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

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

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

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.

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

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

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)

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)

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...

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-.

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.

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

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.

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.

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.

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.)

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.)

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.

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.

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

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.

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.

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.

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

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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.

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.

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.

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.

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.

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

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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.

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.

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.

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.

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.

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.

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

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.

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.

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 ...

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.

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.

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

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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.

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

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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.

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.

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.

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)

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)

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

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

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

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.

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

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

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

Directory of Open Access Journals (Sweden)

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.

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

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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.

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.

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.

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

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

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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.

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.

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

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

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.

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

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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.

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

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

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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.

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

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P. Licata

2010-01-01

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

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.

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.

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.

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.

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.

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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 > Zn ≈ Cd 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

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

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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.

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

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

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

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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.

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

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

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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

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

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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.

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.

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

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.

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...

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

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

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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.

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

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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.

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.

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

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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.

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.

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

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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.

High-Efficiency Photochemical Water Splitting of CdZnS/CdZnSe Nanostructures

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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.

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)

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

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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.

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

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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.

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.

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.

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

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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.

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

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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

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.

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.

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.

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.

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....

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.

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

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

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.

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.

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.

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+.

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.

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.

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.

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.

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.  

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 ...

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

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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.

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

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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

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

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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.

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

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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.

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

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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.

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

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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.

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

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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

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

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.

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.

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

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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.

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

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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.

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.

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

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

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.

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

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

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.

Adsorpsi Pb2+ dan Zn2+ pada Biomassa Imperata cylindrica

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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%.

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, ...

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

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.

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 ...

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.

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

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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.

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

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

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.

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.

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.

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.

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.

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.

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

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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

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

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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

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)

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.

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.

One-step synthesis of PbSe-ZnSe composite thin film

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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.

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+.

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...

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.

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.

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...

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}.

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.

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.

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.

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

[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.

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.

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.

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.

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.

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.

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.

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

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

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

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.

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.

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.

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.

Temporal Variation and Ecological Risk Assessment of Metals in Soil Nearby a Pb⁻Zn Mine in Southern China.

Science.gov (United States)

Cao, Congcong; Wang, Li; Li, Hairong; Wei, Binggan; Yang, Linsheng

2018-05-09

Metal contamination in soil from tailings induces risks for the ecosystem and for humans. In this study, the concentrations and ecological risks of Cd, Cu, Pb, and Zn in soil contaminated by a tailing from Yangshuo (YS) lead and zinc (Pb⁻Zn) mine, which collapsed for more than 40 years, were determined in 2015. The mean concentrations of Zn, Pb, Cu, and Cd were 1301.79, 768.41, 82.60, and 4.82 mg/kg, respectively, which, with years of remediation activities, decreased by 66.9%, 61.7%, 65.4%, and 65.3% since 1986, but still exceed the national standards. From 1986 to 2015, soil pH increased significantly, with available concentrations of Zn, Pb, Cu and Cd decreasing by 13%, 81%, 77%, and 67%, respectively, and potential ecological risk indexes ( E r ) of the determined metals decreasing by more than 60%. Horizontally, total contents and percentages of available concentrations of Zn, Pb, Cu, and Cd decreased with the distance from the tailing heap in SD village, while pH values showed the reverse pattern. Vertically, Zn and Cd, Pb, and Cu showed similar vertical distribution patterns in the soil profiles. There was a slight downward migration for the determined metals in soil of M and H area and the mobility was in the order of Cd > Zn > Pb > Cu. It can be concluded that although concentrations and ecological risks of Cd, Cu, Pb, and Zn in soil decreased significantly, SD village is still a high risk area, and the priority pollutant is Cd.

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

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

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

Heavy metals pollution and pb isotopic signatures in surface sediments collected from Bohai Bay, North China.

Science.gov (United States)

Gao, Bo; Lu, Jin; Hao, Hong; Yin, Shuhua; Yu, Xiao; Wang, Qiwen; Sun, Ke

2014-01-01

To investigate the characteristics and potential sources of heavy metals pollution, surface sediments collected from Bohai Bay, North China, were analyzed for the selected metals (Cd, Cr, Cu, Ni, Pb, and Zn). The Geoaccumulation Index was used to assess the level of heavy metal pollution. Pb isotopic compositions in sediments were also measured to effectively identify the potential Pb sources. The results showed that the average concentrations of Cd, Cr, Cu, Ni, Pb, and Zn were 0.15, 79.73, 28.70, 36.56, 25.63, and 72.83 mg/kg, respectively. The mean concentrations of the studied metals were slightly higher than the background values. However, the heavy metals concentrations in surface sediments in Bohai Bay were below the other important bays or estuaries in China. The assessment by Geoaccumulation Index indicated that Cr, Zn, and Cd were classified as "the unpolluted" level, while Ni, Cu, and Pb were ranked as "unpolluted to moderately polluted" level. The order of pollution level of heavy metals was: Pb > Ni > Cu > Cr > Zn > Cd. The Pb isotopic ratios in surface sediments varied from 1.159 to 1.185 for (206)Pb/(207)Pb and from 2.456 to 2.482 for (208)Pb/(207)Pb. Compared with Pb isotopic radios in other sources, Pb contaminations in the surface sediments of Bohai Bay may be controlled by the mix process of coal combustion, aerosol particles deposition, and natural sources.

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.

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

Directory of Open Access Journals (Sweden)

NI Zhong-ying

2017-05-01

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

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.

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.

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

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)

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.

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

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

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

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

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.

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

Phosphine-free synthesis of high-quality reverse type-I ZnSe/CdSe core with CdS/CdxZn1 - xS/ZnS multishell nanocrystals and their application for detection of human hepatitis B surface antigen

Science.gov (United States)

Shen, Huaibin; Yuan, Hang; Niu, Jin Zhong; Xu, Shasha; Zhou, Changhua; Ma, Lan; Li, Lin Song

2011-09-01

Highly photoluminescent (PL) reverse type-I ZnSe/CdSe nanocrystals (NCs) and ZnSe/CdSe/CdS/CdxZn1 - xS/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/CdxZn1 - xS/ZnS NCs were synthesized in a large scale synthesis. After the overgrowth of a CdS/CdxZn1 - xS/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/CdxZn1 - xS/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/CdxZn1 - xS/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 - 1.

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

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.

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

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

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.

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

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.

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.

Origin of localized states in zinc-blende ZnCdSe thin films and the influence on carrier relaxation of self-assembled ZnTe/ZnCdSe quantum dots

International Nuclear Information System (INIS)

Lee, Ling; Dai, Yue-Ru; Yang, Chu-Shou; Fan, Wen-Chung; Chou, Wu-Ching

2015-01-01

Highlights: • The localized emission in zinc-blende ZnCdSe is induced by excess selenium. • An optimized growth is demonstrated as the VI/II ratio approaches unity. • Size-independent lifetimes are observed in ZnTe/ZnCdSe quantum dots. • Localized electrons in the capping layer dominate size-independent lifetimes. - Abstract: This study discovered the origin of deep level emission in zinc-blende ZnCdSe thin films grown by molecular beam epitaxy, in which a localization behavior was noticed. Pronounced deep level emission observed in films grown under a VI/II ratio of 1.74 (Se-accumulated regime) could be suppressed by a lower VI/II ratio of 1.04 (intermediate regime) and 0.74 (metal-rich regime). Hence the localized states could be correlated to excess selenium accumulated at the growth surface. The localized states also influence the carrier relaxation process of self-assembled ZnTe quantum dots embedded in a ZnCdSe matrix. Once quantum dots surmount the wetting layer, localized electrons in the capping layer dominate the type-II transition and exhibit size-independent lifetimes

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.)

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.

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.

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.

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.

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)

Influence of CdTe sub-monolayer stressor on CdSe quantum dot self-assembling in ZnSe

International Nuclear Information System (INIS)

Sedova, I.V.; Lyublinskaya, O.G.; Sorokin, S.V.; Sitnikova, A.A.; Solnyshkov, D.D.; Rykhova, O.V.; Toropov, A.A.; Ivanov, S.V.

2006-01-01

This paper reports on the attempt to apply the stressor-controlled quantum dot (QD) fabrication technique to the conventional CdSe/ZnSe nanostructures. Super-strained CdTe fractional monolayer (Δa/a∝14% for CdTe/ZnSe) grown on top of the Te-stabilized ZnSe surface prior to deposition of the QD material (CdSe) has been used as a stressor which is expected to affect size, composition and density of CdSe QDs. The grown structures are studied by X-ray diffraction, transmission-electron microscopy, photoluminescence (PL) and PL excitation in comparison with conventional CdSe/ZnSe QDs obtained by a modified migration enhanced epitaxy technique. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

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.

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

Influence of CdCl{sub 2} activation treatment on ultra-thin Cd{sub 1−x}Zn{sub x}S/CdTe solar cells

Energy Technology Data Exchange (ETDEWEB)

Clayton, A.J., E-mail: a.clayton@glyndwr.ac.uk [Centre for Solar Energy Research, Glyndŵr University, OpTIC, St. Asaph LL17 0JD (United Kingdom); Baker, M.A.; Babar, S. [Faculty of Engineering & Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom); Gibson, P.N. [Institute for Health & Consumer Protection, Joint Research Centre, 21020 Ispra, VA (Italy); Irvine, S.J.C.; Kartopu, G.; Lamb, D.A.; Barrioz, V. [Centre for Solar Energy Research, Glyndŵr University, OpTIC, St. Asaph LL17 0JD (United Kingdom)

2015-09-01

Ultra-thin CdTe photovoltaic solar cells with an absorber thickness of 0.5 μm were produced by metal organic chemical vapour deposition onto indium tin oxide coated boroaluminosilicate glass. A wide band gap Cd{sub 1−x}Zn{sub x}S alloy window layer was employed to improve spectral response in the blue region of the solar spectrum. X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy were used to monitor changes in the chemical composition and microstructure of the Cd{sub 1−x}Zn{sub x}S/CdTe solar cell after varying the post-deposition CdCl{sub 2} activation treatment time and annealing temperature. The CdCl{sub 2} treatment leached Zn from the Cd{sub 1−x}Zn{sub x}S layer causing a redshift in the spectral response onset of window absorption. S diffusion occurred across the Cd{sub 1−x}Zn{sub x}S/CdTe interface, which was more pronounced as the CdCl{sub 2} treatment was increased. A CdTe{sub 1−y}S{sub y} alloy was formed at the interface, which thickened with CdCl{sub 2} treatment time. Small concentrations of S (up to 2 at.%) were observed throughout the CdTe layer as the degree of CdCl{sub 2} treatment was increased. Greater S diffusion across the Cd{sub 1−x}Zn{sub x}S/CdTe interface caused the device open-circuit voltage (V{sub oc}) to increase. The higher V{sub oc} is attributed to enhanced strain relaxation and associated reduction of defects in the interface region as well as the increase in CdTe grain size. - Highlights: • Increased CdCl{sub 2} activation treatment resulted in loss of Zn from Cd{sub 1−x}Zn{sub x}S. • Sulphur diffusion into CdTe was enhanced with greater CdCl{sub 2} activation treatment. • Improvement to V{sub oc} correlated with increased sulphur diffusion into CdTe.

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.

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

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.

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

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.)

[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

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

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...

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.

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

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.

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

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.

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.

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.)

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.

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

[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.

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

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).

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

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

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

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.

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

Interfacial passivation of CdS layer to CdSe quantum dots-sensitized electrodeposited ZnO nanowire thin films

International Nuclear Information System (INIS)

Zhang, Jingbo; Sun, Chuanzhen; Bai, Shouli; Luo, Ruixian; Chen, Aifan; Sun, Lina; Lin, Yuan

2013-01-01

ZnO porous thin films with nanowire structure were deposited by the one-step electrochemical deposition method. And a CdS layer was coated on the as-deposited ZnO nanowire thin films by successive ionic layer adsorption and reaction (SILAR) method to passivate surface states. Then the films were further sensitized by CdSe quantum dots (QDs) to serve as a photoanode for fabricating quantum dots-sensitized solar cells (QDSSCs). The effect of the CdS interfacial passivation layer on the performance of the QDSSCs was systematically investigated by varying the SILAR cycle number and heating the passivation layer. The amorphous CdS layer with an optimized thickness can effectively suppress the recombination of the injected electrons with holes on QDs and the redox electrolyte. The newly formed CdS layer on the surface of the ZnO nanowire thin film obviously prolongs the electron lifetime in the passivated ZnO nanoporous thin film because of the lower surface trap density in the ZnO nanowires after CdS deposition, which is favorable to the higher short-circuit photocurrent density (J sc ). For the CdSe QDs-sensitized ZnO nanoporous thin film with the interfacial passivation layer, the J sc and conversion efficiency can reach a maximum of 8.36 mA cm −2 and 2.36%, respectively. The conversion efficiency was improved by 83.47% compared with that of the cell based on the CdSe QDs-sensitized ZnO nanoporous thin film without CdS interfacial passivation (0.39%)

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)

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.

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.)

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.

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%

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.

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).

Pollution and ecological risk assessment of heavy metals in the soil-plant system and the sediment-water column around a former Pb/Zn-mining area in NE Morocco.

Science.gov (United States)

El Azhari, Abdellah; Rhoujjati, Ali; El Hachimi, Moulay Laârabi; Ambrosi, Jean-Paul

2017-10-01

This study discussed the environmental fate and ecological hazards of heavy metals in the soil-plant system and sediment-water column around the former Pb-Zn mining Zeïda district, in Northeastern Morocco. Spatial distribution, pollution indices, and cluster analysis were applied for assessing Pb, Zn, As, Cu and Cd pollution levels and risks. The geo-accumulation index (I geo ) was determined using two different geochemical backgrounds: i) the commonly used upper crust values, ii) local geochemical background calculated with exploratory data analysis. The soils in the vicinity of the tailings, as well as the sediments downstream of the latter, displayed much higher metal concentrations, I geo, and potential ecology risk coefficient values than other sites, classifying these sites as highly contaminated and severely hazardous. The concentrations of Pb in contaminated sediment samples also exceeded the PEC limits and are expected to cause harmful effects on sediment-dwelling organisms. Based on the comparison with the toxicity limits, the most contaminated plant samples were found around the tailings piles. The metal concentrations in both raw and filtrated water samples were overall below the drinking water standards in samples upstream and downstream of the mining center, indicating that heavy metals levels in the Moulouya River surface waters were not affected by the tailings spill. Cluster analysis suggest that: i) Pb and Zn in sediments were derived from the abandoned tailings and are mainly stored and transported as particle-bound to the bedload, ii) Pb, Zn, and Cu in the soil-plant system were related to the dispersion of tailings materials while As and Cd originated primarily from natural geological background in both the soil-plant and the water-sediment systems. Copyright © 2017 Elsevier Inc. All rights reserved.

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...

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

Science.gov (United States)

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

2008-06-15

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2008-06-15

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

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

International Nuclear Information System (INIS)

Vilar, Vitor J.P.; Loureiro, Jose M.; Botelho, Cidalia M.S.; Boaventura, Rui A.R.

2008-01-01

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

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

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.

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 ...

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.

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.

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.

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.

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.

Discovery of Wolitu Pb-Zn deposit through geochemical prospecting under loess cover in Inner Mongolia, China

Directory of Open Access Journals (Sweden)

Fan Yang

2017-09-01

Full Text Available We report the finding of the Wolitu Pb-Zn deposit in Inner Mongolia, China, through a series of geochemical surveys. The Wolitu area, located in the loess-cover area in the Hure Banner, Tongliao City, Inner Mongolia, and neighboring the Horqin Sandy Land to the north, had no previous history of Pb-Zn mining or record of Pb-Zn mineralization. Our study identified a large Pb-Zn anomaly with potential zones of mineralization by stream sediment survey. Random rock sampling reveals limonitization at sporadic outcrops in the gullies. The high concentrations of Pb in the residual debris provided guidelines to fix the position for exploratory trench. Oxidized concealed orebodies were identified by trenching. Blind orebodies in veins hosted within the structural zone between slates and marbles of the upper Carboniferous Shizuizi Formation and the Permian granite were discovered by drilling. It is computed that the ore reserve may reach up to 540,000 tones with Pb grade of 1.27% and Zn of 1.9%. This case study is an excellent example for identifying potential polymetallic deposits in loess covered terrains using geochemical exploration.

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)

Cd and Zn interactions and toxicity in ectomycorrhizal basidiomycetes in axenic culture

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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

Changes in heavy metal bioavailability and speciation from a Pb-Zn mining soil amended with biochars from co-pyrolysis of rice straw and swine manure.

Science.gov (United States)

Meng, Jun; Tao, Mengming; Wang, Lili; Liu, Xingmei; Xu, Jianming

2018-08-15

Biochar has been utilized as a good amendment to immobilize heavy metals in contaminated soils. However, the effectiveness of biochar in metal immobilization depends on biochar properties and metal species. In this study, the biochars produced from co-pyrolysis of rice straw with swine manure at 400°C were investigated to evaluate their effects on bioavailability and chemical speciation of four heavy metals (Cd, Cu, Pb and Zn) in a Pb-Zn contaminated soil through incubation experiment. Results showed that co-pyrolysis process significantly change the yield, ash content, pH, and electrical conductivity (EC) of the blended biochars compared with the single straw/manure biochar. The addition of these biochars significantly increased the soil pH, EC, and dissolved organic carbon (DOC) concentrations. The addition of biochars at a rate of 3% significantly reduced the CaCl 2 -extractable metal concentrations in the order of Pb>Cu>Zn>Cd. The exchangeable heavy metals decreased in all the biochar-amended soils whereas the carbonate-bound metal speciation increased. The increase in soil pH and the decrease in the CaCl 2 extractable metals indicated that these amendments can directly transform the highly availability metal speciation to the stable speciation in soils. In conclusion, biochar derived from co-pyrolysis of rice straw with swine manure at a mass ratio of 3:1 could most effectively immobilize the heavy metals in the soil. Copyright © 2018 Elsevier B.V. All rights reserved.

Geochemical and Pb isotopic evidence for sources and dispersal of metal contamination in stream sediments from the mining and smelting district of Pribram, Czech Republic

International Nuclear Information System (INIS)

Ettler, Vojtech; Mihaljevic, Martin; Sebek, Ondrej; Molek, Michael; Grygar, Tomas; Zeman, Josef

2006-01-01

Stream sediments from the mining and smelting district of Pribram, Czech Republic, were studied to determine the degree, sources and dispersal of metal contamination using a combination of bulk metal and mineralogical determinations, sequential extractions and Pb isotopic analyses. The highest metal concentrations were found 3-4 km downstream from the main polymetallic mining site (9800 mg Pb kg -1 , 26 039 mg Zn kg -1 , 316.4 mg Cd kg -1 , 256.9 mg Cu kg -1 ). The calculated enrichment factors (EFs) confirmed the extreme degree of contamination by Pb, Zn and Cd (EF > 40). Lead, Zn and Cd are bound mainly to Fe oxides and hydroxides. In the most contaminated samples Pb is also present as Pb carbonates and litharge (PbO). Lead isotopic analysis indicates that the predominant source of stream sediment contamination is historic Pb-Ag mining and primary Pb smelting ( 206 Pb/ 207 Pb = 1.16), while the role of secondary smelting (car battery processing) is negligible. - Pb isotopes properly complete traditional investigations of metal sources and dispersal in contaminated stream sediments

Comprehensive study of growth mechanism and properties of low Zn content Cd_1_-_xZn_xS thin films by chemical bath

International Nuclear Information System (INIS)

Rodriguez, Carlos Anibal; Sandoval-Paz, Myrna Guadalupe; Saavedra, Renato; De la Carrera, Francisco; Trejo-Cruz, Cuauhthemoc; Aragon, Luis E.; Sirena, Martin; Delplancke, Marie-Paule; Carrasco, Claudia

2016-01-01

Cd_1_-_xZn_xS thin films have been studied extensively as window layers for solar cell applications. However, a mismatch between the Cd_1_-_xZn_xS and copper-indium-gallium-selenide absorber layers increases with Zn film concentration, which reduces the device efficiency. In this work, Cd_1_-_xZn_xS thin films with low Zn concentrations were analyzed. The effect of the addition of different molar Zn concentrations to the reaction mixture on the growth mechanism of Cd_1_-_xZn_xS thin films and the influence of these mechanisms on structural, optical and morphological properties of the films has been studied. Cd_1_-_xZn_xS thin films were synthesized by chemical bath deposition using an ammonia-free alkaline solution. Microstructural analysis by X-ray diffraction showed that all deposited films grew with hexagonal structure and crystallite sizes decreased as the Zn concentration in the film increased. Optical measurements indicated a high optical transmission between 75% and 90% for wavelengths above the absorption edge. Band gap value increased from 2.48 eV to 2.62 eV, and the refractive index values for Cd_1_-_xZn_xS thin films decreased as the Zn increased. These changes in films and properties are related to a modification in growth mechanism of the Cd_1_-_xZn_xS thin films, with the influence of Zn(OH)_2 formation being more important as Zn in solution increases. (author)

Study of CdTe:Cl and CdZnTe detectors for medical multi-slices X-ray Computed Tomography; Etude de detecteurs en CdTe:Cl et CdZnTe pour la tomographie X medicale multicoupes

Energy Technology Data Exchange (ETDEWEB)

Ricq, St

1999-09-28

The application of CdTe and CdZnTe detectors to medical X-ray Computed Tomography have been investigated. Different electrodes (Au, Pt, In) have been deposited on CdZnTe HPBM and on CdTe:ClTHM. Their injection properties have been determined with Current-Voltage characteristics. Under X-ray in CT conditions, injection currents measurements reveal trapped carriers space-charges formation. The same way, the comparisons of the responses to X-beam cut-off with various injection possibilities enable to follow the space-charges evolutions and then to determine the predominant traps types. Nevertheless, both hole and electron traps are responsible for the memory effect e.g. the currents levels dependence with irradiation history. This effect is noticed in particular on responses to fast flux variations that simulate scanner's conditions. Trap levels probably corresponding to native defects are responsible for these limitations. In order to make such detectors suitable for X-ray Computed Tomography, significant progresses in CdTe for CdZnTe crystal growth with an important defects densities reduction (factor 10), or possibly counting mode operation, seem necessary. (author)

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.

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

Abandoned Pb−Zn mining wastes and their mobility as proxy to toxicity: A review

Energy Technology Data Exchange (ETDEWEB)

Gutiérrez, Mélida, E-mail: mgutierrez@missouristate.edu [Department of Geography, Geology and Planning, Missouri State University, Springfield, MO 65897 (United States); Mickus, Kevin, E-mail: kevinmickus@missouristate.edu [Department of Geography, Geology and Planning, Missouri State University, Springfield, MO 65897 (United States); Camacho, Lucy Mar, E-mail: lucy.camacho@tamuk.edu [Department of Environmental Engineering, Texas & M University-Kingsville, Kingsville, TX 78363 (United States)

2016-09-15

Lead and zinc (Pb−Zn) mines are a common occurrence worldwide; and while approximately 240 mines are active, the vast majority have been abandoned for decades. Abandoned mining wastes represent a serious environmental hazard, as Pb, Zn and associated metals are continuously released into the environment, threatening the health of humans and affecting ecosystems. Iron sulfide minerals, when present, can form acid mine drainage and increase the toxicity by mobilizing the metals into more bioavailable forms. Remediation of the metal waste is costly and, in the case of abandoned wastes, the responsible party(ies) for the cleanup can be difficult to determine, which makes remediation a complex and lengthy process. In this review, we provide a common ground from a wide variety of investigations about concentrations, chemical associations, and potential mobility of Pb, Zn and cadmium (Cd) near abandoned Pb−Zn mines. Comparing mobility results is a challenging task, as instead of one standard methodology, there are 4–5 different methods reported. Results show that, as a general consensus, the metal content of soils and sediments vary roughly around 1000 mg/kg for Zn, 100 for Pb and 10 for Cd, and mobilities of Cd > Zn > Pb. Also, mobility is a function of pH, particle size, and formation of secondary minerals. New and novel remediation techniques continue to be developed in laboratories but have seldom been applied to the field. Remediation at most of the sites has consisted of neutralization (e.g. lime,) for acid mine discharge, and leveling followed by phytostabilization. In the latter, amendments (e.g. biochar, fertilizers) are added to boost the efficiency of the treatment. Any remediation method has to be tested before being implemented as the best treatment is site-specific. Potential treatments are described and compared. - Highlights: • Abandoned Pb−Zn mine wastes represent a hazard to the environment. • Cd is a toxic metal closely associated to Zn and

Abandoned Pb−Zn mining wastes and their mobility as proxy to toxicity: A review

International Nuclear Information System (INIS)

Gutiérrez, Mélida; Mickus, Kevin; Camacho, Lucy Mar

2016-01-01

Lead and zinc (Pb−Zn) mines are a common occurrence worldwide; and while approximately 240 mines are active, the vast majority have been abandoned for decades. Abandoned mining wastes represent a serious environmental hazard, as Pb, Zn and associated metals are continuously released into the environment, threatening the health of humans and affecting ecosystems. Iron sulfide minerals, when present, can form acid mine drainage and increase the toxicity by mobilizing the metals into more bioavailable forms. Remediation of the metal waste is costly and, in the case of abandoned wastes, the responsible party(ies) for the cleanup can be difficult to determine, which makes remediation a complex and lengthy process. In this review, we provide a common ground from a wide variety of investigations about concentrations, chemical associations, and potential mobility of Pb, Zn and cadmium (Cd) near abandoned Pb−Zn mines. Comparing mobility results is a challenging task, as instead of one standard methodology, there are 4–5 different methods reported. Results show that, as a general consensus, the metal content of soils and sediments vary roughly around 1000 mg/kg for Zn, 100 for Pb and 10 for Cd, and mobilities of Cd > Zn > Pb. Also, mobility is a function of pH, particle size, and formation of secondary minerals. New and novel remediation techniques continue to be developed in laboratories but have seldom been applied to the field. Remediation at most of the sites has consisted of neutralization (e.g. lime,) for acid mine discharge, and leveling followed by phytostabilization. In the latter, amendments (e.g. biochar, fertilizers) are added to boost the efficiency of the treatment. Any remediation method has to be tested before being implemented as the best treatment is site-specific. Potential treatments are described and compared. - Highlights: • Abandoned Pb−Zn mine wastes represent a hazard to the environment. • Cd is a toxic metal closely associated to Zn and

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

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.

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)

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.

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.

Field evaluation of the effectiveness of three industrial by-products as organic amendments for phytostabilization of a Pb/Zn mine tailings.

Science.gov (United States)

Yang, Shengxiang; Cao, Jianbing; Li, Fengmei; Peng, Xizhu; Peng, Qingjing; Yang, Zhihui; Chai, Liyuan

2016-01-01

Although the potential of industrial by-products as organic amendments for phytostabilization has long been recognized, most of the previous studies addressing this issue have been laboratory-based. In this study, a field trial was conducted to evaluate the effectiveness of three industrial by-products [sweet sorghum vinasse (SSV), medicinal herb residues (MHR) and spent mushroom compost (SMC)] as organic amendments for phytostabilization of abandoned Pb/Zn mine tailings. Our results showed the following: (i) when compared to the control tailings, the mean concentrations of diethylene-triamine-pentaacetic acid (DTPA)-extractable Cd, Cu, Pb and Zn in SSV, MHR and SMC treatments decreased by 20.8-28.0%, 41.6-49.1%, 17.7-22.7% and 9.5-14.7%, respectively; (ii) the mean values of organic C, ammonium-N and available P in SSV, MHR and SMC treatments increased by 1.7-2.8, 10.8-14.9 and 3.9-5.1 times as compared with the mine tailings; and (iii) the addition of SSV, MHR and SMC significantly enhanced soil respiration and microbial biomass being 1.5-1.8 and 1.3-1.6 fold higher than those in the control tailings. There were no significant differences in soil biochemical properties among the plots amended with these by-products, suggesting that they were almost equally effective in improving the biochemical conditions of the tailings. In addition, the application of these amendments promoted seed germination, seedling growth, and consequently increased the vegetation cover and its biomass. Moreover, concentrations of Cd, Cu, Pb and Zn in above-ground parts of the plants were below the toxicity limit levels for animals. The results obtained in this field study confirmed that the three organic-rich industrial by-products could be used as amendments for phytostabilization of some types of mine tailings.

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)

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.

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.

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.

Atomistic tight-binding computations of the structural and optical properties of CdTe/CdX (X=S and Se)/ZnS core/shell/shell nanocrystals

Science.gov (United States)

Sukkabot, Worasak

2018-05-01

A study of CdTe/CdX (X=S and Se)/ZnS core/shell/shell nanocrystals is carried out using atomistic tight-binding theory and the configuration interaction method to provide information for applications in bioimaging, biolabeling, display devices and near-infrared electronic instruments. The calculations yield the dependences of the internal and external passivated shells on the natural behaviours of CdTe/CdX (X=S and Se)/ZnS core/shell/shell nanocrystals. The reduction of the optical band gaps is observed with increasing numbers of monolayers in the external ZnS shell due to quantum confinement. Interestingly, the optical band gaps of CdTe/CdS/ZnS core/shell/shell nanocrystals are greater than those of CdTe/CdSe/ZnS core/shell/shell nanocrystals. In the presence of an external ZnS-coated shell, electron-hole wave function overlaps, oscillation strengths, ground-state exchange energies and Stokes shift are improved, whereas ground-state coulomb energies and fine-structure splitting are reduced. The oscillation strengths, Stokes shift and fine-structure splitting are reduced with the increase in external ZnS shell thickness. The oscillation strengths, Stokes shift and fine-structure splitting of CdTe/CdS/ZnS core/shell/shell nanocrystals are larger than those of CdTe/CdSe/ZnS core/shell/shell nanocrystals. Reduction of the atomistic electron-hole interactions is observed with increasing external ZnS shell size. The strong electron-hole interactions are more probed in CdTe/CdS/ZnS core/shell/shell nanocrystals than in CdTe/CdSe/ZnS core/shell/shell nanocrystals.

Selective UV radiation detection on the basis of low-dimensional ZnCdS/ZnMgS/GaP and ZnCdS/ZnS/GaP heterostructures

Energy Technology Data Exchange (ETDEWEB)

Averin, S. V., E-mail: sva278@ire216.msk.su; Kuznetzov, P. I.; Zhitov, V. A.; Zakharov, L. Yu.; Kotov, V. M.; Alkeev, N. V. [Russian Academy of Sciences, Fryazino Branch, Kotel’nikov Institute of Radio Engineering and Electronics (Russian Federation); Gladisheva, N. B. [Pulsar State Plant (Russian Federation)

2015-11-15

The detecting properties of periodic heterostructures with ZnCdS quantum wells separated by ZnMgS or ZnS barrier layers are studied. Heterostructures are grown on semi-insulating GaP substrates by metal organic vapor-phase epitaxy (MOVPE). On their basis, metal–semiconductor–metal (MSM) diodes with interdigital Schottky contacts 3 μm, distances between them of 3 μm, and a total detector area of 100 × 100 μm are fabricated. The detectors have low dark currents (10{sup –12} A); at low bias voltages, they provide a narrow- band response (full-width at half-maximum of FWHM = 18 nm at a wavelength of 350 nm) which is controlled by the ZnCdS quantum-well composition. As bias is increased to 70 V, the maximum detector sensitivity shifts by a wavelength of 450 nm, which is caused by penetration of the external-bias electric field into the semi-insulating GaP substrate. In this case, the narrow-band response of the detector at a wavelength of 350 nm is retained, i.e., the two-color detection of light is provided.

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.

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%.

Study of CdTe:Cl and CdZnTe detectors for medical multi-slices X-ray Computed Tomography; Etude de detecteurs en CdTe:Cl et CdZnTe pour la tomographie X medicale multicoupes

Energy Technology Data Exchange (ETDEWEB)

Ricq, St

1999-09-28

The application of CdTe and CdZnTe detectors to medical X-ray Computed Tomography have been investigated. Different electrodes (Au, Pt, In) have been deposited on CdZnTe HPBM and on CdTe:ClTHM. Their injection properties have been determined with Current-Voltage characteristics. Under X-ray in CT conditions, injection currents measurements reveal trapped carriers space-charges formation. The same way, the comparisons of the responses to X-beam cut-off with various injection possibilities enable to follow the space-charges evolutions and then to determine the predominant traps types. Nevertheless, both hole and electron traps are responsible for the memory effect e.g. the currents levels dependence with irradiation history. This effect is noticed in particular on responses to fast flux variations that simulate scanner's conditions. Trap levels probably corresponding to native defects are responsible for these limitations. In order to make such detectors suitable for X-ray Computed Tomography, significant progresses in CdTe for CdZnTe crystal growth with an important defects densities reduction (factor 10), or possibly counting mode operation, seem necessary. (author)

Deposition of polycrystalline Cd{sub 1-x}Zn{sub x} Te films on ZnTe/graphite and graphite substrates by close-spaced sublimation

Energy Technology Data Exchange (ETDEWEB)

Okamoto, Tamotsu; Akiba, Sho; Takahashi, Kohei; Nagatsuka, Satsuki; Kanda, Yohei [Department of Electrical and Electronic Engineering, Kisarazu National College of Technology, 2-11-1 Kiyomidai-higashi, Kisarazu, Chiba 292-0041 (Japan); Tokuda, Satoshi; Kishihara, Hiroyuki; Sato, Toshiyuki [Technology Research Laboratory, Shimadzu Corporation, 3-9-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0237 (Japan)

2014-07-15

The effects of a ZnTe layer on the deposition of a Cd{sub 1-x}Zn{sub x}Te (CZT) layer in the initial stage of the close-spaced sublimation (CSS) deposition were investigated. The deposition rate was almost constant in the initial stage of the CdTe deposition on the ZnTe/graphite substrates. However, the deposition rate within 1 minute was lower than that after 1 minute in the CdTe deposition on graphite substrates. This result suggests that nucleation of CdTe directly deposited on graphite substrate is difficult when compared to that with a ZnTe layer. Furthermore, the effects of CdCl{sub 2} and ZnTe additions to the CdTe sources in the CSS deposition were also investigated. Both the grain size and the intensity of donor-acceptor pair (DAP) emission in photoluminescence (PL) spectra were decreased by the effect of CdCl{sub 2} addition. Zn content in CZT films was controlled by the ZnTe ratio in the CdTe/ZnTe powder sources. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Synthesis of Aqueous CdTe/CdS/ZnS Core/shell/shell Quantum Dots by a Chemical Aerosol Flow Method

Directory of Open Access Journals (Sweden)

Chen Dong

2009-01-01

Full Text Available Abstract This work described a continuous method to synthesize CdTe/CdS/ZnS core/shell/shell quantum dots. In an integrated system by flawlessly combining the chemical aerosol flow system working at high temperature (200–300°C to generate CdTe/CdS intermediate products and an additional heat-up setup at relatively low temperature to overcoat the ZnS shells, the CdTe/CdS/ZnS multishell structures were realized. The as-synthesized CdTe/CdS/ZnS core/shell/shell quantum dots are characterized by photoluminescence spectra, X-ray diffraction (XRD, energy-dispersive X-ray spectra (EDS, transmission electron microscopy (TEM, and high-resolution transmission electron microscopy (HRTEM. Fluorescence and XRD results confirm that the obtained quantum dots have a core/shell/shell structure. It shows the highest quantum yield above 45% when compared to the rhodamine 6G. The core/shell/shell QDs were more stable via the oxidation experiment by H2O2.

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

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)

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

Geology, S-Pb isotopes, and 40Ar/39Ar geochronology of the Zhaxikang Sb-Pb-Zn-Ag deposit in Southern Tibet: implications for multiple mineralization events at Zhaxikang

Science.gov (United States)

Sun, Xiang; Zheng, Youye; Pirajno, Franco; McCuaig, T. Campbell; Yu, Miao; Xia, Shenlan; Song, Qingjie; Chang, Huifang

2018-03-01

Several Au, Sb, Sb-Au, Pb-Zn, and Sb-Pb-Zn-Ag deposits are present throughout the North Himalaya in southern Tibet, China. The largest Sb-Pb-Zn-Ag deposit is Zhaxikang (18 Mt at 0.6 wt% Sb, 2.0 wt% Pb, 3.5 wt% Zn, and 78 g/t Ag). Zhaxikang veins are hosted within N-S trending faults, which crosscut the Early-Middle Jurassic Ridang Formation consisting of shale interbedded with sandstone and limestone deposited on a passive continental margin. Ore paragenesis indicates that Zhaxikang mineralization occurred in two main phases composed of six total stages. The initial phase was characterized by assemblages of fine-grained Mn-Fe carbonate + arsenopyrite + pyrite + sphalerite (stage 1), followed by relatively coarse-grained Mn-Fe carbonate + Fe-rich sphalerite + galena + pyrite (stage 2). The second phase was marked by assemblages of quartz + pyrite + Fe-poor sphalerite and Ag-rich galena + tetrahedrite + sericite (stage 3), quartz + Sb-Pb sulfosalt minerals mainly composed of boulangerite and jamesonite (stage 4), quartz + stibnite ± cinnabar (stage 5), and quartz ± calcite (stage 6). Sulfides of stage 2 have δ34SV-CDT of 8.4-12.0‰, 206Pb/204Pb ratios of 19.648 to 19.659, 207Pb/204Pb ratios of 15.788 to 15.812, and 208Pb/204Pb ratios of 40.035 to 40.153. Sulfides of stage 3 have similar δ34SV-CDT of 6.1-11.2‰ and relatively more radiogenic lead isotopes (206Pb/204Pb = 19.683-19.792). Stage 4 Sb-Pb sulfosalt minerals have δ34SV-CDT of 5.0-7.2‰ and even more radiogenic lead (206Pb/204Pb = 19.811-19.981). By contrast, stibnite of stage 5 has δ34SV-CDT of 4.5-7.8‰ and less radiogenic lead (206Pb/204Pb = 18.880-18.974). Taken together with the geological observations that the Pb-Zn-bearing Mn-Fe carbonate veins were crosscut by various types of quartz veins, sphalerite and galena of stage 2 underwent dissolution and remobilization, and that Sb-Pb(-Fe) sulfosalts formed at the expense of Pb from stage 2 galena and of Fe from stage 2 sphalerite, we argue that

Improving conversion efficiency of CdS quantum dots-sensitized TiO{sub 2} nanotube arrays by doping with Zn{sup 2+} and decorating with ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Chen, Chong, E-mail: chongchen@henu.edu.cn [Henan Key Laboratory of Photovoltaic Materials, Henan University, Kaifeng 475004 (China); School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Wang, Lei; Li, Fumin; Ling, Lanyu [Henan Key Laboratory of Photovoltaic Materials, Henan University, Kaifeng 475004 (China); School of Physics and Electronics, Henan University, Kaifeng 475004 (China)

2014-08-01

The Zn-doped TiO{sub 2} nanotube arrays (TNTs) decorated with ZnO nanoparticles have been prepared via electrochemical anodization and immersing method. Furthermore, the CdS quantum dots (QDs) were deposited on the prepared Zn-doped TNTs-ZnO thin films by chemical bath deposition (CBD) method to fabricate the CdS QDs-sensitized Zn-doped TNTs-ZnO photoelectrodes. The nanostructure, morphology, optical properties and electrochemical properties of the CdS/Zn-doped TNTs-ZnO photoelectrode with comparison to those of the CdS/TNTs photoelectrodes were investigated. It has been found that the Zn-doped TNTs-ZnO photoelectrodes significantly increased the UV–vis light absorption of the CdS/Zn-doped TNTs-ZnO photoelectrodes and reduced the charge recombination at the surfaces of the CdS/Zn-doped TNTs-ZnO photoelectrodes. As a consequence, when the Zn-doped TNTs-ZnO film was adopted instead of the plain TNTs film, the light-chemical energy conversion efficiency of the CdS/Zn-doped TNTs-ZnO photoelectrode was much improved compared with the CdS/TNTs photoelectrode. A maximum energy conversion efficiency achieved for the CdS/Zn-doped TNTs-ZnO photoelectrode is 3.86%, which is a 17% improvement compared with the maximum energy conversion efficiency of 3.29% achieved for the CdS/TNTs photoelectrodes. - Highlights: • The CdS/Zn-doped TNTs-ZnO photoelectrodes were synthesized. • The optical properties and photochemical properties were investigated. • The energy conversion efficiency depends on the Zn doping concentration. • The energy conversion efficiency was improved by the Zn doping.

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).

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

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.

Synthesis and optical properties of CdS/ZnS coreshell nanoparticles

International Nuclear Information System (INIS)

Saraswathi Amma, B.; Manzoor, K.; Ramakrishna, K.; Pattabi, Manjunatha

2008-01-01

Synthesis and optical properties of manganese (Mn 2+ )-doped, polyvinyl pyrrolidone (PVP)-capped cadmium sulphide (CdS) nanoparticles coated with zinc sulphide (ZnS) are reported. Colloidal solution of Mn 2+ -doped CdS nanoparticles capped with PVP is synthesized using methanol as solvent. PVP is used to control the particle size and to prevent agglomeration. Mn 2+ doping is expected to help in increasing the CdS band edge photoluminescence (PL) emission. Addition of zinc nitrate and sodium sulphide alternately to the Mn 2+ -doped, PVP-stabilized CdS colloid led to the formation of ZnS-coated CdS coreshell nanoparticles. Photoluminescence emission spectra recorded for (CdS-PVP)Mn nanoparticles showed two emission peaks, one at 416 nm and the other weaker peak at 586 nm which is attributed to Mn 2+ emission. Intensity of Mn 2+ peak increased with increase in the Mn 2+ content. Mn 2+ emission disappears when ZnS is coated over the CdS core, resulting in pure CdS band edge emission

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.

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.

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

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)

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

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)

A review of Pb-Sb(As-S, Cu(Ag-Fe(Zn-Sb(As-S, Ag(Pb-Bi(Sb-S and Pb-Bi-S(Te sulfosalt systems from the Boranja orefield, West Serbia

Directory of Open Access Journals (Sweden)

Radosavljević Slobodan A.

2016-01-01

Full Text Available Recent mineralogical, chemical, physical, and crystallographic investigations of the Boranja orefield showed very complex mineral associations and assemblages where sulfosalts have significant role. The sulfosalts of the Boranja orefield can be divided in four main groups: (i Pb-Sb(As-S system with ±Fe and ±Cu; (ii Cu(Ag-Fe(Zn-Sb(As-S system; (iii Ag(Pb-Bi(Sb-S; (iv and Pb-Bi-S(Te system. Spatially, these sulfosalts are widely spread, however, they are the most abundant in the following polymetallic deposits and ore zones: Cu(Bi-FeS Kram-Mlakva; Pb(Ag-Zn-FeS2 Veliki Majdan (Kolarica-Centralni revir-Kojići; Sb-Zn-Pb-As Rujevac; and Pb-Zn-FeS2-BaSO4 Bobija. The multi stage formation of minerals, from skarnhydrothermal to complex hydrothermal with various stages and sub-stages has been determined. All hydrothermal stages and sub-stages of various polymetallic deposits and ore zones within the Boranja orefield are followed by a variety of sulfosalts. [Projekat Ministarstva nauke Republike Srbije, br. OI-176016: Magmatism and geodynamics of the Balkan Peninsula from Mesozoic to present day: Significance for the formation of metallic and non-metallic mineral deposits

CdSe@ZnS nanocomposites prepared by a mechanochemical route: No release of Cd{sup 2+} ions and negligible in vitro cytotoxicity

Energy Technology Data Exchange (ETDEWEB)

Baláž, Peter, E-mail: balaz@saske.sk [Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04353 Košice (Slovakia); Sayagués, Maria Jesús, E-mail: mjsayagues@icmse.csic.es [Institute of Materials Science of Sevilla CSIC, Américo Vespucio 49, 41092 Sevilla (Spain); Baláž, Matej, E-mail: balazm@saske.sk [Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04353 Košice (Slovakia); Zorkovská, Anna, E-mail: zorkovska@saske.sk [Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04353 Košice (Slovakia); Hronec, Pavol, E-mail: hronec.pavol@gmail.com [Slovak University of Technology, Faculty of Electrical Engineering and Information Technology, Iľkovičova 3, 81219 Bratislava (Slovakia); Kováč, Jaroslav, E-mail: jaroslav_kovac@stuba.sk [Slovak University of Technology, Faculty of Electrical Engineering and Information Technology, Iľkovičova 3, 81219 Bratislava (Slovakia); Kováč, Jaroslav, E-mail: jaroslav.kovac@stuba.sk [Slovak University of Technology, Faculty of Electrical Engineering and Information Technology, Iľkovičova 3, 81219 Bratislava (Slovakia); Dutková, Erika, E-mail: dutkova@saske.sk [Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04353 Košice (Slovakia); Mojžišová, Gabriela, E-mail: gabriela.mojzisova@upjs.sk [P. J. Šafárik University, Faculty of Medicine, Trieda SNP 1, 04011 Košice (Slovakia); and others

2014-01-01

Graphical abstract: - Highlights: • CdSe@ZnS nanocomposites were produced by milling. • Negligible cadmium leakage was observed. • No toxicity against living cells was documented. • The material is suitable for biological imaging. - Abstract: CdSe@ZnS nanocomposites have been prepared by a two-step solid state mechanochemical synthesis. CdSe prepared from Cd and Se elements in the first step was mixed with zinc acetate and sodium sulphide in the second step of milling to prepare a CdSe@ZnS nanocomposite. In the third step, the obtained nanocomposite was coated with L-cysteine to prepare a biocompatible system. The crystallite size of the new type of nanocomposite was 20–35 nm for cubic CdSe and 3–8 nm for hexagonal ZnS as calculated from XRD, TEM and SEM data. The synthesised samples show good crystallinity and have been tested for dissolution and cytotoxicity. The dissolution of cadmium from CdSe@ZnS was less than 0.05 μg mL{sup −1}, whereas a value of 0.8 μg mL{sup −1} was measured for CdSe alone. The binding of ZnS with CdSe in the nanocomposite practically eliminated the release of cadmium into solution. As a consequence, a very low cytotoxic activity has been evidenced for CdSe@ZnS. The nanocomposites coated with L-cysteine have a great potential as fluorescent labels in biomedical engineering.

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...

Role of ZnO photoanode nanostructures and sensitizer deposition approaches on the photovoltaic properties of CdS/CdSe and CdS1-xSex quantum dot-sensitized solar cells

Science.gov (United States)

Şişman, İlkay; Tekir, Oktay; Karaca, Hüseyin

2017-02-01

Hierarchical bundle-like ZnO nanorod arrays (BNRs) were synthesized by a one-pot hydrothermal method based on two consecutive temperature steps for cascade CdS/CdSe and ternary CdS1-xSex alloy quantum dot-sensitized solar cells (QDSSCs) as photoanode. The CdS/CdSe and CdS1-xSex QDs were deposited on the surface of the ZnO BNRs by conventional and modified successive ionic-layer adsorption and reaction (SILAR) methods, respectively. Using the ZnO BNRs/CdS/CdSe photoanode, the power conversion efficiency reaches 2.08%, which is 1.8 times higher than that of pristine ZnO nanorods/CdS/CdSe photoanode, while by applying ZnO BNRs/CdS1-xSex, the power conversion efficiency improves 2.52%. The remarkably improved photovoltaic performance is mainly derived from the bundle-like nanorod arrays structure, which increases the QDs loading amount and the scattering effect for light absorption, and the appropriate conduction band energy, sufficient Se amount and well coverage of the ternary CdS1-xSex QDs result in enhanced photogenerated electron injection, high light absorption and reduced recombination, respectively. As a result, ZnO BNRs/CdS1-xSex combination can significantly improve performance of QDSSCs.

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.