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Sample records for cu pb cd

  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. Speciation and behaviour of Cd, Pb and Cu in Zuari Estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    George

    Dissolved labile and nonlabile forms of Cd, Pb and Cu in Zuari Estuary, Goa, India measured for a period of 14 months showed lowest concentrations during the SW monsoon (June-September) while maximum concentrations were observed during...

  4. (Cd, Cu, Ni and Pb) content in two fish species of Persian Gulf in ...

    African Journals Online (AJOL)

    GREGORY

    2010-09-13

    Sep 13, 2010 ... Heavy metal (HMs) pollution of aquatic environment has become a great concern in recent years. ... study, cadmium (Cd), copper (Cu), nickel (Ni) and lead (Pb) levels ... toxic effects on organs (Macfarlane and Burchettt 2000).

  5. Distribution of various forms of Cd, Pb and Cu in the Wadge Bank region (Arabian Sea)

    Digital Repository Service at National Institute of Oceanography (India)

    George, M.D.

    Labile, nonlabile and particulate forms of Cd,Pb and Cu were determined in 29 water samples collected from a depth of 5 m, from the Wadge Bank area. Labile Cd varied from 0.1 to 0.2 mu g.l-1 while nonlabile fraction was in the range 0.1 to 0.3 mu gl...

  6. 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.

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

    Science.gov (United States)

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

    2015-10-01

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

  8. Assessing the Levels of Pb, Cd, Zn and Cu in Biscuits and Home ...

    African Journals Online (AJOL)

    ADOWIE PERE

    The mean levels of Zn, Cu, Pb and Cd found in plantain chips obtained from the University ... the upper limits of the range specified by the World Health Organization, the consumption of .... 0.52 mg/kg) in potato chips sampled from the second.

  9. 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...

  10. 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.

  11. ASSESSMENT OF Pb, Cd, Cu AND Zn AVAILABILITY FOR PLANTS IN BAIA MARE MINING REGION

    Directory of Open Access Journals (Sweden)

    LEVEI ERIKA-ANDREA

    2010-12-01

    Full Text Available In order to evaluate the mobility of heavy metals in soil from Baia Mare mining region, the total, water and DTPA extractable metal contents were determined. The results showed that despite the high total metals contents and the high percentages of plant available metals only a low percent was water soluble, indicating a potential accumulation of metals in trophic chain and a potential risk for public health. Among the investigated metals, the plant available Pb and Cd species are the most severe contaminants. Significant correlations between total and DTPA extractable metals were found for Cu (r=0.510 and Pb (0.418, and also an affinity between total and water extractable metals were identified for Cu (0.366, Pb (0.502 and Zn (0.597.

  12. 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

  13. 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 ...

  14. 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.

  15. [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.

  16. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. 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....

  18. 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.

  19. 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.

  20. 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+.

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

    Science.gov (United States)

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

    2016-02-01

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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Modelling the concentrations of dissolved contaminants (Cd, Cu, Ni, Pb, Zn) in floodplain soils.

    Science.gov (United States)

    Rennert, Thilo; Rabus, Widar; Rinklebe, Jörg

    2017-04-01

    Central European floodplain soils are often contaminated with potentially toxic metals. The prediction of their aqueous concentrations is a prerequisite for an assessment of environmental concerns. We tested the aqueous concentrations of cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) derived from multi-surface adsorption modelling (on hydrous iron, aluminum and manganese oxides, clay and soil organic matter) against those analyzed in situ in the soil solution of four horizons of floodplain soils at the Elbe River, Germany. The input data for the reactive metals were derived from a seven-step sequential extraction scheme or from extraction with 0.43 M nitric acid (HNO3) and evaluated in four modelling scenarios. In all scenarios, measured and modelled concentrations were positively related, except partially for Pb. Close reproduction of the measured data was obtained using measured data of accompanying cations and anions together with amounts of reactive metals from both the sequential extraction or from 0.43 M HNO3 extraction, except for Cu, which was often strongly overestimated, and partially Cd. We recommend extraction with 0.43 M HNO3 to quantify reactive metals in soil because the modelling results were metal-specific with better or equal results using the single extractant, the application of which is also less laborious. Approximations of ion concentrations and water contents yielded similar results. Modelled solid-phase speciation of metals varied with pH and differed from that from sequential extraction. Multi-surface modelling may be an effective tool to predict both aqueous concentrations and solid-phase speciation of metals in soil.

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

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    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.

  15. 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

  16. 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

  17. 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.

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

    Science.gov (United States)

    Nimmo, Malcolm; Fones, Gary R.

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

  19. 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.

  20. 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)

  1. 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

  2. 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

  3. [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.

  4. 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.

  5. 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.

  6. 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.

  7. 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+.

  8. Multi-metal interactions between Cd, Cu, Ni, Pb and Zn in water flea Daphnia magna, a stable isotope experiment.

    Science.gov (United States)

    Komjarova, I; Blust, R

    2008-11-11

    Metal interaction effects were investigated in Daphnia magna during a simultaneous exposure to essential (Cu, Ni and Zn) and non-essential (Cd and Pb) metals at environmentally relevant concentrations using a stable isotope technique. The metals were applied in the following concentration ranges: 0.0125-0.2 microM for (106)Cd, 0.025-0.25 microM for (65)Cu and (204)Pb, 0.1-1.25 microM for (62)Ni and (67)Zn. Cadmium and copper exhibited a suppressing effect on the uptake rates of all other metals present in the mixture with the exception to lead at all studied concentrations. The effect was already pronounced at low Cd and Cu concentrations and reached a maximum at the higher concentrations. Nickel and zinc showed weaker interactions with cadmium and between each other, while having no effect on copper and lead uptake. There was a high degree of correlation between Cd, Ni and Zn uptake rates indicating that these metals share in part common uptake or interaction pathways. Moreover, a significant correlation between Zn and Cu uptake processes suggests that more than one mechanism is involved in Zn accumulation since Cu is known to interact with Na uptake sites. The uptake of lead was marked by a high initial rate, but the uptake process reached saturation within 24 h. Cd applied at a concentration of 0.2 microM was the only metal which affected the lead uptake process by stimulation of the Pb uptake. Added to the medium at a concentration of 0.25 microM, lead in turn, increased copper uptake. Current work illustrates that metal interactions are significant and occur at low environmentally realistic concentrations affecting bioavailability of both toxic and essential metals.

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

    Science.gov (United States)

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

    2006-12-01

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

  10. 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.

  11. 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.

  12. Determination of Cd, Pb and Cu in Mandovi estuary by differential pulse anodic stripping voltammetry

    Digital Repository Service at National Institute of Oceanography (India)

    George, M.D.; Sawkar, K.; Reddy, C.V.G.

    0-60% for Pb and 0-80% for Cu. Compared to the reported values from other estuaries, Mandovi estuarine waters have registered a higher concentration of the metals. These high concentrations, to a large extent, are considered to be the effect...

  13. A comparative study on Pb(II), Cd(II), Cu(II)

    African Journals Online (AJOL)

    user

    Co(II) while it decreased in the presence of Cu(II) in the studied range of concentration variation. Maximum Pb(II) .... size variation in the range of 2 to 10 nm. ...... Zinc-bromine Battery, Lead-acid and Lithium Batteries, Arsenic Remediation from.

  14. 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.

  15. 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

  16. 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.

  17. 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.

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

    Science.gov (United States)

    Cui, Shuang; Zhou, Qixing; Chao, Lei

    2007-01-01

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

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. Removal of Pb, Cu, Cd, and Zn Present in Aqueous Solution Using Coupled Electrocoagulation-Phytoremediation Treatment

    Directory of Open Access Journals (Sweden)

    Francisco Ferniza-García

    2017-01-01

    Full Text Available This study presents the results of a coupled electrocoagulation-phytoremediation treatment for the reduction of copper, cadmium, lead, and zinc, present in aqueous solution. The electrocoagulation was carried out in a batch reactor using aluminum electrodes in parallel arrangement; the optimal conditions were current density of 8 mA/cm2 and operating time of 180 minutes. For phytoremediation the macrophytes, Typha latifolia L., were used during seven days of treatment. The results indicated that the coupled treatment reduced metal concentrations by 99.2% Cu, 81.3% Cd, and 99.4% Pb, while Zn increased due to the natural concentrations of the plant used.

  4. Initial biochar properties related to the removal of As, Se, Pb, Cd, Cu, Ni, and Zn from an acidic suspension.

    Science.gov (United States)

    Clemente, Joyce S; Beauchemin, Suzanne; MacKinnon, Ted; Martin, Joseph; Johnston, Cliff T; Joern, Brad

    2017-03-01

    This study tests the influence of a diverse set of biochar properties on As(V), Se(IV), Cd(II), Cu(II), Ni(II), Pb(II), or Zn(II) removal from solution at pH 4.5. Six commercial biochars produced using different feedstock and pyrolysis conditions were extensively characterized using physical, chemical, and spectroscopic techniques, and their properties were correlated to anion and cation removal using multiple linear regression. H/total organic C (TOC) ratio and volatile matter were positively correlated to cation removal from solution, which indicate interactions between metals and non-aromatic C. Defining the correlation of ion removal with specific OC functional groups was hindered by the inherent limitations of the spectroscopic techniques, which was exacerbated by the heterogeneity of the biochars. Ash was negatively correlated to Se(IV) and positively correlated to Cd(II), Cu(II), and Ni(II) removal from solution. Interference from soluble P in biochars may partly explain the low Se(IV) removal from solution; and Ca-, P-, and Fe- containing compounds likely sorbed or precipitated Pb(II), Cd(II), Cu(II), Ni(II) and Zn(II). Furthermore, Ca-oxalate identified using X-ray diffraction in willow, may be responsible for willow's increased ability to remove Cd(II), Ni(II), and Zn(II) compared to the other 5 biochars. It was clear that both OC and inorganic biochar components influenced metal(loid) and Se(IV) removal from solution. The non-aromatic and volatile OC correlated to removal from solution may be readily available for microbial degradation, while Mg, N, P, and S are required for biological growth. Biological metabolism and uptake of these compounds may inhibit or destabilize their interaction with contaminants. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  5. 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.

  6. Trace metals (Cu, Zn, Cd and Pb in juvenile fish from estuarine nurseries along the Portuguese coast

    Directory of Open Access Journals (Sweden)

    Rita P. Vasconcelos

    2011-02-01

    Full Text Available Organic and inorganic pollution can impact organisms directly and affect condition, growth and survival of juvenile fish which use estuaries as nurseries, and thereby affect marine adult populations quantitatively and qualitatively. Trace element contamination (Cu, Zn, Cd, Pb in juveniles of commercial fish Solea solea, Solea senegalensis, Platichthys flesus, Diplodus vulgaris and Dicentrarchus labrax collected in putative nurseries of the main Portuguese estuaries (with diverse intensities and sources of anthropogenic pressures was determined via atomic absorption spectrometry. Contamination was significantly different among species. Similar levels of contamination were found among estuaries, except for D. vulgaris. Cu and Zn concentrations ranged from 1.0 to 2.1 and 14 to 59 μg g-1 muscle dry weight respectively; while Cd and Pb concentrations were very low. The results indicate that juvenile migration to off-shore habitats is associated with low export of contamination, and no particular estuary increases the potential contamination of adult stocks. This knowledge is of the utmost importance in view of the ecological and economical value of these species and their use of estuarine areas as nurseries.

  7. 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

  8. 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.

  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. 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⁺. ...

  11. 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.

  12. 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.

  13. Effect of bamboo and rice straw biochars on the mobility and redistribution of heavy metals (Cd, Cu, Pb and Zn) in contaminated soil.

    Science.gov (United States)

    Lu, Kouping; Yang, Xing; Gielen, Gerty; Bolan, Nanthi; Ok, Yong Sik; Niazi, Nabeel Khan; Xu, Song; Yuan, Guodong; Chen, Xin; Zhang, Xiaokai; Liu, Dan; Song, Zhaoliang; Liu, Xingyuan; Wang, Hailong

    2017-01-15

    Biochar has emerged as an efficient tool to affect bioavailability of heavy metals in contaminated soils. Although partially understood, a carefully designed incubation experiment was performed to examine the effect of biochar on mobility and redistribution of Cd, Cu, Pb and Zn in a sandy loam soil collected from the surroundings of a copper smelter. Bamboo and rice straw biochars with different mesh sizes (Heavy metal concentrations in pore water were determined after extraction with 0.01 M CaCl2. Phytoavailable metals were extracted using DTPA/TEA (pH 7.3). The European Union Bureau of Reference (EUBCR) sequential extraction procedure was adopted to determine metal partitioning and redistribution of heavy metals. Results showed that CaCl2-and DTPA-extractable Cd, Cu, Pb and Zn concentrations were significantly (p extractable metal concentrations (p extraction procedure revealed that the acid extractable fractions of Cd, Cu, Pb and Zn decreased significantly (p extractable metal fractions, and the effect was more pronounced with increasing biochar application rate. The effect of biochar particle size on extractable metal concentrations was not consistent. The 5% rice straw biochar treatment reduced the DTPA-extractable metal concentrations in the order of Cd extractable pool of Cd, Cu, Pb and Zn by 11, 17, 34 and 6%, respectively, compared to the control. In the same 5% rice straw biochar treatments, the organic bound fraction increased by 37, 58, 68 and 18% for Cd, Cu, Pb and Zn, respectively, compared to the control, indicating that the immobilized metals were mainly bound in the soil organic matter fraction. The results demonstrated that the rice straw biochar can effectively immobilize heavy metals, thereby reducing their mobility and bioavailability in contaminated soils. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. 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…

  15. Evaluation of Cd, Cr, Cu, Ni, and Pb in selected cosmetic products from Jordanian, Sudanese, and Syrian markets.

    Science.gov (United States)

    Massadeh, A M; El-Khateeb, M Y; Ibrahim, S M

    2017-08-01

    There is no sufficient data that evaluate heavy metal content in cosmetic products in Jordan as well as Sudan and Syria. This study aims to assess metal levels which include Cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni), and Lead (Pb) in cosmetic products. These elements have draft limits because they are identified as potential impurities and are known to be toxic. This study aims to provide information to the population that may be beneficial to public health. Samples were collected from different brands obtained from markets in Jordan, Sudan, and Syria. Some of the selected cosmetic products were eyeliner, eye pencil, mascara, lipstick, powder, face cream, body cream, sun block, Vaseline, and the traditional eye cosmetic (kohl). The heavy metal content in these samples were determined by atomic absorption spectrometry (AAS). Based on analysis of variance analysis, a significant difference in heavy metal levels was found for samples obtained from Jordanian and Sudanese markets. The acid digestion method used in this study was based on procedures recommended by Nnorom et al. with some modifications as follows. (i) A weight of 2.0 g of cosmetic sample was dissolved in a mixture of 6 mL of high quality concentrated 69% nitric acid (HNO3; Merck, Darmstadt, Germany) and 4 mL of concentrated 37% hydrochloric acid (Scharlau, Spain) in a porcelain crucible and heated on a hotplate to near dryness. (ii) An aliquot of 15 mL HNO3 (1.00 M) was added to the digested sample and filtered through a Whatman No. 40 filter paper. (iii) The digested sample was transferred quantitatively into a 25 mL volumetric flask and then diluted with deionized water. (iv) Each digested sample was evaporated at 70 °C to about 1 mL and transferred into a polyethylene flask and diluted with 25 mL deionized water. (v) Blank was treated in the same procedure. In Jordan the concentration ranges of heavy metals in the collected samples were: Cd (0.03-0.10 μg/g), Cr (0.0-1.00

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

    Energy Technology Data Exchange (ETDEWEB)

    Nastasović, Aleksandra B., E-mail: anastaso@chem.bg.ac.rs [University of Belgrade, Institute of Chemistry Technology and Metallurgy, Department of Chemistry, Department of Microelectronic Technologies, Njegoševa 12, Belgrade (Serbia); Ekmeščić, Bojana M. [University of Belgrade, Institute of Chemistry Technology and Metallurgy, Department of Chemistry, Department of Microelectronic Technologies, Njegoševa 12, Belgrade (Serbia); and others

    2016-11-01

    Highlights: • Macroporous PGME-deta sorption potential for Pb(II), Cd(II) and Cu(II) was studied. • Sorption kinetics obeyed pseudo-second order model. • Maximal Pb(II), Cd(II) and Cu(II) sorption capacities were 164, 152 and 120 mg g{sup −1}. • AFM indicates that metal sorption changes the size and morphology of PGME-deta. • XPS suggests complexation through the formation of Me−O and Me−N bonds in PGME-deta. - Abstract: 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.

  19. 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.

  20. 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.

  1. Evaluating the potential of three Fe- and Mn-(nano)oxides for the stabilization of Cd, Cu and Pb in contaminated soils.

    Science.gov (United States)

    Michálková, Zuzana; Komárek, Michael; Šillerová, Hana; Della Puppa, Loïc; Joussein, Emmanuel; Bordas, François; Vaněk, Aleš; Vaněk, Ondřej; Ettler, Vojtěch

    2014-12-15

    The potential of three Fe- and Mn-(nano)oxides for stabilizing Cd, Cu and Pb in contaminated soils was investigated using batch and column experiments, adsorption tests and tests of soil microbial activity. A novel synthetic amorphous Mn oxide (AMO), which was recently proposed as a stabilizing amendment, proved to be the most efficient in decreasing the mobility of the studied metals compared to nano-maghemite and nano-magnetite. Its application resulted in significant decreases of exchangeable metal fractions (92%, 92% and 93% decreases of Cd, Cu and Pb concentrations, respectively). The adsorption capacity of the AMO was an order of magnitude higher than those recorded for the other amendments. It was also the most efficient treatment for reducing Cu concentrations in the soil solution. No negative effects on soil microorganisms were recorded. On the other hand, the AMO was able to dissolve soil organic matter to some extent. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. 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.

  3. 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

  4. 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.

  5. CONTRIBUTIONS TO THE STUDY OF HEAVY METALS DISTRIBUTION (Zn, Pb, Cd, Bi, Cu IN SOME SOILS FROM GIURGEU MOUNTAINS

    Directory of Open Access Journals (Sweden)

    D. Bulgariu

    2005-10-01

    Full Text Available In this paper are presented the results of mineralogical and geochemical studies, realized for few soils from Giurgeu Mountains, which have as main purpose the distribution and mobility interpretation of minor elements (Cd, Cu, Pb, Zn, Bi in studied soil samples. The determination of fixed fractions and mobile fractions weight, at total contents of studied elements, and relative association of these elements with main mineral and organic components of soil samples, was realized on the basis of results obtained by sequential solid/ liquid extraction. The same, we try to use the correlation establish between metallic ions contents, as indicators of mineral paragenesis (the genetic type and formation conditions. The obtained results are agree with the results of similar studies from literature and they, underline of some interesting aspects about of distribution and migration of heavy metals in soils: (1 exist of some selectivity in heavy metals distribution in mineral components from soils, correlated with reciprocals geochemical affinities between speciation forms of metals and mineral components, in a given pedogeochemical context; (2 the heavy metals distribution between solid phases and soil solution are realized in competitive regime, and the inter-phases equilibrium evolution are thermodynamic and kinetics controlled by the solid/ liquid interfaces processes; (3 the fast elementary processes and local fluctuations of physic-chemical parameters are the main factors which controlled the inter-phases transfer ratio and the evolution direction of equilibriums of heavy metals distribution.

  6. 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.

  7. Distribution and speciation of metals (Cu, Zn, Cd, and Pb) in agricultural and non-agricultural soils near a stream upriver from the Pearl River, China.

    Science.gov (United States)

    Yang, Silin; Zhou, Dequn; Yu, Huayong; Wei, Rong; Pan, Bo

    2013-06-01

    The distribution and chemical speciation of typical metals (Cu, Zn, Cd and Pb) in agricultural and non-agricultural soils were investigated in the area of Nanpan River, upstream of the Pearl River. The investigated four metals showed higher concentrations in agricultural soils than in non-agricultural soils, and the site located in factory district contained metals much higher than the other sampling sites. These observations suggested that human activities, such as water irrigation, fertilizer and pesticide applications might have a major impact on the distribution of metals. Metal speciation analysis presented that Cu, Zn and Cd were dominated by the residual fraction, while Pb was dominated by the reducible fraction. Because of the low mobility of the metals in the investigated area, no remarkable difference could be observed between upstream and downstream separated by the factory site. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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

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    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.

  13. 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.

  14. 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.

  15. Effects of Crop Straw Returning with Lime on Activity of Cu, Zn, Pb and Cd in Paddy Soil

    Directory of Open Access Journals (Sweden)

    NI Zhong-ying

    2017-05-01

    Full Text Available Crop straw returning is an important measure for increasing soil carbon fixation and soil fertility in China, but it also may result in some risk of raising activity of heavy metals in the soil. In order to understand the effects of different sources of crop straw on heavy metals activity in soil with different pollution levels, and to take appropriate measures to prevent the activation of heavy metals in the soil, both pot and field experiments were carried out to study the effects of crop straw returning with lime on activity of Cu, Zn, Pb and Cd in paddy soil. The experiments were carried out in the soils with both light and heavy pollution of heavy metals. In the pot experiment, three straws, including rice straw with heavy pollution of heavy metals, rice straw with light pollution of heavy metals, and rape straw with light pollution of heavy metals, were tested. Two dosages of lime(0 kg·hm-2 and 750 kg·hm-2were applied. Field experiment had three treatments, ie., control without application of straw and lime, straw returning and straw returning + lime. Soil available heavy metals, accumulation of heavy metals in rice grain, and chemical forms of soil heavy metals were dynamical monitored. The results showed that crop straw returning increased significantly the concentrations of dissolved organic carbon and water soluble heavy metals in paddy soils at the early stage of experiment (in first 20 days. The increase in water soluble heavy metals in the soil with heavy pollution of heavy metals was most obvious as compared with the control treatment. After 60th day of the experiment, the effects of straw returning on the activity of heavy metals in the soil decreased gradually with the time, and became no obvious. The concentrations of water soluble heavy metals in the soil treated with rape straw was generally lower than that of rice straw, while those in the soil treated with heavy pollution of rice straw was higher than low pollution of rice

  16. 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. Copyright © 2011. Published by Elsevier Ltd.

  17. Effect of Na, Ca and pH on simultaneous uptake of Cd, Cu, Ni, Pb, and Zn in the water flea Daphnia magna measured using stable isotopes.

    Science.gov (United States)

    Komjarova, I; Blust, R

    2009-08-31

    The present study investigates the effects of Na(+), Ca(2+) and pH on the kinetics of Cd, Cu, Ni, Pb, and Zn uptake in Daphnia magna at low exposure concentrations measured using a stable isotope technique. Using experimental data the uptake rate constants were calculated for each metal individually on the basis of total metal concentrations. The copper uptake was not significantly affected by variations in chemical composition of the test medium. Calcium had a suppressing effect on the uptake of Cd, Ni, Pb and Zn. Specifically, Cd and Ni uptake rate constants decreased with increases in calcium concentrations from 0.1 to 2.5mM. The uptake of Zn and Pb was significantly suppressed only at 2.5mM Ca. The effect of sodium was less clear. There was no effect of varying sodium concentrations on the Ni uptake rate constants. Cd and Pb showed an increase in uptake rate constants at elevated sodium concentrations (2-8mM Na(+) for Cd and 8mM Na(+) for Pb). A bell-shaped response on increasing Na(+) concentrations was observed for Zn with a maximum value of uptake rate constant at the middle value (2mM Na(+)). Variation in pH of the medium affected Cd, Ni and Zn uptake processes. When Daphnia were exposed to acidic conditions (pH 6), the Cd and Ni uptake rate constants were the highest, while similarly low values were observed at neutral and basic conditions. In contrast, the uptake rates of Zn were linearly increasing with increasing pH of the medium.

  18. 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.

  19. 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.

  20. Distribution of Cd, Pb and Cu between dissolved fraction, inorganic particulate and phytoplankton in seawater of Terra Nova Bay (Ross Sea, Antarctica) during austral summer 2011-12.

    Science.gov (United States)

    Illuminati, S; Annibaldi, A; Romagnoli, T; Libani, G; Antonucci, M; Scarponi, G; Totti, C; Truzzi, C

    2017-10-01

    During the austral summer 2011-2012, the metal quotas of Cd, Pb and Cu in the phytoplankton of Terra Nova Bay (TNB, Antarctica) were measured for the first time. Evolution of all the three metal distributions between dissolved and particulate fractions during the season was also evaluated. Metal concentrations were mainly affected by the dynamic of the pack ice melting and phytoplankton activity. In mid-December when TNB area was covered by a thick pack ice layer and phytoplankton activity was very low, all the three metals were present mainly in their dissolved species. When the pack ice started to melt and the water column characteristics became ideal (i.e. moderate stratification, ice free area), the phytoplankton bloom occurred. Cd showed a nutrient-type behaviour with dissolved and particulate fractions mainly influenced by phytoplankton activity. Cd quota showed a mean value of 0.12 ± 0.07 nmol L(-1) (30-100% of the total particulate). Also Cu showed a nutrient-type behaviour, with its quota in phytoplankton varying between 0.08 and 2.1 nmol L(-1) (20-100% of the total particulate). Pb features the typical distribution of a scavenged element with very low algal content (0.03 ± 0.02 nmol L(-1), representing 20-50% of the total particulate). The vertical distribution of this element was influenced by several factors (e.g. pack ice melting, atmospheric inputs), the phytoplankton activity affecting Pb behaviour only partially. Metal:C ratios provide valuable information on the biological requirements for Cd, Pb and Cu, leading us to better understand their biogeochemical cycles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Distribution, mobility, and pollution assessment of Cd, Cu, Ni, Pb, Zn, and Fe in intertidal surface sediments of Sg. Puloh mangrove estuary, Malaysia.

    Science.gov (United States)

    Udechukwu, Bede Emeka; Ismail, Ahmad; Zulkifli, Syaizwan Zahmir; Omar, Hishamuddin

    2015-03-01

    Sungai Puloh mangrove estuary supports a large diversity of macrobenthic organisms and provides social benefits to the local community. Recently, it became a major recipient of heavy metals originating from industries in the hinterland as a result of industrialization and urbanization. This study was conducted to evaluate mobility and pollution status of heavy metals (Cd, Cu, Ni, Pb, Zn, and Fe) in intertidal surface sediments of this area. Surface sediment samples were collected based on four different anthropogenic sources. Metals concentrations were analyzed using an atomic absorption spectrophotometer (AAS). Results revealed that the mean concentrations were Zn (1023.68 ± 762.93 μg/g), Pb (78.8 ± 49.61 μg/g), Cu (46.89 ± 43.79 μg/g), Ni (35.54 ± 10.75 μg/g), Cd (0.94 ± 0.29 μg/g), and Fe (7.14 ± 0.94%). Most of the mean values of analyzed metals were below both the interim sediment quality guidelines (ISQG-low and ISQG-high), except for Pb concentration (above ISQG-low) and Zn concentration (above ISQG-high), thus suggesting that Pb and Zn may pose some environmental concern. Cadmium, Pb, and Zn concentrations were above the threshold effect level (TEL), indicating seldom adverse effect of these metals on macrobenthic organisms. Pollution load index (PLI) indicated deterioration and other indices revealed the intertidal surface sediment is moderately polluted with Cd, Pb, and Zn. Therefore, this mangrove area requires urgent attention to mitigate further contamination. Finally, this study will contribute to data sources for Malaysia in establishing her own ISQG since it is a baseline study with detailed contamination assessment indices for surface sediment of intertidal mangrove area.

  2. 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.

  3. 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.)

  4. 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.

  5. Children's health risk assessment based on the content of toxic metals Pb, Cd, Cu and Zn in urban soil samples of Podgorica, Montenegro.

    Science.gov (United States)

    Mugoša, Boban; Djurović, Dijana; Pirnat, Aleksandra; Bulat, Zorica; Barjaktarović-Labović, Snežana

    2015-09-01

    Due to their low tolerance to pollutants and hand-to-mouth pathways the health risk is very high in children's population. The aim of this study was to evaluate risk to children's health based on the content of heavy metals in urban soil samples from Podgorica, Montenegro. This study included the investigation of several toxic metals such as Pb, Cd, Cu and Zn in soil samples from public parks and playgrounds. Sampling was conducted in a period October-November, 2012. Based on cluster analysis, soil samples were divided into two groups related to similarity of metal content at examinated locations: the group I--near by recreational or residential areas of the city, and the group II--near traffic roads. Concentration of toxic metals, in urban soil samples were determined by a graphite furnace atomic absorption spectrometry (Pb and Cd) and by inductively coupled plasma optical emission spectrometry technique after microwave digestion. Due to exposure to urban soil, non-cancerogenic index hazardous index (HI) for children was estimated using 95th percentile values of total metal concentration. The value of the total (ingestion, dermal and inhalation) HI is calculated for maximum, minimum and the average concentration of metals for children. Mean concentrations of Pb, Cd, Cu and Zn in the surface layer of the studied urban soils were 85.91 mg/kg, 2.8 mg/kg and 52.9 mg/kg and 112.5 mg/kg, respectively. Samples from group II showed higher metal content compared to group I. Urbanization and traffic are the main sources of pollution of the urban soils of Podgorica. Most of the samples (93.5%) had a high Pb content, 12.9% of the samples had a higher content of Cd, while Cu and Zn were within the limits prescribed by national legislation. At one location the level of security for lead is HI = 0.8 and very closed to maximum acceptable value of 1. It is probably the result of intensive traffic near by. All metals investigated showed relatively higher concentrations at sites

  6. 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.

  7. 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

  8. 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。

  9. Phytoremediation of Cd, Cr, Cu, Mn, Fe, Ni, Pb and Zn from aqueous solution using Phragmites cummunis, Typha angustifolia and Cyperus esculentus.

    Science.gov (United States)

    Chandra, Ram; Yadav, Sangeeta

    2011-07-01

    A comparative bioaccumulation pattern and ultra structural changes were studied in Phragmites cummunis, Typha angustifolia and Cyperus esculentus in mixed metals solution of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn). P. cummunis was observed to be a shoot accumulator for Cr, Fe, Mn, Ni, Pb, and Zn. However, T. angustifolia was found to be a root accumulator for Cd, Cr, Cu, Fe, Ni and Pb. In addition, C. esculentus also accumulated most of the tested heavy metals in the roots, while Mn and Fe were translocated up to leaves. Further, the long term metal treatment showed maximum accumulation of all heavy metals in P. cummunis followed by T. angustifolia and C. esculentus. Among heavy metals, Fe was accumulated maximum, i.e., >1000 microg g(-1) by all three plants. Simultaneously, the adverse effects on biochemical parameters were noted earlier in C. esculentus than T. angustifolia and P. cummunis. Ultra structural observation showed the cellular changes in wetland plants after longer exposure. Results revealed that P. cummunis and T. angustifolia had more potential for tested metals than C. esculentus. This study established that these wetland plants could be used for heavy metals phytoremediation from metal containing industrial wastewater.

  10. 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).

  11. 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.

  12. 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).

  13. 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.

  14. Drinking water interlaboratory ring test. Part IV. Results of some cationic analytes. Al, Zn, Cd, Cr, Pb, Ni, Mn, Fe, Cu and V; Circuito interlaboratorio Unichim sulle acque potabili. Parte IV. Risultati di alcuni cationi metallici. Al, Zn, Cd, Co, Cr, Pb, Ni, Mn, Fe, Cu e V

    Energy Technology Data Exchange (ETDEWEB)

    Cavaterra, E.; Divo, C.; Bottazzini, N. [Unichim, Milan (Italy); Alava, F. [Bergamo Ambiente e Servizi, Bergamo (Italy); Bettinelli, M. [Electric Power Production Company, Piacenza (Italy); Bonfiglioli, F. [Azienda Mediterranea Gas e Acqua SpA, Genoa (Italy)

    2002-01-01

    In this paper results of statistical treatment of experimental data obtained in some cycles of an interlaboratory ring test of content of Al, Zn, Cd, Co, Cr, Pb, Ni, Mn, Fe, Cu and V in drinking water are reported. Means, variances and parameters of precision and accuracy of some analytical techniques and methods employed by laboratories participating to the ring test will be reported and discussed. [Italian] Nel presente lavoro vengono riportati i risultati dell'elaborazione statistica dei dati sperimentali ottenuti in alcuni cicli del circuito interlaboratorio e relativi ai seguenti cationi metallici: Al, Zn, Cd, Co, Cr, Pb, Ni, Mn, Fe, Cu e V. Vengono riportati e discussi i valori medi e la varianza ed infine i dati di accuratezza e precisione delle tecniche o metodi d'analisi impiegati dai laboratori partecipanti al circuito.

  15. Metales traza (Cu, Zn, Cd y Pb) en peces juveniles de las guarderías estuáricas a lo largo de la costa portuguesa

    OpenAIRE

    Rita P. Vasconcelos; Reis-Santos, Patrick; Maia, Anabela; Ruano, Miguel; Costa, Maria J.; Cabral, Henrique N.

    2011-01-01

    La contaminación orgánica e inorgánica puede afectar a los organismos, a saber al estado fisiológico, crecimiento y supervivencia de los peces juveniles los cuales utilizan los estuarios como guarderías; afectando de forma cuantitativa y cualitativa a la poblaciones marinas adultas. La contaminación de elementos traza (Cu, Zn, Cd, Pb) en las formas juveniles de los peces comerciales Solea solea, Solea senegalensis, Platichthys flesus, Diplodus vulgaris y Dicentrarchus labrax recolectados en g...

  16. [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.

  17. 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.

  18. 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.

  19. 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.

  20. 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+.

  1. 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.

  2. An investigation of toxic heavy metals (Pb, Cd, Cu, Cr and Zn in Garlic (Allium sativum L. and soil samples collected from different locations of Punjab, Pakistan using atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Sadia Ata

    2014-07-01

    Full Text Available The present study is based on the determination of heavy metal contents (Pb, Cd, Cu, Cr and Zn in garlic and soil samples collected from ten different locations of Punjab, Pakistan using flame atomic absorption spectrometer. In garlic samples, Pb, Cd, Zn, Cu and Cr ranged from 4.9 to 94.6 mg/kg, 0.625 to 151.4 mg/kg, 3.7 to 56.4 mg/kg, 2.5 to 50.2mg/kg and 56.4 to 111.6 mg/kg respectively, whereas Pb, Cd, Cr, Zn and Cu in investigated soil samples ranged respectively from 57.4 to 99.6 mg/kg, 25.6 to 132.7 mg/kg, 61.7 to 115.1 mg/kg, 9.2 to 324.7 mg/kg and 15.5 to 34.5 mg/kg. Elevated concentration of Pb and Cd was found in garlic samples from Gujranwala, Cr concentration was found to be higher in samples collected from Raiwind while the other metals such as Cu and Zn were predominant in samples from Kasur. Heavy metal content in soil and garlic samples was within the permissible limits proposed by World Health Organization (WHO except Cd, Cr and Zn which showed elevated levels in almost all soil and garlic samples. Average concentrations determined in all samples represented that metal content in soil samples was in increasing order as Zn<CuCu

  3. Direct Method for Determination of Al, Cd, Cu, and Pb in Beers In Situ Digested by GF AAS Using Permanent Modifiers.

    Science.gov (United States)

    de Oliveira Borges, Simone Soares; Beinner, Mark Anthony; Silva, José Bento Borba

    2015-09-01

    The object of the present study was to development of safe, reliable fast, and efficient methodologies for the direct determination of Al, Pb, Cu, and Cd in non-digested beer samples of widely consumed brand name beers sold in Brazil, using graphite furnace absorption spectrometry (GF AAS). Pyrolysis and atomization temperature curves of selected chemical modifiers (iridium, rhodium, ruthenium, zirconium, and non-modifier use) were used to stabilize each metal and sensitivity in a beer sample was diluted to 1:1 with 0.2 % v/v nitric acid after degasification. The best modifier for aluminum was permanent zirconium, with a characteristic mass of 4.2 pg (recommended is 10 pg), demonstrating a symmetrical peak with a corrected background using a deuterium arc lamp. For cadmium and copper, the best modifier was permanent ruthenium with characteristic masses of 0.3 and 7 pg (recommended are 0.35 and 4 pg, respectively, for Cd and Cu), respectively. The best condition for lead was using a non-modifier, with a characteristic mass of 6.9 pg (recommended is 10 pg). The limits of detection and mean recoveries, done over three consecutive days for aluminum, copper, lead, and cadmium, were 1.9, 2.9, 0.8, and 0.6 pg and 105, 104, 101, and 102 %, respectively. From the observed results, we may conclude that some metals, such as Al, Cd, Cu, and Pb, can be determined easily with graphite furnace atomic absorption spectrometry without sample digestion using a dilute nitric acid solution.

  4. 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

  5. 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.

  6. 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

  7. Automated preconcentration of Fe, Zn, Cu, Ni, Cd, Pb, Co, and Mn in seawater with analysis using high-resolution sector field inductively-coupled plasma mass spectrometry.

    Science.gov (United States)

    Rapp, Insa; Schlosser, Christian; Rusiecka, Dagmara; Gledhill, Martha; Achterberg, Eric P

    2017-07-11

    A rapid, automated, high-throughput analytical method capable of simultaneous analysis of multiple elements at trace and ultratrace levels is required to investigate the biogeochemical cycle of trace metals in the ocean. Here we present an analytical approach which uses a commercially available automated preconcentration device (SeaFAST) with accurate volume loading and in-line pH buffering of the sample prior to loading onto a chelating resin (WAKO) and subsequent simultaneous analysis of iron (Fe), zinc (Zn), copper (Cu), nickel (Ni), cadmium (Cd), lead (Pb), cobalt (Co) and manganese (Mn) by high-resolution inductively-coupled plasma mass spectrometry (HR-ICP-MS). Quantification of sample concentration was undertaken using isotope dilution for Fe, Zn, Cu, Ni, Cd and Pb, and standard addition for Co and Mn. The chelating resin is shown to have a high affinity for all analyzed elements, with recoveries between 83 and 100% for all elements, except Mn (60%) and Ni (48%), and showed higher recoveries for Ni, Cd, Pb, Co and Mn in direct comparison to an alternative resin (NOBIAS Chelate-PA1). The reduced recoveries for Ni and Mn using the WAKO resin did not affect the quantification accuracy. A relatively constant retention efficiency on the resin over a broad pH range (pH 5-8) was observed for the trace metals, except for Mn. Mn quantification using standard addition required accurate sample pH adjustment with optimal recoveries at pH 7.5 ± 0.3. UV digestion was necessary to increase recovery of Co and Cu in seawater by 15.6% and 11.4%, respectively, and achieved full break-down of spiked Co-containing vitamin B12 complexes. Low blank levels and detection limits could be achieved (e.g., 0.029 nmol L(-1) for Fe and 0.028 nmol L(-1) for Zn) with the use of high purity reagents. Precision and accuracy were assessed using SAFe S, D1, and D2 reference seawaters, and results were in good agreement with available consensus values. The presented method is ideal for

  8. 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

  9. Seasonal variation of Zn, Pb, Cu and Cd concentrations in the root-sediment system of Spartina maritima and Halimione portulacoides from Tagus estuary salt marshes.

    Science.gov (United States)

    Caçador, I; Vale, C; Catarino, F

    2000-04-01

    Concentrations of Zn, Pb, Cu and Cd have been determined in leaves, stems and roots of Spartina maritima and Halimione portulacoides from the Tagus estuary salt mash (Corroios) and in the sediments between their roots. Biological materials and sediments were sampled every 2 months, between July 1991 and July 1992. Root biomass increased from July to September and from January to March. The greatest metal concentrations occurred in the roots, with lowest levels in January and increasing levels during the growth periods. Zn, Pb and Cu in sediments exhibited a corresponding change in concentrations, reaching maximum in January and subsequently decreasing in spring. The ratios between metal concentrations in the root and in sediments were higher for H. portulacoides when compared to S. maritima, whose roots are surrounded by a more acidic and reduced sediment environment. It was concluded, therefore, that H. portulacoides is a more effective accumulator of metals than S. maritima, and both root-sediment systems exhibited a seasonal variation of metal concentrations.

  10. Spatial and Temporal Distribution of Trace Metals (Cd, Cu, Ni, Pb, and Zn in Coastal Waters off the West Coast of Taiwan

    Directory of Open Access Journals (Sweden)

    Kuo-Tung Jiann

    2014-01-01

    Full Text Available Surface water samples were collected along the west coast of Taiwan during two expedition cruises which represent periods of different regional climatic patterns. Information on hydrochemical parameters such as salinity, nutrients, suspended particulate matter (SPM, and Chlorophyll a concentrations were obtained, and dissolved and particulate trace metal (Cd, Cu, Ni, Pb, and Zn concentrations were determined. Spatial variations were observed and the differences were attributed to (1 influence of varying extents of terrestrial inputs from the mountainous rivers of Taiwan to the coast, and (2 urbanization and industrialization in different parts of the island. Geochemical processes such as desorption (Cd and adsorption to sinking particles (Pb also contributed to the variability of trace metal distributions in coastal waters. Results showed temporal variations in chemical characteristics in coastal waters as a consequence of prevailing monsoons. During the wet season when river discharges were higher, the transport of particulate metals was elevated due to increased sediment loads. During the dry season, lower river discharges resulted in a lesser extent of estuarine dilution effect for chemicals of anthropogenic sources, indicated by higher dissolved concentrations present in coastal waters associated with slightly higher salinity.

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

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    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.

  12. 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.

  13. 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.

  14. 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 +.

  15. 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.

  16. 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.

  17. Origen y comportamiento de Cd, Cr, Cu, Pb y Zn en el subsistema acuífero de la Plana de Castellón

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    Morell, I.

    1996-12-01

    Full Text Available A study on Cd, Cr, Cu, Pb and Zn concentrations in Castellón Plain aquifer has been carried out in order to know if the industrial activity of this zone affects to the groundwater quality. Adsorption processes and relative migration velocity of these metals through the soils of this zone have also been studied. Metal concentrations in the aquifer are lower than those expected in an area with an intense industrial activity. It can be due to the fact that these metals show high adsorption coefficients in the soils and very low migration velocities through them, so it is no probable that the metals from the waste-waters reach the aquifer, or they take some time to reach it.En el presente trabajo se estudia la concentración de Cd, Cr, Cu, Pb y Zn en el acuífero de la Plana de Castellón, para conocer si la actividad industrial de la zona afecta a la calidad de las aguas subterráneas. Asimismo se estudian los procesos de adsorción y velocidad de migración de dichos metales en suelos de la zona. Las concentraciones de metales en el acuífero son más bajas de lo que cabría esperar, dada la intensa actividad industrial de la zona. Ello puede ser debido a que, dado que los metales presentan altos coeficientes de adsorción en los suelos y una velocidad de migración a través de los mismos muy reducida, no parece probable que dichos elementos procedentes de vertidos de aguas residuales lleguen a alcanzar el acuífero, o, en todo caso, tardarán muchos años en hacerlo, ya que el suelo actúa reteniéndolos y retrasando su llegada al mismo.

  18. Sol-gel zirconia coating capillary microextraction on-line hyphenated with inductively coupled plasma mass spectrometry for the determination of Cr, Cu, Cd and Pb in biological samples.

    Science.gov (United States)

    Wu, Yiwei; Hu, Bin; Jiang, Zucheng; Feng, Yuqi; Lu, Peng; Li, Boyangzi

    2006-01-01

    A sol-gel zirconia coating was developed for the preconcentration/separation of trace Cr, Cu, Cd and Pb by capillary microextraction, and the adsorbed analytes were on-line eluted for detection using inductively coupled plasma mass spectrometry (ICP-MS). By immobilizing sol-gel zirconia on the inner surface of a fused-silica capillary, the sol-gel zirconia coating was simply prepared. Its adsorption properties, stability and the factors affecting the adsorption behaviors of Cr, Cu, Cd and Pb were investigated in detail. In the pH range from 7.8 to 10, the zirconia-coated capillary (35 cm x 0.15 mm) is selective towards Cr, Cu, Cd and Pb, and the analyzed ions could be desorbed quantitatively with 0.2 mL of 0.5 mol/L HNO(3) at a rate of 0.2 mL/min. With a consumption of 1.25 mL sample solution, an enrichment factor of 6.25, and detection limits (3sigma) of 9.9 pg/mL Cr, 17.9 pg/mL Cu, 4.5 pg/mL Cd and 3.7 pg/mL Pb were obtained. The precisions for nine replicate measurements of 1 ng/mL Cr, Cu, Cd and Pb were 4.9% Cr, 2.2% Cu, 2.0% Cd and 3.2% Pb (RSD), respectively. The proposed procedure has been applied to the determination of Cr, Cu, Cd and Pb in human urine, which was subjected to microwave-assisted digestion prior to analysis, and the recoveries for these elements were 89.2-101.8%. In order to validate the developed procedure, a NIES No.10-a Rice Flour-Unpolished certified reference material and a BCR No. 184 Bovine Muscle certified reference material were analyzed, and the results are in good agreement with the certified values. Copyright (c) 2006 John Wiley & Sons, Ltd.

  19. 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

  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. 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.

  2. 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.

  3. Forest Soil Pollution with Heavy Metals (Pb, Zn, Cd, and Cu in the Area of the “French Mines” on the Medvednica Mountain, Republic of Croatia

    Directory of Open Access Journals (Sweden)

    Ivan Perković

    2017-01-01

    Full Text Available Background and Purpose: This paper deals with the results of the investigation of the selected heavy metal contents in forest soil in the region of an abandoned mine. The analysis of the forest ecosystem soil on the Medvednica Mountain was conducted in the region of the so-called “French Mines” (FM. The elements selected for analyses were cadmium (Cd, copper (Cu, lead (Pb, and zinc (Zn because of their toxicological characteristics. Material and Methods: In the investigated area - five entrances of the FM - composite topsoil samples (0–5 cm were taken. Those samples were compared to the control samples which were taken outside the area affected by mines. The soil samples were analysed for the following parameters: pH, particle size distribution, organic C content and pseudo-total mass fractions of the selected heavy metals. The heavy metals were determined by atomic emission spectrometry with inductively coupled plasma (ICP-MS. Results and Conclusion: The results reveal that the soil is locally polluted, i.e. the highest mass fraction values of these four heavy metals were found in the area of the FM. Average pseudo-total fraction of Cd in the analysed topsoil samples was in the range of 0.17–4.41 mg·kg−1 (median: 0.97 mg·kg−1. Cu was found in the range of 4.54–1260 mg·kg−1 (median: 45.7 mg·kg−1. In the case of Zn, mass fraction values were found in the range of 36.8–865 mg·kg−1 (median: 137 mg·kg−1. Finally, average values of the pseudo-total fraction of Pb were found in the range of 58.4–12000 mg·kg−1 (median: 238 mg·kg−1. The results reveal that mining activities leave consequences on soil for a long time.

  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. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. The Adsorption of Pb, Zn, Cu, Ni, and Cd by Modified Ligand in a Single Component Aqueous Solution: Equilibrium, Kinetic, Thermodynamic, and Desorption Studies

    Directory of Open Access Journals (Sweden)

    E. Igberase

    2017-01-01

    Full Text Available In this investigation, an amino functionalized adsorbent was developed by grafting 4-aminobenzoic acid onto the backbone of cross-linked chitosan beads. The 3 sets of beads including chitosan (CX, glutaraldehyde cross-linked chitosan (CCX, and 4-aminobenzoic acid grafted cross-linked chitosan (FGCX were characterized by FTIR, XRD, SEM, and TGA. The water content and amine concentration of FGCX were determined. The effect of adsorption parameters was studied and the optimum was used for further studies. Equilibrium data was obtained from the adsorption experiment carried out at different initial concentration; the data were applied in isotherm, thermodynamics, and kinetic studies. The Langmuir and Dubinin-Kaganer-Radushkevich (DKR models were successful in describing the isotherm data for the considered metal ions while the Freundlich and Temkin model fit some of the considered metal ions. Pseudo-second-order and intraparticle model described the kinetic data quite well. Thermodynamic parameters such as Gibb’s free energy change (ΔGo, enthalpy change (ΔHo, and entropy change (ΔSo were calculated and the results showed that the adsorption of Pb, Cu, Ni, Zn, and Cd ions onto FGCX is spontaneous and endothermic in nature. Regeneration of the spent adsorbent was efficient for the considered metal ions.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Determination of uranium isotopes ({sup 235}U, {sup 238}U) and trace elements (Cd, Pb, Cu and As) in bottled drinking water by Icp-SFMS; Determinacion de isotopos de uranio ({sup 235}U, {sup 238}U) y elementos traza (Cd, Pb, Cu y As) en agua embotellada para beber por ICP-SFMS

    Energy Technology Data Exchange (ETDEWEB)

    Lara A, N.; Hernandez M, H.; Romero G, E. T.; Kuri de la C, A.; Perez B, M. A., E-mail: nancy.lara@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2016-09-15

    In the present work we propose an optimized method for the quantification of uranium isotopes ({sup 235}U, 2{sup 38}U) and the elements Cd, Pb, Cu and As in bottled water for drinking at trace levels of concentration. Based on the multi-element detection capability, the high sensitivity and resolution that the Mass Spectrometry with Magnetic Sector with Inductively Coupled Plasma Source (Icp-SFMS) technique offers; the high, medium and low resolution analysis conditions for the elements under study were established and optimized using and Element 2/Xr equipment and the 23 multi-elemental Certified Reference Material (CRM). The analysis method was validated using the standard reference material Nist 1643d and CRM mono-elemental s as external standards for the quantification of the analytes. Samples, targets and CRM were acidified with 2% of HNO{sub 3} and analyzed without pretreatment under the established analysis conditions. The results obtained show concentrations of {sup 235}U, {sup 238}U, {sup 111}Cd, {sup 208}Pb, {sup 63}Cu and {sup 75}As in the range of μg L{sup -1}, the linearity obtained from the calibration curves for each element has correlation coefficients < 0.99 in all cases, the accuracy of the method in terms of percent relative standard deviation (RSD %) was less than 5%, the mean recovery rate of Nist 1643d ranged from 96.46% to 101.12%. The optimization of the method guarantees the stability and calibration of the equipment throughout the analysis, as well as the ability to resolve interferences. In conclusion, the method proposed using Icp-SFMS offers the advantages of being fast and simple for the multi-elemental analysis in water at trace levels, with low limits of quantification and detection, with good linearity, accuracy, precision and reproducibility to a degree of reliability of 95%. (Author)

  17. 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

  18. 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

  19. 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...

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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...

  8. 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。

  9. 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.)

  10. 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.

  11. 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.

  12. 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...

  13. 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.

  14. 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.

  15. 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%.

  16. Measurement of p-nitrophenyl acetate esterase activity (EA), total antioxidant capacity (TAC), total oxidant status (TOS) and acetylcholinesterase (AChE) in gills and digestive gland of Mytilus galloprovincialis exposed to binary mixtures of Pb, Cd and Cu.

    Science.gov (United States)

    Franco-Martinez, Lorena; Romero, Diego; García-Navarro, José A; Tecles, Fernando; Teles, Mariana; Tvarijonaviciute, Asta

    2016-12-01

    The aims of the present work were (1) to evaluate oxidative stress biomarkers and AChE in two tissues of wild mussel (Mytilus galloprovincialis) of high biochemical activity and accumulation capacity (gills and digestive gland) and (2) to study the behaviour of these biomarkers in presence of heavy metals. For this, EA, TOS, TAC and AChE were measured in tissues of mussels exposed to binary combination of Pb, Cd and Cu. Mussels (n = 36) were exposed to one of the binary mixtures of Pb (1000 μg L(-1)), Cd (100 μg L(-1)) and Cu (100 μg L(-1)) for 7 days, under controlled conditions. Gills and digestive gland were extracted and frozen at -80 °C until analysis. The automatic methods employed for the measurement of EA, TAC, TOS and AChE in M. galloprovincialis revealed higher levels of these biomarkers in digestive gland than gills. Study results suggest that gills would be the tissue of election for study oxidative stress markers, whereas digestive tissue should be selected for AChE measurements in case of evaluation of combined metal toxicity in mussels.

  17. 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.

  18. 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.

  19. 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.

  20. Chemometric evaluation of Cd, Co, Cr, Cu, Ni (inductively coupled plasma optical emission spectrometry) and Pb (graphite furnace atomic absorption spectrometry) concentrations in lipstick samples intended to be used by adults and children.

    Science.gov (United States)

    Batista, Érica Ferreira; Augusto, Amanda dos Santos; Pereira-Filho, Edenir Rodrigues

    2016-04-01

    A method was developed for determining the concentrations of Cd, Co, Cr, Cu, Ni and Pb in lipstick samples intended to be used by adults and children using inductively coupled plasma optical emission spectrometry (ICP OES) and graphite furnace atomic absorption spectrometry (GF AAS) after treatment with dilute HNO3 and hot block. The combination of fractional factorial design and Desirability function was used to evaluate the ICP OES operational parameters and the regression models using Central Composite and Doehlert designs were calculated to stablish the best working condition for all analytes. Seventeen lipstick samples manufactured in different countries with different colors and brands were analyzed. Some samples contained high concentrations of toxic elements, such as Cr and Pb, which are carcinogenic and cause allergic and eczematous dermatitis. The maximum concentration detected was higher than the permissible safe limits for human use, and the samples containing these high metal concentrations were intended for use by children. Principal component analysis (PCA) was used as a chemometrics tool for exploratory analysis to observe the similarities between samples relative to the metal concentrations (a correlation between Cd and Pb was observed). Copyright © 2015 Elsevier B.V. All rights reserved.

  1. 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

  2. Approach to spatialize local to long-range atmospheric metal input (Cd, Cu, Hg, Pb) in epiphytic lichens over a meso-scale area (Pyrénées-Atlantiques, southwestern France).

    Science.gov (United States)

    Barre, Julien P G; Deletraz, Gaëlle; Frayret, Jérôme; Pinaly, Hervé; Donard, Olivier F X; Amouroux, David

    2015-06-01

    Geographically based investigations into atmospheric bio-monitoring usually provide information on concentration or occurrence data and spatial trends of specific contaminants over a specified study area. In this work, an original approach based on geographic information system (GIS) was used to establish metal contents (Hg, Cu, Pb, and Cd) in epiphytic lichens from 90 locations as atmospheric bio-monitors over a meso-scale area (Pyrénées-Atlantiques, southwestern France). This approach allows the integration of the heterogeneity of the territory and optimization of the sampling sites based on both socioeconomical and geophysical parameters (hereafter defined as urban, industrial, agricultural, and forested areas). The sampling strategy was first evaluated in several sites (n = 15) over different seasons and years in order to follow the temporal variability of the atmospheric metal input in lichens. The results demonstrate that concentration ranges remain constant over different sampling periods in "rural" areas (agricultural and forested). Higher variability is observed in the "anthropized" urban and industrial areas in relation to local atmospheric inputs. In this context, metal concentrations in lichens over the whole study show that (1) Hg and Cd are homogeneous over the whole territory (0.14 ± 0.04 and 0.38 ± 0.26 mg/kg, respectively), whereas (2) Cu and Pb are more concentrated in "anthropized" areas (9.3 and 11.9 mg/kg, respectively) than in "rural" ones (6.8 and 6.0 mg/kg, respectively) (Kruskall-Wallis, K(Cu) = 13.7 and K(Pb) = 9.7, p < 0.00001). They also showed a significant local enrichment for all metals in many locations in the Pays Basque (West) mainly due to metal and steel industrial activities. This confirms the local contribution of this contamination source over a wider geographic scale. A multiple linear regression model was applied to give an integrated spatialization of the data. This showed significant

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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%.

  8. 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...

  9. 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% .

  10. Chemical speciation of Pb(II, Cd(II, Hg(II, Co(II, Ni(II, Cu(II and Zn(II binary complexes of l-methionine in 1,2-propanediol-water mixtures

    Directory of Open Access Journals (Sweden)

    M. Padma Latha

    2007-04-01

    Full Text Available Chemical speciation of Pb(II, Cd(II, Hg(II, Co(II, Ni(II, Cu(II and Zn(II complexes of L-methionine in 0.0-60 % v/v 1,2-propanediol-water mixtures maintaining an ionic strength of 0.16 M at 303 K has been studied pH metrically. The active forms of ligand are LH2+, LH and L-. The predominant species detected are ML, MLH, ML2, ML2H, ML2H2 and MLOH. Models containing different numbers of species were refined by using the computer program MINIQUAD 75. The best-fit chemical models were arrived at based on statistical parameters. The trend in variation of complex stability constants with change in the dielectric constant of the medium is explained on the basis of electrostatic and non-electrostatic forces.

  11. 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.

  12. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yahya, Nabil A.A. [Thamar University, Physics Department, Faculty of Education, Thamar (Yemen); Al-Gaashani, R. [Thamar University, Physics Department, Faculty of Education, Thamar (Yemen); Qatar Environment and Energy Research Institute (QEERI), Hamad Bin Khalifa University (HBKU), Doha (Qatar); Abd-Shukor, R. [Universiti Kebangsaan Malaysia, School of Applied Physics, Bangi, Selangor (Malaysia)

    2017-03-15

    A PbO-CdO nanocomposite-added Bi{sub 1.6}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} ((Bi,Pb)-2223) superconductor has been prepared. The effect of the PbO-CdO nanocomposite addition on the transport critical current density (J{sub c}) of (Bi,Pb)-2223 superconductor was investigated. The transition temperature (T{sub c-onset}), zero electrical resistance temperature (T{sub c-R=0}), and J{sub 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{sub c} phase (Bi-2223) compared to the non-added sample. A slight increase in T{sub c-R=0} of x = 0.15 wt% was observed. J{sub 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{sub c} of x = 0.15 wt% added sample was more than 20 times larger than J{sub c} of the non-added sample (x = 0 wt%). A combined effect of enhanced flux pinning, increased fraction of high-T{sub c} phase and improved grain size, which led to increase in the J{sub c} of added samples, is discussed. (orig.)

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. EXPLORING POSSIBILITIES OF CULTIVATION A UNPOLLUTED PLANT PRODUCE IN Pb AND Cd CONTAMINATED SITES

    Directory of Open Access Journals (Sweden)

    Atanas TOMOV

    2006-02-01

    Full Text Available The control of heavy metals in such way that soil function and product quality are not impeded is a prerequisite to sustainable agriculture. Growing anthropogenic fl uxes of toxic heavy metals in agro-ecosystems affect on purity of farm products and soil fertility. In the article we describe a fi eld experiment – cultivation of potatoes on soil with a medium level of pollution / Zn, Cu, Pb, Cd etc/. We studied the most toxic of them – Pb and Cd; as well as the possibilities for reducing their phytoavailability and accumulation in potatoes tubers, applying soil amendments.

  4. 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.

  5. Use of limestone filler as a sorbent for the removal of As(V), Pb(II), Cu(II), Zn(II) and Cd(II) in contaminated sites

    Science.gov (United States)

    Martinez Sanchez, Maria Jose; Veiga, Jose Manuel; Garcia-Lorenzo, Maria Luz; Hernandez Cordoba, Manuel; Martinez-Lopez, Salvadora; Perez-Sirvent, Carmen

    2017-04-01

    Many of the approaches used to treat soils contaminated by heavy metals are invasive, and do not restore the natural equilibrium of the environment [1]. For this reason, one of procedures used to stabilise heavy metal-contaminated soils in situ is to directly add amendments, which, while they may not totally eliminate toxic elements, help natural retention mechanisms, induce sorption and reduce mobility and bioavailability. In this respect, the use of calcareous materials may be an excellent, eco-friendly way for recovering this type of soils [2], and this communication reports studies made in our laboratory for such a purpose. The influence of different variables in the preparation of mixtures used to stabilize contaminated soils (soil pH, temperature and composition of the contaminated soil / limestone filler) was studied by means of a factorial experimental design. The main interaction effects of the factors obtained on different contaminated soils were used along with the results of the physicochemical and mineralogical characterization in the same data matrix to be analyzed by principal components analysis (PCA). To evaluate the optimal values of the variables, spectroscopic techniques were used to measure the level of leached metals (Pb, Cd, Cu, As, Zn and Fe). The environmental conditions were simulated and controlled by means of a climatic chamber to evaluate simultaneously the processes of geochemical alteration and passivation of the mixture. The results obtained showed that the corresponding factors of the experimental design may be an important source of information to show correlations on some of the most significant variables such as the concentration of metals and, in this way, optimize the use of the in situ stabilizer. [1] H. Genç-Fuhrman, P.S. Mikkelsen, A. Ledin. Water Res 41 (2007) 591-602. [2] C. A. Cravotta, M.K. Trahan. Appl. Geochem 5 (1999) 581-606.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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%.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. (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.

  4. 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.}

  5. New roles for icosahedral clusters in intermetallic phases: micelle-like segregation of Ca-Cd and Cu-Cd interactions in Ca10Cd27Cu2.

    Science.gov (United States)

    Hadler, Amelia B; Harris, Nicholas A; Fredrickson, Daniel C

    2013-11-20

    Despite significant progress in the structural characterization of the quasicrystalline state, the chemical origins of long- and short-range icosahedral order remain mysterious and a subject of debate. In this Article, we present the crystal structure of a new complex intermetallic phase, Ca10Cd27Cu2 (mC234.24), whose geometrical features offer clues to the driving forces underlying the icosahedral clusters that occur in Bergman-type quasicrystals. Ca10Cd27Cu2 adopts a C-centered monoclinic superstructure of the 1/1 Bergman approximant structure, in which [110] layers of Bergman clusters in the 1/1 structure are separated through the insertion of additional atoms (accompanied by substantial positional disorder). An examination of the coordination environments of Ca and Cu (in the ordered regions) reveals that the structure can be viewed as a combination of coordination polyhedra present in the nearest binary phases in the Ca-Cd-Cu compositional space. A notable feature is the separation of Ca-Cd and Cu-Cd interactions, with Bergman clusters emerging as Ca-Cd Friauf polyhedra (derived from the MgZn2-type CaCd2 phase) encapsulate a Cu-Cd icosahedron similar to those appearing in Cu2Cd5. DFT chemical pressure calculations on nearby binary phases point to the importance of this segregation of Ca-Cd and Cu-Cd interactions. The mismatch in atomic size between Cu and Cd leads to an inability to satisfy Ca-Cu and Ca-Cd interactions simultaneously in the Friauf polyhedra of the nearby Laves phase CaCd2. The relegation of the Cu atoms to icosahedra prevents this frustration while nucleating the formation of Bergman clusters.

  6. 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.

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

    Science.gov (United States)

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

    2015-01-01

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

  8. 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.

  9. 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.

  10. 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.

  11. Lead (Pb) and copper (Cu) share a common uptake transporter in the unicellular alga Chlamydomonas reinhardtii.

    Science.gov (United States)

    Sánchez-Marín, Paula; Fortin, Claude; Campbell, Peter G C

    2014-02-01

    The unicellular alga Chlamydomonas reinhardtii has a very high rate of lead (Pb) internalization and is known to be highly sensitive to dissolved Pb. However, the transport pathway that this metal uses to cross cellular membranes in microalgae is still unknown. To identify the Pb(2+) transport pathway in C. reinhartdii, we performed several competition experiments with environmentally relevant concentrations of Pb(2+) (~10 nM) and a variety of divalent cations. Among the essential trace metals tested, cobalt, manganese, nickel and zinc had no effect on Pb internalization. A greater than tenfold increase in the concentrations of the major ions calcium and magnesium led to a slight decrease (~34 %) in short-term Pb internalization by the algae. Copper (Cu) was even more effective: at a Cu concentration 50 times higher than that of Pb, Pb internalization by the algae decreased by 87 %. Pre-exposure of the algae to Cu showed that the effect was not due to a physiological effect of Cu on the algae, but rather to competition for the same transporter. A reciprocal effect of Pb on Cu internalization was also observed. These results suggest that Cu and Pb share a common transport pathway in C. reinhardtii at environmentally relevant metal concentrations.

  12. 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.

  13. 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.

  14. PENGARUH LOGAM BERAT Cd, Pb TERHADAP PERUBAHAN WARNA BATANG DAN DAUN SAYURAN

    Directory of Open Access Journals (Sweden)

    Hening Widowati

    2011-04-01

    Full Text Available Cd, Pb heavy metal absorption in aquatic vegetables: Genjer (Limnocharis flava, Kangkung air (Ipomoea aquatica Forsk dan Selada air (Nasturtium officinale R. Br, studied to see the relationship with green figure scale. The research objective was to identify the accumulated Cd, Pb in the consumed organ vegetable, and their impacts to the levels of green figure scale. The research was undertaken by planting three kinds of the aquatic vegetables to the contaminated pure Cd,pure Pb media, mixture of Cd and Pb with factorial randomized block design. Data were analyzed by factorial One-Way Anova and further test of Duncan and HSD to see the difference of Cd, Pb and green figure scale, regression and correlation to know the contribution of Cd, Pb in influencing the green figure scale. Variety of vegetables, media, organ, and the interaction influences the accumulation of Cd, Pb and level of green figure scale. There is a relationship between Cd, Pb metal accumulation to the level of green figure scale of the aquatic vegetables, with negative correlation that Cd, Pb decreased the vegetable green figure scale.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. Mineralogy and geochemistry of the argentiferous Pb-Zn and Cu veins of the Çolaklı´ area, Elazig, Eastern Turkey

    Science.gov (United States)

    Sagiroglu, Ahmet; Sasmaz, Ahmet

    2004-03-01

    The studied Pb-Zn and Cu veins occur as N-S trending and vertically dipping features in quartz diorite of Coniacian-Campanian Elazig Magmatic Complex. The complex has characteristics typical of arc magmatism and is composed of granitoids and, volcanic, subvolcanic and pyroclastic rocks. The veins are 0.5-2.5 m. thick and their lengths reach up to 750 m. The ore of veins are either massive or disseminated in gangue of carbonate minerals, quartz and barite. The veins display two sets of mineral assemblages: (1) Pb-Zn veins are composed of galena, freibergite, barite, sphalerite, chalcopyrite, pyrite, a Pb-Cl phase and native silver; (2) Cu veins have a mineral association of chalcopyrite, pyrite, galena, sphalerite, cubanite, bismuthinite and fahlore. The ore bodies are accompanied by narrow but intensely developed wall rock alterations of argillization, carbonatization and silicification. Chemical analyses of ore samples indicate high Pb, Ag, Sb, Zn, Ba and Cu contents in the veins and high correlation values between Pb-Ag, Pb-Ba, Pb-Zn, Sb-Ag, Cd-Sb and Ba-Cd. The REE geochemistry points to ore deposition under acidic conditions and probably as a product of the final stages of magmatism. Field, microscopic and geochemical data also indicate that the ores are related to the last phases of the magmatic activity of the Elazig Magmatic Complex.

  1. [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.

  2. 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.

  3. 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

  4. Remediation of Biological Organic Fertilizer and Biochar in Paddy Soil Contaminated by Cd and Pb

    Directory of Open Access Journals (Sweden)

    MA Tie-zheng

    2015-02-01

    Full Text Available The effect of application of biological organic fertilizer and biochar on the immobilized remediation of paddy soil contaminated by Cd and Pb was studied under the field experiment. The results showed that biological organic fertilizer and biochar increased the soil pH and soil nutrient contents, and reduced the soil available Cd and Pb concentrations significantly. The soil pH had significantly negative correla-tion with the soil available Cd and Pb contents. The application of biological organic fertilizer and biochar decreased Cd and Pb concentration in all parts of the rice plant, with Cd concentration in brown rice decrease by 22.00% and 18.34% and Pb decease in brown rice by 33.46% and 12.31%. The concentration of Cd and Pb in brown rice had significant positive correlation with the soil available Cd and Pb concentra-tions. It was observed that both biological organic fertilizer and biochar had a positive effect on the remediation of paddy soil contaminated by Cd and Pb.

  5. 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.

  6. 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

  7. 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. Copyright © 2016. Published by Elsevier Inc.

  8. 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.

  9. Microstructure-Wear Resistance Correlation and Wear Mechanisms of Spark Plasma Sintered Cu-Pb Nanocomposites

    Science.gov (United States)

    Sharma, Amit Siddharth; Biswas, Krishanu; Basu, Bikramjit

    2014-01-01

    The dispersion of a softer phase in a metallic matrix reduces the coefficient of friction (COF), often at the expense of an increased wear rate at the tribological contact. To address this issue, unlubricated fretting wear tests were performed on spark plasma sintered Cu-Pb nanocomposites against bearing steel. The sintering temperature and the Pb content as well as the fretting parameters were judiciously selected and varied to investigate the role of microstructure (grain size, second-phase content) on the wear resistance properties of Cu-Pb nanocomposites. A combination of the lowest wear rate (~1.5 × 10-6 mm3/Nm) and a modest COF (~0.4) was achieved for Cu-15 wt pct Pb nanocomposites. The lower wear rate of Cu-Pb nanocomposites with respect to unreinforced Cu is attributed to high hardness (~2 to 3.5 GPa) of the matrix, Cu2O/Fe2O3-rich oxide layer formation at tribological interface, and exuding of softer Pb particles. The wear properties are discussed in reference to the characteristics of transfer layer on worn surface as well as subsurface damage probed using focused ion beam microscopy. Interestingly, the flash temperature has been found to have insignificant effect on the observed oxidative wear, and alternative mechanisms are proposed. Importantly, the wear resistance properties of the nanocomposites reveal a weak Hall-Petch-like relationship with grain size of nanocrystalline Cu.

  10. 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

  11. 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.

  12. Analysis of Cu and Pb in the sediments of Kakum River, its estuary ...

    African Journals Online (AJOL)

    DR GATSING

    This paper discusses the levels of some heavy metals (Cu and Pb) in the soil sediments of the Kakum. River, its estuary and ... Keywords: River Kakum, soil sediment, Copper and Lead. ..... and active tailings pile in the State of. Mexico.

  13. 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+.

  14. 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.

  15. 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 ...

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Onderzoek monsters grond op Cd en Pb t.g.v. Cd-calamiteit door de brand te Swifterbant

    NARCIS (Netherlands)

    Berghmans-van Megen, E.H.J.; Hoff, A.W.; Horstman, H.J.; Hovens, J.P.C.; Teeuwen, J.J.M.H.; Veen, van der N.G.

    1980-01-01

    Dit verslag geeft de resultaten van het onderzoek van landbouwprodukten op Cd en Pb, genomen in de omgeving van Swifterbant en geanalyseerd op het RIKILT. Voor Cd in spinazie zijn t.o.v . het voorlopige LAC-normvoorstel geen problemen te verwachten. Over de genomen monsters , bestaande uit erwtenloo

  1. 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.

  2. 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%.

  3. 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.

  4. 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

  5. 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 ...

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Polyaniline nanofibers assembled on alginate microsphere for Cu2+ and Pb2+ uptake.

    Science.gov (United States)

    Jiang, Nina; Xu, Yiting; Dai, Yuqiong; Luo, Weiang; Dai, Lizong

    2012-05-15

    Polyaniline (PANI) nanofibers were assembled on the micro- or millimeter-scale calcium alginate (CA) beads by "competitive adsorption-restricted polymerization" approach. The CA beads made the dimensional expansion of PANI nanofibers evident, which overcame the serious aggregation of PANI nanofibers and benefited the practical operation of PANI nanofibers. Batch adsorption results showed that the millimeter-scale CA beads decorated by PANI nanofibers had high affinity to Cu(2+) and Pb(2+) in aqueous solutions. The removal percentages of Cu(2+) and Pb(2+) in aqueous solutions by this PANI/CA composite with milli/nano hierarchical structure surpassed 90% in a wide pH range from 3 to 7. Sorption of the two kinds of ions to PANI/CA composite sorbent agreed well with the Freundlich adsorption model. The adsorption kinetic results of Cu(2+) and Pb(2+) showed that the adsorption reached equilibrium within 120min and 40min, respectively. And their adsorption rates could be described by pseudo-second-order kinetics. The desorption percentages of Pb(2+) and Cu(2+) from this PANI/CA composite are 62% and 75%, respectively. The Pb(2+) and Cu(2+) removal capacity of the sorbent could be further reinforced when the diameter of CA beads turned from millimeter to micrometer. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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) .

  4. Sorption selectivity of birnessite particle edges: a d-PDF analysis of Cd(ii) and Pb(ii) sorption by δ-MnO2 and ferrihydrite.

    Science.gov (United States)

    van Genuchten, Case M; Peña, Jasquelin

    2016-08-10

    Birnessite minerals (layer-type MnO2), which bear both internal (cation vacancies) and external (particle edges) metal sorption sites, are important sinks of contaminants in soils and sediments. Although the particle edges of birnessite minerals often dominate the total reactive surface area, especially in the case of nanoscale crystallites, the metal sorption reactivity of birnessite particle edges remains elusive. In this study, we investigated the sorption selectivity of birnessite particle edges by combining Cd(ii) and Pb(ii) adsorption isotherms at pH 5.5 with surface structural characterization by differential pair distribution function (d-PDF) analysis. We compared the sorption reactivity of δ-MnO2 to that of the nanomineral, 2-line ferrihydrite, which exhibits only external surface sites. Our results show that, whereas Cd(ii) and Pb(ii) both bind to birnessite layer vacancies, only Pb(ii) binds extensively to birnessite particle edges. For ferrihydrite, significant Pb(ii) adsorption to external sites was observed (roughly 20 mol%), whereas Cd(ii) sorption was negligible. These results are supported by bond valence calculations that show comparable degrees of saturation of oxygen atoms on birnessite and ferrihydrite particle edges. Therefore, we propose that the sorption selectivity of birnessite edges follows the same order of that reported previously for ferrihydrite: Ca(ii) < Cd(ii) < Ni(ii) < Zn(ii) < Cu(ii) < Pb(ii).

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Bioaccumulation of Heavy Metals (Zn, Pb, Cu and Cd) by

    African Journals Online (AJOL)

    2-6 times higher than the levels accumulated in control animals. With regards .... In this series of experiments, T. fuscatus was exposed ... water to remove debris, plankton and other external ..... reference to United Kingdom estuaries: A review.

  10. 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.

  11. 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.

  12. 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

  13. 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.``

  14. 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.

  15. 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.

  16. 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.

  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. REHABILITASI TANAH SAWAH TERCEMAR LOGAM BERAT Pb DAN Cd MELALUI FITOREMEDIASI

    Directory of Open Access Journals (Sweden)

    Sandra Sukmaning Adji

    2016-09-01

    Full Text Available It is indicated that rice field soil and plants on Rancaekek Bandung is containing heavy metal elements. This research aims to find out rehabilitation method for rice field soil by phytoremediation. Experiment was conducted in greenhouse. Vegetation used for this research were eceng gondok, mendong, akar wangi and haramay. The vegetation treatment was conducted under greenhouse experiments using Complete Randomized Design (CRD. Result showed that the use of vegetation had reduced the volume of Pb and Cd in the soil. Heavy metals are also contained within the roots and the leaves of the indicator plants. Mendong contained the highest concentration of Pb accumulated in its root, while akar wangi was indicated as contained Cd in its roots. Eceng gondok was indicated as containing the highest consentration of Pb and Cd accumulated in its leaves

  19. 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).

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. LEVELS OF As, Pb, Cd AND Fe IN SUSPENDED PARTICULATE ...

    African Journals Online (AJOL)

    DR. AMIN

    The calculated enrichment factor revealed Cd to be highly .... calculated by the following formular: SPM = Wp/Vair, ... Absorption Spectrophotometer (Buck Scientific Model -. 200A/213) with ... also be attributed to meteorological factors such as.

  8. 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.

  9. 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.

  10. Pre-concentration of Pb, Cd, and Ni in river water using back extraction method

    Science.gov (United States)

    Koesmawati, T. A.; Moelyo, M.; Rizqiani, A.; Tanuwidjaja, S.

    2017-03-01

    Dissolved heavy metals such as Pb, Cd and Ni in natural water can be the source of harmful contaminant for human health and aquatic life in aquatic systems. Particular treatment is needed for low concentration of metals in water samples using Flame Atomic Absorption Spectrophotometer (FAAS) measurement. The sample was collected from Cikapundung River in Siliwangi and Dayeuhkolot, Bandung. Back-extraction procedure was used as an alternative method for pre-concentration in trace metal analysis. Ammonium Pyrrolidine Dithiocarbamate (APDC) and Diethylammonium Diethyldithiocarbamate (DDDC) in Methyl Isobuthyl Ketone (MIBK) were used as chelating agent. In this study, the application of back-extraction procedure using APDC/DDDC chelating agent in MIBK resulted the detection limit of 2.2 μg/L for Pb; 1.6 μg/L for Cd; and 1.0 μg/L for Ni. The result showed that sensitivity was increased 4 times for Pb, 6 times for Ni, and none for Cd. The highest concentration of Pb in Cikapundung River was found 8.0 μg/L. All Ni concentration in water samples were under limit of detection. Method validation was conducted in this study and found that the value of correlation coefficient (r) for Pb, Cd and Ni was 0.9995, 0.9960 and 0.9994, respectively. The recovery value for Pb, Cd and Ni were 112.0, 81.5 and 85.9%, respectively in Cikapundung River, and 119.0, 83.5 and 85.9 %, respectively, in groundwater samples. The value of Relative Standard Deviation (RSD) for Pb, Cd and Ni in Cikapundung River were 2.01, 2.15 and 6.40%, respectively. On the other hand, the value of RSD of Pb, Cd and Ni in groundwater were 2.70, 3.30 and 7.69%, respectively. In conclusion, back-extraction method can be applied as pre-concentration for low concentration of Pb and Ni in river water samples.

  11. 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.

  12. 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

  13. 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...

  14. 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.

  15. 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.

  16. [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.

  17. [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.

  18. 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

  19. CdO necklace like nanobeads decorated with PbS nanoparticles: Room temperature LPG sensor

    Energy Technology Data Exchange (ETDEWEB)

    Sonawane, N.B. [Department of Physics, School of Physical Sciences, North Maharashtra University, Jalgaon, 425001 M.S. (India); K.A.M.P. & N.K.P. Science College, Pimpalner, Sakri, Dhule, M.S. (India); Baviskar, P.K. [Department of Physics, School of Physical Sciences, North Maharashtra University, Jalgaon, 425001 M.S. (India); Ahire, R.R. [S.G. Patil Science, Sakri, Dhule, M.S. (India); Sankapal, B.R., E-mail: brsankapal@gmail.com [Nano Materials and Device Laboratory, Department of Applied Physics, Visvesvaraya National Institute of Technology, South Ambazari Road, Nagpur, 440010 M.S. (India)

    2017-04-15

    Simple chemical route has been employed to grow interconnected nanobeads of CdO having necklace like structure through air annealing of cadmium hydroxide nanowires. This nanobeads of n-CdO with high surface area has been decorated with p-PbS nanoparticles resulting in the formation of nano-heterojunction which has been utilized effectively as room temperature liquefied petroleum gas (LPG) sensor. The room temperature gas response towards C{sub 2}H{sub 5}OH, Cl{sub 2}, NH{sub 3}, CO{sub 2} and LPG was investigated, among which LPG exhibits significant response. The maximum gas response of 51.10% is achieved with 94.54% stability upon exposure of 1176 ppm concentration of LPG at room temperature (27 °C). The resulting parameters like gas response, response and recovery time along with stability studies has been studied and results are discussed herein. - Highlights: • Conversion of Cd(OH){sub 2} nanowires to CdO nanonecklace by air annealing at 290 °C. • Decoration of PbS nanoparticles over CdO nanobeads by SILAR method. • Formation of n-CdO/p-PbS nano-heterojunction as room temperature LPG sensor. • Maximum gas response of 51.10% with 94.54% stability.

  20. 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).

  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. 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.

  3. Assessing Pb,Zn,Cd contamination in stream sediments of south east Tehran (Iran)

    Science.gov (United States)

    Shahdadi, S.; Fayazi, F.; Yaghoobpour, A.; Rahmani, F.; Moslempour, M.

    2009-04-01

    Assessing Pb,Zn,Cd contamination in stream sediments of south east Tehran (Iran) 31 sediment samples collected from south east of Tehran around cement plant (Bibi shahrbanoo mountain) were analyzed by ICP for Pb, Zn, Cd. The samples were also investigated for mineralogy using X-ray analysis.The clay mineral assemblage encountered in the analyzed samples is composed of vermiculite, dickite, montmorillonite and kaolinite.The non-clay minerals of the mud-sized fraction are composed mainly of quartz and calcite and dolomite as major minerals with albite, hematite, muscovite as minor minerals. The measured metals correlated positively with the determined physiochemical factors such as pH, clay content, organic matter content, and carbonate content. According to the index of geoaccumulation, the sediments of the study area are considered to be strongly to very strongly polluted with respect to Pb, strongly polluted with respect to Zn, and moderatly to strongly polluted with recpect to Cd.The calculation of enrichment factors shows that the source of Pb and Zn is from antropogenic activites such as cement plant and vehicle exhausts and Cd from natural source.

  4. KINETIC AND EQUILIBRIUM STUDIES OF Pb(II) AND Cd(II ...

    African Journals Online (AJOL)

    and 40.00 mg/g for Cd(II) and Pb(II) ions, respectively. ... influence of initial metal concentration, temperature, pH and adsorbent dose were studied in order to obtain maximum ...... Volesky, B.; Holan, Z.R. Biotechnol. Progress 1995, 1, 235. 9.

  5. Behaviours of MeCl2 (Me: Pb and Cd) during thermal treatment of ...

    African Journals Online (AJOL)

    hope&shola

    Key words: Toxic element,kaolin, lime, silica, heat-treatment, leaching. INTRODUCTION ... including Pb and Cd as well as waste derived ashes are often used to ... by using an inductively coupled plasma atomic emission spectrophotometer. ..... removal of cadmium from a gasification flue gas using solid sorbents. Fuel, 84: ...

  6. 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...

  7. The accumulation of heavy metals (Cd, Pb, Hg, Cr) and their state in ...

    African Journals Online (AJOL)

    ONOS

    2010-01-25

    Jan 25, 2010 ... metals (Cd, Pb, Hg and Cr) in the water and plankton of Beysehir and ... In addition, heavy metals show harmful effects ... in laboratory for a period of time for evaporation of water. ...... biochemical effects in an estuarine teleost.

  8. 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.

  9. 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.

  10. STABILITY OF BINARY COMPLEXES OF Pb(II), Cd(II) AND Hg(II ...

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. Binary complexes of maleic acid with toxic metal ions such as Pb(II), Cd(II) and Hg(II) have been ... By binding the metal ions electrostatically to the negatively charged ..... results in highly stable seven membered rings (Figure 3).

  11. 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.

  12. 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.

  13. Tracing Cd, Zn and Pb pollution sources in bivalves using isotopes

    Science.gov (United States)

    Shiel, A. E.; Weis, D. A.; Orians, K. J.

    2010-12-01

    In a multi-tracer study, Cd, Zn and Pb isotopes (MC-ICP-MS) and elemental concentrations (HR-ICP-MS) are evaluated as tools to distinguish between natural and anthropogenic sources of these metals in bivalves from western Canada (British Columbia), the eastern USA, Hawaii and France. High Cd concentrations found in BC oysters have elicited economic and health concerns. The source of these high Cd levels is unknown but thought to be largely natural. High Cd levels in BC oysters are largely attributed to the natural upwelling of Cd-rich intermediate waters in the North Pacific as the δ114/110Cd (-0.69 to -0.09‰) and δ66/64Zn (0.28 to 0.36‰) values of BC oysters fall within the range reported for North Pacific seawater. Different contributions from anthropogenic sources account for the variability of Cd isotopic compositions of BC oysters; the lightest of these oysters are from the BC mainland. These oysters also have Pb isotopic compositions that reflect primarily anthropogenic sources (e.g., leaded and unleaded automotive gasoline and smelting of Pb ores, potentially historical). On the contrary, USA East Coast bivalves exhibit relatively light Cd isotopic compositions (δ114/110Cd = -1.20 to -0.54‰; lighter than reported for North Atlantic seawater) due to the high prevalence of industry on this coast. The Pb isotopic compositions of these bivalves indicate contributions from the combustion of coal. The large variability of environmental health among coastal areas in France is reflected in the broad range of Cd isotopic compositions exhibited by French bivalves (δ114/110Cd = -1.08 to -0.20‰). Oysters and mussels from the Marennes-Oléron basin and Gironde estuary have the lightest Cd isotopic compositions of the French oysters consistent with significant historical Cd emissions from the now-closed proximal Zn smelter. In these bivalves, significant declines in the Cd levels between 1984/7 and 2004/5 are not accompanied by a significant shift in the Cd

  14. 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.

  15. 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...

  16. 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.

  17. Removal and Preconcentration of Pb (II and Cd (II by Zero-Valent Iron Nanoparticles in Contaminated Water

    Directory of Open Access Journals (Sweden)

    Shiralipour

    2015-04-01

    Full Text Available Background Lead (Pb and cadmium (Cd are two of the hazardous metals in the environment due to their acute and chronic effects on human health. Zero-valent iron nanoparticles (ZVINPs are one of the adsorbents proposed as an efficient adsorbent for Pb and Cd. Objectives This study evaluated the quantitative removal efficiency of Pb and Cd ions from contaminated water by ZVINPs. In addition, the capability of ZVINPs as a solid phase extractor for preconcentration and determination of Pb and Cd was investigated. Materials and Methods Four samples, each from different water sources like Well water (Shushtar, Iran, Karoon River (Ahvaz, Iran, Caspian Sea (northern Iran and Persian Gulf (southern Iran were collected. Results The elapsed time for quantitative removal of both Pb and Cd ions was two minutes. This method is applicable in a widespread range of pH and relatively high concentrations of electrolyte (NaCl for the efficient removal (> 99% of Pb and Cd ions in water samples. The adsorption of Pb and Cd ions on ZVINPs was well followed by the Langmuir model. The maximum adsorption amounts of Pb and Cd ions on ZVINPs were 96.5 and 58.3 mg/g, respectively. Limits of detection (LODs of the method for lead and cadmium ions were 0.015 and 0.002 mg/L, respectively. The relative standard deviations for ten replicate determinations (Pb2+ 0.3 mg/L, Cd2+ 0.03 mg/L were below 5%. The enrichment factors were more than 16 and 14 for Pb2+ and Cd2+, respectively. Conclusions The proposed method is simple, fast, cost-effective and safe for the environment.

  18. 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.

  19. Effects of Sewage Sludge and Chemical Fertilizers on Pb and Cd Accumulation in Fenugreek (Trigonella gracum

    Directory of Open Access Journals (Sweden)

    Mehrdad Cheraghi

    2015-09-01

    Full Text Available Background: Reprocessing of sewage sludge to agricultural land is preferred to disposal through landfill or incineration due to its potentially beneficial effects on soil fertility from organic matter and plant nutrients, such as N and P, present in the sludge. Therefore, this study was conducted to investigate the impact of sewage sludge and chemical fertilizers on Pb and Cd accumulation in fenugreek, Trigonella gracum. Methods: The experiment was carried out in earthen pots, 30 cm in diameter and 30 cm in depth. The study was done on five groups- control, S1: sewage sludge (50 tone/ha, S2: sew-age sludge (50 tone/ha+heavy metals [85 ppm of Cd(Cl2; 840 ppm of Pb(NO32], F1: chemi-cal fertilizer (250 kg/ha, and F2: chemical fertilizer (250 kg/ha+ heavy metals [85 ppm of Cd(Cl2; 840 ppm of Pb(NO32]- in three replicates. Results: The results showed that total Pb concentrations ranged from 0.05 to 2 mg/kg, with the maximum level in the sewage sludge treatment (S2 while Cd concentrations in the plant ranged from 0.07 to 1.1 mg/kg with the maximum content in the chemical fertilizer treatment (F2. The concentrations of Pb and Cd in vegetables were significantly higher than the permis-sible limits. Conclusion: This study highlights the potential risks involved in the cultivation and consump-tion of vegetables on plots irrigated with sewage sludge, a practice which may endanger the health of urban populations that consume these vegetables.

  20. 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.

  1. 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

  2. Uptake and accumulation of potentially toxic metals (Zn, Cu and Pb) in soils and plants of Durgapur industrial belt.

    Science.gov (United States)

    Kisku, Ganesh Chandra; Pandey, Poonam; Negi, Mahendra Pratap Singh; Misra, Virendra

    2011-11-01

    Uptake and accumulation of metals in crops may cause possible health risks through food chain. A field survey was conducted to investigate the accumulation of potentially toxic metals contamination in soil and plants irrigated with complexed industrial effluents. Concentration of Zn, Cu and Pb was 205-255,101-130,118-177 microg g(-1) in rhizosphere soils and 116-223, 57-102 and 63-95 microg g(-1) d. wt. in root and 95-186, 44-75 and 27-58 microg g(-1) d. wt. in shoot, respectively. The trend in Cu and Pb was in the order: soil > root > shoot > seed while in Zn it was soil > root > seed > shoot. Roots accumulated a larger fraction of soil Cu (70%) > Zn (67%) > Pb (54%). Bioaccumulation coefficient of soil to root ranged from 51-98 for Zn, 54-85 for Cu and 43-63 for Pb.Analysis of variance showed marginal change in bioaccumulation coefficient, noticed between plants (p > 0.05) while it varied significantly (p shoot > seed/fruit) while decreased between metals from Zn to Pb (Zn > Cu > Pb). Out of the three, two Cu and Pb accumulated to phyotoxic levels while Zn was within threshold limit of phytotoxicity.

  3. 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...

  4. 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.

  5. 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.

  6. 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.

  7. Monte-Carlo simulation of {Pb}/{Cu (100) } surface superstructures

    Science.gov (United States)

    Tan, S.; Ghazali, A.; Lévy, J.-C. S.

    1997-04-01

    Three surface superstructures of {Pb}/{Cu (100) } at low lead coverage are well known experimentally: c(4 × 4),c(2 × 2) and c(5√2×√2)R45°. The present study consists in (i) using generalized Lennard-Jones pair potentials for lead-lead and copper-copper interactions fitted on structural and elastic bulk properties, (ii) deriving an effective potential for lead-copper and (iii) developing a Monte-Carlo extensive relaxation of superstructure models. The MC simulations reveal the stability of these approximate superstructures and yield structural details that are all observed in STM and LEED experiments: the adlayer corrugation, surface alloying, structural modulations as well as PbPb and PbCu spacings. The simulated results on structures and on melting temperatures are in close agreement with experimental data.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

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

    Science.gov (United States)

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

    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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

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

    Science.gov (United States)

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

    2006-03-01

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

  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. Fabrication of carbon nanotubes paste electrode for determination of Cd (II) and Pb (II) ions

    Science.gov (United States)

    Le Hai, Tran; Hai, Tran Duy

    2017-09-01

    In this study, the electrode for determination of Cd (II) and Pb (II) was prepared by a paste composition of multi-wall carbon nanotubes (MWCNTs) and paraffin oil as a binder. Effect of MWCNTs/paraffin oil ratio on electrochemical behaviors of the electrodes was investigated. For the characterization of the fabricated MWCNT paste electrodes, the cyclic voltammetry, SEM images, RAMAN and XRD spectroscopy were employed. It was found that the electrode containing 20% (w/w) paraffin oil and 80 % (w/w) MWCNTs exhibited the satisfactory properties through the anodic stripping voltammetry (ASV) results. This electrode showed a reversible redox process with an electrochemical mechanism of controlled diffusion. Furthermore, the ASV results of the prepared electrode revealed a linear response of Pb (II) and Cd (II) concentrations with a detection limit of 6.33 µmol.L-1 and 0.42 µmol.L-1, respectively

  10. 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.

  11. 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.

  12. CdS/PbSe heterojunction for high temperature mid-infrared photovoltaic detector applications

    Energy Technology Data Exchange (ETDEWEB)

    Weng, Binbin, E-mail: binbinweng@ou.edu, E-mail: shi@ou.edu; Qiu, Jijun; Zhao, Lihua; Chang, Caleb [The School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019 (United States); Shi, Zhisheng, E-mail: binbinweng@ou.edu, E-mail: shi@ou.edu [The School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019 (United States); Nanolight, Inc., Norman, Oklahoma 73069 (United States)

    2014-03-24

    n-CdS/p-PbSe heterojunction is investigated. A thin CdS film is deposited by chemical bath deposition on top of epitaxial PbSe film by molecular beam epitaxy on Silicon. Current-voltage measurements demonstrate very good junction characteristics with rectifying ratio of ∼178 and ideality factor of 1.79 at 300 K. Detectors made with such structure exhibit mid-infrared spectral photoresponse at room temperature. The peak responsivity R{sub λ} and specific detectivity D{sup *} are 0.055 A/W and 5.482 × 10{sup 8} cm·Hz{sup 1/2}/W at λ = 4.7 μm under zero-bias photovoltaic mode. Temperature-dependent photoresponse measurements show abnormal intensity variation below ∼200 K. Possible reasons for this phenomenon are also discussed.

  13. 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.

  14. [Impact of polymetallic mine (Zn, Pb, Cu) residues on surface water, sediments and soils at the vicinity (Marrakech, Morocco)].

    Science.gov (United States)

    El Adnani, M; Rodriguez-Maroto, J M; Sbai, M L; Loukili Idrissi, L; Nejmeddine, A

    2007-09-01

    Metal sulphide tailings present a potential risk for the environment because of their natural oxidability which leads to the production of acid mine drainage. The prospected site close to Marrakech includes zinc, lead and copper sulphide deposits. This site is located in an agricultural area near the Tensift River which is used for irrigation. In addition to the tailing leachates, underground mine waters are also discharged into the river. This represents a potential risk for the environment and human health. The aim of this study was to assess the tailings impact on surface water, sediments and soil qualities. Chemical analysis of surface water and sediments collected downstream of the mine revealed that, water and sediments present high concentrations of major ions and heavy metals. The analysis also revealed spatial as well as temporal changes in the chemical properties of the studied water and sediments. These changes are attributed to the rising phenomena. The soil near the mine presents high content of sulphate. Its Zn, Pb, Cu and Fe contents are respectively 38, 15, 11 and 1.6 times higher than non contaminated soils located far away from the site. The soil irrigated with underground mine waters shows concentrations of SO4(2-), Cu, Zn, Fe, Cd and Pb which are respectively 4, 10, 28, 2, 9 and 12 times higher than soils which are not irrigated with this mine water. This study also showed that there has been a change in the physicochemical characteristics of water and sediments in the sampling points downstream of the mine before its closure and after its activity renewal.

  15. 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.

  16. Zn, Pb, Cr and Cd concentrations in fish, water and sediment from ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Manage. Feb. 2017. Vol. 21 (1) 87-91. Full-text Available Online at www.ajol.info and ... Rivers State University of Science and Technology Nkpolu ,. PMB 5080 ... alongside information on health risk associated with ... top 2cm of sediment surface using a benthic grab, ... Cd = 1x10-3, Pb = 4x10-3, Cr = 1.5 and Zn = 3x10-1.

  17. 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...

  18. 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.

  19. 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.

  20. 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.

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

    Science.gov (United States)

    Dong, De-ming; Yang, Fan; Li, Yu; Hua, Xiu-yi; Lü, 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 degrees C 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.

  2. 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.

  3. 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.

  4. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. 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+}.

  6. 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 ...

  7. 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

  8. 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.

  9. 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.

  10. Sensitive electrochemical sensor using a graphene–polyaniline nanocomposite for simultaneous detection of Zn(II), Cd(II), and Pb(II)

    Energy Technology Data Exchange (ETDEWEB)

    Ruecha, Nipapan [Program in Macromolecular Science, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330 (Thailand); Rodthongkum, Nadnudda [Metallurgy and Materials Science Research Institute, Chulalongkorn University, Soi Chula 12, Phayathai Road, Patumwan, Bangkok 10330 (Thailand); Cate, David M. [Department of Biomedical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States); Volckens, John [Department of Biomedical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States); Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States); Chailapakul, Orawon, E-mail: orawon@chula.ac.th [Electrochemistry and Optical Spectroscopy Research Unit (EOSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330 (Thailand); National Center of Excellence for Petroleum, Petrochemicals, Advanced Materials, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330 (Thailand); Henry, Charles S., E-mail: chuck.henry@colostate.edu [Department of Biomedical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States); Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523 (United States)

    2015-05-18

    Highlights: • Detection limits for Zn, Pb, and Cd using ASV were 1, 0.1, and 0.1 μg L{sup −1}, respectively. • G/PANI-modification led to a 3× improvement in signal vs. unmodified electrodes. • ASV on a plastic substrate exhibited better sensitivity than on a paper substrate. • Zn, Pb, and Cd were measured in human serum using method of standard addition. - Abstract: This work describes the development of an electrochemical sensor for simultaneous detection of Zn(II), Cd(II), and Pb(II) using a graphene–polyaniline (G/PANI) nanocomposite electrode prepared by reverse-phase polymerization in the presence of polyvinylpyrrolidone (PVP). Two substrate materials (plastic film and filter paper) and two nanocomposite deposition methods (drop-casting and electrospraying) were investigated. Square-wave anodic stripping voltammetry currents were higher for plastic vs. paper substrates. Performance of the G/PANI nanocomposites was characterized by scanning electron microscopy (SEM) and cyclic voltammetry. The G/PANI-modified electrode exhibited high electrochemical conductivity, producing a three-fold increase in anodic peak current (vs. the unmodified electrode). The G/PANI-modified electrode also showed evidence of increased surface area under SEM. Square-wave anodic stripping voltammetry was used to measure Zn(II), Cd(II), and Pb(II) in the presence of Bi(III). A linear working range of 1–300 μg L{sup −1} was established between anodic current and metal ion concentration with detection limits (S/N = 3) of 1.0 μg L{sup −1} for Zn(II), and 0.1 μg L{sup −1} for both Cd(II) and Pb(II). The G/PANI-modified electrode allowed selective determination of the target metals in the presence of common metal interferences including Mn(II), Cu(II), Fe(III), Fe(II), Co(III), and Ni(II). Repeat assays on the same device demonstrated good reproducibility (%RSD < 11) over 10 serial runs. Finally, this system was utilized for determining Zn(II), Cd(II), and Pb(II) in

  11. Effect of dissolved organic matter (DOM) of contrasting origins on Cu and Pb speciation and toxicity to Paracentrotus lividus larvae

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Marin, Paula, E-mail: paulasanchez@uvigo.es [Laboratorio de Ecoloxia Marina (LEM), Universidade de Vigo, Campus Universitario, 36310 Vigo, Galicia (Spain); Santos-Echeandia, Juan; Nieto-Cid, Mar; Alvarez-Salgado, Xose Anton [Instituto de Investigacions Marinas, Consejo Superior de Investigaciones Cientificas (CSIC), Eduardo Cabello 6, 36208 Vigo, Galicia (Spain); Beiras, Ricardo [Laboratorio de Ecoloxia Marina (LEM), Universidade de Vigo, Campus Universitario, 36310 Vigo, Galicia (Spain)

    2010-01-31

    Water samples of contrasting origin, including natural seawater, two sediment elutriates and sewage-influenced seawater, were collected and obtained to examine the effect of the dissolved organic matter (DOM) present on metal bioavailability. The carbon content (DOC) and the optical properties (absorbance and fluorescence) of the coloured DOM fraction (CDOM) of these materials were determined. Cu and Pb complexation properties were measured by anodic stripping voltammetry (ASV) and the effect of DOM on Cu and Pb bioavailability was studied by means of the Paracentrotus lividus embryo-larval bioassay. Sediment elutriates and sewage-influenced water (1) were enriched 1.4-1.7 times in DOC; (2) absorbed and reemitted more light; and (3) presented higher Cu complexation capacities (L{sub Cu}) than the natural seawater used for their preparation. L{sub Cu} varied from 0.08 {mu}M in natural seawater to 0.3 and 0.5 {mu}M in sediment elutriates and sewage-influenced water, respectively. Differences in DOC, CDOM and Cu complexation capacities were reflected in Cu toxicity. DOM enriched samples presented a Cu EC{sub 50} of 0.64 {mu}M, significantly higher than the Cu EC{sub 50} of natural and artificial seawater, which was 0.38 {mu}M. The protecting effect of DOM on Cu toxicity greatly disappeared when the samples were irradiated with high intensity UV-light. Cu toxicity could be successfully predicted considering ASV-labile Cu concentrations in the samples. Pb complexation by DOM was only detected in the DOM-enriched samples and caused little effect on Pb EC{sub 50}. This effect was contrary for both elutriates: one elutriate reduced Pb toxicity in comparison with the control artificial seawater, while the other increased it. UV irradiation of the samples caused a marked increase in Pb toxicity, which correlated with the remaining DOC concentration. DOM parameters were related to Cu speciation and toxicity: good correlations were found between DOC and Cu EC{sub 50}, while L

  12. 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.

  13. 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.

  14. Determination of Cd, Cr and Pb in phosphate fertilizers by laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, Lidiane Cristina; Gustinelli Arantes de Carvalho, Gabriel [NAPTISA Research Support Center “Technology and Innovation for a Sustainable Agriculture”, Center for Nuclear Energy in Agriculture, University of São Paulo, Av. Centenário 303, 13416-000, Piracicaba SP (Brazil); Santos, Dario [Federal University of São Paulo, R. Prof. Artur Riedel 275, 09972-270, Diadema SP (Brazil); Krug, Francisco José, E-mail: fjkrug@cena.usp.br [NAPTISA Research Support Center “Technology and Innovation for a Sustainable Agriculture”, Center for Nuclear Energy in Agriculture, University of São Paulo, Av. Centenário 303, 13416-000, Piracicaba SP (Brazil)

    2014-07-01

    A validated method for quantitative determination of Cd, Cr, and Pb in phosphate fertilizers by laser-induced breakdown spectroscopy (LIBS) is presented. Laboratory samples were comminuted and homogenized by cryogenic or planetary ball milling, pressed into pellets and analyzed by LIBS. The experimental setup was designed by using a Q-switched Nd:YAG at 1064 nm with 10 Hz repetition rate, and the intensity signals from Cd II 214.441 nm, Cr II 267.716 nm and Pb II 220.353 nm emission lines were measured by using a spectrometer furnished with an intensified charge-coupled device. LIBS parameters (laser fluence, lens-to-sample distance, delay time, integration time gate, number of sites and number of laser pulses per site) were chosen after univariate experiments with a pellet of NIST SRM 695 (Trace Elements in Multi-Nutrient Fertilizer). Calibration and validation were carried out with 30 fertilizer samples from single superphosphate, triple superphosphate, monoammonium phosphate, and NPK mixtures. Good results were obtained by using 30 pulses of 50 J cm{sup −2} (750 μm spot size), 2.0 μs delay time and 5.0 μs integration time gate. No significant differences between Cd, Cr, and Pb mass fractions determined by the proposed LIBS method and by ICP OES after microwave-assisted acid digestion (AOAC 2006.03 Official Method) were found at 95% confidence level. The limits of detection of 1 mg kg{sup −1} Cd, 2 mg kg{sup −1} Cr and 15 mg kg{sup −1} Pb and the precision (coefficients of variation of results ranging from 2% to 15%) indicate that the proposed LIBS method can be recommended for the determination of these analytes in phosphate fertilizers. - Highlights: • First LIBS application for quantitative Cd, Cr and Pb determination in fertilizers. • LIBS method was validated for analysis of phosphate fertilizers pressed pellets. • LIBS sample throughput is remarkably better than already existing methods.

  15. 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.

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

    Science.gov (United States)

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

    2015-01-01

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

  17. 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.

  18. 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.

  19. Pb/Cu (100) surface superstructures: Monte Carlo and molecular dynamics simulations

    Science.gov (United States)

    Tan, S.; Ghazali, A.; L´vy, J. C. S.

    1997-12-01

    Monte Carlo simulations with simple pair potentials of the Lennard-Jones type enable us to show the stability of the three experimentally known superstructures of Pb/Cu (100) at different lead submonolayer coverages: c(4 × 4)atθ = 3/8,c(2 × 2)atθ = 0.5 and c(5√2 × √2)R45° at θ = 0.6. In addition, numerous details of these superstructures, including interatomic distances, surface alloying, corrugation and weak modulation are obtained numerically in quantitative and qualitative accord with the experimentally observed and measured data. By molecular dynamics the melting of these structures is studied from the temperature dependence of the Pb-atom average energy and diffusion coefficient, with evidence for a first-order transition for every superstructure. The dispersion of surface phonons is also derived.

  20. 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.

  1. 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.

  2. Amino-functionalized core-shell magnetic mesoporous composite microspheres for Pb(II) and Cd(II) removal.

    Science.gov (United States)

    Tang, Yulin; Liang, Song; Wang, Juntao; Yu, Shuili; Wang, Yilong

    2013-04-01

    Amino-functionalized Fe3O4@mesoporous SiO2 core-shell composite microspheres NH2-MS in created in multiple synthesis steps have been investigated for Pb(II) and Cd(II) adsorption. The microspheres were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), N2 adsorption-desorption, zeta potential measurements and vibrating sample magnetometer. Batch adsorption tests indicated that NH2-MS exhibited higher adsorption affinity toward Pb(II) and Cd(II) than MS did. The Langmuir model could fit the adsorption isotherm very well with maximum adsorption capacity of 128.21 and 51.81 mg/g for Pb(II) and Cd(II), respectively, implying that adsorption processes involved monolayer adsorption. Pb(II) and Cd(II) adsorption could be well described by the pseudo second-order kinetics model, and was found to be strongly dependent on pH and humic acid. The Pb(II)- and Cd(II)-loaded microspheres were effectively desorbed using 0.01 mol/L HCl or EDTA solution. NH2-MS have promise for use as adsorbents in the removal of Pb(II) and Cd(II) in wastewater treatment processes.

  3. Combined effect of Cd and Pb spiked field soils on bioaccumulation, DNA damage, and peroxidase activities in Trifolium repens.

    Science.gov (United States)

    Lanier, C; Bernard, F; Dumez, S; Leclercq, J; Lemière, S; Vandenbulcke, F; Nesslany, F; Platel, A; Devred, I; Cuny, D; Deram, A

    2016-01-01

    The present study was designed to investigate the combined effects of Cd and Pb on accumulation and genotoxic potential in white clover (Trifolium repens). For this purpose, T. repens was exposed to contaminated soils (2.5-20 mg kg(-1) cadmium (Cd), 250-2000 mg kg(-1) lead (Pb) and a mixture of these two heavy metals) for 3, 10 and 56 days. The resulting bioaccumulation of Cd and Pb, DNA damage (comet assay) and peroxidase activities (APOX and GPOX) were determined. The exposure time is a determinant factor in experiments designed to measure the influence of heavy metal contamination. The accumulation of Cd or Pb resulting from exposure to the two-metal mixture does not appear to depend significantly on whether the white clover is exposed to soil containing one heavy metal or both. However, when T. repens is exposed to a Cd/Pb mixture, the percentage of DNA damage is lower than when the plant is exposed to monometallic Cd. DNA damage is close to that observed in the case of monometallic Pb exposure. Peroxidase activity cannot be associated with DNA damage under these experimental conditions.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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)

  13. 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.

  14. 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.}

  15. 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...

  16. 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.

  17. Tolerance and hyperaccumulation of a mixture of heavy metals (Cu, Pb, Hg, and Zn) by four aquatic macrophytes.

    Science.gov (United States)

    Romero-Hernández, Jorge Alberto; Amaya-Chávez, Araceli; Balderas-Hernández, Patricia; Roa-Morales, Gabriela; González-Rivas, Nelly; Balderas-Plata, Miguel Ángel

    2017-03-04

    In the present investigation, four macrophytes, namely Typha latifolia (L.), Lemna minor (L.), Eichhornia crassipes (Mart.) Solms-Laubach, and Myriophyllum aquaticum (Vell.) Verdc, were evaluated for their heavy metal (Cu, Pb, Hg, and Zn) hyperaccumulation potential under laboratory conditions. Tolerance analyses were performed for 7 days of exposure at five different treatments of the metals mixture (Cu(+2), Hg(+2), Pb(+2), and Zn(+2)). The production of chlorophyll and carotenoids was determined at the end of each treatment. L. minor revealed to be sensitive, because it did not survive in all the tested concentrations after 72 hours of exposure. E. crassipes and M. aquaticum displayed the highest tolerance to the metals mixture. For the most tolerant species of aquatic macrophytes, The removal kinetics of E. crassipes and M. aquaticum was carried out, using the following mixture of metals: Cu (0.5 mg/L) and Hg, Pb, and Zn 0.25 mg/L. The obtained results revealed that E. crassipes can remove 99.80% of Cu, 97.88% of Pb, 99.53% of Hg, and 94.37% of Zn. M. aquaticum withdraws 95.2% of Cu, 94.28% of Pb, 99.19% of Hg, and 91.91% of Zn. The obtained results suggest that these two species of macrophytes could be used for the phytoremediation of this mixture of heavy metals from the polluted water bodies.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Lime and Phosphate Amendment Can Significantly Reduce Uptake of Cd and Pb by Field-Grown Rice

    Directory of Open Access Journals (Sweden)

    Rongbo Xiao

    2017-03-01

    Full Text Available Agricultural soils are suffering from increasing heavy metal pollution, among which, paddy soil polluted by heavy metals is frequently reported and has elicited great public concern. In this study, we carried out field experiments on paddy soil around a Pb-Zn mine to study amelioration effects of four soil amendments on uptake of Cd and Pb by rice, and to make recommendations for paddy soil heavy metal remediation, particularly for combined pollution of Cd and Pb. The results showed that all the four treatments can significantly reduce the Cd and Pb content in the late rice grain compared with the early rice, among which, the combination amendment of lime and phosphate had the best remediation effects where rice grain Cd content was reduced by 85% and 61%, respectively, for the late rice and the early rice, and by 30% in the late rice grain for Pb. The high reduction effects under the Ca + P treatment might be attributed to increase of soil pH from 5.5 to 6.7. We also found that influence of the Ca + P treatment on rice production was insignificant, while the available Cd and Pb content in soil was reduced by 16.5% and 11.7%, respectively.

  5. 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.

  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. 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.

  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. 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.

  10. Contact angle study on the activation mechanisms of sphalerite with Cu(II) and Pb(II); Estudio de los mecanismos de activacion de la esfalerita con Cu(II) y Pb(II)

    Energy Technology Data Exchange (ETDEWEB)

    Davila Pulido, G. I.; Uribe Salas, A.

    2011-07-01

    This article presents results of an experimental study on the sphalerite activation with Cu(II) and Pb(II), whose main objective was to investigate the activation mechanisms and to evaluate the magnitude of the hydrophobization achieved with both chemical species. The hydrophobicity acquired by the mineral due to the interaction with the activator and collector (sodium isopropyl xanthate) is characterized making use of the contact angle technique. The results show that Cu(II) replaces the Zn of the external layers of the mineral, promoting the sulfide (S{sup 2}-) oxidation to produce a mixture of CuS, Cu{sub 2}S and S{sup o}, of hydrophobic nature. The subsequent interaction with xanthate increases the hydrophobicity of the mineral surface. In turn, Pb(II) activation of sphalerite is due to the formation of a PbS layer that reacts with xanthate to produce hydrophobic species (e.g., PbX{sub 2}). It is also observed that the hydrophobicity of sphalerite activated with Pb(II) is favored under air atmospheres, as compared to that obtained under nitrogen atmospheres. It is concluded that the hydrophobicity achieved by lead activation may be of the same order of magnitude to that deliverately induced by copper activation. (Author) 11 refs.

  11. 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.

  12. [Response of Nostoc flageliforme cell to Cu2+, Cr2+ and Pb2+ stress].

    Science.gov (United States)

    Guo, Jinying; Shi, Mingke; Zhao, Yanli; Ren, Guoyan; Yi, Junpeng; Niu, Leilei; Li, Juan

    2013-06-04

    This study aimed to investigate the effects of Cu2+, Cr2+ and Pb2+ stress on Nostoc flagelliforme cell. The response of Nostoc flagelliforme cell was analyzed under the stress. The modified BG11 culture medium containing different heavy metal ions of 0, 0.1, 1.0, 10, 100 mg/L was used to cultivate Nostoc flagelliforme cell at 25 degrees C and light intensity of 80 micromol/(m x s). Electrolyte leakage, the activities of superoxide dismutase, the content of malondialdehyde, proline, soluble protein and trehalose were analyzed. Under 1 - 100 mg/L Cu2+, Cr2+ and Pb2+ stress, electrolyte leakage and malondialdehyde contents in Nostoc flagelliforme cell were higher than those in the control group during heavy metal ions stress. Meanwhile, superoxide dismutase activity increased slightly under 10 mg/L, but was lower afterwards. The contents of proline, soluble protein and trehalose increased under 10 mg/L heavy metal ions stress, while declined under extreme heavy metal ions stress (100 mg/L). Nostoc flagelliforme cell has resistance to low heavy metal ions stress, but is damaged badly under extreme heavy metal ions stress.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. Carrier providers or killers: The case of Cu defects in CdTe

    Science.gov (United States)

    Yang, Ji-Hui; Metzger, Wyatt K.; Wei, Su-Huai

    2017-07-01

    Defects play important roles in semiconductors for optoelectronic applications. Common intuition is that defects with shallow levels act as carrier providers and defects with deep levels are carrier killers. Here, taking the Cu defects in CdTe as an example, we show that relatively shallow defects can play both roles. Using first-principles calculation methods combined with thermodynamic simulations, we study the dialectic effects of Cu-related defects on hole density and lifetime in bulk CdTe. Because CuCd can form a relatively shallow acceptor, we find that increased Cu incorporation into CdTe indeed can help achieve high hole density; however, too much Cu can cause significant non-radiative recombination. We discuss strategies to balance the contradictory effects of Cu defects based on the calculated impact of Cd chemical potential, copper defect concentrations, and annealing temperature on lifetime and hole density. These findings advance the understanding of the potential complex defect behaviors of relatively shallow defect states in semiconductors.

  3. 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.

  4. Carrier providers or killers: The case of Cu defects in CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ji-Hui; Metzger, Wyatt K.; Wei, Su-Huai

    2017-07-24

    Defects play important roles in semiconductors for optoelectronic applications. Common intuition is that defects with shallow levels act as carrier providers and defects with deep levels are carrier killers. Here, taking the Cu defects in CdTe as an example, we show that relatively shallow defects can play both roles. Using first-principles calculation methods combined with thermodynamic simulations, we study the dialectic effects of Cu-related defects on hole density and lifetime in bulk CdTe. Because CuCd can form a relatively shallow acceptor, we find that increased Cu incorporation into CdTe indeed can help achieve high hole density; however, too much Cu can cause significant non-radiative recombination. We discuss strategies to balance the contradictory effects of Cu defects based on the calculated impact of Cd chemical potential, copper defect concentrations, and annealing temperature on lifetime and hole density. These findings advance the understanding of the potential complex defect behaviors of relatively shallow defect states in semiconductors.

  5. 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.

  6. Distribution of As, Cd, and Pb in seafood in Southern China and their oral bioavailability in mice.

    Science.gov (United States)

    Zhu, Zhi-Peng; Tong, Yong-Peng; Tang, Wei-Yang; Wu, Zheng-Xin; Wu, Zhi-Bing

    2017-02-01

    The distribution of the toxic elements As, Cd, and Pb in nine different types of seafood from Shenzhen, China, was investigated by using inductively coupled plasma mass spectrometry (ICP-MS). The results revealed that the concentrations of arsenic (As) in fish (Lutjanus erythropterus, Paralichthys olivaceus) and in bivalve (Meretrix meretrix) and cadmium (Cd) in scallop (Argopecten irradians) exceed the limits established by food safety regulations in China and EU (European Union). Furthermore, the bioavailability of As, Cd, and lead (Pb) in mice after 20-day oral ingestion of Crassostrea rivularis was investigated, and the total rate of absorption of toxic elements in samples from the liver and kidney tissues and blood was determined. The results of this in vivo trial indicated that the oral bioavailability of As, Cd, and Pb was approximately 0.33, 0.45, and 0.74%, respectively.

  7. 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.

  8. 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...

  9. 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

  10. 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.

  11. 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...

  12. 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.

  13. 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)

  14. 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.

  15. 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...

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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...

  3. Effect of Pseudomonas fluorescens RB4 and Bacillus subtilis 189 on the phytoremediation potential of Catharanthus roseus (L.) in Cu and Pb-contaminated soils.

    Science.gov (United States)

    Khan, Waheed Ullah; Ahmad, Sajid Rashid; Yasin, Nasim Ahmad; Ali, Aamir; Ahmad, Aqeel

    2017-06-03

    The remediation of heavy metal-contaminated soils has become a critical issue due to toxic effects of these metals on living organisms. The current research was conducted to study the effect of Pseudomonas fluorescens RB4 and Bacillus subtilis 189 on the growth and phytoremediation potential of Catharanthus roseus in Cu- and Pb-contaminated soils. The bacterial strains exhibited significantly higher level of water-extractable Pb and Cu in Pb, Cu, and Cu+Pb-contaminated. The P. fluorescens RB4 inoculated plants, produced 102%, 48%, and 45% higher fresh weight (FW) in soils contaminated with Cu, Pb, and both elements, respectively, as compared to un-inoculated control plants. Similarly, B. subtilis 189 inoculated plants produced 108%, 43%, and 114% more FW in the presence of Cu, Pb, and both elements. The plants co-cultivated with both bacteria exhibited 121%, 102%, and 177% higher FW, in Cu, Pb, and both elements contaminated soils, as compared to respective un-inoculated control. Co-cultivation of P. fluorescens RB4, B. subtilis 189, and P. fluorescens RB4 + B. subtilis 189 resulted in higher accumulation of Cu and Pb in shoots of the C. roseus grown in contaminated soils as compared to un-inoculated control. Bacterial treatments also improved the translocation and metal bioconcentration factors. The growth and phytoextraction capability of C. roseus was improved by inoculation of P. fluorescens RB4 and B. subtilis 189.

  4. 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.