as a result of heating at a moderate temperature around 200 degree sign C, resulting in a redistribution of the Cu impurities through a broader depth profile. Some of the Cu atoms are believed either to form small complexes with Te or occupy interstitial sites in the host but accompanied by a large local lattice distortion while others substitute for Cd on the cation sites. The results thus demonstrate that these nondestructive x-ray characterization methods are useful for probing microstructural changes in CdTe photovoltaic materials/devices in which some Cu-containing compounds are used as back contacts. (c) 2000 American Institute of Physics.

  3. 氨基硫脲改性山竹壳对Cd2+、Pb2+的吸附%Adsorption of Cd2+ and Pb2+ on Mangosteen Shell Modified by Thiosemicarbazide

    Institute of Scientific and Technical Information of China (English)

    黄晓东; 刘明华; 林春香

    2012-01-01

    New modified mangosteen (MS) adsorbent was prepared by using thiosemicarbazide and the adsorption behavior of Cd2+ and Pb2+ on mangosteen shell was studied. Results showed tha| pH 6.0 and shaking time 120 min were the optimal conditions for adsorption of Cd2+ and Pb2+. The adsorption capacity of adsorbent could be greatly improved after modified, with the maximum adsorption capacity of Cd2+ and Pb2+ up to 39.37 and 57.14 mg/g respectively. The adsorption process followed a pseudo-second order equation and the equilibrium isotherm was best described by the Langmuir model rather than the Freundlich model.%采用氨基硫脲改性山竹壳,制备新型的改性山竹壳吸附剂,研究其对Cd2+、Pb2+的吸附性能.结果表明,吸附Cd2+、Pb2+的适宜条件为:pH 6.0,吸附时间120 min.改性后山竹吸附剂对Cd2+、Pb2+的吸附容量能有了很大程度的提高,Cd2+、Pb2+最大吸附量分别达到3937、57.14mg/g.吸附过程可以很好地用准二级动力学方程描述,吸附等温线用Langmuir方程的拟合效果优于Freundlich方程.

  4. PENINGKATAN KUALITAS FILM TIPIS CdTe SEBAGAI ABSORBER SEL SURYA DENGAN MENGGUNAKAN DOPING TEMBAGA (Cu

    Directory of Open Access Journals (Sweden)

    P. Marwoto

    2012-12-01

    Full Text Available Film tipis CdTe dengan doping tembaga (Cu berkonsenterasi 2% telah berhasil ditumbuhkan di atas substrat Indium Tin Oxide (ITO dengan metode dc magnetron sputtering. Penelitian ini dilakukan untuk mengetahui pengaruh doping Cu(2% terhadap struktur morfologi, struktur kristal, fotoluminisensi dan resistivitas listrik film CdTe. Citra morfologi Scanning Electron Microscopy (SEM dan hasil analisis struktur dengan X-Ray Diffraction (XRD menunjukkan bahwa film CdTe:Cu(2% mempunyai citra permukaan dan struktur kristal yang lebih sempurna dibandingkan film CdTe tanpa doping. Hasil analisis spektrometer fotoluminisensi menunjukkan bahwa film CdTe dan CdTe(2% mempunyai puncak fotoluminisensi pada tiga panjang gelombang yang identik yaitu 685 nm (1,81 eV, 725 nm (1,71 eV dan 740 nm (1,67 eV. Film CdTe dengan doping Cu(2% memiliki intensitas puncak fotoluminisensi yang lebih tajam pada pita energi 1,81 eV dibandingkan dengan film CdTe tanpa doping. Pengukuran arus dan tegangan (I-V menunjukkan bahwa pemberian doping Cu(2% dapat menurunkan resistivitas film dari 8,40x109 Ωcm menjadi 6,92x105 Ωcm. Sebagai absorber sel surya, kualitas film tipis CdTe telah berhasil ditingkatkan dengan pemberian doping Cu(2%.CdTe:Cu(2% thin film has been successfully grown on Indium Tin Oxide (ITO substrates by using dc magnetron sputtering. This study was carried out in order to investigate the effect of Cu(2% doping on the morphologycal structure, crystal structure, photoluminesence, and resistivity of CdTe thin film. Scanning Electron Microscopy (SEM  images and X-Ray Diffraction (XRD results showed that CdTe:Cu(2% thin film has morphologycal and crystal structures more perfect than undoped CdTe film. Photoluminesence spectroscopy results showed that CdTe and CdTe:Cu(2% thin films have luminesence peak at three identical wevelength regions i.e. 685 nm (1.81 eV, 725 nm (1.71 eV and 740 nm (1.67 eV however CdTe:Cu(2% film shows sharper photoluminescence peak at band

  5. Distributions and pollution assessment of heavy metals Pb, Cd and Cr in the water system of Kendari Bay, Indonesia

    Science.gov (United States)

    Armid, A.; Shinjo, R.; Ruslan, R.; Fahmiati

    2017-02-01

    The concentrations of heavy metals Pb, Cd and Cr in the coastal waters of Kendari Bay were analyzed to assess their pollution status. Water samples from 32 sampling points were analyzed for dissolved heavy metals concentrations by using inductively coupled plasma mass spectrometry (ICP-MS). The RSD(%) of each metal was accounted to analyze the diversity of the heavy metals among 32 sampling points. The results demonstrate that the dissolved heavy metal Pb had the highest concentrations (0.009 to 0.549 μg/L, average = 0.210 μg/L) followed by Cr (0.085 to 0.386 μg/L, average = 0.149 μg/L), and Cd (0.001 to 0.015 μg/L, average = 0.008 μg/L). Based on the the RSD values (Pb = 87.8%, Cd = 45.2% and Cr = 41.3%), it is suggested that the antropogenic activities controls the high diversity of concentrations for heavy metal Pb relative to those of Cd and Cr. Comparing the data with the mean oceanic concentrations, only the concentrations of Pb exceed the mean oceanic level (210 folds). Therefore, the water system of Kendari Bay is severely polluted with heavy metal Pb. More management and treatment should be introduced to protect the marine environment in the study area, especially from Pb pollution.

  6. Accumulation dynamics and cellular locations of Pb, Zn and Cd in resident and transplanted Flavocetraria nivalis lichens near a former Pb-Zn mine.

    Science.gov (United States)

    Søndergaard, Jens

    2013-12-01

    Accumulation dynamics and cellular locations of lead (Pb), zinc (Zn) and cadmium (Cd) were studied in Flavocetraria nivalis lichens near the former Black Angel Pb-Zn Mine in West Greenland. Natural resident thalli were collected from four dust-contaminated sites near the mine. In addition, thalli were taken from an uncontaminated reference site and transplanted to the contaminated sites followed by a collection 1 year after. Total thalli metal contents were determined, and thalli were subjected to a sequential extraction procedure. After 1 year of transplantation, total Pb thalli contents were significantly elevated compared with initial concentrations at all sites (for Zn and Cd contents only at the two sites closest to the mine). However, transplanted thalli contained significantly less Pb (26 ± 12%), Zn (64 ± 13%) and Cd (34 ± 7 %) compared with resident thalli from these sites. Results from the sequential extraction procedure showed marked differences among Pb, Zn and Cd in the extracellular, intracellular and residual fraction. The lower total metal concentrations in transplanted compared with resident thalli at the contaminated sites were mostly due to a larger metal content bound in the residual fraction in resident thalli. In contrast, the metal content bound in the extracellular fraction were not significantly different in transplanted and resident thalli. The results indicate that extracellular-bound Pb, Zn and Cd in F. nivalis can be used as a proxy for recent (annual) atmospheric metal deposition whereas the large residual metal fraction in resident lichens indicate an accumulation of metal-containing particles in the thalli over time that includes several years of uptake.

  7. Enhanced removal of Cd(II) and Pb(II) by composites of mesoporous carbon stabilized alumina

    Science.gov (United States)

    Yang, Weichun; Tang, Qiongzhi; Wei, Jingmiao; Ran, Yajun; Chai, Liyuan; Wang, Haiying

    2016-04-01

    A novel adsorbent of mesoporous carbon stabilized alumina (MC/Al2O3) was synthesized through one-pot hard-templating method. The adsorption potential of MC/Al2O3 for Cd(II) and Pb(II) from aqueous solution was investigated compared with the mesoporous carbon. The results indicated the MC/Al2O3 showed excellent performance for Cd(II) and Pb(II) removal, the adsorption capacity reached 49.98 mg g-1 for Cd(II) with initial concentration of 50 mg L-1 and reached 235.57 mg g-1 for Pb(II) with initial concentration of 250 mg L-1, respectively. The kinetics data of Cd(II) adsorption demonstrated that the Cd(II) adsorption rate was fast, and the removal efficiencies with initial concentration of 10 and 50 mg L-1 can reach up 99% within 5 and 20 min, respectively. The pseudo-second-order kinetic model could describe the kinetics of Cd(II) adsorption well, indicating the chemical reaction was the rate-controlling step. The mechanism for Cd(II) and Pb(II) adsorption by MC/Al2O3 was investigated by X-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared spectroscopy (FTIR), and the results indicated that the excellent performance for Cd(II) and Pb(II) adsorption of MC/Al2O3 was mainly attributed to its high surface area and the special functional groups of hydroxy-aluminum, hydroxyl, carboxylic through the formation of strong surface complexation or ion-exchange. It was concluded that MC/Al2O3 can be recognized as an effective adsorbent for removal of Cd(II) and Pb(II) in aqueous solution.

  8. Biosorption of divalent Pb, Cd and Zn on aragonite and calcite mollusk shells

    Energy Technology Data Exchange (ETDEWEB)

    Du Yang; Lian Fei [Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071 (China); Zhu Lingyan, E-mail: zhuly@nankai.edu.cn [Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071 (China)

    2011-07-15

    The potential of using mollusk shell powder in aragonite (razor clam shells, RCS) and calcite phase (oyster shells, OS) to remove Pb{sup 2+}, Cd{sup 2+} and Zn{sup 2+} from contaminated water was investigated. Both biogenic sorbents displayed very high sorption capacities for the three metals except for Cd on OS. XRD, SEM and XPS results demonstrated that surface precipitation leading to crystal growth took place during sorption. Calcite OS displayed a remarkably higher sorption capacity to Pb than aragonite RCS, while the opposite was observed for Cd. However, both sorbents displayed similar sorption capacities to Zn. These could be due to the different extent of matching in crystal lattice between the metal bearing precipitate and the substrates. The initial pH of the solution, sorbent's dosage and grain size affected the removal efficiency of the heavy meals significantly, while the organic matter in mollusk shells affected the removal efficiency to a lesser extent. - Highlights: > Mollusk shells display high removal efficiency to heavy metals in contaminated water. > Surface precipitation leading to crystal growth takes place during the sorption. > Crystal structure similarity between precipitates and substrates affects the sorption. > pH, sorbent dosage and grain size of adsorbent affects the removal efficiency. > Organic matter in mollusk shells affects the removal efficiency to a less extent. - Mollusk shells display high sorption ability to heavy metals and crystal structure similarity between precipitates and substrates affects the sorption.

  9. Soil enzymatic activities and microbial community structure with different application rates of Cd and Pb

    Institute of Scientific and Technical Information of China (English)

    KHAN Sardar; CAO Qing; HESHAM Abd El-Latif; XIA Yue; HE Ji-zheng

    2007-01-01

    This study focused on the changes of soil microbial diversity and potential inhibitory effects of heavy metals on soil enzymatic activities at different application rates of Cd and Pb. The soil used for experiments was collected from Beijing and classified as endoaquepts. Pots containing 500 g of the soil with different Cd or/and Pb application rates were incubated for a period of 0, 2, 9, 12 weeks in a glasshouse and the soil samples were analyzed for individual enzymes, including catalase, alkaline phosphatase and dehydrogenase, and the changes of microbial community structure. Results showed that heavy metals slightly inhibited the enzymatic activities in all the samples spiked with heavy metals. The extent of inhibition increased significantly with increasing level of heavy metals, and varied with the incubation periods. The soil bacterial community structure, as determined by polymerase chain reaction-denaturing gradient gel electrophoresis techniques, was different in the contaminated samples as compared to the control. The highest community change was observed in the samples amended with high level of Cd. Positive correlations were observed among the three enzymatic activities, but negative correlations were found between the amounts of the heavy metals and the enzymatic activities.

  10. Kinetics of lead removal from the Cu-Pb-Fe alloy by barbotage with inert gases

    Directory of Open Access Journals (Sweden)

    B. Oleksiak

    2011-04-01

    Full Text Available Discussion of the kinetics of lead removal from the Cu-Pb-Fe alloy by barbotage with argon and helium. The values of the mass penetration coefficient for the liquid and solid phase as well as the mass transfer coefficient were calculated for the temperatures of 1 473 K and 1 548 K, and for the gas flow rate of 5,55 • 10-6, 6,94 • 10-6, 8,33 • 10-6 and 9,72 • 10-6 m • s-1.

  11. The Role of Saturated Hydrocarbon in Enrichment of Cu, Pb, Znin Kupferschiefer, Southwestern Poland

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to clarify the role of organic matter in the enrichment of base metal, 10 samples of the PermianKupferschiefer from southwestern Poland were analyzed by using microscopic and geochemical methods. The re-suts indicate that the solvent extracts have been depleted in the samples with high Cu, Pb, Zn contents. This de-pletion occurred preferably in saturated hydrocarbons. Saturated hydrocarbons served as hydrogen donor for ther-mochemical sulfate reduction (TSR). The GC traces of saturated hydrocarbon show that the depletion occurredmainly in long-chain n-alkanes.

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

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Tejbir, E-mail: dr.tejbir@gmail.com; Kaur, Sarpreet; Kaur, Parminder; Kaur, Harvinder [Department of Physics, Sri Guru Granth Sahib World University, Fatehgarh Saheb-140406, Punjab (India); Singh, Parjit S. [Department of Physics, Punjabi University, Patiala-147002, Punjab (India)

    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.

  13. Anodic stripping voltammetric determination of Zn, Pb and Cu traces in whisky samples

    Energy Technology Data Exchange (ETDEWEB)

    Barbeira, P.J.S. [Departamento de Quimica - ICEx - UFMG, Belo Horizonte, MG (Brazil); Stradiotto, N.R. [Departamento de Quimica - FFCLRP - USP, Ribeirao Preto, SP (Brazil)

    1998-07-01

    The simultaneous ``in natura`` determination of trace Zn, Pb and Cu in whisky samples by anodic stripping voltammetry (ASV), using a hanging mercury drop electrode, without previous treatment or addition of supporting electrolyte is described. The choice of an appropriate stripping voltammetric method and deposition potential minimizes the influence of the organic content and ensures a good reproducibility of the measurements. The reliability of the method was tested comparing the results with those of atomic absorption spectroscopy (AAS), with differences of about 10%. The method allows the determination of heavy metal ions in the {mu}g L{sup -1} range. (orig.) With 3 figs., 1 tab., 18 refs.

  14. Preparation of Bulky Bi(Pb)-Sr-Ca-Cu-O Superconductor by Magnetized Twin-Roll

    Science.gov (United States)

    Kawahara, Nobuaki; Kawabata, Sanemasa; Enami, Hiroyoshi; Shinohara, Toshiyuki; Hoshizaki, Hiroki; Hasegawa, Masashi; Asai, Shigeo; Imura, Toru

    1990-02-01

    A highly oriented (Bi, Pb)2Sr2Ca2Cu3Ox bulk superconductor has been prepared by magnetized twin-roll processing. In these bulks, plate-like crystal grains were highly oriented by a magnetic and mechanical force. The grain c-axes were parallel to the magnetic field and pressing directions. In fact, both critical current density (Jc) and orientation degree of the sample rolled under 2 T were higher than those of the sample rolled with no magnetic field. The magnetized twin-roll processing is effective not only in enhancing grain-orientation but also in packing to improve Jc.

  15. Heterojunction formation in (CdZn)S/CuInSe2 ternary solar cells

    Science.gov (United States)

    Ahrenkiel, R. K.; Kazmerski, L. L.; Matson, R. J.; Osterwald, C.; Massopust, T. P.; Mickelsen, R. A.; Chen, W. S.

    1983-10-01

    The electrical properties of (CdZn)S/CuInSe2 solar cells have been investigated by combining electron beam induced current measurements and capacitance-voltage measurements on the same device. In the as-grown device, the CuInSe2 is lightly doped n type. After baking to about 225 C in vacuum, the CuInSe2 converts to p type forming the heterojunction. Oxygen does not appear to be necessary for type conversion to occur.

  16. The CuInSe{sub 2}-CuGaSe{sub 2}-2CdSe system and crystal growth of the {gamma}-solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Marushko, L.P., E-mail: marushko777@mail.r [Department of General and Inorganic Chemistry, Volyn National University, Voli Ave 13, Lutsk 43009 (Ukraine); Romanyuk, Y.E. [Swiss Federal Laboratories for Materials Testing and Research, EMPA, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Piskach, L.V.; Parasyuk, O.V.; Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn National University, Voli Ave 13, Lutsk 43009 (Ukraine); Volkov, S.V.; Pekhnyo, V.I. [V.I. Vernadskii Institute for General and Inorganic Chemistry of the Ukrainian National Academy of Sciences, Palladina Ave 32-34, Kyiv 03680 (Ukraine)

    2010-08-27

    Phase equilibria in the CuInSe{sub 2}-CuGaSe{sub 2}-2CdSe system are studied using differential-thermal analysis and phase X-ray diffraction. An isothermal section of the system at 870 K, and phase diagrams of polythermal sections CuInSe{sub 2}-CuGaSe{sub 2} and 'CuCd{sub 2}InSe{sub 4}'-CuCd{sub 2}GaSe{sub 4} have been constructed. The 'CuCd{sub 2}InSe{sub 4}'-CuCd{sub 2}GaSe{sub 4} section is not quasi-binary and includes two solid solution regions with the wurtzite and sphalerite structure-types. Eleven crystals of the {gamma}-solid solutions with the sphalerite structure-type were grown by the Bridgman technique. The non-quasi-binary nature of the 'CuCd{sub 2}InSe{sub 4}'-CuCd{sub 2}GaSe{sub 4} section gives rise to compositional gradients for copper, cadmium, and gallium along the crystal growth direction so that the crystal tip is enriched with CdSe. Band gap of the grown crystals varies from 1.05 eV to {approx}1.30 eV.

  17. Acute toxicity of binary and ternary mixtures of Cd, Cu, and Zn to Daphnia magna.

    Science.gov (United States)

    Meyer, Joseph S; Ranville, James F; Pontasch, Mandee; Gorsuch, Joseph W; Adams, William J

    2015-04-01

    Standard static-exposure acute lethality tests were conducted with Daphnia magna neonates exposed to binary or ternary mixtures of Cd, Cu, and Zn in moderately hard reconstituted water that contained 3 mg dissolved organic carbon/L added as Suwannee River fulvic acid. These experiments were conducted to test for additive toxicity (i.e., the response to the mixture can be predicted by combining the responses obtained in single-metal toxicity tests) or nonadditive toxicity (i.e., the response is less than or greater than additive). Based on total metal concentrations (>90% dissolved) the toxicity of the tested metal mixtures could be categorized into all 3 possible additivity categories: less-than-additive toxicity (e.g., Cd-Zn and Cd-Cu-Zn mixtures and Cd-Cu mixtures when Cu was titrated into Cd-containing waters), additive toxicity (e.g., some Cu-Zn mixtures), or more-than-additive toxicity (some Cu-Zn mixtures and Cd-Cu mixtures when Cd was titrated into Cu-containing waters). Exposing the organisms to a range of sublethal to supralethal concentrations of the titrated metal was especially helpful in identifying nonadditive interactions. Geochemical processes (e.g., metal-metal competition for binding to dissolved organic matter and/or the biotic ligand, and possibly supersaturation of exposure waters with the metals in some high-concentration exposures) can explain much of the observed metal-metal interactions. Therefore, bioavailability models that incorporate those geochemical (and possibly some physiological) processes might be able to predict metal mixture toxicity accurately.

  18. Genotype variations in accumulation of cadmium and lead in celery (Apium graveolens L.) and screening for low Cd and Pb accumulative cultivars

    Institute of Scientific and Technical Information of China (English)

    Kun ZHANG; Jianbing WANG; Zhongyi YANG; Guorong XIN; Jiangang YUAN; Junliang XIN; Charlie HUANG

    2013-01-01

    To help reduce risks of heavy metal pollution, two pot experiments were conducted to investigate the variations, transfer potential, and stability of Cadmium (Cd) and Lead (Pb) accumulations in celery (Apium graveolens L.) and to screen for low Cd and Pb accumulative cultivars. The maximum differences in shoot Cd concentration were 4.7-fold under low-Cd exposure and 3.3-fold under high-Cd exposure. These genotype variations in Cd accumulation are sufficiently large to help reduce Cd contamination risk in soil by using the Low-Cd-Accumulative genotypes. Cd accumulation of the Low-Cd-Accumulative genotypes is significantly positive correlated with Pb accumulation. Evidence obtained proves that Cd and Pb accumulations in celery are stable and genotype-dependent at the cultivar level. The presence of high-Pb contamination in soil promoted Cd accumulation in shoots of celery. Celery is considered a species with high risks in Cd pollution and low risks in Pb pollution. Among the tested cultivars, cv. Shuanggang- kangbing (SGKB) had the lowest shoot Cd and Pb accumulating abilities, and thus is the most important material for breeding of pollution-safe cultivars (PSCs) to minimize Cd and Pb accumulations in celery.

  19. Absorbed Pb2+ and Cd2+ Ions in Water by Cross-Linked Starch Xanthate

    Directory of Open Access Journals (Sweden)

    Kai Feng

    2017-01-01

    Full Text Available A cross-linked starch xanthate was prepared by graft copolymerization of acrylamide and sodium acrylate onto starch xanthate using potassium persulfate and sodium hydrogen sulfite initiating system and N,N′-methylenebisacrylamide as a cross-linker. As this kind of cross-linked potato starch xanthate can effectively absorb heavy metal ions, it was dispersed in aqueous solutions of divalent heavy metal ions (Pb2+ and Cd2+ to investigate their absorbency by the polymer. Factors that can influence absorbency were investigated, such as the ratio of matrix to monomers, the amount of initiator and cross-linker, pH, and the concentration of metal ions. Results were reached and conclusion was drawn that the best synthetic conditions for the polymer adsorbing Pb2+ and Cd2+ were as follows: the quality ratio of matrix to monomers was 1 : 12 and 1 : 11, the amount of initiator was 2.4% and 3.2% of matrix, and the amount of cross-linker was 12 mg and 13 mg. When the initial concentration of ions was 10 mg/L, the highest quantities of adsorption of Pb2+ and Cd2+ were 47.11 mg/g and 36.55 mg/g. Adsorption mechanism was discussed by using Fourier transform infrared (FTIR spectroscopy, X-ray diffraction (XRD, scanning electron microscope (SEM, Energy Dispersive X-Ray Spectroscopy (EDS test, and adsorption kinetic simulation.

  20. Comparative studies on Pb and Cd levels in parasites of terrestrial and aquatic animals

    Energy Technology Data Exchange (ETDEWEB)

    Sures, B.; Taraschewski, H. [Univ. Karlsruhe (Germany). Zoologisches Institut-Okologie

    1995-12-31

    Several fish parasites (Acanthocephala, Cestoda, Nematoda) and organs of their respective intermediate and final hosts were analyzed for heavy metals by electrothermal atomic absorption spectrometry (ET-AAS). Pb and Cd were also quantified in the liver fluke Fasciola hepatica as well as in different organs of the large intestinal roundworm Ascaris suum. The levels of these heavy metals in the parasites were compared to those of muscle, liver, kidney and intestine of the respective definitive hosts cattle and swine obtained from a slaughter house. Most parasites accumulated significantly higher levels of metals than their final hosts. This was most conspicuous in acanthocephalans which contained up to 3 {times} 10{sup 3} fold more lead than the muscle of their fish hosts and up to 1.1 {times} 10{sup 4} more lead than the water surrounding the fish. In these helminths cadmium was enriched up to 400 fold compared to the muscle of the fish and up to 2.7 {times} 10{sup 4} compared to the water. In contrast to the accumulation capacity of adult acanthocephalans their larvae contained about 30 to 180 times less Pb and Cd. Thus, the predominant accumulation of both metals appears in the adult worms. The cestodes of fish and the liver flukes of cattle accumulated the metals up to 200 fold compared to the muscle of their hosts. The nematodes did not contain higher levels of the metals than their hosts. Thus, parasites, especially acanthocephalans, seem to be sensitive bioindicators of Pb and Cd in their environments.

  1. Elevated CO2 affects secondary metabolites in Robinia pseudoacacia L. seedlings in Cd- and Pb-contaminated soils.

    Science.gov (United States)

    Jia, Xia; Zhao, Yonghua; Liu, Tuo; Huang, Shuping

    2016-10-01

    Secondary metabolites play important roles in plant interactions with the environment. The co-occurrence of heavy metal contamination of soils and rising atmospheric CO2 has important effects on plant. It is important to explore the ways in which production of plant secondary metabolites is affected by heavy metals under elevated atmospheric CO2. We examined the effects of elevated CO2 on secondary metabolite contents in Robinia pseudoacacia seedlings grown in Cd- and lead (Pb)-contaminated soils. The increase in secondary metabolites was greater under Cd + Pb exposure than under exposure to individual metals regardless of elevated CO2 with the exception of condensed tannins in leaves and total alkaloids in stems. Except for phenolic compounds and condensed tannins, elevated CO2 was associated with increased secondary metabolite contents in leaves and stems of plants exposed to Cd, Pb, and Cd + Pb compared to plants exposed to ambient CO2 + metals. Changes in saponins in leaves and alkaloids in stems were greater than changes in the other secondary metabolites. Significant interactive effects of CO2, Cd, and Pb on secondary metabolites were observed. Saponins in leaves and alkaloids in stems were more sensitive than other secondary metabolites to elevated CO2 + Cd + Pb. Elevated CO2 could modulate plant protection and defense mechanisms in R. pseudoacacia seedlings exposed to heavy metals by altering the production of secondary metabolites. The increased Cd and Pb uptake under elevated CO2 suggested that R. pseudoacacia may be used in the phytoremediation of heavy metal-contaminated soils under global environmental scenarios.

  2. Advanced Architecture for Colloidal PbS Quantum Dot Solar Cells Exploiting a CdSe Quantum Dot Buffer Layer.

    Science.gov (United States)

    Zhao, Tianshuo; Goodwin, Earl D; Guo, Jiacen; Wang, Han; Diroll, Benjamin T; Murray, Christopher B; Kagan, Cherie R

    2016-09-22

    Advanced architectures are required to further improve the performance of colloidal PbS heterojunction quantum dot solar cells. Here, we introduce a CdI2-treated CdSe quantum dot buffer layer at the junction between ZnO nanoparticles and PbS quantum dots in the solar cells. We exploit the surface- and size-tunable electronic properties of the CdSe quantum dots to optimize its carrier concentration and energy band alignment in the heterojunction. We combine optical, electrical, and analytical measurements to show that the CdSe quantum dot buffer layer suppresses interface recombination and contributes additional photogenerated carriers, increasing the open-circuit voltage and short-circuit current of PbS quantum dot solar cells, leading to a 25% increase in solar power conversion efficiency.

  3. Experimental and theoretical spectroscopic studies of Ag-, Cd- and Pb-sodalite

    Science.gov (United States)

    Mikuła, A.; Król, M.; Koleżyński, A.

    2016-12-01

    Synthetic sodalite structures containing silver, cadmium and lead cations have been obtained and structurally identified. In order to examine the changes in sodalite spectra envelope resulting from the substitution of initial sodium cations by Ag+, Cd2+ and Pb2+, a series of theoretical sodalite model structures with various Me/Na ratio and different anions have been prepared. Based on ab initio calculations and experimental results, it has been determined how the type and amount of both extra framework cations and anions affect the vibrational spectra and structural properties of sodalite. Additionally, an attempt to identified of bands associated with the individual cations and anions vibration has been undertaken.

  4. Physical Property Characterization of Pb2+-Doped CdS Nanofilms Deposited by Chemical-Bath Deposition at Low Temperature

    Science.gov (United States)

    Díaz-Reyes, J.; Contreras-Rascón, J. I.; Galván-Arellano, M.; Arias-Cerón, J. S.; Gutiérrez-Arias, J. E. M.; Flores-Mena, J. E.; Morín-Castillo, M. M.

    2016-08-01

    Pb2 +-doped CdS nanofilms are prepared using the growth technique chemical bath deposition (CBD) under optimum conditions lead acetate at the reservoir temperature of 20 ± 2 °C. The Pb2+ molar concentration was in the range 0.0 ≤ x ≤ 0.19.67, which was determined by energy-dispersive X-ray spectroscopy (EDS). The X-ray diffraction results show that the films are of PbS-CdS composites with individual CdS and PbS planes. The X-ray diffraction (XRD) analysis and Raman scattering reveal that CdS-deposited films showed the zincblende (ZB) crystalline phase. The average grain size of the CdS films ranged from 1.21 to 6.67 nm that was determined by the Debye-Scherrer equation from ZB (111) direction, and it was confirmed by high-resolution transmission electron microscopy (HRTEM). Raman scattering shows that the lattice dynamics is characteristic of bimodal behaviour and the multipeaks adjust of the first optical longitudinal mode for the Pb2+-doped CdS denotes the Raman shift of the characteristic peak in the range of 305-298 cm-1 of the CdS crystals, which is associated with the lead ion incorporation. The films exhibit three direct bandgaps, ~2.44 eV attributed to CdS; the other varies continuously from 1.67 to 1.99 eV and another disappears as Pb2+ molar fraction increases.

  5. Spray Deposition of High Quality CuInSe2 and CdTe Films: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, C. J.; van Hest, M.; Miedaner, A.; Leisch, J.; Hersh, P.; Nekuda, J.; Ginley, D. S.

    2008-05-01

    A number of different ink and deposition approaches have been used for the deposition of CuInSe2 (CIS), Cu(In,Ga)Se2 (CIGS), and CdTe films. For CIS and CIGS, soluble precursors containing Cu, In, and Ga have been developed and used in two ways to produce CIS films. In the first, In-containing precursor films were sprayed on Mo-coated glass substrates and converted by rapid thermal processing (RTP) to In2Se3. Then a Cu-containing film was sprayed down on top of the In2Se3 and the stacked films were again thermally processed to give CIS. In the second approach, the Cu-, In-, and Ga-containing inks were combined in the proper ratio to produce a mixed Cu-In-Ga ink that was sprayed on substrates and thermally processed to give CIGS films directly. For CdTe deposition, ink consisting of CdTe nanoparticles dispersed in methanol was prepared and used to spray precursor films. Annealing these precursor films in the presence of CdCl2 produced large-grained CdTe films. The films were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). Optimized spray and processing conditions are crucial to obtain dense, crystalline films.

  6. Crystal structure and charge localization in Pb2Sr2Y1-xCaxCu3O8 for x=0.0-0.5

    DEFF Research Database (Denmark)

    Jørgensen, J.-E.; Andersen, N.H.

    1993-01-01

    Neutron powder diffraction studies of Pb2Sr2Y1-xCaxCu3O8 samples for x = 0.0-0. 5 have shown that Ca doping causes a positive charge transfer to the CuO2 as well as to the PbO layers. The bond-valency sum for the Cu ions in the CuO2 layer increases as a function of x, while the bond-valency sum f...

  7. Energy Parameters of Interfacial Layers in Composite Systems: Graphene – (Si, Cu, Fe, Co, Au, Ag, Al, Ru, Hf, Pb and Semiconductor (Si,Ge – (Fe, Co, Cu, Al, Au, Cr, W, Pb

    Directory of Open Access Journals (Sweden)

    B.P. Koman

    2015-12-01

    Full Text Available On the basis of the non-equilibrium thermodynamics relations and the surface physics phenomena we calculate adhesion and energy parameters to characterize the interfacial interactions in graphene – (Si, Cu, Fe, Co, Au, Ag, Al, Ru, Hf, Pb and semiconductor (Si, Ge – (Fe, Co, Cu, Al, Au, Cr, W, Pb systems. We analyze trends of the interfacial energy, interfacial tension, work of adhesion and the energy of adhesive bonds on the contacting element’s atomic number in the periodic table and on the electronegativity difference of interacting elements. Thus, this work provides theoretical basis for the development of new composite materials.

  8. Comparison Studies of Dielectric and AC Conduction of PbPc and CuPc Thin Films

    Directory of Open Access Journals (Sweden)

    S. Sivamalar

    2012-08-01

    Full Text Available The thin film of Lead Phthalocyanine (PbPc and Copper Phthalocyanine (CuPc on glass are prepared by Vacuum deposition method. Deposition of PbPc and CuPc on pre-cleaned glass substrates under the pressure of 10-6 Torr are achieved by slowly varying current of 20 Volt. The rate of evaporation is properly controlled and maintained constant during all the evaporations. The thicknesses of the films are 150 nm, 300 nm and 450 nm on glass substrate. Dielectric and AC conduction studies of Lead Phthalocyanine and Cupper Phthalocyanine thin films have been studied. The variations of capacitance with frequency at different, permittivity with temperature, capacitance with temperature and ac conductance with frequency at different temperatures of PbPc and CuPc have been studied. The activation energies have been determined from the slope of 1000/T vs. log Gp curves at different frequencies (where Gp= -Eg/RT.

  9. Fine scale characterization of surface/subsurface and nanosized debris particles on worn Cu-10 % Pb nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Amit S.; Biswas, Krishanu, E-mail: kbiswas@iitk.ac.in; Basu, Bikramjit [Indian Institute of Technology Kanpur, Department of Materials Science and Engineering (India)

    2013-05-15

    The identification of the damage mechanisms involved in the wear process demands the finer scale characterization of the surface, as well as the subsurface region of the wear scar region, and to this end, this article discusses the results obtained with Cu-10 wt% Pb-based metallic nanocomposites using a host of characterization techniques, including transmission electron microscopy and ion milling microscopy. Apart from finer scale characterization to understand deformation and cracking during the wear process, X-ray photoelectron spectroscopy analysis of wear debris confirms the occurrence of oxidation of Pb phase to Pb{sub 3}O{sub 4}. In order to understand the role of oxides on friction and wear, sliding wear tests in argon were also carried out and such tests did not result in the formation of any tribo-oxides, as confirmed using electron probe microanalysis. Conclusively, oxidative wear is attributed as the dominant wear mechanism in ambient conditions for Cu-10 wt% Pb composite.

  10. Cu-doped ZnO nanoporous film for improved performance of CdS/CdSe quantum dot-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Myeong-Soo; Son, Min-Kyu; Kim, Soo-Kyoung; Park, Songyi; Prabakar, Kandasamy; Kim, Hee-Je, E-mail: heeje@pusan.ac.kr

    2014-11-03

    Copper (Cu) doped zinc oxide (ZnO) powders were synthesized by co-precipitation method with different at% (0 and 0.5 at%) of Cu dopant. Cu-doped ZnO nanoporous (NP) films were fabricated to enhance the performance of the ZnO based cadmium sulfide (CdS) and cadmium selenide (CdSe) quantum dot-sensitized solar cells (QDSSCs). The existence of Cu ions in the Cu-doped ZnO NP film was detected by X-ray fluorescence. The surface morphology, microstructure and crystal structure of Cu-doped ZnO NP films were analyzed by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The optical property of CdS/CdSe co-sensitized Cu-doped ZnO NP film was studied by UV–vis absorption spectroscopy. The photovoltaic performance and electrical property of Cu-doped ZnO CdS/CdSe QDSSCs were studied by current–voltage characteristic curves and electrochemical impedance spectroscopy under air mass 1.5 condition. As a result, short circuit current density and fill factor increased from 9.074 mA/cm{sup 2} and 0.403 to 9.865 mA/cm{sup 2} and 0.427 respectively, based on the enhanced absorbance and electron transport by Cu-doping. This led to the increasing light conversion efficiency from 2.27% to 2.61%. - Highlights: • Cu-doped ZnO powders were synthesized by co-precipitation method. • Cu-doped ZnO nanoporous films with high crystallinity were uniformly deposited. • Absorbance of Cu-doped ZnO nanoporous film was enhanced. • Electron conductivity of Cu-doped ZnO nanoporous film was enhanced. • Performance of Cu-doped ZnO CdS/CdSe QDSSC was improved.

  11. Electrochemical method for improving the spectral response of CdS/Cu 2S heterojunctions

    Science.gov (United States)

    Garcia-Camarero, E.; Arjona, F.; Fatas, E.

    The effect on the stoichiometry of a copper sulphide electrode of short-circuiting the Cu/Cu aq2+/Cu 2-δS/In galvanic cell for different times has been studied. This treatment has been carried out on the copper sulphide layer of CdS/Cu 2S solar cells prepared by different methods. The resulting changes of the spectral short circuit current and the I-V characteristics of the cells have been recorded. Remarkable increases in open circuit voltage, short circuit current, and fill factor have been observed as a consequence of any transformation that increases the proportion of copper in the copper sulphide films. Thus, this treatment could be a suitable method of improving the efficiency of CdS/Cu 2S solar cells.

  12. Phase field simulation of monotectic transformation for liquid Ni-Cu-Pb alloys

    Institute of Scientific and Technical Information of China (English)

    LUO BingChi; WANG HaiPeng; WEI BingBo

    2009-01-01

    Based on the subregular solution model, the liquid phase separation of ternary (NixCu100-x)50Pb50monotectic alloys is simulated by the phase field method. It is found that if the surface segregation potential is not incorporated, the dynamic morphologies of alloy melt show a transition from disperse microstructure into bicontinuous microstructure with the increase of fluidity parameter. When the sur-face segregation potential is coupled, Pb-rich phase migrates preferentially to the surface of the liquid alloy, and the Ni-rich phase depends on the Pb-rich phase to nucleate. With the extension of the phase separation time, the surface layer is formed through coagulation and growth, and its thickness gradu-ally increases. The Ni-rich phase migrates to the central part, and finally a two-layer core-shell micro-structure is produced. The concentration in the surface layer fluctuates more conspicuously than that inside the bulk phase, which subsequently transfers from the surface to the interior by a wave. The fluid field near the liquid-liquid interface is strong at the beginning of phase separation, and reduces later on. The surface segregation is essential to the formation of the surface layer, concentration profile variation, fluid field distribution and phase separation morphology.

  13. Sharpness-induced energy shifts of quantum well states in Pb islands on Cu(111)

    Science.gov (United States)

    Chan, Wen-Yuan; Lu, Shin-Ming; Su, Wei-Bin; Liao, Chun-Chieh; Hoffmann, Germar; Tsai, Tsong-Ru; Chang, Chia-Seng

    2017-03-01

    We elucidate that the tip sharpness in scanning tunneling microscopy (STM) can be characterized through the number of field-emission (FE) resonances. A higher number of FE resonances indicates higher sharpness. We observe empty quantum well (QW) states in Pb islands on Cu(111) under different tip sharpness levels. We found that QW states observed by sharper tips always had lower energies, revealing negative energy shifts. This sharpness-induced energy shift originates from an inhomogeneous electric field in the STM gap. An increase in sharpness increases the electric field inhomogeneity, that is, enhances the electric field near the tip apex, but weakens the electric field near the sample. As a result, higher sharpness can increase the electronic phase in vacuum, causing the lowering of QW state energies. Moreover, the behaviors of negative energy shift as a function of state energy are entirely different for Pb islands with a thickness of two and nine atomic layers. This thickness-dependent behavior results from the electrostatic force in the STM gap decreasing with increasing tip sharpness. The variation of the phase contributed from the expansion deformation induced by the electrostatic force in a nine-layer Pb island is significantly greater, sufficient to effectively negate the increase of electronic phase in vacuum.

  14. Pathways toward higher performance CdS/CdTe devices: Te exposure of CdTe surface before ZnTe:Cu/Ti contacting

    Energy Technology Data Exchange (ETDEWEB)

    Gessert, T.A., E-mail: tim.gessert@nrel.gov; Burst, J.M.; Wei, S.-H.; Ma, J.; Kuciauskas, D.; Rance, W.L.; Barnes, T.M.; Duenow, J.N.; Reese, M.O.; Li, J.V.; Young, M.R.; Dippo, P.

    2013-05-01

    Many studies of thin-film CdS/CdTe photovoltaic devices have suggested that performance may be improved by reducing recombination due to Te-vacancy (V{sub Te}), Te antisite (Te{sub Cd}), or Te-interstitial (Te{sub i}) defects. Although formation of these intrinsic defects is likely influenced by CdTe deposition parameters, it may be also coupled to the formation of beneficial cadmium vacancy (V{sub Cd}) defects. In this study, we expose the CdTe surface to Te vapor prior to ZnTe:Cu/Ti contact-interface formation with the goal of reducing V{sub Te} without significantly reducing V{sub Cd}. Initial results show that when this modified contact is used on a CdCl{sub 2}-treated CdS/CdTe device, poorer device performance results. This suggests two things: First, the amount of free-Te available during contact formation (either from chemical etching or Cu{sub x}Te or ZnTe deposition) may be a more important parameter to device performance than previously appreciated. Second, if processes have been used to reduce the effect of V{sub Te} (e.g., oxygen and chlorine additions), adding even a small amount of Te may produce detrimental defects. - Highlights: ► Te exposure of CdS/CdTe back contact reduces device performance. ► Field strength and minority carrier lifetime reduced. ► Calculations suggest formation of Te on Cd antisite defect.

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

    Science.gov (United States)

    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

  16. Fabrication of CdS/CdTe solar cells with transparent p-type conductive BaCuSeF back contact

    Science.gov (United States)

    Yamamoto, Koichi; Sakakima, Hiroshi; Ogawa, Yohei; Hosono, Aikyo; Okamoto, Tamotsu; Wada, Takahiro

    2015-08-01

    BaCuSeF films were applied to CdS/CdTe solar cells as back electrodes. The interfaces between the CdTe and BaCuSeF layers in the CdS/CdTe solar cells with BaCuSeF back contact deposited at substrate temperatures (TS) of 200 and 300 °C were analyzed by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). We clearly observed many dislocations in the CdTe layer in the CdS/CdTe solar cell with the BaCuSeF layer deposited at TS = 300 °C. We also observed a reaction layer of Cu2.72Te2 between the BaCuSeF and CdTe layers in both solar cells. We concluded that (1) the substrate temperature for the pulsed laser deposition of the BaCuSeF layer and (2) the interface between the CdTe and BaCuSeF layers are important factors for the performance of the CdTe solar cells. We obtained high conversion efficiency of 8.31% for a solar cell with a BaCuSeF layer deposited at TS = 200 °C on a CdTe surface etched in a NH3 aqueous solution. The highest conversion efficiency of 9.91% was obtained for a solar cell with a CdTe surface etched in a bromide-bromate solution.

  17. Modeling Cu Migration in CdTe Solar Cells Under Device-Processing and Long-Term Stability Conditions (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Teeter, G.; Asher, S.

    2008-05-01

    An impurity migration model for systems with material interfaces is applied to Cu migration in CdTe solar cells. In the model, diffusion fluxes are calculated from the Cu chemical potential gradient. Inputs to the model include Cu diffusivities, solubilities, and segregation enthalpies in CdTe, CdS and contact materials. The model yields transient and equilibrium Cu distributions in CdTe devices during device processing and under field-deployed conditions. Preliminary results for Cu migration in CdTe PV devices using available diffusivity and solubility data from the literature show that Cu segregates in the CdS, a phenomenon that is commonly observed in devices after back-contact processing and/or stress conditions.

  18. Modeling Cu Migration in CdTe Solar Cells Under Device-Processing and Long-Term Stability Conditions: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Teeter, G.; Asher, S.

    2008-05-01

    An impurity migration model for systems with material interfaces is applied to Cu migration in CdTe solar cells. In the model, diffusion fluxes are calculated from the Cu chemical potential gradient. Inputs to the model include Cu diffusivities, solubilities, and segregation enthalpies in CdTe, CdS and contact materials. The model yields transient and equilibrium Cu distributions in CdTe devices during device processing and under field-deployed conditions. Preliminary results for Cu migration in CdTe photovoltaic devices using available diffusivity and solubility data from the literature show that Cu segregates in the CdS, a phenomenon that is commonly observed in devices after back-contact processing and/or stress conditions.

  19. Influence of Pb-rich phases of precursor powder on microstructural evolution in the silver-sheathed (Bi,Pb)2Sr2Ca2Cu3Ox superconducting tapes

    DEFF Research Database (Denmark)

    Chen, X.P.; Grivel, Jean-Claude; Li, M.Y.;

    2010-01-01

    The influence of Pb-rich phases of precursor powder on microstructural evolution during the first heat treatment of the silver-sheathed (Bi,Pb)2Sr2Ca2Cu3Ox ((Bi,Pb)-2223/Ag) superconducting tapes was studied by means of in situ synchrotron X-ray diffraction. Three monofilament tapes were fabricat...

  20. Optical and structural properties of CdS:Pb{sup 2+} nano crystals

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, R.; Portillo, O; Chaltel, L.; Zamora, M.; Lazcano, M.; Hernandez, G. [Universidad Autonoma de Puebla, Facultad de Ciencias Quimicas, Materials Science Laboratory, Apdo. Postal 1067, 72001 Puebla, Puebla (Mexico); Chavez, M.; Juarez, H.; Pacio, M.; Rubio, E., E-mail: osporti@yahoo.mx [Universidad Autonoma de Puebla, CIDS-ICUAP, 72001 Puebla, Puebla (Mexico)

    2015-07-01

    The goal of this work is to study the effects of doping on structural, morphological and optical properties of CdS thin films as a function of Pb{sup 2+} concentration. Thus, nanoparticles were synthesized by chemical bath and a thickness decrease of ∼575-200 nm range was observed. In Fourier transform infrared spectroscopy, all the samples showed a sharp stretching mode observed at ∼1384 cm{sup -1} corresponding to the vibration mode of CO{sub 3}{sup -2}. X-ray diffraction studies show that the size of crystallites is in the ∼33-12 nm range. The peaks belonging to primary phase are identified at the 2θ = 26.5 grades and 2θ = 26.00 grades, corresponding to CdS and Pb S respectively. Thus, a shift in maximum intensity peak from 2θ = 26.4 to 28.2 grades is observed. Likewise peaks at 2θ = 13.57, 15.91 grades correspond to lead perchlorate thiourea. The optical, absorption, and transmission properties of the films were determined by UV-Vis spectrophotometry, optical energy gap was found to range from 2.1 to 2.4 eV. Raman spectroscopy on doped films showed a shifting of these modes that can be attributed to strain, stress effects, defects, phonon confinement, and variation in phonon relaxation with grain size. (Author)

  1. Quantifying Pb and Cd complexation by alginates and the role of metal binding on macromolecular aggregation.

    Science.gov (United States)

    Lamelas, Cristina; Avaltroni, Fabrice; Benedetti, Marc; Wilkinson, Kevin J; Slaveykova, Vera I

    2005-01-01

    The Pb and Cd binding capacity of alginates were quantified by the determination of their complex stability constants and the concentration of complexing sites using H+, Pb2+, or Cd2+ selective electrodes in both static and dynamic titrations. Centrifugation filter devices (30 kDa filter cutoff), followed by inductively coupled plasma mass spectrometry (ICP-MS) measurements of lead or cadmium in the filtrates, were used to validate the results. The influence of ionic strength, pH, and the metal-to-alginate ratio was determined for a wide range of metal concentrations. Because of their polyelectrolytic properties, alginates may adopt different conformations depending on the physicochemistry of the medium, including the presence of metals. Therefore, molecular diffusion coefficients of the alginate were determined by fluorescence correlation spectroscopy under the same conditions of pH, ionic strength, and metal-to-alginate ratios that were used for the metal binding studies. The complexation and conformational properties of the alginate were related within the framework of the nonideal competitive adsorption isotherm (NICA) combined with a Donnan approach to account for both intrinsic and electrostatic contributions.

  2. Monte Carlo simulations of morphological transitions in PbTe/CdTe immiscible material systems

    Science.gov (United States)

    Mińkowski, Marcin; Załuska-Kotur, Magdalena A.; Turski, Łukasz A.; Karczewski, Grzegorz

    2016-09-01

    The crystal growth of the immiscible PbTe/CdTe multilayer system is analyzed as an example of a self-organizing process. The immiscibility of the constituents leads to the observed morphological transformations such as an anisotropy driven formation of quantum dots and nanowires and to a phase separation at the highest temperatures. The proposed model accomplishes a bulk and surface diffusion together with an anisotropic mobility of the material components. We analyze its properties by kinetic Monte Carlo simulations and show that it is able to reproduce all of the structures observed experimentally during the process of the PbTe/CdTe growth. We show that all of the dynamical processes studied play an important role in the creation of zero-, one-, two-, and, finally, three-dimensional structures. The shape of the structures that are grown is different for relatively thick multilayers, when the bulk diffusion cooperates with the anisotropic mobility, as compared to the annealed structures for which only the isotropic bulk diffusion decides about the process. Finally, it is different again for thin multilayers when the surface diffusion is the most decisive factor. We compare our results with the experimentally grown systems and show that the proposed model explains the diversity of observed structures.

  3. Heavy metal (Cd, Pb, Zn) and metalloid (As) content in raptor species from Galicia (NW Spain).

    Science.gov (United States)

    Pérez-López, Marcos; Hermoso de Mendoza, María; López Beceiro, Ana; Soler Rodríguez, Francisco

    2008-05-01

    As top consumers in food chains, birds of prey forage over large geographical areas and so might be expected to accumulate environmental contaminants which are distributed in the environment. These wild animals can offer opportunities to detect and assess the toxicological effects of different inorganic elements on terrestrial ecosystems. In this study, different raptor species, both diurnal and nocturnal, were investigated for heavy metal (Pb, Cd and Zn) and As concentrations in liver samples, with the aim of furnishing indirect information concerning contamination of their habitats. Dead animals were obtained with the special collaboration of the Wildlife Rehabilitation Centres from Galicia (NW Spain). After sample wet digestion, metal analysis was performed by inductively coupled plasma-mass spectrometry (ICP-MS). Hepatic concentrations of Zn and As, respectively, situated on the interval 147-298 and 1.21-6.88 ppm (dry weight, dw), could be considered as indicative of low and background amounts of both elements, with no ecotoxicological concern. Nevertheless, with respect to Pb, some diurnal raptors showed hepatic concentrations above the considered threshold value (6 ppm dw) for sublethal or lethal toxicity, the species with the highest hepatic level corresponding to a common buzzard (>18 ppm, dw). Similarly, nocturnal raptors exceeded the threshold value for Cd (3 ppm dw), with a maximum corresponding to an individual barn owl (39 ppm, dw). In both cases, although concentrations could not be directly related to lethal effect, they might constitute a serious environmental factor affecting the survival of the considered populations.

  4. Subcellular localization of several heavy metals of Hg,Cd and Pb in human liver

    Institute of Scientific and Technical Information of China (English)

    CHEN Chunying; ZHANG Peiqun; CHAI Zhifang

    2005-01-01

    Liver, as an important metabolic and detoxicological organ of human body, can be used as a good bioindicator for evaluating body burden of environmental pollutants. Its elemental contents and their chemical forms are closely related to the status of human health and disease. In this paper, the liver samples collected from normal subjects were separated to different subcellular fractions of nuclei, mitochondria, lysosome, microsome and cytosol by differential centrifugation. Then their concentrations of heavy metals of As, Pb, Cd, and Hg were determined by atomic absorption and atomic fluorescent spectroscopy. Our results show no significant difference with literature ones when comparing their gross concentrations. In the case of their subcellular distribution, the Hg concentrations are higher in mitochondrial, microsomal and cytosolic fractions; the Cd concentrations are higher in cytosolic and mitochondrial fractions, while As highest in nuclear fraction. The highest concentration of Pb is found in microsomal fraction with similarity to Fe. Mercury in liver is mainly in the form of inorganic, and methylmercury ranged from 9% to 50% with the average value of 20.9%(13.3%. These results indicate that the cellular distribution and the accumulated target organelles are quite different among these heavy metals, which suggest their various pathways and toxic mechanism in vivo.

  5. Optical band gap energy and ur bach tail of CdS:Pb2+ thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, M.; Juarez, H.; Pacio, M. [Universidad Autonoma de Puebla, Instituto de Ciencias, Centro de Investigacion en Dispositivos Semiconductores, Av. 14 Sur, Col. Jardines de San Manuel, Ciudad Universitaria, Puebla, Pue. (Mexico); Gutierrez, R.; Chaltel, L.; Zamora, M.; Portillo, O. [Universidad Autonoma de Puebla, Facultad de Ciencias Quimicas, Laboratorio de Materiales, Apdo. Postal 1067, 72001 Puebla, Pue. (Mexico); Mathew, X., E-mail: osporti@yahoo.mx [UNAM, Instituto de Energias Renovables, Temixco, Morelos (Mexico)

    2016-11-01

    Pb S-doped CdS nano materials were successfully synthesized using chemical bath. Transmittance measurements were used to estimate the optical band gap energy. Tailing in the band gap was observed and found to obey Ur bach rule. The diffraction X-ray show that the size of crystallites is in the ∼33 nm to 12 nm range. The peaks belonging to primary phase are identified at 2θ = 26.5 degrees Celsius and 2θ = 26.00 degrees Celsius corresponding to CdS and Pb S respectively. Thus, a shift in maximum intensity peak from 2θ = 26.4 to 28.2 degrees Celsius is clear indication of possible transformation of cubic to hexagonal phase. Also peaks at 2θ = 13.57, 15.9 degrees Celsius correspond to lead perchlorate thiourea. The effects on films thickness and substrate doping on the band gap energy and the width on tail were investigated. Increasing doping give rise to a shift in optical absorption edge ∼0.4 eV. (Author)

  6. Polyhydroxyl-aluminum pillaring improved adsorption capacities of Pb2+ and Cd2+ onto diatomite

    Institute of Scientific and Technical Information of China (English)

    朱健; 王平; 雷明婧; 张伟丽

    2014-01-01

    In order to greatly improve adsorption capacity, the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis. The scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), surface area and porosity analyzer and micro-electrophoresis were used to determine pore structure and surface property.The pillared diatomite attaining the optimal adsorption densities (qe) of Pb2+ and Cd2+ was synthesized with the following conditions: Addition of pillaring solution containing Al3+-oligomers with a concentration range of 0.1-0.2 mol/L to a suspension containing Na+-diatomite to obtain the required Al/diatomite ratio of 10 mmol/g; synthesis temperature of 80 °C for 120 min; aging at a temperature of 105 °C for 16 h. The adsorption capacities of Pb2+ and Cd2+ on pillared diatomite increase by 23.79% and 27.36% compared with natural diatomite, respectively. The surface property of pillared diatomite is more favorable for ion adsorption than natural diatomite. The result suggests that diatomite can be modified by pillaring with polyhydroxyl-aluminum to improve its adsorption properties greatly.

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

    Science.gov (United States)

    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

  8. Efficiency of Chitosan for the Removal of Pb (II), Fe (II) and Cu (II) Ions from Aqueous Solutions

    OpenAIRE

    Soheil Sobhanardakani; Raziyeh Zandipak; Hassan Parvizimosaed; Arash Javanshir Khoei; Mehran Moslemi; Mahsa Tahergorabi; Seyed Mehdi Hosseini; Parisa Delfieh

    2014-01-01

    Background: Heavy metals have been recognized as harmful environmental pollutant known to produce highly toxic effects on different organs and systems of both humans and animals. The aim of this paper is to evaluate the adsorption potential of chitosan for the removal of Pb(II), Fe(II) and Cu(II) ions from aqueous solutions. Methods: This study was conducted in laboratory scale. In this paper chitosan has been used as an adsorbent for the removal of Pb(II), Fe(II) and Cu(II) from aqueous s...

  9. One pot synthesis of Pb S/Cu{sub 2}S core-shell nanoparticles and their optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, T.; Gomez, I., E-mail: maria.gomez@uanl.edu.mx [Universidad Autonoma de Nuevo Leon, Facultad de Ciencias Quimicas, Laboratorio de Materiales, Pedro de Alba, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon (Mexico)

    2014-07-01

    The synthesis of Pb S/Cu{sub 2}S core-shell nanoparticles with emission on the visible range and with improved luminescence properties was carried out by the colloidal solution-phase growth method by using simple stabilizers such as trisodium citrate and 3-mercaptopropionic acid. The core shell arrangement for particles with different crystalline structure was achieved, in addition this is the first report related to the synthesis Pb S/C{sub 2}S core-shell system. The data obtained from absorption spectra, Pl spectra, and HRTEM image provided direct proof of the formation of Pb S core with size around 11 nm and Cu{sub 2}S shell of 5 nm thickness. According to the UV-vis absorption and Pl spectrum the optical characteristics observed in the synthesized material correspond to a Pb S/Cu{sub 2}S system that has a higher confinement effect than the pure Pb S nanoparticles. The Q Y was improved in 15% from Pb S/C{sub 2}S nanoparticles. The estimated band (Homo-Lumo) alignment determined by C V measurements corresponds to a type-I core shell arrangement. The synthesized material was studied with different techniques. The size and dispersion of the particles were determined by ultraviolet-visible (UV-Vis), photoluminescence and quantum yield, Dynamic Light Scattering method and X-ray diffraction with copper radiation (λ = 0.15418 nm). (Author)

  10. Study of Cu-related Defect States in Single-crystal CdTe

    Science.gov (United States)

    Corwine, Caroline; Sites, James; Gessert, Timothy; Metzger, Wyatt; Dippo, Pat; Duda, Anna

    2003-10-01

    We have studied single-crystal CdTe using low-temperature photoluminescence (PL) in an effort to understand the effects of copper on the deep levels, as well as the effect of a bromine methanol (BrMe) etch on subsequent copper diffusion into CdTe. In present polycrystalline CdS/CdTe solar cell technology, the use of a back contact that contains Cu is necessary to produce high-efficiency cells. However, it is not generally understood why Cu is necessary for these devices to function well. In order to obtain further advances in the efficiencies of these solar cells, it is important to know how the back contact process may affect the defect states in CdTe. PL is one tool used to study defect states. However, before PL can be used effectively for polycrystalline CdTe solar cells, relevant spectral features first must be interpreted for single-crystal CdTe. All PL in this study was taken at 4.5 K. We report on PL peaks at 1.40 and 1.45 eV, which are seen only after Cu is diffused into single-crystal CdTe.

  11. Au/Cu2Te/CdTe/CdS/TCO/Glass Solar Cells with CdIn2O4 Obtained by Sol-Gel as TCO

    Directory of Open Access Journals (Sweden)

    J. Márquez Marín

    2014-01-01

    Full Text Available An Au/Cu2Te/CdTe/CdS/TCO/glass heterostructure based superstrate solar cells with 2.5 mm2 of area, where the CdTe layer was prepared by means of closed spaced sublimation (CSS and the CdS by chemical bath, reached an efficiency η value of 12.1%. As transparent conductive oxide (TCO, a thin film of cadmium-indium oxide (CdIn2O4:CIO, obtained by sol-gel technique, was used. A systematic optimization of the thermal activation of the CdTe/CdS/CIO central part of the device with a CdCl2 vapor ambient made the conversion efficiency of the Au/Cu2Te/CdTe/CdS/CIO/glass heterostructure reaches 9.94% for the CdTe layer with thickness of 1.8 μm. This efficiency was reached only through an open circuit voltage VOC optimization. A maximum η of 12.1% was reached with the established procedure of optimization and when the CdTe layer thickness was increased to 3.1 ± 0.05 μm. The substitution of CIO by commercial ITO provoked in the cell a decrease of η from 12.1% to 7.2%, both devices prepared under the same conditions. Starting from these results, we can say that CIO was a better TCO than commercial ITO in our solar cell, with the advantage that CIO was obtained by sol-gel, which is a simple and economical technique.

  12. Prosopis juliflora--a green solution to decontaminate heavy metal (Cu and Cd) contaminated soils.

    Science.gov (United States)

    Senthilkumar, P; Prince, W S P M; Sivakumar, S; Subbhuraam, C V

    2005-09-01

    Soil and plant samples (root and shoot) of Prosopis juliflora were collected in the vicinity of metal based foundry units in Coimbatore and assessed for their heavy metal content (Cu and Cd) to ascertain the use of P. juliflora as a green solution to decontaminate soils contaminated with Cu and Cd. The results showed that Cu and Cd content was much higher in plant components compared to their extractable level in the soil. Furthermore, there exist a strong correlation between the distance of the sources of industrial units and accumulation of heavy metals in plants. Accumulation of Cd in roots is comparatively higher than that of shoots. However, in case of Cu no such clear trend is seen. Considering the accumulation efficiency and tolerance of P. juliflora to Cd and Cu, this plant can be explored further for the decontamination of metal polluted soils. On the other hand, in view of heavy metal accumulate the practice of providing foliage and pods as fodder for live stock should be avoided.

  13. Effect of CuF2 on the Synthesis and Superconducting Properties of (Bi,Pb)2Sr2Ca2Cu3O10 Bulk Ceramic Samples

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Andersen, Niels Hessel

    2013-01-01

    Bulk polycrystalline samples with Bi1.72Pb0.34Sr1.87Ca1.91Cu3.13O9.83−x F x (0.00≤x≤0.51) were prepared by a solid-state route using CuF2 as a fluorine source. CuF2 was introduced in the precursor powders either by direct mixing with the other starting reagents or by addition to precalcined precu...

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

    Science.gov (United States)

    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

  15. Geopolymers for immobilization of Cr(6+), Cd(2+), and Pb(2+).

    Science.gov (United States)

    Zhang, Jianguo; Provis, John L; Feng, Dingwu; van Deventer, Jannie S J

    2008-09-15

    Alkali activation of fly ash by sodium silicate solutions, forming geopolymeric binders, provides a potential means of treating wastes containing heavy metals. Here, the effects on geopolymer structure of contamination of geopolymers by Cr(VI), Cd(II) and Pb(II) in the forms of various nitrate and chromate salts are investigated. The addition of soluble salts results in a high extent of dispersal of contaminant ions throughout the geopolymer matrix, however very little change in geopolymer structure is observed when these materials are compared to their uncontaminated counterparts. Successful immobilization of these species will rely on chemical binding either into the geopolymer gel or into other low-solubility (silicate or aluminosilicate) phases. In the case of Pb, the results of this work tentatively support a previous identification of Pb(3)SiO(5) as a potential candidate phase for hosting Pb(II) within the geopolymer structure, although the data are not entirely conclusive. The addition of relatively low levels of heavy metal salts is seen to have little effect on the compressive strength of the geopolymeric material, and in some cases actually gives an increase in strength. Sparingly soluble salts may undergo some chemical conversion due to the highly alkaline conditions prevalent during geopolymerization, and in general are trapped in the geopolymer matrix by a simple physical encapsulation mechanism. Lead is in general very effectively immobilized in geopolymers, as is cadmium in all except the most acidic leaching environments. Hexavalent chromium is problematic, whether added as a highly soluble salt or in sparingly soluble form.

  16. K-edge EXAFS and XANES studies of Cu in CdTe thin-film solar cells

    Science.gov (United States)

    Liu, Xiangxin; Gupta, Akhlesh; Compaan, Alvin D.; Leyarovska, Nadia; Terry, Jeff

    2002-03-01

    Copper has been identified as a very important dopant element in CdTe thin-film solar cells. Cu is a deep acceptor in CdTe and is commonly used to obtain a heavily doped, low resistance back contact to polycrystalline CdTe. Cu also helps to increase the open circuit voltage of the cell. However, Cu is also a fast diffuser in CdTe, especially along grain boundaries, and can accumulate at the CdS/CdTe junction. It is suspected of leading to cell performance degradation in some cases. The present study is designed to help identify the lattice location of the Cu in CdTe. Cu K-edge, x-ray absorption (XAS) measurements were conducted on Cu in thin films of CdTe. Experiments were performed at the MR-CAT beamline at the Advanced Photon Source. The 3 mm CdTe layers were magnetron sputtered onto fused silica substrates. Some films were diffused with Cu from a 200 Å layer of evaporated Cu. XAS spectra were collected in fluorescence geometry with a 13 elements Ge detector. Quantitative fluorescence spectroscopy measurements were also performed. Details of the Cu environment and possible changes with time will be reported.

  17. Nano-structured CuO-Cu2O Complex Thin Film for Application in CH3NH3PbI3 Perovskite Solar Cells

    Science.gov (United States)

    Chen, Lung-Chieh; Chen, Cheng-Chiang; Liang, Kai-Chieh; Chang, Sheng Hsiung; Tseng, Zhong-Liang; Yeh, Shih-Chieh; Chen, Chin-Ti; Wu, Wen-Ti; Wu, Chun-Guey

    2016-09-01

    Nano-structured CuO-Cu2O complex thin film-based perovskite solar cells were fabricated on an indium tin oxide (ITO)-coated glass and studied. Copper (Cu) thin films with a purity of 99.995 % were deposited on an ITO-coated glass by magnetron reactive sputtering. To optimize the properties of the nano-structured CuO-Cu2O complex thin films, the deposited Cu thin films were thermally oxidized at various temperatures from 300 to 400 °C. A CH3NH3PbI3 perovskite absorber was fabricated on top of CuO-Cu2O complex thin film by a one-step spin-coating process with a toluene washing treatment. Following optimization, the maximum power conversion efficiency (PCE) exceeded 8.1 %. Therefore, the low-cost, solution-processed, stable nano-structured CuO-Cu2O complex thin film can be used as an alternative hole transport layer (HTL) in industrially produced perovskite solar cells.

  18. Relation Between pH and Desorption of Cu, Cr, Zn, and Pb from Industrially Polluted Soils

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Hansen, Henrik K.; Jensen, Pernille Erland

    2009-01-01

    Desorption of Cu, Cr, Pb, and Zn from industrially polluted soils as a result of acidification is in focus. The eight soils of the investigation vary greatly in composition and heavy metal concentration/combination. Three soils had elevated concentrations of Cu, Pb, and Zn; regardless of pollution...... level, pollution origin, and soil type, the order for desorption as pH decreased was Zn > Cu > Pb. Turning to a single heavy metal in different soils, there was a huge difference in the pH at which the major desorption started. The variation was most significant for Pb where, e.g., less than 10......% was desorbed at pH 2.5 from one soil, whereas in another soil 60% Pb was desorbed at this pH. Sequential extraction was made and the soils in which a high percentage of Pb was found in the residual phase (adsorbed strongest) was also the soils where less Pb was desorbed at low pH in the desorption experiments...

  19. Enhanced removal of Cd(II) and Pb(II) by composites of mesoporous carbon stabilized alumina

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Weichun [Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Lushan South Road 932, Changsha 410017 (China); Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Lushan South Road 932, Changsha 410017 (China); Tang, Qiongzhi; Wei, Jingmiao; Ran, Yajun [Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Lushan South Road 932, Changsha 410017 (China); Chai, Liyuan [Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Lushan South Road 932, Changsha 410017 (China); Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Lushan South Road 932, Changsha 410017 (China); Wang, Haiying, E-mail: haiyw25@163.com [Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Lushan South Road 932, Changsha 410017 (China); Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Lushan South Road 932, Changsha 410017 (China)

    2016-04-30

    Graphical abstract: - Highlights: • Mesoporous carbon stabilized alumina was prepared by one-pot hard-templating method. • MC/Al{sub 2}O{sub 3} showed excellent performance for Cd(II) and Pb(II) adsorption. • Enhanced adsorption was due to the high surface area and special functional groups. - Abstract: A novel adsorbent of mesoporous carbon stabilized alumina (MC/Al{sub 2}O{sub 3}) was synthesized through one-pot hard-templating method. The adsorption potential of MC/Al{sub 2}O{sub 3} for Cd(II) and Pb(II) from aqueous solution was investigated compared with the mesoporous carbon. The results indicated the MC/Al{sub 2}O{sub 3} showed excellent performance for Cd(II) and Pb(II) removal, the adsorption capacity reached 49.98 mg g{sup −1} for Cd(II) with initial concentration of 50 mg L{sup −1} and reached 235.57 mg g{sup −1} for Pb(II) with initial concentration of 250 mg L{sup −1}, respectively. The kinetics data of Cd(II) adsorption demonstrated that the Cd(II) adsorption rate was fast, and the removal efficiencies with initial concentration of 10 and 50 mg L{sup −1} can reach up 99% within 5 and 20 min, respectively. The pseudo-second-order kinetic model could describe the kinetics of Cd(II) adsorption well, indicating the chemical reaction was the rate-controlling step. The mechanism for Cd(II) and Pb(II) adsorption by MC/Al{sub 2}O{sub 3} was investigated by X-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared spectroscopy (FTIR), and the results indicated that the excellent performance for Cd(II) and Pb(II) adsorption of MC/Al{sub 2}O{sub 3} was mainly attributed to its high surface area and the special functional groups of hydroxy-aluminum, hydroxyl, carboxylic through the formation of strong surface complexation or ion-exchange. It was concluded that MC/Al{sub 2}O{sub 3} can be recognized as an effective adsorbent for removal of Cd(II) and Pb(II) in aqueous solution.

  20. Spatial and temporal variations in inhalable CuZnPb aerosols within the Mexico City pollution plume.

    Science.gov (United States)

    Moreno, T; Querol, X; Pey, J; Minguillón, M C; Pérez, N; Alastuey, A; Bernabé, R M; Blanco, S; Cárdenas, B; Eichinger, W; Salcido, A; Gibbons, W

    2008-03-01

    We report on the CuPbZn content of PM10 and PM2.5 samples collected from three sites (urban T0, suburban T1 and rural T2) during the Mexico City MILAGRO campaign of March 2006. Daytime city centre concentrations of summation operator CuZnPb(PM10) were much higher (T0 > 450 ng m(-3)) than at the suburban site (T1 inversion layer, but decreased at the rural site. Transient spikes in concentrations of different metals, e.g. a "copper event" at T0 (CuPM10 281 ng m(-3)) and "zinc event" at T1 (ZnPM10 1481 ng m(-3)) on the night of March 7-8, demonstrate how industrial pollution sources produce localised chemical inhomogeneities in the city atmosphere. Most metal aerosols are <2.5 microm and SEM study demonstrates the dominance of Fe, Ti, Ba, Cu, Pb and Zn (and lesser Sn, Mo, Sb, W, Ni, V, As, Bi) in metalliferous particles that have shapes including spherical condensates, efflorescent CuZnClS particles, cindery Zn, and Cu wire. Metal aerosol concentrations do not change in concert with PM10 mass, which is more influenced by wind resuspension than industrial emissions. Metalliferous particles can induce cell damage, and PM composition is probably more important than PM mass, with respect to negative health effects, so that better monitoring and control of industrial emissions would likely produce significant improvements in air quality.

  1. Spin-coating deposition of PbS and CdS thin films for solar cell application

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Jayesh; Mighri, Frej [Laval University, CREPEC, Department of Chemical Engineering, Quebec, QC (Canada); Ajji, Abdellah [Ecole Polytechnique, CREPEC, Chemical Engineering Department, Montreal, QC (Canada); Tiwari, Devendra; Chaudhuri, Tapas K. [Charotar University of Science and Technology (CHARUSAT), Dr. K.C. Patel Research and Development Centre, Anand District, Gujarat (India)

    2014-12-15

    In this work, we describe a simple spin-coating deposition technique for lead sulphide (PbS) and cadmium sulphide (CdS) films from a methanolic metal-thiourea complex. The characterization of the films by X-ray diffraction and X-ray photoelectron spectroscopy techniques revealed that pure cubic phase PbS and CdS layers were formed via this method. As shown by atomic force microscopy and scanning electron microscopy results, both films were homogeneous and presented a smooth surface. Optical properties showed that the energy band gap of PbS and CdS films were around 1.65 and 2.5 eV, respectively. The PbS film is p-type in nature with an electrical conductivity of around 0.8 S/cm. The hole concentration and mobility were 2.35 x 10{sup 18} cm{sup -3} and 2.16 x 10{sup -3} cm{sup 2}/V/s, respectively, as determined from Hall measurement. Both films were used to develop a thin film solar cell device of graphite/PbS/CdS/ITO/glass. Device characterization showed the power conversion efficiency of around 0.24 %. The corresponding open circuit voltage, short circuit current and fill factor were 0.570 V, 1.32 mA/cm{sup 2} and 0.32, respectively. (orig.)

  2. Superior Photocurrent of Quantum Dot Sensitized Solar Cells Based on PbS : In/CdS Quantum Dots

    Directory of Open Access Journals (Sweden)

    Zongbo Huang

    2015-01-01

    Full Text Available PbS : In and CdS quantum dots (QDs are sequentially assembled onto a nanocrystalline TiO2 film to prepare a PbS : In/CdS cosensitized photoelectrode for QD sensitized solar cells (QDSCs. The results show that PbS : In/CdS QDs have exhibited a significant effect in the light harvest and performance of the QDSC. In the cascade structure of the electrode, the reorganization of energy levels between PbS and TiO2 forms a stepwise structure of band-edge levels which is advantageous to the electron injection into TiO2. Energy conversion efficiency of 2.3% is achieved with the doped electrode, under the illumination of one sun (AM1.5, 100 mW cm2. Besides, a remarkable short circuit current density (up to 23 mA·cm−2 is achieved in the resulting PbS : In/CdS quantum dot sensitized solar cell, and the related mechanism is discussed.

  3. Quantum chemistry insight into Mg-substitution in chlorophyll by toxic heavy metals: Cd, Hg and Pb

    Science.gov (United States)

    Bechaieb, Rim; Ben Akacha, Azaiez; Gérard, Hélène

    2016-10-01

    In this paper, we examined the structural, electronic and energetic data associated to the Mg-substitution in chlorophyll by three major toxic pollutants: Cd2+, Hg2+ and Pb2+. We evidenced a highly versatile bonding of the cations with the pheophytin ligand, with a strong out-of-plane distortion for Hg and Pb. The binding energies ranged from slightly stronger than Mg2+ in the case of Hg2+ to much smaller for Pb2+. Nevertheless, our various approaches of free cations solvation allowed us to evidence that Mg-substitution should be possible for all title elements.

  4. Role of polycrystallinity in CdTe and CuInSe sub 2 photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Sites, J.R. (Colorado State Univ., Fort Collins, CO (United States))

    1991-01-01

    The polycrystalline nature of thin-film CdTe and CuInSe{sub 2} solar cells continues to be a major factor in several individual losses that limit overall cell efficiency. This report describes progress in the quantitative separation of these losses, including both measurement and analysis procedures. It also applies these techniques to several individual cells to help document the overall progress with CdTe and CuInSe{sub 2} cells. Notably, CdTe cells from Photon Energy have reduced window photocurrent losses to 1 mA/Cm{sup 2}; those from the University of South Florida have achieved a maximum power voltage of 693 mV; and CuInSe{sub 2} cells from International Solar Electric Technology have shown a hole density as high as 7 {times} 10{sup 16} cm{sup {minus}3}, implying a significant reduction in compensation. 9 refs.

  5. Cd(II and Pb(II complexes of the polyether ionophorous antibiotic salinomycin

    Directory of Open Access Journals (Sweden)

    Tanabe Makoto

    2011-09-01

    Full Text Available Abstract Background The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II ions in in vivo experiments, despite so far no Pb(II-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as possible antidotes in the agriculture, a detailed study on their in vitro complexation with toxic metal ions is required. In the present paper we report for the first time the preparation and the structure elucidation of salinomycin complexes with ions of cadmium(II and lead(II. Results New metal(II complexes of the polyether ionophorous antibiotic salinomycin with Cd(II and Pb(II ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa undergoes a reaction with heavy metal(II ions to form [Cd(Sal2(H2O2] (1 and [Pb(Sal(NO3] (2, respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield 1. Two salinomycin anions occupy the equatorial plane of the Cd(II center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II cation. Complex 2 consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation. Conclusion The formation of the salinomycin heavy metal(II complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock

  6. 基于GSH-CdTe/CdS量子点的荧光变化研究hsDNA与盐酸洛美沙星-Cu(Ⅱ)配合物的相互作用%Interaction of Herring Sperm DNA with Lomefloxacin Hydrochloride-Cu(Ⅱ) Based on Changes in the Fluorescence Intensity of GSH-CdTe/CdS Quantum Dots

    Institute of Scientific and Technical Information of China (English)

    沈益忠; 刘绍璞; 殷鹏飞; 何佑秋

    2013-01-01

    Glutathione (GSH)-capped CdTe/CdS quantum dots(GSH-CdTe/CdS QDs) were synthesized in aqueous solution.The particle sizes and morphological characteristics of GSH-CdTe/CdS QDs were investigated by transmission electron microscopy(TEM).The results exhibits that the particle size of as-prepared QDs has a narrow size distribution and good dispersivity.In Tris-HCl buffer medium (pH =7.6),lomefloxacin hydrochloride-Cu (Ⅱ) coordination compound(LMFH-Cu2+) was adsorbed to the surfaces of GSH-CdTe/CdS QDs through electrostatic attraction and formed ground state complex,which resulted in the quenching of the fluorescence of GSH-CdTe/CdS QDs.Adding herring sperm DNA (hsDNA) to GSH-CdTe/CdS QDs-LMFH-Cu(Ⅱ) system led to the fluorescence intensity of GSH-CdTe/CdS QDs recover,which can be explained by that the addition of hsDNA to the system induced LMFH-Cu(Ⅱ) to dissociate from the surface of GSH-CdTe/CdS QDs and embed into its double helix structure.According to the fluorescence quenching and restoration for GSH-CdTe/CdS QDs,fluorescence reversible control of GSH-CdTe/CdS QDs was realized.Compared with the interaction between GSH-CdTe/CdS QDs and LMFH,the interaction of GSH-CdTe/CdS QDs-LMFH-Cu (Ⅱ)-hsDNA was studied by fluorescence (FL),resonance Rayleigh scattering(RRS) and ultraviolet-visible absorption (UV-Vis) spectra.Meanwhile,the interaction mechanism was discussed and corresponding model of interaction was built.%采用水相法合成了谷胱甘肽(GSH)修饰的CdTe/CdS量子点(GSH-CdTe/CdS QDs).透射电子显微镜表征结果表明,GSH-CdTe/CdS QDs的粒径分布均匀,分散性好.在Tris-HCl(pH=7.6)缓冲液中,由于静电引力作用,带正电的盐酸洛美沙星(LMFH)-Cu(Ⅱ)配合物[LMFH-Cu(Ⅱ)]吸附到带负电的GSH-CdTe/CdSQDs表面形成基态复合物,导致GSH-CdTe/CdS QDs的荧光猝灭.随后,向GSH-CdTe/CdS QDs-LMFH-Ca(Ⅱ)配合物体系中加入鲱鱼精DNA(hsDNA),hsDNA可诱导LMFH-Cu(Ⅱ)配合物从GSH-CdTe/CdS QDs表面脱落而嵌

  7. Structure and age of the Cerro de Pasco Cu-Zn-Pb-Ag deposit, Peru

    Science.gov (United States)

    Cheney, E. S.

    1991-04-01

    The world-famous Cu-Zn-Pb-Ag deposit at Cerro de Pasco, Peru, consists of texturally massive pyrite, texturally massive sphalerite-galena-pyrite, and veins containing pyrite and enargite. Historically the deposit has been considered to be the hydrothermal product of the adjacent Miocene volcanic and intrusive complex (locally known as the “Vent”). However, both the texturally massive sulfides of the deposit and the pre-Miocene strata are cut by the Longitudinal fault, one of the largest faults in the district, but the Vent is not. Imbrication by the Longitudinal fault zone (duplex structures) has thickened the deposit so that it is amenable to open-pit mining. Dikes and pyrite-enargite veins pass from the Vent into the massive sulfides; fragments of massive pyrite occur in the Vent. Thus, no matter what their origin, the texturally massive sulfides are older and, therefore, genetically unrelated to the Vent.

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

    Science.gov (United States)

    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.

  9. Interaction Kinetics between Sn-Pb Solder Droplet and Au/Ni/Cu Pad

    Institute of Scientific and Technical Information of China (English)

    Fuquan LI; Chunqing WANG; Yanhong TIAN

    2006-01-01

    The interfacial phenomena of the Sn-Pb solder droplet on Au/Ni/Cu pad are investigated. A continuous AuSn2and needle-like AuSn4 are formed at the interface after the liquid state reaction (soldering). The interfacial reaction between the solder and Au layer continues during solid state aging with AuSn4 breaking off from the interface and felling into the solder. The kinetics of Au layer dissolution and diffusion into the solder during soldering and aging is analyzed to elucidate intermetallic formation mechanism at the solder/Au pad interface.The concentration of Au near the solder/pad interface is identified to increase and reach the solubility limit during the period of liquid state reaction. During solid state reaction, the thickening of Au-Sn compound is mainly controlled by element diffusion.

  10. Stopping Power of Al, Cu, Ag, Au, Pb, and U for 5-18-MeV Protons and Deuterons

    DEFF Research Database (Denmark)

    Sørensen, H.; Andersen, Hans Henrik

    1973-01-01

    High energy protons and deuterons of energies between 9 and 18 MeV have been used to extend earlier measurements of the stopping power of Al, Cu, Ag and Au and the stopping powers of Pb and U in the range 5-18 MeV have been determined for the first time. Mean excitation potentials have been...

  11. Retention and distribution of Cu, Pb, Cr, and Zn in a full-scale hybrid constructed wetland receiving municipal sewage

    NARCIS (Netherlands)

    Xiao, H.W.; Zhang, S.L.; Zhai, J.; He, Q.; Mels, A.R.; Ning, K.J.; Liu, J.

    2013-01-01

    This study was conducted to investigate the retention and distribution of Cu, Pb, Cr, and Zn in a hybrid constructed wetland (CW) that consists of both vertical baffled flow wetlands (VBFWs) and horizontal subsurface flow wetlands (HSSFs) with unique flow regimes and oxygen distribution. The heavy m

  12. Geology, mineralogy and fluid inclusion data from the Arapucan Pb Zn Cu Ag deposit, Canakkale, Turkey

    Science.gov (United States)

    Orgün, Yüksel; Gültekin, Ali Haydar; Onal, Ayten

    2005-07-01

    The Arapucan Pb-Zn-Cu-Ag deposit occurs as hydrothermal veins in diabase and altered Triassic metasandstones adjacent to calc-alkaline intrusive igneous rocks. The deposit is an important commercial source of base metal in northwestern Turkey. Potential by-products are silver and gold. The geology of the area includes a Paleozoic metamorphic basement, Triassic sedimentary rocks with carbonate blocks, Tertiary granitoids and Neogene volcanics. The mineral assemblage includes galena, quartz, calcite, sphalerite, chalcopyrite and pyrite as well as minor bismuthinite, tetrahedrite, pyrolusite, hematite, scheelite, malachite, magnetite, limonite and rutile. Silver is associated with tetrahedrite. Early hydrothermal activity was responsible for the formation of three hypogene alteration types of decreasing intensity: silicification, sericitization and argillic alteration. These alteration styles show a rough spatial zonation. The ore stage clearly postdates hydrothermal alteration, as indicated by the occurrence of ore minerals in vuggy cavities and fractures in silica bodies. The deposit contains evidence of at least two periods of hypogene mineralization separated by a period of faulting. In addition to Pb, Zn, Cu, Ag and Au, the ores contain substantial quantities of W, Bi, Sb and Te. Average δ 34S values for galena and pyrite are -3.95 and -2.24‰, respectively, suggesting an igneous source for both the sulphur and metals. However, geological and geochemical interpretations suggest that at least some of the metals were leached from the metasandstones and diabases. Fluid inclusions in main-stage sphalerite homogenize at 229-384 °C with salinities ranging from 1.7 to 18.5 eq.wt% NaCl. The deposits formed as the result of the interaction of two aqueous fluids: a higher-salinity fluid (probably magmatic) and a dilute meteoric fluid. The narrow range of δ 34S (galena and pyrite) values (-5.2 to -1.2‰ CDT) suggests that the sulphur source of the hydrothermal fluids

  13. Biosorption behaviors of Cu2+,Zn2+, Cd2+ and mixture by waste activated sludge

    Institute of Scientific and Technical Information of China (English)

    LUO Sheng-lian; YUAN Lin; CHAI Li-yuan; MIN Xiao-bo; WANG Yun-yan; FANG Yan; WANG Pu

    2006-01-01

    Biosorption of heavy metal ions, such as Cu2+, Cd2+ and Zn2+, was carried out using waste activated sludge from municipal sewage treatment plant as adsorption material, and the effects of parameters, such as pH value, temperature, reaction time and sorption duration, were studied in detail. The results indicate that the removal rates of Cu2+, Zn2+ and Cd2+ with low concentration are 96.47%, 80% and 90%, respectively, adsorbed by waste activated sludge. Little effect of dosage of activated sludge on the adsorption of Cu2+ and more effects on the adsorption of Zn2+ and Cd2+ are observed. Little effect oftemperature is observed, while pH value and adsorption time exert important influence on the sorption process. The adsorption behaviors of heavy metal ions all have parabolic relationships with pH value. The optimum pH value is between 6 and 10, and the optimum adsorption time is 1 h. In single heavy metal ion system, the sorption processes of Cu2+, Zn2+ and Cd2+ are in accordance with Freundlich model, which indicates that it is suitable for the treatment of these three heavy metal ions using intermittent operation. In addition, the sorption capacity of the sludge for Cu2+ is preferential to the other two ions.

  14. Nucleation and evolution of dynamic damage at Cu/Pb interfaces using molecular dynamics

    Science.gov (United States)

    Fensin, S. J.; Valone, S. M.; Cerreta, E. K.; Gray, G. T.; Shao, S.

    2017-01-01

    For ductile metals, the process of dynamic fracture occurs through nucleation, growth and coalescence of voids. For high purity single-phase metals, it has been observed by numerous investigators that voids tend to heterogeneously nucleate at grain boundaries and all grain boundaries are not equally susceptible to void nucleation. However, for materials of engineering significance, especially those with second phase particles, it is less clear if the type of bi-metal interface between the two phases will affect void nucleation and growth. To approach this problem in a systematic manner two bi-metal interfaces between Cu and Pb have been investigated: {111} and {100}. Qualitative and quantitative analysis of the collected data from molecular dynamics shock and spall simulations suggests that Pb becomes disordered during shock compression and is the preferred location for void nucleation under tension. Despite the interfaces being aligned with the spall plane (by design), they are not the preferred location for void nucleation irrespective of interface type.

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

    Energy Technology Data Exchange (ETDEWEB)

    Arfaoui, Lobna; Kouass, Salah [Laboratoire des matériaux utiles, Institut National de Recherche et d' Analyse Physico-Chimique (INRAP) Sidi Thabet, 2020 Tunis (Tunisia); Dhaouadi, Hassouna, E-mail: dhaouadihassouna@yahoo.fr [Laboratoire Matériaux Traitement et Analyse, Institut National de Recherche et d' Analyse Physico-Chimique (INRAP) Sidi Thabet, 2020 Tunis (Tunisia); Jebali, Raouf [Laboratoire des matériaux utiles, Institut National de Recherche et d' Analyse Physico-Chimique (INRAP) Sidi Thabet, 2020 Tunis (Tunisia); Touati, Fathi [Laboratoire Matériaux Traitement et Analyse, Institut National de Recherche et d' Analyse Physico-Chimique (INRAP) Sidi Thabet, 2020 Tunis (Tunisia)

    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.

  16. Heavy metal accumulations of 24 asparagus bean cultivars grown in soil contaminated with Cd alone and with multiple metals (Cd, Pb, and Zn).

    Science.gov (United States)

    Zhu, Yun; Yu, Hui; Wang, Junli; Fang, Wei; Yuan, Jiangang; Yang, Zhongyi

    2007-02-01

    Crops grown in heavy metal contaminated soils are an important avenue for these toxic pollutants entering the human food chain. Information on how crops respond to soil contaminations of single versus multiple metals is scarce and much needed. This study investigated the accumulation of Cd by 24 cultivars of asparagus bean (Vigna unguiculata subsp. Sesquipedalis L., family Fabaceae) under a low level (0.8 mg kg-1) and a high level (11.8 mg kg-1) of Cd exposure in a garden experiment, and that in a field experiment with Cd, Pb, and Zn (1.2, 486, and 1114 mg kg-1, respectively) contaminated soil. Both experiments showed that there were highly significant variations among the tested cultivars in Cd accumulation by roots, stems, leaves, and fruits of asparagus bean. In the garden experiment, all cultivars under the low Cd exposure and 41.7% of the tested cultivars under the high Cd exposure bore fruits (pods) whose Cd concentrations were lower than 0.05 mg kg-1 fw and therefore were safe for consumption. In addition, the fruit Cd concentrations of cultivars with black seed coats were significantly lower than those with red or spotted seed coats. These results suggest that asparagus bean is a hypo-accumulator to Cd pollutant and the trait of Cd accumulation is genetic-dependent among cultivars. In the field experiment, correlation between fruit Cd and Pb concentrations was significantly positive (p pollution-safe-cultivars (PSC) in multi-metal polluted condition could refer to the PSCs selected under a high level exposure of a single heavy metal.

  17. Phytoavailability of Cd and Pb in crop straw biochar-amended soil is related to the heavy metal content of both biochar and soil.

    Science.gov (United States)

    Shen, Xin; Huang, Dao-You; Ren, Xue-Fei; Zhu, Han-Hua; Wang, Shuai; Xu, Chao; He, Yan-Bing; Luo, Zun-Chang; Zhu, Qi-Hong

    2016-03-01

    Crop straw biochar incorporation may be a sustainable method of amending soil, but feedstock-related Cd and Pb content is a major concern. We investigated the effects of heavy metal-rich (RC) and -free biochar (FC) on the phytoavailability of Cd and Pb in two acidic metalliferous soils. Biochar significantly increased soil pH and improved plant growth. Pb in soil and plant tissues significantly decreased after biochar application, and a similar pattern was observed for Cd after FC application. RC significantly increased NH4NO3-extractable Cd in both lightly contaminated (YBS) and heavily contaminated soils (RS). The Cd content of plants grown on YBS increased, whereas it decreased on RS. The Cd and Pb input-output balance suggested that RC application to YBS might induce a soil Cd accumulation risk. Therefore, identifying heavy metal contamination in biochar is crucial before it is used as a soil amendment.

  18. Chelation Study of Captopril with Cd2+ and Pb2+

    Directory of Open Access Journals (Sweden)

    Mohammad Joshaghani

    2008-01-01

    Full Text Available The protonation constants of Captopril, (1-(3-mercapto-2-(S-methyl-1-oxopropyl-S(L proline, (CPL and stabilities of its two divalent metal ions Cd(II and Pb(II were determined potentiometrically in two different metal to ligand ratio 1:1 and 1:2 systems and in water and methanol-water binary mixtures using the computer Best program. Two protonation constants were obtained which were assigned to the carboxylic and thiol groups. All protonation and stability constants increased with decreasing the dielectric constant on going from the pure water to the binary mixtures. An excellent similarity in stabilities of studied metal ions strongly suggests that both metal ions are coordinated by CPL in a same manner through the thiol group.

  19. Physical properties of nanostructured (PbSx(CuS1−x composite thin films grown by successive ionic layer adsorption and reaction method

    Directory of Open Access Journals (Sweden)

    A.U. Ubale

    2016-03-01

    Full Text Available Nanostructured ternary semiconducting (PbSx(CuS1−x thin films were grown on glass substrates by successive ionic layer adsorption and reaction (SILAR technique at room temperature. The structural, morphological and optical characterizations of the films were carried out by X-ray diffraction, scanning electron microscopy and UV–Vis spectrophotometer respectively. The structural studies revealed that, (PbSx(CuS1−x films are nanocrystalline in nature and have mixed phase of cubic PbS and hexagonal CuS. The optical absorption measurements showed that band gap energy of (PbSx(CuS1−x can be engineered between 2.57 and 2.28 eV by varying compositional parameter ‘x’. The room temperature dc dark electrical resistivity of PbS film is found to be 28.85 Ωcm and it decreases when content of Cu in composite increases and becomes 0.05 Ωcm for pure CuS. The thermo-emf measurements showed that the as deposited (PbSx(CuS1−x films are of n-type. The water angle contact measurements of (PbSx(CuS1−x, revealed that, films are hydrophilic in nature and it could be advantageous in electrochemical application.

  20. Design of Three-shell Icosahedral Matryoshka Clusters A@B12@A20 (A = Sn, Pb; B = Mg, Zn, Cd, Mn)

    Science.gov (United States)

    Huang, Xiaoming; Zhao, Jijun; Su, Yan; Chen, Zhongfang; King, R. Bruce

    2014-11-01

    We propose a series of icosahedral matryoshka clusters of A@B12@A20 (A = Sn, Pb; B = Mg, Zn, Cd), which possess large HOMO-LUMO gaps (1.29 to 1.54 eV) and low formation energies (0.06 to 0.21 eV/atom). A global minimum search using a genetic algorithm and density functional theory calculations confirms that such onion-like three-shell structures are the ground states for these A21B12 binary clusters. All of these icosahedral matryoshka clusters, including two previously found ones, i.e., [As@Ni12@As20]3- and [Sn@Cu12@Sn20]12-, follow the 108-electron rule, which originates from the high Ih symmetry and consequently the splitting of superatom orbitals of high angular momentum. More interestingly, two magnetic matryoshka clusters, i.e., Sn@Mn12@Sn20 and Pb@Mn12@Pb20, are designed, which combine a large magnetic moment of 28 µB, a moderate HOMO-LUMO gap, and weak inter-cluster interaction energy, making them ideal building blocks in novel magnetic materials and devices.

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

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    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 undercool- ings. 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.

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

    Institute of Scientific and Technical Information of China (English)

    ZHANG XueHua; RUAN Ying; WANG WeiLi; WEI BingBo

    2007-01-01

    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.

  3. 市售谷物中 PbCd 含量测定与风险评估%Determination of Pb and Cd contents in commercial cereals and their risk analysis

    Institute of Scientific and Technical Information of China (English)

    刘辉; 刘恩岐; 巫永华; 张建萍; 陈尚龙

    2014-01-01

    The Pb and Cd contents in 12 kinds of cereal samples were determined by microwave digestion-graphite furnace atomic absorption spectrometry,respectively.The pollution situations of the samples were assessed according to the national safety standards about the pollutant in cereal.The dietary expo-sure risk of Pb and Cd in cereal was assessed according to the maximum allowable intake of heavy metal pollutants (RfD value)recommended by USEPA (2000).The results showed that the exposure risk coef-ficient of Pb and Cd was less than 1 with the dietary patterns of eating single rice or two kinds of grain collocation.But all samples were slightly contaminated by Pb;maize,oat and wheat flour were slightly contaminated by Cd;while rice,pea,broad bean were around the warning line of Cd pollution.It is nec-essary to reinforce supervision of heavy metal pollution in agricultural products market.%采用微波消解—石墨炉原子吸收光谱法测定市售12种谷物(豆类)中的 Pb、Cd 含量,按照我国粮食污染物限量安全标准分析其污染水平,依据美国环境保护局推荐的重金属污染物最大允许摄入量(RfD 值)评估谷物中 Pb、Cd 污染的膳食暴露风险。结果显示,以单一大米及大米、小麦粉和其他谷物搭配的两种谷物膳食模式的 Pb、Cd 污染暴露风险指数均<1,不存在健康安全暴露风险;但12种谷物样品均存在轻度 Pb 污染风险,玉米、燕麦、小麦粉等样品存在轻度 Cd 污染风险,大米、豌豆和蚕豆等样品处于 Cd 污染警戒线,应加强对农产品销售市场重金属污染安全风险的监测。

  4. Real-time observation of nanoscale topological transitions in epitaxial PbTe/CdTe heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Groiss, H., E-mail: heiko.groiss@jku.at, E-mail: istvan.daruka@jku.at; Daruka, I., E-mail: heiko.groiss@jku.at, E-mail: istvan.daruka@jku.at; Springholz, G.; Schäffler, F. [Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Linz 4040 (Austria); Koike, K.; Yano, M. [Nanomaterials Microdevices Research Center, Osaka Institute of Technology, Asahi-ku Ohmiya, Osaka 535-8585 (Japan); Hesser, G. [Center for Surface- and Nanoanalytics (ZONA), Johannes Kepler University, Linz 4040 (Austria); Zakharov, N.; Werner, P. [Max Planck Institute of Microstructure Physics, Halle 06120 (Germany)

    2014-01-01

    The almost completely immiscible PbTe/CdTe heterostructure has recently become a prototype system for self-organized quantum dot formation based on solid-state phase separation. Here, we study by real-time transmission electron microscopy the topological transformations of two-dimensional PbTe-epilayers into, first, a quasi-one-dimensional percolation network and subsequently into zero-dimensional quantum dots. Finally, the dot size distribution coarsens by Ostwald ripening. The whole transformation sequence occurs during all stages in the fully coherent solid state by bulk diffusion. A model based on the numerical solution of the Cahn-Hilliard equation reproduces all relevant morphological and dynamic aspects of the experiments, demonstrating that this standard continuum approach applies to coherent solids down to nanometer dimensions. As the Cahn-Hilliard equation does not depend on atomistic details, the observed morphological transformations are general features of the model. To confirm the topological nature of the observed shape transitions, we developed a parameter-free geometric model. This, together with the Cahn-Hilliard approach, is in qualitative agreement with the experiments.

  5. Real-time observation of nanoscale topological transitions in epitaxial PbTe/CdTe heterostructures

    Directory of Open Access Journals (Sweden)

    H. Groiss

    2014-01-01

    Full Text Available The almost completely immiscible PbTe/CdTe heterostructure has recently become a prototype system for self-organized quantum dot formation based on solid-state phase separation. Here, we study by real-time transmission electron microscopy the topological transformations of two-dimensional PbTe-epilayers into, first, a quasi-one-dimensional percolation network and subsequently into zero-dimensional quantum dots. Finally, the dot size distribution coarsens by Ostwald ripening. The whole transformation sequence occurs during all stages in the fully coherent solid state by bulk diffusion. A model based on the numerical solution of the Cahn-Hilliard equation reproduces all relevant morphological and dynamic aspects of the experiments, demonstrating that this standard continuum approach applies to coherent solids down to nanometer dimensions. As the Cahn-Hilliard equation does not depend on atomistic details, the observed morphological transformations are general features of the model. To confirm the topological nature of the observed shape transitions, we developed a parameter-free geometric model. This, together with the Cahn-Hilliard approach, is in qualitative agreement with the experiments.

  6. Efficiency of Chitosan for the Removal of Pb (II, Fe (II and Cu (II Ions from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Soheil Sobhanardakani

    2014-09-01

    Full Text Available Background: Heavy metals have been recognized as harmful environmental pollutant known to produce highly toxic effects on different organs and systems of both humans and animals. The aim of this paper is to evaluate the adsorption potential of chitosan for the removal of Pb(II, Fe(II and Cu(II ions from aqueous solutions. Methods: This study was conducted in laboratory scale. In this paper chitosan has been used as an adsorbent for the removal of Pb(II, Fe(II and Cu(II from aqueous solution. In batch tests, the effects of parameters like pH solution (1.0-8.0, initial metal concentrations (100-1000 mgL-1, contact time (5.0-150 min and adsorbent dose (1.0-7.0 g on the adsorption process were studied. Results: The results showed that the adsorption of Pb(II, Fe(II and Cu(II ions on chitosan strongly depends on pH. The experimental isothermal data were analyzed using the Langmuir and Freundlich equations and it was found that the removal process followed the Langmuir isotherm and maximum adsorption capacity for the adsorption of Pb(II, Fe(II and Cu(II ions by the chitosan were 55.5mg g−1, 71.4 mg g−1 and 59 mg g−1, respectively, under equilibrium conditions at 25±1 ºC. The adsorption process was found to be well described by the pseudo-second-order rate model. Conclusion: The obtained results showed that chitosan is a readily, available, economic adsorbent and was found suitable for removing Pb(II, Fe(II and Cu(II ions from aqueous solution.

  7. Properties of complexes of galactomannan of Leucaena leucocephala and Al3+, Cu2+ and Pb2+.

    Science.gov (United States)

    Lombardi, Simone Cristina; Mercê, Ana Lucia Ramalho

    2003-08-01

    The use of biopolymers in many industrial processes is on the increase. The different interactions of biopolymers and electrolytes either in aqueous solutions or in solid state provide different physico-chemical properties and a simple correlation cannot be established. In this study, in order to determine the properties of the complexes of galactomannan of Leucaena leucocephala (gal) with the metal ions Al3+ and Pb2+, toxic elements and Cu2+, essential, the logs of the binding constants of the complexes formed in the aqueous solutions were calculated. Their rheological properties, their thermal behavior, the infrared characteristics and shape and form of the films formed by those complexes in solid state were also determined. The aqueous solutions properties have shown a better complexation between gal and Al3+. The species distribution diagrams have shown an existence of complex species going from acidic to basic pH values. Infrared spectra have proved the complexations as well as the viscosity studies. Thermal stabilities in general were smaller in the complexed species than in the native biopolymers and the films obtained from aqueous solutions showed for Cu2+ the most different morphology compared to the biopolymer itself. A use can be suggested of this biopolymer in environmental remediations besides its already established industrial uses.

  8. Research progress of CdSe/ZnS and PbSe-quantum-dot doped fibers and fiber amplifiers%CdSe/ZnS和PbSe量子点光纤及光纤放大器研究进展

    Institute of Scientific and Technical Information of China (English)

    程成; 江慧绿

    2011-01-01

    Quantum dots(QDs), quantum dot doped fibers(QDFs) and quantum dot doped fiber amplifiers (QDFAs) are ones of the research focuses in recent years. In this study, the spectral characteristics and absorption-emission cross section of the CdSe/ZnS and PbSe QDs were described. The results showed that QDs had enhanced absorption and emission. The research advances were summarized for the CdSe/ ZnS QD doped fibers with different QD concentrations, and for the PbSe QDF materials fabricated by fusion and sol-gel method. The advantages and disadvantages of the methods in preparing QDF materials were analyzed. In addition, the researches on the PbSe QDFA were reviewed. A suggestion was given for potential applications of the QDFs in the future.%近年来,纳米晶体(量子点)以及量子点光纤、量子点光纤放大器成为一个研究热点.介绍了CdSe/ZnS和PbSe量子点的光谱特性以及量子点的吸收-辐射截面,表明量子点具有强的吸收和发射.总结了低浓度和较高浓度CdSe/ZnS量子点掺杂光纤、熔融法及溶胶凝胶法制备PbSe量子点光纤材料的最新研究进展,分析了两种方法制备量子点光纤材料的优缺点,概述了PbSe量子点光纤放大器的研究近况,展望了量子点光纤的应用前景.

  9. TiO{sub 2} flower-like nanostructures decorated with CdS/PbS nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Trenczek-Zajac, Anita, E-mail: anita.trenczek-zajac@agh.edu.pl [AGH University of Science and Technology, Faculty of Materials Science and Ceramics, al. A. Mickiewicza 30, 30-059 Krakow (Poland); Kusior, Anna; Lacz, Agnieszka; Radecka, Marta [AGH University of Science and Technology, Faculty of Materials Science and Ceramics, al. A. Mickiewicza 30, 30-059 Krakow (Poland); Zakrzewska, Katarzyna [AGH University of Science and Technology, Faculty of Computer Science, Electronics and Telecommunications, al. A. Mickiewicza 30, 30-059 Krakow (Poland)

    2014-12-15

    Highlights: • TiO{sub 2} flower-like nanostructures were prepared with the use of Ti foil and 30% H{sub 2}O{sub 2}. • QDs of CdS and PbS were deposited using the SILAR method. • The SILAR method makes it possible to control the size of QDs. • Band gap energy of CdS was found to be 2.35 eV. • Sensitization of TiO{sub 2} with CdS or PbS improves the photoelectrochemical properties. - Abstract: Flower-like nanostructures of TiO{sub 2} were prepared by immersing Ti foil in 30% H{sub 2}O{sub 2} at 80 °C for times varying from 15 to 240 min. Upon annealing at 450 °C in an Ar atmosphere, the received amorphous samples crystallized in an anatase structure with rutile as a minority phase. SEM images revealed that partially formed flowers were present at the surface of the prepared samples as early as after 15 min of immersion. The size of the individual flowers increased from 400–800 nm after 15 min of reaction to 2.5–6.0 μm after 240 min. It was also found that surface is very rough and surface development is considerable. After 45 min of immersion, the nanoflowers were sensitized with CdS and PbS quantum dots (QDs-CdS/QDs-PbS) deposited using the SILAR method from water- and methanol-based precursor solutions at different concentrations (0.001–0.1 M). QDs-CdS crystallized in the hawleyite structure, while QDs-PbS in the galena form. SEM analysis showed the tendency of quantum dots to agglomerate at high concentrations of the precursor in water-based solutions. QDs obtained from methanol-based solutions were uniformly distributed. The produced QDs-PbS were smaller than QDs-CdS. Based on the optical reflectance spectra, the band-gap energies of TiO{sub 2} nanostructures with and without QDs were calculated to be 3.32 eV for flower-like TiO{sub 2} nanostructures and 2.35 eV for QDs-CdS. The photoelectrochemical behaviour of nanoflowers was found to improve significantly after the deposition of QDs-CdS.

  10. Effects of Different Doping Ratio of Cu Doped CdS on QDSCs Performance

    Directory of Open Access Journals (Sweden)

    Xiaojun Zhu

    2015-01-01

    Full Text Available We use the successive ionic layer adsorption and reaction (SILAR method for the preparation of quantum dot sensitized solar cells, to improve the performance of solar cells by doping quantum dots. We tested the UV-Vis absorption spectrum of undoped CdS QDSCs and Cu doped CdS QDSCs with different doping ratios. The doping ratios of copper were 1 : 100, 1 : 500, and 1 : 1000, respectively. The experimental results show that, under the same SILAR cycle number, Cu doped CdS quantum dot sensitized solar cells have higher open circuit voltage, short circuit current density photoelectric conversion efficiency than undoped CdS quantum dots sensitized solar cells. Refinement of Cu doping ratio are 1 : 10, 1 : 100, 1 : 200, 1 : 500, and 1 : 1000. When the proportion of Cu and CdS is 1 : 10, all the parameters of the QDSCs reach the minimum value, and, with the decrease of the proportion, the short circuit current density, open circuit voltage, and the photoelectric conversion efficiency are all increased. When proportion is 1 : 500, all parameters reach the maximum values. While with further reduction of the doping ratio of Cu, the parameters of QDSCs have a decline tendency. The results showed that, in a certain range, the lower the doping ratio of Cu, the better the performance of quantum dot sensitized solar cell.

  11. CdS nanowires decorated with Cu{sub 2}O nanospheres: Synthesis, formation process and enhanced photoactivity and stability

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang; Dong, Hailiang; Jia, Husheng; Xu, Bingshe; Yu, Chunyan; Zhang, Zhuxia, E-mail: zhangzhuxia@tyut.edu.cn

    2015-09-25

    Highlights: • Novel CdS/Cu{sub 2}O heterostructural composites were synthesized by a two-step chemical method. • A formation process of CdS/Cu{sub 2}O heterostructural composites. • The CdS/Cu{sub 2}O heterostructural composites were found to have superior photocatalytic performance and stability. - Abstract: CdS/Cu{sub 2}O heterostructural materials were successfully synthesized by a solvent-thermal process followed by a chemical bath deposition process. Structures and morphologies of the obtained CdS/Cu{sub 2}O composites were characterized by XRD, SEM, and TEM; the experimental results indicate that the surface of CdS nanowires (NWs) is decorated with spherical Cu{sub 2}O whose diameter ranges from 100 to 200 nm. Through crystal shape-evolution, the formation process of these hierarchical nanostructures was rationally proposed. Briefly, in the chemical bath deposition process, Cu(OH){sub 2} colloids generate firstly, and then the colloids transform into nanobelts after adding ascorbic acid (AA). With the reaction time further increasing, nanobelts aggregate together to form the hierarchical nanospheres on the surface of CdS NWs. The photoactivity of CdS/Cu{sub 2}O composite for methyl orange (MO) photodegradation was investigated in detail. The obtained high photocatalytic efficiency can be attributed to the heterojunction structure, which results in the efficient separation of photo-generated electrons and holes.

  12. 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.

    Science.gov (United States)

    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.

  13. Photoluminescence study of CdTe/CdS solar cells grown from a source with Cu residual impurity

    Science.gov (United States)

    Ghimpu, L.; Ursaki, V. V.; Potlog, T.; Tiginyanu, I. M.

    2005-11-01

    Three photoluminescence (PL) bands centred at 1.30, 1.35 and 1.45 eV have been observed in the PL spectrum of CdTe/CdS thin film solar cells grown by close space sublimation (CSS) techniques from a source with Cu residual impurity. The bands at 1.30 and 1.45 eV were found to be independent of the technological conditions of the CSS process, while the intensity of the band at 1.35 eV proved to increase with the increase of the source temperature and the decrease of the substrate temperature. This PL band is suggested to correspond to donor-CuCd defects related to the incorporation in the CdTe film of the impurity from the source. The other two bands are associated with defects whose formation does not depend upon the technological processes applied, the band at 1.45 eV being attributed to a VCd-ClTe defect.

  14. Removal of Pb(II) and Cd(II) ions from aqueous solution by thiosemicarbazide modified chitosan.

    Science.gov (United States)

    Li, Manlin; Zhang, Zengqiang; Li, Ronghua; Wang, Jim J; Ali, Amjad

    2016-05-01

    The removal of Pb(II) and Cd(II) ions from aqueous solution by thiosemicarbazide modified chitosan (TCS) was studied in this article. The synthesized TCS was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), element analysis, N2 adsorption-desorption, scanning electron microscopy (SEM) and X-ray photoelectron spectrophotometer (XPS). Moreover, the influence of solution pH, contact time, initial heavy metal concentration, and solution temperature on the adsorption process was examined, and the adsorbent reusability and adsorption mechanisms were also studied. The results showed that TCS adsorbed greater amount of Pb(II) and Cd(II) ions than the raw chitosan. The adsorption amounts of Pb(II) and Cd(II) ions were affected by increasing solution pH and temperature. The maximum adsorption capacities of the TCS for Pb(II) and Cd(II) ions were found to be 325.2 and 257.2 mg/g, respectively. The endothermic adsorption fitted the pseudo-second-order kinetics equation and the adsorption isotherms could be well described by Langmuir model. The metal ions adsorption mechanism was concluded to be mainly dominated by complexation reaction process. The desorption study indicated that the target adsorbent was easy to be regenerated.

  15. The YBCO-PbS high-temperature superconducting system. Further investigations. [YBaCuO-PbS

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, A.K. (Dept. of Applied Physics, GND Univ., Amritsar (India)); Sharma, T.P. (Institute of Advanced Studies, Meerut (India). Dept. of Physics); Shahi, K. (Advanced Centre for Materials Science, IIT, Kanpur (India))

    1993-12-16

    Further investigations on the recently reported YBCO-PbS HTS system are reported. The system is found to have conducting BaPbO[sub 3] as a second phase, which fills the intergrain vacant spaces forming a composite-like microstructure. Thermoanalytical investigations revealed that PbS addition enhances the synthesis of the Y-123-phase and lowers the temperature of partial melting of this phase, which is essential to further reduce the voids. The metallurgical reaction occurring during sintering is also determined and investigated. It is shown that these composite superconducting materials have better normal-state, superconducting, and mechanical properties. (orig.)

  16. Ectomycorrhizal Fungus-Induced Changes of Cu and Cd speciation in the rhizosphere of Chinese Pine Seedlings

    Institute of Scientific and Technical Information of China (English)

    HUANG Yi; LI Ting; HUANG Zhi-Ji; FEI Ying-Heng

    2008-01-01

    To understand the role of ectomycorrhizas in improving the tolerance of its host to excessive heavy metals in soil, this study was conducted to exam the patterns of four fractions (the exchangeable, the carbonate-bound, the Fe-Mn oxide-bound and the organically bound) of both Cu and Cd in the rhizosphere of Chinese pine (Pinus tabulaeformis) seedlings grown in excessive Cu and Cd environment. The results showed that the speciation of Cu and Cd in the rhizosphere was significantly influenced by inoculation of ectomycorrhizal fungus Boletus edulis. Compared to the rhizosphere, the content of exchangeable Cu slightly decreased in the mycorrhizosphere of the seedlings grown in 166 and 400 mg kg-1Cu contaminated soil, whereas the exchangeable Cd in the mycorrhizosphere decreased remarkably to only 33% and to 60% that of the rhizosphcre at 0.75 and 1.50 mg kg-1 Cd levels, respectively. These indicate the potential capacity of mycorrhizas to alleviate the damage of heavy metals to the host plants by reducing the bioavailability of heavy metals in soil. Distribution of the 4 tested fractions of Cu and Cd at different contamination levels showed that there was a strong tendency of changing from loosely associatcd fractions to strongly associated fractions in the mycorrhizosphere. The most stable Cd fraction, organically bound Cd, was significantly larger in the mycorrhizosphere than in the rhizosphere at different Cd contamination levels. This phenomenon was also observed for Cu but the difference was not statistically significant.

  17. Elevated CO2 increases glomalin-related soil protein (GRSP) in the rhizosphere of Robinia pseudoacacia L. seedlings in Pb- and Cd-contaminated soils.

    Science.gov (United States)

    Jia, Xia; Zhao, Yonghua; Liu, Tuo; Huang, Shuping; Chang, Yafei

    2016-11-01

    Glomalin-related soil protein (GRSP), which contains glycoproteins produced by arbuscular mycorrhizal fungi (AMF), as well as non-mycorrhizal-related heat-stable proteins, lipids, and humic materials, is generally categorized into two fractions: easily extractable GRSP (EE-GRSP) and total GRSP (T-GRSP). GRSP plays an important role in soil carbon (C) sequestration and can stabilize heavy metals such as lead (Pb), cadmium (Cd), and manganese (Mn). Soil contamination by heavy metals is occurring in conjunction with rising atmospheric CO2 in natural ecosystems due to human activities. However, the response of GRSP to elevated CO2 combined with heavy metal contamination has not been widely reported. Here, we investigated the response of GRSP to elevated CO2 in the rhizosphere of Robinia pseudoacacia L. seedlings in Pb- and Cd-contaminated soils. Elevated CO2 (700 μmol mol(-1)) significantly increased T- and EE- GRSP concentrations in soils contaminated with Cd, Pb or Cd + Pb. GRSP contributed more carbon to the rhizosphere soil organic carbon pool under elevated CO2 + heavy metals than under ambient CO2. The amount of Cd and Pb bound to GRSP was significantly higher under elevated (compared to ambient) CO2; and elevated CO2 increased the ratio of GRSP-bound Cd and Pb to total Cd and Pb. However, available Cd and Pb in rhizosphere soil under increased elevated CO2 compared to ambient CO2. The combination of both metals and elevated CO2 led to a significant increase in available Pb in rhizosphere soil compared to the Pb treatment alone. In conclusion, increased GRSP produced under elevated CO2 could contribute to sequestration of soil pollutants by adsorption of Cd and Pb.

  18. Interlaboratory comparison exercise for the determination of As, Cd, Ni and Pb in PM 10 in Europe

    Science.gov (United States)

    Gerboles, M.; Buzica, D.; Brown, R. J. C.; Yardley, R. E.; Hanus-Illnar, A.; Salfinger, M.; Vallant, B.; Adriaenssens, E.; Claeys, N.; Roekens, E.; Sega, K.; Jurasović, J.; Rychlik, S.; Rabinak, E.; Tanet, G.; Passarella, R.; Pedroni, V.; Karlsson, V.; Alleman, L.; Pfeffer, U.; Gladtke, D.; Olschewski, A.; O'Leary, B.; O'Dwyer, M.; Pockeviciute, D.; Biel-Ćwikowska, J.; Turšič, J.

    2011-07-01

    This paper presents the results of an intercomparison exercise for the determination of arsenic (As), cadmium (Cd), nickel (Ni) and lead (Pb) in PM 10, which are regulated by the European Directives for ambient air quality. Thirteen laboratories participated, generally using the European reference methods of measurement which consist of a microwave digestion followed by analysis with either ICP-MS or GFAAS. Each participant was asked to analyse five test samples: a liquid Certified Reference Material (CRM), two sub-samples of a NIST dust CRM (one already-digested and one to be digested by the participants) and two loaded filters (one already-digested and one to be digested by the participants). Participants were able to meet the Data Quality Objectives (DQOs) of the European Directives (expanded uncertainties of 25% for Pb and 40% for As, Cd and Ni) for 93% of all test samples, except for the loaded filter that were digested by the participants. In fact, only 76% of DQOs were met for this test sample, the closest to a routine sample analysis in the laboratory. The difficulties in analysing this test sample came mainly from digestion and contamination processes. Satisfactory results were also obtained using other digestion techniques (Soxhlet extraction and high pressure methods) and analytical methods (ICP-OES for Cd, Ni and Pb, EDXRF for Pb and Ni and Voltammetry for As, Ni, and Pb). Participants claimed uncertainties of about 10% for Pb and between 15 and 20% for As, Cd and Ni. These uncertainties were confirmed for 77% of results. The reproducibility of the methods of measurement was between 41 and 54% while repeatability remained between 5 and 12% except for the analysis of As on filters which was up to 20%. The majority of participant results showed higher between-day variability (14 ± 11%) than within-day variability (6.0 ± 5.3%).

  19. Characterization of pbt genes conferring increased Pb2+ and Cd2+ tolerance upon Achromobacter xylosoxidans A8.

    Science.gov (United States)

    Hložková, Kateřina; Suman, Jáchym; Strnad, Hynek; Ruml, Tomas; Paces, Vaclav; Kotrba, Pavel

    2013-12-01

    The cluster of pbtTFYRABC genes is carried by plasmid pA81. Its elimination from Achromobacter xylosoxidans A8 resulted in increased sensitivity towards Pb(2+) and Cd(2+). Predicted pbtTRABC products share strong similarities with Pb(2+) uptake transporter PbrT, transcriptional regulator PbrR, metal efflux P1-ATPases PbrA and CadA, undecaprenyl pyrophosphatase PbrB and its signal peptidase PbrC from Cupriavidus metallidurans CH34. Expression of pbtABC or pbtA in a metal-sensitive Escherichia coli GG48 rendered the strain Pb(2+)-, Cd(2+)- and Zn(2+)-tolerant and caused decreased accumulation of the metal ions. Accumulation of Pb(2+), but not of Cd(2+) or Zn(2+), was promoted in E. coli expressing pbtT. Additional genes of the pbt cluster are pbtF and pbtY, which encode the cation diffusion facilitator (CDF)-like transporter and a putative fatty acid hydroxylase of unknown function, respectively. Expression of pbtF did not confer increased metal tolerance upon E. coli GG48, although the protein showed measurable Pb(2+)-efflux activity. Unlike the pbtT promoter, promoters of pbtABC, pbtF and pbtY contain features characteristic of promoters controlled by metal-responsive transcriptional regulators of the MerR family. Upregulation of pbtABC, pbtF and pbtY upon Pb(2+), Cd(2+) and Zn(2+) exposure was confirmed in wild-type Achromobacter xylosoxidans A8. Gel shift assays proved binding of purified PbtR to the respective promoters.

  20. Assessment of Ni, Cu, Zn and Pb levels in beach and dune sands from Havana resorts, Cuba.

    Science.gov (United States)

    Díaz Rizo, Oscar; Buzón González, Fran; Arado López, Juana O

    2015-11-15

    Concentrations of nickel (Ni), copper (Cu), zinc (Zn) and lead (Pb) in beach and dune sands from thirteen Havana (Cuba) resorts were estimated by X-ray fluorescence analysis. Determined mean metal contents (in mg·kg(-1)) in beach sand samples were 28±12 for Ni, 35±12 for Cu, 31±11 for Zn and 6.0±1.8 for Pb, while for dune sands were 30±15, 38±22, 37±15 and 6.8±2.9, respectively. Metal-to-iron normalization shows moderately severe and severe enrichment by Cu. The comparison with sediment quality guidelines shows that dune sands from various resorts must be considered as heavily polluted by Cu and Ni. Almost in every resort, the Ni and Cu contents exceed their corresponding TEL values and, in some resorts, the Ni PEL value. The comparison with a Havana topsoil study indicates the possible Ni and Cu natural origin.

  1. Room temperature synthesis and spectral characterization of Cu2+-doped CdO powder

    Science.gov (United States)

    Venkata Reddy, Ch.; Shim, J.; Byon, C.; Krishna Rao, L. V.; Satish, D. V.; Ravikumar, R. V. S. S. N.

    2016-03-01

    In the present study, we have synthesized undoped and Cu2+-doped CdO nanopowders by a mild solution method at room temperature. Powder X-ray diffraction, optical absorption, electron paramagnetic resonance and Fourier transform infrared measurements are used to characterize prepared powders. The powder X-ray diffraction patterns reflect the cubic crystal structure for undoped and Cu2+-doped CdO powders. Surface morphology images and compositional features are studied by scanning electron microscopy and energy-dispersive X-ray techniques, respectively. The optical absorption spectra exhibit a single absorption band for Cu2+-doped sample, which is the characteristic absorption band of distorted octahedral site symmetry. By correlating the electron paramagnetic resonance and optical results for Cu2+-doped CdO nanopowder, bonding parameters are evaluated. These values indicate the partial covalency of in-plane σ ( α 2) and in-plane π bonding ( β12 ) between copper ions and their ligands. The FT-IR spectra indicate the fundamental vibrations of Cd-O.

  2. PENENTUAN KANDUNGAN LOGAM Cd DAN Cu DALAM PRODUK IKAN KEMASAN KALENG SECARA SPEKTROFOTOMETRI SERAPAN ATOM (SSA

    Directory of Open Access Journals (Sweden)

    Hellna Tehubijuluw

    2013-05-01

    Full Text Available Determination of cadmium and copper concentration of canned fish have been done. Some canned fished were taken away from three mercks circulating in a market and marked as RS (the 1st sample, NF(2nd sample, and CP(3rd sample. The aim of this research is to determine of  cadmium (Cd and copper (Cu content of canned fish and to compare the content with the standard limit regulated by the Directorate General of Drug and Food Control No: 03725/B/SK/VII/89. Determination of metal concentration was conducted using  atomic absorption spectrophotometer (AAS. It was found that Cd concentrations of RS and  NF samples are 0.1969 mg/kg and0.0448 mg/kg, respecively while for  CP it was not detected. For Cu concentrations of  RS, NF, and CP are 3.3303 mg/kg, 4.6130 mg/kg, 3.3047 mg/kg  respectively. The results indicated that the samples of the canned fishes  have been contaminated with Cd and Cu metals although the levels of those metals are still lower than  the maximum limit regulated by the Directorate General of Drug and Food Control No: 03725/B/SK/VII/89 where the maximum limit for Cd and  Cu are 0,2 mg.kg and 5.0 mg/kg respectively.    

  3. CuO nanostructures grown by the SILAR method: Influence of Pb-doping on the morphological, structural and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Bayansal, F., E-mail: fbayansal@gmail.com [Department of Metallurgical and Materials Engineering, Faculty of Technology, Mustafa Kemal University, Hatay (Turkey); Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, Hatay (Turkey); Gülen, Y. [Department of Physics, Faculty of Arts and Sciences, Marmara University, İstanbul (Turkey); Şahin, B. [Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, Hatay (Turkey); Kahraman, S. [Department of Metallurgical and Materials Engineering, Faculty of Technology, Mustafa Kemal University, Hatay (Turkey); Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, Hatay (Turkey); Çetinkara, H.A. [Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, Hatay (Turkey)

    2015-01-15

    Highlights: • CuO nanostructures with Pb-doping by the SILAR method is reported for the first time. • CuO nanostructures of different morphologies were grown by different Pb ratios. • E{sub g} values of the films can be altered by changing Pb doping concentrations. - Abstract: CuO nanostructures with and without Pb were synthesized by the Successive Ionic Layer Adsorption and Reaction method. The films were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and ultraviolet–visible spectrophotometry. Scanning electron microscopy results showed that the morphology of the film surface was changed from plate-like to coral-like nanostructures with increasing Pb concentration. The X-ray diffraction patterns showed the monoclinic crystal structure with preferential planes of (1{sup ¯}11) and (1 1 1). Furthermore, ultraviolet–visible spectra showed that the band gap of the films was tailored by Pb doping.

  4. Adsorptive removal of Cd(II) and Pb(II) ions from aqueous solutions by using Turkish illitic clay.

    Science.gov (United States)

    Ozdes, Duygu; Duran, Celal; Senturk, Hasan Basri

    2011-12-01

    The ability of Turkish illitic clay (TIC) in removal of Cd(II) and Pb(II) ions from aqueous solutions has been examined in a batch adsorption process with respect to several experimental conditions including initial solution pH, contact time, initial metal ions concentration, temperature, ionic strength, and TIC concentration, etc. The characterization of TIC was performed by using FTIR, XRD and XRF techniques. The maximum uptake of Cd(II) (11.25 mg g(-1)) and Pb(II) (238.98 mg g(-1)) was observed when used 1.0 g L(-1) of TIC suspension, 50 mg L(-1) of initial Cd(II) and 250 mg L(-1) of initial Pb(II) concentration at initial pH 4.0 and contact time of 240 min at room temperature. The experimental data were analyzed by the Langmuir, Freundlich, Temkin and Dubinin Radushkevich (D-R) isotherm models. The monolayer adsorption capacity of TIC was found to be 13.09 mg g(-1) and 53.76 mg g(-1) for Cd(II) and Pb(II) ions, respectively. The kinetics of the adsorption was tested using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models. The results showed that the adsorption of Cd(II) and Pb(II) ions onto TIC proceeds according to the pseudo-second-order model. Thermodynamic parameters including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes indicated that the present adsorption process was feasible, spontaneous and endothermic in the temperature range of 5-40 °C.

  5. Distribution of As, Cd, Pb, and Zn in redox features of mine-waste impacted wetland soils

    Energy Technology Data Exchange (ETDEWEB)

    Strawn, Daniel G.; Hickey, Patrick J.; McDaniel, Paul A.; Baker, Leslie L. [Idaho Univ., Moscow (United States). Soil and Land Resources Div.

    2012-08-15

    Purpose: Wetland soils of the Coeur d'Alene (CdA) River Basin of northern Idaho, USA are contaminated with toxic elements released during mining activities. In this paper, we report results from a multi-scale investigation of total As, Cd, Pb, and Zn distributions along a transect of these contaminated soils. Materials and methods: Four sites along an 80-m transect were established at the Black Rock Slough wetland in CdA River Basin. The elevation difference between the upslope and lowland site was 1.1 m. Soils were sampled from three depths, down to 45 cm. Redoximorphic features were isolated from the soils and categorized into five types of cemented particles, and Fe-enriched and depleted soil masses. Soils and isolated soil separates were analyzed for total elemental concentration. Results and discussion: Within soil profiles, contaminants are enriched in surface horizons as compared to the original depositional profiles. Enrichment was more dramatic in the upland sites than the lowland sites. Fe-enriched masses that ranged in size from a few millimeters to several centimeters were also enriched in As, Pb, and Zn. At the smallest scale investigated, five different soil aggregate types ranging in size from 1 to 2 mm in diameter had distinct contaminant associations: Fe-cemented aggregates were elevated in As and Zn; Mn-cemented aggregates had more than five times as much Pb as the bulk soil; root channels were elevated in As; and charcoal particles were elevated in all contaminants, particularly Pb and Cd. Conclusions: Results show that in wetland soils pedogenic processes differentially distribute contaminants amongst the redoximorphic features. The distribution is affected by landscape position and water table influence. At the pedon scale, there is an enrichment of As, Cd, Pb, and Zn in surface horizons, suggesting that upward flux of contaminants is occurring. This contaminant redistribution should be considered in design of management and remediation

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

    Science.gov (United States)

    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.

  7. Cd, Ni, Cr and Pb distribution in biosolid pellets used as soil amendment

    Science.gov (United States)

    Jordán, Manuel M.; Rincón-Mora, Beatriz; Belén Almendro-Candel, María; Navarro Pedreño, Jose; Gómez Lucas, Ignacio; Bech, Jaume; Roca, Nuria; Pardo, Francisco

    2016-04-01

    The application of biosolids to a soil is a method that offers important benefits (Navarro et al. 2003). The transport and application costs are quite low (mostly if they are dehydrated biosolids or pellets) if soils are located near a wastewater treatment plant. It is possible to recycle nutrients (N, P, and K) and organic matter by improving the physical and chemical characteristics of the soil and by reducing the fertilizer costs. However, the use of biosolids may also has several problems, such as the presence of quantities of metals that could be toxic for plants or could contaminate ground-waters after being leached. Heavy metals are one of the most serious environmental pollutants because of its high toxicity, abundance and easy accumulation by plant (Soriano-Disla et al. 2014; Rosen and Chen 2014). Contamination of soils by potentially toxic elements (e.g. Cd, Ni, Cr, Pb) from amendments of biosolids is subject to rigorous controls within the European Union. The present study was designed to examine the partition of selected heavy metals in biosolid pellets, and also to relate the distribution patterns of these metals. Samples were collected from the treatment of urban wastewater at the drying grounds of a wastewater processing plant. The samples correspond to biosolids with humidities below 20% and are representative of the three horizons within the pile: the isolation surface (H1), the mesophilous area (H2), and the thermophilous area (H3). Biosolid aggregates were placed in a pellet press and then compacted. Total content of metals was determined following microwave digestion and analysed by ICP/MS. Triplicate samples were weighed in polycarbonate centrifuge tubes and sequentially extracted. The distribution of chemical forms of Cd, Ni, Cr, and Pb in the biosolids was studied using a sequential extraction procedure that fractionates the metal into soluble-exchangeable, specifically sorbed-carbonate bound, oxidizable, reducible, and residual forms. The

  8. Surface photovoltage analyses of Cu(In,Ga)S2/CdS and Cu(In,Ga)S2/In2S3 photovoltaic junctions

    Science.gov (United States)

    Merdes, S.; Osterloh, F.; Sáez-Araoz, R.; Klaer, J.; Klenk, R.; Dittrich, T.

    2013-05-01

    Spectrally dependent surface photovoltage measurements were performed with repetitive regime on Cu(In,Ga)S2 absorbers and on Cu(In,Ga)S2/CdS and Cu(In,Ga)S2/In2S3 junctions. The results are correlated to current-voltage investigations of the respective completed solar cells. The measurements show the presence of a space charge region in the bare Cu(In,Ga)S2 absorbers due to a high density of surface states. It is found that deposition of CdS increases the band bending whereas deposition of In2S3 does not change it.

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

    Science.gov (United States)

    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.

  10. Point Defects in Pb-, Bi-, and In-Doped CdZnTe Detectors: Deep-Level Transient Spectroscopy (DLTS) Measurements

    Science.gov (United States)

    Gul, R.; Keeter, K.; Rodriguez, R.; Bolotnikov, A. E.; Hossain, A.; Camarda, G. S.; Kim, K. H.; Yang, G.; Cui, Y.; Carcelen, V.; Franc, J.; Li, Z.; James, R. B.

    2012-03-01

    We studied, by current deep-level transient spectroscopy (I-DLTS), point defects induced in CdZnTe detectors by three dopants: Pb, Bi, and In. Pb-doped CdZnTe detectors have a new acceptor trap at around 0.48 eV. The absence of a VCd trap suggests that all Cd vacancies are compensated by Pb interstitials after they form a deep-acceptor complex [[PbCd]+-V{Cd/2-}]-. Bi-doped CdZnTe detectors had two distinct traps: a shallow trap at around 36 meV and a deep donor trap at around 0.82 eV. In detectors doped with In, we noted three well-known traps: two acceptor levels at around 0.18 eV (A-centers) and 0.31 eV (VCd), and a deep trap at around 1.1 eV.

  11. Temporal changes in Hg, Pb, Cd and Zn environmental concentrations in the southern Baltic Sea sediments dated with 210Pb method

    Directory of Open Access Journals (Sweden)

    Tamara Zalewska

    2015-01-01

    Full Text Available The article presents data on heavy metal – Hg, Pb, Cd and Zn – distribution in the layers of marine sediments from the off-shore areas of the southern Baltic Sea: Gdańsk Deep, SE Gotland Basin and Bornholm Deep. Depth profiles of metal concentrations were converted to time-based profiles using the 210Pb dating method and verified by 137Cs distribution in the vertical profile. The linear sedimentation rates in the Gdańsk Deep and SE Gotland Basin are similar, 0.18 cm yr−1 and 0.14 cm yr−1, respectively, while the region of the Bornholm Deep is characterized by a greater sedimentation rate: 0.31 cm yr−1. Regarding anthropogenic pressure, Gdańsk Deep receives the largest share among the analyzed regions. The maximal metal concentrations detected in this area were Zn – 230 mg kg−1, Pb – 77 mg kg−1, Cd – 2.04 mg kg−1 and Hg – 0.27 mg kg−1. The least impact of anthropogenic pressure was noticeable in SE Gotland Basin. The combination of sediment dating with the analysis of vertical distribution of heavy metals in sediments benefited in the determination of target metal concentrations used in environmental status assessments. Reference values of heavy metal concentrations in marine sediments were determined as: Zn – 110 mg kg−1, Pb – 30 mg kg−1, Cd – 0.3 mg kg−1 and Hg – 0.05 mg kg−1 from the period of minor anthropogenic pressure. Basing on the determined indices: enrichment factor (EF, geoaccumulation indicator (Igeo and contamination factor (CF the status of marine environment was assessed regarding the pollution with heavy metals.

  12. Characterization of cadmium biosorption by Exiguobacterium sp. isolated from farmland soil near Cu-Pb-Zn mine.

    Science.gov (United States)

    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.

  13. The formation of different phases of Cu {sub x}Te and their effects on CdTe/CdS solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, J. [National Renewable Energy Laboratory (NREL), Golden, CO 80401 (United States)]. E-mail: Jie_Zhou@nrel.gov; Wu, X. [National Renewable Energy Laboratory (NREL), Golden, CO 80401 (United States); Duda, A. [National Renewable Energy Laboratory (NREL), Golden, CO 80401 (United States); Teeter, G. [National Renewable Energy Laboratory (NREL), Golden, CO 80401 (United States); Demtsu, S.H. [Department of Physics, Colorado State University, Fort Collins, CO 80523 (United States)

    2007-06-25

    Material studies and device applications of Cu {sub x}Te in an NREL-developed CdTe solar cell structured as glass/Cd{sub 2}SnO{sub 4}/ZnSnO {sub x}/CdS/CdTe are presented. The Cu {sub x}Te primary back contact was formed by evaporating a Cu layer with various thicknesses at room temperature on HNO{sub 3}/H{sub 3}PO{sub 4} (NP) solution etched CdTe layer. A post-annealing was then followed. The structural evolution and electrical properties of Cu {sub x}Te were investigated. Cu/Te ratio and post-annealing temperature are two processing parameters in this study. The Cu {sub x}Te phases are mainly controlled by the Cu/Te ratio. After a post-annealing at a low temperature, such as 100 deg. C, no Cu {sub x}Te phase transformation from its as-deposited phase was observed. A post-annealing treatment at a higher temperature, such as 250 deg. C, can reveal the stoichiometric Cu {sub x}Te phases based on the Cu/Te ratio used in the devices. But a post-annealing at a further higher temperature, such as 400 deg. C, resulted in a complicated Cu {sub x}Te phase appearance. CuTe, Cu{sub 1.4}Te, and Cu{sub 2}Te are three major phases detected by X-ray diffraction (XRD) for different Cu thickness application annealed at 250 deg. C. Application of Cu thicker than 60 nm degrades open-circuit voltage (V {sub oc}) and shunting resistance (R {sub sh}), but increases series resistance (R {sub s}). The correlation between device performance and the Cu {sub x}Te back contact illustrates that the process used for forming the Cu{sub 2}Te back contact failed to produce good fill factor (FF) and also introduced higher barrier height. The best device was observed for a back contact with a mixed Cu{sub 1.4}Te and CuTe phases.

  14. Chemical reactions at CdS heterojunctions with CuInSe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Aquino, Angel; Rockett, Angus [Department of Materials Science and Engineering, University of Illinois, 1304 West Green Street, Urbana, Illinois 61801 (United States)

    2013-03-15

    The stability of the CdS/CuInSe{sub 2} (CIS) heterojunction is critical to understanding the projected lifetime of CIS devices and the effect of processing conditions on the nanoscale chemistry of the heterojunction. This article reports the results of annealing heterojunctions between CdS deposited by chemical bath deposition and single crystal and polycrystalline CIS films between 200 and 500 Degree-Sign C for 10 to 150 min. No atomic movement was observed by secondary ion mass spectrometry at temperatures of 300 Degree-Sign C and below. At 400 Degree-Sign C even for the shortest time studied, Cu and In were found throughout the region initially consisting of CdS only and Cd was found to have moved into the CIS. In the polycrystal, annealing at 500 Degree-Sign C resulted in movement of Cd throughout the CIS layer. No time dependence was observed in the 400 and 500 Degree-Sign C anneals indicating that a reaction had occurred forming a compound that was in thermodynamic equilibrium with the remaining CIS. Diffusion turns on rapidly between 300 and 400 Degree-Sign C, indicating a high activation energy for atomic movement ({approx}2.4 eV). The onset of diffusion is consistent with the onset of Cu diffusion in CIS.

  15. Synchrotron-radiation photoemission study of CdS/CuInSe sub 2 heterojunction formation

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, A.J.; Gebhard, S. (Solar Energy Research Institute, 1617 Cole Boulevard, Golden, CO (USA)); Rockett, A. (Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL (USA)); Colavita, E. (Department of Physics, University of Calabria, I-87036 Arcavacata di Rende, Cosenza (Italy)); Engelhardt, M.; Hoechst, H. (Synchrotron Radiation Center, University of Wisconsin-Madison, Stoughton, WI (USA))

    1990-10-15

    Synchrotron-radiation soft-x-ray photoemission spectroscopy was used to investigate the development of the electronic structure at the CdS/CuInSe{sub 2} heterojunction interface. CdS overlayers were deposited in steps on single-crystal {ital p}- and {ital n}-type CuInSe{sub 2} at 250 {degree}C. Results indicate that the CdS grows in registry with the substrate, initially in a two-dimensional growth mode followed by three-dimensional island growth as is corroborated by reflection high-energy electron-diffraction analysis. Photoemission measurements were acquired after each growth in order to observe changes in the valence-band electronic structure as well as changes in the In 4{ital d}, Se 3{ital d}, Cd 4{ital d}, and S 2{ital p} core lines. The results were used to correlate the interface chemistry with the electronic structure at these interfaces and to directly determine the CdS/CuInSe{sub 2} heterojunction valence-band discontinuity and the consequent heterojunction band diagram. These results show that the Katnani-Margaritondo method is unreliable in determining offsets for heterojunctions where significant Fermi-level pinning may occur and where the local structure and chemistry of the interface depends strongly on the specific heterojunction.

  16. Preparation, processing and tunneling in YBa2Cu3O(7-[delta])-Pb native-barrier structures

    Energy Technology Data Exchange (ETDEWEB)

    Frangi, F.; Dwir, B.; James, J. H.; Gauzzi, A.; Pavuna, D. (Swiss Federal Institute of Technology, Lausanne (Switzerland). Institute of Micro- and Optoelectonics)

    1993-06-15

    In this study, a procedure for the preparation of small (40[times]40[mu]m[sup 2]) window-type YBa2Cu3O(7-[delta])-Pb junctions with YSZ (yttrium-stabilized zirconium-oxide) insulator and native tunnel barrier has been developed. This paper presents the patterning technique of the two electrodes based on photolithography and wet etching. From the device characteristics, the nature of the barrier was found to be semiconducting. The tunneling I-V curves showed a behavior dominated by the Pb gap at 1.3 meV below 7.2 K. The dI/dV curve also showed an additional feature at 5.3 meV, which disappeared above Tc of Pb, and was attributed to longitudinal Pb phonons. Furthermore, another structure at 8.5 meV that persisted at temperatures above the critical temperature of Pb was attributed to the YBa2Cu3O(7-[delta]) gap. 15 refs., 7 figs.

  17. Applying Freundlich, Langmuir and Temkin models in Cu and Pb soil sorption experiments Uso de los modelos de Freundlich, Langmuir y Temkin en experimentos de sorción de Cu y Pb en suelos Aplicação dos modelos de Freundlich, Langmuir e Temkin em ensaios de sorção de Cu e Pb no solo

    Directory of Open Access Journals (Sweden)

    F.A. Vega

    2011-11-01

    Full Text Available

    In acid soils, inputs of Cu and Pb of various origins create a high risk of environmental pollution. For this reason, batch experiments on Cu and Pb sorption and desorption in various horizons of three acid soils were performed on soil pH with 0.01 M NaNO3 as background electrolyte. The objectives were to evaluate Cu and Pb sorption and retention capacity through the Langmuir, Freundlich and Temkin equations parameters fitted to the sorption/desorption data; to determine the coherence of the implications of these parameters; and to estimate the role of various soil characteristics in the Cu and Pb immobilization soil capacity. The results confirmed the suitability of the models parameters for studying Cu and Pb sorption and retention by acid soils. The greatest maximum sorption and retention capacities, indicated by the Langmuir parameter ßL, corresponded to the lowest energy values required for fixation, indicated by the Temkin parameter b’. Together with the Freundlich parameter KF, which indicates sorption and retention capacity, they made it possible to infer that the acid soil component that most influences Cu and Pb immobilization was the organic matter, followed by the Al-oxide content. High organic matter and Al-oxide contents, especially the former, gave rise to a lower energy requirement for the immobilization of metal cations, since they increased the soils’ sorption and retention capacities. Al3+, the dominant cation in the exchange complex in the horizons studied, and K+ are responsible for the influence of CECe on Cu and Pb immobilization in the acid soils studied.

    El aporte de Cu y Pb a través de diversas fuentes a suelos ácidos supone un alto riesgo de contaminación medioambiental. Por ello, usando el método batch y con NaNO3 0,01 M como electrolito de fondo, se llevaron a cabo, al

  18. Enhanced photocurrent ZnO/CdS/CuInSe/sub 2/ solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Potter, R.R.

    1986-02-01

    The short-wavelength spectral response of a thin film CuInSe/sub 2/ device is improved by a thin (less than 500 A) undoped CdS layer and a 1 micron ZnO conducting window layer. The ZnO acts as an antireflection coating and permits photons of wavelength above 360 nm to be absorbed in the CuInSe/sub 2/. A 25-percent photocurrent enhancement is measured for comparable devices. Total area efficiencies over 9 percent are achieved under AM 1.5 illumination. Current-voltage, capacitance-voltage, and spectral response data are discussed. The data indicate that device properties are similar to devices with (In)CdS window layers. A reverse bias breakdown with long time constants is observed. Deep states in the thin CdS layer may be responsible.

  19. Enhanced photocurrent ZnO/CdS/CuInSe/sub 2/ solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Potter, R.R.

    1986-01-15

    The short-wavelength spectral response of a thin film CuInSe/sub 2/ device is improved by a thin (<500 A) undoped CdS layer and a 1 ..mu..m ZnO conducting window layer. The ZnO acts as an antireflection coating and permits photons of wavelength above 360 nm to be absorbed in the CuInSe/sub 2/. A 25% photocurrent enhancement is measured for comparable devices. Total area efficiencies over 9% are achieved under AM 1.5 illumination. Current-voltage, capacitance-voltage and spectral response data are discussed and indicate that device properties are similar to devices with (In) CdS window layers. A reverse bias breakdown with long time constants is observed. Deep states in the thin CdS layer may be responsible.

  20. Thin film CdS/Cu/sub 2/S solar cells by chemical spraying

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, J.F.

    1976-12-15

    This project involves further work on a process developed to make very thin film CdS/Cu/sub 2/S solar cells. The process is adapted to the float glass process and consists of spraying suitable chemicals on a moving ribbon of glass which floats on a bath of molten metal. The spraying produces the necessary thin films (with suitable optical and electrical properties) of SnO/sub 2/, CdS and Cu/sub 2/S. The CdS films produced are two to three microns thick, thus conserving the use of cadmium. The estimated cost per peak watt is approximately 7 cents (1975 costs) at 5 percent efficiency and an output of 37.6 x 10/sup 6/ square meters annually. The cells are blackwall cells. A float glass plant modified for the process is shown schematically. Research progress is described.

  1. Assessment of Cu, Pb and Hg Contamination in Bottom Sediments Of Surface Water in XuZhou

    Institute of Scientific and Technical Information of China (English)

    王晓; 韩宝平; 朱雪强

    2004-01-01

    Pollution of heavy metals Cu,Pb and Hg is assessed using geo-accumulation index in this paper. The result shows that the bottom sediments of surface water in Xuzhou is polluted by these heavy metals to deferent degrees, of which the Jinma River is the most serious, and then the Kuihe River, the abandoned Yellow River, and the Jinghang Canal. The Yunlong Lake has also been polluted by Hg. The three kinds of heavy metals in the order of concentration is Hg>Cu>Pb. The pollution degree and the type of element is closely related with industrial structure in Xuzhou.

  2. Atmospheric Deposition-Carried Pb,Zn,and Cd from a Zinc Smelter and Their Effect on Soil Microorganisms

    Institute of Scientific and Technical Information of China (English)

    YANG Yuan-Gen; JIN Zhi-Sheng; BI Xiang-Yang; LI Fei-Li; SUN Li; LIU Jie; FU Zhi-You

    2009-01-01

    Dust emissions from smelters,as a major contributor to heavy metal contamination in soils,could severely influence soil quality.Downwind surface soils within 1.5 km of a zinc smelter,which was active for 10 years but ceased in 2000,in Magu Town,Guizhou Province,China were selected to examine Pb,Zn,and Cd concentrations and their fractionation along a distance gradient from a zinc smelter,and to study the possible effects of Pb,Zn,and Cd accumulation on soil microorganisms by comparing with a reference soil located at a downwind distance of 10 km from the zinc smelter.Soils within 1.5 km of the zinc smelter accumulated high levels of heavy metals Zn (508 mg kg-1),Pb (95.6 mg kg-1),and Cd (5.98 mg kg-2) with low ratios of Zn/Cd (59.1-115) and Pb/Cd (12.4-23.4).Composite pollution indices (CPIs) of surface soils (2.52-15.2) were 3 to 13 times higher than the reference soils.In metal accumulated soils,exchangeable plus carbonate-bound fractions accounted for more than 10% of the total Zn,Pb,and Cd.The saturation degree of metals (SDM) in soils within 1.5 km of the smelter (averaging 1.25) was six times higher than that of the reference soils (0.209).A smaller soil microbial biomass was found more frequently in metal accumulated soils (85.1-438 μg C g-1) than in reference soils (497 μg C g-1),and a negative correlation (P < 0.01) of soil microbial biomass carbon to organic carbon ratio (Cmic/Corg) with SDM was observed.Microbial consumption of carbon sources was more rapid in contaminated soils than in reference soils,and a shift in the substrate utilization pattern was apparent and was negatively correlated with SDM (R =-0.773,P < 0.01).Consequently,dust deposited Pb,Zn,and Cd in soils from zinc smelting were readily mobilized,and were detrimental to soil quality mainly in respect of microbial biomass.

  3. Genesis of Pb-Zn-Cu-Ag Deposits within Permian Carboniferous-Carbonate Rocks in Madina Regency, North Sumatra

    Directory of Open Access Journals (Sweden)

    Bhakti Hamonangan Harahap

    2015-11-01

    Full Text Available Strong mineralized carbonate rock-bearing Pb-Zn-Cu-Ag-(Au ores are well exposed on the Latong River area, Madina Regency, North Sumatra Province. The ore deposit is hosted within the carbonate rocks of the Permian to Carboniferous Tapanuli Group. It is mainly accumulated in hollows replacing limestone in the forms of lensoidal, colloform, veins, veinlets, cavity filling, breccia, and dissemination. The ores dominantly consist of galena (126 000 ppm Pb and sphalerite (2347 ppm Zn. The other minerals are silver, azurite, covellite, pyrite, marcasite, and chalcopyrite. This deposit was formed by at least three phases of mineralization, i.e. pyrite and then galena replaced pyrite, sphalerite replaced galena, and pyrite. The last phase is the deposition of chalcopyrite that replaced sphalerite. The Latong sulfide ore deposits posses Pb isotope ratio of 206Pb/204Pb = 19.16 - 20.72, 207Pb/204Pb = 16.16 - 17.29, and 208Pb/204Pb = 42.92 - 40.78. The characteristic feature of the deposit indicates that it is formed by a sedimentary process rather than an igneous activity in origin. This leads to an interpretation that the Latong deposit belongs to the Sedimentary Hosted Massive Sulfide (SHMS of Mississippi Valley-Type (MVT. The presence of SHMS in the island arc such as Sumatra has become controversial. For a long time, ore deposits in the Indonesian Island Arc are always identical with the porphyry and hydrothermal processes related to arc magmatism. This paper is dealing with the geology of Latong and its base metal deposits. This work is also to interpret their genesis as well as general relationship to the regional geology and tectonic setting of Sumatra.

  4. Co-adsorption of Cu and Pb on the Si(1 1 1)-(7 × 7) surface: interface formation

    Science.gov (United States)

    Shukrinov, Pavel; Mutombo, Pingo; Cháb, Vladimír.; Prince, K. C.

    2003-06-01

    The adsorption of Cu and Pb atoms on a Si(1 1 1)-7 × 7 surface was studied by means of scanning tunnelling microscopy (STM). After deposition of ⩽0.1 monolayer (ML) of copper on the Pb √3×√3 mosaic phase and a subsequent annealing up to ˜373 K, new objects of a hexagonal shape appear on a surface. They are scattered over the surface and localised next to the mosaic phase islands. The difference between atomically resolved images of filled and empty states suggests strong covalent bonding within a hexagon. Increasing the concentration of Cu atoms leads to an increasing number of hexagons and their agglomeration. Annealing of this surface at a higher temperature (>470 K) leads to the transformation of these hexagonal-like objects and their agglomeration into the pseudo-"5 × 5" structure, commonly observed for the Cu/Si(1 1 1)system. The absence of hexagons at very low Cu concentration demonstrates the presence of a long-range, attractive interaction among Cu atoms and their strong diffusion just above room temperature (RT).

  5. Heavy metal content (Cd, Ni, Cr and Pb) in soil amendment with a low polluted biosolid

    Science.gov (United States)

    Gomez Lucas, Ignacio; Lag Brotons, Alfonso; Navarro-Pedreño, Jose; Belén Almendro-Candel, Maria; Jordán, Manuel M.; Bech, Jaume; Roca, Nuria

    2016-04-01

    The progressively higher water quality standards in Europe has led to the generation of large quantities of sewage sludge derived from wastewater treatment (Fytili and Zabaniotou 2008). Composting is an effective method to minimize these risks, as pathogens are biodegraded and heavy metals are stabilized as a result of organic matter transformations (Barker and Bryson 2002; Noble and Roberts 2004). Most of the studies about sewage sludge pollution are centred in medium and high polluted wastes. However, the aim of this study was to assess the effects on soil heavy metal content of a low polluted sewage sludge compost in order to identify an optimal application rate based in heavy metal concentration under a period of cultivation of a Mediterranean horticultural plant (Cynara carducnculus). The experiment was done between January to June: rainfall was 71 mm, the volume of water supplied every week was 10.5 mm, mean air temperatures was 14.2, 20.4 (maximum), and 9.2◦C (minimum). The soil was a clay-loam anthrosol (WRB 2006). The experimental plot (60 m2) was divided into five subplots with five treatments corresponding to 0, 2, 4, 6, and 8 kg compost/m2. Three top-soil (first 20 cm) samples from each treatment were taken (January, April and June) and these parameters were analysed: pH, electrical conductivity, organic matter and total content of heavy metals (microwave acid digestion followed by AAS-spectrometry determination). The results show that sewage sludge compost treatments increase the organic matter content and salinity (electrical conductivity of the soils) and diminish the pH. Cd and Ni total content in top-soil was affected and both slightly reduce their concentration. Pb and Cr show minor changes. In general, the application of this low polluted compost may affect the mobility of Cd and Ni due to the pH modification and the water added by irrigation along time but Pb and Cr remain their content in the top-soil. References Barker, A.V., and G.M. Bryson

  6. Ion beam synthesis of CdS, ZnS, and PbS compound semiconductor nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    White, C.W.; Budai, J.D.; Meldrum, A.L. [and others

    1997-12-01

    Sequential ion implantation followed by thermal annealing has been used to form encapsulated CdS, ZnS, and PbS nanocrystals in SiO{sub 2} and Al{sub 2}O{sub 3} matrices. In SiO{sub 2}, nanoparticles are nearly spherical and randomly oriented, and ZnS and PbS nanocrystals exhibit a bimodal size distribution. In Al{sub 2}O{sub 3}, nanoparticles are faceted and coherent with the matrix. Initial photoluminescence (PL) results are presented.

  7. Microstructural evolution and tensile properties of Sn-Ag-Cu mixed with Sn-Pb solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fengjiang [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States); O' Keefe, Matthew [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States)], E-mail: mjokeefe@mst.edu; Brinkmeyer, Brandon [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States)

    2009-05-27

    The effect of incorporating eutectic Sn-Pb solder with Sn-3.0Ag-0.5Cu (SAC) Pb-free solder on the microstructure and tensile properties of the mixed alloys was investigated. Alloys containing 100, 75, 50, 25, 20, 15, 10, 5 and 0 wt% SAC, with the balance being Sn-37Pb eutectic solder alloy, were prepared and characterized. Optical and scanning electron microscopy were used to analyze the microstructures while 'mini-tensile' test specimens were fabricated and tested to determine mechanical properties at the mm length scale, more closely matching that of the solder joints. Microstructural analysis indicated that a Pb-rich phase formed and was uniformly distributed at the boundary between the Sn-rich grains or between the Sn-rich and the intermetallic compounds in the solder. Tensile results showed that mixing of the alloys resulted in an increase in both the yield and the ultimate tensile strength compared to the original solders, with the 50% SAC-50% Sn-Pb mixture having the highest measured strength. Initial investigations indicate the formation and distribution of a Pb-rich phase in the mixed solder alloys as the source of the strengthening mechanism.

  8. Compositional and electrical analysis of the multilayers of a CdS/CuInSe/sub 2/ solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Noufi, R.; Dick, J.

    1985-11-15

    The compositional profiles and the electrical properties of the bilayers of CdS and CuInSe/sub 2/ films in CdS/CuInSe/sub 2/ solar cells are presented and compared with those of the individual layers alone. The CuInSe/sub 2/ bilayer shows that the two individual layers have mixed, except for the last-to-deposit 0.2--0.4 ..mu..m, which is semi-insulating and copper poor. This bilayer remains p type and highly resistive during the cell processing steps. The CdS bilayer consists of an almost stoichiometric layer close to the junction and a top In-doped low-resistivity layer. The CdS/CuInSe/sub 2/ may possibly operate as a P-S-N device, where the S layer is defined largely by a semi-insulating CuInSe/sub 2/ layer.

  9. Investigation on the efficiency and mechanism of Cd(II) and Pb(II) removal from aqueous solutions using MgO nanoparticles.

    Science.gov (United States)

    Xiong, Chunmei; Wang, Wei; Tan, Fatang; Luo, Fan; Chen, Jianguo; Qiao, Xueliao

    2015-12-15

    In this study, the removal of Cd(II) and Pb(II) from aqueous solutions using MgO nanoparticles prepared by a simple sol-gel method was investigated. The efficiency of Cd(II) and Pb(II) removal was examined through batch adsorption experiments. For the single adsorption of Cd(II) and Pb(II), The adsorption kinetics and isotherm data obeyed well Pseudo-second-order and Langmuir models, indicating the monolayer chemisorption of heavy metal ions. The maximum adsorption capacities calculated by Langmuir equation were 2294 mg/g for Cd(II) and 2614 mg/g for Pb(II), respectively. The adsorption process was controlled simultaneously by external mass transfer and intraparticle diffusion. In the binary system, a competitive adsorption was observed, showing preference of adsorption followed Pb(II) >Cd(II). Significantly, the elution experiments confirmed that neither Cd(II) nor Pb(II) could be greatly desorbed after water washing even for five times. XRD and XPS measurements revealed the mechanism of Cd(II) and Pb(II) removal by MgO nanoparticles was mainly involved in precipitation and adsorption on the surface of MgO, resulting from the interaction between active sites of MgO and heavy metal ions. Easy preparation, remarkable removal efficiency and firmly adsorptive ability make the MgO nanoparticles to be an efficient material in the treatment of heavy metal-contaminated water.

  10. Study of contaminated soils of the abandoned Pb, Zn, Cd Jebel Ressas mine tailings (North eastern Tunisia)

    Science.gov (United States)

    Souissi, R.; Munoz, M.; Souissi, F.; Courjault-Radé, P.; Ben Mammou, A.

    2012-04-01

    Under semi-arid climatic conditions, Pb, Zn and Cd bearing particles are carried by wind and water from the flotation tailing heaps of the former Pb-Zn mine of Jebel Ressas towards the surrounding agricultural areas. The risk of ecotoxicity depends on the phytoaccessible fraction of metals which is closely related to their physico-chemical and biological environment. The objective of this study is to assess the contamination of soils surrounding the waste dumps and to estimate the bioaccessible fraction of metals present in these soils. These silty soils are mainly composed of calcite (45 % CaCO3) and clays. Metal bearing minerals are hemimorphite (Zn4Si2O72H2O), cerussite (PbCO3), and smithsonite (ZnCO3). The flotation tailings display high amounts of Zn, Pb and Cd, averaging 7.11%, 2.30% and 290 mg.kg-1, respectively. The concentrations found in soils reach 6.3% Zn, 2.3% Pb and 290 mg.kg-1 Cd. Such results show that the soils in the mining area are highly contaminated by heavy metals coming from the mining wastes.Analyses of samples taken between surface and bedrock show that Pb and Zn may reach concentrations as high as 900 mg / kg two meters below surface. Three types of simple extraction tests (deionized water, HCl solution at pH 2.8 and a mixture of organic acids (low-molecular-weight organic acids (LMWOAs) at pH 2.8) were performed to assess the phytoaccessibility of Zn, Pb and Cd in two contaminated soil samples collected within the study area. The results of extraction with deionized water showed that only Zn is mobile with 1.50 to 2.92 mg.kg-1 released from soil. During the extraction with HCl 1.32 to 1.63 mg.kg-1 of Pb are released. The extraction with LMWOAs resulted in a much greater leaching of all heavy metals. Indeed, 900 to1500 mg.kg-1 Zn, 33 to 40 mg.kg-1 Pb and 3.5 to 2.01 mg.kg-1 Cd, have been released respectively. Thus, the mobility of these metals is as follows: Zn (2.2%) > Cd (1%) > Pb (0.2%). As a result, the mobilization of contaminants by

  11. Morphological, thermal and optical studies of jute-reinforced PbSrCaCuO-polypropylene composite

    Science.gov (United States)

    Jacob, Reenu; Isac, Jayakumari

    2016-11-01

    New research with modern technologies has always grabbed substantial attention. Conservation of raw materials like natural fibers has helped composite world to explore eco-friendly components. The aim of this paper is to study the potential of jute fiber-reinforced ceramic polymers. Alkali-treated jute fiber has been incorporated in a polypropylene ceramic matrix at different volume fractions. The morphological, thermal and optical studies of jute-reinforced ceramic Pb2Sr2CaCu2O9 (PbSrCaCuO) are studied. Morphological results evidently demonstrate that when the polypropylene ceramic matrix is reinforced with jute fiber, interfacial interaction between the varying proportions of the jute fiber and ceramic composite takes place. TGA and DSC results confirm the enhancement in the thermal stability of ceramic composites reinforced with jute fiber. The UV analysis of the composite gives a good quality measure on the optical properties of the new composite prepared.

  12. Thermally-restorable optical degradation and the mechanism of current transport in Cu2S-CdS photovoltaic cells

    Science.gov (United States)

    Fahrenbruch, A. L.; Bube, R. H.

    1974-01-01

    The photovoltaic properties of single-crystal Cu2S-CdS heterojunctions have been investigated as a function of heat treatment by detailed measurements of the dependence of short-circuit current on photon energy, temperature, and the state of optical degradation or enhancement. A coherent picture is formulated for the relationship between enhancement and optical degradation, and their effect on the transport of short-circuit photoexcited current and dark, forward-bias current in the cell. Optical degradation in the Cu2S-CdS cell is shown to be closely identical to optical degradation of lifetime in a homogeneous CdS:Cd:Cu crystal, indicating that the CdS:Cu layer near the junction interface controls carrier transport in the cell. It is proposed that both the photoexcited short-circuit current and the dark, forward-bias current are controlled by a tunneling-recombination process through interface states.

  13. Effect of Zn, Cu, Cr and Pb Chlorides on the Formation of Tricalcium Aluminate Trisulfate Hydrate

    Institute of Scientific and Technical Information of China (English)

    Wafaa S.Hegazi; Eisa E.Hekal; Essam A.Kishar; Maha R.Mohammed

    2008-01-01

    The effect of addition of Zn,Cu,Pb and Cr chlorides as admixtures on the hydration reaction of the system 3CaO·Al2O3-gypsum with molar ratio 1:3 was studied.Different ratios of each salt were used,namely 0.5%,2% and 4% by weight of the solid mixture.Hydration reaction was carried out at 35℃ for various time intervals from 0.5 h to up to 7 d.Hydration rate of the system 3CaO-Al2O3-CaSO4·2H2O in absence and presence of different salts was studied via the determination of the combined water contents.X-ray diffraction analysis showed that the ettringite was the only hydration product formed in the different mixes.The hydration products were investigated by scanning electron microscopy (SEM) and thermal gravimetric analysis.The results indicated that the rate of formation of ettringite and its microstructure depend on the admixture and its dosage.

  14. Swift heavy ion irradiation effect on Cu-doped CdS nanocrystals embedded in PMMA

    Indian Academy of Sciences (India)

    Shweta Agrawal; Subodh Srivastava; Sumit Kumar; S S Sharma; B Tripathi; M Singh; Y K Vijay

    2009-12-01

    Semiconductor nanocrystals (NCs) have received much interest for their optical and electronic properties. When these NCs dispersed in polymer matrix, brightness of the light emission is enhanced due to their quantum dot size. The CdCuS NCs have been synthesized by chemical route method and then dispersed in PMMA matrix. These nanocomposite polymer films were irradiated by swift heavy ion (SHI) (100 MeV, Si+7 ions beam) at different fluences of 1 × 1010 and 1 × 1012 ions/cm2 and then compared their structural and optical properties by XRD, atomic force microscopy, photoluminescence, and UV-Vis spectroscopy before and after irradiation. The XRD spectra showed a broad hump around 2 ≈ 11.83° due to amorphous PMMA and other peaks corresponding to hexagonal structure of CdS nanocrystals in PMMA matrix. The photoluminescence spectra shows a broad peak at 530 nm corresponding to green emission due to Cu impurities in CdS. The UV-Vis measurement showed red shift in optical absorption and bandgap changed from 4.38–3.60 eV as the irradiation fluency increased with respect to pristine CdCuS nanocomposite polymer film.

  15. Humic substances from sewage sludge compost as washing agent effectively remove Cu and Cd from soil.

    Science.gov (United States)

    Kulikowska, Dorota; Gusiatin, Zygmunt Mariusz; Bułkowska, Katarzyna; Kierklo, Katarzyna

    2015-10-01

    Although commercially available biosurfactants are environmentally friendly and effectively remove heavy metals from soil, they are costly. Therefore, this study investigated whether inexpensive humic substances (HS) from sewage sludge compost could effectively remove copper (Cu) and cadmium (Cd) from highly contaminated sandy clay loam (S1) and clay (S2). The optimum HS concentration and pH were determined, as well process kinetics. Under optimum conditions, a single washing removed 80.7% of Cu and 69.1% of Cd from S1, and 53.2% and 36.5%, respectively, from S2. Triple washing increased removal from S1 to almost 100% for both metals, and to 83.2% of Cu and 88.9% of Cd from S2. Triple washing lowered the potential ecological risk (Er(i)) of the soils, especially the risk from Cd. HS substances show potential for treating soils highly contaminated with heavy metals, and HS from other sources should be tested with these and other contaminants.

  16. Effect of Heavy Metals (Cd, Cu) on the Gametophytes of Laminaria japonica Aresch

    Institute of Scientific and Technical Information of China (English)

    Nai-Hao YE; Guang-Ce WANG; Cheng-Kui TSENG

    2005-01-01

    Effects of various concentrations of two heavy metals, namely Cd and Cu, on gametophytes of Laminariajaponica Aresch were determined by recording morphological changes of gametophytes, determining pH values and the heavy metal content of the culture solution, calculating the germination rate of sporophytes, and observing heavy metal (Cd) distribution using a fluorescence microscope. The results showed that heavy metals damaged the gametophytes, and were even lethal, and that the higher the concentration of heavy metal ions, the greater the injury to gametophytes. Gametophytes could not survive in culture solutions containing more than 100 mg/L Cd and 50 mg/L Cu and were only able to survive in culture solution containing a mixture of Cd and Cu up to a concentration of 10 mg/L, which indicates that gametophytes have a higher tolerance to Cd than Cu and that multiple heavy metal ions in solution markedly aggravate the damage to gametophytes compared with individual heavy metal ions. With increases in the concentration of the heavy metal, the burgeoning rate of sporophytes decreased acutely, and solutions containing multiple heavy metal ions caused even more marked harm to sporophytes than solutions containing a single heavy metal ion, because most sporophytes died in mixed solutions. The pH value of the culture medium dropped immediately at the beginning (the first day) of treatment, increased over the following days, and then decreased again. The pH of culture media containing multiple heavy metal ions showed greater variation than media containing a single heavy metal ion, with the extent of the decrease in pH of culture media containing multiple ions being greatest during the last period of the experiment. With increases in the concentration of heavy metals, the capacity of gametophytes to accumulate these ions increased. The blue fluorescent light emitted by the Cd- and Cd-binding protein complex existing in gametophytes in media containing different

  17. [In-situ Study on Effects of Combined Amendment on Translocation Control of Pb and Cd in Soil-Vegetable System].

    Science.gov (United States)

    Zhu, Wei; Liu, Li; Wu, Yan-ming; Zhou, Hang; Deng, Gui-you; Yang, Wen-tao; Peng, Pei-qin; Zeng, Min; Liao, Bo-han

    2015-11-01

    An in-situ study aiming at remedying arid land complexly polluted with Pb and Cd by using combined amendment LS (a mixture of limestone and sepiolite with a ratio of 2 : 1) was conducted in a mining area in southern Hunan, China. The main objectives of this study were to discuss the effects of LS application at different amounts (0 , 2, 4, 8 g x kg(-1)) on the adsorption and accumulation of Pb and Cd in eggplant and amaranth, and to control the translocation and transportation of Pb and Cd among different parts of eggplant and amaranth. The results showed that: (1) Application of LS significantly increased soil pH values and decreased contents of exchangeable Pb and Cd in soil. (2) Application of LS led to an obvious reduction in contents of Pb and Cd in different parts of eggplant and amaranth. Compared with the control group, the contents of Pb and Cd in edible part of eggplant were decreased by 44.7% - 78.6% and 36.0%-78.7%, and those reductions for amaranth were 45.8%-59.1% and 40.0%-87.2%, respectively, when the LS applying ratios ranged 2-8 g x kg(-1). (3) Application of LS reduced the translocation factors of Pb and Cd among different parts of these two kinds of vegetables. The translocation ability of Cd among root, stem, and fruit (in eggplant) or leave (in amaranth) in these two vegetables was greater than that of Pb. However, application of LS with different amounts did not change the sequence of translocation factors of Pb and Cd among different parts of these two kinds of vegetables.

  18. Polycrystalline semiconductor heterojunction modeling (CdS/CuInSe/sub 2/)

    Energy Technology Data Exchange (ETDEWEB)

    Boeer, K.W.

    1986-01-15

    The solution curves of the complete set of transport, continuity and Poisson equations for the CdS/CuInSe/sub 2/ solar cell are analyzed. They show high saturation currents, however, combined with low open-circuit voltage and fill factors. The losses responsible for the low open-circuit voltage are caused by high junction recombination near V/sub oc/ due to the strong optical absorption close to the junction interface in the direct band gap CuInSe/sub 2/ with little light penetrating towards the back electrode. A consequently stepwise parameter variation identifies the importance of an increase in minority carrier life and acceptor density in the CuInSe/sub 2/ which, when combined, improves V/sub oc/ from 350 to more than 500 mV. A shift of the junction away from the CdS/CuInSe/sub 2/ interface into the CuInSe/sub 2/ shows a reduction in the field at the hetero-interface which results in marked losses in short-circuit currents when the interface recombination velocity exceeds about 10/sup 5/ cm s/sup -1/. The results of the computation demonstrate the sensitivity of the cell design to several factors including doping, recombination center distribution and boundary conditions to interlayers between the active device part and the electrodes.

  19. Changes of Cu, Zn, and Cd speciation in sewage sludge during composting

    Institute of Scientific and Technical Information of China (English)

    GAO Ding; ZHENG Guo-di; CHEN Tong-bin; LUO Wei; GAO Wei; ZHANG Yi-an; LI Yan-xia

    2005-01-01

    The potential toxicity risks from heavy metals depend on their chemical speciation. The four stages of the Tessier sequential extraction method were employed to investigate changes in heavy metal speciation(Cu, Zn, and Cd) of sewage sludge during forced aeration composting, and then to identify whether the composting process would reduce or enhance their toxicities. Throughout the composting process, the exchangeable, carbonate-bound, Fe-Mn oxide-bound, and organic matter-bound fractions of Cu were converted to the residual Cu fraction. The organic matter-bound Cu fraction greatly contributed to this transformation. Residual Zn fraction was transformed to the Fe-Mn oxide-bound and organic matter-bound fractions after composting. The residual Zn fraction was a major contributor to the organic matter-bound Zn fraction. The availability of Cu and Zn was reduced by composting such that the risk of heavy metal toxicity decreased with prolonged treatment times. Additionally, attention should be paid to the increased availability of Cd in sewage sludge after composting treatment.

  20. sup 119 Sn-Moessbauer spectroscopic study of the single phase of Bi(Pb)-Sr-Ca-Cu(Sn)-O

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Y. (Dept. of Electrical Engineering, Fukuoka Univ. (Japan)); Nishida, T. (Dept. of Chemistry, Kyushu Univ., Fukuoka (Japan)); Katada, M. (Dept. of Chemistry, Tokyo Metropolitan Univ. (Japan)); Deshimaru, Y.; Miura, N.; Yamazoe, N. (Dept. of Materials Science and Tech., Graduate School of Engineering Sciences, Kyushu Univ., Fukuoka (Japan))

    1991-12-01

    Tin-doped samples of the high-Tc (2223) phase of Bi-Pb-Sr-Ca-Cu-O superconductor have been prepared by a conventional sintering method. Sintering conditions were carefully selected to obtain the single high-Tc phase. {sup 119}Sn-Moessbauer spectra have been measured in the temperature range from 4.2 to 300 K. The temperature dependence of the recoilless fraction (f) is well understood by the temperature dependence of the normal phonon. (orig.).

  1. Concentration of Zn, Cu and Pb in Some Selected Marine Fishes of the Pahang Coastal Waters, Malaysia

    Directory of Open Access Journals (Sweden)

    B. Y. Kamaruzzaman

    2010-01-01

    Full Text Available Problem statement: Heavy metals constitute one of the most hazardous substances that could be accumulated in biota. Fish populations exploited by man often live in coastal area environments that contain high levels of heavy metals, coming from human activities such as industrial and agricultural wastes. A problem to deal when using fishes as biomonitors of heavy metals is the relationship existing between metal concentration and several intrinsic factors of the fish such as organism size, genetic composition and age of fish. Approach: Concentration of Zn, Cu and Pb were determined in eight commercially valuable fish species, Selaroides leptolepis, Euthynnus affinis, Parastromateus niger, Lutjanius malabaricus, Epinephelus sexfasciatus, Rastrelliger kanagurta, Nemipterus japonicus and Megalaspis cordyla from Pahang coastal water. The concentration was measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS. The study focuses on the level of Zn, Cu and Pb in order to assess the environmental pollution by using fishes as an indicator. Results: Concentrations of the heavy metals in examined fish species ranged as follow: Zn 19.27 µg g-1 dry weight; Cu 2.88 µg g-1 dry weight and Pb 0.26 µg g-1 dry weight, respectively. The concentrations of Zn, Cu and Pb were found to follow the order: stomach > muscle > gills. Significant correlations were found between fish weight and heavy metals concentration in the fish organs. Conclusion: The estimated values of all metals in muscles of fish in this study were below the established values. Therefore, it can be concluded that the fish from Pahang coastal water are comparatively clean and do not constitute a risk for human health.

  2. A Study on the Effect of Ni Dopping on Bi-Pb-Sr-Ca-Cu-O System

    OpenAIRE

    ABUKAY, Mustafa TEPE and Doğan

    1998-01-01

    The effect of Ni doping on superconductivity properties of the