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Sample records for cd pb zn

  1. Adsorption of Pb, Cd, Zn, Cu and Hg ions on Formaldehyde and ...

    African Journals Online (AJOL)

    Adsorption of Pb(II), Cd(II), Zn(II), Cu(II) and Hg(II) ions on formaldehyde and Pyridine modified bean husks were determined. The adsorption capacity of formaldehyde modified bean husks (mg/g) was: Pb2+, 5.01; Cd2+, 3.63; Zn2+, 2.18; Hg2+, 1.82; Cu2+, 1.58 and that of pyridine modified bean husk was: Hg2+, 6.92; Cd2+ ...

  2. Bioleaching mechanism of Zn, Pb, In, Ag, Cd and As from Pb/Zn smelting slag by autotrophic bacteria.

    Science.gov (United States)

    Wang, Jia; Huang, Qifei; Li, Ting; Xin, Baoping; Chen, Shi; Guo, Xingming; Liu, Changhao; Li, Yuping

    2015-08-15

    A few studies have focused on release of valuable/toxic metals from Pb/Zn smelting slag by heterotrophic bioleaching using expensive yeast extract as an energy source. The high leaching cost greatly limits the practical potential of the method. In this work, autotrophic bioleaching using cheap sulfur or/and pyrite as energy matter was firstly applied to tackle the smelting slag and the bioleaching mechanisms were explained. The results indicated autotrophic bioleaching can solubilize valuable/toxic metals from slag, yielding maximum extraction efficiencies of 90% for Zn, 86% for Cd and 71% for In, although the extraction efficiencies of Pb, As and Ag were poor. The bioleaching performance of Zn, Cd and Pb was independent of leaching system, and leaching mechanism was acid dissolution. A maximum efficiency of 25% for As was achieved by acid dissolution in sulfursulfur oxidizing bacteria (S-SOB), but the formation of FeAsO4 reduced extraction efficiency in mixed energy source - mixed culture (MS-MC). Combined works of acid dissolution and Fe(3+) oxidation in MS-MC was responsible for the highest extraction efficiency of 71% for In. Ag was present in the slag as refractory AgPb4(AsO4)3 and AgFe2S3, so extraction did not occur. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    African Journals Online (AJOL)

    ADOWIE PERE

    Zn, Pb, Cr and Cd concentrations in fish, water and sediment from the Azuabie Creek,. Port Harcourt. ... Heavy metal contamination in the aquatic ... Azuabie Creek and the associated water ..... Public in Tianjin, China via Consumption of.

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

    Science.gov (United States)

    Gusiatin, Zygmunt Mariusz; Kulikowska, Dorota

    2016-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-05-15

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

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

    International Nuclear Information System (INIS)

    Wang Fayuan; Lin Xiangui; Yin Rui

    2007-01-01

    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. - Co-application of microbial inocula and chitosan enhanced heavy metal phytoextraction by E. splendens

  7. Heavy metals (Cd, Pb, Cu, Zn) in mudfish and sediments from three ...

    African Journals Online (AJOL)

    driniev

    2004-04-02

    Apr 2, 2004 ... and analysed for Cd and Pb by electro-thermal AAS, and for Cu and Zn by flame AAS. ... measurements and the dolomitic hard water and high pH of the Mooi River water .... Copper and zinc were determined by flame analysis at 324.8 nm ... were placed separately in clean 20 ml glass vials and one ml de-.

  8. Determination of field-based sorption isotherms for Cd, Cu, Pb and Zn in Dutch soils

    NARCIS (Netherlands)

    Otte JG; Grinsven JJM van; Peijnenburg WJGM; Tiktak A; LBG; ECO

    1999-01-01

    Sorption isotherms for metals in soil obtained in the laboratory generally underpredict the observed metal content in the solid phase in the field. Isotherms based on in-situ data are therefore required. The aim of this study is to obtain field-based sorption isotherms for Cd, Cu, Pb and Zn as input

  9. Environmental pollution study by Hg, Pb, Cd, and Zn in Chetumal bay, Quintana Roo, Mexico

    International Nuclear Information System (INIS)

    Diaz Lopez, Cristina; Carrion Jimenez, Jose; Gonzales Bucio, Jose

    2006-01-01

    The environmental pollution by heavy metals in Chetumal Bay was studied, quantifying mercury, lead, cadmium and zinc concentrations in mussels tissue (Mytilopsis sallei) and sea sediments by collecting samples in two seasons of the year (drought and rainy). Moreover, determining the motion of Cd, Pb and Zn in sediments using a BCR's sequential extraction scheme and identifying the different mineral phases by X-ray diffraction. From this study, it was observed that the Pb, Cd and Zn concentrations were lower in mussels than sediments. However the concentrations profiles for these metals are similar in mussels and sediments. Statistical correlations from the results are presented and discussed. The results obtained are in good agreement with published values for polluted sediments

  10. Atmospheric Deposition of Pb, Zn, Cu, and Cd in Amman, Jordan

    International Nuclear Information System (INIS)

    Momani, K.A.; Jiries, A.G.; Jaradat, Q.M.

    1999-01-01

    Atmospheric samples were collected by high-volume air sampler and dust fall containers during the summer of 1995 at different sites in Amman City, Jordan. Heavy metal contents in settle able (dust fall) as well as in air particulates (suspended) were analyzed by graphite furnace atomic absorption spectrophotometry. The atmospheric concentrations of Zn, Cu, Pb, and Cd were 344, 170, 291, and 3.8 ng/m 3 , respectively. On the other hand, the levels of these elements in dust fall deposition were 505, 94, 74, and 3.1 μg/g, respectively. The fluxes and dry deposition velocities of these heavy metals were determined and compared with the findings of other investigators worldwide. Significant enrichment coefficients of heavy metals in dust fall were observed. The enrichment coefficients were 12.1, 6.1, 11.7, and 1.1 for Zn, Cu, Pb, and Cd, respectively

  11. An in vivo invertebrate bioassay of Pb, Zn and Cd stabilization in contaminated soil.

    Science.gov (United States)

    Udovic, Metka; Drobne, Damjana; Lestan, Domen

    2013-08-01

    The terrestrial isopod (Porcellio scaber) was used to assess the remediation efficiency of limestone and a mixture of gravel sludge and red mud as stabilizing agents of Pb, Zn and Cd in industrially polluted soil, which contains 800, 540 and 7mgkg(-1) of Pb, Zn and Cd, respectively. The aim of our study was to compare and evaluate the results of the biological and non-biological assessment of metal bioavailability after soil remediation. Results of a 14d bioaccumulation test with P. scaber showed that that Pb and Zn stabilization were more successful with gravel sludge and red mud, while Cd was better stabilized and thus less bioavailable following limestone treatment. In vivo bioaccumulation tests confirmed the results of chemical bioaccessibility, however it was more sensitive. Biotesting with isopods is a relevant approach for fast screening of bioavailability of metals in soils which includes temporal and spatial components. Bioavailability assessed by P. scaber is a more relevant and sensitive measure of metal bioavailability than chemical bioaccessibility testing in remediated industrially polluted soil. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Lethal critical body residues as measures of Cd, Pb, and Zn bioavailability and toxicity in the earthworm Eisenia fetida

    Energy Technology Data Exchange (ETDEWEB)

    Conder, J.M.; Lanno, R.P. [Oklahoma State Univ., Dept. of Zoology, Stillwater, OK (United States)

    2003-07-01

    Background. Earthworm heavy metal concentrations (critical body residues, CBRs) may be the most relevant measures of heavy metal bioavailability in soils and may be linkable to toxic effects in order to better assess soil ecotoxicity. However, as earthworms possess physiological mechanisms to secrete and/or sequester absorbed metals as toxicologically inactive forms, total earthworm metal concentrations may not relate well with toxicity. Objective. The objectives of this research were to: i) develop LD{sub 50}s (total earthworm metal concentration associated with 50% mortality) for Cd, Pb, and Zn; ii) evaluate the LD{sub 50} for Zn in a lethal Zn-smelter soil; iii) evaluate the lethal mixture toxicity of Cd, Pb, and Zn using earthworm metal concentrations and the toxic unit (TU) approach; and iv) evaluate total and fractionated earthworm concentrations as indicators of sublethal exposure. Methods. Earthworms (Eisenia fetida (Savigny)) were exposed to artificial soils spiked with Cd, Pb, Zn, and a Cd-Pb-Zn equitoxic mixture to estimate lethal CBRs and mixture toxicity. To evaluate the CBR developed for Zn, earthworms were also exposed to Zn-contaminated field soils receiving three different remediation treatments. Earthworm metal concentrations were measured using a procedure devised to isolate toxicologically active metal burdens via separation into cytosolic and pellet fractions. (orig.)

  13. 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.

  14. Pb(II), Cd(II) and Zn(II) adsorption on low grade manganese ore ...

    African Journals Online (AJOL)

    Low grade manganese ore (LMO) of Orissa containing 58.37% SiO2, 25.05% MnO2, 8.8% Al2O3, and 5.03% Fe2O3 as the main constituents was taken to study its adsorption behaviour for Pb(II), Cd(II) and Zn(II) from aqueous solutions. The XRD studies showed the crystalline phases to be quartz, ß-MnO2, d-MnO2 and ...

  15. Pb, Cd, Cu and Zn biogeochemical behaviour and biological transfer processes in the Northwestern Mediterranean

    International Nuclear Information System (INIS)

    Nicolas, E.; Marty, J.C.; Miquel, J.C.; Fowler, S.W.

    1999-01-01

    Cd, Pb, Cu and Zn concentrations were determined in planktonic organisms (Salps, copepods), their associated faecal pellets and in particles collected at 200 and 2000 m depth in sediment traps moored in the Ligurian Sea. Al and P were also measured and taken as tracers of lithogenic and biogenic components, respectively. The aim of this work was to determine the fluxes of trace metals in the Ligurian Sea and their variations with depth, and to to assess the biogeochemical behaviour of elements having, for some of them, an anthropogenic origin, by the study of biologically-mediated uptake and removal processes

  16. 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.

  17. Removal of Pb, Zn, and Cd from contaminated soil by new washing agent from plant material.

    Science.gov (United States)

    Cao, Yaru; Zhang, Shirong; Wang, Guiyin; Huang, Qinling; Li, Ting; Xu, Xiaoxun

    2017-03-01

    Soil washing is an effective approach to remove soil heavy metals, and the washing agent is generally regarded as one of the primary factors in the process, but there is still a lack of efficient and eco-friendly agents for this technique. Here, we showed that four plant washing agents-from water extracts of Coriaria nepalensis (CN), Clematis brevicaudata (CB), Pistacia weinmannifolia (PW), and Ricinus communis (RC)-could be feasible agents for the removal of soil lead (Pb), zinc (Zn), and cadmium (Cd). The metal removal efficiencies of the agents increased with their concentrations from 20 to 80 g L -1 , decreased with the increasing solution pH, and presented different trends with the reaction time increasing. CN among the four agents had the highest removal efficiencies of soil Pb (62.02%) and Zn (29.18%) but owned the relatively low Cd removal efficiencies (21.59%). The Fourier transform infrared spectroscopy showed that the abilities of plant washing agents for the removal of soil heavy metals may result from bioactive substances with specific functional groups such as -COOH, -NH 2 , and -OH. Our study provided CN as the best washing agents for the remediation of contaminated soil by heavy metals.

  18. AtHMA3, a P1B-ATPase allowing Cd/Zn/Co/Pb vacuolar storage in Arabidopsis.

    Science.gov (United States)

    Morel, Mélanie; Crouzet, Jérôme; Gravot, Antoine; Auroy, Pascaline; Leonhardt, Nathalie; Vavasseur, Alain; Richaud, Pierre

    2009-02-01

    The Arabidopsis (Arabidopsis thaliana) Heavy Metal Associated3 (AtHMA3) protein belongs to the P1B-2 subgroup of the P-type ATPase family, which is involved in heavy metal transport. In a previous study, we have shown, using heterologous expression in the yeast Saccharomyces cerevisiae, that in the presence of toxic metals, AtHMA3 was able to phenotypically complement the cadmium/lead (Cd/Pb)-hypersensitive strain ycf1 but not the zinc (Zn)-hypersensitive strain zrc1. In this study, we demonstrate that AtHMA3 in planta is located in the vacuolar membrane, with a high expression level in guard cells, hydathodes, vascular tissues, and the root apex. Confocal imaging in the presence of the Zn/Cd fluorescent probe BTC-5N revealed that AtHMA3 participates in the vacuolar storage of Cd. A T-DNA insertional mutant was found more sensitive to Zn and Cd. Conversely, ectopic overexpression of AtHMA3 improved plant tolerance to Cd, cobalt, Pb, and Zn; Cd accumulation increased by about 2- to 3-fold in plants overexpressing AtHMA3 compared with wild-type plants. Thus, AtHMA3 likely plays a role in the detoxification of biological (Zn) and nonbiological (Cd, cobalt, and Pb) heavy metals by participating in their vacuolar sequestration, an original function for a P1B-2 ATPase in a multicellular eukaryote.

  19. Distribution and evolution of Zn, Cd, and Pb in Apollo 16 regolith samples and the average U-Pb ages of the parent rocks

    Science.gov (United States)

    Cirlin, E. H.; Housley, R. M.

    1982-01-01

    The concentration of surface (low temperature site) and interior (high temperature site) Cd, Zn, and Pb in 13 Apollo 16 highland fines samples, pristine rock 65325, and mare fines sample 75081 were analyzed directly from the thermal release profiles obtained by flameless atomic absorption technique (FLAA). Cd and Zn in pristine ferroan anothosite 65325, anorthositic grains of the most mature fines 65701, and basaltic rock fragments of mare fines 75081 were almost all surface Cd and Zn indicating that most volatiles were deposited on the surfaces of vugs, vesicles and microcracks during the initial cooling process. A considerable amount of interior Cd and Zn was observed in agglutinates. This result suggests that high temperature site interior volatiles originate from entrapment during the lunar maturation processes. Interior Cd found in the most mature fines sample 65701 was only about 15% of the total Cd in the sample. Interior Pb present in Apollo 16 fines samples went up to 60%. From our Cd studies we can assume that this interior Pb in highland fines samples is largely due to the radiogenic decay which occurred after the redistribution of the volatiles took place. We obtained an average age of 4.0 b.y. for the parent rocks of Apollo 16 highland regolith from our interior Pb analyses.

  20. Study of Zn, Cd, and Pb Adsorption Using Chitin Extracted from Lobsters from Oman Sea

    Directory of Open Access Journals (Sweden)

    Alireza Sardashti

    2015-10-01

    Full Text Available Lobster shells from Konarak Port were collected in October 2002, purified, and dried for the purposes of the present study. Chitin was extracted from the shellsusing the common chemical processes of demineralization, proteinzation, and decolonization, beforepurificationwith 1% CH3COOH and 1% NaCl to obatin an extract containing 12% (w/w chitin. Chitin composition was determined using FT-IR, X-Ray powder diffraction, BET, and C.H.N.S analysis. The FT-IR spectrum of the extracted chitin was corresponded well to the Merck standard one, indicating that it is a linear polymer of N-acetyl-D- glucosamine on which metal ions can be adsorbed. Kinetic study of chitin’s reaction with Zn+2 at pH=6.75 and an ionic strength of 0.02 M indicated that adsorption equilibrium was reached within six hours of mixing. Adsorption Langmuir isotherms for a solution of Zn+2, Cd+2, and Pb+2 ions at an initial concentration of 2×10‒3 M were determined for an ionic strenght of 0.02 M, different pH levels, and at ambient temparature using the discontinued in-pot method. The maximum amounts of metal ions adsorbed on chitin at pH= 6.75 were measured to be 0.119 mol/kg for Cd+2, 0.714 mol/kg for Zn+2, and 1.630 mol/Kg for Pb+2. The overdyeing graphs, Cs= f (pH, show that the adsorption capacity of chitin is influenced by such factors as pH, reaction time, metal ion concantration, and adsorbent particle size. Thus, chitin as a non-toxic natural polymer may be highly recommended for water detoxification from heavy metal ions.

  1. Assessment of soil contamination with Cd, Pb and Zn and source identification in the area around the Huludao Zinc Plant

    International Nuclear Information System (INIS)

    Lu, C.A.; Zhang, J.F.; Jiang, H.M.; Yang, J.C.; Zhang, J.T.; Wang, J.Z.; Shan, H.X.

    2010-01-01

    The distribution characteristics of heavy metals (cadmium (Cd), lead (Pb) and zinc (Zn)) in the natural soil profiles around the Huludao Zinc Plant (HZP), an old industrial base in Northeast China, were analyzed. The pollutant source was identified using 210 Pb isotope technique to evaluate the geochemical characteristics of Pb and the historical production records of HZP. The results indicated: dust precipitation from HZP was the primary source of the pollutants. The average deposition rates of Cd, Pb and Zn were 0.33, 1.75, and 30.97 g/m 2 year, respectively at 1 km away after HZP, and 0.0048, 0.035, and 0.20 g/m 2 year, respectively at 10 km away after HZP. There is a risk of secondary pollution to the environment as well as the food chain in seriously polluted areas used for cultivation.

  2. Assessment of soil contamination with Cd, Pb and Zn and source identification in the area around the Huludao Zinc Plant

    Energy Technology Data Exchange (ETDEWEB)

    Lu, C.A.; Zhang, J.F.; Jiang, H.M. [Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences,100081 Beijing (China); Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, 100081 Beijing (China); Yang, J.C., E-mail: yangjch@263.net [Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences,100081 Beijing (China) and Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, 100081 Beijing (China); Zhang, J.T.; Wang, J.Z.; Shan, H.X. [Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, 100081 Beijing (China); Graduate School of Chinese Academy of Agricultural Sciences,100081 Beijing (China)

    2010-10-15

    The distribution characteristics of heavy metals (cadmium (Cd), lead (Pb) and zinc (Zn)) in the natural soil profiles around the Huludao Zinc Plant (HZP), an old industrial base in Northeast China, were analyzed. The pollutant source was identified using {sup 210}Pb isotope technique to evaluate the geochemical characteristics of Pb and the historical production records of HZP. The results indicated: dust precipitation from HZP was the primary source of the pollutants. The average deposition rates of Cd, Pb and Zn were 0.33, 1.75, and 30.97 g/m{sup 2} year, respectively at 1 km away after HZP, and 0.0048, 0.035, and 0.20 g/m{sup 2} year, respectively at 10 km away after HZP. There is a risk of secondary pollution to the environment as well as the food chain in seriously polluted areas used for cultivation.

  3. Heavy metal (Cu, Zn, Cd and Pb) partitioning and bioaccessibility in uncontaminated and long-term contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Lamb, Dane T.; Ming Hui; Megharaj, Mallavarapu [Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), P.O. Box 486, Salisbury, SA 5106 (Australia); Naidu, Ravi, E-mail: ravi.naidu@crccare.com [Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), P.O. Box 486, Salisbury, SA 5106 (Australia)

    2009-11-15

    We investigated the pore-water content and speciation of copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) in a range of uncontaminated and long-term contaminated soils in order to establish their potential bioaccessibility to soil biota, plants and humans. Among the samples, soil pH (0.01 M CaCl{sub 2}) ranged from 4.9 to 8.2. The total metal content of the uncontaminated soils ranged from 3.8 to 93.8 mg Cu kg{sup -1}, 10.3 to 95 mg kg{sup -1} Zn, 0.1 to 1.8 mg Cd kg{sup -1} and 5.2 to 183 mg kg{sup -1} Pb, while metal content in the contaminated soils ranged from 104 to 6841 mg Cu kg{sup -1}, 312 to 39,000 mg kg{sup -1} Zn, 6 to 302 mg Cd kg{sup -1} and 609 to 12,000 mg kg{sup -1} Pb. Our analysis of pore-water found the Cu concentrations to be much higher in contaminated soils than in uncontaminated soils, with the distribution coefficients (K{sub d}) correlating significantly with the log of dissolved organic carbon concentrations. Despite the high total metal content of the contaminated soil, Zn, Cd and Pb were not generally found at elevated levels in the pore-water with the exception of a single contaminated soil. A long period of ageing and soil weathering may have led to a substantial reduction in heavy metal concentrations in the pore-water of contaminated soils. On the other hand, Pb bioaccessibility was found to be comparatively high in Pb contaminated soils, where it tended to exceed the total Pb values by more than 80%. We conclude that, despite the extensive ageing of some contaminated soils, the bioaccessibility of Pb remains relatively high.

  4. Heavy metal (Cu, Zn, Cd and Pb) partitioning and bioaccessibility in uncontaminated and long-term contaminated soils

    International Nuclear Information System (INIS)

    Lamb, Dane T.; Ming Hui; Megharaj, Mallavarapu; Naidu, Ravi

    2009-01-01

    We investigated the pore-water content and speciation of copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) in a range of uncontaminated and long-term contaminated soils in order to establish their potential bioaccessibility to soil biota, plants and humans. Among the samples, soil pH (0.01 M CaCl 2 ) ranged from 4.9 to 8.2. The total metal content of the uncontaminated soils ranged from 3.8 to 93.8 mg Cu kg -1 , 10.3 to 95 mg kg -1 Zn, 0.1 to 1.8 mg Cd kg -1 and 5.2 to 183 mg kg -1 Pb, while metal content in the contaminated soils ranged from 104 to 6841 mg Cu kg -1 , 312 to 39,000 mg kg -1 Zn, 6 to 302 mg Cd kg -1 and 609 to 12,000 mg kg -1 Pb. Our analysis of pore-water found the Cu concentrations to be much higher in contaminated soils than in uncontaminated soils, with the distribution coefficients (K d ) correlating significantly with the log of dissolved organic carbon concentrations. Despite the high total metal content of the contaminated soil, Zn, Cd and Pb were not generally found at elevated levels in the pore-water with the exception of a single contaminated soil. A long period of ageing and soil weathering may have led to a substantial reduction in heavy metal concentrations in the pore-water of contaminated soils. On the other hand, Pb bioaccessibility was found to be comparatively high in Pb contaminated soils, where it tended to exceed the total Pb values by more than 80%. We conclude that, despite the extensive ageing of some contaminated soils, the bioaccessibility of Pb remains relatively high.

  5. 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

  6. Using electrocoagulation for metal and chelant separation from washing solution after EDTA leaching of Pb, Zn and Cd contaminated soil.

    Science.gov (United States)

    Pociecha, Maja; Lestan, Domen

    2010-02-15

    Electrocoagulation with an Al sacrificial anode was tested for the separation of chelant and heavy metals from a washing solution obtained after leaching Pb (3200 mg kg(-1)), Zn (1100 mg kg(-1)), and Cd (21 mg kg(-1)) contaminated soil with EDTA. In the electrochemical process, the sacrificial anode corroded to release Al(3+) which served as coagulant for precipitation of chelant and metals. A constant current density of 16-128 mAc m(-2) applied between the Al anode and the stainless-steel cathode removed up to 95% Pb, 68% Zn and 66% Cd from the soil washing solution. Approximately half of the initial EDTA remained in the washing solution after treatment, up to 16.3% of the EDTA was adsorbed on Al coagulant and precipitated, the rest of the EDTA was degraded by anodic oxidation. In a separate laboratory-scale remediation experiment, we leached a soil with 40 mmol EDTA per kg of soil and reused the washing solution (after electrocoagulation) in a closed loop. It removed 53% of Pb, 26% of Zn and 52% of Cd from the soil. The discharge solution was clear and colourless, with pH 7.52 and 170 mg L(-1) Pb, 50 mg L(-1) Zn, 1.5 mg L(-1) Cd and 11 mM EDTA.

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

    International Nuclear Information System (INIS)

    Souza, Vivianne L.B. de; Nascimento, Rizia K. do; Paiva, Ana Claudia de; Silva, Josenilda M. da; Melo, Jessica V. de

    2013-01-01

    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)

  8. 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)

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

    Science.gov (United States)

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

    2008-06-15

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

  10. Effect of Applying Chemical Fertilizers on Concentration of Cd, Pb and Zn in Agricultural Soils

    Directory of Open Access Journals (Sweden)

    Hossein Pourmoghadas

    2017-03-01

    Full Text Available Background &Objective:  Nowadays uncontrolled uses of chemical fertilizers which have many heavy metals such as Cadmium, Lead and Zinc in addition have economic problems, cause to serious damages in the environment. Therefore uncontrolled application of fertilizers can cause accumulation contaminants in soil, water sources and increasing in plants and human & animals’ food chain. The main objective of this research was to investigate the effects of chemical fertilizers application to increase heavy metals in agricultural soils at directions to prevent contamination in water sources, agricultural products and the best uses of chemical fertilizers. Methods: In this study, 20 soil samples and 5 useful chemical fertilizer samples were collected and investigated. After fertilizer and soil samples were prepared, digested and filtered, heavy metals were determined with using atomic absorption. Results: The results of this study showed that, Cd in Diammonum phosphate  fertilizer 1.25 times, Super phosphate triple 1.7 times and in Macro granular fertilizer 1.5 times were as much as maximum acceptable concentration in chemical fertilizers. Cadmium concentration in all of the Jarghoye (Isfahan agricultural soil samples 3 to 7 times and in the Mobarake village (Najaf abad agricultural soil samples 10 to 35 times were as much as maximum acceptable concentration in agricultural soils. But Pb and Zn concentration in all of the agricultural soil samples was less than the amount of maximum acceptable concentration. Conclusion: Phosphate chemical fertilizers were positive effects to increase concentration of Pb and Zn in agricultural soils. Therefore, application of the fertilizer must be more attention because of increasing heavy metals in the agriculture soils and probably increasing heavy metals in food chain.  

  11. Distribution of As, Cd, Pb, and Zn in redox features of mine-waste impacted wetland soils

    Energy Technology Data Exchange (ETDEWEB)

    Strawn, Daniel G.; Hickey, Patrick J.; McDaniel, Paul A.; Baker, Leslie L. [Idaho Univ., Moscow (United States). Soil and Land Resources Div.

    2012-08-15

    Purpose: Wetland soils of the Coeur d'Alene (CdA) River Basin of northern Idaho, USA are contaminated with toxic elements released during mining activities. In this paper, we report results from a multi-scale investigation of total As, Cd, Pb, and Zn distributions along a transect of these contaminated soils. Materials and methods: Four sites along an 80-m transect were established at the Black Rock Slough wetland in CdA River Basin. The elevation difference between the upslope and lowland site was 1.1 m. Soils were sampled from three depths, down to 45 cm. Redoximorphic features were isolated from the soils and categorized into five types of cemented particles, and Fe-enriched and depleted soil masses. Soils and isolated soil separates were analyzed for total elemental concentration. Results and discussion: Within soil profiles, contaminants are enriched in surface horizons as compared to the original depositional profiles. Enrichment was more dramatic in the upland sites than the lowland sites. Fe-enriched masses that ranged in size from a few millimeters to several centimeters were also enriched in As, Pb, and Zn. At the smallest scale investigated, five different soil aggregate types ranging in size from 1 to 2 mm in diameter had distinct contaminant associations: Fe-cemented aggregates were elevated in As and Zn; Mn-cemented aggregates had more than five times as much Pb as the bulk soil; root channels were elevated in As; and charcoal particles were elevated in all contaminants, particularly Pb and Cd. Conclusions: Results show that in wetland soils pedogenic processes differentially distribute contaminants amongst the redoximorphic features. The distribution is affected by landscape position and water table influence. At the pedon scale, there is an enrichment of As, Cd, Pb, and Zn in surface horizons, suggesting that upward flux of contaminants is occurring. This contaminant redistribution should be considered in design of management and remediation

  12. Population health risk via dietary exposure to trace elements (Cu, Zn, Pb, Cd, Hg, and As) in Qiqihar, Northeastern China.

    Science.gov (United States)

    Luo, Jinming; Meng, Jia; Ye, Yajie; Wang, Yongjie; Bai, Lin

    2018-02-01

    The estimated daily intakes (EDIs) of six trace elements (Cu, Zn, Pb, Cd, Hg, and As) in vegetables (leafy vegetable, i.e., bok choy, fruit vegetables, i.e., cucumber and tomato, and other categories, i.e., mushroom, kidney bean, and potato), cereals (rice and wheat flour), and meats (pork, mutton, and beef) most commonly consumed by adult inhabitants of Qiqihar, Northeastern China, were determined to assess the health status of local people. The average EDIs of Cu, Zn, Pb, Cd, Hg, and As were with 20.77 μg (kg bw) -1 day -1 of Cu, 288 μg (kg bw) -1 day -1 of Zn, 2.01 μg (kg bw) -1 day -1 of Pb, 0.41 μg (kg bw) -1 day -1 of Cd, 0.01 μg (kg bw) -1 day -1 of Hg, and 0.52 μg (kg bw) -1 day -1 of As, respectively, which are below the daily allowance recommended by FAO/WHO. However, the maximum EDIs of Pb and Cd were 4.56 μg (kg bw) -1 day -1 and 1.68 μg (kg bw) -1 day -1 , respectively, which are above the recommended levels [i.e., 3.58 μg (kg bw) -1 day -1 for Pb and 1.0 μg (kg bw) -1 day -1 for Cd] by FAO/WHO. This finding indicates that the potential health risk induced by daily ingestion of Pb and Cd for the local residents should receive a significant concern. Similarly, we detected elevated Pb and Cd concentrations, i.e., with average of 13.58 and 0.60 mg kg -1 dw, respectively, in the adult scalp hairs. Consumption of rice, potato, bok choy, and wheat flour contributed to 75 and 82% of Pb and Cd daily intake from foodstuffs. Nevertheless, human scalp hair is inappropriate biological material for determination of the nutritional status of trace elements in this region.

  13. Copper separation using modified active carbon before the polarographic determination of Pb, Cd, Ni, Zn and Fe in wastes

    International Nuclear Information System (INIS)

    Rubel, S.; Lada, Z.M.; Golimowski, J.

    1977-01-01

    The investigations on the selective separation of Pb 2+ , Cd 2+ , Ni 2+ , Zn 2+ and Fe 3+ ions from the excess of copper were carried out. For this purpose active carbon modified by Na-diethyldithiocarbamate was used. The manner of DDTK-Na deposition on active carbon has been elaborated. The influence of pH was investigated and it was found that at pH 1(HNO 3 ) copper ions are quantitavely bound on modified carbon whereas other ions (Pb 2+ , Cd 2+ , Ni 2+ , Zn 2+ and Fe 3+ ) remain in the solution and can be determined polarographically. The elaborated method was applied to the determination of mentioned ions in the samples of wastes containing even 100-fold excess of copper. The concentration of copper can not exceed 100 mg/dm 3 . (author)

  14. Cd, Pb, and Zn mobility and (bio)availability in contaminated soils from a former smelting site amended with biochar.

    Science.gov (United States)

    Lomaglio, Tonia; Hattab-Hambli, Nour; Miard, Florie; Lebrun, Manhattan; Nandillon, Romain; Trupiano, Dalila; Scippa, Gabriella Stefania; Gauthier, Arnaud; Motelica-Heino, Mikael; Bourgerie, Sylvain; Morabito, Domenico

    2017-07-20

    Biochar is a potential candidate for the remediation of metal(loid)-contaminated soils. However, the mechanisms of contaminant-biochar retention and release depend on the amount of soil contaminants and physicochemical characteristics, as well as the durability of the biochar contaminant complex, which may be related to the pyrolysis process parameters. The objective of the present study was to evaluate, in a former contaminated smelting site, the impact of two doses of wood biochar (2 and 5% w/w) on metal immobilization and/or phytoavailability and their effectiveness in promoting plant growth in mesocosm experiments. Different soil mixtures were investigated. The main physicochemical parameters and the Cd, Pb, and Zn contents were determined in soil and in soil pore water. Additionally, the growth, dry weight, and metal concentrations were analyzed in the different dwarf bean plant (Phaseolus vulgaris L.) organs tested. Results showed that the addition of biochar at two doses (2 and 5%) improved soil conditions by increasing soil pH, electrical conductivity, and water holding capacity. Furthermore, the application of biochar (5%) to metal-contaminated soil reduced Cd, Pb, and Zn mobility and availability, and hence their accumulation in the different P. vulgaris L. organs. In conclusion, the data clearly demonstrated that biochar application can be effectively used for Cd, Pb, and Zn immobilization, thereby reducing their bioavailability and phytotoxicity.

  15. Eisenia fetida avoidance behavior as a tool for assessing the efficiency of remediation of Pb, Zn and Cd polluted soil

    International Nuclear Information System (INIS)

    Udovic, Metka; Lestan, Domen

    2010-01-01

    Remediation by means of soil leaching with ethylenediaminetetraacetic acid (EDTA) is capable of extracting the most labile soil fractions, leaving the residual metals in biologically non-available forms. We evaluated the feasibility of the standardized earthworm (Eisenia fetida) avoidance test for assessing the efficiency of soil remediation of Pb, Zn and Cd polluted soil. Chemical extraction tests (six-step sequential extraction, toxicity characteristic leaching procedure, physiologically based extraction test, diethylenediaminepentaacetic acid extraction) indicated that the mobility, oral bioaccessibility and phytoavailability of Pb, Zn and Cd were consistently reduced. However, the avoidance test showed no significant avoidance of polluted soil in favor of that which had been remediated. Pb, Zn and Cd accumulation in E. fetida mirrored the decreasing pattern of metal potential bioavailability gained by leaching the soil with increasing EDTA concentrations. The calculated bioaccumulation factors indicated the possibility of underestimating the metal bioavailability in soil using chemical extraction tests. - Tests with indicator organisms should be used for a more meaningful and holistic assessment of metal biological availability in polluted and remediated soil.

  16. Eisenia fetida avoidance behavior as a tool for assessing the efficiency of remediation of Pb, Zn and Cd polluted soil

    Energy Technology Data Exchange (ETDEWEB)

    Udovic, Metka [Centre for Soil and Environmental Science, Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, Sl-1000 Ljubljana (Slovenia); Lestan, Domen, E-mail: domen.lestan@bf.uni-lj.s [Centre for Soil and Environmental Science, Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, Sl-1000 Ljubljana (Slovenia)

    2010-08-15

    Remediation by means of soil leaching with ethylenediaminetetraacetic acid (EDTA) is capable of extracting the most labile soil fractions, leaving the residual metals in biologically non-available forms. We evaluated the feasibility of the standardized earthworm (Eisenia fetida) avoidance test for assessing the efficiency of soil remediation of Pb, Zn and Cd polluted soil. Chemical extraction tests (six-step sequential extraction, toxicity characteristic leaching procedure, physiologically based extraction test, diethylenediaminepentaacetic acid extraction) indicated that the mobility, oral bioaccessibility and phytoavailability of Pb, Zn and Cd were consistently reduced. However, the avoidance test showed no significant avoidance of polluted soil in favor of that which had been remediated. Pb, Zn and Cd accumulation in E. fetida mirrored the decreasing pattern of metal potential bioavailability gained by leaching the soil with increasing EDTA concentrations. The calculated bioaccumulation factors indicated the possibility of underestimating the metal bioavailability in soil using chemical extraction tests. - Tests with indicator organisms should be used for a more meaningful and holistic assessment of metal biological availability in polluted and remediated soil.

  17. Application of atomic absorption spectrophotometry to determine Cd, Cu, Pb, Zn,...in vegetable samples in Dalat

    Energy Technology Data Exchange (ETDEWEB)

    Giang, Nguyen; Tam, Nguyen Thanh; Ngoc Trinh, Le Thi; Mai, Truong Phuong; Minh, Nguyen Van [Nuclear Research Institute, Dalat (Viet Nam)

    2004-08-01

    Nowadays atomic absorption spectrometry has become valuable method for trace element analysis because high specificity; low detection litmus, easy to use; easy sample preparation, low investment and running costs... atomic absorption spectrometry is generally accepted as one the most suitable method for single - element analysis of trace elements in various kinds of materiel. In 2003, we applied flame - atomic absorption spectrometry for analyzing Ca, Cd, Cu, Pb, Zn...in vegetables and their extracted juices were collected form 11 locations of Dalat, including two kinds of vegetables (goods and safety) in both the summer and winter. Average concentration of Ca = 240 mg/kg wet, Cd = 0.035 mg/kg wet, Cu = 0.67 mg/kg wet, Mg = 131 mg/kg wet, Fe = 8.1/kg wet, Mn = 3.1/kg wet, Na = 3266 mg/kg wet, Pb = 0.345 mg/kg wet and Zn = 3.3 mg wet. In their extracted juices: Ca = 89 mg/kg wet, Cd = 0.008 mg/kg wet, Cu = 0.19 mg/kg wet, Mg = 43 mg/kg wet, Fe = 2.3 mg/kg wet, Mn = 0.61 mg/kg wet, Na = 971 mg/kg wet, Pb = 0.107 mg/kg wet and Zn = 0.65 mg/kg wet. (author)

  18. Application of atomic absorption spectrophotometry to determine Cd, Cu, Pb, Zn,...in vegetable samples in Dalat

    International Nuclear Information System (INIS)

    Nguyen Giang; Nguyen Thanh Tam; Le Thi Ngoc Trinh; Truong Phuong Mai; Nguyen Van Minh

    2004-01-01

    Nowadays atomic absorption spectrometry has become valuable method for trace element analysis because high specificity; low detection litmus, easy to use; easy sample preparation, low investment and running costs... atomic absorption spectrometry is generally accepted as one the most suitable method for single - element analysis of trace elements in various kinds of materiel. In 2003, we applied flame - atomic absorption spectrometry for analyzing Ca, Cd, Cu, Pb, Zn...in vegetables and their extracted juices were collected form 11 locations of Dalat, including two kinds of vegetables (goods and safety) in both the summer and winter. Average concentration of Ca = 240 mg/kg wet, Cd = 0.035 mg/kg wet, Cu = 0.67 mg/kg wet, Mg = 131 mg/kg wet, Fe = 8.1/kg wet, Mn = 3.1/kg wet, Na = 3266 mg/kg wet, Pb = 0.345 mg/kg wet and Zn = 3.3 mg wet. In their extracted juices: Ca = 89 mg/kg wet, Cd = 0.008 mg/kg wet, Cu = 0.19 mg/kg wet, Mg = 43 mg/kg wet, Fe = 2.3 mg/kg wet, Mn = 0.61 mg/kg wet, Na = 971 mg/kg wet, Pb = 0.107 mg/kg wet and Zn = 0.65 mg/kg wet. (author)

  19. Lead, Zn, and Cd in slags, stream sediments, and soils in an abandoned Zn smelting region, southwest of China, and Pb and S isotopes as source tracers

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yuangen; Li, Sun; Bi, Xiangyang; Wu, Pan; Liu, Taozhe; Li, Feili; Liu, Congqiang [Chinese Academy of Sciences, Guiyang City (China). Inst. of Geochemistry

    2010-12-15

    Smelting activity produced tons of slags with large quantities of highly toxic metals, resulting in contamination in adjacent soils and sediments as well. This study investigated the fractionation and sources of metals Pb, Zn, and Cd in polluted soils and sediments in a region with once prosperous Zn smelting activities in southwestern China. Soils with varying land uses were of a special concern due to their connection to the food chain. Obtained data would offer a valuable reference to the development of land-use management strategy in this region. In total, 130 soils and 22 stream sediments were sampled in the studied region. After air-dried and passed through a 2 mm sieve, soils and sediments were subjected to a three-step sequential extraction for the fractionation of Pb, Zn, and Cd. Besides, 66 slags were sampled, and acid-digested for the determination of total Pb, Zn, and Cd. Soils/sediments with extremely high Pb, Zn, and Cd concentrations were selected for observation and analysis using a scanning electron microscopy equipped with energy dispersive X-ray spectroscopy. Stable lead and sulphur isotope techniques were applied for source tracing of metals in soils and sediments. Data were pooled for analysis of variance together with a post-hoc multiple comparison procedure. High concentrations of Pb ({proportional_to}46,219 mg kg{sup -1} with medians of 846 mg kg{sup -1} in soil, 7,415 mg kg{sup -1} in sediment, and 8,543 mg kg{sup -1} in slag), Zn ({proportional_to}57, 178 mg kg{sup -1} with medians of 1,085 mg kg{sup -1} in soil, 15,678 mg kg{sup -1} in sediment, and 14,548 mg kg{sup -1} in slag), and Cd ({proportional_to}312 mg kg{sup -1} with medians of 29.6 mg kg{sup -1} in soil, 47.1 mg kg{sup -1} in sediment, and 47.9 mg kg{sup -1} in slag) were measured. Soils with no cultivation had greater concentrations of Pb (16,686 mg kg{sup -1} in median), Zn (13,587 mg kg{sup -1} in median), and Cd (44.1 mg kg{sup -1} in median) than those with cultivation. Al

  20. Enhancement of the atomic absorbance of Cr, Zn, Cd, and Pb in metal furnace atomic absorption spectrometry using absorption tubes

    Directory of Open Access Journals (Sweden)

    Yuya Koike

    2017-03-01

    Full Text Available Trace amounts of Cr, Zn, Cd, and Pb were determined by metal furnace atomic absorption spectrometry using absorption tubes. Various absorption tubes were designed as roof- and tube-types, and fixed above the metal furnace in order to extend the light path length. Aqueous standards and samples were injected in the metal furnace and atomized in a metal atomizer with an absorption tube (6 cm length, 15.5 mm diameter. The used of an absorption tube resulted in an enhancement of the atomic absorbance. The ratios of absorbance values with and without the roof- and tube-type absorption tubes were 1.33 and 1.11 for Cr; 1.42 and 1.99 for Zn; 1.66 and 1.98 for Cd; and 1.31 and 1.16 for Pb, respectively. The use of an absorption tube was effective for Zn and Cd analysis, as the absorbance values for these low boiling point metals doubled. The proposed method was successfully applied in the determination of Zn in tap water.

  1. Analytisch-chemische aspecten van de bepaling van As, Ca, Cd, Sb, Sn, Pb, Zn in MVS-filterdestruaten met ICP-MS

    NARCIS (Netherlands)

    Velde-Koerts T van der; Lesquillier AI; Ritsema R; LAC

    1995-01-01

    In dit onderzoek werd een ICP-MS-methode ontwikkeld voor de bepaling van Ca, Zn, As, Cd, Sb, Sn en Pb in filterdestruaten. De onderste analysegrens is 30 ng/l Sb, 60 ng/l Cd, 200 ng/l As, 300 ng/l Sn, 400 ng/l Pb, 4 mug/l Zn en 20 mug/l Ca ; de precisie is beter dan 7% RSD voor Ca, 4% RSD voor

  2. Can the shell of the green-lipped mussel Perna viridis from the west coast of Peninsular Malaysia be a potential biomonitoring material for Cd, Pb and Zn?

    Science.gov (United States)

    Yap, C. K.; Ismail, A.; Tan, S. G.; Abdul Rahim, I.

    2003-07-01

    The distributions of Cd, Pb and Zn in the total soft tissues and total shells of the green-lipped mussel Perna viridis were studied in field collected samples as well as from laboratory experimental samples. The results showed that Cd, Pb and Zn were readily accumulated in the whole shells. In mussels sampled from 12 locations along the west coast of Peninsular Malaysia, the ratios of the shell metals to the soft tissue metals were different at each sampling site. Nevertheless, the Cd and Pb levels in the shells were always higher than those in the soft tissues, while the Zn level was higher in the soft tissues than in the shells. In comparison with soft tissues, the degrees of variability for Pb and Cd concentrations in the shells were lower. The lower degrees of variability and significant ( Pwork showed that the pattern of depuration in the shell was not similar to that of the soft tissue although their patterns of accumulation were similar. This indicated that the depuration of heavy metals in the shell was not affected by the physiological conditions of the mussels. Although Zn could be regulated by the soft tissue, the incorporated Cd, Pb and Zn remained in the shell matrices. The present results support the use of the total shell of P. viridis as a potential biomonitoring material for long-term contamination of Cd, Pb and Zn.

  3. Dissolved trace metals (Ni, Zn, Co, Cd, Pb, Al, and Mn) around the Crozet Islands, Southern Ocean

    Science.gov (United States)

    Castrillejo, Maxi; Statham, Peter J.; Fones, Gary R.; Planquette, Hélène; Idrus, Farah; Roberts, Keiron

    2013-10-01

    A phytoplankton bloom shown to be naturally iron (Fe) induced occurs north of the Crozet Islands (Southern Ocean) every year, providing an ideal opportunity to study dissolved trace metal distributions within an island system located in a high nutrient low chlorophyll (HNLC) region. We present water column profiles of dissolved nickel (Ni), zinc (Zn), cobalt (Co), cadmium (Cd), lead (Pb), aluminium (Al), and manganese (Mn) obtained as part of the NERC CROZEX program during austral summer (2004-2005). Two stations (M3 and M1) were sampled downstream (north) of Crozet in the bloom area and near the islands, along with a control station (M2) in the HNLC zone upstream (south) of the islands. The general range found was for Ni, 4.64-6.31 nM; Zn, 1.59-7.75 nM; Co, 24-49 pM; Cd, 135-673 pM; Pb, 6-22 pM; Al, 0.13-2.15 nM; and Mn, 0.07-0.64 nM. Vertical profiles indicate little island influence to the south with values in the range of other trace metal deprived regions of the Southern Ocean. Significant removal of Ni and Cd was observed in the bloom and Zn was moderately correlated with reactive silicate (Si) indicating diatom control over the internal cycling of this metal. Higher concentrations of Zn and Cd were observed near the islands. Pb, Al, and Mn distributions also suggest small but significant atmospheric dust supply particularly in the northern region.

  4. Zn, Cd and Pb accumulation and arbuscular mycorrhizal colonisation of pennycress Thlaspi praecox Wulf. (Brassicaceae) from the vicinity of a lead mine and smelter in Slovenia

    International Nuclear Information System (INIS)

    Vogel-Mikus, Katarina; Drobne, Damjana; Regvar, Marjana

    2005-01-01

    Significant hyperaccumulation of Zn, Cd and Pb in field samples of Thlaspi praecox Wulf. collected from a heavy metal polluted area in Slovenia was found, with maximal shoot concentrations of 14590 mg kg -1 Zn, 5960 mg kg -1 Cd and 3500 mg kg -1 Pb. Shoot/root ratios of 9.6 for Zn and 5.6 for Cd show that the metals were preferentially transported to the shoots. Shoot bioaccumulation factors exceeded total soil Cd levels 75-fold and total soil Zn levels 20-fold, further supporting the hyperaccumulation of Cd and Zn. Eighty percent of Pb was retained in roots, thus indicating exclusion as a tolerance strategy for Pb. Low level colonisation with arbuscular mycorrhizal fungi (AMF) of a Paris type was observed at the polluted site, whereas at the non-polluted site Arum type colonisation was more common. To our knowledge this is the first report of Cd hyperaccumulation and AMF colonisation in metal hyperaccumulating T. praecox. - Thlaspi praecox Wulf. (Brassicaceae) is a newly discovered Cd, Zn and Pb hyperaccumulator able to form symbiosis with arbuscular mycorrhizal fungi

  5. Colonisation of a Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen with indigenous arbuscular mycorrhizal fungal mixture induces changes in heavy metal and nutrient uptake

    International Nuclear Information System (INIS)

    Vogel-Mikus, Katarina; Pongrac, Paula; Kump, Peter; Necemer, Marijan; Regvar, Marjana

    2006-01-01

    Plants of the Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen (Brassicaceae) inoculated or not with indigenous arbuscular mycorrhizal (AM) fungal mixture were grown in a highly Cd, Zn and Pb contaminated substrate in order to evaluate the functionality of symbiosis and assess the possible impact of AM colonisation on heavy metal uptake and tolerance. The results suggest AM development in the metal hyperaccumulating T. praecox is favoured at elevated nutrient demands, e.g. during the reproductive period. AM colonisation parameters positively correlated with total soil Cd and Pb. Colonised plants showed significantly improved nutrient and a decreased Cd and Zn uptake as revealed by TRXRF, thus confirming the functionality of the symbiosis. Reduced heavy metal uptake, especially at higher soil metal contents, indicates a changed metal tolerance strategy in colonised T. praecox plants. This is to our knowledge the first report on AM colonisation of the Zn, Cd and Pb hyperaccumulator T. praecox in a greenhouse experiment. - Colonisation of a Zn, Cd and Pb hyperaccumulator Thlaspi praecox with arbuscular mycorrhizal fungi resulted in improved nutrient and reduced Cd and Zn uptake

  6. Zn, Cd and Pb accumulation and arbuscular mycorrhizal colonisation of pennycress Thlaspi praecox Wulf. (Brassicaceae) from the vicinity of a lead mine and smelter in Slovenia

    Energy Technology Data Exchange (ETDEWEB)

    Vogel-Mikus, Katarina [Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia)]. E-mail: katarina.vogel@uni-lj.si; Drobne, Damjana [Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia); Regvar, Marjana [Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia)

    2005-01-01

    Significant hyperaccumulation of Zn, Cd and Pb in field samples of Thlaspi praecox Wulf. collected from a heavy metal polluted area in Slovenia was found, with maximal shoot concentrations of 14590 mg kg{sup -1} Zn, 5960 mg kg{sup -1} Cd and 3500 mg kg{sup -1} Pb. Shoot/root ratios of 9.6 for Zn and 5.6 for Cd show that the metals were preferentially transported to the shoots. Shoot bioaccumulation factors exceeded total soil Cd levels 75-fold and total soil Zn levels 20-fold, further supporting the hyperaccumulation of Cd and Zn. Eighty percent of Pb was retained in roots, thus indicating exclusion as a tolerance strategy for Pb. Low level colonisation with arbuscular mycorrhizal fungi (AMF) of a Paris type was observed at the polluted site, whereas at the non-polluted site Arum type colonisation was more common. To our knowledge this is the first report of Cd hyperaccumulation and AMF colonisation in metal hyperaccumulating T. praecox. - Thlaspi praecox Wulf. (Brassicaceae) is a newly discovered Cd, Zn and Pb hyperaccumulator able to form symbiosis with arbuscular mycorrhizal fungi.

  7. Colonisation of a Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen with indigenous arbuscular mycorrhizal fungal mixture induces changes in heavy metal and nutrient uptake

    Energy Technology Data Exchange (ETDEWEB)

    Vogel-Mikus, Katarina [Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia); Pongrac, Paula [Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia); Kump, Peter [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Necemer, Marijan [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Regvar, Marjana [Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia)]. E-mail: marjana.regvar@bf.uni-lj.si

    2006-01-15

    Plants of the Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen (Brassicaceae) inoculated or not with indigenous arbuscular mycorrhizal (AM) fungal mixture were grown in a highly Cd, Zn and Pb contaminated substrate in order to evaluate the functionality of symbiosis and assess the possible impact of AM colonisation on heavy metal uptake and tolerance. The results suggest AM development in the metal hyperaccumulating T. praecox is favoured at elevated nutrient demands, e.g. during the reproductive period. AM colonisation parameters positively correlated with total soil Cd and Pb. Colonised plants showed significantly improved nutrient and a decreased Cd and Zn uptake as revealed by TRXRF, thus confirming the functionality of the symbiosis. Reduced heavy metal uptake, especially at higher soil metal contents, indicates a changed metal tolerance strategy in colonised T. praecox plants. This is to our knowledge the first report on AM colonisation of the Zn, Cd and Pb hyperaccumulator T. praecox in a greenhouse experiment. - Colonisation of a Zn, Cd and Pb hyperaccumulator Thlaspi praecox with arbuscular mycorrhizal fungi resulted in improved nutrient and reduced Cd and Zn uptake.

  8. Heavy metals (Cd, Pb, Cu, Zn) in mudfish and sediments from three ...

    African Journals Online (AJOL)

    The percentage of uranium present in sediment samples (analysed by energy dispersive X-ray spectrometry) from the three dams was 9.0 % (SD 2.1%). In sediment it was found that cation exchange capacity measurements and the dolomitic hard water and high pH of the Mooi River water effectively \\'detoxified\\' Cd and Pb, ...

  9. Genotypic variations in the accumulation of Cd, Cu, Pb and Zn exhibited by six commonly grown vegetables

    International Nuclear Information System (INIS)

    Alexander, P.D.; Alloway, B.J.; Dourado, A.M.

    2006-01-01

    Metal contaminants in garden and allotment soils could possibly affect human health through a variety of pathways. This study focused on the potential pathway of consumption of vegetables grown on contaminated soil. Five cultivars each of six common vegetables were grown in a control and in a soil spiked with Cd, Cu, Pb and Zn. Highly significant differences in metal content were evident between cultivars of a number of vegetables for several of the contaminants. Carrot and pea cultivars exhibited significant differences in accumulated concentrations of Cd and Cu with carrot cultivars also exhibiting significant differences in Zn. Distinctive differences were also identified when comparing one vegetable to another, legumes (Leguminosae) tending to be low accumulators, root vegetables (Umbelliferae and Liliaceae) tending to be moderate accumulators and leafy vegetables (Compositae and Chenopodiaceae) being high accumulators. - Genotypic differences between cultivars of vegetable species can be important in determining the extent of accumulation of metals from contaminated soil

  10. Ecophysiological and seasonal variations in Cd, Pb, Zn, and Ni concentrations in the leaves of urban deciduous trees in Istanbul

    International Nuclear Information System (INIS)

    Baycu, Guelriz; Tolunay, Doganay; Ozden, Hakan; Guenebakan, Suereyya

    2006-01-01

    The concentrations of Cd, Pb, Zn and Ni were measured in the leaves of 7 species of deciduous trees, from the urban sites of Istanbul, in both the Spring and Autumn seasons. We detected some differences in the heavy metal concentrations of the control and urban site samples of identical species. Highest concentrations of Cd were detected in Populus, Pb in Aesculus and Robinia, Zn in Populus, and Ni in Robinia and Fraxinus. Lowest chlorophyll content and highest peroxidase (POD) activity was found in the urban site samples of Acer. We have found a positive correlation between the increase in the POD activity and the Pb concentration in Populus. Generally, the tree species investigated in this study, are considered to have different tolerance levels to heavy metal pollution. The data obtained show that the chlorophyll content and the POD activity may be used as heavy metal stress biomarkers in the urban trees. - Ecophysiological changes in the urban trees may be used as heavy metal stress biomarkers

  11. Pb-Zn-Cd-Hg multi isotopic characterization of the Loire River Basin, France

    Science.gov (United States)

    Millot, R.; Widory, D.; Innocent, C.; Guerrot, C.; Bourrain, X.; Johnson, T. M.

    2012-12-01

    The contribution of human activities such as industries, agriculture and domestic inputs, becomes more and more significant in the chemical composition (major ions and pollutants such as metals) of the dissolved load of rivers. Furthermore, this influence can also be evidenced in the suspended solid matter known to play an important role in the transport of heavy metals through river systems. Human factors act as a supplementary key process. Therefore the mass-balance for the budget of catchments and river basins include anthropogenic disturbances. The Loire River in central France is approximately 1010 km long and drains an area of 117,800 km2. Initially, the Loire upstream flows in a south to north direction originating in the Massif Central, and continues up to the city of Orléans, 650 km from the source. In the upper basin, the bedrock is old plutonic rock overlain by much younger volcanic rocks. The Loire River then follows a general east to west direction to the Atlantic Ocean. The intermediate basin includes three major tributaries flowing into the Loire River from the left bank: the Cher, the Indre and the Vienne rivers; the main stream flows westward and its valley stretches toward the Atlantic Ocean. Here, the Loire River drains the sedimentary series of the Paris Basin, mainly carbonate deposits. The lower Loire basin drains pre-Mesozoic basement of the Armorican Massif and its overlying Mesozoic to Cenozoic sedimentary deposits. The Loire River is one of the main European riverine inputs to the Atlantic ocean. Here we are reporting concentration and isotope data for heavy metals Zn-Cd-Pb-Hg in river waters and suspended sediments from the Loire River Basin. In addition, we also report concentration and isotope data for these metals for the different industrial sources within the Loire Basin, as well as data for biota samples such as mussels and oysters from the Bay of Biscay and North Brittany. These organisms are known to be natural accumulators of

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

    International Nuclear Information System (INIS)

    Rodrigues, S.M.; Cruz, N.; Coelho, C.; Henriques, B.; Carvalho, L.; Duarte, A.C.; Pereira, E.; Römkens, Paul 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 bioaccessible pool). Oral bioaccessibility in urban soils was higher than in samples from rural, industrial and mining areas which is most likely related to sources of metals and parent materials of corresponding soils. The availability and reactivity were described well by non-linear Freundlich-type equations when considering differences in soil properties. The resulting empirical models are able to predict availability and reactivity and can be used to improve the accuracy of risk assessment. Furthermore, a close 1:1 relationship exists between results from the 0.43 M HNO 3 method and the SBET method which substantially facilitates risk assessment procedures and reduces analytical costs. -- Highlights: ► Availability of PTEs in urban soils is described well by non-linear Freundlich-type equations. ► A 1:1 relationship was obtained between the 0.43 M HNO 3 method and the SBET method. ► A single soil extraction indicates reactivity and bioaccessibility of metals in soils. ► The reactive pool is suitable to assess risks of Cd, Cu, Pb and Zn in urban soils. -- A single analysis of the reactive pool by dilute nitric acid is suitable to assess risks of Cd, Cu, Pb and Zn in urban soils related to leaching to (ground)water and exposure to human beings (bioaccessibility)

  13. Essential trace (Zn, Cu, Mn and toxic (Cd, Pb, Cr elements in the liver of birds from Eastern Poland

    Directory of Open Access Journals (Sweden)

    Komosa A.

    2012-01-01

    Full Text Available We have focused our study on the concentrations of essential heavy metals (Zn, Cu and Mn and non-essential trace metals (Pb, Cd and Cr in the livers of birds from Eastern Poland. The largest mean amount of Zn - as much as 279 mg/kg dry mass (d.m. - was found in mute swans. However, only in one of the analysed buzzard specimens the concentration of Zn, found to be 664 mg/kg d.m., exceeded the level indicative of poisoning for this element. Birds specializing in catching rodents accumulated Mn in their livers in a very narrow range of concentrations, around 5.0 mg/kg d.m. on average. The range of mean Mn concentrations (around 6.5 mg/kg d.m. was also found to be narrow for piscivorous birds. The highest mean levels of Pb were found in mute swans (2.7 mg/kg d.m., and the highest levels of Cd (2.0 mg/kg d.m. for rooks. Concentrations of total Cr above detection level were found in 22 specimens (53.7%, and concentration values were highest for rooks. Analyses showed that the concentrations of biogenic elements did not exceed the levels indicative of poisoning (except in one specimen. The study demonstrated that lead shots remain a hazard to water ecosystems. Pb, Cd and Cr levels in the livers of omnivorous and piscivorous species indicate the permanent presence of these elements in the environment and may confirm the thesis about the growing role of electronic waste, including metallic e-waste, in the emission of the total amount of contamination with these elements.

  14. Stabilization of Cd-, Pb-, Cu- and Zn-contaminated calcareous agricultural soil using red mud: a field experiment.

    Science.gov (United States)

    Wang, Yangyang; Li, Fangfang; Song, Jian; Xiao, Ruiyang; Luo, Lin; Yang, Zhihui; Chai, Liyuan

    2018-04-12

    Red mud (RM) was used to remediate heavy metal-contaminated soils. Experiments with two different dosages of RM added to soils were carried out in this study. It was found that soil pH increased 0.3 and 0.5 unit with the dosage of 3 and 5% (wt%), respectively. At the dosage of 5%, the highest stabilization efficiencies for Cd, Pb, Cu and Zn reached 67.95, 64.21, 43.73 and 63.73%, respectively. The addition of RM obviously transferred Cd from the exchangeable fraction to the residual fraction. Meanwhile, in comparison with the control (no RM added), it reduced 24.38, 49.20, 19.42 and 8.89% of Cd, Pb, Cu and Zn in wheat grains at the RM addition dosage of 5%, respectively. At the same time, the yield of wheat grains increased 17.81 and 24.66% at the RM addition dosage of 3 and 5%, respectively. Finally, the addition of RM did not change the soil bacterial community. These results indicate that RM has a great potential in stabilizing heavy metals in calcareous agricultural soils.

  15. Assessing comparative terrestrial ecotoxicity of Cd, Co, Cu, Ni, Pb, and Zn: The influence of aging and emission source

    DEFF Research Database (Denmark)

    Owsianiak, Mikolaj; Holm, Peter E.; Fantke, Peter

    2015-01-01

    H or soil organic carbon, emission source occasionally has an effect on reactivity of Cd, Co, Cu, Ni, Pb and Zn emitted from various anthropogenic sources followed by aging in the soil from a few years to two centuries. The uncertainties in estimating the age prevent definitive conclusions about...... the influence of aging time on the reactivity of metals from anthropogenic sources in soils. Thus, for calculating comparative toxicity potentials of man-made metal contaminations in soils, we recommend using time-horizon independent accessibility factors derived from source-specific reactive fractions....

  16. Monitoring air pollution at Mohammedia (Morocco): Pb, Cd and Zn in the blood of pigeons (Columba livia).

    Science.gov (United States)

    Kouddane, N; Mouhir, L; Fekhaoui, M; Elabidi, A; Benaakame, R

    2016-05-01

    The concentrations of Pb, Cd and Zn were investigated in the blood of pigeons (Columba livia) in order to assess the degree of pollution by heavy metal. For this, wild city pigeons were caught at four different locations in Mohammedia classified according to their industrial activity and road traffic density. Significant difference in heavy metal concentrations were observed between sites studied, the highest lead and cadmium levels were found in industrial area and center town, while the highest zinc level was found in the less contaminated area. These results indicate that the industrial activities and the road traffic are the most important source of pollution.

  17. 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.

  18. Activated carbon and biochar from agricultural by-products in the adorption of Cd, Pb and Zn under laboratory conditions

    Science.gov (United States)

    Coscione, Aline; Zini, Barbara

    2015-04-01

    The immobilization of inorganic contaminants by using biochar in soils has played an increasingly important role and it is seen as an attractive alternative for the remediation of heavy metals. Although, the production of activated carbon (CA) from agricultural by-products has received special attention, the activation of the the organic source has been studied in order to increase its porposity, surface area and chemical polarity, resulting in higher adsorption of metals. Therefore, this study aimed to evaluate the effectiveness of BC and CA samples, obtained from a eucalyptus husks and cane sugar bagasse after activation with 20% phosphoric acid and pyrolyzed at 450oC in the retention of Zn, Cd and Pb using contaminated individual solutions. The experiment was performed using samples of activated carbon of eucalyptus husk (CCA), eucalyptus husk biochar (BC), activated carbon of sugar cane bagasse (CBA) and sugar cane bagasse biochar (BB), treated with Zn, Cd (range of tested solution from 0.1 up to 12 mmol L-1) and Pb (from 0.1 up 50 mmol L-1) and the adjustemento of Langmuir adsorption isotherms. Samples obtained from bagasse presented higher adsoprtion of the metals tested then eucalyptus. Also the activation process had not the expected effect on either eucalyptus and bagasse samples The maxmum adsorption capacyty of samples were as follws, in mmol g-1: for Cd - 0.36 for BC; 0.32 for CCA; 0.40 for BB; 0.31 for CBA. For Zn- 0.14 for BC; no adsorbed by CCA; 0.35 5 for BB; 0.06 for CBA. For Pb - 1.24 for BC; 0.40 for CCA; 0,45 for BB; 0,03 for CBA. However, it was also observed that due to the activation with phosphoric acid, the pH of the activated carbon (CCA and CBA) were 2.4 and 2.5 in comparison with the biochars not activated (BC and BB) 9.7 and 7.0 respectively. Thus, it is yet not possible to state if the calculate capacity is due exclusively to the complexation of chemical groups in the surface of samples or to which extent there is a contribution of

  19. Enriquecimiento, disponibilidad y contaminación de metales traza (Cd, Cu, Pb y Zn) en sedimentos de lagunas urbanas de Concepción-Chile Enrichment, availability and contamination of trace metals (Cd, Cu, Pb and Zn) in sediments of urban lagoons in Concepción, Chile

    OpenAIRE

    Elizabeth González Sepúlveda; María Retamal Cifuentes; Valentina Medina Pedreros; Ramón Ahumada Bermúdez; José Neira Hinojosa

    2009-01-01

    Trace metals (Cd, Cu, Pb and Zn) enrichment, availability and contamination in superficial sediments of three interconnected urban lagoons localized in Concepción-Chile, were evaluated. According to the results of geochemical fracctionation analysis, Cu and Pb are rather associated with oxi-hydroxides, Cd is associated with exchangeable and carbonates fraction, while Zn is mainly associated with organic, oxi-hydroxides and residual fraction. The estimation of the availability percentages indi...

  20. Enhanced stabilization of Pb, Zn, and Cd in contaminated soils using oxalic acid-activated phosphate rocks.

    Science.gov (United States)

    Zhang, Zhuo; Guo, Guanlin; Wang, Mei; Zhang, Jia; Wang, Zhixin; Li, Fasheng; Chen, Honghan

    2018-01-01

    Phosphate amendments, especially phosphate rock (PR), are one of the most commonly used materials to stabilize heavy metals in contaminated soils. However, most of PR reserve consists of low-grade ore, which limits the efficiency of PR for stabilizing heavy metals. This study was to enhance the stabilization of heavy metals through improving the available phosphorous (P) release of PR by oxalic acid activation. Raw PR and activated PR (APR) were characterized by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray powder diffraction (XRD), Brunauer-Emmett-Teller (BET) surface analysis, and laser diffraction to determine the changes of structure and composition of APR. The stabilization effectiveness of lead (Pb), zinc (Zn), and cadmium (Cd) in soils by APR was investigated through toxicity leaching test and speciation analysis. The results indicated that after treatment by oxalic acid, (1) the crystallinity of the fluorapatite phase of PR transformed into the weddellite phase; (2) the surface area of PR increased by 37%; (3) the particle size of PR became homogenized (20-70 μm); and (4) the available P content in PR increased by 22 times. These changes of physicochemical characteristics of PR induced that APR was more effective to transform soil heavy metals from the non-residual fraction to the residual fraction and enhance the stabilization efficiency of Pb, Zn, and Cd than PR. These results are significant for the future use of low-grade PR to stabilize heavy metals.

  1. 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.

  2. The relationships between heavy metal (Cd, Cr, Cu, Fe, Pb, Zn) levels and the size of six Mediterranean fish species

    International Nuclear Information System (INIS)

    Canli, Mustafa; Atli, Gueluezar

    2003-01-01

    Significant relationships between metal concentrations and fish size were negative. - Heavy metal (Cd, Cr, Cu, Fe, Pb, Zn) concentrations in the muscle, gill and liver of six fish species (Sparus auratus, Atherina hepsetus, Mugil cephalus, Trigla cuculus, Sardina pilchardus and Scomberesox saurus) from the northeast Mediterranean Sea were measured and the relationships between fish size (length and weight) and metal concentrations in the tissues were investigated by linear regression analysis. Metal concentrations (as μg/g d.w.) were highest in the liver, except for iron in the gill of Scomberesox saurus and lowest in the muscle of all the fish species. Highest concentrations of Cd (4.50), Cr (17.1) and Pb (41.2) were measured in liver tissues of T. cuculus, Sardina pilchardus and A. hepsetus, respectively. The liver of M. cephalus showed strikingly high Cu concentrations (202.8). The gill of Scomberesox saurus was the only tissue that showed highest (885.5) iron concentrations. Results of linear regression analysis showed that, except in a few cases, significant relationships between metal concentrations and fish size were negative. Highly significant (P<0.001) negative relationships were found between fish length and Cr concentrations in the liver of A. hepsetus and M. cephalus, and Cr concentrations in the gill of T. cuculus. Cr and Pb concentrations in the liver and Cu concentrations in all the tissues of Scomberesox saurus also showed very significant (P<0.001) negative relationships. Negative relationships found here were discussed

  3. STUDY ON PHYTO-EXTRACTION BALANCE OF ZN, CD AND PB FROM MINE-WASTE POLLUTED SOILS BY USING FESTUCA ARUNDINACEA AND LOLIUM PERENNE SPECIES

    Directory of Open Access Journals (Sweden)

    B. LIXANDRU

    2009-05-01

    Full Text Available Through the cultivation of tall fescue (Festuca arundinacea and of perennial ryegrass for two years on a chernozem type of soil, in the Banat's plain area we investigated the phyto-extraction potential of Zn, Cd and Pb. In the experimental plot it has been incorporated a quantity of 20 kg of mine-waste per square meter, in a mass ratio of 1:2,5. The mine-waste polluting "contribution" was of 1209 mg Zn / kg d.s., 4.70 mg Cd / kg d.s. and 188.2 mg Pb / kg d.s. The metals content in the soil was determined at the two moments of biomass harvesting, and through balance calculations we could establish the phyto-extraction efficiency of the two foragegrasses species. The obtained results indicate that Festuca arundinacea has an average phyto-extraction yield of 50% for Zn and Cd in the soil; in the case of an ionic excess of 3,5 to 4 times, the phyto-extraction efficiency is reduced, more obvious in the case of Pb (lead ions. The species Lolium perenne registers a yield of almost 92% in the process of phyto-extraction of Zn. The yield values for Cd si Pb are lower, but comparable with the control plot. Unlike Festuca arundinacea, the Lollium perenne species tolerates better the Cd and Pb ionic excess.

  4. Distribution of Cd, Ck, Pb and Zn in Soil and Vegetation Compartments in Stands of Five Boreal Tree Species in N.E. Sweden

    International Nuclear Information System (INIS)

    Alriksson, A.; Eriksson, H. M.

    2001-01-01

    Concentrations and total quantity of cadmium (Cd), cupper (Cu),lead (Pb) and zink (Zn) were determined in biomass and soil compartments in a replicated tree species experiment with 27-yr-old stands growing on former farmland in N.E. Sweden. Sequential extractions of soil samples were performed in order to estimate the exchangeable and an organically bound fraction of each element. The tree species included were Picea abies (L.)H. Karst., Pinus sylvestris L., Pinus contorta Dougl., Larix sibirica Ledeb., and Betula pendula Roth.Tree species influenced the rate of removal of Cu, Pb and Zn in case of stemwood harvesting, and of Cd, Cu and Zn in the case of whole-tree harvesting. B. pendula and P. abies had higher quantities and average concentrations of Zn in the biomass. For all species, >50% of the Zn in the stems was found in the bark. P. abies and L. sibirica had higher quantities of Cu in the biomass than the other species.P. abies and P. contorta had high quantities of Cd in the biomass in relation to the other species. Branches and stembark contained high concentrations of Cd and Pb in relation to foliage and stemwood. Dead branches had especially high concentrations of Pb. The high accumulation rate of Zn in the biomass of B. pendula was related to a low exchangeable amount of Zn in the A horizon. In the superficial centimeters of the A horizon, a depletion similar to that found for Zn was detected for Cu, whereas for Cd and Pb, no correlations were found between quantities of elements in the trees and element pools in the soil

  5. 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

    International Nuclear Information System (INIS)

    Komjarova, I.; Blust, R.

    2009-01-01

    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 2.5 mM. The uptake of Zn and Pb was significantly suppressed only at 2.5 mM 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 (2-8 mM Na + for Cd and 8 mM 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 (2 mM 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.

  6. Soil Cd, Cr, Cu, Ni, Pb and Zn sorption and retention models using SVM: Variable selection and competitive model.

    Science.gov (United States)

    González Costa, J J; Reigosa, M J; Matías, J M; Covelo, E F

    2017-09-01

    The aim of this study was to model the sorption and retention of Cd, Cu, Ni, Pb and Zn in soils. To that extent, the sorption and retention of these metals were studied and the soil characterization was performed separately. Multiple stepwise regression was used to produce multivariate models with linear techniques and with support vector machines, all of which included 15 explanatory variables characterizing soils. When the R-squared values are represented, two different groups are noticed. Cr, Cu and Pb sorption and retention show a higher R-squared; the most explanatory variables being humified organic matter, Al oxides and, in some cases, cation-exchange capacity (CEC). The other group of metals (Cd, Ni and Zn) shows a lower R-squared, and clays are the most explanatory variables, including a percentage of vermiculite and slime. In some cases, quartz, plagioclase or hematite percentages also show some explanatory capacity. Support Vector Machine (SVM) regression shows that the different models are not as regular as in multiple regression in terms of number of variables, the regression for nickel adsorption being the one with the highest number of variables in its optimal model. On the other hand, there are cases where the most explanatory variables are the same for two metals, as it happens with Cd and Cr adsorption. A similar adsorption mechanism is thus postulated. These patterns of the introduction of variables in the model allow us to create explainability sequences. Those which are the most similar to the selectivity sequences obtained by Covelo (2005) are Mn oxides in multiple regression and change capacity in SVM. Among all the variables, the only one that is explanatory for all the metals after applying the maximum parsimony principle is the percentage of sand in the retention process. In the competitive model arising from the aforementioned sequences, the most intense competitiveness for the adsorption and retention of different metals appears between

  7. 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.

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

    International Nuclear Information System (INIS)

    Nedeltcheva, T.; Atanassova, M.; Dimitrov, J.; Stanislavova, L.

    2005-01-01

    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

  9. Equilibrium and kinetic studies of Pb(II, Cd(II and Zn(II sorption by Lagenaria vulgaris shell

    Directory of Open Access Journals (Sweden)

    Mitić-Stojanović Dragana-Linda

    2012-01-01

    Full Text Available The sorption of lead, cadmium and zinc ions from aqueous solution by Lagenaria vulgaris shell biosorbent (LVB in batch system was investigated. The effect of relevant parameters such as contact time, biosorbent dosage and initial metal ions concentration was evaluated. The Pb(II, Cd(II and Zn(II sorption equilibrium (when 98% of initial metal ions were sorbed was attained within 15, 20 and 25 min, respectively. The pseudo first, pseudo-second order, Chrastil’s and intra-particle diffusion models were used to describe the kinetic data. The experimental data fitted the pseudo-second order kinetic model and intra-particle diffusion model. Removal efficiency of lead(II, cadmium(II and zinc(II ions rapidly increased with increasing biosorbent dose from 0.5 to 8.0 g dm-3. Optimal biosorbent dose was set to 4.0 g dm-3. An increase in the initial metal concentration increases the sorption capacity. The sorption data of investigated metal ions are fitted to Langmuir, Freundlich and Temkin isotherm models. Langmuir model best fitted the equilibrium data (r2 > 0.99. Maximal sorption capacities of LVB for Pb(II, Cd(II and Zn(II at 25.0±0.5°C were 0.130, 0.103 and 0.098 mM g-1, respectively. The desorption experiments showed that the LVB could be reused for six cycles with a minimum loss of the initial sorption capacity.

  10. CORRELATION OF THE PARTITIONING OF DISSOLVED ORGANIC MATTER FRACTIONS WITH THE DESORPTION OF CD, CU, NI, PB AND ZN FROM 18 DUTCH SOILS

    Science.gov (United States)

    Eighteen Dutch soils were extracted in aqueous solutions at varying pH. Extracts were analyzed for Cd, Cu, Ni, Pb and Zn by ICP-AES. Extract dissolved organic carbon (DOC) was also concentrated onto a macroreticular resin and fractionation into three operationally defined fract...

  11. Voltametrické stanovení Cu, Pb, Cd, Zn a Tl pomocí stříbrné pevné amalgamové elektrody

    Czech Academy of Sciences Publication Activity Database

    Josypčuk, Bohdan; Novotný, Ladislav

    2002-01-01

    Roč. 96, č. 9 (2002), s. 756-760 ISSN 0009-2770 Institutional research plan: CEZ:AV0Z4040901 Keywords : silver solid amalgam electrodes * voltammetry * Cu, Pb, Cd, Zn, Tl Subject RIV: CG - Electrochemistry Impact factor: 0.336, year: 2002

  12. An inter-laboratory study to test the ability of amendments to reduce the availability of Cd, Pb, and Zn in situ

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Sally [Box 352100 University of Washington, Seattle, WA 98195 (United States)]. E-mail: slb@u.washington.edu; Christensen, Barbara [Box 352100 University of Washington, Seattle, WA 98195 (United States); Lombi, Enzo [CSIRO Land and Water PMB, 2 Glen Osmond, Adelaide, South Australia (Australia)]. E-mail: enzo.lombi@csiro.au; McLaughlin, Mike [CSIRO Land and Water PMB, 2 Glen Osmond, Adelaide, South Australia (Australia)]. E-mail: mike.mclaughlin@csiro.au; McGrath, Steve [Rothamsted Research, Harpenden, Herts AL5 2JQ (United Kingdom)]. E-mail: steve.mcgrath@bbsrc.ac.uk; Colpaert, Jan [Limburgs Universitair, Centrum Universitaire Campus, Building D, BE 3590 Diepenbeek (Belgium); Vangronsveld, Jaco [Limburgs Universitair, Centrum Universitaire Campus, Building D, BE 3590 Diepenbeek (Belgium)]. E-mail: jvangron@luc.ac.be

    2005-11-15

    An international inter-laboratory research program investigated the effectiveness of in situ remediation of soils contaminated by cadmium, lead and zinc, measuring changes in soil and soil solution chemistry, plants and soil microbiota. A common soil, from mine wastes in Jasper County MO, was used. The soil was pH 5.9, had low organic matter (1.2 g kg{sup -1} C) and total Cd, Pb, and Zn concentrations of 92, 5022, and 18 532 mg kg{sup -1}, respectively. Amendments included lime, phosphorus (P), red mud (RM), cyclonic ashes (CA), biosolids (BIO), and water treatment residuals (WTR). Both soil solution and NH{sub 4}NO{sub 3} extractable metals were decreased by all treatments. Phytotoxicity of metals was reduced, with plants grown in P treatments having the highest yields and lowest metal concentration (0.5, 7.2 and 406 mg kg{sup -1} Cd, Pb, and Zn). Response of soil micro-organisms was similar to plant responses. Phosphorus addition reduced the physiologically based extraction test Pb from 84% of total Pb extracted in the untreated soil to 34.1%. - Addition of phosphorus to Pb, Zn and Cd contaminated mine waste was able to reduce metal toxicity for a range of biological endpoints.

  13. An inter-laboratory study to test the ability of amendments to reduce the availability of Cd, Pb, and Zn in situ

    International Nuclear Information System (INIS)

    Brown, Sally; Christensen, Barbara; Lombi, Enzo; McLaughlin, Mike; McGrath, Steve; Colpaert, Jan; Vangronsveld, Jaco

    2005-01-01

    An international inter-laboratory research program investigated the effectiveness of in situ remediation of soils contaminated by cadmium, lead and zinc, measuring changes in soil and soil solution chemistry, plants and soil microbiota. A common soil, from mine wastes in Jasper County MO, was used. The soil was pH 5.9, had low organic matter (1.2 g kg -1 C) and total Cd, Pb, and Zn concentrations of 92, 5022, and 18 532 mg kg -1 , respectively. Amendments included lime, phosphorus (P), red mud (RM), cyclonic ashes (CA), biosolids (BIO), and water treatment residuals (WTR). Both soil solution and NH 4 NO 3 extractable metals were decreased by all treatments. Phytotoxicity of metals was reduced, with plants grown in P treatments having the highest yields and lowest metal concentration (0.5, 7.2 and 406 mg kg -1 Cd, Pb, and Zn). Response of soil micro-organisms was similar to plant responses. Phosphorus addition reduced the physiologically based extraction test Pb from 84% of total Pb extracted in the untreated soil to 34.1%. - Addition of phosphorus to Pb, Zn and Cd contaminated mine waste was able to reduce metal toxicity for a range of biological endpoints

  14. Wood-derived-biochar combined with compost or iron grit for in situ stabilization of Cd, Pb, and Zn in a contaminated soil.

    Science.gov (United States)

    Oustriere, Nadège; Marchand, Lilian; Rosette, Gabriel; Friesl-Hanl, Wolfgang; Mench, Michel

    2017-03-01

    In situ stabilization of Cd, Pb, and Zn in an Austrian agricultural soil contaminated by atmospheric depositions from a smelter plant was assessed with a pine bark chip-derived biochar, alone and in combination with either compost or iron grit. Biochar amendment was also trialed in an uncontaminated soil to detect any detrimental effect. The pot experiment consisted in ten soil treatments (% w/w): untreated contaminated soil (Unt); Unt soil amended with biochar alone (1%: B1; 2.5%: B2.5) and in combination: B1 and B2.5 + 5% compost (B1C and B2.5C), B1 and B2.5 + 1% iron grit (B1Z and B2.5Z); uncontaminated soil (Ctrl); Ctrl soil amended with 1 or 2.5% biochar (CtrlB1, CtrlB2.5). After a 3-month reaction period, the soil pore water (SPW) was sampled in potted soils and dwarf beans were grown for a 2-week period. The SPW Cd, Pb, and Zn concentrations decreased in all amended-contaminated soils. The biochar effects increased with its addition rate and its combination with either compost or iron grit. Shoot Cd and Zn removals by beans were reduced and shoot Cd, Pb, and Zn concentrations decreased to common values in all amended soils except the B1 soil. Decreases in the SPW Cd/Pb/Zn concentrations did not improve the root and shoot yields of plants as compared to the Ctrl soil.

  15. Geographical and pedological drivers of distribution and risks to soil fauna of seven metals (Cd, Cu, Cr, Ni, Pb, V and Zn) in British soils.

    Science.gov (United States)

    Spurgeon, David J; Rowland, Philip; Ainsworth, Gillian; Rothery, Peter; Long, Sara; Black, Helaina I J

    2008-05-01

    Concentrations of seven metals were measured in over 1000 samples as part of an integrated survey. Sixteen metal pairs were significantly positively correlated. Cluster analysis identified two clusters. Metals from the largest (Cr, Cu, Ni, V, Zn), but not the smallest (Cd, Pb) cluster were significantly negatively correlated with spatial location and soil pH and organic matter content. Cd and Pb were not correlated with these parameters, due possibly to the masking effect of recent extensive release. Analysis of trends with soil properties in different habitats indicated that general trends may not necessarily be applicable to all areas. A risk assessment indicated that Zn poses the most widespread direct risk to soil fauna and Cd the least. Any risks associated with high metal concentrations are, however, likely to be greatest in habitats such as arable and horticultural, improved grassland and built up areas where soil metal concentrations are more frequently elevated.

  16. 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.

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

    International Nuclear Information System (INIS)

    Raimundo, J.; Vale, C.; Duarte, R.; Moura, I.

    2008-01-01

    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

  18. 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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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. -- Highlights: ► Agricultural soils contain higher metal concentrations than non-agricultural soils. ► The site located in the factory district has the highest metal concentration. ► Cu, Zn and Cd are dominated by residual fraction, and Pb by reducible fraction. ► Cd pollution should not be overlooked in soils upstream of Pearl River. -- The mobility of four investigated metals is low but Cd pollution should not be overlooked in soils upstream of Pearl River

  19. Immobilization of Pb, Cd, and Zn in a contaminated soil using eggshell and banana stem amendments: metal leachability and a sequential extraction study.

    Science.gov (United States)

    Ashrafi, Mehrnaz; Mohamad, Sharifah; Yusoff, Ismail; Shahul Hamid, Fauziah

    2015-01-01

    Heavy-metal-contaminated soil is one of the major environmental pollution issues all over the world. In this study, two low-cost amendments, inorganic eggshell and organic banana stem, were applied to slightly alkaline soil for the purpose of in situ immobilization of Pb, Cd, and Zn. The artificially metal-contaminated soil was treated with 5% eggshell or 10% banana stem. To simulate the rainfall conditions, a metal leaching experiment for a period of 12 weeks was designed, and the total concentrations of the metals in the leachates were determined every 2 weeks. The results from the metal leaching analysis revealed that eggshell amendment generally reduced the concentrations of Pb, Cd, and Zn in the leachates, whereas banana stem amendment was effective only on the reduction of Cd concentration in the leachates. A sequential extraction analysis was carried out at the end of the experiment to find out the speciation of the heavy metals in the amended soils. Eggshell amendment notably decreased mobility of Pb, Cd, and Zn in the soil by transforming their readily available forms to less accessible fractions. Banana stem amendment also reduced exchangeable form of Cd and increased its residual form in the soil.

  20. Toxic Metals (Pb and Cd and Their Respective Antagonists (Ca and Zn in Infant Formulas and Milk Marketed in Brasilia, Brazil

    Directory of Open Access Journals (Sweden)

    José G. Dórea

    2010-11-01

    Full Text Available In non-ideal scenarios involving partial or non-breastfeeding, cow’s milk-based dairy products are mainstream in infant feeding. Therefore, it is important to study the concentrations of potentially neurotoxic contaminants (Pb and Cd and their respective counteracting elements (Ca and Zn in infant dairy products. Fifty-five brands of infant formulas and milk sold in Brasilia, Brazil were analyzed. The dairy products came from areas in the central-west (26%, southeast (29% and south of Brazil (36% extending as far as Argentina (7% and the Netherlands (2%. For toxic Pb and Cd, median concentrations in powdered samples were 0.109 mg/kg and 0.033 mg/kg, respectively; in fluid samples median Pb concentration was 0.084 mg/kg, but median Cd concentration was below the limit of detection and overall values were below reference safety levels. However, 62% of these samples presented higher Pb concentration values than those established by FAO/WHO. Although the inverse correlation between Cd and Zn (Spearman r = −0.116; P = 0.590 was not statistically significant, the positive correlation between Ca and Pb was (Spearman r = 0.619; P < 0.0001. Additionally, there was a significant correlation between Pb and Cd. Furthermore, the study also revealed that provision of the essential trace element Zn in infant formulas can provide adequate amounts of the recommended daily requirements. Infant formulas and milk sold for consumption by infants and children can be an efficient tool to monitor neurotoxic metal risk exposure among young children.

  1. STUDY ON PHYTOEXTRACTION BALANCE OF ZN, CD, PB FROM MINE-WASTE POLLUTED SOILS BY USING MEDICAGO SATIVA AND TRIFOLIUM PRATENSE SPECIES

    Directory of Open Access Journals (Sweden)

    B. LIXANDRU

    2009-05-01

    Full Text Available For a term of two years was studied phytoextractive potential of Zn, Cd and Pb using successive culture of alfalfa (Medicago sativa and red clover (Trifolium pratense. In the experimental plot was incorporated a quantity of 20 kg mine waste per square meter, providing in soil 1209 mg Zn/kg d.s., 4.70 mg Cd/kg d.s. and 188.2 mg Pb/kg d.s. The metals content accumulated in plants was determined at the two moments of biomass harvesting, and through balance calculations we could establish the phytoextraction efficiency of the two forage-grasses species. The obtained results indicate that both perennial forage-legumes species have a good phytoextractive capacity and tolerance for Zn and Pb, especially Trifolium pratense specie. By using this species as phytoextractors on soil polluted with 3.76 times more Pb and 4.03 times more Zn, is provided the reduction of metallic ions concentration in soil to limits admitted by laws in a period of 3, respectively, 4 years.

  2. Retention efficiency of Cd, Pb and Zn from agricultural by-products activated carbon and biochar under laboratory conditions

    Science.gov (United States)

    Coscione, Aline; Ramos, Barbara

    2015-04-01

    The immobilization of inorganic contaminants by using biochar in soils has played an increasingly important role and it is seen as an attractive alternative for the remediation of heavy metals. Although, the production of activated carbon (CA) from agricultural by-products has received special attention, the activation of the the organic source has been studied in order to increase its porposity, surface area and chemical polarity, resulting in higher adsorption of metals. Therefore, this study aimed to evaluate the effectiveness of BC and CA samples, obtained from a eucalyptus husks and cane sugar bagasse after activation with 20% phosphoric acid and pyrolyzed at 450oC in the retention of Zn, Cd and Pb using contaminated individual solutions. The experiment was performed using samples of activated carbon of eucalyptus husk (CCA), eucalyptus husk biochar (BC), activated carbon of sugar cane bagasse (CBA) and sugar cane bagasse biochar (BB) previously treated with Zn, Cd (range of tested solution from 0.1 up to 12 mmol L-1) and Pb (from 0.1 up 50 mmol L-1) which were submitted to stirring with ammonium acetate solution at pH 4.9 for 48 h. The results obtained were adjusted with Langmuir desorptiom isotherms. The pH of the resulting solution, were the meatls were analyse, was measure and remained in the range 4.9 - 5.0. The lower pH found in activated samples (range 2.4-2.5) resulted in larger desorption of metals than the biochar samples (pH of 9.7 for BC and 7.0 for BB). This result is surprising since for the biochar samples it was expected that any precipated metals were dissolved by the desorption solution in addition to metals released by ion exchange. Although the desorption results of activated samoels is still unclear, hich we belive may be explaibed by some adicitonal insterumental analysis, biochar samples showed better potential for application in contaminated soils than the previous.

  3. Highly enhanced photocurrent of novel quantum-dot-co-sensitized PbS-Hg/CdS/Cu:ZnO thin films for photoelectrochemical applications

    International Nuclear Information System (INIS)

    Gohel, Jignasa V.; Jana, A.K.; Singh, Mohit

    2017-01-01

    A novel quantum-dot-co-sensitized PbS-Hg/CdS/Cu:ZnO thin films synthesized by low-cost process. The properties of ZnO are also enhanced by doping and co-doping. It is also compared with quantum-dot co-sensitization. Optical properties, crystal structure, morphology, and photocurrent are characterized by UV-Vis spectroscopy, XRD, SEM, and solar simulator, respectively. The bandgap is interestingly reduced highly to 2.6 eV for Ag co-doped Cu:ZnO. It is unprecedentedly reduced to 2.1 eV and even 1.97 eV for CdS and PbS-Hg QD-sensitized thin films, respectively. An exceptionally enhanced photocurrent of 17.1 mA/cm"2 is achieved with PbS-Hg-co-sensitized CdS-sensitized Cu:ZnO thin film. This is an excellent achievement, which highly supports the potential of low-cost solar conversion. (orig.)

  4. Highly enhanced photocurrent of novel quantum-dot-co-sensitized PbS-Hg/CdS/Cu:ZnO thin films for photoelectrochemical applications

    Energy Technology Data Exchange (ETDEWEB)

    Gohel, Jignasa V.; Jana, A.K.; Singh, Mohit [Sardar Vallabhbhai National Institute of Technology, Chemical Engineering Department, Surat, Gujarat (India)

    2017-08-15

    A novel quantum-dot-co-sensitized PbS-Hg/CdS/Cu:ZnO thin films synthesized by low-cost process. The properties of ZnO are also enhanced by doping and co-doping. It is also compared with quantum-dot co-sensitization. Optical properties, crystal structure, morphology, and photocurrent are characterized by UV-Vis spectroscopy, XRD, SEM, and solar simulator, respectively. The bandgap is interestingly reduced highly to 2.6 eV for Ag co-doped Cu:ZnO. It is unprecedentedly reduced to 2.1 eV and even 1.97 eV for CdS and PbS-Hg QD-sensitized thin films, respectively. An exceptionally enhanced photocurrent of 17.1 mA/cm{sup 2} is achieved with PbS-Hg-co-sensitized CdS-sensitized Cu:ZnO thin film. This is an excellent achievement, which highly supports the potential of low-cost solar conversion. (orig.)

  5. An Assessment of the Accumulation Potential of Pb, Zn and Cd by Avicennia marina (Forssk. Vierh. in Vamleshwar Mangroves, Gujarat, India

    Directory of Open Access Journals (Sweden)

    Isaiah Nirmal KUMAR

    2011-03-01

    Full Text Available The study deals with the accumulation of Pb, Zn and Cd in an important mangrove species, Avicennia marina (Forssk. Vierh., in the Vamleshwar mangrove ecosystem, near Narmada estuary, West coast of Gujarat, India with height differences of 0.5, 1.5, 2.5 meters and carried out under field conditions during October, 2009. The site was located on 21�30�11.55�� N latitude and 72�43�53.68�� E longitude. Mangrove receives heavy metal pollution from upstream areas of Narmada estuary and highly populated settlements. However, little is known about the capacity of mangrove plants to take up and store heavy metals in them. Water, sediment and plant parts such as roots, stems and leaves were analyzed for finding the trace metal accumulation of different height groups by Inductive Coupled Plasma Analyser (ICPA. Amount of the content of metals found in the water, sediment and plant parts were in the order of Pb>Zn>Cd. The average contents of heavy metals in the waters were 57.83 mg l-1 for Pb, 3.89 83 mg l-1 for Zn and 0.42 mg l-1 for Cd. It was observed that the average contents of Pb (73.6 mg l-1, Zn (8.1 mg l-1 and Cd (0.73 mg l-1 in the sediments were below the critical soil concentrations. The concentrations of heavy metals in different parts of Avicennia marina were in the order Roots>stem>leaf except for Cd, but Cd found higher in leaf. The ranges of the content of heavy metals in plants were 18.5-102.2 mg l-1 for Pb, 3.5-19.5 mg l-1 for Zn and 0.2-4.1 mg l-1 for Cd. The concentrations of all heavy metals in Avicennia marina except Pb were falling within the normal range and were much more in the plants have the highest height. The present study has shown the potential of Avicennia marina as a phytoremediation species for selected heavy metals in many mangrove ecosystems.

  6. An Assessment of the Accumulation Potential of Pb, Zn and Cd by Avicennia marina (Forssk. Vierh. in Vamleshwar Mangroves, Gujarat, India

    Directory of Open Access Journals (Sweden)

    Isaiah Nirmal KUMAR

    2011-03-01

    Full Text Available The study deals with the accumulation of Pb, Zn and Cd in an important mangrove species, Avicennia marina (Forssk. Vierh., in the Vamleshwar mangrove ecosystem, near Narmada estuary, West coast of Gujarat, India with height differences of 0.5, 1.5, 2.5 meters and carried out under field conditions during October, 2009. The site was located on 213011.55 N latitude and 724353.68 E longitude. Mangrove receives heavy metal pollution from upstream areas of Narmada estuary and highly populated settlements. However, little is known about the capacity of mangrove plants to take up and store heavy metals in them. Water, sediment and plant parts such as roots, stems and leaves were analyzed for finding the trace metal accumulation of different height groups by Inductive Coupled Plasma Analyser (ICPA. Amount of the content of metals found in the water, sediment and plant parts were in the order of Pb>Zn>Cd. The average contents of heavy metals in the waters were 57.83 mg l-1 for Pb, 3.89 83 mg l-1 for Zn and 0.42 mg l-1 for Cd. It was observed that the average contents of Pb (73.6 mg l-1, Zn (8.1 mg l-1 and Cd (0.73 mg l-1 in the sediments were below the critical soil concentrations. The concentrations of heavy metals in different parts of Avicennia marina were in the order Roots>stem>leaf except for Cd, but Cd found higher in leaf. The ranges of the content of heavy metals in plants were 18.5-102.2 mg l-1 for Pb, 3.5-19.5 mg l-1 for Zn and 0.2-4.1 mg l-1 for Cd. The concentrations of all heavy metals in Avicennia marina except Pb were falling within the normal range and were much more in the plants have the highest height. The present study has shown the potential of Avicennia marina as a phytoremediation species for selected heavy metals in many mangrove ecosystems.

  7. 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

    to the added concentrations, with Pb always showing the lowest levels. Stirred flow chamber experiments showed strong hysteresis for Pb and Cu, sorption being mostly irreversible. The differences affecting the studied heavy metals are mainly due to different affinity for the adsorption sites. Pine bark can......The objective of this work was to determine the retention of five metals on pine bark using stirred flow and batch-type experiments. Resulting from batch-type kinetic experiments, adsorption was rapid, with no significant differences for the various contact times. Adsorption was between 98 and 99...

  8. The transfer and fate of Pb from sewage sludge amended soil in a multi-trophic food chain: a comparison with the labile elements Cd and Zn.

    Science.gov (United States)

    Dar, Mudasir Irfan; Khan, Fareed Ahmad; Green, Iain D; Naikoo, Mohd Irfan

    2015-10-01

    The contamination of agroecosystems due to the presence of trace elements in commonly used agricultural materials is a serious issue. The most contaminated material is usually sewage sludge, and the sustainable use of this material within agriculture is a major concern. This study addresses a key issue in this respect, the fate of trace metals applied to soil in food chains. The work particularly addresses the transfer of Pb, which is an understudied element in this respect, and compares the transfer of Pb with two of the most labile metals, Cd and Zn. The transfer of these elements was determined from sludge-amended soils in a food chain consisting of Indian mustard (Brassica juncea), the mustard aphid (Lipaphis erysimi) and a predatory beetle (Coccinella septempunctata). The soil was amended with sludge at rates of 0, 5, 10 and 20 % (w/w). Results showed that Cd was readily transferred through the food chain until the predator trophic level. Zn was the most readily transferred element in the lower trophic levels, but transfer to aphids was effectively restricted by the plant regulating shoot concentration. Pb had the lowest level of transfer from soil to shoot and exhibited particular retention in the roots. Nevertheless, Pb concentrations were significantly increased by sludge amendment in aphids, and Pb was increasingly transferred to ladybirds as levels increased. The potential for Pb to cause secondary toxicity to organisms in higher trophic levels may have therefore been underestimated.

  9. Pollution of soils (Pb, Cd, Cr, Zn, Cu, Ni) along the ring road of Wrocław (Poland)

    Science.gov (United States)

    Hołtra, Anna; Zamorska-Wojdyła, Dorota

    2017-11-01

    The concentrations of metallic pollution in soils and plants along the ring road of Wrocław, Poland, have been determined. Environmental samples were collected from the surface layer of the profile within 2-3 m from the edge of the road. The analysis of metals (Pb, Cd, Cr, Zn, Cu and Ni) has been carried out through FAAS and GFAAS methods. The mineralizates of soils and plants were prepared in HNO3, 65% supra pure, using the Microwave Digestion System. The pH and conductivity of the soil solutions were measured to evaluate their active and exchangeable acidity and the salinity of the soils. The index of the enrichment of soils in metals (Wn) and the bioaccumulation coefficient (WB) have been determined. Also, histograms of the frequency of the occurrence of metals in the environmental samples and the Pearson's correlation coefficients were presented. The results of metal concentrations in soils were compared to the geochemical background in uncontaminated soils of Poland. The assessment of the results in the soils was also made relative to the standard, according to the Polish Ministry of Environment Regulation from September 1st, 2016. During the assessment of the bioaccumulation coefficients of metals in plants a reference was made to the content of undesirable substances in feed in agreement with the Polish Ministry of Agriculture and Rural Development Regulation from January 23rd, 2007.

  10. Assessing comparative terrestrial ecotoxicity of Cd, Co, Cu, Ni, Pb, and Zn: The influence of aging and emission source

    International Nuclear Information System (INIS)

    Owsianiak, Mikołaj; Holm, Peter E.; Fantke, Peter; Christiansen, Karen S.; Borggaard, Ole K.; Hauschild, Michael Z.

    2015-01-01

    Metal exposure to terrestrial organisms is influenced by the reactivity of the solid-phase metal pool. This reactivity is thought to depend on the type of emission source, on aging mechanisms that are active in the soil, and on ambient conditions. Our work shows, that when controlling for soil pH or soil organic carbon, emission source occasionally has an effect on reactivity of Cd, Co, Cu, Ni, Pb and Zn emitted from various anthropogenic sources followed by aging in the soil from a few years to two centuries. The uncertainties in estimating the age prevent definitive conclusions about the influence of aging time on the reactivity of metals from anthropogenic sources in soils. Thus, for calculating comparative toxicity potentials of man-made metal contaminations in soils, we recommend using time-horizon independent accessibility factors derived from source-specific reactive fractions. - Highlights: • We found an effect of source on reactivity of anthropogenic metals in soils. • The influence of aging on reactivity of anthropogenic metals was not consistent. • We recommend including source and disregarding aging in calculation of CTPs values. - Improving current life cycle inventory (LCI) and life cycle impact assessment (LCIA) practice in terrestrial ecotoxicity assessment of metals.

  11. Trace analysis of Cd, Cu, Pb and Zn in various materials using differential pulse anodic stripping voltammetry

    International Nuclear Information System (INIS)

    Ahmed, R.; Viqar-un-Nisa; Tanwir, R.

    1988-09-01

    Sampling and sample preparation methods have been described. Digestion methods for different types of materials and acid purification systems have been developed. For trace analysis purposes cleaning methods for glassware etc. have been described. Differential pulse anodic stripping voltametric (DPASV) method has been worked out for the trace analysis of zn, cd, pb and Cu in different types of materials. Linearity of the method has been checked by drawing concentration versus currents (peak height) curves. Precision of the method has been checked by analysing a number of actual samples. of the method has been verified by analysing standards of U.S.A. Comparative studies have been done between Differential pulse anodic stripping voltammetric method and Atomic Absorption spectroscopic method. Problems of contamination and systematic errors during trace and ultra-trace analysis have been discussed. A variety of samples including soil, spinach, wheat flour, rice flour, dry milk, coriander, kidney stones, bladder stones etc. have been analysed and preliminary results have been reported. (author)

  12. Proficiency test Plant 6 - determination of As, Cd, Cu, Hg, Pb, Se and Zn in dry mushroom powder (Suillus bovinus)

    International Nuclear Information System (INIS)

    Polkowska-Motrenko, H.; Dudek, J.; Chajduk, E.; Sypula, M.; Sadowska-Bratek, M.

    2006-01-01

    Proficiency testing scheme PLANT 6: Determination of As, Cd, Cu, Hg, Pb, Se and Zn in dry mushroom powder (Suillus bovinus) has been described. The proficiency test has been provided by the Institute of Nuclear Chemistry and Technology (Warsaw) with cooperation with POLLAB-CHEM/EURACHEM-PL and REFMAT Society. Wild mushrooms were collected in the forest in north-west Poland, cleaned, i.e. dust, soil and attached mosses were removed. Mushrooms were cut into smaller parts and air dried in a dryer. Dried mushrooms were milled in a centrifugal mill and sieved. Particles of fraction below 1 mm diameter were collected. Analytical samples of 20 g mass were prepared. The material were then characterized by homogeneity testing and determination of assigned values for concentration of elements in question. The testing samples were sent to the laboratories participating in the proficiency test. The results supplied by the participants were statistically evaluated and the calculated values of z-score and En numbers were used for the evaluation of the participating laboratory competency. (author)

  13. Dynamic modelling of atmospherically-deposited Ni, Cu, Zn, Cd and Pb in Pennine catchments (northern England)

    International Nuclear Information System (INIS)

    Tipping, E.; Rothwell, J.J.; Shotbolt, L.; Lawlor, A.J.

    2010-01-01

    Simulation modelling with CHUM-AM was carried out to investigate the accumulation and release of atmospherically-deposited heavy metals (Ni, Cu, Zn, Cd and Pb) in six moorland catchments, five with organic-rich soils, one with calcareous brown earths, in the Pennine chain of northern England. The model considers two soil layers and a third layer of weathering mineral matter, and operates on a yearly timestep, driven by deposition scenarios covering the period 1400-2010. The principal processes controlling heavy metals are competitive solid-solution partitioning of solutes, chemical interactions in solution, and chemical weathering. Agreement between observed and simulated soil metal pools and surface water concentrations for recent years was generally satisfactory, the results confirming that most contemporary soil metal is from atmospheric pollution. Metals in catchments with organic-rich soils show some mobility, especially under more acid conditions, but the calcareous mineral soils have retained nearly all anthropogenic metal inputs. Complexation by dissolved organic matter and co-transport accounts for up to 80% of the Cu in surface waters. - CHUM-AM is applied to six differing moorland catchments to account for the accumulation and leaching of atmospherically-deposited trace metals over the past several centuries.

  14. Dynamic modelling of atmospherically-deposited Ni, Cu, Zn, Cd and Pb in Pennine catchments (northern England)

    Energy Technology Data Exchange (ETDEWEB)

    Tipping, E., E-mail: et@ceh.ac.u [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom); Rothwell, J.J. [Upland Environments Research Unit, School of Environment and Development, University of Manchester, Manchester M13 9PL (United Kingdom); Shotbolt, L. [Geography Department, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Lawlor, A.J. [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)

    2010-05-15

    Simulation modelling with CHUM-AM was carried out to investigate the accumulation and release of atmospherically-deposited heavy metals (Ni, Cu, Zn, Cd and Pb) in six moorland catchments, five with organic-rich soils, one with calcareous brown earths, in the Pennine chain of northern England. The model considers two soil layers and a third layer of weathering mineral matter, and operates on a yearly timestep, driven by deposition scenarios covering the period 1400-2010. The principal processes controlling heavy metals are competitive solid-solution partitioning of solutes, chemical interactions in solution, and chemical weathering. Agreement between observed and simulated soil metal pools and surface water concentrations for recent years was generally satisfactory, the results confirming that most contemporary soil metal is from atmospheric pollution. Metals in catchments with organic-rich soils show some mobility, especially under more acid conditions, but the calcareous mineral soils have retained nearly all anthropogenic metal inputs. Complexation by dissolved organic matter and co-transport accounts for up to 80% of the Cu in surface waters. - CHUM-AM is applied to six differing moorland catchments to account for the accumulation and leaching of atmospherically-deposited trace metals over the past several centuries.

  15. Heavy metal (Pb, Cu, Zn and Cd content in wine produced from grape cultivar Mavrud, grown in an industrially polluted region

    Directory of Open Access Journals (Sweden)

    Violina Angelova

    1999-09-01

    Full Text Available The investigation was carried out in the period 1991-1993 with cv. Mavrud, grown in the region with a major industrial pollutant the Non-Ferrous-Metal Works (NFMW and a region with no industrial pollutants (as a control. The heavy metal content in soil, grapes and wine was determined. Most of the heavy metals in the grapes precipitate during fermentation into the sediments, which is the reason for their significantly lower content in the wine. Water washing of grape before processing leads to about 2 time decrease in the Pb, Cu, Zn and Cd contents of wine. The pre-washing of grapes does not lead to any quality deterioration in the wine produced. The amounts of Cu, Zn and Cd in the wine from cv. Mavrud, grown in the region of the NFMW-Plovdiv, are lower than the maximum admissible levels, while the Pb content exceeds them about two times.

  16. Influence of thermal treatment on bentonite used as adsorbent for Cd, Pb, Zn retention from mono-solute and poly-solute aqueous solutions

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    Susana Yamila Martinez Stagnaro

    2012-08-01

    Full Text Available The retentions of Zn, Cd and Pb cations by one treated bentonite up to 750 °C were analyzed. The retentions were evaluated by using mono-and poly-solute aqueous solutions of such cations. The adsorptions were carried out in batch system at room temperature. The solid/liquid ratio was 2% wt.v-1. The solids were characterized by X-ray diffraction, thermal and chemical analyses. The Zn cation from mono- or polysolute-solutions was retained in higher amount than Cd and Pb cations in similar solution types by bentonite. The retentions were effective up to 450 °C calcined bentonite, after that, the retention capacity decreased in concordance with dehydroxylation of the structure of clay minerals.

  17. Distribution of heavy metals (Pb, Cd, and Zn) in sediment profiles associated to Rhizophora mangle in Sevilla River - Cienaga Grande de Santa Marta, Colombia

    International Nuclear Information System (INIS)

    Parra, Juan Pablo; Espinosa, Luisa Fernanda

    2008-01-01

    In order to evaluate the vertical distribution of the heavy metals Pb, Cd, and Zn in sediments associated to Rhizophora mangle plants, potentially bioavailable and not bioavailable concentrations of these metals were determined in three sediment cores collected in the Sevilla River, Cienaga Grande de Santa Marta. Measurements were carried out by inductively coupled plasma-atomic emission spectrometry. The results showed that in Sevilla River mangrove ecosystem these metals are accumulated principally in non-bioavailable forms, this means that a great part or them are retained in the sediment. The retention of Pb, Cd, and Zn in the sediments of this mangrove ecosystem is strongly related to the physicochemical parameters pH, salinity, and redox potential, and to organic matter, and silt and clays contents

  18. 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.

  19. A test of the stability of Cd, Cu, Hg, Pb and Zn profiles over two decades in lake sediments near the Flin Flon Smelter, Manitoba, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Percival, J.B.; Outridge, P.M., E-mail: outridge@nrcan.gc.ca

    2013-06-01

    Lake sediments are valuable archives of atmospheric metal deposition, but the stability of some element profiles may possibly be affected by diagenetic changes over time. In this extensive case study, the stability of sedimentary Cd, Cu, Hg, Pb and Zn profiles was assessed in dated sediment cores that were collected in 2004 from four smelter-affected lakes near Flin Flon, Manitoba, which had previously been cored in 1985. Metal profiles determined in 1985 were in most cases clearly reproduced in the corresponding sediment layers in 2004, although small-scale spatial heterogeneity in metal distribution complicated the temporal comparisons. Pre-smelter (i.e. pre-1930) increases in metal profiles were likely the result of long-range atmospheric metal pollution, coupled with particle mixing at the 1930s sediment surface. However, the close agreement between key inflection points in the metal profiles sampled two decades apart suggests that metals in most of the lakes, and Hg and Zn in the most contaminated lake (Meridian), were stable once the sediments were buried below the surface mixed layer. Cadmium, Cu and Pb profiles in Meridian Lake did not agree as well between studies, showing evidence of upward remobilization over time. Profiles of redox-indicator elements (Fe, Mn, Mo and U) suggested that the rate of Mn oxyhydroxide recycling within sediment was more rapid in Meridian Lake, which may have caused the Cd, Cu and Pb redistribution. - Highlights: • Sedimentary Cd, Cu, Hg, Pb and Zn profiles in four lakes were mostly unchanged over 19 years. • In one lake, Cd, Cu and Pb profiles were offset relative to the originals. • The offset could indicate diagenetic upcore dispersal of these metals.

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

    Directory of Open Access Journals (Sweden)

    P. Licata

    2010-01-01

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

  1. Slash-and-char: An ancient agricultural technique holds new promise for management of soils contaminated by Cd, Pb and Zn

    International Nuclear Information System (INIS)

    Niu, Li-qin; Jia, Pu; Li, Shao-peng; Kuang, Jia-liang; He, Xiao-xin; Zhou, Wen-hua; Liao, Bin; Shu, Wen-sheng; Li, Jin-tian

    2015-01-01

    Heavy metal contamination of agricultural soils is of worldwide concern. Unfortunately, there are currently no efficient and sustainable approaches for addressing this concern. In this study, we conducted a field experiment in which an agricultural soil highly contaminated by cadmium (Cd), lead (Pb) and zinc (Zn) was treated on-site by an ancient agricultural technique, ‘slash-and-char’, that was able to convert the biomass feedstock (rice straw) into biochar in only one day. We found evidence that in comparison to the untreated soil, the treated soil was associated with decreased bioavailability of the heavy metals and increased vegetable yields. Most importantly, the treatment was also coupled with dramatic reductions in concentrations of the heavy metals in vegetables, which made it possible to produce safe crops in this highly contaminated soil. Collectively, our results support the idea that slash-and-char offers new promise for management of soils contaminated by Cd, Pb and Zn. - Highlights: • We explored the potential of slash-and-char in dealing with soil metal pollution. • Metal bioavailability in the soil treated with slash-and-char was reduced by 24–65%. • Vegetable yield in the soil treated with slash-and-char was increased by 34–67%. • Slash-and-char could reduce the metal concentration in vegetables to a safe level. - An ancient agricultural technique called ‘slash-and-char’ offers new promise for management of soils contaminated multiply by Cd, Pb and Zn

  2. Determination of Cd, Pb, Zn and Cu in Sediment Compartments by Sequential Extraction and Isotope Dilution Inductively Coupled Plasma Mass Spectrometry (ID-ICP-MS

    Directory of Open Access Journals (Sweden)

    Gardolinski Paulo C. F. C.

    2002-01-01

    Full Text Available Trace concentrations of Cd, Cu, Pb and Zn in four different sediment fractions extracted in sequence were determined by isotope dilution inductively coupled mass spectrometry (IDICPMS. The metals from each fraction were extracted following the sequential extraction procedure recommended by the Bureau Commun de Référence (BCR of the Commission of the European Communities. As an alternative to external calibration, the elements were quantified by spiking the extracted solutions with 112Cd, 63Cu, 208Pb and 66Zn and application of isotope dilution. The proposed approach was applied to a sample collected from a lake and two standard reference materials, NIST2704 river sediment from the National Institute of Standards & Technology and the BCR-277 estuarine sediment. Detection limits, for each extracted solution, varied from 0.31 to 0.53 mug L¹ for Cd, 0.92 to 2.9 mug L¹ for Cu, 0.22 to 1.1 mug L¹ for Pb and 1.3 to 7.6 mug L¹ for Zn. The sum of the metals concentration in the different fractions was compatible with 95% confidence level found amounts obtained with complete digestion of the samples and with the certified values of the standard reference materials.

  3. Study on accumulation of Fe, Pb, Zn, Ni and Cd in Nerita lineata and Thais bitubercularis from Tanjung Harapan and Teluk Kemang, Malaysia.

    Directory of Open Access Journals (Sweden)

    Tengku

    2017-01-01

    Full Text Available The presence of Cd, Cu, Zn, Ni, Fe, Al, Zn, Mn, Cr, and Sn were attributed to metal industries. Cu contamination was associated with piggery industry. Shipping activities contribute to elevated levels of Pb, Cu and As. Elevated levels of metals in the sediments are attributed to anthropogenic activities. Samples were collected in April 2012 and analysed using inductively coupled plasma mass spectrometry (ICP-MS. Fe is the most abundant metal in the tissue and shell compared to the rest of the metals. The concentrations of heavy metals in the soft tissues of Nerita lineata taken from Tanjung Harapan follow this order: Fe > Zn > Ni > Cu > Cd while in Thais bitubercularis, the metal concentrations were higher following the order of Fe > Zn > Cu > Ni > Cd. The samples taken from Teluk Kemang were higher and exhibited different trend for both organisms. Results from this study are useful for further exploration of Thais bitubercularis as accumulators of Cu, Cd, and Zn. For recommendation, more studies on monitoring the concentration level of heavy metals in marine environment should be done regularly and increase numbers of samples use to biomonitor the heavy metals in marine environment as it is important to have information or data regarding the quality of marine environment in order to control pollution such as water pollution from being contaminated with heavy metals. This is essential as the pollutants emit in the marine environment may affect marine lives as well as human’s health

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

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    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

  5. 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.

  6. Predicting the solubility and lability of Zn, Cd, and Pb in soils from a minespoil-contaminated catchment by stable isotopic exchange

    Science.gov (United States)

    Marzouk, E. R.; Chenery, S. R.; Young, S. D.

    2013-12-01

    The Rookhope catchment of Weardale, England, has a diverse legacy of contaminated soils due to extensive lead mining activity over four centuries. We measured the isotopically exchangeable content of Pb, Cd and Zn (E-values) in a large representative subset of the catchment soils (n = 246) using stable isotope dilution. All three metals displayed a wide range of %E-values (c. 1-100%) but relative lability followed the sequence Cd > Pb > Zn. A refinement of the stable isotope dilution approach also enabled detection of non-reactive metal contained within suspended sub-micron (dilution, in a diverse range of soil ecosystems within the catchment of an old Pb/Zn mining area. Assess the controlling influences of soil properties on metal lability and develop predictive algorithms for metal lability in the contaminated catchment based on simple soil properties (such as pH, organic matter (LOI), and total metal content). Examine the incidence of non-isotopically-exchangeable metal held within suspended colloidal particles (SCP-metal) in filtered soil solutions (<0.22 μm) by comparing E-values from isotopic abundance in solutions equilibrated with soil and in a resin phase equilibrated with the separated solution. Assess the ability of a geochemical speciation model, WHAM(VII), to predict metal solubility using isotopically exchangeable metal as an input variable.

  7. Disponibilidade e fracionamento de Cd, Pb, Cu e Zn em função do pH e tempo de incubação com o solo Availability and fractionation of Cd, Pb, Cu, AND Zn in soil as a function of incubation time and pH

    Directory of Open Access Journals (Sweden)

    Évio Eduardo Chaves de Melo

    2008-06-01

    Full Text Available O pH e o tempo de contato influenciam a distribuição dos metais entre frações do solo e a eficiência da fitoextração. Objetivou-se, neste trabalho estudar a disponibilidade dos metais Cd, Pb, Cu e Zn para a fitoextração, bem como suas redistribuições no solo, em função do tempo de incubação em solo com e sem calagem. O solo recebeu Cd, Pb, Cu e Zn nas doses 20, 150, 100 e 150 mg kg-1, respectivamente, na forma de sal solúvel. As amostras foram incubadas por 210, 180, 150, 120, 90, 60, 30 e 0,5 dia. Terminada a incubação, mucuna preta (Stizolobium aterrimum Piper & Tracy foi cultivada por 30 dias. EDTA (10 mmol kg-1 foi aplicado sete dias, antes da coleta das plantas. As amostras de solo foram submetidas à extração química e fracionada. A concentração de metais pesados e a calagem afetaram a produção de matéria seca da parte aérea e da raiz. Em solos sem calagem, o aumento da solubilidade dos metais aumentou a fitoextração de Cd e Zn, mesmo sem aplicação do EDTA. A aplicação do EDTA ao solo com calagem mostrou-se eficiente para a fitoextração de Pb e Cu. A calagem reduziu os teores disponíveis de Cd, Pb, Cu e Zn. A calagem provocou redução nos teores de Cd, Pb, Cu e Zn trocáveis e aumento nas frações matéria orgânica, óxidos de ferro amorfo e cristalino.It is known that pH and incubation time influence the distribution of metals into soil fractions and therefore affect phytoextraction. Taking this in account, the aim of this work was to study the fractionation and availability of heavy metals for phytoextraction, as a function of incubation period in soils with or without liming. The soil samples were applied to Cd, Pb, Cu, and Zn at concentrations of 20, 150, 100, and 150 mg kg-1, respectively, in the form of soluble salt. The samples were kept incubated for high incubation periods: 210, 180, 150, 120, 90, 60, 30, and 0,5 day. After that, velvetbean (Stizolobium aterrimum Piper & Tracy was cultivated

  8. Impact of shallowly deposited ore-bearing dolomites on local soil pollution aureoles of As, Cd, Pb, and Zn in an old mining area

    Energy Technology Data Exchange (ETDEWEB)

    Fabijanczyk, Piotr; Zawadzki, Jaroslaw [Warsaw Univ. of Technology (Poland). Environmental Engineering Faculty

    2012-10-15

    The study area, located in Upper Silesian Industrial Region, was rich in significant amounts of ores that were classified of Mississippi Valley type. Being these ores especially rich in Pb and Zn, an intense development of mining and ore extraction industry was verified in this area. The goal of this study was to investigate how local pollution aureoles of As, Cd, Pb, and Zn were influenced by the presence of shallowly deposited ore-bearing dolomites. Very extensive sampling campaign was carried out, and over 1,000 samples were collected in the area of about 150 km{sup 2}. Local aureoles of investigated metals were calculated for two soil layers. The first one covered the part of soil core from the soil surface to the depth of 20 cm and the second one from the depth of 40 cm to the depth of 60 cm. All spatial distributions of particular metals in soil were calculated by means of ordinary kriging using free softwares QGIS and SAGA. Maximum concentrations of Pb and Zn in soil in study area were very high, reaching over 24,000 and 77,000 mg/kg, respectively. Maximum concentrations of As and Cd were also very high, reaching about 1,000 mg/kg. Those maximum values were observed in the direct vicinity of the Boles?aw mine and its mine dumps. Almost all local aureoles were located within the range of ore-bearing dolomites. It was especially visible for Pb and Zn, minerals very common in ore deposits. Otherwise, local aureoles of As and Cd were more related with the vicinity of mines and other pollution sources, being more associated to the anthropogenic pollution than to the presence of ore-bearing dolomites. The aureoles of Pb and Zn, and in moderate degree of As, were associated with a mineral composition of ores. Differently, the location, the shape, and spatial pattern of Cd aureoles suggest that they were mostly influenced by anthropogenic pollution. Anthropogenic factors were dominating over the lithogenic ones and masking the influence of the shallowly deposited

  9. Enriquecimiento, disponibilidad y contaminación de metales traza (Cd, Cu, Pb y Zn en sedimentos de lagunas urbanas de Concepción-Chile Enrichment, availability and contamination of trace metals (Cd, Cu, Pb and Zn in sediments of urban lagoons in Concepción, Chile

    Directory of Open Access Journals (Sweden)

    Elizabeth González Sepúlveda

    2009-01-01

    Full Text Available Trace metals (Cd, Cu, Pb and Zn enrichment, availability and contamination in superficial sediments of three interconnected urban lagoons localized in Concepción-Chile, were evaluated. According to the results of geochemical fracctionation analysis, Cu and Pb are rather associated with oxi-hydroxides, Cd is associated with exchangeable and carbonates fraction, while Zn is mainly associated with organic, oxi-hydroxides and residual fraction. The estimation of the availability percentages indicate that Cu is the most mobile metal and the less mobile is the Cd. An evaluation of the geo-accumulation index and urban industrial pollution allowed to classify the studied zone as moderately to highly contaminated.

  10. Assessment of metal pollution in a former mining area in the NW Tunisia: spatial distribution and fraction of Cd, Pb and Zn in soil.

    Science.gov (United States)

    Othmani, Mohamed Ali; Souissi, Fouad; Durães, Nuno; Abdelkader, Moussi; da Silva, Eduardo Ferreira

    2015-08-01

    This study aims to evaluate the impact of the former mining Touiref district (NW Tunisia) on the spatial distribution of metal contamination. In order to characterize the metal content of the tailings and to assess how far the soils from the district could be impacted by metals, a sampling campaign was conducted. According to the spatial distribution concentration maps of potential toxic elements (PTE), the highest concentrations occur near the flotation tailings and in mining facilities and decrease abruptly with distance. These results confirm that wind is the main agent capable of dispersing metals in a W-E direction, with concentrations exceeding the standards of soil quality for Cd, Pb and Zn over several hundred metres away from the source, facilitated by the small-size fraction and low cohesion of tailings particles. Chemical fractionation showed that Pb and Cd were mainly associated with the acid-soluble fraction (carbonates) and Fe-(oxy) hydroxides, while Zn was mainly associated with Fe-(oxy) hydroxides but also with sulphides. Thus, the immobilization of metals in solution may be favoured by the alkaline conditions, promoted by carbonates dissolution. However, being carbonate important-bearing phases of Cd and Pb (but also for Zn), the dissolution facility of these minerals may enhance the release of metals, particularly far away from the mine where the physicochemical conditions can be different. Also, the metal uptake by plants in these alkaline conditions may be favoured, especially if secondary phases with high sorption ability are reduced at this site. A remediation plan to this area is needed, with particularly attention in the confinement of the tailings.

  11. Geographical and pedological drivers of distribution and risks to soil fauna of seven metals (Cd, Cu, Cr, Ni, Pb, V and Zn) in British soils

    International Nuclear Information System (INIS)

    Spurgeon, David J.; Rowland, Philip; Ainsworth, Gillian; Rothery, Peter; Long, Sara; Black, Helaina I.J.

    2008-01-01

    Concentrations of seven metals were measured in over 1000 samples as part of an integrated survey. Sixteen metal pairs were significantly positively correlated. Cluster analysis identified two clusters. Metals from the largest (Cr, Cu, Ni, V, Zn), but not the smallest (Cd, Pb) cluster were significantly negatively correlated with spatial location and soil pH and organic matter content. Cd and Pb were not correlated with these parameters, due possibly to the masking effect of recent extensive release. Analysis of trends with soil properties in different habitats indicated that general trends may not necessarily be applicable to all areas. A risk assessment indicated that Zn poses the most widespread direct risk to soil fauna and Cd the least. Any risks associated with high metal concentrations are, however, likely to be greatest in habitats such as arable and horticultural, improved grassland and built up areas where soil metal concentrations are more frequently elevated. - Metal distributions and risks explained by balance of sources and soil property effects on fate

  12. Certification of trace element contents (As, Cd, Co, Cu, Fe, Mn, Hg, Na, Pb and Zn) in a fly ash obtained from the combustion of pulverised coal

    International Nuclear Information System (INIS)

    Griepink, B.; Colinet, E.; Guzzi, G.; Haemers, L.; Muntau, H.

    1983-01-01

    The element contents of As, Cd, Co, Cu, Fe, Mn, Hg, Na, Pb and Zn of a fly ash from pulverised coal are certified. The procedures and their results for the homogenisation, the contamination and homogeneity checks and the analytical campaign are reported. The certified mass fractions and indicative values for Cr, Ni, Th, V and water soluble sulphate are given. The work was carried out within the framework of the activities of the Community Bureau of Reference (BCR) of the Commission of the European Communities. (orig.) [de

  13. Bioaccumulation of metals (Cd, Cu, Ni, Pb and Zn) in suspended cultures of blue mussels exposed to different environmental conditions

    DEFF Research Database (Denmark)

    Maar, Marie; Larsen, Martin Mørk; Tørring, Ditte Bruunshøj

    2015-01-01

    corresponding to Good Ecological Status (GES) in the European Union Water Framework Directive (WFD) and in future climate change scenarios (higher metal concentrations and higher temperatures). For this purpose, GES is interpreted as good chemical status for the metals using the Environmental Quality Standards...... targets for Cd, Ni and Pb are not protective with respect to marine mussel production and probably should be reduced for marine waters. Climate changes may increase the metal contamination of mussels, but not to any critical level at the relatively unpolluted study sites. In conclusion, WFD targets should...

  14. Differences in the mobility of Cd, Cu, Pb and Zn during composting of two types of household bio-waste collected in four seasons.

    Science.gov (United States)

    Hanc, Ales; Szakova, Jirina; Ochecova, Pavla

    2014-09-01

    The objective of this study was to evaluate the mobility of Cd, Cu, Pb and Zn during 3 different compost aeration rates of household bio-waste, originating in urban settlement (U-bio-waste) and family house buildings (F-bio-waste). The first two weeks, when the thermophilic composting phase became, the highest decline of exchangeable content was recorded. After 12 weeks of composting, lower exchangeable content was found in the case of U-bio-waste composts than F-bio-waste composts, despite higher loss of fresh mass. The order of fractions in both final composts was as follows: residual>oxidizable>reducible>exchangeable. The exchangeable portion of total content in final composts decreased in this order: Zn (17%), Cd (11%), Pb (4%) and Cu (3%). Regarding the low exchangeable content of heavy metals and high-quality organic matter, these types of composts could be used not only as fertilizer, but for remediation of metals contaminated land. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. A two-step leaching method designed based on chemical fraction distribution of the heavy metals for selective leaching of Cd, Zn, Cu, and Pb from metallurgical sludge.

    Science.gov (United States)

    Wang, Fen; Yu, Junxia; Xiong, Wanli; Xu, Yuanlai; Chi, Ru-An

    2018-01-01

    For selective leaching and highly effective recovery of heavy metals from a metallurgical sludge, a two-step leaching method was designed based on the distribution analysis of the chemical fractions of the loaded heavy metal. Hydrochloric acid (HCl) was used as a leaching agent in the first step to leach the relatively labile heavy metals and then ethylenediamine tetraacetic acid (EDTA) was applied to leach the residual metals according to their different fractional distribution. Using the two-step leaching method, 82.89% of Cd, 55.73% of Zn, 10.85% of Cu, and 0.25% of Pb were leached in the first step by 0.7 M HCl at a contact time of 240 min, and the leaching efficiencies for Cd, Zn, Cu, and Pb were elevated up to 99.76, 91.41, 71.85, and 94.06%, by subsequent treatment with 0.2 M EDTA at 480 min, respectively. Furthermore, HCl leaching induced fractional redistribution, which might increase the mobility of the remaining metals and then facilitate the following metal removal by EDTA. The facilitation was further confirmed by the comparison to the one-step leaching method with single HCl or single EDTA, respectively. These results suggested that the designed two-step leaching method by HCl and EDTA could be used for selective leaching and effective recovery of heavy metals from the metallurgical sludge or heavy metal-contaminated solid media.

  16. Effective removal of heavy metal ions Cd2+, Zn2+, Pb2+, Cu2+ from aqueous solution by polymer-modified magnetic nanoparticles

    International Nuclear Information System (INIS)

    Ge, Fei; Li, Meng-Meng; Ye, Hui; Zhao, Bao-Xiang

    2012-01-01

    We prepared novel Fe 3 O 4 magnetic nanoparticles (MNPs) modified with 3-aminopropyltriethoxysilane (APS) and copolymers of acrylic acid (AA) and crotonic acid (CA). The MNPs were characterized by transmission electron microscopy, X-ray diffraction, infra-red spectra and thermogravimetric analysis. We explored the ability of the MNPs for removing heavy metal ions (Cd 2+ , Zn 2+ , Pb 2+ and Cu 2+ ) from aqueous solution. We investigated the adsorption capacity of Fe 3 O 4 -APS-AA-co-CA at different pH in solution and metal ion uptake capacity as a function of contact time and metal ion concentration. Moreover, adsorption isotherms, kinetics and thermodynamics were studied to understand the mechanism of the synthesized MNPs adsorbing metal ions. In addition, we evaluated the effect of background electrolytes on the adsorption. Furthermore, we explored desorption and reuse of MNPs. Fe 3 O 4 -APS-AA-co-CA MNPs are excellent for removal of heavy metal ions such as Cd 2+ , Zn 2+ , Pb 2+ and Cu 2+ from aqueous solution. Furthermore, the MNPs could efficiently remove the metal ions with high maximum adsorption capacity at pH 5.5 and could be used as a reusable adsorbent with convenient conditions.

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

    Directory of Open Access Journals (Sweden)

    Shinya Hosokawa

    Full Text Available Accumulation of Cu, Zn, Cd, and Pb in the sediment of seagrass ecosystems was examined using mesocosm experiments containing Zostera marina (eelgrass and reference pools. Lead was approximately 20-fold higher in the surface sediment in the eelgrass pool than in eelgrass leaves and epiphytes on the eelgrass leaves, whereas zinc and cadmium were significantly lower in the surface sediment than in the leaves, with intermediate concentrations in epiphytes. Copper concentrations were similar in both the surface sediment and leaves but significantly lower in epiphytes. Carbon and nitrogen contents increased significantly with increasing δ13C in surface sediments of both the eelgrass and reference pools. Copper, Zn, Cd, and Pb also increased significantly with increasing δ13C in the surface sediment in the eelgrass pool but not in the reference pool. By decomposition of eelgrass leaves with epiphytes, which was examined in the eelgrass pool, copper and lead concentrations increased more than 2-fold and approximately a 10-fold, whereas zinc and cadmium concentrations decreased. The high copper and lead concentrations in the surface sediment result from accumulation in decomposed, shed leaves, whereas zinc and cadmium remobilized from decomposed shed leaves but may remain at higher concentrations in the leaves than in the original sediments. The results of our mesocosm study demonstrate that whether the accumulation or remobilization of trace metals during the decomposition of seagrass leaves is trace metal dependent, and that the decomposed seagrass leaves can cause copper and lead accumulation in sediments in seagrass ecosystems.

  18. Effect of pyrolysis temperature on chemical form, behavior and environmental risk of Zn, Pb and Cd in biochar produced from phytoremediation residue.

    Science.gov (United States)

    Huang, Hui; Yao, Wenlin; Li, Ronghua; Ali, Amjad; Du, Juan; Guo, Di; Xiao, Ran; Guo, Zhanyu; Zhang, Zengqiang; Awasthi, Mukesh Kumar

    2018-02-01

    This study aimed to evaluate the chemical forms, behavior and environmental risk of heavy metal (HMs) Zn, Pb and Cd in phytoremediation residue (PMR) pyrolyzed at 350 °C, 550 °C and 750 °C, respectively. The behavior of HMs variation during the PMR pyrolysis process was analyzed and the potential HMs environmental risk of phytoremediation residue biochars (PMB) was assessed which was seldom investigated before. The results showed that the pyrolysis temperature increase decreased the soluble/exchangeable HMs fraction and alleviated the HMs bioavailability. When the temperature was over 550 °C, the adsorbed Zn(II), Pb(II) and Cd(II) were turned into oxides forms and concentrated in PMB with more stable forms exhibiting lower risk assessment code and potential ecological risk index. The ecotoxicity test showed higher pyrolysis temperature favored the reduction of PMB ecotoxicity. It is suggested that pyrolysis temperature above 550°C may be suitable for thermal treatment of PMR with acceptable environmental risk. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Accumulation of Pb, Hg, Cd, Se, Sc, Cr, Rb, Fe, Zn, Co in the plants and sludges of the Lake Balaton

    International Nuclear Information System (INIS)

    Teherani, D.K.; Altmann, H.; Wallisch, G.

    1981-01-01

    Various plants (Ceratophyllum demersum, Potamogeton pectinatus, Myriophyllum spicatum) and mud samples taken from Lake Balaton (Paloznak, Balatonfuezfoe) in June 1978 were analyzed for Se, Cr, Sc, Rb, Fe, Zn, Co by neutron activation analysis and for Cd, Pb, Hg by atomic absorption spectrometry. The concentration values found for Se ranged between 0.25-1.2 ppm (plant) and 0.99-1.47 ppm (mud), for Cr 1.6-6 ppm (plant) and 4.85-40.75 ppm (mud), for Sc 0.4-0.75 ppm (plant) and 3.25-5.87 ppm (mud), for Rb 6.75-16 ppm (plant) and 17-48.75 ppm (mud), for Fe 636.7-4491 ppm (plant) and 11034-12057 ppm (mud), for Zn 20.5-38.5 ppm (plant) and 29.75-41.75 ppm (mud), for Co 0.77-4.75 ppm (plant) and 4.87-5.5 ppm (mud), for Pb 4.5-23.5 ppm (plant) and 18-28 ppm (mud), for Cd <0.03 ppm (plant, mud), for Hg <0.01-0.07 ppm (plant) and 0.04-0.08 ppm (mud). (author)

  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. Comprehensive risk assessment and source identification of selected heavy metals (Cu, Cd, Pb, Zn, Hg, As) in tidal saltmarsh sediments of Shuangtai Estuary, China.

    Science.gov (United States)

    Liu, Chang-Fa; Li, Bing; Wang, Yi-Ting; Liu, Yuan; Cai, Heng-Jiang; Wei, Hai-Feng; Wu, Jia-Wen; Li, Jin

    2017-10-06

    Heavy metals do not degrade and can remain in the environment for a long time. In this study, we analyzed the effects of Cu, Cd, Pb, Zn, Hg, and As, on environmental quality, pollutant enrichment, ecological hazard, and source identification of elements in sediments using data collected from samples taken from Shuangtai tidal wetland. The comprehensive pollution indices were used to assess environmental quality; fuzzy similarity analysis and geoaccumulation index were used to analyze pollution accumulation; correlation matrix, principal component analysis, and clustering analysis were used to analyze pollution source; environmental risk index and ecological risk index were used to assess ecological risk. The results showed that the environmental quality was either clean or almost clean. Pollutant enrichment analysis showed that the four sub-regions had similar pollution-causing metals to the background values of the soil element of the Liao River Plain, which were ranked according to their similarity. Source identification showed that all the elements were correlated. Ecological hazard analysis showed that the environmental risk index in the study area was less than zero, posing a low ecological risk. Ecological risk of the six elements was as follows: As > Cd > Hg > Cu > Pb > Zn.

  2. Characterization of Cd-, Pb-, Zn-resistant endophytic Lasiodiplodia sp. MXSF31 from metal accumulating Portulaca oleracea and its potential in promoting the growth of rape in metal-contaminated soils.

    Science.gov (United States)

    Deng, Zujun; Zhang, Renduo; Shi, Yang; Hu, Li'ao; Tan, Hongming; Cao, Lixiang

    2014-02-01

    The aim of this study was to characterize the features of a Cd-, Pb-, and Zn-resistant endophytic fungus Lasiodiplodia sp. MXSF31 and to investigate the potential of MXSF31 to remove metals from contaminated water and soils. The endophytic fungus was isolated from the stem of Portulaca oleracea growing in metal-contaminated soils. The maximum biosorption capacities of MXSF31 were 3.0 × 10(3), 1.1 × 10(4), and 1.3 × 10(4) mg kg(-1) for Cd, Pb, and Zn, respectively. The biosorption processes of Cd, Pb, and Zn by MXSF31 were well characterized with the pseudo-second-order kinetic model. The biosorption isotherm processes of Pb and Zn by the fungus were fitted better with the Langmuir model, while the biosorption processes of Cd was better fitted with the Freundlich model. The biosorption process of MXSF31 was attributed to the functional groups of hydroxyl, amino, carbonyl, and benzene ring on the cell wall. The active biomass of the strain removed more Cd, Pb, and Zn (4.6 × 10(4), 5.6 × 10(5), and 7.0 × 10(4) mg kg(-1), respectively) than the dead biomass. The inoculation of MXSF31 increased the biomass of rape (Brassica napus L.), the translocation factor of Cd, and the extraction amount of Cd by rape in the Cd+Pb-contaminated soils. The results indicated that the endophytic fungus strain had the potential to remove heavy metals from water and soils contaminated by multiple heavy metals, and plants accumulating multiple metals might harbor diverse fungi suitable for bioremediation of contaminated media.

  3. Corrosion Behavior of Alloy 625 in PbSO4-Pb3O4-PbCl2-ZnO-10 Wt Pct CdO Molten Salt Medium

    Science.gov (United States)

    Mohammadi Zahrani, E.; Alfantazi, A. M.

    2012-08-01

    Corrosion behavior and degradation mechanisms of alloy 625 under a 47.288 PbSO4-12.776 Pb3O4-6.844PbCl2-23.108ZnO-10CdO (wt pct) molten salt mixture under air atmosphere were studied at 873 K, 973 K, and 1073 K (600 °C, 700 °C, and 800 °C). Electrochemical impedance spectroscopy (EIS), open circuit potential (OCP) measurements, and potentiodynamic polarization techniques were used to evaluate the degradation mechanisms and characterize the corrosion behavior of the alloy. Morphology, chemical composition, and phase structure of the corrosion products and surface layers of the corroded specimens were studied by scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) and X-ray map analyses. Results confirmed that during the exposure of alloy 625 to the molten salt, chromium was mainly dissolved through an active oxidation process as CrO3, Cr2O3, and CrNbO4, while nickel dissolved only as NiO in the system. Formation of a porous and nonprotective oxide layer with low resistance is responsible for the weak protective properties of the barrier layer at high temperatures of 973 K and 1073 K (700 °C and 800 °C). There were two kinds of attack for INCONEL 625, including general surface corrosion and pitting. Pitting corrosion occurred due to the breakdown of the initial oxide layer by molten salt dissolution of the oxide or oxide cracking.

  4. 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 Rhodotorula sp CBSB79 showed higher potentials to improve extraction efficacy of Cd, Pb, Zn, and Cu by Brassica seedlings in the field.

  5. Associations between standardized school performance tests and mixtures of Pb, Zn, Cd, Ni, Mn, Cu, Cr, Co, and V in community soils of New Orleans

    International Nuclear Information System (INIS)

    Zahran, Sammy; Mielke, Howard W.; Weiler, Stephan; Hempel, Lynn; Berry, Kenneth J.; Gonzales, Christopher R.

    2012-01-01

    In New Orleans a strong inverse association was previously identified between community soil lead and 4th grade school performance. This study extends the association to zinc, cadmium, nickel, manganese, copper, chromium, cobalt, and vanadium in community soil and their comparative effects on 4th grade school performance. Adjusting for poverty, food security, racial composition, and teacher-student ratios, regression results show that soil metals variously reduce and compress student scores. Soil metals account for 22%–24% while food insecurity accounts for 29%–37% of variation in school performance. The impact on grade point averages were Ni > Co > Mn > Cu ∼Cr ∼ Cd > Zn > Pb, but metals are mixtures in soils. The quantities of soil metal mixtures vary widely across the city with the largest totals in the inner city and smallest totals in the outer city. School grade point averages are lowest where the soil metal mixtures and food insecurity are highest. - Highlights: ► Mixtures of metals vary; largest totals in the inner city and lowest in the outer city. ► An inverse association between soil Pb and 4th grade school performance is known. ► Assuming the same exposure pathway, multiple metals are compared to performance. ► Soil metals account for 22%–24% of variation in school test performance. ► Soil metal plus food insecurity accounts for 54% of explained variance. - Controlling for potential confounding variables, the accumulation of metals (Pb, Zn, Cd, Ni, Mn, Cu, Cr, and Co) in neighborhood soils is significantly negatively associated with 4th grade school performance on standardized tests in New Orleans.

  6. 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 CaCl 2 . 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 CaCl 2 -and DTPA-extractable Cd, Cu, Pb and Zn concentrations were significantly (p soils, especially at 5% application rate, than those in the unamended soil. Soil pH values were significantly correlated with CaCl 2 -extractable metal concentrations (p 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 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.

  7. 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.

  8. Succulent species differ substantially in their tolerance and phytoextraction potential when grown in the presence of Cd, Cr, Cu, Mn, Ni, Pb, and Zn.

    Science.gov (United States)

    Zhang, Chengjun; Sale, Peter W G; Clark, Gary J; Liu, Wuxing; Doronila, Augustine I; Kolev, Spas D; Tang, Caixian

    2015-12-01

    Plants for the phytoextraction of heavy metals should have the ability to accumulate high concentrations of such metals and exhibit multiple tolerance traits to cope with adverse conditions such as coexistence of multiple heavy metals, high salinity, and drought which are the characteristics of many contaminated soils. This study compared 14 succulent species for their phytoextraction potential of Cd, Cr, Cu, Mn, Ni, Pb, and Zn. There were species variations in metal tolerance and accumulation. Among the 14 succulent species, an Australian native halophyte Carpobrotus rossii exhibited the highest relative growth rate (20.6-26.6 mg plant(-1) day(-1)) and highest tolerance index (78-93%), whilst Sedum "Autumn Joy" had the lowest relative growth rate (8.3-13.6 mg plant(-1) day(-1)), and Crassula multicava showed the lowest tolerance indices (phytoextraction of these heavy metals than other species. These findings suggest that Carpobrotus rossii is a promising candidate for phytoextraction of multiple heavy metals, and the aquatic or semiterrestrial Crassula helmsii is suitable for phytoextraction of Cd and Zn from polluted waters or wetlands.

  9. Evaluation of heavy metals (Cr, Fe, Ni, Cu, Zn, Cd, Pb and Hg) in water, sediments and water lily (Eichornia crassipes) from Jose Antonio Alzate dam

    International Nuclear Information System (INIS)

    Avila P, P.

    1995-01-01

    Water, sediments and water lily (Eichornia crassipes) from the Jose Antonio Alzate Dam were analyzed in order to determine concentrations of chromium, iron, nickel, copper, zinc, cadmium, lead and mercury. Mercury, lead, chromium and iron were found in concentrations above permissible limits in water, and in high concentrations in sediments. Cadmium, nickel, copper and zinc never were found in concentrations above permissible limits in water. The highest concentrations of heavy metals in water lily were found in the root. Accumulation factors decreased in the following order: Zn> Cr> Fe> Ni> Cu> Pb> Hg and Cd. Statistical differences (α < 0.5) between the collection samples dates was observed. High correlations between metals concentrations in superficial water, sediment and water hyacinth were also observed. These correlations could indicate that the heavy metals studied here, are originated from a natural source such as sediments or from an industrial source. (Author)

  10. Determination of Cu, Zn, Pb and Cd by Atomic Emission Spectrometry with Inductively Coupled Plasma in Organs of the Specie Gambusia punctata (Poeciliidae)

    International Nuclear Information System (INIS)

    Argota Perez, George; Argota Coello, Humberto; Rodriguez Amado, Jesus; Fernandez Heredia, Angel

    2013-01-01

    The aim of this research was to adequate the ICP-AES method to the quantification of Cu, Zn, Pb and Cd in brain, liver and gills of the specie Gambusia punctata, in order to know the level of exposure of the ecosystems San Juan and File in Santiago de Cuba province. To achieve the fitness for purpose of the method, limits of detection, reproducibility and accuracy were evaluated using reference certificated materials of fishes. The biological samples were classified according the ecosystem, length, sex and organ. It were dried, digested with mix of acids and the metals measured in the spectrometer. The results demonstrated that factors as length and sex have not influence in the bioaccumulation, whereas the gill was the organ where all the elements were bioaccumulated. Finally, due that the smallest concentrations of metals were in the File ecosystem, it could be used as an environmental reference

  11. BIOSORCIÓN DE Cd, Pb y Zn POR BIOMASA PRETRATADA DE ALGAS ROJAS, CÁSCARA DE NARANJA Y TUNA

    Directory of Open Access Journals (Sweden)

    Lissette Vizcaíno Mendoza

    2015-01-01

    Full Text Available Debido a su movilidad en los ecosistemas y a su toxicidad para las formas superiores de vida,los metales pesados Cd, Pb y Zn son priorizados como unos de los contaminantes inorgánicosmás importantes debido al alto riesgo que representan para el medio ambiente. Con el objeto dedisminuir su concentración se diseñó un sistema para evaluar su remoción empleando biomasade algas rojas, cáscaras de naranja (Citrus sp. y tuna guajira (Opuntia sp.. Se estudió la influenciadel pretratamiento y el empaquetamiento mediante ensayos tipo batch, en los que se emplearonsoluciones de sodio y calcio. Se obtuvo como resultado una mayor capacidad de sorción de lasalgas modificadas con NaOH 0.1 N y de la naranja y la tuna con modificación sucesiva con NaOH yCaCl20.2 M, y una afección poco significativa (≤1% del proceso de sorción al empacar la biomasael placas planas de tul poliéster. La eficiencia de remoción se determinó mediante un reactor deflujo continuo de columna fija con un volumen líquido de 400 mL, 75 g de biomasa y tiemposde retención promedio de 1 y 2 h. Los resultados mostraron una eficiencia similar de las tresbiomasas para remover Cd y Pb, con promedios superiores al 95%, mientras que el Zn se removiócon mejor eficiencia (62% al emplear tuna modificada como sorbente. Finalmente, el materialse calcinó a 700 °C con lo que se obtuvo una ceniza estable frente a soluciones ácidas, lo cualgarantiza la captura de los metales removidos.

  12. Diffusion coefficients for Tl, Pb, Cd, In, Zn, Bi, As, Mo and Sb in hydrous rhyolite at 100-200 MPa

    Science.gov (United States)

    Berlo, Kim; Brooker, Richard; Wilke, Max

    2014-05-01

    A series of experiments have been conducted to determine the diffusivities of Tl, Pb, Cd, In, Zn, Bi, As, Mo and Sb in hydrous rhyolitic melt. Diffusion experiments used two adjoining glass cylinder of the same hydrous composition, one doped with the elements of interest at ~ 100 ppm. These couples were rapidly heated to 850, 1000 and 1150°C at 100-200 MPa for a few hours. After quenching the sectioned charges were analyzed by both synchrotron XRF (The Diamond Light Source) and LA-ICP-MS (University of Oxford). The data shows excellent correlation between these two techniques. The diffusion profiles were fitted to a 1-D diffusion couple equation to determine the diffusivities and fitting to the different temperature runs defined the Arrhenius parameters. We find that for 850°C the diffusion coefficients follow the trend Tl>Pb>Cd>Zn>In>Bi>As>Sb>Mo. Additional experiments were performed with either S or Cl added (to both sides of the diffusion couple). In general S increases the diffusion rate of all metals except Mo and Sb, which diffuse slower in the presence of S. Chlorine also speeds up the diffusion of metals with the exception of In, Mo and Sb. The systematic change in diffusivities of these metals and their different behaviour in the presence of the ligands that are also observed to be significant in volcanic gases, are important in determining the distribution of these metals during degassing (e.g. MacKenzie and Canil, 2008). This is particularly important in a dynamic environment such as a volcanic conduit. There are also implications for economic exploration and well as hazard mitigation.

  13. Bioaccumulation of metals (Cd, Cu, Ni, Pb and Zn) in suspended cultures of blue mussels exposed to different environmental conditions

    Science.gov (United States)

    Maar, Marie; Larsen, Martin Mørk; Tørring, Ditte; Petersen, Jens Kjerulf

    2018-02-01

    Farming of suspended mussels is important for generating high protein food and animal feed or for removing nutrients in eutrophic systems. However, the harvested mussels must not be severely contaminated by pollutants posing a potential health risk for the consumers. The present study estimated the bioaccumulation of cadmium, copper, nickel, lead and zinc in suspended blue mussels (Mytilus edulis L.) in the Limfjorden, Denmark, based on observations and modelling. Modelling was used to assess the suitability of suspended blue mussels as animal feed and food products at sea water metal concentrations corresponding to Good Ecological Status (GES) in the European Union Water Framework Directive (WFD) and in future climate change scenarios (higher metal concentrations and higher temperatures). For this purpose, GES is interpreted as good chemical status for the metals using the Environmental Quality Standards (EQS) defined in the WFD priority substance daughter directives. Observations showed that suspended mussels were healthy with respect to metal pollution and generally less polluted than benthic mussels due to the smaller contact with the contaminated sediment. The model results showed that the WFD targets for Cd, Ni and Pb are not protective with respect to marine mussel production and probably should be reduced for marine waters. Climate changes may increase the metal contamination of mussels, but not to any critical level at the relatively unpolluted study sites. In conclusion, WFD targets should be revised to assure that the corresponding body burdens of metals in mussels are below the safety limits according to the EU Directives and the Norwegian classification for animal feed and food production.

  14. An investigation of the evolution of evolution of distribution and accumulation of heavy metals(Cr, Ni, Cu, Cd, Zn and Pb) in Anzali wetland's sediments

    International Nuclear Information System (INIS)

    Sartaj, M.; Fatollahi, F.; Filizadeh, Y.

    2005-01-01

    To investigate the precipitation of heavy metals in Anzali wetland and evaluate its refining performance this study was carried out on the wetland. Monthly samples of sediments from 15 stations including inlets, outlets and some internal locations in the wetland were collected and analyzed over a period of six months (July - December 2002). Sediment samples were analyzed for six metals of Cr, Cd, Pb, Zn, Cu and Ni. Wet digestion method was employed for extraction of metals in samples by and through a solution containing HN03 and HCL. Atomic Adsorption spectrophotometry was employed for measurement of the heavy metals. Statistical methods, including analysis of variance (ANOVA), correlation and Cluster analysis were used for analysis of the data. The results indicated that concentration of heavy metals present in sediments (collected from different stations and at different times) here significantly different. Among the metals studied, Zn was of the highest concentration Heavy metal concentrations in stations 1 1, 12 and 13 were lower than in other stations. Sediments in station 5 contained the highest concentrations of heavy metals among all sediments. It can be stated that concentration of heavy metals decreases with an increase in the distance from delta of rivers entering the wetland.2. This is due to the role and performance of wetland chemical contents in reduction of pollutants, the self-purification action of wetland as well as precipitation of heavy metals at the beginning of the entries into the wetland

  15. Effects of heavy metal concentrations (Cd, Zn and Pb) in agricultural soils near different emission sources on quality, accumulation and food safety in soybean [Glycine max (L.) Merrill].

    Science.gov (United States)

    Salazar, María Julieta; Rodriguez, Judith Hebelen; Leonardo Nieto, Gastón; Pignata, María Luisa

    2012-09-30

    Argentina is one of the major producers of soybean in the world, this generates a high global demand for this crop leading to find it everywhere, even close to human activities involving pollutant emissions. This study evaluated heavy metal content, the transfer of metals and its relation to crop quality, and the toxicological risk of seed consumption, through soil and soybean sampling. The results show that concentrations of Pb and Cd in soils and soybeans at several sites were above the maximum permissible levels. The heavy metal bioaccumulation depending on the rhizosphere soil compartment showed significant and high regression coefficients. In addition, the similar behavior of Cd and Zn accumulation by plants reinforces the theory of other studies indicating that these metals are incorporated into the plant for a common system of transport. On the other hand, the seed quality parameters did not show a clear pattern of response to metal bioacumulation. Taken together, our results show that soybeans grown nearby to anthropic emission sources might represent a toxicological hazard for human consumption in a potential Chinese consumer. Hence, further studies should be carried out taking into account the potential negative health effects from the consumption of soybeans (direct or indirect through consumption of meat from cattle) in these conditions. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Effects of heavy metal concentrations (Cd, Zn and Pb) in agricultural soils near different emission sources on quality, accumulation and food safety in soybean [Glycine max (L.) Merrill

    International Nuclear Information System (INIS)

    Salazar, María Julieta; Rodriguez, Judith Hebelen; Nieto, Gastón Leonardo; Pignata, María Luisa

    2012-01-01

    Highlights: ► Soybean grown near metal sources presents a toxicological hazard from heavy metals for Chinese consumers. ► Rhizosphere soil is the most suitable compartment for toxicological studies. ► Soil guidelines should be modified considering the exchangeable metals. - Abstract: Argentina is one of the major producers of soybean in the world, this generates a high global demand for this crop leading to find it everywhere, even close to human activities involving pollutant emissions. This study evaluated heavy metal content, the transfer of metals and its relation to crop quality, and the toxicological risk of seed consumption, through soil and soybean sampling. The results show that concentrations of Pb and Cd in soils and soybeans at several sites were above the maximum permissible levels. The heavy metal bioaccumulation depending on the rhizosphere soil compartment showed significant and high regression coefficients. In addition, the similar behavior of Cd and Zn accumulation by plants reinforces the theory of other studies indicating that these metals are incorporated into the plant for a common system of transport. On the other hand, the seed quality parameters did not show a clear pattern of response to metal bioacumulation. Taken together, our results show that soybeans grown nearby to anthropic emission sources might represent a toxicological hazard for human consumption in a potential Chinese consumer. Hence, further studies should be carried out taking into account the potential negative health effects from the consumption of soybeans (direct or indirect through consumption of meat from cattle) in these conditions.

  17. Study of Fe, Zn, Cu, Cd, Pb concentrations in liver, kidney and muscle tissue of cow and sheep marketed in Hamedan in 2011

    Directory of Open Access Journals (Sweden)

    S Sobhanardakani

    2012-11-01

    Full Text Available Importance of heavy metals in food safety and detrimental effects of their high concentrations in food stuff is well documented. In this study, concentrations of Fe, Zn, Cu, Cd and Pb in kidney, liver and muscle tissues of cow and sheep at Hamedan retails were evaluated. A total number of 180 samples was assessed for the amount of heavy metals as ppb in wet weight. For this, wet-digestion method was used to determine the concentration of given elements by ICP (Varian ES-710. Results showed that the highest concentration of heavy metals was determined in the liver and kidney samples, while the lowest concentration was found in muscle tissue. Among the heavy metals, Fe in cow’s liver had the highest concentration (25507±879 ppb and Cd in muscle tissue of sheep has the lowest concentration (192±54 ppb. In overall, accumulation of heavy metals in tissues of cows was higher than sheep. Statistical comparison of accumulated metals concentration in various tissues of these two animal groups showed significant difference (P

  18. Contamination and Health Risks from Heavy Metals (Cd and Pb and Trace Elements (Cu and Zn in Dairy Products

    Directory of Open Access Journals (Sweden)

    Hamid Reza Ghafari

    2017-08-01

    Conclusion: Considering the serious contamination of some brands of butter and cheese by Cu and Pb, a control of heavy metals and trace elements levels during the whole production processing of dairy products must be applied.

  19. 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.

  20. Geochemical position of Pb, Zn and Cd in soils near the Olkusz mine/smelter, South Poland: effects of land use, type of contamination and distance from pollution source.

    Science.gov (United States)

    Chrastný, Vladislav; Vaněk, Aleš; Teper, Leslaw; Cabala, Jerzy; Procházka, Jan; Pechar, Libor; Drahota, Petr; Penížek, Vít; Komárek, Michael; Novák, Martin

    2012-04-01

    The soils adjacent to an area of historical mining, ore processing and smelting activities reflects the historical background and a mixing of recent contamination sources. The main anthropogenic sources of metals can be connected with historical and recent mine wastes, direct atmospheric deposition from mining and smelting processes and dust particles originating from open tailings ponds. Contaminated agriculture and forest soil samples with mining and smelting related pollutants were collected at different distances from the source of emission in the Pb-Zn-Ag mining area near Olkusz, Upper Silesia to (a) compare the chemical speciation of metals in agriculture and forest soils situated at the same distance from the point source of pollution (paired sampling design), (b) to evaluate the relationship between the distance from the polluter and the retention of the metals in the soil, (c) to describe mineralogy transformation of anthropogenic soil particles in the soils, and (d) to assess the effect of deposited fly ash vs. dumped mining/smelting waste on the mobility and bioavailability of metals in the soil. Forest soils are much more affected with smelting processes than agriculture soils. However, agriculture soils suffer from the downward metal migration more than the forest soils. The maximum concentrations of Pb, Zn, and Cd were detected in a forest soil profile near the smelter and reached about 25 g kg(- 1), 20 g kg(- 1) and 200 mg kg(- 1) for Pb, Zn and Cd, respectively. The metal pollutants from smelting processes are less stable under slightly alkaline soil pH then acidic due to the metal carbonates precipitation. Metal mobility ranges in the studied forest soils are as follows: Pb > ZnCd for relatively circum-neutral soil pH (near the smelter), Cd > Zn > Pb for acidic soils (further from the smelter). Under relatively comparable pH conditions, the main soil properties influencing metal migration are total organic carbon and cation exchange

  1. PM2.5 particulates and metallic elements (Ni, Cu, Zn, Cd and Pb) study in a mixed area of summer season in Shalu, Taiwan.

    Science.gov (United States)

    Fang, Guor-Cheng; Xiao, You-Fu; Zhuang, Yuan-Jie; Cho, Meng-Hsien; Huang, Chao-Yang; Tsai, Kai-Hsiang

    2017-08-01

    PM 2.5 has become an important environmental issue in Taiwan during the past few years. Moreover, electricity increased significantly during the summertime and TTPP generated by coal burning base is the main electricity provider in central Taiwan. Therefore, summer season has become the main research target in this study. The ambient air concentrations of particulate matter PM 2.5 and PM 10 collected by using VAPS at a mixed characteristic sampling site were studied in central Taiwan. The results indicated that the average daytime PM 2.5 and PM 10 particulate concentrations were occurred in May and they were 44.75 and 57.77 µg/m 3 in this study. The results also indicated that the average nighttime PM 2.5 and PM 10 particulate concentrations were occurred in June and they were 38.19 and 45.79 µg/m 3 in this study. The average PM 2.5 /PM 10 ratios were 0.7 for daytime, nighttime and 24-h sampling periods in the summer for this study. This value was ranked as the lowest ratios when compared to the other seasons in previous study. Noteworthy, the results further indicated that the metallic element Pb has the mean highest concentrations for 24-h, daytime and nighttime sampling periods when compared to those of the other metallic elements (Ni, Cu, Zn and Cd). The average mean highest metallic Pb concentrations in PM10 were 110.7, 203.0 and 207.2 ng/m 3 for 24-h, daytime and nighttime sampling periods in this study. And there were 59.53, 105.2 and 106.6 ng/m 3 for Pb in PM2.5 for 24-h, daytime and nighttime sampling periods, respectively. Moreover, the results further indicated that mean metallic element Pb concentrations on PM 2.5 and PM 10 were all higher than those of the other elements for 24 h, day and nighttime.

  2. Bioavailability of Pb, Zn, Cu, Cd, Ni and Cr in the sediments of the Tessa River: A mining area in the North-West Tunisia

    Science.gov (United States)

    Sebei, Abdelaziz; Helali, Mohamed Amine; Oueslati, Walid; Abdelmalek-Babbou, Chiraz; Chaabani, Fredj

    2018-01-01

    Tessa River is seen as one of the important rivers in Tunisia. Its catchment is known for its agricultural and mining activities, especially the Bougrine and Fedj Lahdhoum mines. Eighteen (18) surface sediments and five (5) water samples were collected from the Tessa River, near these two mining sites. Sediments are essentially sandy (>80%), the most important mineral is quartz (20-73%), then calcite (41%) and dolomites (4%). Heavy metal contents are relatively high near the mining sites, 356 μg g-1 for Pb, 3000 μg g-1 for Zn, and 5 μg g-1 for Cd. These values are lower downstream due to watercourse dilution effects. Other heavy metals: Cu, Ni and Cr, are low, and values are relatively constant in all the studied samples, even near the mining sites. The metals originate from natural sources and not from mining activities. This trend is confirmed by the enrichment factor (EF) where EFNi, EFCu and EFCr are lower or equal to 1, unlike EFPb, EFZn or EFCd where values are much higher (>20). Chemical speciation of these metals does not show any spatial variation. Except for cadmium which is bound to the residual fraction and in the carbonates; all other heavy metals are bound to the five sediment chemical fractions: the residual fraction (>52%), followed by the oxyhydroxides fraction (21%) and carbonates (16%), and finally bound to the organic matter and to the exchangeable fraction (bioavailable fraction of the studied heavy metals exceeds 45%, which present risk of toxicity.

  3. 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.

  4. 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.

  5. Distribution of POC, PON and particulate Al, Cd, Cr, Cu, Pb, Ti, Zn and δ13C in the English Channel and adjacent areas

    International Nuclear Information System (INIS)

    Dauby, P.; Frankignoulle, M.; Gobert, S.; Bouquegneau, J.M.

    1994-01-01

    A study of the spatial distribution of the total suspended matter and of its elemental composition (C, N and trace metals) has been performed in the English Channel. The Celtic Sea, and the Southern Bight of the North Sea in June and October 1991. South-west to north-east gradients of suspended matter mass and of lithogenic components (Ti an Al) linked to riverine inputs and to depth shallowing, are observed; organic carbon and nitrogen display an opposite distribution pattern and reach a maximum in the Biscay oceanic waters. Cu, Pb and Zn concentrations are highest near industrialized areas and large estuaries, showing the importance of river inputs. In contrast, Cd, Cu and Cr concentrations are markedly elevated in organic-rich suspended matter from waters in which suspended matter loadings are low, suggesting a significant biological uptake. Finally, 13 C/ 12 C analyses reveal the relative importance of coastal or continental inputs in the north-eastern Channel and in the North Sea. (authors). 56 refs., 12 figs., 3 tabs

  6. The Survey and Measurement of Ni, Pb, Cu, Mn, Zn, Cd and V Content in Green Vegetables of South Area of Tehran Refinery

    International Nuclear Information System (INIS)

    Kazemzadeh Khoyi, J.; Noori, A. S.; Pourang, N.; Alizadeh, M.; Ghoreishi, H.; Padash, A.

    2013-01-01

    Oil pollution is one of the most critical soil and water pollutant. Areas which are subjected to oil industry may have this kind of pollution by different ways such as extraction, transformation and refining. The example of these areas is south east of Tehran refinery which is surrounded by agricultural fields and are subjected by pollution via Tehran refinery, oil transforming lines, waste water and industrial activities. Since the crops from this area is providing the needs of neighbor cities like Tehran, to realize their oil pollution, the content of some heavy metals like Ni, V, Cu, Cd, Zn, Pb and Mn has been measured. The results analyzed by analytical method include SPSS and MVSP. Finally the relation between elements and pollution has been recognized. The result of this survey showed the high heavy metal content in most plants which were higher than similar research. Onion had the highest amount of most heavy metals. Ni and Pd content were high in plants which are indicator of oil pollution.

  7. Influence of fly ash aided phytostabilisation of Pb, Cd and Zn highly contaminated soils on Lolium perenne and Trifolium repens metal transfer and physiological stress

    International Nuclear Information System (INIS)

    Lopareva-Pohu, Alena; Verdin, Anthony; Garcon, Guillaume; Lounes-Hadj Sahraoui, Anissa; Pourrut, Bertrand; Debiane, Djouher; Waterlot, Christophe; Laruelle, Frederic

    2011-01-01

    Due to anthropogenic activities, large extends of soils are highly contaminated by Metal Trace Element (MTE). Aided phytostabilisation aims to establish a vegetation cover in order to promote in situ immobilisation of trace elements by combining the use of metal-tolerant plants and inexpensive mineral or organic soil amendments. Eight years after Coal Fly Ash (CFA) soil amendment, MTE bioavailability and uptake by two plants, Lolium perenne and Trifolium repens, were evaluated, as some biological markers reflecting physiological stress. Results showed that the two plant species under study were suitable to reduce the mobility and the availability of these elements. Moreover, the plant growth was better on CFA amended MTE-contaminated soils, and the plant sensitivity to MTE-induced physiological stress, as studied through photosynthetic pigment contents and oxidative damage was lower or similar. In conclusion, these results supported the usefulness of aided phytostabilisation of MTE-highly contaminated soils. - Highlights: → Aided phytostabilisation aims to establish a vegetation cover in order to promote immobilisation of MTE. → 8 years after the soil amendments, a pot culture study was carried out in greenhouse conditions. → MTE bioavailability and uptake by the two plants was drastically decreased with amendments. → Our results support the usefulness of aided phytostabilisation of MTE-highly contaminated soils. → CFA addition contributed to the reduction of the MTE mobility and availability for the plants. - Efficiency of Coal Fly Ash amendment for phytostabilisation of Pb, Cd and Zn in MTE-highly contaminated soils.

  8. Study on the application of electrothermal atomization atomic absorption spectrometry for the determination of metallic Cu, Pb, Zn, Cd traces in sea water samples

    International Nuclear Information System (INIS)

    Nguyen Thi Kim Dung; Doan Thanh Son; Tran Thi Ngoc Diep

    2004-01-01

    The trace amount of some heavy metallic elements (Cu, Zn, Pb, Cd) in sea water samples were determined directly (without separation) and quantitatively by using Electro-Thermal Atomization Atomic Absorption Spectrometry (ETA-AAS). The effect of mainly major constituents such as Na, Mg, Ca, K, and the mutual effect of the trace elements, which were present in the matrix on the absorption intensity of each analyzed element was studied. The adding of a certain chemical modification for each trace element was also investigated in order to eliminate the overall effect of the background during the pyrolysis and atomization. The sea water sample after fitrating through a membrane with 0.45 μm-hole size was injected in to the graphite tube via an autosampler (MPE50). The absorption intensity of each element was then measured on the VARIO-6 under the optimum parameters for spectrometer such as: maximum wavelength, current of hollow cathode lamp, and that for graphite furnace such as dry temperature, pyrolysis temperature, atomization temperature, ect. The analytical procedures were set-up and applied for the determination of these above mentioned elements in the synthesized sea water sample and in the real sea water samples with high precision and accuracy. (author)

  9. Evaluation of heavy metals (Cr, Fe, Ni, Cu, Zn, Cd, Pb and Hg) in water, sediments and water lily (Eichornia crassipes) from Jose Antonio Alzate dam; Evaluacion de metales pesados Cr, Fe, Ni, Cu, Zn, Cd, Pb y Hg en agua, sedimento y lirio acuatico (Eichhornia crassipes) de la Presa Jose Antonio Alzate, Estado de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Avila P, P

    1996-12-31

    Water, sediments and water lily (Eichornia crassipes) from the Jose Antonio Alzate Dam were analyzed in order to determine concentrations of chromium, iron, nickel, copper, zinc, cadmium, lead and mercury. Mercury, lead, chromium and iron were found in concentrations above permissible limits in water, and in high concentrations in sediments. Cadmium, nickel, copper and zinc never were found in concentrations above permissible limits in water. The highest concentrations of heavy metals in water lily were found in the root. Accumulation factors decreased in the following order: Zn> Cr> Fe> Ni> Cu> Pb> Hg and Cd. Statistical differences ({alpha} < 0.5) between the collection samples dates was observed. High correlations between metals concentrations in superficial water, sediment and water hyacinth were also observed. These correlations could indicate that the heavy metals studied here, are originated from a natural source such as sediments or from an industrial source. (Author).

  10. Analysis Of Non-Volatile Toxic Heavy Metals (Cd, Pb, Cu,Cr And Zn In ALLIUM SATIVUM (Garlic And Soil Samples ,Collected From Different Locations Of Punjab, Pakistan By Atomic Absorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Ata S.

    2013-04-01

    Full Text Available Garlic is one of the most widely used medicinal plants. The monitoring of toxic metals such as lead, Cadmium, Chromium, Copper and Zinc in garlic and the soil of garlic fields collected from ten different cities of Punjab is critical for preventing public health against the hazards of metal toxicity. The levels of toxic heavy metals in garlic and soil samples were investigated using Atomic absorption spectrometer. The metal content in garlic samples was found to be in increasing order as Cr> Pb> Cd> Cu> Zn. Infield metal content in the soil also followed the same trend. In garlic samples, Pb, Cd, Cr, Zn and Cu ranged from 0.039mg/L to 0.757mg/L, N.D to 1.211mg/L, 0.03mg/L to 0.451mg/L, 0.02mg/Lto0.42mg/L and 0.451mg/L to 0.893mg/L respectively. In soil samples, Pb, Cd, Cr, Zn and Cu were ranged from 0.459mg/L to 0.797mg/L, 0.205mg/L to1.062mg/L, 0.074mg/L to 2.598mg/L, 0.124mg/L to 0.276mg/L and 0.494mg/L to 0.921mg/L respectively. In our study, the Pb and Cd was found more in garlic from Gujranwala and Jaranwala, Cu and Zn were more in samples from Kasur while Cr was predominant in sample from Sheikhupura. Heavy metal content in soil and garlic samples was within the permissible limits proposed by World Health Organization (WHO.

  11. Effects of heavy metal concentrations (Cd, Zn and Pb) in agricultural soils near different emission sources on quality, accumulation and food safety in soybean [Glycine max (L.) Merrill

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, Maria Julieta [Multidisciplinary Institute of Plant Biology, Pollution and Bioindicator Section, Faculty of Physical and Natural Sciences, National University of Cordoba, Av. Velez Sarsfield 1611, X5016CGA Cordoba (Argentina); Rodriguez, Judith Hebelen, E-mail: jrodriguez@com.uncor.edu [Multidisciplinary Institute of Plant Biology, Pollution and Bioindicator Section, Faculty of Physical and Natural Sciences, National University of Cordoba, Av. Velez Sarsfield 1611, X5016CGA Cordoba (Argentina); Nieto, Gaston Leonardo; Pignata, Maria Luisa [Multidisciplinary Institute of Plant Biology, Pollution and Bioindicator Section, Faculty of Physical and Natural Sciences, National University of Cordoba, Av. Velez Sarsfield 1611, X5016CGA Cordoba (Argentina)

    2012-09-30

    Highlights: Black-Right-Pointing-Pointer Soybean grown near metal sources presents a toxicological hazard from heavy metals for Chinese consumers. Black-Right-Pointing-Pointer Rhizosphere soil is the most suitable compartment for toxicological studies. Black-Right-Pointing-Pointer Soil guidelines should be modified considering the exchangeable metals. - Abstract: Argentina is one of the major producers of soybean in the world, this generates a high global demand for this crop leading to find it everywhere, even close to human activities involving pollutant emissions. This study evaluated heavy metal content, the transfer of metals and its relation to crop quality, and the toxicological risk of seed consumption, through soil and soybean sampling. The results show that concentrations of Pb and Cd in soils and soybeans at several sites were above the maximum permissible levels. The heavy metal bioaccumulation depending on the rhizosphere soil compartment showed significant and high regression coefficients. In addition, the similar behavior of Cd and Zn accumulation by plants reinforces the theory of other studies indicating that these metals are incorporated into the plant for a common system of transport. On the other hand, the seed quality parameters did not show a clear pattern of response to metal bioacumulation. Taken together, our results show that soybeans grown nearby to anthropic emission sources might represent a toxicological hazard for human consumption in a potential Chinese consumer. Hence, further studies should be carried out taking into account the potential negative health effects from the consumption of soybeans (direct or indirect through consumption of meat from cattle) in these conditions.

  12. Qualitative analysis of As, Ba, Cd, Cr, Zn, Fe, Mn, K, Hg, Pb y Cu, as constituents of Amatitlan Lake sediment by XRF

    International Nuclear Information System (INIS)

    Beltran, P.A.E.; Morales, E.A.

    1987-10-01

    Samples of fifteen sampling points were analyzed. Molybdenum X-ray tube with secondary excitation assembly, SiLi detector and deconvolution software AXIL were employed; self-standardization method based upon incoherent ratio was used for quantitative analysis of some elements. Ca, P, S, Ti, Mn, Fe, Cr, Zn, Cu, Ni, Ga, As, Pb, Ge, Sr and Pb, were found. As, Pb and Cu concentrations lower than 109 mg/lt, 119 mg/lt, and 500mg/lt, respectively, were measured. Hg was not detected. (author)

  13. Liquidus surface of the triple reciprocal system PbTe+CdS↔PbS+CdTe

    International Nuclear Information System (INIS)

    Tomashik, Z.F.; Tomashik, V.N.

    1987-01-01

    Using differential-thermal and microstructural analyses and mathematical design interaction in PbTe-CdS system is studied. Liquidus surface of the triple reciprocal system PbTe+CdS↔PbS+CdTe is plotted. It is shown that PbTe-CdS system phase diagram is of eutectic type. Maximal solubility of CdS in PbTe attains 13 mol%, and of PbTe in CdS is not over 1 mol%. Projection of liquidus surface of the PbTe+CdS↔PbS+CdTe triple reciprocal system consists of two primary crystallization fields: CdTe x S 1-x and PbTe x S 1-x solid solutions separated by eutectic line

  14. Stormwater induced input of Pb, Cd, As, Zn and other toxic heavy metals into the sewer system of a region characterized by mining residues. Final report

    International Nuclear Information System (INIS)

    Cichos, C.; Muehle, K.

    1993-06-01

    An estimation of heavy metal transport within the river Freiberger Mulde as well as detailed knowledge about pollutant concentration in sewage sludges, in surface soil and in various mining residues give rise to assume that stormwater induced input especially of As, Pb, Cd and Zn into the sewer system of the town of Freiberg has a significant share of contribution to the high pollution of the river. It is the aim of the project to determine the heavy metal input quantitatively where beside the entire transport above all the main transport ways are to be investigated. In the first period of research reported about a movable monitoring station with rainfall gauge, flow rate meter and automatic sampler had to be supplied. First results of stormwater effects at the main intercepting sewer were discussed on the basis of dry-wether flow. For precipitation intensities of 0.5-1 mm/10 min with 4 to 5fold discharge rates at the maximum the measurements showed about 2 to 6fold dry-wether diurnal loads during a rain wether flow of only one hour. Thus, for the case of flood flow up to 100fold diurnal loads may be expected within an hour. The pollutant transport depends on the intensity of rain and on the duration of dry wether before the rain. Further studies above all apply to the main ways of transport but simultaneously to the entire loads to be measured before the storm sewage overflow. Data to be expected in this way may contribute to a long-term simulation of the sewerage as an important aid for planning storage basins. (orig.) [de

  15. 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.

  16. 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.

  17. Structural and luminescence studies of Eu3+: TeO2sbnd B2O3sbnd AOsbnd AF2 (A = Pb, Ba, Zn, Cd, Sr) glasses

    Science.gov (United States)

    Selvi, S.; Marimuthu, K.; Muralidharan, G.

    2017-09-01

    Eu3+ doped oxyfluoro boro-tellurite (TBXFE) with molar composition 29 TeO2sbnd 30B2O3sbnd 20AOsbnd 20AF2sbnd 1Eu2O3 (where A = Pb, Ba, Zn, Cd, Sr) glasses were prepared and investigated by XRD, FTIR, UV-Vis-NIR, luminescence and decay measurements. XRD patterns confirm the glassy nature of the prepared glasses. The influence of metal ions on the structure of boro-tellurite glasses were investigated through FTIR spectra. The intra band (4f-4f) transitions of Eu3+ ions are discussed through UV-Vis-NIR absorption spectra. The covalent nature around the Eu3+ ions with ligands are discussed using the bonding parameter (δ) and nephelauxetic ratio (β). The fundamental absorption edge, direct, indirect band gap, Urbach energy and band tailing parameters are reported. A bright red emission at 616 nm corresponding to the 5D0 → 7F2 transition of Eu3+ ions could be observed in the title glasses. Judd-Ofelt parameters were estimated from the emission spectra of Eu3+ ions. The dependence of these parameters on the composition of the glass is discussed. Judd-Ofelt parameters were used to derive the radiative parameters such as transition probabilities (A, s-1), branching ratios (βR), radiative lifetime (τrad) and stimulated emission cross-section (σPE) for the 5D0 → 7FJ (J = 0, 1, 2, 3 and 4) transitions. The luminescence intensity ratio (LIR) of 5D0 → 7F2/5D0 → 7F1 transitions was estimated to analyze the local site symmetry around the Eu3+ ions in the present glasses. The chromaticity coordinates and colour purity were calculated from the emission spectra and analyzed with Commission International de I'Eclairage (CIE) 1931 diagram. The experimental lifetime of 5D0 level could be fitted to a single exponential indicating the absence of energy transfer between the Eu3+ ions in the present glasses.

  18. Etude d’impact des métaux traces (Hg, Cd, Pb, Cu et Zn) dans les cystes et la biomasse "d’Artemia" exploités dans la saline de Sfax

    OpenAIRE

    Aloui, N.; Amorri, M.; Choub., L.

    2010-01-01

    RESUME La saline de Sfax constitue un site potentiel pour l’exploitation et la production de l’Artemia locale. Des quantités importantes d’Artemia sont exploitées chaque année (60 kg de cystes poids sec) et sont utilisées en alimentation larvaire. Afin de démontrer l’impact de divers rejets industriels, agricoles dans cette saline, nous avons procédé à la détermination de quelques métaux traces toxiques : le mercure (Hg), le cadmium (Cd), le plomb (Pb), le cuivre (Cu) et le zinc (Zn) p...

  19. Distribution and accumulation of Cd, Cu, Hg, Pb and Zn in the surface sediments of El Tobari Lagoon, central-East Gulf of California: An ecosystem associated with agriculture and aquaculture activities.

    Science.gov (United States)

    Jara-Marini, M E; Tapia-Alcaraz, J N; Dumer-Gutiérrez, J A; García-Rico, L; García-Hernández, J; Páez-Osuna, F

    2013-01-01

    The purpose of this research is to provide a comprehensive assessment of the concentration levels and spatial variability of cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb) and zinc (Zn) in El Tobari Lagoon in surface sediments during two seasons for several geochemical variables that could explain the observed heavy metal variability. Seventy-two surface sediments samples were collected in 12 different sites of the El Tobari Lagoon. Sediment samples were dried and subjected to acid extraction using a microwave system and five metals (Cd, Cu, Hg, Pb and Zn) were measured using atomic adsorption spectrometry. A certificate sediment material and blanks were used as quality control purposes. The enrichment factor (EF) and the index of geoaccumulation (Igeo) were calculated as index of metals contamination for the sediments, using aluminum as the conservative element. The five metals examined in sediments from El Tobari Lagoon exhibited a linear correlation with Al as result of the large specific surface areas of these sediment components and the chemical affinities between them. The metals contents in sites of the El Tobari Lagoon were variable, and Cd, Cu and Hg presented a seasonal behavior. The enrichment factor and index of geoaccumulation analysis indicated that Cd and Hg exhibited a certain extent (EF for Cd ranged from 4.10 to 10.29; EF for Hg ranged from 2.77 to 12.89) of anthropogenic pollution, while Cu showed sporadic (EF ranged from 0.43 to 2.54) anthropogenic contamination. The highest concentrations of Cd, Cu and Hg were found in the sites that regularly received discharge effluents from agriculture and aquaculture.

  20. Assessment of soil contamination by potentially toxic trace elements (PTSD) (As, Cd, Cu, Hg, Pb, Zn) in a lower plain of the Hron River according to Law no. 219/2008 Coll., by geo-accumulation index, anthropogenic factor and Tomlinson index; Zhodnotenie kontaminacie pod potencialne toxickymi stopovymi prvkami (PTSP) (As, Cd, Cu, Hg, Pb, Zn) v dolnej casti nivy Hrona podla zakona c. 219/2008 Z.z., indexu geoakumulacie, antropogenneho faktora a Tomlinsonovho indexu

    Energy Technology Data Exchange (ETDEWEB)

    Hlodak, M [Univerzita Komenskeho v Bratislave, Prirodovedecka fakulta, Ustav laboratorneho vyskumu geomaterialov, 84215 Bratislava (Slovakia)

    2012-04-25

    Soil contamination by different PTSD may have different geogenic and anthropogenic origin and occurs in all countries of the world. The aim of this paper is to evaluate the soils contamination of a lower plain of the Hron River. This paper used the results of the thesis Soil contamination of the Hron River floodplain by trace elements (As, Cd, Cu, Hg, Pb, Zn) [1]. Soil contamination was evaluated by: Act. 219/2008 Coll. on the protection and use of agricultural land, by anthropogenic factor (AF), geo-accumulation index (IgeoE) and Tomlinson index - the index of the pollution load (PLI). (author)

  1. Genotoxicity and cytotoxicity response to environmentally relevant complex metal mixture (Zn, Cu, Ni, Cr, Pb, Cd) accumulated in Atlantic salmon (Salmo salar). Part I: importance of exposure time and tissue dependence.

    Science.gov (United States)

    Stankevičiūtė, Milda; Sauliutė, Gintarė; Svecevičius, Gintaras; Kazlauskienė, Nijolė; Baršienė, Janina

    2017-10-01

    Health impact of metal mixture at environment realistic concentrations are difficult to predict especially for long-term effects where cause-and-effect relationships may not be directly obvious. This study was aimed to evaluate metal mixture (Zn-0.1, Cu-0.01, Ni-0.01, Cr-0.01, Pb-0.005 and Cd-0.005 mg/L, respectively for 1, 2, 4, 7, 14 and 28 days at concentrations accepted for the inland waters in EU) genotoxicity (micronuclei, nuclear buds, nuclear buds on filament), cytotoxicity (8-shaped nuclei, fragmented-apoptotic erythrocytes), bioaccumulation, steady-state and the reference level of geno-cytotoxicity in hatchery-reared Atlantic salmon tissues. Metals accumulated mostly in gills and kidneys, to the lesser extent in the muscle. Uptake of metals from an entire mixture in the fish for 14 days is sufficient to reach steady-state Cr, Pb concentrations in all tissues; Zn, Cu-in kidneys and muscle, Ni-in liver, kidneys, muscle and Cd-in muscle. Treatment with metal mixture significantly increased summed genotoxicity levels at 7 days of exposure in peripheral blood and liver erythrocytes, at 14 days of exposure in gills and kidney erythrocytes. Significant elevation of cytotoxicity was detected after 2 and 14 days of exposure in gills erythrocytes and after 28 days-in peripheral blood erythrocytes. The amount of Cu, Cr, Pb and Cd accumulated in tissues was dependent upon duration of exposure; nuclear buds, 8-shaped nuclei frequencies also were dependent upon duration of exposure. This study indicates that metals at low levels when existing in mixture causes significant geno-cytotoxicity responses and metals bioaccumulation in salmon.

  2. 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.

  3. 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

    International Nuclear Information System (INIS)

    Nomngongo, Philiswa N.; Ngila, J. Catherine

    2014-01-01

    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 −1 , n = 15), limits of detection and quantification ranged from 0.1 to 0.3 μg L −1 and 0.3–0.9 μg L −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

  4. Adsorption of Pb(II), Cu(II), Cd(II), Zn(II), Ni(II), Fe(II), and As(V) on bacterially produced metal sulfides.

    Science.gov (United States)

    Jong, Tony; Parry, David L

    2004-07-01

    The adsorption of Pb(II), Cu(II), Cd(II), Zn(II), Ni(II), Fe(II) and As(V) onto bacterially produced metal sulfide (BPMS) material was investigated using a batch equilibrium method. It was found that the sulfide material had adsorptive properties comparable with those of other adsorbents with respect to the specific uptake of a range of metals and, the levels to which dissolved metal concentrations in solution can be reduced. The percentage of adsorption increased with increasing pH and adsorbent dose, but decreased with increasing initial dissolved metal concentration. The pH of the solution was the most important parameter controlling adsorption of Cd(II), Cu(II), Fe(II), Ni(II), Pb(II), Zn(II), and As(V) by BPMS. The adsorption data were successfully modeled using the Langmuir adsorption isotherm. Desorption experiments showed that the reversibility of adsorption was low, suggesting high-affinity adsorption governed by chemisorption. The mechanism of adsorption for the divalent metals was thought to be the formation of strong, inner-sphere complexes involving surface hydroxyl groups. However, the mechanism for the adsorption of As(V) by BPMS appears to be distinct from that of surface hydroxyl exchange. These results have important implications to the management of metal sulfide sludge produced by bacterial sulfate reduction.

  5. 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

  6. Comparison of trace element contamination levels (Cu, Zn, Fe, Cd ...

    African Journals Online (AJOL)

    Comparison of trace element contamination levels (Cu, Zn, Fe, Cd and Pb) in the soft tissues of the gastropods Tympanotonus fuscatus fuscatus and Tf radula collected in the Ebrié Lagoon (Côte d'Ivoire): Evidence of the risks linked to linked to lead and.

  7. Comparison of trace element contamination levels (Cu, Zn, Fe, Cd ...

    African Journals Online (AJOL)

    SERVER

    2008-03-18

    Mar 18, 2008 ... Chemical analysis of the trace elements in the soft tissues. The trace elements of interest (Cu, Zn, Fe, Pb, Cd) were then determined in the digested solutions, using Thermoelemental type. M6 brand of an atomic absorption Spectrometer equipped with a flame operated atomisation system and a deuterium ...

  8. Measurements of labile Cd, Cu, Ni, Pb, and Zn levels at a northeastern Brazilian coastal area under the influence of oil production with diffusive gradients in thin films technique (DGT).

    Science.gov (United States)

    de Souza, João M; Menegário, Amauri A; de Araújo Júnior, Marcus A G; Francioni, Eleine

    2014-12-01

    In this work, the ability of the diffusive gradients in thin films technique (DGT) was evaluated for monitoring the concentrations, and estimating the availability, of metals at a northeastern Brazilian coastal area under the influence of oil production. Three sites with an average distance between 0m (EM-1), 100 m (EM-2), and 1,000 m (EM-3) of a submarine outfall-I (Guamaré-RN, Brazil) and another site (GA-1) with an average distance of 12,000 m east of Outfall I, near the city of Galinhos, were studied. DGT units were deployed at the same sites in three campaigns from July, 2010 to June, 2011. Effects on the accuracy of analytical results regarding the deployment time, gel porosity, and thickness were evaluated. There was no difference between the measurements obtained with two sets of DGT devices, those assembled with open or restrictive pore gel, respectively, showing that organic metallic species are not present near the submarine outlet. After 21 day deployments in a region (near Submarine Outfall I) that receives produced waters that have been treated, there was evidence of biofilm formation on DGT membranes. However, it was demonstrated that the biofilm interference with DGT measurements was negligible. Data found in this work show that total concentrations of Cd, Cu, Pb, Ni, and Zn in seawater samples collected at sites GA-1 and EM-1 in two campaigns were below 0.33, 1.67, 0.47, 0.70, 2.86 ng mL(-1) respectively. For the first time, labile levels of Cd, Cu, Pb, Ni, and Zn in an area under the influence of oil production were determined. DGT measurements allowed the verification of the effects of temporal variation on levels of Zn and Ni. There were no effects of spatial variations on levels of Cd, Cu, Ni, Pb, and Zn at the four studied sites, suggesting no contamination of these metals at the northeastern Brazilian coastal area investigated in this work. Copyright © 2014. Published by Elsevier B.V.

  9. Relations between metals (Zn, Pb, Cd and Cu) and glutathione-dependent detoxifying enzymes in spiders from a heavy metal pollution gradient

    International Nuclear Information System (INIS)

    Wilczek, Grazyna; Babczynska, Agnieszka; Augustyniak, Maria; Migula, Pawel

    2004-01-01

    We studied the relations between glutathione-dependent detoxifying enzymes and heavy metal burdens in the web-building spider Agelena labyrinthica (Agelenidae) and the wolf spider Pardosa lugubris (Lycosidae) from five meadow sites along a heavy metal pollution gradient. We assayed the activity of glutathione-S-transferase (GST) and glutathione peroxidases (GPOX, GSTPx), and glutathione (GSH) levels in both sexes. Except for GSH vs Pb content, we found significant correlations between GPOX and GSTPx activity and metal concentrations in females of A. labyrinthica. The highest activity of these enzymes measured in the web-building spiders was found in the individuals from the most polluted sites. In P. lugubris males significant correlations were found between GST and Pb and Zn concentrations, and between GPOX and GSTPx and the concentration of Cu. GST activity was higher in males collected from less polluted areas. Thus, detoxifying strategies against pollutants seemed to be sex-dependent. Actively hunting spiders had higher metal concentrations, maintaining lower activity of detoxifying enzymes and a lower glutathione level. - Capsule: Glutathione-linked enzyme activity in spiders from polluted areas depends on hunting strategy and sex

  10. Relations between metals (Zn, Pb, Cd and Cu) and glutathione-dependent detoxifying enzymes in spiders from a heavy metal pollution gradient

    Energy Technology Data Exchange (ETDEWEB)

    Wilczek, Grazyna [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Babczynska, Agnieszka [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Augustyniak, Maria [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Migula, Pawel [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland)]. E-mail: migula@us.edu.pl

    2004-12-01

    We studied the relations between glutathione-dependent detoxifying enzymes and heavy metal burdens in the web-building spider Agelena labyrinthica (Agelenidae) and the wolf spider Pardosa lugubris (Lycosidae) from five meadow sites along a heavy metal pollution gradient. We assayed the activity of glutathione-S-transferase (GST) and glutathione peroxidases (GPOX, GSTPx), and glutathione (GSH) levels in both sexes. Except for GSH vs Pb content, we found significant correlations between GPOX and GSTPx activity and metal concentrations in females of A. labyrinthica. The highest activity of these enzymes measured in the web-building spiders was found in the individuals from the most polluted sites. In P. lugubris males significant correlations were found between GST and Pb and Zn concentrations, and between GPOX and GSTPx and the concentration of Cu. GST activity was higher in males collected from less polluted areas. Thus, detoxifying strategies against pollutants seemed to be sex-dependent. Actively hunting spiders had higher metal concentrations, maintaining lower activity of detoxifying enzymes and a lower glutathione level. - Capsule: Glutathione-linked enzyme activity in spiders from polluted areas depends on hunting strategy and sex.

  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.

    2014-12-01

    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 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

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Zhaochuan; Vlugt, Thijs J. H., E-mail: t.j.h.vlugt@tudelft.nl [Process and Energy Department, Delft University of Technology, Leeghwaterstraat 39, 2628 CB Delft,The Netherlands (Netherlands); Koster, Rik S.; Fang, Changming; Huis, Marijn A. van [Debye Institute for Nanomaterials Science and Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, 3584 CC Utrecht (Netherlands); Wang, Shuaiwei [Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou, Henan 450006 (China); Yalcin, Anil O.; Tichelaar, Frans D.; Zandbergen, Henny W. [Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands)

    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.

  13. 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.

  14. Responses of different water spinach cultivars and their hybrid to Cd, Pb and Cd-Pb exposures.

    Science.gov (United States)

    Xin, Junliang; Huang, Baifei; Yang, Zhongyi; Yuan, Jiangang; Dai, Hongwen; Qiu, Qiu

    2010-03-15

    A pot experiment was conducted to investigate the stability of Cd and/or Pb accumulation in shoot of Cd and Pb pollution-safe cultivars (PSCs), the hereditary pattern of shoot Cd accumulation, and the transfer potentials of Cd and Pb in water spinach (Ipomoea aquatica Forsk.). A typical Cd-PSC, a typical non-Cd-PSC (Cd accumulative cultivar), a hybrid from the former two cultivars, and two typical Cd+Pb-PSCs were grown in seven soils with different concentrations of Cd and Pb. The results showed that concentrations of Cd and Pb in shoot of the PSCs were always lower than the non-PSC and the highest Cd and Pb transfer factors were also always observed in the non-PSC, indicating the stability of the PSCs in Cd and Pb accumulation. Shoot Cd concentration seemed to be controlled by high Cd dominant gene(s) and thus crossbreeding might not minimize Cd accumulation in water spinach. Interaction between Cd and Pb in soils affected the accumulations of the metals in shoot of water spinach. Under middle Cd and Pb treatments, the presence of higher Pb promoted the accumulation of Cd. However, under high Pb treatment, accumulations of Cd and Pb were both restricted. (c) 2009 Elsevier B.V. All rights reserved.

  15. Suitability of three cultivars of coral bells (heuchera cvs. to bioremediation of cadmium (cd, lead (pb and zinc (zn from post-mining area in zagłębie dąbrowskie

    Directory of Open Access Journals (Sweden)

    Gabriela Sąkol

    2011-09-01

    Full Text Available Background: Long-term shallow exploitation of pitcoal in Będzin area (in mining district Zagłębie Dąbrowskie has degraded the environment. Profiles of soil were dislocated and contaminated with heavy metals above permissible standards. Due to the fact that Zagłę- bie Dąbrowskie is densely populated, risk of harmful exposure to heavy metals affects high number of people. Decontamination of post-mining grounds is possible with planting plants which not only tolerate elevated heavy metals quantities but can also accumulate them in plant tissues. Materials and methods: The cultivars ‘Chatterbox’ and ‘Strawberry Swirl’ and ‘Palace Purple’ of coral bells (Heuchera cvs. were chosen to do the research. Cadmium, lead and zinc uptake in plants growing in contaminated and control fields was evaluated. Amount of heavy metals was determined by atomic absorption spectrometry (AAS. Results: Content of metals detected in plants in postmining soil was respectively: Cd 1,92 mgükg11, Pb 56,3 mgükg11, Zn 153,7 mgükg11. Those metals value is from 2 to 4 times higher than natural content in neutral soil of pH 6,5 – a typical pH in this region. The examined cultivars of coral bells accumulated significant amount of Cd, Pb, Zn even if concentration of those metals was low, what is characteristic for clean regions of Poland. Conclusions: The plants cultivated on contaminated soil of post-mining region didn`t show toxic response (damaged leaves even though they accumulated cadmium, lead and zinc in their roots and leaves. Cultivars differences of coral bells found on significance level (p¤0,05. The cultivar ‘Palace Purple’ has transported the highest amount of lead from roots to leaves. Other cultivars ‘Chatterbox’ and ‘Strawberry Swirl’ have accumulated higher amounts of metals in their roots in a sequence Cd¤Zn¤Pb.

  16. Band alignment of type I at (100ZnTe/PbSe interface

    Directory of Open Access Journals (Sweden)

    Igor Konovalov

    2016-06-01

    Full Text Available A junction of lattice-matched cubic semiconductors ZnTe and PbSe results in a band alignment of type I so that the narrow band gap of PbSe is completely within the wider band gap of ZnTe. The valence band offset of 0.27 eV was found, representing a minor barrier during injection of holes from PbSe into ZnTe. Simple linear extrapolation of the valence band edge results in a smaller calculated band offset, but a more elaborate square root approximation was used instead, which accounts for parabolic bands. PbSe was electrodeposited at room temperature with and without Cd2+ ions in the electrolyte. Although Cd adsorbs at the surface, the presence of Cd in the electrolyte does not influence the band offset.

  17. 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%. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. 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.

  19. 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.

  20. Synthesis of high-surface-area γ-Al2O3 from aluminum scrap and its use for the adsorption of metals: Pb(II), Cd(II) and Zn(II)

    International Nuclear Information System (INIS)

    Asencios, Yvan J.O.; Sun-Kou, María R.

    2012-01-01

    Highlights: ► Aluminum hydroxide obtained from aluminum scrap led to the formation of gamma alumina. ► Acidic pH of precipitation favored the formation of small particles of high surface areas. ► Higher aging temperature favored the formation of large structures of large pore sizes. ► Higher aging temperature generated symmetrical solids of regular hexagonal prism forms. ► Aluminas of large pores adsorbed metals as following: Pb (1.75 Å) > Cd (1.54 Å) > Zn (1.38 Å). - Abstract: Several types of alumina were synthesized from sodium aluminate (NaAlO 2 ) by precipitation with sulfuric acid (H 2 SO 4 ) and subsequently calcination at 500 °C to obtain γ-Al 2 O 3 . The precursor aluminate was derived from aluminum scrap. The various γ-Al 2 O 3 synthesized were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), adsorption–desorption of N 2 (S BET ) and scanning electron microscopy (SEM). XRD revealed that distinct phases of Al 2 O 3 were formed during thermal treatment. Moreover, it was observed that conditions of synthesis (pH, aging time and temperature) strongly affect the physicochemical properties of the alumina. A high-surface-area alumina (371 m 2 g −1 ) was synthesized under mild conditions, from inexpensive raw materials. These aluminas were tested for the adsorption of Cd(II), Zn(II) and Pb(II) from aqueous solution at toxic metal concentrations, and isotherms were determined.

  1. Spatial distribution and biological effects of trace metals (Cu, Zn, Pb, Cd) and organic micropollutants (PCBs, PAHs) in mussels Mytilus galloprovincialis along the Algerian west coast.

    Science.gov (United States)

    Benali, Imene; Boutiba, Zitouni; Grandjean, Dominique; de Alencastro, Luiz Felippe; Rouane-Hacene, Omar; Chèvre, Nathalie

    2017-02-15

    Native mussels Mytilus galloprovincialis are used as bioindicator organisms to assess the concentration levels and toxic effects of persistent chemicals, polychlorobiphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and heavy metals using biomarker responses, such as catalase (CAT), glutathione s-transferase (GST), and condition indices, for the Algerian coast. The results show that mussels of Oran Harbour are extremely polluted by PCBs and PAHs, i.e., 97.6 and 2892.1μg/kg d.w., respectively. Other sites present low levels of pollution. Furthermore, high concentrations of zinc, lead and cadmium are found in mussels from fishing, agricultural and estuarine sites, respectively, while low concentrations of copper are found in all of the sites studied. CAT activity is negatively correlated with Cd and Cu, and Zn is positively correlated with GST and CAT. Site classification tools reveal the potential toxicity of coastal areas exposed to anthropogenic pressure and a gradient of toxicity along the Algerian west coast. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Immobilization of Cd, Zn, and Pb from Soil Treated by Limestone with Variation of pH Using a Column Test

    Directory of Open Access Journals (Sweden)

    Sung-Wook Yun

    2015-01-01

    Full Text Available Decades of mining in South Korea have resulted in the contamination of large amounts of soil by metals. The most feasible approach to site restoration requires the use of a stabilization agent to reduce metal mobility. This study examined the leaching characteristics of limestone used as a stabilization agent when subjected to solutions of differing pH. In a laboratory-scale column test, solutions with pH values of 3.5, 4.6, and 5.6, representing acidic to nonacidic rainfall, were applied to soil mixed with limestone. Test results indicate that metal components can be released with the addition of acidic solutions, even if the soil is highly alkaline. Cd and Zn, in particular, exhibited abrupt or continuous leaching when exposed to acid solutions, indicating the potential for contamination of water systems as metal-laden soils are exposed to the slightly acidic rainfall typical of South Korea. Treatment using stabilization agents such as limestone may reduce leaching of metals from the contaminated soil. Stabilizing metal-contaminated farmland is an economical and feasible way to reduce pollutants around abandoned metal mines.

  3. Synthesis and Photocatalytic Activity of Zn Cd S/TiO ...

    African Journals Online (AJOL)

    NICOLAAS

    Synthesis and Photocatalytic Activity of Zn x. Cd. 1–x ... Electrospinning and Hydrothermal Method. Wei Changa,b,* ... conductor composites such as CdS,9 SnO,10 PbS11. .... 280 nm. ZnxCd1–xS nanoparticles grew on the surface of TiO2 with.

  4. Assessment Of Heavy Metal Contamination Of Water Sources From Enyigba Pb-Zn District South Eastern Nigeria

    Directory of Open Access Journals (Sweden)

    Nnabo Paulinus N

    2015-08-01

    Full Text Available Abstract A total of thirty 30 water samples were collected from the Enyigba PbZn mining district to assess the contamination of the water sources as a result of mining of lead and zinc minerals in the area. This comprises of 12 samples of surface water 14 from mine ponds and 4 from underground borehole water. The samples were acidified to stabilize the metals for periods more than four days without the use of refrigeration. The acidified water samples were analysed by a commercial laboratory at Projects Development Institute PRODA Enugu using Atomic Absorption Spectroscopy AAS. The elements determined by this method are lead Pb zinc Zn copper Cu arsenic As cadmium Cd nickel Ni manganese Mn and cobalt Co. The result and analysis of contamination factor showed that in surface water Cd had the highest concentration followed by As and Pb while Ni had the lowest. In mine ponds Cd also had the highest concentration and followed by Pb and As and Ni the lowest. In borehole water Cd has the highest concentration followed by Pb and As while Ni had the lowest concentration. Compared to WHO permissible limits the contamination of the heavy metals in all water sources are in order CdAsPbNiZnCu. In surface water the order is CdAsPbNiZnCu in mine ponds it is CdPbAsNiZnCu and in borehole water the order is CdAsPbZnNiCu. The calculated contamination factors show very high contamination status for Cd Pb and As. These levels of contamination and values indicate that under the prevailing conditions and environmental regulations in Nigeria the mining district would face major and hazardous discharges of these metals to the water sources.

  5. Evolution with time of 12 metals (V, Cr, Mn, Co, Cu, Zn, Ag, Cd, Ba, Pb, Bi and U) and of lead isotopes in the snows of Coats Land (Antarctica) since the 1830's

    International Nuclear Information System (INIS)

    Planchon, F.

    2001-01-01

    This work shows that it is now possible to get reliable data on the occurrence of numerous heavy metals at ultra low levels in Antarctic snow, by combining ultra clean field sampling and laboratory sub-sampling procedures and the use of ultra sensitive analytical techniques such as ICP-SFMS and TIMS. It has allowed us to determine concentrations of twelve metals (V, Cr, Mn, Co, Cu, Zn, Ag, Cd, Ba, Pb, Bi et U) and lead isotopic composition in the ultra clean series of snow samples collected at Coats Land, in the Atlantic sector of Antarctica. This work presents a 150 years record of metal inputs from natural and anthropogenic sources to Antarctica from the 1830's to the early 1990's. Lead atmospheric pollution begins as early as the end of the 19. century, peaks during the 1970's-1980's and then falls sharply during recent decades. Evolution in lead isotopic abundance shows that Pb inputs to Antarctica reflect a complex blend of contributions originating from the Southern part of South America and Australia. For Cr, Cu, Zn, Ag, Bi and U, concentrations in the snow show significant increases from 1950 to 1980. These enhancements which cannot be explained by variations in natural inputs, illustrate that atmospheric pollution for heavy metals linked with anthropogenic activities in the Southern Hemisphere countries such as for example ferrous and non-ferrous metal mining and smelting is really global. Study of the time period 1920-1990, has allowed us to detail short-term (intra and inter annual) heavy metals concentration's changes. The large short-term variability, observed in Coats Land snow, shows the complex patterns of metal inputs to Antarctica, associated for instance to changes in long-range transport processes from mid-latitude to polar zone and to variability in the different natural sources, such local volcanic activity, sea-salt spray or crustal dust inputs. (author)

  6. VALIDACIÓN DE LA METODOLOGÍA PARA LA DETERMINACIÓN DE SB, AS, CD, CU, CR, HG, NI, PB Y ZN EN SEDIMENTOS POR ICO-MS

    Directory of Open Access Journals (Sweden)

    Hermógenes Rosas Rodríguez

    2004-01-01

    Full Text Available En este trabajo se presentan los resultados obtenidos en la validación de la técnica ICP-MS utilizada para la determinación de nueve elementos en sedimentos: Sb, As, Cd, Cu, Cr, Hg, Ni, Pb y Zn. Para ello se llevó a cabo el estudio de los siguientes parámetros de fiabilidad: precisión, exactitud y límites de detección y cuantificación. Para el análisis de estos elementos se utilizó un ICP-MS ELAN 6000 de Perkin Elmer®. El estudio de los distintos parámetros de validación fue muy satisfactorio para la mayoría de los analitos, alcanzándose límites de detección y de cuantificación muy bajos (inferiores a 1microg/l e incluso de 1 ng/l para el Cd. El método ICP-MS es exacto y preciso, obteniéndose para la mayoría de los elementos coeficientes de variación en torno al 2% y porcentajes de recuperación del 100%.

  7. 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

  8. High-Efficiency Photochemical Water Splitting of CdZnS/CdZnSe Nanostructures

    Directory of Open Access Journals (Sweden)

    Chen-I Wang

    2013-01-01

    Full Text Available We have prepared and employed TiO2/CdZnS/CdZnSe electrodes for photochemical water splitting. The TiO2/CdZnS/CdZnSe electrodes consisting of sheet-like CdZnS/CdZnSe nanostructures (8–10 μm in length and 5–8 nm in width were prepared through chemical bath deposition on TiO2 substrates. The TiO2/CdZnS/CdZnSe electrodes have light absorption over the wavelength 400–700 nm and a band gap of 1.87 eV. Upon one sun illumination of 100 mW cm−2, the TiO2/CdZnS/CdZnSe electrodes provide a significant photocurrent density of 9.7 mA cm−2 at −0.9 V versus a saturated calomel electrode (SCE. Incident photon-to-current conversion efficiency (IPCE spectrum of the electrodes displays a maximum IPCE value of 80% at 500 nm. Moreover, the TiO2/CdZnS/CdZnSe electrodes prepared from three different batches provide a remarkable photon-to-hydrogen efficiency of 7.3 ± 0.1% (the rate of the photocatalytically produced H2 by water splitting is about 172.8 mmol·h−1·g−1, which is the most efficient quantum-dots-based photocatalysts used in solar water splitting.

  9. Synthesis and characterization of ZnO/ZnSe NWs/PbS QDs solar cell

    Science.gov (United States)

    Kamruzzaman, M.; Zapien, J. A.

    2017-04-01

    The capture of solar energy has gained the attention for the next generation solar cell. ZnO/ZnSe NW arrays were synthesized on an FTO glass substrate using a simple and facile hydrothermal and ion-exchange approaches. The lead sulfide (PbS) QDs was infiltrated into ZnO/ZnSe NWs via SILAR method for making inorganic quantum dot sensitized ZnO/ZnSe/PbS QDs solar cell. The surface morphology, structural, optical, and J-V characteristics have been investigated. The ZnO/ZnSe NW is a core-shell like structure, and the absorption edge shifted from the UV region (ZnO NWs) to the near infrared region for ZnO/ZnSe NWs/PbS QDs. For PbS QDs-sensitized solar cell, the obtained value of η = 1.1%, J sc = 20.60 mA/cm2, V oc = 155 mV, and FF = 34.7%, respectively. The photovoltaic performance of the device in this study is still inferior. However, it is the first report regarding to ZnO/ZnZe NWs/PbS QDs solar cell. The achieving high absorption and large short circuit current density may interest in further improvement of the device performance by suppressing surface defects, optimizing the quality of ZnO/ZnSe NWs and PbS QDs.

  10. The accumulation of elements in plants growing spontaneously on small heaps left by the historical Zn-Pb ore mining.

    Science.gov (United States)

    Stefanowicz, Anna M; Stanek, Małgorzata; Woch, Marcin W; Kapusta, Paweł

    2016-04-01

    The study evaluated the levels of nine metals, namely Ca, Cd, Fe, K, Mg, Mn, Pb, Tl, and Zn, in soils and tissues of ten plant species growing spontaneously on heaps left by historical mining for Zn-Pb ores. The concentrations of Cd, Pb, Tl, and Zn in heap soils were much higher than in control soils. Plants growing on heaps accumulated excessive amounts of these elements in tissues, on average 1.3-52 mg Cd kg(-1), 9.4-254 mg Pb kg(-1), 0.06-23 mg Tl kg(-1) and 134-1479 mg Zn kg(-1) in comparison to 0.5-1.1 mg Cd kg(-1), 2.1-11 mg Pb kg(-1), 0.02-0.06 mg Tl kg(-1), and 23-124 mg Zn kg(-1) in control plants. The highest concentrations of Cd, Pb, and Zn were found in the roots of Euphorbia cyparissias, Fragaria vesca, and Potentilla arenaria, and Tl in Plantago lanceolata. Many species growing on heaps were enriched in K and Mg, and depleted in Ca, Fe, and Mn. The concentrations of all elements in plant tissues were dependent on species, organ (root vs. shoot), and species-organ interactions. Average concentrations of Ca, K, and Mg were generally higher in shoots than in roots or similar in the two organs, whereas Cd, Fe, Pb, Tl, and Zn were accumulated predominantly in the roots. Our results imply that heaps left by historical mining for Zn-Pb ores may pose a potential threat to the environment and human health.

  11. Effect of temperature, gas phase composition, pH and microbial activity on As, Zn, Pb and Cd mobility in selected soils in the Ebro and Meuse Basins in the context of global change

    Energy Technology Data Exchange (ETDEWEB)

    Joubert, A.V.P. [Laboratoire des Interactions Micro-organismes, Mineraux et Matieres organiques dans les Sols (LIMOS) UMR 7137, Nancy University, CNRS, BP 239, 54506 Vandoeuvre-les-Nancy cedex (France)]. E-mail: antoine.joubert@limos.uhp-nancy.fr; Lucas, L. [Bureau de Recherches Geologiques et Minieres (BRGM), Service Environnement et Procedes Innovants-Unite Ecotechnologie (EPI/ECO), 3 Avenue Claude Guillemin, BP 6009, 45060 Orleans cedex 2 (France); Garrido, F. [Bureau de Recherches Geologiques et Minieres (BRGM), Service Environnement et Procedes Innovants-Unite Ecotechnologie (EPI/ECO), 3 Avenue Claude Guillemin, BP 6009, 45060 Orleans cedex 2 (France)]. E-mail: f.garrido@brgm.fr; Joulian, C. [Bureau de Recherches Geologiques et Minieres (BRGM), Service Environnement et Procedes Innovants-Unite Ecotechnologie (EPI/ECO), 3 Avenue Claude Guillemin, BP 6009, 45060 Orleans cedex 2 (France); Jauzein, M. [Laboratoire des Interactions Micro-organismes, Mineraux et Matieres organiques dans les Sols (LIMOS) UMR 7137, Nancy University, CNRS, BP 239, 54506 Vandoeuvre-les-Nancy cedex (France)

    2007-08-15

    This study estimates the effect of environmental parameters on the mobility of four inorganic contaminants (As, Zn, Pb and Cd) in soils from three areas in the Ebro and Meuse River basins, within the context of global change. An experimental method, applicable to various soil systems, is used to measure the effect of four global-change-sensitive parameters (temperature, gas phase composition, pH and microbial activity). The aqueous phase of batch incubations was sampled regularly to monitor toxic element concentrations in water. Statistical processing enabled discrimination of the most relevant variations in dissolved concentrations measured at different incubation times and under different experimental conditions. Gas phase composition was identified as the most sensitive parameter for toxic element solubilization. This study confirms that total soil concentrations of inorganic pollutants are irrelevant when assessing the hazard for ecosystems or water resource quality. - An experimental method applicable for different soil systems enables the determination of the effect of environmental parameters, potentially affected by global change, on the mobilization of inorganic pollutants.

  12. EPR and FTIR spectroscopic studies of MO-Al2O3-Bi2O3-B2O3-MnO2(M = Pb, Zn and Cd) glasses

    Science.gov (United States)

    Lalitha Phani, A. V.; Sekhar, K. Chandra; Chakradhar, R. P. S.; Narasimha Chary, M.; Shareefuddin, Md

    2018-03-01

    Glasses of the system (30-x)MO-xAl2O3-15Bi2O3-54.5B2O3-0.5MnO2 [M = Pb, Zn & Cd] (x = 0, 5, 10 & 15 mol%) were prepared by the normal melt quenching method. The amorphous nature of the prepared glasses was confirmed by the XRD studies. The EPR and FTIR studies were carried out at room temperature (RT). The EPR spectra exhibited three resonance signals at g ≈ 2.0 with a hyperfine structure, an absorption around g = 4.3 and a distinct shoulder at g = 3.3. Deconvoluted spectra were drawn for g ≈ 2.0 to resolve the six hyperfine lines. The electron paramagnetic resonance signal at g ≈ 2.0 indicates that the Mn2+ ions are in nearly perfectly octahedral symmetry. The low field signals at g = 3.3 and g = 4.3 are attributed to the Mn2+ ion which are in distorted rhombic symmetries. The hyperfine (HF) splitting constant (A) values suggested that the bonding between Mn2+ ions and its ligands is ionic in nature. The presence of BO3 and BO4 borate units, metal oxide cation units, Mn2+ and Bi-O bond vibrations in BiO3 units were noticed from the FTIR spectra.

  13. Preparation and Spectral Properties of Mixed-Ligand Complexes of VO(IV, Ni(II, Zn(II, Pd(II, Cd(II and Pb(II with Dimethylglyoxime and N-acetylglycine

    Directory of Open Access Journals (Sweden)

    Shayma A. Shaker

    2010-01-01

    Full Text Available A number of mixed-ligand complexes of the general formula [M(D(G] where D=dimethylglyoximato monoanion, G=N-acetylglycinato and M=VO(IV, Ni(II, Zn(II, Pd(II, Cd(II and Pb(II were prepared. Each complex was characterized by elemental analysis, determination of metal, infrared spectra, electronic spectra, (1H and 13C NMR spectra, conductivity and magnetic moments. All these complexes were not soluble in some of the organic solvent but highly soluble in dimethylformamide. The conductivity data showed the non-electrolytic nature of the complexes. The electronic spectra exhibited absorption bands in the visible region caused by the d-d electronic transition such as VO(IV, Ni(II and Pd(II. The IR and (1H, 13C NMR spectra which have indicate that the dimethylglyoxime was coordinated with the metal ions through the N and O atoms of the oxime group and N-acetylglycine was coordinated with metal ions through the N atom and terminal carboxyl oxygen atom.

  14. Pre-treatment processes of Azolla filiculoides to remove Pb(II), Cd(II), Ni(II) and Zn(II) from aqueous solution in the batch and fixed-bed reactors.

    Science.gov (United States)

    Khosravi, Morteza; Rakhshaee, Roohan; Ganji, Masuod Taghi

    2005-12-09

    Intact and treated biomass can remove heavy metals from water and wastewater. This study examined the ability of the activated, semi-intact and inactivated Azolla filiculoides (a small water fern) to remove Pb(2+), Cd(2+), Ni(2+) and Zn(2+) from the aqueous solution. The maximum uptake capacities of these metal ions using the activated Azolla filiculoides by NaOH at pH 10.5 +/- 0.2 and then CaCl(2)/MgCl(2)/NaCl with total concentration of 2 M (2:1:1 mole ratio) in the separate batch reactors were obtained about 271, 111, 71 and 60 mg/g (dry Azolla), respectively. The obtained capacities of maximum adsorption for these kinds of the pre-treated Azolla in the fixed-bed reactors (N(o)) were also very close to the values obtained for the batch reactors (Q(max)). On the other hand, it was shown that HCl, CH(3)OH, C(2)H(5)OH, FeCl(2), SrCl(2), BaCl(2) and AlCl(3) in the pre-treatment processes decreased the ability of Azolla to remove the heavy metals in comparison to the semi-intact Azolla, considerably. The kinetic studies showed that the heavy metals uptake by the activated Azolla was done more rapid than those for the semi-intact Azolla.

  15. Synthesis and characterization of sulfur functionalized graphene oxide nanosheets as efficient sorbent for removal of Pb2+, Cd2+, Ni2+ and Zn2+ ions from aqueous solution: A combined thermodynamic and kinetic studies

    Science.gov (United States)

    Pirveysian, Mahtab; Ghiaci, Mehran

    2018-01-01

    A very simple, one pot method was used for preparation of sulfur functionalized graphene oxide (GO-SOxR) with sodium sulfide and water in reflux condition. The elemental analysis data showed high sulfur content up to 15%. EDS and XPS analysis also proved introduction of sulfur element. To make the sorbent more efficient operationally, the GO-SOxR was coated with a mesoporous shell of TiO2 or SiO2. The prepared sorbents were characterized by SEM, TEM, TGA, XPS, XRD, IR and EDS. GO-SOxR@TiO2 and GO-SOxR@SiO2 composites were tested for removal of Pb(II), Cd(II), Ni(II) and Zn(II) as heavy metal ions from aqueous solution in batch method. Adsorption of the heavy metal ions was studied kinetically, and the adsorption capacities of GO-SOxR, GO-SOxR@TiO2, and GO-SOxR@SiO2 were evaluated using equilibrium adsorption isotherms, and compared to other adsorbents used for removal of these heavy metals. Kinetic studies showed that the experimental data was fitted with pseudo second order model. The adsorption capacity of GO was significantly improved by sulfur functionalization and TiO2 coating.

  16. Solvent extraction of Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Mn2+, Co2+ and Ni2+ into nitrobenzene using strontium dicarbol-lylcobaltate and tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate

    Directory of Open Access Journals (Sweden)

    E. MAKRLÍK

    2008-12-01

    Full Text Available The exchange extraction constants corresponding to the general equilibrium M2+(aq + SrL2+(nb D ML2+ (nb + Sr2+ (aq occurring in the two-phase water–nitrobenzene system (M2+ = Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Mn2+, Co2+ or Ni2+; L = tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate; aq = aqueous phase; nb = nitrobenzene phase were evaluated from extraction experiments and -activity measurements. Furthermore, the stability constants of the ML2+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order Ba2+ < Mn2+ < Pb2+, Co2+ < Cu2+, Zn2+ < Cd2+, Ni2+ < UO22+ < Ca2+.

  17. The matrix effect study in the spectrographic analysis of rare earth elements. Pt. 1. The influence of Sn, Pb, Sb, Bi, Cu, Ag, Zn and Cd on the spectral lines intensity of Y, La, Ce, Pr, Nd and Sm in the current arc exciting between C-electrodes

    International Nuclear Information System (INIS)

    Wysocka-Lisek, J.; Paszkowska, B.; Mularczyk, K.

    1976-01-01

    In the beginning the influence of Sn, Pb, Sb, Bi, Cu, Ag, Zn and Cd on the light rare earth spectral lines using Ni as the internal standard, during the intermittent current arc excitation between C-electrodes was studied. On the basis of the spectral lines intensity measurements, it was stated that one may apply the addition of Ni as the internal standard by the quantitative determination of Sn, Pb, Sb, Bi, Zn and Cd in the light rare earth mixtures with one of the above. Also a great influence of the presence of the individually studied metal was observed on the spectral line intensity of rare earth elements and nickel. The differences of the thermo-chemical reactions nature between excited elements and the carbon of the electrodes may cause that influence. (author)

  18. Accumulation of Pb, Cd and Zn from contaminated soil to various plants and evaluation of soil remediation with indicator plant (Plantago lanceolata L.)

    Energy Technology Data Exchange (ETDEWEB)

    Zupan, M.; Lobnik, F.; Kadunc, V. [Ljubljana Univ. (Slovenia). Agronomy Dept., Center for Soil and Environmental Science; Hudnik, V. [National Institute of Chemistry Hajdrihova 19, Ljubljana (Slovenia)

    1997-12-31

    The accumulation of cadmium, lead, and zinc by different major cultivated plants from soils contaminated with heavy metals, is presented. The vegetables, crops, and the indicator plant narrow leaf plantain (Plantago lanceolata L.) were used in a field experiment including 3 areas with different levels of pollution. The highest concentrations of heavy metals were observed in edible green parts of vegetables (endive, spinach, lettuce) and roots (carrot, red beet, radish). The heavy metal content in leguminous plants (pods and seeds) was very low compared to high soil concentrations. Wheat and maize showed lower concentrations in grains and kernels than in green parts. Lime and vermiculite were used for reduction of Cd availability to plants in polluted soil. The Cd concentration decreased in the narrow leaf plantain in the presence of both lime and vermiculite in acid soil. In the higher-pH soil the Cd availability to spinach was greatly reduced in the presence of vermiculite

  19. 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.

  20. Heavy metal / polyacid interaction : an electrochemical study of the binding of Cd(II), Pb(II) and Zn(II) to polycarboxylic and humic acids

    NARCIS (Netherlands)

    Cleven, R.F.M.J.

    1984-01-01

    Polyelectrolyte effects in the interaction of heavy metal ions with model polycarboxylic acids have been described, in order to establish the relevance of these effects in the interaction of heavy metal ions with naturally occurring humic and fulvic acids. The model systems consisted of Cd(II),

  1. 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

    allows identifying a range of behavioral model parameter sets. The small catchment size and nearness of the rain gauge justified excluding the hydrological model parameters from the uncertainty assessment. Uniform, closed prior distributions were heuristically specified for the dry and wet removal...... of accumulated metal available on the conceptual catchment surface. Forward Monte Carlo analysis based on the posterior parameter sets covered 95% of the observed event mean concentrations, and 95% prediction quantiles for site mean concentrations were estimated to 470 μg/l ±20% for Zn, 295 μg/l ±40% for Cu, 20...

  2. Heavy metals (Cd, Cu, Ni and Pb) content in two fish species of ...

    African Journals Online (AJOL)

    GREGORY

    2010-09-13

    Sep 13, 2010 ... Water pollution and fish physiology. CRC press. Florida, USA, p. 245. Kalay M, Canli M (2000). Elimination of essential (Cu, Zn) and nonessential (Cd, Pb) metals from tissue of a freshwater fish Tilapia zillii following and uptake protocol. Turk. J. Zool. 24: 429-436. Karadede H, Ünlü E (2000). Concentrations ...

  3. Concentrations, spatial distribution, and risk assessment of soil heavy metals in a Zn-Pb mine district in southern China.

    Science.gov (United States)

    Qi, Jianying; Zhang, Hailong; Li, Xiangping; Lu, Jian; Zhang, Gaosheng

    2016-07-01

    China is one of the largest producers and consumers of lead and zinc in the world. Lead and zinc mining and smelting can release hazardous heavy metals such as Cd, Pb, Zn, and As into soils, exerting health risks to human by chronic exposure. The concentrations of Cd, Zn, Pb, and As in soil samples collected from a Pb-Zn mining area with exploitation history of 60 years were investigated. Health risks of the heavy metals in soil were evaluated using US Environmental Protection Agency (US EPA) recommended method. A geo-statistical technique (Kriging) was used for the interpolation of heavy metals pollution and Hazard Index (HI). The results indicated that the long-term Pb/Zn mining activities caused the serious pollution in the local soil. The concentrations of Cd, As, Pb, and Zn in topsoil were 40.3 ± 6.3, 103.7 ± 37.3, 3518.4 ± 896.1, and 10,413 ± 2973.2 mg/kg dry weight, respectively. The spatial distribution of the four metals possessed similar patterns, with higher concentrations around Aayiken (AYK), Maseka (MSK), and Kuangshan (KS) area and more rapidly dropped concentrations at upwind direction than those at downwind direction. The main pollutions of Cd and Zn were found in the upper 60 cm, the Pb was found in the upper 40 cm, and the As was in the upper 20 cm. The mobility of metals in soil profile of study area was classed as Cd > Zn ≫ Pb > As. Results indicated that there was a higher health risk (child higher than adult) in the study area. Pb contributed to the highest Hazard Quotient (57.0 ~ 73.9 %) for the Hazard Index.

  4. 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.

  5. Adsorpsi Pb2+ dan Zn2+ pada Biomassa Imperata cylindrica

    Directory of Open Access Journals (Sweden)

    Noer Komari

    2017-03-01

    Full Text Available Metode alternatif untuk mengatasi pencemaran logam berat adalah biosorpsi menggunakan biomassa sebagai adsorben. Telah dilakukan penelitian kajian adsorpsi campuran Pb2+ dan Zn2+ pada biomassa Imperata cylindrica sebagai adsorben. Tujuan penelitian adalah mengetahui kemampuan biomassa mengadsorpsi Pb2+ dan Zn2+. Preparasi biomassa dilakukan dengan aktivasi menggunakan asam nitrat dan amonium hidroksida. Adsorpsi dilakukan dengan sistem batch. Parameter yang diukur adalah pH optimum, waktu kontak optimum, kapasitas adsorpsi dan recovery ion logam. Analisis kadar logam dilakukan dengan menggunakan Spektrofotometer Serapan Atom (AAS. Hasil penelitian menunjukkan pH optimum adsorpsi Pb2+ dan Zn2+ masing-masing pada pH 5 dan pH 6. Waktu kontak optimum adsorpsi Pb2+ dan Zn2+ masing masing pada 40 menit dan 30 pertama. Kapasitas adsorpsi Pb2+ dan Zn2+ pada konsentrasi awal 10 ppm masing-masing adalah 90,95% dan 43,60%. Recovery Pb2+ dan Zn2+ masing-masing 84,45% dan 57,13%.

  6. 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.

  7. Synthesis and characterization of ZnO/ZnSe NWs/PbS QDs solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Kamruzzaman, M, E-mail: kzaman.phy11@gmail.com; Zapien, J A, E-mail: apjazs@cityu.edu.hk [City University of Hong Kong, Department of Physics and Materials Science and Center Of Super-Diamond and Advanced Films (COSDAF) (China)

    2017-04-15

    The capture of solar energy has gained the attention for the next generation solar cell. ZnO/ZnSe NW arrays were synthesized on an FTO glass substrate using a simple and facile hydrothermal and ion-exchange approaches. The lead sulfide (PbS) QDs was infiltrated into ZnO/ZnSe NWs via SILAR method for making inorganic quantum dot sensitized ZnO/ZnSe/PbS QDs solar cell. The surface morphology, structural, optical, and J-V characteristics have been investigated. The ZnO/ZnSe NW is a core–shell like structure, and the absorption edge shifted from the UV region (ZnO NWs) to the near infrared region for ZnO/ZnSe NWs/PbS QDs. For PbS QDs-sensitized solar cell, the obtained value of η = 1.1%, J{sub sc} = 20.60 mA/cm{sup 2}, V{sub oc} = 155 mV, and FF = 34.7%, respectively. The photovoltaic performance of the device in this study is still inferior. However, it is the first report regarding to ZnO/ZnZe NWs/PbS QDs solar cell. The achieving high absorption and large short circuit current density may interest in further improvement of the device performance by suppressing surface defects, optimizing the quality of ZnO/ZnSe NWs and PbS QDs.

  8. Influence of hydrology on heavy metal speciation and mobility in a Pb-Zn mine tailing

    International Nuclear Information System (INIS)

    Kovacs, Elza; Dubbin, William E.; Tamas, Janos

    2006-01-01

    Among the inorganic toxicants of greatest concern in mine tailings, Pb, Zn, Cu, Cd and As figure prominently due to their abundance and potential toxicity. Here we report on their biolability and solid-phase speciation in two sediment cores subject to variable hydrological regimes at an abandoned pyritic mine tailing. The oxic conditions of well-drained sediments induced pyrite oxidation and the subsequent liberation of H + , SO 4 2- and considerable quantities of Fe(III), which precipitated as goethite. Solubility of Pb, Zn, Cu and Cd was closely coupled to pH and goethite presence. Metal lability was particularly low in zones of neutralization, formed by the accumulation of calcite, first carried then deposited by percolating waters in both saturated and unsaturated cores. We conclude that differential hydrology induces variable heavy metal speciation and biolability in Pb-Zn mine tailings, and suggest that site-specific risk assessments must account for past and present hydrological regimes. - Variable hydrology influences heavy metal speciation and mobility, and the formation of neutralization zones, in a Pb-Zn mine tailing

  9. Soil heavy metal pollution and risk assessment associated with the Zn-Pb mining region in Yunnan, Southwest China.

    Science.gov (United States)

    Cheng, Xianfeng; Danek, Tomas; Drozdova, Jarmila; Huang, Qianrui; Qi, Wufu; Zou, Liling; Yang, Shuran; Zhao, Xinliang; Xiang, Yungang

    2018-03-07

    The environmental assessment and identification of sources of heavy metals in Zn-Pb ore deposits are important steps for the effective prevention of subsequent contamination and for the development of corrective measures. The concentrations of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in soils from 40 sampling points around the Jinding Zn-Pb mine in Yunnan, China, were analyzed. An environmental quality assessment of the obtained data was performed using five different contamination and pollution indexes. Statistical analyses were performed to identify the relations among the heavy metals and the pH in soils and possible sources of pollution. The concentrations of As, Cd, Pb, and Zn were extremely high, and 23, 95, 25, and 35% of the samples, respectively, exceeded the heavy metal limits set in the Chinese Environmental Quality Standard for Soils (GB15618-1995, grade III). According to the contamination and pollution indexes, environmental risks in the area are high or extremely high. The highest risk is represented by Cd contamination, the median concentration of which exceeds the GB15618-1995 limit. Based on the combination of statistical analyses and geostatistical mapping, we identified three groups of heavy metals that originate from different sources. The main sources of As, Cd, Pb, Zn, and Cu are mining activities, airborne particulates from smelters, and the weathering of tailings. The main sources of Hg are dust fallout and gaseous emissions from smelters and tailing dams. Cr and Ni originate from lithogenic sources.

  10. Should legislation regarding maximum Pb and Cd levels in human food also cover large game meat?

    Science.gov (United States)

    Taggart, Mark A; Reglero, Manuel M; Camarero, Pablo R; Mateo, Rafael

    2011-01-01

    Game meat may be contaminated with metals and metalloids if animals reside in anthropogenically polluted areas, or if ammunition used to kill the game contaminates the meat. Muscle tissue from red deer and wild boar shot in Ciudad Real province (Spain) in 2005-06 was analysed for As, Pb, Cu, Zn, Se and Cd. Samples were collected from hunting estates within and outside an area that has been historically used for mining, smelting and refining various metals and metalloids. Meat destined for human consumption, contained more Pb, As and Se (red deer) and Pb (boar) when harvested from animals that had resided in mined areas. Age related accumulation of Cd, Zn and As (in deer) and Cd, Cu and Se (in boar) was also observed. Two boar meat samples contained high Pb, at 352 and 2408 μg/g d.w., and these were likely to have been contaminated by Pb ammunition. Likewise, 19-84% of all samples (depending on species and sampling area) had Pb levels > 0.1 μg/g w.w., the EU maximum residue level (MRL) for farm reared meat. Between 9 and 43% of samples exceeded comparable Cd limits. Such data highlight a discrepancy between what is considered safe for human consumption in popular farmed meat (chicken, beef, lamb), and what in game may often exist. A risk assessment is presented which describes the number of meals required to exceed current tolerable weekly intakes (PTWIs) for Pb and Cd, and the potential contribution of large game consumption to such intake limit criteria. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. Photoluminescence study of ZnS and ZnS:Pb nanoparticles

    International Nuclear Information System (INIS)

    Virpal,; Hastir, Anita; Kaur, Jasmeet; Singh, Gurpreet; Singh, Ravi Chand

    2015-01-01

    Photoluminescence (PL) study of pure and 5wt. % lead doped ZnS prepared by co-precipitation method was conducted at room temperature. The prepared nanoparticles were characterized by X-ray Diffraction (XRD), UV-Visible (UV-Vis) spectrophotometer, Photoluminescence (PL) and Raman spectroscopy. XRD patterns confirm cubic structure of ZnS and PbS in doped sample. The band gap energy value increased in case of Pb doped ZnS nanoparticles. The PL spectrum of pure ZnS was de-convoluted into two peaks centered at 399nm and 441nm which were attributed to defect states of ZnS. In doped sample, a shoulder peak at 389nm and a broad peak centered at 505nm were observed. This broad green emission peak originated due to Pb activated ZnS states

  12. 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.

  13. Kinetic modeling and thermodynamic study to remove Pb(II), Cd(II), Ni(II) and Zn(II) from aqueous solution using dead and living Azolla filiculoides

    Energy Technology Data Exchange (ETDEWEB)

    Rakhshaee, Roohan [Department of Applied Chemistry, Faculty of Chemistry, Islamic Azad University, Rasht Branch, P.O. Box 41335-3516, Rasht (Iran, Islamic Republic of); Khosravi, Morteza [Department of Applied Chemistry, Faculty of Chemistry, Islamic Azad University, North Tehran Branch, P.O. Box 191367-4711, Tehran 191367-4711 (Iran, Islamic Republic of)]. E-mail: drm_khosravi@yahoo.com; Ganji, Masoud Taghi [Department of Applied Chemistry, Faculty of Chemistry, Islamic Azad University, North Tehran Branch, P.O. Box 191367-4711, Tehran 191367-4711 (Iran, Islamic Republic of)

    2006-06-30

    Dead Azolla filiculoides can remove Pb{sup 2+},Cd{sup 2+}, Ni{sup 2+} and Zn{sup 2+} corresponding to second-order kinetic model. The maximum adsorption capacity (Q {sub max}) to remove these metal ions by the alkali and CaCl{sub 2}/MgCl{sub 2}/NaCl (2:1:1, molar ratio) activated Azolla from 283 to 313 K was 1.431-1.272, 1.173-0.990, 1.365-1.198 and 1.291-0.981 mmol/g dry biomass, respectively. Q {sub max} to remove these heavy metals by the non-activated Azolla at the mentioned temperature range was obtained 1.131-0.977, 1.092-0.921, 1.212-0.931 and 1.103-0.923 mmol/g dry biomass, respectively. In order to remove these metal ions by the activated Azolla, the enthalpy change ({delta}H) was -4.403, -4.495, -4.557 and -4.365 kcal/mol and the entropy change ({delta}S) was 2.290, 1.268, 1.745 and 1.006 cal/mol K, respectively. While, to remove these metal ions by the non-activated Azolla, {delta}H was -3.685, -3.766, -3.967 and -3.731 kcal/mol and {delta}S was 2.440, 1.265, 1.036 and 0.933 cal/mol K, respectively. On the other hand, the living Azolla removed these heavy metals corresponding to first-order kinetic model. It was also shown that pH, temperature and photoperiod were effective both on the rate of Azolla growth and the rate of heavy metals uptake during 10 days. It was appeared the use of Ca(NO{sub 3}){sub 2} increased both Azolla growth rate and the rate of heavy metals uptake while the using KNO{sub 3} although increased Azolla growth rate but decreased the rate of heavy metals uptake.

  14. Kinetic modeling and thermodynamic study to remove Pb(II), Cd(II), Ni(II) and Zn(II) from aqueous solution using dead and living Azolla filiculoides.

    Science.gov (United States)

    Rakhshaee, Roohan; Khosravi, Morteza; Ganji, Masoud Taghi

    2006-06-30

    Dead Azolla filiculoides can remove Pb(2+),Cd(2+), Ni(2+) and Zn(2+) corresponding to second-order kinetic model. The maximum adsorption capacity (Q(max)) to remove these metal ions by the alkali and CaCl(2)/MgCl(2)/NaCl (2:1:1, molar ratio) activated Azolla from 283 to 313K was 1.431-1.272, 1.173-0.990, 1.365-1.198 and 1.291-0.981mmol/g dry biomass, respectively. Q(max) to remove these heavy metals by the non-activated Azolla at the mentioned temperature range was obtained 1.131-0.977, 1.092-0.921, 1.212-0.931 and 1.103-0.923mmol/g dry biomass, respectively. In order to remove these metal ions by the activated Azolla, the enthalpy change (DeltaH) was -4.403, -4.495, -4.557 and -4.365kcal/mol and the entropy change (DeltaS) was 2.290, 1.268, 1.745 and 1.006cal/molK, respectively. While, to remove these metal ions by the non-activated Azolla, DeltaH was -3.685, -3.766, -3.967 and -3.731kcal/mol and DeltaS was 2.440, 1.265, 1.036 and 0.933cal/molK, respectively. On the other hand, the living Azolla removed these heavy metals corresponding to first-order kinetic model. It was also shown that pH, temperature and photoperiod were effective both on the rate of Azolla growth and the rate of heavy metals uptake during 10 days. It was appeared the use of Ca(NO(3))(2) increased both Azolla growth rate and the rate of heavy metals uptake while the using KNO(3) although increased Azolla growth rate but decreased the rate of heavy metals uptake.

  15. The Enrichment and Transfer of Heavy Metals for Two Ferns in Pb-Zn Tailing

    Directory of Open Access Journals (Sweden)

    Mai Jiajie

    2017-01-01

    Full Text Available The enrichment and transfer of 8 heavy metals of Equisetum ramosissimum and Pteris vittata growing naturally close to edge of the sewage pool in Bencun Pb-Zn Tailing, Eastern Guangdong were investigated. The results indicated that the pollution of Cd, Pb, Hg, Zn was very severe in this tailing, followed by Cu and Mn. The potential ecological risk of heavy metals was assessed to be very strong based on soil background values of Guangdong Province and at high risk according to criteria of the second grade State Soil Environmental Quality Standard, and Cd, Hg, Pb were the main factors leading to potential ecological risk. The content of 8 heavy metals in the two ferns did not reach critical content of hyperaccumulator, so neither of them was typical hyperaccumulator, but both had a certain tolerance to these heavy metal pollution. Underground parts of Pteris vittata had an enrichment coefficient above 1 and that of Equisetum ramosissimum had a value near 1, therefore the two ferns could be utilized as potential enrichment plants. The two ferns have strong adaptability to the tailing habitat and can be used as pioneers in ecological restoration of Pb-Zn tailings.

  16. 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.

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

    Directory of Open Access Journals (Sweden)

    Longbin Huang

    Full Text Available 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(CO32 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,FeS, ZnS, (Zn,CdS 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.

  18. Spatial distribution and risk assessment of heavy metals in soil near a Pb/Zn smelter in Feng County, China.

    Science.gov (United States)

    Shen, Feng; Liao, Renmei; Ali, Amjad; Mahar, Amanullah; Guo, Di; Li, Ronghua; Xining, Sun; Awasthi, Mukesh Kumar; Wang, Quan; Zhang, Zengqiang

    2017-05-01

    A large scale survey and a small scale continuous monitoring was conducted to evaluate the impact of Pb/Zn smelting on soil heavy metals (HMs) accumulation and potential ecological risk in Feng County, Shaanxi province of China. Soil parameters including pH, texture, CEC, spatial and temporal distribution of HMs (Cd, Cu, Ni, Pb and Zn), and BCR fractionation were monitored accordingly. The results showed the topsoil in the proximity of smelter, especially the smelter area and county seat, were highly polluted by HMs in contrast to the river basins. Fractionation of Cd and Zn in soil samples revealed higher proportion of mobile fractions than other HMs. The soil Cd and Zn contents decreased vertically, but still exceeded the second level limits of Environmental Quality Standard for Soils of China (EQSS) within 80cm. The dominated soil pollutant (Cd) had higher ecological risk than Cu, Ni, Zn and Pb. The potential ecological risk (PER) factor of Cd were 65.7% and 100% in surrounding county and smelter area, respectively. The long-term smelter dust emission mainly contributed to the HMs pollution and posed serious environment risk to living beings. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Pixelated CdZnTe drift detectors

    DEFF Research Database (Denmark)

    Kuvvetli, Irfan; Budtz-Jørgensen, Carl

    2005-01-01

    A technique, the so-called Drift Strip Method (DSM), for improving the CdZnTe detector energy response to hard X-rays and gamma-rays was applied as a pixel geometry. First tests have confirmed that this detector type provides excellent energy resolution and imaging performance. We specifically...... report on the performance of 3 mm thick prototype CZT drift pixel detectors fabricated using material from eV-products. We discuss issues associated with detector module performance. Characterization results obtained from several prototype drift pixel detectors are presented. Results of position...

  20. Stable and metastable phases in reciprocal systems PbSe + Ag2I2 Ag2Se + PbI2 and PbSe + CdI2 = CdSe + PbI2

    International Nuclear Information System (INIS)

    Odin, I.N.; Grin'ko, V.V.; Kozlovskij, V.F.; Safronov, E.V.

    2005-01-01

    Mutual system PbSe + Ag 2 I 2 = Ag 2 Se + PbI 2 is investigated. It is shown that diagonal Ag 2 Se-PbI 2 is stable. Liquidus surface and isothermal section at 633 K of phase diagram of PbSe-Ag 2 Se-PbI 2 system are built. Transformations directing to crystallization metastable ternary compound forming in PbSe-PbI 2 system and metastable polytype modifications of lead iodide in PbSe-Ag 2 Se-PbI 2 system at 620-685 K are studied. By hardening from molten state (1150-1220 K) new interstitial metastable phases crystallizing in CdCl 2 structural type are obtained in PbSe-Ag 2 Se-PbI 2 and PbSe + CdI 2 = CdSe + PbI 2 systems [ru

  1. Effects of Diatomite Organic Fertilizer on Cd and Zn Forms and Availability of Cd-Zn Polluted Soil

    OpenAIRE

    LIN Ji; CHENG Chen; HAN Ming-qiang; LI Song-xing; MA Xiao-rui; LI Yan

    2014-01-01

    An indoor soil cultivation experiment was carried out to study the effects of diatomite organic fertilizer on the forms and the avail-ability of Cd, Zn in soil. The results showed that the soil pH increased, the soil available Cd and Zn reduced after diatomite organic fertilizer application in contaminated soil. Diatomite organic fertilizer application decreased the contents of exchangeable form and weakly-bound-to organic form of Cd and Zn significantly, but increased the contents of strongl...

  2. Relationships between T-cell-mediated immune response and Pb, Zn, Cu, Cd, and as concentrations in blood of nestling white storks (Ciconia ciconia) and black kites (Milvus migrans) from Doñana (southwestern Spain) after the Aznalcóllar toxic spill.

    Science.gov (United States)

    Baos, Raquel; Jovani, Roger; Forero, Manuela G; Tella, José L; Gómez, Gemma; Jiménez, Begoña; González, María J; Hiraldo, Fernando

    2006-04-01

    In the Aznalcóllar mining accident (April 1998), nearly six million cubic meters of toxic wastes were spilled in the surroundings of the Doñana National Park (southwestern Spain). The present study focused on the likely effects of metal pollution on the immune system of nestling white storks (Ciconia ciconia) and black kites (Milvus migrans) sampled in the nearby area. Using the phytohaemagglutinin skin test, we examined cell-mediated immune response (CMI) in relation to Pb, Zn, Cu, Cd, and As concentrations in blood of 281 nestling white storks and of 89 black kites. The former species was monitored along a four-year period (1999, 2001-2003), while black kites were sampled in 1999. Overall, average levels of heavy metals and As were relatively low when compared to those reported for birds in metal-polluted areas. Copper showed a negative effect on CMI in both species, although the relationship was significant only for white storks in 2002. We found no evidence that environmental exposure to Pb, Zn, As, and Cd had any effect on nestlings' CMI. Interannual consistency is revealed as an important factor, supporting the need of long-term studies when assessing the immunotoxic effects of metal exposure in the wild.

  3. Noise in CdZnTe detectors

    International Nuclear Information System (INIS)

    Luke, P. N.; Amman, M.; Lee, J. S.; Manfredi, P. F.

    2000-01-01

    Noise in CdZnTe devices with different electrode configurations was investigated. Measurements on devices with guard-ring electrode structures showed that surface leakage current does not produce any significant noise. The parallel white noise component of the devices appeared to be generated by the bulk current alone, even though the surface current was substantially higher. This implies that reducing the surface leakage current of a CdZnTe detector may not necessarily result in a significant improvement in noise performance. The noise generated by the bulk current is also observed to be below full shot noise. This partial suppression of shot noise may be the result of Coulomb interaction between carriers or carrier trapping. Devices with coplanar strip electrodes were observed to produce a 1/f noise term at the preamplifier output. Higher levels of this 1/f noise were observed with decreasing gap widths between electrodes. The level of this 1/f noise appeared to be independent of bias voltage and leakage current but was substantially reduced after certain surface treatments

  4. Effects of Diatomite Organic Fertilizer on Cd and Zn Forms and Availability of Cd-Zn Polluted Soil

    Directory of Open Access Journals (Sweden)

    LIN Ji

    2014-08-01

    Full Text Available An indoor soil cultivation experiment was carried out to study the effects of diatomite organic fertilizer on the forms and the avail-ability of Cd, Zn in soil. The results showed that the soil pH increased, the soil available Cd and Zn reduced after diatomite organic fertilizer application in contaminated soil. Diatomite organic fertilizer application decreased the contents of exchangeable form and weakly-bound-to organic form of Cd and Zn significantly, but increased the contents of strongly-bound-to organic form and residual form of Cd and Zn in con-taminated soil. Statistics analysis showed that the contents of exchangeable and weakly-bound-to organic form of Cd and Zn had highly sig-nificant relation to the content of soil available Cd and Zn(P<0.01. The contents of Mn oxide-occluded Cd had significant relation to the con-tent of soil available Cd(P<0.05. Comparing the treatments of diatomite organic fertilizer with the rate of 5%and 10%soil weight, there was no significant difference in soil pH, the contents of soil available Cd, Zn and the forms of Cd, Zn.

  5. Assessment of heavy metals (Cd and Pb) and micronutrients (Cu, Mn, and Zn) of paddy (Oryza sativa L.) field surface soil and water in a predominantly paddy-cultivated area at Puducherry (Pondicherry, India), and effects of the agricultural runoff on the elemental concentrations of a receiving rivulet.

    Science.gov (United States)

    Reddy, M Vikram; Satpathy, Deepmala; Dhiviya, K Shyamala

    2013-08-01

    The concentrations of toxic heavy metals-Cd and Pb and micronutrients-Cu, Mn, and Zn were assessed in the surface soil and water of three different stages of paddy (Oryza sativa L.) fields, the stage I-the first stage in the field soon after transplantation of the paddy seedlings, holding adequate amount of water on soil surface, stage II-the middle stage with paddy plants of stem of about 40 cm length, with sufficient amount of water on the soil surface, and stage III-the final stage with fully grown rice plants and very little amount of water in the field at Bahour, a predominantly paddy cultivating area in Puducherry located on the southeast Coast of India. Comparison of the heavy metal and micronutrient concentrations of the soil and water across the three stages of paddy field showed their concentrations were significantly higher in soil compared with that of water (p soil. The elemental concentrations in paddy soil as well as water was in the ranking order of Cd > Mn > Zn > Cu > Pb indicating concentration of Cd was maximum and Pb was minimum. The elemental concentrations in both soil and water across the three stages showed a ranking order of stage II > stage III > stage I. The runoff from the paddy fields has affected the elemental concentrations of the water and sediment of an adjacent receiving rivulet.

  6. Metal and metalloid contamination in roadside soil and wild rats around a Pb-Zn mine in Kabwe, Zambia

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Shouta M.M.; Ikenaka, Yoshinori; Hamada, Kyohei [Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818 (Japan); Muzandu, Kaampwe; Choongo, Kennedy [Department of Biomedical Studies, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka (Zambia); Teraoka, Hiroki; Mizuno, Naoharu [Department of Toxicology, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu 069-8501 (Japan); Ishizuka, Mayumi, E-mail: ishizum@vetmed.hokudai.ac.j [Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818 (Japan)

    2011-01-15

    Metal (Cr, Co, Cu, Zn, Cd, Pb, Ni) and metalloid (As) accumulation was studied in roadside soil and wild rat (Rattus sp.) samples from near a Pb-Zn mine (Kabwe, Zambia) and the capital city of Zambia (Lusaka). The concentrations of the seven metals and As in the soil samples and Pb in the rat tissue samples were quantified using atomic absorption spectroscopy. The concentrations of Pb, Zn, Cu, Cd, and As in Kabwe soil were much higher than benchmark values. Geographic Information System analysis indicated the source of metal pollution was mining and smelting activity. Interestingly, the area south of the mine was more highly contaminated even though the prevailing wind flow was westward. Wild rats from Kabwe had much higher tissue concentrations of Pb than those from Lusaka. Their body weight and renal Pb levels were negatively correlated, which suggests that mining activity might affect terrestrial animals in Kabwe. - The area around Kabwe, Zambia is highly polluted with metals and As. Wild rats from this area had high tissue concentrations of Pb and decreased body weight.

  7. Cd, Zn, Ni and Cu in the Indian Ocean

    NARCIS (Netherlands)

    Saager, Paul M.; Baar, Hein J.W. de; Howland, Robin J.

    1992-01-01

    Vertical profiles of dissolved Cd, Zn, Ni and Cu in the Northwest Indian Ocean (Arabian Sea) exhibit a nutrient type distribution also observed in other oceans. The area is characterized by strong seasonal upwelling and a broad oxygen minimum zone in intermediate waters. However, neither Cd, Zn, Ni

  8. Adsorption of Cu, As, Pb and Zn by Banana Trunk

    International Nuclear Information System (INIS)

    Nurzulaifa Shaheera Erne Mohd Yasim; Zitty Sarah Ismail; Suhanom Mohd Zaki; Mohd Fahmi Abd Azis

    2016-01-01

    The purpose of this study is to investigate the effectiveness of banana trunk as an adsorbent in removal of heavy metals in aqueous solution. Functional groups of adsorbent were determined using Fourier Transform Infrared spectroscopy (FTIR). Batch experiments were conducted to determine the adsorption percentage of heavy metals (Cu, As, Pb and Zn). The optimum adsorption using banana trunk was based on pH difference, contact time and dosage. Adsorption percentage was found to be proportional to pH, contact time and dosage. Maximum adsorption percentage of Cu, As, Pb and Zn at pH 6, 100 minutes and 8 gram of dosage are 95.80 %, 75.40 %, 99.36 % and 97.24 %, respectively. Langmuir and Freundlich isotherms were used to determine the equilibrium state for heavy metals ion adsorption experiments. All equilibrium heavy metals were well explained by the Freundlich isotherm model with R"2= 0.9441, R"2= 0.8671, R"2= 0.9489 and R"2= 0.9375 for Cu, As, Pb and Zn respectively. It is concluded that banana trunk has considerable potential for the removal of heavy metals from aqueous solution. (author)

  9. Surface tension modelling of liquid Cd-Sn-Zn alloys

    Science.gov (United States)

    Fima, Przemyslaw; Novakovic, Rada

    2018-06-01

    The thermodynamic model in conjunction with Butler equation and the geometric models were used for the surface tension calculation of Cd-Sn-Zn liquid alloys. Good agreement was found between the experimental data for limiting binaries and model calculations performed with Butler model. In the case of ternary alloys, the surface tension variation with Cd content is better reproduced in the case of alloys lying on vertical sections defined by high Sn to Zn molar fraction ratio. The calculated surface tension is in relatively good agreement with the available experimental data. In addition, the surface segregation of liquid ternary Cd-Sn-Zn and constituent binaries has also been calculated.

  10. Systems of Rb2I2-CdI2-PbI2 and Cs2I2-CdI2-PbI2

    International Nuclear Information System (INIS)

    Volchanskaya, V.V.; Il'yasov, I.I.

    1979-01-01

    The Rb 2 I 2 -CdI 2 -PbI 2 and Cs 2 I 2 -CdI 2 -PbI 2 triple systems have been studied, using the visual-polythermal method. The liquidus of the systems researched consists of the components and compounds crystallization fields: 2RbIxCdI 2 , 2RbIxRbI 2 , RbIxPbI 2 and 2CsIxCdI 2 , 4CsIxPbI 2 , CsIxPbI 2 , respectively. The crystallization fields converge in four non-variant points at 360, 280, 205 and 192 deg C in the Rb 2 I 2 -CdI 2 -PbI 2 system and at 375, 368, 208 and 190 deg C in the CsI 2 -CdI 2 -PbI 2 system

  11. EVALUATION OF CONTAMINATION OF Zn-Pb INDUSTRY DEGRADED AREAS USING SPATIAL INFORMATION

    Directory of Open Access Journals (Sweden)

    Rafał Rozpondek

    2017-06-01

    Full Text Available The aim of this study was to evaluate soil contamination by heavy metals of selected area in the vicinity of the Zinc Smelter „Miasteczko Śląskie” (surface area: 147 ha, 1050 x 1400 meters for purpose of future reclamation, remediation and monitoring. The study used GIS. Network of 29 measuring points was planned, with particular emphasis on the area with the least amount of pure vegetation. In March 2016, two samples of soil were taken from the top layer of soil 0 - 20cm. Samples were analyzed in terms of pH, soil organic matter and total heavy metal content (As, Ba, Cd, Cu, Ni, Pb i Zn. Values of pH maintained in range of 3,7 - 7,9, organic matter 0,8 – 47,1% of solid content, As 0 – 32,5mg/kg, Ba 14 – 804mg/kg, Cd 0 – 19mg/kg, Cu 3 – 58mg/kg, Pb 22 – 1893mg/kg, Zn 36 – 1377mg/kg. In collected samples Ni was not detected. Spatial distributions of results were created. A significant data range and spatial differentiation was noted. On the base of the Regulation of the Minister of the Environment from September 1st, 2016 on the method of conducting the assessment of contamination of surface of the earth, areas contaminated with heavy metals were selected. Two different concentration limits were adopted: first in accordance with the actual method of land use (permissible values for group III - woodland and second relating to the possible undertaking of measures targeted at changing the land use (limit values for Group I - residential areas, recreational areas. On the basis of generated models, the area of the surface size that contains values higher than allowed in the quoted regulation were determined and calculated. In case of group III the values were exceeded for: Zn (surface area 0,9ha, Pb (46ha i Cd (27,8ha. For group I: As (0,3ha, Ba (10,2ha, Cd (53,9ha, Pb (120,8ha i Zn (20,2ha. The concentrations of Ni and Cu were lower than the limit value. The paper also determined zones with the highest contents of heavy metals. In

  12. 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.

  13. Characterization of CdZnTe ambient temperature detectors

    International Nuclear Information System (INIS)

    Lavietes, A.

    1994-09-01

    A great deal of interest has been generated in the use of cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) detectors for ambient temperature detection of radionuclides. The addition of zinc to CdTe provides several benefits that enhance the materials operational characteristics at ambient temperature. Recent movement in the industry is to produce larger volume detectors using CdZnTe without much known about the effects of larger geometry on performance. The purpose of this study is to get an idea of the relationship of detector performance to both area and thickness variations

  14. Analysis of Etched CdZnTe Substrates

    Science.gov (United States)

    Benson, J. D.; Bubulac, L. O.; Jaime-Vasquez, M.; Lennon, C. M.; Arias, J. M.; Smith, P. J.; Jacobs, R. N.; Markunas, J. K.; Almeida, L. A.; Stoltz, A.; Wijewarnasuriya, P. S.; Peterson, J.; Reddy, M.; Jones, K.; Johnson, S. M.; Lofgreen, D. D.

    2016-09-01

    State-of-the-art as-received (112)B CdZnTe substrates have been examined for surface impurity contamination and polishing residue. Two 4 cm × 4 cm and one 6 cm × 6 cm (112)B state-of-the-art as-received CdZnTe wafers were analyzed. A maximum surface impurity concentration of Al = 1.7 × 1015 atoms cm-2, Si = 3.7 × 1013 atoms cm-2, Cl = 3.12 × 1015 atoms cm-2, S = 1.7 × 1014 atoms cm-2, P = 1.1 × 1014 atoms cm-2, Fe = 1.0 × 1013 atoms cm-2, Br = 1.2 × 1014 atoms cm-2, and Cu = 4 × 1012 atoms cm-2 was observed on the as-received CdZnTe wafers. CdZnTe particulates and residual SiO2 polishing grit were observed on the surface of the as-received (112)B CdZnTe substrates. The polishing grit/CdZnTe particulate density on CdZnTe wafers was observed to vary across a 6 cm × 6 cm wafer from ˜4 × 107 cm-2 to 2.5 × 108 cm-2. The surface impurity and damage layer of the (112)B CdZnTe wafers dictate that a molecular beam epitaxy (MBE) preparation etch is required. The contamination for one 4 cm × 4 cm and one 6 cm × 6 cm CdZnTe wafer after a standard MBE Br:methanol preparation etch procedure was also analyzed. A maximum surface impurity concentration of Al = 2.4 × 1015 atoms cm-2, Si = 4.0 × 1013 atoms cm-2, Cl = 7.5 × 1013 atoms cm-2, S = 4.4 × 1013 atoms cm-2, P = 9.8 × 1013 atoms cm-2, Fe = 1.0 × 1013 atoms cm-2, Br = 2.9 × 1014 atoms cm-2, and Cu = 5.2 × 1012 atoms cm-2 was observed on the MBE preparation-etched CdZnTe wafers. The MBE preparation-etched surface contamination consists of Cd(Zn)Te particles/flakes. No residual SiO2 polishing grit was observed on the (112)B surface.

  15. Noise properties of Pb/Cd-free thick film resistors

    International Nuclear Information System (INIS)

    Stadler, Adam Witold; Kolek, Andrzej; Zawislak, Zbigniew; Mleczko, Krzysztof; Jakubowska, Malgorzata; Kielbasinski, Konrad Rafal; Mlozniak, Anna

    2010-01-01

    Low-frequency noise spectroscopy has been used to examine noise properties of Pb/Cd-free RuO 2 - and CaRuO 3 -based thick films screen printed on alumina substrates. Experiments were performed in the temperature range 77-300 K and the frequency range 0.5-5000 Hz with multiterminal devices. The measured noise has been recognized as resistance noise that consists of background 1/f noise and components generated by several thermally activated noise sources (TANSs) of different activation energies. The total noise has been composed of the contributions generated in the resistive layer and in the resistive/conductive layers interface. These noise sources are non-uniformly distributed in the resistor volume. Noise intensity of new-resistive layers has been described by the noise parameter C bulk . Pb/Cd-free layers turned out to be noisier than their Pb-containing counterparts; however, the removal of Pb and Cd from resistive composition is hardly responsible for the increase in the noise. In the case of RuO 2 layers noise increases most likely due to larger grain size of RuO 2 powder used to prepare resistive pastes. Information on the quality of the resistive-to-conductive layers interface occurred to be stored in the values of noise parameter C int . Pb/Cd-free RuO 2 -based resistive pastes form well-behaved interfaces with various Ag-based conductive pastes. In contrast, CaRuO 3 -based paste forms bad contacts with AgPd terminations because the density of TANSs increases in the interface area.

  16. Phytoextraction of 55-year-old wastewater-irrigated soil in a Zn-Pb mine district: effect of plant species and chelators.

    Science.gov (United States)

    Tai, YiPing; Yang, YuFen; Li, ZhiAn; Yang, Yang; Wang, JiaXi; Zhuang, Ping; Zou, Bi

    2017-07-16

    Untreated water from mining sites spreads heavy metal contamination. The present study assessed the phytoextraction performance of heavy metal-accumulating plants and the effects of chemical chelators on cadmium (Cd), lead (Pb), zinc (Zn), and copper (Cu) removal from paddy fields that have been continuously irrigated with mining wastewater from mines for 55 years. Outdoor pot experiments showed that the total Pb, Zn, and Cd content was lower in the rhizosphere soil of Amaranthus hypochondriacus than in that of Sedum alfredii, Solanum nigrum, and Sorghum bicolor. The aboveground biomass (dry weight) and relative growth rate of A. hypochondriacus were significantly higher than that of the other three species (P phytoextraction effect.

  17. Electrical properties of MIS devices on CdZnTe/HgCdTe

    Science.gov (United States)

    Lee, Tae-Seok; Jeoung, Y. T.; Kim, Hyun Kyu; Kim, Jae Mook; Song, Jinhan; Ann, S. Y.; Lee, Ji Y.; Kim, Young Hun; Kim, Sun-Ung; Park, Mann-Jang; Lee, S. D.; Suh, Sang-Hee

    1998-10-01

    In this paper, we report the capacitance-voltage (C-V) properties of metal-insulator-semiconductor (MIS) devices on CdTe/HgCdTe by the metalorganic chemical vapor deposition (MOCVD) and CdZnTe/HgCdTe by thermal evaporation. In MOCVD, CdTe layers are directly grown on HgCdTe using the metal organic sources of DMCd and DiPTe. HgCdTe layers are converted to n-type and the carrier concentration, ND is low 1015 cm-3 after Hg-vacancy annealing at 260 degrees Celsius. In thermal evaporation, CdZnTe passivation layers were deposited on HgCdTe surfaces after the surfaces were etched with 0.5 - 2.0% bromine in methanol solution. To investigate the electrical properties of the MIS devices, the C-V measurement is conducted at 80 K and 1 MHz. C-V curve of MIS devices on CdTe/HgCdTe by MOCVD has shown nearly flat band condition and large hysteresis, which is inferred to result from many defects in CdTe layer induced during Hg-vacancy annealing process. A negative flat band voltage (VFB approximately equals -2 V) and a small hysteresis have been observed for MIS devices on CdZnTe/HgCdTe by thermal evaporation. It is inferred that the negative flat band voltage results from residual Te4+ on the surface after etching with bromine in methanol solution.

  18. Growth And Characterization Of LPE CdHgTe/CdZnTe/CdZnTe Structure

    Science.gov (United States)

    Pelliciari, B.; Chamonal, J. P.; Destefanis, G. L.; Dicioccio, L.

    1988-05-01

    The liquid phase epitaxial technique is used to grow Hgl_x Cdx Te (x = .23) from a Te - rich solution onto a Cdl_y ZnyTe (y = .04) buffer layer grown from a Te-rich solution onto a Cdi_yZnyTe bulk substrate in an open tube multibin horizontal slider apparatus.Growth conditions and physical characterizations of both the buffer layer and the CdHgTe layer are given ; electrical properties of the CdHgTe layer are also presen-ted. PV detectors were successfully obtained on such a structure using an ion-implanted technology and their characteristics at 77 K for a 10.1 ,um cut-off wavelength are given.

  19. Thermal and electrical conductivities of Cd-Zn alloys

    International Nuclear Information System (INIS)

    Saatci, B; Ari, M; Guenduez, M; Meydaneri, F; Bozoklu, M; Durmus, S

    2006-01-01

    The composition and temperature dependences of the thermal and electrical conductivities of three different Cd-Zn alloys have been investigated in the temperature range of 300-650 K. Thermal conductivities of the Cd-Zn alloys have been determined by using the radial heat flow method. It has been found that the thermal conductivity decreases slightly with increasing temperature and the data of thermal conductivity are shifting together to the higher values with increasing Cd composition. In addition, the electrical measurements were determined by using a standard DC four-point probe technique. The resistivity increases linearly and the electrical conductivity decreases exponentially with increasing temperature. The resistivity and electrical conductivity are independent of composition of Cd and Zn. Also, the temperature coefficient of Cd-Zn alloys has been determined, which is independent of composition of Cd and Zn. Finally, Lorenz number has been calculated using the thermal and electrical conductivity values at 373 and 533 K. The results satisfy the Wiedemann-Franz (WF) relation at T 373 K), the WF relation could not hold and the phonon component contribution of thermal conductivity dominates the thermal conduction

  20. Directional solidification of filamentary shapes of Pb--Cd and Pb--Sn eutectic alloys

    International Nuclear Information System (INIS)

    Dhindaw, B.K.; Verhoeven, J.D.; Spencer, C.R.; Gibson, E.D.

    1978-01-01

    Eutectic alloys of Pb--Cd and Pb--Sn were directionally solidified as thin filamentary strips contained in stainless steel and quartz capillaries. As the solidification rate increased the filament width, w, had to be reduced to maintain complete alignment of the lamellae clear across the filament. It was determined that in order to achieve complete alignment the ratio of filament width to lamellar spacing, w/lambda had to be less than about 30. Experiments were carried out at rates of 2-400 μm/s and at temperature gradients of 130 and 320 0 C/cm

  1. The quadrupole moments of Cd and Zn isotopes - an apology

    Science.gov (United States)

    Haas, H.; Barbosa, M. B.; Correia, J. G.

    2016-12-01

    In 2010 we presented an update of the nuclear quadrupole moments (Q) for the Cd and Zn isotopes, based essentially on straightforward density functional (DF) calculations (H. Haas and J.G. Correia, Hyperfine Interact 198, 133-137 (2010)). It has been apparent for some years that the standard DF procedure obviously fails, however, to reproduce the known electric-field gradient (EFG) for various systems, typical cases being Cu2O, As and Sb, and the solid halogens. Recently a cure for this deficiency has been found in the hybrid DF technique. This method is now applied to solid Cd and Zn, and the resultant quadrupole moments are about 15 % smaller than in our earlier report. Also nuclear systematics, using the recently revised values of Q for the long-lived 11/2 isomers in111Cd to129Cd, together with earlier PAD data for107,109Cd, leads to the same conclusion. In addition, EFG calculations for the cadmium dimethyl molecule further support the new values: Q(111Cd, 5/2+) = .683(20) b, Q(67Zn, gs) = .132(5) b. This implies, that the value for the atomic EFG in the 3it {P}1 state of Zn must be revised, as it has been for Cd.

  2. Soil-plant abstract of heavy metals in Pb-Zn mining sites from Alcudia Valley (South Spain)

    Science.gov (United States)

    López-Berdonces, Miguel; Higueras, Pablo; Esbrí, Jose Maria; González-Corrochano, Beatríz; García-Noguero, Eva Mª; Martínez-Coronado, Alba; Fernandez-Calderón, Sergio; García-Noguero, Carolina

    2013-04-01

    Soil-plant transfer of heavy metals in Pb-Zn mining sites from Alcudia Valley (South Spain). Authors: Miguel A. López-Berdonces¹; Pablo Higueras¹; Jose María Esbrí¹; Beatriz González-Corrochano¹; Eva Mª García- Noguero¹; Alba Martínez Coronado¹; Sergio Fernández-Calderón¹; Carolina García-Noguero¹ ¹Instituto de Geología Aplicada, Universidad Castilla la Mancha, Pza. Manuel Meca, 1. 13400 Almadén, Spain. Alcudia Valley is a vast territory recently declared Natural Park, located in South of Spain. It is an area rich in mineral deposits of Zn and Pb and mining exists since the first millennium BC., having its highest ore production between mid-nineteenth century and the middle of the twentieth. This area has been selected because has more than 120 abandoned mines without remediation actions, with dumps and tailings with high contents of zinc and lead sulfides, and Cu, Ag, Cd, As, Sb in minor concentrations. In this study we determinate the transfer rate of these metals from soils to plants represented by oak leaves (Quercus ilex), because this specie is common within the selected area. To evaluate the soil-plant transfer were studied the correlation of contents, total and extractable, in soil-leaves. Extractable fraction was done by for different methods in water, EPA 1312 sulfuric acid: nitric acid 60:40 v., Ammonium Acetate and EDTA. To establish the correlation between heavy metals from soils to plants is necessary to know the contents of these and bioavailable content in soil. Three areas (S. Quintín, Romanilla, Bombita) were selected, taking 24 samples of soils and leaves. Analyzed leaves by XRF showed that Mn, Pb, Zn and Mo in S.Quintin and Romanilla, Mn, Pb in Bombita, exceeded the toxicity threshold. The same samples analyzed by ICP show us the toxicity threshold is exceeded Pb, Zn and Hg in S.Quintin, and Pb in Romanilla. The heavy metal content in leaves compared between two techniques analytical gives an acceptable correlation Zn - Pb

  3. Tunable zinc interstitial related defects in ZnMgO and ZnCdO films

    International Nuclear Information System (INIS)

    Li, Wanjun; Qin, Guoping; Fang, Liang; Ye, Lijuan; Wu, Fang; Ruan, Haibo; Zhang, Hong; Kong, Chunyang; Zhang, Ping

    2015-01-01

    We report tunable band gap of ZnO thin films grown on quartz substrates by radio frequency magnetron sputtering. The zinc interstitial (Zn i ) defects in ZnO films were investigated by X-ray diffraction, Raman scattering, Auger spectra, first-principle calculations, and Hall measurement. Undoped ZnO film exhibits an anomalous Raman mode at 275 cm −1 . We first report that 275 cm −1 mode also can be observed in ZnO films alloyed with Mg and Cd, whose Raman intensities, interestingly, decrease and increase with increasing Mg and Cd alloying content, respectively. Combined with the previous investigations, it is deduced that 275 cm −1 mode is attributed to Zn i related defects, which is demonstrated by our further experiment and theoretical calculation. Consequently, the concentration of Zn i related defects in ZnO can be tuned by alloying Mg and Cd impurity, which gives rise to different conductivity in ZnO films. These investigations help to further understand the controversial origin of the additional Raman mode at 275 cm −1 and also the natural n-type conductivity in ZnO

  4. Tunable zinc interstitial related defects in ZnMgO and ZnCdO films

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wanjun; Qin, Guoping [State Key Laboratory of Mechanical Transmission, College of Physics, Chongqing University, Chongqing 401331 (China); Key Laboratory of Optoelectronic Functional Materials of Chongqing, College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing, Chongqing 401331 (China); Fang, Liang, E-mail: lfang@cqu.edu.cn, E-mail: kchy@163.com; Ye, Lijuan; Wu, Fang [State Key Laboratory of Mechanical Transmission, College of Physics, Chongqing University, Chongqing 401331 (China); Ruan, Haibo [Research Center for Materials Interdisciplinary Sciences, Chongqing University of Arts and Sciences, Chongqing 402160 (China); Zhang, Hong; Kong, Chunyang, E-mail: lfang@cqu.edu.cn, E-mail: kchy@163.com; Zhang, Ping [Key Laboratory of Optoelectronic Functional Materials of Chongqing, College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing, Chongqing 401331 (China)

    2015-04-14

    We report tunable band gap of ZnO thin films grown on quartz substrates by radio frequency magnetron sputtering. The zinc interstitial (Zn{sub i}) defects in ZnO films were investigated by X-ray diffraction, Raman scattering, Auger spectra, first-principle calculations, and Hall measurement. Undoped ZnO film exhibits an anomalous Raman mode at 275 cm{sup −1}. We first report that 275 cm{sup −1} mode also can be observed in ZnO films alloyed with Mg and Cd, whose Raman intensities, interestingly, decrease and increase with increasing Mg and Cd alloying content, respectively. Combined with the previous investigations, it is deduced that 275 cm{sup −1} mode is attributed to Zn{sub i} related defects, which is demonstrated by our further experiment and theoretical calculation. Consequently, the concentration of Zn{sub i} related defects in ZnO can be tuned by alloying Mg and Cd impurity, which gives rise to different conductivity in ZnO films. These investigations help to further understand the controversial origin of the additional Raman mode at 275 cm{sup −1} and also the natural n-type conductivity in ZnO.

  5. Geochemistry of the Patricia Zn-Pb-Ag Deposit (paguanta, NE Chile)

    Science.gov (United States)

    Chinchilla Benavides, D.; Merinero Palomares, R.; Piña García, R.; Ortega Menor, L.; Lunar Hernández, R.

    2013-12-01

    The Patricia Zn-Pb-Ag ore deposit is located within the Paguanta mining project, situated at the northern end of the Andean Oligocene Porphyry Copper Belt of Chile. The sulfide mineralization occurs as W-E oriented veins hosted in volcanic rocks, mainly andesite (pyroclastic, ash and lavas), of Upper Cretaceous to Middle Tertiary age. The ore mineralogy (obtained by EMPA analyses) comprises in order of abundance, pyrite, sphalerite (5.5 - 10.89 wt % Fe, 9.8-19 % molar FeS and 0.52 wt % Cd), galena, arsenopyrite, chalcopyrite and Ag-bearing sulfosalts. The veins show a zoned and banded internal structure with pyrite at the edges and sphalerite in the center. The Ag occurs mostly as Ag-Cu-Sb sulfosalts, in order of abundance: series freibergite - argentotennantite -polybasite and stephanite. Other minor Ag phases such as argentite, pyrargirite and diaphorite were also identified. These Ag phases are typically associated with the base-metal sulfides. Freibergite occurs filling voids within sphalerite, chalcopyrite and at the contact between sphalerite and galena. Polybasite, stephanite, pyrargirite and argentite are mostly in close association with freibergite. In the case of diaphorite, it commonly occurs filling voids between galena crystals or as inclusions within galena. Some minor Ag-bearing sulfosalts are also identified between pyrite crystals. The alteration minerals are dominated by chlorite, illite and kaolinite. The gangue minerals consist of quartz and carbonates identified by XRD as kutnahorite. We obtained linear correlation statistically significant only for Ag, As Au, Cd, Cu, Pb, Sb and Zn and therefore we generated an enhanced scatter plot matrix of these elements. Bulk rock analyses (ICP/MS and XRF) of drill cores show that Ag is strongly and positively correlated with Pb and As, moderately with Cd, Sb, Au and Zn and weakly with Cu, while Au is moderately and positively correlated with Ag, As, Cd, Sb and Zn and weakly with Cu and Pb. These results

  6. Optical phonons in PbTe/CdTe multilayer heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Novikova, N. N.; Yakovlev, V. A. [Russian Academy of Sciences, Institute for Spectroscopy (Russian Federation); Kucherenko, I. V., E-mail: kucheren@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Karczewski, G. [Polish Academy of Sciences, Institute of Physics (Poland); Aleshchenko, Yu. A.; Muratov, A. V.; Zavaritskaya, T. N.; Melnik, N. N. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2015-05-15

    The infrared reflection spectra of PbTe/CdTe multilayer nanostructures grown by molecular-beam epitaxy are measured in the frequency range of 20–5000 cm{sup −1} at room temperature. The thicknesses and high-frequency dielectric constants of the PbTe and CdTe layers and the frequencies of the transverse optical (TO) phonons in these structures are determined from dispersion analysis of the spectra. It is found that the samples under study are characterized by two TO phonon frequencies, equal to 28 and 47 cm{sup −1}. The first frequency is close to that of TO phonons in bulk PbTe, and the second is assigned to the optical mode in structurally distorted interface layers. The Raman-scattering spectra upon excitation with the radiation of an Ar{sup +} laser at 514.5 nm are measured at room and liquid-nitrogen temperatures. The weak line at 106 cm{sup −1} observed in these spectra is attributed to longitudinal optical phonons in the interface layers.

  7. ADSORPSI LOGAM SENG (Zn DAN TIMBAL (Pb PADA LIMBAH CAIR INDUSTRI KERAMIK OLEH TANAH LIAT

    Directory of Open Access Journals (Sweden)

    Cindy Rianti Priadi

    2014-05-01

    Full Text Available ADSORPTION OF ZINC AND LEAD FROM CERAMIC WASTEWATER USING CLAY. Ceramic industry generates glaze wastewater and clay waste. Glaze wastewater contains heavy metal from ceramic painting process which can potentially cause severe pollution problem. Glaze wastewater from PT.X typically contains Cd (0.013 mg/L; Cu (0.033 mg/L; Pb (1.20 mg/L; and Zn (7.00 mg/L. Clay waste used as adsorbent to reduce heavy metal amount in glaze wastewater. The present study investigates in bench scale and uses batch adsorption method to determine effective  adsorbent amount and contact time in removing heavy metals in glaze wastewater in order to fulfill the discharge requirement based on regulation of Minister of Environment No.16/2008concerning effluent water standard for ceramic industries. The results showed that the effective adsorbent amount and contact time respectively are 5 g/L and 15 minutes with pH 8 and stirring speed of 150 rpm. Concentration of heavy metal adsorbed are 0,614 mg/L and 2,07 mg/L for lead (Pb and zinc (Zn with removal efficiency up to 61.0% for Pb and 9.8% for Zn.From this study clay waste could be potentially used as an adsorbent to reduce heavy metal amount in glaze wastewater. Keywords: adsorption, clay waste, heavy metals Abstrak Industri keramik menghasilkan limbah glasir dan limbah tanah liat. Limbah glasir mengandung logam berat yang berasal dari proses pewarnaan keramik dan berpotensi mencemari lingkungan. Kandungan logam berat pada limbah glasir PT.X yaitu Cd (0,013 mg/L; Cu (0,033 mg/L; Pb (1,20 mg/L; dan Zn (7,00 mg/L. Limbah tanah liat digunakan sebagai adsorben yang berguna mengurangi kadar logam berat pada limbah glasir.Penelitian ini dilakukan dalam skala laboratorium menggunakan metode batch adsorpsi untuk menentukan dosis adsorben dan waktu kontak yang efektif dalam mengolah limbah glasir agar memenuhi persyaratan Peraturan Menteri Negara Lingkungan Hidup Nomor 16 Tahun 2008 tentang baku mutu air limbah bagi usaha dan

  8. T-x-y diagrams for reciprocal systems PbX + CdI2 = CdX + PbI2 (X=S, Se, Te)

    International Nuclear Information System (INIS)

    Odin, I.N.

    2001-01-01

    The present research is undertaken in search of the new complex phases with interesting physical properties. The synthesized samples was analyzed by differential thermal, X-ray diffraction and microstructural methods. The diagonal cross-section CdTe - PbI 2 of the mutual PbTe + CdI 2 = CdTe + PbI 2 system is stable. The T-x phase diagram of the CdTe - PbI 2 system possess eutectic type, the coordinates of eutectic point is 657 ± 2 K, 15 ± 1 mol. % of CdTe. The lead iodide based solid solutions with the mixed structure and the CdTe based solid solutions take place in the equilibria. Solid CdTe dissolves 0.2 mol. % PbI 2 . The fields of the primary crystallization of the CdTe, Pb 1-x Cd x I 2 , PbTe based solid solutions are on the liquidus surface [ru

  9. [Stabilization Treatment of Pb and Zn in Contaminated Soils and Mechanism Studies].

    Science.gov (United States)

    Xie, Wei-qiang; Li, Xiao-mingi; Chen, Can; Chen, Xun-feng; Zhong, Yu; Zhong, Zhen-yu; Wan, Yong; Wang, Yan

    2015-12-01

    In the present work, the combined application of potassium dihydrogen phosphate, quick lime and potassium chloride was used to immobilize the Pb and Zn in contaminated soils. The efficiency of the process was evaluated through leaching tests and Tessier sequential extraction procedure. The mechanism of stabilization was analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) to reveal the mechanism of stabilization. The results showed that the stabilizing efficiency of Pb contaminated soils was above 80% and the leaching concentrations of Pb, Zn were far below the threshold when the ratio of exogenous P and soil (mol · mol⁻¹) was 2:1-4: 1, the dosing ratio of CaO was 0.1%-0.5% ( mass fraction) and the dosage of potassium chloride was 0.02-0. 04 mol. Meanwhile, Pb and Zn in soil were transformed from the exchangeable fraction into residual fraction, which implied that the migration of Pb, Zn in soil could be confined by the stabilization treatment. XRD and SEM analysis revealed that Ca-P-Pb precipitation, lead orthophosphate [PbHP0₄, Pb₃ (PO₄)₂], pyromorphite (Pb-PO₄-Cl/OH) and mixed heavy metal deposits (Fe-PO₄- Ca-Pb-Zn-OH) could be formed after solidification/stabilization in which Pb and Zn could be wrapped up to form a solidified composition and to prevent leaching.

  10. Investigation of the optoelectronic behavior of Pb-doped CdO nanostructures

    Science.gov (United States)

    Eskandari, Abdollah; Jamali-Sheini, Farid; Cheraghizade, Mohsen; Yousefi, Ramin

    2018-03-01

    Un- and lead (Pb)-doped cadmium oxide (CdO) semiconductor nanostructures were synthesized by a sonochemical method to study their physical properties. The obtained X-ray diffraction (XRD) patterns indicated cubic CdO crystalline structures for all samples and showed that the crystallite size of CdO increases with Pb addition. Scanning electron microscopy (SEM) images of the nanostructures illustrated agglomerated oak-like particles for the Pb-doped CdO nanostructures. Furthermore, optical studies suggested that the emission band gap energy of the CdO nanostructures lies in the range of 2.27-2.38 eV and crystalline defects increase by incorporation of Pb atoms in the CdO crystalline lattice. In addition, electrical experiments declared that the n-type electrical nature of the un- and Pb-doped CdO nanostructures and the minimum of Pb atoms lead to a high carrier concentration.

  11. Effect of ZnO and PbO/ZnO on structural and thermal properties of tellurite glasses

    International Nuclear Information System (INIS)

    Ramamoorthy, Raj Kumar; Bhatnagar, Anil K

    2015-01-01

    Highlights: • Structural units/linkages variation of TeO 2 -ZnO and TeO 2 -ZnO-PbO glasses was studied. • Structural arrangements of TeO 2 -ZnO glasses are rich in Te-O-Te network. • A mixture of Te-O-Te and Te-O-Pb networks is identified in TeO 2 -ZnO-PbO glasses. • Changes in thermal parameters T g and T o are correlated with the structural variations. • 15PbO and 20PbO samples of TeO 2 -ZnO-PbO glasses show large thermal stability. - Abstract: Two series of glasses, (100 − x)TeO 2 -xZnO (x = 20, 25, 30, 35) and 70TeO 2 -(30 − y)ZnO-yPbO (y = 5, 10, 15, 20), referred as TZ and TZP, respectively, were prepared by a melt quenching technique and characterized by X-ray diffraction (XRD), density, refractive index, Raman scattering and differential scanning calorimetry (DSC) to observe the changes in their properties as a function of ZnO and PbO/ZnO. Variations in individual structural units/linkages in these glasses are derived from the de-convoluted Raman spectra. The glass transition (T g ) and onset of crystallization (T o ) temperatures are determined from DSC isothermal scans. It is observed that the thermal stability (ΔT = T o − T g ) decreases for TZ glasses with increase in x, while it increases for TZP glasses with increase in y. Changes in thermal parameters of these glasses are correlated with the structural variation as a function of ZnO and PbO/ZnO ratio to determine the effect of substitution/addition of metal oxide, ZnO and PbO, to TeO 2 and TeO 2 -ZnO glasses

  12. One-step synthesis of PbSe-ZnSe composite thin film

    Directory of Open Access Journals (Sweden)

    Abe Seishi

    2011-01-01

    Full Text Available Abstract This study investigates the preparation of PbSe-ZnSe composite thin films by simultaneous hot-wall deposition (HWD from multiple resources. The XRD result reveals that the solubility limit of Pb in ZnSe is quite narrow, less than 1 mol%, with obvious phase-separation in the composite thin films. A nanoscale elemental mapping of the film containing 5 mol% PbSe indicates that isolated PbSe nanocrystals are dispersed in the ZnSe matrix. The optical absorption edge of the composite thin films shifts toward the low-photon-energy region as the PbSe content increases. The use of a phase-separating PbSe-ZnSe system and HWD techniques enables simple production of the composite package.

  13. Photoluminescence characteristics of Pb-doped, molecular-beam-epitaxy grown ZnSe crystal layers

    International Nuclear Information System (INIS)

    Mita, Yoh; Kuronuma, Ryoichi; Inoue, Masanori; Sasaki, Shoichiro; Miyamoto, Yoshinobu

    2004-01-01

    The characteristic green photoluminescence emission and related phenomena in Pb-doped, molecular-beam-epitaxy (MBE)-grown ZnSe crystal layers were investigated to explore the nature of the center responsible for the green emission. The intensity of the green emission showed a distinct nonlinear dependence on excitation intensity. Pb-diffused polycrystalline ZnSe was similarly examined for comparison. The characteristic green emission has been observed only in MBE-grown ZnSe crystal layers with moderate Pb doping. The results of the investigations on the growth conditions, luminescence, and related properties of the ZnSe crystal layers suggest that the green emission is due to isolated Pb replacing Zn and surrounded with regular ZnSe lattice with a high perfection

  14. Radionuclide X-ray fluorescence determination of Mn, Fe, Cu, Zn and Pb in wastewaters and sludges from wastewater treatment plants in Bratislava (SR)

    International Nuclear Information System (INIS)

    Harangozo, M.; Toelgyessy, J.

    1997-01-01

    Radiometric X-ray fluorescence analysis was used for the determination of Mn, Fe, Cu, Zn and Pb in wastewater and sludges from three wastewater treatment plants in Bratislava (SR). Metals were determined in wastewaters after preconcentration by 8-hydroxyquinoline and in sludges by drying and pressing to pellets. 238 Pu and 109 Cd was used for excitation of fluorescence radiation. (author)

  15. Leakage current measurements on pixelated CdZnTe detectors

    NARCIS (Netherlands)

    Dirks, B.; Blondel, C.; Daly, F.; Gevin, O.; Limousin, O.; Lugiez, F.

    2006-01-01

    In the field of the R&D of a new generation hard X-ray cameras for space applications we focus on the use of pixelated CdTe or CdZnTe semiconductor detectors. They are covered with 64 (0.9×0.9 mm2) or 256 (0.5×0.5 mm2) pixels, surrounded by a guard ring and operate in the energy ranging from several

  16. Accumulation of Heavy Metals (Pb, Cd, V) in Sediment, roots and ...

    African Journals Online (AJOL)

    Michael Horsfall

    info and www.bioline.org.br/ja. Accumulation of Heavy Metals (Pb, Cd, V) in Sediment, roots and leaves of ... ABSTRACT: Sirik mangrove forests harbour two species, Avicennia marina and .... Based on the soil critical concentration value of Pb.

  17. Liquid petroleum gas sensing application of ZnO/CdO:ZnO nanocomposites at low temperature

    Science.gov (United States)

    Rajput, Jeevitesh K.; Pathak, T. K.; Kumar, V.; Swart, H. C.; Purohit, L. P.

    2018-04-01

    ZnO and CdO:ZnO nanoparticles are synthesized by sol-gel precipitation method. The structural analysis shows composite structure for CdO:ZnO nanoparticles with (002) and (111) phase. The SEM images show wedge like morphology and 3-D hexagonal morphology with ˜110 nm in size. The uniform growth of CdO:ZnO nanoparticles were observed in EDS element mapping image. LPG sensing was observed for CdO:ZnO nanoparticle with rapid sensing response 8.69% at operating temperature 50°C. This sensing response can be accounted due by absorption ions reactions at low operating temperature.

  18. [Effects of soil properties on the stabilization process of cadmium in Cd alone and Cd-Pb contaminated soils].

    Science.gov (United States)

    Wu, Man; Xu, Ming-Gang; Zhang, Wen-Ju; Wu, Hai-Wen

    2012-07-01

    In order to clarify the effects of soil properties on the stabilization process of the cadmium (Cd) added, 11 different soils were collected and incubated under a moisture content of 65%-70% at 25 degrees C. The changes of available Cd contents with incubation time (in 360 days) in Cd and Cd-Pb contaminated treatments were determined. The stabilization process was simulated using dynamic equations. The results showed that after 1.0 mg x kg(-1) Cd or 500 mg x kg(-1) Pb + 1.0 mg x kg(-1) Cd were added into the soil, the available Cd content decreased rapidly during the first 15 days, and then the decreasing rate slowed down, with an equilibrium content reached after 60 days' incubation. In Cd-Pb contaminated soils, the presence of Pb increased the content of available Cd. The stabilization process of Cd could be well described by the second-order equation and the first order exponential decay; meanwhile, dynamic parameters including equilibrium content and stabilization velocity were used to characterize the stabilization process of Cd. These two key dynamic parameters were significantly affected by soil properties. Correlation analysis and stepwise regression suggested that high pH and high cation exchange capacity (CEC) significantly retarded the availability of Cd. High pH had the paramount effect on the equilibrium content. The stabilization velocity of Cd was influenced by the soil texture. It took shorter time for Cd to get stabilized in sandy soil than in the clay.

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

    International Nuclear Information System (INIS)

    Gessert, T.A.; Asher, S.; Johnston, S.; Young, M.; Dippo, P.; Corwine, C.

    2007-01-01

    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 i ) and oxygen on Te (O 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

  20. Gomphrena claussenii, a Zn and Cd hyperbioindicator species

    NARCIS (Netherlands)

    Tomaz Villafort Carvalho, M.

    2016-01-01

    Gomphrena claussenii, a Zn and Cd hyperbioindicator species

    A small group of plant species called metallophytes have evolved the ability to grow in highly metal-enriched soils that are toxic to other plants. Some of these metal-tolerant species have evolved the ability to accumulate high

  1. Synthesis and Structural Studies of Nanocrystalline Cd Zn Fe O

    African Journals Online (AJOL)

    NICO

    The synthesis of Cd0.3Zn0.7Fe2O4 nanoparticles has been achieved by a simple thermal decomposition method from the inorganic ... pure and doped spinel ferrite nanopowders. ... K. Kalimuthu, S.C. Rangasamy and M. Rakkiyasamy,. 91.

  2. Gamma Spectroscopy with Pixellated CdZnTe Gamma Detectors

    International Nuclear Information System (INIS)

    Shor, A.; Mardor, I.; Eisen, Y.

    2002-01-01

    Pixellated CdZnTe detectors are good candidates for room temperature gamma detection requiring spectroscopic performance with imaging capabilities. The CdZnTe materials possess high resistivity and good electron charge transport properties. The poor charge transport for the holes inherent in the CdZnTe material can be circumvented by fabricating the electrodes in any one of a number of structures designed for unipolar charge detection[1]. Recent interest in efficient gamma detection at relatively higher gamma energies has imposed more stringent demands on the CdZnTe material and on detector design and optimization. We developed at Soreq a technique where signals from all pixels and from the common electrode are processed, and then a correction is applied for improving the energy resolution and the photopeak efficiency. For illumination with an un-collimated 133 Ba source , we obtain a combined detector energy resolution of 5.0 % FWHM for the 81 keV peak, and 1.5 % FWHM for the 356 keV peak. We discuss the importance of detector material with high electron (μτ) e for thick Pixellated detectors

  3. 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.

  4. Computer augumented modelling studies of Pb(II, Cd(II, Hg(II, Co(II, Ni(II, Cu(II and Zn(II complexes of L-glutamic acid in 1,2-propanediol–water mixtures

    Directory of Open Access Journals (Sweden)

    MAHESWARA RAO VEGI

    2008-12-01

    Full Text Available Chemical speciation of Pb(II, Cd(II, Hg(II, Co(II, Ni(II, Cu(II and Zn(II complexes of L-glutamic acid was studied at 303 K in 0–60 vol. % 1,2-propanediol–water mixtures, whereby the ionic strength was maintained at 0.16 mol dm-3. The active forms of the ligand are LH3+, LH2 and LH–. The predominant detected species were ML, ML2, MLH, ML2H and ML2H2. The trend of the variation in the stability constants with changing dielectric constant of the medium is explained based on the cation stabilizing nature of the co-solvents, specific solvent–water interactions, charge dispersion and specific interactions of the co-solvent with the solute. The effect of systematic errors in the concentrations of the substances on the stability constants is in the order alkali > > acid > ligand > metal. The bioavailability and transportation of metals are explained based on distribution diagrams and stability constants.

  5. Effect of short-term Zn/Pb or long-term multi-metal stress on physiological and morphological parameters of metallicolous and nonmetallicolous Echium vulgare L. populations.

    Science.gov (United States)

    Dresler, Sławomir; Wójciak-Kosior, Magdalena; Sowa, Ireneusz; Stanisławski, Grzegorz; Bany, Izabela; Wójcik, Małgorzata

    2017-06-01

    The aim of the study was to determine the response of metallicolous and nonmetallicolous Echium vulgare L. populations to chronic multi-metal (Zn, Pb, Cd) and acute Zn (200, 400 μM) and Pb (30, 60 μM) stress. Three populations of E. vulgare, one from uncontaminated and two from metal-contaminated areas, were studied. Two types of experiments were performed - a short-term hydroponic experiment with acute Zn or Pb stress and a long-term manipulative soil experiment with the use of soils from the sites of origin of the three populations. Growth parameters, such as shoot and root fresh weight and leaf area, as well as organic acid accumulation were determined. Moreover, the concentration of selected secondary metabolites and antioxidant capacity in the three populations exposed to Pb or Zn excess were measured. Both metallicolous populations generally achieved higher biomass compared with the nonmetallicolous population cultivated under metal stress in hydroponics or on metalliferous substrates. Plants exposed to Pb or Zn excess or contaminated soil substrate exhibited higher malate and citrate concentrations compared with the reference (no metal stress) plants. It was observed that Zn or Pb stress increased accumulation of allantoin, chlorogenic and rosmarinic acids, total phenolics, and flavonoids. Moreover, it was shown that Pb sequestration in the roots or Zn translocation to the shoots may play a role in enhanced metal tolerance of metallicolous populations under acute Pb/Zn stress. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. Characterisation of Redlen high-flux CdZnTe

    Science.gov (United States)

    Thomas, B.; Veale, M. C.; Wilson, M. D.; Seller, P.; Schneider, A.; Iniewski, K.

    2017-12-01

    CdZnTe is a promising material for the current generation of free electron laser light sources and future laser-driven γ-ray sources which require detectors capable of high flux imaging at X-ray and γ-ray energies (> 10 keV) . However, at high fluxes CdZnTe has been shown to polarise due to hole trapping, leading to poor performance. Novel Redlen CdZnTe material with improved hole transport properties has been designed for high flux applications. Small pixel CdZnTe detectors were fabricated by Redlen Technologies and flip-chip bonded to PIXIE ASICs. An XIA Digital Gamma Finder PIXIE-16 system was used to digitise each of the nine analogue signals with a timing resolution of 10 ns. Pulse shape analysis was used to extract the rise times and amplitude of signals. These were measured as a function of applied bias voltage and used to calculate the mobility (μ) and mobility-lifetime (μτ) of electrons and holes in the material for three identical detectors. The measured values of the transport properties of electrons in the high-flux-capable material was lower than previously reported for Redlen CdZnTe material (μeτe ~ 1 × 10-3 cm2V-1 and μe ~ 1000 cm2V-1s-1) while the hole transport properties were found to have improved (μhτh ~ 3 × 10-4 cm2V-1 and μh ~ 100 cm2V-1s-1).

  7. The giant Upper Yangtze Pb-Zn province in SW China: Reviews, new advances and a new genetic model

    Science.gov (United States)

    Zhou, Jia-Xi; Xiang, Zhen-Zhong; Zhou, Mei-Fu; Feng, Yue-Xing; Luo, Kai; Huang, Zhi-Long; Wu, Tao

    2018-04-01

    western Yangtze Block. The change of tectonic regimes from extension to compression after eruption of basalts of the ELIP, and then to extension during Early Mesozoic, facilitated extraction, migration, and excretion of ore-forming metals and associated fluids. Mixing of fluids and reduction geochemical barrier activated TSR, causing cyclical carbonate dissolution, CO2 degassing and recrystallization (namely carbonate buffer). All these processes triggered continuous precipitation of huge amounts of hydrothermal minerals. Underplating and eruption of ELIP basalts provided heat flow, fluids and volatiles, whereas the basalts acted as an impermeable and protective layer, and even as ore-hosting rocks. These Pb-Zn deposits have spatial and genetic association with igneous activities of the ELIP, and are characterized by high ore grades (>10 wt% Pb + Zn), high concentrations of associated metals (e.g. Cu, Ag, Ge, and Cd), and medium-low temperatures (usually Yangtze metallogenic province representing to a new type of Pb-Zn deposits that are hosted in platform carbonate sequences and formed within compressional zones of passive margin tectonic settings.

  8. Quantifying the signature of the industrial revolution from Pb and Cd isotopes in the Susquehanna Shale Hills Critical Zone Observatory

    Science.gov (United States)

    Ma, L.; Herndon, E.; Jin, L.; Sanchez, D.; Brantley, S. L.

    2013-12-01

    Anthropogenic forcings have dominated metal cycling in many environments. During the period of the industrial revolution, mining and smelting of ores and combustion of fossil fuels released non-negligible amounts of potentially toxic metals such as Pb, Cd, Mn, and Zn into the environment. The extent and fate of these metal depositions in soils during that period however, have not been adequately evaluated. Here, we combine Pb isotopes with Cd isotopes to trace the sources of metal pollutants in a small temperate watershed (Shale Hills) in Pennsylvania. Previous work has shown that Mn additions to soils in central PA was caused by early iron production, as well as coal burning and steel making upwind. Comparison of the Pb and Cd concentrations in the bedrock and soils from this watershed show that Pb and Cd in soils at Shale Hills are best characterized by addition profiles, consistent with atmospheric additions. Three soil profiles at Shale Hills on the same hillslope have very similar anthropogenic Pb inventories. Pb isotope results further reveal that the extensive use of local coals during iron production in early 19th century in Pennsylvania is most likely the anthropogenic Pb source for the surface soils at Shale Hills. Pb concentrations and isotope ratios were used to calculate mass balance and diffusive transport models in soil profiles. The model results further reveal that during the 1850s to 1920s, coal burning in local iron blasting furnaces significantly increased the Pb deposition rates to 8-14 μg cm-2 yr-1, even more than modern Pb deposition rates derived from the use of leaded gasoline in the 1940s to 1980s. Furthermore, Cd has a low boiling point (~760 °C) and easily evaporates and condenses. The evaporation and condensation processes could generate systematic mass-dependent isotope fractionation between Cd in coal burning products and the naturally occurring Cd in the sulfide minerals of coals. This fractionation indicates that Cd isotopes can

  9. On the interplay of point defects and Cd in non-polar ZnCdO films

    International Nuclear Information System (INIS)

    Zubiaga, A.; Reurings, F.; Tuomisto, F.; Plazaola, F.; García, J. A.; Kuznetsov, A. Yu.; Egger, W.; Zúñiga-Pérez, J.; Muñoz-Sanjosé, V.

    2013-01-01

    Non-polar ZnCdO films, grown over m- and r-sapphire with a Cd concentration ranging between 0.8% and 5%, have been studied by means of slow positron annihilation spectroscopy (PAS) combined with chemical depth profiling by secondary ion mass spectroscopy and Rutherford back-scattering. Vacancy clusters and Zn vacancies with concentrations up to 10 17 cm −3 and 10 18 cm −3 , respectively, have been measured inside the films. Secondary ion mass spectroscopy results show that most Cd stays inside the ZnCdO film but the diffused atoms can penetrate up to 1.3 μm inside the ZnO buffer. PAS results give an insight to the structure of the meta-stable ZnCdO above the thermodynamical solubility limit of 2%. A correlation between the concentration of vacancy clusters and Cd has been measured. The concentration of Zn vacancies is one order of magnitude larger than in as-grown non-polar ZnO films and the vacancy cluster are, at least partly, created by the aggregation of smaller Zn vacancy related defects. The Zn vacancy related defects and the vacancy clusters accumulate around the Cd atoms as a way to release the strain induced by the substitutional Cd Zn in the ZnO crystal.

  10. On the interplay of point defects and Cd in non-polar ZnCdO films

    Energy Technology Data Exchange (ETDEWEB)

    Zubiaga, A.; Reurings, F.; Tuomisto, F. [Department of Applied Physics, Aalto University, P.O. Box 11100, 00076 Aalto, Espoo (Finland); Plazaola, F. [Elektrizitatea eta Elektronika/Fisika Aplikatua II Sailak, Euskal Herriko Unibertsitatea, Posta Kutxatila 644, 48080 Bilbao (Spain); Garcia, J. A. [Fisika Aplikatua II Saila, Euskal Herriko Unibertsitatea, Posta Kutxatila 644, 48080 Bilbao (Spain); Kuznetsov, A. Yu. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, NO-0316 Oslo (Norway); Egger, W. [Inst. fuer Angewandte Physik und Messtechnik, Univ. der Bundeswehr Muenchen, 87755 Neubiberg (Germany); Zuniga-Perez, J. [CRHEA CNRS, F-06560 Valbonne (France); Munoz-Sanjose, V. [Dept. de Fisica Aplicada i Electromagnetisme, c/ Doctor Moliner 50, E-46100 Burjassot (Valencia) (Spain)

    2013-01-14

    Non-polar ZnCdO films, grown over m- and r-sapphire with a Cd concentration ranging between 0.8% and 5%, have been studied by means of slow positron annihilation spectroscopy (PAS) combined with chemical depth profiling by secondary ion mass spectroscopy and Rutherford back-scattering. Vacancy clusters and Zn vacancies with concentrations up to 10{sup 17} cm{sup -3} and 10{sup 18} cm{sup -3}, respectively, have been measured inside the films. Secondary ion mass spectroscopy results show that most Cd stays inside the ZnCdO film but the diffused atoms can penetrate up to 1.3 {mu}m inside the ZnO buffer. PAS results give an insight to the structure of the meta-stable ZnCdO above the thermodynamical solubility limit of 2%. A correlation between the concentration of vacancy clusters and Cd has been measured. The concentration of Zn vacancies is one order of magnitude larger than in as-grown non-polar ZnO films and the vacancy cluster are, at least partly, created by the aggregation of smaller Zn vacancy related defects. The Zn vacancy related defects and the vacancy clusters accumulate around the Cd atoms as a way to release the strain induced by the substitutional Cd{sub Zn} in the ZnO crystal.

  11. On the interplay of point defects and Cd in non-polar ZnCdO films

    Science.gov (United States)

    Zubiaga, A.; Reurings, F.; Tuomisto, F.; Plazaola, F.; García, J. A.; Kuznetsov, A. Yu.; Egger, W.; Zúñiga-Pérez, J.; Muñoz-Sanjosé, V.

    2013-01-01

    Non-polar ZnCdO films, grown over m- and r-sapphire with a Cd concentration ranging between 0.8% and 5%, have been studied by means of slow positron annihilation spectroscopy (PAS) combined with chemical depth profiling by secondary ion mass spectroscopy and Rutherford back-scattering. Vacancy clusters and Zn vacancies with concentrations up to 1017 cm-3 and 1018 cm-3, respectively, have been measured inside the films. Secondary ion mass spectroscopy results show that most Cd stays inside the ZnCdO film but the diffused atoms can penetrate up to 1.3 μm inside the ZnO buffer. PAS results give an insight to the structure of the meta-stable ZnCdO above the thermodynamical solubility limit of 2%. A correlation between the concentration of vacancy clusters and Cd has been measured. The concentration of Zn vacancies is one order of magnitude larger than in as-grown non-polar ZnO films and the vacancy cluster are, at least partly, created by the aggregation of smaller Zn vacancy related defects. The Zn vacancy related defects and the vacancy clusters accumulate around the Cd atoms as a way to release the strain induced by the substitutional CdZn in the ZnO crystal.

  12. CHEMICAL DETERMINATION OF HEAVY METALS IN PB AND ZN CONCENTRATES OF TREPÇA (KOSOVO AND CORRELATIONS COEFFI CIENTS STUDY BETWEEN CHEMICAL DATA

    Directory of Open Access Journals (Sweden)

    Fatbardh Gashi

    2017-03-01

    Full Text Available Kosovo ore deposits are located in the Trepça belt which extends for over 80 km. The concentrate produced by the flotation process of the Trepça metallurgical corporation contains a considerable quantity of valuable metals, such as Pb, Zn, Fe and minor accompanying metals such as Cd, Cu, As, Sb, Bi, Ag, Au, etc. The subject of this work was to assess the concentration of major and minor metals in lead and zinc concentrates of Trepça and to study the correlation coefficients between metals. Chemical determination of concentrates was performed by using atomic absorption spectroscopy (AAS. In the content on lead concentrate samples, the following were found: Pb>Fe>Zn> Ag> As>Sb>Cd. In the content of zinc concentrate, the following were found: Zn>Fe>Pb>Ag>As>Cd. The program “Statistica ver. 6.0” has been used for calculations of basic statistical parameters, relationships between data and cluster analysis of R-mode. R-mode cluster analysis on lead concentrate samples showed that Pb has the closest linkages with Fe and they form one branch of the dendogram. On the zinc concentrate samples, Zn has the closest linkages with Fe and they form one branch of the dendogram.

  13. Mineral phases identification inside an abandoned Zn/Pb mine

    International Nuclear Information System (INIS)

    Goienaga, N.; Carrero, J.A.; Olivares, M.; Castro, K.; Fernandez, L.A.; Madariaga, J.M.

    2009-01-01

    Complete text of publication follows. The aim of the work is the identification of the sulphurated phase's outbreak on an aragonite, dolomite and calcite-based original rock inside an abandoned mine. The studied Blende/Galena (ZnS/PbS) Mine, located in Lanestosa (Bizkaia, North of Spain) was operative until 1950. After decades, the area has only supported wild life and thus nowadays it could be considered as a polluted site which has become naturalized. The main alteration factors inside the mine are percolated water, gases come from the outside (CO 2 , O 2 ) and biological activities. Mining activities generates loads of ore minerals and unwanted materials that with the time impact the surrounding environment. The waste includes granular, broken rock and soils ranging in size from the fine sand to large boulders, with the content of fine material largely dependent on the nature of the formation and extraction methods employed during mining. Waste materials geochemistry varies widely from mine to mine and may vary significantly at individual mines over time as different lithologic strata are exposed and geochemical processes alter characteristics of the waste. In order to determine the finest mineral composition in the galleries, several samples were collected. Once dried in a fume hood and sieved, the portions below 250 μm were subjected to non-destructive Raman spectroscopic analysis. The measurements reflected the ore precursors (primary phases: Blende, and Galena), several primary carbonates (dolomite, calcite and aragonite) with secondary minerals in trace levels (Brookite, Libethenite, Fluorapatita, Anatasa, Quartz, Apatite, Augite, Diopside, Anthracite, Hematite, Cosalite, Epidote, Rutile) and transformation products, probably of recent formation (Smithsonite, Massicot, Plattnerite, Gypsum, Siderite, Mendiphite, Escorodite, Gauberite, Goethite or Mascagnite). The origin of the secondary mineral may be related to percolated rain and snow water. This

  14. Heavy metals and health risk assessment of arable soils and food crops around Pb-Zn mining localities in Enyigba, southeastern Nigeria

    Science.gov (United States)

    Obiora, Smart C.; Chukwu, Anthony; Davies, Theophilus C.

    2016-04-01

    This study determined the heavy metals concentration in arable soils and associated food crops around the Pb-Zn mines in Enyigba, Nigeria, and metal transfer factors were calculated. Air-dried samples of the soils and food crops were analyzed for 8 known nutritional and toxic heavy metals by Inductively Coupled Plasma - Mass Spectrometer (ICP-MS) method. Eighty seven percent of all the 20 sampled soils contain Pb in excess of the maximum allowable concentration (MAC) set by Canadian Environmental Quality Guideline (CCME) and European Union (EU) Standard, while Zn in thirty-one percent of the samples exceeded the CCME for MAC of 200 mg/kg. All the food crops, with the exception of yam tuber, contain Pb which exceeded the 0.43 mg/kg and 0.3 mg/kg MAC standards of EU and WHO/FAO respectively, with the leafy vegetables accumulating more Pb than the tubers. The metal transfer factors in the tubers and the leafy vegetables were in the order: Mo > Cu > Zn > Mn > As > Cd > Cr > Ni > Pb and Cd > Cu > Zn > Mn > Mo > As > Ni > Pb > Cr, respectively. Risk assessment studies revealed no health risk in surrounding populations for most of the heavy metals. However, Pb had a high health risk index (HRI) of 1.1 and 1.3, in adults and children, respectively for cassava tuber; Pb had HRI > 1 in lemon grass while Mn also had HRI > 1 in all the leafy vegetables for both adult and children. This high level of HRI for Pb and Mn is an indication that consumers of the food crops contaminated by these metals are at risk of health problems such as Alzheimers' disease and Manganism, associated with excessive intake of these metals. Further systematic monitoring of heavy metal fluxes in cultivable soils around the area of these mines is recommended.

  15. Novel red-emission of ternary ZnCdSe semiconductor nanocrystals

    Science.gov (United States)

    Chung, Shu-Ru; Wang, Kuan-Wen; Chen, Hong-Shuo; Chen, Hong-Hong

    2015-02-01

    The effect of chain lengths of fatty acids on the physical properties of CdSe and ZnCdSe semiconductor nanocrystals (NCs) synthesized by the colloidal chemistry procedure is investigated. The fatty acids, lauric acid (LA), and stearic acid (SA), with different lengths of carbon chains, are used to prepare CdSe and ZnCdSe NCs when hexyldecylamine (HDA) is applied as the sole surfactant. For CdSe-SA and ZnCdSe-SA, they have the same emission wavelength at 592 nm and the same particle size of 3.3 nm; however, their quantum yield (QY) is 75 and 16 %, respectively. In contrast, the emission wavelength of CdSe-LA and ZnCdSe-LA NCs is 609 and 615 nm, the particle size is about 3.5 and 4 nm under the same reaction time, and the QY of them are 33 and 59 %, respectively. The X-ray diffraction pattern shows that ZnCdSe NCs all have the wurtzite structure, and their main peaks are located between those of pure CdSe and ZnSe materials. The main phase of ZnCdSe-SA and ZnCdSe-LA is ZnSe and CdSe, respectively, implying that alloyed ZnCdSe NC can be prepared and ZnSe and CdSe phase can be promoted by SA and LA, respectively. Moreover, the QY of red-emission ZnCdSe-LA is higher than 50 %. These results suggest that the growth rate of CdSe as well as ZnCdSe NC can be enhanced by using LA as complex reagent and HDA as sole surfactant. It is expected that the reported effective synthetic strategy can be developed as a very practical, easy and not time-consuming approach to prepare red emissive NCs with high QY and high reproducibility.

  16. Metastable phases freezing from melts of reciprocal systems PbX + CdI2=CdX + PbI2 (X=S, Se, Te)

    International Nuclear Information System (INIS)

    Odin, I.N.; Chukichev, M.V.

    2001-01-01

    The transformations in the mutual PbX + CdI 2 =CdX + PbI 2 (X=S, Se, Te) systems leading to the crystallization of metastable polytypical modifications of lead iodide in metastable ternary compounds are studied for the first time. Microstructural and X-ray diffraction analyses were conducted. Their phase diagrams were constructed. The luminescence properties of the stable and metastable modifications of the lead iodide and the metastable compound Pb 4 SeI 6 were investigated. The lines 504 and 512 nm are noted in the 2H-PbI 2 cathodoluminescence spectra. The close lines - 508 and 516 nm provide for the 6R-PbI 2 modification. The metastable compound Pb 4 SeI 6 is characterized by the 769 and 868 nm lines [ru

  17. Anomalous metal concentrations in soil and till at the Ballinalack Zn-Pb deposit, Ireland

    Science.gov (United States)

    Kalveram, Ann-Kristin; McClenaghan, Seán H.; Kamber, Balz S.

    2017-04-01

    Metals such as zinc, iron, arsenic and lead are commonly found in low concentrations within soils. These signatures may occur as a result of natural dispersion from metal-bearing geological formations and (or) from anthropogenic sources. Prior to investigating any high or anomalous concentrations of metals in the surficial environment, it is important to reconcile potential sources of metals and verify whether element anomalies are in response to buried mineralization. Here we show how to distinguish true elevated concentrations from naturally occurring variations within a soil system. The research area is situated above the limestone-hosted Ballinalack Zn-Pb deposit in the central Irish Midlands. To investigate the pedogenesis and its related geochemical signature, top of the till and the BC soil horizon were sampled. Although the area can be described as pasture land, it does not preclude previous anthropogenic influences from former agricultural use and local small scale peat harvesting. For the soil BC horizon as well as in the top of the till, aqua regia-digestible element concentrations vary significantly and locally reach anomalous levels: Zn (median: 104 ppm; range: 27 - 13150 ppm), Pb (median: 16 ppm; range: 2 - 6430 ppm), As (median: 7.7 ppm; range: 1.4 - 362 ppm), Ag (median: 0.12 ppm; range: 0.04 - 19.9 ppm), Ba (median: 40 ppm; range: 10 - 1230 ppm), Cd (median: 1.5 ppm; range: 0.2 - 68 ppm), Co (median: 7.3 ppm; range: 0.5 - 22 ppm), Ni (median: 37 ppm; range: 3 - 134 ppm), Fe (median: 17900 ppm; range: 5000 - 52300 ppm), Ga (median: 2.4 ppm; range: 0.3 - 7.6 ppm), Sb (median: 1.2 ppm; range: 0.1 - 197 ppm) and Tl (median: 0.3 ppm; range: 0.02 - 8.6 ppm). Comparison with background levels from the area and grouped according to underlying geology, enrichment factor calculations (against Nb and Zr) indicate an elemental response to metalliferous-bearing bedrock. These results confirm that soil anomalies of Zn, Pb, As, Ag, Ba, Cd, Ni, Sb and Tl, are

  18. n-(CdMgTe/CdTe)/(p-(CdTe/ZnCdTe/ZnTe)/p-GaAs heterostructure diode for photosensor applications

    Science.gov (United States)

    Yahia, I. S.; AlFaify, S.; Abutalib, M. M.; Chusnutdinow, S.; Wojtowicz, T.; Karczewski, G.; Yakuphanoglu, F.; Al-Bassam, A.; El-Naggar, A. M.; El-Bashir, S. M.

    2016-05-01

    High quality n-(CdMgTe:I/n-CdTe:I)/(p-CdTe:N/p-ZnCdTe:N/p-ZnTe:N)/p-GaAs heterojunction diodes have been fabricated by molecular beam epitaxial growth. The illumination effect on the complex impedance and conductivity of heterostructure diode was investigated. The illumination intensities were taken up to the 200 mW/cm2 with frequency range of 42 Hz to 1 MHz. The observed real and imaginary parts of the complex impedance were strongly dependent on the illumination frequency. The inverse relation was observed between the illumination intensity and the complex impedance. The relaxation mechanism of the diode was analyzed by the Cole-Cole plots. The radius of the Cole-Cole curve decreases with increasing illumination intensity. This suggests a mechanism of illumination dependent on the relaxation process. It is also found that the conductivity increases linearly with increasing the illumination intensity. We can conclude that the new design heterostructure diode in our work is a good candidate in photodetector and optoelectronic applications.

  19. A proposal of “core enzyme” bioindicator in long-term Pb-Zn ore pollution areas based on topsoil property analysis

    International Nuclear Information System (INIS)

    Yang, JinShui; Yang, FengLong; Yang, Yang; Xing, GuanLan; Deng, ChunPing; Shen, YaTing; Luo, LiQiang; Li, BaoZhen; Yuan, HongLi

    2016-01-01

    To study the effects of long-term mining activities on the agricultural soil quality of Mengnuo town in Yunnan province, China, the heavy metal and soil enzyme activities of soil samples from 47 sites were examined. The results showed that long-term mining processes led to point source heavy metal pollution and Pb, Cd, Zn and As were the primary metal pollutants. Polyphenoloxidase was found the most sensitive soil enzyme activity and significantly correlated with almost all the metals (P < 0.05). Amylase (for C cycling), acid phosphatase (for P cycling) and catalase (for redox reaction) activities showed significantly positive correlations (P < 0.05) with Pb, Cd, Zn and As contents. The correlations between soil enzymes activities and Cd, Pb and Zn contents were verified in microcosm experiments, it was found that catalase activity had significant correlations (P < 0.05) with these three metals in short-term experiments using different soils under different conditions. Based on both field investigation and microcosm simulation analysis, oxidoreductases activities (rather than a specific enzyme activity) were suggested to be used as “core enzyme”, which could simply and universally indicate the heavy metal pollution degrees of different environments. And hydrolases (for C, N, P and S recycling) could be used as a supplement to improve correlation accuracy for heavy metal indication in various polluted environments. - Highlights: • Long-term Pb-Zn ore mining led to a point source heavy metal pollution. • Pb, Cd, Zn and As were the primary pollution metals in this region. • Polyphenoloxidase was found to be a good mining contamination bioindicator. • Oxidoreductase was proposed as enzyme indicators for soil heavy metal pollution. - Oxidoreductases could be used as a better and more sensitive bioindicator for soil heavy metal pollution than hydrolases.

  20. The Influence of Pb and Zn Contaminated soil on the Germination ...

    African Journals Online (AJOL)

    ADOWIE PERE

    www.bioline.org.br/ja. The Influence of Pb and Zn Contaminated soil on the Germination and Growth of ... of the periodic table such as aluminium, cadmium, zinc, chromium, copper ..... Remediation Division Robert S. Kerr. Environmental ...

  1. Investigation of effect of Ag(1), Cd(2) and Zn(2) on chemical nickel plating

    International Nuclear Information System (INIS)

    Lunyatskas, A.M.; Tarozajte, R.K.; Gyanutene, I.K.; Lyaukonis, Yu.Yu.

    1978-01-01

    Investigated is the effect of Ag(1), Cd(2) and Zn(2) on chemical nickel plating using hypophosphite aimed to get corresponding alloys from alkali solutions. The H 2 formed volume and potential of coating have been measured while nickel plating. It is possible to have plating of Ni-P-Ag, Ni-P-Zn, Ni-P-Cd, Ni-P-Zn-Cd content coatings in alkali solutions using hypophosphite Ni-P-Zh and Ni-P-Zn-Cd coatings have corrosion resistance and unporousness. Cd and Zn inclusion in Ni-P coating is supposed to have both chemical and electrochemical origin

  2. 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.

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

    African Journals Online (AJOL)

    hope&shola

    electrostatic precipitators, bag-filters are generally used in incinerator ... often used to prepare various ceramic products like bricks and tiles ... ceramics. The chloride salts of Cd and Pb are considered because chloride is one of the major anionic constituents of MSWI fly ash. Finally the leaching behaviours of Pb and Cd ...

  4. High performance p-i-n CdTe and CdZnTe detectors

    CERN Document Server

    Khusainov, A K; Ilves, A G; Morozov, V F; Pustovoit, A K; Arlt, R D

    1999-01-01

    A breakthrough in the performance of p-i-n CdTe and CdZnTe detectors is reported. The detector stability has been significantly improved, allowing their use in precise gamma and XRF applications. Detectors with energy resolution close to Si and Ge were produced operating with only -30--35 deg. C cooling (by a Peltier cooler of 15x15x10 mm size and a consumed power less than 5 W). Presently detectors with volume of up to 300 mm sup 3 are available. In terms of photoelectric effect efficiency it corresponds to HPGe detectors with volumes of about 1.5 cm sup 3. The possibilities of further improvement of CdTe and CdZnTe detector characteristics are discussed in this paper.

  5. Tolerance of Portulaca grandiflora to individual and combined application of Ni, Pb and Zn.

    Science.gov (United States)

    Mihailovic, N; Andrejić, G; Dželetović, Ž

    2015-01-01

    In the present study, metal accumulation capacity and tolerance of Portulaca grandiflora were investigated. Plants were grown under greenhouse conditions in pots on soil amended with Ni, Pb and Zn to the final concentration of 2 mmol kg(-1) for each metal. Results show considerable accumulating capacity and translocation of Ni and Zn, as well as significant accumulation of Pb in roots. A slight decrease of biomass with Zn and of chlorophyll content with Zn and Ni were observed, as well as an increase of proline content with each of the metals. Combinations of metals revealed mutual interference affecting both the uptake and translocation of the metals and their impact on physiological parameters. Results suggest that Portulaca grandiflora, although not a hyperaccumulator, shows a good tolerance and accumulation capacity for Ni, Pb and Zn, but, for the purposes of remediation, interference of the metals must be taken into account.

  6. Flux flow and proximity effects in aligned Pb--Cd eutectic lamellar structures

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, C. R.

    1977-09-01

    A high speed directional solidification technique was used to fabricate lamellar Pb-Cd and (Pb-Mg)--(Cd-Mg) superconductor-normal metal composites in which all the lamellae are oriented perpendicular to the broad surface of the sample. These lamellar composites are found to behave like a large number (approximately 1000) of superconducting-normal-superconducting junctions. For the Pb-Cd eutectic system, the critical current densities and critical fields have shown no dependence upon the lamellar periods between 1.0 and 3.1 microns. The critical current density of the aligned lamellar Pb-Cd structures was enhanced approximately 50% when compared to quenched eutectic alloy and to pure Pb. The superconducting transition temperature, T/sub c/, varies inversely with the square of the thickness of the superconducting material as expected from Ginzburg-Landau theory. Upon annealing, the Pb lamellae change from type II to type I superconductivity.

  7. Flux flow and proximity effects in aligned Pb--Cd eutectic lamellar structures

    International Nuclear Information System (INIS)

    Spencer, C.R.

    1977-09-01

    A high speed directional solidification technique was used to fabricate lamellar Pb-Cd and (Pb-Mg)--(Cd-Mg) superconductor-normal metal composites in which all the lamellae are oriented perpendicular to the broad surface of the sample. These lamellar composites are found to behave like a large number (approximately 1000) of superconducting-normal-superconducting junctions. For the Pb-Cd eutectic system, the critical current densities and critical fields have shown no dependence upon the lamellar periods between 1.0 and 3.1 microns. The critical current density of the aligned lamellar Pb-Cd structures was enhanced approximately 50% when compared to quenched eutectic alloy and to pure Pb. The superconducting transition temperature, T/sub c/, varies inversely with the square of the thickness of the superconducting material as expected from Ginzburg-Landau theory. Upon annealing, the Pb lamellae change from type II to type I superconductivity

  8. 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.

  9. 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.)

  10. Fate of Heavy Metals Pb and Zn in the West Season at Jeneberang Estuary, Makassar

    Directory of Open Access Journals (Sweden)

    Najamuddin .

    2017-08-01

    Full Text Available The pollutant quantity of heavy metals entering water environment does not give complete answer toward the generated effect and risk, however it needs thoroughly study related to the pollutant dynamic. The aim of this research was to investigate the fate of Pb and Zn in water, such as: distribution, behavior, and reactivity (case study: Jeneberang Estuary, Makassar. Pb and Zn concentrations were determined using Atomic Absorption Spectrophotometry (AAS. The distribution of dissolved Pb and Zn showed a pattern that the lowest concentration was in the fresh water (the river zone, whereas the highest concentration was in the salt water (the marine zone. The distribution pattern of particulate Pb and Zn showed that the highest concentration was in the fresh water (the river zone and the salt water (the marine zone, whereas the lowest concentration was in the estuary zone. The behavior of dissolved Pb and Zn tended to increase the concentration (desorption along the increased salinity gradient. The residual fraction was the dominant component of geochemical fractions in the sediment that indicated the sources of Pb and Zn mainly derived from a natural process and the reactivity was low in the water.   Keywords: distribution, behavior, reactivity, lead, zinc, pollution

  11. New developments in clinical applications of CdTe and CdZnTe detectors

    International Nuclear Information System (INIS)

    Scheiber, C.

    1996-01-01

    This review about the medical applications of CdTe and CdZnTe is an update on the 1992 paper (1992). This new paper is legitimized by the recent progress which has been made in this field. First of all, the usefulness of a new material, i.e. CdZnTe, has been demonstrated. While the two materials are still being improved, it seems as yet too early to debate which of CdTe:Cl or CdZnTe will be the best choice. Historical applications span over the past 18 years, involving devices like miniature probes for per-operative scintigraphy or the monitoring of physiological functions and, closer to us, appliances dedicated to bone densitometry, and have been expanding as such devices have become commercially available, for many years now. Newly available microelectronic circuitry allows 2D-arrays to be built for digital quantitative X-ray (chest, dental..) and for high-resolution gamma cameras. The clinical demand is very high, especially in the field of nuclear medicine. Although there already exist clinical demonstrators, the future of such CdTe applications depends on further reduction in material and device mounting costs. New perspectives concern XCT applications, but the data resulting from research work are kept for restricted use within industrial R and D laboratories. (orig.)

  12. Performance of prototype segmented CdZnTe arrays

    International Nuclear Information System (INIS)

    Parsons, A.; Palmer, D.M.; Kurczynski, P.; Barbier, L.; Barthelmy, S.; Bartlett, L.; Gehrels, N.; Krizmanic, J.; Stahle, C.M.; Tueller, J.; Teegarden, B.

    1998-01-01

    The Burst and All Sky Imaging Survey (BASIS) is a proposed mission to provide ∼3 arc second locations of approximately 90 Gamma-Ray Bursts (GRBs) per year. The BASIS coded aperture imaging system requires a segmented detector plane able to detect the interaction position of (10--150 keV) photons to less than 100 microm. To develop prototype detector arrays with such fine position resolution the authors have fabricated many 15 mm x 15 mm x 2 mm 100 microm pitch CdZnTe strip detectors. They have assembled these fine pitch CdZnTe strip detectors into prototype 2 x 2 and 6 x 6 element arrays read out by ASIC electronics. The assembly and electronics readout of the 6 x 6 flight prototype array will be discussed, and preliminary data illustrating the uniformity and efficiency of the array will be presented

  13. RNAA determination of As, Cd and Zn in biological materials

    International Nuclear Information System (INIS)

    Taskaev, E.; Penev, I.; Kinova, L.

    1985-01-01

    In connection with the IAEA project 3739/RB the elements Hg, As, Cd and Zn in human spleen, kidney, heart, liver, SRM Bovine Liver 1577a and Bowen's Kale. The consecutive extraction have been chosen as the most rational approach determining these elements in a single specimen. Aiming at getting reliable results well established systems were used (ditizone to separate Hg, Cu and DEDTC to extract As, Cd and Zn). Special attention was paid to the accuracy of the determination. Monitoring, optimization and cooling time and control of chemical yield were carried out in each case. The samples were irradiated in the vertical channel of the IRT-2000 reactor in Sofia, in thermal neutron flux of about 5.10 12 n.cm -2 .s -1 for 24 h. Iron monitor was used and cooling time varied from 20 h to 30 h

  14. Isostructural and heterostructural MgZnO and CdZnO alloys

    Energy Technology Data Exchange (ETDEWEB)

    Schleife, Andre; Roedl, Claudia; Bechstedt, Friedhelm [Institut fuer Festkoerpertheorie und -optik and European Theoretical Spectroscopy Facility, Friedrich-Schiller-Universitaet Jena, 07743 Jena (Germany)

    2011-07-01

    One important goal of materials design is to purposefully tailor the fundamental band gap. Recently, group-II oxides such as MgO, ZnO, and CdO are discussed to possibly supersede the nitrides for certain applications, e.g. in optoelectronics. Since the band gaps of the oxides cover a large spectral range from 1.8 eV (CdO) up to 7.7 eV (MgO), their alloys seem to be promising - unless the different equilibrium crystal structures of the end components (rocksalt-MgO and -CdO vs. wurtzite-ZnO) prevent their application. By employing three different cluster statistics within a cluster-expansion approach we investigate the impact of different growth conditions on the composition of isostructural and heterostructural Mg{sub x}Zn{sub 1-x}O and Cd{sub x}Zn{sub 1-x}O alloys. Our total-energy calculations are based on density-functional theory using a generalized-gradient approximation for exchange and correlation. We also compute quasiparticle energies using the HSE03+G{sub 0}W{sub 0} approach. This allows us to derive the bowings of fundamental band gaps, which reveal a strongly nonlinear behavior. Using the solution of the Bethe-Salpeter equation for the optical polarization function we investigate the influence of the preparation conditions on the peaks related to bound excitonic states at the absorption edge.

  15. Low-temperature solid-state synthesis and optical properties of CdS-ZnS and ZnS-CdS alloy nanoparticles

    International Nuclear Information System (INIS)

    Liu Jinsong; Zhao Chuanbao; Li Ziquan; Chen Jiankang; Zhou Hengzhi; Gu Shanqun; Zeng Youhong; Li Yongchan; Huang Yongbing

    2011-01-01

    Highlights: → Using a simple low-temperature solid-state synthetic method, ZnS-CdS and CdS-ZnS alloy nanoparticles were obtained, respectively. → The size of the nanoparticles increased with increasing reaction temperature, and reaction sequence had no effect on the size of the nanoparticles under the same temperature. → The particle diameters of the CdS-ZnS products decreased gradually with increasing Cd 2+ /Zn 2+ molar ratio, whereas those of the ZnS-CdS products increased gradually with increasing Zn 2+ /Cd 2+ molar ratio. → The study shows that sufficient grinding and crystalline water may be a key in forming the alloy nanoparticles. → Optical properties of the products depend on reaction temperature, reactant addition sequence, and reactant molar ratio. - Abstract: A simple low-temperature solid-state synthetic method was employed to obtain ZnS-CdS and CdS-ZnS alloy nanoparticles. The effects of reaction sequence, reactant molar ratios, and synthesis temperature on the products were investigated. The crystal structure and morphology of the products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and fourier transform infrared (FT-IR) spectroscopy. The results show that the products are alloy nanoparticles with a cubic phase structure. The formation mechanism of the alloy nanoparticles is briefly discussed. Sufficient grinding and crystalline water may be essential to form alloy nanoparticles. Ultraviolet-visible (UV-vis) spectra show that the edge absorptions of the CdS-ZnS and ZnS-CdS nanoparticles were located between those of ZnS and CdS bulks, and the absorbance at the peak maximum was practically dependent on reaction temperature, reaction sequence, and molar ratio. Extrinsic deep-level emission resulted in strong peaks in the photoluminescence (PL) spectra. The position and intensity of the emission peaks varied with the conditions during synthesis.

  16. Lead Isotopic Compositions of Selected Coals, Pb/Zn Ores and Fuels in China and the Application for Source Tracing.

    Science.gov (United States)

    Bi, Xiang-Yang; Li, Zhong-Gen; Wang, Shu-Xiao; Zhang, Lei; Xu, Rui; Liu, Jin-Ling; Yang, Hong-Mei; Guo, Ming-Zhi

    2017-11-21

    Lead (Pb) pollution emission from China is becoming a potential worldwide threat. Pb isotopic composition analysis is a useful tool to accurately trace the Pb sources of aerosols in atmosphere. In this study, a comprehensive data set of Pb isotopes for coals, Pb/Zn ores, and fuels from China was presented. The ratios of 206 Pb/ 207 Pb and 208 Pb/ 206 Pb in the coals were in the range of 1.114-1.383 and 1.791-2.317, similar to those from Europe, Oceania, and South Asia, but different from those from America (p fuels from in coals. Urban aerosols demonstrated similar Pb isotopic compositions to coals, Pb/Zn ores, and fuels in China. After removing the leaded gasoline, the Pb in aerosols is more radiogenic, supporting the heavy contribution of coal combustion to the atmospheric Pb pollution.

  17. Contamination of the soil along the river Zletovska by metals as by products of economic production of Pb-Zn

    OpenAIRE

    Boev, Blazo; Lepitkova, Sonja

    1996-01-01

    This paper shows the results constraining the degree of contamination of soil along the course of the River Zletovska by some mewls. These are by- products of economic production of lead-zinc ores which are common in this area. Contamination of soils by some metals, first of all by Pb, Zn, Cu, Cd, As, Fe, Al, Mn, Na, K is an important issue for the quality of the environment in which we live from several aspects: accumulation of waters under river alluvions; agricultural produ...

  18. Infrared Illuminated CdZnTe detectors with improved performance

    International Nuclear Information System (INIS)

    Ivanov, V.; Loutchanski, A.; Dorogov, P.; Khinoverov, S.

    2013-06-01

    It was found that IR illumination of a properly chosen wavelength and intensity can significantly improve spectrometric characteristics of CdZnTe quasi-hemispherical detectors [1]. Improving of the spectrometric characteristics is due to improvement of uniformity of charge collection by the detector volume. For operation at room temperature the optimal wavelength of IR illumination is about 940 nm, but for operation at lower temperature of -20 deg. C the optimal wavelengths of IR illumination is about 1050 nm. Infrared illumination can be performed using conventional low-power IR LEDs. Application of SMD LEDs allows produce miniature detection probes with IR illuminated CdZnTe detectors. We have fabricated and tested a variety of detection probes with CdZnTe quasi-hemispherical detectors from the smallest with volumes of 1-5 mm 3 to larger with volumes of 1.5 cm 3 and 4.0 cm 3 . The use of IR illumination significantly improves spectrometric characteristics of the probes operating at room temperature, especially probes with detectors of large volumes. The probe with the detector of 4 cm 3 without IR illumination had energy resolution of 24.2 keV at 662 keV and of 12.5 keV with IR illumination. (authors)

  19. ZnS-Passivated CdSe/CdS Co-sensitized Mesoporous Zn2SnO4 Based Solar Cells

    International Nuclear Information System (INIS)

    Kim, Kyungho; Park, Ji Eun; Park, Eun Su; Park, Yun Chang; Kim, Joosun; Im, Chan; Lee, Man-Jong

    2014-01-01

    Graphical abstract: - Highlights: • Mesoporous Zn 2 SnO 4 sensitized by CdSe/CdS QDs were synthesized via a two-step sequential process. • Assembled QDs were characterized by HRTEM and STEM mapping. • Efficiency increase in CdSe/CdS co-sensitized Zn 2 SnO 4 DSSCs is discussed. • The role of ZnS passivation layer is discussed by impedance spectroscopy. - Abstract: CdS and CdSe/CdS quantum dot (QD) sensitizers were assembled onto mesoporous ternary Zn 2 SnO 4 photoanodes using a two-step sequential process of successive ionic layer absorption and reaction (SILAR) and chemical bath deposition (CBD) for QD-cosensitized solar cell applications. The assembled CdS and CdSe QDs were observed using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), high-resolution TEM (HRTEM), and STEM/energy-dispersive X-ray spectroscopy (EDS) elemental mapping. CdSe/CdS cosensitized Zn 2 SnO 4 -based cells showed a higher absorption onset position, a stepwise band-edge level alignment, and, thereby, an improved power conversion efficiency (PCE) of 1.628% under one-sun conditions, which is the best result obtained using mesoporous Zn 2 SnO 4 reported to date. In addition, the effect of a ZnS passivation layer on the photovoltaic performance and aging behavior has been investigated. Electrochemical impedance spectroscopy (EIS) showed that the main role of the ZnS layer is to enhance the aging behavior of the CdSe/CdS/Zn 2 SnO 4 cells by improving the electron lifetime and charge recombination

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  1. Chemical bath deposited PbS thin films on ZnO nanowires for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Gertman, Ronen [Dept of Chemistry, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Osherov, Anna; Golan, Yuval [Dept of Materials Engineering, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Visoly-Fisher, Iris, E-mail: irisvf@bgu.ac.il [Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Be' er Sheva 84105 (Israel); Department of Solar Energy and Environmental Physics, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Sede Boqer Campus 84990 (Israel)

    2014-01-01

    Photovoltaic devices usually exploit mid-range band-gap semiconductors which absorb in the visible range of the solar spectrum. However, much energy is lost in the IR and near-IR range. We combined the advantages of small band-gap, bulk-like PbS deposited by facile, cheap and direct chemical bath deposition (CBD), with the good electronic properties of ZnO and the large surface area of nanowires, towards low cost photovoltaic devices utilizing IR and near-IR light. Surprisingly, CBD of PbS on ZnO, and particularly on ZnO nanowires, was not studied hitherto. Therefore, the mechanism of PbS growth by chemical bath deposition on ZnO nanowires was studied in details. A visible proof is shown for a growth mechanism starting from amorphous Pb(OH){sub 2} layer, that evolved into the ‘ion-by-ion’ growth mechanism. The growth mechanism and the resulting morphology at low temperatures were controlled by the thiourea concentration. The grain size affected the magnitude of the band-gap and was controlled by the deposition temperatures. Deposition above 40 °C resulted in bulk-like PbS with an optical band-gap of 0.4 eV. Methods were demonstrated for achieving complete PbS coverage of the complex ZnO NW architecture, a crucial requirement in optoelectronic devices to prevent shorts. Measurements of photocurrents under white and near-IR (784 nm) illumination showed that despite a 200 meV barrier for electron transfer at the PbS/ZnO interface, extraction of photo-electrons from PbS to the ZnO was feasible. The ability to harvest electrons from a narrow band-gap semiconductor deposited on a large surface-area electrode can advance the field towards high efficiency, low cost IR and near-IR sensors and third generation solar cells. - Highlights: • PbS was deposited on ZnO nanowires using chemical bath deposition. • At 50 °C the growth mechanism starts from an amorphous Pb(OH){sub 2} layer. • At 5 °C the growth mechanism of PbS can be controlled by thiourea concentrations

  2. Comprehensive Study of All-Solid-State Z-Scheme Photocatalytic Systems of ZnO/Pt/CdZnS

    KAUST Repository

    Isimjan, Tayirjan Taylor

    2017-08-22

    We have investigated a Z-scheme based on a ZnO/Pt/CdZnS photocatalyst, active in the presence of a complex medium composed of acetic acid and benzyl alcohol, the effects of which on the catalyst stability and performance are studied. Transmission electron microscopy images showed uniformly dispersed sub-nanometer Pt particles. Inductively coupled plasma and X-ray photoelectron spectroscopy analyses suggested that Pt is sandwiched between ZnO and CdZnS. An apparent quantum yield (AQY) of 34% was obtained over the [ZnO]4/1 wt %Pt/CdZnS system at 360 nm, 2.5-fold higher than that of 1%Pt/CdZnS (14%). Furthermore, an AQY of 16% was observed using [ZnO]4/1 wt %Pt/CdZnS, which was comparable to that of 1 wt %Pt/CdZnS (10%) at 460 nm. On the basis of these results, we proposed a charge transfer mechanism, which was confirmed through femtosecond transient absorption spectroscopy. Finally, we identified the two main factors that affected the stability of the catalyst, which were the sacrificial reagent and the acidic pH.

  3. Remediation of contaminated agricultural soils near a former Pb/Zn smelter in Austria: Batch, pot and field experiments

    International Nuclear Information System (INIS)

    Friesl, W.; Friedl, J.; Platzer, K.; Horak, O.; Gerzabek, M.H.

    2006-01-01

    Metal contaminated crops from contaminated soils are possible hazards for the food chain. The aim of this study was to find practical and cost-effective measures to reduce metal uptake in crops grown on metal contaminated soils near a former metal smelter in Austria. Metal-inefficient cultivars of crop plants commonly grown in the area were investigated in combination with in-situ soil amendments. A laboratory batch experiment using 15 potential amendments was used to select 5 amendments to treat contaminated soil in a pot study using two Barley (Hordeum vulgare L.) cultivars that differed in their ability to accumulate cadmium. Results from this experiment identified 3 of these amendments for use in a field trial. In the pot experiment a reduction in ammonium nitrate extractable Cd (<41%) and Pb (<49%) compared to the controls was measured, with a concurrent reduction of uptake into barley grain (Cd < 62%, Pb < 68%). In the field extractable fractions of Cd, Pb, and Zn were reduced by up to 96%, 99%, and 99%, respectively in amended soils. - Gravel sludge and red mud, combined with metal-excluding cultivars, can improve contaminated land

  4. Thermal analysis and prediction of phase equilibria in ternary Pb-Zn-Ag system

    Directory of Open Access Journals (Sweden)

    Živković D.

    2011-01-01

    Full Text Available Ternary Pb-Zn-Ag system is typical for some physicochemical processes going on in refining phase in the extractive metallurgy of lead. Therefore, investigation of mentioned system is important from both theoretical and practical research of the phenomena occurring during the lead desilverizing process. The results of experimental investigation using differential thermal analysis (DTA and thermodynamic calculation of phase equilibria in Pb-Zn-Ag system according to CALPHAD method, in the sections with Zn:Ag mass ratio equal to 90:10, 70:30 and 50:50, are presented in this paper.

  5. Superplastic forming of the Cd-17.4Zn alloy; Conformado superplastico de la aleacion Cd-17.4Zn

    Energy Technology Data Exchange (ETDEWEB)

    Llanes-Briceno, J. A.; Torres-Villasenor, G. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2000-06-01

    In the present work the necessary steps to carry on the superplastic forming of the Cd-17.4Zn alloy are defined. The use of either atmospheric pressure or gas pressure as forming tools is analyzed. The optimum values of the variable involved (temperature, maximum strain and sensitivity index) are determined while a method for the characterization of futures superplastic alloys is set forth. The experimental characterization of the superplastic forming is achieved with free bulging of circular membranes of 12, 16, 24, 32 and 40 mm in diameter and with three different membrane thicknesses (0.4, 0.6, 0.8 mm). [Spanish] Se definen los pasos necesarios para el conformado superplastico de la aleacion Cd-17.4 Zn. Se comparan la presion atmosferica y el gas a presion como herramientas de conformado. Se determinan los valores optimos de la variables involucradas (temperatura, deformacion maxima e indice de sensibilidad) y se plantea una metodologia para la caracterizacion de futuras aleaciones superplasticas. El conformado superplastico se caracteriza experimentalmente mediante el inflado libre de membranas circulares de 12, 16, 24, 32 y 40 mm de diametro y tres diferentes espesores (0.4, 0.6 y 0.8 mm). Se muestra la estructura perlitica (enfuiada al aive Cd-17.4Zn) y la estructura grano fino. Se muestra la profundidad de deformacion en tres espesores (0.4, 0.6, 0.8 mm) a P=200 Kpa y T = 200 y a T = 230.

  6. Determination of toxicity limiting values of Zn, Cu, and Pb for oat and red clover

    Energy Technology Data Exchange (ETDEWEB)

    Hodenberg, A V; Finck, A

    1975-01-01

    Toxicity limiting values of Zn, Cu and Pb are determined in order to investigate the causes of growth damages in certain fields. Since the true toxicity limit is difficult to estimate, a somewhat higher content is called the toxicity limiting value resulting after the subtraction of a significant yield difference. The pot experiments with increasing fertilization of Zn, Cu and Pb in soil cultures gave the following results. For Zn, the toxicity limit is 410 ppm in oats at the beginning of tilling. In red clover six weeks of age, it is only 290 ppm of Zn and therefore much lower. For Cu, the toxicity limit is 20 ppm in oats at the beginning of tilling and 18 ppm in six weeks old red clover. For Pb, a toxic effect could be observed above 50 ppm, but this does not seem to be the true limit because of disturbing salt effects.

  7. A novel intermediate layer for Au/CdZnTe/FTO photoconductive structure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuelu; Wang, Linjun, E-mail: ljwang@shu.edu.cn; Xu, Run; Huang, Jian; Tao, Jun; Meng, Hua; Zhang, Jijun; Min, Jiahua

    2016-12-01

    Highlights: • Graphene layer was spin-coated on CdZnTe to form Au/graphene/CdZnTe/FTO structure. • Graphene layer can significantly improve the contact property of Au/CdZnTe. • Graphene layer can obviously enhance UV photo-response of CdZnTe. • Graphene is a potential buffer material for CdZnTe based high-energy detectors. - Abstract: In this work, graphene is tried to use to improve the performance of polycrystalline CdZnTe high-energy radiation and photon detectors. A graphene intermediate layer is prepared by spin-coating process on the surface of polycrystalline CdZnTe film, which forms a photoconductive Au/graphene/CdZnTe/FTO structure. XRD, Raman, photoelectric response and other characterisation methods are adopted to investigate the effect of graphene layer on the electrical characteristics and UV photo-response performance of CdZnTe photoconductive structure. It is demonstrated that graphene layer can significantly improve the contact property of Au/CdZnTe structure, and obviously enhance its UV photo-response and the UV sensitivity increased with one order of magnitude.

  8. Does Biochar Alter the Speciation of Cd and Pb in Aqueous Solution?

    Directory of Open Access Journals (Sweden)

    Liqiang Cui

    2014-11-01

    Full Text Available Cadmium and lead contamination in bodies of water has been a serious concern because of risk to the environment. A laboratory experiment was initiated to investigate the efficacy of biochar (BC in removing cadmium and lead (Cd and Pb, respectively from solution. After absorption by BC, the fractions of Cd and Pb at different solution temperatures were measured. The adsorption data were described by Langmuir isotherm with maximum adsorption capacities of 6.36, 6.47, and 6.74 mg Cd g-1 and 50.05, 55.86, and 63.09 mg Pb g-1 at 25, 35, and 45 °C, respectively. The adsorption capacities were affected by Cd/Pb initial concentration, pH, BC particle size, BC dosage, and reaction time. Biochar adsorbed the Cd and Pb mainly as species bound with carbonate (> 50% and organic compounds (~40%. Exchangeable and residual fractions of Cd and Pb were less than 10%. Results from this study indicate that BC is highly effective in the adsorption of the heavy metals Cd and Pb through binding with carbonates.

  9. CdCl{sub 2} treatment related diffusion phenomena in Cd{sub 1−x}Zn{sub x}S/CdTe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kartopu, G., E-mail: giray.kartopu@glyndwr.ac.uk; Clayton, A. J.; Barrioz, V.; Lamb, D. A.; Irvine, S. J. C. [Centre for Solar Energy Research (CSER), Glyndŵr University, OpTIC, St. Asaph Business Park, St. Asaph LL17 0JD (United Kingdom); Taylor, A. A. [Physics Department, Durham University, Durham DH1 3LE (United Kingdom)

    2014-03-14

    Utilisation of wide bandgap Cd{sub 1−x}Zn{sub x}S alloys as an alternative to the CdS window layer is an attractive route to enhance the performance of CdTe thin film solar cells. For successful implementation, however, it is vital to control the composition and properties of Cd{sub 1−x}Zn{sub x}S through device fabrication processes involving the relatively high-temperature CdTe deposition and CdCl{sub 2} activation steps. In this study, cross-sectional scanning transmission electron microscopy and depth profiling methods were employed to investigate chemical and structural changes in CdTe/Cd{sub 1−x}Zn{sub x}S/CdS superstrate device structures deposited on an ITO/boro-aluminosilicate substrate. Comparison of three devices in different states of completion—fully processed (CdCl{sub 2} activated), annealed only (without CdCl{sub 2} activation), and a control (without CdCl{sub 2} activation or anneal)—revealed cation diffusion phenomena within the window layer, their effects closely coupled to the CdCl{sub 2} treatment. As a result, the initial Cd{sub 1−x}Zn{sub x}S/CdS bilayer structure was observed to unify into a single Cd{sub 1−x}Zn{sub x}S layer with an increased Cd/Zn atomic ratio; these changes defining the properties and performance of the Cd{sub 1−x}Zn{sub x}S/CdTe device.

  10. High-level Zn and Cd tolerance in Silene paradoxa L. from a moderately Cd- and Zn-contaminated copper mine tailing

    International Nuclear Information System (INIS)

    Arnetoli, Miluscia; Vooijs, Riet; Gonnelli, Cristina; Gabbrielli, Roberto; Verkleij, Jos A.C.; Schat, Henk

    2008-01-01

    Cadmium and zinc tolerance were examined in populations of Silene paradoxa, one from uncontaminated calcareous soil (CVD) and one from a mine tailing (FC) (Cd < 1-15 ppm, Zn 400-1300 ppm, pH 2-6). The mine population exhibited extremely high Zn and Cd tolerance levels, although the degrees of Cd and Zn enrichment relatively low at the population site. Cd and Zn hypertolerance in FC were associated with reduced rates of accumulation of these metals, both in roots and shoots (Cd), or exclusively in shoots (Zn). However, exclusion potentially explained only a minor part of the superior tolerance in FC. Cd hypertolerance in FC was associated with decreased, rather than enhanced phytochelatin accumulation. The remarkably high levels of Cd and Zn hypertolerance in FC might relate to the low soil pH, due to oxidation of sulphide minerals, and the absence of soil organic matter at the FC site. - Silene paradoxa from a copper mine exhibits extreme levels of Zn and Cd tolerance

  11. Etch Pit Studies of II-VI-Wide Bandgap Semiconductor Materials ZnSe, ZnCdSe, and ZnCdMgSe Grown on InP

    National Research Council Canada - National Science Library

    Semendy, Fred

    1999-01-01

    Etch pit density (EPD) determination studies have been conducted on II-VI semiconductor materials ZnSe, ZnCdSe, and ZnCdMgSe grown on InP surfaces for the first time by using various etching solutions under different...

  12. Leakage current measurements on pixelated CdZnTe detectors

    International Nuclear Information System (INIS)

    Dirks, B.P.F.; Blondel, C.; Daly, F.; Gevin, O.; Limousin, O.; Lugiez, F.

    2006-01-01

    In the field of the R and D of a new generation hard X-ray cameras for space applications we focus on the use of pixelated CdTe or CdZnTe semiconductor detectors. They are covered with 64 (0.9x0.9 mm 2 ) or 256 (0.5x0.5 mm 2 ) pixels, surrounded by a guard ring and operate in the energy ranging from several keV to 1 MeV, at temperatures between -20 and +20 o C. A critical parameter in the characterisation of these detectors is the leakage current per pixel under polarisation (∼50-500 V/mm). In operation mode each pixel will be read-out by an integrated spectroscopy channel of the multi-channel IDeF-X ASIC currently developed in our lab. The design and functionality of the ASIC depends directly on the direction and value of the current. A dedicated and highly insulating electronics circuit is designed to automatically measure the current in each individual pixel, which is in the order of tens of pico-amperes. Leakage current maps of different CdZnTe detectors of 2 and 6 mm thick and at various temperatures are presented and discussed. Defect density diagnostics have been performed by calculation of the activation energy of the material

  13. Fast Neutron Detection Using Pixelated CdZnTe Spectrometers

    Science.gov (United States)

    Streicher, Michael; Goodman, David; Zhu, Yuefeng; Brown, Steven; Kiff, Scott; He, Zhong

    2017-07-01

    Fast neutrons are an important signature of special nuclear materials (SNMs). They have a low natural background rate and readily penetrate high atomic number materials that easily shield gamma-ray signatures. Therefore, they provide a complementary signal to gamma rays for detecting shielded SNM. Scattering kinematics dictate that a large nucleus (such as Cd or Te) will recoil with small kinetic energy after an elastic collision with a fast neutron. Charge carrier recombination and quenching further reduce the recorded energy deposited. Thus, the energy threshold of CdZnTe detectors must be very low in order to sense the small signals from these recoils. In this paper, the threshold was reduced to less than 5 keVee to demonstrate that the 5.9-keV X-ray line from 55Fe could be separated from electronic noise. Elastic scattering neutron interactions were observed as small energy depositions (less than 20 keVee) using digitally sampled pulse waveforms from pixelated CdZnTe detectors. Characteristic gamma-ray lines from inelastic neutron scattering were also observed.

  14. Synthesis of ZnO/CdSe hierarchical heterostructure with improved visible photocatalytic efficiency

    International Nuclear Information System (INIS)

    Wu, Yao; Xu, Fang; Guo, Defu; Gao, Zhiyong; Wu, Dapeng; Jiang, Kai

    2013-01-01

    ZnO/CdSe hierarchical heterostructure was prepared using pompon-like ZnO as substrate materials, and hexagonal CdSe nanoparticles were dispersed on the ZnO plates. The hybrid ZnO/CdSe samples were intensively investigated by XRD, SEM, TEM, HRTEM, PL and UV–vis absorption spectrum. The photocatalytic experiments confirm that ZnO/CdSe heterostructure exhibits improved photocatalytic efficiency compared to pure ZnO under visible light irradiation. CdSe nanoparticles are believed to serve as photosensitizers to extend the absorption spectrum to visible light region. In addition, the incorporation of CdSe can suppress the recombination of photogenerated electron-hole pairs, which contributes to the enhancement of photocatalytic efficiency.

  15. Divalent metal (Ca, Cd, Mn, Zn) uptake and interactions in the aquatic insect Hydropsyche sparna.

    Science.gov (United States)

    Poteat, Monica D; Díaz-Jaramillo, Mauricio; Buchwalter, David B

    2012-05-01

    Despite their ecological importance and prevalent use as ecological indicators, the trace element physiology of aquatic insects remains poorly studied. Understanding divalent metal transport processes at the water-insect interface is important because these metals may be essential (e.g. Ca), essential and potentially toxic (e.g. Zn) or non-essential and toxic (e.g. Cd). We measured accumulation kinetics of Zn and Cd across dissolved concentrations ranging 4 orders of magnitude and examined interactions with Ca and Mn in the caddisfly Hydropsyche sparna. Here, we provide evidence for at least two transport systems for both Zn and Cd, the first of which operates at concentrations below 0.8 μmol l(-1) (and is fully saturable for Zn). We observed no signs of saturation of a second lower affinity transport system at concentrations up to 8.9 μmol l(-1) Cd and 15.3 μmol l(-1) Zn. In competition studies at 0.6 μmol l(-1) Zn and Cd, the presence of Cd slowed Zn accumulation by 35% while Cd was unaffected by Zn. At extreme concentrations (listed above), Cd accumulation was unaffected by the presence of Zn whereas Zn accumulation rates were reduced by 58%. Increasing Ca from 31.1 μmol l(-1) to 1.35 mmol l(-1) resulted in only modest decreases in Cd and Zn uptake. Mn decreased adsorption of Cd and Zn to the integument but not internalization. The L-type Ca(2+) channel blockers verapamil and nifedipine and the plasma membrane Ca(2+)-ATPase inhibitor carboxyeosin had no influence on Ca, Cd or Zn accumulation rates, while Ruthenium Red, a Ca(2+)-ATPase inhibitor, significantly decreased the accumulation of all three in a concentration-dependent manner.

  16. Silver-bearing minerals in the Xinhua hydrothermal vein-type Pb-Zn deposit, South China

    Science.gov (United States)

    Wang, Minfang; Zhang, Xubo; Guo, Xiaonan; Pi, Daohui; Yang, Meijun

    2018-02-01

    Electron probe microanalysis (EPMA) results are reported for newly identified silver-bearing minerals from the Xinhua deposit, Yunkaidashan area, South China. The Xinhua deposit is a hydrothermal vein-type Pb-Zn deposit and is hosted in the Pubei Complex, which consists of a cordierite-biotite granite with a U-Pb zircon age of 244.3 ± 1.8-251.9 ± 2.2 Ma. The mineralization process is subdivided into four mineralization stages, characterized by the following mineral associations: mineralization stage I with quartz, pyrite, and sphalerite; mineralization stage II with siderite, galena, and tetrahedrite; mineralization stage III with quartz and galena; and mineralization stage IV with quartz, calcite, and baryte. Tetrahedrite series minerals, such as freibergite, argentotetrahedrite, and tennantite are the main Ag-bearing minerals in the Xinhua deposit. The greatest concentration of silver occurs in phases from mineralization stage II. Microscopic observations reveal close relationship between galena and tetrahedrite series minerals that mostly occur as irregular inclusions within galena. The negative correlation between Cu and Ag in the lattices of tetrahedrite series minerals suggests that Cu sites are occupied by Ag atoms. Zn substitution for Fe in argentotetrahedrite and Cd substitution for Pb in tetrahedrite are also observed. Micro-thermometric data reveal that both homogenization temperatures and calculated salinities of hydrothermal fluids decrease progressively from the early to the later mineralization stages. The metal ions, such as Ag+, Cu+, Pb2+, and Zn2+, are transported as chlorine complex ions in the early mineralization stage and as bisulfide complex ions in the late mineralization stage, caused by changes in oxygen fugacity, temperature, and pH of the hydrothermal fluids. Because of the varying solubility of different metal ions, Pb2+, Zn2+, and Cu2+ ions are initially precipitated as galena, sphalerite, and chalcopyrite, respectively. With

  17. Theoretical Determination of Optimal Material Parameters for ZnCdTe/ZnCdSe Quantum Dot Intermediate Band Solar Cells

    Science.gov (United States)

    Imperato, C. M.; Ranepura, G. A.; Deych, L. I.; Kuskovsky, I. L.

    2018-03-01

    Intermediate band solar cells (IBSCs) are designed to enhance the photovoltaic efficiency significantly over that of a single-junction solar cell as determined by the Shockley-Queisser limit. In this work we present calculations to determine parameters of type-II Zn1-xCdxTe/Zn1-yCdySe quantum dots (QDs) grown on the InP substrate suitable for IBSCs. The calculations are done via the self-consistent variational method, accounting for the disk form of the QDs, presence of the strained ZnSe interfacial layer, and under conditions of a strain-free device structure. We show that to achieve the required parameters relatively thick QDs are required. Barriers must contain Cd concentration in the range of 35-44%, while Cd concentration in QD can vary widely from 0% to 70%, depending on their thickness to achieve the intermediate band energies in the range of 0.50-0.73 eV. It is also shown that the results are weakly dependent on the barrier thickness.

  18. Piezoelectric effect in CdTe/CdMnTe and CdTe/CdZnTe quantum wells

    International Nuclear Information System (INIS)

    Andre, Regis

    1994-01-01

    Materials with zinc-blende type structure are piezoelectric: any strain along a polar axis generates an electrical polarisation. Strained quantum wells of cubic II-VI or III-V semiconductors, grown along [111] or [112] axis, exhibit a strong built-in piezo-electric field (100 kV/cm for 1% strains). Such structures are very promising for applications to optical modulation, but it is necessary to study first the physical properties of piezoelectric heterostructures before they can be used in optical devices. For this purpose, we have performed an optical study of strained CdTe/CdMnTe or CdTe/CdZnTe quantum wells coherently grown by molecular beam epitaxy on [111] or [112] oriented substrates. Effects of piezoelectric field on optical and electronic properties of quantum wells have been analyzed in terms of the envelop function model, taking into account the effects of biaxial strains for [hhk] growth axis. Moreover, we have proposed an original way of measuring piezoelectric field in strained quantum wells, and we have used this method to show that CdTe exhibits strong non-linearities for piezoelectric field versus strain. This effect has never been mentioned before. We have also performed measurements of the piezoelectric coefficient e14 under high hydrostatic pressure inducing strains up to 2%, which shows that part of the non-linear effect is a volume effect. We have also studied the effects of the piezoelectric field on excitons in quantum wells. The binding energy decreases slightly when the electric field increases, but the oscillator strength, for the fundamental transition, decreases dramatically with the overlap of the envelope wavefunctions of electrons and holes. We have performed a modelization of an exciton in a piezoelectric quantum well using two variational parameters. This model provides an accurate calculation of excitonic absorption. Our experimental and theoretical results are in very good agreement, without any fitting parameters, for a large

  19. Core-Shell Zn x Cd1- x Se/Zn y Cd1- y Se Quantum Dots for Nonvolatile Memory and Electroluminescent Device Applications

    Science.gov (United States)

    Al-Amoody, Fuad; Suarez, Ernesto; Rodriguez, Angel; Heller, E.; Huang, Wenli; Jain, F.

    2011-08-01

    This paper presents a floating quantum dot (QD) gate nonvolatile memory device using high-energy-gap Zn y Cd1- y Se-cladded Zn x Cd1- x Se quantum dots ( y > x) with tunneling layers comprising nearly lattice-matched semiconductors (e.g., ZnS/ZnMgS) on Si channels. Also presented is the fabrication of an electroluminescent (EL) device with embedded cladded ZnCdSe quantum dots. These ZnCdSe quantum dots were embedded between indium tin oxide (ITO) on glass and a top Schottky metal electrode deposited on a thin CsF barrier. These QDs, which were nucleated in a photo-assisted microwave plasma (PMP) metalorganic chemical vapor deposition (MOCVD) reactor, were grown between the source and drain regions on a p-type silicon substrate of the nonvolatile memory device. The composition of QD cladding, which relates to the value of y in Zn y Cd1- y Se, was engineered by the intensity of ultraviolet light, which controlled the incorporation of zinc in ZnCdSe. The QD quality is comparable to those deposited by other methods. Characteristics and modeling of the II-VI quantum dots as well as two diverse types of devices are presented in this paper.

  20. 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, M.D.

    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...

  1. Correction of diagnostic x-ray spectra measured with CdTe and CdZnTe detectors

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, M [Osaka Univ., Suita (Japan). Medical School; Kanamori, H; Toragaito, T; Taniguchi, A

    1996-07-01

    We modified the formula of stripping procedure presented by E. Di. Castor et al. We added the Compton scattering and separated K{sub {alpha}} radiation of Cd and Te (23 and 27keV, respectively). Using the new stripping procedure diagnostic x-ray spectra (object 4mm-Al) of tube voltage 50kV to 100kV for CdTe and CdZnTe detectors are corrected with comparison of those spectra for the Ge detector. The corrected spectra for CdTe and CdZnTe detectors coincide with those for Ge detector at lower tube voltage than 70kV. But the corrected spectra at higher tube voltage than 70kV do not coincide with those for Ge detector. The reason is incomplete correction for full energy peak efficiencies of real CdTe and CdZnTe detectors. (J.P.N.)

  2. Synthesis of CdO/ZnS heterojunction for photodegradation of organic dye molecules

    Energy Technology Data Exchange (ETDEWEB)

    Venkata Reddy, C.; Shim, Jaesool; Vattikuti, S.V.P. [YeungnamUniversity, School of Mechanical Engineering, Gyeongsan-si, Gyeongsangbuk-do (Korea, Republic of); Bandaru, Narendra [IIT Gandhi Nagar, Department of Material Science and Engineering, Ahmedabad (India)

    2017-06-15

    CdO, ZnS, and CdO/ZnS hybrid photocatalyst were prepared using a simple co-precipitation method, and its photocatalytical activity was studied. The materials were characterized using powder XRD, TEM, HRTEM, BET, Raman, optical absorption, FT-IR, Thermal analysis and PL. The XRD patterns confirmed the crystal structure of the prepared samples. The surface analysis shows that the CdO/ZnS hybrid photocatalyst have larger surface area than the CdO and ZnS. Optical analysis of the nanocomposites revealed that the bond energy decreased after adding ZnS nanoparticles due to interactions with CdO nanoparticles. Raman spectroscopy showed the phonon modes of the CdO and ZnS, and PL spectra showed the electronic interaction between them. The photo-induced electrons can be easily transferred from the CdO to the ZnS in the composite, which facilitates effective charge separation and enhances photocatalytic degradation. The highest photocatalytic activity was achieved using the CdO/ZnS hybrid photocatalyst, with which more than 92% degradation was achieved. The enhanced photocatalytic activity could be ascribed to the low recombination rate of the electron and hole pairs because of the interface action between the CdO and ZnS. (orig.)

  3. Content Heavy Metal Pb, Cd In Perna viridis And Sediments In Semarang Bay

    Science.gov (United States)

    Suprapto, D.; Suryanti, S.; Latifah, N.

    2018-02-01

    Waste disposal from human activities, generally contain heavy metals such as Pb and Cd which derived from industrial activities. The aims of the study were to know the concentration of Pb and Cd heavy metals contained in Perna viridis tissue, sediment and water at Semarang Bay. This study was conducted in May 2017 at Semarang Bay. - Samples were collected using purposive sampling method. The heavy metal content in the water and clam was observed using- APHA method and was analyzed using AAS (Atomic Absorption Spectrophotometer). The results showed that concentration of heavy metal of Pb in the water was 0.00-50.5mg/L and the Cd content was of 26.9-51.7 mg/L, whereas the concentration of Pb in the sediment is 445.5-2.053.0mg/L and Cd 963.3-2,150.0 mg/L. Pb content in soft tissue of Perna viridis - is 67.1-1.933.9 mg/L and the concentration of Cd was 203.5-5.787.3 mg/L. The analysis of Pb and Cd in seawater, sediment and soft tissue of Perna viridis according to Enviroment Ministerial decree (KepMenLH ) number 51 of 2004 and applied by NOAA 1999 does not exceed the quality standard, that meant that the Perna viridis has been contaminated by metal Pb it is controversial with the above sentence and Cd. It concluded that the metal content of Pb and Cd in Perna viridis tissue exceeds the quality standard, so it is not suitable to be consumed, especially in high quantity

  4. Metal speciation in agricultural soils adjacent to the Irankuh Pb-Zn mining area, central Iran

    Science.gov (United States)

    Mokhtari, Ahmad Reza; Roshani Rodsari, Parisa; Cohen, David R.; Emami, Adel; Dehghanzadeh Bafghi, Ali Akbar; Khodaian Ghegeni, Ziba

    2015-01-01

    Mining activities are a significant potential source of metal contamination of soils in surrounding areas, with particular concern for metals dispersed into agricultural area in forms that are bioavailable and which may affect human health. Soils in agricultural land adjacent to Pb-Zn mining operations in the southern part of the Irankuh Mountains contain elevated concentrations for a range of metals associated with the mineralization (including Pb, Zn and As). Total and partial geochemical extraction data from a suite of 137 soil samples is used to establish mineralogical controls on ore-related trace elements and help differentiate spatial patterns that can be related to the effects of mining on the agricultural land soils from general geological and environmental controls. Whereas the patterns for Pb, Zn and As are spatially related to the mining operations they display little correlation with the distribution of secondary Fe + Mn oxyhydroxides or carbonates, suggesting dispersion as dust and in forms with limited bioavailability.

  5. Synthesis and photocatalytic activity of three-dimensional ZnS/CdS composites

    International Nuclear Information System (INIS)

    Liu, Shuling; Li, Honglin; Yan, Lu

    2013-01-01

    Graphical abstract: - Highlights: • 3D urchin-like ZnS/CdS composites were synthesized via a two-step method. • The CdS nanoparticles were assembled on the thorns of 3D ZnS urchins. • The ZnS/CdS composites show excellent photocatalytic degradation activities. • The modification of CdS on ZnS is responsible for the enhanced property. - Abstract: Urchin-like ZnS/CdS semiconductor composites were successfully synthesized by combining solvothermal route with homogeneous precipitation process. The as-obtained samples were characterized by means of XRD, EDX, TEM, HR-TEM, ED and FE-SEM techniques. The results show that the as-obtained composites were comprised of the hexagonal structure ZnS and CdS, and CdS nanoparticles were assembled on the surfaces of the thorns of urchin-like ZnS. In addition, the optical properties and photocatalytic activities of the as-prepared ZnS/CdS composites toward some organic dyes (such as Methyl Orange, Pyronine B, Rhodamine B and Methylene Blue) were separately investigated. It is found that the ZnS/CdS composites exhibit excellent photocatalytic degradation activity for these dyes under UV irradiation, as compared to corresponding pure ZnS urchins and commercial anatase TiO 2 (P-25). This enhanced activity may be related to the modification of CdS nanoparticles on the surfaces of thorns of ZnS urchins and a tentative mechanism for the enhanced photocatalytic degradation activities of the ZnS/CdS composite catalyst was proposed

  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. ADVANCED READOUT ELECTRONICS FOR MULTIELEMENT CdZnTe SENSORS

    International Nuclear Information System (INIS)

    DE GERONIMO, G.; O CONNOR, P.; KANDASAMY, A.; GROSHOLZ, J.

    2002-01-01

    A generation of high performance front-end and read-out ASICs customized for highly segmented CdZnTe sensors is presented. The ASICs, developed in a multi-year effort at Brookhaven National Laboratory, are targeted to a wide range of applications including medical, safeguards/security, industrial, research, and spectroscopy. The front-end multichannel ASICs provide high accuracy low noise preamplification and filtering of signals, with versions for small and large area CdZnTe elements. They implement a high order unipolar or bipolar shaper, an innovative low noise continuous reset system with self-adapting capability to the wide range of detector leakage currents, a new system for stabilizing the output baseline and high output driving capability. The general-purpose versions include programmable gain and peaking time. The read-out multichannel ASICs provide fully data driven high accuracy amplitude and time measurements, multiplexing and time domain derandomization of the shaped pulses. They implement a fast arbitration scheme and an array of innovative two-phase offset-free rail-to-rail analog peak detectors for buffering and absorption of input rate fluctuations, thus greatly relaxing the rate requirement on the external ADC. Pulse amplitude, hit timing, pulse risetime, and channel address per processed pulse are available at the output in correspondence of an external readout request. Prototype chips have been fabricated in 0.5 and 0.35 (micro)m CMOS and tested. Design concepts and experimental results are discussed

  8. Purification of CdZnTe by electromigration

    International Nuclear Information System (INIS)

    Kim, K.; Kim, Sangsu; Hong, Jinki; Lee, Jinseo; Hong, Taekwon; Bolotnikov, A. E.; Camarda, G. S.; James, R. B.

    2015-01-01

    Electro-migration of ionized/electrically active impurities in CdZnTe (CZT) was successfully demonstrated at elevated temperature with an electric field of 20 V/mm. Copper, which exists in positively charged states, electro-migrated at a speed of 15 μm/h in an electric field of 20 V/mm. A notable variation in impurity concentration along the growth direction with the segregation tendency of the impurities was observed in an electro-migrated CZT boule. Notably, both Ga and Fe, which exist in positively charged states, exhibited the opposite distribution to that of their segregation tendency in Cd(Zn)Te. A CZT detector fabricated from the middle portion of the electro-migrated CZT boule showed an improved mobility-lifetime product of 0.91 × 10 −2  cm 2 /V, compared with that of 1.4 × 10 −3  cm 2 /V, observed in an as-grown (non-electro-migrated) CZT detector. The optimum radiation detector material would have minimum concentration of deep traps required for compensation

  9. Purification of CdZnTe by electromigration

    Science.gov (United States)

    Kim, K.; Kim, Sangsu; Hong, Jinki; Lee, Jinseo; Hong, Taekwon; Bolotnikov, A. E.; Camarda, G. S.; James, R. B.

    2015-04-01

    Electro-migration of ionized/electrically active impurities in CdZnTe (CZT) was successfully demonstrated at elevated temperature with an electric field of 20 V/mm. Copper, which exists in positively charged states, electro-migrated at a speed of 15 μm/h in an electric field of 20 V/mm. A notable variation in impurity concentration along the growth direction with the segregation tendency of the impurities was observed in an electro-migrated CZT boule. Notably, both Ga and Fe, which exist in positively charged states, exhibited the opposite distribution to that of their segregation tendency in Cd(Zn)Te. A CZT detector fabricated from the middle portion of the electro-migrated CZT boule showed an improved mobility-lifetime product of 0.91 × 10-2 cm2/V, compared with that of 1.4 × 10-3 cm2/V, observed in an as-grown (non-electro-migrated) CZT detector. The optimum radiation detector material would have minimum concentration of deep traps required for compensation.

  10. Possibilities for reusing the waste from the process of Zn-Pb ore beneficiation

    Directory of Open Access Journals (Sweden)

    Cichy Krystian

    2017-01-01

    Full Text Available This paper discusses the areas of storage, resources, and granulometric and chemical characteristics of old Zn-Pb tailings stored in heaps in the city of Bytom area. It presents the results of laboratory tests for development of the technological flowsheet for transformation of the material into Zn- Pb sulfide concentrates and the results of trials in an experimental system of the beneficiation flowsheet which was developed. In the further part of the paper, the results of the research work on preparation of the tailings with reduced metal content for further use are presented.

  11. Zn isotope study of atmospheric emissions and dry depositions within a 5 km radius of a Pb-Zn refinery

    Science.gov (United States)

    Mattielli, Nadine; Petit, Jérôme C. J.; Deboudt, Karine; Flament, Pascal; Perdrix, Esperanza; Taillez, Aurélien; Rimetz-Planchon, Juliette; Weis, Dominique

    The present paper examines the use of zinc isotopes as tracers of atmospheric sources and focuses on the potential fractionation of Zn isotopes through anthropogenic processes. In order to do so, Zn isotopic ratios are measured in enriched ores and airborne particles associated with pyrometallurgical activities of one of the major Pb-Zn refineries in France. Supporting the isotopic investigation, this paper also compares morphological and chemical characteristics of Zn particles collected on dry deposition plates ("environmental samples") placed within a 5 km radius of the smelter, with those of Zn particles collected inside the plant ("process samples"), i.e. dust collected from the main exhaust system of the plant. To ensure a constant isotopic "supply", the refinery processed a specific set of ores during the sampling campaigns, as agreed with the executive staff of the plant. Enriched ores and dust produced by the successive Zn extraction steps show strong isotope fractionation (from -0.66 to +0.22‰) mainly related to evaporation processes within the blast furnaces. Dust from the main chimney displays a δ 66Zn value of -0.67‰. Application of the Rayleigh equation to evaluate the fractionation factor associated with the Zn vapor produced after a free evaporation gives a range of αore/vapor from 1.0004 to 1.0008. The dry deposits, collected on plates downwind of the refinery, display δ 66Zn variations of up to +0.7‰. However, it is to be noted that between 190 and 1250 m from the main chimney of the refinery, the dry deposits show a high level of large (>10 μm) Zn, S, Fe and O bearing aggregates characterized by positive δ 66Zn values (+0.02 to +0.19‰). These airborne particles probably derive from the re-suspension of slag heaps and local emissions from the working-units. In contrast, from 1720 to 4560 m, the dry deposits are comprised of small (PM10) particles, including spherical Zn-bearing aggregates, showing negative δ 66Zn values (-0.52 to -0

  12. Comparative of Quercus spp. and Salix spp. for phytoremediation of Pb/Zn mine tailings.

    Science.gov (United States)

    Shi, Xiang; Wang, Shufeng; Sun, Haijing; Chen, Yitai; Wang, Dongxue; Pan, Hongwei; Zou, Yazhu; Liu, Jianfeng; Zheng, Linyu; Zhao, Xiulian; Jiang, Zeping

    2017-02-01

    A pot experiment was conducted to evaluate the feasibility of using tree seedlings for the phytoremediation of lead/zinc (Pb/Zn) mine tailings. Seedlings of three Quercus spp. (Q. shumardii, Q. phellos, and Q. virginiana) and rooted cuttings of two Salix spp. (S. matsudana and S. integra) were transplanted into pots containing 50 and 100 % Pb/Zn mine tailings to evaluate their tolerance of heavy metals. The five species showed different tolerance levels to the Pb/Zn tailings treatments. Q. virginiana was highly tolerant to heavy metals and grew normally in the Pb/Zn tailings. The root systems showed marked differences between the Quercus spp. and Salix spp., indicating that different mechanisms operated to confer tolerance of heavy metals. The maximum efficiency of photosystem II photochemistry value of the five species showed no differences among the treatments, except for Q. shumardii. All species showed low metal translocation factors (TFs). However, S. integra had significantly higher TF values for Zn (1.42-2.18) and cadmium (1.03-1.45) than did the other species. In this respect, Q. virginiana showed the highest tolerance and a low TF, implying that it is a candidate for phytostabilization of mine tailings in southern China. S. integra may be useful for phytoextraction of tailings in temperate regions.

  13. 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.

  14. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Cd(II) and Zn(II) thiocyanate coordination compounds with 3-ethylpyridine. Synthesis, crystal structures and properties

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Tristan; Jess, Inke; Dos Santos Cunha, Cesar; Terraschke, Huayna; Naether, Christian [Kiel Univ. (Germany). Inst. fuer Anorganische Chemie

    2018-04-01

    Reaction of Cd(NCS){sub 2} and Zn(NCS){sub 2} with 3-ethylpyridine leads to the formation of compounds of compositions M(NCS){sub 2}(3-ethylpyridine){sub 4} (M=Cd, 1-Cd; Zn, 1-Zn) and M(NCS){sub 2}(3-ethylpyridine){sub 2} (M=Cd, 2-Cd; Zn, 2-Zn). 1-Cd and 1-Zn are isotypic and form discrete complexes in which the metal cations are octahedrally coordinated by two trans-coordinating N-bonded thiocyanate anions and four 3-ethylpyridine co-ligands. In 2-Cd the cations are also octahedrally coordinated but linked into chains by pairs of μ-1,3-bridging anionic ligands. 2-Zn is built up of discrete complexes, in which the Zn cation is tetrahedrally coordinated by two N-bonded thiocyanate anions and two 3-ethylpyridine co-ligands. Compounds 1-Cd, 2-Cd and 2-Zn can be prepared in a pure state, whereas 1-Zn is unstable and transforms on storage into 2-Zn. If 1-Cd and 1-Zn are heated, a transformation into 2-Cd, respectively 2-Zn is observed. Luminescence measurements reveal that 1-Cd, 2-Cd and 2-Zn emit light in the blue spectral range with maxima at, respectively, 21724, 21654 and 22055 cm{sup -1}, assigned to ligand-based luminescence.

  16. Novel red-emission of ternary ZnCdSe semiconductor nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Shu-Ru, E-mail: srchung@nfu.edu.tw [National Formosa University, Graduate Institute of Materials Science and Green Energy Engineering (China); Wang, Kuan-Wen [National Central University, Institute of Materials Science and Engineering (China); Chen, Hong-Shuo; Chen, Hong-Hong [National Formosa University, Graduate Institute of Materials Science and Green Energy Engineering (China)

    2015-02-15

    The effect of chain lengths of fatty acids on the physical properties of CdSe and ZnCdSe semiconductor nanocrystals (NCs) synthesized by the colloidal chemistry procedure is investigated. The fatty acids, lauric acid (LA), and stearic acid (SA), with different lengths of carbon chains, are used to prepare CdSe and ZnCdSe NCs when hexyldecylamine (HDA) is applied as the sole surfactant. For CdSe–SA and ZnCdSe–SA, they have the same emission wavelength at 592 nm and the same particle size of 3.3 nm; however, their quantum yield (QY) is 75 and 16 %, respectively. In contrast, the emission wavelength of CdSe–LA and ZnCdSe–LA NCs is 609 and 615 nm, the particle size is about 3.5 and 4 nm under the same reaction time, and the QY of them are 33 and 59 %, respectively. The X-ray diffraction pattern shows that ZnCdSe NCs all have the wurtzite structure, and their main peaks are located between those of pure CdSe and ZnSe materials. The main phase of ZnCdSe–SA and ZnCdSe–LA is ZnSe and CdSe, respectively, implying that alloyed ZnCdSe NC can be prepared and ZnSe and CdSe phase can be promoted by SA and LA, respectively. Moreover, the QY of red-emission ZnCdSe–LA is higher than 50 %. These results suggest that the growth rate of CdSe as well as ZnCdSe NC can be enhanced by using LA as complex reagent and HDA as sole surfactant. It is expected that the reported effective synthetic strategy can be developed as a very practical, easy and not time-consuming approach to prepare red emissive NCs with high QY and high reproducibility.

  17. Novel red-emission of ternary ZnCdSe semiconductor nanocrystals

    International Nuclear Information System (INIS)

    Chung, Shu-Ru; Wang, Kuan-Wen; Chen, Hong-Shuo; Chen, Hong-Hong

    2015-01-01

    The effect of chain lengths of fatty acids on the physical properties of CdSe and ZnCdSe semiconductor nanocrystals (NCs) synthesized by the colloidal chemistry procedure is investigated. The fatty acids, lauric acid (LA), and stearic acid (SA), with different lengths of carbon chains, are used to prepare CdSe and ZnCdSe NCs when hexyldecylamine (HDA) is applied as the sole surfactant. For CdSe–SA and ZnCdSe–SA, they have the same emission wavelength at 592 nm and the same particle size of 3.3 nm; however, their quantum yield (QY) is 75 and 16 %, respectively. In contrast, the emission wavelength of CdSe–LA and ZnCdSe–LA NCs is 609 and 615 nm, the particle size is about 3.5 and 4 nm under the same reaction time, and the QY of them are 33 and 59 %, respectively. The X-ray diffraction pattern shows that ZnCdSe NCs all have the wurtzite structure, and their main peaks are located between those of pure CdSe and ZnSe materials. The main phase of ZnCdSe–SA and ZnCdSe–LA is ZnSe and CdSe, respectively, implying that alloyed ZnCdSe NC can be prepared and ZnSe and CdSe phase can be promoted by SA and LA, respectively. Moreover, the QY of red-emission ZnCdSe–LA is higher than 50 %. These results suggest that the growth rate of CdSe as well as ZnCdSe NC can be enhanced by using LA as complex reagent and HDA as sole surfactant. It is expected that the reported effective synthetic strategy can be developed as a very practical, easy and not time-consuming approach to prepare red emissive NCs with high QY and high reproducibility

  18. Characterization of Aerosols Containing Zn, Pb, and Cl from an Industrial Region of Mexico City

    International Nuclear Information System (INIS)

    Moffet, Ryan C.; Desyaterik, Yury; Hopkins, Rebecca J.; Tivanski, Alexei V.; Gilles, Marry K.; Wang, Yan A.; Shutthanandan, V.; Molina, Luisa T.; Abraham, Rodrigo G.; Johnson, Kirsten S.; Mugica, Violeta; Molina, Mario J.; Laskin, Alexander; Prather, Kimberly A.

    2008-01-01

    During the March, 2006 MILAGRO campaign, measurements in the Northern Mexico City Metropolitan Area revealed the frequent appearance of particles with a characteristically high content of internally mixed Zn, Pb, Cl, and P. A comprehensive study of the chemical and physical properties of these particles was performed using a complementary combination of aerosol measurement techniques. Individual particles were analyzed using Aerosol Time-of-Flight Mass Spectrometry (ATOFMS) and Computer Controlled Scanning Electron Microscopy/Energy Dispersive X-Ray spectroscopy (CCSEM/EDX). Proton Induced X-Ray Emission (PIXE) analysis of bulk aerosol samples provided time-resolved mass concentrations of individual elements. The PIXE measurements indicated that Zn is more strongly correlated with Cl than with any other element and that Zn concentrations are higher than other non-ferrous transition metals. The Zn- and Pb-containing particles have both spherical and non-spherical morphologies. Many metal rich particles had needle-like structures and were found to be composed of ZnO and/or Zn(NO3)2 6H2O as indicated by scanning transmission x-ray microscopy/near edge X-ray absorption spectroscopy (STXM/NEXAFS). The Zn and Pb rich particles were primarily in the submicron size range and internally mixed with elemental carbon. The unique chemical associations most closely match signatures acquired for garbage incineration. This unique combination of complementary analytical techniques has allowed for a comprehensive evaluation of Zn- and Pb- containing particles in a complex urban environment, highlighting unique characteristics that give powerful insight into their origin

  19. Interrelationships between Cd, Zn and birth weight in neonates of women who smoke

    International Nuclear Information System (INIS)

    Kuhnert, B.R.; Kuhnert, P.M.; Groh-Margo, S.; Webster, S.; Erhard, P.

    1986-01-01

    A study was designed to test the hypothesis that the increased cadmium level in pregnant women who smoke alters the metabolism of zinc in the maternal-fetal unit, and that this altered Zn metabolism may contribute to lower birth weight infants. One hundred-thirty mother/infant pairs were studied. Maternal whole blood and placental Cd were analyzed by graphite furnace atomic absorption spectrophotometry; maternal and fetal plasma, red blood cell and placental Zn by flame atomic absorption spectroscopy. Maternal plasma thiocyanate (SCN) levels were used as an index of smoking status. Zn intake was estimated by diet history in a subgroup of 34 patients. The data were analyzed using t-tests, correlation and stepwise multiple regression techniques. No differences in Zn intake were found between pregnant women who smoked and those who did not. The average daily intake of Zn was 10.2 +/- 5 mg; this is less than the RDA for Zn during pregnancy. The data show that there are significant positive correlations between SCN levels and levels of whole blood Cd, placental Cd, and placental Zn. Cord vein samples from infants of mothers who smoked had decreased red blood cell Zn. This was particularly true in nulliparous patients. In all patients, maternal whole blood Cd was found to be negatively related to birth weight and cord vein red blood cell Zn was positively related to birth weight. The results support the hypothesis of a Cd-Zn interaction in pregnant women who smoke. Additional findings suggest an effect of parity on the interaction between Cd and Zn. Placental Cd was found to be negatively related to birth weight in nulliparous patients (n=21). In multiparous patients (n=109) placental Zn was inversely related to birth weight. In patients with parity 2 or greater (n=54), placental Cd was directly predictive of placental Zn. These results may reflect a less favorable Zn nutritional status with increasing parity

  20. Vapour growth of Cd(Zn)Te columnar nanopixels into porous alumina

    International Nuclear Information System (INIS)

    Sochinskii, N.V.; Abellan, M.; Martin Gonzalez, M.; Saucedo, E.; Dieguez, E.; Briones, F.

    2006-01-01

    The vapour phase growth (VPG) of CdTe and Cd 1- x Zn x Te was performed in order to investigate the formation of Cd(Zn)Te columnar nanostructures, which could serve as a basis for micropixels usable for further development of X- and gamma-ray high-resolution imaging devices. The possibility to form the 'Cd(Zn)Te-in-porous alumina' nanostructures by VPG has been demonstrated. The Cd(Zn)Te crystals integrated into nanoporous alumina have shown to have photoluminescence properties compatible with those of the bulk crystals and planar epitaxial layers. Further investigations are going on to improve the structural quality of Cd(Zn)Te nanocrystals

  1. Coordination geometries of Zn(II) and Cd(II) in phosphotriesterase: Influence of water molecules in the active site

    DEFF Research Database (Denmark)

    Krauss, M; Olsen, Lars; Antony, J

    2002-01-01

    Models of the metal ion binding sites of native ZnZn and of cadmium-substituted ZnCd and CdCd phosphotriesterase, including full amino acid side chains, were geometry optimized with quantum mechanical methods, with effective fragment potentials (EFP) representing the protein environment surroundi...... to the Od1 of the carboxylate of the first-shell aspartate designated M 1, but the energy difference between Cd1Zn2 and the lowest energy Zn1Cd2 structure is only about 2 kcal/mol and decreasing with the addition of water molecules. The Zn1Cd2 arrangement is found experimentally....

  2. 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.

  3. Evidence for microbial activity in the formation of carbonate-hosted Zn-Pb deposits

    Science.gov (United States)

    Kucha, H.; Raith, J.

    2009-04-01

    *Kucha H **Raith J *University of Mining and Metallurgy, Faculty of Geology, Geophysics and Environmental Protection, Mickiewicza 30, PL-30-059 Krakow, Poland. ** University of Leoben, Department of Applied Geosciences and Geophysics, A-8700 Leoben, Peter Tunner Str. 5, Austria Evidence for microbial activity in the formation of carbonate-hosted Zn-Pb deposits To date evaluation of bacterial processes in the formation of carbonate-hosted Zn-Pb deposits is largely based on sulphur isotope evidence. However, during a past few years, textural criteria, have been established, which support the bacterial origin of many of these deposits. This has received a strong support from micro-, and nano-textures of naturally growing bacterial films in a flooded tunnel within carbonates that host the Piquette Zn-Pb deposit (Druschel et al., 2002). Bacterial textures, micro- and nano textures found in carbonate-hosted Zn-Pb deposits are: i)wavy bacterial films up to a few mm thick to up to a few cm long composed of peloids, ii)semimassive agglomeration of peloids in the carbonate matrix, and iii)solitary peloids dispersed in the carbonate matrix. Peloids are usually composed of a distinct 50-90um core most often made up of Zn-bearing calcite surrounded by 30-60um thick dentate rim composed of ZnS. Etching of Zn-carbonate cores reveals 1 - 2um ZnS filaments, and numerous 15 to 90nm large ZnS nano-spheres (Kucha et al., 2005). In massive ore composite Zn-calcite - sphalerite peloids are entirely replaced by zinc sulphide, and form peloids ghosts within banded sulphide layers. Bacterially derived micro- and nano-textures have been observed in the following carbonate-hosted Zn-Pb deposits: 1)Irish-type Zn-Pb deposits. In the Navan deposit the basic sulphur is isotopically light bacteriogenic S (Fallick at al., 2001). This is corroborated by semimassive agglomerations of composite peloids (Zn-calcite-ZnS corona or ZnS core-melnikovite corona). Etching of Zn-calcite core reveals globular

  4. The ‘sub’ metallide oxide hydrides Sr{sub 21}Si{sub 2}O{sub 5}H{sub 12+x} and Ba{sub 21}M{sub 2}O{sub 5}H{sub 12+x} (M = Zn, Cd, Hg, In, Tl, Si, Ge, Sn, Pb, As, Sb, Bi)

    Energy Technology Data Exchange (ETDEWEB)

    Jehle, Michael; Hoffmann, Anke [Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, D-79104 Freiburg (Germany); Kohlmann, Holger [Institut für Anorganische Chemie, Universität Leipzig, Johannisallee 29, D-04103 Leipzig (Germany); Scherer, Harald [Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, D-79104 Freiburg (Germany); Röhr, Caroline, E-mail: caroline@ruby.chemie.uni-freiburg.de [Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, D-79104 Freiburg (Germany)

    2015-02-25

    Highlights: • The sub metallide oxide hydrides (Sr/Ba){sub 21}M{sub 2}O{sub 5}H{sub 12+x} were prepared for 14 M elements. • M covers a wide range of elements, from the Zn group to the pentels. • The ionic partial structure contains isolated M anions and suboxide clusters [O{sub 5}A{sub 18}]. • The H-content was determined by neutron diffraction and {sup 1}H/{sup 2}D MAS-NMR spectroscopy. • Band structure calculations support the H/D content and distribution. - Abstract: The title compounds sporting a great variety of anions M of different formal charges have been synthesized from melts of the composition A:M:O:H/D = 21:2:5:24, using BaH{sub 2}/SrH{sub 2} as hydrogen sources. All phases were characterized by means of single crystal X-ray data [cubic, space group Fd3{sup ¯}m; Sr{sub 21}Si{sub 2}O{sub 5}H{sub 12+x}: a = 1911.90(1) pm, R1 = 0.0201; for the barium phases with Zn (a = 2041.7(3) pm, R1 = 0.077), Cd (a = 2063.3(1) pm, R1 = 0.051), Hg (a = 2050.7(1) pm, R1 = 0.059), In (a = 2060.7(1) pm, R1 = 0.101), Tl (a = 2068.1(10) pm, R1 = 0.0485), Si (a = 2033.6(1) pm, R1 = 0.045), Ge (a = 2035.6(1) pm, R1 = 0.037), Sn (a = 2053.2(2) pm, R1 = 0.054), Pb (a = 2059.7(1) pm, R1 = 0.056), As (a = 2023.0(3) pm, R1 = 0.087), Sb (a = 2041.9(1) pm, R1 = 0.067) and Bi (a = 2045.9(1) pm, R1 = 0.075)]. Neutron powder diffraction data collected for the Ba silicide (both H and D compound) were refined by the Rietveld method (a = 2037.0(1), R{sub p} = 0.0173; wR{sub p} = 0.0304, R(F{sup 2}) = 0.086). The statistically occupied (H/D)(1) site 96g, which corresponds to the carbon position inSr{sub 21}Si{sub 2}O{sub 5}C{sub 6}, together with two further sparsely occupied sites (H/D)(2,3), yields the overall composition Ba{sub 21}Si{sub 2}O{sub 5}D{sub 14}. The hydrogen content, its chemical character and the distribution among the three H/D positions was evaluated by {sup 1}H/{sup 2}H MAS NMR spectroscopy for the Si, Ge and Sb compound. The crystal structure exhibits two

  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. Distribution of toxic metals, Hg, Cd and Pb in zooplankton along the Indian coasts

    Digital Repository Service at National Institute of Oceanography (India)

    Sengupta, R.; Kureishy, T.W.

    Distribution of toxic metals such as Hg, Cd and Pb in zooplankton is assessed with a view to correlate it with the prevalent environmental conditions along the Indian coast. While Hg could not be detected in zooplankton the concentrations of Cd...

  7. 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.

    Dissolved labile and non-labile (organically associated) concentration of Cd, Pb and Cu in Mandovi Estuary, Goa, India have been measured for 1 y (February 1980 to January 1981). Percentage non-labile form varies from 0-50% of the total for Cd, from...

  8. Study on rice absorption and distribution of Cd in applying Zn fertilizer with 65Zn, 115Cdm tracing technique

    International Nuclear Information System (INIS)

    Tang Nianxin; Shen Jinxiong

    1994-01-01

    Results of study by using 65 Zn and 115 Cd m tracers show that, along with the increase of the amount of Cd in applying Zn fertilizer to soil, rice has the phenomena of growth retard and tiller delay in the earlier growing stage. The inhibiting phenomenon is lightened along with the progress of rice growth. Very small quantity of Cd might be helpful to the growth of rice. It would cause serious inhibition to rice growth when the amount of Cd reaches to a definite limitation (64 x 10 -6 ). The distribution of Cd in a rice plant follows the following order in content: root>stem and leaves>brown rice>ear stalk>rice shell. Cd is mainly accumulated in rice root, taking 90% of the total amount of Cd contained in whole rice plant. The amount of Cd absorbed by rice increases with the amount of Cd applied to soil, though the total absorption extremely low, for example, only about 0.1% of the applied amount could be absorbed by two crops of rice, most of the applied Cd still retains in soil. Less and less Zn could be absorbed and utilized by rice along with the increase of the amount of the applied Cd. Application of Mn fertilizer affects negatively the absorption of Cd by rice, especially in brown rice

  9. Biomonitoring potential of five sympatric Tillandsia species for evaluating urban metal pollution (Cd, Hg and Pb)

    Science.gov (United States)

    Sánchez-Chardi, Alejandro

    2016-04-01

    The present study quantifies non essential heavy metals highly toxic for biological systems (Pb, Hg and Cd) in five autochthonous epiphytic plants from Tillandsia genus (T. recurvata, T. meridionalis, T. duratii, T. tricholepis, T. loliacea) according to different traffic levels (reference, low, medium and high polluted sites) in Asunción (Paraguay). The three metals increased in polluted sites following Pb (till 62.99 ppm in T. tricholepis) > Cd (till 1.35 ppm in T. recurvata) > Hg (till 0.36 ppm in T. recurvata) and Pb and Cd levels were directly related to traffic flow. Although the species showed similar bioaccumulation pattern (namely, higher levels of metals in polluted sites), enrichment factors (maximum EF values 37.00, 18.16, and 11.90 for Pb, Hg, and Cd, respectively) reported T. tricholepis as the most relevant bioindicator due to its wide distribution and abundance in study sites, low metal content in control site and high metal contents in polluted sites, and significant correlations with traffic density of Pb and Cd. This study emphasizes the necessity of biomonitoring air pollution in areas out of air monitoring control such as Asunción, where the high levels of metal pollution especially Pb, may represent an increment of risk for the human population inhabiting this urban area.

  10. PbS/Cd3P2 quantum heterojunction colloidal quantum dot solar cells

    International Nuclear Information System (INIS)

    Cao, Hefeng; Xu, Songman; Liu, Huan; Liu, Zeke; Zhu, Xiangxiang; Peng, Jun; Ma, Wanli; Hu, Long; Luo, Miao; Tang, Jiang

    2015-01-01

    Here, we demonstrated the quantum heterojunction colloidal quantum dot (CQD) solar cells employing the PbS CQDs/Cd 3 P 2 CQDs architecture in which both the p-type PbS and n-type Cd 3 P 2 CQD layers are quantum-tunable and solution-processed light absorbers. We synthesized well-crystallized and nearly monodispersed tetragonal Cd 3 P 2 CQDs and then engineered their energy band alignment with the p-type PbS by tuning the dot size and hence the bandgap to achieve efficient light absorbing and charge separation. We further optimized the device through the Ag-doping strategy of PbS CQDs that may leverage an expanded depletion region in the n-layer, which greatly enhances the photocurrent. The resulting devices showed an efficiency of 1.5%. (paper)

  11. 210Pb geochronology and trace metal fluxes (Cd, Cu and Pb) in the Gulf of Tehuantepec, South Pacific of Mexico

    International Nuclear Information System (INIS)

    Ruiz-Fernandez, Ana Carolina; Paez-Osuna, Federico; Machain-Castillo, Maria Luisa; Arellano-Torres, Elsa

    2004-01-01

    Distributions of Al, Cd, Cu, Fe, Li, Mn and Pb were analyzed in a sediment core collected in the Gulf of Tehuantepec, an important fisheries region located in the South Pacific of Mexico, where data on metal accumulation and accretion rates were previously almost nonexistent. Depth profiles of metal concentrations were converted to time-based profiles by using a 210 Pb-derived vertical accretion rate, estimated to be 0.05 cm year -1 on the average. Sediments were dated up to 8 cm depth, corresponding to a layer of ca. 140 years old. The historical changes of metal accumulation along the sediment core have shown a moderate enrichment of Cd, Cu and Pb concentrations at present, of about threefold the corresponding background concentrations. Chronological trace metal records showed that metal fluxes have increased over the last 20 years, reaching the maximum values at present of 2.5, 22.5 and 45.8 (μg cm -2 year -1 ) for Cd, Pb and Cu, respectively. These increments in metal fluxes are likely influenced by the development of anthropogenic land-based activities since over this period of time oil production activities in the region have had a significant development

  12. Phase diagrams of ZnTe-HgTe-Te and ZnTe-CdTe-HgTe-Te systems

    International Nuclear Information System (INIS)

    Andrukhiv, A.M.; Litvak, A.M.; Mironov, K.E.

    1992-01-01

    ZnTe-HgTe-Te system liquidus surface is investigated and solid solution layers are produced in this system by the method of liquid-phase epitaxy (LPE). The theoretical analysis of experimental and theoretical data allows to calculate the diagram of ZnTe-CdTe-HgTe-Te system fusibility. A significant effect of elastic stresses of the epitaxial layer, grown on CdTe substrate, on the process of LPE of solid solutions is established

  13. CdS-Sensitized ZnO Nanorod Photoelectrodes: Photoelectrochemistry and Photoinduced Absorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Idriss Bedja

    2011-01-01

    Full Text Available Thin films of ZnO semiconductor nanorods (ZnO-nr of 6 μm length and thin ZnO nanoparticulate films (ZnO-np have been prepared and modified with Q-dots CdS for comparison study. PIA (photoinduced absorption spectroscopy, a multipurpose tool in the study of dye-sensitized solar cells, is used to study a quantum-dot-modified metal-oxide nanostrucutred electrode. Q-dot CdS-sensitized ZnO-nr (1D network sensitized photoelectrode has demonstrated best performances in both photoelectrical response (IPCE max = 92% and broadening response into far visible comparing to ZnO-np-based CdS solar cell. Preadsorbing ZnO-nr with ZnO-np does not bring further improvement. Time constant for electron injection into ZnO-nr conduction band was relatively fast decay of 6.5 ms, similar to TiO2-coated CdS, and proves at least a well pore filling of ZnO-nr film by ultrafine CdS particles. Unidirectional electron transfer mechanistic in ZnO-nr has played a major role in these performances.

  14. Performance updating of CdZnTe strip-drift detectors

    DEFF Research Database (Denmark)

    Shorohov, M.; Tsirkunova, I.; Loupilov, A.

    2007-01-01

    59.6 and 662 keV correspondingly. Recently, significant progress was done in CdZnTe crystals growth technology. In the present paper we present preliminary result of performance updating of CdZnTe strip-drift detectors based on crystal of 10 x 10 x 6 mm 3 produced by Yinnel Tech company. Results...

  15. Highest-order optical phonon-mediated relaxation in CdTe/ZnTe quantum dots

    International Nuclear Information System (INIS)

    Masumoto, Yasuaki; Nomura, Mitsuhiro; Okuno, Tsuyoshi; Terai, Yoshikazu; Kuroda, Shinji; Takita, K.

    2003-01-01

    The highest 19th-order longitudinal optical (LO) phonon-mediated relaxation was observed in photoluminescence excitation spectra of CdTe self-assembled quantum dots grown in ZnTe. Hot excitons photoexcited highly in the ZnTe barrier layer are relaxed into the wetting-layer state by emitting multiple LO phonons of the barrier layer successively. Below the wetting-layer state, the LO phonons involved in the relaxation are transformed to those of interfacial Zn x Cd 1-x Te surrounding CdTe quantum dots. The ZnTe-like and CdTe-like LO phonons of Zn x Cd 1-x Te and lastly acoustic phonons are emitted in the relaxation into the CdTe dots. The observed main relaxation is the fast relaxation directly into CdTe quantum dots and is not the relaxation through either the wetting-layer quantum well or the band bottom of the ZnTe barrier layer. This observation shows very efficient optical phonon-mediated relaxation of hot excitons excited highly in the ZnTe conduction band through not only the ZnTe extended state but also localized state in the CdTe quantum dots reflecting strong exciton-LO phonon interaction of telluride compounds

  16. Rapid adsorption of Pb, Cu and Cd from aqueous solutions by β-cyclodextrin polymers

    Science.gov (United States)

    He, Junyong; Li, Yulian; Wang, Chengming; Zhang, Kaisheng; Lin, Dongyue; Kong, Lingtao; Liu, Jinhuai

    2017-12-01

    Removing heavy metals from aqueous solutions has drawn more and more attentions these years because of their serious global health challenge to human society. To develop an adsorbent with low-cost and high-efficiency for removal of heavy metals (HMs), β-cyclodextrin (β-CD) polymers crosslinked with rigid aromatic groups were prepared and used for lead (Pb), copper (Cu) and cadmium (Cd) removal for the first time. The negatively charged β-CD polymers with large BET surface area were suitable to be used in HMs adsorption. The adsorption process completed in 5 min was well fit by Freundlich isotherm model and pseudo-second-order model. The intraparticle diffusion model was also appropriate to describe the adsorption of Pb, Cu and Cd on β-CD polymer. The maximum of adsorption capacities at 25 °C for Pb, Cu and Cd were 196.42, 164.43 and 136.43 mg/g when the initial concentration was 200 mg/L. The HMs adsorption process on the surface of β-CD polymer was an endothermic and spontaneous process. Both of the electrostatic interaction and distribution of Pb, Cu and Cd species influenced the adsorption process at different pH values. The order of removal efficiencies in multi-component adsorption for the three metal ions were Pb > Cu > Cd. The adsorption mechanisms were H+ ions on hydroxyl groups exchanged with heavy metal ions and electrostatic interactions. This study indicated that β-CD polymers could be developed into effective adsorbents for rapid removal of heavy metals.

  17. 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

  18. Comprehensive Study of All-Solid-State Z-Scheme Photocatalytic Systems of ZnO/Pt/CdZnS

    KAUST Repository

    Isimjan, Tayirjan Taylor; Maity, Partha; Llorca, Jordi; Ahmed, Toseef; Parida, Manas R.; Mohammed, Omar F.; Idriss, Hicham

    2017-01-01

    We have investigated a Z-scheme based on a ZnO/Pt/CdZnS photocatalyst, active in the presence of a complex medium composed of acetic acid and benzyl alcohol, the effects of which on the catalyst stability and performance are studied. Transmission

  19. [Effect of different organic fertilizers on bioavailability of soil Cd and Zn].

    Science.gov (United States)

    Xie, Yun-he; Ji, Xiong-hui; Wu, Jia-mei; Huang, Juan; Guan, Di; Zhu, Jian

    2015-03-01

    The active effect of soil Cd and Zn and their interaction was studied in typical paddy field in south China by monitoring the contents of Cd and Zn in soil and rice in rice fields applied with pig manure, chicken manure or rice straw for 4 years continuously. The results showed that applying pig manure, chicken manure or rice straw had no significant impact on the soil total Cd content, soil available Cd content and soil Cd activity, but tended to increase the soil total Cd content and increased the soil total Zn content, soil available Zn content and Zn activity significantly. Applications of pig manure, chicken manure and rice straw all reduced the Cd content of brown rice, in order of pig manure > chicken manure > rice straw. The Cd contents of brown rice, stem and leaf in the treatment applied with pig manure were lower than in the control by 37.5%, 44.0% and 36.4%, respectively; the Cd contents of brown rice, stem and leaf in the treatment applied with chicken manure were lower than in the control by 22.5%, 33.8%, and 22.7%, respectively; the Cd content of brown rice in the treatment applied with rice straw was lower than in the control by 7.5% but its contents in stem and leaf increased by 8.2% and 22.7% , respectively. The reduction in the brown rice Cd content was mainly due to the reduction of Cd enrichment from soil to brown rice after application of pig or chicken manure, but mainly due to the reduction of Cd transportation from stem to brown rice after straw application. Applications of pig manure, chicken manure and rice straw increased Zn contents in rice stem by 53.4%, 53.4% and 13.9%, respectively, but all had no significant effect on brown rice and leaf' s Zn contents. Zn and Cd had the significant antagonistic effects in the soil and rice stem. The increase of Zn content in soil and rice stem inhibited the adsorption and accumulation of Cd in the brown rice, stem and leaf significantly, and with the increase of the proportion of Zn/Cd, the

  20. Biosorption of Zinc (Zn) and lead (Pb) by metal resistant bacterial isolate from mining tail

    Energy Technology Data Exchange (ETDEWEB)

    Bautista Hernandez, D. A.; Carranza Alvarado, M.; Fernandez Linares, L.; Ramirez Landy, I.

    2009-07-01

    The use of microbial biomass in the removal of metals in solution, mainly of low concentrations (100 mg L{sup -}1), present advantages in relation to the physicochemical methods. The resistant microorganisms are potential bio sorbents. The objective of the present study was the isolation, starting from mining tail, of strains with capacity of metal bio sorption (Zn and Pb). (Author)

  1. Biosorption of Zinc (Zn) and lead (Pb) by metal resistant bacterial isolate from mining tail

    International Nuclear Information System (INIS)

    Bautista Hernandez, D. A.; Carranza Alvarado, M.; Fernandez Linares, L.; Ramirez Landy, I.

    2009-01-01

    The use of microbial biomass in the removal of metals in solution, mainly of low concentrations (100 mg L - 1), present advantages in relation to the physicochemical methods. The resistant microorganisms are potential bio sorbents. The objective of the present study was the isolation, starting from mining tail, of strains with capacity of metal bio sorption (Zn and Pb). (Author)

  2. Thermal analysis and prediction of phase equilibria in ternary Pb-Zn-Ag System

    Czech Academy of Sciences Publication Activity Database

    Živković, D.; Minić, D.; Manasijević, D.; Šesták, Jaroslav; Živković, Ž.

    2011-01-01

    Roč. 47, č. 1 (2011), 23-30 ISSN 1450-5339 Institutional research plan: CEZ:AV0Z10100521 Keywords : Pb-Zn-Ag system * thermal analysis * phase equilibrium Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.317, year: 2011

  3. The Influence of Pb and Zn Contaminated soil on the Germination ...

    African Journals Online (AJOL)

    Journal of Applied Sciences and Environmental Management ... The bambara nut seedlings were irrigated with various concentrations of Pb and Zn ... as well as the organic matter, pH and moisture content of the soil were also evaluated. ... down to humans through the food chain if animals eat such plants during grazing.

  4. Characteristic of total suspended particulate (TSP) containing Pb and Zn at solid waste landfill

    Science.gov (United States)

    Budihardjo, M. A.; Noveandra, K.; Samadikun, B. P.

    2018-05-01

    Activities conducted at municipal solid waste landfills (MSWLs) potentially cause air pollution. Heavy vehicles in MSWLs release various pollutants that can have negative impacts for humans. One noticeable pollutant at MSWLs is airborne total suspended particulate (TSP) which may contain heavy metals such as Pb and Zn and can cause disease when inhaled by humans. In this study, TSP from a landfill in Semarang, Indonesia was collected and characterized to quantify the concentration of Pb and Zn. Meteorological factors (i.e. temperature, humidity and wind velocity) and landfill activities were considered as factors affecting pollutant concentrations. TSP was sampled using dust samplers while the concentrations of heavy metals in TSP were analyzed using an Atomic Absorption Spectrophotometer (AAS). Pb concentration ranged from 0.84 to 1.78 µg/m3 while Zn concentration was from 7.87 to 8.76 µg/m3. The levels of Pb were below the threshold specified by the Indonesian Government. Meanwhile, the threshold for Zn has not yet been determined.

  5. Optical properties of thermally annealed CdZnSe/ZnSe quantum dots

    International Nuclear Information System (INIS)

    Margapoti, Emanuela

    2010-01-01

    To analyse the diffusion characteristics, photoluminescence (PL) spectroscopy has been carried out in extensive detail on single, as well as, ensembles of thermally annealed (TA) CdSe/ZnSe QDs. For a series of QD-ensembles, each annealed for t A = 30 s at temperatures from T A = 300-550 C, the change in the QD-composition has been calculated from the blue-shift of the exciton ground-state PL-emission, using a concentration function based on Fick's laws of diffusion. The diffusion length (L D ) and the activation energy (E A ) have been determined thereof. For the studied QDs, E A has been evaluated to be 2.2 eV. Additionally, TA results also in an enhancement of the PL-intensity and reduction of the full-width-at-half maximum (FWHM) of the spectra. This point towards an increased homogeneity of the QD-size and composition, and decrease in the concentration of defects around the QDs. For single CdSe/ZnSe QDs, TA has been varied from 100-240 C, in steps for 20 C, with t A kept fixed at 30 s. Finally, the evolution of the magneto-optic response with post-growth thermal annealing has been studied for both individual QDs and QD-ensembles. An external magnetic field, applied perpendicular to the plane of the QDs (Faraday configuration), results in Zeeman spin splitting of the ground exciton state. The emissions from the Zeeman-split states are left and right circularly polarized and from the degree of circular polarization (DCP), as well as, the spectral separation of the PL-peaks, the g-factor can be estimated. For CdSe/ZnSe QD-ensembles, the g-factor has been observed to change sign with TA. (orig.).

  6. Optical properties of thermally annealed CdZnSe/ZnSe quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Margapoti, Emanuela

    2010-07-01

    To analyse the diffusion characteristics, photoluminescence (PL) spectroscopy has been carried out in extensive detail on single, as well as, ensembles of thermally annealed (TA) CdSe/ZnSe QDs. For a series of QD-ensembles, each annealed for t{sub A} = 30 s at temperatures from T{sub A} = 300-550 C, the change in the QD-composition has been calculated from the blue-shift of the exciton ground-state PL-emission, using a concentration function based on Fick's laws of diffusion. The diffusion length (L{sub D}) and the activation energy (E{sub A}) have been determined thereof. For the studied QDs, E{sub A} has been evaluated to be 2.2 eV. Additionally, TA results also in an enhancement of the PL-intensity and reduction of the full-width-at-half maximum (FWHM) of the spectra. This point towards an increased homogeneity of the QD-size and composition, and decrease in the concentration of defects around the QDs. For single CdSe/ZnSe QDs, TA has been varied from 100-240 C, in steps for 20 C, with t{sub A} kept fixed at 30 s. Finally, the evolution of the magneto-optic response with post-growth thermal annealing has been studied for both individual QDs and QD-ensembles. An external magnetic field, applied perpendicular to the plane of the QDs (Faraday configuration), results in Zeeman spin splitting of the ground exciton state. The emissions from the Zeeman-split states are left and right circularly polarized and from the degree of circular polarization (DCP), as well as, the spectral separation of the PL-peaks, the g-factor can be estimated. For CdSe/ZnSe QD-ensembles, the g-factor has been observed to change sign with TA. (orig.).

  7. CdS/ZnS nanocomposites: from mechanochemical synthesis to cytotoxicity issues

    International Nuclear Information System (INIS)

    Baláž, Peter; Baláž, Matej; Dutková, Erika; Zorkovská, Anna; Kováč, Jaroslav; Hronec, Pavol; Kováč, Jaroslav; Čaplovičová, Mária; Mojžiš, Ján; Mojžišová, Gabriela; Eliyas, Alexander; Kostova, Nina G.

    2016-01-01

    CdS/ZnS nanocomposites have been prepared by a two-step solid-state mechanochemical synthesis. CdS has been prepared from cadmium acetate and sodium sulfide precursors in the first step. The obtained cubic CdS (hawleyite, JCPDS 00-010-0454) was then mixed in the second step with the cubic ZnS (sphalerite, JCPDS 00-005-0566) synthesized mechanochemically from the analogous precursors. The crystallite sizes of the new type CdS/ZnS nanocomposite, calculated based on the XRD data, were 3–4 nm for both phases. The synthesized nanoparticles have been further characterized by high-resolution transmission electron microscopy (HRTEM) and micro-photoluminescence (μPL) spectroscopy. The PL emission peaks in the PL spectra are attributed to the recombination of holes/electrons in the nanocomposites occurring in depth associated with Cd, Zn vacancies and S interstitials. Their photocatalytic activity was also measured. In the photocatalytic activity tests to decolorize Methyl Orange dye aqueous solution, the process is faster and its effectivity is higher when using CdS/ZnS nanocomposite, compared to single phase CdS. Very low cytotoxic activity (high viability) of the cancer cell lines (selected as models of living cells) has been evidenced for CdS/ZnS in comparison with CdS alone. This fact is in a close relationship with Cd(II) ions dissolution tested in a physiological solution. The concentration of cadmium dissolved from CdS/ZnS nanocomposites with variable Cd:Zn ratio was 2.5–5.0 μg.mL"−"1, whereas the concentration for pure CdS was much higher — 53 μg.ml"−"1. The presence of ZnS in the nanocrystalline composite strongly reduced the release of cadmium into the physiological solution, which simulated the environment in the human body. The obtained CdS/ZnS quantum dots can serve as labeling media and co-agents in future anti-cancer drugs, because of their potential in theranostic applications. - Highlights: • CdS/ZnS nanocomposites with crystallite size 3–4

  8. CdS/ZnS nanocomposites: from mechanochemical synthesis to cytotoxicity issues

    Energy Technology Data Exchange (ETDEWEB)

    Baláž, Peter; Baláž, Matej [Institute of Geotechnics, Slovak Academy of Sciences, 04001 Košice (Slovakia); Dutková, Erika, E-mail: dutkova@saske.sk [Institute of Geotechnics, Slovak Academy of Sciences, 04001 Košice (Slovakia); Zorkovská, Anna [Institute of Geotechnics, Slovak Academy of Sciences, 04001 Košice (Slovakia); Kováč, Jaroslav; Hronec, Pavol; Kováč, Jaroslav [Institute of Electronics and Photonics, Slovak University of Technology and International Laser Centre, 81219 Bratislava (Slovakia); Čaplovičová, Mária [STU Centre for Nanodiagnostics, Slovak University of Technology, Vazovova 5, 812 43 Bratislava (Slovakia); Mojžiš, Ján; Mojžišová, Gabriela [Faculty of Medicine, P. J. Šafárik University, 04011 Košice (Slovakia); Eliyas, Alexander; Kostova, Nina G. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2016-01-01

    CdS/ZnS nanocomposites have been prepared by a two-step solid-state mechanochemical synthesis. CdS has been prepared from cadmium acetate and sodium sulfide precursors in the first step. The obtained cubic CdS (hawleyite, JCPDS 00-010-0454) was then mixed in the second step with the cubic ZnS (sphalerite, JCPDS 00-005-0566) synthesized mechanochemically from the analogous precursors. The crystallite sizes of the new type CdS/ZnS nanocomposite, calculated based on the XRD data, were 3–4 nm for both phases. The synthesized nanoparticles have been further characterized by high-resolution transmission electron microscopy (HRTEM) and micro-photoluminescence (μPL) spectroscopy. The PL emission peaks in the PL spectra are attributed to the recombination of holes/electrons in the nanocomposites occurring in depth associated with Cd, Zn vacancies and S interstitials. Their photocatalytic activity was also measured. In the photocatalytic activity tests to decolorize Methyl Orange dye aqueous solution, the process is faster and its effectivity is higher when using CdS/ZnS nanocomposite, compared to single phase CdS. Very low cytotoxic activity (high viability) of the cancer cell lines (selected as models of living cells) has been evidenced for CdS/ZnS in comparison with CdS alone. This fact is in a close relationship with Cd(II) ions dissolution tested in a physiological solution. The concentration of cadmium dissolved from CdS/ZnS nanocomposites with variable Cd:Zn ratio was 2.5–5.0 μg.mL{sup −1}, whereas the concentration for pure CdS was much higher — 53 μg.ml{sup −1}. The presence of ZnS in the nanocrystalline composite strongly reduced the release of cadmium into the physiological solution, which simulated the environment in the human body. The obtained CdS/ZnS quantum dots can serve as labeling media and co-agents in future anti-cancer drugs, because of their potential in theranostic applications. - Highlights: • CdS/ZnS nanocomposites with crystallite

  9. Influence of Zn and Pb on Rhizopogon roseolus mycelium - energy dispersion spectroscopy and cytochemical investigation

    Directory of Open Access Journals (Sweden)

    Katarzyna Turnau

    2014-01-01

    Full Text Available Mycelium isolated from fruitbodies of Rhizopogon roseolus, collected from calamine wastes in Poland, was cultivated on agar media supplemented with Zn or Pb salts. The stimulation of exudate production by the aerial mycelium and the mycelium growing on the surface of the media, accompanied by the change of mycelium pigmentation, was found as a result of Zn application. The presence of Pb resulted mainly in the stimulation of crystalloid production on the surface of mycelium, in direct contact with the medium. Exudate droplets formed on the surface of mycelium cultivated on media with and without the Zn addition, were investigated by means of cytochemical tests (PATAg and Gomori-Swift reaction. In the control media most droplets gave a diffused, positive reaction to both tests. In media supplemented with Zn salts, besides the droplet-like material described in the control also another kind of exudate was observed. It was characterized by the collar showing apositive Gomori-Swift reaction, while the rest of the exudate had an oily appearance and gave a faint or no reaction to both tests. Comparative research by means of scanning electron microscopy accompanied by energy dispersion spectroscopy, was carried out showing the differences in exudate and in mycelia composition as a result of the Zn and Pb presence in the medium.

  10. Multichannel CdZnTe Gamma Ray Spectrometer

    International Nuclear Information System (INIS)

    Doty, F.P.; Lingren, C. L.; Apotovsky, B. A.; Brunsch, J.; Butler, J. F.; Collins, T.; Conwell, R.L.; Friesenhahn, S.; Gormley, J.; Pi, B.; Zhao, S.; Augustine, F.L.; Bennet, B. A.; Cross, E.; James, R. B.

    1998-01-01

    A 3 cm 3 multichannel gamma spectrometer for DOE applications is under development by Digirad Corporation. The device is based on a position sensitive detector packaged in a compact multi-chip module (MCM) with integrated readout circuitry. The modular, multichannel design will enable identification and quantitative analysis of radionuclides in extended sources, or sources containing low levels of activity. The MCM approach has the advantages that the modules are designed for imaging applications, and the sensitivity can be arbitrarily increased by increasing the number of pixels, i.e. adding modules to the instrument. For a high sensitivity probe, the outputs for each pixel can be corrected for gain and offset variations, and summed digitally. Single pixel results obtained with discrete low noise readout indicate energy resolution of 3 keV can be approached with currently available CdZnTe. The energy resolution demonstrated to date with MCMs for 511 keV gamma rays is 10 keV

  11. Prospects of Ternary Cd1-x Zn x S as an Electron Transport Layer and Associated Interface Defects in a Planar Lead Halide Perovskite Solar Cell via Numerical Simulation

    Science.gov (United States)

    Chowdhury, Towhid Hossain; Ferdaous, Mohammad Tanvirul; Wadi, Mohd. Aizat Abdul; Chelvanathan, Puvaneswaran; Amin, Nowshad; Islam, Ashraful; Kamaruddin, Nurhafiza; Zin, Muhammad Irsyamuddin M.; Ruslan, Mohd Hafidz; Sopian, Kamaruzzaman Bin; Akhtaruzzaman, Md.

    2018-03-01

    In this study we present a ternary alloy, Cd1-x Zn x S as an electron transport layer for a planar lead halide perovskite solar cell via numerical simulation with solar cell capacitance simulator (SCAPS) software. Performance dependence on molar composition variation in the Cd1-x Zn x S alloy was studied for the mixed perovskite CH3NH3PbI3-x Cl x absorber and spiro-OMeTAD hole transport material in a planar perovskite solar cell. Additionally, the defects on both Cd1-x Zn x S/CH3NH3PbI3-x Cl x and CH3NH3PbI3-x Cl x /spiro-OMeTAD interface were thoroughly investigated. Simultaneously, a thickness of 700 nm for CH3NH3PbI3-x Cl x absorber with 50-nm-thick Cd0.2Zn0.8S (x = 0.8) was optimized. Analysis of the numerical solutions via SCAPS provides a trend and pattern for Cd0.2Zn0.8S as an effective electron transport layer for planar perovskite solar cells with a yield efficiency up to 24.83%. The planar perovskite solar cell shows an open-circuit voltage of 1.224 V, short-circuit current density of 25.283 mA/cm2 and a fill factor of 80.22.

  12. Comparative adsorption of Pb2+ and Cd2+ by cow manure and its vermicompost

    International Nuclear Information System (INIS)

    Zhu, Weiqin; Du, Wenhui; Shen, Xuyang; Zhang, Hangjun; Ding, Ying

    2017-01-01

    Organic waste has great potential for use as an amendment to immobilize heavy metals in the environment. Therefore, this study investigates various properties of cow manure (CM) and its derived vermicompost (CV), including the pH, cationic exchangeable capacity (CEC), elemental composition and surface structure, to determine the potential of these waste products to remove Pb 2+ and Cd 2+ from solution. The results demonstrate that CV has a much higher pH, CEC and more irregular pores than CM and is enriched with minerals and ash content but has a lower C, H, O and N content. Adsorption isotherms studies shows that the adsorption of Pb 2+ and Cd 2+ onto either CM or CV follows a Langmuir model and presents maximum Pb 2+ and Cd 2+ adsorption capacities of 102.77 mg g −1 and 38.11 mg g −1 onto CM and 170.65 and 43.01 mg g −1 onto CV, respectively. Kinetic studies show that the adsorption of Pb 2+ onto CM and CV fits an Elovich model, whereas the adsorption of Cd 2+ onto CM and CV fits a pseudo-second-order model. Desorption studies indicate that CV is more effective than CM in removing Pb 2+ and Cd 2+ . FTIR analysis demonstrates that the adsorption of Pb 2+ and Cd 2+ onto CM mainly depends on existed aliphatic alcohol, aromatic acid as well as new produced carbonates, whereas that onto CV may be contributed by the existed aliphatic alcohol, aromatic acids as well as some carbonates and phosphates. Thus, vermicomposting disposal of cow manure with destination mineral addition may broaden the way of its recycle and environmental usage. - Graphical abstract: The existed aliphatic alcohol, aromatic acids and its only carbonates and phosphates may underlie much higher efficiency of vermicompost (CV) on Pb 2+ and Cd 2+ removal than cow manure (CM). - Highlights: • Less irregular pores in cow manure (CM) than its vermicompost (CV). • More Pb 2+ or Cd 2+ could be removed from solution by vermicompost (CV) than by cow manure (CM). • The existed aliphatic

  13. Proton irradiation induced defects in Cd and Zn doped InP

    International Nuclear Information System (INIS)

    Rybicki, G.C.; Williams, W.S.

    1993-01-01

    Proton irradiation induced defects in Zn and Cd doped InP have been studied by deep level transient spectroscopy, (DLTS). After 2 MeV proton irradiation the defects H4 and H5 were observed in lightly Zn doped InP, while the defects H3 and H5 were observed in more heavily Zn and Cd doped InP. The defect properties were not affected by the substitution of Cd for Zn, but the introduction rate of H5 was lower in Cd doped InP. The annealing rate of defects was also higher in Cd doped InP. The use of Cd doped InP may thus result in an InP solar cell with even greater radiation resistance

  14. Thallium transformation and partitioning during Pb-Zn smelting and environmental implications.

    Science.gov (United States)

    Liu, Juan; Wang, Jin; Chen, Yongheng; Xie, Xiaofan; Qi, Jianying; Lippold, Holger; Luo, Dinggui; Wang, Chunlin; Su, Longxiao; He, Lucheng; Wu, Qiwei

    2016-05-01

    Thallium (Tl) is a toxic and non-essential heavy metal. Raw Pb-Zn ores and solid smelting wastes from a large Pb-Zn smelting plant - a typical thallium (Tl) pollution source in South China, were investigated in terms of Tl distribution and fractionation. A modified IRMM (Institute for Reference Materials and Measurement, Europe) sequential extraction scheme was applied on the samples, in order to uncover the geochemical behavior and transformation of Tl during Pb-Zn smelting and to assess the potential environmental risk of Tl arising from this plant. Results showed that the Pb-Zn ore materials were relatively enriched with Tl (15.1-87.7 mg kg(-1)), while even higher accumulation existed in the electrostatic dust (3280-4050 mg kg(-1)) and acidic waste (13,300 mg kg(-1)). A comparison of Tl concentration and fraction distribution in different samples clearly demonstrated the significant role of the ore roasting in Tl transformation and mobilization, probably as a result of alteration/decomposition of related minerals followed by Tl release and subsequent deposition/co-precipitation on fine surface particles of the electrostatic dust and acidic waste. While only 10-30% of total Tl amounts was associated with the exchangeable/acid-extractable fraction of the Pb-Zn ore materials, up to 90% of total Tl was found in this fraction of the electrostatic dust and acidic waste. Taking into account the mobility and bioavailability of this fraction, these waste forms may pose significant environmental risk. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Bio-remediation of Pb and Cd polluted soils by switchgrass: A case study in India.

    Science.gov (United States)

    Arora, Kalpana; Sharma, Satyawati; Monti, Andrea

    2016-01-01

    In the present study bioremediation potential of a high biomass yielding grass, Panicum virgatum (switchgrass), along with plant associated microbes (AM fungi and Azospirillum), was tested against lead and cadmium in pot trials. A pot trial was set up in order to evaluate bioremediation efficiency of P. virgatum in association with PAMs (Plant Associated Microbes). Growth parameters and bioremediation potential of endomycorrhizal fungi (AMF) and Azospirillum against different concentrations of Pb and Cd were compared. AM fungi and Azospirillum increased the root length, branches, surface area, and root and shoot biomass. The soil pH was found towards neutral with AMF and Azospirillum inoculations. The bioconcentration factor (BCF) for Pb (12 mg kg(-1)) and Cd (10 mg kg(-1)) were found to be 0.25 and 0.23 respectively and translocation index (Ti) was 17.8 and 16.7 respectively (approx 45% higher than control). The lower values of BCF and Ti, even at highest concentration of Pb and Cd, revealed the capability of switchgrass of accumulating high concentration of Pb and Cd in the roots, while preventing the translocation of Pb and Cd to aerial biomass.

  16. 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

  17. Performance optimization of CdTe and CdZnTe detectors for γ-spectrometry

    International Nuclear Information System (INIS)

    Montemont, Guillaume

    2000-01-01

    This study deals with room-temperature gamma spectrometry with CdTe and CdZnTe semiconductor detectors. The aim was the improvement of energy resolution and detection efficiency. Some different phenomena have been investigated. Electronic noise knowledge has enabled us to optimize the design of filtering. Charge transport induces signal shape uncertainty and the processing circuit has been adapted in order to account for these variations. Study and simulation of electrical current induction process has permitted the development of a new Frisch-grid based detection structure. We have reached 3% energy resolutions at 122 keV without detection efficiency loss. Finally, the remaining limits of detector performances have been estimated by focusing on gamma interaction phenomena and material non-uniformity problems. (author) [fr

  18. Lanthanide modification of CdSe/ZnS core/shell quantum dots

    DEFF Research Database (Denmark)

    Dethlefsen, Johannes Rytter; Mikhailovsky, Alexander A.; Burks, Peter T.

    2012-01-01

    Lanthanide-modified CdSe quantum dots (CdSe(Ln) QDs) have been prepared by heating a solution of Cd(oleate)(2), SeO2, and Ln(bipy)(S2CNEt2)(3) (bipy = 2,2'-bipyridine) to 180-190 degrees C for 10-15 min. The elemental compositions of the resulting CdSe(Ln) cores and CdSe(Ln)/ZnS core/shell QDs show...

  19. The Changes of Elements Composition in Aspergillus niger and Aspergillus terreus at Different Co2+, Cd2+ and Pb2+ Concentrations Using X-rays Microanalysis

    International Nuclear Information System (INIS)

    Ouda, S.M.

    2010-01-01

    X-ray microanalysis in electron microscope allows simultaneous detection and quantitative analysis of several elements so it contributes to understand the role of ions in physiological processes. Energy dispersive X-ray (EDX) analysis used to detect the changes in elements levels in Aspergillus niger and Aspergillus terreus when allowing to grow on Czapek's Dox liquid media amended with different Co 2+ , Cd 2+ and Pb 2+ concentrations and these changes may play a role in fungal uptake for these heavy metal ions. Results showed that Ca, Zn and Cu levels in both fungal isolates significantly decreased (P<0.05) when concentrations of used metal ions increased, also O, Na, Cl and K levels for A. niger and C and P for A. terreus recorded significant reduction (P<0.05) in their percentages. Also, the results revealed that, C and P for A. niger and O, Na, Mg, Cl and K levels for A. terreus significantly increased (P<0.05) as a result of increasing metal ions concentrations. Lack of Cd and Pb peaks in X-ray spectrum for A. terreus led this work to conclude that, A. niger was more effective than A. terreus in Co, Cd, Pb uptake into fungal biomass. The increase or decrease of levels of detected elements could be related to the difference between two fungal isolates in uptake certain heavy metal ion (Co, Cd, Pb)

  20. The Building Blocks of Metallothioneins: Heterometallic Zn(2+) and Cd(2+) clusters from first-principles calculations

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta; Rykær, Martin

    2010-01-01

    been characterized and ranked according to relative free energy and metal ion selectivity. The most stable distribution at low Cd2+ concentration is computed to be Zn4 + CdZn2, whereas at 2 : 1 Cd2+ : Zn2+ concentration, only heteroclusters are thermodynamically stable, explaining experimental data...

  1. Highly luminescent CdSe/ZnSe core-shell quantum dots of one-pot preparation in octadecene

    NARCIS (Netherlands)

    Zeng, Q.; Kong, X.; Zhang, Y.; Zhang, H.

    2008-01-01

    CdSe/ZnSe core-shell quantum dots were synthesized using a new one-pot procedure where the core was prepared in octadecene. A ZnSe shell around a CdSe nanoparticle was formed by the reaction of selenium-richness on the surfaces of CdSe nanoparticles with Zn2+ from the injected zinc stearate

  2. Surface passivation of HgCdTe by CdZnTe and its characteristics

    Science.gov (United States)

    Lee, T. S.; Choi, K. K.; Jeoung, Y. T.; Kim, H. K.; Kim, J. M.; Kim, Y. H.; Chang, J. M.; Song, W. S.; Kim, S. U.; Park, M. J.; Lee, S. D.

    1997-06-01

    In this paper, we report the results of capacitance-voltage measurements conducted on several metal-insulator semiconductor (MIS) capacitors in which HgCdTe surfaces are treated with various surface etching and oxidation processes. CdZnTe passivation layers were deposited on HgCdTe surfaces by thermal evaporation after the surfaces were etched with 0.5-2.0% bromine in methanol solution, or thin oxide layers (tox ˜ few ten Å) were grown on the surfaces, in order to investigate effects of the surface treatments on the electrical properties of the surfaces, as determined from capacitance-voltage (C-V) measurements at 80K and 1 MHz. A negative flat band voltage has been observed for MIS capacitors fabricated after etching of HgCdTe surfaces with bromine in methanol solutions, which is reported to make the surface Te-rich. It is inferred that residual Te on the surface is a positive charge, Te4+. C-V characteristics for MIS capacitors fabricated on oxide surfaces grown by air-exposure and electrolytic process have shown large hysteresis effects, from which it is inferred that imperfect and electrically active oxide compounds and HgTe particles near the surface become slow interface states.

  3. Cd and Zn interactions and toxicity in ectomycorrhizal basidiomycetes in axenic culture

    Directory of Open Access Journals (Sweden)

    Vinicius H. De Oliveira

    2018-03-01

    Full Text Available Background Metal contamination in soils affects both above- and belowground communities, including soil microorganisms. Ectomycorrhizal (ECM fungi are an important component in belowground community and tolerant strains have great potential in enhancing plant-based remediation techniques. We assessed cadmium and zinc toxicity in five ECM species in liquid media (Hebeloma subsaponaceum; H. cylindrosporum; H. crustuliniforme; Scleroderma sp.; Austroboletus occidentalis and investigated the potential of Zn to alleviate Cd toxicity. Due to highly divergent results reported in the literature, liquid and solid media were compared experimentally for the first time in terms of differential toxicity thresholds in Cd and Zn interactions. Methods A wide range of Cd and Zn concentrations were applied to ectomycorrhizal fungi in axenic cultures (in mg L−1: 0; 1; 3; 9; 27; 81; 243 for the Cd treatments, and 0; 1; 30; 90; 270; 810; 2,430 for Zn. Combined Zn and Cd treatments were also applied to H. subsaponaceum and Scleroderma sp. Dry weight was recorded after 30 days, and in case of solid medium treatments, radial growth was also measured. Results and Discussion All species were adversely affected by high levels of Cd and Zn, and A. occidentalis was the most sensitive, with considerable biomass decrease at 1 mg L−1 Cd, while Scleroderma sp. and H. subsaponaceum were the most tolerant, which are species commonly found in highly contaminated sites. Cd was generally 10 times more toxic than Zn, which may explain why Zn had little impact in alleviating Cd effects. In some cases, Cd and Zn interactions led to a synergistic toxicity, depending on the concentrations applied and type of media used. Increased tolerance patterns were detected in fungi grown in solid medium and may be the cause of divergent toxicity thresholds found in the literature. Furthermore, solid medium allows measuring radial growth/mycelial density as endpoints which are informative and in

  4. Composition and strain effects in Type I and Type II heterostructure ZnSe/Cd(Zn)S and ZnSe/Cd1-xZnxS core/shell quantum dots

    Science.gov (United States)

    Gheshlaghi, Negar; Pisheh, Hadi Sedaghat; Ünlü, Hilmi

    2017-11-01

    We investigated the effect of ternary shell alloy composition on the bandgap and diameter of core of ZnSe / Cd1 - x Znx S heterostructure core/shell quantum dots, which were synthesized by using a simple colloidal technique. Characterization by using the x-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis absorption and fluorescence emission spectroscopic techniques indicate that (i) there is a transition of ZnSe / Cd0.6 Zn0.4 S Type-I heterostructure (electrons and holes tend to localize in core) to ZnSe / Cd0.75 Zn0.25 S quasi-Type-II heterostructures (holes tend to localized in the core and electrons are delocalized) and (ii) then after large red shift and Stock-shift in PL emission spectra but not a distinct absorption peak in UV spectra become noticeable in ZnSe/Cd0.75Zn0.25 S quasi-Type II and ZnSe/CdS Type II heterostructures (electrons are localized in core and holes are localized in shell). Furthermore, the increase of Cd:S ratio in shell alloy composition shifts the XRD peaks to lower 2θ degrees which corresponds to tensile strain in the ZnSe core. Finally, the hydrostatic interfacial strain has effect on the squeezing or stretching the capped core: A decrease of compressive force on core from ZnSe/ZnS to tensile force in ZnSe/CdS with increase in Cd:S ratio indicates that transition of compressive strain to tensile strain takes place with the transition from Type-I to II heterostructure.

  5. Phosphine-free synthesis of high-quality reverse type-I ZnSe/CdSe core with CdS/Cd{sub x}Zn{sub 1-x}S/ZnS multishell nanocrystals and their application for detection of human hepatitis B surface antigen

    Energy Technology Data Exchange (ETDEWEB)

    Shen Huaibin; Niu Jin Zhong; Xu Shasha; Zhou Changhua; Li Linsong [Key Laboratory for Special Functional Materials, Henan University, Kaifeng 475004 (China); Yuan Hang; Ma Lan, E-mail: malan@sz.tsinghua.edu.cn, E-mail: lsli@henu.edu.cn [Life Science Division, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China)

    2011-09-16

    Highly photoluminescent (PL) reverse type-I ZnSe/CdSe nanocrystals (NCs) and ZnSe/CdSe/CdS/Cd{sub x}Zn{sub 1-x}S/ZnS core/multishell NCs were successfully synthesized by a phosphine-free method. By this low-cost, 'green' synthesis route, more than 10 g of high-quality ZnSe/CdSe/CdS/Cd{sub x}Zn{sub 1-x}S/ZnS NCs were synthesized in a large scale synthesis. After the overgrowth of a CdS/Cd{sub x}Zn{sub 1-x}S/ZnS multishell on ZnSe/CdSe cores, the PL quantum yields (QYs) increased from 28% to 75% along with the stability improvement. An amphiphilic oligomer was used as a surface coating agent to conduct a phase transfer experiment, core/multishell NCs were dissolved in water by such surface modification and the QYs were still kept above 70%. The as-prepared water dispersible ZnSe/CdSe/CdS/Cd{sub x}Zn{sub 1-x}S/ZnS core/multishell NCs not only have high fluorescence QYs but also are extremely stable in various physiological conditions. Furthermore, a biosensor system (lateral flow immunoassay system, LFIA) for the detection of human hepatitis B surface antigen (HBsAg) was developed by using this water-soluble core/multishell NCs as a fluorescent label and a nitrocellulose filter membrane for lateral flow. The result showed that such ZnSe/CdSe/CdS/Cd{sub x}Zn{sub 1-x}S/ZnS core/multishell NCs were excellent fluorescent labels to detect HBsAg. The sensitivity of HBsAg detection could reach as high as 0.05 ng ml{sup -1}.

  6. Multi-terminal Two-color ZnCdSe/ZnCdMgSe Based Quantum-well Infrared Photodetector

    Science.gov (United States)

    Kaya, Yasin; Ravikumar, Arvind; Chen, Guopeng; Tamargo, Maria C.; Shen, Aidong; Gmachl, Claire

    Target recognition and identification applications benefits from two-color infrared (IR) detectors in the mid and long-wavelength IR regions. Currently, InGaAs/AlGaAs and GaAs/AlGaAs multiple quantum wells (QWs) grown on GaAs substrate are the most commonly used two-color QW IR photodetectors (QWIPs). However, the lattice-mismatch and the buildup of strain limit the number of QWs that can be grown, in turn increasing the dark current noise, and limiting the device detectivity.In this work, we report on two-color QWIPs based on the large conduction band offset (~1.12ev) ZnCdSe/ZnCdMgSe material system lattice matched to InP. QWIPs were designed based on a bound to quasi-bound transition, centered at 4 μm and 7 μm and each QW is repeated 50 times to eliminate the high dark current and a contact layer is inserted between the two stacks of QWs for independent electrical contacts. Wafers are processed into two step rectangular mesas by lithography and wet etching. Experiments showed absorption spectra centered at 4.9 μm and 7.6 μm at 80 K and the full width at half maximums were Δλ / λ = 21 % and Δλ / λ = 23 % , respectively. Current work studies the Johnson and the background noise limited detectivities of these QWIPs. Current address: School of Earth, Energy and Environmental Sciences, Stanford, CA 94305, USA.

  7. Content of Pb, Cd and Cl in forest trees caused by the traffic of motor vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Mankovska, B

    1977-01-01

    The contents of Pb, Cd in spruce trees and soil polluted by the traffic of motor vehicles was determined by the method of atomic absorption, that of Cl by the mercurometric method. In general the raised level of Pb, Cd and Cl was found in the soils and assimilation organs close to the roadway. The most important factors influencing this raise are mentioned: the age of needles, season of year, character of surface of plant organs, tree species, both horizontal and vertical distance from the road. There is a statistically very high significant relation (at 95% level of significance) between the amount of Pb and Cd in mg in mg.kg/sup -1/ and horizontal distance from the road; that of Cl is lower.

  8. Stabilization of lead (Pb) and zinc (Zn) in contaminated rice paddy soil using starfish: A preliminary study.

    Science.gov (United States)

    Moon, Deok Hyun; Hwang, Inseong; Koutsospyros, Agamemnon; Cheong, Kyung Hoon; Ok, Yong Sik; Ji, Won Hyun; Park, Jeong-Hun

    2018-05-01

    Lead (Pb) and zinc (Zn) contaminated rice paddy soil was stabilized using natural (NSF) and calcined starfish (CSF). Contaminated soil was treated with NSF in the range of 0-10 wt% and CSF in the range of 0-5 wt% and cured for 28 days. Toxicity characteristic leaching procedure (TCLP) test was used to evaluate effectiveness of starfish treatment. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) analyses were conducted to investigate the mechanism responsible for effective immobilization of Pb and Zn. Experimental results suggest that NSF and CSF treatments effectively immobilize Pb and Zn in treated rice paddy soil. TCLP levels for Pb and Zn were reduced with increasing NSF and CSF dosage. Comparison of the two treatment methods reveals that CSF treatment is more effective than NSF treatment. Leachability of the two metals is reduced approximately 58% for Pb and 51% for Zn, upon 10 wt% NSF treatment. More pronounced leachability reductions, 93% for Pb and 76% for Zn, are achieved upon treatment with 5 wt% CSF. Sequential extraction results reveal that NSF and CSF treatments of contaminated soil generated decrease in exchangeable/weak acid Pb and Zn soluble fractions, and increase of residual Pb and Zn fractions. Results for the SEM-EDX sample treated with 5 wt% CSF indicate that effective Pb and Zn immobilization is most probably associated with calcium silicate hydrates (CSHs) and calcium aluminum hydrates (CAHs). Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Nanostructure CdS/ZnO heterojunction configuration for photocatalytic degradation of Methylene blue

    Science.gov (United States)

    Velanganni, S.; Pravinraj, S.; Immanuel, P.; Thiruneelakandan, R.

    2018-04-01

    In the present manuscript, thin films of Zinc Oxide (ZnO) have been deposited on a FTO substrate using a simple successive ionic layer adsorption and reaction (SILAR) and chemical bath deposition (CBD) method. Cadmium Sulphide (CdS) nanoparticles are sensitized over ZnO thin films using SILAR method. The synthesized nanostructured CdS/ZnO heterojunction thin films was characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), UV-Vis spectroscopy and Raman spectroscopy techniques. The band gap of CdS nanoparticles over ZnO nanostructure was found to be about 3.20 eV. The photocatalytic activities of the deposited CdS/ZnO thin films were evaluated by the degradation of methylene blue (MB) in an aqueous solution under sun light irradiation.

  10. Synthesis, characterization and charge transport mechanism of CdZnO nanorods

    International Nuclear Information System (INIS)

    Mahmoud, Waleed E.; Al-Ghamdi, A.A.; El-Tantawy, F.; Al-Heniti, S.

    2009-01-01

    ZnO and Cd-doped ZnO nanostructures were prepared by new facile method at 80 deg. C. XRD measurement indicated that both samples had typical hexagonal wurtzite structures. Transmission electron microscopy (TEM) measurement shows that rod-like crystals have been formed. EDX measurement confirms the incorporation of the cadmium ion into the crystalline lattice of ZnO and indicated that cadmium ions uniformly distributed on the surface of the rods. The doping with cadmium ions has a great influence on the optical properties of the ZnO. The electrical measurements of Cd-doped ZnO nanorod were measured. The current-voltage (I-V) characteristic curve revealed that the charge transport above 4 V is mainly non-linear due to grain boundary contribution. The complex impedance spectroscopy was confirmed that the grain boundary effect controls the charge transport mechanism through CdZnO ceramic material.

  11. Uptake pathways and toxicity of Cd and Zn in the earthworm Eisenia fetida.

    NARCIS (Netherlands)

    Li, L.-Z.; Zhou, D.-M.; Peijnenburg, W.J.G.M.; Wang, P.; van Gestel, C.A.M.; Jin, S.-Y.; Wang, Q.-Y.

    2010-01-01

    The uptake of Cd and Zn by the earthworm Eisenia fetida was determined at varying Ca concentrations and with pre-exposure to different metabolic inhibitors in simulated soil solutions over a 48-h period. The presence of Ca in the solution had complex actions on Cd uptake. At a low Cd concentration

  12. Study of the potential of barnyard grass for the remediation of Cd- and Pb-contaminated soil.

    Science.gov (United States)

    Xu, Jianling; Cai, Qiongyao; Wang, Hanxi; Liu, Xuejun; Lv, Jing; Yao, Difu; Lu, Yue; Li, Wei; Liu, Yuanyuan

    2017-05-01

    In this study, the microwave digestion method was used to determine total cadmium (Cd) and lead (Pb) concentrations, the BCR method was used to determine different states of Cd and Pb, and atomic absorption spectroscopy (AAS) and inductively coupled plasma optical emission spectrometry (ICP-OES) were used to determine Cd and Pb concentrations in simulated soil and barnyard grass before and after planting barnyard grass to provide a theoretical basis for the remediation of Cd- and Pb-contaminated soil. The results showed that the bioconcentration factor changes with different Cd concentrations are relatively complex and that the removal rate increases regularly. The 100 mg kg -1 Cd treatment had the highest removal rate, which reached 36.66%. For Pb, the bioconcentration factor decreased and tended to reach equilibrium as the Pb concentration increased. The highest removal rate was 41.72% and occurred in the 500 mg kg -1 Pb treatment; however, this removal rate was generally lower than that of Cd. In addition, the reduction state had the highest change rate, followed by the residual, acid soluble and oxidation states. For Pb, the residual state has the highest change rate, followed by the acid soluble state, reduction state and oxidation state. In addition, a significant correlation was observed between the soil Pb and Cd concentrations and the concentrations of Pb and Cd that accumulated in the belowground biomass of the barnyard grass, but no significant correlation was observed between the soil Pb and Cd concentrations and the amounts of Pb and Cd that accumulated in the aboveground biomass of the barnyard grass. The highest transfer factor of Cd was 0.49, which occurred in the 5 mg kg -1 Cd treatment. The higher transfer factor of Pb was 0.48 in the 100 mg kg -1 Pb treatment. All of these factors indicate that the belowground biomass of barnyard grass plays a more important role in the remediation of Cd- and Pb-contaminated soils than the aboveground

  13. Comparative adsorption of Pb2+ and Cd2+ by cow manure and its vermicompost.

    Science.gov (United States)

    Zhu, Weiqin; Du, Wenhui; Shen, Xuyang; Zhang, Hangjun; Ding, Ying

    2017-08-01

    Organic waste has great potential for use as an amendment to immobilize heavy metals in the environment. Therefore, this study investigates various properties of cow manure (CM) and its derived vermicompost (CV), including the pH, cationic exchangeable capacity (CEC), elemental composition and surface structure, to determine the potential of these waste products to remove Pb 2+ and Cd 2+ from solution. The results demonstrate that CV has a much higher pH, CEC and more irregular pores than CM and is enriched with minerals and ash content but has a lower C, H, O and N content. Adsorption isotherms studies shows that the adsorption of Pb 2+ and Cd 2+ onto either CM or CV follows a Langmuir model and presents maximum Pb 2+ and Cd 2+ adsorption capacities of 102.77 mg g -1 and 38.11 mg g -1 onto CM and 170.65 and 43.01 mg g -1 onto CV, respectively. Kinetic studies show that the adsorption of Pb 2+ onto CM and CV fits an Elovich model, whereas the adsorption of Cd 2+ onto CM and CV fits a pseudo-second-order model. Desorption studies indicate that CV is more effective than CM in removing Pb 2+ and Cd 2+ . FTIR analysis demonstrates that the adsorption of Pb 2+ and Cd 2+ onto CM mainly depends on existed aliphatic alcohol, aromatic acid as well as new produced carbonates, whereas that onto CV may be contributed by the existed aliphatic alcohol, aromatic acids as well as some carbonates and phosphates. Thus, vermicomposting disposal of cow manure with destination mineral addition may broaden the way of its recycle and environmental usage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Modelling the leaching of Pb, Cd, As, and Cr from cementitious waste using PHREEQC

    International Nuclear Information System (INIS)

    Halim, Cheryl E.; Short, Stephen A.; Scott, Jason A.; Amal, Rose; Low, Gary

    2005-01-01

    A leaching model was developed using the United States Geological Survey public domain PHREEQC geochemical package to simulate the leaching of Pb, Cd, As, and Cr from cementitious wastes. The model utilises both kinetic terms and equilibrium thermodynamics of key compounds and provides information on leachate and precipitate speciation. The model was able to predict the leaching of Pb, Cd, As, and Cr from cement in the presence of both simple (0.1 and 0.6 M acetic acid) and complex municipal landfill leachates. Heavy metal complexation by the municipal landfill leachate was accounted for by the introduction of a monoprotic organic species into the model. The model indicated Pb and As were predominantly incorporated within the calcium silicate hydrate matrix while a greater portion of Cd was seen to exist as discrete particles in the cement pores and Cr (VI) existed mostly as free CrO 4 2- ions. Precipitation was found to be the dominant mechanism controlling heavy metal solubility with carbonate and silicate species governing the solubility of Pb and carbonate, silicate and hydroxide species governing the solubility of Cd. In the presence of acetic acid, at low pH values Pb and Cd acetate complexes were predominant whereas, at high pH values, hydroxide species dominated. At high pH values, the concentration of As in the leachate was governed by the solubility of Ca 3 (AsO 4 ) 2 with the presence of carbonate alkalinity competing with arsenate for Ca ions. In the presence of municipal landfill leachate, Pb and Cd organic complexes dominated the heavy metal species in solution. The reduction of As and Cr in municipal landfill leachate was crucial for determining aqueous speciation, with typical municipal landfill conditions providing the reduced forms of As and Cr

  15. X-ray fluorescence analysis of Pb, Fe and Zn in kohl

    Directory of Open Access Journals (Sweden)

    Eman Daar

    Full Text Available Kohl, a facial salve used in ancient times as a symbol of affluence, now enjoys more widespread traditional followings, for cosmetic, religious and supposed medicinal purposes. Popularly used by women and men of all ages, particularly those of North African, Middle Eastern, Southern Asia, Japanese and Chinese origins, it is also known to be used on neonates and children from such populations. With small-scale producers of kohl possessing a growing awareness of the adverse market impact of products that contain (lead Pb and other toxicity related elements, some claim their products to be Pb-free, offering an apparent change from the more traditional galena-based (lead sulphide media. Among the published physiological effects of exposure to Pb is that it replaces Ca in bones and teeth, making them weak and fragile, other impacts including nephrotoxicity, also linked with increased Pb blood levels in studies in Oman, Canada, Saudi Arabia, India and Pakistan. Current study involves XRF analysis of Pb, Fe and Zn concentrations in 135 samples of kohl from nine randomly selected suppliers (15 samples of each brand being represented. In pursuit of this, use was made of an in-house assembled facility comprising compact high-performance components, the arrangement offering sufficient sensitivity for the purposes of present study. In most of the samples investigated in the present study observation has been made of concentrations of Pb at elevated levels, quantification of those levels also demonstrating a need to address self-attenuation by the Pb itself. Significant concentration of Fe have also been found in several of the samples. Keywords: X-ray florescence, Pb, Fe and Zn contamination, Kohl

  16. Use of cattails in treating wastewater from a Pb/Zn mine

    Science.gov (United States)

    Lan, Chongyu; Chen, Guizhu; Li, Liuchun; Wong, M. H.

    1992-01-01

    This article describes the use of a combined treatment system, which includes an aquatic treatment pond with Typha latifolia Linn. (Typhaceae) as the dominant species and a stabilization pond, to treat the wastewater from a Pn/Zn mine at Shaoguan, Guangdong Province, China. In 1983, it was noted that T. latifolia bloomed in areas affected by the wastewater emitted from the mine, hence a combined purification system was subsequently built. The influent contained high levels of total suspended solids (4635 mg/liter), chemical oxygen demand (14.5 mg/liter) as well as Pb (1.6 mg/liter) and Zn (1.9 mg/liter). The results of the effluent after treatment showed that the total suspended solids, chemical oxygen demand, Pb, and Zn had been reduced by 99%, 55%, 95%, and 80% respectively. The results of plant tissue analysis indicled that T. latifolia assimilated significant amounts of Pb and Zn, especially in the root portion. During 1986 several species of algae and fish were present in the pond, usually with a higher density in areas containing lower metal concentrations in the water.

  17. Polarization effect of CdZnTe imaging detector based on high energy γ source

    International Nuclear Information System (INIS)

    Li Miao; Xiao Shali; Wang Xi; Shen Min; Zhang Liuqiang; Cao Yulin; Chen Yuxiao

    2011-01-01

    The inner electric potential distribution of CdZnTe detector was derived by applying poisson equation with the first type boundary condition, and the polarization effect of CdZnTe pixellated detector for imaging 137 Cs γ source was investigated. The results of numerical calculation and experiment indicate that electric potential distribution is mainly influenced by applied bias for low charge density in CdZnTe crystal and, in turn, there is linear relationship between electric potential distribution and applied bias that induces uniform electric field under low irradiated flux. However, the electric potential appears polarization phenomenon, and the electric field in CdZnTe crystal is distorted when CdZnTe detector is under high irradiated flux. Consequently, charge carriers in CdZnTe crystal drift towards the edge pixels of irradiated region, and hence, the shut-off central pixels are surrounded by a ring of low counting pixels. The polarization effect indeed deteriorates the performance of CdZnTe detector severely and the event counts of edge pixels for irradiated region reduce about 70%. (authors)

  18. CdZnTe background measurements at balloon altitudes with PoRTIA

    International Nuclear Information System (INIS)

    Parsons, A.; Barthelmy, S.; Bartlett, L.; Gehrels, N.; Naya, J.; Stahle, C.M.; Tueller, J.; Teegarden, B.

    2004-01-01

    Measurements of the CdZnTe internal background at balloon altitudes are essential to determine which physical processes make the most important background contributions. We present results from CdZnTe background measurements made by PoRTIA, a small CdZnTe balloon instrument that was flown three times in three different shielding configurations. PoRTIA was passively shielded during its first flight from Palestine, Texas and actively shielded as a piggyback instrument on the GRIS balloon experiment during its second and third flights from Alice Springs, Australia, using the thick GRIS NaI anticoincidence shield. A significant CdZnTe background reduction was achieved during the third flight with PoRTIA placed completely inside the GRIS shield and blocking crystal, and thus completely surrounded by 15 cm of NaI. A unique balloon altitude background data set is provided by CdZnTe and Ge detectors simultaneously surrounded by the same thick anticoincidence shield; the presence of a single coaxial Ge detector inside the shield next to PoRTIA allowed a measurement of the ambient neutron flux inside the shield throughout the flight. These neutrons interact with the detector material to produce isomeric states of the Cd, Zn, and Te nuclei that radiatively decay; calculations are presented to determine the relative contribution of these decays to the fully shielded CdZnTe background measured by PoRTIA

  19. Hydrothermal Pb-Zn sulphide mineralization on the site Marianka (Small Carpathians); Hydrotermalna Pb-Zn sulfidicka mineralizacia na lokalite Marianka (Male Karpaty)

    Energy Technology Data Exchange (ETDEWEB)

    Kubac, A [Univerzita Komenskeho v Bratislave, Prirodovedecka fakulta, Katedra mineralogie a petrologie, 84215 Bratislava (Slovakia)

    2012-04-25

    Hydrothermal Pb-Zn sulphide mineralization at Marianka village in Small Carpathians occurs in Palaeozoic metapelit rocks of Tatricum crystalline. Mineralization consists of ore lenses. Banded texture of ores is typical. The main ore minerals are sphalerite and galenite accompanied by bournonit, boulangerit, meneghinit, pyrite, chalcopyrite, tetrahedrite, marcasite and pyrotite. Quartz is the main non-metallic mineral. Other non-metallic minerals are calcite, ankerite, siderite and dolomite. Micro-thermometric measurements of fluid inclusions in quartz indicate creation of mineralization probably from low salinic fluids (0.1 to 20 wt.% NaCl equiv.), at 100 to 150 grad C. (authors)

  20. CdSe/ZnSe quantum dot structures grown by molecular beam epitaxy with a CdTe submonolayer stressor

    International Nuclear Information System (INIS)

    Sedova, I. V.; Lyublinskaya, O. G.; Sorokin, S. V.; Sitnikova, A. A.; Toropov, A. A.; Donatini, F.; Dang, Si Le; Ivanov, S. V.

    2007-01-01

    A procedure for formation of CdSe quantum dots (QDs) in a ZnSe matrix is suggested. The procedure is based on the introduction of a CdTe submonolayer stressor deposited on the matrix surface just before deposition of the material of the QDs. (For CdTe/ZnSe structure, the relative lattice mismatch is Δa/a ∼ 14%.) The stressor forms small strained islands at the ZnSe surface, thus producing local fields of high elastic stresses controlling the process of the self-assembling of the QDs. According to the data of transmission electron microscopy, this procedure allows a considerable increase in the surface density of QDs, with a certain decrease in their lateral dimensions (down to 4.5 ± 1.5 nm). In the photoluminescence spectra, a noticeable (∼150 meV) shift of the peak to longer wavelengths from the position of the reference CdSe/ZnSe QD structure is observed. The shift is due to some transformation of the morphology of the QDs and an increase in the Cd content in the QDs. Comprehensive studies of the nanostructures by recording and analyzing the excitation spectra of photoluminescence, the time-resolved photoluminescence spectra, and the cathodoluminescence spectra show that the emission spectra involve two types of optical transitions, namely, the type-I transitions in the CdSeTe/ZnSe QDs and the type-II transitions caused mainly by the low cadmium content (Zn,Cd)(Se,Te)/ZnSe layer formed between the QDs

  1. Phase equilibria in TlX-Cd(Zn)X (X-S, Se, Te) systems

    International Nuclear Information System (INIS)

    Gusejnov, F.Kh.; Babanly, M.B.; Kuliev, A.A.

    1982-01-01

    The methods of DTA, RPA and measurement of the alloys microhardness have been used to investigate the phase equilibria in the TlX-Zn(Cd)X systems. It is established that the TlZn(Cd)X 2 compounds, the presence of which is mentioned in the literature earlier, do not form in these systems. The TlSe-Zn(Cd)Se systems apply to the simple eutectic type and characterized by digenerated eutectic near the TlSe. Thermodynamical analysis of the liquidus of the TlSe-CdSe and TlTe-Zn(Cd)Te systems in approximation of the regular solutions, taking into account the dissociation of tallium chalcogenides in liquid phase, is made

  2. The effect of Pb addition on the morphology of CdSe quantum dot

    Science.gov (United States)

    Kim, Young-Kuk; Cho, Young-Sang; Chung, Kookchae; Choi, Chul-Jin

    2010-08-01

    CdSe quantum dots had been synthesized with a hot injection method. It was shown that the addition of Pb ions in the initial precursor solution changed the morphology of CdSe nanocrystals from slightly prolate ellipsoid to branched rod. Photoluminescence (PL) of the branched nanocrystals showed rapid depression of emission intensity due to the morphological development to the branched nanocrystal induced by Pb addition. Low temperature PL spectrum indicated that the surface recombination of charge carrier resulted in the large depression of emission from the branched nanocrystal.

  3. Formation of self assembled PbTe quantum dots in CdTe on Si(111)

    Science.gov (United States)

    Felder, F.; Fognini, A.; Rahim, M.; Fill, M.; Müller, E.; Zogg, H.

    2010-01-01

    We describe the growth and formation of self assembled PbTe quantum dots in a CdTe host on a silicon (111) substrate. Annealing yields different photoluminescence spectra depending on initial PbTe layer thickness, thickness of the CdTe cap layer and annealing temperature. Generally two distinct emission peaks at ˜0.3 eV and ˜0.45 eV are visible. Model calculations explaining their temperature dependence are performed. The dot size corresponds well with the estimated sizes from electron microscopy images. The quantum dots may be used as absorber within a mid-infrared detector.

  4. Vertically aligned ZnO@CdS nanorod heterostructures for visible light photoinactivation of bacteria

    International Nuclear Information System (INIS)

    Zirak, M.; Akhavan, O.; Moradlou, O.; Nien, Y.T.; Moshfegh, A.Z.

    2014-01-01

    Highlights: • Synthesis of vertically aligned ZnO@CdS nanorod heterostructures. • Effective antibacterial application of the ZnO@CdS nanorods under visible light irradiation. • Determination of the optimum loading of CdS on the ZnO nanorods in the antibacterial application. -- Abstract: Vertically aligned ZnO@CdS nanorod heterostructure films with various loadings of CdS nanoparticle shell were synthesized and applied in photoinactivation of Escherichia coli bacteria under visible light irradiation. While neither the bare ZnO nanorods (with band-gap energy (E g ) of ∼3.28 eV) under visible light irradiation nor the nanorod heterostructures in dark exhibited any significant antibacterial activity, the ZnO@CdS nanorod heterostructures (with E g ∼2.5–2.6 eV) could successfully inactivate the bacteria under visible light irradiation. Furthermore, it was found that an optimum loading of the CdS shell (corresponding to the effective thickness less than ∼15 nm) is required to achieve a complete inactivation of the bacteria after 24 h visible light irradiation at room temperature. Using X-ray photoelectron spectroscopy, the lower photoinactivation efficiencies of the ZnO@CdS nanorod heterostructure at CdS thicknesses lower and higher than the optimum one were assigned to lower amounts of CdS nanoparticles and OH bonds (substantially existed on the hydrothermally synthesized ZnO nanorods) which are responsible for absorption of the visible light and production of hydroxyl radicals, respectively. Water contact angle measurements showed that the sample with more surface OH groups has a more hydrophilic surface and so more antibacterial activity

  5. Vertically aligned ZnO@CdS nanorod heterostructures for visible light photoinactivation of bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Zirak, M. [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Akhavan, O., E-mail: oakhavan@sharif.edu [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-89694, Tehran (Iran, Islamic Republic of); Moradlou, O. [Department of Chemistry, Faculty of Sciences, Alzahra University, P.O. Box 1993893973, Tehran (Iran, Islamic Republic of); Nien, Y.T. [Department of Materials Science and Engineering, National Formosa University, Huwei District, Taiwan (China); Moshfegh, A.Z. [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-89694, Tehran (Iran, Islamic Republic of)

    2014-03-25

    Highlights: • Synthesis of vertically aligned ZnO@CdS nanorod heterostructures. • Effective antibacterial application of the ZnO@CdS nanorods under visible light irradiation. • Determination of the optimum loading of CdS on the ZnO nanorods in the antibacterial application. -- Abstract: Vertically aligned ZnO@CdS nanorod heterostructure films with various loadings of CdS nanoparticle shell were synthesized and applied in photoinactivation of Escherichia coli bacteria under visible light irradiation. While neither the bare ZnO nanorods (with band-gap energy (E{sub g}) of ∼3.28 eV) under visible light irradiation nor the nanorod heterostructures in dark exhibited any significant antibacterial activity, the ZnO@CdS nanorod heterostructures (with E{sub g} ∼2.5–2.6 eV) could successfully inactivate the bacteria under visible light irradiation. Furthermore, it was found that an optimum loading of the CdS shell (corresponding to the effective thickness less than ∼15 nm) is required to achieve a complete inactivation of the bacteria after 24 h visible light irradiation at room temperature. Using X-ray photoelectron spectroscopy, the lower photoinactivation efficiencies of the ZnO@CdS nanorod heterostructure at CdS thicknesses lower and higher than the optimum one were assigned to lower amounts of CdS nanoparticles and OH bonds (substantially existed on the hydrothermally synthesized ZnO nanorods) which are responsible for absorption of the visible light and production of hydroxyl radicals, respectively. Water contact angle measurements showed that the sample with more surface OH groups has a more hydrophilic surface and so more antibacterial activity.

  6. Dynamic adsorption of mixtures of Rhodamine B, Pb (II), Cu (II) and Zn(II) ions on composites chitosan-silica-polyethylene glycol membrane

    Science.gov (United States)

    Mahatmanti, F. W.; Rengga, W. D. P.; Kusumastuti, E.; Nuryono

    2018-04-01

    The adsorption of a solution mixture of Rhodamine B, Pb (II), Cu (II) and Zn(II) was studied using dynamic methods employing chitosan-silica-polyethylene glycol (Ch/Si/P) composite membrane as an adsorptive membrane. The composite Ch/Si/P membrane was prepared by mixing a chitosan-based membrane with silica isolated from rice husk ash (ASP) and polyethylene glycol (PEG) as a plasticizer. The resultant composite membrane was a stronger and more flexible membrane than the original chitosan-based membrane as indicated by the maximum percentage of elongation (20.5 %) and minimum Young’s Modulus (80.5 MPa). The composite membrane also showed increased mechanical and hydrophilic properties compared to the chitosan membranes. The membrane was used as adsorption membrane for Pb (II), Cu (II), Cd (II) ions and Rhodamine B dyes in a dynamic system where the permeation and selectivity were determined. The permeation of the components was observed to be in the following order: Rhodamine B > Cd (II) > Pb (II) > Cu (II) whereas the selectivity was shown to decrease the order of Cu (II) > Pb (II) > Cd (II) > Rhodamine B.

  7. Numerical study of the influence of ZnTe thickness on CdS/ZnTe solar cell performance

    Science.gov (United States)

    Skhouni, Othmane; El Manouni, Ahmed; Mari, Bernabe; Ullah, Hanif

    2016-05-01

    At present most of II-VI semiconductor based solar cells use the CdTe material as an absorber film. The simulation of its performance is realized by means of various numerical modelling programs. We have modelled a solar cell based on zinc telluride (ZnTe) thin film as absorber in substitution to the CdTe material, which contains the cadmium element known by its toxicity. The performance of such photovoltaic device has been numerically simulated and the thickness of the absorber layer has been optimized to give the optimal conversion efficiency. A photovoltaic device consisting of a ZnTe layer as absorber, CdS as the buffer layer and ZnO as a window layer was modelled through Solar Cell Capacitance Simulator Software. Dark and illuminated I-V characteristics and the results for different output parameters of ZnO/CdS/ZnTe solar cell were analyzed. The effect of ZnTe absorber thickness on different main working parameters such as: open-circuit voltage Voc, short-circuit current density Jsc, fill factor FF, photovoltaic conversion efficiency η was intensely studied in order to optimize ZnTe film thickness. This study reveals that increasing the thickness of ZnTe absorber layer results in higher efficiency until a maximum value and then decreases slightly. This maximum was found to be 10% at ZnTe optimum thickness close to 2 µm. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  8. Optical studies on Zn-doped lead chalcogenide (PbSe){sub 100−x}Zn{sub x} thin films composed of nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ashraf, Md. Tanweer [Department of Applied Sciences and Humanities, Jamia Millia Islamia (JMI), New Delhi-25 (India); Salah, Numan A. [Center of Nanotechnology, King Abdulaziz University, Jeddah (Saudi Arabia); Rafat, M. [Department of Applied Sciences and Humanities, Jamia Millia Islamia (JMI), New Delhi-25 (India); Zulfequar, M. [Department of Physics, Jamia Millia Islamia, New Delhi-25 (India); Khan, Zishan H., E-mail: zishan_hk@yahoo.co.in [Department of Applied Sciences and Humanities, Jamia Millia Islamia (JMI), New Delhi-25 (India)

    2016-08-01

    The effect of laser-Irradiation on the optical properties of Zn-doped PbSe thin films composed of nanoparticles has been studied. Scanning electron microscope (SEM) investigations suggest the formation of nanoparticles of average size of 50 nm for all the studied Zn compositions. XRD studies show that the as-prepared thin films are polycrystalline in nature. The formation of nanoparticles of Zn-doped PbSe has been confirmed by indexing the crystal planes as observed in the XRD spectra. The addition of Zn in (PbSe){sub 100−x}Zn{sub x} thin films result in the blue shift in photoluminescence spectra, this blue shift is associated with the narrowing of the band gap. Optical absorption measurements reveal a direct band gap for the present samples, which decreases on increasing the Zn content. The same trend has also been observed for the samples irradiated with laser. Further, the calculated values of Urbach energy are found to increase with the increase in Zn contents for the as-prepared as well as laser-irradiated samples. All the above observations agree well with the results of optical band gap and suggest that the decrease in band gap may be due to increase in band tails, defects and particle size. - Highlights: • Nanoparticles of Zn doped (PbSe){sub 100−x}Zn{sub x} lead chalcogenides have been synthesized. • Effect of laser irradiation on optical properties of (PbSe){sub 100−x}Zn{sub x} has been studied. • A blue shift in PL spectra is obtained on Zn incorporation.

  9. Hercynian Pb-Zn mineralization types in the Alcudia Valley mining district (Spain) and their reflect in Pb isotopic signatures

    Science.gov (United States)

    García de Madinabeitia, S.; Santos Zalduegui, J. F.; Palero, F.; Gil Ibarguchi, J. I.; Carracedo, M.

    2003-04-01

    More than 450 ore deposits indexed within the Alcudia Valley of the Central-Iberian Zone (Spain) may be grouped by their tectonic and lithologic characteristics (1,2) as follows: type A of rare stratabound mineralizations, and types B, C, D and E represented by abundant Hercynian veins (post-Namurian). 86 new Pb isotope analyses of galenas from the four vein types reveal that types B and C have similar isotopic ratios with values of μ_2 = 10.07, ω_2 = 40.6 and a mean model age of 564 Ma. Types D and E have μ_2 and ω_2 values of 9.79 and 38.5, respectively, but differ each other with respect to their model ages, 600 Ma (type D) and 335 Ma (type E). The observed variations appear to be related to the geochemical features of the metasedimentary host-rocks of the mineralizations where two distinct types of Pb isotopic ratios have been reported (3): one with μ_2 and ω_2 comparable to those of the D and E types and another with a more radiogenic composition, close to those of the B and C types of galenas. Nägler et al. have suggested partial rehomogeneization of Pb isotopic composition within the metasediments at ca. 330 Ma, that is, prior to the mineralization events, but the extent of this process and its effects on the ore bodies isotopic features is not evident. The origin of the more abundant E type ore bodies has been related to the Hercynian granitic rocks in the area (2, and references therein). Other plutons within this sector of the Central Iberian Zone (e.g., Linares, etc.; cf. accompanying Abstract) associate ore bodies whose Pb isotopic composition is very similar to that of the E type galenas from the Alcudia Valley. The isotopic data obtained thus point to a related or common source material for the various types of granites within the area studied. Yet, the Pb isotopic composition of other mineralizations (B, C, D), likewise located in Hercynian veins, allow to consider different types of Pb-Zn ore bodies and point therefore to different sources of

  10. Origin and tectonic implications of the Zhaxikang Pb-Zn-Sb-Ag deposit in northern Himalaya: evidence from structures, Re-Os-Pb-S isotopes, and fluid inclusions

    Science.gov (United States)

    Zhou, Qing; Li, Wenchang; Qing, Chengshi; Lai, Yang; Li, Yingxu; Liao, Zhenwen; Wu, Jianyang; Wang, Shengwei; Dong, Lei; Tian, Enyuan

    2018-04-01

    The Zhaxikang Pb-Zn-Sb-Ag-(Au) deposits, located in the eastern part of northern Himalaya, totally contain more than 1.146 million tonnes (Mt) of Pb, 1.407 Mt of Zn, 0.345 Mt of Sb, and 3 kilotonnes (kt) of Ag. Our field observations suggest that these deposits are controlled by N-S trending and west- and steep-dipping normal faults, suggesting a hydrothermal rather than a syngenetic sedimentary origin. The Pb-Zn-Sb-Ag-(Cu-Au) mineralization formed in the Eocene as indicated by a Re-Os isochron age of 43.1 ± 2.5 Ma. Sulfide minerals have varying initial Pb isotopic compositions, with (206Pb/204Pb)i of 19.04-19.68, (207Pb/204Pb)i of 15.75-15.88, and (208Pb/204Pb)i of 39.66-40.31. Sulfur isotopic values display a narrow δ34S interval of +7.8-+12.2‰. These Pb-S isotopic data suggest that the Zhaxikang sources of Pb and S should be mainly from the coeval felsic magmas and partly from the surrounding Mesozoic strata including metasedimentary rocks and layered felsic volcanic rocks. Fluid inclusion studies indicate that the hydrothermal fluids have medium temperatures (200-336 °C) but varying salinities (1.40-18.25 wt.% NaCl equiv.) with densities of 0.75-0.95 g/cm3, possibly suggesting an evolution mixing between a high salinity fluid, perhaps of magmatic origin, with meteoric water.

  11. 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.

  12. Solution processable RGO-CdZnS composite for solar light responsive photocatalytic degradation of 4-Nitrophenol

    Science.gov (United States)

    Ibrahim, Sk; Chakraborty, Koushik; Pal, Tanusri; Ghosh, Surajit

    2017-05-01

    We report the one pot single step synthesis and characterization of solution processable reduced graphene oxide (RGO) - cadmium zinc sulfide (CdZnS) nanocomposite materials. The composite was characterized structurally and morphologically by XRD and TEM studies. The reduction of GO in RGO-CdZnS composite, was confirmed by XPS and Raman spectroscopy. The photocatalytic activity of the RGO-CdZnS composite was investigated towards the degradation of 4-Nitrophenol. A notable increase of photocatalytic efficiency of RGO-CdZnS compare to controlled CdZnS was observed. Here RGO plays a crucial role to efficient photo induced charge separation from the CdZnS, and decreases the electron-hole recombination probability and subsequently enhanced the photocatalytic activity of the RGO-CdZnS composite material under simulated solar light irradiation. This work highlights the potential application of RGO-based materials in the field of photocatalytic degradation of organic water pollutant.

  13. Interface chemistry of CdZnTe films studied by a peel-off approach

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Jun; Xu, Haitao; Zhang, Yuelu; Ji, Huanhuan; Xu, Run, E-mail: runxu@staff.shu.edu.cn; Huang, Jian; Zhang, Jijun; Liang, Xiaoyan; Tang, Ke; Wang, Linjun, E-mail: ljwang@shu.edu.cn

    2016-12-01

    Highlights: • A peel-off approach is adopted to study the interface chemistry of CdZnTe films. • A thick mixed interlayer above 84 nm is found at a low growth temperature of 200 °C. • A reaction-limited model is suggested to explain the formation of mixed interlayer. - Abstract: CdZnTe films with thickness above 50 μm were deposited at temperatures of 200–500 °C by Close Space Sublimation method. A peel-off approach has been adopted to study the interface chemistry of CdZnTe thick films. For all the CdZnTe films, the scanning electron microscopy images show the small and round-like grains formed at interface in contrast to the large ordered grains at surface. For CdZnTe films grown at a low substrate temperature of 200 °C, the interface layer between CdZnTe and substrate is mixed with Te and CdTe, as evidenced by X-ray diffraction, Raman and X-ray photoelectron spectroscopy results. The thickness of the interface layer can be estimated to be 84 nm by depth profile using X-ray photoelectron spectroscopy. In contrast, a thin interface layer less than 14 nm is found at a high substrate temperature of 500 °C. The limited reaction of Te{sub 2} and Cd (Zn) to CdZnTe at a low growth temperature is responsible for the formation of the thick interface layer and a slow deposition rate at the nucleation stage.

  14. Field evaluation of Cd and Zn phytoextraction potential by the hyperaccumulators Thlaspi caerulescens and Arabidopsis halleri

    International Nuclear Information System (INIS)

    McGrath, S.P.; Lombi, E.; Gray, C.W.; Caille, N.; Dunham, S.J.; Zhao, F.J.

    2006-01-01

    Field trials were undertaken to investigate the effect of the application of metal mobilizing agents, different sowing strategies and length of growing season on the extraction of Cd and Zn from soils by Thlaspi caerulescens and Arabidopsis halleri. None of the mobilizing agents used enhanced metal accumulation by T. caerulescens. Between 1998 and 2000, on average across plots where Cd or Zn exceeded allowable limits, T. caerulescens removed 1.3 and 0.3% of the total soil Cd and Zn. In one season when T. caerulescens was grown for 14 months, 21.7 and 4.4% of the total soil Cd and Zn was removed. This was larger than values found when T. caerulescens was grown for 4 months. A. halleri accumulated similar concentrations of Zn, but lower Cd concentrations than T. caerulescens. The results indicate that metal phytoextraction using T. caerulescens can be used to clean up soils moderately contaminated by Cd. - The hyperaccumulator Thlaspi caerulescens (the Ganges ecotype) is more efficient at phytoextracting Cd than Zn from contaminated soil

  15. Field evaluation of Cd and Zn phytoextraction potential by the hyperaccumulators Thlaspi caerulescens and Arabidopsis halleri

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, S.P. [Agriculture and the Environment Division, Rothamsted Research, Harpenden, Herts AL5 2JQ (United Kingdom)]. E-mail: steve.mcgrath@bbsrc.ac.uk; Lombi, E. [Agriculture and the Environment Division, Rothamsted Research, Harpenden, Herts AL5 2JQ (United Kingdom); Gray, C.W. [Agriculture and the Environment Division, Rothamsted Research, Harpenden, Herts AL5 2JQ (United Kingdom); Caille, N. [Agriculture and the Environment Division, Rothamsted Research, Harpenden, Herts AL5 2JQ (United Kingdom); Dunham, S.J. [Agriculture and the Environment Division, Rothamsted Research, Harpenden, Herts AL5 2JQ (United Kingdom); Zhao, F.J. [Agriculture and the Environment Division, Rothamsted Research, Harpenden, Herts AL5 2JQ (United Kingdom)

    2006-05-15

    Field trials were undertaken to investigate the effect of the application of metal mobilizing agents, different sowing strategies and length of growing season on the extraction of Cd and Zn from soils by Thlaspi caerulescens and Arabidopsis halleri. None of the mobilizing agents used enhanced metal accumulation by T. caerulescens. Between 1998 and 2000, on average across plots where Cd or Zn exceeded allowable limits, T. caerulescens removed 1.3 and 0.3% of the total soil Cd and Zn. In one season when T. caerulescens was grown for 14 months, 21.7 and 4.4% of the total soil Cd and Zn was removed. This was larger than values found when T. caerulescens was grown for 4 months. A. halleri accumulated similar concentrations of Zn, but lower Cd concentrations than T. caerulescens. The results indicate that metal phytoextraction using T. caerulescens can be used to clean up soils moderately contaminated by Cd. - The hyperaccumulator Thlaspi caerulescens (the Ganges ecotype) is more efficient at phytoextracting Cd than Zn from contaminated soil.

  16. Geology, mineralization, mineral chemistry, and ore-fluid conditions of Irankuh Pb-Zn mining district, south of Isfahan

    Directory of Open Access Journals (Sweden)

    Mohammad Hassan Karimpour

    2017-11-01

    within carbonate host rocks, whereas Fe-rich sphalerite, galena, pyrite, minor chalcopyrite, low Fe-dolomite, quartz, bituminous, ± barite ± calcite are important primary minerals at clastic host rocks. There is positive correlation between Ag and Sb values within galena mineral. Sb/Bi ratio in galena is up to 20, which is an indicator of low temperature deposits (Malakhov, 1968. The Irankuh homogenization temperature (170 to 260 ºC is higher than that of US Mississippi-type deposits (80 to 120 ºC. Based on comparison of Th and Fe and Cd contents in sphalerite from Irankuh and US deposits (Viets et al., 1992, homogenization temperature of deposit has a positive relation with Fe values and a negative relation with Cd contents in sphalerite. Fe content in Irankuh sphalerite has reached up to 5% and Cd value is lower than 2000 ppm. In addition, carbonate hosted rock hydrothermal dolomites that are Fe-rich and ankrite have formed at some places. The evidence shows that Irankuh ore-fluid is Fe-rich. However, clastic hosted rock hydrothermal dolomites are low-Fe due to reaction of Fe and S resulting in pyrite formation. Based on O isotope (16–19 ‰ value from hydrothermal dolomites (Ghazban et al., 1994, ore-fluid has been derived from continental crust. Results Fe-rich sphalerite and dolomite and ankrite are the most important characteristics of Irankuh mining district. Temperature and Fe-rich nature of ore-fluid and mineralogy signatures of Irankuh area can be used for exploration of this type of mineralization in Iran and the world. The Irankuh mining district is MVT type mineralization. Acknowledgements The Research Division of the Ferdowsi University of Mashhad, Iran, supported this study (Project No. 40221.3. Thanks to Bama Co. (especially Mr. Eslami for the collaborations. References Ayati, F., Dehghani, H., Mokhtari, A.R. and Mojtahedzadeh, H., 2013. Geochemistry and mineralogy studies of Gushfil Pb-Zn deposit, Irankuh, Isfahan. Analytical and Numerical Methods

  17. Application of Zn isotopes in environmental impact assessment of Zn–Pb metallurgical industries: A mini review

    International Nuclear Information System (INIS)

    Yin, Nang-Htay; Sivry, Yann; Benedetti, Marc F.; Lens, Piet N.L.; Hullebusch, Eric D. van

    2016-01-01

    Zn and Pb smelters are the major contributors to Zn and Pb emissions among all anthropogenic sources, thus, it is essential to understand Zn isotopic variations within the context of metallurgical industries, as well as its fractionation in different environments impacted by smelting activities. This mini review outlines the current state of knowledge on Zn isotopic fractionation during the high-temperature roasting process in Zn and Pb refineries; δ"6"6Zn values variations in air emissions, slags and effluents from the smelters in comparison to the geogenic Zn isotopic signature of ores formation and weathering. In order to assess the environmental impact of these smelters, the available and measured δ"6"6Zn values are compiled for smelter impacted natural water bodies (groundwater, stream and river water), sediments (lake and reservoir) and soils (peat bog soil, inland soil). Finally, the discussion is extended to the fractionation induced during numerous physicochemical reactions and transformations, i.e. adsorption, precipitation as well as both inorganic and organic surface complexation. - Highlights: • Zn and Pb smelters are the major contributors to Zn emissions among all anthropogenic sources. • Zn isotopic variations in this context has been widely studied over the last 15 years. • Zn isotopic fractionation during the high-temperature roasting process and electroplating process is summarize. • Subsequent δ"6"6Zn values variations in air emissions, slags and effluents from the smelters are compared to the geogenic one. • The usefulness of δ"6"6Zn values to trace environmental impact of these smelters is discussed.

  18. The influence of CdSe and ZnSe nanoparticles on the optical properties of Sm"3"+ ions in lead borate glasses

    International Nuclear Information System (INIS)

    Mallur, Saisudha B.; Heidorn, William D.; Fatokun, Stephen O.; Joshi, Krishna D.; Bista, Sandip S.; Babu, Panakkattu K.

    2017-01-01

    The effect of glass composition and the presence of CdSe/ZnSe nanoparticles (NPs) on the optical absorption and fluorescence of Sm-doped lead borate glasses are studied. Three sets of glass samples xPbO:(99.5-x) B_2O_3:0.5Sm_2O_3, x = 29.5–69.5 mol%, xPbO:(96.5-x) B_2O_3:0.5Sm_2O_3: 3CdSe/ZnSe, x = 36.5, and 56.5 mol% are prepared. NPs are grown by annealing these glasses just below the glass transition temperature. Average size of both types of NPs increases with annealing time; however, CdSe NPs grew to a larger size range (2 to 20 nm) compared to ZnSe NPs (1 to 16 nm). We analyzed the hypersensitive transition, intensity parameters, radiative transition probability, stimulated emission cross section (σ_p), and the area ratio of the electric dipole/magnetic dipole transitions of Sm"3"+. The intensity parameters show a minimum at 11 h annealing for 36.5 mol% and a maximum for the same annealing duration in 56.5 mol% PbO containing CdSe NPs. The σ_p for 56.5 mol% of PbO with CdSe NPs is found to be a maximum when the average NP size is around 14 nm. ZnSe NPs containing glasses also show significant changes in σ_p when the average particle size is ~16 nm, for 36.5 mol% PbO. Our results suggest that the optical properties of Sm"3"+ in lead borate glasses are sensitive to its electronic environment which can be modified by varying the base glass composition and/or incorporating large NPs of CdSe/ZnSe. The large σ_p values that we observe for some of the glass compositions make them attractive materials for photonic devices and photovoltaic applications.

  19. The influence of CdSe and ZnSe nanoparticles on the optical properties of Sm{sup 3+} ions in lead borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Mallur, Saisudha B.; Heidorn, William D.; Fatokun, Stephen O.; Joshi, Krishna D.; Bista, Sandip S.; Babu, Panakkattu K., E-mail: PK-Babu@wiu.edu [Western Illinois University, Department of Physics (United States)

    2017-03-15

    The effect of glass composition and the presence of CdSe/ZnSe nanoparticles (NPs) on the optical absorption and fluorescence of Sm-doped lead borate glasses are studied. Three sets of glass samples xPbO:(99.5-x) B{sub 2}O{sub 3}:0.5Sm{sub 2}O{sub 3}, x = 29.5–69.5 mol%, xPbO:(96.5-x) B{sub 2}O{sub 3}:0.5Sm{sub 2}O{sub 3}: 3CdSe/ZnSe, x = 36.5, and 56.5 mol% are prepared. NPs are grown by annealing these glasses just below the glass transition temperature. Average size of both types of NPs increases with annealing time; however, CdSe NPs grew to a larger size range (2 to 20 nm) compared to ZnSe NPs (1 to 16 nm). We analyzed the hypersensitive transition, intensity parameters, radiative transition probability, stimulated emission cross section (σ{sub p}), and the area ratio of the electric dipole/magnetic dipole transitions of Sm{sup 3+}. The intensity parameters show a minimum at 11 h annealing for 36.5 mol% and a maximum for the same annealing duration in 56.5 mol% PbO containing CdSe NPs. The σ{sub p} for 56.5 mol% of PbO with CdSe NPs is found to be a maximum when the average NP size is around 14 nm. ZnSe NPs containing glasses also show significant changes in σ{sub p} when the average particle size is ~16 nm, for 36.5 mol% PbO. Our results suggest that the optical properties of Sm{sup 3+} in lead borate glasses are sensitive to its electronic environment which can be modified by varying the base glass composition and/or incorporating large NPs of CdSe/ZnSe. The large σ{sub p} values that we observe for some of the glass compositions make them attractive materials for photonic devices and photovoltaic applications.

  20. Thermodynamics of Pb(ii) and Zn(ii) binding to MT-3, a neurologically important metallothionein.

    Science.gov (United States)

    Carpenter, M C; Shami Shah, A; DeSilva, S; Gleaton, A; Su, A; Goundie, B; Croteau, M L; Stevenson, M J; Wilcox, D E; Austin, R N

    2016-06-01

    Isothermal titration calorimetry (ITC) was used to quantify the thermodynamics of Pb(2+) and Zn(2+) binding to metallothionein-3 (MT-3). Pb(2+) binds to zinc-replete Zn7MT-3 displacing each zinc ion with a similar change in free energy (ΔG) and enthalpy (ΔH). EDTA chelation measurements of Zn7MT-3 and Pb7MT-3 reveal that both metal ions are extracted in a tri-phasic process, indicating that they bind to the protein in three populations with different binding thermodynamics. Metal binding is entropically favoured, with an enthalpic penalty that reflects the enthalpic cost of cysteine deprotonation accompanying thiolate ligation of the metal ions. These data indicate that Pb(2+) binding to both apo MT-3 and Zn7MT-3 is thermodynamically favourable, and implicate MT-3 in neuronal lead biochemistry.

  1. TiO2 flower-like nanostructures decorated with CdS/PbS nanoparticles

    International Nuclear Information System (INIS)

    Trenczek-Zajac, Anita; Kusior, Anna; Lacz, Agnieszka; Radecka, Marta; Zakrzewska, Katarzyna

    2014-01-01

    Highlights: • TiO 2 flower-like nanostructures were prepared with the use of Ti foil and 30% H 2 O 2 . • QDs of CdS and PbS were deposited using the SILAR method. • The SILAR method makes it possible to control the size of QDs. • Band gap energy of CdS was found to be 2.35 eV. • Sensitization of TiO 2 with CdS or PbS improves the photoelectrochemical properties. - Abstract: Flower-like nanostructures of TiO 2 were prepared by immersing Ti foil in 30% H 2 O 2 at 80 °C for times varying from 15 to 240 min. Upon annealing at 450 °C in an Ar atmosphere, the received amorphous samples crystallized in an anatase structure with rutile as a minority phase. SEM images revealed that partially formed flowers were present at the surface of the prepared samples as early as after 15 min of immersion. The size of the individual flowers increased from 400–800 nm after 15 min of reaction to 2.5–6.0 μm after 240 min. It was also found that surface is very rough and surface development is considerable. After 45 min of immersion, the nanoflowers were sensitized with CdS and PbS quantum dots (QDs-CdS/QDs-PbS) deposited using the SILAR method from water- and methanol-based precursor solutions at different concentrations (0.001–0.1 M). QDs-CdS crystallized in the hawleyite structure, while QDs-PbS in the galena form. SEM analysis showed the tendency of quantum dots to agglomerate at high concentrations of the precursor in water-based solutions. QDs obtained from methanol-based solutions were uniformly distributed. The produced QDs-PbS were smaller than QDs-CdS. Based on the optical reflectance spectra, the band-gap energies of TiO 2 nanostructures with and without QDs were calculated to be 3.32 eV for flower-like TiO 2 nanostructures and 2.35 eV for QDs-CdS. The photoelectrochemical behaviour of nanoflowers was found to improve significantly after the deposition of QDs-CdS

  2. Photobrightening of CdSe/ZnS/TOPO nanocrystals

    International Nuclear Information System (INIS)

    Oda, Masaru; Tsukamoto, Junpei; Hasegawa, Atsushi; Iwami, Noriya; Nishiura, Ken; Hagiwara, Izumi; Ando, Naohisa; Horiuchi, Hiromi; Tani, Toshiro

    2007-01-01

    We have investigated photobrightening effects of photoluminescence (PL) from CdSe/ZnS/TOPO nanocrystals (NCs) in ambient nitrogen gas saturated with water molecules (H 2 O/N 2 ). The PL intensities from NC ensemble samples increase more than twice after 1200-s irradiation of cw light. These increases mostly recover to their previous values under continuous light irradiation when we evacuate the H 2 O/N 2 atmosphere. These results indicate that the adsorption of H 2 O molecules onto NC surfaces provides some functions as to restore almost reversibly the PL-quenching defects or trap sites on or near the NC surfaces. To elucidate the mechanism of this restoring function microscopically, we have also measured time evolution of PL intensity profiles from single NCs both in H 2 O/N 2 and in vacuum. While blinking behaviors of the PL intensity being observed in both environments, we have found significant increase of PL on-times in case of single NC observations in the H 2 O/N 2 compared with those in vacuum. As for the blinking off-times, it is for the moment associated with the occasional events of carrier captures at the trap sites on or near the NC surfaces. Thus, we propose the photo-adsorption of H 2 O molecules inactivates these trap sites and decreases the occurrence of the capturing events, which in turn increase PL on-times and eventually provide the photobrightenings

  3. Lasing in ZnO and CdS nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Thielmann, Andreas; Geburt, Sebastian; Kozlik, Michael; Kuehnel, Julian; Borschel, Christian; Ronning, Carsten [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, 07743 Jena (Germany)

    2011-07-01

    The development of nanoscaled semiconductor lasers could be the key resolution to the still persistent size mismatch between integrated microelectronic devices and semiconductor optoelectronic devices. Semiconductor nanowires offer an elegant path to the development of nanoscaled lasers as their geometry with two planar end facets naturally combines a fiber-like waveguide with an optical resonator. The possible stimulation of the material's emission processes enables lasing of resonant optical modes. ZnO and CdS nanowires of different aspect ratios have been synthesized via the VLS mechanism and were characterized by SEM, EDX and ensemble PL measurements. Power dependent PL measurements on single nanowires excited with pulsed laser light at 355 nm have been performed between 10 K and room temperature and were set in correlation to the nanowires' respective morphology. Sharp emission lines which show characteristics of Fabry-Perot modes could be observed above a power threshold. The measured power dependencies reveal amplified stimulated emission and lasing at high excitation densities.

  4. Stability assessment on a 3% bilayer PbS/ZnO quantum dot heterojunction solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Luther, Joseph M.; Lloyd, Matthew T.; Beard, Matthew C. [National Renewable Energy Laboratory, Golden, CO (United States); Gao, Jianbo [National Renewable Energy Laboratory, Golden, CO (United States); University of Toledo, Toledo, OH (United States); Semonin, Octavi E.; Nozik, Arthur J. [National Renewable Energy Laboratory, Golden, CO (United States); University of Colorado, Boulder, CO (United States)

    2010-09-01

    We provide the first NREL-certified efficiency measurement on an all-inorganic, solution-processed, nanocrystal solar cell. The 3% efficient device is composed of ZnO nanocrystals and 1.3 eV PbS quantum dots with gold as the top contact. This configuration yields a stable device, retaining 95% of the starting efficiency after a 1000-hour light soak in air without encapsulation. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  5. XPS-and-DFT analyses of the Pb 4f — Zn 3s and Pb 5d — O 2s overlapped ambiguity contributions to the final electronic structure of bulk and thin-film Pb-modulated zincite

    Energy Technology Data Exchange (ETDEWEB)

    Zatsepin, D.A. [M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620990 Yekaterinburg (Russian Federation); Institute of Physics and Technology, Ural Federal University, 620002 Yekaterinburg (Russian Federation); Boukhvalov, D.W., E-mail: danil@hanyang.ac.kr [Department of Chemistry, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Theoretical Physics and Applied Mathematics Department, Ural Federal University,Mira Street 19, 620002 Yekaterinburg (Russian Federation); Gavrilov, N.V. [Institute of Electrophysics, Russian Academy of Sciences, Ural Branch, 620990 Yekaterinburg (Russian Federation); Kurmaev, E.Z. [M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620990 Yekaterinburg (Russian Federation); Institute of Physics and Technology, Ural Federal University, 620002 Yekaterinburg (Russian Federation); Zatsepin, A.F. [Institute of Physics and Technology, Ural Federal University, 620002 Yekaterinburg (Russian Federation); Cui, L. [Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055 (China); Shur, V. Ya.; Esin, A.A. [Institute of Natural Sciences, Ural Federal University, 51 Lenin Ave, 620000 Yekaterinburg (Russian Federation)

    2017-05-31

    Highlights: • Two modes of ZnO:Pb in the bulk and surface morphologies were established: the high- and low-interaction. • It was shown the ambiguity contribution of Pb 4f − Zn 3s and Pb 5d − O 2s states into final electronic structure. • The main type of defects is PbO-like with some PbO{sub 2}-like contributions. • An applied wurzite-like structural model well agrees with experimental data obtained for zincite. - Abstract: The electronic structures of zincite Pb-modulated bulk and thin-films were studied via X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) techniques. Both XPS data and DFT-calculations allowed the derivation of two different Pb-embedding scenarios into the ZnO-hosts. These included the high-interaction mode of Pb-impurity with initial zinc-oxygen host-lattice for the bulk morphology, accompanied with low Pb-metal losses; and the low-interaction mode for thin-films, where there was intake of Pb-impurities into the hollows of the surface. Despite dissimilar mechanisms of Pb-impurity accumulation and distribution in the bulk and thin-films zincite host-matrices, the strong Pb 4f — Zn 3s and Pb 5d — O 2s overlapped ambiguity contribution to the appropriate core-level structure and valence bands was established by XPS analysis and reproduced with the help of DFT-calculations. It was shown that the microscopic structure of the embedded lead-impurity played a crucial role in the Pb ion-beam stimulated synthesis of secondary lead-oxygen phases via large-area defect fabrication, and the difference among zincite and wurzite polymorphs played almost no role in this case.

  6. CdCl2 passivation of polycrystalline CdMgTe and CdZnTe absorbers for tandem photovoltaic cells

    Science.gov (United States)

    Swanson, Drew E.; Reich, Carey; Abbas, Ali; Shimpi, Tushar; Liu, Hanxiao; Ponce, Fernando A.; Walls, John M.; Zhang, Yong-Hang; Metzger, Wyatt K.; Sampath, W. S.; Holman, Zachary C.

    2018-05-01

    As single-junction silicon solar cells approach their theoretical limits, tandems provide the primary path to higher efficiencies. CdTe alloys can be tuned with magnesium (CdMgTe) or zinc (CdZnTe) for ideal tandem pairing with silicon. A II-VI/Si tandem holds the greatest promise for inexpensive, high-efficiency top cells that can be quickly deployed in the market using existing polycrystalline CdTe manufacturing lines combined with mature silicon production lines. Currently, all high efficiency polycrystalline CdTe cells require a chloride-based passivation process to passivate grain boundaries and bulk defects. This research examines the rich chemistry and physics that has historically limited performance when extending Cl treatments to polycrystalline 1.7-eV CdMgTe and CdZnTe absorbers. A combination of transmittance, quantum efficiency, photoluminescence, transmission electron microscopy, and energy-dispersive X-ray spectroscopy clearly reveals that during passivation, Mg segregates and out-diffuses, initially at the grain boundaries but eventually throughout the bulk. CdZnTe exhibits similar Zn segregation behavior; however, the onset and progression is localized to the back of the device. After passivation, CdMgTe and CdZnTe can render a layer that is reduced to predominantly CdTe electro-optical behavior. Contact instabilities caused by inter-diffusion between the layers create additional complications. The results outline critical issues and paths for these materials to be successfully implemented in Si-based tandems and other applications.

  7. Fast and direct analysis of Cr, Cd and Pb in brown sugar by GF AAS.

    Science.gov (United States)

    Dos Santos, Jeferson M; Quináia, Sueli P; Felsner, Maria L

    2018-09-15

    A simple and fast analytical method for the determination of Cr, Pb and Cd in brown sugar by GF AAS using slurry sampling was developed and in house validated for the first time. Analytical curves were prepared by external standardization for Cr, and by matrix simulation for Pb and Cd and they were linear. Low limits of quantification for Cr (32.8 ng g -1 ), Pb (49.3 ng g -1 ) and Cd (4.5 ng g -1 ) were found. Repeatability and intermediate precision estimates (brown sugar samples ranged from <32.8 to 160 ng g -1 for Cr, from <49.3 to 211.0 ng g -1 for Pb and from <4.5 to 7.0 ng g -1 for Cd and they may be assigned to anthropogenic activities and the adoption of inadequate practices of production and processing. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. 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

    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...

  9. 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.

    An attempt has been made to present a picture of the distribution of toxic trace elements Cd and Pb in the Northern Arabian Sea by applying an improved analytical technique for the detection of dissolved forms of the metals at nanogram levels...

  10. 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.

  11. Batch adsorption of heavy metals (Cu, Pb, Fe, Cr and Cd) from ...

    African Journals Online (AJOL)

    cinthia

    This study was carried out to evaluate the efficiency of metals (Cu, Fe, Pb, Cr and Cd) removal from mixed metal ions solution using coconut husk as adsorbent. The effects of varying contact time, initial metal ion concentration, adsorbent dose and pH on adsorption process of these metals were studied using synthetically ...

  12. Ecological effects of some heavy metals (Cd, Pb, Hg, Cr) pollution of ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-06-17

    Jun 17, 2008 ... Accumulation of heavy metals (Cd, Pb, Hg, Cr) in water and plankton of Sarıyar Dam Lake (SDR) was seasonally ... human impacts in protected areas with the aim of .... (1999), heavy metals toxicity is affected by temperature,.

  13. Bioremediation of Zn, Cu, Mg and Pb in Fresh Domestic Sewage by Brevibacterium sp

    International Nuclear Information System (INIS)

    Ojoawo, S. O.; Rao, C. V.; Goveas, L. C.

    2016-01-01

    The study applied an isolated Brevibacterium sp. (MTCC 10313) for bioremediation of Zn, Cu, Mg and Pb in domestic sewage. Batch culture experiments were performed on both the fresh and stale sewage samples with glucose supplementation of 1-8g/l. Nutrient broth medium was prepared, sterilized and p H adjusted to 6.5-6.8. 1% of the Brevibacteria sp. stock was inoculated into the broth and maintained at 370C for 24 hours in shaker incubator at 120 rpm. Another 1% of fresh grown sub-culture of broth was inoculated into supplemented and sterilized samples. Optical Density was taken at 600nm, growth monitored over 12 days, cultured samples denatured with TCA and centrifuged, supernatants filtered and analyzed with AAS, Settled pellets oven dried, subjected to SEM analysis for morphology and constituents determination. Fresh sewage samples permitted bacterial growth and facilitated bioremediation of Zn, Cu and Mg through metal uptake and bioabsoption by Brevibacteria sp. This effectively reduced concentration of heavy metals, with treatment efficiency order Cu>Zn>Mg, and respective removal percentages of 77, 63 and 55. The optimum glucose concentration for effective bioremediation found as 2g/l for Zn and Cu, and 8g/l for Mg. Pb was resistant to bioremediation with Brevibacteria sp. Stale sewage produced inhibitory substances preventing adequate growth of bacterium with no bioremediation. Bioremediation with Brevibacteria sp. is found effective in removal of micro-units of Zn, Cu and Mg from domestic sewage. As a readily available low-cost agent, it is recommended for large- scale application on those metals while Pb should be further subjected to advanced treatments.

  14. On the response of alloyed ZnCdSeS quantum dot films

    Directory of Open Access Journals (Sweden)

    I. Valais

    Full Text Available The aim of this work was to prepare composite ZnCdSeS quantum dot (QD flexible films and to examine their optical properties under ultraviolet excitation. PMMA/QD ZnCdSeS composite films, with emission covering the visual spectrum (480–630 nm were prepared with concentrations 10 mg/mL and 20 mg/mL by homogenously diluting dry powder QD samples in toluene and subsequently mixing with a PMMA/MMA polymer solution to the final ZnCdSeS/Toluene mixture. Scanning electron microscopy (SEM images of the produced films were obtained. The ZnCdSeS films were excited by ultraviolet light of varying intensities and the spectral matching with various optical detectors was estimated.

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

    Indian Academy of Sciences (India)

    Abstract. Zn- and Cu-doped CdS thin films were deposited onto glass substrates by the chemical bath technique. ... Cadmium sulfide; chemical bath deposition; doping; optical window. 1. ..... at low temperature (10 K), finding similar trends than.

  16. Performance simulation and structure design of Binode CdZnTe gamma-ray detector

    International Nuclear Information System (INIS)

    Niu Libo; Li Yulan; Fu Jianqiang; Jiang Hao; Zhang Lan; He Bin; Li Yuanjing

    2014-01-01

    A new electrode structure CdZnTe (Cadmium Zinc Telluride) detector named Binode CdZnTe has been pro- posed in this paper. Together with the softwares of MAXWELL, GEANT4, and ROOT, the charge collection process and its gamma spectrum of the detector have been simulated and the detector structure has been optimized. In order to improve its performance further, Compton scattering effect correction has been used. The simulation results demonstrate that with refined design and Compton scattering effect correction, Binode CdZnTe detectors is capable of achieving 3.92% FWHM at 122 keV, and 1.27% FWHM at 662 keV. Com- pared with other single-polarity (electron-only) detector configurations, Binode CdZnTe detector offers a cost effective and simple structure alternative with comparable energy resolution. (authors)

  17. Photoemission investigation of the ZnSe/CdTe heterojunction band discontinuity

    International Nuclear Information System (INIS)

    Nelson, A.J.

    1995-01-01

    Synchrotron radiation soft x-ray photoemission spectroscopy and reflection high-energy electron diffraction were used to investigate the structural and electronic properties at the ZnSe/CdTe(100) heterojunction interface. ZnSe overlayers were sequentially grown in steps on p-type CdTe(100) single crystals at 200 degree C. In situ photoemission measurements were acquired after each growth in order to observe changes in the valence band electronic structure as well as changes in the Cd 4d, Zn 3d, and Te 4d core lines. The results were used to correlate the interfacial chemistry with the electronic structure and to directly determine the ZnSe/CdTe heterojunction valence band discontinuity and the consequent heterojunction band diagram. Results of these measurements reveal that the valence band offset is ΔE v =0.20 eV. copyright 1995 American Institute of Physics

  18. Evaluation of potential of adsorption of U, Th, Pb, Zn and Ni by coconut fibers

    International Nuclear Information System (INIS)

    Monteiro, Raquel Almeida

    2009-01-01

    The residual biomass from agricultural activities has been evaluated as biosorbent for metals and organic composts from aqueous solutions, because of its adsorptive properties, low cost, abundance and to be a renewable resource. In this work, the efficiency of coir pith as biosorbent for the removal of U, Th, Pb, Zn e Ni ions from the aqueous solutions is presented. The coir pith is a by-product of the harvest of the coconut, a renewable natural source. The study was conducted by batch method. The influence of pH from 1 to 8, the dosage of the coir pith and the equilibrium time were studied. The adsorption of metal ions increased with the increase of pH and the dose. The Langmuir and Freundlich models were applied to describe the adsorption equilibrium isotherm. The kinetic process was studied using the pseudo-first order and pseudo-second order models. The Gibbs free energy was calculated. In the concentration range of 100 mg.L -1 - 500 mg.L -1 , the adsorption process was described better by the Langmuir equation for Pb 2+ and Zn 2+ ions and the Freundlich equation for UO 2 2 + , Th 4+ and Ni 2+ ions, and represented by the pseudo-second order model. The biosorption process for removal of metal ions from the solutions was considered spontaneous. The results were promising, showing perspectives of application of coir pith as biosorbent of U, Th, Pb, Zn and Ni ions in wastewater treatment processes. (author)

  19. Study of Zn-Pb ore tailings and their potential in cement technology

    Science.gov (United States)

    Nouairi, J.; Hajjaji, W.; Costa, C. S.; Senff, L.; Patinha, C.; Ferreira da Silva, E.; Labrincha, J. A.; Rocha, F.; Medhioub, M.

    2018-03-01

    This paper describes the synthesis of sulfobelite clinkers incorporating mining rejects. The targeted Zn-Pb tailing wastes generated in the diapiric zone (NW Tunisia) were tested in clinker/cement compositions to ensure the inertization of existing hazardous heavy metals. Mineralogical composition of the two selected samples revealed calcite, dolomite, quartz, kaolinite, galena, pyrite and gypsum as crystalline phases. Vertical distributions of dominant heavy metals (Pb, Zn and Cu) in soil profiles show enrichment in the surface layers and decrease towards the depth. In sintered clinkers powders, the presence of the targeted crystalline phases (trialuminate sulphate (C4A3Š), belite (C2S), and ferrite (C4AF)) are in the predicted desirable amounts. Heat flow generated during the hydration of different cement pastes showed a slower reaction for clinkers with higher amounts of C4A3Š or constituted by coarser particles. After 28 days curing, the best mechanical resistance (24.34 MPa under compression) was obtained for the clinker calcined at 1350 °C and showing a suitable particle size distribution. Concerning heavy metals, immobilisation of 75-85% of Pb, Zn and Cu was assessed in the mortars formulated with the produced clinker/cement, posing no hazardous risks to the environment.

  20. Fractal structures in two-metal electrodeposition systems I: Pb and Zn

    International Nuclear Information System (INIS)

    Nakouzi, Elias; Sultan, Rabih

    2011-01-01

    Pattern formation in two-metal electrochemical deposition has been scarcely explored in the chemical literature. In this paper, we report new experiments on zinc-lead fractal co-deposition. Electrodeposits are grown in special cells at a fixed large value of the zinc ion concentration, while that of the lead ion is increased gradually. A very wide diversity of morphologies are obtained and classified. Most of the deposited domains are almost exclusively Pb or Zn. But certain regions originating at the base cathode, ranging from a short grass alley to dense, grown-up bushes or shrubs, manifest a combined Pb-Zn composition. Composition is determined using scanning electron microscopy/energy dispersive x ray measurements as well atomic absorption spectroscopy. Pb domains are characterized by shiny leaf-like and dense deposits as well as flowers with round, balloon-like corollas. The Zn zones display a greater variety of morphologies such as thick trunks and thin and fine branching, in addition to minute ''cigar flower'' structures. The various morphologies are analyzed and classified from the viewpoint of fractal nature, characterized by the box-count fractal dimension. Finally, macroscopic spatial alternation between two different characteristic morphologies is observed under certain conditions.

  1. 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.

  2. HYDROTALSIT Zn-Al-EDTA SEBAGAI ADSORBEN UNTUK POLUTAN ION Pb(II DI LINGKUNGAN Zn-Al-EDTA Hydrotalcite as Adsorbent for Pb(II Ion Pollutant in The Environment

    Directory of Open Access Journals (Sweden)

    Roto Roto

    2015-07-01

    Full Text Available ABSTRAK Polusi ion Pb(II di dalam lingkungan perairan cenderung naik seiring peningkatan jumlah industri smelter dan daur ulang aki bekas. Penelitian ini bertujuan untuk menguji kemampuan hidrotalsit Zn-Al-EDTA sebagai adsorben ion Pb(II dalam air secara mendalam. Hidrotalsit Zn-Al-NO3 disintesis dengan metode kopresipitasi dan hidrotermal pada temperatur 100 °C selama 15 jam. Hidrotalsit Zn-Al-EDTA diperoleh dengan penukaran ion. Keasaman larutan, kinetika dan kapasitas adsorpsi diteliti. Hidrotalsit Zn-Al-EDTA memiliki d003 sebesar 14,52 Å sementara Zn-Al-NO3 sebesar 8,90 Å. Spektra FTIR menunjukkan keberadaan serapan gugus C=O pada bilangan gelombang 1684,77 cm-1. Kondisi optimum adsorpsi ion Pb(II terjadi pada pH 4, waktu kontak 60 menit dan kapasitas adsorpsi diperoleh 2,07 mg/g pada konsentrasi awal 10 mg/L dengan berat adsorben 0,100 g. Adsorpsi ion Pb(II oleh hidrotalsit Zn-Al-EDTA mengikuti reaksi pseudo orde dua dengan tetapan laju adsorpsi sebesar 8,90 g mmol-1min-1. Adsorpsi ion Pb(II oleh Zn-Al-EDTA terjadi karena  pembentukan khelat Pb-EDTA di dalam struktur hidrotalsit. Hasil ini diharapkan mampu memberikan kontribusi yang lebih luas di dalam pengendalian konsentrasi Pb(II di lingkungan. ABSTRACT Polution by Pb(II ion in the water environment tends to increase due the increase in the number of lead smelter and lead acid battery recycling industries. This work aims at studying in details the ability of Zn-Al-EDTA hydrotalcite as adsorbent for Pb(II ion in the environment. The Zn-Al-NO3 hydrotalcite was synthesized first by coprecipitation method followed by hydrothermal treatment at 100 °C for 15 h. The Zn-Al-EDTA hydrotalcite was later obtained by ion exchange process. The solution pH, kinetics and adsorption capacity were studied. The XRD data showed that Zn-Al-EDTA and Zn-Al-NO3 hydrotalcites have d003 of 14.52 and 8.90 Å, respectively. The FTIR spectra suggested that C=O group was observed with absorption band at 1684

  3. Characterization of CdTe and (CdZn)Te detectors with different metal contacts

    Science.gov (United States)

    Pekárek, J.; Belas, E.; Grill, R.; Uxa, Å.; James, R. B.

    2013-09-01

    In the present work we studied an influence of different types of surface etching and surface passivation of high resistivity CdZnTe-based semiconductor detector material. The aim was to find the optimal conditions to improve the properties of metal-semiconductor contact. The main effort was to reduce the leakage current and thus get better X-ray and gamma-ray spectrum, i.e. to create a detector operating at room temperature based on this semiconductor material with sufficient energy resolution and the maximum charge collection efficiency. Individual surface treatments were characterized by I-V characteristics, spectral analysis and by determination of the profile of the internal electric field.

  4. A Case Study of Landfill Leachate Using Coal Bottom Ash for the Removal of Cd2+, Zn2+ and Ni2+

    Directory of Open Access Journals (Sweden)

    Julia Ayala

    2016-11-01

    Full Text Available The removal of Cd2+, Zn2+ and Ni2+ by coal bottom ash has been investigated. In single metal system, metal uptake was studied in batch adsorption experiments as a function of pH (2–3, contact time (5–180 min, initial metal concentration (50–400 mg/L, adsorbent concentration (5–40 g/L, particle size, and ionic strength (0–1 M NaCl. Removal percentages of metals ions increased with increasing pH and dosage. Removal efficiency at lower concentrations was greater than at higher values. The maximum amount of metal ion adsorbed in milligrams per gram was 35.4, 35.1 and 34.6 mg/g for Zn2+, Cd2+ and Ni2+, respectively, starting out from an initial solution at pH 3. Simultaneous removal of Zn2+, Cd2+ and Ni2+ ions from ternary systems was also investigated and compared with that from single systems. Cd2+ uptake was significantly affected by the presence of competing ions at pH 2. The results obtained in the tests with landfill leachate showed that bottom ash is effective in simultaneously removing several heavy metals such as Ni, Zn, Cd, As, Mn, Cu, Co, Se, Hg, Ag, and Pb.

  5. Electronic structure and optical properties in ZnO:M(Co, Cd)

    International Nuclear Information System (INIS)

    Palacios, P.; Aguilera, I.; Wahnon, P.

    2010-01-01

    ZnO doped with some transitions metals (ZnO:M) has several significant potential application. ZnO:Co is proposed to be used in advanced spintronic devices due to its high Curie temperature and large magnetic moments per transition metal. ZnO:Cd has potential applications in short-wavelength optoelectronic devices. This work focuses on an ab-initio study of the electronic and optical properties of ZnO:M doped with Co, and Cd. Theoretical calculations have been done with different computational codes, using the density functional theory (DFT) at the GGA and GGA+U level. The latter introduces a Hubbard term correction in the 'd' levels of the Zn and Co. We used different supercells in order to have different realistic dilution levels which can be achieved in experiments. Doping effects on the features of the optical absorption are also studied and analysed in this work.

  6. Synthesis and Structural Studies of Nanocrystalline Cd 0.3 Zn 0.7 Fe ...

    African Journals Online (AJOL)

    The precursor was characterized by hydrazine and metal analyses, infrared spectral analysis and thermogravimetric analysis. Under appropriate annealing conditions, Cd0.3Zn0.7Fe2(cin)3(N2H4)2 yielded Cd0.3Zn0.7Fe2O4 nanoparticles, which were characterized for their size and structure using X-Ray Diffraction (XRD), ...

  7. Photoluminescent enhancement of CdSe/Cd(1-x) Zn(x)S quantum dots by hexadecylamine at room temperature.

    Science.gov (United States)

    Yang, Jie; Yang, Ping

    2012-09-01

    CdSe/Cd(1-x) Zn(x)S core/shell quantum dots (QDs) were fabricated in 1-octadecene via a two step synthesis. CdSe cores were first prepared using CdO, trioctylphosphine (TOP) selenium, and stearic acid. Subsquently, a Cd(1-x) Zn(x)S shell coating was carried out using zinc acetate dihydrate, cadmium acetate dihydrate, TOPS, and hexadecylamine (HDA) starting materials in the friendly organic system under relatively low temperature. The absorption and photoluminescence (PL) spectra have a significant red shift after the coverage of Cd(1-x)Zn(x)S shell on CdSe cores. The X-ray diffraction analysis of samples confirmed the formation of core/shell structure. The PL quantum yields (QYs) of CdSe/Cd(1-x)Zn(x)S QDs were improved gradually with time at room temperature. This is ascribed to the surface passivation of HDA to the QDs during store. This phenomenon was confirmed by the Fourier transform infrared spectrum of samples. Namely, HDA does not capped on the surface of as-prepared QDs, in which a low PL QYs was observed (less than 10%). Being storing for certain time, HDA attached to the surface of the QDs, in which the PL QYs increased (up to 31%) and the full width at half maximum of PL spectra decreased. Moreover, the fluorescence decay curve of the core/shell QDs is closer to a biexponential decay profile and has a longer average PL lifetime. The variation of average PL lifetime also indicated the influence of HDA during store.

  8. Potential use of lime combined with additives on (im)mobilization and phytoavailability of heavy metals from Pb/Zn smelter contaminated soils.

    Science.gov (United States)

    Hussain Lahori, Altaf; Zhang, Zengqiang; Guo, Zhanyu; Mahar, Amanullah; Li, Ronghua; Kumar Awasthi, Mukesh; Ali Sial, Tanveer; Kumbhar, Farhana; Wang, Ping; Shen, Feng; Zhao, Junchao; Huang, Hui

    2017-11-01

    This explorative study was aimed to assess the efficiency of lime alone and in combined with additives to immobilize Pb, Cd, Cu and Zn in soil and reduce their phytoavailability for plant. A greenhouse pot experiment was performed by using low and heavily contaminated top soils viz. Tongguan contaminated (TG-C); Fengxian heavily contaminated (FX-HC) and Fengxian low contaminated (FX-LC). The contaminated soils were treated with lime (L) alone and in combined with Ca-bentonite (CB), Tobacco biochar (TB) and Zeolite (Z) at 1% and cultivated by Chinese cabbage (Brassica campestris L). Results revealed that all amendments (plime alone and in combined with additives were drastically decreased the dry biomass yield of Brassica campestris L. as compared with control. Thus, these feasible amendments potentially maximum reduced the uptake by plant shoots upto Pb 53.47 and Zn 67.93% with L+Z and L+TB in FX-LC soil, while Cd 68.58 and Cu 60.29% with L+TB, L+CB in TG-C soil but Cu uptake in plant shoot was observed 27.26% and 30.17% amended with L+TB and L+Z in FX-HC and FX-LC soils. On the other hand, these amendments were effectively reduced the potentially toxic metals (PTMs) in roots upto Pb77.77% L alone in FX-HC, Cd 96.76% with L+TB in TG-C, while, Cu 66.70 and Zn 60.18% with L+Z in FX-LC. Meanwhile, all amendments were responsible for increasing soil pH and CEC but decreased soils EC level. Based on this result, these feasible soil amendments were recommended for long term-study under field condition to see the response of another hyper accumulator crop. Copyright © 2017. Published by Elsevier Inc.

  9. 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.

  10. Wave Function Engineering in CdSe/PbS Core/Shell Quantum Dots.

    Science.gov (United States)

    Wieliczka, Brian M; Kaledin, Alexey L; Buhro, William E; Loomis, Richard A

    2018-05-25

    The synthesis of epitaxial CdSe/PbS core/shell quantum dots (QDs) is reported. The PbS shell grows in a rock salt structure on the zinc blende CdSe core, thereby creating a crystal structure mismatch through additive growth. Absorption and photoluminescence (PL) band edge features shift to lower energies with increasing shell thickness, but remain above the CdSe bulk band gap. Nevertheless, the profiles of the absorption spectra vary with shell growth, indicating that the overlap of the electron and hole wave functions is changing significantly. This leads to over an order of magnitude reduction of absorption near the band gap and a large, tunable energy shift, of up to 550 meV, between the onset of strong absorption and the band edge PL. While the bulk valence and conduction bands adopt an inverse type-I alignment, the observed spectroscopic behavior is consistent with a transition between quasi-type-I and quasi-type-II behavior depending on shell thickness. Three effective mass approximation models support this hypothesis and suggest that the large difference in effective masses between the core and shell results in hole localization in the CdSe core and a delocalization of the electron across the entire QD. These results show the tuning of wave functions and transition energies in CdSe/PbS nanoheterostructures with prospects for use in optoelectronic devices for luminescent solar concentration or multiexciton generation.

  11. Partially decomposed PVP as a surface modification of ZnO, CdO ...

    Indian Academy of Sciences (India)

    2017-06-10

    Jun 10, 2017 ... of oxygen with PVP to capsulate metal oxides during the synthesis. Infrared .... to prepare PVP–CdS nanoparticles [19] and here we extend it to prepare ZnS, .... ZnS by a microwave–hydrothermal method and obtained band.

  12. Synthesis and luminescence properties of (Zn,Cd)S:Ag nanocrystals by hydrothermal method

    International Nuclear Information System (INIS)

    Luo Xixian; Cao Wanghe; Zhou Lixin

    2007-01-01

    ZnS:Ag and (Zn,Cd)S:Ag nanoparticles with particle sizes of about 50 and 150 nm have been prepared by hydrothermal method. The effects of hydrothermal process on the physical and luminescence characteristics are investigated. The photoluminescence intensities of hydrothermal treatment ZnS:Ag samples are 10 times higher than that of non-treated samples after annealing at 800 deg. C

  13. Improved performance of CdSe/CdS/PbS co-sensitized solar cell with double-layered TiO2 films as photoanode

    Science.gov (United States)

    Zhang, Xiaolong; Lin, Yu; Wu, Jihuai; Jing, Jing; Fang, Biaopeng

    2017-07-01

    Improving the photovoltaic performance of CdSe/CdS/PbS co-sensitized double-layered TiO2 solar cells is reported. Double-layered TiO2 films with TiO2 microspheres as the light blocking layers were prepared. PbS, CdS and CdSe quantum dots (QDs) were assembled onto TiO2 photoanodes by simple successive ionic layer absorption and reaction (SILAR) to fabricate CdSe/CdS/PbS co-sensitized solar cells. An improved power conversion efficiency (PCE) of 5.11% was achieved for CdSe/CdS/PbS co-sensitized solar cells at one sun illumination (AM 1.5 G, 100 mW cm-2), which had an improvement of 22.6% over that of the CdSe/CdS co-sensitized solar cells (4.17%). This enhancement is mainly attributed to their better ability of the absorption of solar light with the existence of PbS QDs, the reduction of charge recombination of the excited electron and longer lifetime of electrons, which have been proved with the photovoltaic studies and electrochemical impedance spectroscopy (EIS).

  14. Facile preparation and characterization of ZnCdS nanocrystals for interfacial applications in photovoltaic devices.

    Science.gov (United States)

    Duan, Chenghao; Luo, Weining; Jiu, Tonggang; Li, Jiangsheng; Wang, Yao; Lu, Fushen

    2018-02-15

    Recently, ZnCdS nanocrystals (NCs) have attracted intense attention because of their specific optical properties and electrical characteristics. In this paper, a green and facile solution method is reported for the preparation of ZnCdS nanocrystals using dimethylsulfoxide as small molecular ligands. The ZnCdS nanocrystals are used as an interface modification material in the photovoltaic devices. It is found that the modification of ZnCdS on TiO 2 surface not only suppresses the recombination loss of carriers but also reduces the series resistance of TiO 2 /active layer. Consequently, both of the short circuit current (J sc ) and the fill factor (FF) of the solar cells were significantly improved. Power conversion efficiency (PCE) of 7.75% based on TiO 2 /ZnCdS was achieved in contrast to 6.65% of the reference devices based on pure TiO 2 film in organic solar cells. Furthermore, the PCE of perovskite solar cells based on TiO 2 /ZnCdS was observed with 8.3% enhancement compared to that of pure TiO 2 -based ones. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Biosorption of Cd(II) and Zn(II) by nostoc commune: isotherm and kinetics studies

    Energy Technology Data Exchange (ETDEWEB)

    Morsy, Fatthy M. [Faculty of Science, Botany Department, Assiut University, Assiut (Egypt); Hassan, Sedky H.A. [Department of Biological Environment, Kangwon National University, Kangwon-do (Korea, Republic of); Koutb, Mostafa [Faculty of Science, Botany Department, Assiut University, Assiut (Egypt); Umm Al-Qura University, Faculty of Applied Science, Biology Department, Mecca (Saudi Arabia)

    2011-07-15

    In this study, Nostoc commune (cyanobacterium) was used as an inexpensive and efficient biosorbent for Cd(II) and Zn(II) removal from aqueous solutions. The effect of various physicochemical factors on Cd(II) and Zn(II) biosorption such as pH 2.0-7.0, initial metal concentration 0.0-300 mg/L and contact time 0-120 min were studied. Optimum pH for removal of Cd(II) and Zn(II) was 6.0, while the contact time was 30 min at room temperature. The nature of biosorbent and metal ion interaction was evaluated by infrared (IR) technique. IR analysis of bacterial biomass revealed the presence of amino, carboxyl, hydroxyl, and carbonyl groups, which are responsible for biosorption of Cd(II) and Zn (II). The maximum biosorption capacities for Cd(II) and Zn(II) biosorption by N. commune calculated from Langmuir biosorption isotherm were 126.32 and 115.41 mg/g, respectively. The biosorption isotherm for two biosorbents fitted well with Freundlich isotherm than Langmuir model with correlation coefficient (r{sup 2} < 0.99). The biosorption kinetic data were fitted well with the pseudo-second-order kinetic model. Thus, this study indicated that the N. commune is an efficient biosorbent for the removal of Cd(II) and Zn(II) from aqueous solutions. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. The response of metallothionein and malondialdehyde after exclusive and combined Cd/Zn exposure in the crab Sinopotamon henanense.

    Directory of Open Access Journals (Sweden)

    Yingjun Li

    Full Text Available The purpose of this paper is to show the interactions of Cd and Zn in the freshwater crab Sinopotamon henanense through metallothionein (MT and malondialdehyde (MDA level measurements. Laboratory acclimated S.henanense were exposed to Cd (50 µg/L, 100 µg/L, 500 µg/L , and Zn (100 µg/L, 1000 µg/L alone and in combined treatments (100 µg/L Zn+50 µg/L Cd, 100 µg/L Zn+100 µg/L Cd, 100 µg/L Zn+500 µg/L Cd, 1000 µg/L Zn+50 µg/L Cd, 1000 µg/L Zn+100 µg/L Cd, 1000 µg/L Zn+500 µg/L Cd for 7, 14, 21, 28, 35 days. The results demonstrated that the MDA contents increased with exposure time and dose and showed time- and dose-dependence in both gills and hepatopancreas of S.henanense after single Cd exposure, while the changes of MDA levels were not significant with single Zn exposure. The MDA levels decreased when the crabs were exposed to metal mixtures compared to Cd exposure alone, indicating that Zn mediated the cellular toxicity of Cd. MT contents increased after single Cd exposure and also showed a time- and dose-dependence, in a tissue-specific way. Zn showed a limited ability of MT induction both in gills and hepatopancreas of S.henanense. The MT contents represented not a simple addition of single metal exposures but were enhanced at a higher concentration of Zn combined with different Cd concentrations compared to single metal exposure. Whether MT can be used as a biomarker for complex field conditions need to be considered cautiously since different induction patterns of MT were found among single Zn, Cd and combined groups. It is suggested that several biomarkers together as a suite should be used in the monitoring of heavy metal pollution in the aquatic environment.

  17. Corrosion behaviour of boiler tube materials during combustion of fuels containing Zn and Pb

    Energy Technology Data Exchange (ETDEWEB)

    Bankiewicz, D.

    2012-11-01

    Many power plants burning challenging fuels such as waste-derived fuels experience failures of the superheaters and/or increased waterwall corrosion due to aggressive fuel components already at low temperatures. To minimize corrosion problems in waste-fired boilers, the steam temperature is currently kept at a relatively low level which drastically limits power production efficiency. The elements found in deposits of waste and waste-derived fuels burning boilers that are most frequently associated with high-temperature corrosion are: Cl, S, and there are also indications of Br; alkali metals, mainly K and Na, and heavy metals such as Pb and Zn. The low steam pressure and temperature in waste-fired boilers also influence the temperature of the waterwall steel which is nowadays kept in the range of 300 deg C - 400 deg C. Alkali chloride (KCl, NaCl) induced high-temperature corrosion has not been reported to be particularly relevant at such low material temperatures, but the presence of Zn and Pb compounds in the deposits have been found to induce corrosion already in the 300 deg C - 400 deg C temperature range. Upon combustion, Zn and Pb may react with Cl and S to form chlorides and sulphates in the flue gases. These specific heavy metal compounds are of special concern due to the formation of low melting salt mixtures. These low melting, gaseous or solid compounds are entrained in the flue gases and may stick or condense on colder surfaces of furnace walls and superheaters when passing the convective parts of the boiler, thereby forming an aggressive deposit. A deposit rich in heavy metal (Zn, Pb) chlorides and sulphates increases the risk for corrosion which can be additionally enhanced by the presence of a molten phase. The objective of this study was to obtain better insight into high-temperature corrosion induced by Zn and Pb and to estimate the behaviour and resistance of some boiler superheater and waterwall materials in environments rich in those heavy metals

  18. The first report of Pb and Zn accumulation in some native plants from the Peruvian Andes

    Science.gov (United States)

    Bech, Jaume; Duran, Paola; Poma, Wilfredo; Sánchez, Isidoro; Barceló, Juan; Roca, Núria; Boluda, Rafael; Roca-Pérez, Luís.; Poschenrieder, Charlotte

    2010-05-01

    Until recent decades little has been known about the remediation of mining sites using metalophytes in Latin America. Metal mining has helped to create severe and diverse environmental problems. The present study proposed to identify and characterize spontaneously growing heavy metal tolerant plant species in the area around the polimetalic mine in Hualgayoc (Cajamarca, Peru). These species are potentially useful for phytorremediation. Plant and soils from their rhizosphere were sampled and analized for concentration of As, Fe, Mn, Pb and Zn. Translocation Factor (TF) defined the metals concentrations ratio between shoots and root biomass and Shoot Accumulation Factor (SAF) the metal concentration ratio between shoot and soil concentration were determined and used to measure the effectiveness of a plant in concentrating metals into its biomass. The soils were neutral pH (7,4±0,5) with variable content of organic carbon (2,4±1,1) and loam texture: sand (42,9±10,8) and clay (16,7±4,6). According to the total metals, all samples exceeded toxicity thresholds, high Pb (20016 ± 32559 mg•kg-1) and Zn (22512 ± 13056 mg•kg-1) concentrations were detected. High shoot Pb and Zn concentrations were found in Plantaginaceae Plantago orbignyana (6998 and 9617 μg/g); Brassicaceae Lepidium bipinnatifidum (6886 and 5034 mg•kg-1) and Asteraceae Senecio sp (4253 and 3870 mg•kg-1) and Baccharis latifolia (2554 and 1284 mg•kg-1 respectively). The high values of TFs indicates that the plants effectively traslocated metales. Lepidium bipinnatifidum shows the highest TFs values (143 in Pb and 21,5 in Zn). The SAF values were much lower than those reported for other species such as Paspalum sp in the Peruvian copper mine, which may be due to a high top soil Pb and Zn concentrations. These species can surely be considered as interesting for phytoextraction, due not only to its accumulative capacity but also since they showed an elevated transfer factor and grew in the

  19. Identification of Ag-acceptors in $^{111}Ag^{111}Cd$ doped ZnTe and CdTe

    CERN Document Server

    Hamann, J; Deicher, M; Filz, T; Lany, S; Ostheimer, V; Strasser, F; Wolf, H; Wichert, T

    2000-01-01

    Nominally undoped ZnTe and CdTe crystals were implanted with radioactive /sup 111/Ag, which decays to /sup 111/Cd, and investigated by photoluminescence spectroscopy (PL). In ZnTe, the PL lines caused by an acceptor level at 121 meV are observed: the principal bound exciton (PBE) line, the donor-acceptor pair (DAP) band, and the two-hole transition lines. In CdTe, the PBE line and the DAP band that correspond to an acceptor level at 108 meV appear. Since the intensities of all these PL lines decrease in good agreement with the half-life of /sup 111/Ag of 178.8 h, both acceptor levels are concluded to be associated with defects containing a single Ag atom. Therefore, the earlier assignments to substitutional Ag on Zn- and Cd-lattice sites in the respective II-VI semiconductors are confirmed. The assignments in the literature of the S/sub 1/, S /sub 2/, and S/sub 3/ lines in ZnTe and the X/sub 1//sup Ag/, X/sub 2 //sup Ag//C/sub 1//sup Ag/, and C/sub 2//sup Ag/ lines in CdTe to Ag- related defect complexes are ...

  20. Subcellular compartmentalization of Cd and Zn in two bivalves. II. Significance of trophically available metal (TAM)

    Science.gov (United States)

    Wallace, W.G.; Luoma, S.N.

    2003-01-01

    This paper examines how the subcellular partitioning of Cd and Zn in the bivalves Macoma balthica and Potamocorbula amurensis may affect the trophic transfer of metal to predators. Results show that the partitioning of metals to organelles, 'enzymes' and metallothioneins (MT) comprise a subcellular compartment containing trophically available metal (TAM; i.e. metal trophically available to predators), and that because this partitioning varies with species, animal size and metal, TAM is similarly influenced. Clams from San Francisco Bay, California, were exposed for 14 d to 3.5 ??g 1-1 Cd and 20.5 ??g 1-1 Zn, including 109Cd and 65Zn as radiotracers, and were used in feeding experiments with grass shrimp Palaemon macrodatylus, or used to investigate the subcellular partitioning of metal. Grass shrimp fed Cd-contaminated P. amurensis absorbed ???60% of ingested Cd, which was in accordance with the partitioning of Cd to the bivalve's TAM compartment (i.e. Cd associated with organelles, 'enzymes' and MT); a similar relationship was found in previous studies with grass shrimp fed Cd-contaminated oligochaetes. Thus, TAM may be used as a tool to predict the trophic transfer of at least Cd. Subcellular fractionation revealed that ???34% of both the Cd and Zn accumulated by M. balthica was associated with TAM, while partitioning to TAM in P. amurensis was metal-dependent (???60% for TAM-Cd%, ???73% for TAM-Zn%). The greater TAM-Cd% of P. amurensis than M. balthica is due to preferential binding of Cd to MT and 'enzymes', while enhanced TAM-Zn% of P. amurensis results from a greater binding of Zn to organelles. TAM for most species-metal combinations was size-dependent, decreasing with increased clam size. Based on field data, it is estimated that of the 2 bivalves, P. amurensis poses the greater threat of Cd exposure to predators because of higher tissue concentrations and greater partitioning as TAM; exposure of Zn to predators would be similar between these species.

  1. Determination of Cr, Cd, Sn, and Pb in Selected Herbal Products Available in Philippine Markets

    Directory of Open Access Journals (Sweden)

    Joan S. De Vera

    2017-12-01

    Full Text Available The growing popularity of herbal products in the Philippines makes it imperative to monitor and ensure safety of consumers from metal contaminants. In this study, trace concentrations of Cr, Cd, Sn, and Pb in herbal products were simultaneously measured using a microwaveassisted digestion as sample pre-treatment and inductively coupled plasma mass spectrometry (ICP-MS for elemental detection. Using the optimized method, recoveries of ERM CD281, the primary cer t i f ied reference material (CRM used, were found to be between 80-89%, and the method detection limits (MDL for Cr, Cd, Sn, and Pb were 0.15, 0.07, 0.3, and 0.14 μg/L, respectively. The linear ranges for Cr and other elements (Cd, Sn, and Pb were 0.01-500 and 0.01-50 μg/L, respectively. All correlation coeff icients were 0.9999 or better. Most of the products tested had measurable trace metal concentrations, which were below the suggested maximum limits in herbal products. However, one product derived from mangosteen exceeded the limit for Cd (0.42 mg/kg. Subsequent analysis of metal content in tea infusions showed that only a small fraction of metals may leach out, suggesting that consumption of tea infusions pose lesser risks. The order of abundance of metals found in herbal products was Cr>Pb>Cd>Sn. The variability of metal concentrations in herbal products underlines the fact that many plant ingredients are susceptible to contamination, and quality control during processing must be improved to minimize the possibility of contamination. The results of this study suggest that vigilant monitoring of herbal products is imperative to avoid exposure to trace metal contamination.

  2. Enhanced solar cell efficiency and stability using ZnS passivation layer for CdS quantum-dot sensitized actinomorphic hexagonal columnar ZnO

    International Nuclear Information System (INIS)

    Chen, Yanli; Tao, Qiang; Fu, Wuyou; Yang, Haibin; Zhou, Xiaoming; Zhang, Yanyan; Su, Shi; Wang, Peng; Li, Minghui

    2014-01-01

    Highlights: • The synthetic of ZnS/CdS QDs/AHC-ZnO photoanode with a simple method. • The power conversion efficiency of the ZnS/CdS QDs/AHC-ZnO is 1.81%. • The effects of photovoltaic performances caused by CdS and ZnS amounts were studied. • ZnS passivation layer enhanced electron lifetime significantly. - Abstract: We report the photoanodes consisting of CdS quantum-dots (QDs) sensitized actinomorphic hexagonal columnar ZnO (CdS QDs/AHC-ZnO) with ZnS passivation layer are applied for solar cells. Simple chemical solution synthesized AHC-ZnO films on transparent conducting glass substrates, and then, AHC-ZnO is functionalized with uniform CdS and ZnS QDs via successive ionic layer adsorption and reaction (SILAR) method. The as-prepared materials were characterized by XRD, SEM, TEM, UV–vis diffused reflectance absorption spectra and photovoltaic performances analysis. Photovoltaic performances results indicate the quantity of CdS QDs as well as the visible light absorption threshold can be effectively controlled by varying the coating cycles during the SILAR process, and the photocurrent density (Jsc) is greatly improved by increasing the amount of ZnS. By optimizing the AHC-ZnO with the amount of CdS and ZnS, the best efficiency of 1.81% was achieved for solar cell under AM 1.5 G illumination with Jsc = 7.44 mA/cm 2 , Voc = 0.57 V and FF = 43%

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

    Science.gov (United States)

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

    2015-09-01

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