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Sample records for extracted metals sem

  1. Assessment of metal species in river Ganga sediment at Varanasi, India using sequential extraction procedure and SEM-EDS.

    Science.gov (United States)

    Pandey, Mayank; Pandey, Ashutosh Kumar; Mishra, Ashutosh; Tripathi, B D

    2015-09-01

    Aim of the present study was to assess impact of urban drains over river water and sediments by physico-chemical and metal analysis. Metal speciation (Sequential Extraction Procedure) and elemental composition analysis (SEM-EDS) was used to quantify metal pollution load in river sediments. Metal speciation analysis showed dominance of available and labile fractions of all heavy metals (Cr, Ni, Cu, Zn, Cd and Pb) except Mn and Fe which were dominant in residual forms. Cluster analysis (CA), Principal Components Analysis (PCA) and Partial Least Square Regression (PLSR) were applied as source receptor modeling for pollutants. Results classified river stretch into three zones i.e. moderately, severely and extremely polluted, on the basis of pollutant concentration released from anthropogenic sources. SEM-EDS study revealed the elemental composition percentage in river sediments. Pollution Load Index (PLI) varied from 1.8 (S1)-3.9 (S15). The Geo accumulation index (GAI) was found highest for Cd (6.88-8.97) and Pb (2.41-3.24).

  2. Bioavailability assessment of toxic metals using the technique "acid-volatile sulfide (AVS)-simultaneously extracted metals (SEM)" in marine sediments collected in Todos os Santos Bay, Brazil.

    Science.gov (United States)

    Silva, Jucelino B; Nascimento, Rodrigo A; de Oliva, Sergio T; de Oliveira, Olívia M C; Ferreira, Sergio L C

    2015-10-01

    This paper reports the bioavailability of the metals (cadmium, copper, zinc, lead, and nickel) in sediment samples collected in seven stations from the São Paulo Estuary, Todos os Santos Bay, Brazil. The bioavailability was determined by employing the technique "acid-volatile sulfide (AVS) and simultaneously extracted metal (SEM)". The elements cadmium, copper, lead, and zinc were determined using differential pulse anodic stripping voltammetry (DPASV), while nickel was quantified utilizing electrothermal atomic absorption spectrometry (ET AAS). The accuracy of these methods was confirmed using a certified reference material of estuarine sediment (NIST 1646). The sulfide was quantified using potentiometry with selective electrode and the organic matter determination employing an indirect volumetric method using potassium dichromate and iron(II) sulfate solutions. The bioavailability of the metals was estimated by relationship between the concentration of AVS and the sum of the concentrations of the simultaneously extracted metalsSEM), considering a significant toxicity when (ΣSEM)/(AVS) is higher than 1. The bioavailability values in the seven stations studied varied from 0.93 to 1.31 (June, 2014) and from 0.34 to 0.58 (September, 2014). These results demonstrated a critical condition of toxicity (bioavailability >1) in six of the seven sediment samples collected during the rainy season (June, 2014). In the other period (September, 2014), the bioavailability was always lower than 1 for all sediment samples collected in the seven stations. The individual values of the concentrations of the five metals were compared with the parameters PEL (probable effects level) and TEL (threshold effects level), which are commonly employed for characterization of ecological risk in environmental systems. This comparison revealed that all metals have concentrations lower than the PEL and only zinc and lead in some stations have contents higher than the TEL. The

  3. Trace metals in floodplain lake sediments : SEM/AVS as indicator of bioavailability and ecological effects

    NARCIS (Netherlands)

    Griethuysen, van C.

    2006-01-01

    This thesis addresses the geochemical aspects of AVS (Acid Volatile Sulfide) and SEM (Simultaneously Extracted Metals) in floodplain lake sediment, its spatial distribution in floodplain lakes and dynamics over time, the link with effects on single species (bioassays), as well as the impact of

  4. FIB/SEM cell sectioning for intracellular metal granules characterization

    Science.gov (United States)

    Milani, Marziale; Brundu, Claudia; Santisi, Grazia; Savoia, Claudio; Tatti, Francesco

    2009-05-01

    Focused Ion Beams (FIBs) provide a cross-sectioning tool for submicron dissection of cells and subcellular structures. In combination with Scanning Electron Microscope (SEM), FIB provides complementary morphological information, that can be further completed by EDX (Energy Dispersive X-ray Spectroscopy). This study focus onto intracellular microstructures, particularly onto metal granules (typically Zn, Cu and Fe) and on the possibility of sectioning digestive gland cells of the terrestrial isopod P. scaber making the granules available for a compositional analysis with EDX. Qualitative and quantitative analysis of metal granules size, amount and distribution are performed. Information is made available of the cellular storing pattern and, indirectly, metal metabolism. The extension to human level is of utmost interest since some pathologies of relevance are metal related. Apart from the common metal-overload-diseases (hereditary hemochromatosis, Wilson's and Menkes disease) it has been demonstrated that metal in excess can influence carcinogenesis in liver, kidney and breast. Therefore protocols will be established for the observation of mammal cells to improve our knowledge about the intracellular metal amount and distribution both in healthy cells and in those affected by primary or secondary metal overload or depletion.

  5. The risk assessment of heavy metals in Futian mangrove forest sediment in Shenzhen Bay (South China) based on SEM-AVS analysis.

    Science.gov (United States)

    Chai, Minwei; Shen, Xiaoxue; Li, Ruili; Qiu, Guoyu

    2015-08-15

    The risks of heavy metal in Futian mangrove forest sediment were assessed using the acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) methods. The results indicated that AVS distributions were more variable than the SEM distributions at all 16 sampling sites. The positive correlation between AVS and SEM indicated that their similar formative and existing conditions and that AVS acted as an important carrier for SEM. The major SEM component was Zn (69.7.3-94.2%), whereas the Cd contribution (the most toxic metal present) to SEM was no more than 1%. The possible adverse effects caused by heavy metals at ten sampling sites may be due to higher levels of SEMs, rather than AVSs. The total organic carbon (TOC) was an important metal-binding phase in the sediments. Taking into account the TOC concentration, there were no adverse effects due to heavy metals in any of the Futian mangrove forest sediments.

  6. FIB/SEM and SEM/EDS microstructural analysis of metal-ceramic and zirconia-ceramic interfaces.

    Science.gov (United States)

    Massimi, F; Merlati, G; Sebastiani, M; Battaini, P; Menghini, P; Bemporad, E

    2012-01-10

    Recently introduced FIB/SEM analysis in microscopy seems to provide a high-resolution characterization of the samples by 3D (FIB) cross-sectioning and (SEM) high resolution imaging. The aim of this study was to apply the FIB/SEM and SEM/EDS analysis to the interfaces of a metal-ceramic vs. two zirconia-ceramic systems. Plate samples of three different prosthetic systems were prepared in the dental lab following the manufacturers' instructions, where metal-ceramic was the result of a ceramic veneering (porcelain-fused-to-metal) and the two zirconia-ceramic systems were produced by the dedicated CAD-CAM procedures of the zirconia cores (both with final sintering) and then veneered by layered or heat pressed ceramics. In a FIB/SEM equipment (also called DualBeam), a thin layer of platinum (1 μm) was deposited on samples surface crossing the interfaces, in order to protect them during milling. Then, increasingly deeper trenches were milled by a focused ion beam, first using a relatively higher and later using a lower ion current (from 9 nA to 0.28 nA, 30KV). Finally, FEG-SEM (5KV) micrographs (1000-50,000X) were acquired. In a SEM the analysis of the morphology and internal microstructure was performed by 13KV secondary and backscattered electrons signals (in all the samples). The compositional maps were then performed by EDS probe only in the metal-ceramic system (20kV). Despite the presence of many voids in all the ceramic layers, it was possible to identify: (1) the grain structures of the metallic and zirconia substrates, (2) the thin oxide layer at the metal-ceramic interface and its interactions with the first ceramic layer (wash technique), (3) the roughness of the two different zirconia cores and their interactions with the ceramic interface, where the presence of zirconia grains in the ceramic layer was reported in two system possibly due to sandblasting before ceramic firing.

  7. SEM evaluation of metallization on semiconductors. [Scanning Electron Microscope

    Science.gov (United States)

    Fresh, D. L.; Adolphsen, J. W.

    1974-01-01

    A test method for the evaluation of metallization on semiconductors is presented and discussed. The method has been prepared in MIL-STD format for submittal as a proposed addition to MIL-STD-883. It is applicable to discrete devices and to integrated circuits and specifically addresses batch-process oriented defects. Quantitative accept/reject criteria are given for contact windows, other oxide steps, and general interconnecting metallization. Figures are provided that illustrate typical types of defects. Apparatus specifications, sampling plans, and specimen preparation and examination requirements are described. Procedures for glassivated devices and for multi-metal interconnection systems are included.

  8. Assessment of heavy metals pollution using AVS-SEM and fractionation techniques in Edku Lagoon sediments, Mediterranean Sea, Egypt.

    Science.gov (United States)

    El Zokm, Gehan M; Okbah, Mohamed A; Younis, Alaa M

    2015-01-01

    A method is presented to evaluate the fractionation of metals (Fe, Zn, Cu, Pb, Cd and Ni), acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) in Edku lagoon sediments. Thirteen sediment samples were collected from the study area in the period of 2010-2011 to assess the potential bioavailability and toxicity of the selected metals. According to classification of the Interim Sediment Quality Quidelines (ISQG), five stations near the drains exhibited 10% toxic probability. The high AVS and low ∑SEM ranges in Summer were identified as 6-138 and 0.86-3.3 µmol g(-1) dry wet, respectively which are referring to the low mobility of heavy metals in this season and vice versa for winter (2.5-23.9 and 1.16-3.82 µmol g(-1) dry wet, respectively). According to the evaluation of USEPA, all sediment samples showed ∑SEM/AVS < 1 and ΣSEM-AVS < 0 and this indicates that Edku lagoon sediments didn't cause any adverse effects. Meanwhile, the calculations of the global contamination factor (GCF) and the individual contamination factors (ICF) using fractionation technique gave values of 111.644 and 84.555 in El Bosily drain and station 1 near the cages of fish farm, respectively due to possible contamination. Interestingly, the collected data refer that the mobility and bioavailability of heavy metals in Edku lagoon sediments posed a low risk of adverse biological effects due to cadmium, copper, lead, nickel and zinc in all evaluated stations.

  9. Titanium metal: extraction to application

    Energy Technology Data Exchange (ETDEWEB)

    Gambogi, Joseph (USGS, Reston, VA); Gerdemann, Stephen J.

    2002-09-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium. In this paper, we discuss all aspects of the titanium industry from ore deposits through extraction to present and future applications. The methods of both primary (mining of ore, extraction, and purification) and secondary (forming and machining) operations will be analyzed. The chemical and physical properties of titanium metal will be briefly examined. Present and future applications for titanium will be discussed. Finally, the economics of titanium metal production also are analyzed as well as the advantages and disadvantages of various alternative extraction methods.

  10. OpenCV-Based Nanomanipulation Information Extraction and the Probe Operation in SEM

    Directory of Open Access Journals (Sweden)

    Dongjie Li

    2015-02-01

    Full Text Available Aimed at the established telenanomanipulation system, the method of extracting location information and the strategies of probe operation were studied in this paper. First, the machine learning algorithm of OpenCV was used to extract location information from SEM images. Thus nanowires and probe in SEM images can be automatically tracked and the region of interest (ROI can be marked quickly. Then the location of nanowire and probe can be extracted from the ROI. To study the probe operation strategy, the Van der Waals force between probe and a nanowire was computed; thus relevant operating parameters can be obtained. With these operating parameters, the nanowire in 3D virtual environment can be preoperated and an optimal path of the probe can be obtained. The actual probe runs automatically under the telenanomanipulation system's control. Finally, experiments were carried out to verify the above methods, and results show the designed methods have achieved the expected effect.

  11. Metals Separation by Liquid Extraction.

    Science.gov (United States)

    Malmary, G.; And Others

    1984-01-01

    As part of a project focusing on techniques in industrial chemistry, students carry out experiments on separating copper from cobalt in chloride-containing aqueous solution by liquid extraction with triisoctylamine solvent and search the literature on the separation process of these metals. These experiments and the literature research are…

  12. Recent trends in metals extraction

    Directory of Open Access Journals (Sweden)

    Regel-Rosocka, M.

    2013-08-01

    Full Text Available After near 70 years of practical usage, solvent extraction is a perfectly mastered technique of separation, widely used on an industrial scale for the separation of metals mainly from raw materials. However, currently, in the era of depleting natural resources and increasingly less accessible deposits, environmental restrictions, etc., an increasing interest, both from social and economical constrains, is being directed at the extraction of metals from the secondary sources (such as batteries, electronic scrap. In many cases, solvent extraction, due to its operational characteristics, can be considered as the Best Available Technology for the purpose of separating multielemental metal solutions. This paper provides a brief overview of past achievements and present scenario of solvent extraction investigations and developments, describing some recently commissioned solvent extraction plants, whereas the Skorpion Zinc plant (Namibia for zinc extraction from raw materials and caesium removal from radioactive High Level Wastes (HLWs are told over in detail as case studies. The paper also presents some proposals for the use of liquid-liquid extraction to separate metal ions from secondary sources (e.g. cobalt from industrial waste streams. The review highlights the emerging use of ionic liquids as new extractants for metals, providing an insight into this exciting research field. Despite its detractors, solvent extraction has entered in force into XXI century as a leading separation technology for metals.Después de casi 70 años de uso práctico, la extracción líquido-líquido o extracción con disolventes es una técnica de separación muy evolucionada, utilizándose a escala industrial en el beneficio de metales obtenidos de diversas materias primas. Sin embargo, con el agotamiento de los recursos naturales y el aumento de depósitos minerales de más difícil acceso, restricciones medio ambientales, etc., ha aumentado el interés, tanto desde

  13. Application of SEM/EDS to environmental geochemistry of heavy metals

    Directory of Open Access Journals (Sweden)

    Mateja Gosar

    2009-06-01

    Full Text Available Heavy metals represent a ubiquitous constituent of the near-surface environment, present in widely varyingconcentrations that typically have little impact on human behaviour and health. However, the mining of metals anduse of these metals in industrial processes has produced significant anthropogenic inputs of metals to both localand global environments. As such, a rigorous overview of the current accumulation of heavy metals and knowledgeof mineralogy of heavy metal-bearing phases is important for understanding their stability, solubility, mobility,bioavailability and toxicity. These data are of fundamental importance for environmental risk assessment and evaluationof future scenarios. Since conventional geochemical analyses provide limited information, other analyticalmethods have to be utilized for the characterisation of heavy metal-bearing phases. Significant analytical methodfor identification and characterisation of heavy metals in environmental media is a scanning electron microscopecoupled with energy dispersive X-ray spectrometer (SEM/EDS, an apparatus for qualitative and semi-quantitative chemical analysis at microne level, newly introduced to Geological Survey of Slovenia. Use of SEM/EDS was already introduced to environmental studies world-wide. In Slovenia, SEM/EDS analyses of environmental media werefirstly carried out on the Meža River stream sediments and snow deposits from Ljubljana urban area.Heavy metal-bearing phases in the Meža River stream sediments were apportioned to three source areas: Mežica mining/smelting area (geogenic-technogenic origin, Ravne ironworks area (technogenic origin and the Meža River catchment area (geogenic origin, which corresponds to data obtained by conventional geochemical and multivariate statistical methods. Airborne particles, identified in urban snow deposits, were interpreted as geogenic particles, represented by fragments of heavy metal-bearing minerals, and technogenic particles that

  14. A kinetic approach to evaluate the association of acid volatile sulfide and simultaneously extracted metals in aquatic sediments

    NARCIS (Netherlands)

    Poot, A.; Meerman, E.; Gillissen, F.; Koelmans, A.A.

    2009-01-01

    The acid volatile sulfide (AVS) and simultaneously extracted metals (¿SEM) method is widely used for evaluating potential bioavailability of heavy metals in soil and sediment. It is also criticized, because the requirement that AVS and SEM metals (i.e., Cd, Cu, Ni, Pb, and Zn) are associated in the

  15. Charge dependent asphaltene adsorption onto metal substrate : electrochemistry and AFM, STM, SAM, SEM analysis

    Energy Technology Data Exchange (ETDEWEB)

    Batina, N.; Morales-Martinez, J. [Univ. Autonoma Metropolitana-Iztapalapa (Mexico). Lab. de Nanotecnologia e Ingenieria Molecular; Ivar-Andersen, S. [Technical Univ. of Denmark (Denmark). Dept. Hem. Eng; Lira-Galeana, C. [Inst. Mexicano del Petroleo, Lazaro (Mexico). Molecular Simulation Research Program; De la Cruz-Hernandez, W.; Cota-Araiza, L.; Avalos-Borja, M. [Univ. Nacional Autonoma de Mexico (Mexico)

    2008-07-01

    Asphaltenes have been identified as the main component of pipeline molecular deposits that cause plugging of oil wells. In this study, Atomic Force Microscopy (AFM), Scanning Tunneling Microscopy (STM), Scanning Auger Microprobe Spectroscopy (SAM) and Scanning Electron Microscopy (SEM) were used to characterized molecular deposits of Mexican crude oil and asphaltenes formed at a charged metal surface. The qualitative and quantitative characterization involved determining the size and shape of adsorbed molecules and aggregates, and the elemental analysis of all components in molecular films. Samples were prepared by electrolytic deposition under galvanostatic or potentiostatic conditions directly from the crude oil or asphaltene in toluene solutions. The study showed that the formation of asphaltene deposit depends on the metal substrate charge. Asphaltenes as well as crude oil readily adsorbed at the negatively charged metal surface. Two elements were present, notably carbon and sulfur. Their content ratio varied depending on the metal substrate charge.

  16. Spectral, XRD, SEM and biological activities of transition metal complexes of polydentate ligands containing thiazole moiety

    Science.gov (United States)

    Neelakantan, M. A.; Marriappan, S. S.; Dharmaraja, J.; Jeyakumar, T.; Muthukumaran, K.

    2008-11-01

    Metal complexes of o-vanillidene-2-aminobenzothiazole have been prepared and characterized by elemental and spectral (vibrational, electronic, 1H NMR and EPR) data as well as magnetic susceptibility measurements and thermo gravimetric analysis (TG/DTA). The low molar conductance values reveal the non-electrolytic nature of these complexes. The elemental analysis suggests that the stoichiometry to be 1:2 (metal:ligand). Magnetic susceptibility data coupled with electronic spectra suggest that two ligands coordinate to each metal atom by phenolic oxygen and imino nitrogen to form high spin octahedral complex with Co(II), Mn(II) and Ni(II). The fifth and sixth position of metal ion is satisfied with water molecules. The thermal behaviour (TG/DTA) of the synthesised complexes shows that the complexes loss water molecules in the first step followed by decomposition of the ligand. Spin Hamiltonian parameters predict a distorted tetrahedral geometry for the copper complex. XRD and SEM analysis provide the crystalline nature and the morphology of the metal complexes. The in vitro biological activity of the metal chelates is tested against the Gram positive bacteria ( Bacillus amyloliquifacians) and gram negative bacteria ( Pseudomonas species), fungus ( Aspergillus niger) and yeast ( Sacchromyces cereviaceae). Most of the metal chelates exhibited higher biological activities.

  17. Heavy metals extraction from anaerobically digested sludge

    NARCIS (Netherlands)

    Marchioretto, M.M.; Bruning, H.; Loan, N.T.P.; Rulkens, W.H.

    2002-01-01

    This paper reports on the chemical extraction efficiency in the removal of heavy metals from sludge from an activated-sludge system, which receives as influent both industrial and municipal wastewater. Utilizing a series of chemical extractants in a sequential order comprised the first phase of the

  18. Heavy metals extraction from anaerobically digested sludge

    NARCIS (Netherlands)

    Marchioretto, M.M.; Bruning, H.; Loan, N.T.P.; Rulkens, W.H.

    2002-01-01

    This paper reports on the chemical extraction efficiency in the removal of heavy metals from sludge from an activated-sludge system, which receives as influent both industrial and municipal wastewater. Utilizing a series of chemical extractants in a sequential order comprised the first phase of the

  19. Solvent extraction of metals with hydroxamic acids.

    Science.gov (United States)

    Vernon, F; Khorassani, J H

    1978-07-01

    Solvent extraction with hydroxamic acids has been investigated. with comparison of aliphatic and aromatic reagents for the extraction of iron, copper, cobalt and nickel. Caprylohydroxamic acid has been evaluated for use in extraction systems for titanium, vanadium, chromium, molybdenum and uranium, both in terms of acidity of aqueous phase and oxidation state of the metal. It has been established that caprylohydroxamic acid in 1-hexanol is a suitable extractant for the removal of titanium(IV), vanadium(V), chromium(VI), molybdenum(VI) and uranium(VI) from 6M hydrochloric acid.

  20. Growth profile and SEM analyses of Candida albicans and Escherichia coli with Hymenocallis littoralis (Jacq.) Salisb leaf extract.

    Science.gov (United States)

    Rosli, N; Sumathy, V; Vikneswaran, M; Sreeramanan, S

    2014-12-01

    Hymenocallis littoralis (Jacq.) Salisb (Melong kecil) commonly known as 'Spider Lily' is an herbaceous plant from the family Amaryllidaceae. Study was carried out to determine the effect of H. littoralis leaf extract on the growth and morphogenesis of two pathogenic microbes, Candida albicans and Escherichia coli. The leaf extract displayed favourable anticandidal and antibacterial activity with a minimum inhibition concentration (MIC) of 6.25 mg/mL. Time kill study showed both microbes were completely killed after treated with leaf extract at 20 h. Both microbes' cell walls were heavily ruptured based on scanning electron microscopy (SEM) analysis. The significant anticandidal and antibacterial activities showed by H. littoralis leaf extract suggested the potential antimicrobial agent against C. albicans and E. coli.

  1. Selective laser extraction of the Pt group metals

    Energy Technology Data Exchange (ETDEWEB)

    Fadeeva, S.; Krynetsky, B.; Prokhorov, A.; Zhidkov, A. [General Physics Institute, Russian Academy of Science, Moscow (Russian Federation)

    1995-11-15

    The interest to the platinum-group metals extraction from solutions, especially industry waste, is stimulated by their extraordinary chemical inert. The traditional chemical methods of the extraction are uneffective. Have been investigated process of the extraction of metal Pt-group from acid solutions. Discussed processes reduction of noble metals by resonance laser action.

  2. In situ SEM thermal fatigue of Al/graphite metal matrix composites

    Science.gov (United States)

    Zong, G. S.; Rabenberg, L.; Marcus, H. L.

    1990-01-01

    Several thermal fatigue-induced failure mechanisms are deduced for unidirectional graphite-reinforced 6061 Al-alloy MMCs subjected to in situ thermal cycling. These thermal cycling conditions are representative of MMC service cycles in aerospace environments, where thermal fatigue is primarily associated with changes in the stress states near the interfaces due to coefficient of thermal expansion mismatch between fiber and matrix. This in situ SEM thermal-cycling study clarified such factors affecting MMCs' thermal fatigue as local fiber content and distribution, void volume, fiber stiffness, thermal excursion magnitude, and number of thermal cycles. MMC microfailure modes in thermal fatigue have been deduced.

  3. Catalytic extraction processing of contaminated scrap metal

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, T.P.; Johnston, J.E.; Payea, B.M. [Molten Metal Technology, Inc., Waltham, MA (United States)] [and others

    1995-10-01

    The U.S. Department of Energy issued a Planned Research and Development Announcement (PRDA) in 1993, with the objective of identifying unique technologies which could be applied to the most hazardous waste streams at DOE sites. The combination of radioactive contamination with additional contamination by hazardous constituents such as those identified by the Resource Conservation and Recovery Act (RCRA) pose an especially challenging problem. Traditional remediation technologies are increasingly becoming less acceptable to stakeholders and regulators because of the risks they pose to public health and safety. Desirable recycling technologies were described by the DOE as: (1) easily installed, operated, and maintained; (2) exhibiting superior environmental performance; (3) protective of worker and public health and safety; (4) readily acceptable to a wide spectrum of evaluators; and (5) economically feasible. Molten Metal Technology, Inc. (MMT) was awarded a contract as a result of the PRDA initiative to demonstrate the applicability of Catalytic Extraction Processing (CEP), MMT`s proprietary elemental recycling technology, to DOE`s inventory of low level mixed waste. This includes DOE`s inventory of radioactively- and RCRA-contaminated scrap metal and other waste forms expected to be generated by the decontamination and decommissioning (D&D) of DOE sites.

  4. Supercritical Fluid Extraction of Metal Chelate: A Review.

    Science.gov (United States)

    Ding, Xin; Liu, Qinli; Hou, Xiongpo; Fang, Tao

    2017-03-04

    Supercritical fluid extraction (SFE), as a new green extraction technology, has been used in extracting various metal species. The solubilities of chelating agents and corresponding metal chelates are the key factors which influence the efficiency of SFE. Other main properties of them such as stability and selectivity are also reviewed. The extraction mechanisms of mainly used chelating agents are explained by typical examples in this paper. This is the important aspect of SFE of metal ions. Moreover, the extraction efficiencies of metal species also depend on other factors such as temperature, pressure, extraction time and matrix effect. The two main complexation methods namely in-situ and on-line chelating SFE are described in detail. As an efficient chelating agent, tributyl phosphate-nitric acid (TBP-HNO3) complex attracts much attention. The SFE of metal ions, lanthanides and actinides as well as organometallic compounds are also summarized. With the proper selection of ligands, high efficient extraction of metal species can be obtained. As an efficient sample analysis method, supercritical fluid chromatography (SFC) is introduced in this paper. Recently, the extraction method combining ionic liquids (ILs) with supercritical fluid has been becoming a novel technology for treating metal ions. The kinetics related to SFE of metal species is discussed with some specific examples.

  5. Metal scarcity and sustainability, analyzing the necessity to reduce the extraction of scarce metals

    NARCIS (Netherlands)

    Henckens, M. L C M; Driessen, P. P J; Worrell, E.

    2014-01-01

    There is debate whether or not further growth of metal extraction from the earth's crust will be sustainable in connection with geologic scarcity. Will future generations possibly face a depletion of specific metals? We study whether, for which metals and to what extent the extraction rate would nee

  6. Metal scarcity and sustainability, analyzing the necessity to reduce the extraction of scarce metals

    NARCIS (Netherlands)

    Henckens, M. L C M; Driessen, P. P J|info:eu-repo/dai/nl/069081417; Worrell, E.|info:eu-repo/dai/nl/106856715

    2014-01-01

    There is debate whether or not further growth of metal extraction from the earth's crust will be sustainable in connection with geologic scarcity. Will future generations possibly face a depletion of specific metals? We study whether, for which metals and to what extent the extraction rate would

  7. Automatically extracting sheet-metal features from solid model

    Institute of Scientific and Technical Information of China (English)

    刘志坚; 李建军; 王义林; 李材元; 肖祥芷

    2004-01-01

    With the development of modern industry,sheet-metal parts in mass production have been widely applied in mechanical,communication,electronics,and light industries in recent decades; but the advances in sheet-metal part design and manufacturing remain too slow compared with the increasing importance of sheet-metal parts in modern industry. This paper proposes a method for automatically extracting features from an arbitrary solid model of sheet-metal parts; whose characteristics are used for classification and graph-based representation of the sheet-metal features to extract the features embodied in a sheet-metal part. The extracting feature process can be divided for valid checking of the model geometry,feature matching,and feature relationship. Since the extracted features include abundant geometry and engineering information,they will be effective for downstream application such as feature rebuilding and stamping process planning.

  8. Automatically extracting sheet-metal features from solid model

    Institute of Scientific and Technical Information of China (English)

    刘志坚; 李建军; 王义林; 李材元; 肖祥芷

    2004-01-01

    With the development of modern industry, sheet-metal parts in mass production have been widely applied in mechanical, communication, electronics, and light industries in recent decades; but the advances in sheet-metal part design and manufacturing remain too slow compared with the increasing importance of sheet-metal parts in modern industry. This paper proposes a method for automatically extracting features from an arbitrary solid model of sheet-metal parts; whose characteristics are used for classification and graph-based representation of the sheet-metal features to extract the features embodied in a sheet-metal part. The extracting feature process can be divided for valid checking of the model geometry, feature matching, and feature relationship. Since the extracted features include abundant geometry and engineering information, they will be effective for downstream application such as feature rebuilding and stamping process planning.

  9. Stone extraction balloon-guided repeat self-expanding metal stent placement

    Institute of Scientific and Technical Information of China (English)

    Hyung; Hun; Kim; Jeong; Seop; Moon; Soo; Hyung; Ryu; Jung; Hwan; Lee; You; Sun; Kim

    2010-01-01

    Self-expanding metal stent (SEMS) placement offers safe and effective palliation in patients with upper gastrointestinal obstruction due to a malignancy. Well described complications of SEMS placement include tumor growth, obstruction, and stent migration. SEMS occlusions are treated by SEMS redeployment, argon plasma coagulation application, balloon dilation, and surgical bypass. At our center, we usually place the second SEMS into the first SEMS if there is complete occlusion by the tumor. We discovered a...

  10. Extraction of Nanostructured Metal Oxides from the Furnace Dust for the Realization of Low Cost Solar Applications

    Science.gov (United States)

    Girisun, T. C. Sabari; Babeela, C.; Vidhya, V.

    This article reports the simple one step process for the extraction of nanostructured metal oxides from the industrial waste (EOFD) for the realization of low cost solar applications. By hydrothermal technique with NaOH and H2SO4, valuable metals were obtained in the form of metal oxides. The identification of compounds and structural characterization were carried out through XRD and SEM analysis. Thus the metal oxides derived could be helpful to reduce the burden on the environment from the electric oil furnace dust, increase the development of the source nano material and reduce the cost of raw materials for solar cell applications.

  11. Review of Biohydrometallurgical Metals Extraction from Polymetallic Mineral Resources

    OpenAIRE

    Watling, Helen R.

    2014-01-01

    This review has as its underlying premise the need to become proficient in delivering a suite of element or metal products from polymetallic ores to avoid the predicted exhaustion of key metals in demand in technological societies. Many technologies, proven or still to be developed, will assist in meeting the demands of the next generation for trace and rare metals, potentially including the broader application of biohydrometallurgy for the extraction of multiple metals from low-grade and com...

  12. Extraction of precious metals from technogenic placers of primorye

    Institute of Scientific and Technical Information of China (English)

    Molchanov; V.; P.; Medkov; M.; A.; Belobeletskaya; M.; B.; Medvedev; E.; I.

    2005-01-01

    Intensive development of gold placer deposits in the South Far East of Russia has produced numerous technogenic placers (concentration dump tailings) that contain fine free and bound gold and the platinum group metals. The secondary processing of these technogenic placers makes it possible to extract the whole set of precious metals from the concentration tailings.The authors have elaborated the low-waste technology of extraction of useful components using the methods of gravitation, magnetic and electromagnetic separation, hydrometallurgy, and extraction. Usually, precious metals are leached with cyanide solutions that significantly deteriorate the ecological situation. Instead of them we propose to use thiocarbamide, thiocyanate, and mixed thiocarbamide and thiocyanate solutions in the process of utilization of the technogenic placers. Introduction of thiocyanate ions into the thiocarbamide leaching solutions increases the indices of gold extraction into a leaching solution. Efficiency of the precious metal extraction into leaching solutions is 94 %- 96 %.Our investigations showed that liquid extraction of gold and silver from the leaching solutions permits the precious metals to be extracted with additional separation from admixtures and essential decrease of specific thiocarbamide consumption. Comparatively inexpensive tributyl phosphate and diphenyl thiourea that are manufactured in production quantities, are used as extragents.Utilization of the technogenic placers of Primorye will produce the raw material for repeated extraction of precious metals and will be favorable for the ecological situation in the populous districts of the region where the placers exist.

  13. Extraction of heavy metals from soils using biodegradable chelating agents.

    Science.gov (United States)

    Tandy, Susan; Bossart, Karin; Mueller, Roland; Ritschel, Jens; Hauser, Lukas; Schulin, Rainer; Nowack, Bernd

    2004-02-01

    Metal pollution of soils is widespread across the globe, and the clean up of these soils is a difficulttask. One possible remediation technique is ex-situ soil washing using chelating agents. Ethylenediaminetetraacetic acid (EDTA) is a very effective chelating agent for this purpose but has the disadvantage that it is quite persistent in the environment due to its low biodegradability. The aim of our work was to investigate the biodegradable chelating agents [S,S]-ethylenediaminedisuccinic acid (EDDS), iminodisuccinic acid (IDSA), methylglycine diacetic acid (MGDA), and nitrilotriacetic acid (NTA) as potential alternatives and compare them with EDTA for effectiveness. Kinetic experiments showed for all metals and soils that 24 h was the optimum extraction time. Longer times only gave minor additional benefits for heavy metal extraction but an unwanted increase in iron mobilization. For Cu at pH 7, the order of the extraction efficiency for equimolar ratios of chelating agent to metal was EDDS > NTA> IDSA > MGDA > EDTA and for Zn it was NTA > EDDS > EDTA >MGDA > IDSA. The comparatively low efficiency of EDTA resulted from competition between the heavy metals and co-extracted Ca. For Pb the order of extraction was EDTA > NTA >EDDS due to the much stronger complexation of Pb by EDTA compared to EDDS. At higher concentration of complexing agent, less difference between the agents was found and less pH dependence. There was an increase in heavy metal extraction with decreasing pH, but this was offset by an increase in Ca and Fe extraction. In sequential extractions EDDS extracted metals almost exclusively from the exchangeable, mobile, and Mn-oxide fractions. We conclude that the extraction with EDDS at pH 7 showed the best compromise between extraction efficiency for Cu, Zn, and Pb and loss of Ca and Fe from the soil.

  14. Metal Concentrations in Soil Paste Extracts as Affected by Extraction Ratio

    Directory of Open Access Journals (Sweden)

    Filip M.G. Tack

    2002-01-01

    Full Text Available Saturated paste extracts are sometimes used to estimate metal levels in the soil solution. To assess the significance of heavy-metal concentrations measured in saturation extracts, soil paste extracts were prepared with distilled water in amounts ranging from 60–200% of the moisture content at saturation. Trace metals behaved as if a small pool consistently was dissolved independent of the extraction ratio applied. Metal concentrations in the solution hence were not buffered by the solid phase, but the observed behaviour would allow the estimation of metal concentrations in the soil solution as a function of moisture content. The behaviour of iron and manganese suggested that some microbial reduction occurred. The intensity increased with increasing extraction ratio but not to the extent of affecting dissolution of trace elements.

  15. Solid-liquid solvent extraction of metal ions

    Institute of Scientific and Technical Information of China (English)

    Bo Peng; Haiyan Fan; Jinzhang Gao

    2003-01-01

    An overview of extraction of some trace metal ions using molten solvent (low melting substance) during last two decadesis presented. The development of this technique since its inception is briefly traced. The comparison of extraction efficiency, thermo-dynamics and kinetics mainly involving extraction of rare earth ions between molten solvent extraction at high temperature and usualliquid-liquid extraction at room temperature are discussed in detail. The various parameters obtained from the previous and presentstudies such as equilibrium extraction constant Kex, pH1/2, thermodynamic and kinetic data are displayed in tabular form. Finally, thecurrent demands, disadvantages and future prospects are also evaluated.

  16. Estimating the extractability of potentially toxic metals in urban soils: A comparison of several extracting solutions

    Energy Technology Data Exchange (ETDEWEB)

    Madrid, F. [Instituto de Recursos Naturales y Agrobiologia de Sevilla (CSIC), Apartado 1052, 41080 Sevilla (Spain); Reinoso, R. [Instituto de Recursos Naturales y Agrobiologia de Sevilla (CSIC), Apartado 1052, 41080 Sevilla (Spain); Florido, M.C. [Departamento de Cristalografia, Mineralogia y Quimica Agricola, Universidad de Sevilla, Avda. Reina Mercedes, s/n, 41012 Sevilla (Spain); Diaz Barrientos, E. [Instituto de Recursos Naturales y Agrobiologia de Sevilla (CSIC), Apartado 1052, 41080 Sevilla (Spain); Ajmone-Marsan, F. [DI.VA.P.R.A., Chimica Agraria, Universita di Torino, Via Leonardo da Vinci, 44, 10095 Grugliasco, Torino (Italy); Davidson, C.M. [Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, Scotland (United Kingdom); Madrid, L. [Instituto de Recursos Naturales y Agrobiologia de Sevilla (CSIC), Apartado 1052, 41080 Sevilla (Spain)]. E-mail: madrid@irnase.csic.es

    2007-06-15

    Metals released by the extraction with aqua regia, EDTA, dilute HCl and sequential extraction (SE) by the BCR protocol were studied in urban soils of Sevilla, Torino, and Glasgow. By multivariate analysis, the amounts of Cu, Pb and Zn liberated by any method were statistically associated with one another, whereas other metals were not. The mean amounts of all metals extracted by HCl and by SE were well correlated, but SE was clearly underestimated by HCl. Individual data for Cu, Pb and Zn by both methods were correlated only if each city was considered separately. Other metals gave poorer relationships. Similar conclusions were reached comparing EDTA and HCl, with much lower values for EDTA. Dilute HCl extraction cannot thus be recommended for general use as alternative to BCR SE in urban soils. - Dilute HCl extraction is tested as an alternative to the BCR sequential extraction in urban soils.

  17. Empirical modeling of heavy metal extraction by EDDS from single-metal and multi-metal contaminated soils.

    Science.gov (United States)

    Yip, Theo C M; Tsang, Daniel C W; Ng, Kelvin T W; Lo, Irene M C

    2009-01-01

    The effectiveness of using biodegradable EDDS (S,S-ethylenediaminedisuccinic acid) for metal extraction has drawn increasing attention in recent years. In this study, an empirical model, which utilized the initial metal distribution in soils and a set of parameter values independently determined from sequential extraction, was developed for estimating the time-dependent heavy metal extraction by EDDS from single-metal and multi-metal contaminated soils. The model simulation provided a satisfactory description of the experimental results of the 7-d extraction kinetics of Cu, Zn, and Pb in both artificially contaminated and field-contaminated soils. Thus, independent and prior assessment of extraction efficiency would be available to facilitate the engineering applications of EDDS. Furthermore, a simple empirical equation using the initial metal distribution was also proposed to estimate the extraction efficiency at equilibrium. It was found that, for the same type of soils, higher extraction efficiency was achieved in multi-metal contaminated soils than in single-metal contaminated soils. The differences were 4-9%, 9-16%, and 21-31% for Cu, Zn, and Pb, respectively, probably due to the larger proportion of exchangeable and carbonate fractions of sorbed Zn and Pb in multi-metal contaminated soils. EDDS-promoted mineral dissolution, on the other hand, was more significant in multi-metal contaminated soils as a result of the higher EDDS concentration applied to the soils of higher total metal content.

  18. Removal of Heavy Metal Ions by using Calcium Carbonate Extracted from Starfish Treated by Protease and Amylase

    Directory of Open Access Journals (Sweden)

    Kyong-Soo Hong

    2011-10-01

    Full Text Available CaCO3 extracted from starfish by using the commercial protein lyase having α-amylase, β-amylase, and protease is applied to remove heavy metal ions. The extracted CaCO3 shows excellent characteristics in removing heavy metal ions such as Cu2+, Cd2+, Pb2+, and Cr6+ compared with conventional materials such as crab shells, sawdust, and activated carbon except for removing Zn2+. SEM images reveal that the extracted CaCO33 has a good morphology and porosity. We characterize the removal efficiencies of the extracted CaCO3 for the heavy metal ions according to the concentrations, pH, temperatures, and conditions of empty bed contact times.

  19. SOLVENT EXTRACTION PROCESS FOR SEPARATING ACTINIDE AND LANTHANIDE METAL VALUES

    Science.gov (United States)

    Hildebrandt, R.A.; Hyman, H.H.; Vogler, S.

    1962-08-14

    A process of countercurrently extracting an aqueous mineral acid feed solution for the separation of actinides from lanthanides dissolved therern is described. The feed solution is made acid-defrcient with alkali metal hydroxide prior to.contact with acid extractant; during extraction, however, acid is transferred from organic to aqueous solution and the aqueous solution gradually becomes acid. The acid-deficient phase ' of the process promotes the extraction of the actinides, while the latter acid phase'' of the process improves retention of the lanthanides in the aqueous solution. This provides for an improved separation. (AEC)

  20. Solvent Extraction of Alkaline Earth Metals with Alkylphosphorus Acids

    Institute of Scientific and Technical Information of China (English)

    XUXin; ZHUTun

    2002-01-01

    Solvent extraction equiliria of four main alkaline earth metals (magnesium, calcium, strontium and barium) with di(2-ethylhexyl) phosphoric acid (DEHPA), 2-ethylhexyl phosphonic acid mono-(2-ethylhexyl) ester, di(2,4,4-tri-methylpentyl) phosphinic acid and IR spectra of the extracts have been studied. The selectivity order is dependent of the e/r value and hydration energy of the metal ions. The minor shift of the P→O in IR absorption of the alkaline earth metal extracts indicates that the interaction between the metal ions and P→O is much weaker for alkaline earth metals than for transitional metals. The distribution of the four alkaline earth elements between aqueous solutions and solutions of DEHPA and neutral organophosphorus compunds, tri-n-butyl phosphate (TBP) or tri-octyl phosphine oxide (TOPO) in kerosene have been determined at varying ratio of TBP or TOPO to DEHPA and the positive synergism is observed. The synergic effects is explained by using IR spectra of the loaded organic phase.

  1. Synthesis of oxime from a renewable resource for metal extraction

    Energy Technology Data Exchange (ETDEWEB)

    Hoang, Anh Son; Tran, Thi Huong; Nguyen, Hong Nhung; Vu, Hong Son; Vo, Thanh Phong [Institute of Materials Science, Hanoi (Viet Nam); Phan, Chi; Nguyen, Thanh Vinh [Curtin University, Perth (Australia)

    2015-08-15

    A new method for semi-synthesis of alkyl salicylaldoximes from cardanol is reported. Cardanol was extracted from decarboxylation process of cashew nutshell liquid, an abundant agricultural by-product. Molecular structures, physical and chemical properties of cardanol and oxime derivatives were confirmed by spectroscopic analyses. The produced oximes were successfully employed to extract copper(II) cation from aqueous copper salt solutions, offering a practical and economical pathway to effectively recover metals using agricultural by-products.

  2. Ecotoxicology of heavy metals: Liquid-phase extraction by nanosorbents

    Science.gov (United States)

    Burakov, A.; Romantsova, I.; Babkin, A.; Neskoromnaya, E.; Kucherova, A.; Kashevich, Z.

    2015-11-01

    The paper considers the problem of extreme toxicity heavy metal compounds dissolved in wastewater and liquid emissions of industrial enterprises to living organisms and environment as a whole. The possibility of increasing extraction efficiency of heavy metal ions by sorption materials was demonstrated. The porous space of the latter was modified by carbon nanotubes (CNTs) during process of the chemical vapour deposition (CVD) of carbon on metal oxide catalysts. The increasing of the sorption capacity (10-30%) and the sorption rate of nanomodified activated carbons in comparison with standard materials in the example of absorption of Co2+ and Ni2+ ions from aqueous solutions was proven.

  3. Complexation-induced supramolecular assembly drives metal-ion extraction.

    Science.gov (United States)

    Ellis, Ross J; Meridiano, Yannick; Muller, Julie; Berthon, Laurence; Guilbaud, Philippe; Zorz, Nicole; Antonio, Mark R; Demars, Thomas; Zemb, Thomas

    2014-09-26

    Combining experiment with theory reveals the role of self-assembly and complexation in metal-ion transfer through the water-oil interface. The coordinating metal salt Eu(NO3)3 was extracted from water into oil by a lipophilic neutral amphiphile. Molecular dynamics simulations were coupled to experimental spectroscopic and X-ray scattering techniques to investigate how local coordination interactions between the metal ion and ligands in the organic phase combine with long-range interactions to produce spontaneous changes in the solvent microstructure. Extraction of the Eu(3+)-3(NO3(-)) ion pairs involves incorporation of the "hard" metal complex into the core of "soft" aggregates. This seeds the formation of reverse micelles that draw the water and "free" amphiphile into nanoscale hydrophilic domains. The reverse micelles interact through attractive van der Waals interactions and coalesce into rod-shaped polynuclear Eu(III) -containing aggregates with metal centers bridged by nitrate. These preorganized hydrophilic domains, containing high densities of O-donor ligands and anions, provide improved Eu(III) solvation environments that help drive interfacial transfer, as is reflected by the increasing Eu(III) partitioning ratios (oil/aqueous) despite the organic phase approaching saturation. For the first time, this multiscale approach links metal-ion coordination with nanoscale structure to reveal the free-energy balance that drives the phase transfer of neutral metal salts.

  4. COMPARING METAL AND TRANSPARENT MATRICES IN PREVENTING GINGIVAL OVERHANG WITH DIFFERENT RESIN MATERIAL IN CLASS II RESTORATIONS – AN SEM STUDY

    Directory of Open Access Journals (Sweden)

    Dr Dinesh Shetty

    2010-06-01

    Full Text Available Transparent matrices and reflective wedges are difficult to adapt, thus their ability to prevent gingival overhang was compared in this study with metal matrices and wooden wedges.Class II MOD cavitieswere prepared and randomly divided into six groups. Group I microhybrid composite, Group II flowable composite liner and Group III compomer. In above 3 groups metal matrices and wooden wedges were used. Group IV microhybrid composite, Group V flowable composite liner and GroupVI compomer. In above 3 groups transparent matrices and light reflecting wedges were used.Specimens were filled with respective resin composite material, using corresponding matrix andwedge.Percentage of gingival overhang was determined under SEM.The result showed greateroverhang formation in transparent matrix group compared to metal matrix group as transparentmatrices are difficult to adapt to the teeth

  5. Synthesis and Characterization of Nanostructure Transition Metal Oxides Extracted from Industrial Waste (EOFD) by Hydrothermal Method

    Science.gov (United States)

    Girisun, T. C. Sabari; Babeela, C.; Vidhya, V.

    2011-10-01

    Electric oil furnace dust (EOFD) is a solid waste generated in the collection of particulate material during steelmaking process in electric and oil furnaces. Over 7 million metric tons dust produced per annum in worldwide creates deep impacts like soil, ground water and ecology pollutions. This article reports the simple one step process for the extraction of nanostructured metal oxides from the industrial waste (EOFD) for the realization of low cost solar applications. By hydrothermal technique valuable metals were obtained in the form of metal oxides. Initially the presence of metals was identified by ICP analysis. XRD analysis confirms the formation of nano structured titanium oxide (TiO) along with traces of iron oxide (Fe2O3). The surface morphology and the particle size were analyzed by SEM analysis. Thus the metal oxides derived could be helpful to reduce the burden on the environment, increase the development of the source nano material and reduce the cost of raw materials for solar cell applications.

  6. Scanning electron microscopy (SEM) and X-ray dispersive spectrometry evaluation of direct laser metal sintering surface and human bone interface: a case series.

    Science.gov (United States)

    Mangano, Carlo; Piattelli, Adriano; Raspanti, Mario; Mangano, Francesco; Cassoni, Alessandra; Iezzi, Giovanna; Shibli, Jamil Awad

    2011-01-01

    Recent studies have shown that direct laser metal sintering (DLMS) produces structures with complex geometry and consequently that allow better osteoconductive properties. The aim of this patient report was to evaluate the early bone response to DLMS implant surface retrieved from human jaws. Four experimental DLMS implants were inserted in the posterior mandible of four patients during conventional dental implant surgery. After 8 weeks, the micro-implants and the surrounding tissue were removed and prepared for scanning electron microscopy (SEM) and histomorphometric analysis to evaluate the bone-implant interface. The SEM and EDX evaluations showed a newly formed tissue composed of calcium and phosphorus. The bone-to-implant contact presented a mean of 60.5 ± 11.6%. Within the limits of this patient report, data suggest that the DLMS surfaces presented a close contact with the human bone after a healing period of 8 weeks.

  7. An Overview on Metal Cations Extraction by Azocalixarenes

    Directory of Open Access Journals (Sweden)

    Hasalettin Deligöz

    2011-12-01

    Full Text Available In this overview, our main aim is to present the design, preparation, characterization, and extraction/sorption properties of chromogenic azocalix[4]arenes (substituted with different groups toward metal cations. Azocalixarenes, which contain a conjugated chromophore, i.e. azo (-N=N- group are synthesized in “one-pot” procedures in satisfactory yields. A wide variety of applications is expected by the functionalization of the side arms. Some of them are used to complex with metal ions. These macrocycles due to their bowl-shaped geometry are indeed used as hosts allowing ionic or organic guests to coordinate onto their cavity. The azocalixarene based ionophores are generally applied in various fields such as catalyst recovery, power plant, agriculture, metals finishing, microelectonics, biotechnology processes, rare earths speciation, and potable water purification. Besides these, they find applications in the area of selective ion extractions, receptors, optical devices, chemical sensor devices, the stationary phase for capillary chromatography, ion transport membranes, and luminescence probes etc. This survey is focused to provide overview an of the versatile nature of azocalix[n]arenes as highly efficient extractants for metal ions treated as pollutants.

  8. Microfocus study of metal distribution and speciation in tissue extracted from revised metal on metal hip implants

    Energy Technology Data Exchange (ETDEWEB)

    Hart, Alister J [Department of Orthopaedic Surgery, Imperial College and Imperial College Healthcare NHS Trust, Charing Cross Hospital Campus, Fulham Palace Rd, London W6 8RF (United Kingdom); Sandison, Ann [Department of Histopathology, Imperial College and Imperial College Healthcare NHS Trust, Charing Cross Hospital Campus, Fulham Palace Rd, London W6 8RF (United Kingdom); Quinn, Paul; Mosselmans, J Frederick W [Science Division, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxon, OX11 0DE (United Kingdom); Sampson, Barry [Department of Clinical Biochemistry, Imperial College and Imperial College Healthcare NHS Trust, Charing Cross Hospital Campus, Fulham Palace Rd, London W6 8RF (United Kingdom); Atkinson, Kirk D [8 Nuclear Department Defence Academy College of Management and Technology HMS Sultan Military Road Gosport PO12 3BY (United Kingdom); Skinner, John A [Department of Orthopaedics, Royal National Orthopaedic Hospital, HA7 4LP (United Kingdom); Goode, Angela [Dept of Materials, Imperial College London, SW7 2AZ (United Kingdom); Powell, Jonathan J, E-mail: Paul.Quinn@diamond.ac.u [Medical Research Council Human Nutrition Research Centre, Cambridge CB1 9NL (United Kingdom)

    2009-11-15

    Unexplained tissue inflammation in metal-on-metal hip replacements is suspected to be caused by implant-derived nanoparticles. The aim of this study was to investigate the nature of the metal particles in tissue surrounding metal-on-metal (MOM) hips that has been extracted during revision. Mapping of tissue surrounding the failed MOM hips was performed using microfocus X-ray Fluorescence (XRF). This revealed mainly Cr which was localized to the cellular regions. There was co-localisation of Co, were present, to areas of high Cr abundance. XANES of the tissue and appropriate standards revealed that the most common species were Cr(III) and Co(II). EXAFS analysis of the tissue and various metal standards revealed that the most abundant implant-related species was Cr(III) phosphate. Different tissue preparation methods, including frozen sectioning, were examined but were found not to affect the distribution or speciation of the metals in the tissue.

  9. Novel thiosalicylate-based ionic liquids for heavy metal extractions

    Energy Technology Data Exchange (ETDEWEB)

    Leyma, Raphlin; Platzer, Sonja [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna (Austria); Jirsa, Franz [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna (Austria); Department of Zoology, University of Johannesburg, PO Box 524, Auckland Park, 2006, Johannesburg (South Africa); Kandioller, Wolfgang, E-mail: wolfgang.kandioller@univie.ac.at [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna (Austria); Krachler, Regina; Keppler, Bernhard K. [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna (Austria)

    2016-08-15

    Highlights: • Six thiosalicylate-based ammonium and phosphonium ionic liquids (ILs) were newly synthesized. • ILs showed good extraction of cadmium, copper, and zinc. • Phosphonium ILs showed better extraction efficiencies than their ammonium counterparts. - Abstract: This study aims to develop novel ammonium and phosphonium ionic liquids (ILs) with thiosalicylate (TS) derivatives as anions and evaluate their extracting efficiencies towards heavy metals in aqueous solutions. Six ILs were synthesized, characterized, and investigated for their extracting efficacies for cadmium, copper, and zinc. Liquid-liquid extractions of Cu, Zn, or Cd with ILs after 1–24 h using model solutions (pH 7; 0.1 M CaCl{sub 2}) were assessed using flame atomic absorption spectroscopy (F-AAS). Phosphonium-based ILs trihexyltetradecylphosphonium 2-(propylthio)benzoate [P{sub 66614}][PTB] and 2-(benzylthio)benzoate [P{sub 66614}][BTB] showed best extraction efficiency for copper and cadmium, respectively and zinc was extracted to a high degree by [P{sub 66614}][BTB] exclusively.

  10. Ionic liquids for extraction of metals and metal containing compounds from communal and industrial waste water.

    Science.gov (United States)

    Fischer, Lisa; Falta, Thomas; Koellensperger, Gunda; Stojanovic, Anja; Kogelnig, Daniel; Galanski, Markus; Krachler, Regina; Keppler, Bernhard K; Hann, Stephan

    2011-10-01

    In a fundamental study the potential of ionic liquids based on quaternary ammonium- and phosphonium cations and thiol-, thioether-, hydroxyl-, carboxylate- and thiocyanate-functionalized anions has been assessed for future application in advanced sewage treatment. The elimination of the metal(oid)s Ag, As, Cd, Cr, Cu, Hg, Ni, Pb, Pt, Sn, Zn and the cancerostatic platinum compounds cisplatin and carboplatin was screened using a liquid phase micro-extraction set-up. The analytical tool-set consisted of ICP-SFMS and LC-ICP-MS for quantification of metal(oid)s and cancerostatic platinum compounds, respectively. The purity of the ILs was assessed for the investigated metal(oid)s on the base of present EU environmental quality standards and was found to be sufficient for the intended use. In model solutions at environmental relevant concentrations extraction efficiencies≥95% could be obtained for Ag, Cu, Hg and Pt with both phosphonium- and ammonium-based ILs bearing sulphur functionality in the form of thiosalicylate and 2-(methylthiobenzoate) anions, as well as with tricaprylmethylammonium thiocyanate within an extraction time of 120 min. All other metals were extracted to a lower extent (7-79%). In the case of cancerostatic platinum compounds a phosphonium-based IL bearing thiosalicylate functionality showed high extraction efficiency for monoaquacisplatin. For the first time, liquid phase micro extraction with ionic liquids was applied to industrial and communal waste water samples. The concentration of all investigated metal(oid)s could be significantly reduced. The degree of elimination varied with the initial concentration of metals, pH and the amount of suspended particulate matter.

  11. Sequential extraction of heavy metals during composting of urban waste

    Institute of Scientific and Technical Information of China (English)

    Ayari F.; Chairi R.; Kossai R.

    2008-01-01

    In urban waste (the first matter of compost), elements such as copper, nickel and lead may be found in metallic state (wire, pile, accumulator, etc.), which is considered as non-dependent state. The work undertaken at the laboratory of composting of the INRST in Henchir Lihoudia (Tunis) showed that the produced compost does not contain any mobile metallic element and the portion related to organic fraction (bioavailable) is tiny in size. We sup-posed that many reactions involving decomposition and complexation from elements related to the matrix compo-nents occurred during composting. The existence and importance of this phenomenon can be evaluated by studying the evolution of metal contents in the different fractions extracted sequentially during composting process.

  12. In Vitro Antibacterial Mechanism of Action of Crude Garlic (Allium sativum) Clove Extract on Selected Probiotic Bifidobacterium Species as Revealed by SEM, TEM, and SDS-PAGE Analysis.

    Science.gov (United States)

    Booyens, J; Labuschagne, M C; Thantsha, M S

    2014-06-01

    There has been much research on the effects of garlic (Allium sativum) on numerous pathogens, but very few, if any, studies on its effect on beneficial, probiotic bifidobacteria. We have recently shown that garlic exhibits antibacterial activity against bifidobacteria. The mechanism by which garlic kills bifidobacteria is yet to be elucidated. This study sought to determine the mechanism of action of garlic clove extract on selected Bifidobacterium species using scanning and transmission electron microscopy and SDS-PAGE analysis. SEM micrographs revealed unusual morphological changes such as cell elongation, cocci-shaped cells with cross-walls, and distorted cells with bulbous ends. With TEM, observed changes included among others, condensation of cytoplasmic material, disintegration of membranes, and loss of structural integrity. SDS-PAGE analysis did not reveal any differences in whole-cell protein profiles of untreated and garlic clove extract-treated cells. The current study is the first to reveal the mechanism of action of garlic clove extract on probiotic Bifidobacterium species. The results indicate that garlic affects these beneficial bacteria in a manner similar to that exhibited in pathogens. These results therefore further highlight that caution should be taken especially when using raw garlic and probiotic bifidobacteria simultaneously as viability of these bacteria could be reduced by allicin released upon crushing of garlic cloves, thereby limiting the health benefits that the consumer anticipate to gain from probiotics.

  13. Extraction of metals using supercritical fluid and chelate forming legand

    Science.gov (United States)

    Wai, Chien M.; Laintz, Kenneth E.

    1998-01-01

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated .beta.-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated .beta.-diketone and a trialkyl phosphate, or a fluorinated .beta.-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated .beta.-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

  14. Extraction of metals using supercritical fluid and chelate forming ligand

    Science.gov (United States)

    Wai, C.M.; Laintz, K.E.

    1998-03-24

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated {beta}-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated {beta}-diketone and a trialkyl phosphate, or a fluorinated {beta}-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated {beta}-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process. 7 figs.

  15. Statistical evaluation of metal fill widths for emulated metal fill in parasitic extraction methodology

    Science.gov (United States)

    J-Me, Teh; Noh, Norlaili Mohd.; Aziz, Zalina Abdul

    2015-05-01

    In the chip industry today, the key goal of a chip development organization is to develop and market chips within a short time frame to gain foothold on market share. This paper proposes a design flow around the area of parasitic extraction to improve the design cycle time. The proposed design flow utilizes the usage of metal fill emulation as opposed to the current flow which performs metal fill insertion directly. By replacing metal fill structures with an emulation methodology in earlier iterations of the design flow, this is targeted to help reduce runtime in fill insertion stage. Statistical design of experiments methodology utilizing the randomized complete block design was used to select an appropriate emulated metal fill width to improve emulation accuracy. The experiment was conducted on test cases of different sizes, ranging from 1000 gates to 21000 gates. The metal width was varied from 1 x minimum metal width to 6 x minimum metal width. Two-way analysis of variance and Fisher's least significant difference test were used to analyze the interconnect net capacitance values of the different test cases. This paper presents the results of the statistical analysis for the 45 nm process technology. The recommended emulated metal fill width was found to be 4 x the minimum metal width.

  16. Review of Biohydrometallurgical Metals Extraction from Polymetallic Mineral Resources

    Directory of Open Access Journals (Sweden)

    Helen R. Watling

    2014-12-01

    Full Text Available This review has as its underlying premise the need to become proficient in delivering a suite of element or metal products from polymetallic ores to avoid the predicted exhaustion of key metals in demand in technological societies. Many technologies, proven or still to be developed, will assist in meeting the demands of the next generation for trace and rare metals, potentially including the broader application of biohydrometallurgy for the extraction of multiple metals from low-grade and complex ores. Developed biotechnologies that could be applied are briefly reviewed and some of the difficulties to be overcome highlighted. Examples of the bioleaching of polymetallic mineral resources using different combinations of those technologies are described for polymetallic sulfide concentrates, low-grade sulfide and oxidised ores. Three areas for further research are: (i the development of sophisticated continuous vat bioreactors with additional controls; (ii in situ and in stope bioleaching and the need to solve problems associated with microbial activity in that scenario; and (iii the exploitation of sulfur-oxidising microorganisms that, under specific anaerobic leaching conditions, reduce and solubilise refractory iron(III or manganese(IV compounds containing multiple elements. Finally, with the successful applications of stirred tank bioleaching to a polymetallic tailings dump and heap bioleaching to a polymetallic black schist ore, there is no reason why those proven technologies should not be more widely applied.

  17. Pillared metal(IV) phosphate-phosphonate extraction of actinides

    Energy Technology Data Exchange (ETDEWEB)

    Burns, J.D.; Clearfield, A. [Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry; Borkowski, M.; Reed, D.T. [Los Alamos National Laboratory, Carlsbad, NM (United States). Earth and Environmental Sciences Div.

    2012-07-01

    Four pillared metal(IV) phosphate-phosphonate ion exchange materials were synthesized and characterized. Studies were conducted to determine their affinity for the lanthanides (Ln's) and actinides (An's). It was determined that by simply manipulating the metal source (Zr or Sn) and the phosphate source (H{sub 3}PO{sub 4} or Na{sub 3}PO{sub 4}) large differences were seen in the extraction of the Ln and An species. K{sub d} values higher than 4 x 10{sup 5} were observed for the AnO{sub 2}{sup 2+} species in nitric acid at pH 2. These basic uptake experiments are important, as the data they provide may indicate the possibility of a separation of Ln's from An's or even more notably americium from curium and Ln's. (orig.)

  18. Bio-extraction of precious metals from urban solid waste

    Science.gov (United States)

    Das, Subhabrata; Natarajan, Gayathri; Ting, Yen-Peng

    2017-01-01

    Reduced product lifecycle and increasing demand for electronic devices have resulted in the generation of huge volumes of electronic waste (e-waste). E-wastes contain high concentrations of toxic heavy metals, which have detrimental effects on health and the environment. However, e-wastes also contain significant concentrations of precious metals such as gold, silver and palladium, which can be a major driving force for recycling of urban waste. Cyanogenic bacteria such as Chromobacterium violaceum generate cyanide as a secondary metabolite which mobilizes gold into solution via a soluble gold-cyanide complex. However, compared to conventional technology for metal recovery, this approach is not effective, owing largely to the low concentration of lixiviants produced by the bacteria. To overcome the challenges of bioleaching of gold from e-waste, several strategies were adopted to enhance gold recovery rates. These included (i) pretreatment of e-waste to remove competing metal ions, (ii) mutation to adapt the bacteria to high pH environment, (iii) metabolic engineering to produce higher cyanide lixiviant, and (iv) spent medium leaching with adjusted initial pH. Compared to 7.1 % recovery by the wild type bacteria, these strategies achieved gold recoveries of 11.3%, 22.5%, 30% and 30% respectively at 0.5% w/v pulp density respectively. Bioleached gold was finally mineralized and precipitated as gold nanoparticles using the bacterium Delftia acidovorans. This study demonstrates the potential for enhancement of biocyanide production and gold recovery from electronic waste through different strategies, and extraction of solid gold from bioleached leachate.

  19. Technologies for Extracting Valuable Metals and Compounds from Geothermal Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Stephen [SIMBOL Materials

    2014-04-30

    Executive Summary Simbol Materials studied various methods of extracting valuable minerals from geothermal brines in the Imperial Valley of California, focusing on the extraction of lithium, manganese, zinc and potassium. New methods were explored for managing the potential impact of silica fouling on mineral extraction equipment, and for converting silica management by-products into commercial products.` Studies at the laboratory and bench scale focused on manganese, zinc and potassium extraction and the conversion of silica management by-products into valuable commercial products. The processes for extracting lithium and producing lithium carbonate and lithium hydroxide products were developed at the laboratory scale and scaled up to pilot-scale. Several sorbents designed to extract lithium as lithium chloride from geothermal brine were developed at the laboratory scale and subsequently scaled-up for testing in the lithium extraction pilot plant. Lithium The results of the lithium studies generated the confidence for Simbol to scale its process to commercial operation. The key steps of the process were demonstrated during its development at pilot scale: 1. Silica management. 2. Lithium extraction. 3. Purification. 4. Concentration. 5. Conversion into lithium hydroxide and lithium carbonate products. Results show that greater than 95% of the lithium can be extracted from geothermal brine as lithium chloride, and that the chemical yield in converting lithium chloride to lithium hydroxide and lithium carbonate products is greater than 90%. The product purity produced from the process is consistent with battery grade lithium carbonate and lithium hydroxide. Manganese and zinc Processes for the extraction of zinc and manganese from geothermal brine were developed. It was shown that they could be converted into zinc metal and electrolytic manganese dioxide after purification. These processes were evaluated for their economic potential, and at the present time Simbol

  20. Native Australian species are effective in extracting multiple heavy metals from biosolids.

    Science.gov (United States)

    Mok, Hoi-Fei; Majumder, Ramaprasad; Laidlaw, W Scott; Gregory, David; Baker, Alan J M; Arndt, Stefan K

    2013-01-01

    Selecting native plant species with characteristics suitable for extraction of heavy metals may have multiple advantages over non-native plants. Six Australian perennial woody plant species and one willow were grown in a pot trial in heavy metal-contaminated biosolids and a potting mix. The plants were harvested after fourteen months and above-ground parts were analysed for heavy metal concentrations and total metal contents. All native species were capable of growing in biosolids and extracted heavy metals to varying degrees. No single species was able to accumulate heavy metals at particularly high levels and metal extraction depended upon the bioavailability of the metal in the substrate. Metal extraction efficiency was driven by biomass accumulation, with the species extracting the most metals also having the greatest biomass yield. The study demonstrated that Grevillea robusta, Acacia mearnsii, Eucalyptus polybractea, and E. cladocalyx have the greatest potential as phytoextractor species in the remediation of heavy metal-contaminated biosolids. Species survival and growth were the main determinants of metal extraction efficiency and these traits will be important for future screening of native species.

  1. Effect of Apple, Baobab, Red-Chicory, and Pear Extracts on Cellular Energy Expenditure and Morphology of Caco-2 Cells using Transepithelial Electrical Resistance (TEER) and Scanning Electron Microscopy (SEM)

    Science.gov (United States)

    The present study investigated the effects of four food extracts on the Caco-2 intestinal cell line using a new transepithelial electrical resistance method (TEER) concurrent with electron microscopy (SEM). Caco-2 cells are widely used in transepithelial studies because they can be cultured to creat...

  2. Advances in the extractive metallurgy of selected rare and precious metals

    Science.gov (United States)

    Hoffmann, James E.

    1991-04-01

    The broad field of extractive metallurgy, often perceived as an unimportant point of light in the universe of technology, has undergone significant, fundamental changes in the past 30 years. Improved extraction technologies now permit greater metal recovery, reduce the time that metal values are chemically locked up and diminish the economic impact of environmental regulations. Much of this accomplishment is due to the application of solvent extraction. As evidenced by improvements in the extraction of rare and precious metals, research in extractive metallurgy technology not only exists, but has achieved palpable results.

  3. Three dimensional analysis of the pore space in fine-grained Boom Clay, using BIB-SEM (broad-ion beam scanning electron microscopy), combined with FIB (focused ion-beam) serial cross-sectioning, pore network modeling and Wood's metal injection

    Science.gov (United States)

    Hemes, Susanne; Klaver, Jop; Desbois, Guillaume; Urai, Janos

    2014-05-01

    The Boom Clay is, besides the Ypresian clays, one of the potential host rock materials for radioactive waste disposal in Belgium (Gens et al., 2003; Van Marcke & Laenen, 2005; Verhoef et al., 2011). To access parameters, which are relevant for the diffusion controlled transport of radionuclides in the material, such as porosity, pore connectivity and permeability, it is crucial to characterize the pore space at high resolution (nm-scale) and in 3D. Focused-ion-beam (FIB) serial cross-sectioning in combination with high resolution scanning electron microscopy (SEM), pore network modeling, Wood's metal injection and broad-ion-beam (BIB) milling, constitute a superior set of methods to characterize the 3D pore space in fine-grained, clayey materials, down to the nm-scale resolution. In the present study, we identified characteristic 3D pore space morphologies, determined the 3D volume porosity of the material and applied pore network extraction modeling (Dong and Blunt, 2009), to access the connectivity of the pore space and to discriminate between pore bodies and pore throats. Moreover, we used Wood's metal injection (WMI) in combination with BIB-SEM imaging to assess the pore connectivity at a larger scale and even higher resolution. The FIB-SEM results show a highly (~ 90 %) interconnected pore space in Boom Clay, down to the resolution of ~ 3E+03 nm³ (voxel-size), with a total volume porosity of ~ 20 %. Pore morphologies of large (> 5E+08 nm³), highly interconnected pores are complex, with high surface area to volume ratios (shape factors G ~ 0.01), whereas small (BIB-SEM, down to a resolution of ~ 50 nm² pixel-size, indicates an interconnected porosity fraction of ~ 80 %, of a total measured 2D porosity of ~ 20 %. Determining and distinguishing between pore bodies and pore throats enables us to compare 3D FIB-SEM pore-size distributions to 2D BIB-SEM data, as well as MIP data. Results show a good agreement between the 2D BIB-SEM and 3D FIB-SEM inferred pore

  4. Modes of Occurrence of Fluorine by Extraction and SEM Method in a Coal-Fired Power Plant from Inner Mongolia, China

    Directory of Open Access Journals (Sweden)

    Guangmeng Wang

    2015-12-01

    Full Text Available In this study, an extraction method and environmental scanning electron microscopy (SEM are employed to reveal the changes in the occurrence mode of fluorine in a coal-fired power plant in Inner Mongolia, China. The different occurrence states of fluorine during coal combustion and emission show that fluorine in coal mainly assumes insoluble inorganic mineral forms. The results illustrate that the three typical occurrence modes in coal are CaF2, MgF2 and AlF3. The fluorine in fly ash can be captured by an electrostatic precipitator (EPS or a bag filter. In contrast, the gaseous fluorine content in flue gas is only in the range of several parts per million; thus, it cannot be used in this study. The occurrence mode of fluorine in bottom ash and slag is inorganic villiaumite (e.g., soluble NaF, KF and insoluble CaF2 which is difficult to break down even at high temperatures. The occurrence mode of fluorine with the highest content in fly ash is physically adsorbed fluorine along the direction of the flue gas flow. The insoluble inorganic mineral fluoride content in fly ash is also high, but the gradually increasing fluorine content in fly ash is mainly caused by physical adsorption. Fluorine in the coal-fired power plant discharges mostly as solid products; however, very little fluorine emitted into the environment as gas products (HF, SiF4 cannot be captured. The parameters used in this study may provide useful references in developing a monitoring and control system for fluorine in coal-fired power plants.

  5. Review on aggregation of acid extractants in solvent extraction of metal ions: remark on the general model

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The aggregation behavior of various acid extractants in the solvent extraction systems of metal ions is re-examined and explained according to knowledge obtained in recent work. The conclusions are as follows. (1) Complexes formed by the extractants and metal ions can form reversed micelles in organic diluents, depending on the microstructures of the complexes. The dimers of the acid extractant cannot percolate to the metal-extractant aggregates, and the acid-salt complexes are always formed in the aggregates. The reversed micelles or the W/O microemulsions formed by different species cannot be associated with each other to form a unified aggregate. (2) In solvent extraction systems, hydration of the extractants and metal ions can be considered as the driving force of forming reversed micelles. (3) Information of the first approach to the insight of the bicontinuous microemulsion of NaDEHP shows that various components in the aqueous phase behave confined and very similar to the typical AOT/n-heptane W/O microemulsions. (4) In the extraction of lanthanide ions by the W/O microemulsion of sodium naphthenate, the saponification is a process of forming reversed micelle or W/O microemulsion, while the extraction step is a process of destroying reversed micelles or W/O microemulsion droplets.

  6. Pyrophosphate coupling with chelant-enhanced soil flushing of field contaminated soils for heavy metal extraction.

    Science.gov (United States)

    Yan, Dickson Y S; Lo, Irene M C

    2012-01-15

    This study investigated the influence of flushing duration, [S,S]-ethylenediaminedisuccinic acid (EDDS) dosage, humic acid and various combinations of ethylenediaminetetraacetic acid (EDTA), EDDS and tetrasodium pyrophosphate (Na(4)P(2)O(7)) on metal extraction during soil flushing, through column experiments. A lesser extent of enhancement in metal extraction efficiencies was found when the flushing duration and the dosage of EDDS was doubled, compared to their efficiencies measured at pore volume 100. Metal extraction efficiency was mainly influenced by the initial metal distribution in the soils rather than the flushing duration and the EDDS-to-metal molar ratio. Humic acid of less than 10mg/L as dissolved organic carbon (DOC) posed an insignificant effect on metal extraction during EDDS enhanced soil flushing. The extraction rate of Ni by EDTA and EDDS was time dependent, and was initially fast in the case of EDDS, whereas it was slow for EDTA. However, the overall Ni extraction efficiency by EDTA was higher when the flushing time was longer. Na(4)P(2)O(7) promoted the mineral dissolution which enhanced the metal extraction as a result of soil disruption. The order of metal extraction by Na(4)P(2)O(7) was Ni>Cr>Cu, probably be due to the different affinities between metals and P(2)O(7)(4-). Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Accumulation of some metals by legumes and their extractability from acid mine spoils. [USA - Alabama

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, R.W.; Ibeabuchi, I.O.; Sistani, K.R.; Shuford, J.W. (Alabama A M University, Normal, AL (USA). Dept. of Plant and Soil Science)

    A greenhouse study was conducted to investigate the growth (dry matter yield) of selected legume cover crops; phytoaccumulation of metals such as Zn, Mn, Pb, Cu, Ni, and Al; the extractability of heavy metals from three different Alabama acid mine spoils. The spoils were amended based on soil test recommended levels of N, P, K, Ca and Mg prior to plant growth. Metals were extracted by three extractants (Mehlich 1, DTPA, and 0.1 M HCl) and values correlated with their accumulation by the selected legumes. Among the cover crops, kobe lespedeza {ital Lespedeza striata} (Thung.) Hook and Arn, sericea lespedeza {ital Lespedeza cuneata} (Dum.) G. Don, and red clover (Trifolium pratense L.) did not survive the stressful conditions of the spoils. However, cowpea (Vigna unguiculata L.) followed by Bragg' soybean {ital Glycine max} (L.) Merr. generally produced the highest dry matter yield while accumulating the largest quantity of metals, except Al, from spoils. The extractability of most metals from the spoils was generally in the order of: 0.1 MHCl {gt} DTPA. Mehlich 1 did not extract Pb and 0.1 M HCl did not extract Ni, whereas DTPA extracted all the metals in a small amount relative to HCl and Mehlich 1. All the extractants were quite effective in removing plant-available Zn from the spoils. In general, the extractants' ability to predict plant-available metals depended on the crop species, spoil type, and extractant used. 28 refs., 4 tabs.

  8. Release of microspherolites and metals extraction from energetical fly ashes by Bacillus isolates

    Directory of Open Access Journals (Sweden)

    Štyriaková Iveta

    2000-09-01

    Full Text Available The amorphous secondary silicate mineral components formed in the process of coal combustion dominate in the composition of energy fly-ash. Depending on the composition of coal concentrate, this secondary raw material source also contains the industrially interesting components, e.g. titanium (eventually iron and aluminium and can be considered as a non-metallic material suitable for the construction industry.The main secondary mineral components of the energy fly-ash formed during the coal combustion were studied using SEM (scanning electronic microscope. They can be divided into four groups:1. Amorphous spherical alumocilicate particles in allotriomorphic aluminosilicate grains – they represent a main mineral component of fly-ash, which is formed from the accompanying rocks of coal containing silicate minerals,2. Quartz – which formed a substantial component of accompanying rocks of coal or accompanying accessory mineral of coal together with kaolinite and mica, was transformed into tridymite at the temperature exceeding 870°C and into cristobalite at the temperature exceeding 1470°C. The spherical particles are products of reaction between cristobalite and aluminosilicate, which is a frequent phenomenon occurring during the formation of volcanic rocks. These particles form together a main amorphous phase of fly-ash.3. Mullite – represents a secondary component of fly-ash, which is formed from accompanying clay minerals of coal (kaolinite, mica together with cristobalite under the effect of temperature exceeding 1150°C,4. Non-combusted residue – consists of organic substance, represents a non-combusted ratio of coal as a secondary component of fly-ash.Heterotrophic bacteria of Bacillus genus are capable to remove 66 % of titanium and 33 % of iron from non-deposited fly-ash from Opatovice after 35 days of leaching of samples. The content of solid phase in fly-ash influences the extraction of elements, mainly iron and titatnium, because

  9. Recovery of heavy metals from industrial sludge using various acid extraction approaches.

    Science.gov (United States)

    Wu, C H; Kuo, C Y; Lo, S L

    2009-01-01

    Heavy metals were removed from industrial sludge by traditional and microwave-assisted acid extraction approaches. The effects of acid concentration, extraction time, sludge particle size and solid/liquid (S/L) ratio on copper-extraction efficiency were assessed. Leaching with increased acid concentrations increased the yield of heavy metals from the industrial sludge. In microwave-assisted acid extraction, reducing the S/L ratio and sludge particle size increased copper-extraction efficiency. These experimental findings indicate that S/L ratio most strongly influenced microwave-assisted acid extraction. Both traditional and microwave-assisted acid extraction demonstrate that sulfuric acid was an effective extractant, and the copper fraction in extracted sludge shifted from being primarily bound to Fe-Mn oxides and organic-matter partition, to being mostly bound to organic matter, remaining as a residue during acid extraction.

  10. Extracting porosity and modelling permeability from μCT and FIB-SEM data of fractured dolomites from a hydrocarbon reservoir

    Science.gov (United States)

    Voorn, M. H.; Rath, A.; Exner, U.

    2012-04-01

    Currently oil and gas in the Vienna Basin are produced partly from the Upper Triassic Hauptdolomit formation. Various drill-cores were retrieved from densely fractured dolomites from depths between 3000 and 5300 m. Porosity and permeability assessment in specimen from such fractured rocks proves to be difficult by common laboratory methods, and also 2D sample analysis alone is insufficient to this end. In our study, X-ray micro-Computed Tomography (µCT) is used to visualise the inside of core samples of fractured Hauptdolomit. The biggest advantage of µCT is that it provides a 3D view of the fractures and other porosity, without destroying the sample. Core sample descriptions, 2D thin section analysis and standard laboratory measurements are used for extended analysis and cross-calibration of the results. In addition, 3D porosity visualisations at the micro- to nano-scale are obtained from Focussed Ion Beam - Scanning Electron Microscopy (FIB-SEM) on thin sections. The narrow fractures encountered in the Hauptdolomit samples require sufficient resolution µCT scans (i.e. better than ca. 25 µm). Full 10 cm diameter cores of sample prove to be too thick and dense, so that the fracture network cannot be recorded properly. 3 cm sized plugs on the other hand do provide workable results. After obtaining good datasets, the fractures need to be segmented (separated) from the full dataset for further analysis. A large amount of different segmentation routines is available from literature, but very little are applicable for segmenting narrow fractures, especially not in geological literature. Our current best results stem from applying the so-called "Frangi filter" used in segmentation routines in the medical sciences for segmenting blood vessels. After this segmentation, the fracture patterns can be extracted, and quantitative analysis of the bulk porosity and porosity distribution, fracture aperture and length can be performed. The data obtained by FIB-SEM is treated in

  11. Extraction and Binding Efficiency of Calix[8]arene Derivative Toward Selected Transition Metals

    Directory of Open Access Journals (Sweden)

    Imdadullah Qureshi

    2008-12-01

    Full Text Available In this article we have explored the extraction efficiency as well as binding ability of calix[8]arene derivative (3 for selected transition metal ions (Co2+, Cd2+, Ni2+, Pb2+ and Cu2+. Picrate salt solutions of these metals were used in the liquid-liquid extraction experiments. It is apparent from the results that ligand 3 shows appreciable high extraction of transition metal cations, with the relative order Pb2+>Cu2+>Ni2+>Co2+>Cd2+ being observed. Highest extraction efficiency has been observed for Pb2+ and Cu2+ i.e. 95 and 91% respectively. The significant extraction and complexation ability for these metal ions may be attributed to the nature, size, structure and geometry of both ligand and metal ions.

  12. Liquid-liquid extraction of metal ions by the 6-membered N-containing macrocycle hexacyclen.

    Science.gov (United States)

    Arpadjan, S; Mitewa, M; Bontchev, P R

    1987-11-01

    The nitrogen-containing analogue of 18-crown-6, 1,4,7,10,13,16-hexa-azaoctadecane (hexacyclen)] was studied as a reagent for complexation and extraction of some metal ions. It was found that with this reagent and methyl isobutyl ketone, metal ions such as silver(I), mercury(II), copper(II), platinum(II) and palladium(II) can be quantitatively extracted and separated from iron(III) and some other metal ions.

  13. Modified sequential extraction for biochar and petroleum coke: Metal release potential and its environmental implications.

    Science.gov (United States)

    von Gunten, Konstantin; Alam, Md Samrat; Hubmann, Magdalena; Ok, Yong Sik; Konhauser, Kurt O; Alessi, Daniel S

    2017-07-01

    A modified Community Bureau of Reference (CBR) sequential extraction method was tested to assess the composition of untreated pyrogenic carbon (biochar) and oil sands petroleum coke. Wood biochar samples were found to contain lower concentrations of metals, but had higher fractions of easily mobilized alkaline earth and transition metals. Sewage sludge biochar was determined to be less recalcitrant and had higher total metal concentrations, with most of the metals found in the more resilient extraction fractions (oxidizable, residual). Petroleum coke was the most stable material, with a similar metal distribution pattern as the sewage sludge biochar. The applied sequential extraction method represents a suitable technique to recover metals from these materials, and is a valuable tool in understanding the metal retaining and leaching capability of various biochar types and carbonaceous petroleum coke samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. The correlation of metal content in medicinal plants and their water extracts

    Directory of Open Access Journals (Sweden)

    Ranđelović Saša S.

    2013-01-01

    Full Text Available The quality of some medicinal plants and their water extracts from South East Serbia is determined on the basis of metal content using atomic absorption spectrometry. The two methods were used for the preparation of water extracts, to examine the impact of the preparation on the content of metals in them. Content of investigated metals in both water extracts is markedly lower then in medicinal plants, but were higher in water extract prepared by method (I, with exception of lead content. The coefficients of extraction for the observed metal can be represented in the following order: Zn > Mn > Pb > Cu > Fe. Correlation coefficients between the metal concentration in the extract and total metal content in plant material vary in the range from 0.6369 to 0.9956. This indicates need the plants to be collected and grown in the unpolluted area and to examine the metal content. The content of heavy metals in the investigated medicinal plants and their water extracts is below the maximum allowable values, so they are safe to use.

  15. Comparison of partial extraction reagents for assessing potential bioavailability of heavy metals in sediments.

    Science.gov (United States)

    Brady, James P; Kinaev, Irina; Goonetilleke, Ashantha; Ayoko, Godwin A

    2016-05-15

    Assessment of heavy metal bioavailability in sediments is complex because of the number of partial extraction methods available for the assessment and the general lack of certified reference materials. This study evaluates five different extraction methodologies to ascertain the relative strengths and weaknesses of each method. The results are then compared to previously published work to ascertain the most effective partial extraction technique, which was established to dilute (0.75-1M) nitric acid solutions. These results imply that single reagent; weak acid extractions provide a better assessment of potentially bioavailable metals than the chelating agents used in sequential extraction methods.

  16. Rapid metal extractability tests from polluted mining soils by ultrasound probe sonication and microwave-assisted extraction systems.

    Science.gov (United States)

    García-Salgado, Sara; Quijano, M Ángeles

    2016-12-01

    Ultrasonic probe sonication (UPS) and microwave-assisted extraction (MAE) were used for rapid single extraction of Cd, Cr, Cu, Ni, Pb, and Zn from soils polluted by former mining activities (Mónica Mine, Bustarviejo, NW Madrid, Spain), using 0.01 mol L(-1) calcium chloride (CaCl2), 0.43 mol L(-1) acetic acid (CH3COOH), and 0.05 mol L(-1) ethylenediaminetetraacetic acid (EDTA) at pH 7 as extracting agents. The optimum extraction conditions by UPS consisted of an extraction time of 2 min for both CaCl2 and EDTA extractions and 15 min for CH3COOH extraction, at 30% ultrasound (US) amplitude, whereas in the case of MAE, they consisted of 5 min at 50 °C for both CaCl2 and EDTA extractions and 15 min at 120 °C for CH3COOH extraction. Extractable concentrations were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The proposed methods were compared with a reduced version of the corresponding single extraction procedures proposed by the Standards, Measurements and Testing Programme (SM&T). The results obtained showed a great variability on extraction percentages, depending on the metal, the total concentration level and the soil sample, reaching high values in some areas. However, the correlation analysis showed that total concentration is the most relevant factor for element extractability in these soil samples. From the results obtained, the application of the accelerated extraction procedures, such as MAE and UPS, could be considered a useful approach to evaluate rapidly the extractability of the metals studied.

  17. Fate of metals before and after chemical extraction of incinerated sewage sludge ash.

    Science.gov (United States)

    Li, Jiang-Shan; Tsang, Daniel C W; Wang, Qi-Ming; Fang, Le; Xue, Qiang; Poon, Chi Sun

    2017-08-05

    Chemical extraction of incinerated sewage sludge ash (ISSA) can effectively recycle P, but it may change the speciation and mobility of the remaining metals. This study investigated the changes of the leaching potential and distribution of metals in the chemically extracted ISSA. Batch extraction experiments with different extractants, including inorganic acids, organic acids, and chelating agents, were conducted on the ISSA collected from a local sewage sludge incinerator. The extraction of Zn, Cu, Pb, Ni, Cd, Ba, Cr and As from the ISSA and the corresponding changes of the mobility and speciation were examined. The results showed that the metals in ISSA were naturally stable because large portions of metals were associated with the residual fraction. The inorganic (HNO3 and H2SO4) and organic acids (citric acid and oxalic acid) significantly co-dissolved the metals through acid dissolution, but the reduction in the total concentrations did not tally the leaching potential of the residual metals. The increase in the exchangeable fraction due to destabilization by the extractants significantly enhanced the mobility and leachability of the metals in the residual ISSA. Chelating agents (EDTA and EDTMP) only extracted a small quantity of metals and had a marginal effect on the fate of the residual metals, but they significantly reduced the Fe/Mn oxide-bound fraction. In comparison, the bioaccessibility of residual metals were reduced to varying extent. Therefore, the disposal or reuse of chemically extracted ISSA should be carefully evaluated in view of possible increase in mobility of residual metals in the environment. Copyright © 2017. Published by Elsevier Ltd.

  18. EXTRACTION, RECOVERY, AND BIOSTABILITY OF EDTA FOR REMEDIATION OF HEAVY METAL-CONTAMINATED SOIL. (R825549C052)

    Science.gov (United States)

    Chelation removal of heavy metals from contaminated soil is seen as a viable remediation technique. A useful chelating agent should be strong, reusable, and biostable during metal extraction and recovery operations. This work tested the extraction, recovery, and biostability o...

  19. EXTRACTION, RECOVERY, AND BIOSTABILITY OF EDTA FOR REMEDIATION OF HEAVY METAL-CONTAMINATED SOIL. (R825549C052)

    Science.gov (United States)

    Chelation removal of heavy metals from contaminated soil is seen as a viable remediation technique. A useful chelating agent should be strong, reusable, and biostable during metal extraction and recovery operations. This work tested the extraction, recovery, and biostability o...

  20. Emerging technologies in extraction and processing of metals

    Science.gov (United States)

    Reddy, Ramana G.

    2003-04-01

    The growing need to conserve energy and materials and prevent environmental pollution led to an increased demand for better understanding of potential as well as existing processes. In this context, thermodynamic and transport modeling of materials and processes provides a rapid and cost-effective means of conducting and minimizing the complexity of experimental investigations and developing innovative and environmentally friendly metallurgical processes. This presentation concentrates on some fundamentals on new technologies as extractive metallurgy of copper, lead, aluminum, and other nonferrous metals and processing of nanocomposites. The newer routes of copper smelting and modeling of impurities in copper and lead slags and mattes are reviewed. The copper smelting capacity increased by a factor of 10 during the last three decades, the smelting rate increased by a factor of 6, and the process fuel equivalent decreased by a factor of 2. The a priori prediction, with no adjustable parameters, of impurity capacities of S and As in copper slags and S in lead slags, based on the Reddy-Blander model, is reviewed. Excellent agreement between the model-predicted capacities data and laboratory experimental and industrial data was observed. The model is an invaluable tool for optimization of process parameters in the efficient removal of impurities from the nonferrous-metals smelting and refining processes. A new in-situ processing technology for the production of a lightweight alloy matrix with ceramic particle reinforcements such as SiC in aluminum alloy matrix composites by bubbling reactive gas is reviewed. Thermal plasma processing of a nanoscale aluminum alloy matrix with TiC and TiN composites is discussed. The in-situ formed reinforcements are thermodynamically stable, and the composite particles are of uniform size. The optimum process parameters for the production of composite powders by thermal plasma are discussed. A low-temperature aluminum production and

  1. Surplus Cost Potential as a Life Cycle Impact Indicator for Metal Extraction

    Directory of Open Access Journals (Sweden)

    Marisa D.M. Vieira

    2016-01-01

    Full Text Available In the evaluation of product life cycles, methods to assess the increase in scarcity of resources are still under development. Indicators that can express the importance of an increase in scarcity of metals extracted include surplus ore produced, surplus energy required, and surplus costs in the mining and the milling stage. Particularly the quantification of surplus costs per unit of metal extracted as an indicator is still in an early stage of development. Here, we developed a method that quantifies the surplus cost potential of mining and milling activities per unit of metal extracted, fully accounting for mine-specific differences in costs. The surplus cost potential indicator is calculated as the average cost increase resulting from all future metal extractions, as quantified via cumulative cost-tonnage relationships. We tested the calculation procedure with 12 metals and platinum-group metals as a separate group. We found that the surplus costs range six orders of magnitude between the metals included, i.e., between $0.01–$0.02 (iron and $13,533–$17,098 (rhodium USD (year 2013 per kilogram of metal extracted. The choice of the reserve estimate (reserves vs. ultimate recoverable resource influenced the surplus costs only to a limited extent, i.e., between a factor of 0.7 and 3.2 for the metals included. Our results provide a good basis to regularly include surplus cost estimates as resource scarcity indicator in life cycle assessment.

  2. Metal extraction from Cetraria islandica (L. Ach. lichen using low pH solutions

    Directory of Open Access Journals (Sweden)

    ANA A. CUCULOVIC

    2008-04-01

    Full Text Available Extraction of metals (K, Al, Ca, Mg, Fe, Cu, Ba, Zn, Mn and Sr from dry Cetraria islandica (L. Ach. lichen was performed using solutions similar to acid rain (solution A – H2SO4–HNO3–(NH42SO4 and solution B – H2SO4–HNO3–(NH42SO4–NH4NO3. The pH values of these solutions were 2.00, 2.58, 2.87, 3.28, and 3.75. Five consecutive extractions were performed with each solution. In all solutions, the extracted metal content, except Cu and Ca, was the highest in the first extract. The highest percentage of the metals desorbed in the first extraction was obtained using solutions with low pH values, 2.00, 2.58, and 2.87. The lowest percentage in the first extraction was obtained using solutions with pH 3.28 and 3.75, indicating influence of the H+ ion on the extraction. According to the results obtained, the investigated metals form two groups. The first group includes K, Al, Ca, Mg, and Fe. They were extracted in each of the five extractions at each of the pH values. The second group includes Ba, Zn, Mn, Cu, and Sr, which were not all extracted at each pH value. The first group yielded three types of extraction curves when the logarithms of extracted metal amounts were plotted as a function of the number of successive extractions. These effects indicate that three different positions (centres of metal ion accumulation exist in the lichen (due to sorption, complex formation, or other processes present in the tissues.

  3. A comparison between heavy metals released from soil and its efficient speciation extracted by sequential extraction procedure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui

    2008-01-01

    A simulating experiment was carried out on the interaction between natural precipitation and soil. The results demonstrated that the contents of heavy metals (V, Co, Cr, and Ni) released from soil into the solution under Earth's surface conditions are higher than the contents of those metals bonded to exchangeable species, which were extracted by sequential extraction procedure recommended by Tessier and others in 1979. It is demonstrated that the metals bonded to other 3 species (carbonate, Fe-Mn oxide, and organic matter) except those bonded to the exchangeable species in efficient speciation can be released under the Earth's surface conditions, when pH=4 in the reaction system, and the higher correlation coefficient indicated that the concentrations of heavy metals released from soil into the solution vary approximately with reaction time in terms of index regulations.

  4. Review on calixarene-type macrocycles and metal extraction data

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, R. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1995-12-01

    This paper gives an overview on the current state of solvent extraction studies with derivatized [1.n]-metacyclophanes and related compounds. 122 References from the last ten years are discussed and data on extractability, extraction equilibria, and complex formation are presented in graphical form. (author) 122 refs.

  5. Ao leitor sem medo

    Directory of Open Access Journals (Sweden)

    José Eisenberg

    2000-05-01

    Full Text Available O texto resenha Ao leitor sem medo, de Renato Janine Ribeiro (Belo Horizonte, UFMG, 1999.This text is a review of Ao leitor sem medo by Renato Janine Ribeiro (Belo Horizonte, UFMG, 1999

  6. [Removal of heavy metals from extract of Angelica sinensis by EDTA-modified chitosan magnetic adsorbent].

    Science.gov (United States)

    Ren, Yong; Sun, Ming-Hui; Peng, Hong; Huang, Kai-Xun

    2013-11-01

    The concentrations of heavy metals in the extracting solutions of traditional Chinese medicine are usually very low. Furthermore, a vast number of organic components contained in the extracting solutions would be able to coordinate with heavy metals, which might lead to great difficulty in high efficient removal of them from the extracting solutions. This paper was focused on the removal of heavy metals of low concentrations from the extracting solution of Angelica sinensis by applying an EDTA-modified chitosan magnetic adsorbent (EDTA-modified chitosan/SiO2/Fe3O4, abbreviated as EDCMS). The results showed that EDCMS exhibited high efficiency for the removal of heavy metals, such as Cu, Cd and Pb, e.g. the removal percentage of Cd and Pb reached 90% and 94.7%, respectively. Besides, some amounts of other heavy metals like Zn and Mn were also removed by EDCMS. In addition, the total solid contents, the amount of ferulic acid and the HPLC fingerprints of the extracting solution were not changed significantly during the heavy metal removal process. These results indicate that EDCMS may act as an applicable and efficient candidate for the removal of heavy metals from the extracting solution of A. sinensis.

  7. Acute Toxicity of the Crocus Alatavicus Regel et Sem Sativus Corms Extract on Mice%白番红花球茎提取物对小鼠急性毒性的实验研究

    Institute of Scientific and Technical Information of China (English)

    杨元华; 刘静; 韩汝春; 陈媛媛; 孙艳; 周冬梅; 牛榕

    2015-01-01

    Objective To observe acute toxicity of the Crocus alatavicus Regel et Sem sativus corms extract in mice,evaluate its safety,provide a theoretical basis for new drug research and clinical safety of medication.Methods To record its activity and toxicity in mice by Acute toxicity test method,The mouse ig with different concentrations (88.80、93.86、99.20、104.86、1 1 1.00g/kg) of Crocus alatavicus Regel et Sem sativus corms extract;Using Karber method modified to calculate Crocus alatavicus Regel et Sem corms extract on mice ig median lethal dose (LD50 ) and 95% confidence intervals.Results Crocus alatavicus Regel et Sem sativus corms extract on mice 7d ig LD50 is 100.46g/kg,Its 95%confidence interval 91.42~109.50g/kg.ConclusionCrocus alatavicus Re-gel et Sem sativus corms extract had lower toxicity,It provide a scientific basis for pharmacodynamic experimental and clinical applica-tions.%目的:观察白番红花球茎提取物对小鼠的急性毒性反应,评价其安全性,为其新药开发和临床安全用药提供理论依据。方法:采用急性毒性实验方法,对小鼠ig不同浓度(88.80、93.86、99.20、104.86、111.00g/kg)的白番红花球茎提取物,观察并记录小鼠的活动和毒性反应;采用改良寇氏法计算白番红花球茎提取物对小鼠ig的半数致死量(LD50)和95%的可信区间。结果:白番红花球茎提取物对小鼠7d内ig的LD50为100.46g/kg,其95%的可信区间为91.42~109.50g/kg。结论:白番红花球茎提取物有较小的毒性,该结果为其药效学实验和临床应用提供了科学依据。

  8. Technical note: removal of metal ion inhibition encountered during DNA extraction and amplification of copper-preserved archaeological bone using size exclusion chromatography.

    Science.gov (United States)

    Matheson, Carney D; Marion, Travis E; Hayter, Shana; Esau, Neal; Fratpietro, Renee; Vernon, Kim K

    2009-10-01

    A novel technique for the removal of metal ions inhibiting DNA extraction and PCR of archaeological bone extracts is presented using size exclusion chromatography. Two case studies, involving copper inhibition, demonstrate the effective removal of metal ion inhibition. Light microscopy, SEM, elemental analysis, and genetic analysis were used to demonstrate the effective removal of metal ions from samples that previously exhibited molecular inhibition. This research identifies that copper can cause inhibition of DNA polymerase during DNA amplification. The use of size exclusion chromatography as an additional purification step before DNA amplification from degraded bone samples successfully removes metal ions and other inhibitors, for the analysis of archaeological bone. The biochemistry of inhibition is explored through chemical and enzymatic extraction methodology on archaeological material. We demonstrate a simple purification technique that provides a high yield of purified DNA (>95%) that can be used to address most types of inhibition commonly associated with the analysis of degraded archaeological and forensic samples. We present a new opportunity for the molecular analysis of archaeological samples preserved in the presence of metal ions, such as copper, which have previously yielded no DNA results.

  9. Relative extraction ratio (RER) for arsenic and heavy metals in soils and tailings from various metal mines, Korea.

    Science.gov (United States)

    Son, Hye Ok; Jung, Myung Chae

    2011-01-01

    This study focused on the evaluation of leaching behaviours for arsenic and heavy metals (Cd, Cu, Ni, Pb and Zn) in soils and tailings contaminated by mining activities. Ten representative mine soils were taken at four representative metal mines in Korea. To evaluate the leaching characteristics of the samples, eight extraction methods were adapted namely 0.1 M HCl, 0.5 M HCl, 1.0 M HCl, 3.0 M HCl, Korean Standard Leaching Procedure for waste materials (KSLP), Synthetic Precipitation Leaching Procedure (SPLP), Toxicity Characteristic Leaching Procedure (TCLP) and aqua regia extraction (AR) methods. In order to compare element concentrations as extraction methods, relative extraction ratios (RERs, %), defined as element concentration extracted by the individual leaching method divided by that extracted by aqua regia based on USEPA method 3050B, were calculated. Although the RER values can vary upon sample types and elements, they increase with increasing ionic strength of each extracting solution. Thus, the RER for arsenic and heavy metals in the samples increased in the order of KSLP extraction method, the RER values for Cd and Zn were relatively higher than those for As, Cu, Ni and Pb. This may be due to differences in geochemical behaviour of each element, namely high solubility of Cd and Zn and low solubility of As, Cu, Ni and Pb in surface environment. Thus, the extraction results can give important information on the degree and extent of arsenic and heavy metal dispersion in the surface environment.

  10. Comparison between sequential and single extraction procedures for metal speciation in fresh and dried Sedum Plumbizincicola

    Institute of Scientific and Technical Information of China (English)

    宋祖威; 仲兆平; 钟道旭; 吴龙华; 骆永明

    2015-01-01

    Sequential and single extraction procedures were applied to both fresh and driedSedum Plumbizincicola leaves and stems. The extractants, different from those of soil, sediment or sewage sludge metal fractions, were water, 80% (v/v) ethanol, 1 mol/L NaCl, 2% HAc and 0.6 mol/L HCl. Zn, Cd and Cu in the extracts and samples were measured by flame atomic adsorption spectrometry. In sequential extraction procedures, water soluble form and ethanol soluble form are the main fractions for Zn, while water soluble form and NaCl soluble form for Cd, and comparatively uniform distribution for Cu with the residue form most and HCl soluble form second. Single extraction procedures are used to compare the extraction efficiencies of the five reagents to screen appropriate extractants and operating conditions for liquid extraction to deal with large amount of harvested metal-contained biomass, which will pose a threat to the environment if treated improperly. The sequences of extraction efficiencies are HCl>NaCl≈HAc>Water≈Ethanol for Zn and HCl≈NaCl≈HAc>Water>Ethanol for Cd. As for Cu, all the five extractants cannot effectively extract Cu, but HCl achieves a higher efficiency (>70% in fresh samples, and 45%−60% in dried samples). Besides, extraction efficiencies for most extractants in fresh samples are higher than those in dried samples, and extraction efficiencies of stems and leaves for the five extractants are close. The two extraction procedures can obtain high degree of accuracy with the relative standard deviation (RSD) lower than 10%, and metal recoveries are controlled between 80%−120% with most of 90%−110%.

  11. On Depth Information Extraction from Metal Detector Signals

    NARCIS (Netherlands)

    Schoolderman, A.J.; Wolf, F.J. de; Merlat, L.

    2003-01-01

    Information on the depth of objects detected with the help of a metal detector is useful for safe excavation of these objects in demining operations. Apart from that, depth informatíon may be used in advanced sensor fusion algorithms for a detection system where a metal detector is combíned with eg.

  12. Extractive decontamination of heavy metals from CCA contaminated ...

    African Journals Online (AJOL)

    user

    contaminated soil obtained from a wood treatment factory site by four organic acids are ... that 59% As, 19% Cr and 5% Cu were potentially bio-available and mobile. ... potential industrial source of heavy metals is the wood ... by the European Union, it remains the main chemical ..... metals in soils irrigated with wastewater.

  13. Heavy metal concentration in forage grasses and extractability from some acid mine spoils

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, R.W.; Ibeabuchi, I.O.; Sistani, K.R.; Shuford, J.W. (Alabama A and M University, Normal (United States). Department of Plant and Soil Science)

    1993-06-01

    Laboratory and greenhouse studies were conducted on several forage grasses, bermudagrass ([ital Cynodon dactylon]), creeping red fescue ([ital Festuca rubra]), Kentucky 31-tall fescue ([ital Festuca arundinacea]), oat ([ital Avena sativa]), orchardgrass ([ital Dactylis glomerata]), perennial ryegrass ([ital Lolium perenne]), sorghum ([ital Sorghum bicolor]), triticale (X. [ital triticosecale Wittmack]), and winter wheat ([ital Triticum aestivum]) grown on three Alabama acid mine spoils to study heavy metal accumulation, dry matter yield and spoil metal extractability by three chemical extractants (Mehlich 1, DTPA, and 0.1 M HCl). Heavy metals removed by these extractants were correlated with their accumulation by several forage grasses. Among the forages tested, creeping red fescue did not survive the stressful conditions of any of the spoils, while orchard grass and Kentucky 31-tall fescue did not grow in Mulberry spoil. Sorghum followed by bermudagrass generally produced the highest dry matter yield. However, the high yielding bermudagrass was most effective in accumulating high tissue levels of Mn and Zn from all spoils (compared to the other grasses) but did not remove Ni. On the average, higher levels of metals were extracted from spoils in the order of 0.1 M HCl[gt] Mehlich 1[gt] DTPA. However, DTPA extracted all the metals from spoils while Mehlich 1 did not extract Pb and 0.1 M HCl did not extract detectable levels of Ni. All of the extractants were quite effective in determining plant available Zn from the spoils. For the other metals, the effective determination of plant availability depended on the crop, the extractant, and the metal in concert. 20 refs., 6 tabs.

  14. Separation of heavy metals from landfill leachate by reactive liquid-liquid extraction

    Energy Technology Data Exchange (ETDEWEB)

    Mickler, W. [Potsdam Univ. (Germany). Inst. fuer Anorganische Chemie und Didaktik der Chemie

    2001-05-01

    The objective of this work was to investigate the decontamination of a model landfill leachate by simultaneous separation of heavy metals from alkaline earth metals and iron in order to obtain a leachate that can be led back to the landfill. Reactive extraction as a separation process offers the possibility of selectively separating cations, that is, of separating toxic components from less problematic ones, and also includes the possibility of electrolysis and further processes to obtain the desired metals. (orig.)

  15. Liquid-phase extraction coupled with metal-organic frameworks-based dispersive solid phase extraction of herbicides in peanuts.

    Science.gov (United States)

    Li, Na; Wang, Zhibing; Zhang, Liyuan; Nian, Li; Lei, Lei; Yang, Xiao; Zhang, Hanqi; Yu, Aimin

    2014-10-01

    Liquid-phase extraction coupled with metal-organic frameworks-based dispersive solid phase extraction was developed and applied to the extraction of pesticides in high fatty matrices. The herbicides were ultrasonically extracted from peanut using ethyl acetate as extraction solvent. The separation of the analytes from a large amount of co-extractive fat was achieved by dispersive solid-phase extraction using MIL-101(Cr) as sorbent. In this step, the analytes were adsorbed on MIL-101(Cr) and the fat remained in bulk. The herbicides were separated and determined by high-performance liquid chromatography. The experimental parameters, including type and volume of extraction solvent, ultrasonication time, volume of hexane and eluting solvent, amount of MIL-101(Cr) and dispersive solid phase extraction time, were optimized. The limits of detection for herbicides range from 0.98 to 1.9 μg/kg. The recoveries of the herbicides are in the range of 89.5-102.7% and relative standard deviations are equal or lower than 7.0%. The proposed method is simple, effective and suitable for treatment of the samples containing high content of fat.

  16. Quantitative Ultrasound-Assisted Extraction for Trace-Metal Determination: An Experiment for Analytical Chemistry

    Science.gov (United States)

    Lavilla, Isela; Costas, Marta; Pena-Pereira, Francisco; Gil, Sandra; Bendicho, Carlos

    2011-01-01

    Ultrasound-assisted extraction (UAE) is introduced to upper-level analytical chemistry students as a simple strategy focused on sample preparation for trace-metal determination in biological tissues. Nickel extraction in seafood samples and quantification by electrothermal atomic absorption spectrometry (ETAAS) are carried out by a team of four…

  17. Removal of heavy metal contamination from peanut skin extracts by waste biomass adsorption

    Science.gov (United States)

    Polyphenols are a rapidly increasing portion of the nutraceutical and functional food marketplace. Peanut skins are a waste product which have potential as a low-cost source of polyphenols. Extraction and concentration of peanut skin extracts can cause normally innocuous levels of the heavy metal co...

  18. Comparison of three sequential extraction procedures to describe metal fractionation in anaerobic granular sludges

    NARCIS (Netherlands)

    Hullebusch, van E.D.; Sudarno, S.; Zandvoort, M.H.; Lens, P.N.L.

    2005-01-01

    In the last few decades. several sequential extraction procedures have been developed to quantify the chemical status of metals in the solid phase. In this study. three extraction techniques (modified [A. Tessier, P.G.C. Campbell, M. Bisson, Anal. Chem. 51 (1979) 844]: [R.C. Stover. L.E. Sommers, D.

  19. Quantitative Ultrasound-Assisted Extraction for Trace-Metal Determination: An Experiment for Analytical Chemistry

    Science.gov (United States)

    Lavilla, Isela; Costas, Marta; Pena-Pereira, Francisco; Gil, Sandra; Bendicho, Carlos

    2011-01-01

    Ultrasound-assisted extraction (UAE) is introduced to upper-level analytical chemistry students as a simple strategy focused on sample preparation for trace-metal determination in biological tissues. Nickel extraction in seafood samples and quantification by electrothermal atomic absorption spectrometry (ETAAS) are carried out by a team of four…

  20. Comparison of three sequential extraction procedures to describe metal fractionation in anaerobic granular sludges

    NARCIS (Netherlands)

    Hullebusch, van E.D.; Sudarno, S.; Zandvoort, M.H.; Lens, P.N.L.

    2005-01-01

    In the last few decades. several sequential extraction procedures have been developed to quantify the chemical status of metals in the solid phase. In this study. three extraction techniques (modified [A. Tessier, P.G.C. Campbell, M. Bisson, Anal. Chem. 51 (1979) 844]: [R.C. Stover. L.E. Sommers, D.

  1. Metal Ions Extraction with Glucose Derivatives as Chelating Reagents in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    Guo Chen YANG; Hai Jian YANG

    2006-01-01

    A series of glucose derivatives have been used as chelating reagents to extract metal ions in supercritical carbon dioxide. With perfluoro-1-octanesulfonic acid tetraethylammonium salt as additive, glucose derivatives were selective for Sr2+ and Pb2+ extraction in supercritical carbon dioxide.

  2. Separation and recovery of heavy metals from waste water using synergistic solvent extraction

    Science.gov (United States)

    Li, Yan; Yang, Limei; Xu, Zheng; Sun, Qi

    2017-01-01

    Heavy metal wastewater pollution is one of the three major water pollutions in the world. The zinc hydrometallurgy smelting process usually discharge large quantities of heavy metal wastewater into the environment. In this paper, a synergistic solvent extraction process has been developed to recover copper, nickel, zinc and cadmium respectively from calcium and magnesium. The synergistic organic system contained 0.50 M Versatic 10 and 0.5 M Mextral 984H in DT100. Adjusting pH to 2.0 at 40 °C, the copper will be extracted preferentially with the extraction rate more than 99%. Continuing to adjust pH to 4.2 at 40 °C, the nickel will be extracted secondly with an extraction rate more than 98%; the zinc and cadmium in raffinate could be extracted separately while pH is about 6.5.

  3. POLY(AMINOMETHYLENEPHOSPHONIC ACID FOR SOLVENT EXTRACTION OF METAL IONS

    Directory of Open Access Journals (Sweden)

    M’hamed Kaid

    2011-09-01

    Full Text Available Diaminododecyltetramethylenetetraphosphonic acid (DADTMTPA has been investigated in liquid - liquid extraction of Zn (II and Cu (II in acetate media. The extraction of both cations was carried out in different media with the addition of CH3COONa, CH3COOH, HCl and H2SO4 at different pH values. The maximum extraction yield for copper is 70% after addition of 10 mg of sodium acetate and for zinc is 30% after addition of acetic acid at pHi = 5.5, in one step.

  4. Metal extraction from the artificially contaminated soil using supercritical CO2 with mixed ligands.

    Science.gov (United States)

    Park, Kwangheon; Lee, Jeongken; Sung, Jinhyun

    2013-04-01

    Supercritical fluids have good penetrating power with a high capacity to dissolve certain solutes in the fluid itself, making it applicable for soil cleaning. Supercritical CO2 along with mixed ligands has been used for cleaning artificially contaminated soil. The extraction of metal from the soil was successful, and the molar ratio of ligands to the extracted metal was as low as 3. Complicated structures with a large surface area of the real soil seemed to cause the lower efficiency. Reduced efficiency was also observed over time after the sample preparation, indicating the possibility of chemisorption of the metal ion onto the soil. The use of supercritical CO2 with dissolved mixed ligands was sufficient to extract metal from the soil. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Comparison of Different Extraction Approaches for Heavy Metal Partitioning in Sediment Samples

    Institute of Scientific and Technical Information of China (English)

    M.B.ARAIN1,; T.G.KAZI; M.K.JAMALI; J.A.BAIG; H.I.AFRIDI; N.JALBANI; R.A.SARFRAZ

    2009-01-01

    Three extraction methods,ultrasonic assisted extraction (USE),microwave assisted extraction (MSE),and conven tional single extraction (CSE),in conjunction with the modified three-stage BCR sequential extraction procedure (SEP)were applied to examine the contents of Cd,Cu,Cr,Ni,Pb and Zn from lake sediment samples,to know whether these techniques can reduce extraction time and improve reproducibility.The SEP and developed alternative single extraction methods were validated by the analysis of certified reference material BCR 601.By the use of optimized sonication and microwave conditions,steps 1,2 and 3 of the BCR sequential extraction methods (excluding the hydrogen peroxide digestion in step 3,which was not performed with sonication and microwave) could be completed in 15-30 min and 60150 s,respectively.The recoveries of total extractable metal contents in BCR 601,obtained by three single extractions ranged from 93.3%-102%,88.9%-104% and 81.2%-96.2% for CSE,USE and MSE,respectively.The precision of the single extraction methods was found in the range of 3.7%-9.4% for all metals (n=6).

  6. Phytotoxicity of trace metals in spiked and field-contaminated soils: Linking soil-extractable metals with toxicity.

    Science.gov (United States)

    Hamels, Fanny; Malevé, Jasmina; Sonnet, Philippe; Kleja, Dan Berggren; Smolders, Erik

    2014-11-01

    Soil tests have been widely developed to predict trace metal uptake by plants. The prediction of metal toxicity, however, has rarely been tested. The present study was set up to compare 8 established soil tests for diagnosing phytotoxicity in contaminated soils. Nine soils contaminated with Zn or Cu by metal mining, smelting, or processing were collected. Uncontaminated reference soils with similar soil properties were sampled, and series of increasing contamination were created by mixing each with the corresponding soil. In addition, each reference soil was spiked with either ZnCl2 or CuCl2 at several concentrations. Total metal toxicity to barley seedling growth in the field-contaminated soils was up to 30 times lower than that in corresponding spiked soils. Total metal (aqua regia-soluble) toxicity thresholds of 50% effective concentrations (EC50) varied by factors up to 260 (Zn) or 6 (Cu) among soils. For Zn, variations in EC50 thresholds decreased as aqua regia > 0.43 M HNO3  > 0.05 M ethylenediamine tetraacetic acid (EDTA) > 1 M NH4 NO3  > cobaltihexamine > diffusive gradients in thin films (DGT) > 0.001 M CaCl2 , suggesting that the last extraction is the most robust phytotoxicity index for Zn. The EDTA extraction was the most robust for Cu-contaminated soils. The isotopically exchangeable fraction of the total soil metal in the field-contaminated soils markedly explained the lower toxicity compared with spiked soils. The isotope exchange method can be used to translate soil metal limits derived from soils spiked with metal salts to site-specific soil metal limits.

  7. Comparisons of metal leachability for various wastes by extraction and leaching methods.

    Science.gov (United States)

    Chang, E E; Chiang, P C; Lu, P H; Ko, Y W

    2001-10-01

    The objective of this research was to evaluate three extraction tests, i.e., toxicity characteristic leaching procedures (TCLP), extraction procedure (EP), and American Society for Testing and Materials (ASTM) methods, for their ability to extract metals in chemical sludge and incineration bottom ash, in terms of the precision of analytical results. Typical chemical sludges, including the electroplating and dye-stuff sludges, the municipal solid waste incineration bottom ash, the leather debris, and the steel-mill bottom residue containing Cd, Cr, Cu, Pb, and Zn were prepared for the lysimetry test (dynamic testing) to compare with the extraction results. Results show that for bottom residue and dye-stuff sludge, the concentration of metal leached was almost the same between the lysimetry leaching and the TCLP tests. The metal concentration followed the order: TCLP approximately = EP > ASTM. TCLP and EP exhibited almost the same relative standard deviation (RSD) value. Therefore, the results of the TCLP tests for bottom residue and dye-stuff sludge, which have a low metal content and alkalinity, can be used to estimate the metal concentration leached by typical acid rain in Taiwan; whereas the ASTM extraction test may be a better indicator of the lysimetry test.

  8. Changes in the extractability of heavy metals on the interaction of sewage sludge with soil

    Energy Technology Data Exchange (ETDEWEB)

    Wollan, E.; Beckett, P.H.T.

    1979-11-01

    To understand better the effects of heavy metals on crops grown on agricultural land, the extractabilities of zinc, copper, and nickel from soil amended with various amounts of sewage sludge were studied. The preparation of sludge-soil mixtures is described, and four experimental trials that measured the amounts of extractable zinc, copper, and nickel at different time intervals are reported. Chemical interactions between sludge and soil are considered. The amounts of copper, nickel, and zinc that could be extracted from the soils were shown to vary according to the time of extraction and in proportion to the sludge/soil ratio. (44 graphs, 25 references, 3 tables)

  9. Transition metal cations extraction by ester and ketone derivatives of chromogenic azocalix[4]arenes.

    Science.gov (United States)

    Ak, Metin; Taban, Deniz; Deligöz, Hasalettin

    2008-06-15

    The molecule of azocalix[n]arene is a macrocyclic used effectively in the complexation of the heavy metal pollutants (like silver and mercury). In this work, our main aim is to prepare new chromogenic azocalix[n]arene molecules to elaborate an extractant with high extractant selectivity for metal ions able to detect this type of pollutant. The solvent extraction properties of four acetyls, four methyl ketones and four benzoyls derivatives from azocalix[4]arenes which were prepared by linking 4-ethyl, 4-n-butyl, 4-acetamid anilin and 2-aminothiazol to calix[4]arene through a diazo-coupling reaction, the alkaline earth (Sr2+) and the transition (Ag+, Hg2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Cr3+) metal cations have been determined by extraction studies with metal picrates. Both ketones are better extractants than esters, and show a strong preference for Ag+, while Cu2+ and Cr3+ are the most extracted cation with the esters. Both acetyl and benzoyl esters are good carriers for Ag+ and Hg2+.

  10. Evaluation of Diazatetraoxa Cryptand as Extractant for Transition Metals and Pb2+

    Directory of Open Access Journals (Sweden)

    Gülsev Dilber

    2014-12-01

    Full Text Available The extractability of metal cations such as Mn2+, Co2+, Cu2+, Zn2+ and Pb2+ from aqueous phase to organic phase with 19-nitro-6,7,15,16,23,24-hexahydro-13H,26H-14,25-propanotribenzo-[b,I,o][1,4,11,14,7,18]-tetraoxadiazacycloikocine was investigated by means of UV-vis spectrophotometer. The aqueous phase and the organic phase contained metal picrate and the ligands, respectively. Chloroform and dichloromethane were the organic solvents. The effect of pH on the percent extraction was evaluated between 2.0 and 5.5 for both organic solvents. The range at which high percent extraction of the ligand was obtained was between pH 5.0 to 5.5 for both solvents. The most effective transport was observed for Mn2+ with 84.69 % picrate among the tested metal picrates with dichloromethane at pH 5.5. The extraction constant values (log Kex were determined for extracted metal complexes at the most effective extraction pH.

  11. Thioglycolate-based task-specific ionic liquids: Metal extraction abilities vs acute algal toxicity.

    Science.gov (United States)

    Platzer, Sonja; Leyma, Raphlin; Wolske, Sara; Kandioller, Wolfgang; Heid, Esther; Schröder, Christian; Schagerl, Michael; Krachler, Regina; Jirsa, Franz; Keppler, Bernhard K

    2017-10-15

    We studied the extraction behavior of two thioglycolate-based ionic liquids (ILs), for heavy metals from aqueous solutions; substances of interest were methyltrioctylammonium S-hexyl thioglycolate [N1888][C6SAc] and methyltrioctylphosphonium S-hexyl thioglycolate [P1888][C6SAc]. Theses ILs previously have shown very good extraction abilities towards cadmium and copper, therefore we investigated time-dependent metal removal experiments with aqueous solutions of cobalt(II), nickel(II) and zinc(II). The highest distribution ratio (RIL/Water) was determined for zinc (RIL/Water=2000). Recovery studies for zinc after extraction were performed with different stripping agents showing a successful recycling. Additionally, the two ILs were immobilized on active charcoal, displaying great potential for solid-liquid extraction. Regarding the extraction mechanism, quantum-mechanical calculations were included, which indicate that the metal extraction depends on the stability of the metal-water cluster. Ligands (water as well as ILs) are planar coordinated in nickel complexes but showed a tetrahedral configuration for zinc. As a first estimate of the ecotoxicity of the ILs, in vivo tests toward three freshwater green algae species Tetradesmus obliquus, Desmodesmus armatus and Raphidocelis subcapitata were carried out. The EC50 values (effective concentration after 72 h) confirm high toxicity of all tested ILs to all species, displaying only small differences between the species and EC50ies. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  12. Lunar Oxygen Production and Metals Extraction Using Ionic Liquids

    Science.gov (United States)

    Marone, Matthew; Paley, Mark Steven; Donovan, David N.; Karr, Laurel J.

    2009-01-01

    Initial results indicate that ionic liquids are promising media for the extraction of oxygen from lunar regolith. IL acid systems can solubilize regolith and produce water with high efficiency. IL electrolytes are effective for water electrolysis, and the spent IL acid media are capable of regeneration.

  13. Chelant extraction of heavy metals from contaminated soils using new selective EDTA derivatives.

    Science.gov (United States)

    Zhang, Tao; Liu, Jun-Min; Huang, Xiong-Fei; Xia, Bing; Su, Cheng-Yong; Luo, Guo-Fan; Xu, Yao-Wei; Wu, Ying-Xin; Mao, Zong-Wan; Qiu, Rong-Liang

    2013-11-15

    Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid (EDTA) and its salts can substantially increase heavy metal removal from contaminated soils and have been extensively studied for soil washing. However, EDTA has a poor utilization ratio due to its low selectivity resulting from the competition between soil major cations and trace metal ions for chelation. The present study evaluated the potential for soil washing using EDTA and three of its derivatives: CDTA (trans-1,2-cyclohexanediaminetetraacetic acid), BDTA (benzyldiaminetetraacetic acid), and PDTA (phenyldiaminetetraacetic acid), which contain a cylcohexane ring, a benzyl group, and a phenyl group, respectively. Titration results showed that PDTA had the highest stability constants for Cu(2+) and Ni(2+) and the highest overall selectivity for trace metals over major cations. Equilibrium batch experiments were conducted to evaluate the efficacy of the EDTA derivatives at extracting Cu(2+), Zn(2+), Ni(2+), Pb(2+), Ca(2+), and Fe(3+) from a contaminated soil. At pH 7.0, PDTA extracted 1.5 times more Cu(2+) than did EDTA, but only 75% as much Ca(2+). Although CDTA was a strong chelator of heavy metal ions, its overall selectivity was lower and comparable to that of EDTA. BDTA was the least effective extractant because its stability constants with heavy metals were low. PDTA is potentially a practical washing agent for soils contaminated with trace metals.

  14. [Extraction of Heavy Metals from Sludge Using Biodegradable Chelating Agent N,N-bis(carboxymethyl) Glutamic Acid Tetrasodium].

    Science.gov (United States)

    Wu, Qing; Cui, Yan-rui; Tang, Xiao-xiao; Yang, Hui-juan; Sun, Jian-hui

    2015-05-01

    N, N-bis (carboxymethyl) glutamic acid tetrasodium (GLDA), a novel biodegradable and green chelating agent, has excellent metal chelating ability. Batch experiment was conducted to study the extraction process of Cd, Ni, Cu and Zn in industrial sludge using GLDA. The effects of contact time, pH of the system, content of chelating agent were investigated, and the forms of heavy metals in sludge pre- and post-extraction using the modified BCR sequential extraction procedure were studied. The results showed that GLDA was effective for cadmium extraction in sludge. Several heavy metals could be effectively extracted under the condition of pH 4 and molar ratio of chelating agent to total heavy metal 3:1. Residual fraction took the largest fraction in Zn, which caused the low extraction efficiency of this metal. Chelating properties were related not only to contact time, pH, chelating agent's concentration, and stability constant but also to species distribution of metals.

  15. Influence of EDDS on metal speciation in soil extracts: measurement and mechanistic multicomponent modeling.

    Science.gov (United States)

    Koopmans, Gerwin F; Schenkeveld, Walter D C; Song, Jing; Luo, Yongming; Japenga, Jan; Temminghoff, Erwin J M

    2008-02-15

    The use of the [S,S]-isomer of EDDS to enhance phytoextraction has been proposed for the remediation of heavy metal contaminated soils. Speciation of metals in soil solution in the presence of EDDS and dissolved organic matter (DOM) received, however, almost no attention, whereas metal speciation plays an important role in relation to uptake of metals by plants. We investigated the influence of EDDS on speciation of dissolved metals in batch extraction experiments using fourfield-contaminated soils with pH varying between 4.7 and 7.2. Free metal concentrations were determined with the Donnan membrane technique, and compared with results obtained with the chemical speciation program ECOSAT and the NICA-Donnan model using a multicomponent approach. Addition of EDDS increased total metal concentrations in our soil extracts by a factor between 1.1 and 32 (Al), 2.1-48 (Cu), 1.1-109 (Fe), 1.1-5.5 (Ni), and 1.3-17 (Zn). In general, Al, Cu, Fe, and Zn had the largest total concentrations in the EDDS-treated extracts, but the contribution of these metals to the sum of total metal concentrations varied significantly between our soils. Free metal concentrations varied between 7.0 and 8.9 (pCd2+), 3.9-9.9 (pCu2+), 6.3-10.2 (pNi2+), and 5.2-7.0 (pZn2+). Addition of EDDS decreased free metal concentrations by a factor between 1.4 and 1.9 (Cd), 3.4-216 (Cu), 1.3-186 (Ni), and 1.3-3.3 (Zn). Model predictions of free metal concentrations were very good, and predicted values were mostly within 1 order of magnitude difference from the measured concentrations. A multicomponent approach had to be used in our model calculations, because competition between Fe and other metals for binding with EDDS was important. This was done by including the solubility of metal oxides in our model calculations. Multicomponent models can be used in chelant-assisted phytoextraction experiments to predict the speciation of dissolved metals and to increase the understanding of metal uptake by plants.

  16. [Extraction of heavy metals from sewage sludge using aspartic acid and citric acid].

    Science.gov (United States)

    Zhang, Hua; Zhu, Zhi-Liang; Zhang, Li-Hua; Qiu, Yan-Ling; Zhao, Jian-Fu

    2008-03-01

    Aspartic acid, as a biodegradable natural amino acid, was used to separate and remove the heavy metals from the sewage sludge based on chemical extraction technology. Under various conditions, the extraction processes were carried out for the sewage sludge from Shanghai Taopu Municipal Wastewater Plant. The comparison of extraction between aspartic acid and citric acid was also discussed for the separation of three heavy metals from sewage sludge. The results showed that pH and the dosage of aspartic acid or citric acid had a significant effect on the extraction efficiency. Zn, Ni and Cu can be apart extracted for more than 85% by aspartic acid at low pH. With the increment of pH value, the extraction ration decreased gradually for both two systems. Within the whole pH range, aspartic acid showed higher extraction efficiency for Ni, Cu than citric acid and the extraction efficiencies of aspartic acid for Ni, Cu were found to respectively be more than 50%, 40%. For the situation of Zn, citric acid had a higher extraction efficiency at pH > or = 3.0.

  17. A rapid fractionation method for heavy metals in soil by continuous-flow sequential extraction assisted by focused microwaves.

    Science.gov (United States)

    Nakazato, Tetsuya; Akasaka, Mikio; Tao, Hiroaki

    2006-11-01

    A microwave-assisted continuous-flow sequential extraction system was developed for rapid fractionation analysis of heavy metals in soil. Insertion of pressure-adjusted air between the extractants provided stable flows of the extractants without mutual mixing and back-pressure influence of a column packed with soil, thereby facilitating reliable continuous-flow extractions. In addition, use of pure water as a pumping solvent removed metal contamination because of direct contact between corrosive extractants and the pump containing metallic materials. Focused microwave irradiation to the soil accelerated the selective extractions of the acid-soluble and reducible fractions of heavy metals in soil in the first and second steps of the sequential extraction conditions, as defined by the Commission of the European Bureau of Reference (BCR). The microwave-assisted continuous-flow extraction provided high correlations in amounts of six heavy metals except Zn in the first step and Cu in the second step extracted from a reference sludge soil, BCR CRM 483, with a conventional batchwise extraction proposed by BCR; continuous-flow extraction assisted by conductive heating provided lower correlations for all the six metals. The proposed method drastically reduced the time required for the sequence extraction to ca. 65 min without losing accuracy and precision of the fractionation analysis of heavy metals in soil, whereas the BCR batchwise method requires ca. 33 h.

  18. Elemental composition study of heavy metal (Ni, Cu, Zn) in riverbank soil by electrokinetic-assisted phytoremediation using XRF and SEM/EDX

    Energy Technology Data Exchange (ETDEWEB)

    Jamari, Suhailly [Faculty of Science, Technology and Human Development, Universiti Tun Hussein Onn Malaysia (UTHM) (Malaysia); Embong, Zaidi [Faculty of Science, Technology and Human Development, Universiti Tun Hussein Onn Malaysia (UTHM) and Research Center for Soft Soils (RECESS), Office of Research, Innovation, Commercialization and Consultancy Management - ORRIC, Universiti Tun Hussein (Malaysia); Bakar, Ismail [Research Center for Soft Soils (RECESS), Office of Research, Innovation, Commercialization and Consultancy Management (ORRIC), Universiti Tun Hussein Onn Malaysia -UTHM, 86400 Batu Pahat, Johor (Malaysia)

    2014-02-12

    Electrokinetic (EK)-assisted phytoremediation is one of the methods that have a big potential in enhancing the ability of plant uptake in soils remediation process. This research was conducted to investigate the difference in elemental composition concentration of riverbank soil and the change of pH between pre- and post-phytoremediation under the following condition: 1) control or as-receive sample; 2) Dieffenbachia spp plant with EK system (a pair of EK electrodes connected to a direct current (DC) power supply). After the electrodes were connected to a magnitude of 6V/cm{sup −1} electric field for 4 hours/day, the soil and plant samples were analyzed using and X-ray Fluorescence Spectrometer (XRF) and Scanning Electron Microscope / Energy Dispersive X-ray Spectroscopy (SEM/EDX). The SEM/EDX analysis showed that concentration of elemental composition (Ni, Cu and Zn) in post-phytoremediation plant powder samples had increase while elemental concentrations in the post-phytoremediation soil samples were decreased. XRF analysis presented a variation in soil elemental composition concentration from anode to cathode where the concentration near anode region increased while decreased near the cathode region. A significant changes in soil pH were obtained where the soil pH increase in cathode region while decrease in anode region. The results reveal that the assistance of EK in phytoremediation process has increase the efficiency of plant uptake.

  19. Elemental composition study of heavy metal (Ni, Cu, Zn) in riverbank soil by electrokinetic-assisted phytoremediation using XRF and SEM/EDX

    Science.gov (United States)

    Jamari, Suhailly; Embong, Zaidi; Bakar, Ismail

    2014-02-01

    Electrokinetic (EK)-assisted phytoremediation is one of the methods that have a big potential in enhancing the ability of plant uptake in soils remediation process. This research was conducted to investigate the difference in elemental composition concentration of riverbank soil and the change of pH between pre- and post-phytoremediation under the following condition: 1) control or as-receive sample; 2) Dieffenbachia spp plant with EK system (a pair of EK electrodes connected to a direct current (DC) power supply). After the electrodes were connected to a magnitude of 6V/cm-1 electric field for 4 hours/day, the soil and plant samples were analyzed using and X-ray Fluorescence Spectrometer (XRF) and Scanning Electron Microscope / Energy Dispersive X-ray Spectroscopy (SEM/EDX). The SEM/EDX analysis showed that concentration of elemental composition (Ni, Cu and Zn) in post-phytoremediation plant powder samples had increase while elemental concentrations in the post-phytoremediation soil samples were decreased. XRF analysis presented a variation in soil elemental composition concentration from anode to cathode where the concentration near anode region increased while decreased near the cathode region. A significant changes in soil pH were obtained where the soil pH increase in cathode region while decrease in anode region. The results reveal that the assistance of EK in phytoremediation process has increase the efficiency of plant uptake.

  20. Biomining-biotechnologies for extracting and recovering metals from ores and waste materials.

    Science.gov (United States)

    Johnson, D Barrie

    2014-12-01

    The abilities of acidophilic chemolithotrophic bacteria and archaea to accelerate the oxidative dissolution of sulfide minerals have been harnessed in the development and application of a biotechnology for extracting metals from sulfidic ores and concentrates. Biomining is currently used primarily to leach copper sulfides and as an oxidative pretreatment for refractory gold ores, though it is also used to recover other base metals, such as cobalt, nickel and zinc. Recent developments have included using acidophiles to process electronic wastes, to extract metals from oxidized ores, and to selectively recover metals from process waters and waste streams. This review describes the microorganisms and mechanisms involved in commercial biomining operations, how the technology has developed over the past 50 years, and discusses the challenges and opportunities for mineral biotechnologies in the 21st century.

  1. Metal nanoparticles (other than gold or silver) prepared using plant extracts for medical applications

    Science.gov (United States)

    Pasca, Roxana-Diana; Santa, Szabolcs; Racz, Levente Zsolt; Racz, Csaba Pal

    2016-12-01

    There are many modalities to prepare metal nanoparticles, but the reducing of the metal ions with plant extracts is one of the most promising because it is considerate less toxic for the environment, suitable for the use of those nanoparticles in vivo and not very expensive. Various metal ions have been already studied such as: cobalt, copper, iron, platinum, palladium, zinc, indium, manganese and mercury and the number of plant extracts used is continuously increasing. The prepared systems were characterized afterwards with a great number of methods of investigation: both spectroscopic (especially UV-Vis spectroscopy) and microscopic (in principal, electron microscopy-TEM) methods. The applications of the metal nanoparticles obtained are diverse and not completely known, but the medical applications of such nanoparticles occupy a central place, due to their nontoxic components, but some diverse industrial applications do not have to be forgotten.

  2. Chemical mutagenesis--a promising technique to increase metal concentration and extraction in sunflowers.

    Science.gov (United States)

    Nehnevajova, Erika; Herzig, Rolf; Federer, Guido; Erismann, Karl-Hans; Schwitzguébel, Jean-Paul

    2007-01-01

    Since most of the metal-hyperaccumulating wild plants only produce very low biomass and many high-yielding crops accumulate only moderate amounts of metals, the current research is mainly focused on overcoming these limitations and the optimization of metal phytoextraction. The main goal of the present study was the improvement of metal concentration and extraction properties of Helianthus annuus L by chemical mutagenesis (the non-GMO approach). Sunflowers--hybrid cultivar Salut and inbred lines-were treated with the chemical mutagen ethyl methanesulfonate (EMS). The effect of chemical mutagenesis on metal concentration in and extraction by new sunflower M1 and M2 mutants was directly assessed on a metal-contaminated field in Raft, Switzerland. Mutants of the M2 generation showed a 2-3 times higher metal shoot concentration than the control plants. The best M2 sunflower "giant mutant" 14/185/04 showed a significantly enhanced metal extraction ability: 7.5 times for Cd, 9.2 times for Zn, and 8.2 times for Pb in aboveground parts, as compared to the control plants. Theoretical calculations for the phytoextraction potential of new sunflower variants note that the best sunflower mutant can produce up to 26 t dry matter per hectare and remove 13.3 kg Zn per hectare and year at the sewage sludge contaminated site of Raft; that is a gain factor of 9 compared to Zn extraction by sunflower controls. Furthermore, the use of sunflower oil and biomass for technical purposes (lubricants, biodiesel, biogas) should produce an additional value and improve the economical balance of phytoextraction.

  3. New technology of extracting the amount of rare earth metals from the red mud

    Science.gov (United States)

    Martoyan, G. A.; Karamyan, G. G.; Vardan, G. A.

    2016-01-01

    The paper outlined the environmental and economic problems associated with red mud - the waste generated in processing of bauxite ore for aluminum production. The chemical analysis of red mud has identified a number of useful elements including rare earth metals. The electromembrane technology of red mud processing with extraction of valuable elements is described. A possible scheme of separation of these metals through electrolysis is also given.

  4. NOVEL IN-SITU METAL AND MINERAL EXTRACTION TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Glenn O' Gorman; Hans von Michaelis; Gregory J. Olson

    2004-09-22

    This white paper summarizes the state of art of in-situ leaching of metals and minerals, and describes a new technology concept employing improved fragmentation of ores underground in order to prepare the ore for more efficient in-situ leaching, combined with technology to continuously improve solution flow patterns through the ore during the leaching process. The process parameters and economic benefits of combining the new concept with chemical and biological leaching are described. A summary is provided of the next steps required to demonstrate the technology with the goal of enabling more widespread use of in-situ leaching.

  5. Separation and preconcentration by a cloud point extraction procedure for determination of metals: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda, C.B.; Rojas, F.S. [University of Malaga, Department of Analytical Chemistry, Faculty of Sciences, Malaga (Spain)

    2009-06-15

    Recently, cloud point extraction (CPE) has been an attractive subject as an alternative to liquid-liquid extraction. The technique is based on the property of most non-ionic surfactants in aqueous solutions to form micelles and become turbid when heated to the cloud point temperature. This review covers a selection of the literature published on applications of CPE in determination of metal ions over the period between 2004 and 2008. (orig.)

  6. SEM and EBSD characterization of bi-layered functionally graded hard metal composites; REM- und EBSD-Charakterisierung von zweischichtigen, funktionell abgestuften Metallverbundwerkstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Prat, Orlando; Sanhueza, Felipe [Univ. de Concepcion (Chile). Dept. de Ingenieria de Materiales; Suarez, Sebastian [Saarland Univ., Saarbruecken (Germany). Chair of Functional Materials; Garcia, Jose [AB Sandvik Coromant R and D, Stockholm (Sweden)

    2016-11-15

    WC-Co bi-layer functionally graded composites were produced by powder metallurgy techniques. The influence of WC particle size and the grain growth inhibitor on the formation of the functionally graded composite was investigated. SEM images show that all sintered samples present a graded microstructure after sintering, with two side regions of extra-coarse and coarse WC-Co and a clear, dense interface without defects or other phases. EBSD results showed a change of WC particle size depending on the processing and the addition of Mo{sub 2}C. Cobalt binder distribution corresponds to WC particle size. Hardness values correlate to WC particle size and binder content. It is shown that tailored hardness/toughness can be produced by adjusting the WC particle size and binder content on both sides of the bi-layer composite.

  7. XRD, DRS, and SEM stundies of the effects of metal dopants (Pt and Au) on the structural and optical properties of TiO2

    CSIR Research Space (South Africa)

    Moloantoa, JR

    2011-07-01

    Full Text Available Au and Pt doped TiO2 nanocrystlas were prepared using the sol gel method. Diffuse Reflectance Spectroscopy (DRS) was used to study the characteristics of these precious metals and X-ray diffraction (XRD) with calculated lattice parameters was used...

  8. Liquid membrane extraction techniques for trace metal analysis and speciation in environmental and biological matrices

    Energy Technology Data Exchange (ETDEWEB)

    Ndungu, Kuria

    1999-04-01

    In this thesis, liquid-membrane-based methods for the analysis of trace metal species in samples of environmental and biological origin were developed. By incorporating extracting reagents in the membrane liquid, trace metal ions were selectively separated from humic-rich natural waters and urine samples, prior to their determination using various instrumental techniques. The extractions were performed in closed flow systems thus allowing easy automation of both the sample clean-up and enrichment. An acidic organophosphorus reagent (DEHPA) and a basic tetraalkylammonium reagent (Aliquat-336) were used as extractants in the membrane liquid to selectively extract and enrich cationic and anionic metal species respectively. A speciation method for chromium species was developed that allowed the determination of cationic Cr(III) species and anionic CR(VI) species in natural water samples without the need of a chromatographic separation step prior to their detection. SLM was also coupled on-line to potentiometric stripping analysis providing a fast and sensitive method for analysis of Pb in urine samples. A microporous membrane liquid-liquid extraction (MMLLE) method was developed for the determination of organotin compounds in natural waters that reduced the number of manual steps involved in the LLE of organotin compounds prior to their CC separation. Clean extracts obtained after running unfiltered humic-rich river water samples through the MMLLE flow system allowed selective determination of all the organotin compounds in a single run using GC-MS in the selected ion monitoring mode (SIM) 171 refs, 9 figs, 4 tabs

  9. Metal alloys, matrix inclusions and manufacturing techniques of Moinhos de Golas collection (North Portugal): a study by micro-EDXRF, SEM-EDS, optical microscopy and X-ray radiography

    Science.gov (United States)

    Loureiro, Joana; Figueiredo, Elin; Silva, Rui J. C.; Araújo, M. Fátima; Fonte, João; Bettencourt, Ana M. S.

    2016-09-01

    A collection of 35 metallic artefacts comprising various typologies, some of which can be attributed to the Bronze Age and others to later periods, were studied to provide detailed information on elemental composition, manufacturing techniques and preservation state. Elemental analysis by micro-EDXRF and SEM-EDS was performed to investigate the use of different alloys and to study the presence of microstructural heterogeneities, as inclusions. X-ray radiography, optical microscopy and SEM-EDS were used to investigate manufacturing techniques and degradation features. Results showed that most of the artefacts were produced in a binary bronze alloy (Cu-Sn) with 10-15 wt% Sn and a low concentration of impurities. Other artefacts were produced in copper or in brass, the latest with varying contents of Zn, Sn and Pb. A variety of inclusions in the metal matrices were also found, some related to specific types of alloys, as (Cu-Ni)S2 in coppers, or ZnS in brasses. Microstructural observations revealed that the majority of the artefacts were subjected to cycles of thermomechanical processing after casting, being evident that among some artefacts different parts were subjected to distinct treatments. The radiographic images revealed structural heterogeneities related to local corrosion processes and fissures that seem to have developed in wear-tension zones, as in the handle of some daggers. Radiographic images were also useful to detect the use of different materials in one particular brass artefact, revealing the presence of a possible Cu-Sn solder.

  10. Enhanced-electrokinetic extraction of heavy metals from dredged harbor sediment.

    Science.gov (United States)

    Yoo, Jong-Chan; Yang, Jung-Seok; Jeon, Eun-Ki; Baek, Kitae

    2015-07-01

    In this study, the feasibility of an ex situ electrokinetic (EK) process combined with pre-oxidation using hydrogen peroxide (H2O2) and pre-washing using ethylenediaminetetraacetic acid (EDTA) was investigated in enhancing the extraction of Cu, Pb, and Zn from actual dredged harbor sediment. H2O2 pre-oxidation led to a change in the fractionation of Cu bound to organic matter and the sulfide fraction in the Fe-Mn oxides to the exchangeable fraction, but was not effective at removing metals. In contrast, EDTA pre-washing changed the Fe-Mn oxide-bound fractions of Cu and Pb into easily extractable fractions; 20.1, 27.5, and 32.8% of Cu, Pb, and Zn were removed, respectively. During EK treatment, metals were transported toward the anode by electromigration of negatively charged complexes such as metal-EDTA and metal-citrate. However, EK treatment did not significantly enhance the removal of metals because metals accumulated near the anodic region with an increase in the exchangeable fraction due to the short EK operating duration and low voltage gradient. Therefore, it is necessary to extend the EK operating duration and/or increase the voltage gradient for effective transportation and removal of metals from sediment.

  11. Metal extraction by Alyssum serpyllifolium ssp. lusitanicum on mine-spoil soils from Spain.

    Science.gov (United States)

    Kidd, P S; Monterroso, C

    2005-01-05

    The efficiency of Alyssum serpyllifolium ssp. lusitanicum (Brassicaceae) for use in phytoextraction of polymetallic contaminated soils was evaluated. A. serpyllifolium was grown on two mine-spoil soils (MS1 and MS2): MS1 is contaminated with Cr (283 mg kg(-1)) and MS2 is moderately contaminated with Cr (263 mg kg(-1)), Cu (264 mg kg(-1)), Pb (1433 mg kg(-1)) and Zn (377 mg kg(-1)). Soils were limed to about pH 6.0 (MS1/Ca and MS2/Ca) or limed and amended with NPK fertilisers (MS1/NPK and MS2/NPK). Biomass was reduced on MS2/Ca due to Cu phytotoxicity. Fertilisation increased biomass by 10-fold on MS1/NPK, but root growth was reduced by 7-fold compared with MS1/Ca. Plants accumulated Mn, Ni and Zn in shoots, and both metal content and transportation were generally greater in MS2 than in MS1. Zinc bioaccumulation factors (BF, shoot([metal])/soil([metal])) were significantly greater in MS2 than in MS1. However, metal yields were greatest in plants grown on MS1/NPK. Concentrations of EDTA-, NH(4)Cl- and Mehlich 3 (M3)-extractable Mn and Zn were greater after plant growth. Concentrations of M3-extractable Cr, Ni, Pb and Zn were increased at the rhizosphere. Sequential extractions showed changes in the metal distribution among different soil fractions after growth. This could reflect the buffering capacity of these soils or the plants' ability to mobilise metals from less plant-available soil pools. Results suggest that A. serpyllifolium could be suitable for phytoextraction uses in polymetallic-contaminated soils, provided Cu concentrations were not phytotoxic. However, further optimisation of growth and metal extraction are required.

  12. [Traditional and microwave acid extraction of heavy metals from MSWI fly ash and their redistribution of fractions].

    Science.gov (United States)

    Xue, Jun; Wang, Wei; Wang, Qun-hui

    2008-02-01

    HCl was used as extractant to leach Cd, Cr, Cu, Mn, Ni, Pb and Zn from municipal solid waste incinerator (MSWI) fly ash under traditional and microwave acid extraction conditions. The redistributions of heavy metals were determined using the sequential extraction procedure before and after extraction. The extraction efficiencies and speciation transformation of heavy metals were investigated. The result indicated that acid extraction can extract heavy metals effectively and extraction efficiencies of heavy metals following the sequence of Zn approximately Pb > Cd > Mn > Cu > Cr > Ni. The microwave energy can improve the extraction efficiencies evidently. By the treatment with 1 mol/L HCl, 80.17% of Cd, 15.05% of Cr, 58.25% of Cu, 62.42% of Mn, 8.88% of Ni, 89.25% of Pb and 93.03% of Zn were extracted under the condition of L/S at 25 mL/g fly ash, radiation time at 7 min. The results of sequential extraction procedure reveal that fractions of exchangeable, carbonate, Fe-Mn oxide decreased significantly after acid extraction and the remaining heavy metals mostly bound to residual form. Acid extraction process can increase the environmental safety of fly ash.

  13. Reversed micellization in metal-organophosphorus extractant systems of commercial importance

    Energy Technology Data Exchange (ETDEWEB)

    Gaonkar, A.G.; Neuman, R.D.

    1986-01-01

    The interfacial tension behavior in liquid/liquid organophosphorus extractant systems containing di(2-ethylhexyl)phosphoric acid (HDEHP) and metal ions such as Ca/sup 2 +/, Cu/sup 2 +/, Co/sup 2 +/, Ni/sup 2 +/, or Zn/sup 2 +/ was investigated. Data of vapor pressure osmometry and Karl Fischer titrimetry, in addition to those of interfacial tension, distribution equilibria and extraction kinetics, support the view that reversed micelles can form in extraction systems which employ HDEHP. 24 refs., 7 figs.

  14. Combined Application of QEM-SEM and Hard X-ray Microscopy to Determine Mineralogical Associations and Chemcial Speciation of Trace Metals

    Energy Technology Data Exchange (ETDEWEB)

    M Grafe; M Landers; R Tappero; P Austin; B Gan; A Grabsch; C Klauber

    2011-12-31

    We describe the application of quantitative evaluation of mineralogy by scanning electron microscopy in combination with techniques commonly available at hard X-ray microprobes to define the mineralogical environment of a bauxite residue core segment with the more specific aim of determining the speciation of trace metals (e.g., Ti, V, Cr, and Mn) within the mineral matrix. Successful trace metal speciation in heterogeneous matrices, such as those encountered in soils or mineral residues, relies on a combination of techniques including spectroscopy, microscopy, diffraction, and wet chemical and physical experiments. Of substantial interest is the ability to define the mineralogy of a sample to infer redox behavior, pH buffering, and mineral-water interfaces that are likely to interact with trace metals through adsorption, coprecipitation, dissolution, or electron transfer reactions. Quantitative evaluation of mineralogy by scanning electron microscopy coupled with micro-focused X-ray diffraction, micro-X-ray fluorescence, and micro-X-ray absorption near edge structure (mXANES) spectroscopy provided detailed insights into the composition of mineral assemblages and their effect on trace metal speciation during this investigation. In the sample investigated, titanium occurs as poorly ordered ilmenite, as rutile, and is substituted in iron oxides. Manganese's spatial correlation to Ti is closely linked to ilmenite, where it appears to substitute for Fe and Ti in the ilmenite structure based on its mXANES signature. Vanadium is associated with ilmenite and goethite but always assumes the +4 oxidation state, whereas chromium is predominantly in the +3 oxidation state and solely associated with iron oxides (goethite and hematite) and appears to substitute for Fe in the goethite structure.

  15. Metal-organic framework templated inorganic sorbents for rapid and efficient extraction of heavy metals.

    Science.gov (United States)

    Abney, C W; Gilhula, J C; Lu, K; Lin, W

    2014-12-17

    An innovative wet-treatment with Na2 S transforms two indium metal-organic frameworks (MOFs) into a series of porous inorganic sorbents. These MOF-templated materials display remarkable affinity for heavy metals with saturation occurring in less than 1 h. The saturation capacity for Hg(II) exceeds 2 g g(-1) , more than doubling the best thiol-functionalized sorbents in the literature.

  16. Availability of heavy metals in contaminated soil evidenced by chemical extractants

    Directory of Open Access Journals (Sweden)

    Maria Ligia de Souza Silva

    2012-06-01

    Full Text Available Heavy metals have been accumulating in Brazilian soils, due to natural processes, such as atmospheric deposition, or human industrial activities. For certain heavy metals, when in high concentrations in the soil, there is no specific extractant to determine the availability of these elements in the soil. The objective of the present study was to evaluate the availability of Cd, Cu, Fe, Mn, Pb and Zn for rice and soybeans, using different chemical extractants. In this study we used seven soil samples with different levels of contamination, in completely randomized experimental design with four replications. We determined the available concentrations of Cd, Cu, Fe, Mn, Pb and Zn extracted by Mehlich-1, HCl 0.1 mol L-1, DTPA, and organic acid extractants and the contents in rice and soybeans, which extracts were analyzed by ICP-OES. It was observed that Mehlich-1, HCl 0.1 mol L-1 and DTPA extractants were effective to assess the availability of Cd, Cu, Pb and Zn for rice and soybeans. However, the same was not observed for the organic acid extractant.

  17. Comparison of sequential and single extraction in order to estimate environmental impact of metals from fly ash

    Directory of Open Access Journals (Sweden)

    Tasić Aleksandra M.

    2016-01-01

    Full Text Available The aim of this paper was to simulate leaching of metals from fly ash in different environmental conditions using ultrasound and microwave-assisted extraction techniques. Single-agent extraction and sequential extraction procedures were used to determine the levels of different metals leaching. The concentration of metals (Al, Fe, Mn, Cd, Co, Cr, Ni, Pb, Cu, As, Be in fly ash extracts were measured by Inductively Coupled Plasma-Atomic Emission Spectrometry. Single-agent extractions of metals were conducted during sonication times of 10, 20, 30, 40 and 50 min. Single-agent extraction with deionized water was also undertaken by exposing samples to microwave radiation at the temperature of 50°C. The sequential extraction was undertaken according to the BCR procedure which was modified and applied to study the partitioning of metals in coal fly ash. The microwave-assisted sequential extraction was performed at different extraction temperatures: 50, 100 and 150°C. The partitioning of metals between the individual fractions was investigated and discussed. The efficiency of the extraction process for each step was examined. In addition, the results of the microwave-assisted sequential extraction are compared to the results obtained by standard ASTM method. The mobility of most elements contained in fly ash is markedly pH sensitive. [Projekat Ministarstva nauke Republike Srbije, br. 172030, br. 176006 i br. III43009

  18. Emerging Technology Summary. ACID EXTRACTION TREATMENT SYSTEM FOR TREATMENT OF METAL CONTAMINATED SOILS

    Science.gov (United States)

    The Acid Extraction Treatment System (AETS) is intended to reduce the concentrations and/or teachability of heavy metals in contaminated soils so the soil can be returned to the site from which it originated. The objective of the project was to determine the effectiveness and com...

  19. Aggregation and metal ion extraction properties of novel, silicon-substituted alkylenediphosphonic acids.

    Energy Technology Data Exchange (ETDEWEB)

    McAlister, D. R.; Dietz, M. L.; Chiarizia, R.; Herlinger, A. W.

    2001-05-10

    In conjunction with efforts to develop novel actinide extractants exhibiting solubility in supercritical carbon dioxide, the effect of adding silicon-based functionalities to diphosphonic acids has been investigated. Specifically, a series of silyl-substituted diphosphonic acids has been prepared and characterized, and their aggregation and metal ion extraction properties compared with alkyl-substituted diphosphonic acids, reagents previously demonstrated to be effective extractants of actinides from acidic aqueous media into various organic solvents. In addition, the influence of the number of methylene groups bridging the phosphorus atoms of the diphosphonic acids on their extraction behavior has been investigated. Variations in the extraction behavior of the compounds arising from differences in the number of bridging methylene groups have been shown to be attributable to a combination of factors, in particular, the aggregation state of the ligand, the size of the chelate rings formed upon complexation, the basicity of the phosphoryl group and the relative acidities of the ligands.

  20. Extraction of heavy metals from contaminated soil by Cinnamomum camphora.

    Science.gov (United States)

    Ho, Jian-Ren; Ma, Hwong-Wen; Wang, Yi-Chung; Ko, Chun-Han; Chang, Fang-Chih; Feng, Fong-Long; Wang, Ya-Nang

    2014-12-01

    83 acres of rice paddy fields in Taoyuan county, Taiwan, were polluted by cadmium (Cd), chromium (Cr) and copper (Cu) through a nearby irrigation channel, and rice plantation was ceased in 1987. Camphor trees (Cinnamomum camphora) have been planted in 2 acre of the above fields since 1991. Heavy metal accumulation of roots, leaves, branches and heartwood of camphor trees were analyzed during 20-year afforestation. Averaged Cd contents of the roots were found larger than the ones of the branches, leaves, sapwood and heartwood of camphor trees growing in three polluted plots. Averaged diameters at breast height (DBH) of the planted camphor trees were 13-15 cm. Cd pollution did not significantly impact the growth of camphor trees, as similar DBH's were found from both polluted and control sites. Annual growths of DBH were from 0.63 to 0.77 cm year(-1). Planting camphor trees sequestered 68.8 ton biomass per acre. During 20-year period, 0.69-1.98 ton C year(-1) ha(-1) were sequestered on three polluted plots. The above numbers exceeded IPCC LULUCF reference values 0.31-0.53 ton C year(-1) ha(-1) for activities at forest lands.

  1. Towards to Extraction of Nanodispersed Noble Metals From Natural Black Graphite Shales

    Directory of Open Access Journals (Sweden)

    Elena A. Mikhailenko

    2012-01-01

    Full Text Available A theoretical approach based on the density functional theory and the pseudopotential method was applied to consider diffusion and accumulation of Au, Pt, and Pd in graphite. It is shown that Pt atoms migrate easily inside graphite. They can stop at structure defects and accumulate there, attracting each other and forming plate clusters. Atoms of gold do not penetrate into graphite but link with edge atoms of broken graphite crystallites, forming three-dimensional metallic particles. Palladium behavior is intermediate between platinum and gold. Addition of silicon into graphite can promote the extraction of noble metals because Si atoms force out Pt, Pd, and Au atoms from their bonded states. Last effect can be used as a mechanism of striking off metals from graphite and their extraction from shales

  2. Macroporous monoliths for trace metal extraction from seawater

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Yanfeng; Mayes, Richard; Gill, Gary A.; Kuo, Li-Jung; Wood, Jordana R.; Binder, Andrew; Brown, Suree; Dai, Sheng

    2015-05-29

    The viability of seawater-based uranium recovery depends on the uranium adsorption rate and capacity, since the concentration of uranium in the oceans is relatively low (3.3 μgL⁻¹). An important consideration for a fast adsorption is to maximize the adsorption properties of adsorbents such as surface areas and pore structures, which can greatly improve the kinetics of uranium extraction and the adsorption capacity simultaneously. Following this consideration, macroporous monolith adsorbents were prepared from the copolymerization of acrylonitrile (AN) and N,N’-methylenebis(acrylamide) (MBAAm) based on a cryogel method using both hydrophobic and hydrophilic monomers. The monolithic sorbents were tested with simulated seawater containing a high uranyl concentration (–6 ppm) and the uranium adsorption results showed that the adsorption capacities are strongly influenced by the ratio of monomer to the crosslinker, i.e., the density of the amidoxime groups. The preliminary seawater testing indicates the high salinity content of seawater does not hinder the adsorption of uranium.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-04-15

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

  4. Measuring the noble metal and iodine composition of extracted noble metal phase from spent nuclear fuel using instrumental neutron activation analysis.

    Science.gov (United States)

    Palomares, R I; Dayman, K J; Landsberger, S; Biegalski, S R; Soderquist, C Z; Casella, A J; Brady Raap, M C; Schwantes, J M

    2015-04-01

    Masses of noble metal and iodine nuclides in the metallic noble metal phase extracted from spent fuel are measured using instrumental neutron activation analysis. Nuclide presence is predicted using fission yield analysis, and radionuclides are identified and the masses quantified using neutron activation analysis. The nuclide compositions of noble metal phase derived from two dissolution methods, UO2 fuel dissolved in nitric acid and UO2 fuel dissolved in ammonium-carbonate and hydrogen-peroxide solution, are compared.

  5. Separation and Recovery of Precious Metals from Leach Liquors of Spent Electronic Wastes by Solvent Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Thi Hong; Wang, Lingyun; Lee, Man Seung [Mokpo National University, Mokpo (Korea, Republic of)

    2017-04-15

    Solvent extraction was employed to recover precious metals (Au (III), Pd (II) and Pt (IV)) from the leach solution of spent electronic wastes containing Cu (II), Cr (III) and Fe (III). First, pure Fe (III) and Au (III) were recovered by simultaneous extraction with Cyanex 923 followed by selective stripping with HCl and Na{sub 2}S{sub 2}O{sub 3}. Second, Pt (IV), Pd (II) and Cu (II) were extracted by Alamine 336 from the raffinate. After the removal of Cu (II) by stripping with weak HCl, Pd (II) and Pt (IV) were separately stripped by controlling the concentration of thiourea in the mixture with HCl. A process flow sheet for the separation of precious metals was proposed.

  6. Comparing Methods for Extracting Heavy Metals from Histosols for Establishing Quality Reference Values

    Directory of Open Access Journals (Sweden)

    Erica Souto Abreu Lima

    Full Text Available ABSTRACT The diversity of methods for heavy metal extraction from soils complicates comparison of results used by environmental agencies to establish quality reference values. The aim of this study was to evaluate three soil digestion methods regarding the solubilizing capacity of Ba, Cr, Cu, Fe, Mn, Ni, Pb and Zn, and to propose a standard method to establish Quality Reference Values (QRVs for Brazilian Histosols. Twenty soil samples were selected to evaluate the USEPA 3051, USEPA 3051A and Aqua Regia methods in a closed system. The methods tested were statistically similar regarding Cu, Fe and Mn extraction from soils. However, the methods can not be considered similar for Ba, Cr, Ni, Pb and Zn; Aqua Regia recorded the highest levels, except for Ba. The Aqua Regia method proved suitable for metal extraction from soils with organic characteristics and can be used to establish QRVs.

  7. Characterization of low alloy ferritic steel–Ni base alloy dissimilar metal weld interface by SPM techniques, SEM/EDS, TEM/EDS and SVET

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Siyan; Ding, Jie; Ming, Hongliang; Zhang, Zhiming; Wang, Jianqiu, E-mail: wangjianqiu@imr.ac.cn

    2015-02-15

    The interface region of welded A508–Alloy 52 M is characterized by scanning probe microscope (SPM) techniques, scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM)/Energy Dispersive Spectroscopy (EDS) and scanning vibrate electrode technique (SVET). The regions along the welded A508–Alloy 52 M interface can be categorized into two types according to their different microstructures. In the type-I interface region, A508 and Alloy 52 M are separated by the fusion boundary, while in the type-II interface region, A508 and Alloy 52 M are separated by a martensite zone. A508, martensite zone and grain boundaries in Alloy 52 M are ferromagnetic while the Alloy 52 M matrix is paramagnetic. The Volta potentials measured by scanning Kelvin probe force microscopy (SKPFM) of A508, martensite zone and Alloy 52 M follow the order: V{sub 52} {sub M} > V{sub A508} > V{sub martensite}. The corrosion behavior of A508–Alloy 52 M interface region is galvanic corrosion, in which Alloy 52 M is cathode while A508 is anode. The martensite dissolves faster than Alloy 52 M, but slower than A508 in the test solution. - Highlights: • The A508–Alloy 52 M interface regions can be categorized into two types. • The chromium depleted region is observed along the Alloy 52 M grain boundary. • The Alloy 52 M grain boundaries which are close to the interface are ferromagnetic. • Martensite zone has lower Volta potential but higher corrosion resistance than A508.

  8. Aβ1-16 conformational changes induced by heavy metals, antioxidants, and corn zeins: CD, AFM, SEM, and FT-IR studies

    Science.gov (United States)

    Murariu, Manuela; Mihai, Marcela; Zaharia, Marius; Drochioiu, Gabi

    2014-10-01

    Amyloid-beta (known also as Aβ or A-beta or beta-amyloid) is a peptide of 36-43 amino acids that appears to be the main constituent of amyloid plaques in the brains of Alzheimer's disease (AD) patients. The transformation process from α-helix to β-sheet structures appears to be one of the major factors in the genesis and evolution of a variety of neurodegenerative diseases such as AD, Parkinson's disease (PD), and several prion diseases [1,2]. Metal-based reactions of some polypeptides and proteins are considered as a common denominator for neurodegenerative diseases (Figure 1) [3,4]. Amyloid-β (Aβ) aggregates are associated with Alzheimer's disease (AD), and may be promoted by the trace amounts of metal ions like aluminium, iron, zinc or copper [5-11]. For example, copper ions cause the peptide aggregation to a great extent and highly increase the neurotoxicity exhibited by Aβ1-40 in cell culture [11].

  9. SEM microcharacterization of semiconductors

    CERN Document Server

    Holt, D B

    1989-01-01

    Applications of SEM techniques of microcharacterization have proliferated to cover every type of material and virtually every branch of science and technology. This book emphasizes the fundamental physical principles. The first section deals with the foundation of microcharacterization in electron beam instruments and the second deals with the interpretation of the information obtained in the main operating modes of a scanning electron microscope.

  10. Endoscopic extra-cavitary drainage of pancreatic necrosis with fully covered self-expanding metal stents (fcSEMS) and staged lavage with a high-flow water jet system.

    Science.gov (United States)

    Smith, Ioana B; Gutierrez, Juan P; Ramesh, Jayapal; Wilcox, C Mel; Mönkemüller, Klaus E

    2015-04-01

    To present a novel, less-invasive method of endoscopic drainage (ED) for walled-off pancreatic necrosis (WON).We describe the feasibility, success rate, and complications of combined ED extra-cavitary lavage and debridement of WON using a biliary catheter and high-flow water jet system (water pump). Endoscopic ultrasound (EUS)-guided drainage was performed with insertion of two 7-Fr, 4-cm double pigtail stents. Subsequently a fully covered self-expanding metal stent (fcSEMS) was placed. The key aspect of the debridement was the insertion of a 5-Fr biliary catheter through or along the fcSEMS into the cavity, with ensuing saline lavage using a high-flow water jet system. The patients were then brought back for repeated, planned endoscopic lavages of the WON. No endoscopic intra-cavitary exploration was performed. A total of 17 patients (15 men, 2 women; mean age 52.6, range 24 - 69; mean American Society of Anesthesiologists [ASA] score of 3) underwent ED of WON with this new method. The mean initial WON diameter was 9.5 cm, range 8 to 26 cm. The total number of ED was 84, range 2 to 13. The mean stenting period was 42.5 days. The mean follow-up was 51 days, range 3 to 370. A resolution of the WON was achieved in 14 patients (82.3 %). There were no major complications associated with this method. ED of complex WON with fcSEMS followed by repeated endoscopic extra-cavitary lavage and debridement using a biliary catheter and high-flow water jet system is a minimally invasive, feasible method with high technical and clinical success and minimal complications.

  11. Phytochemicals and heavy metals analysis of methanolic extract of edible mushrooms collected from Karak District, Khyber Pakhtunkhwa, Pakistan

    OpenAIRE

    Farhan; Hameed Ur Rehman; Sajid Awais; Nisar Ahmad; Baharullah Khattak

    2016-01-01

    Objective: To qualitatively evaluate the phytochemicals and quantitatively determine the heavy metals of three species of edible mushrooms collected from the Karak area of Khyber Pukhtoonkhwa, Pakistan. Methods: The plant sample was subjected to methanolic extraction. The extraction was then concentrated by using rotary evaporator. The methanolic extract was screened for the qualitative study of various phytochemicals and quantitative measurement of heavy metals. Results: A ...

  12. Role of reducing agent in extraction of arsenic and heavy metals from soils by use of EDTA.

    Science.gov (United States)

    Kim, Eun Jung; Jeon, Eun-Ki; Baek, Kitae

    2016-06-01

    Although many metal-contaminated sites contain both anionic arsenic and cationic heavy metals, the current remediation technologies are not effective for the simultaneous removal of both anionic and cationic elements from the contaminated sites due to their different characteristics. In this study, the role of reducing agent in simultaneous extraction of As, Cu, Pb, and Zn from contaminated soils was investigated using EDTA. The addition of reducing agents, which includes sodium oxalate (Na2C2O4), ascorbic acid (C6H8O6) and sodium dithionite (Na2S2O4), greatly enhanced the EDTA extraction of both As and heavy metals from the contaminated soils due to the increased mobility of the metals under the reduced conditions. The extent of the enhancement of the EDTA extraction was greatly affected by the reducing conditions. Strong reducing conditions (0.1 M of dithionite) were required for the extraction of metals strongly bound to the soil, while weak reducing conditions (0.01 M of dithionite or 0.1 M of oxalate/ascorbic acid) were sufficient for extraction of metals that were relatively weakly bound to the soil. An almost 90% extraction efficiency of total metals (As, Cu, Zn, and Pb) was obtained from the contaminated soils using the combination of dithionite and EDTA. Our results clearly showed that the combination of dithionite and EDTA can effectively extract As and heavy metals simultaneously from soils under a wide range of pH conditions.

  13. Extraction of heavy metals from e-waste contaminated soils using EDDS

    Institute of Scientific and Technical Information of China (English)

    Renxiu Yang; Chunling Luo; Gan Zhang; Xiangdong Li; Zhenguo Shen

    2012-01-01

    Environmental contamination due to uncontrolled e-waste recycling activities is drawing increasing attention in the world.Extraction of these metals with biodegradable chelant [S,S]-ethylenediaminedisuccinic acid (EDDS) and the factors influencing extraction efficacy were investigated in the present study.Results showed that the addition of EDDS at low pH (5.5) produced higher metal extraction than that at high pH (8.0) solution.Metal speciation analysis indicated that Cu was completely complexed with EDDS at different pH conditions with various amounts of EDDS applied.For Pb and Zn,at low EDDS dose of 0.304 mol/kg soil,they were present as Pband Zn-EDDS.However,at high EDDS dose of 1.26 mol/kg soil,most of Pb was bound with dissolved organic matter.Ca and A1 were found to be strong competitors for trace metals to EDDS at low application dose and low pH condition.

  14. Extraction of heavy metals from e-waste contaminated soils using EDDS.

    Science.gov (United States)

    Yang, Renxiu; Luo, Chunling; Zhang, Gan; Li, Xiangdong; Shen, Zhenguo

    2012-01-01

    Environmental contamination due to uncontrolled e-waste recycling activities is drawing increasing attention in the world. Extraction of these metals with biodegradable chelant [S,S]-ethylenediaminedisuccinic acid (EDDS) and the factors influencing extraction efficacy were investigated in the present study. Results showed that the addition of EDDS at low pH (5.5) produced higher metal extraction than that at high pH (8.0) solution. Metal speciation analysis indicated that Cu was completely complexed with EDDS at different pH conditions with various amounts of EDDS applied. For Pb and Zn, at low EDDS dose of 0.304 mol/kg soil, they were present as Pb- and Zn-EDDS. However, at high EDDS dose of 1.26 mol/kg soil, most of Pb was bound with dissolved organic matter. Ca and Al were found to be strong competitors for trace metals to EDDS at low application dose and low pH condition.

  15. Effect of heavy metal-solubilizing microorganisms on zinc and cadmium extractions from heavy metal contaminated soil with Tricholoma lobynsis.

    Science.gov (United States)

    Ji, Ling-yun; Zhang, Wei-wei; Yu, Dong; Cao, Yan-ru; Xu, Heng

    2012-01-01

    The macrofungus, Tricholoma lobynsis, was chosen to remedy Zn-Cd-Pb contaminated soil. To enhance its metal-extracting efficiency, two heavy metal resistant microbes M6 and K1 were applied owing to their excellent abilities to solubilize heavy metal salts. The two isolated microbial strains could also produce indole acetic acid (IAA), siderophore and solubilize inorganic phosphate, but neither of them showed 1-aminocyclopropane-1-carboxylate deaminase activity. The strains M6 and K1 were identified as Serratia marcescens and Rhodotorula mucilaginosa based on 16S rDNA and ITS sequence analysis respectively. Pot experiment showed that spraying to T. lobynsis-inoculated soil with M6 and K1 respectively could increase total Cd accumulations of this mushroom by 216 and 61%, and Zn by 153 and 49% compared to the uninoculated control. Pb accumulation however, was too low (metal-accumulating abilities of macrofungi and IAA-siderophore production, phosphate solubilization abilities of the assisted-microbes. This kind of macrofungi-microbe interaction can be developed into a novel bioremediation strategy.

  16. Liquid phase micro-extraction: Towards the green methodology for ultratrace metals determination in aquatic ecosystems

    Directory of Open Access Journals (Sweden)

    López-López J. A.

    2013-04-01

    Full Text Available Heavy metals are normally found, in natural waters, in very low concentrations. Some of them are essential for life in low level; however, in higher level they are toxic. Therefore, analyzing their bio-available fraction is of main interest. Standard methodology is based in the collection of a number of samples from a water body. Collected samples must be stored, pre-treated and then analyzed. Pre-treatment usually involves pre-concentrating the metal, with the corresponding risk of contamination or loss of analyte. This way, punctual information is obtained from every sampling campaign. As an alternative, passive sampling techniques allow the continuous and coupled sampling-pre-treatment for heavy metals analysis, giving a better approach in the characterization of the studied water body. Liquid phase micro-extraction (LPME is a green analytical alternative for liquid-liquid extraction that promotes a reduction of sample volume, solvent needed and waste generation. Using these systems, polypropylene hollow fibers (HF with pores in their walls can be used. A few micro-liters of organic solvent are supported in the pores. The sample is placed in the outer part of the fiber and a receiving phase is placed in its inner part, allowing continuous liquid extraction of the metal from the sample. Several fibers with different physical features have been employed to analyzed total concentration and bio-availability of some heavy metals (Ag, Ni, Cu in natural water samples. Thanks to fibers configuration, devices for passive sampling based in HF-LPME could be designed. Advantages of this methodology over existing ones are supported because the receiving phase is liquid. As a consequence, retained metals do not need to be eluted from the acceptor prior to instrumental analysis.

  17. Comparison of Gastric versus Gastrointestinal PBET Extractions for Estimating Oral Bioaccessibility of Metals in House Dust.

    Science.gov (United States)

    Boros, Kristina; Fortin, Danielle; Jayawardene, Innocent; Chénier, Marc; Levesque, Christine; Rasmussen, Pat E

    2017-01-18

    Oral bioaccessibility estimates for six metals which are prevalent as contaminants in Canada (zinc, lead, cadmium, copper, nickel, and chromium) are investigated for house dust using the simple gastric phase versus the two-phase physiologically-based extraction technique (PBET). The purpose is to determine whether a complete gastrointestinal (GI) assay yields a more conservative (i.e., higher) estimate of metal bioaccessibility in house dust than the gastric phase alone (G-alone). The study samples include household vacuum dust collected from 33 homes in Montreal, Canada, plus four certified reference materials (NIST 2583, NIST 2584, NIST 2710 and NIST 2710a). Results indicate that percent bioaccessibilities obtained using G-alone are generally greater than or equivalent to those obtained using the complete GI simulation for the six studied metals in house dust. Median bioaccessibilities for G-alone/GI in household vacuum dust samples (n = 33) are 76.9%/19.5% for zinc, 50.4%/6.2% for lead, 70.0%/22.4% for cadmium, 33.9%/30.5% for copper and 28.5%/20.7% for nickel. Bioaccessible chromium is above the detection limit in only four out of 33 samples, for which G-alone results are not significantly different from GI results (p = 0.39). It is concluded that, for the six studied metals, a simple G-alone extraction provides a conservative and cost-effective approach for estimating oral bioaccessibility of metals in house dust.

  18. Comparison of Gastric versus Gastrointestinal PBET Extractions for Estimating Oral Bioaccessibility of Metals in House Dust

    Science.gov (United States)

    Boros, Kristina; Fortin, Danielle; Jayawardene, Innocent; Chénier, Marc; Levesque, Christine; Rasmussen, Pat E.

    2017-01-01

    Oral bioaccessibility estimates for six metals which are prevalent as contaminants in Canada (zinc, lead, cadmium, copper, nickel, and chromium) are investigated for house dust using the simple gastric phase versus the two-phase physiologically-based extraction technique (PBET). The purpose is to determine whether a complete gastrointestinal (GI) assay yields a more conservative (i.e., higher) estimate of metal bioaccessibility in house dust than the gastric phase alone (G-alone). The study samples include household vacuum dust collected from 33 homes in Montreal, Canada, plus four certified reference materials (NIST 2583, NIST 2584, NIST 2710 and NIST 2710a). Results indicate that percent bioaccessibilities obtained using G-alone are generally greater than or equivalent to those obtained using the complete GI simulation for the six studied metals in house dust. Median bioaccessibilities for G-alone/GI in household vacuum dust samples (n = 33) are 76.9%/19.5% for zinc, 50.4%/6.2% for lead, 70.0%/22.4% for cadmium, 33.9%/30.5% for copper and 28.5%/20.7% for nickel. Bioaccessible chromium is above the detection limit in only four out of 33 samples, for which G-alone results are not significantly different from GI results (p = 0.39). It is concluded that, for the six studied metals, a simple G-alone extraction provides a conservative and cost-effective approach for estimating oral bioaccessibility of metals in house dust.

  19. Comparison of Gastric versus Gastrointestinal PBET Extractions for Estimating Oral Bioaccessibility of Metals in House Dust

    Directory of Open Access Journals (Sweden)

    Kristina Boros

    2017-01-01

    Full Text Available Oral bioaccessibility estimates for six metals which are prevalent as contaminants in Canada (zinc, lead, cadmium, copper, nickel, and chromium are investigated for house dust using the simple gastric phase versus the two-phase physiologically-based extraction technique (PBET. The purpose is to determine whether a complete gastrointestinal (GI assay yields a more conservative (i.e., higher estimate of metal bioaccessibility in house dust than the gastric phase alone (G-alone. The study samples include household vacuum dust collected from 33 homes in Montreal, Canada, plus four certified reference materials (NIST 2583, NIST 2584, NIST 2710 and NIST 2710a. Results indicate that percent bioaccessibilities obtained using G-alone are generally greater than or equivalent to those obtained using the complete GI simulation for the six studied metals in house dust. Median bioaccessibilities for G-alone/GI in household vacuum dust samples (n = 33 are 76.9%/19.5% for zinc, 50.4%/6.2% for lead, 70.0%/22.4% for cadmium, 33.9%/30.5% for copper and 28.5%/20.7% for nickel. Bioaccessible chromium is above the detection limit in only four out of 33 samples, for which G-alone results are not significantly different from GI results (p = 0.39. It is concluded that, for the six studied metals, a simple G-alone extraction provides a conservative and cost-effective approach for estimating oral bioaccessibility of metals in house dust.

  20. Viewing Integrated-Circuit Interconnections By SEM

    Science.gov (United States)

    Lawton, Russel A.; Gauldin, Robert E.; Ruiz, Ronald P.

    1990-01-01

    Back-scattering of energetic electrons reveals hidden metal layers. Experiment shows that with suitable operating adjustments, scanning electron microscopy (SEM) used to look for defects in aluminum interconnections in integrated circuits. Enables monitoring, in situ, of changes in defects caused by changes in temperature. Gives truer picture of defects, as etching can change stress field of metal-and-passivation pattern, causing changes in defects.

  1. Space Experiment Module (SEM)

    Science.gov (United States)

    Brodell, Charles L.

    1999-01-01

    The Space Experiment Module (SEM) Program is an education initiative sponsored by the National Aeronautics and Space Administration (NASA) Shuttle Small Payloads Project. The program provides nationwide educational access to space for Kindergarten through University level students. The SEM program focuses on the science of zero-gravity and microgravity. Within the program, NASA provides small containers or "modules" for students to fly experiments on the Space Shuttle. The experiments are created, designed, built, and implemented by students with teacher and/or mentor guidance. Student experiment modules are flown in a "carrier" which resides in the cargo bay of the Space Shuttle. The carrier supplies power to, and the means to control and collect data from each experiment.

  2. Preliminary Phytochemical Screening and Heavy Metal Analysis of Leaf Extracts of Ziziphus oenoplia (L Mill. Gard

    Directory of Open Access Journals (Sweden)

    M Lalitha Eswari

    2013-01-01

    Full Text Available The present study was aimed to investigate the preliminary phytochemical screening of the leaves of Ziziphus oenoplia belonging to family Rhamnaceae. The dried leaves of the plant were subjected to successive Soxhlet extraction by continuous hot percolation method using organic solvents of increasing polarity such as petroleum ether, ethyl acetate and ethanol. The aqueous extract was prepared by cold maceration technique. All the extracts were subjected to qualitative phytochemical screening and it showed the presence of active constituents such as alkaloid, flavonoid, phenol and triterpenoid. Quantitative determination of alkaloid was done by Harborne (1973 method, whereas total Phenolic content was determined by Folin-ciocalteu method and total Flavonoid were determined by the aluminium chloride colorimetric method. Heavy metals and inorganic elements are determined by inductively coupled plasma optical emission spectrometry technique. The results obtained shows that the extracts contain medicinally important bioactive constituents and also heavy metals present in the plant extracts were within the permissible limits. This justifies its use in the traditional medicine for the treatment of different diseases such as ulcer, asthma, dysentery and fever.

  3. Rare earth elements and critical metal content of extracted landfilled material and potential recovery opportunities

    Energy Technology Data Exchange (ETDEWEB)

    Gutiérrez-Gutiérrez, Silvia C.; Coulon, Frédéric; Jiang, Ying; Wagland, Stuart, E-mail: s.t.wagland@cranfield.ac.uk

    2015-08-15

    Highlights: • Samples from multiple core drills were obtained from 4× landfill sites in the UK. • Each sample analysed for rare earth elements, critical metals and valuable metals. • Two stage microwave digestion method ensuring high yield. • High quantities of copper and aluminium were observed in the soil layers of landfill. • Across 4× landfills aluminium and copper present has a value of around $400 million. - Abstract: Rare earth elements (REEs), Platinum group metals (PGMs) and other critical metals currently attract significant interest due to the high risks of supply shortage and substantial impact on the economy. Their uses in many applications have made them present in municipal solid waste (MSW) and in commercial and industrial waste (C&I), since several industrial processes produce by-products with high content of these metals. With over 4000 landfills in the UK alone, the aim of this study was to assess the existence of these critical metals within landfills. Samples collected from four closed landfills in UK were subjected to a two-step acid digestion to extract 27 metals of interest. Concentrations across the four landfill sites were 58 ± 6 mg kg{sup −1} for REEs comprising 44 ± 8 mg kg{sup −1} for light REEs, 11 ± 2 mg kg{sup −1} for heavy REEs and 3 ± 1 mg kg{sup −1} for Scandium (Sc) and 3 ± 1.0 mg kg{sup −1} of PGMs. Compared to the typical concentration in ores, these concentrations are too low to achieve a commercially viable extraction. However, content of other highly valuable metals (Al and Cu) was found in concentrations equating to a combined value across the four landfills of around $400 million, which increases the economic viability of landfill mining. Presence of critical metals will mainly depend on the type of waste that was buried but the recovery of these metals through landfill mining is possible and is economically feasible only if additional materials (plastics, paper, metallic items and other) are

  4. Measurements of an ion beam diameter extracted into air through a large-bore metal capillary

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Y.; Umigishi, M. [Graduate School of Humanities and Sciences, Nara Women’s University, Nara 630-8506 (Japan); Ishii, K.; Ogawa, H. [Department of Physics, Nara Women’s University, Nara 630-8506 (Japan)

    2015-07-01

    To extract an ion beam into air, the technique using a single macro-capillary has been paid attention. We have expanded the bore of the metal capillary up to 500 μm∅ inlet diameter to increase the beam intensity and have measured the intensity distributions of the extracted 3 MeV proton beam. Furthermore, we have tilted the capillary angle and measured the intensity distributions of the ion beam. In this article, we will present the experimental results together with the simulation which takes the tilt angles of the capillary into account.

  5. Extraction of metals from metal ion-catechol-quaternary base systems.

    Science.gov (United States)

    Vrchlabský, M; Sommer, L

    1968-09-01

    Methods are given for the extraction of iron(III), molybdenum(VI), titanium(IV), niobium(V), vanadium(IV), uranium(VI) and tungsten(VI) as ternary complexes with catechol and a quaternary cation such as n-butyltriphenylphosphonium, n-propyltriphenylphosphonium, tetraphenylarsonium, cetylpyridinium, cetyltrimethylammonium and 2,3,5-triphenyltetrazolium, the solvent being chloroform. By use of masking agents and pH control, some of these elements can be separated from each other by this means.

  6. Faster extraction of heavy metals from soils using vacuum and ultrasonic energy.

    Science.gov (United States)

    Pontes, Fernanda V M; Carneiro, Manuel C; de da Souza, Evelyn M F; da Silva, Lílian I D; Monteiro, Maria Inês C; Neto, Arnaldo A

    2013-01-01

    A fast vacuum- and ultrasound-assisted acid extraction of Co, Cu, Fe, Mn, Pb, and Zn from soils using a homemade system has been investigated. Preliminarily, a full factorial design with two levels and three variables (extracting agent, extraction temperature, and sonication time) was applied to optimize the extraction conditions (without vacuum) for some heavy metals (Cu, Mn, Pb, and Zn). The best results were obtained with a 3:1 HCI extraction solution, temperature of 80 degrees C, and time of 2 h. As this sonication time was too long, a vacuum pump was used to produce air bubbles in order to increase the contact between the sample and the extracting agent and to prevent the sample sedimentation. This improvement drastically reduced the sonication time to 2 min. Under these conditions, Co, Cu, Mn, and Zn were totally extracted (recoveries of 86-99%), while recoveries of 73-76 and 74% were obtained for Fe and Pb, respectively. The LOD values using flame atomic absorption spectrometry for determination of Co, Cu, Fe, Mn, Pb, and Zn were 3.2, 7.5, 37.5, 7.5, 22.5, and 3.8 micro glg, respectively. The RSDs were lower than 11% (n = 3).

  7. Relationship between heavy metals and minerals extracted from soil clay by standard and novel acid extraction procedures.

    Science.gov (United States)

    Melo, Vander Freitas; Batista, Araína Hulmann; Gilkes, Robert J; Rate, Andrew W

    2016-12-01

    Strong acid digestions are commonly used to determine heavy metal (HM) contents in soils. In order to understand more fully the acid digestion processes, a logical step is to determine the extent of dissolution of mineral phases. The aims of this study were to compare the efficiency of extraction of HM by different acid digestions and to monitor the associated dissolution of the clay fraction. The context of the study was to develop a milder chemical extraction method (microwave-assisted 1 mol L(-1) HNO3 closed system (NACS)), which recovers more reactive HM and with little dissolution of minerals. The different acid digestion methods dissolved different amounts of minerals from the clay fraction. Both aqua regia (AR) and EPA 3051 dissolved all of the Fe and Al oxides, and the dissolution of kaolin was limited to thinner particles (c dimension), smaller particles in a and b dimensions and grains with lower crystallinity. The lower recovery of HM for AR compared with EPA 3051 was related to the large amount of short-range order phases formed during the AR extraction as these phases have the capacity to re-adsorb HM. The new method (NACS) has the potential to replace other methods of determining bioavailable forms of HM, such as AR and EPA 3051. The contents of Pb, As, Co, Zn, and Cu determined by EPA 3051 and EPA 3052 were quite close.

  8. Effects of extraction methods and factors on leaching of metals from recycled concrete aggregates.

    Science.gov (United States)

    Bestgen, Janile O; Cetin, Bora; Tanyu, Burak F

    2016-07-01

    Leaching of metals (calcium (Ca), chromium (Cr), copper, (Cu), iron (Fe), and zinc (Zn)) of recycled concrete aggregates (RCAs) were investigated with four different leachate extraction methods (batch water leach tests (WLTs), toxicity leaching procedure test (TCLP), synthetic precipitation leaching procedure test (SPLP), and pH-dependent leach tests). WLTs were also used to perform a parametric study to evaluate factors including (i) effects of reaction time, (ii) atmosphere, (iii) liquid-to-solid (L/S) ratio, and (iv) particle size of RCA. The results from WLTs showed that reaction time and exposure to atmosphere had impact on leaching behavior of metals. An increase in L/S ratio decreased the effluent pH and all metal concentrations. Particle size of the RCA had impact on some metals but not all. Comparison of the leached concentrations of metals from select RCA samples with WLT method to leached concentrations from TCLP and SPLP methods revealed significant differences. For the same RCA samples, the highest metal concentrations were obtained with TCLP method, followed by WLT and SPLP methods. However, in all tests, the concentrations of all four (Cr, Cu, Fe, and Zn) metals were below the regulatory limits determined by EPA MCLs in all tests with few exceptions. pH-dependent batch water leach tests revealed that leaching pattern for Ca is more cationic whereas for other metals showed more amphoteric. The results obtained from the pH-dependent tests were evaluated with geochemical modeling (MINTEQA2) to estimate the governing leaching mechanisms for different metals. The results indicated that the releases of the elements were solubility-controlled except Cr.

  9. Selective extraction and recovery of rare earth metals from phosphor powders in waste fluorescent lamps using an ionic liquid system.

    Science.gov (United States)

    Yang, Fan; Kubota, Fukiko; Baba, Yuzo; Kamiya, Noriho; Goto, Masahiro

    2013-06-15

    The recycling of rare earth metals from phosphor powders in waste fluorescent lamps by solvent extraction using ionic liquids was studied. Acid leaching of rare earth metals from the waste phosphor powder was examined first. Yttrium (Y) and europium (Eu) dissolved readily in the acid solution; however, the leaching of other rare earth metals required substantial energy input. Ionization of target rare earth metals from the waste phosphor powders into the leach solution was critical for their successful recovery. As a high temperature was required for the complete leaching of all rare earth metals, ionic liquids, for which vapor pressure is negligible, were used as an alternative extracting phase to the conventional organic diluent. An extractant, N, N-dioctyldiglycol amic acid (DODGAA), which was recently developed, showed a high affinity for rare earth metal ions in liquid-liquid extraction although a conventional commercial phosphonic extractant did not. An effective recovery of the rare earth metals, Y, Eu, La and Ce, from the metal impurities, Fe, Al and Zn, was achieved from the acidic leach solution of phosphor powders using an ionic liquid containing DODGAA as novel extractant system.

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

    Directory of Open Access Journals (Sweden)

    D. Max Roundhill

    2009-12-01

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

  11. Groundwater quality in an abandoned metal extraction site: the case study of Campello Monti (NW Italy)

    Science.gov (United States)

    Mehta, Neha; Lasagna, Manuela; Antonella Dino, Giovanna; De Luca, Domenico Antonio

    2017-04-01

    Extractive activities present threat to natural water systems and their effects are observed even after the cessation of activities. The harmful effects of extractive activities such as deterioration of water sources by low quality waters or by allowing leaching of metals into groundwater makes it necessary to carry out careful, scientific and comprehensive studies on this subject. Consequently, the same problem statement was chosen as part of a PhD research Project. The PhD research is part of REMEDIATE project (A Marie Sklodowska-Curie Action Initial Training Network for Improved decision making in contaminated land site investigation and risk assessment, Grant Agreement No. 643087). The current work thus points out on the contamination of groundwater sources due to past mining activities in the area. Contaminated groundwater may act as possible contamination source to surface water also. The impacts on water systems connected to mining activities depend on the ore type, metal being extracted, exploitation method, ore processing, pollution control efforts, geochemical and hydrogeochemical conditions of water and surroundings. To evaluate the effects posed by past metal extracting activities the study was carried out at an abandoned site used for extracting nickel in Campello Monti (Valstrona municipality, Piedmont region, Italy). Campello Monti is located in basement of Southern Italian Alps in the Ivrea Verbano Zone. The area is composed of mafic rocks intruded by mantle periodite. The mafic formation consists of peridotites, pyroxenites, gabbros, anorthosites, gabbro-norite, gabbro-diorite and diorite. Mines were used for nickel exploitation from 9th Century and continued until 1940s. The long history of nickel extraction has left the waste contaminated with Ni and Co in the mountains alongwith tunnels used for carrying out metal extracting activities. The area around the site is used for housing, shows the presence of domestic animals and has Strona creek

  12. Development of bioleaching: proteomics and genomics approach in metals extraction process

    Directory of Open Access Journals (Sweden)

    M. Azizur Rahman

    2016-08-01

    Full Text Available Microbes are key components of the structure and function of bioleaching process. Increasing consciousness of the role of microbes has led to a quick growth of descriptive and investigational studies of their abundance and activities. However, the detail information of complex functional molecules contain in promising microbes which are very important for understanding microbial processes in bioleaching, are lacking. Therefore, molecular functions of microbes in the bioleaching process are very essential to understand about the microbial activities, especially in the process of the extraction of metals in mineral industries. In this review, the current state of proteomics and genomics of bioleaching in metals extraction processes and the major developments of these analytical methods at industrial scales are highlighted.

  13. Decontamination of Metal Ions in Soil by Supercritical CO{sub 2} Extraction with Catecholamine Ligand

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jihye; Kim, Hakwon; Park, Kwangheon [Kyunghee University, Yongin (Korea, Republic of)

    2015-10-15

    The role of fuel cladding and reactor vessels is to help prevent the leakage of radioactive materials, including the fission products. However, if these shielding materials are damaged by a severe disaster such as the Fukushima Accident, radioactive materials could leak outside of a power plant site. Indeed, after the Fukushima Accident, radioactive materials have been detected in air and water samples. The air and water pollution lead to soil pollution, which is particularly difficult to decontaminate, as soil pollution has several types that vary according to the characteristics of a pollutant or its area. The existing decontamination methods generate a secondary waste owing to use of chemical toxicity solvents. It is also disadvantageous due to the additional cost of handling them. Therefore, new effective decontamination methods that reduce the use of toxicity solvents are necessary. For example, using supercritical CO{sub 2} has been studied as a new decontamination method. This study examines the method of decontaminating metallic ions inside of the soil using supercritical CO{sub 2} and a catecholamine compound. This study examined the effects of extracting metallic ions inside the soil using supercritical CO{sub 2} and catecholamine as the ligand. Based on these results, it is evident that when only the extraction agent was used, there was no extraction effect and that only when the ligand, co-ligand, and additive were used together was there an extraction effect. Following this, the optimal extraction-agent ratio was confirmed using varying amounts of extraction agents. The most effective extraction ratio of ligand to co-ligand was 1:2 in E-9 when 0.3 ml of H{sub 2}O were added.

  14. Sequential extraction of heavy metals in soils from a copper mine

    Science.gov (United States)

    Arenas, Daniel; Lago, Manoel; Vega, Flora; Andrade, Luisa

    2013-04-01

    Metal mining produces a large amount of waste materials where mine soils can be formed. They use to have important limitations for plant development like extreme pH and low organic matter among others. On metal mines they usually have problems of pollution by heavy metals (Asensio et al., 2013) generally concerning more than one metal. At Touro (Galicia, Spain) copper was mining from 1973 to 1988. Nowadays, there are soils formed on the tailings formed with waste and thick materials coming from copper extraction and on the settling pond since it is emerged and dry. They are partly exposed to weathering and the iron, copper, sulphides and H+ can be released causing acid mine drainage and heavy metal solubilization. Since heavy metals can adsorb onto the soil, runoff into rivers or lakes or leach in the groundwater (Mulligan et al., 2001) it is very important to study the soils mechanisms involved in both retention and solubility of heavy metals. The sequential extraction procedures allow to better understand them since the chosen extractions attempt to minimize solubilization of other soil fractions even none of them is completely specific (Mulligan et al., 2001). At Touro mine, five soils were sampled and analysed for those properties known as heavy metal retention determiners. The distribution of Cr, Cu, Mn, Ni, Pb and Zn among geochemical soil phases was analysed following the modified sequential extraction technique of Shuman (1979, 1985). The concentration in the extractions was analysed by ICP-OES. The results show that most of the heavy metal content is associated to the residual fraction in all soils Cr (85-92%), Cu (53-81%), Mn (80-98%), Ni (86-96%), Pb (47-81%) and Zn (85-95%). The high crystalline Fe-oxides content also plays an important role, specially for Cu (18-22% of the total Cu). The amount of heavy metals associated to soil organic matter is very low (Pb and Cu: heavy metal contents are strongly retained in low accessible soil fractions. Still

  15. Proposal of new convenient extractant for assessing phytoavailability of heavy metals in contaminated sandy soil.

    Science.gov (United States)

    Korzeniowska, Jolanta; Stanislawska-Glubiak, Ewa

    2017-06-01

    The aim of the study was to compare the usefulness of 1 M HCl with aqua regia, EDTA, and CaCl2 for the extraction of phytoavailable forms of Cu, Ni, and Zn on coarse-textured soils contaminated with these metals. Two microplot experiments were used for the studies. Reed canary grass (Phalaris arundinacea), maize (Zea mays), willow (Salix viminalis), spartina (Spartina pectinata), and miscanthus (Miscanthus × giganteus) were used as test plants. They were grown on soil artificially spiked with Cu, Ni, and Zn. The experimental design included a control and three increasing doses of metals. Microplots (1 m(2) × 1 m deep) were filled with sandy soil (clay-6%, pH 5.5, Corg-0.8%). Metals in the form of sulfates were dissolved in water and applied to the plot using a hand liquid sprayer. During the harvest, samples were collected from aboveground parts, roots, and the soil and then tested for their Cu, Zn, and Ni contents. The metal content of the soil was determined using four tested extractants. It was found that Cu and Ni were accumulated in roots in bigger amounts than Zn. The usefulness of the extractants was evaluated based on the correlation between the content of metals in the soil and the plant (n = 32). This study demonstrated that 1 M HCl, aqua regia, and EDTA were more efficient or equally useful for the assessment of the phytoavailability of Cu, Ni, and Zn as CaCl2. Due to the ease of performing determinations and their low cost, 1 M HCl can be recommended to assess the excess of Cu, Ni, and Zn in the coarse-textured soils.

  16. Effects of flow regime and flooding on heavy metal availability in sediment and soil of a dynamic river system

    NARCIS (Netherlands)

    Poot, A.; Gillissen, F.; Koelmans, A.A.

    2007-01-01

    The acid volatile sulphide (AVS) and simultaneously extracted metals (¿SEM) method is increasingly used for risk assessment of toxic metals. In this study, we assessed spatial and temporal variations of AVS and ¿SEM in river sediments and floodplain soils, addressing influence of flow regime and flo

  17. Má oclusão Classe III de Angle, subdivisão direita, tratada sem exodontias e com controle de crescimento Angle Class III malocclusion, subdivision right, treated without extractions and with growth control

    Directory of Open Access Journals (Sweden)

    Sérgio Henrique Casarim Fernandes

    2010-12-01

    Full Text Available A Classe III de Angle é uma má oclusão caracterizada por discrepâncias anteroposteriores dentárias e faciais, normalmente acompanhadas por alterações esqueléticas, com componente genético associado. O diagnóstico precoce e correto e o tratamento adequado são de suma importância para promover o controle do crescimento e evitar recidivas. Este artigo relata o tratamento, executado em duas fases, de uma paciente do sexo feminino de 12 anos de idade, apresentando uma má oclusão de Classe III de Angle, subdivisão direita, com mordida cruzada anterior em máxima intercuspidação habitual (MIH e topo em relação cêntrica (RC, apresentando, ainda, falta de espaço na maxila, que foi tratada sem exodontias e com controle de crescimento. Esse caso foi apresentado à Diretoria do Board Brasileiro de Ortodontia e Ortopedia Facial (BBO, representando a categoria 1, ou seja, uma má oclusão Classe III de Angle, tratada sem exodontias e com controle de crescimento, como parte dos requisitos para a obtenção do título de Diplomado pelo BBOAngle Class III malocclusion is characterized by anteroposterior dental and facial discrepancies usually accompanied by skeletal changes associated with a genetic component. Early, accurate diagnosis and appropriate treatment are of paramount importance to promote growth control and prevent relapse. This article reports the two-phase treatment of a female patient, aged 12 years, with an Angle Class III, subdivision right malocclusion with anterior crossbite in maximum intercuspation (MIC and end-on bite in centric relation, further presenting with lack of maxillary space. The case was treated without extractions and with growth control. This case was presented to the Brazilian Board of Orthodontics and Facial Orthopedics (BBO as representative of Category 1, i.e., Angle Class III malocclusion treated without tooth extractions, as part of the requirements for obtaining the BBO Diploma

  18. Competitive adsorption of heavy metal by extracellular polymeric substances (EPS) extracted from sulfate reducing bacteria.

    Science.gov (United States)

    Wang, Jin; Li, Qing; Li, Ming-Ming; Chen, Tian-Hu; Zhou, Yue-Fei; Yue, Zheng-Bo

    2014-07-01

    Competitive adsorption of heavy metals by extracellular polymeric substances (EPS) extracted from Desulfovibrio desulfuricans was investigated. Chemical analysis showed that different EPS compositions had different capacities for the adsorption of heavy metals which was investigated using Cu(2+) and Zn(2+). Batch adsorption tests indicated that EPS had a higher combined ability with Zn(2+) than Cu(2+). This was confirmed and explained by Fourier transform infrared (FTIR) and excitation-emission matrix (EEM) spectroscopy analysis. FTIR analysis showed that both polysaccharides and protein combined with Zn(2+) while only protein combined with Cu(2+). EEM spectra further revealed that tryptophan-like substances were the main compositions reacted with the heavy metals. Moreover, Zn(2+) had a higher fluorescence quenching ability than Cu(2+).

  19. A New Direction for Biomining: Extraction of Metals by Reductive Dissolution of Oxidized Ores

    Directory of Open Access Journals (Sweden)

    Kevin B. Hallberg

    2013-01-01

    Full Text Available Biomining, the biotechnology that uses microorganisms to extract metals from ores and concentrates, is currently used exclusively for processing reduced ores and mine wastes. Metals of economic value also occur extensively in oxidized ores, such as nickel laterites. While these are not amenable to oxidative dissolution, the ferric iron minerals they contain can, in theory, be disrupted by iron reduction, causing associated metals to be released. We have harnessed the ability of the facultatively anaerobic, acidophilic bacterium Acidithiobacillus ferroooxidans to couple the oxidation of elemental sulphur to the reduction of ferric iron in the goethite fraction of a limonitic nickel ore at 30 °C. Nickel and other metals (Co, Cr and Mn were effectively solubilised and maintained in solution due to the low pH (1.8 of the leach liquor. The results highlight the potential for the bioprocessing of oxidized, iron-rich ores using an approach that is energy-saving and environmentally-benign compared with metallurgical processes currently applied to the extraction of Ni from lateritic ores.

  20. Complex-forming organic ligands in cloud-point extraction of metal ions: a review.

    Science.gov (United States)

    Pytlakowska, K; Kozik, V; Dabioch, M

    2013-06-15

    Cloud-point extraction (CPE), an easy, safe, environmentally friendly, rapid and inexpensive methodology for preconcentration and separation of trace metals from aqueous solutions has recently become an attractive area of research and an alternative to liquid-liquid extraction. Moreover, it provides results comparable to those obtained with other separation techniques and has a greater potential to be explored in improving detection limits and other analytical characteristics over other methods. A few reviews have been published covering different aspects of the CPE procedure and its relevant applications, such as the phenomenon of clouding, the application in the extraction of trace inorganic and organic materials, as well as pesticides and protein substrates from different sources, or incorporation of CPE into an FIA system. This review focuses on general properties of the most frequently used organic ligands in cloud-point extraction and on literature data (from 2000 to 2012) concerning the use of modern techniques in determination of metal ions' content in various materials. The article is divided according to the class of organic ligands to be used in CPE.

  1. Supercritical fluid extraction and gas chromatography or electroanalysis of metal chelates from different sample matrices

    Science.gov (United States)

    Arancibia; Segura; Leiva; Contreras; Valderrama

    2000-01-01

    The supercritical fluid extraction of Pb(DDC)2 and MoO2(acac)2 complexes is performed. The previously formed complexes are used in order to simplify the extraction process. In the extraction cell, 9.0 mg of Pb(DDC)2 or 30.0 mg of MoO2(acac)2 is added. With these two complexes, a study of static and dynamic extraction as a function of pressure (1000-2500 psi), temperature (40-160 degrees C), and presence of modifier (methanol) is performed. Under the best conditions, 5.6 mg of Pb(DDC)2 (2.3 mg of Pb2+) is recovered. The parameters are 2500 psi of pressure, 160 degrees C of temperature, 0.5 mL methanol (placed in a 10-mL extraction cell), 60.0 min of static extraction, and 2.0 min of dynamic extraction. It is necessary to add 3.0 mL of methanol to enhance efficiency on the MoO2(acac)2 complex recovery. Quantitative extractions of MoO2(acac)2 (9.0 mg of MoVI) are obtained when the experiments are carried out under 1000-2500 psi of pressure, 140 degrees C, and times no longer than 10.0 min. Then, the study is carried out forming the in situ complexes. For this purpose, metallic ion and ligand are added. Under these conditions, the Pb2+ recovery decreases from 2.3 to 1.9 mg, and the MoVI recovery decreases from 9.0 to 1.0 mg. When 1.9 mg of Pb2+ and 1.0 mg of MoVI or less is placed in the extraction cell, the recoveries are always 100%. The Pb2+ extracts are directly accomplished using gas chromatography-flame ionization detection (GC-FID), and the MoVI extracts are analyzed using GC-FID and catalytic adsorption voltammetry. The quantitation of pure extracts is carried out by constructing calibration curves with complex solutions and sample solutions using the standard addition method. This method is applied by determination of Pb2+ in sodium alginate extracted from algae and blood, urine, and human milk from patients with diagnosed plumbunemy. MoVI is determined in irrigation water and pasture of animal intake.

  2. Fractionation of Heavy Metals in Fly Ash from Wood Biomass Using the BCR Sequential Extraction Procedure.

    Science.gov (United States)

    Jukić, Mirela; Ćurković, Lidija; Šabarić, Jasenka; Kerolli-Mustafa, Mihone

    2017-08-20

    The aim of this study was to extract the wood biomass fly ash fractions by a three-stage sequential extraction method for acetic acid and ion exchangeable (BCR 1), hydroxylamine hydrochloride reduction (BCR 2), and hydrogen peroxide oxidation (BCR 3) fractions in order to access the leaching behavior of this residue. The fly ash was collected as a by-product from the processing of mixed wood biomass in Udbina combustion facility, Croatia. Concentrations of several elements (As, Cd, Cr, Cu, Ni, Pb and Zn) in all extracts were determined by inductively coupled plasma atomic emission spectrometry. The acidic exchangeable form of the metals was used to evaluate the potential ecological risk of biomass fly ash. According to calculated potential ecological risk index, it is confirmed that mobility of Ni and As has major environmental impact. However the results of potential ecological risk show that biomass fly ash had a low risk.

  3. Utilizing a sequential injection system furnished with an extraction microcolumn as a novel approach for executing sequential extractions of metal species in solid samples

    DEFF Research Database (Denmark)

    Chomchoei, R.; Hansen, Elo Harald; Shiowatana, J.

    2007-01-01

    feasible, uni-directional and bi-directional flow schemes being used herein. A three-step sequential extraction scheme, using conventionally adopted extractants, was used to evaluate the system by determining Ca, Fe, Mn, Cu, Zn in a soil certified reference material (NIST, SRM 2710). It is demonstrated...... that the system entails many advantages such as being fully automated, and besides being characterised by rapidity, ease of operation and robustness, it is less prone to risks of contamination and personal errors as encountered in traditional batch systems. Moreover, improvement of the precision and accuracy...... of the chemical fractionation of metal in solids as compared with previous reports are obtained. The system ensures that extraction is performed at designated pH values. Variation of sample weight to column volume ratios do not affect the amounts of extractable metals, nor do extraction flow rates ranging from 50...

  4. Recovery of rare earths from acid leach solutions of spent nickel-metal hydride batteries using solvent extraction

    Institute of Scientific and Technical Information of China (English)

    夏允; 肖连生; 田吉英; 李兆洋; 曾理

    2015-01-01

    The extraction of rare earths from acid leach solutions of spent nickel-metal hydride batteries using a primary amine ex-tractant of N1923 was studied. The effects of feed pH, temperature, agitation rate and time on the extraction of rare earths, as well as stripping agent composition and concentration, phase ratio on the stripping were investigated. In addition, the extraction isotherm was determined. The pilot plant test results showed that the extraction of rare earths reached 99.98% after a five-stage counter current ex-traction. The mixed rare earths oxalates with the 99.77% purity of rare earth elements and impurity content less than 0.05% were ob-tained by the addition of oxalic acids in loaded strip liquors. The extractant exhibited good selectivity of rare earths over base metals of iron, nickel, copper and manganese.

  5. The ultrasound assisted extraction of matrix elements and heavy metal fractions associated with Fe, Al and Mn oxyhydroxides from soil

    Directory of Open Access Journals (Sweden)

    Stanišić Svetlana M.

    2012-01-01

    Full Text Available The single agent extractions of major and trace metals from soil sample were conducted by means of rotary mixer and ultrasonic bath with sonication time of 10, 20, 30, 40 and 50 min. The sequential extraction according to the BCR scheme was undertaken. The obtained soil extracts were analyzed by ICP-OES and according to the results the rotary mixer assisted extraction was more efficient in the case of alkaline-earth elements. However, by the use of ultrasound several times higher amounts of matrix elements (Fe, Al and Mn and heavy metals predominantly associated with Fe, Al and Mn oxyhydroxides were extracted. The increase of the sonication time failed to improve extraction yields. The changes of the conductivity, pH, oxidoreduction potential, particle size diameter and zeta potential of colloid particles, with the sonication time increase were measured. The extraction mechanism and expressed selectivity of ultrasound is discussed and explanation is suggested.

  6. Metal Extraction Processes for Electronic Waste and Existing Industrial Routes: A Review and Australian Perspective

    Directory of Open Access Journals (Sweden)

    Abdul Khaliq

    2014-02-01

    Full Text Available The useful life of electrical and electronic equipment (EEE has been shortened as a consequence of the advancement in technology and change in consumer patterns. This has resulted in the generation of large quantities of electronic waste (e-waste that needs to be managed. The handling of e-waste including combustion in incinerators, disposing in landfill or exporting overseas is no longer permitted due to environmental pollution and global legislations. Additionally, the presence of precious metals (PMs makes e-waste recycling attractive economically. In this paper, current metallurgical processes for the extraction of metals from e-waste, including existing industrial routes, are reviewed. In the first part of this paper, the definition, composition and classifications of e-wastes are described. In the second part, separation of metals from e-waste using mechanical processing, hydrometallurgical and pyrometallurgical routes are critically analyzed. Pyrometallurgical routes are comparatively economical and eco-efficient if the hazardous emissions are controlled. Currently, pyrometallurgical routes are used initially for the segregation and upgrading of PMs (gold and silver into base metals (BMs (copper, lead and nickel and followed by hydrometallurgical and electrometallurgical processing for the recovery of pure base and PMs. For the recycling of e-waste in Australia, challenges such as collection, transportation, liberation of metal fractions, and installation of integrated smelting and refining facilities are identified.

  7. Bio-processing of solid wastes and secondary resources for metal extraction - A review.

    Science.gov (United States)

    Lee, Jae-Chun; Pandey, Banshi Dhar

    2012-01-01

    Metal containing wastes/byproducts of various industries, used consumer goods, and municipal waste are potential pollutants, if not treated properly. They may also be important secondary resources if processed in eco-friendly manner for secured supply of contained metals/materials. Bio-extraction of metals from such resources with microbes such as bacteria, fungi and archaea is being increasingly explored to meet the twin objectives of resource recycling and pollution mitigation. This review focuses on the bio-processing of solid wastes/byproducts of metallurgical and manufacturing industries, chemical/petrochemical plants, electroplating and tanning units, besides sewage sludge and fly ash of municipal incinerators, electronic wastes (e-wastes/PCBs), used batteries, etc. An assessment has been made to quantify the wastes generated and its compositions, microbes used, metal leaching efficiency etc. Processing of certain effluents and wastewaters comprising of metals is also included in brief. Future directions of research are highlighted. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Characterisation of the dilute HCl extraction method for the identification of metal contamination in Antarctic marine sediments.

    Science.gov (United States)

    Snape, I; Scouller, R C; Stark, S C; Stark, J; Riddle, M J; Gore, D B

    2004-11-01

    A regional survey of potential contaminants in marine or estuarine sediments is often one of the first steps in a post-disturbance environmental impact assessment. Of the many different chemical extraction or digestion procedures that have been proposed to quantify metal contamination, partial acid extractions are probably the best overall compromise between selectivity, sensitivity, precision, cost and expediency. The extent to which measured metal concentrations relate to the anthropogenic fraction that is bioavailable is contentious, but is one of the desired outcomes of an assessment or prediction of biological impact. As part of a regional survey of metal contamination associated with Australia's past waste management activities in Antarctica, we wanted to identify an acid type and extraction protocol that would allow a reasonable definition of the anthropogenic bioavailable fraction for a large number of samples. From a kinetic study of the 1 M HCl extraction of two Certified Reference Materials (MESS-2 and PACS-2) and two Antarctic marine sediments, we concluded that a 4 h extraction time allows the equilibrium dissolution of relatively labile metal contaminants, but does not favour the extraction of natural geogenic metals. In a regional survey of 88 marine samples from the Casey Station area of East Antarctica, the 4 h extraction procedure correlated best with biological data, and most clearly identified those sediments thought to be contaminated by runoff from abandoned waste disposal sites. Most importantly the 4 h extraction provided better definition of the low to moderately contaminated locations by picking up small differences in anthropogenic metal concentrations. For the purposes of inter-regional comparison, we recommend a 4 h 1 M HCl acid extraction as a standard method for assessing metal contamination in Antarctica.

  9. Metal oxide-graphene field-effect transistor: interface trap density extraction model

    Directory of Open Access Journals (Sweden)

    Faraz Najam

    2016-09-01

    Full Text Available A simple to implement model is presented to extract interface trap density of graphene field effect transistors. The presence of interface trap states detrimentally affects the device drain current–gate voltage relationship Ids–Vgs. At the moment, there is no analytical method available to extract the interface trap distribution of metal-oxide-graphene field effect transistor (MOGFET devices. The model presented here extracts the interface trap distribution of MOGFET devices making use of available experimental capacitance–gate voltage Ctot–Vgs data and a basic set of equations used to define the device physics of MOGFET devices. The model was used to extract the interface trap distribution of 2 experimental devices. Device parameters calculated using the extracted interface trap distribution from the model, including surface potential, interface trap charge and interface trap capacitance compared very well with their respective experimental counterparts. The model enables accurate calculation of the surface potential affected by trap charge. Other models ignore the effect of trap charge and only calculate the ideal surface potential. Such ideal surface potential when used in a surface potential based drain current model will result in an inaccurate prediction of the drain current. Accurate calculation of surface potential that can later be used in drain current model is highlighted as a major advantage of the model.

  10. Phytochemicals and heavy metals analysis of methanolic extract of edible mushrooms collected from Karak District, Khyber Pakhtunkhwa, Pakistan

    Institute of Scientific and Technical Information of China (English)

    Farhan; Hameed Ur Rehman; Sajid Awais; Nisar Ahmad; Baharullah Khattak

    2016-01-01

    Objective:To qualitatively evaluate the phytochemicals and quantitatively determine the heavy metals of three species of edible mushrooms collected from the Karak area of Khyber Pukhtoonkhwa, Pakistan. Methods:The plant sample was subjected to methanolic extraction. The extraction was then concentrated by using rotary evaporator. The methanolic extract was screened for the qualitative study of various phytochemicals and quantitative measurement of heavy metals. Results: A maximum of phytochemicals were confirmed by carring out different tests. Among the different phytochemicals, alkaloids, flavonoids, proteins and carbohydrates were found to be present in the extracts, while saponins and glycosides were not detected. Similarly quantitative study of heavy metals was also conducted on the same extracts of the edible mushrooms. The results suggested that iron was present in maximum concentration than all other metals and nickel was found to be present in little amount when compared with other metals. All the metals were found present. Conclusions:The concentrations of heavy metals were investigated in the samples which were different in all samples. The presence of different phytochemicals in the mushroom is the key for its active biological profile.

  11. Phytochemicals and heavy metals analysis of methanolic extract of edible mushrooms collected from Karak District, Khyber Pakhtunkhwa, Pakistan

    Directory of Open Access Journals (Sweden)

    Farhan

    2016-09-01

    Full Text Available Objective: To qualitatively evaluate the phytochemicals and quantitatively determine the heavy metals of three species of edible mushrooms collected from the Karak area of Khyber Pukhtoonkhwa, Pakistan. Methods: The plant sample was subjected to methanolic extraction. The extraction was then concentrated by using rotary evaporator. The methanolic extract was screened for the qualitative study of various phytochemicals and quantitative measurement of heavy metals. Results: A maximum of phytochemicals were confirmed by carring out different tests. Among the different phytochemicals, alkaloids, flavonoids, proteins and carbohydrates were found to be present in the extracts, while saponins and glycosides were not detected. Similarly quantitative study of heavy metals was also conducted on the same extracts of the edible mushrooms. The results suggested that iron was present in maximum concentration than all other metals and nickel was found to be present in little amount when compared with other metals. All the metals were found present. Conclusions: The concentrations of heavy metals were investigated in the samples which were different in all samples. The presence of different phytochemicals in the mushroom is the key for its active biological profile.

  12. “High-Throughput” Evaluation of Polymer-Supported Triazolic Appendages for Metallic Cations Extraction

    Directory of Open Access Journals (Sweden)

    Riadh Slimi

    2015-03-01

    Full Text Available The aim of this work was to find and use a low-cost high-throughput method for a quick primary evaluation of several metal extraction by substituted piperazines appendages as chelatants grafted onto Merrifield polymer using click-chemistry by the copper (I-catalyzed Huisgen’s reaction (CuAAC The polymers were tested for their efficiency to remove various metal ions from neutral aqueous solutions (13 cations studied: Li+, Na+, K+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Cd2+, Ba2+, Ce3+, Hg+ and Pb2+ using the simple conductimetric measurement method. The polymers were found to extract all metals with low efficiencies ≤40%, except for Fe3+ and Hg+, and sometimes Pb2+. Some polymers exhibited a selectively for K+, Cd2+ and Ba2+, with good efficiencies. The values obtained here using less polymer, and a faster method, are in fair correspondence (average difference ±16% with another published evaluation by atomic absorption spectroscopy (AAS.

  13. Dynamics of a Rydberg hydrogen atom near a metal surface in the electron-extraction scheme

    Energy Technology Data Exchange (ETDEWEB)

    Iñarrea, Manuel [Área de Física Aplicada, Universidad de La Rioja, Logroño (Spain); Lanchares, Víctor [Departamento de Matemáticas y Computación, Universidad de La Rioja, Logroño, La Rioja (Spain); Palacián, Jesús [Departamento de Ingeniería Matemática e Informática, Universidad Pública de Navarra, Pamplona (Spain); Pascual, Ana I. [Departamento de Matemáticas y Computación, Universidad de La Rioja, Logroño, La Rioja (Spain); Salas, J. Pablo, E-mail: josepablo.salas@unirioja.es [Área de Física Aplicada, Universidad de La Rioja, Logroño (Spain); Yanguas, Patricia [Departamento de Ingeniería Matemática e Informática, Universidad Pública de Navarra, Pamplona (Spain)

    2015-01-23

    We study the classical dynamics of a Rydberg hydrogen atom near a metal surface in the presence of a constant electric field in the electron-extraction situation [1], e.g., when the field attracts the electron to the vacuum. From a dynamical point of view, this field configuration provides a dynamics richer than in the usual ion-extraction scheme, because, depending on the values of field and the atom–surface distance, the atom can be ionized only towards the metal surface, only to the vacuum or to the both sides. The evolution of the phase space structure as a function of the atom–surface distance is explored in the bound regime of the atom. In the high energy regime, the ionization mechanism is also investigated. We find that the classical results of this work are in good agreement with the results obtained in the wave-packet propagation study carried out by So et al. [1]. - Highlights: • We study a classical hydrogen atom near a metal surface plus a electric field. • We explore the phase space structure as a function of the field strength. • We find most of the electronic orbits are oriented along the field direction. • We study the ionization of the atom for several atom–surface distances. • This classical study is in good agreement with the quantum results.

  14. Extraction procedure testing of solid wastes generated at selected metal ore mines and mills

    Science.gov (United States)

    Harty, David M.; Terlecky, P. Michael

    1986-09-01

    Solid waste samples from a reconnaissance study conducted at ore mining and milling sites were subjected to the U.S. Environmental Protection Agency extraction procedure (EP) leaching test Sites visited included mines and mills extracting ores of antimony (Sb), mercury (Hg), vanadium (V), tungsten (W), and nickel (Ni). Samples analyzed included mine wastes, treatment pond solids, tailings, low grade ore, and other solid wastes generated at these facilities Analysis of the leachate from these tests indicates that none of the samples generated leachate in which the concentration of any toxic metal parameter exceeded EPA criteria levels for those metals. By volume, tailings generally constitute the largest amount of solid wastes generated, but these data indicate that with proper management and monitoring, current EPA criteria can be met for tailings and for most solid wastes associated with mining and milling of these metal ores. Long-term studies are needed to determine if leachate characteristics change with time and to assist in development of closure plans and post closure monitoring programs.

  15. Rice straw modified by click reaction for selective extraction of noble metal ions.

    Science.gov (United States)

    Wang, Jingjing; Wei, Jun; Li, Juan

    2015-02-01

    Rice straw was modified by azide-alkyne click reaction in order to realize selective extraction of noble metal ions. The ability of the modified straw to adsorb Pd(2+) and Pt(4+) was assessed using a batch adsorption technique. It was found that the sorption equilibrium could be reached within 1h and the adsorption capacity increased with temperature for both Pd(2+) and Pt(4+). The maximum sorption capacities for Pd(2+) and Pt(4+) were respectively attained in 1.0 and 0.1 mol/L HCl. The modified straw showed excellent selectivity for noble metal ions in comparison to the pristine straw. In addition, the modified straw was examined as a column packing material for extraction of noble metal ions. It was indicated that 1.0 mL/min was the best flow rate for Pd(2+) and Pt(4+). The modified straw could be repeatedly used for 10 times without any significant loss in the initial binding affinity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Sequential Extraction of Natural Surface Coatings: Comparison with Single Stage Extraction and Its Application in Investigating Adsorption Characteristics of Surface Coating Components for Metals

    Institute of Scientific and Technical Information of China (English)

    HUA Xiu-yi; LIU Xiao-xue; DONG De-ming; LI Ming; LI Yao-rui

    2012-01-01

    Multistage sequential extraction with different sequences was applied to extracting natural surface coatings(NSCs),and the results were compared with those by single stage extraction technique.The optimal sequential extraction scheme with the best performance was selected and incorporated into the method of selective extraction followed by adsorption and statistic analyses to study the adsorption parameters of Fe oxides,Mn oxides and organic matters in NSCs for Pb and Cd,to validate the applicability of the sequential extraction scheme.The Langmuir adsorption parameters of each component of surface coating estimated according to the adsorption data of single stage extraction of NSCs were all similar to those of sequential extraction of NSCs,and the maximum difference between the metal adsorption abilities of the components estimated via the two extraction techniques was only about 20%,indicating that either extraction techniques could be used.The optimal sequential extraction scheme obtained was first extracted with NH2OH·HCl,then with Na2S2O4,and finally with oxalic acid.

  17. Temperature responsive hydrogel magnetic nanocomposites for hyperthermia and metal extraction applications

    Science.gov (United States)

    Reddy, N. Narayana; Ravindra, S.; Reddy, N. Madhava; Rajinikanth, V.; Raju, K. Mohana; Vallabhapurapu, Vijaya Srinivasu

    2015-11-01

    The present work deals with the development of temperature and magnetic responsive hydrogel networks based on poly (N-isopropylacrylamide)/acrylamido propane sulfonic acid. The hydrogel matrices are synthesized by polymerizing N-isopropylacrylamide (NIPAM) monomer in the presence of acrylamido propane sulphonicacid (AMPS) using a cross-linker (N,N-methylenebisacrylamide, MBA) and redox initiating system [ammonium persulphate (APS)/tetramethylethylenediamine (TMEDA)]. The magnetic nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating iron ions and subsequent treatment with ammonia. A series of hydrogel-magnetic nanocomposites (HGMNC) are developed by varying AMPS composition. The synthesized hydrogel magnetic nanocomposites (HGMNC) are characterized by using Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), Thermal Analyses and Electron Microscopy analysis (Scanning and Transmission Electron Microscope). The metal extraction capacities of the prepared hydrogel (HG) and hydrogel magnetic nanocomposites (HGMNC) were studied at different temperatures. The results suggest that HGMNCs have higher extraction capacity compared to HG and HG loaded iron ions. This data also reveals that the extraction of metals by hydrogel magnetic nanocomposites (HGMNCs) is higher at higher temperatures than room temperature. The prepared HGMNCs are also subjected to hyperthermia (cancer therapy) studies.

  18. Remediation of heavy-metal-contaminated soil using chelant extraction: Feasibility studies

    Energy Technology Data Exchange (ETDEWEB)

    Peters, R.W.; Miller, G.; Taylor, J.D.; Schneider, J.F.; Zellmer, S.; Edgar, D.E.; Johnson, D.O.

    1993-08-01

    Results are presented of a laboratory investigation conducted to determine the efficacy of using chelating agents to extract heavy metals (Pb, Cd, Cr, Ba, Cu, and Zn) from soil, the primary focus being on the extraction of lead from the soil. Results from the batch-shaker studies and emphasizes the columnar extraction studies are described. The chelating agents studied included ethylenediaminetetraacetic acid (EDTA) and citric acid, in addition to water. Concentrations of the chelants ranged from 0.01 to 0.05 M; the suspension pH was varied between 3 and 8. Results showed that the removal of lead using citric acid and water was somewhat pH-dependent. For the batch-shaker studies, the results indicated that EDTA was more effective at removing Cd, Cu, Pb, and Zn than was citric acid (both present at 0.01 M). EDTA and citric acid were equally effective in mobilizing Cr and Ba from the soil. Heavy metals removal was slightly more effective in the more acidic region (pH {le} 5).

  19. Biogenic Synthesis of Metal Nanoparticles Using a Biosurfactant Extracted from Corn and Their Antimicrobial Properties

    Directory of Open Access Journals (Sweden)

    Sergio Gómez-Graña

    2017-06-01

    Full Text Available A new and promising biosurfactant extracted from corn steep liquor has been used for the green synthesis of gold and silver nanoparticles (NPs in a one-step procedure induced by temperature. Most of the biosurfactants proposed in the literature are produced by pathogenic microorganisms; whereas the biosurfactant used in the current work was extracted from a liquid stream, fermented spontaneously by lactic acid bacteria, which are “generally recognized as safe” (GRAS microorganisms. The reduction of a gold precursor in the presence of a biosurfactant gives rise to a mixture of nanospheres and nanoplates with distinct optical features. Moreover, the growth of nanoplates can be promoted by increasing the reaction temperature to 60 °C. In the case of silver, the biosurfactant just induces the formation of pseudo-spherical NPs. The biosurfactant plays a key role in the reduction of the metal precursor, as well as in the stabilization of the resulting NPs. Furthermore, the antimicrobial activity of the resulting silver colloids has been analyzed against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The biosurfactant stabilized NPs slightly increased the inhibition of E. coli in comparison with citrate stabilized Ag NPs. The use of this biosurfactant extracted from corn steep liquor for the synthesis of metal NPs contributes to enhancing the application of green technologies and increasing the utilization of clean, non-toxic and environmentally safe production processes. Therefore, it can help to reduce environmental impact, minimize waste and increase energy efficiency in the field of nanomaterials.

  20. Mathematical modeling of cadmium(II) solvent extraction from neutral and acidic chloride media using Cyanex 923 extractant as a metal carrier.

    Science.gov (United States)

    Leopold, A A; Coll, M T; Fortuny, A; Rathore, N S; Sastre, A M

    2010-10-15

    This paper describes experimental work and the mathematical modeling of solvent extraction of cadmium(II) from neutral and acidic aqueous chloride media with a Cyanex 923 extractant in Exxol D-100. Solvent extraction experiments were carried out to analyze the influence of variations in the composition of the aqueous and organic phases on the efficiency of cadmium(II) extraction. In neutral and acidic chloride conditions, the extraction of cadmium(II) by the organophosphorous extractant Cyanex 923 (L) is based on the solvation mechanism of neutral H(n)CdCl((2+n)) species and the formation of H(n)CdCl((2+n))L(q) complexes in the organic phase, where n=0, 1, 2 and q=1, 2. The mathematical model of cadmium(II) extraction was derived from the mass balances and chemical equilibria involved in the separation system. The model was computed with the Matlab software. The equilibrium parameters for metal extraction, i.e. the stability constants of the aqueous Cd-Cl complexes, the formation constants of the acidic Cd-Cl species and the metal equilibrium extraction constants, were proposed. The optimized constants were appropriate, as there was good agreement when the model was fitted to the experimental data for each of the experiments.

  1. Mathematical modeling of cadmium(II) solvent extraction from neutral and acidic chloride media using Cyanex 923 extractant as a metal carrier

    Energy Technology Data Exchange (ETDEWEB)

    Leopold, A.A., E-mail: agnieszka.leopold@upc.edu [Department of Chemical Engineering, Universitat Politecnica de Catalunya, EPSEVG, Av. Victor Balaguer s/n, 08800 Vilanova i la Geltru (Spain); Coll, M.T.; Fortuny, A.; Rathore, N.S. [Department of Chemical Engineering, Universitat Politecnica de Catalunya, EPSEVG, Av. Victor Balaguer s/n, 08800 Vilanova i la Geltru (Spain); Sastre, A.M. [Department of Chemical Engineering, Universitat Politecnica de Catalunya, ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain)

    2010-10-15

    This paper describes experimental work and the mathematical modeling of solvent extraction of cadmium(II) from neutral and acidic aqueous chloride media with a Cyanex 923 extractant in Exxol D-100. Solvent extraction experiments were carried out to analyze the influence of variations in the composition of the aqueous and organic phases on the efficiency of cadmium(II) extraction. In neutral and acidic chloride conditions, the extraction of cadmium(II) by the organophosphorous extractant Cyanex 923 (L) is based on the solvation mechanism of neutral H{sub n}CdCl{sub (2+n)} species and the formation of H{sub n}CdCl{sub (2+n)}L{sub q} complexes in the organic phase, where n = 0, 1, 2 and q = 1, 2. The mathematical model of cadmium(II) extraction was derived from the mass balances and chemical equilibria involved in the separation system. The model was computed with the Matlab software. The equilibrium parameters for metal extraction, i.e. the stability constants of the aqueous Cd-Cl complexes, the formation constants of the acidic Cd-Cl species and the metal equilibrium extraction constants, were proposed. The optimized constants were appropriate, as there was good agreement when the model was fitted to the experimental data for each of the experiments.

  2. Effects of extraction procedures on metal binding properties of extracellular polymeric substances (EPS) from anaerobic granular sludges

    NARCIS (Netherlands)

    Abzac, D' P.; Bordas, F.; Hullebusch, E.; Lens, P.N.L.; Guibaud, G.

    2010-01-01

    The effects of the extraction procedure of extracellular polymeric substances (EPS) on their proton/metal binding properties were studied. Nine extraction procedures (one control, four physical and four chemical procedures) were applied to four types of anaerobic granular sludges. The binding capaci

  3. Sequential extraction of anaerobic digestate sludge for the determination of partitioning of heavy metals.

    Science.gov (United States)

    Zhu, Neng-min; Qiang-Li; Guo, Xu-jing; Hui-Zhang; Yu-Deng

    2014-04-01

    In China, agricultural use of anaerobic digestate sludge is considered a concern due to high heavy metal content of the sludge. In this study, sequential extraction procedure (SEP) was conducted to determine metal speciation which affects release and mobility of metal significantly. The results of SEP showed that each heavy metal possessed different distribution characteristics. Cu mainly reacted with carboxyl functional group to form the fraction bound to organic matter. Zn and Mn were dominated in the fraction bound to Fe-Mn oxides and carbonates, respectively. Pb, Ni, Cr, Cd and As were present as the residual fraction. Examination of mobility factors (MFs) indicated that Zn, Pb, Ni, Mn and Cd were more mobile whereas Cr and As were immobilized in anaerobic digestate. Based on the results, it can be stated that Cu, Zn, Mn, Ni and Cd may be grouped as toxic and active components in sludge and should be regarded as the priority pollutants for elimination. Pb should be monitored in terms of its high mobility factors (MF). Cr and As, nevertheless, were the most stable components in sludge. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Extraction of alginate biopolymer present in marine alga sargassum filipendula and bioadsorption of metallic ions

    Directory of Open Access Journals (Sweden)

    Sirlei Jaiana Kleinübing

    2013-04-01

    Full Text Available This paper studies the bioadsorption of Pb2+, Cu2+, Cd2+ and Zn2+ ions by marine alga Sargassum filipendula and by the alginate biopolymer extracted from this alga. The objective is to evaluate the importance of this biopolymer in removing different metallic ions by the marine alga S. filipendula. In the equilibrium study, the same affinity order was observed for both bioadsorbents: Pb2+ > Cu2+ > Zn2+ > Cd2+. For Pb2+ and Cu2+ ions when the alginate is isolated and acting as bioadsorbents, adsorption capacities greater than those found for the alga were observed, indicating that it is the main component responsible for the removal of metallic ions. For Zn2+ and Cd2+ ions, greater bioadsorption capacities were observed for the alga, indicating that other functional groups of the alga, such as sulfates and amino, are also important in the bioadsorption of these ions.

  5. Electromembrane extraction of heavy metal cations followed by capillary electrophoresis with capacitively coupled contactless conductivity detection.

    Science.gov (United States)

    Kubáň, Pavel; Strieglerová, Lenka; Gebauer, Petr; Boček, Petr

    2011-04-01

    Electromembrane extraction (EME) was used as an off-line sample pre-treatment method for the determination of heavy metal cations in aqueous samples using CE with capacitively coupled contactless conductivity detection (CE-C(4) D). A short segment of porous polypropylene hollow fibre was penetrated with 1-octanol and 0.5% v/v bis(2-ethylhexyl)phosphonic acid and constituted a low cost, single use, disposable supported liquid membrane, which selectively transported and pre-concentrated heavy metal cations into the fibre lumen filled with 100 mM acetic acid acceptor solution. Donor solutions were standard solutions and real samples dissolved in deionized water at neutral pH. At optimized EME conditions (penetration time, 5 s; applied voltage, 75 V; and stirring rate, 750 rpm), 15-42% recoveries of heavy metal cations were achieved for a 5 min extraction time. Repeatability of the EME pre-treatment was examined for six independent EME runs and ranged from 6.6 to 11.1%. Limits of detection for the EME-CE-C(4) D method ranged from 25 to 200 nM, resulting into one to two orders of magnitude improvement compared with CE-C(4) D without sample treatment. The developed EME sample pre-treatment procedure was applied to the analysis of heavy metal cations in tap water and powdered milk samples. Zinc in the real samples was identified and quantified in a background electrolyte solution consisting of 20 mM L-histidine and 30 mM acetic acid at pH 4.95 in about 3 min.

  6. Extraction of alginate biopolymer present in marine alga sargassum filipendula and bioadsorption of metallic ions

    OpenAIRE

    Sirlei Jaiana Kleinübing; Frederico Gai; Caroline Bertagnolli; Meuris Gurgel Carlos da Silva

    2013-01-01

    This paper studies the bioadsorption of Pb2+, Cu2+, Cd2+ and Zn2+ ions by marine alga Sargassum filipendula and by the alginate biopolymer extracted from this alga. The objective is to evaluate the importance of this biopolymer in removing different metallic ions by the marine alga S. filipendula. In the equilibrium study, the same affinity order was observed for both bioadsorbents: Pb2+ > Cu2+ > Zn2+ > Cd2+. For Pb2+ and Cu2+ ions when the alginate is isolated and acting as bioadsorbents, ad...

  7. Fluorous-assisted metal chelate affinity extraction technique for analysis of protein kinase activity.

    Science.gov (United States)

    Hayama, Tadashi; Kiyokawa, Ena; Yoshida, Hideyuki; Imakyure, Osamu; Yamaguchi, Masatoshi; Nohta, Hitoshi

    2016-08-15

    We have developed a fluorous affinity-based extraction method for measurement of protein kinase activity. In this method, a fluorescent peptide substrate was phosphorylated by a protein kinase, and the obtained phosphopeptide was selectively captured with Fe(III)-immobilized perfluoroalkyliminodiacetic acid reagent via a metal chelate affinity technique. Next, the captured phosphopeptide was selectively extracted into a fluorous solvent mixture, tetradecafluorohexane and 1H,1H,2H,2H-tridecafluoro-1-n-octanol (3:1, v/v), using the specificity of fluorous affinity (fluorophilicity). In contrast, the remained substrate peptide in the aqueous (non-fluorous) phase was easily measured fluorimetrically. Finally, the enzyme activity could be assayed by measuring the decrease in fluorescence. The feasibility of this method was demonstrated by applying the method for measurement of the activity of cAMP-dependent protein kinase (PKA) using its substrate peptide (kemptide) pre-labeled with carboxytetramethylrhodamine (TAMRA).

  8. Extraction equilibria of various metal picrates with 19-crown-6 between benzene and water. Effect of the extra methylene group on extraction ability and selectivity.

    Science.gov (United States)

    Katsuta, S; Kanazawa, M; Takeda, Y; Ouchi, M

    1999-07-12

    The overall extraction equilibrium constants (K(ex)) of picrates of Li(+), Na(+), K(+), Rb(+), Cs(+), Ag(+), Tl(+), and Sr(2+)with 19-crown-6 (19C6) were determined between benzene and water at 25 degrees C. The K(ex) values were analyzed into the constituent equilibrium constants, i.e. the extraction constant of picric acid, the distribution constant of the crown ether, the formation constant of the metal ion-crown ether complex in water, and the ion-pair extraction constant of the complex cation with the picrate anion. The effects of an extra methylene group of 19C6 on the extraction ability and selectivity are discussed in detail by comparing the constituent equilibrium constants of 19C6 with those of 18-crown-6 (18C6). The K(ex) value of 19C6 for each metal ion is lower than that of 18C6, which is mostly attributed to the higher lipophilicity of 19C6. The extraction ability of 19C6 for the univalent metal ions decreases in the order Tl(+)>K(+)>Rb(+)>Ag(+)>Cs(+)>Na(+)Li(+), which is the same as that observed for 18C6. The difference in logK(ex) between the univalent metals is generally smaller for 19C6 than for 18C6. The extraction selectivity of 19C6 is governed by the selectivity in the ion-pair extraction, whereas that of 18C6 depends on both the selectivities in the ion-pair extraction and in the complexation in water.

  9. Má oclusão Classe II de Angle tratada sem extrações e com controle de crescimento Angle Class II malocclusion treated without extractions and with growth control

    Directory of Open Access Journals (Sweden)

    Flávia Artese

    2009-06-01

    Full Text Available A má oclusão Classe II de Angle é caracterizada por uma discrepância dentária anteroposterior, que geralmente está acompanhada por alterações esqueléticas. O tratamento ortodôntico precoce permite a correção da discrepância esquelética por controle de crescimento (primeira fase, o que favorece a correção do posicionamento dentário, mais tardiamente (segunda fase. Este relato descreve o tratamento de um caso de má oclusão Classe II, divisão 2, de Angle, em duas fases, e foi apresentado à Diretoria do Board Brasileiro de Ortodontia e Ortopedia Facial (BBO, como parte dos requisitos para a obtenção do título de Diplomado pelo BBO. O caso foi avaliado como representante da Categoria 1, ou seja, má oclusão Classe II de Angle tratada sem extrações dentárias e com controle de crescimento.Angle Class II malocclusion is characterized by an anteroposterior dental discrepancy which is generally accompanied by skeletal disharmonies. Early orthodontic treatment allows the correction of skeletal discrepancies using growth control (first phase which favors later correction of tooth positioning (second phase. This case report describes an Angle Class II, division 2, malocclusion treated in two phases and was presented to the Brazilian Board of Orthodontics and Facial Orthopedics (BBO as part of the requirements for BBO certification. It was evaluated as a Category 1 case, i.e., Class II malocclusion treated without extractions, with growth control.

  10. Asparagus cochinchinensis Extract Alleviates Metal Ion-Induced Gut Injury in Drosophila: An In Silico Analysis of Potential Active Constituents

    Directory of Open Access Journals (Sweden)

    Weiyu Zhang

    2016-01-01

    Full Text Available Metal ions and sulfate are components of atmospheric pollutants that have diverse ways of entering the human body. We used Drosophila as a model to investigate the effect of Asparagus cochinchinensis (A. cochinchinensis extracts on the gut and characterized gut homeostasis following the ingestion of metal ions (copper, zinc, and aluminum. In this study, we found that the aqueous A. cochinchinensis extract increased the survival rate, decreased epithelial cell death, and attenuated metal ion-induced gut morphological changes in flies following chronic exposure to metal ions. In addition, we screened out, by network pharmacology, six natural products (NPs that could serve as putative active components of A. cochinchinensis that prevented gut injury. Altogether, the results of our study provide evidence that A. cochinchinensis might be an effective phytomedicine for the treatment of metal ion-induced gut injury.

  11. Cyclohexylamine as extraction solvent and chelating agent in extraction and preconcentration of some heavy metals in aqueous samples based on heat-induced homogeneous liquid-liquid extraction.

    Science.gov (United States)

    Sorouraddin, Saeed Mohammad; Farajzadeh, Mir Ali; Okhravi, Tohid

    2017-12-01

    A new sample preparation method has been developed for extraction and preconcentration of some heavy metal cations in aqueous samples using cyclohexylamine-based homogeneous liquid-liquid microextraction. In the proposed method, cyclohexylamine was used as both the complexing agent and the extraction solvent. For this purpose, cyclohexylamine at µL level was initially added into an aqueous solution containing Co(II), Ni(II), and Cu(II) ions which was placed in a glass test tube. The mixture was shaken for forming a homogeneous solution. Then sodium chloride was added to the solution. After shaking manually again, the test tube was placed in a water bath thermostated at 70°C. Due to lower solubility of cyclohexylamine at the elevated temperature, a cloudy solution was formed. The fine droplets of cyclohexylamine containing cation-cyclohexylamine complexes were collected on the top of the aqueous phase by centrifuging. The enriched analytes in the upper phase were determined by graphite furnace atomic absorption spectrometry. Several variables possibly affecting the extraction efficiency were investigated and optimized. Under the optimum conditions the calibration curves were linear in the ranges of 80-1000, 40-700, and 80-800ngL(-1) for Co(2+), Ni(2+), and Cu(2+), respectively. Repeatability of the proposed method, expressed as relative standard deviation, ranged from 3.3% to 5.2% (n = 6, C = 200ngL(-1)). Moreover, the obtained detection limits of the selected analytes were in the range of 15.3-37.7ngL(-1). The accuracy of the developed procedure was verified by analyzing a certified reference material, namely NRCC-SLRS4 Riverine water. Finally, the proposed method was successfully applied for the simultaneous analysis of the selected analytes in environmental water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Connecting SEM Analysis and Profile Analysis via MDS.

    Science.gov (United States)

    Kim, Se-Kang; Davison, Mark L.

    This study was designed to explain how Profile Analysis via Multidimensional Scaling (PAMS) could be viewed as a structural equations model (SEM). The study replicated the major profiles extracted from PAMS in the context of the latent variables in SEM. Data involved the Basic Theme Scales of the Strong Campbell Interest Inventory (Campbell and…

  13. Analytical evaluation of a cup-horn sonoreactor used for ultrasound-assisted extraction of trace metals from troublesome matrices

    Science.gov (United States)

    De La Calle, Inmaculada; Cabaleiro, Noelia; Lavilla, Isela; Bendicho, Carlos

    2009-09-01

    In this work, a sample preparation method based on ultrasound-assisted extraction of trace metals from a variety of biological and environmental matrices using a cup-horn sonoreactor is described. Diluted acids (HNO 3, HCl and HF) and oxidants (H 2O 2) were tried for extraction, the extracts being directly analyzed by electrothermal-atomic absorption spectrometry. The cup-horn sonoreactor combines the advantages of probe and bath sonicators, allowing a variety of conditions to be used for metal extraction from troublesome matrices. This system facilitates the use of HF to destroy the silicate lattice, application of simultaneous treatments of up to six samples and short treatment times. Quantitative metal recoveries are achieved from different matrices (animal and vegetal tissues, soil, sediment, fly ash, sewage sludge) under a set of extraction conditions ranging from the use of 3 min sonication time and 3% volume/volume HNO 3 for some animal tissues to 40 min sonication time along with 5% volume/volume HNO 3 + 20% volume/volume HF for sediment. Vegetal matter required the use of 5% volume/volume HNO 3 + 5% volume/volume HF for extraction of some elements. Ultrasound-assisted extraction of Cd, Mn, Pb, Ni and Cr from 16 certified reference materials representing a variety of biological and environmental matrices using the cup-horn sonoreactor is evaluated. Cd, Pb and Mn are more easily extracted from most certified reference materials (CRMs) than Cr and Ni and less stringent conditions can be chosen for the former metals. Metal extractability follows the order of difficulty: animal tissue sludge < sediment.

  14. Removal of heavy metals and arsenic from contaminated soils using bioremediation and chelant extraction techniques.

    Science.gov (United States)

    Vaxevanidou, Katerina; Papassiopi, Nymphodora; Paspaliaris, Ioannis

    2008-02-01

    A combined chemical and biological treatment scheme was evaluated in this study aiming at obtaining the simultaneous removal of metalloid arsenic and cationic heavy metals from contaminated soils. The treatment involved the use of the iron reducing microorganism Desulfuromonas palmitatis, whose activity was combined with the chelating strength of EDTA. Taking into consideration that soil iron oxides are the main scavengers of As, treatment with iron reducing microorganisms aimed at inducing the reductive dissolution of soil oxides and thus obtaining the release of the retained As. The main objective of using EDTA was the removal of metal contaminants, such as Pb and Zn, through the formation of soluble metal chelates. Experimental results however indicated that EDTA was also indispensable for the biological reduction of Fe(III) oxides. The bacterial activity was found to have a pronounced positive effect on the removal of arsenic, which increased from the value of 35% obtained during the pure chemical treatment up to 90% in the presence of D. palmitatis. In the case of Pb, the major part, i.e. approximately 85%, was removed from soil with purely chemical mechanisms, whereas the biological activity slightly improved the extraction, increasing the final removal up to 90%. Co-treatment had negative effect only for Zn, whose removal was reduced from 80% under abiotic condition to approximately 50% in the presence of bacteria.

  15. Extraction of metals from spent hydrotreating catalysts: physico-mechanical pre-treatments and leaching stage.

    Science.gov (United States)

    Ferella, Francesco; Ognyanova, Albena; De Michelis, Ida; Taglieri, Giuliana; Vegliò, Francesco

    2011-08-15

    The present paper is focused on physico-mechanical pre-treatments of spent hydrotreating catalysts aimed at concentration of at least one of the valuable metals contained in such secondary raw material. In particular, dry Ni-Mo and Co-Mo as well as wet Ni-Mo catalysts were used. Flotation, grain size separation and attrition processes were tested. After that, a rods vibrating mill and a ball mill were used to ground the catalysts in order to understand the best mechanical pre-treatment before leaching extraction. The results showed that flotation is not able to concentrate any metals due to the presence of coke or other depressant compounds. The particle size separation produces two fractions enriched in Mo and Co when dry Co-Mo catalyst is used, whereas attrition is not suitable as metals are uniformely distributed in rings' volume. Roasting at 550°C and vibrating grinding are the most suitable pre-treatments able to produce fractions easily leached by NaOH and H(2)SO(4) after grain size separation.

  16. Temperature responsive hydrogel magnetic nanocomposites for hyperthermia and metal extraction applications

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, N. Narayana, E-mail: nagireddynarayana@gmail.com [Center for Advanced Biomaterials for Healthcare, Istituto Italiano di Tecnologia@CRIB, Largo Barsanti e Matteucci 53, 80125 Napoli (Italy); Ravindra, S. [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709 (South Africa); Reddy, N. Madhava [Department of Environmental Science, Gates Institute of Technology, NH-7, Gooty, Anantapuram, Andhra Pradesh (India); Rajinikanth, V. [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709 (South Africa); Raju, K. Mohana [Synthetic Polymer Laboratory, Department of Polymer Science & Technology, S.K. University, Anantapuram, Andhra Pradesh (India); Vallabhapurapu, Vijaya Srinivasu [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709 (South Africa)

    2015-11-15

    The present work deals with the development of temperature and magnetic responsive hydrogel networks based on poly (N-isopropylacrylamide)/acrylamido propane sulfonic acid. The hydrogel matrices are synthesized by polymerizing N-isopropylacrylamide (NIPAM) monomer in the presence of acrylamido propane sulphonicacid (AMPS) using a cross-linker (N,N-methylenebisacrylamide, MBA) and redox initiating system [ammonium persulphate (APS)/tetramethylethylenediamine (TMEDA)]. The magnetic nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating iron ions and subsequent treatment with ammonia. A series of hydrogel-magnetic nanocomposites (HGMNC) are developed by varying AMPS composition. The synthesized hydrogel magnetic nanocomposites (HGMNC) are characterized by using Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), Thermal Analyses and Electron Microscopy analysis (Scanning and Transmission Electron Microscope). The metal extraction capacities of the prepared hydrogel (HG) and hydrogel magnetic nanocomposites (HGMNC) were studied at different temperatures. The results suggest that HGMNCs have higher extraction capacity compared to HG and HG loaded iron ions. This data also reveals that the extraction of metals by hydrogel magnetic nanocomposites (HGMNCs) is higher at higher temperatures than room temperature. The prepared HGMNCs are also subjected to hyperthermia (cancer therapy) studies. - Highlights: • We have developed temperature responsive hydrogel magnetic nanocomposites. • Addition of AMPS monomer to this magnetic hydrogel enhances the temperature sensitivity to 40–43 °C. • Similarly the sulfonic groups present in the AMPS units enhances the swelling ratio of magnetic hydrogels. • AMPS acts as good stabilizing agent for nanoparticles in the magnetic nanogel.

  17. Comparison of leaching characteristics of heavy metals in APC residue from an MSW incinerator using various extraction methods.

    Science.gov (United States)

    Chiang, Kung-Yuh; Tsai, Chen-Chiu; Wang, Kuen-Sheng

    2009-01-01

    This study investigates four extraction methods (water extraction, toxicity characteristics leaching procedure (TCLP), modified TCLP with pH control, and sequential chemical extraction (SCE)), each representing different liquid-to-solid (L/S) ratios, pH controls, and types of leachant, and their effects on the leaching concentration of heavy metals in municipal solid waste (MSW) incinerator air pollution control (APC) residue. The results indicated that for extraction with distilled water, the heavy metal leaching concentration (mg/l) decreased with L/S ratio, but the amount of heavy metal released (AHMR), defined as the leached amount of heavy metals to the weight of the tested sample (mg/kg), increased with an increase in L/S ratio, in the range of 2-100. The results also showed that both the leaching concentration and the amount of released metals were strongly pH-dependent in the TCLP and modified TCLP tests. In the case of pHs lower than 6.5, the leaching concentrations of Cd, Pb, Cu, Zn, and Cr decreased with an increase in pH. As pH increased higher than 6.5, Cr and Zn were almost insoluble. Meanwhile, Cd and Cu also showed a similar trend but at pHs of 8.5 and 7.5, respectively. Due to the nature of amphoteric elements, in the case of pHs higher than 7, the Pb leaching concentration increased with increasing pH. In modified TCLP tests with the pH value controlled at the same level as in the SCE test, the heavy metal speciation approached the extractable carbonate bound fraction by the SCE. Both amounts of targeted metals leached from the SCE and modified TCLP tests were much higher than those for the regular TCLP and water extraction tests.

  18. Extraction of metals from automotive shredder residue:Preliminary results of different leaching systems

    Institute of Scientific and Technical Information of China (English)

    Francesco Ferella; Ida De Michelis; Agostino Scocchera; Mario Pelino; Francesco Vegliò

    2015-01-01

    The study is focused on the extraction of valuable metals from automotive shredder residue (ASR) by different leaching solutions. First, ASR samples were roasted at 600 °C to simulate a thermal treatment processing. Distil ed water, citric and sulphuric acid were preliminarily investigated, thus two further full factorial systems entailing H2SO4–H2O2 and H2SO4–H2O2–Fe3+ were tested. The preliminary experimental results showed that 0.1 mol·L−1 H2SO4 solution extracted 100%of Cu, Fe and Zn, whereas citric acid leached 100%of Zn and Pb, 59%of Fe and 62%of Cu;whereas, H2SO4–H2O2 and H2SO4–H2O2–Fe3+(Fenton's) leaching media showed that Cu, Fe and Zn can be extracted simultaneously and completely from the ASR ashes before final disposal.

  19. Má oclusão Classe II de Angle tratada sem extrações e com controle de crescimento Angle's Class II malocclusion treated without extractions and with growth control

    Directory of Open Access Journals (Sweden)

    Maria Tereza Scardua

    2011-04-01

    Full Text Available A má oclusão Classe II de Angle é definida pela relação anteroposterior dos molares, que pode estar acompanhada por um degrau aumentado entre as bases ósseas. Estão incluídos nesse padrão os portadores de protrusão maxilar e/ou deficiência mandibular. O tratamento ortodôntico precoce permite intervenção na direção de crescimento, tanto nas bases ósseas quanto na região dentoalveolar, o que favorece a correção do posicionamento dentário na fase corretiva. O presente relato descreve o tratamento de um caso de má oclusão Classe II, divisão 1, de Angle, que foi apresentado à Diretoria do Board Brasileiro de Ortodontia e Ortopedia Facial (BBO como parte dos requisitos para a obtenção do título de Diplomado pelo BBO. O caso foi avaliado como representante da Categoria 1, ou seja, má oclusão Classe II de Angle tratada sem extrações dentárias e com controle de crescimento.Angle's Class II malocclusion is defined according to the anteroposterior molar relationship with or without a discrepancy between basal bones. Maxillary protrusion and mandibular retrusion are included in this class. When orthodontic treatment starts at an early age, it is possible to affect growth of both basal bones and the dentoalveolar region, which helps to correct tooth positioning in the corrective phase. This report describes the treatment of a case of Angle Class II, division 1 malocclusion that was presented to the Committee of the Brazilian Board of Orthodontics and Facial Orthopedics (BBO as partial fulfillment of the requirements to obtain the BBO Diploma. The case was representative of category 1, that is, Angle Class II malocclusion treated without extractions and with growth control.

  20. Soil parameters are key factors to predict metal bioavailability to snails based on chemical extractant data

    Energy Technology Data Exchange (ETDEWEB)

    Pauget, B.; Gimbert, F., E-mail: frederic.gimbert@univ-fcomte.fr; Scheifler, R.; Coeurdassier, M.; Vaufleury, A. de

    2012-08-01

    Although soil characteristics modulate metal mobility and bioavailability to organisms, they are often ignored in the risk assessment of metal transfer. This paper aims to determine the ability of chemical methods to assess and predict cadmium (Cd), lead (Pb) and zinc (Zn) environmental bioavailability to the land snail Cantareus aspersus. Snails were exposed in the laboratory for 28 days to 17 soils from around a former smelter. The soils were selected for their range of pH, organic matter, clay content, and Cd, Pb and Zn concentrations. The influence of soil properties on environmental availability (estimated using HF-HClO{sub 4}, EDTA, CaCl{sub 2}, NH{sub 4}NO{sub 3}, NaNO{sub 3}, free ion activity and total dissolved metal concentration in soil solution) and on environmental bioavailability (modelled using accumulation kinetics) was identified. Among the seven chemical methods, only the EDTA and the total soil concentration can be used to assess Cd and Pb environmental bioavailability to snails (r Superscript-Two {sub adj} = 0.67 and 0.77, respectively). For Zn, none of the chemical methods were suitable. Taking into account the influence of the soil characteristics (pH and CEC) allows a better prediction of Cd and Pb environmental bioavailability (r Superscript-Two {sub adj} = 0.82 and 0.83, respectively). Even though alone none of the chemical methods tested could assess Zn environmental bioavailability to snails, the addition of pH, iron and aluminium oxides allowed the variation of assimilation fluxes to be predicted. A conceptual and practical method to use soil characteristics for risk assessment is proposed based on these results. We conclude that as yet there is no universal chemical method to predict metal environmental bioavailability to snails, and that the soil factors having the greatest impact depend on the metal considered. - Highlights: Black-Right-Pointing-Pointer New approach to identify chemical methods able to predict metal bioavailability

  1. Ionic liquid-based extraction followed by graphite-furnace atomic absorption spectrometry for the determination of trace heavy metals in high-purity iron metal.

    Science.gov (United States)

    Matsumiya, Hiroaki; Kato, Tatsuya; Hiraide, Masataka

    2014-02-01

    The analysis of high-purity materials for trace impurities is an important and challenging task. The present paper describes a facile and sensitive method for the determination of trace heavy metals in high-purity iron metal. Trace heavy metals in an iron sample solution were rapidly and selectively preconcentrated by the extraction into a tiny volume of an ionic liquid [1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide] for the determination by graphite-furnace atomic absorption spectrometry (GFAAS). A nitrogen-donating neutral ligand, 2,4,6-tris(2-pyridyl)-1,3,5-triazine (TPTZ), was found to be effective in the ionic liquid-based selective extraction, allowing the nearly complete (~99.8%) elimination of the iron matrix. The combination with the optimized GFAAS was successful. The detectability reached sub-μg g(-1) levels in iron metal. The novel use of TPTZ in ionic liquid-based extraction followed by GFAAS was successfully applied to the determination of traces of Co, Ni, Cu, Cd, and Pb in certified reference materials for high-purity iron metal. © 2013 Published by Elsevier B.V.

  2. Turning the volume down on heavy metals using tuned diatomite. A review of diatomite and modified diatomite for the extraction of heavy metals from water

    Energy Technology Data Exchange (ETDEWEB)

    Danil de Namor, Angela F., E-mail: A.Danil-De-Namor@surrey.ac.uk [Instituto Nacional de Tecnologia Industrial, Parque Tecnologico Industrial Miguelete, Buenos Aires (Argentina); Department of Chemistry, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); El Gamouz, Abdelaziz [Department of Chemistry, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Frangie, Sofia; Martinez, Vanina; Valiente, Liliana [Instituto Nacional de Tecnologia Industrial, Parque Tecnologico Industrial Miguelete, Buenos Aires (Argentina); Webb, Oliver A. [Department of Chemistry, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Critical assessment of published work on raw and modified diatomites. Black-Right-Pointing-Pointer Counter-ion effect on the extraction of heavy metal speciation by diatomite. Black-Right-Pointing-Pointer Selection of the counter-ion by the use of existing thermodynamic data. Black-Right-Pointing-Pointer Enrichment of diatomites by attaching heavy metal selective functionalities. Black-Right-Pointing-Pointer Supramolecular chemistry for conferring selectivity to diatomites. - Abstract: Contamination of water by heavy metals is a global problem, to which an inexpensive and simple solution is required. Within this context the unique properties of diatomite and its abundance in many regions of the world have led to the current widespread interest in this material for water purification purposes. Defined sections on articles published on the use of raw and modified diatomite for the removal of heavy metal pollutants from water are critically reviewed. The capability of the materials as extracting agents for individual species and mixtures of heavy metals are considered in terms of the kinetics, the thermodynamics and the recyclability for both, the pollutant and the extracting material. The concept of 'selectivity' for the enrichment of naturally occurring materials such as diatomite through the introduction of suitable functionalities in their structure to target a given pollutant is emphasised. Suggestions for further research in this area are given.

  3. Review of algorithms for modeling metal distribution equilibria in liquid-liquid extraction processes

    Directory of Open Access Journals (Sweden)

    Lozano, L. J.

    2005-10-01

    Full Text Available This work focuses on general guidelines to be considered for application of least-squares routines and artificial neural networks (ANN in the estimation of metal distribution equilibria in liquid-liquid extraction process. The goal of the procedure in the statistical method is to find the values of the equilibrium constants (Kj for the reactions involved in the metal extraction which minimizes the differences between experimental distribution coefficient (Dexp and theoretical distribution coefficients according to the mechanism proposed (Dtheor- In the first part of the article, results obtained with the most frequently routine reported in the bibliography are compared with those obtained using the algorithms previously discussed. In the second part, the main features of a single back-propagation neural network for the same purpose are discussed, and the results obtained are compared with those obtained with the classical methods.

    El trabajo presenta las líneas generales a considerar para la estimación del equilibrio de distribución de metales en procesos de extracción líquido-líquido, según dos métodos: algoritmo clásico de mínimos cuadrados y redes neuronales artificiales. El objetivo del procedimiento, en el caso del método estadístico, es encontrar los valores de las constantes de equilibrio (Kj para las reacciones involucradas en la extracción del metal, que minimizan las diferencias entre el coeficiente de distribución experimental y el coeficiente de distribución teórico, de acuerdo al mecanismo propuesto. En la primera parte del artículo se comparan los resultados obtenidos a partir de los algoritmos usados más habitualmente en la bibliografía, con los datos obtenidos mediante el algoritmo previamente descrito. En la segunda parte, se presentan las características fundamentales para aplicar una red neuronal sencilla con algoritmo back-propagation y los

  4. Turning the volume down on heavy metals using tuned diatomite. A review of diatomite and modified diatomite for the extraction of heavy metals from water.

    Science.gov (United States)

    Danil de Namor, Angela F; El Gamouz, Abdelaziz; Frangie, Sofia; Martinez, Vanina; Valiente, Liliana; Webb, Oliver A

    2012-11-30

    Contamination of water by heavy metals is a global problem, to which an inexpensive and simple solution is required. Within this context the unique properties of diatomite and its abundance in many regions of the world have led to the current widespread interest in this material for water purification purposes. Defined sections on articles published on the use of raw and modified diatomite for the removal of heavy metal pollutants from water are critically reviewed. The capability of the materials as extracting agents for individual species and mixtures of heavy metals are considered in terms of the kinetics, the thermodynamics and the recyclability for both, the pollutant and the extracting material. The concept of 'selectivity' for the enrichment of naturally occurring materials such as diatomite through the introduction of suitable functionalities in their structure to target a given pollutant is emphasised. Suggestions for further research in this area are given. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Extraction of Micronutrient Metals from Peat-based Media Using Various Chelate-ligand and Iron-source Extractants

    Science.gov (United States)

    Objectives of the study were to determine effects of chelate-ligand (experiment 1) and iron-source (experiment 2) unbuffrered extractant solutions on substrate pH and Cu, Fe, Mn, and Zn extraction from peat-based media. Chelate-ligand extractants consisted of 5 mM solutions of ethylenediaminedisucc...

  6. SEM in applied marketing research

    DEFF Research Database (Denmark)

    Sørensen, Bjarne Taulo; Tudoran, Ana Alina

    In this paper we discuss two SEM approaches: an exploratory structural equation modelling based on a more liberalised and inductive philosophy versus the classical SEM based on the traditional hypothetical-deductive approach. We apply these two modelling techniques to data from a consumer survey ...

  7. Influence of different organic amendments on the potential availability of metals from soil: a study on metal fractionation and extraction kinetics by EDTA.

    Science.gov (United States)

    Santos, Sérgio; Costa, Carina A E; Duarte, Armando C; Scherer, Heinrich W; Schneider, Rudolf J; Esteves, Valdemar I; Santos, Eduarda B H

    2010-01-01

    The effects of long-term application of different organic amendments, as compared to mineral fertilizer, on Zn, Cu and Pb content and leachability in a luvisol derived from loess were assessed. The organic fertilizers, applied since 1962, were compost (COM) - from green organic household waste, sewage sludge (SLU) - from municipal water treatment facilities, farmyard manure (FYM) and the doses applied since 1997 were 90tha(-1), 10tha(-1) and 9tha(-1), once in 3years, respectively. The kinetics of metals extraction with 0.05moldm(-3) EDTA at pH 6.0 has been studied. The two first-order reactions model was fitted to the kinetic data and allowed to distinguish two pools for each metal: a "labile" fraction (Q(1)), quickly extracted with a rate constant k(1), and a "moderately labile" fraction (Q(2)), more slowly extracted, with a rate constant k(2). Simultaneously, the pseudo-total metal contents in the soil samples were determined after digestion with aqua regia (3:1 HCl+HNO(3)). The obtained parameters Q(1), k(1), Q(2), k(2), for the kinetics of extraction of each metal in the three replicates of each fertilization mode, as well as the pseudo-total metal contents, were statistically analysed. COM and SLU application resulted in an increase of the total contents of Pb, Zn and Cu in soil. Further, the percentage of labile Zn and Pb also increased in consequence of the application of those amendments, particularly COM. The increase was more noticeable for Zn. FYM, despite not increasing the total content of Pb, Zn or Cu, did also have an effect on the leachability of Zn and Pb, increasing their labile fraction in soil. These results point to a potential risk of increasing metals mobility in soil, mainly Zn, associated to the use of organic amendments, particularly COM or SLU.

  8. Antibacterial, anthelmintic and antioxidant activity of Argyreia elliptica extracts: Activity enhancement by the addition of metal salts

    Directory of Open Access Journals (Sweden)

    M K Prashanth

    2013-05-01

    Full Text Available Summary. Argyreia elliptica extracts were prepared with solvents at different polarity (petroleum ether, chloroform, ethyl acetate and methanol and evaluate their antibacterial, anthelmintic and antioxidant properties first time. An antioxidant activity was analyzed using different in vitro tests namely 2,2-diphenyl-1-picrylhydrazyl (DPPH and superoxide radical scavenging methods. Quantitative determination of phenols was carried out using spectrophotometric methods. In addition, the extracts were screened for their biological activity in absence and in presence of metal salts [Fe(III and Zn(II] ions. Results indicate that, the tested bacterial strains were most sensitive to the chloroform (CE and methanol extract (ME. Ethyl acetate (EA, CE and ME extracts showed potent radical scavenging activity. CE and ME extracts showed the highest total phenolic content and its enhanced anthelmintic and antioxidant activities were found in Fe(III combination. The extracts-Zn(II ion combination showed enhanced antibacterial activity against tested bacterial strains compare to the extracts alone.Industrial relevance. Herbal medicines have gained increasing attention worldwide for the treatment of various diseases because of their effectiveness and small side effects as compared to synthetic drugs. In general, the essential trace elements have been found to possess a very important role in biological system and also therapeutic activity depends on some trace elements. The present research reports the phytochemical screening of Argyrea elliptica leaves extracts. The antibacterial, anthilmentic and in vitro antioxidant activity activity of extracts and its metal salt combination was studied. The results scientifically establish the efficacy of the plant extracts and its metal salt combination as antibacterial, anthilmentic and antioxidant agents.Keywords. Argyreia elliptica; Antioxidant; Antibacterial activity; Total phenolic content.

  9. Pure metal extraction from molten oxide slag by short-circuit galvanic cell

    Institute of Scientific and Technical Information of China (English)

    Yunming Gao; Xingmin Guo; Kuochih Chou

    2004-01-01

    The oxygen-ion-permeable membrane galvanic short-circuit method has been developed, in which pure metal was directly extracted from the molten oxide slag, and no external voltage is applied. The galvanic cell employed in the experiment was as follows: graphite rod|[O]Fe+C saturation|ZrO2(MgO)|(FeO)(siag) |Fe rod. The reduction current in the galvanic cell consisted of an external short-circuit current and an interior short-circuit current in the oxygen-ion-permeable membrane. The real-time variation of external circuit reduction ratio of the molten slag could be obtained from the curve of the external circuit current to the time.

  10. Partial alkali-metal ion extraction from K0.8(Li0.27Ti1.73)O4 using PTFE as an extraction reagent.

    Science.gov (United States)

    Ozawa, Tadashi C; Sasaki, Takayoshi

    2014-10-21

    The alkali-metal ion extraction ability of an inert material, polytetrafluoroethylene (PTFE; empirical formula CF2), was clarified by characterizing a partially alkali-metal ion-extracted layered compound, K0.8(Li0.27Ti1.73)O4. Washing K0.8(Li0.27Ti1.73)O4 in water extracts only 44% of the interlayer K(+) and no intralayer Li(+); on the other hand, 53% of the interlayer K(+) and approximately 10% of the intralayer Li(+) ions were extracted from K0.8(Li0.27Ti1.73)O4 by the reaction with PTFE at 350 °C under flowing Ar. A systematic decrease in the lattice parameters a and c along the intralayer directions and an increase in b along the interlayer direction were observed, consistent with the alkali-metal ion deintercalation amount as a function of the reaction temperatures and the reacted PTFE amounts. After the reaction with K0.8(Li0.27Ti1.73)O4 : CF2 = 1 : 0.6 in mol, the lattice parameter b increased to 1.5607(3) nm from 1.5522(2) of the pristine K0.8(Li0.27Ti1.73)O4, and this change in the lattice parameter was approximately one order of magnitude larger than those in a and c.

  11. SiO2-coated magnetic graphene oxide modified with polypyrrole-polythiophene: A novel and efficient nanocomposite for solid phase extraction of trace amounts of heavy metals.

    Science.gov (United States)

    Molaei, Karam; Bagheri, Hasan; Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira; Shamsipur, Mojtaba

    2017-05-15

    The synthesis of a novel nanocomposite comprised of SiO2-coated magnetic graphene oxide modified with a pyrrole-thiophene (mGO/SiO2@coPPy-Th) copolymer is reported in the present work. The nanocomposite was applied for the fast magnetic solid phase extraction (MSPE) of trace levels of copper, lead, chromium, zinc and cadmium from water and agricultural samples. The nanocomposite was prepared in three steps: (1) decoration of graphene oxide sheets with magnetite nanoparticles thorough a facile one-step chemical reaction strategy; (2) chemical grafting by a silica layer to obtain high stability in acidic solutions; and (3) surface modification by coPPy-Th via simultaneous oxidation polymerization of pyrrole and thiophene in the presence of mGO/SiO2 composite. The nanocomposite was subsequently characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and vibrating sample magnetometry (VSM) techniques. Several important experimental variables that could affect MSPE performance, including the pH of the sample, sorption time, sorbent dosage, eluent type and its concentration, eluent volume and elution time, were investigated and optimized. Under optimal conditions, the limits of detection for the target heavy metals ranged from 0.15 to 0.65μgL(-1). The maximum sorption capacity of the mGO/SiO2@coPPy-Th nanocomposite was 201, 230, 125, 98 and 80mgg(-1) for Cu(II), Pb(II), Zn(II), Cr(III) and Cd(II), respectively. Finally, the feasibility of the proposed method was investigated for the extraction and determination of the target metals from real matrices.

  12. Composition and clues to the origin of refractory metal nuggets extracted from chondritic meteorites

    Science.gov (United States)

    Schwander, D.; Berg, T.; Harries, D.; Schönhense, G.; Ott, U.

    2014-10-01

    Refractory metal nuggets (RMNs) contain elements, such as Os, Ir, Mo, and Ru, which are predicted to condense from a cooling gas of solar composition simultaneously with CAI-minerals. Berg et al. identified a large number of RMNs in acid-resistant residues of the Murchison meteorite and suggested that they are pristine condensates. In extending the work of these authors, we have improved the chemical extraction process to enrich the concentration of RMNs in the residue sample and prepared three additional RMN-rich residues from the chondritic meteorites Murchison, Allende, and Leoville. The results show that, while their origin is clearly solar, the compositions in detail of RMNs from all three meteorites do not match well with a simple condensation model based on equilibrium thermodynamics and ideal solid solution of all metals. Thus, we find that a primary formation by direct condensation, as suggested previously, is unlikely for most of the studied grains and that alternative scenarios should be considered in future work. The results also show that several, but not all, alloys from Allende and Leoville have undergone processes, such as metamorphic oxidation and sulfidization in the meteoritic environment, in which they lost, e.g., W and Mo. For Murchison and several Leoville and Allende RMNs, we propose a pristine nature.

  13. Fractionation and sequential extraction of heavy metals in the soil of scrapyard of discarded vehicles.

    Science.gov (United States)

    Jaradat, Qasem M; Massadeh, Adnan M; Zaitoun, Mohammed A; Maitah, Baheyah M

    2006-01-01

    Chemical and physical size fractionation of heavy metals were carried out on 20 soil samples from the scrap yard area. Tessier method was used in sequential extraction. Cadmium showed the highest levels among the other elements studied in the exchangeable fraction (about 33%), while other elements showed low levels in this fraction (> or =1%). Lead and manganese were mostly found in the Fe-Mn oxide fraction, zinc and iron were mostly in residual fraction, while copper was mostly found in the organic fraction of the soil. Soil samples were size-fractionated into four sizes: 1000-500, 500-125, 125-53, and less than 53 microm. The highest levels of Fe, Cu, Pb, Mn, and Cd were found in the medium fraction (500-125 mum), while zinc showed its highest levels in the fine fraction (125-53 microm). The order of heavy metal load in the size fractions was found to be medium > fine > coarse > silt for Fe, Mn, Cu, Pb, and Cd, where it was found as fine > medium > coarse > silt for zinc.

  14. Selective extraction of heavy metals from two real calcium-rich contaminated soils by a modified NTA.

    Science.gov (United States)

    Picard, François; Chaouki, Jamal

    2016-11-15

    The objective of this work is to evaluate the selectivity and solubility of a buffer chelant. The buffer chelant is ethylenediamine-nitrilotriacetic acid (NTA·3EDA) and its performance is compared to NTA. All experiments were conducted on batches of 25g of soil in an autoclave at 25°C or 75°C with a constant L:S ratio of 2. The experiments were conducted under a CO2 overhead to lower the reaction pH. The buffer chelant allows a 5-fold selectivity increase for heavy metals while increasing or maintaining the same molar extraction yield compared to NTA. These selectivity and extraction results stand out from those obtained with other neutralized NTA. NTA, EDA and the acid gas CO2 are the three necessary ligands in the NTA·3EDA extraction mechanism. A reaction temperature setpoint increase causes a higher Fe dissolution. However, this does not lower the NTA and NTA·3EDA selectivity for heavy metals. Thus, Fe is a non-interfering cation in the NTA and NTA·3EDA extraction mechanisms. This non-interference is less apparent in the NTA extraction mechanism. The present work intends to share another perspective on the design of more selective and soluble chelants for heavy metal extraction.

  15. Solid-phase extraction with metal-organic frameworks for the analysis of chiral compounds.

    Science.gov (United States)

    Tang, Bo; Zhang, Jun-Hui; Zi, Min; Chen, Xue-Xian; Yuan, Li-Ming

    2016-12-01

    Metal-organic frameworks (MOFs) are excellent porous materials with nanoscale cavities and high surface areas, which make them promising as novel adsorbents in solid-phase extraction (SPE). In this article we report a new application of the chiral MOF [Zn2 (D-Cam)2 (4,4'-bpy)]n in SPE used for the measurement of the enantiomeric excess (ee) of (±)-1,1'-bi-2-naphthol. Several important experimental parameters that may influence the extraction efficiency were investigated and optimized. Under the optimum conditions, a good linearity (R(2)  > 0.999) was found between the ee value and the reciprocal of the peak areas. When compared with the actual ee measured using chiral HPLC, the SPE-based assay also showed good accuracy and precision. The results showed that SPE based on chiral MOFs as adsorbents is a simple and effective method for the determination of the ee values of chiral compounds. © 2016 Wiley Periodicals, Inc.

  16. A New Emulsion Liquid Membrane Based on a Palm Oil for the Extraction of Heavy Metals

    Directory of Open Access Journals (Sweden)

    Sanna Björkegren

    2015-04-01

    Full Text Available The extraction efficiency of hexavalent chromium, Cr(VI, from water has been investigated using a vegetable oil based emulsion liquid membrane (ELM technique. The main purpose of this study was to create a novel ELM formulation by choosing a more environmentally friendly and non-toxic diluent such as palm oil. The membrane phase so formulated includes the mobile carrier tri-n-octylmethylammonium chloride (TOMAC, to facilitate the metal transport, and the hydrophilic surfactant Tween 80 to facilitate the dispersion of the ELM phase in the aqueous solution. Span 80 is used as surfactant and butanol as co-surfactant. Our results demonstrate that this novel ELM formulation, using the vegetable palm oil as diluent, is useful for the removal of hexavalent chromium with an efficiency of over 99% and is thus competitive with the already existing, yet less environmentally friendly, ELM formulations. This result was achieved with an optimal concentration of 0.1 M NaOH as stripping agent and an external phase pH of 0.5. Different water qualities have also been investigated showing that the type of water (deionized, distilled, or tap water does not significantly influence the extraction rate.

  17. Recovery of metal values from spent lithium-ion batteries with chemical deposition and solvent extraction

    Science.gov (United States)

    Nan, Junmin; Han, Dongmei; Zuo, Xiaoxi

    This paper describes a new recycling process of metal values from spent lithium-ion batteries (LIBs). After the dismantling of the spent batteries steel crusts, the leaching of battery internal substances with alkaline solution and the dissolving of the residues with H 2SO 4 solution were carried out. Then mass cobalt was chemically deposited as oxalate, and Acorga M5640 and Cyanex272 extracted the small quantities of copper and cobalt, respectively. Lithium was recovered as deposition of lithium carbonate. It is shown that about 90% cobalt was deposited as oxalate with less than 0.5% impurities, and Acorga M5640 and Cyanex272 were efficient and selective for the extraction of copper and cobalt in sulfate solution. Over 98% of the copper and 97% of the cobalt was recovered in the given process. In addition, the waste solution was treated innocuously, and LiCoO 2 positive electrode material with good electrochemical performance was also synthesized by using the recovered compounds of cobalt and lithium as precursors. The process is feasible for the recycling of spent LIBs in scale-up.

  18. Distribution and sequential extraction of some heavy metals in urban soils of Guiyang City, China

    Institute of Scientific and Technical Information of China (English)

    WU Yongfeng; LIU Congqiang; TU Chenglong

    2008-01-01

    Sixty-two soil samples collected from different functional zones of Guiyang were analyzed for total concentrations and sequential extraction of Cr, Cu, Pb, Zn and Cd by ICP spectrometry. The average total concentrations of Cr, Cu, Pb, Zn and Cd in the soils of Guiyang were 92.9, 51.6, 44.1, 139.3 and 0.28 mg/kg, respectively. The soils have been polluted by Cr, Cu, Pb, Zn and Cd to some extent in comparison with the background values of Guiyang. Significant differences were recognized in the concentrations of Cr, Cu, Pb, Zn and Cd in different functional zones. As for the sequential extraction, Cr, Cu and Zn were present mainly in the residual fraction, and Pb was present mainly in the oxidizable fraction. The reducible fraction of Cd accounts for 47.5%, and the residual fraction is lowest. The mobility and bioavailability of heavy metals follow the order of Cd>Pb>Cu>Cr>Zn.

  19. Liquid-liquid extraction and separation of total rare earth (RE) metals from polymetallic manganese nodule leaching solution

    Institute of Scientific and Technical Information of China (English)

    PK Parhi; KH Park; CW Nam; JT Park

    2015-01-01

    The study on the solvent extraction for quantitative and selective separation of total rare earth metals from the polymetallic nodule leach liquor was investigated. The typical leach liquor bearing 0. 094 g/L total rare earth, 0. 23 g/L Mn, 0.697 g/L Cu, 0.2 g/L Fe, 0.01 g/L Co and 0.735 g/L Ni was subjected to the removal iron content by precipitation method using Ca(OH)2 at pH 3.95, prior to solvent extraction of rare earth metals. Three different organo-phosphoric acid reagents (D2EHPA, PC88A, Cyanex 272) were used to ascertain their performances and selectivity towards the loading of rare earth metals in presence of other base metals. Based on the results of eq. pH effect, the performances of above three extractants followed the order as:D2EHPA>PC88A>Cyanex 272. To ensure the absence of extraction of base metals (Cu, Co, Ni), the eq. pH of the solution was optimized at the level of 2.21, though higher rare earth metal extraction efficiency was observed at higher eq. pH with either of the extractants. The complete process flow diagram for substantial recovery of total rare earth was developed using D2EHPA. Extraction isotherm plot was constructed at A:O=12:1, 3-stages and pHe=2.21, using 0.8 mol/L D2EHPA and the predicted condition of this study was further confirmed by 6-Cycles Counter Current Simulation (CCS) study. The stripping of total rare earth from loaded organic phase (LO) was conducted using HCl solution. Mc-Cabe Thiele diagram study carried out at A:O=1:5 using 4 mol/L HCl showed that three theoretical stages were needed for quantitative stripping of total rare earth. The subsequent stripped solution resulted thus led to contain total rare earth of 5.6 g/L indicating a very high enrichment of total metals by solvent extraction (SX) process.

  20. Automatic In-Syringe Dispersive Microsolid Phase Extraction Using Magnetic Metal-Organic Frameworks.

    Science.gov (United States)

    Maya, Fernando; Palomino Cabello, Carlos; Estela, Jose Manuel; Cerdà, Víctor; Turnes Palomino, Gemma

    2015-08-04

    A novel automatic strategy for the use of micro- and nanomaterials as sorbents for dispersive microsolid phase extraction (D-μ-SPE) based on the lab-in-syringe concept is reported. Using the developed technique, the implementation of magnetic metal-organic framework (MOF) materials for automatic solid-phase extraction has been achieved for the first time. A hybrid material based on submicrometric MOF crystals containing Fe3O4 nanoparticles was prepared and retained in the surface of a miniature magnetic bar. The magnetic bar was placed inside the syringe of an automatic bidirectional syringe pump, enabling dispersion and subsequent magnetic retrieval of the MOF hybrid material by automatic activation/deactivation of magnetic stirring. Using malachite green (MG) as a model adsorption analyte, a limit of detection of 0.012 mg/L and a linear working range of 0.04-2 mg/L were obtained for a sample volume equal to the syringe volume (5 mL). MG preconcentration was linear up to a volume of 40 mL, obtaining an enrichment factor of 120. The analysis throughput is 18 h(-1), and up to 3000 extractions/g of material can be performed. Recoveries ranging between 95 and 107% were obtained for the analysis of MG in different types of water and trout fish samples. The developed automatic D-μ-SPE technique is a safe alternative for the use of small-sized materials for sample preparation and is readily implementable to other magnetic materials independent of their size and shape and can be easily hyphenated to the majority of detectors and separation techniques.

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

    Science.gov (United States)

    Yang, Xing; Liu, Jingjing; McGrouther, Kim; Huang, Huagang; Lu, Kouping; Guo, Xi; He, Lizhi; Lin, Xiaoming; Che, Lei; Ye, Zhengqian; Wang, Hailong

    2016-01-01

    Biochar is a carbon-rich solid material derived from the pyrolysis of agricultural and forest residual biomass. Previous studies have shown that biochar is suitable as an adsorbent for soil contaminants such as heavy metals and consequently reduces their bioavailability. However, the long-term effect of different biochars on metal extractability or soil health has not been assessed. Therefore, a 1-year incubation experiment was carried out to investigate the effect of biochar produced from bamboo and rice straw (at temperatures ≥500 °C) on the heavy metal (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) extractability and enzyme activity (urease, catalase, and acid phosphatase) in a contaminated sandy loam paddy soil. Three rates (0, 1, and 5%) and two mesh sizes (straw biochar significantly (P straw biochar significantly (P straw biochar resulted in the greatest reductions of extractable Cu and Zn, 97.3 and 62.2%, respectively. Both bamboo and rice straw biochar were more effective at decreasing extractable Cu and Pb than removing extractable Cd and Zn from the soil. Urease activity increased by 143 and 107% after the addition of 5% coarse and fine rice straw biochars, respectively. Both bamboo and rice straw biochars significantly (P impact on acid phosphatase activity. In conclusion, the rice straw biochar had greater potential as an amendment for reducing the bioavailability of heavy metals in soil than that of the bamboo biochar. The impact of biochar treatment on heavy metal extractability and enzyme activity varied with the biochar type, application rate, and particle size.

  2. Carbon nanotubes as solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: A review

    Energy Technology Data Exchange (ETDEWEB)

    Herrero Latorre, C., E-mail: carlos.herrero@usc.es [Universidad de Santiago de Compostela, Dpto. Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Alfonso X el Sabio s/n, 27002 Lugo (Spain); Alvarez Mendez, J.; Barciela Garcia, J.; Garcia Martin, S.; Pena Crecente, R.M. [Universidad de Santiago de Compostela, Dpto. Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Alfonso X el Sabio s/n, 27002 Lugo (Spain)

    2012-10-24

    Highlights: Black-Right-Pointing-Pointer The use of CNTs as sorbent for metal species in solid phase extraction has been described. Black-Right-Pointing-Pointer Physical and chemical strategies for functionalization of carbon nanotubes have been discussed. Black-Right-Pointing-Pointer Published analytical methods concerning solid phase extraction and atomic spectrometric determination have been reviewed. - Abstract: New materials have significant impact on the development of new methods and instrumentation for chemical analysis. From the discovery of carbon nanotubes in 1991, single and multi-walled carbon nanotubes - due to their high adsorption and desorption capacities - have been employed as sorption substrates in solid-phase extraction for the preconcentration of metal species from diverse matrices. Looking for successive improvements in sensitivity and selectivity, in the past few years, carbon nanotubes have been utilized as sorbents for solid phase extraction in three different ways: like as-grown, oxidized and functionalized nanotubes. In the present paper, an overview of the recent trends in the use of carbon nanotubes for solid phase extraction of metal species in environmental, biological and food samples is presented. The determination procedures involved the adsorption of metals on the nanotube surface, their quantitative desorption and subsequent measurement by means of atomic spectrometric techniques such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry/mass spectrometry, among others. Synthesis, purification and types of carbon nanotubes, as well as the diverse chemical and physical strategies for their functionalization are described. Based on 140 references, the performance and general properties of the applications of solid phase extraction based on carbon nanotubes for metal species atomic spectrometric determination are discussed.

  3. Metal extractability patterns to evaluate (potentially) mobile fractions in periurban calcareous agricultural soils in the Mediterranean area-analytical and mineralogical approaches.

    Science.gov (United States)

    de Santiago-Martín, Ana; Valverde-Asenjo, Inmaculada; Quintana, Jose R; Vázquez, Antonio; Lafuente, Antonio L; González-Huecas, Concepción

    2013-09-01

    A set of periurban calcareous agricultural Mediterranean soils was spiked with a mixture of Cd, Cu, Pb and Zn at two levels within the limit values proposed by current European legislation, incubated for up to 12 months, and subjected to various one-step extraction procedures to estimate mobile (neutral salts) and potentially mobile metal fractions (complexing and acidic extraction methods). The results obtained were used to study metal extractability patterns according to the soil characteristics. The analytical data were coupled with mineralogical investigations and speciation modelling using the Visual Minteq model. The formation of soluble metal-complexes in the complexing extracts (predicted by the Visual Minteq calculations) led to the highest extraction efficiency with complexing extractants. Metal extractability patterns were related to both content and composition of carbonate, organic matter, Fe oxide and clay fractions. Potentially mobile metal fractions were mainly affected by the finest soil fractions (recalcitrant organic matter, active lime and clay minerals). In the case of Pb, scarce correlations between extractable Pb and soil constituents were obtained which was attributed to high Pb retention due to the formation of 4PbCO3·3PbO (corroborated by X-ray diffraction). In summary, the high metal proportion extracted with complexing agents highlighted the high but finite capacity to store potentially mobilizable metals and the possible vulnerability of these soils against environmental impact from metal accumulation.

  4. Remediation Performance and Mechanism of Heavy Metals by a Bottom-up Activation and Extraction System Using Multiple Biochemical Materials.

    Science.gov (United States)

    Xiao, Kemeng; Li, Yunzhen; Sun, Yang; Liu, Ruyue; Li, Junjie; Zhao, Yun; Xu, Heng

    2017-08-24

    Soil contamination with heavy metals has caused serious environmental problems and increased the risks to humans and biota. Herein, we developed an effective bottom-up metals removal system, which was based on the synergy between the activation of immobilization metals resistant bacteria (B) and the extraction of bio-accumulator material (Stropharia rugoso-annulata). In this system, the advantages of biochar (BC) produced at 400 ℃ and sodium alginate (SA) were integrated to immobilize bacteria. Optimized by response surface methodology (RSM), the biochar and the bacterial suspension were mixed with the ratio of 1:20 (w:v) for 12 hours when 2.5% sodium alginate was added into the mixture. Results demonstrated the system significantly increased the proportion of acid soluble Cd and Cu, and improved the soil micro-ecology (microbial counts, soil respiration and enzyme activities). The maximum extraction of Cd and Cu were 8.79 mg kg-1 and 77.92 mg kg-1, respectively. Besides, details of the possible mechanistic insight to the metals removal were discussed, which indicated it was positively correlated with the acetic acid (HOAc) extractable metals and soil micro-ecology. Meanwhile, the "dilution effect" in Stropharia rugoso-annulata probably played an important role in metals removal process. Furthermore, the metals resistant bacteria in this system were successfully colonized and the soil bacteria community were evaluated to understand the microbial diversity in metals contaminated soils after remediation. Soil contamination with heavy metals has caused serious environmental problems and increased the risks to humans and biota. Herein, we developed an effective bottom-up metals removal system, which was based on the synergy between the activation of immobilization metals resistant bacteria (B) and the extraction of bio-accumulator material (Stropharia rugoso-annulata). In this system, the advantages of biochar (BC) produced at 400 ℃ and sodium alginate (SA) were

  5. X-ray fluorescence analysis of trace metal ions following a preconcentration of metal-diethyldithiocarbamate complexes by homogeneous liquid-liquid extraction

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Atsushi; Igarashi, Shukuro; Ueki, Yasuo [Ibaraki Univ., Hitachi (Japan). Faculty of Engineering; Yamaguchi, Hitoshi [National Research Inst. for Metals, Ibaraki (Japan)

    2000-11-01

    A homogeneous liquid-liquid extraction method for 36 metal ions with diethyldithiocarbamate was studied. As a result, 11 metal ions were extracted as metal-chelates. Under the experimental conditions, the maximum concentration factor was 500 (i.e., 0.1 mL of sedimented liquid phase was produced from 50 mL of aqueous phase). Moreover, the proposed method was utilized as a preconcentration method for X-ray fluorescence analysis of these metals. The recovery of each metal was ca. 97-100%. All calibration curves were linear over the range of 5.0 x 10{sup -7} mol L{sup -1} to 1.0 x 10{sup -5} mol L{sup -1}. The detection limits were at the 10{sup -8} mol L{sup -1} levels and the relative standard deviations were below 5% (5 determinations). When the proposed method was used for the determination of contaminants in a synthetic sample (Al-based alloy model) and of components in an Au-Pd alloy, the results were satisfactory. (orig.)

  6. Dispersive micro-solid-phase extraction of herbicides in vegetable oil with metal-organic framework MIL-101.

    Science.gov (United States)

    Li, Na; Zhang, Liyuan; Nian, Li; Cao, Bocheng; Wang, Zhibing; Lei, Lei; Yang, Xiao; Sui, Jiaqi; Zhang, Hanqi; Yu, Aimin

    2015-03-04

    Dispersive microsolid-phase extraction based on metal-organic framework has been developed and applied to the extraction of triazine and phenylurea herbicides in vegetable oils in this work. The herbicides were directly extracted with MIL-101 from diluted vegetables oils without any further cleanup. The separation and determination of herbicides were carried out on high performance liquid chromatography. The effects of experimental parameters, including volume ratio of n-hexane to oil sample, mass of MIL-101, extraction time, centrifugation time, eluting solvent, and elution time were investigated. The Student's t test was applied to evaluate the selected experimental conditions. The limits of detection for the herbicides ranged from 0.585 to 1.04 μg/L. The recoveries of the herbicides ranged from 87.3 to 107%. Our results showed that the present method is rapid, simple, and effective for extracting herbicides in vegetable oils.

  7. On-site solid-phase extraction and application to in situ preconcentration of heavy metals in surface water.

    Science.gov (United States)

    Jiao, Fang; Gao, Hong-Wen

    2013-01-01

    An on-site solid-phase extraction, consisting of the sorption, the separation and the elution function units, was designed for in situ preconcentration of heavy metals ions. The D401 resin powder was employed as sorbent to capture Pb(2+), Cu(2+), Zn(2+), Cd(2+), Co(2+), and Ni(2+), and then they desorbed with 2 mol/L nitric acid as eluent. Under the optimized conditions, these heavy metals ions in West Lake, Taihu Lake, and Yangtze River of China were captured and then determined by ICP-OES with the recovery of 92.5% to 111.5%. The on-site solid-phase extraction achieved a quick preconcentration of heavy metals to avoid the transport and storage of a large volume water sample. It is suitable for in situ monitoring of water quality in mountains, tablelands or other remote areas.

  8. A Compilation of Metals and Trace Elements Extracted from Materials Relevant to Pharmaceutical Applications such as Packaging Systems and Devices.

    Science.gov (United States)

    Jenke, Dennis; Rivera, Christine; Mortensen, Tammy; Amin, Parul; Chacko, Molly; Tran, Thang; Chum, James

    2013-01-01

    Nearly 100 individual test articles, representative of materials used in pharmaceutical applications such as packaging and devices, were extracted under exaggerated conditions and the levels of 32 metals and trace elements (Ag, Al, As, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ge, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, V, Zn, and Zr) were measured in the extracts. The extracting solvents included aqueous mixtures at low and high pH and an organic solvent mixture (40/60 ethanol water). The sealed vessel extractions were performed by placing an appropriate portion of the test articles and an appropriate volume of extracting solution in inert extraction vessels and exposing the extraction units (and associated extraction blanks) to defined conditions of temperature and duration. The levels of extracted target elements were measured by inductively coupled plasma atomic emission spectroscopy. The overall reporting threshold for most of the targeted elements was 0.05 μg/mL, which corresponds to 0.5 μg/g for the most commonly utilized extraction stoichiometry (1 g of material per 10 mL of extracting solvent). The targeted elements could be classified into four major groups depending on the frequency with which they were present in the over 250 extractions reported in this study. Thirteen elements (Ag, As, Be, Cd, Co, Ge, Li, Mo, Ni, Sn, Ti, V, and Zr) were not extracted in reportable quantities from any of the test articles under any of the extraction conditions. Eight additional elements (Bi, Cr, Cu, Mn, Pb, Sb, Se, and Sr) were rarely extracted from the test articles at reportable levels, and three other elements (Ba, Fe, and P) were infrequently extracted from the test articles at reportable levels. The remaining eight elements (Al, B, Ca, Mg, Na, S, Si, and Zn) were more frequently present in the extracts in reportable quantities. These general trends in accumulation behavior were compared to compiled lists of elements of concern as impurities in

  9. Migration, speciation and distribution of heavy metals in an oil-polluted soil affected by crude oil extraction processes.

    Science.gov (United States)

    Fu, Xiaowen; Cui, Zhaojie; Zang, Guolong

    2014-07-01

    Heavy metals are among the major pollutants in the worldwide soil environment. In oilfields, the crude oil extraction process results in the simultaneous contamination of the soil with petroleum and heavy metals. In this work, we investigated the influence of oil extraction on the migration, speciation, and temporal distribution of heavy metals (Cu, Zn, Pb, Cd, Cr, Mn, Ni, V, and Mn) in soils of an oil region of Shengli Oilfield, China. The results showed that oil-polluted soils were contaminated with Cu, Zn, Cd and Ni, with mean concentrations of 27.63, 67.12, 0.185 and 33.80 mg kg(-1), respectively (greater than the background values of local surface soils). Compared with the control profile, the vertical distributions of Cu, Zn, Pb, Cd, Ni, and V were affected in oil-polluted soils, particularly those of Cd and Ni. The concentrations of Zn, Cd, Ni, V, and Mn in oil-polluted soils increased with the duration of oil well development, which indicated the levels of these metals in the oil field were enhanced by human activities. Fractionation analysis revealed that the mobility potential of heavy metals in oil polluted soil decreased in the sequence Cd > Mn > Zn > Ni > Pb > Cu > Cr > V. The most important proportion of Cd is ion exchangeable and acid soluble, which indicates that Cd is the most labile, available, and harmful heavy metal among the elements that damage the soil environment in oil-polluted soil.

  10. Speciation of Heavy Metals by Modified BCR Sequential Extraction in Soils Contaminated by Phosphogypsum in Sfax, Tunisia

    Directory of Open Access Journals (Sweden)

    Ahmed Wali

    2015-01-01

    Full Text Available The accumulation of trace metals in soil is a serious environmental problem that creates a hazard when metals are transferred to water or plants. To understand the mobility and bioavailability of trace metals, the concentrations and distributions of trace metals must be established for different physical and chemical phases of the soil. We determined the concentrations of trace metals (Zn, Pb, Cu, Cr, Co, Ni, Mn, and Fe in soil using the sequential extraction method recommended by Community Bureau of Reference (BCR and analysed chemical properties, such as the pH, cation exchange capacity, total organic carbon, electrical conductivity, and calcium carbonate. Our results revealed higher concentrations of trace metals in topsoil samples (0–20 cm than in subsoil samples (20–40 cm and 40–60 cm for most metals at four sites. Zn in the topsoil was mostly associated with the non-resistant fraction at all sites. Approximately 60% more Pb was bound to the non-residual, exchangeable and reducible fractions at all sites, and soil depths. Cr, Cu, Ni and Fe were mainly in the residual fraction, whereas Mn was largely present in the non-resistant fraction. The global contamination factor of trace metals decreased with soil depth. The mobility and bioavailability were greatest for Zn, followed by Cu and Pb. DOI: http://dx.doi.org/10.5755/j01.erem.70.4.7807

  11. The extraction of zinc and other minor metals from concentrated ammonium chloride solutions with D2EHPA and Cyanex 272

    Directory of Open Access Journals (Sweden)

    Amer, S.

    1995-12-01

    Full Text Available A comparative study is made of the extractants D2EHPA and Cyanex 272 for the zinc and minor metal extraction from aqueous concentrated ammonium chloride solutions, as those of the leaching liquors of the CENIM-LNETI process. Extraction equilibrium data for zinc are presented as extraction isotherms at constant pH and at a temperature of 50 °C. Zinc extraction and coextraction of minor metal ions as Cu, Ca, Pb, Mg, Cd, Co, Ni and Hg are studied. Mercury does not extract from concentrated ammonium chloride solutions. Cyanex 272 shows a better selectivity for zinc with regard to the minor metals than D2EHPA, which is especially remarkable for calcium, the most coextracted element by D2EHPA. Nickel and cadmium coextraction is negligible for both extractants. The possible use of the Cyanex 272 as an alternative to D2EHPA is considered.

    Se realiza un estudio comparativo del comportamiento del D2EHPA y del Cyanex 272 durante la extracción del cinc y otros metales minoritarios de soluciones acuosas concentradas de cloruro amónico, como las de las soluciones de lixiviación del proceso CENIM-LNETI. Se presentan los datos de equilibrio de extracción del cinc en forma de isotermas de extracción a una temperatura de 50 °C y pH constante y se estudia la coextracción de los metales minoritarios Cu, Ca, Pb, Mg, Cd, Co, Ni y Hg. El mercurio no se extrae de las soluciones concentradas de cloruro amónico. La selectividad del Cyanex 272 para el cinc respecto de esos metales minoritarios es mejor que la del D2EHPA, siendo verdaderamente notable para el calcio, que es la impureza que más se coextrae con el D2EHPA. La coextracción de níquel y de cadmio es muy pequeña para ambos extractantes. Se considera la posibilidad del uso alternativo del Cyanex 272 en lugar del D2EHPA.

  12. Hybrid OPC modeling with SEM contour technique for 10nm node process

    Science.gov (United States)

    Hitomi, Keiichiro; Halle, Scott; Miller, Marshal; Graur, Ioana; Saulnier, Nicole; Dunn, Derren; Okai, Nobuhiro; Hotta, Shoji; Yamaguchi, Atsuko; Komuro, Hitoshi; Ishimoto, Toru; Koshihara, Shunsuke; Hojo, Yutaka

    2014-03-01

    Hybrid OPC modeling is investigated using both CDs from 1D and simple 2D structures and contours extracted from complex 2D structures, which are obtained by a Critical Dimension-Scanning Electron Microscope (CD-SEM). Recent studies have addressed some of key issues needed for the implementation of contour extraction, including an edge detection algorithm consistent with conventional CD measurements, contour averaging and contour alignment. Firstly, pattern contours obtained from CD-SEM images were used to complement traditional site driven CD metrology for the calibration of OPC models for both metal and contact layers of 10 nm-node logic device, developed in Albany Nano-Tech. The accuracy of hybrid OPC model was compared with that of conventional OPC model, which was created with only CD data. Accuracy of the model, defined as total error root-mean-square (RMS), was improved by 23% with the use of hybrid OPC modeling for contact layer and 18% for metal layer, respectively. Pattern specific benefit of hybrid modeling was also examined. Resist shrink correction was applied to contours extracted from CD-SEM images in order to improve accuracy of the contours, and shrink corrected contours were used for OPC modeling. The accuracy of OPC model with shrink correction was compared with that without shrink correction, and total error RMS was decreased by 0.2nm (12%) with shrink correction technique. Variation of model accuracy among 8 modeling runs with different model calibration patterns was reduced by applying shrink correction. The shrink correction of contours can improve accuracy and stability of OPC model.

  13. Preparation and characterization of magnetic allylamine modified graphene oxide-poly(vinyl acetate-co-divinylbenzene) nanocomposite for vortex assisted magnetic solid phase extraction of some metal ions.

    Science.gov (United States)

    Khan, Mansoor; Yilmaz, Erkan; Sevinc, Basak; Sahmetlioglu, Ertugrul; Shah, Jasmin; Jan, Muhammad Rasul; Soylak, Mustafa

    2016-01-01

    Magnetic allylamine modified graphene oxide-poly(vinyl acetate-co-divinylbenzene) (MGO-DVB-VA) was synthesized and used for magnetic solid phase extraction of Pb(II), Cd(II), Cu(II), Ni(II) and Co(II) prior to their determination by flame atomic absorption spectroscopy. The adsorbent surface functional group was characterized by using FT-IR and Raman spectroscopy. XRD pattern was used to determine the layers of GO. Surface morphology and elemental composition of the adsorbent were evaluated by using SEM and EDX analysis. Various parameters, effecting adsorption efficiency like initial solution pH, adsorbent dose, type and volume of eluent, volume of sample and diverse ions effects were optimized. The preconcentration factor (PF) is 40 for all the metals and the limits of detection for Pb, Cd, Cu, Ni and Co are in the range of 0.37-2.39 µg L(-1) and relative standard deviation below 3.1%. The method was validated by using the method for certified reference materials (Tobacco Leaves (INCT-OBTL-5), Tomato Leaves (1573a), Certified Water (SPS-ww2) and Certified Water (TMDA 64-2)). The method was successfully applied for natural water and food samples.

  14. Molecular Design of Crown Ethers.22.Synthesis of Benzocrown Ether Derivatives and Their Solvent Extraction with Univalent/Bivalent Metal Picrates

    Institute of Scientific and Technical Information of China (English)

    YANG,Ying-Wei(杨英威); LI,Chun-Ju(李春举); ZHANG,Heng-Yi(张衡益); LIU,Yu(刘育)

    2004-01-01

    Three novel benzocrown ether derivatives have been synthesized and their cation binding behavior with uniand bi-valent metal ions was evaluated by the solvent extraction of aqueous metal picrates. The obtained results indicate that the size-fit of crown ether and metal cation, and electron effect of the side arm attached to benzocrown ethers affect their cation binding ability and selectivity.

  15. Speciation and cysteine-simplified physiological-based extraction technique (SBET) bioaccesibility of heavy metals in biosolids.

    Science.gov (United States)

    Tongesayi, Tsanangurayi; Dasilva, Patricia; Dilger, Katharine; Hollingsworth, Tristan; Mooney, Melissa

    2011-01-01

    Cysteine residues on proteins have a high affinity for metals yet formulations used to determine bioaccessibility do not contain cysteine or thiol-containing molecules. As a result, we used a cysteine-simplified physiological-based extraction technique (SBET) and, the conventional glycine-SBET to determine bioaccesibility of selected heavy metals in biosolids and compared the data. We also determined speciation of the selected metals in the biosolids to assess further the health risk posed the use of biosolids as a soil amendment in agricultural soils. Samples, including a certified reference standard were analyzed using x-ray fluorescence and flame atomic absorption. Bioaccessibility was higher in cysteine-SBET than glycine-SBET, and regression data show that the two methods give different sets of results. We proposed a bioaccessibility model that involves cysteine and the hydrogen ion complementing each other to dissolve metals. The model also includes a three mode-bioavailability mechanism: absorption of free metal ions; ligand-mediated transport of metal ions from solution; and ligand-mediated transport of metal ions directly from the biosolids into the cell. Low pH in the gut increases bioaccessibility but reduces bioavailability due to protonation of receptor ligands. With the exception of Fe, bioaccessibility was directly correlated to the sequential extraction availability which followed the order: Mn(90.3 %)>Zn(50.3 %)>Cd(26.5 %)>Cu(24.9 %)>Fe(0.367 %). We calculated bioavailability from bioaccessibility using literature estimates of percent bioavailabilities. The order of abundance of the analyzed metals in the biosolids was as follows: Fe>Mn>Zn>Cu>Pb>Cd.

  16. The respective effects of soil heavy metal fractions by sequential extraction procedure and soil properties on the accumulation of heavy metals in rice grains and brassicas.

    Science.gov (United States)

    Xiao, Ling; Guan, Dongsheng; Peart, M R; Chen, Yujuan; Li, Qiqi

    2017-01-01

    This study was carried out to examine heavy metal accumulation in rice grains and brassicas and to identify the different controls, such as soil properties and soil heavy metal fractions obtained by the Community Bureau of Reference (BCR) sequential extraction, in their accumulation. In Guangdong Province, South China, rice grain and brassica samples, along with their rhizospheric soil, were collected from fields on the basis of distance downstream from electroplating factories, whose wastewater was used for irrigation. The results showed that long-term irrigation using the electroplating effluent has not only enriched the rhizospheric soil with Cd, Cr, Cu, and Zn but has also increased their mobility and bioavailability. The average concentrations of Cd and Cr in rice grains and brassicas from closest to the electroplating factories were significantly higher than those from the control areas. Results from hybrid redundancy analysis (hRDA) and redundancy analysis (RDA) showed that the BCR fractions of soil heavy metals could explain 29.0 and 46.5 % of total eigenvalue for heavy metal concentrations in rice grains and brassicas, respectively, while soil properties could only explain 11.1 and 33.4 %, respectively. This indicated that heavy metal fractions exerted more control upon their concentrations in rice grains and brassicas than soil properties. In terms of metal interaction, an increase of residual Zn in paddy soil or a decrease of acid soluble Cd in the brassica soil could enhance the accumulation of Cd, Cu, Cr, and Pb in both rice grains and brassicas, respectively, while the reducible or oxidizable Cd in soil could enhance the plants' accumulation of Cr and Pb. The RDA showed an inhibition effect of sand content and CFO on the accumulation of heavy metals in rice grains and brassicas. Moreover, multiple stepwise linear regression could offer prediction for Cd, Cu, Cr, and Zn concentrations in the two crops by soil heavy metal fractions and soil properties.

  17. 1H-NMR study of Na alginates extracted from Sargassum spp. in relation to metal biosorption.

    Science.gov (United States)

    Davis, Thomas A; Llanes, Francisco; Volesky, Bohumil; Diaz-Pulido, Guillermo; McCook, Laurence; Mucci, Alfonso

    2003-08-01

    The use of a number of species of marine brown algae in the implementation of bioremediation strategies for toxic heavy metals is being considered and evaluated. The biosorption capacity of these algae for heavy metals resides mainly in a group of linear polysaccharides known as alginates that occur as a gel in the algal thallus. The potential for selective metal binding by the biomass of two species of Sargassum was evaluated by 1H-NMR (nuclear magnetic resonance) following a high temperature, alkaline extraction and purification of their alginate polysaccharide. The alkaline extraction protocol applied to Sargassum fluitans and Sargassum siliquosum yielded alginate samples of low viscosity, suitable for direct acquisition of well-resolved spectra. Estimates of both the ratio of beta-D-mannopyranuronosyl (M) and alpha-L-gulopyranuronosyl (G) residues along the polymer chain and the frequencies of occurrence of diad uronic acid residue pairs were obtained. Guluronic acid (G) was the major component in all extracts and the GG diads accounted for more than 49% of the polymer diads. Whereas the performance of Sargassum spp. in the metal biosorption process is a function of both its alginate content and composition, the occurrence of "G-blocks" in both purified alginates and in the raw brown seaweed is critical because it results in a well-established selectivity for divalent ions, potentially increasing the commercial effectiveness of targeted biosorption as a means of remediation.

  18. Relationship between total concentration and dilute HCl extraction of heavy metals in sediments of harbors and coastal areas in Korea.

    Science.gov (United States)

    Choi, Ki Young; Kim, Suk Hyun; Chon, Hyo Taek

    2012-04-01

    Total concentrations of Cr, Ni, Cu, Zn, Cd and Pb in surface sediments were determined to investigate the regional trends of heavy metal contamination in 11 coastal areas in Korea. Enrichment factor (EF) of heavy metals was calculated by comparing the level of their regional background. The averages of EF values in study areas were 0.99 for Cr, 1.05 for Ni, 4.23 for Cu, 1.80 for Zn, 3.92 for Cd and 1.54 for Pb, respectively. Dilute HCl extractions were useful to deduce the anthropogenic sources of heavy metals and the 1 M HCl extractable fractions of each metal varied from 0.3 to 37.3% for Cr, 1.9 to 66.3% for Ni, 4.2 to 92.9% for Cu, 7.1 to 99.7% for Zn, 10.9 to 98.9% for Cd and 15.0 to 99.1% for Pb. Comparing 1 M HCl extractable fraction to total concentration, large portions of Cu, Zn, Cd and Pb were present as potentially bioavailable fractions from anthropogenic input and were significantly correlated with their EF values showing r > 0.68.

  19. Extractable Fractions of Metals in Sewage Sludges from Five Typical Urban Wastewater Treatment Plants of China

    Institute of Scientific and Technical Information of China (English)

    WANG Chao; LI Xiao-Chen; WANG Pei-Fang; ZOU Li-Min; MA Hai-Tao

    2006-01-01

    Metal content and bioavailability are often the limiting factors for application of sewage sludge in agricultural fields.Sewage sludge samples were collected from five typical urban wastewater treatment plants in China to investigate their contents and distribution of various chemical fractions of Cu, Zn, Ni, Cr, Pb and Mo by using the BCR (Community Bureau of Reference) sequential extraction procedure. The sludges contained considerable amounts of organic matter (31.8%-48.0%), total N (16.3-26.4 g kg-1) and total P (15.1-23.9 g kg-1), indicating high potential agricultural benefits of their practical applications. However, total Zn and Ni contents in the sludge exceeded the values permitted in China's control standards for pollutants in sludges from agricultural use (GB 4284-1984). The residual fraction was the predominant fraction for Mo, Ni and Cr, the oxidizable fraction was the primary fraction for Cu and Pb, and the exchangeable and reducible fractions were principal for Zn. The distribution of different chemical fractions among the sludge samples reflected differences in their physicochemical properties, especially pH. The sludge pH was negatively correlated with the percentages of reducible fraction of Cu and exchangeable fraction of Zn. The sludges from these plants might not be suitable for agricultural applications due to their high contents of Zn, Ni and Cr, as well as high potential of mobility and bioavailability of Zn.

  20. Synthesis, characterization and extraction studies of some metal (II) complexes containing (hydrazoneoxime and bis-acylhydrazone) moieties

    Science.gov (United States)

    Al-Ne'aimi, Mohammed Mahmmod; Al-Khuder, Mohammed Moudar

    2013-03-01

    In this study, diacetylmonoximebenzoylhydrazone (L1H2) and 1,4-diacetylbenzene bis(benzoyl hydrazone) (L2H2) were synthesized by the condensation of benzohydrazide with diacetyl monoxime and 1,4-diacetylbenzene, respectively. Complexes of these ligands with Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) inos were prepared with a metal:ligand ratio of 1:2 for L1H2 ligand, and 1:1 for L2H2 ligand. The ligands and their complexes were elucidated on the basis of elemental analyses CHN, AAS, FT-IR, 1H- and 13C NMR spectra, UV-vis spectra and magnetic susceptibility measurements. Results show the L1H2 ligand act as monoanionic O,N,N-tridentate and coordination takes place in the enol form through the oxime nitrogen, the imine nitrogen and the enolate oxygen atoms with a N4O2 donor environment, while the L2H2 ligand act as a dianionic O,N,N,O-tetradentate and coordination takes place in the enol form through the enolate oxygen and the azomethine nitrogen atoms with a N2O2 donor environment. These results are consistent with the formation of mononuclear metal (II) complexes [M(L1H)2], and binuclear polymeric metal (II) complexes [{M2(L2)}n]. The extraction ability of both ligands were examined in chloroform by the liquid-liquid extraction of selected transition metal [Co2+, Ni2+, Cu2+, Zn2+ and Pb2+] cations. The effects of pH and contact time on the percentage extraction of metal (II) ions were studied under the optimum extraction conditions. The (L1H2) ligand shows strong binding ability toward copper(II) and lead(II) ions, while the (L2H2) ligand shows strong binding ability toward nickel(II) and zinc(II) ions.

  1. Extraction of Channel Length Independent Series Resistance for Deeply Scaled Metal-Oxide-Semiconductor Field-Effect Transistors

    Science.gov (United States)

    Ma, Li-Juan; Ji, Xiao-Li; Chen, Yuan-Cong; Xia, Hao-Guang; Zhu, Chen-Xin; Guo, Qiang; Yan, Feng

    2014-09-01

    The recently developed four Rsd extraction methods from a single device, involving the constant-mobility method, the direct Id—Vgs method, the conductance method and the Y-function method, are evaluated on 32 nm n-channel metal-oxide-semiconductor field-effect transistors (nMOSFETs). It is found that Rsd achieved from the constant-mobility method exhibits the channel length independent characteristics. The L-dependent Rsd extracted from the other three methods is proven to be associated with the gate-voltage-induced mobility degradation in the extraction procedures. Based on L-dependent behaviors of Rsd, a new method is proposed for accurate series resistance extraction on deeply scaled MOSFETs.

  2. Enhanced extraction of heavy metals in the two-step process with the mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus.

    Science.gov (United States)

    Chang, Young-Cheol; Choi, DuBok; Kikuchi, Shintaro

    2012-01-01

    For biological extraction of heavy metals from chromated copper arsenate (CCA) treated wood, different bacteria were investigated. The extraction rates of heavy metals using Lactobacillusbulgaricus and Streptococcusthermophilus were highest. The chemical extraction rates were depended on the amounts of pyruvic acid and lactic acid. Especially, the extraction rates using mixed pyruvic acid and lactic acid were increased compared to those of sole one. They were also enhanced in the mixed culture of L. bulgaricus and S. thermophilus. To improve the extraction of CCA, a two-step processing procedure with the mixed culture of L. bulgaricus and S. thermophilus was conducted. A maximum of 93% of copper, 86.5% of chromium, and 97.8% of arsenic were extracted after 4 days. These results suggest that a two-step process with the mixed culture of L. bulgaricus and S. thermophilus is most effective to extract heavy metals from CCA treated wood. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Metal speciation of historic and new copper mine tailings from Repparfjorden, Northern Norway, before and after acid, base and electrodialytic extraction

    DEFF Research Database (Denmark)

    Pedersen, Kristine B.; Jensen, Pernille Erland; Ottosen, Lisbeth M.

    2017-01-01

    tailings. Substantial desorption (>40%) for both historic and new mine tailings occurred at pH values below 3 and above 12. These results combined with metal speciation, showing that the binding of Cu in the sediment changes around pH values 3 and 10, indicate potential for extraction of more Cu from...... the new mine tailings. Electrodialysis, based on applying an electric field of low intensity to extract metals from polluted soils/sediments, was designed for acidic and alkaline extraction, and in both cases more Cu was extracted than in the pure acid/base extractions, while maintaining low mobilisation...

  4. Sodium dodecyl sulfate coated poly (vinyl) chloride: an alternative support for solid phase extraction of some transition and heavy metals.

    Science.gov (United States)

    Marahel, Farzaneh; Ghaedi, Mehrorang; Shokrollahi, Ardeshir; Montazerozohori, Morteza; Davoodi, Shahnaz

    2009-01-01

    A simple and relatively fast approach for developing a solid phase extraction has been described and used for determination of trace quantities of some heavy and transition metal ions with sodium dodecyl sulfate (SDS)-coated poly vinyl chloride (PVC) modified with bis(2-hydroxyacetophenone)-1,4-butanediimine (BHABDI) ligand. The adsorbed ions were stripped from the solid phase by 10 mL of 3M nitric acid as eluent. The eluting solution was analyzed for metals content (cadmium, chromium, cobalt, copper, lead and zinc) by flame atomic absorption spectrometry (FAAS). The main factors such as pH, amount of ligand and PVC, amount and type of surfactant, and condition of eluting solutions on the sorption recovery of metal ions have been investigated in detail. The relative standard deviation was found in the range of 1.0-3.2% for 0.2 microg mL(-1)of metals ions. After optimization of the extraction condition and the instrumental parameters, a detection limit was found to be in the range of 1.2-3.1 microg L(-1), with enrichment factor of 50 was achieved. The method was successfully applied for the determination of these metals contents in real samples with satisfactory results.

  5. Secondary emission monitor (SEM) grids.

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    A great variety of Secondary Emission Monitors (SEM) are used all over the PS Complex. At other accelerators they are also called wire-grids, harps, etc. They are used to measure beam density profiles (from which beam size and emittance can be derived) in single-pass locations (not on circulating beams). Top left: two individual wire-planes. Top right: a combination of a horizontal and a vertical wire plane. Bottom left: a ribbon grid in its frame, with connecting wires. Bottom right: a SEM-grid with its insertion/retraction mechanism.

  6. Studies on the extraction and determination of metal salts with isobutyl methyl ketone-XIV Extraction of gold.

    Science.gov (United States)

    Ichinose, N

    1971-01-01

    The isobutyl methyl ketone extraction of gold(III) from hydrochloric acid or various mixtures of hydrochloric and other mineral acids was studied as a function of the gold concentration and the acid concentration. Gold (initial concentration up to 5 x 10(-3)M) was quantitatively extracted (99%) from 3-5M hydrochloric acid. Addition of nitric acid in 1-5M concentration and sulphuric or perchloric acid in 1-3N concentration to the 1-5M hydrochloric acid solutions used had no effect.

  7. Fabrication of metal-organic frameworks and graphite oxide hybrid composites for solid-phase extraction and preconcentration of luteolin.

    Science.gov (United States)

    Wang, Yang; Wu, Yichun; Ge, Huali; Chen, Huanhuan; Ye, Guiqin; Hu, Xiaoya

    2014-05-01

    A novel solid-phase extraction sorbent, metal-organic frameworks and graphite oxide hybrid composite, was prepared by a solvothermal technique. The morphology and properties of the resultant material were examined by Fourier transform infrared spectroscopy, X-ray diffraction and field emission scanning electron microscopy. To evaluate the extraction performance of the resultant sorbent, luteolin was chosen as a model analyte. The extraction conditions were optimized. Based on these, a convenient and efficient solid-phase extraction procedure for the determination of luteolin was established and the subsequent quantification step was performed by square wave anodic stripping voltammetry. Under the optimal conditions, the oxidation current increased linearly with increasing the concentration of luteolin in the range of 5.0 × 10(-9)-5.0 × 10(-7)molL(-1) with a correlation coefficient of 0.9983 and a detection limit of 7.9 × 10(-10)molL(-1). The relative standard deviation of seven successive scans was 4.20% for 5.0 × 10(-8)molL(-1) luteolin. This work not only proposes a useful method for sample pretreatment, but also reveals the great potential of metal-organic frameworks based hybrid materials as an excellent sorbent in solid-phase extraction.

  8. Influence of acid volatile sulfide and metal concentrations on metal bioavailability to marine invertebrates in contaminated sediments

    Science.gov (United States)

    Lee, B.-G.; Lee, J.-S.; Luoma, S.N.; Choi, H.J.; Koh, C.-H.

    2000-01-01

    An 18-day microcosm study was conducted to evaluate the influence of acid volatile sulfides (AVS) and metal additions on bioaccumulation from sediments of Cd, Ni, and Zn in two clams (Macoma balthica and Potamocorbula amurensis) and three marine polychaetes (Neanthes arenaceodentata, Heteromastus filiformis, and Spiophanes missionensis). Manipulation of AVS by oxidation of naturally anoxic sediments allowed use of metal concentrations typical of nature and evaluation of processes important to chronic metal exposure. A vertical sediment column similar to that often found in nature was used to facilitate realistic biological behavior. Results showed that AVS or porewater (PW) metals controlled bioaccumulation in only 2 of 15 metal-animal combinations. Bioaccumulation of all three metals by the bivalves was related significantly to metal concentrations extracted from sediments (SEM) but not to [SEM - AVS] or PW metals. SEM predominantly influenced bioaccumulation of Ni and Zn in N. arenaceodentata, but Cd bioaccumulation followed PW Cd concentrations. SEM controlled tissue concentrations of all three metals in H. filiformis and S. missionensis, with minor influences from metal-sulfide chemistry. Significant bioaccumulation occurred when SEM was only a small fraction of AVS in several treatments. Three factors appeared to contribute to the differences between these bioaccumulation results and the results from toxicity tests reported previously: differences in experimental design, dietary uptake, and biological attributes of the species, including mode and depth of feeding.An 18-day microcosm study was conducted to evaluate the influence of acid volatile sulfides (AVS) and metal additions on bioaccumulation from sediments of Cd, Ni, and Zn in two clams (Macoma balthica and Potamocorbula amurensis) and three marine polychaetes (Neanthes arenaceodentata, Heteromastus filiformis, and Spiophanes missionensis). Manipulation of AVS by oxidation of naturally anoxic sediments

  9. SEM: A Cultural Change Agent

    Science.gov (United States)

    Barnes, Bradley; Bourke, Brian

    2015-01-01

    The authors advance the concept that institutional culture is a purposeful framework by which to view SEM's utility, particularly as a cultural change agent. Through the connection of seemingly independent functions of performance and behavior, implications emerge that deepen the understanding of the influence of culture on performance outcomes…

  10. Simultaneous application of chemical oxidation and extraction processes is effective at remediating soil Co-contaminated with petroleum and heavy metals.

    Science.gov (United States)

    Yoo, Jong-Chan; Lee, Chadol; Lee, Jeung-Sun; Baek, Kitae

    2017-01-15

    Chemical extraction and oxidation processes to clean up heavy metals and hydrocarbon from soil have a higher remediation efficiency and take less time than other remediation processes. In batch extraction/oxidation process, 3% hydrogen peroxide (H2O2) and 0.1 M ethylenediaminetetraacetic acid (EDTA) could remove approximately 70% of the petroleum and 60% of the Cu and Pb in the soil, respectively. In particular, petroleum was effectively oxidized by H2O2 without addition of any catalysts through dissolution of Fe oxides in natural soils. Furthermore, heavy metals bound to Fe-Mn oxyhydroxides could be extracted by metal-EDTA as well as Fe-EDTA complexation due to the high affinity of EDTA for metals. However, the strong binding of Fe-EDTA inhibited the oxidation of petroleum in the extraction-oxidation sequential process because Fe was removed during the extraction process with EDTA. The oxidation-extraction sequential process did not significantly enhance the extraction of heavy metals from soil, because a small portion of heavy metals remained bound to organic matter. Overall, simultaneous application of oxidation and extraction processes resulted in highly efficient removal of both contaminants; this approach can be used to remove co-contaminants from soil in a short amount of time at a reasonable cost.

  11. Influence of EDDS on metal speciation in soil extracts: Measurement and mechanistic multicomponent modeling

    NARCIS (Netherlands)

    Koopmans, G.F.; Schenkeveld, W.D.C.; Song, J.; Luo, Y.; Japenga, J.; Temminghoff, E.J.M.

    2008-01-01

    The use of the [S,S]-isomer of EDDS to enhance phytoextraction has been proposed for the remediation of heavy metal contaminated soils. Speciation of metals in soil solution in the presence of EDDS and dissolved organic matter (DOM) received, however, almost no attention, whereas metal speciation pl

  12. Influence of EDDS on metal speciation in soil extracts: Measurement and mechanistic multicomponent modeling

    NARCIS (Netherlands)

    Koopmans, G.F.; Schenkeveld, W.D.C.; Song, J.; Luo, Y.; Japenga, J.; Temminghoff, E.J.M.

    2008-01-01

    The use of the [S,S]-isomer of EDDS to enhance phytoextraction has been proposed for the remediation of heavy metal contaminated soils. Speciation of metals in soil solution in the presence of EDDS and dissolved organic matter (DOM) received, however, almost no attention, whereas metal speciation pl

  13. Rapid Computer Aided Ligand Design and Screening of Precious Metal Extractants from TRUEX Raffinate with Experimental Validation

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Aurora Sue [Washington State Univ., Pullman, WA (United States); Wall, Nathalie [Washington State Univ., Pullman, WA (United States); Benny, Paul [Washington State Univ., Pullman, WA (United States)

    2015-11-16

    Rhodium is the most extensively used metal in catalytic applications; it occurs in mixed ores with platinum group metals (PGMs) in the earth’s crust in low concentrations (0.4 - 10 ppb). It is resistant to aerial oxidation and insoluble in all acids, including aqua regia, making classical purification methods time-consuming and inefficient. To ensure adequate purity, several precipitation and dissolution steps are necessary during separation. Low abundance, high demand, and extensive processing make rhodium the most expensive of all PGMs. From alternative sources, rhodium is also produced in sufficient quantities (0.47 kg per ton initial heavy metal (tIHM)) during the fission of U-235 in nuclear reactors along with other PGMs (i.e., Ag, Pd, Ru). A typical power water reactor operating with UO2 fuel after cooling can generate PGMs in quantities greater than found in the earth’s crust (0.5-2 kg/tIHM). This currently untapped supply of PGMs has the potential to yield $5,000-30,000/tIHM. It is estimated that by the year 2030, the amount of rhodium generated in reactors could exceed natural reserves. Typical SNF processing removes the heavier lanthanides and actinides and can leave PGMs at ambient temperatures in aqueous acidic (Cl⁻ or NO3⁻; pH < 1) solutions at various activities. While the retrieval of these precious metals from SNF would minimize waste generation and improve resource utilization, it has been difficult to achieve thus far. Two general strategies have been utilized to extract Rh(III) from chloride media: ion pairing and coordination complexation. Ion pairing mechanisms have been studied primarily with the tertiary and quaternary amines. Additionally, mixed mechanism extractions have been observed in which ion pairing is the initial mechanism, and longer extraction equilibrium time generated coordination complexes. Very few coordination complexation extraction ligands have been studied. This project approached this problem

  14. Assessment of bioavailable metals in the sediments of Yamuna flood plain using two different single extraction procedures

    Directory of Open Access Journals (Sweden)

    Sudesh Chaudhary

    2016-01-01

    Full Text Available Though flood plains are considered as most fertile areas across the world but they have come under severe stress due to the flow of untreated domestic and industrial effluents and therefore, needed attention for its characterisation and subsequent treatment plans. The sediment samples, collected at 0–15, 15–35 and 30–60 cm depth levels during pre and post monsoon season from east and west sides of the river Yamuna around the national capital region of Delhi, were assessed for bioavailability of lead (Pb, zinc (Zn and nickel (Ni using Ethylene Diamine Tetra Acetic Acid (EDTA and acetic acid. The average concentrations of Zn (25 ± 6 mg kg−1 and Pb (33 ± 6 mg kg−1 leached in EDTA were higher than that of in acetic acid (Zn: 22 ± 6 mg kg−1; Pb: 24 ± 5 mg kg−1 whereas Ni (24 ± 6 mg kg−1 leached more in acetic acid compared to EDTA (Ni: 21 ± 4 mg kg−1. The bioavailable concentrations of metals were comparable among 0–15 and 15–35 cm depth samples but decreased in 35–60 cm depth samples. The post monsoon samples contained lower amounts of total metals in comparison to pre-monsoon samples, an indication of washout/dilution effects of flood/high water flow during monsoon season. The percentages of metals, with reference to their respective total concentrations, in the flood plain sediments as extracted by EDTA were in the range of 14–47% for Pb, 17–54% for Zn, and 15–39% for Ni. The Zn, Ni and Pb were soluble in acetic acid in the range of 12–39%, 16.7–36.5% and 14–36%, respectively. The chemical nature of extracting agent affected the metal leaching. Acetic acid, a weak acid, extracted the metals that were present in exchangeable fraction and easily movable whereas EDTA, hexa-dentate complexing agent, extracted metals from carbonate and organically bound fractions of the sediment samples. This could result in metal accumulation in the floodplains, biomagnification, adverse

  15. Rapid microwave-assisted acid extraction of southern pine waste wood to remove metals from chromated copper arsenate (CCA) treatment

    Science.gov (United States)

    Chung-Yun Hse; Todd F. Shupe; Bin Yu

    2013-01-01

    Recovery of metals from chromated copper arsenate (CCA)-treated southern pine wood particles was investigated by extraction in a microwave reactor with binary combinations of acetic acid (AA), oxalic acid (OxA), and phosphoric acid (PhA). Use of OxA was not successful, as insoluble copper oxalate complexes impeded copper removal. The combination of OxA and AA also had...

  16. Quantitative determination, Metal analysis and Antiulcer evaluation of Methanol seeds extract of Citrullus lanatus Thunb (Cucurbitaceae) in Rats

    OpenAIRE

    Okunrobo O. Lucky; Uwaya O. John; Imafidon E. Kate; Osarumwense O. Peter; Omorodion E. Jude

    2012-01-01

    Objective: The use of herbs in treatment of diseases is gradually becoming universally accepted especially in non industrialized societies. Citrullus lanatus Thunb (Cucurbitaceae) commonly called water melon is widely consumed in this part of the world as food and medicine. This work was conducted to investigate the phytochemical composition, proximate and metal content analysis of the seed of Citrullus lanatus and to determine the antiulcer action of the methanol seed extract....

  17. Green Synthesis of Metal Nanoparticles via Natural Extracts: The Biogenic Nanoparticle Corona and Its Effects on Reactivity

    OpenAIRE

    COLAVITA, PAULA

    2015-01-01

    The optical and catalytic properties of metal nanoparticles have attracted significant attention for applications in a wide variety of fields, thus prompting interest in developing sustainable synthetic strategies that leverage the redox properties of natural compounds or extracts. Here, we investigate the surface chemistry of nanoparticles synthesized using coffee as a biogenic reductant. Building on our previously developed synthetic protocols for the preparation of silver and palladium nan...

  18. Metal Oxide Assisted Preparation of Core-Shell Beads with Dense Metal-Organic Framework Coatings for the Enhanced Extraction of Organic Pollutants.

    Science.gov (United States)

    Del Rio, Mateo; Palomino Cabello, Carlos; Gonzalez, Veronica; Maya, Fernando; Parra, Jose B; Cerdà, Victor; Turnes Palomino, Gemma

    2016-08-08

    Dense and homogeneous metal-organic framework (MOF) coatings on functional bead surfaces are easily prepared by using intermediate sacrificial metal oxide coatings containing the metal precursor of the MOF. Polystyrene (PS) beads are coated with a ZnO layer to give ZnO@PS core-shell beads. The ZnO@PS beads are reactive in the presence of 2-methylimidazole to transform part of the ZnO coating into a porous zeolitic imidazolate framework-8 (ZIF-8) external shell positioned above the internal ZnO precursor shell. The obtained ZIF-8@ZnO@PS beads can be easily packed in column format for flow-through applications, such as the solid-phase extraction of trace priority-listed environmental pollutants. The prepared material shows an excellent permeance to flow when packed as a column to give high enrichment factors, facile regeneration, and excellent reusability for the extraction of the pollutant bisphenol A. It also shows an outstanding performance for the simultaneous enrichment of mixtures of endocrine disrupting chemicals (bisphenol A, 4-tert-octylphenol and 4-n-nonylphenol), facilitating their analysis when present at very low levels (coatings.

  19. EXTRACT

    DEFF Research Database (Denmark)

    Pafilis, Evangelos; Buttigieg, Pier Luigi; Ferrell, Barbra

    2016-01-01

    The microbial and molecular ecology research communities have made substantial progress on developing standards for annotating samples with environment metadata. However, sample manual annotation is a highly labor intensive process and requires familiarity with the terminologies used. We have the...... and text-mining-assisted curation revealed that EXTRACT speeds up annotation by 15-25% and helps curators to detect terms that would otherwise have been missed.Database URL: https://extract.hcmr.gr/....

  20. Impact of Phosphate, Potassium, Yeast Extract, and Trace Metals on Chitosan and Metabolite Production by Mucor indicus.

    Science.gov (United States)

    Safaei, Zahra; Karimi, Keikhosro; Zamani, Akram

    2016-08-30

    In this study the effects of phosphate, potassium, yeast extract, and trace metals on the growth of Mucor indicus and chitosan, chitin, and metabolite production by the fungus were investigated. Maximum yield of chitosan (0.32 g/g cell wall) was obtained in a phosphate-free medium. Reversely, cell growth and ethanol formation by the fungus were positively affected in the presence of phosphate. In a phosphate-free medium, the highest chitosan content (0.42 g/g cell wall) and cell growth (0.66 g/g sugar) were obtained at 2.5 g/L of KOH. Potassium concentration had no significant effect on ethanol and glycerol yields. The presence of trace metals significantly increased the chitosan yield at an optimal phosphate and potassium concentration (0.50 g/g cell wall). By contrast, production of ethanol by the fungus was negatively affected (0.33 g/g sugars). A remarkable increase in chitin and decrease in chitosan were observed in the absence of yeast extract and concentrations lower than 2 g/L. The maximum chitosan yield of 51% cell wall was obtained at 5 g/L of yeast extract when the medium contained no phosphate, 2.5 g/L KOH, and 1 mL/L trace metal solution.

  1. Metal: ATP characteristics of insulin- and epidermal growth factor-stimulated phosphorylation in detergent extracts of rat liver plasma membranes.

    Science.gov (United States)

    Uhing, R J; Exton, J H

    1986-09-01

    The metal: ATP characteristics of insulin- and epidermal growth factor-(EGF)-stimulated protein kinase activities were examined in Nonidet P40 extracts of rat liver plasma membranes. The two kinase activities were capable of utilizing either manganese or magnesium, although differences were observed. Insulin-stimulated 32P incorporation into an Mr 95 000 protein exhibited a higher affinity for ATP in the presence of manganese compared to magnesium. At 200 microM ATP, insulin stimulated 32P incorporation into the Mr 95 000 protein 3- to 5-fold after 5 min in the presence of either metal. At 1 mM ATP, insulin-stimulated 32P incorporation was significantly greater in the presence of magnesium. In contrast, EGF-stimulated 32P incorporation into an Mr 170 000 protein exhibited similar ATP dependencies in the presence of magnesium or manganese. Basal phosphorylation of the Mr 170 000 protein was 2- to 3-fold higher in the presence of manganese, however. Since the higher basal phosphorylation persisted after chromatography on wheat germ lectin-Sepharose, it may represent an inherent activity of the receptor kinase. In the presence of magnesium: ATP, low concentrations of manganese enhanced both insulin- and EGF-stimulated phosphorylation of angiotensin II suggesting involvement of a second metal binding site which regulates the kinase activity. The results presented show major differences in the metal: ATP properties of the two major hormonally regulated protein kinase activities observed in detergent-extracted liver membranes.

  2. Infrared spectra, Raman laser, XRD, DSC/TGA and SEM investigations on the preparations of selenium metal, (Sb2O3, Ga2O3, SnO and HgO) oxides and lead carbonate with pure grade using acetamide precursors

    Indian Academy of Sciences (India)

    Moamen S Refat; Khaled M Elsabawy

    2011-07-01

    Ga2O3, Se metal, SnO, Sb2O3, HgO and PbCO3 are formed upon the reaction of acetamide aqueous solutions with Ga(NO3)3, SeO2, SnCl2, SbCl3, HgCl2 and Pb(NO3)2, respectively, at 90°C. Different amorphous or crystalline phases can be obtained depending upon the experimental conditions (molar ratios, metal salts and temperature). The chemical mechanisms for the formations of this metal, oxides or carbonate are discussed and the X-ray diffraction, scanning electron microscopy (SEM) and atomic force microscope (AFM) are described. The type of metal ions plays an important role in the decomposition of acetamide, leading to the formation of solid stable (metal, oxides or carbonate), soluble and gases species. These new precursors are more stable preventing the rapid precipitation of metal, oxides or carbonate. Furthermore, this route allows the formation of pure compounds in solutions.

  3. Extraction procedure compared to attenuation model to assess heavy metals mobility in sediments from Sepetiba Bay, Rio de Janeiro; Procedimento de fracionamento comparado a modelo de atenuacao para a avaliacao de mobilidade de metais pesados em sedimentos da Baia de Sepetiba, Rio de Janeiro

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Andreza Portella

    2006-07-01

    Sepetiba bay, located about 60 km west of the metropolitan region of Rio de Janeiro city, has undergone notable development in the last decades, with the establishment of about 400 industrial plants in its basin, basically metallurgical, which release its industrial waste either straight into the bay or through local rivers. The Sepetiba harbor also brought up a lot of industrial investment in that area. This urban and industrial expansion caused several environmental impacts, mainly due to the presence of heavy metals and other potentially toxic substances present in the effluents discharged into the bay. This work aimed to assess heavy metal (Cd, Cu, Ni, Pb e Zn) contamination and mobility in sediments from Sepetiba bay. The acid-volatile sulfides (AVS) and the concentration of simultaneously extracted metals (SIGMA[SEM) were determined in 65 sediment samples from Sepetiba bay, representing the whole area. The results obtained showed that Cd, Cu, Pb and Zn presented higher concentrations in the northeastern area (mainly in the mouth of Guandu and Canal de Sao Francisco rivers), while the highest concentration of Ni were observed in the western region of the bay. The comparison between SEM concentrations with the Canadian Sediment Quality Guidelines (TEL and PEL) indicated that Cd and Zn presented values which may hazard to aquatic organisms (concentration levels above PEL); the elements Cu, Pb and Ni presented concentration levels below PEL, suggesting low probability of toxicological effects to the aquatic organisms. On the other hand, the ratio {sigma}[SEM]/[AVS] was below 1 in the northeastern region, indicating that, in spite of the high concentration of the analyzed metals in this area, they are trapped in the sediment, as sulfides. The total metal concentrations in the sediments were also determined and the same distribution pattern obtained for the SEM were observed, with high concentrations in the northeastern region of the bay, classifying the area as

  4. Multiple heavy metals extraction and recovery from hazardous electroplating sludge waste via ultrasonically enhanced two-stage acid leaching.

    Science.gov (United States)

    Li, Chuncheng; Xie, Fengchun; Ma, Yang; Cai, Tingting; Li, Haiying; Huang, Zhiyuan; Yuan, Gaoqing

    2010-06-15

    An ultrasonically enhanced two-stage acid leaching process on extracting and recovering multiple heavy metals from actual electroplating sludge was studied in lab tests. It provided an effective technique for separation of valuable metals (Cu, Ni and Zn) from less valuable metals (Fe and Cr) in electroplating sludge. The efficiency of the process had been measured with the leaching efficiencies and recovery rates of the metals. Enhanced by ultrasonic power, the first-stage acid leaching demonstrated leaching rates of 96.72%, 97.77%, 98.00%, 53.03%, and 0.44% for Cu, Ni, Zn, Cr, and Fe respectively, effectively separated half of Cr and almost all of Fe from mixed metals. The subsequent second-stage leaching achieved leaching rates of 75.03%, 81.05%, 81.39%, 1.02%, and 0% for Cu, Ni, Zn, Cr, and Fe that further separated Cu, Ni, and Zn from mixed metals. With the stabilized two-stage ultrasonically enhanced leaching, the resulting over all recovery rates of Cu, Ni, Zn, Cr and Fe from electroplating sludge could be achieved at 97.42%, 98.46%, 98.63%, 98.32% and 100% respectively, with Cr and Fe in solids and the rest of the metals in an aqueous solution discharged from the leaching system. The process performance parameters studied were pH, ultrasonic power, and contact time. The results were also confirmed in an industrial pilot-scale test, and same high metal recoveries were performed.

  5. Production of mono- and bimetallic nanoparticles of noble metals by pyrolysis of organic extracts on silicon dioxide

    Science.gov (United States)

    Serga, V.; Kulikova, L.; Cvetkov, A.; Krumina, A.; Kodols, M.; Chornaja, S.; Dubencovs, K.; Sproge, E.

    2013-12-01

    In the present work the influence of the tri-n-octylammonium (Oct3NH+) salt anion (PtCl62-, PdCl42-, AuCl4-) nature on the phase composition and mean size of crystallites of the extract pyrolysis products on the SiO2 nanopowder has been studied. The XRD phase analysis of the composites (metal loading 2.4 wt.%) made under the same conditions, at the pyrolysis of Pt- and Au-containing extracts has shown the formation of nanoparticles of Pt (dPt = 15 nm) and Au (dAu = 33 nm), respectively. The end-product of the pyrolysis of the Pd-containing extract has an admixture phase of PdO along with the main metal phase (dPd = 21 nm). At the preparation of bimetallic particles (Pt-Pd, Pt-Au, Pd-Au) on the SiO2 nanopowder it has been found that the nanoparticles of the PtPd alloy, Pt and Au or Pd and Au nanoparticles are the products of the thermal decomposition of two-component mixtures of extracts. The investigation of catalytic properties of the produced composites in the reaction of glycerol oxidation by molecular oxygen in alkaline aqueous solutions has shown that all bimetallic composites exhibit catalytic activity in contrast to monometallic ones.

  6. Determination of noble metals in biological samples by electrothermal vaporization inductively coupled plasma mass spectrometry, following cloud point extraction

    Science.gov (United States)

    Andreia Mesquita da Silva, Márcia; Lúcia Azzolin Frescura, Vera; José Curtius, Adilson

    2001-10-01

    A simple separation procedure for noble metals based on cloud point extraction is proposed. The analyte ions in aqueous acidic solution, obtained by the acid digestion of the samples, were complexed with O, O-diethyl-dithiophosphate and Triton X-114 was added as a non-ionic surfactant. By increasing the temperature up to the cloud point, a phase separation occurs, resulting in an aqueous phase and a surfactant-rich phase containing most of the analytes that were complexed. The metals in the surfactant-rich phase were determined by electrothermal vaporization inductively coupled plasma mass spectrometry. The extraction conditions as well as the instrumental parameters were optimized. Enrichment factors ranging from 7 (Rh) to 60 (Pt) and limits of detection from 0.6 (Pt) to 3.0 ng l -1 (Rh) were obtained in the digested samples. The extraction was not efficient for Ir. Among the reference materials analyzed in this work, only one (SRM 2670, urine) presented recommended values for Au and Pt. Due to the non-availability of adequate CRMs, accuracy was assessed by spiking known analyte amounts to the acid digests. Recoveries close to 100% were observed for all the studied elements but Ru. Poor agreement between found and recommended values was observed for non-digested urine sample, probably due to the carrier effect of co-extracted residual matrix components. However, good agreement was reached after urine acid mineralization.

  7. Integrated photooxidative extractive deep desulfurization using metal doped TiO2 and eutectic based ionic liquid

    Science.gov (United States)

    Zaid, Hayyiratul Fatimah Mohd; Kait, Chong Fai; Mutalib, Mohamed Ibrahim Abdul

    2016-11-01

    A series of metal doped TiO2 namely Fe/TiO2, Cu/TiO2 and Cu-Fe/TiO2 were synthesized and characterized, to be used as a photocatalyst in the integrated photooxidative extractive deep desulfurization for model oil (dodecane) and diesel fuel. The order of the photocatalytic activity was Cu-Fe/TiO2 followed by Cu/TiO2 and then Fe/TiO2. Cu-Fe/TiO2 was an effective photocatalyst for sulfur conversion at ambient atmospheric pressure. Hydrogen peroxide was used as the source of oxidant and eutectic-based ionic liquid as the extractant. Sulfur conversion in model oil reached 100%. Removal of sulfur from model oil was done by two times extraction with a removal of 97.06% in the first run and 2.94% in the second run.

  8. Fast assessment of bioaccessible metallic contamination in marine sediments.

    Science.gov (United States)

    Terán-Baamonde, J; Carlosena, A; Soto-Ferreiro, R M; Andrade, J M; Prada, D

    2017-09-07

    A fast (16min) procedure to assess the bioaccessible metallic fraction of Cd, Cr, Cu, Ni, Pb and Zn simultaneously extracted (SEM) from marine sediments plus an indirect approach to determine acid volatile sulfides (AVS) are presented. For the extraction process magnetic agitation was compared with ultrasonic stirring (using a bath and a probe), and several stirring times were assayed. The proposed SEM procedure uses an ultrasonic probe and 1mL of HCl. It dramatically minimizes the turnaround time and the residues. AVS were evaluated as the difference between the amounts of sulphur in the solid residue after the extraction and total sulphur in the original sample. These procedures are fast, easy to implement and cost-effective to assess the potential risk posed by metals in marine sediments. They were tested using several CRMs and applied to sediments from two Galician Rias (NW Spain); their SEM-AVS differences indicated no biological risk. Copyright © 2017. Published by Elsevier Ltd.

  9. A comparison of an optimised sequential extraction procedure and dilute acid leaching of elements in anoxic sediments, including the effects of oxidation on sediment metal partitioning.

    Science.gov (United States)

    Larner, Bronwyn L; Palmer, Anne S; Seen, Andrew J; Townsend, Ashley T

    2008-02-11

    The effect of oxidation of anoxic sediment upon the extraction of 13 elements (Cd, Sn, Sb, Pb, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As) using the optimised Community Bureau of Reference of the European Commission (BCR) sequential extraction procedure and a dilute acid partial extraction procedure (4h, 1 molL(-1) HCl) was investigated. Elements commonly associated with the sulfidic phase, Cd, Cu, Pb, Zn and Fe exhibited the most significant changes under the BCR sequential extraction procedure. Cd, Cu, Zn, and to a lesser extent Pb, were redistributed into the weak acid extractable fraction upon oxidation of the anoxic sediment and Fe was redistributed into the reducible fraction as expected, but an increase was also observed in the residual Fe. For the HCl partial extraction, sediments with moderate acid volatile sulfide (AVS) levels (1-100 micromolg(-1)) showed no significant difference in element partitioning following oxidation, whilst sediments containing high AVS levels (>100 micromolg(-1)) were significantly different with elevated concentrations of Cu and Sn noted in the partial extract following oxidation of the sediment. Comparison of the labile metals released using the BCR sequential extraction procedure (SigmaSteps 1-3) to labile metals extracted using the dilute HCl partial extraction showed that no method was consistently more aggressive than the other, with the HCl partial extraction extracting more Sn and Sb from the anoxic sediment than the BCR procedure, whilst the BCR procedure extracted more Cr, Co, Cu and As than the HCl extraction.

  10. Organically modified silica with pyrazole-3-carbaldehyde as a new sorbent for solid-liquid extraction of heavy metals.

    Science.gov (United States)

    Radi, Smaail; Tighadouini, Said; Bacquet, Maryse; Degoutin, Stéphanie; Cazier, Francine; Zaghrioui, Mustapha; Mabkhot, Yahia N

    2013-12-24

    A new chelating matrix, SiNP, has been prepared by immobilizing 1.5-dimethyl-1H-pyrazole-3-carbaldehyde on silica gel modified with 3-aminopropyl-trimethoxysilane. This new chelating material was well characterized by elemental analysis, FT-IR spectroscopy, cross polarization magic angle spinning solid state 13C-NMR, nitrogen adsorption-desorption isotherm, BET surface area, BJH pore size, and scanning electron microscopy (SEM). The new product exhibits good chemical and thermal stability as determined by thermogravimetry curves (TGA). The new prepared material was used as an adsorbent for the solid-phase extraction (SPE) of Pb(II), Cd(II), Cu(II) and Zn(II) from aqueous solutions using a batch method, prior to their determination by flame atomic adsorption spectrometry. The adsorption capacity was investigated using kinetics and pH effects. Common coexisting ions did not interfere with separation and determination.

  11. Automated CD-SEM metrology for efficient TD and HVM

    Science.gov (United States)

    Starikov, Alexander; Mulapudi, Satya P.

    2008-03-01

    CD-SEM is the metrology tool of choice for patterning process development and production process control. We can make these applications more efficient by extracting more information from each CD-SEM image. This enables direct monitors of key process parameters, such as lithography dose and focus, or predicting the outcome of processing, such as etched dimensions or electrical parameters. Automating CD-SEM recipes at the early stages of process development can accelerate technology characterization, segmentation of variance and process improvements. This leverages the engineering effort, reduces development costs and helps to manage the risks inherent in new technology. Automating CD-SEM for manufacturing enables efficient operations. Novel SEM Alarm Time Indicator (SATI) makes this task manageable. SATI pulls together data mining, trend charting of the key recipe and Operations (OPS) indicators, Pareto of OPS losses and inputs for root cause analysis. This approach proved natural to our FAB personnel. After minimal initial training, we applied new methods in 65nm FLASH manufacture. This resulted in significant lasting improvements of CD-SEM recipe robustness, portability and automation, increased CD-SEM capacity and MT productivity.

  12. Analysis of non-metallic inclusions in steel by SEM/EDS experiences with the technique as applied to the plain carbon steel Cf53 (1.1213); Analyse nichtmetallischer Einschluesse in Stahl mittels REM/EDS und Anwendung auf den unlegierten Kohlenstoffstahl Cf53 (1.1213)

    Energy Technology Data Exchange (ETDEWEB)

    Lietzau, Jens [GKN Driveline International GmbH, Lohmar (Germany). Research and Product Development Centre

    2010-12-15

    The SEM/EDS provides detailed information on the chemical nature of the non-metallic inclusions present in a steel. However, this information cannot be accepted uncritically. There can be positive and negative preparation artefacts and inclusions might be mis-classified because some elements are not or wrongly identified. Also, this detailed information comes at the cost of considerably longer measurement times than automated LM inclusion analyses require, since LM image acquisition is faster and no time is spent on EDS. (orig.)

  13. Effects of modified zeolite on the removal and stabilization of heavy metals in contaminated lake sediment using BCR sequential extraction.

    Science.gov (United States)

    Wen, Jia; Yi, Yuanjie; Zeng, Guangming

    2016-08-01

    Sediment can be applied on land as a soil conditioner. However, toxic substances such as heavy metals within the sediment often lead to soil contamination if no proper management is conducted prior to land application. In order to reduce the bioavailable portion of heavy metals such as Pb, Cu, Zn and Cd, zeolite as a kind of stabilizer was investigated on the effect of metal stabilization in sediment. Zeolite was firstly modified and screened to get the best condition for removal of heavy metals. Results showed that the granulated zeolite with NaCl conditioning had the highest CEC and metal sorption. Using BCR sequential extraction, the selected modified zeolite effectively stabilized Pb, Cu, Zn and Cd in sediment to different extents. It was most suitable for Cd stabilization by reducing its acid exchangeable fraction while increasing the contents of the reducible and residual fractions. Modified zeolite also immobilized Cu, Zn and Pb in sediment by enhancing one stable fraction while decreasing the acid exchangeable fraction.

  14. Speciation of heavy metals by modified BCR sequential extraction procedure in different depths of sediments from Sungai Buloh, Selangor, Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Nemati, Keivan, E-mail: keivan_nemati@yahoo.com [Environmental Research Group, Department of Chemistry, University of Malaya (UM), Kuala Lumpur 50603 (Malaysia); Bakar, Nor Kartini Abu; Abas, Mhd. Radzi; Sobhanzadeh, Elham [Environmental Research Group, Department of Chemistry, University of Malaya (UM), Kuala Lumpur 50603 (Malaysia)

    2011-08-15

    Highlights: {yields} A BCR sequential extraction procedure was applied for measurement of heavy metals in Sungai Buloh sediments in different depths. {yields} The amounts of CF and percentage of RAC was measured in this study too. {yields} Highest CF was obtained for Cd, Co, Pb and Zn in these samples. {yields} Zn at S3 and Cd at S3-S7 showed a high risk for the sediment samples. There were no elements of very high risk conditions in the selected samples. - Abstract: The sequential extraction procedure proposed by the European Standard, Measurements and Testing (SM and T) program, formerly the Community Bureau of Reference (BCR), was applied for partitioning of heavy metals (HMs) in river sediments collected along the course of Sungai Buloh and the Straits of Malacca in Selangor, Malaysia. Eight elements (V, Pb, Cd, Cr, Co, Ni, Cu and Zn) from seven stations (S1-S7) and at different depths were analyzed using the modified BCR Sequential Extraction Procedure (SEP) in combination with ICP-MS to obtain the metal distribution patterns in this region. The results showed that heavy metal contaminations at S2 and S3 was more severe than at other sampling sites, especially for Zn, Cu, Ni and Pb. Nevertheless, the element concentrations from top to bottom layers decreased predominantly. The samples from the Straits of Malacca (S4-S7) the highest contamination factors obtained were for Co, Zn and Pb while the lowest were found for V and Cr, similar to Sungai Buloh sediments. The sediments showed a low risk for V, Cr, Cu and Pb with RAC values of less than 10%, but medium risk for Co, Zn (except S3), Cd at S1 and S2 and Ni at S1, S3 and S5. Zn at S3 and Cd at S3-S7 showed high risk to our sediment samples. There is not any element of very high risk conditions in the selected samples.

  15. Quantitative determination, Metal analysis and Antiulcer evaluation of Methanol seeds extract of Citrullus lanatus Thunb (Cucurbitaceae) in Rats

    Institute of Scientific and Technical Information of China (English)

    Okunrobo O Lucky; Uwaya O John; Imafidon E Kate; Osarumwense O Peter; Omorodion E Jude

    2012-01-01

    Objective: The use of herbs in treatment of diseases is gradually becoming universally accepted especially in non industrialized societies. Citrullus lanatus Thunb (Cucurbitaceae) commonly called water melon is widely consumed in this part of the world as food and medicine. This work was conducted to investigate the phytochemical composition, proximate and metal content analysis of the seed of Citrullus lanatus and to determine the antiulcer action of the methanol seed extract. Methods: Phytochemical screening, proximate and metal content analysis was done using the standard procedures and the antiulcer activity was evaluated against acetylsalicylic acid-induced ulcers. Results: The results revealed the presence of the following phytochemicals;flavonoids, saponins, tannins, alkaloids, glycosides. Proximate analysis indicated high concentration of carbohydrate, protein and fat while metal analysis showed the presence of sodium, calcium, zinc, magnesium at levels within the recommended dietary intake. Antiulcer potential of the extract against acetylsalicylic acid induced ulceration of gastric mucosa of Wister rats was evaluated at three doses (200mg/kg, 400mg/kg, and 800mg/kg). The ulcer parameters investigated included ulcer number, ulcer severity, ulcer index and percentage ulcer protection. The antiulcer activity was compared against ranitidine at 20mg/kg. The extract exhibited a dose related antiulcer activity with maximum activity at 800mg/kg (P<0.001). Conclusions: Proximate and metal content analysis of the seeds provides information that the consumption of the seeds ofCitrullus lanatus is safe. This present study also provides preliminary data for the first time that the seeds of Citrullus lanatus possesses antiulcer activity in animal model.

  16. Quantitative determination, Metal analysis and Antiulcer evaluation of Methanol seeds extract of Citrullus lanatus Thunb (Cucurbitaceae in Rats

    Directory of Open Access Journals (Sweden)

    Okunrobo O. Lucky

    2012-10-01

    Full Text Available Objective: The use of herbs in treatment of diseases is gradually becoming universally accepted especially in non industrialized societies. Citrullus lanatus Thunb (Cucurbitaceae commonly called water melon is widely consumed in this part of the world as food and medicine. This work was conducted to investigate the phytochemical composition, proximate and metal content analysis of the seed of Citrullus lanatus and to determine the antiulcer action of the methanol seed extract. Methods: Phytochemical screening, proximate and metal content analysis was done using the standard procedures and the antiulcer activity was evaluated against acetylsalicylic acid-induced ulcers. Results: The results revealed the presence of the following phytochemicals; flavonoids, saponins, tannins, alkaloids, glycosides. Proximate analysis indicated high concentration of carbohydrate, protein and fat while metal analysis showed the presence of sodium, calcium, zinc, magnesium at levels within the recommended dietary intake. Antiulcer potential of the extract against acetylsalicylic acid induced ulceration of gastric mucosa of Wister rats was evaluated at three doses (200mg/kg, 400mg/kg, and 800mg/kg. The ulcer parameters investigated included ulcer number, ulcer severity, ulcer index and percentage ulcer protection. The antiulcer activity was compared against ranitidine at 20mg/kg. The extract exhibited a dose related antiulcer activity with maximum activity at 800mg/kg (P<0.001. Conclusions: Proximate and metal content analysis of the seeds provides information that the consumption of the seeds of Citrullus lanatus is safe. This present study also provides preliminary data for the first time that the seeds of Citrullus lanatus possesses antiulcer activity in animal model.

  17. Certified reference material for the quality control of EDTA- and DTPA-extractable trace metal contents in calcareous soil (CRM 600)

    Energy Technology Data Exchange (ETDEWEB)

    Quevauviller, P. [European Commission, Standards, Measurements and Testing Programme, Brussels (Belgium); Lachica, M.; Barahona, E. [Estacion Experimental del Zaidin, Granada (Spain); Gomez, A. [Institut Nacional de Recherche Agronomique, Station d`Agronomie, Villenave d`Ornon (France); Rauret, G. [Universidad de Barcelona, Dept. de Quimica Analitica, Barcelona (Spain); Ure, A. [University of Strathclyde, Dept. of Pure and Applied Chemistry, Glasgow (United Kingdom); Muntau, H. [European Commission, Joint Research Centre, Environment Institute, Ispra (Italy)

    1998-03-01

    Single extraction tests are commonly used to study the eco-toxicity and mobility of metals in soils, e.g. to assess the bioavailable metal fraction (and thus to estimate the related phyto-toxic and nutritional deficiency effects) and the environmentally accessible trace metals upon disposal of e.g. sediment on to a soil (e.g. contamination of ground waters). However, the lack of uniformity in the different procedures does not allow the results to be compared worldwide nor the procedures to be validated. This paper describes the interlaboratory testing of EDTA- and DTPA-extraction procedures for soil analysis, followed by the preparation of a calcareous soil reference material (CRM 600), the homogeneity and stability studies and the analytical work performed for the certification of the EDTA- and DTPA- extractable contents of some trace metals (following the standardized extraction procedures). (orig.) With 2 figs., 7 tabs., 14 refs.

  18. Interpretation of heavy metal speciation in sequential extraction using geochemical modelling

    NARCIS (Netherlands)

    Cui, Yanshan; Weng, Liping

    2015-01-01

    Environmental context Heavy metal pollution is a worldwide environmental concern, and the risk depends not only on their total concentration, but also on their chemical speciation. Based on state-of-the-art geochemical modelling, we pinpoint the heavy metal pools approached by the widely used seq

  19. Extraction of oleuropein from olive leaves, in order to use as inhibitor against the corrosion of metals

    Directory of Open Access Journals (Sweden)

    EFROSINI KOKALARI (TELI

    2014-06-01

    Full Text Available Oleuropein is the most abundant phenolic compound in olive leaves. This compound has been extensively studied for human health benefits. In recent years oleuropein, is proved to be an efficient inhibitor against the corrosion of metals and alloys. The use of chemical inhibitors has been limited, because of the environmental threat. The increasing ecological awareness among scientists have led to the development of “green” alternatives to mitigate corrosion. It is very important to choose cheap and safety handled compounds to be used as corrosion inhibitors.The extract of oleuropein from olive leaves, represent a great inhibitive action about 93%, against the corrosion of carbon steel in acidic media. Oleuropein, a natural product of the secoiridoid group, is a heterosidic ester of elenolic deteracid and 3,4-dihydroxyphenylethanol, containing a molecule of glucose, the hydrolysis of which yields elenolic acid glucoside and hydroxytyrosol. Oleuropein from the olive leaves was obtained by alcoholic extraction in room temperature using microwave irradiation. The extract was stored at 4oC and in the dark. The product of extraction was analyzed with HPLC, and infrared (IR spectroscopy, in order to define it’s chemical structure. Also we defined the yield, density and molecular weight of the product. The product of extraction was oleuropein and we propose to use it as corrosion inhibitor.

  20. Weak acid extractable metals in Bramble Bay, Queensland, Australia: temporal behaviour, enrichment and source apportionment.

    Science.gov (United States)

    Brady, James P; Ayoko, Godwin A; Martens, Wayde N; Goonetilleke, Ashantha

    2015-02-15

    Sediment samples were taken from six sampling sites in Bramble Bay, Queensland, Australia between February and November in 2012. They were analysed for a range of heavy metals including Al, Fe, Mn, Ti, Ce, Th, U, V, Cr, Co, Ni, Cu, Zn, As, Cd, Sb, Te, Hg, Tl and Pb. Fraction analysis, Enrichment Factors and Principal Component Analysis-Absolute Principal Component Scores (PCA-APCS) were carried out in order to assess metal pollution, potential bioavailability and source apportionment. Cr and Ni exceeded the Australian Interim Sediment Quality Guidelines at some sampling sites, while Hg was found to be the most enriched metal. Fraction analysis identified increased weak acid soluble Hg and Cd during the sampling period. Source apportionment via PCA-APCS found four sources of metals pollution, namely, marine sediments, shipping, antifouling coatings and a mixed source. These sources need to be considered in any metal pollution control measure within Bramble Bay.

  1. SEM Investigation of Superheater Deposits from Biomass-Fired Boilers

    DEFF Research Database (Denmark)

    Jensen, Peter Arendt; Frandsen, Flemming; Hansen, Jørn

    2004-01-01

    , mature superheater deposit samples were extracted from two straw-fired boilers, Masnedø and Ensted, with fuel inputs of 33 MWth and 100 MWth, respectively. SEM (scanning electron microscopy) images and EDX (energy dispersive X-ray) analyses were performed on the deposit samples. Different strategies...

  2. An advanced study on the hydrometallurgical processing of waste computer printed circuit boards to extract their valuable content of metals.

    Science.gov (United States)

    Birloaga, Ionela; Coman, Vasile; Kopacek, Bernd; Vegliò, Francesco

    2014-12-01

    This study refers to two chemical leaching systems for the base and precious metals extraction from waste printed circuit boards (WPCBs); sulfuric acid with hydrogen peroxide have been used for the first group of metals, meantime thiourea with the ferric ion in sulfuric acid medium were employed for the second one. The cementation process with zinc, copper and iron metal powders was attempted for solutions purification. The effects of hydrogen peroxide volume in rapport with sulfuric acid concentration and temperature were evaluated for oxidative leaching process. 2M H2SO4 (98% w/v), 5% H2O2, 25 °C, 1/10 S/L ratio and 200 rpm were founded as optimal conditions for Cu extraction. Thiourea acid leaching process, performed on the solid filtrate obtained after three oxidative leaching steps, was carried out with 20 g/L of CS(NH2)2, 6g/L of Fe(3+), 0.5M H2SO4, The cross-leaching method was applied by reusing of thiourea liquid suspension and immersing 5 g/L of this reagent for each other experiment material of leaching. This procedure has lead to the doubling and, respectively, tripling, of gold and silver concentrations into solution. These results reveal a very efficient, promising and environmental friendly method for WPCBs processing.

  3. Speciation of heavy metals by modified BCR sequential extraction procedure in different depths of sediments from Sungai Buloh, Selangor, Malaysia.

    Science.gov (United States)

    Nemati, Keivan; Abu Bakar, Nor Kartini; Abas, Mhd Radzi; Sobhanzadeh, Elham

    2011-08-15

    The sequential extraction procedure proposed by the European Standard, Measurements and Testing (SM&T) program, formerly the Community Bureau of Reference (BCR), was applied for partitioning of heavy metals (HMs) in river sediments collected along the course of Sungai Buloh and the Straits of Malacca in Selangor, Malaysia. Eight elements (V, Pb, Cd, Cr, Co, Ni, Cu and Zn) from seven stations (S1-S7) and at different depths were analyzed using the modified BCR Sequential Extraction Procedure (SEP) in combination with ICP-MS to obtain the metal distribution patterns in this region. The results showed that heavy metal contaminations at S2 and S3 was more severe than at other sampling sites, especially for Zn, Cu, Ni and Pb. Nevertheless, the element concentrations from top to bottom layers decreased predominantly. The samples from the Straits of Malacca (S4-S7) the highest contamination factors obtained were for Co, Zn and Pb while the lowest were found for V and Cr, similar to Sungai Buloh sediments. The sediments showed a low risk for V, Cr, Cu and Pb with RAC values of less than 10%, but medium risk for Co, Zn (except S3), Cd at S1 and S2 and Ni at S1, S3 and S5. Zn at S3 and Cd at S3-S7 showed high risk to our sediment samples. There is not any element of very high risk conditions in the selected samples.

  4. International Conference on SEMS 2012

    CERN Document Server

    Liu, Chuang; Scientific explanation and methodology of science; SEMS 2012

    2014-01-01

    This volume contains the contributed papers of invitees to SEMS 2012 who have also given talks at the conference. The invitees are experts in philosophy of science and technology from Asia (besides China), Australia, Europe, Latin America, North America, as well as from within China. The papers in this volume represent the latest work of each researcher in his or her expertise; and as a result, they give a good representation of the cutting-edge researches in diverse areas in different parts of the world.

  5. Urban Biomining: Biological Extraction of Metals and Materials from Electronics Waste Using a Synthetic Biology Approach

    Science.gov (United States)

    Urbina-Navarrete, J.; Rothschild, L.

    2016-12-01

    End-of-life electronics waste (e-waste) containing toxic and valuable materials is a rapidly progressing human health and environmental issue. Using synthetic biology tools, we have developed a recycling method for e-waste. Our innovation is to use a recombinant version of a naturally-occurring silica-degrading enzyme to depolymerize the silica in metal- and glass- containing e-waste components, and subsequently, to use engineered bacterial surfaces to bind and separate metals from a solution. The bacteria with bound metals can then be used as "bio-ink" to print new circuits using a novel plasma jet electronics printing technology. Here, we present the results from our initial studies that focus on the specificity of metal-binding motifs for a cognate metal. The candidate motifs that show high affinity and specificity will be engineered into bacterial surfaces for downstream applications in biologically-mediated metal recycling. Since the chemistry and role of Cu in metalloproteins is relatively well-characterized, we are using Cu as a proxy to elucidate metal and biological ligand interactions with various metals in e-waste. We assess the binding parameters of 3 representative classes of Cu-binding motifs using isothermal titration calorimetry; 1) natural motifs found in metalloproteins, 2) consensus motifs, and 3) rationally designed peptides that are predicted, in silico, to bind Cu. Our results indicate that naturally-occurring motifs have relative high affinity and specificity for Cu (association constant for Cu Ka 104 M-1, Zn Ka 103 M-1) when competing ions are present in the aqueous milieu. However, motifs developed through rational design by applying quantum mechanical methods that take into account complexation energies of the elemental binding partners and molecular geometry of the cognate metal, not only show high affinity for the cognate metal (Cu Ka 106 M-1), but they show specificity and discrimination against other metal ions that would be

  6. Long-term field metal extraction by Pelargonium: phytoextraction efficiency in relation to plant maturity.

    Science.gov (United States)

    Shahid, Muhammad; Arshad, Muhammad; Kaemmerer, Michel; Pinelli, Eric; Probst, Anne; Baque, David; Pradere, Philippe; Dumat, Camille

    2012-01-01

    The long length of periods required for effective soil remediation via phytoextraction constitutes a weak point that reduces its industrial use. However, these calculated periods are mainly based on short-term and/or hydroponic controlled experiments. Moreover, only a few studies concern more than one metal, although soils are scarcely polluted by only one element. In this scientific context, the phytoextraction of metals and metalloids (Pb, Cd, Zn, Cu, and As) by Pelargonium was measured after a long-term field experiment. Both bulk and rhizosphere soils were analyzed in order to determine the mechanisms involved in soil-root transfer. First, a strong increase in lead phytoextraction was observed with plant maturity, significantly reducing the length of the period required for remediation. Rhizosphere Pb, Zn, Cu, Cd, and As accumulation was observed (compared to bulk soil), indicating metal mobilization by the plant, perhaps in relation to root activity. Moreover, metal phytoextraction and translocation were found to be a function of the metals' nature. These results, taken altogether, suggest that Pelargonium could be used as a multi-metal hyperaccumulator under multi-metal soil contamination conditions, and they also provide an interesting insight for improving field phytoextraction remediation in terms of the length of time required, promoting this biological technique.

  7. Analysis of heavy metals and fluoride in vegetation by extraction with concentrated mineral acids.

    Science.gov (United States)

    Johnson, M S

    1975-01-01

    A rapid potentiometric method for determining fluoride in vegetation is described. Recovery of flouride by extraction with concentrated mineral acids compares favourably with standard methods of analysis in terms of accuracy and precision. The procedure affords the additional advantage that several citations are also quantitatively extracted and may be determined directly in the acid digest by atomic absorption spectrophotometry.

  8. Effects of soil oven-drying on concentrations and speciation of trace metals and dissolved organic matter in soil solution extracts of sandy soils

    NARCIS (Netherlands)

    Koopmans, G.F.; Groenenberg, J.E.

    2011-01-01

    Weak salt extracts can be used to assess the availability of trace metals for leaching and uptake by soil organisms and plants in soil. Before extraction, the International Organization for Standardization recommends to dry soils in an oven at a temperature of 40 °C. Effects of soil oven-drying on

  9. Effects of soil oven-drying on concentrations and speciation of trace metals and dissolved organic matter in soil solution extracts of sandy soils

    NARCIS (Netherlands)

    Koopmans, G.F.; Groenenberg, J.E.

    2011-01-01

    Weak salt extracts can be used to assess the availability of trace metals for leaching and uptake by soil organisms and plants in soil. Before extraction, the International Organization for Standardization recommends to dry soils in an oven at a temperature of 40 °C. Effects of soil oven-drying on d

  10. Multi-element pre-concentration of heavy metal ions by solid phase extraction on Chromosorb 108

    Energy Technology Data Exchange (ETDEWEB)

    Tuzen, Mustafa [Gaziosmanpasa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat (Turkey); Soylak, Mustafa [Erciyes University, Faculty of Art and Science, Department of Chemistry, 38039 Kayseri (Turkey)]. E-mail: soylak@erciyes.edu.tr; Elci, Latif [Pamukkale University, Faculty of Art and Science, Department of Chemistry, 20020 Denizli (Turkey)

    2005-08-29

    A multi-element preconcentration procedure for solid phase extraction on Chromosorb 108 as bathocuproinedisulfonic acid chelates and flame atomic absorption spectrometric determinations of some heavy metal ions in environmental samples is proposed in the present work. The influences of analytical parameters including pH of the aqueous solution, amounts of reagents, flow rates of sample and eluent solutions, sample volume etc. on the quantitative recoveries of copper, cadmium, lead, zinc, manganese, iron, chromium, nickel and cobalt ions were investigated. The effects of concomitant ions on the retentions of the analytes were also examined. The presented preconcentration procedure was applied to the determination of metal ions in reference standard materials (NRCC-SLRS 4 Riverine Water, SRM 1515 Apple leaves and GBW 07605 Tea) and some real samples including tap and river water, red wine, rice, black tea and honey.

  11. Is there widespread metal contamination from in-situ bitumen extraction at Cold Lake, Alberta heavy oil field?

    Science.gov (United States)

    Skierszkan, Elliott K; Irvine, Graham; Doyle, James R; Kimpe, Linda E; Blais, Jules M

    2013-03-01

    The extraction of oil sands by in-situ methods in Alberta has expanded dramatically in the past two decades and will soon overtake surface mining as the dominant bitumen production process in the province. While concerns regarding regional metal emissions from oil sand mining and bitumen upgrading have arisen, there is a lack of information on emissions from the in-situ industry alone. Here we show using lake sediment records and regionally-distributed soil samples that in the absence of bitumen upgrading and surface mining, there has been no significant metal (As, Cd, Cu, Hg, Ni, Pb, V) enrichment from the Cold Lake in-situ oil field. Sediment records demonstrate post-industrial Cd, Hg and Pb enrichment beginning in the early Twentieth Century, which has leveled off or declined since the onset of commercial in-situ bitumen production at Cold Lake in 1985.

  12. Migration and transformation rule of heavy metals in sludge during hydrolysis for protein extraction.

    Science.gov (United States)

    Li, Yulong; Xue, Fei; Li, Jiebing; Xu, Shi Hong; Li, Dengxin

    2016-03-01

    The content and speciation of heavy metals can fundamentally affect the hydrolysis of sludge. This research study investigates the migration and transformation rule of heavy metals during the hydrolysis process by measuring the content of exchangeables (F1), bound to carbonates (F2), bound to Fe-Mn oxides (F3), bound to organic matter (F4), and residuals (F5) under different periods of time undergoing hydrolysis. The results show that the hydrolysis process generally stabilized Cu, Zn, Mn, Ni, Pb, Cr, and As by transforming the unstable states into structurally stable states. Such transformations and stabilization were primarily caused by the changes in local metal ion environment and bonding structure, oxidation of sulfides, pyrolyzation of organic matter, and evaporation of resulting volatile materials. An X-ray diffractometry (XRD) of the residuals conducted after hydrolysis indicated that hydrolysis did have a significant influence on the transportation and transformation of heavy metals.

  13. Heavy Metals Extraction and Analysis in Aquatic Ecosystems with Automated Techniques

    National Research Council Canada - National Science Library

    TEODOROF, L; NASTASE, C; ANUTI, I; STROE, M

    2009-01-01

    .... Sample preparation is one of the important problems in analytical process. The microwave digestion coupled with ICP MS measurements, for the heavy metals analysis is a very useful tools for the environmental samples.

  14. Effective Extraction of Heavy Metals from their Effluents Using Some Potential Ionic Liquids as Green Chemicals

    Directory of Open Access Journals (Sweden)

    A. Rajendran

    2011-01-01

    Full Text Available Synthesis of nine Task Specific Ionic liquids (TSILs, their characterization using 1H NMR spectral studies and other physical properties and potential applications in the removal of certain heavy metals such as Nickel, Iron, Zinc, Copper and Lead has been studied. The removal of these heavy metals from the industrial effluents / contaminated water bodies using these ionic liquids has been proved to be more successful than conventional methods such as precipitation, cementation, reverse osmosis, ion exchange and adsorption.

  15. Assessment of sediment quality based on acid-volatile sulfide and simultaneously extracted metals in heavily industrialized area of Asaluyeh, Persian Gulf: concentrations, spatial distributions, and sediment bioavailability/toxicity.

    Science.gov (United States)

    Arfaeinia, Hossein; Nabipour, Iraj; Ostovar, Afshin; Asadgol, Zahra; Abuee, Ehsan; Keshtkar, Mozhgan; Dobaradaran, Sina

    2016-05-01

    Sediment samples from the coastal area of Asaluyeh harbor were collected during autumn and spring 2015. The acid-volatile sulfide (AVS) and simultaneously extracted metals (SEMs) were measured to assess the sediment quality and potential ecological risks. The average concentrations (and relative standard deviation (RSD)) of AVS in the industrial sediments were 12.32 μmol/g (36.91) and 6.34 μmol/g (80.05) in autumn and spring, respectively, while in the urban area, these values were 0.44 μmol/g (123.50) and 0.31 μmol/g (160.0) in autumn and spring, respectively. The average concentrations of SEM (and RSD) in the industrial sediments were 15.02 μmol/g (14.38) and 12.34 μmol/g (20.65) in autumn and spring, respectively, while in the urban area, these values were 1.10 μmol/g (43.03) and 1.06 μmol/g (55.59) in autumn and spring, respectively. Zn was the predominant component (34.25-86.24 %) of SEM, while the corresponding value for Cd, much more toxic ingredient, was less than 1 %. Some of the coastal sediments in the harbor of Asaluyeh (20 and 47 % in autumn and spring, respectively) had expected adverse biological effects based on the suggested criterion by United States Environmental Protection Agency (USEPA), while most stations (80 and 53 % in autumn and spring, respectively) had uncertain adverse effects.

  16. Micro-solid-phase extraction of organochlorine pesticides using porous metal-organic framework MIL-101 as sorbent.

    Science.gov (United States)

    Huang, Zhenzhen; Lee, Hian Kee

    2015-07-03

    In this study, a metal-organic framework material, MIL-101, used as a micro-solid-phase extraction (μ-SPE) sorbent for efficient enrichment of five organochlorine pesticides (OCPs), including α-HCH, Aldrin, α-Chlordane, Dieldrin and p,p'-DDD from water samples, followed by gas chromatography-mass spectrometry, is reported. This study demonstrated a new application of MIL-101 using μ-SPE, an advantage of the latter being its ability to process complex aqueous matrices, due to the protection of the sorbent afforded by the hollow fiber membrane bag. Key factors affecting extraction efficiency were studied, including elution solvent, extraction and desorption time. Under the optimal extraction conditions, the calibration plots were linear from 0.05 to 50 ng/mL for α-HCH and p,p'-DDD, and 0.1 to 50 ng/mL for the other three analytes. The limits of detection were between 0.0025 and 0.016 ng/mL. The relative recoveries of the OCPs spiked into real water samples (at 5 ng/mL of each analyte) ranged from 87.6 to 98.6% with relative standard deviations of <10%.

  17. Evaluating the mobility of toxic metals in untreated industrial wastewater sludge using a BCR sequential extraction procedure and a leaching test.

    Science.gov (United States)

    Kazi, T G; Jamali, M K; Kazi, G H; Arain, M B; Afridi, H I; Siddiqui, A

    2005-09-01

    The distribution and speciation of toxic metals in industrial wastewater sludge (IWS) was investigated. In this work, the modified BCR three-stage sequential extraction procedure was applied to the fractionation of Cr Pb Ni, and Cd in untreated industrial wastewater sludge from industrial sites in Hyderabad (Pakistan). The extracts were analyzed using electrothermal atomic absorption spectrometry. The procedure was evaluated using a certified reference material for soil mixed with sewage sludge BCR 483. The results from the partitioning study indicate that more easily mobilized forms (acid exchangeable) of Cd were dominant. The oxidizable fraction was dominant for all four toxic metals. Metal recovery was good, with metal recovered through the extractant steps and the total metal determined after microwave digestion. Lixiviation tests (DIN 38414-S4) were used to evaluate the leaching of toxic species from IWS, and it was observed that levels of leachable toxic metals were low compared to the amount of metal extracted in the exchangeable fraction of the BCR protocol.

  18. Synthesis, Spectral Characterization, SEM, Antimicrobial, Antioxidative Activity Evaluation, DNA Binding and DNA Cleavage Investigation of Transition Metal(II) Complexes Derived from a tetradentate Schiff base bearing thiophene moiety.

    Science.gov (United States)

    Abdel Aziz, Ayman A; Seda, Sabry H

    2017-03-01

    A novel series of Co(II), Ni(II), Cu(II) and Zn(II) mononuclear complexes have been synthesized involving a potentially tetradentate Schiff base ligand, which was obtained by condensation of 2-aminophenol with 2,5-thiophene-dicarboxaldehyde. The complexes were synthesized via reflux reaction of methanolic solution of the appropriate Schiff base ligand with one equivalent of corresponding metal acetate salt. Based on different techniques including micro analysis, FT-IR, NMR, UV-Vis, ESR, ESI-mass and conductivity measurements, four-coordinated geometry was assigned for all complexes. Spectroscopic data have shown that, the reported Schiff base coordinated to metal ions as a dibasic tetradentate ligand through the phenolic oxygen and the azomethine nitrogen. The antimicrobial activities of the parent ligand and its complexes were investigated by using the agar disk diffusion method. Antioxidation properties of the novel complexes were investigated and it was found that all the complexes have good radical scavenging properties. The binding of complexes to calf thymus DNA (CT-DNA) was investigated by absorption, emission and viscosity measurements. Binding studies have shown that all the complexes interacted with CT-DNA via intercalation mode and the binding affinity varies with relative order as Cu(II) complex > Co(II) complex > Zn(II) complex > Ni(II) complex. Furthermore, DNA cleavage properties of the metal complexes were also investigated. The results suggested the possible utilization of novel complexes for pharmaceutical applications.

  19. Fungos micorrízicos no crescimento e na extração de metais pesados pela braquiária em solo contaminado Mycorrhizal fungi influence on brachiariagrass growth and heavy metal extraction in a contaminated soil

    Directory of Open Access Journals (Sweden)

    Silvana da Silva

    2006-12-01

    Full Text Available Avaliou-se, em casa de vegetação, a influência de 14 isolados de fungos micorrízicos arbusculares (FMA no crescimento e extração de Zn, Cd, Cu e Pb pela Brachiaria decumbens em solo contaminado. Foram utilizadas plantas com e sem FMA, em vasos com 0,92 kg de solo com (mg kg-1: Zn, 3.300; Cu, 60; Cd, 29; Pb, 73. Os isolados fúngicos tiveram efeitos diferenciados no crescimento e aumentaram a produção de matéria seca em 84%. Os teores de metais na planta foram elevados e apresentaram relação inversa com a produção de matéria seca. Verificou-se que os FMA não afetaram os teores de Pb, mas reduziram em 20, 28 e 63% os teores de Zn, Cd e Cu na parte aérea, respectivamente, e aumentaram os teores de Cu nas raízes em mais de 1.000%. Os FMA aumentaram a quantidade de metais extraídos do solo em 845, 142, 68 e 54% para Cu, Pb, Zn e Cd, respectivamente. Acaulospora spinosa, Acaulospora morrowiae-UFLA e Gigaspora gigantea aumentaram a extração simultânea dos quatro metais contaminantes. Os FMA, de acordo com a espécie, aumentam a capacidade da B. decumbens de extrair metais pesados do solo.The influence of 14 arbuscular mycorrhiza fungal isolates (AMF on brachiariagrass growth and extraction of Zn, Cd, Cu and Pb from a contaminated soil was evaluated in a greenhouse experiment. Mycorrhizal and nonmycorrhizal Brachiaria decumbens plants were grown in pots with 0.92 kg of soil containing (mg kg-1: Zn, 3,300; Cu, 60; Cd, 29; Pb, 73. The AMF increased dry matter yield in 84%. Plant heavy metal concentrations were high and were inversely related to dry matter yield. Isolates caused no effect on Pb, but reduced shoot Zn, Cd and Cu concentrations by 20, 28 and 63%, respectively. It was observed effect of mycorrhiza on Cu accumulation in roots (over 1,000%. Isolates enhanced the total amount of soil extracted metals by 845, 142, 68 and 54% for Cu, Pb, Zn and Cd, respectively. Only Acaulospora spinosa, Acaulospora morrowiae-UFLA and Gigaspora

  20. A structural equation model of soil metal bioavailability to earthworms: confronting causal theory and observations using a laboratory exposure to field-contaminated soils.

    Science.gov (United States)

    Beaumelle, Léa; Vile, Denis; Lamy, Isabelle; Vandenbulcke, Franck; Gimbert, Frédéric; Hedde, Mickaël

    2016-11-01

    Structural equation models (SEM) are increasingly used in ecology as multivariate analysis that can represent theoretical variables and address complex sets of hypotheses. Here we demonstrate the interest of SEM in ecotoxicology, more precisely to test the three-step concept of metal bioavailability to earthworms. The SEM modeled the three-step causal chain between environmental availability, environmental bioavailability and toxicological bioavailability. In the model, each step is an unmeasured (latent) variable reflected by several observed variables. In an exposure experiment designed specifically to test this SEM for Cd, Pb and Zn, Aporrectodea caliginosa was exposed to 31 agricultural field-contaminated soils. Chemical and biological measurements used included CaC12-extractable metal concentrations in soils, free ion concentration in soil solution as predicted by a geochemical model, dissolved metal concentration as predicted by a semi-mechanistic model, internal metal concentrations in total earthworms and in subcellular fractions, and several biomarkers. The observations verified the causal definition of Cd and Pb bioavailability in the SEM, but not for Zn. Several indicators consistently reflected the hypothetical causal definition and could thus be pertinent measurements of Cd and Pb bioavailability to earthworm in field-contaminated soils. SEM highlights that the metals present in the soil solution and easily extractable are not the main source of available metals for earthworms. This study further highlights SEM as a powerful tool that can handle natural ecosystem complexity, thus participating to the paradigm change in ecotoxicology from a bottom-up to a top-down approach.

  1. Comparison of single extraction procedures and the application of an index for the assessment of heavy metal bioavailability in river sediments.

    Science.gov (United States)

    Sakan, Sanja; Popović, Aleksandar; Škrivanj, Sandra; Sakan, Nenad; Đorđević, Dragana

    2016-11-01

    Metals in sediments are present in different chemical forms which affect their ability to transfer. The objective of this body of work was to compare different extraction methods for the bioavailability evaluation of some elements, such as Ba, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, V and Zn from Serbian river sediments. A bioavailability risk assessment index (BRAI) was used for the quantification of heavy metal bioavailability in the sediments. Actual and potential element availability was assessed by single extractions with mild (CaCl2 and CH3COONH4) and acidic (CH3COOH) extractants and complexing agents (EDTA). Aqua regia extraction was used for the determination of the pseudo-total element content in river sediments. In different single extraction tests, higher extraction of Cd, Cu, Zn and Pb was observed than for the other elements. The results of the single extraction tests revealed that there is a considerable chance of metal leaching from the sediments assessed in this study. When the BRAI was applied, the results showed a high risk of heavy metal bioavailability in Serbian river sediments.

  2. Land use changes and metal mobility: multi-approach study on tidal marsh restoration in a contaminated estuary.

    Science.gov (United States)

    Teuchies, Johannes; Singh, Gurmeet; Bervoets, Lieven; Meire, Patrick

    2013-04-01

    Inundation of formerly embanked areas in order to combine flood control and tidal marsh restoration will be applied increasingly. However, areas suitable for the implementation are often found to be contaminated. Re-inundation of metal contaminated soils can have consequences on total metal concentrations as well as metal mobility. In this study, metal mobility in a tidal marsh restoration project was evaluated based on the modified BCR sequential extraction method, concentrations of acid volatile sulfides (AVS) and simultaneously extracted metals (SEM) and metal concentrations in plants. The results obtained from the sequential extraction suggest an increase in metal mobility following inundation due to the reduction of Fe and Mn oxides and the subsequent release of associated metals. However, the differences in results between sequential extraction and [SEM-AVS] may indicate that redistribution of the metals to the mobile fraction can be caused by sample processing. High AVS concentrations in newly deposited sediments in the restored marsh may indicate that the formation of insoluble metal-sulfide complexes will reduce metal mobility on the longer term. Processes following inundation of metal contaminated land are complex and different conditions prevailing in other sites or estuaries can result in different behavior of the trace metals. More in situ research is needed to get a better insight in the risks involved.

  3. Assessment of heavy metal pollution in sediments from Xiangjiang River (China) using sequential extraction and lead isotope analysis

    Institute of Scientific and Technical Information of China (English)

    蒋博峰; 孙卫玲

    2014-01-01

    The heavy metal (such as Cr, Ni, Cu, Cd, Pb, and Zn) concentration, speciation, and pollution source in 43 sediment samples from the Xiangjiang River were investigated using sequential extraction combined with Pb isotope analysis. Cu, Cd, Pb, and Zn concentrations are higher than their background values, while Cr and Ni concentrations are close to those. Sequential extraction demonstrates that heavy metals have different fractions, showing different bioavailabilities. Thew(206Pb)/w(207Pb) ratio increases with decreasing bioavailability in the order of exchangeable

  4. Metal ion determination by flame atomic absorption spectrometry through reagentless coacervate phase separation-extraction into lamellar vesicles.

    Science.gov (United States)

    Giokas, Dimosthenis L; Tsogas, George Z; Vlessidis, Athanasios G; Karayannis, Miltiades I

    2004-03-01

    The phase separation of lamellar vesicles of anionic surfactants in aqueous solutions and its application as a novel liquid coacervate extraction procedure was examined. Solutions of lauric acid sodium salt separate into two phases in the presence of alkaline earth metals and a water miscible cosurfactant. It is proven that the surfactant phase is built of a perplexed network of multilamellar vesicles consisting of densely packed bilayers. Several factors affecting the formation of this new phase as well as its analytical utility in the preconcentration of metallic ions were assessed on the basis of better exploitation of this new nonspecific extraction technique. In essence, although the procedure to arrive at the optimum conditions seems laborious, the delivered method is straightforward, alleviating the requirement for prereaction with a complexing agent and highly reproducible under the optimum experimental conditions. As an analytical demonstration, the method was successfully applied to the determination of Cd(2+) and Zn(2+) in natural waters. Recoveries were higher than 95%, and detection limits as low as 3 microg L(-)(1) were accomplished by preconcentrating only 10 mL of sample volume in the presence of 0.45% (w/v) anionic surfactant.

  5. EXTRACTION OF COPPER FROM LEACH LIQUOR OF METALLIC COMPONENT IN DISCARDED CELL PHONE BY CYANEX® 272

    Directory of Open Access Journals (Sweden)

    ALAFARA A. BABA

    2016-06-01

    Full Text Available Discarded cell phones contribute significantly to the amount of electronic waste generation whilst some of its components are toxic and recoverable. Also, due to the increasing demand for Cu(II in building/construction, electrical and as chemical tool in freshwater, it is imperative to develop low cost and ecofriendly technique as a substitute for the conventional treatments such as reduction-roasting route at elevated temperatures. In the present study, the hydrometallurgical operations involving leaching, solvent extraction and precipitation for the recovery of Cu(II by Cyanex® 272 in kerosene was examined. Various parameters affecting the extraction of Cu(II such as pH, extractant concentration and phase ratio were optimized. At optimal conditions, about 96.3 % Cu(II was extracted into the organic phase by 0.2 mol/L Cyanex® 272 at equilibrium pH 5.0 and aqueous to organic phase ratio 1:1. The stripping of the loaded organic was carried out by 0.1 mol/L HCl solution and stripping efficiency of 98 % was obtained. By McCabe Thiele diagram, four stages are required for complete extraction of Cu(II.

  6. Influence of seaweed extract as an organic fertilizer on the growth and yield ofArachis hypogeaL. and their elemental composition usingSEM-EnergyDispersiveSpectroscopic analysis

    Institute of Scientific and Technical Information of China (English)

    G. Ganapathy Selvam; K. Sivakumar

    2014-01-01

    Objective:To investigate the effect ofSeaweedLiquidFertilizer(SLF) of the red seaweedHypnea musciformis(Wulfen)Lamouroux(H. musciformis). on the growth, biochemical and pigment characteristics ofArachis hypogea(A. hypogea).Methods:Experiments were conducted on ground nut to study the potential red alga ofH. musciformis as a biofertilizer.The seeds were sown in soil andSLF were added to soil bed in five different concentrations separately(1%,2%, 4%,6% and8% w/v).Results:The2% concentration of water extract showed better results of growth parameters, biochemical and pigments constitutions.Among the different concentrations ofSLF investigated, the plants that received with2%SLF showed maximum germination percentage, fresh weight, dry weight, root and shoot length, number of branches, leaf area, root nodules and content of total chlorophyll, chlorophyll a and b, protein, carbohydrate and lipid were observed at2% concentration ofSLF.The leaf of2%SLF treated A. hypogea has subjected toScanningElectronMicroscopy withEnergyDispersive spectroscopic analysis, it revealed that the presence of ten elements in the following order:Ca>P>N>Na>K>Mg>Mn>S>Fe>Zn in treated andCa>N>P>Na>Mg>Mn>K>Zn>S>Fe in control plant.The data generated from study reveal that SLF ofH. musciformiscould be used as foliar spray at low concentration of2% to maximize the growth and yield of A. hypogeaand also increase the number of stomata in the leaf.Conclusion:It is suggested that there are considerable gains to be made in increasing yield and stabilizing the yield in environments characterized by terminal requirement for organic and by shortening crop duration nutrient management appear promising.

  7. Fractionation of metals by sequential extraction procedures (BCR and Tessier) in soil exposed to fire of wide temperature range

    Science.gov (United States)

    Fajkovic, Hana; Rončević, Sanda; Nemet, Ivan; Prohić, Esad; Leontić-Vazdar, Dana

    2017-04-01

    Forest fire presents serious problem, especially in Mediterranean Region. Effects of fire are numerous, from climate change and deforestation to loss of soil organic matter and changes in soil properties. One of the effects, not well documented, is possible redistribution and/or remobilisation of pollutants previously deposited in the soil, due to the new physical and chemical soil properties and changes in equilibrium conditions. For understanding and predicting possible redistribution and/or remobilisation of potential pollutants from soil, affected by fire different in temperature, several laboratory investigations were carried out. To evaluate the influence of organic matter on soil under fire, three soil samples were analysed and compared: (a) the one with added coniferous organic matter; (b) deciduous organic matter (b) and (c) soil without additional organic matter. Type of organic matter is closely related to pH of soil, as pH is influencing the mobility of some pollutants, e.g. metals. For that reason pH was also measured through all experimental steps. Each of mentioned soil samples (a, b and c) were heated at 1+3 different temperatures (25°C, 200°C, 500°C and 850°C). After heating, whereby fire effect on soil was simulated, samples were analysed by BCR protocol with the addition of a first step of sequential extraction procedure by Tessier and analysis of residual by aqua regia. Element fractionation of heavy metals by this procedure was used to determine the amounts of selected elements (Al, Cd, Cr, Co, Cu, Fe, Mn, Ni, Pb and Zn). Selected metal concentrations were determined using inductively coupled plasma atomic emission spectrometer. Further on, loss of organic matter was calculated after each heating procedure as well as the mineral composition. The mineral composition was determined using an X-ray diffraction. From obtained results, it can be concluded that temperature has an influence on concentration of elements in specific step of

  8. Synthesis and characterization of metallic nanoparticles impregnated onto activated carbon using leaf extract of Mukia maderasapatna: Evaluation of antimicrobial activities.

    Science.gov (United States)

    Saravanan, A; Kumar, P Senthil; Karthiga Devi, G; Arumugam, T

    2016-08-01

    In the present research, in vitro antimicrobial activity of metallic nanoparticles impregnated on activated carbon (MNPI-AC) was investigated. Activated carbon (AC) was successfully prepared from Fishtail palm Caryota urens seeds by using two surface modification process (i) sulphuric acid treated Caryota urens seeds (SMCUS) (ii) ultrasonic assisted Caryota urens seeds (UACUS). Mukia maderasapatna plant extract was used as reducing agent for the synthesis of metallic nanoparticles. The characterization studies of MNPI - AC were performed by using a UV-visible spectrophotometer and Fourier Transform Infrared Spectroscopic (FT-IR) analyses. Different active functional groups were identified by FTIR studies which were responsible for impregnation of metallic nanoparticles on a surface of AC. The antimicrobial activity of MNPI - AC was examined against four bacterial strains: 2 g positive (Staphylococcus aureus and Staphylococcus epidermidis) and 2 g negative (Pseudomonas aeruginosa and Escherichia coli) and one fungal strain (Candida albicans). Among different MNPs, Pb-AC (UACUS) shows that higher zone of inhibition. These results in the literature showed that MNPI - AC are to be effective for deactivation and inactivation of microbes in an efficient manner. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Study of the antimicrobial activity of metal complexes and their ligands through bioassays applied to plant extracts

    Directory of Open Access Journals (Sweden)

    Antonio F. Santos

    2014-06-01

    Full Text Available The appearance of resistant bacteria was found to reduce the efficiency of antimicrobial therapies with the current antibiotics, thereby increasing the need for more efficient drugs for the treatment of infections. Several studies have demonstrated an increase in antimicrobial activity following the interaction of several compounds with metal ions. The present study used a methodology adapted for antimicrobial bioassays using plant extracts, in compliance with the standards of the Clinical and Laboratory Standards Institute against Gram-positive and Gram-negative bacteria. The results obtained were considered appropriate for determining MIC, MBC as for performing antimicrobial sensitivity testing with good efficiency and reproducibility. The bacteriaPseudomonas fluorescens exhibited high sensitivity to the tested compounds, being efficient to evaluate the antibacterial activity. The bioassays with the metal complexes of flavonoid quercetin and Ga(III ions, and synthetic ligand H2bbppd and Cu(II ions showed a greater inhibitory effect than their individual ligands, thus, the addition indicated an increase in the antimicrobial activity after the coordination. Both metal complexes exhibit good antimicrobial performances, such as low minimum inhibitory concentration (MIC ≤ 250 µg/ml, bactericidal effect and a broad activity spectrum, which qualify these compounds as suitable candidates to the next step of drugs fabrication. Nevertheless, further studies on the mechanism of growth inhibition and toxicity are needed, in order to evaluate the potential of therapeutic application.

  10. Chemical separation and ICP-AES determination of 22 metallic elements in U and Pu matrices using cyanex-923 extractant and studies on stripping of U and Pu.

    Science.gov (United States)

    Argekar, A A; Kulkarni, M J; Mathur, J N; Page, A G

    2002-03-11

    Comprehensive studies have been carried out on the extraction behavior of uranium and plutonium matrices using cyanex-923 extractant. The near total extraction of U/Pu and quantitative separation of 22 metallic elements at trace levels has been established using inductively coupled plasma-atomic emission spectrometry (ICP-AES). The studies carried out on back extraction of U/Pu from organic phase have established the near total recovery of these matrices into the aqueous phase using 1 M Na(2)CO(3) and saturated oxalic acid, respectively.

  11. Metal-organic framework mixed-matrix disks: Versatile supports for automated solid-phase extraction prior to chromatographic separation.

    Science.gov (United States)

    Ghani, Milad; Font Picó, Maria Francesca; Salehinia, Shima; Palomino Cabello, Carlos; Maya, Fernando; Berlier, Gloria; Saraji, Mohammad; Cerdà, Víctor; Turnes Palomino, Gemma

    2017-03-10

    We present for the first time the application of metal-organic framework (MOF) mixed-matrix disks (MMD) for the automated flow-through solid-phase extraction (SPE) of environmental pollutants. Zirconium terephthalate UiO-66 and UiO-66-NH2 MOFs with different size (90, 200 and 300nm) have been incorporated into mechanically stable polyvinylidene difluoride (PVDF) disks. The performance of the MOF-MMDs for automated SPE of seven substituted phenols prior to HPLC analysis has been evaluated using the sequential injection analysis technique. MOF-MMDs enabled the simultaneous extraction of phenols with the concomitant size exclusion of molecules of larger size. The best extraction performance was obtained using a MOF-MMD containing 90nm UiO-66-NH2 crystals. Using the selected MOF-MMD, detection limits ranging from 0.1 to 0.2μgL(-1) were obtained. Relative standard deviations ranged from 3.9 to 5.3% intra-day, and 4.7-5.7% inter-day. Membrane batch-to-batch reproducibility was from 5.2 to 6.4%. Three different groundwater samples were analyzed with the proposed method using MOF-MMDs, obtaining recoveries ranging from 90 to 98% for all tested analytes.

  12. Influence of the selective EDTA derivative phenyldiaminetetraacetic acid on the speciation and extraction of heavy metals from a contaminated soil.

    Science.gov (United States)

    Zhang, Tao; Wei, Hang; Yang, Xiu-Hong; Xia, Bing; Liu, Jun-Min; Su, Cheng-Yong; Qiu, Rong-Liang

    2014-08-01

    The development of more selective chelators for the washing of heavy metal contaminated soil is desirable in order to avoid excessive dissolution of soil minerals. Speciation and mobility of Cu, Zn, Pb, and Ni in a contaminated soil washed with phenyldiaminetetraacetic acid (PDTA), a derivative of EDTA, were investigated by batch leaching test using a range of soil washing conditions followed by sequential extraction. With appropriate washing conditions, PDTA significantly enhanced extraction of Cu from the contaminated soil. The primary mechanisms of Cu extraction by PDTA were complexation-promoted dissolution of soil Cu and increased dissolution of soil organic matter (SOM). PDTA showed high selectivity for Cu(II) over soil component cations (Ca(II), Mg(II), Fe(III), Mn(II), Al(III)), especially at lower liquid-to-soil ratios under PDTA deficiency, thus avoiding unwanted dissolution of soil minerals during the soil washing process which can degrade soil structure and interfere with future land use. PDTA-enhanced soil washing increased the exchangeable fractions of Cu, Zn, and Pb and decreased their residual fractions, compared to their levels in unwashed soil.

  13. Miniplant technology for heavy-metal precipitation by means of reactive extraction processes; Miniplanttechnik zur Schwermetallentfernung mittels reaktiver Extraktionsverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Bart, H.J.; Schoeneberger, A. [Kaiserslautern Univ. (Germany). Lehrstuhl Thermische Verfahrenstechnik

    1999-07-01

    The development of novel techniques and their apparatus nowadays involves increasingly laboratory-scale technical systems (miniplant) in combination with simulation programs. For the precipitation of pollutants, especially heavy metals, from watery solutions, selective-action liquid ion exchangers are excellently suited, which are used in systems of various technical designs. The paper discusses their potential of application, the advantages and shortcomings of liquid-liquid extraction (counter-flow technique), of non-dispersive extraction (membrane technique) and of extractant-impregnated resins (packed-bed process) as well as their integration in miniplant systems. (orig.) [German] Bei der Entwicklung neuer Verfahren und bei deren apparativer Umsetzung werden heutzutage verstaerkt Anlagen im Labormassstab (Miniplant) in Kombination mit Simulationsprogrammen eingesetzt. Zur Entfernung von Schadstoffen, insbesondere Schwermetallen, aus waessrigen Loesungen eignen sich hervorragend selektiv wirkende fluessige Ionentauscher, die in unterschiedlicher Apparatetechnik zur Anwendung kommen. Das Einsatzpotential sowie Vor- und Nachteile der fluessig-fluessig Extraktion (Gegenstromverfahren), der nicht-dispersiven Extraktion (Membranverfahren), von extraktionsmittel-impraegnierten Harzen (Festbettverfahren) und die Einbindung in Miniplants werden diskutiert. (orig.)

  14. Thermo-responsive metal-chelating surfactants. Properties and use in cloud point extraction of uranyl nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Prevost, S.; Coulombeau, H. [CEA, IRAMIS, SCM, LIONS, 91 - Gif-sur-Yvette (France); Univ. de Versailles St Quentin en Y. Institut Lavoisier UMR CNRS 8180 (France); Baczko, K.; Larpent, C. [Univ. de Versailles St Quentin en Y. Institut Lavoisier UMR CNRS 8180 (France); Berthon, L.; Zorz, N. [CEA/DEN/DRCP/SCPS/LCSE, 30 - Bagnols sur Ceze (France); Desvaux, H.; Testard, F. [CEA, IRAMIS, SCM, LIONS, 91 - Gif-sur-Yvette (France); Zemb, T. [ICSM, UMR 5257 CEA/CNRS/UM2/ENSCM, 30 - Bagnols sur Ceze (France)

    2009-03-15

    The properties of new thermo-responsive functional surfactants, capable of forming a metal chelate, synthesized by grafting a diamide group (amino-acid residue) to the tip hydrophilic endgroup or in a branched position to polyoxyethylene nonionic surfactants [C{sub i}E{sub j}:C{sub i}H{sub 2i+1}(OCH{sub 2}CH{sub 2}){sub j}OH)], are studied. Their use in cloud point extraction of uranyl nitrate is tested. The reversible temperature-dependent behavior of classical non-ionic surfactants associated to phase separation of micellar solutions known as clouding behavior is exploited for separation based on cation specific binding to the chelating group. The functional surfactants under investigation combine surface-active properties and characteristic thermoreversible behavior with a capacity to bind uranyl cation. The influence of the complexation on the cloud points of functional surfactants is determined. The chelating surfactants are found efficient for the cloud point extraction of uranyl nitrate at low surfactant-to-uranyl ratio. These new thermoresponsive surfactants with chelating properties hold most promise for the development of new solvent free extraction processes.

  15. Thermo-responsive Metal-chelating Surfactants: Properties and Use in Cloud Point Extraction of Uranyl Nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Prevost, S.; Coulombeau, H.; Baczko, K.; Larpent, C. [Univ Versailles St Wuentin Y, Inst Lavoisier, UMR 8180, CNRS, F-78035 Versailles, (France); Prevost, S.; Coulombeau, H.; Desvaux, H.; Testard, F. [CEA, IRAMIS, SCM, LIONS, F-91191 Gif Sur Yvette, (France); Berthon, L.; Zorz, N. [CEA, DEN DRCP SCPS LCSE, F-30207 Bagnols Sur Ceze, (France); Zemb, Th. [ICSM, UMR 5257, CEA CNRS UM2 ENSCM, F-30207 Bagnols Sur Ceze, (France)

    2009-07-01

    The properties of new thermo-responsive functional surfactants, capable of forming a metal chelate, synthesized by grafting a diamide group (amino-acid residue) to the tip hydrophilic end-group or in a branched position to polyoxyethylene nonionic surfactants [CiEj: C{sub i}H{sub 2i+1}(OCH{sub 2}CH{sub 2}){sub j}OH)], are studied. Their use in cloud point extraction of uranyl nitrate is tested. The reversible temperature-dependent behavior of classical non-ionic surfactants associated to phase separation of micellar solutions known as clouding behavior is exploited for separation based on cation specific binding to the chelating group. The functional surfactants under investigation combine surface-active properties and characteristic thermo-reversible behavior with a capacity to bind uranyl cation. The influence of the complexation on the cloud points of functional surfactants is determined. The chelating surfactants are found efficient for the cloud point extraction of uranyl nitrate at low surfactant-to-uranyl ratio. These new thermo-responsive surfactants with chelating properties hold most promise for the development of new solvent free extraction processes. (authors)

  16. Extracting Metallic Nanoparticles from Soils for Quantitative Analysis: Method Development Using Engineered Silver Nanoparticles and SP-ICP-MS.

    Science.gov (United States)

    Schwertfeger, D M; Velicogna, Jessica R; Jesmer, Alexander H; Saatcioglu, Selin; McShane, Heather; Scroggins, Richard P; Princz, Juliska I

    2017-02-21

    The lack of an efficient and standardized method to disperse soil particles and quantitatively subsample the nanoparticulate fraction for characterization analyses is hindering progress in assessing the fate and toxicity of metallic engineered nanomaterials in the soil environment. This study investigates various soil extraction and extract preparation techniques for their ability to remove nanoparticulate Ag from a field soil amended with biosolids contaminated with engineered silver nanoparticles (AgNPs), while presenting a suitable suspension for quantitative single-particle inductively coupled plasma mass spectroscopy (SP-ICP-MS) analysis. Extraction parameters investigated included reagent type (water, NaNO3, KNO3, tetrasodium pyrophosphate (TSPP), tetramethylammonium hydroxide (TMAH)), soil-to-reagent ratio, homogenization techniques as well as procedures commonly used to separate nanoparticles from larger colloids prior to analysis (filtration, centrifugation, and sedimentation). We assessed the efficacy of the extraction procedure by testing for the occurrence of potential procedural artifacts (dissolution, agglomeration) using a dissolved/particulate Ag mass ratio and by monitoring the amount of Ag mass in discrete particles. The optimal method employed 2.5 mM TSPP used in a 1:100 (m/v) soil-to-reagent ratio, with ultrasonication to enhance particle dispersion and sedimentation to settle out the micrometer-sized particles. A spiked-sample recovery analysis shows that 96% ± 2% of the total Ag mass added as engineered AgNP is recovered, which includes the recovery of 84.1% of the particles added, while particle recovery in a spiked method blank is ∼100%, indicating that both the extraction and settling procedure have a minimal effect on driving transformation processes. A soil dilution experiment showed that the method extracted a consistent proportion of nanoparticulate Ag (9.2% ± 1.4% of the total Ag) in samples containing 100%, 50%, 25%, and 10

  17. Evaluating the mobile heavy metal pool in soak-away sediment, road dust and soil through sequential extraction and isotopic exchange.

    Science.gov (United States)

    Kumar, Manish; Furumai, Hiroaki; Kurisu, Futoshi; Kasuga, Ikuro

    2010-01-01

    Selective sequential dissolution (SSD) and isotopic dilution are two most commonly applied techniques for the measurement of mobile fraction of heavy metal present in the urban environment. This work examined the compliance between SSD proposed by the Community Bureau of Reference (BCR) and isotopic dilution technique (IDT) for determination of mobile pool of heavy metal contained in soakaway sediment, road dust, and soil sample. Heavy metals (Cu, Zn, Cd and Pb) were fractionated using the three-stage BCR protocol, while isotopically exchangeable metal concentrations (E-value) were investigated through isotopic tracers (¹¹¹Cd, ⁶⁵Cu, ²⁰⁷Pb and ⁶⁶Zn). In general, total contamination level, E-value and BCR exchangeable fractions of different samples followed the similar order of road dust > soakaway sediment > soil. Results revealed that the E-value exceeded the BCR exchangeable fraction in all samples. In addition, the first three fractions of BCR which have potential to become mobile under certain environmental conditions were collectively termed as "potential mobile pool" and compared with E-value. It was concluded that metal extracted by weak acid underestimates the exchangeable fraction while the potential mobile pool extracted by three reagents overestimates the real mobile forms of heavy metals. However, better mobility characteristics of heavy metals can be assessed by coupling information obtained through sequential extraction and isotopic exchange.

  18. Preparation, structural, and calorimetric characterization of bicomponent metallic photonic crystals

    Science.gov (United States)

    Kozlov, M. E.; Murthy, N. S.; Udod, I.; Khayrullin, I. I.; Baughman, R. H.; Zakhidov, A. A.

    2007-03-01

    We report preparation and characterization of novel bicomponent metal-based photonic crystals having submicron three-dimensional (3D) periodicity. Fabricated photonic crystals include SiO2 sphere lattices infiltrated interstitially with metals, carbon inverse lattices filled with metal or metal alloy spheres, Sb inverse lattices, and Sb inverse lattices filled with Bi spheres. Starting from a face centered SiO2 lattice template, these materials were obtained by sequences of either templating and template extraction or templating, template extraction, and retemplating. Surprising high fidelity was obtained for all templating and template extraction steps. Scanning electron microscopy (SEM), small angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) were used to characterize the structure and the effects of the structure on calorimetric properties. To the best of our knowledge, SAXS data on metallic photonic crystals were collected for first time.

  19. Preparation, structural, and calorimetric characterization of bicomponent metallic photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kozlov, M.E.; Baughman, R.H.; Zakhidov, A.A. [The University of Texas at Dallas, NanoTech Institute, Richardson, TX (United States); Murthy, N.S. [University of Vermont, Department of Physics, Burlington, VT (United States); Udod, I. [Teva Pharmaceuticals USA, Fairfield, NJ (United States); Khayrullin, I.I. [eMagin Corporation, Hopewell Junction, NY (United States)

    2007-03-15

    We report preparation and characterization of novel bicomponent metal-based photonic crystals having submicron three-dimensional (3D) periodicity. Fabricated photonic crystals include SiO{sub 2} sphere lattices infiltrated interstitially with metals, carbon inverse lattices filled with metal or metal alloy spheres, Sb inverse lattices, and Sb inverse lattices filled with Bi spheres. Starting from a face centered SiO{sub 2} lattice template, these materials were obtained by sequences of either templating and template extraction or templating, template extraction, and retemplating. Surprising high fidelity was obtained for all templating and template extraction steps. Scanning electron microscopy (SEM), small angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) were used to characterize the structure and the effects of the structure on calorimetric properties. To the best of our knowledge, SAXS data on metallic photonic crystals were collected for first time. (orig.)

  20. Metal fractionation of atmospheric aerosols via sequential chemical extraction: a review

    Energy Technology Data Exchange (ETDEWEB)

    Smichowski, Patricia; Gomez, Dario [Unidad de Actividad Quimica, Comision Nacional de Energia Atomica, San Martin (Argentina); Polla, Griselda [Unidad de Actividad Fisica, Comision Nacional de Energia Atomica, San Martin (Argentina)

    2005-01-01

    This review surveys schemes used to sequentially chemically fractionate metals and metalloids present in airborne particulate matter. It focuses mainly on sequential chemical fractionation schemes published over the last 15 years. These schemes have been classified into five main categories: (1) based on Tessier's procedure, (2) based on Chester's procedure, (3) based on Zatka's procedure, (4) based on BCR procedure, and (5) other procedures. The operational characteristics as well as the state of the art in metal fractionation of airborne particulate matter, fly ashes and workroom aerosols, in terms of applications, optimizations and innovations, are also described. Many references to other works in this area are provided. (orig.)

  1. Tannin-Metal Interactions in Soils: An Incubation-Extraction Approach in Hill-Land Environments

    Science.gov (United States)

    Gonzalez, J. M.; Halvorson, J. J.

    2007-12-01

    Tannins, plant polyphenols known to react with proteins, metals and soil organic matter, are commonly found in the vegetation growing in Appalachian hill-lands. Establishing silvopastoral grazing systems in these environments is a means for improving productivity however the fate of tannins in soils and, in particular, the effect on solubility/mobility of metals in soils is poorly understood. Soils from forest and pasture systems were sampled from two depths, treated with tannic acid or related phenolic compounds, and analyzed for metals in solution. The amount of Mn and Ca detected in solution varied among the different phenolic treatments, highest for gallic acid, and was also influenced by depth and land use. As expected, the Ca content in solution was correlated with the electrical conductivity (EC) and the Mn content was correlated with the redox potential in solution. Interestingly, the EC was also correlated with both Mn content and redox potential. The higher Ca content found in solution may result from the low pH of the phenolic compounds. The higher Mn in solution may result from the redox reaction of Mn (IV) oxides with the phenolic compounds, producing soluble Mn2+ and quinones. These quinones are very reactive compounds that can self-polymerize and/or copolymerize with other biomolecules, such as amino-containing compounds and carbohydrates, to form humic-like substances. Successful management of silvopastures, requires an understanding of factors that affect the quality and quantity of plant secondary compounds like tannins entering soil not only to increase forage productivity but also to enhance formation/stabilization of soil organic matter to increase nutrient cycling and reduce the toxicity risk of some metals such as Mn.

  2. Recycling of red muds with the extraction of metals and special additions to cement

    Science.gov (United States)

    Zinoveev, D. V.; Diubanov, V. G.; Shutova, A. V.; Ziniaeva, M. V.

    2015-01-01

    The liquid-phase reduction of iron oxides from red mud is experimentally studied. It is shown that, in addition to a metal, a slag suitable for utilization in the construction industry can be produced as a result of pyrometallurgical processing of red mud. Portland cement is shown to be produced from this slag with mineral additions and a high-aluminate expansion addition to cement.

  3. Dynamics and thermodynamics of toxic metals adsorption onto soil-extracted humic acid.

    Science.gov (United States)

    Shaker, Medhat A; albishri, Hassan M

    2014-09-01

    Humic acids, HA represent a large portion of natural organic matter in soils, sediments and waters. They are environmentally important materials due to their extensive ubiquity and strong complexation ability, which can influence heavy metal removal and transportation in waters. The thermodynamics and kinetics of the adsorption of Cd(II) and Cr(VI) onto solid soil-derived HA have been investigated at optimum conditions of pH (5.5±0.1), metal concentration (10-100mmolL(-1)) and different temperatures (293-323K). The suitability of adsorption models such as Freundlich and Langmuir to equilibrium data was investigated. The adsorption was well described by Langmuir isotherm model in multi-detectable steps. Adsorption sites, i (i=A, B, C) with different capacities, νi are characterized. The stoichiometric site capacity is independent of temperature and equilibrium constant, Ki. Adsorption sites A and B are selectively occupied by Cr(VI) cations while sites A and C are selectively occupied by Cd(II) cations. The thermodynamic parameters of adsorption systems are correlated for each adsorption step. The adsorption is endothermic, spontaneous and favorable. Different kinetic models are applied and the adsorption of these heavy metals onto HA follows pseudo-second-order kinetics and equilibrium is achieved within 24h. The adsorption reaction is controlled by diffusion processes and the type of the adsorption is physical.

  4. Heavy metals extractability in a soil amended with sewage sludge Extractabilidade de metais pesados em um solo tratado com lodo de esgoto

    Directory of Open Access Journals (Sweden)

    Giuliano Marchi

    2009-10-01

    Full Text Available Few investigations have been carried out about the comparison of desorption rate and amount of heavy metals extracted successively by organic acid mixtures mimicking the rhizosphere and routine extractants in sewage sludge-amended soils. Extractions of Zn, Cd, Ni, Cr, and Cu were performed in samples of a sewage sludge-amended soil using seven extractants: four organic acid mixtures and three routine extractants (DTPA, Mehlich-I, and ammonium acetate. Results from single pass extractions, in which the extractable metal contents were determined by simply extracting the soil a single time, as well as from 15 successive extractions, in which the solid residues of the first extraction was successively extracted 14 additional times, of heavy metals were analyzed. The extractability of heavy metals in a single pass extraction was, in general, as follows: Mehlich-I > DTPA > organic acids > NH4OAc. The highest rates of extraction followed the general order: DTPA > Mehlich-I > organic acids > NH4OAc. While Mehlich-I presented the highest extractability of heavy metals among studied extractants, DTPA showed a high extractability of Zn, Cd, Ni, and Cu in a single extraction as well as the highest rates of extraction among the studied extractants. The transfer of heavy metals from soil to organic acid solutions is slower than to DTPA and Mehlich-I extractants.Poucos trabalhos têm sido realizados sobre a comparação da taxa de dessorção e da quantidade de metais extraídos sucessivamente por misturas de ácidos orgânicos que imitam a composição da rizosfera e por extratores usados na rotina em amostras de solo tratado com lodo de esgoto. Extrações de Zn, Cd, Ni, Cr e Cu foram realizadas em amostras de um solo de carga variável tratado com lodo de esgoto usando-se sete extratores: quatro misturas com ácidos orgânicos e três extratores usados na rotina (DTPA, Mehlich-I e acetato de amônio. Os resultados para uma única extração, em que o conte

  5. Fractionation of heavy metals in liquefied chromated copper arsenate 9-treated wood sludge using a modified BCR-sequential extraction procedure.

    Science.gov (United States)

    Pan, Hui; Hse, Chung-Yun; Gambrell, Robert; Shupe, Todd F

    2009-09-01

    Chromated copper arsenate (CCA)-treated wood was liquefied with polyethylene glycol/glycerin and sulfuric acid. After liquefaction, most CCA metals (98% As, 92% Cr, and 83% Cu) were removed from liquefied CCA-treated wood by precipitation with calcium hydroxide. The original CCA-treated wood and liquefied CCA-treated wood sludge were fractionated by a modified Community Bureau of Reference (BCR) sequential extraction procedure. The purpose of the BCR-sequential extraction used in this study was to examine the availability of CCA metals in treated wood for reuse. Both As and Cr had a slightly higher concentration in the sludge sample than in original CCA-treated wood. The sequential extraction showed that As and Cr were principally existed in an oxidizable fraction (As, 67%; Cr, 88%) in original CCA-treated wood. Only 1% of both As and Cr were extracted by hot nitric acid with the last extraction step. The distribution of As and Cr changed markedly in liquefied CCA-treated wood sludge. The amount of As in the exchangeable/acid extractable fraction increased from 16% to 85% while the amount of Cr increased from 3% to 54%. Only about 3% of As was present in the oxidizable fraction. However, there was still about 34% of Cr in the same fraction. Based on these results from sequential extraction procedures, it can be concluded that the accessibilities of CCA metals increase markedly by the liquefaction-precipitation process.

  6. Di-ionizable p-tert-butylcalix[4]arene-1,2-crown-3 ligands in cone and 1,2-alternate conformations: synthesis and metal ion extraction.

    Science.gov (United States)

    Zhang, Dongmei; Cao, Xiaodan; Purkiss, David W; Bartsch, Richard A

    2007-04-21

    Novel di-ionizable p-tert-butylcalix[4]arene-1,2-crown-3 ligands in cone and 1,2-alternate conformations were prepared as potential metal ion extractants. Selective bridging of proximal hydroxyl groups of the calix[4]arene platform by a crown-3 polyether unit was achieved under Mitsunobu reaction conditions. In addition to the carboxylic acid group, the acidity tunable N-(X)sulfonyl oxyacetamide functions [OCH(2)C(O)NHSO(2)X] with X group variation from methyl to phenyl to p-nitrophenyl to trifluomethyl were used as the proton-ionizable groups. Conformations and regioselectivities of the new ligands were established by (1)H and (13)C NMR spectroscopy. Competitive solvent extractions of alkali metal cations and of alkaline earth metal cations from aqueous solutions into chloroform were performed, as were single species extractions of lead(ii) and mercury(ii).

  7. Processing of copper anodic-slimes for extraction of valuable metals.

    Science.gov (United States)

    Amer, A M

    2003-01-01

    This work focuses on processing of anodic slimes obtained from an Egyptian copper electrorefining plant. The anodic slimes are characterized by high concentrations of copper, lead, tin and silver. The proposed hydrometallurgical process consists of two leaching stages for the extraction of copper (H(2)SO(4)-O(2)) and silver (thiourea-Fe3+), and pyrometallurgical treatment of the remaining slimes for production of Pb-Sn soldering alloy. Factors affecting both the leaching and smelting stages were studied.

  8. Chemical and biological processes for multi-metal extraction from waste printed circuit boards of computers and mobile phones.

    Science.gov (United States)

    Shah, Monal B; Tipre, Devayani R; Dave, Shailesh R

    2014-11-01

    E-waste printed circuit boards (PCB) of computers, mobile-phones, televisions, LX (LongXiang) PCB in LED lights and bulbs, and tube-lights were crushed to ≥250 µm particle size and 16 different metals were analysed. A comparative study has been carried out to evaluate the extraction of Cu-Zn-Ni from computer printed circuit boards (c-PCB) and mobile-phone printed circuit boards (m-PCB) by chemical and biological methods. Chemical process showed the extraction of Cu-Zn-Ni by ferric sulphate was best among the studied chemical lixiviants. Bioleaching experiments were carried out with the iron oxidising consortium, which showed that when E-waste and inoculum were added simultaneously in the medium (one-step process); 60.33% and 87.50% Cu, 75.67% and 85.67% Zn and 71.09% and 81.87% Ni were extracted from 10 g L(-1) of c-PCB and m-PCB, respectively, within 10-15 days of reaction time. Whereas, E-waste added after the complete oxidation of Fe(2+) to Fe(3+) iron containing medium (two-step process) showed 85.26% and 99.99% Cu, 96.75% and 99.49% Zn and 93.23% and 84.21% Ni extraction from c-PCB and m-PCB, respectively, only in 6-8 days. Influence of varying biogenerated Fe(3+) and c-PCB concentrations showed that 16.5 g L(-1) of Fe(3+) iron was optimum up to 100 g L(-1) of c-PCB. Changes in pH, acid consumed and redox potential during the process were also studied. The present study shows the ability of an eco-friendly process for the recovery of multi-metals from E-waste even at 100 g L(-1) printed circuit boards concentration. © The Author(s) 2014.

  9. Reproducibility of the BCR sequential extraction procedure in a long-term study of the association of heavy metals with soil components in an upland catchment in Scotland.

    Science.gov (United States)

    Bacon, Jeffrey R; Hewitt, Irene J; Cooper, Patricia

    2005-01-20

    Humic iron podzol soils from three different plots at the Glensaugh Research Station, Aberdeenshire have been sampled on an annual basis since 1990 and analysed using both total digestion and the original BCR sequential extraction procedure. Particular care was required during the oxidation of these organic soils to prevent loss of material. The residue from the sequential extraction was analysed so that the values for total concentration derived from the total digestion and from the sum of the concentrations in the fractions of the extraction procedure could be compared. The comparison was good for all three soils indicating that not only did the sequential extraction give good recovery but that this was reproducible over a period of several years. The proportion of metals extractable at each step remained relatively constant thereby demonstrating the reproducibility of the procedure and the stability of the metals in the soils over the time scale of the sampling used. Whereas the total concentrations of Cr, Cu and Ni were highest in the soil from a roadside plot, this was not the case for Cd, Pb and Zn. In the case of Pb, concentrations in soils (0-25-cm depth) well away from the road were over 100 mg/kg and well above the expected background level. The distribution of metals between each of the extracted fractions varied not only between each metal but also between each of the three soils indicating that both metal and soil influenced the measured distribution. The distribution of Pb in the roadside soil was different from those in the other two soils and over 10% was extracted in the first, acetic acid soluble, fraction.

  10. Transport of yttrium metal ions through fibers supported liquid membrane solvent extraction

    Institute of Scientific and Technical Information of China (English)

    A.G.Gaikwad; A.M.Rajput

    2010-01-01

    A novel idea of transport of yttrium(Ⅲ) metal ions through fibers supported liquid membrane in two stage processes namely source to membrane and membrane to receiving phase has been proposed.The fibers supported liquid membrane was impregnated with different concentrations carrier.The experimental variables explored were concentration of yttrium(Ⅲ) ions,pH of source phase,PC-88A concentration in membrane phase,acid concentration in receiving phase and stirring speed.The pre-concentration of yttrium(Ⅲ) ions ...

  11. Microwave and camera sensor fusion for the shape extraction of metallic 3D space objects

    Science.gov (United States)

    Shaw, Scott W.; Defigueiredo, Rui J. P.; Krishen, Kumar

    1989-01-01

    The vacuum of space presents special problems for optical image sensors. Metallic objects in this environment can produce intense specular reflections and deep shadows. By combining the polarized RCS with an incomplete camera image, it has become possible to better determine the shape of some simple three-dimensional objects. The radar data are used in an iterative procedure that generates successive approximations to the target shape by minimizing the error between computed scattering cross-sections and the observed radar returns. Favorable results have been obtained for simulations and experiments reconstructing plates, ellipsoids, and arbitrary surfaces.

  12. Efficiency of single extraction schemes in highlighting the impact of changes in land use of contaminated agricultural soils on their trace metal availability

    Science.gov (United States)

    Iqbal, Muhammad; Lamy, Isabelle; Bermond, Alain

    2014-05-01

    Presently changes in the land use of contaminated and marginal agricultural lands from conventional annual food crops to perennial non-food bionergy crops are being encouraged globally. This is being done to avoid food chain contamination with metal and organic contaminants and to meet world energy needs without disturbing normal fertile agricultural lands. Changes in land use from the annual cropping systems to the perennial cropping systems are known to modify organic matter quality and quantity in case of non contaminated soils. In the case of contaminated soils such changes are susceptible to alter trace metal availabilities but studies reporting such changes are scarce. Different single extraction protocols are used to assess the trace element availability in soils. The efficiency of these extractants depends upon soil conditions and may vary case to case. The objective of the present work was to assess the changes in trace metal availability of contaminated soils when annual crops system is replaced by a perennial crop system using different single extraction protocols. A strategy of studying Cd and Zn availabilities of two sites differing in the soil texture and origin of pollution was adopted i.e. the site of Metaleurop (North of France) and the site of Pierrelaye (Paris Region). They differed in the degree of metal pollution (for Cu, Pb, Cd and Zn) and in the quantity and nature of organic matter (different C/N values). The samples used for this study involved the soils under annual crops and the perennial crop i.e. miscanthus. We investigated the trace metal availabilities of the soils using different single extraction protocols involving chemical metal extractions with EDTA, DTPA and NH4NO3 at equilibrium and kinetic EDTA extractions. The results for the soil under miscanthus compared to annual crop soil showed that single extraction schemes using chelating agents like EDTA and DTPA, however, failed to show if the metal availability can be impacted by

  13. Avaliação radiográfica do comportamento dos terceiros molares inferiores em pacientes tratados ortodonticamente com e sem extrações de primeiros pré-molares Radiographic evaluation of the behavior of lower third molars in patients that were orthodontically treated with and without first premolars extractions

    Directory of Open Access Journals (Sweden)

    Reinaldo Roberto Hauy

    2007-12-01

    Full Text Available OBJETIVO: o presente trabalho objetivou avaliar as alterações ocorridas nas posições dos terceiros molares inferiores em pacientes tratados ortodonticamente com extrações dos primeiros pré-molares. METODOLOGIA: utilizou-se 80 ortopantomografias, obtidas no pré e pós-tratamento ortodôntico corretivo de 40 pacientes, divididos em dois grupos. O grupo 1 constou de 20 pacientes (13 femininos e 7 masculinos que se submeteram a tratamento ortodôntico com extrações de primeiros pré-molares. O grupo 2 foi constituído por 20 pacientes (13 femininos e 7 masculinos tratados ortodonticamente sem extrações. Foram estabelecidas medidas angulares, com o objetivo de avaliar as inclinações e medidas lineares, para analisar as modificações no sentido vertical dos terceiros molares. Todos os dados foram mensurados duas vezes, cujos valores médios foram submetidos dos testes t emparelhado e teste t independente. RESULTADOS: os resultados mostraram diferenças estatisticamente significantes (pAIM: The aim of this study is to evaluate the positional changes occurred with lower third molars in patients treated orthodontically with extractions of first premolars. METHODS: A total of 80 panoramic radiographs obtained at pre and post-treatment periods from 40 patients, were divided into 2 groups: group 1 were composed by 20 patients (13 female and 7 male that were submitted to orthodontic treatment with extraction of first premolars; group 2 were composed by 20 patients (13 female and 7 male that were submitted to orthodontic treatment without extractions. Angular measurements were established to evaluate the tipping and linear measurements were established to analyze the vertical changes of the lower third molars. All data were measured twice and averaged, then submitted to paired and unpaired test. RESULTS: Significant differences were found between the initial and final angular measurements of group 1 (p<0.01. CONCLUSIONS: It was concluded that

  14. Processing of copper converter slag for metal reclamation. Part I: Extraction and recovery of copper and cobalt.

    Science.gov (United States)

    Deng, Tong; Ling, Yunhan

    2007-10-01

    Clean processing of copper converter slag to reclaim cobalt and copper could be a challenge. An innovative and environmentally sound approach for recovering valuable metals from such a slag has been developed in the present study. Curing the slag with strong sulphuric acid, without re-smelting or roasting as practiced currently in the industry, render it accessible to leaching, and more than 95% of cobalt and up to 90% of copper was extracted together with iron by water leaching, leaving silica behind in a residue. The copper in the leach liquor was recovered by cementation with iron and the dissolved iron crystallized as ferrous sulphate monohydrate. The cobalt in the mother-liquor rich in iron was recovered by either cementation or sulphide precipitation. Operation variables in the new process were also investigated and optimized.

  15. Graphene-Based Materials as Solid Phase Extraction Sorbent for Trace Metal Ions, Organic Compounds, and Biological Sample Preparation.

    Science.gov (United States)

    Ibrahim, Wan Aini Wan; Nodeh, Hamid Rashidi; Sanagi, Mohd Marsin

    2016-07-03

    Graphene is a new carbon-based material that is of interest in separation science. Graphene has extraordinary properties including nano size, high surface area, thermal and chemical stability, and excellent adsorption affinity to pollutants. Its adsorption mechanisms are through non-covalent interactions (π-π stacking, electrostatic interactions, and H-bonding) for organic compounds and covalent interactions for metal ions. These properties have led to graphene-based material becoming a desirable adsorbent in a popular sample preparation technique known as solid phase extraction (SPE). Numerous studies have been published on graphene applications in recent years, but few review papers have focused on its applications in analytical chemistry. This article focuses on recent preconcentration of trace elements, organic compounds, and biological species using SPE-based graphene, graphene oxide, and their modified forms. Solid phase microextraction and micro SPE (µSPE) methods based on graphene are discussed.

  16. Comparison of the extraction efficiencies of different leaching agents for reliable assessment of bio-accessible trace metal fractions in airborne particulate matter

    Directory of Open Access Journals (Sweden)

    Mukhtar A.

    2013-04-01

    Full Text Available In present study, an in-vitro physiologically based extraction test has been applied for extraction of bio-accessible trace metal fractions in airborne particulate matter (APM samples collected from different urban sites in Austria and Pakistan using the leaching agents H2O, sodium chloride, ammonium acetate, ammonium citrate, synthetic gastric juice and artificial lung fluids. Obtained extracts were then measured using an ETV-ICP-OES procedure which allowed highly sensitive measurement of dissolved analytes even in the presence of leaching agents. Derived results indicated that the investigated leaching agents extract different amounts of trace metals. In general, leaching agents with organic nature yielded comparatively greater extractable and thus bio-accessible trace metal fractions to that of simple solvents like H2O or aqueous NaCl solution. With water, only 26.3±4.0% of Cd was found to be bio-accessible whereas 88.4±24.8 of Cd was obtained as bio-accessible fraction with the use of synthetic gastric juice. The concentrations of bio-accessible metal fractions varied from 0.4 ng m−3 (Cd to 714 ng m−3 (Zn and 0.3 ng m−3 (Cd to 190 ng m−3 (Zn for PM10 samples collected from Karachi (Pakistan and Graz (Austria respectively.

  17. Ultrasound-assisted magnetic solid-phase extraction for the determination of some transition metals in Orujo spirit samples by capillary electrophoresis.

    Science.gov (United States)

    Peña Crecente, Rosa M; Lovera, Carlha Gutiérrez; García, Julia Barciela; Latorre, Carlos Herrero; Martín, Sagrario García

    2016-01-01

    Ultrasound-assisted magnetic solid-phase extraction coupled to capillary electrophoresis was optimized for the preconcentration and determination of Zn(II), Cu(II), Mn(II) and Cd(II) as their complexes with 1,10-phenanthroline (Phen). Both pre- and on-capillary complexations were employed to obtain stable metal-Phen complexes. The parameters that have an influence on the electrophoretic separation and the MSPE process were studied and optimized using different experimental designs. Metals were extracted from 10 mL of sample at pH 5 using 3mg of magnetic particles functionalized with carboxylic groups. The metals were eluted as metal-Phen complexes and analyzed by capillary electrophoresis. The method showed low limits of detection for metals 0.49-2.19 μg L(-1), and high preconcentration factors, 39-44, The efficiencies of the extraction method were in the range 77.1-87.5% and the precision (RSD < 10%) and accuracy were between 98.2% and 101.6%. The method was applied to the determination of the aforementioned metals in Galician Orujo spirit samples.

  18. Solvent Extraction of Alkaline Earth Metals with Alkylphosphorus Acids%有机磷(膦)酸对碱土金属的萃取

    Institute of Scientific and Technical Information of China (English)

    许新; 朱屯

    2002-01-01

    Solvent extraction equilibria of four main alkaline earth metals (magnesium, calcium, strontium and barium) with di(2-ethylhexyl) phosphoric acid (DEHPA), 2-ethylhexyl phosphonic acid mono-(2-ethylhexyl) ester,di(2,4,4-tri-methylpentyl) phosphinic acid and IR spectra of the extracts have been studied. The selectivity order is dependent on the e/r value and hydration energy of the metal ions. The minor shift of the P-O in IR absorption of the alkaline earth metal extracts indicates that the interaction between the metal ions and P-O is much weaker for alkaline earth metals than for transitional metals. The distribution of the four alkaline earth elements between aqueous solutions and solutions of DEHPA and neutral organophosphorus compounds, tri-n-butyl phosphate (TBP) or tri-octyl phosphine oxide (TOPO) in kerosene have been determined at varying ratio of TBP or TOPO to DEHPA and the positive synergism is observed. The synergic effect is explained by using IR spectra of the loaded organic phase.

  19. Reduction of Metal Oxide to Metal using Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Ramana Reddy

    2012-04-12

    A novel pathway for the high efficiency production of metal from metal oxide means of electrolysis in ionic liquids at low temperature was investigated. The main emphasis was to eliminate the use of carbon and high temperature application in the reduction of metal oxides to metals. The emphasis of this research was to produce metals such as Zn, and Pb that are normally produced by the application of very high temperatures. The reduction of zinc oxide to zinc and lead oxide to lead were investigated. This study involved three steps in accomplishing the final goal of reduction of metal oxide to metal using ionic liquids: 1) Dissolution of metal oxide in an ionic liquid, 2) Determination of reduction potential using cyclic voltammetry (CV) and 3) Reduction of the dissolved metal oxide. Ionic liquids provide additional advantage by offering a wide potential range for the deposition. In each and every step of the process, more than one process variable has been examined. Experimental results for electrochemical extraction of Zn from ZnO and Pb from PbO using eutectic mixtures of Urea ((NH2)2CO) and Choline chloride (HOC2H4N(CH3)3+Cl-) or (ChCl) in a molar ratio 2:1, varying voltage and temperatures were carried out. Fourier Transform Infra-Red (FTIR) spectroscopy studies of ionic liquids with and without metal oxide additions were conducted. FTIR and induction coupled plasma spectroscopy (ICPS) was used in the characterization of the metal oxide dissolved ionic liquid. Electrochemical experiments were conducted using EG&G potentiostat/galvanostat with three electrode cell systems. Cyclic voltammetry was used in the determination of reduction potentials for the deposition of metals. Chronoamperometric experiments were carried out in the potential range of -0.6V to -1.9V for lead and -1.4V to -1.9V for zinc. The deposits were characterized using XRD and SEM-EDS for phase, morphological and elemental analysis. The results showed that pure metal was deposited on the cathode

  20. Extraction of heavy metals characteristics of the 2011 Tohoku tsunami deposits using multiple classification analysis.

    Science.gov (United States)

    Nakamura, Kengo; Kuwatani, Tatsu; Kawabe, Yoshishige; Komai, Takeshi

    2016-02-01

    Tsunami deposits accumulated on the Tohoku coastal area in Japan due to the impact of the Tohoku-oki earthquake. In the study reported in this paper, we applied principal component analysis (PCA) and cluster analysis (CA) to determine the concentrations of heavy metals in tsunami deposits that had been diluted with water or digested using 1 M HCl. The results suggest that the environmental risk is relatively low, evidenced by the following geometric mean concentrations: Pb, 16 mg kg(-1) and 0.003 ml L(-1); As, 1.8 mg kg(-1) and 0.004 ml L(-1); and Cd, 0.17 mg kg(-1) and 0.0001 ml L(-1). CA was performed after outliers were excluded using PCA. The analysis grouped the concentrations of heavy metals for leaching in water and acid. For the acid case, the first cluster contained Ni, Fe, Cd, Cu, Al, Cr, Zn, and Mn; while the second contained Pb, Sb, As, and Mo. For water, the first cluster contained Ni, Fe, Al, and Cr; and the second cluster contained Mo, Sb, As, Cu, Zn, Pb, and Mn. Statistical analysis revealed that the typical toxic elements, As, Pb, and Cd have steady correlations for acid leaching but are relatively sparse for water leaching. Pb and As from the tsunami deposits seemed to reveal a kind of redox elution mechanism using 1 M HCl.

  1. Sequential extraction as a tool for mobility studies of radionuclides and metals in soils and sediments

    Energy Technology Data Exchange (ETDEWEB)

    Skipperud, Lindis; Salbu, Brit [Norwegian Univ. of Life Sciences, Aas (Norway). Dept. of Environmental Sciences (IMV)

    2015-06-01

    To assess the long term environmental impact of radioactive contamination of ecosystems, information on source terms including radionuclide speciation, mobility and biological uptake is of high importance. The speciation of radionuclides deposited or occurring naturally depends on source term and release scenario characteristics, transport and dispersion mechanisms and ecosystem properties. If mobile species are present, ecosystem transfer is relatively fast, whereas the ecosystem transfer is delayed if radionuclides are present as particles or incorporated in mineral lattices. This paper discusses cases showing important factors influencing the mobility of different radionuclides and metals. As examples can be given: - the difference between {sup 137}Cs and {sup 90}Sr from Chernobyl fallout and stable Cs and Sr in the soil showing that the fallout has not reached a steady state and therefore shows different mobility properties, thus the time since contamination is important. - the presence of organic matter affect the mobility of plutonium in soils and sediments even though the source term is the same. - physical properties (i.e. pH, OM, clay content, grain sice etc.) is important to interpret mobility data between similar sites. - the influence of industrial activity on radionuclides and metals shows that any man-made activity might change the mobility.

  2. Replica of human dentin treated with different desensitizing agents: a methodological SEM study in vitro

    Directory of Open Access Journals (Sweden)

    Pereira Jose Carlos

    2002-01-01

    Full Text Available This is a preliminary study to determine a methodological sequence in vitro which may allow the reproduction of dentin for SEM analysis, after the use of different desensitizing agents. Dentin discs obtained from extracted human third molars were etched with 6% citric acid, an artificial smear layer was created and the surface dentin discs were divided into four quadrants. Quadrants 2, 3 and 4 of each disc were conditioned with 6% citric acid. The desensitizing agents (Oxa-Gel®, Gluma Desensitizer and an experimental agent were applied to quadrants 3 and 4. To evaluate the acid resistance of the treatment, quadrant 4 was etched again with 6% citric acid. An impression was then taken with Aquasil ULV. After a setting period of 6 min, each disc was removed from the impression and stored in a moist-free environment for 24 h at 37ºC. After that time, a low-viscosity epoxy resin (Araltec GY 1109 BR was poured into the impression and cured for 24 h. All specimens were metal-coated for SEM analysis. Comparison of the photomicrographs of dentin discs with their respective impressions and resin replicas showed that this technique can reproduce the characteristics of the dentin surface treated with desensitizing agents.

  3. Solid-liquid extraction of alkali metals and organic compounds by leaching of food industry residues.

    Science.gov (United States)

    Yu, Chaowei; Zheng, Yi; Cheng, Yu-Shen; Jenkins, Bryan M; Zhang, Ruihong; VanderGheynst, Jean S

    2010-06-01

    Leaching was studied for its application in extracting inorganic and organic constituents from fresh fermented grape pomace, air-dried fermented grape pomace and air-dried sugar beet pulp. Samples of each feedstock were leached in water at ambient temperature for 30 or 120 min at dry solid-to-liquid ratios of 1/20 and 1/50 kg/L. Leaching removed 82% of sodium, 86% of potassium, and 76% of chlorine from sugar beet pulp, and reduced total ash concentration in air-dry fermented grape pomace from 8.2% to 2.9% of dry matter, 8.2% to 4.4% in fresh fermented grape pomace, and 12.5% to 5.4% in sugar beet pulp. Glycerol (7-11 mg/dry g), ethanol (131-158 mg/dry g), and acetic acid (24-31 mg/dry g) were also extracted from fermented grape pomace. These results indicate that leaching is a beneficial pretreatment step for improving the quality of food processing residues for thermochemical and biochemical conversion.

  4. The use of a sequential extraction procedure for heavy metal analysis of house dusts by atomic absorption spectrometry.

    Science.gov (United States)

    Altundag, Huseyin; Dundar, Mustafa Sahin; Doganci, Secil; Celik, Muhammed; Tuzen, Mustafa

    2013-01-01

    In general, dust is considered as house or street dust. Indoor dust, as a contamination source, has been studied for many years. In this work, the original Community Bureau of Reference of the European Commission (BCR) three-stage sequential extraction procedure was applied to the fractionation of Cr, Cu, Fe, Mn, Pb, and Zn in 20 house dust samples from five different areas of Sakarya, Turkey. Acetic acid, hydroxylammonium chloride, and hydrogen peroxide plus ammonium acetate were used for the first, second, and third steps of the BCR method, respectively. The extracts were analyzed for the studied heavy metals using flame atomic absorption spectrometry. Validation of the results was performed by using a standard reference material (BCR 701 Sediment) to certify the experimental results obtained and to evaluate the reliability of the method used. The elemental loadings typically increased in magnitude according to the area order: Izmit Caddesi>Ankara Caddesi >Erenler>Karaman>Korucuk. The results were in agreement with values reported in the literature.

  5. Novel synergism by complex ligands in solvent extraction of rare earth metals(III) with {beta}-diketones

    Energy Technology Data Exchange (ETDEWEB)

    Imura, H. [Department of Environmental Sciences, Faculty of Science, Ibaraki University, Mito 310-8512 (Japan)]. E-mail: imura@mx.ibaraki.ac.jp; Ebisawa, M. [Department of Environmental Sciences, Faculty of Science, Ibaraki University, Mito 310-8512 (Japan); Kato, M. [Department of Environmental Sciences, Faculty of Science, Ibaraki University, Mito 310-8512 (Japan); Ohashi, K. [Department of Environmental Sciences, Faculty of Science, Ibaraki University, Mito 310-8512 (Japan)

    2006-02-09

    The extraction of rare earth metals(III) (RE) with hexafluoroacetylacetone (Hhfa) and 2-thenoyltrifluoroacetone (Htta) was studied in the presence of some cobalt(III) chelates such as tris(acetylacetonato)cobalt(III), tris(4-isopropyltropolonato)cobalt(III), tris(8-quinolinolato)cobalt(III), tris(8-quinolinethiolato)cobalt(III), and tris(diethyldithiocarbamato)cobalt(III) in benzene or toluene. The synergistic enhancement of the extraction of RE, especially of lanthanum(III) was found in all the systems. Therefore, those cobalt(III) chelates act as synergists or complex ligands. The equilibrium analysis and IR spectroscopic study were performed to evaluate the present synergistic mechanism. It was found that the RE-{beta}-diketone chelates form 1:1 adducts, i.e., binuclear complexes, with the cobalt(III) chelates in the organic phase. The formation constants ({beta} {sub s,1}) were determined and compared with those reported previously. The spectroscopic studies demonstrated that adducts have two different structures with inner- and outer-sphere coordination. In the former the cobalt(III) chelate directly coordinated to the RE ion and displaced the coordinated water molecules. In the latter the hydrogen-bonding was formed between the coordinating oxygen or sulfur atoms of cobalt(III) chelate and hydrogen atoms of the coordinated water molecules in the RE-{beta}-diketone chelate. The types of the adducts are mainly due to the steric factors of the RE-{beta}-diketone chelates and the cobalt(III) chelates.

  6. SEM based overlay measurement between resist and buried patterns

    Science.gov (United States)

    Inoue, Osamu; Okagawa, Yutaka; Hasumi, Kazuhisa; Shao, Chuanyu; Leray, Philippe; Lorusso, Gian; Baudemprez, Bart

    2016-03-01

    With the continuous shrink in pattern size and increased density, overlay control has become one of the most critical issues in semiconductor manufacturing. Recently, SEM based overlay of AEI (After Etch Inspection) wafer has been used for reference and optimization of optical overlay (both Image Based Overlay (IBO) and Diffraction Based Overlay (DBO)). Overlay measurement at AEI stage contributes monitor and forecast the yield after formation by etch and calibrate optical measurement tools. however those overlay value seems difficult directly for feedback to a scanner. Therefore, there is a clear need to have SEM based overlay measurements of ADI (After Develop Inspection) wafers in order to serve as reference for optical overlay and make necessary corrections before wafers go to etch. Furthermore, to make the corrections as accurate as possible, actual device like feature dimensions need to be measured post ADI. This device size measurement is very unique feature of CDSEM , which can be measured with smaller area. This is currently possible only with the CD-SEM. This device size measurement is very unique feature of CD-SEM , which can be measured with smaller area. In this study, we assess SEM based overlay measurement of ADI and AEI wafer by using a sample from an N10 process flow. First, we demonstrate SEM based overlay performance at AEI by using dual damascene process for Via 0 (V0) and metal 1 (M1) layer. We also discuss the overlay measurements between litho-etch-litho stages of a triple patterned M1 layer and double pattern V0. Second, to illustrate the complexities in image acquisition and measurement we will measure overlay between M1B resist and buried M1A-Hard mask trench. Finally, we will show how high accelerating voltage can detect buried pattern information by BSE (Back Scattering Electron). In this paper we discuss the merits of this method versus standard optical metrology based corrections.

  7. Detailed abundances in extremely metal poor dwarf stars extracted from SDSS

    CERN Document Server

    Sbordone, Luca; Caffau, Elisabetta; Ludwig, Hans-Gunther

    2012-01-01

    We report on the result of an ongoing campaign to determine chemical abundances in extremely metal poor (EMP) turn-off (TO) stars selected from the Sloan Digital Sky Survey (SDSS) low resolution spectra. This contribution focuses principally on the largest part of the sample (18 stars out of 29), observed with UVES@VLT and analyzed by means of the automatic abundance analysis code MyGIsFOS to derive atmosphere parameters and detailed compositions. The most significant findings include i) the detection of a C-rich, strongly Mg-enhanced star ([Mg/Fe]=1.45); ii) a group of Mn-rich stars ([Mn/Fe]>-0.4); iii) a group of Ni-rich stars ([Ni/Fe]>0.2). Li is measured in twelve stars, while for three upper limits are derived.

  8. Heavy Metals Extraction and Analysis in Aquatic Ecosystems with Automated Techniques

    Directory of Open Access Journals (Sweden)

    STROE, M.

    2009-06-01

    Full Text Available The proper choice of a measurement technique is only one step in the development of a successful application. All steps leading up to the measurement are equally important to the sampling and the sample preparation process begins at the point of collection and extends to the measurement step. The sample preparation method used to convert the sample into a form suitable for the measurement step can have a greater effect on the overall accuracy and reability of the results and the measurement itself. Sample preparation is one of the important problems in analytical process. The microwave digestion coupled with ICP MS measurements, for the heavy metals analysis is a very useful tools for the environmental samples.

  9. Selective dissolution followed by EDDS washing of an e-waste contaminated soil: Extraction efficiency, fate of residual metals, and impact on soil environment.

    Science.gov (United States)

    Beiyuan, Jingzi; Tsang, Daniel C W; Valix, Marjorie; Zhang, Weihua; Yang, Xin; Ok, Yong Sik; Li, Xiang-Dong

    2017-01-01

    To enhance extraction of strongly bound metals from oxide minerals and organic matter, this study examined the sequential use of reductants, oxidants, alkaline solvents and organic acids followed by a biodegradable chelating agent (EDDS, [S,S]-ethylene-diamine-disuccinic-acid) in a two-stage soil washing. The soil was contaminated by Cu, Zn, and Pb at an e-waste recycling site in Qingyuan city, China. In addition to extraction efficiency, this study also examined the fate of residual metals (e.g., leachability, bioaccessibility, and distribution) and the soil quality parameters (i.e., cytotoxicity, enzyme activities, and available nutrients). The reductants (dithionite-citrate-bicarbonate and hydroxylamine hydrochloride) effectively extracted metals by mineral dissolution, but elevated the leachability and bioaccessibility of metals due to the transformation from Fe/Mn oxides to labile fractions. Subsequent EDDS washing was found necessary to mitigate the residual risks. In comparison, prior washing by oxidants (persulphate, hypochlorite, and hydrogen peroxide) was marginally useful because of limited amount of soil organic matter. Prior washing by alkaline solvents (sodium hydroxide and sodium bicarbonate) was also ineffective due to metal precipitation. In contrast, prior washing by low-molecular-weight organic acids (citrate and oxalate) improved the extraction efficiency. Compared to hydroxylamine hydrochloride, citrate and oxalate induced lower cytotoxicity (Microtox) and allowed higher enzyme activities (dehydrogenase, acid phosphatase, and urease) and soil nutrients (available nitrogen and phosphorus), which would facilitate reuse of the treated soil. Therefore, while sequential washing proved to enhance extraction efficacy, the selection of chemical agents besides EDDS should also include the consideration of effects on metal leachability/bioaccessibility and soil quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. EVALUATION OF HEAVY METALS IN ETHANOLIC LEAF EXTRACT OF ACACIA CATECHU AS INDICATOR OF POLLUTION BY ATOMIC ABSORPTION SPECTROPHOTOMETRIC (FAAS ANALYSIS

    Directory of Open Access Journals (Sweden)

    Lakshmi.T

    2013-06-01

    Full Text Available Acacia catechu ethanolic leaf extract were selected to determine their heavy metals content and thereby to assure their safer therapeutic application. The trace and heavy metals were detected through atomic absorption spectrometry analysis. The selected medicinal plant material was procured from green chem herbal extracts, Bangalore, India and was digested with nitric acid and hydrochloric acid as specified. Absorbance was measured through atomic absorption spectrometer (AA 6030 and the concentration of different heavy metals in the plant sample was calculated. The quantitative determinations were carried out using standard calibration curve obtained by the standard solutions of different metals. The contents of heavy metals were found to be within the prescribed limit. Thus, on the basis of experimental outcome, it can be concluded that the plant material is safe and may not produce any harmful effect of metal toxicity during their therapeutic application. The investigated medicinal plants contains heavy metals such as arsenic (As, lead (Pb and mercury (Hg and cadmium (Cd, which were present within the permissible limit.

  11. Deep Extractive Desulfurization of Gasoline with Ionic Liquids Based on Metal Halide

    Institute of Scientific and Technical Information of China (English)

    Wang Haojie; He Jianxun; Yang Cairong; Zhang Hang

    2014-01-01

    Ionic liquid [Et3NH]Cl-FeCl3/CuCl was synthesized by mixing [Et3NH]Cl, anhydrous FeCl3 and anhydrous CuCl, and the desulfurization activity of this ionic liquid was tested. It exhibited remarkable ability in effective desulfurization of model gasoline (thiophene in n-octane) and lfuid catalytic cracking (FCC) gasoline, and the sulfur removal of thiophene in model oil (V(IL):V(oil)=0.08) could reach 93.9%in 50 min at 50℃. Low-sulfur (﹤10μg/g) FCC gasoline could be obtained after three extraction runs at an ionic liquid/oil volume ratio of 0.1, with the yield of FCC gasoline reaching 94.3%. The ionic liquid could be recycled 5 times with merely a slight decrease in activity.

  12. The immobilization of heavy metals in biosolids using phosphate amendments--comparison of EPA (6010 and 3051) and selective sequential extraction methods.

    Science.gov (United States)

    Song, Young Chae; Sivakumar, S; Nguyen, Tien Thanh; Kim, Soo-Hong; Kim, Boo Gil

    2009-08-15

    Biosolids are organic by-products from wastewater treatment plants that contain valuable nutrients but also represent a pollution problem. The amount of heavy metals in biosolids at high concentrations prevents their use as fertilizers. The aim of the present study is to immobilize heavy metals in biosolids using phosphate amendments. Analytical-grade potassium dihydrogenphosphate (KH(2)PO(4)) was used as the source of phosphate, and its ability to reduce heavy metals in biosolids (200 g) was evaluated according to five additional phosphate quantities: Control (C) (without phosphate), P1 (1.45 g), P2 (2.9 g), P3 (5.8 g), P4 (10.15 g), and P5 (14.5 g). The effect of phosphate treatments on metal extractability was evaluated using the selective sequential extraction (SSE) method, and total metal concentrations were analyzed by the (US Environmental Protection Agency) EPA 6010 and EPA 3051 methods. The total and extractable level of metals showed that Cu, Zn and Pb were the predominant elements in the biosolids analyzed in this study (control). SSE results showed that, on average, over 80% of the total metals present in the biosolids were found in the organic (F4) and residual (F5) fractions for Cu and Zn; Fe-Mn oxide (F3), organic (F4) and residual (F5) fractions for Cd; exchangeable (F1) and residual (F5) fractions for Pb; and exchangeable (F1), organic (F4) and residual (F5) fractions for Ni. The addition of phosphate substantially decreased the amount of metals (Cu, Zn, Cd, Pb, and Ni) in biosolids after a 10-day period; however, the amount of removal varied between the examined analytical techniques.

  13. Segmented Foil SEM Grids at Fermilab

    CERN Document Server

    Kopp, Sacha E; Childress, Sam; Ford, R; Harris, Debbie; Indurthy, Dharmaraj; Kendziora, Cary; Moore, Craig D; Pavlovich, Zarko; Proga, Marek; Tassotto, Gianni; Zwaska, Robert M

    2005-01-01

    We present recent beam data from a new design of a profile monitor for proton beams at Fermilab. The monitors, consisting of grids of segmented Ti foils 5micrometers thick, are secondary-electron emission monitors (SEM's). We review data on the device's precision on beam centroid position, beam width, and on beam loss associated with the SEM material placed in the beam.

  14. Ability of 3 extraction methods (BCR, Tessier and protease K) to estimate bioavailable metals in sediments from Huelva estuary (Southwestern Spain).

    Science.gov (United States)

    Rosado, Daniel; Usero, José; Morillo, José

    2016-01-15

    The bioavailable fraction of metals (Zn, Cu, Cd, Mn, Pb, Ni, Fe, and Cr) in sediments of the Huelva estuary and its littoral of influence has been estimated carrying out the most popular methods of sequential extraction (BCR and Tessier) and a biomimetic approach (protease K extraction). Results were compared to enrichment factors found in Arenicola marina. The linear correlation coefficients (R(2)) obtained between the fraction mobilized by the first step of the BCR sequential extraction, by the sum of the first and second steps of the Tessier sequential extraction, and by protease K, and enrichment factors in A. marina, are at their highest for protease K extraction (0.709), followed by BCR first step (0.507) and the sum of the first and second steps of Tessier (0.465). This observation suggests that protease K represents the bioavailable fraction more reliably than traditional methods (BCR and Tessier), which have a similar ability.

  15. Chemical and physiological metal bioaccessibility assessment in surface bottom sediments from the Deba River urban catchment: Harmonization of PBET, TCLP and BCR sequential extraction methods.

    Science.gov (United States)

    Unda-Calvo, Jessica; Martínez-Santos, Miren; Ruiz-Romera, Estilita

    2017-04-01

    In the present study, the physiologically based extraction test PBET (gastric and intestinal phases) and two chemical based extraction methods, the toxicity characteristic leaching procedure (TCLP) and the sequential extraction procedure BCR 701 (Community Bureau of Reference of the European Commission) have been used to estimate and evaluate the bioaccessibility of metals (Fe, Mn, Zn, Cu, Ni, Cr and Pb) in sediments from the Deba River urban catchment. The statistical analysis of data and comparison among physiological and chemical methods have highlighted the relevance of simulate the gastrointestinal tract environment since metal bioaccessibility seems to depend on water and sediment properties such as pH, redox potential and organic matter content, and, primordially, on the form in which metals are present in the sediment. Indeed, metals distributed among all fractions (Mn, Ni, Zn) were the most bioaccessible, followed by those predominantly bound to oxidizable fraction (Cu, Cr and Pb), especially near major urban areas. Finally, a toxicological risk assessment was also performed by determining the hazard quotient (HQ), which demonstrated that, although sediments from mid- and downstream sampling points presented the highest metal bioaccessibilities, were not enough to have adverse effects on human health, Cr being the most potentially toxic element. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Pyrometallurgical Extraction of Valuable Elements in Ni-Metal Hydride Battery Electrode Materials

    Science.gov (United States)

    Jiang, Yin-ju; Deng, Yong-chun; Bu, Wen-gang

    2015-10-01

    Gas selective reduction-oxidation (redox) and melting separation were consecutively applied to electrode materials of AB5-type Ni-metal hydride batteries leading to the production of a Ni-Co alloy and slag enriched with rare earth oxides (REO). In the selective redox process, electrode materials were treated with H2/H2O at 1073 K and 1173 K (800 °C and 900 °C). Active elements such as REs, Al, and Mn were oxidized whereas relatively inert elements such as Ni and Co were transformed into their elemental states in the treated materials. SiO2 and Al2O3 powders were added into the treated materials as fluxes which were then melted at 1823 K (1550 °C) to yield a Ni-Co alloy and a REO-SiO2-Al2O3-MnO slag. The high-purity Ni-Co alloy produced can be used as a raw material for AB5-type hydrogen-storage alloy. The REO content in slag was very high, i.e., 48.51 pct, therefore it can be used to recycle rare earth oxides.

  17. Determination of heavy metals and their speciation in street dusts by inductively coupled plasma-optical emission spectrometry after a Community Bureau of Reference sequential extraction procedure.

    Science.gov (United States)

    Altundag, Huseyin; Imamoglu, Mustafa; Doganci, Secil; Baysal, Erkan; Albayrak, Sinem; Tuzen, Mustafa

    2013-01-01

    Sequential selective extraction techniques are commonly used to fractionate the solid-phase forms of metals in soils. This procedure provides measurements of extractable metals from media, such as acetic acid (0.11 M), hydroxyl ammonium chloride (0.1 M), hydrogen peroxide (8.8 M) plus ammonium acetate (1 M), and aqua regia stages of the sequential extraction procedure. In this work, the extractable Pb, Cu, Mn, Sr, Ni, V, Fe, Zn, and Cr were evaluated in street dust samples from Sakarya, Turkey, between May and October 2009 using the three-step sequential extraction procedure described by the Community Bureau of Reference (BCR, now the Standards, Measurements, and Testing Programme) of the European Union. The sampling sites were divided into 10 categories; a total of 50 street dusts were analyzed. The determination of multielements in the samples was performed by inductively coupled plasma-optical emission spectrometry. Validation of the proposed method was performed using BCR 701 certified reference material. The results showed good agreement between the obtained and the certified values for the metals analyzed.

  18. Heavy metal pollution in topsoils near a cement plant: the role of organic matter and distance to the source to predict total and hcl-extracted heavy metal concentrations.

    Science.gov (United States)

    Bermudez, Gonzalo M A; Moreno, Mónica; Invernizzi, Rodrigo; Plá, Rita; Pignata, María Luisa

    2010-01-01

    Heavy metal and trace element concentrations were examined in topsoils to evaluate a cement plant and an industrial waste incinerator as pollution sources. As, Ba, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Se, Sm, Ta, Tb, Th, U, Yb and Zn were measured by Neutron Activation Analysis (NAA), and Co, Cu, Fe, Ni, Pb and Zn by a 0.5M-hydrochloric extraction technique using an Atomic Absorption Spectrophotometer (AAS). The Cr total concentration and HCl-extracted Co and Mn were possibly related to wind transportation from an industrial area in the north of Córdoba city (Argentina). Cu, Pb and Zn in partial HCl extraction were influenced by the cement plant and the industrial area in the north of Córdoba city. The mean total Ba concentration was above the residential and agricultural land use limits stated in national and international legislation and was related to the distance to the cement plant. The concentrations of HCl-extracted heavy metals could be predicted by the organic matter percentage and the distance to the cement plant (with R(2) values of 0.50-0.74). The Ca total concentration was seen to have little influence whereas the organic matter percentage strongly affected HCl-extracted heavy metals according to the correlation analysis and multiple regression models. According to soil quality guidelines for environmental health, the human and wildlife populations in Yocsina might be experiencing toxic Ba and Cr effects.

  19. Heavy metal extraction from produced water in the petroleum industry utilizing vegetal oil derivatives as the extractant; Extracao de metais pesados a partir de aguas produzidas na industria do petroleo utilizando derivados de oleo vegetal como extratante

    Energy Technology Data Exchange (ETDEWEB)

    Santana, Dulcineia de Castro [Centro Federal de Educacao Tecnologica de Goias (CEFET/GO), Goiania (Brazil). Coordenacao de Mineracao], e-mail: dcs@cefetgo.br, e-mail: dcs@eq.ufrn.br; Paulo, Joao Bosco de Araujo [Universidade Federal do Rio Grande do Norte (UFRN), Natal (Brazil). Centro de Tecnologia. Dept. de Engenharia Quimica], e-mail: jbosco@eq.ufrn.br; Lima, Raquel Franco de Souza [Universidade Federal do Rio Grande do Norte (UFRN), Natal (Brazil). Centro de Ciencias Exatas e da Terra. Dept. de Geologia], e-mail: raquel@geologia.ufrn.br; Brandao, Paulo Roberto Gomes [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Escola de Engenharia], e-mail: pbrandao@demin.ufmg.br; Fernandes Junior, Wilaci Eutropio [PETROBRAS, RN/CE (Brazil). Unidade de Negocio de Exploracao e Producao do Rio Grande do Norte e Ceara. Gerencia de Desenvolvimento da Producao], e-mail: wilaci@petrobras.com.br

    2007-12-15

    It is well known today that, although being a renewable resource, potable water could also be finite. In the environmental context, very often due to operational costs, the development of new water recycling techniques become significant when faced with the simple adaptation of effluent treatment before final disposal. Produced water comes from exploration operations and/or the production of oil and gas and is generally treated. Following the treatment, part of the produced water is recycled in secondary re-injection operations or steam generation. The remainder, which is the biggest amount, is expelled into the sea through underwater outlets. Millions of liters of water are expelled per day, containing heavy metals such as lead (Pb), cadmium (Cd) and nickel (Ni) in low concentrations. Some of this volume could be recycled for use in the irrigation of oleaginous cultures after this water has been given a suitable post-treatment. This treatment being specified in agreement with Class 3, of CONAMA Resolution No 357 (Brazil, 2005), which establishes the contents as <0,033 mg/L for Pb, <0,01 mg/L for Cd and <0,025 mg/L for Ni. Liquid-liquid extraction is a well known technology for the recovery of metals in aqueous mediums. This work studies the extraction of Pb, Cd, and Ni from a synthetic solution, using QAV solvent (aviation kerosene); and vegetal oil derivatives as the extractant. It is well known that vegetal oil derivatives have a strong complexation power on metals. A bench test basic investigation was made with the objective of studying the selectivity of coconut oil derivatives in the extraction of metals from synthetic solutions. The determination of the heavy metal concentrations in a complex matrix was made by using the atomic absorption spectrometry technique (AAS). The results of the preliminary experiments were promising. (author)

  20. An appraisal of conventional, microwave and ultrasound BCR extraction methods for the analysis of metals in sediments of Pančevo, Serbia

    Directory of Open Access Journals (Sweden)

    Relić D.

    2013-04-01

    Full Text Available We use conventional, microwave and ultrasound assisted sequential extraction, of defined time and power, techniques for extractions of Cd, Cu, Cr, Ni, Pb and Zn in sediments and certified material. We did not change the conditions of extractions through steps, cause we what to see is there difference in extraction results for the certified material and sediments. We use lower powers and time from microwave and ultrasound extraction in order to avoid additional heating and boiling of the samples. Steps 1–3 of the BCR (Community Bureau of Reference, excluding the hydrogen peroxide digestion in step 3, were completed in 16 h in the conventional, in 120 s with 90 W power of microwave and in 30 min of 42 kHz of an ultrasonic frequency. Digestion of organic matter with hydrogen peroxide was performed the same for all techniques. The fourth step, the pseudo-total content, was performed the same on samples remaining after performing the extraction of the previous three phases either conventionally, microwave-assisted or with ultrasound. The precision and accuracy of the proposed procedures were evaluated using a certified reference material BCR701. Acceptable accuracy for most of the metals was observed for all three steps of BCR protocol applying a 16 h total shaking period. Metals were determined with an acceptable accuracy after the pseudo-total step; expect Cr. Results obtained after the application of different techniques on sediments were comparable with ANOVA test for the 95 % of confidence level.

  1. Hexavalent chromium recovery by liquid–liquid extraction with 2-octylaminopyridine from acidic chloride media and its sequential separation from other heavy toxic metal ions

    Directory of Open Access Journals (Sweden)

    C.P. Mane

    2016-11-01

    Full Text Available A systematic study of extraction of chromium(VI with 2-octylaminopyridine (2-OAP in xylene at room temperature has been conducted. Quantitative extraction of chromium(VI was observed in the 0.4–0.8 M concentration range of hydrochloric acid. From the extracted complex species in the organic phase, chromium(VI was back extracted with 7 N ammonia (3 × 10 mL, and was determined by spectrophotometric method. Various parameters such as 2-OAP concentration, equilibrium period, effect of various diluents, aqueous: organic volume ratio, acidity and diverse ions were studied. The extraction reaction proceeds with ion-pair formation and the stoichiometry of extracted species was found to be [(2OAPH+ CrO3Cl−](org. The separation and determination of chromium(VI from associated and toxic metals in binary, ternary and multicomponent mixture were carried out. The method permits the sequential separation of chromium(VI from other toxic metals and has been used to separate and determine chromium(VI from alloys, and effluent water samples from tannery industries.

  2. Comparative evaluation of surface changes in four Ni-Ti instruments with successive uses - An SEM study

    Directory of Open Access Journals (Sweden)

    N Subha

    2011-01-01

    Full Text Available Aim: To evaluate the surface alterations seen in four kinds of Nickel-Titanium (Ni-Ti instruments using a scanning electron microscope (SEM for five successive uses in preparing root canals of extracted human molars and also to determine whether the design of the instrument influenced the appearance of defects on the instrument surface. Materials and Methods: Four different types of instruments namely; ProFile, ProTaper Rotary, ProTaper Hand and K3 Endo were used in 300 mesio-buccal canals. The instruments were examined under the SEM, after every use, to assess the progress of changes on their surfaces for a maximum of five uses. Statistical analysis used: Chi-square test. Results: The most prevalent defects observed were pitting, followed by metal strips. Signs of discontinuity, microfractures and disruption of cutting edge were also evident. Number of defects increased with successive uses. Conclusions: ProTaper Hand showed significantly more microfractures and metal strips than other instruments from third use onwards. ProTaper Rotary and K3 Endo also showed significant changes.

  3. Elastomer and resin replicas for sem observation of metallic materials

    OpenAIRE

    Palin-Luc, Thierry; Sellier, E.; D?Errico, F.; Vanhaeren, M.

    2002-01-01

    International audience; The replica technique is often used to study damage evolution at the surface of specimens or industrial components and understand the physicial phenomena responsible for fatigue crack initiation before failure. Replicas are usually made from acetate cellulose film. This paper presents an alternative technique generally used by archaeologists to study lithic use-wear and bone modification. A mold is made from a dental elastomer (silicon based impression material) and a ...

  4. +Facile extraction of azide in sartan drugs using magnetized anion-exchange metal-organic frameworks prior to ion chromatography.

    Science.gov (United States)

    Zhang, Sainan; Han, Peipei; Xia, Yan

    2017-09-08

    Quaternary amine functionalized metal-organic framework MIL-101(Cr) (MIL-101(Cr)-NMe3) was prepared as the sorbent for the magnetic solid-phase extraction (MSPE) of azide from sartan drugs before ion chromatography determination. Magnetization of MIL-101-NMe3 were achieved concurrently by adding MIL-101-NMe3 and Fe3O4@SiO2 to the sample solution under ultrasonication. The prepared Fe3O4@SiO2/MIL-101-NMe3 gave the adsorption capacity of 37.5mgg(-1). The developed method had a detection limit of 0.24μgL(-1) and quantitation limit of 0.79μgL(-1) for azide. The relative standard deviations for the intra-day retention time and peak area were 0.52% and 0.36% (n=5), respectively. The developed method was successfully applied for the determination of azide in sartan drugs with the recoveries from 96.5% to 100.5%. Copyright © 2017. Published by Elsevier B.V.

  5. Signal Feature Extraction and Quantitative Evaluation of Metal Magnetic Memory Testing for Oil Well Casing Based on Data Preprocessing Technique

    Directory of Open Access Journals (Sweden)

    Zhilin Liu

    2014-01-01

    Full Text Available Metal magnetic memory (MMM technique is an effective method to achieve the detection of stress concentration (SC zone for oil well casing. It can provide an early diagnosis of microdamages for preventive protection. MMM is a natural space domain signal which is weak and vulnerable to noise interference. So, it is difficult to achieve effective feature extraction of MMM signal especially under the hostile subsurface environment of high temperature, high pressure, high humidity, and multiple interfering sources. In this paper, a method of median filter preprocessing based on data preprocessing technique is proposed to eliminate the outliers point of MMM. And, based on wavelet transform (WT, the adaptive wavelet denoising method and data smoothing arithmetic are applied in testing the system of MMM. By using data preprocessing technique, the data are reserved and the noises of the signal are reduced. Therefore, the correct localization of SC zone can be achieved. In the meantime, characteristic parameters in new diagnostic approach are put forward to ensure the reliable determination of casing danger level through least squares support vector machine (LS-SVM and nonlinear quantitative mapping relationship. The effectiveness and feasibility of this method are verified through experiments.

  6. Leaching characteristics of arsenic and heavy metals in urban roadside soils using a simple bioavailability extraction test.

    Science.gov (United States)

    Wang, Xue-song; Qin, Yong; Chen, Yong-kang

    2007-06-01

    Regular ingestion of soils could pose a potential health threat due to long-term toxic element exposure. In order to estimate the human bioavailability quotients for As and heavy metals, 12 urban roadside soil samples were collected and analyzed for As, Pb, Cu, Zn, Ni, Co, and Cr using Simple Bioavailability Extraction Test (SBET). The quantities of As, Pb, Cu, Zn, Ni, Co, and Cr leached from soils within the simulated human stomach for 1 h indicated, on average, 27.3, 71.7, 40.4, 59.3, 17.7, 27.2 and 5.6% bioavailability, respectively. Significant positive correlations were observed between the amounts leached using SBET and the total amounts dissolved with HNO(3)-HCl-HF acid mixtures. Stepwise multiple regression analysis indicated that the amounts leached with SBET for As, Pb, Zn, Ni, and Co were not related to any of the physic-chemical parameters measured (i.e., soil texture, pH, total organic matter). These results may be valuable for providing input data for risk assessment at sites subject to anthropogenic soil contamination.

  7. SEM probe of IC radiation sensitivity

    Science.gov (United States)

    Gauthier, M. K.; Stanley, A. G.

    1979-01-01

    Scanning Electron Microscope (SEM) used to irradiate single integrated circuit (IC) subcomponent to test for radiation sensitivity can localize area of IC less than .03 by .03 mm for determination of exact location of radiation sensitive section.

  8. Does Sexually Explicit Media (SEM) Affect Me?

    DEFF Research Database (Denmark)

    Hald, Gert Martin; Træen, Bente; Noor, Syed W

    2015-01-01

    and understanding of one’s sexual orientation.First-person effects refer to self-perceived and self-reported effects of SEM consumptionas experienced by the consumer. In addition, the study examined and provided athorough validation of the psychometric properties of the seven-item PornographyConsumption Effect...... Scale (PCES). The study found that 93% of MSM reported smallto-largepositive effects from their SEM consumption on their sexual knowledge,enjoyment of and interest in sex, attitudes towards sex and understanding of theirsexual orientation. Only 7% reported any negative effects from their SEM......Using a self-selected online sample of 448 Norwegian men who have sex with men(MSM) and a cross-sectional design, the present study investigated first-person effectsof sexually explicit media (SEM) consumption on sexual knowledge, enjoyment of andinterest in sex, attitudes towards sex...

  9. A tomato stem cell extract, containing antioxidant compounds and metal chelating factors, protects skin cells from heavy metal-induced damages.

    Science.gov (United States)

    Tito, Annalisa; Carola, Antonietta; Bimonte, Marida; Barbulova, Ani; Arciello, Stefania; de Laurentiis, Francesco; Monoli, Irene; Hill, Jacqueline; Gibertoni, Simone; Colucci, Gabriella; Apone, Fabio

    2011-12-01

    Heavy metals can cause several genotoxic effects on cells, including oxidative stress, DNA sequence breakage and protein modification. Among the body organs, skin is certainly the most exposed to heavy metal stress and thus the most damaged by the toxic effects that these chemicals cause. Moreover, heavy metals, in particular nickel, can induce the over-expression of collagenases (enzymes responsible for collagen degradation), leading to weakening of the skin extracellular matrix. Plants have evolved sophisticated mechanisms to protect their cells from heavy metal toxicity, including the synthesis of metal chelating proteins and peptides, such as metallothioneins and phytochelatins (PC), which capture the metals and prevent the damages on the cellular structures. To protect human skin cells from heavy metal toxicity, we developed a new cosmetic active ingredient from Lycopersicon esculentum (tomato) cultured stem cells. This product, besides its high content of antioxidant compounds, contained PC, effective in the protection of skin cells towards heavy metal toxicity. We have demonstrated that this new product preserves nuclear DNA integrity from heavy metal damages, by inducing genes responsible for DNA repair and protection, and neutralizes the effect of heavy metals on collagen degradation, by inhibiting collagenase expression and inducing the synthesis of new collagen. © 2011 Arterra Bioscience srl. ICS © 2011 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  10. Detection of Coaxial Backscattered Electrons in SEM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    We present a coaxial detection of the backscattered electrons in SEM. The lens-aperture has been used to filter in energy and focus the backscattered electrons. This particular geometry allows us to eliminate the iow energy backscattered electrons and collect the backscattered electrons, which are backscattered close to the incident beam orientation. The main advantage of this geometry is adapted to topographic contrast attenuation and atomic number contrast enhancement. Thus this new SEM is very suitable to analyze the material composition.

  11. Microcircuit failure analysis using the SEM. [Scanning Electron Microscopes

    Science.gov (United States)

    Nicolas, D. P.

    1974-01-01

    The scanning electron microscope adds a new dimension to the knowledge that can be obtained from a failed microcircuit. When used with conventional techniques, SEM assists and clarifies the analysis, but it does not replace light microscopy. The most advantageous features for microcircuit analysis are long working distances and great depth of field. Manufacturer related failure modes of microcircuits are metallization defects, poor bonding, surface and particle contamination, and design and fabrication faults. User related failure modes are caused by abuse, such as overstress. The Physics of Failure Procedure followed by the Astrionics Laboratory in failure analysis is described, which is designed to obtain maximum information available from each step.

  12. Water stable metal-organic framework packed microcolumn for online sorptive extraction and direct analysis of naproxen and its metabolite from urine sample.

    Science.gov (United States)

    Hu, Yuling; Song, Chaoyong; Liao, Jia; Huang, Zelin; Li, Gongke

    2013-06-14

    The metal-organic framework MIL-101 was fabricated in a polyetheretherketone (PEEK) tube as micro-trapping device, and applied to sorptive extraction of naproxen and its metabolite in urine samples. The remarkable water stability of the MIL-101 characterizes the material as being different from other moisture sensitive metal-organic framework. It is therefore suitable for extraction of pharmaceuticals from biological fluids. The adsorption isotherms in aqueous solution showed that the adsorption of naproxen on MIL-101 is endothermic. Additionally, MIL-101 exhibited higher extraction capacity to naproxen than that of C18-bonded silica and multi-walled nanotube. A specially designed in-tube sorptive extraction (ITSE) device endows the extraction process with the characteristic of rapidness, convenience, and easy of conjunction with high performance liquid chromatography (HPLC). Finally the MIL-101 based ITSE method coupled with HPLC and fluorescence detection was applied to analysis of naproxen and 6-O-desmethylnaproxen in urine samples. Parameters that influence the online extraction procedure, including pH of the sample solution, flow rate of extraction, sample volume, desorption solvents and time were investigated. The method is proved to be highly sensitive with the linear range of 0.05-6.0μgL(-1) and the limits of detection of 0.034 and 0.011μgL(-1) for naproxen and 6-O-desmethylnaproxen, respectively. The recoveries in urine samples were 85.3-98.3% for naproxen and 94.0-97.3% for 6-O-desmethylnaproxen with intra- and inter-day RSDs of 2.7-5.2% and 7.1-8.1%, respectively. Urine samples could be directly subjected to analysis without any additional sample pretreatment. The proposed method was demonstrated an efficient, flexible and versatile extraction tool which is ideally suitable for online conjunction with chromatographic methods.

  13. Recent Progress in the Development of Supercritical Carbon Dioxide-Soluble Metal Ion Extractants: Aggregation, Extraction, and Solubility Properties of Silicon-Substituted Alkylenediphosphonic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, Mark L.; McAlister, Daniel R.; Stepinski, Dominique C.; Zalupski, Peter R.; Dzilawa, Julie A.; Barrans, Richard E.; Hess, J.N.; Rubas, Audris V.; Chiarizia, Renato; Lubbers, Christopher M.; Scurto, Aaron M.; Brennecke, Joan F.; Herlinger, Albert W.

    2003-09-11

    Partially esterified alkylenediphosphonic acids (DPAs) have been shown to be effective reagents for the extraction of actinide ions from acidic aqueous solution into conventional organic solvents. Efforts to employ these compounds in supercritical fluid extraction have been hampered by their modest solubility in unmodified supercritical carbon dioxide (SC-CO2). In an effort to design DPAs that are soluble in SC-CO2, a variety of silicon-substituted alkylenediphosphonic acids have been prepared and characterized, and their behavior compared with that of conventional alkyl-substituted reagents. Silicon substitution is shown to enhance the CO2-philicity of the reagents, while other structural features, in particular, the number of methylene groups bridging the phosphorus atoms of the extractant, are shown to exert a significant influence on their aggregation and extraction properties. The identification of DPAs combining desirable extraction properties with adequate solubility in SC-CO2 is shown to be facilitated by the application of molecular connectivity indices.

  14. Hybrid conducting polymer materials incorporating poly-oxo-metalates for extraction of actinides; Materiaux polymeres conducteurs hybrides incorporant des polyoxometallates pour l'extraction d'actinides

    Energy Technology Data Exchange (ETDEWEB)

    Racimor, D

    2003-09-15

    The preparation and characterization of hybrid conducting polymers incorporating poly-oxo-metalates for extracting actinides is discussed. A study of the coordination of various lanthanide cations (Ce(III), Ce(IV), Nd(III)) by the mono-vacant poly-oxo-metalate {alpha}{sub 2}-[P{sub 2}W{sub 17}O{sub 61}]{sup 10-} showed significant differences according to the cation.. Various {alpha}-A-[PW{sub 9}O{sub 34}(RPO){sub 2}]{sup 5-} hybrids were synthesized and their affinity for actinides or lanthanides was demonstrated through complexation. The first hybrid poly-oxo-metallic lanthanide complexes were then synthesized, as was the first hybrid functionalized with a pyrrole group. The electro-polymerization conditions of this pyrrole remain still to be optimized. Poly-pyrrole materials incorporating {alpha}{sub 2}-[P{sub 2}W{sub 17}O{sub 61}]{sup 10-} or its neodymium or cerium complexes as doping agents proved to be the first conducting polymer incorporating poly-oxo-metalates capable of extracting plutonium from nitric acid. (author)

  15. Comparison of the marginal microleakage in porcelain-fused-to-metal crown using different cements observed under SEM%应用扫描电镜对金属烤瓷冠不同粘接剂边缘微渗漏的比较研究

    Institute of Scientific and Technical Information of China (English)

    黄克强; 姜明欣; 李志刚; 李春山; 高秀秋

    2011-01-01

    目的:评价不同粘接剂粘固金属烤瓷冠的边缘微渗漏情况,为临床选择粘接剂提供实验依据.方法:选取传统的玻璃离子粘接剂、树脂加强型玻璃离子粘接剂、Panavia F粘接剂和Super-Bond C&B粘接剂4种材料,应用于离体牙金属烤瓷冠的粘接,用扫描电镜测量粘接剂与牙组织面间微缝隙的缝隙宽度.数据处理用SPSS 11.5软件包,其中组间比较采用方差分析.结果:玻璃离子粘接剂组界面缝隙宽度大于树脂加强玻璃离子组、Panavia F组和Super-Bond C&B组的宽度(P<0.01),树脂加强玻璃离子组界面缝隙宽度大于Panavia F组和Super-Bond C&B组的宽度(P<0.01),Panavia F组界面缝隙宽度大于Super-Bond C&B组的宽度(P<0.01).结论:树脂类粘接剂组的边缘微渗漏明显小于玻璃离子组,但树脂加强型玻璃离子的边缘微渗漏大于Panavia F和Super-Bond C&B组,在后两者中,从减小边缘微渗漏方面,Super-Bond C&B更具有优势.%Objective: To study the the marginal microleakage of metal crowns using four different cements by quantitative observation under SEM.Methods: Four different cements ( glass ionomer cement, resin-modified glass ionomer cement, Panavia F, Super- Bond C&B) were used to adhere Porcelain-Fused-to-metal crowns.The leakage width between the cement and the surface of teeth was observed under SEM.The statistical result was set by SPSS 11.5 and the data in 4 groups were compared by one-way analysis of variance.Results: The width were highly significant in glass ionomer cement group than that in the other three cements( P < 0.01 ).The width were highly significant in resin-modified glass ionomer cement group than that in Panavia F and Super-Bond C&B.The width were highly significant in Panavia F group than that in Super-Bond C&B( P <0.01 ).Conclusion: Adhesive resin luting system is better than glass ionomer cement at Porcelain-Fused-to-metal crown, Super-Bond C&B is better in decreasing marginal

  16. Simultaneously Extracted Metals/Acid-Volatile Sulfide and Total Metals in Surface Sediment from the Hanford Reach of the Columbia RIver and the Lower Snake River

    Energy Technology Data Exchange (ETDEWEB)

    Patton, Gregory W.; Crecelius, Eric A.

    2001-01-24

    Metals have been identified as contaminants of concern for the Hanford Reach because of upriver mining, industrial activities, and past nuclear material production at the US Department of Energy's Hanford Site. This study was undertaken to better understand the occurrence and fate of metals in sediment disposition areas in the Columbia and Snake Rivers.

  17. Characterization of soil heavy metal pools in paddy fields in Taiwan: chemical extraction and solid-solution partitioning

    NARCIS (Netherlands)

    Römkens, P.F.A.M.; Guo, H.Y.; Chu, C.L.; Liu, T.S.; Chiang, C.F.; Koopmans, G.F.

    2009-01-01

    Ongoing industrialization has resulted in an accumulation of metals like Cd, Cu, Cr, Ni, Zn, and Pb in paddy fields across Southeast Asia. Risks of metals in soils depend on soil properties and the availability of metals in soil. At present, however, limited information is available on how to measur

  18. On-line liquid phase micro-extraction based on drop-in-plug sequential injection lab-at-valve platform for metal determination

    Energy Technology Data Exchange (ETDEWEB)

    Mitani, Constantina [Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University, Thessaloniki 54124 (Greece); Anthemidis, Aristidis N., E-mail: anthemid@chem.auth.gr [Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University, Thessaloniki 54124 (Greece)

    2013-04-10

    Highlights: ► Drop-in-plug micro-extraction based on SI-LAV platform for metal preconcentration. ► Automatic liquid phase micro-extraction coupled with FAAS. ► Organic solvents with density higher than water are used. ► Lead determination in environmental water and urine samples. -- Abstract: A novel automatic on-line liquid phase micro-extraction method based on drop-in-plug sequential injection lab-at-valve (LAV) platform was proposed for metal preconcentration and determination. A flow-through micro-extraction chamber mounted at the selection valve was adopted without the need of sophisticated lab-on-valve components. Coupled to flame atomic absorption spectrometry (FAAS), the potential of this lab-at-valve scheme is demonstrated for trace lead determination in environmental and biological water samples. A hydrophobic complex of lead with ammonium pyrrolidine dithiocarbamate (APDC) was formed on-line and subsequently extracted into an 80 μL plug of chloroform. The extraction procedure was performed by forming micro-droplets of aqueous phase into the plug of the extractant. All critical parameters that affect the efficiency of the system were studied and optimized. The proposed method offered good performance characteristics and high preconcentration ratios. For 10 mL sample consumption an enhancement factor of 125 was obtained. The detection limit was 1.8 μg L{sup −1} and the precision expressed as relative standard deviation (RSD) at 50.0 μg L{sup −1} of lead was 2.9%. The proposed method was evaluated by analyzing certified reference materials and applied for lead determination in natural waters and urine samples.

  19. Environmental risk assessment of heavy metal extractability in a biosludge from the biological wastewater treatment plant of a pulp and paper mill.

    Science.gov (United States)

    Pöykiö, R; Nurmesniemi, H; Keiski, R L

    2007-05-01

    A five-stage sequential extraction procedure was used to fractionate heavy metals (Cd, Cu, Pb, Cr, Zn, Fe, Mn, Ni, Co, As, V and Ba) in a biosludge from the biological wastewater treatment plant of Stora Enso Oyj Veitsiluoto Mills at Kemi, Northern Finland, into the following fractions: (1) water-soluble fraction, (2) exchangeable fraction, (3) easily reduced fraction, (4) oxidizable fraction, and (5) residual fraction. The biosludge investigated in this study is a combination of sludge from the primary and secondary clarifiers at the biological wastewater treatment plant. Extraction stages (2)-(4) follow the protocol proposed by the Measurements and Testing Program (formerly BCR Programme) of the European Commission, which is based on acetic acid extraction (stage 2), hydroxylamine hydrochloride extraction (stage 3), and hydrogen peroxide digestion following the ammonium acetate extraction (stage 4). The residual fraction (stage 5) was based on digestion of the residue from stage 4 in a mixture of HF + HNO3 + HCl. Although metals were extractable in all fractions, the highest concentrations of most of the metals occurred in the residual fraction. From the environmental point of view, it was notable that the total heavy metal concentrations in the biosludge did not exceed the maximal allowable heavy metal concentrations for sewage sludge used in agriculture, set on the basis of environmental protection of soil by European Union Directive 86/278/EEC, and by the Finnish legislation. The Ca (98.6 g kg(-1); dry weight) and Mg (2.2 g kg(-1); dry weight) concentrations in the biosludge were 62 and 11 times higher than the typical values of 1.6 and of 0.2 g kg(-1) (dry weight), respectively, in arable land in Central Finland. The biosludge had a slightly alkaline pH ( approximately 8.30), a high loss-on-ignition value ( approximately 78%) and a liming effect of 10.3% expressed as Ca equivalents (dry weight). This indicates its potential as a soil conditioner and

  20. 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.

  1. 2-{[1-(3,4-Dihydroxyphenyl)methylidene]amino}benzoic acid immobilized Amberlite XAD-16 as metal extractant.

    Science.gov (United States)

    Venkatesh, Gopalan; Singh, Ajai K

    2005-07-15

    2-{[1-(3,4-Dihydroxyphenyl)methylidene]amino}benzoic acid (DMABA) was loaded on Amberlite XAD-16 (AXAD-16) via azo linker and the resulting resin AXAD-16-DMABA explored for enrichment of Zn(II), Mn(II), Ni(II), Pb(II), Cd(II), Cu(II), Fe(III) and Co(II). The optimum pH values for extraction are 6.5-7.0, 5.0-6.0, 5.5-7.5, 5.0-6.5, 6.5-8.0, 5.5-7.0, 4.0-5.0 and 6.0-7.0, respectively. The sorption capacity was found between 97 and 515mumolg(-1) and the preconcentration factors from 100 to 450. Tolerance limits for foreign species are reported. The kinetics of sorption is fast as t(1/2) is metal ion ions in river and synthetic water samples, Co in vitamin tablets and Zn in milk samples.

  2. Liquid-liquid extraction of metal ions, DFT and TD-DFT analysis of some 1,2,4-triazole Schiff Bases with high selectivity for Pb(II) and Fe(II)

    Science.gov (United States)

    Khoutoul, Mohamed; Lamsayah, Morad; Al-blewi, Fawzia F.; Rezki, Nadjet; Aouad, Mohamed Reda; Mouslim, Messali; Touzani, Rachid

    2016-06-01

    Liquid-liquid extraction of metal ions using some 1,2,4-triazole Schiff base derivatives as new extractants was studied. Fe2+, Zn2+, Cu2+, Co2+, Cd2+ and Pb2+ were extracted from the aqueous phase into the organic phase and the extractability for each metal ion was determined by atomic absorption. Interestingly, a competitive extraction was also investigated and then examined at different pH in order to explore the effect of the different substituent groups on metal extraction. Accordingly, high selectivity towards Fe2+ (90.1%) and Pb2+ (94.3%) provided respectively by the presence of electron withdrawing group and electron donor group was attained. In addition, geometry optimizations of the ground and excited-states of the ligands in order to get better insight into the geometry and the electronic structure were carried out by means of DFT and TD-DFT calculations.

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

    Directory of Open Access Journals (Sweden)

    Annibaldi A.

    2013-04-01

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

  4. Comparison between BCR sequential extraction and geo-accumulation method to evaluate metal mobility in sediments of Dongting Lake, Central China

    Science.gov (United States)

    Yao, Zhigang

    2008-02-01

    The form in which a metal exists strongly influences its mobility and thus, the effects on the environment. Operational methods of speciation analysis, such as the use of sequential extraction procedures, are commonly applied. The Dongting Lake, the second largest fresh-water lake in China, contains three China wetlands of international importance, the East Dongting Lake, South Dongting Lake, and West Dongting Lake. In this work, an optimized BCR sequential extraction procedure was used to assess the environmental risk of Cd, Cr, Cu, Ni, Pb and Zn in contaminated sediment of the Dongting Lake. The procedure was evaluated by using a certified reference material, BCR701. The results of the partitioning study indicated that in the lake sediments, more easily mobilized forms (acid exchangeable) were predominant for Cd, particularly in the samples from the East Dongting Lake. In contrast, the largest amount of Pb was associated with the iron and manganese oxide fractions and Cu, Zn, Cr, and Ni analyzed were mainly distributed in residual phase at an average percentage greater than 60% of the total metals. The potential risk to the lake’s water contamination was highest in the East Dongting Lake based on the calculated contamination factors. On the other hand, the total metal content was determined as well by inductively coupled plasma and mass spectrometry (ICP-MS) and assessed by using geo-accumulation index. The assessment results using geo-accumulation index were compared with the information on metal speciation. Both were correspondent with each other.

  5. Partial Least Squares Strukturgleichungsmodellierung (PLS-SEM)

    DEFF Research Database (Denmark)

    Hair, Joe F.; Hult, G. Thomas M.; Ringle, Christian M.

    (PLS-SEM) hat sich in der wirtschafts- und sozialwissenschaftlichen Forschung als geeignetes Verfahren zur Schätzung von Kausalmodellen behauptet. Dank der Anwenderfreundlichkeit des Verfahrens und der vorhandenen Software ist es inzwischen auch in der Praxis etabliert. Dieses Buch liefert eine...... anwendungsorientierte Einführung in die PLS-SEM. Der Fokus liegt auf den Grundlagen des Verfahrens und deren praktischer Umsetzung mit Hilfe der SmartPLS-Software. Das Konzept des Buches setzt dabei auf einfache Erläuterungen statistischer Ansätze und die anschauliche Darstellung zahlreicher Anwendungsbeispiele anhand...... einer einheitlichen Fallstudie. Viele Grafiken, Tabellen und Illustrationen erleichtern das Verständnis der PLS-SEM. Zudem werden dem Leser herunterladbare Datensätze, Aufgaben und weitere Fachartikel zur Vertiefung angeboten. Damit eignet sich das Buch hervorragend für Studierende, Forscher und...

  6. FIB-SEM tomography in biology.

    Science.gov (United States)

    Kizilyaprak, Caroline; Bittermann, Anne Greet; Daraspe, Jean; Humbel, Bruno M

    2014-01-01

    Three-dimensional information is much easier to understand than a set of two-dimensional images. Therefore a layman is thrilled by the pseudo-3D image taken in a scanning electron microscope (SEM) while, when seeing a transmission electron micrograph, his imagination is challenged. First approaches to gain insight in the third dimension were to make serial microtome sections of a region of interest (ROI) and then building a model of the object. Serial microtome sectioning is a tedious and skill-demanding work and therefore seldom done. In the last two decades with the increase of computer power, sophisticated display options, and the development of new instruments, an SEM with a built-in microtome as well as a focused ion beam scanning electron microscope (FIB-SEM), serial sectioning, and 3D analysis has become far easier and faster.Due to the relief like topology of the microtome trimmed block face of resin-embedded tissue, the ROI can be searched in the secondary electron mode, and at the selected spot, the ROI is prepared with the ion beam for 3D analysis. For FIB-SEM tomography, a thin slice is removed with the ion beam and the newly exposed face is imaged with the electron beam, usually by recording the backscattered electrons. The process, also called "slice and view," is repeated until the desired volume is imaged.As FIB-SEM allows 3D imaging of biological fine structure at high resolution of only small volumes, it is crucial to perform slice and view at carefully selected spots. Finding the region of interest is therefore a prerequisite for meaningful imaging. Thin layer plastification of biofilms offers direct access to the original sample surface and allows the selection of an ROI for site-specific FIB-SEM tomography just by its pronounced topographic features.

  7. Selective metal-ion extraction for multiple-ion liquid-liquid exchange reactions. Final report, June 1, 1979-May 31, 1982

    Energy Technology Data Exchange (ETDEWEB)

    Tavlarides, L.L.

    1982-01-29

    This research in hydrometallurgical solvent extraction is to develop a fundamental means to predict selectivity during simultaneous solvent extraction of multiple metal ions when the kinetic rates and thermodynamic equilibria both do not favor the desired metal. To this end the chemical kinetics and thermodynamic chemical equilibria models for the system copper-iron-acid sulfate solutions extracted by ..beta..-alkenyl-8-hydroxy quinoline in xylene are studied. These models can be employed with appropriate design equations to predict selectivity factors for two phase contactors. The work completed and in progress during the first half of the third funding period is on chemical equilibria studies for the iron-acid-sulfate-..beta..-alkenyl-8-hydroxy quinoline-xylene system. An aqueous phase ionic equilibrium model is available which can be used to calculate concentration of various Fe(III) ionic species present. Iron extraction data were obtained using both the AKUFVE, a high intensity stirrer with an in line centrifugal separator, and a shaker bath apparatus. Analysis of the data to determine a thermodynamic equilibrium model is in progress.

  8. Enhanced Retention of Chelating Reagents in Octadecylsilyl Silica Phase by Interaction with Residual Silanol Groups in Solid Phase Extraction of Divalent Metal Ions.

    Science.gov (United States)

    Ohmuro, Satoshi; Fujii, Kan; Yasui, Takashi; Takada, Kazutake; Yuchi, Akio; Kokusen, Hisao

    2016-01-01

    Solid-phase extraction (SPE) of divalent metal ions with a lipophilic and potentially divalent hexadentate chelating reagent (H2L), with which octadecylsilyl silica (ODS), was impregnated with was studied to gain more insight into and develop the potential of this methodology. This is the first time to demonstrate that this reagent as well as other common nitrogen-containing reagents were retained both by adsorption due to hydrogen bonding between nitrogen atoms of the reagent and residual silanol groups in the ODS phase and by simple distribution into the hydrophobic space. An appreciably large amount of this reagent could be retained by the adsorption mechanism even with a relatively thin loading solution. The divalent metal ions of Mn(2+), Co(2+) and Zn(2+) were extracted as 1:1 neutral complexes ([ML]), while Ni(2+) and Cu(2+) as ion-pairs of 1:1 cationic complex ([MHL](+)) with anion in SPE with H2L. The extractability and selectivity were substantially the same as that in liquid-liquid extraction.

  9. Reduction in oxidative stress levels in the colonic mucosa without fecal stream after the application of enemas containing aqueous Ilex paraguariensis extract Redução dos níveis de estresse oxidativo na mucosa cólica sem trânsito intestinal após aplicação de enemas contendo extrato aquoso de Ilex paraguariensis

    Directory of Open Access Journals (Sweden)

    Fernando Lorenzetti da Cunha

    2011-08-01

    Full Text Available PURPOSE: To evaluate the antioxidant effects of enemas containing aqueous extract of Ilex paraguariensis, comparing segments with and without fecal stream and correlating the segments with the duration of intervention. METHODS: Twenty-six Wistar rats were subjected to a diversion of the fecal stream in the left colon by a proximal colostomy and distal mucosal fistula. The rats were distributed randomly into two experimental groups of 13 animals each based on the time of sacrifice after surgical procedure (two or four weeks. Each group was then divided into two experimental subgroups that received either second daily enemas containing 0.9% saline solution or aqueous extract of Ilex paraguariensis at 0.2g/100g. Colitis was diagnosed by histopathological analysis and the detection of oxidative tissue damage by measuring the levels of malondialdehyde. The Mann-Whitney test was used to compare the tissue levels of malondialdehyde between colon segments with and without fecal stream in each experimental group, and the Kruskal-Wallis test was used to verify the variance between the levels of oxidative stress according the duration of the irrigation; both tests determined significance at 5% (pOBJETIVO: Avaliar os efeitos antioxidantes de clisteres contendo extrato aquoso de Ilex paraguariensis comparando segmentos com e sem trânsito fecal e correlacionando com o tempo de intervenção. MÉTODOS: Vinte e seis ratos Wistar machos foram submetidos à derivação do trânsito no cólon esquerdo pela confecção de colostomia proximal e fístula mucosa distal. Foram divididos de forma randomizada em dois grupos experimentais de 13 animais, de acordo com o sacrifício ser realizado após duas ou quatro semanas do procedimento cirúrgico. Cada grupo foi dividido em dois subgrupos experimentais segundo a aplicação diária ter sido realizada com enemas diários contendo solução fisiológica a 0,9% ou extrato aquoso de Ilex paraguariensis na concentra

  10. Bevalac extraction

    Energy Technology Data Exchange (ETDEWEB)

    Kalnins, J.G.; Krebs, G.; Tekawa, M.; Cowles, D.; Byrne, T.

    1992-02-01

    This report will describe some of the general features of the Bevatron extraction system, primarily the dependence of the beam parameters and extraction magnet currents on the Bevalac field. The extraction magnets considered are: PFW, XPl, XP2, XS1, XS2, XM1, XM2, XM3, XQ3A and X03B. This study is based on 84 past tunes (from 1987 to the present) of various ions (p,He,O,Ne,Si,S,Ar,Ca,Ti,Fe,Nb,La,Au and U), for Bevalac fields from 1.749 to 12.575 kG, where all tunes included a complete set of beam line wire chamber pictures. The circulating beam intensity inside the Bevalac is measured with Beam Induction Electrodes (BIE) in the South Tangent Tank. The extracted beam intensity is usually measured with the Secondary Emission Monitor (SEM) in the F1-Box. For most of the tunes the extraction efficiency, as given by the SEM/BIE ratio, was not recorded in the MCR Log Book, but plotting the available Log Book data as a function of the Bevalac field, see Fig.9, we find that the extraction efficiency is typically between 30->60% with feedback spill.

  11. Resistência à remoção por tração de coroas totais metálicas cimentadas em dentes com e sem reconstrução coronária Tensile strength of metal crowns cemented on dental and buildup surfaces

    Directory of Open Access Journals (Sweden)

    Eduardo Batista FRANCO

    1999-12-01

    Full Text Available O objetivo deste estudo foi verificar a resistência à remoção por tração de coroas totais metálicas cimentadas com o cimento de ionômero de vidro Ketac-Cem (ESPE em dentes adequadamente preparados, com e sem o pré-tratamento dentinário com o ácido poliacrílico a 40%, assim como sobre dentes previamente reconstruídos com o cimento ionomérico Vitremer (3M. Para efeito de comparação, empregou-se o cimento de fosfato de zinco (SS White. Foram selecionados 50 dentes humanos (primeiros pré-molares superiores sendo os mesmos fixados em bases cilíndricas de resina acrílica poliestirênica e divididos em 5 grupos de 10 elementos cada. Após a cimentação, os espécimes foram termociclados nas temperaturas de 5ºC, 37ºC e 55ºC e posteriormente acoplados à máquina de ensaios universal (Kratos, para a realização dos testes de resistência à tração. Os resultados obtidos foram submetidos a ANOVA, observando-se diferença estatística significante ao nível de 5% entre as diferentes condições estudadas. Com relação aos dentes sem reconstrução, verificou-se um resultado superior para o cimento Ketac-Cem quando da utilização do ácido poliacrílico. Para os grupos reconstruídos com o Vitremer, não observou-se diferença estatística significante entre os dois agentes cimentantes. A reconstrução coronária não prejudicou a retentividade das coroas totais metálicas.The purpose of this study was to evaluate the tensile strength of metal crowns cemented with Ketac-Cem (ESPE glass ionomer cement, on teeth properly prepared with and without previous treatment of 40% polyacrylic acid, as well as on built-up teeth reconstructed with Vitremer (3M ionomer cement. For comparison purposes, zinc phosphate cement (SS White was also employed. Fifty upper pre-molar human teeth were selected, embedded in epoxy resin, and divided into 5 groups of 10 elements each. After cementing, the specimens were submitted to thermocycling at 5

  12. Exploring metal detoxification and accumulation potential during vermicomposting of Tea factory coal ash: sequential extraction and fluorescence probe analysis

    Science.gov (United States)

    Goswami, Linee; Pratihar, Sanjay; Dasgupta, Suman; Bhattacharyya, Pradip; Mudoi, Pronab; Bora, Jayanta; Bhattacharya, Satya Sundar; Kim, Ki Hyun

    2016-07-01

    Metal contamination from coal ashes (CAs) is widely recognized as a significant environmental concern. To learn more about metal detoxification and accumulation potential of earthworm species, metal-rich tea factory coal ashes (TFCA) were fed to Eisenia fetida and Lampito mauritii by employing a fluorescent tag detection method. Fascinatingly, on feeding fluorescence probed Zn and Cd along with cow dung to Eisenia fetida, the detection of the gut-proteins with a molecular mass higher than 100 kDa was a distinct evidence of metal binding. Significant increases were observed in the content of humified organic C [humic acid (HAC) and fulvic acid C (FAC)] and degree of humification during vermicomposting. Concurrently, considerably large amount of toxic metals (Cr, Cd, Pb, and Zn) was transformed from exchangeable to recalcitrant (organic matter and mineral bound) fractions. Moreover, total metal concentrations were reduced with high removal efficiency upon vermicomposting.

  13. Exploring metal detoxification and accumulation potential during vermicomposting of Tea factory coal ash: sequential extraction and fluorescence probe analysis

    Science.gov (United States)

    Goswami, Linee; Pratihar, Sanjay; Dasgupta, Suman; Bhattacharyya, Pradip; Mudoi, Pronab; Bora, Jayanta; Bhattacharya, Satya Sundar; Kim, Ki Hyun

    2016-01-01

    Metal contamination from coal ashes (CAs) is widely recognized as a significant environmental concern. To learn more about metal detoxification and accumulation potential of earthworm species, metal-rich tea factory coal ashes (TFCA) were fed to Eisenia fetida and Lampito mauritii by employing a fluorescent tag detection method. Fascinatingly, on feeding fluorescence probed Zn and Cd along with cow dung to Eisenia fetida, the detection of the gut-proteins with a molecular mass higher than 100 kDa was a distinct evidence of metal binding. Significant increases were observed in the content of humified organic C [humic acid (HAC) and fulvic acid C (FAC)] and degree of humification during vermicomposting. Concurrently, considerably large amount of toxic metals (Cr, Cd, Pb, and Zn) was transformed from exchangeable to recalcitrant (organic matter and mineral bound) fractions. Moreover, total metal concentrations were reduced with high removal efficiency upon vermicomposting. PMID:27456167

  14. Comparative study of the fate and mobility of metals discharged in mining and urban effluents using sequential extractions on suspended solids.

    Science.gov (United States)

    Gagnon, Christian; Turcotte, Patrice; Vigneault, Bernard

    2009-12-01

    The fate, bioavailability and environmental impacts of metals discharged in municipal and mining wastewater discharge will depend to a large extent on chemical speciation and distribution. Previous studies on metal bioaccumulation have shown that total metal concentrations are not a good predictor of bioavailability in the dispersion plumes of municipal effluents. The objective of this study was to determine the solid phase speciation of metals in surface waters receiving urban and mining effluents in order to assess their fate and relative mobility in the receiving environment. Suspended particulate matter was sampled using sediment traps at several sites downstream of effluent outfall plumes as well as at reference upstream sites. Particulate metal in operationally defined fractions--exchangeable/carbonates, reducible, oxidisable and residual--were determined in suspended particulate matter with a series of selective chemical extractions. Metal enrichment in suspended particles was generally observed in both mining and urban effluent discharges. When compared to its receiving environment, the mining effluent appeared to release more particulate metals (Cu, Fe, Zn) in the most reactive fractions (i.e. exchangeable/carbonates + reducible forms, 23-43%), while other released metals, such as Cd and Mn, were predominantly in the least reactive forms (i.e., oxidisable + residual, 73-97%). In contrast, the reactivity of all particulate metals, with the exception of Mn, from the urban effluent was much higher, with up to 65, 42, 30 and 43% for Cd, Cu, Fe and Zn, respectively, in the two most reactive fractions. As expected in effluent dispersion plumes, parameters such as the organic carbon, Fe oxide and carbonate contents have specific effects on the partitioning of several trace metals, particularly Cd, Cu and Zn. Our results indicated that the relative distributions of metals among geochemical fractions varied in the effluent receiving waters where organic carbon and

  15. Search Engine Marketing (SEM: Financial & Competitive Advantages of an Effective Hotel SEM Strategy

    Directory of Open Access Journals (Sweden)

    Leora Halpern Lanz

    2015-05-01

    Full Text Available Search Engine Marketing and Optimization (SEO, SEM are keystones of a hotels marketing strategy, in fact research shows that 90% of travelers start their vacation planning with a Google search. Learn five strategies that can enhance a hotels SEO and SEM strategies to boost bookings.

  16. METROLOGICAL PERFORMANCE OF SEM 3D TECHNIQUES

    DEFF Research Database (Denmark)

    Marinello, Francesco; Carmignato, Simone; Savio, Enrico;

    2008-01-01

    This paper addresses the metrological performance of three-dimensional measurements performed with Scanning Electron Microscopes (SEMs) using reconstruction of surface topography through stereo-photogrammetry. Reconstruction is based on the model function introduced by Piazzesi adapted for eucent...... condition are studied, in order to define a strategy to optimise the measurements taking account of the critical factors in SEM 3D reconstruction. Investigations were performed on a novel sample, specifically developed and implemented for the tests.......This paper addresses the metrological performance of three-dimensional measurements performed with Scanning Electron Microscopes (SEMs) using reconstruction of surface topography through stereo-photogrammetry. Reconstruction is based on the model function introduced by Piazzesi adapted...... and the instrument set-up; the second concerns the quality of scanned images and represents the major criticality in the application of SEMs for 3D characterizations. In particular the critical role played by the tilting angle and its relative uncertainty, the magnification and the deviations from the eucentricity...

  17. Building a SEM Analytics Reporting Portfolio

    Science.gov (United States)

    Goff, Jay W.; Williams, Brian G.; Kilgore, Wendy

    2016-01-01

    Effective strategic enrollment management (SEM) efforts require vast amounts of internal and external data to ensure that meaningful reporting and analysis systems can assist managers in decision making. A wide range of information is integral for leading effective and efficient student recruitment and retention programs. This article is designed…

  18. Building a SEM Analytics Reporting Portfolio

    Science.gov (United States)

    Goff, Jay W.; Williams, Brian G.; Kilgore, Wendy

    2016-01-01

    Effective strategic enrollment management (SEM) efforts require vast amounts of internal and external data to ensure that meaningful reporting and analysis systems can assist managers in decision making. A wide range of information is integral for leading effective and efficient student recruitment and retention programs. This article is designed…

  19. Comparing SVARs and SEMs : more shocking stories

    NARCIS (Netherlands)

    Jacobs, Jan; Wallis, Kenneth F.

    2002-01-01

    The structural vector autoregression (SVAR) and simultaneous equation macroeconometric model (SEM) styles of empirical macroeconomic modelling are compared and contrasted, with reference to two models of the UK economy, namely the Cambridge long-run structural VAR model and the COMPACT model.

  20. Evaluation of the bioaccessible gastric and intestinal fractions of heavy metals in contaminated soils by means of a simple bioaccessibility extraction test.

    Science.gov (United States)

    Jorge Mendoza, C; Tatiana Garrido, R; Cristian Quilodrán, R; Matías Segovia, C; José Parada, A

    2017-06-01

    A study is made to evaluate the bioaccessibility of heavy metals in contaminated soils through a simple bioaccessibility extraction test (SBET), applied to the analysis of both the gastric and intestinal phases. Soils with high metal content of the Mapocho, Cachapoal, and Rancagua series were studied; they are located in suburban areas of large cities in the central valley of Chile. The bioaccessible concentrations of Cd, Cr, Cu, Ni, Pb, and Zn were related to the main physicochemical characteristics of the soils and to the chemical forms obtained by sequential extraction. The elements Cd, Cu, Ni, and Zn are distributed in the soils between the exchangeable fractions, bound to oxides, to organic matter, and in the residual fraction. On the other hand, Cr and Pb are found mainly in the fractions bound to organic matter and in the residual fraction. The three soils have a high Cu content, (640-2060 mg/kg), in the order Cachapoal > Rancagua > Mapocho. The SBET test allowed establishing a different bioaccessibility for the elements in the soil. Cu was notoriously bioaccessible in both the gastric and intestinal phases in the three soils, reaching more than 50% in the Cachapoal and Rancagua soils. The other elements, regardless of the soil, were bioaccessible only in one of the phases, more frequently in the gastric phase. The multiple correlation study indicates that the metal forms have a higher incidence than the soil's physicochemical factors on the extractability to evaluate the human oral bioaccessibility of the metals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Simultaneous detection of trace metal ions in water by solid phase extraction spectroscopy combined with multivariate calibration.

    Science.gov (United States)

    Wang, Lei; Cao, Peng; Li, Wei; Tong, Peijin; Zhang, Xiaofang; Du, Yiping

    2016-04-15

    Solid Phase Extraction Spectroscopy (SPES) developed in this paper is a technique to measure spectrum directly on the solid phase material where the analytes are concentrated in SPE process. Membrane enrichment and UV-Visible spectroscopy were utilized to fulfill SPES, and multivariate calibration method of partial least squares (PLS) was used to simultaneously detect the concentrations of trace cobalt (II) and zinc (II) in water samples. The proposed method is simple, sensitive and selective. The complexes of analyte ions were collected on the cellulose acetate membranes via membrane filtration after the complexation reaction with 1-2-pyridylazo 2-naphthol (PAN). The spectra of the membranes which contained the complexes of metal ions and PAN were measured directly without eluting. The analytical conditions including pH, reaction time, sample volume, the amount of PAN, and flow rates were optimized. Nonionic surfactant Brij-30 was absorbed on the membranes prior to SPES to modify the membranes for improving the enrichment and spectrum measurement. The interference from other ions to the determination was investigated. Under the optimal condition, the absorbance was linearly related to the concentration at the range of 0.1-3.0 μg/L and 0.1-2.0 μg/L, with the correlation coefficients (R(2)) of 0.9977 and 0.9951 for Co (II) and Zn (II), respectively. The limits of detection were 0.066 μg/L for cobalt (II) and 0.104 μg/L for zinc (II). PLS regression with leave-one-out cross-validation was utilized to build models to detect cobalt (II) and zinc (II) in drinking water samples simultaneously. The correlation coefficient between ion concentration and spectrum of calibration set and independent prediction set were 1.0000 and 0.9974 for cobalt (II) and 1.0000 and 0.9956 for zinc (II). For cobalt (II) and zinc (II), the errors of the prediction set were in the range 0.0406-0.1353 μg/L and 0.0025-0.1884 μg/L. Copyright © 2016. Published by Elsevier B.V.

  2. THE IMPORTANCE OF ORGANIC MATTER DISTRIBUTION AND EXTRACT SOIL:SOLUTION RATIO ON THE DESORPTION OF HEAVY METALS FROM SOILS

    Science.gov (United States)

    The lability (mobility and bioavailability) of metals varies significantly with soil properties for similar total soil metal concentrations. We studied desorption of Cu, Ni and Zn, from 15 diverse, unamended soils. These studies included evaluation of the effects of soil:solution...

  3. A high-throughput solid-phase extraction microchip combined with inductively coupled plasma-mass spectrometry for rapid determination of trace heavy metals in natural water.

    Science.gov (United States)

    Shih, Tsung-Ting; Hsieh, Cheng-Chuan; Luo, Yu-Ting; Su, Yi-An; Chen, Ping-Hung; Chuang, Yu-Chen; Sun, Yuh-Chang

    2016-04-15

    Herein, a hyphenated system combining a high-throughput solid-phase extraction (htSPE) microchip with inductively coupled plasma-mass spectrometry (ICP-MS) for rapid determination of trace heavy metals was developed. Rather than performing multiple analyses in parallel for the enhancement of analytical throughput, we improved the processing speed for individual samples by increasing the operation flow rate during SPE procedures. To this end, an innovative device combining a micromixer and a multi-channeled extraction unit was designed. Furthermore, a programmable valve manifold was used to interface the developed microchip and ICP-MS instrumentation in order to fully automate the system, leading to a dramatic reduction in operation time and human error. Under the optimized operation conditions for the established system, detection limits of 1.64-42.54 ng L(-1) for the analyte ions were achieved. Validation procedures demonstrated that the developed method could be satisfactorily applied to the determination of trace heavy metals in natural water. Each analysis could be readily accomplished within just 186 s using the established system. This represents, to the best of our knowledge, an unprecedented speed for the analysis of trace heavy metal ions. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Tillandsia stricta Sol (Bromeliaceae) leaves as monitors of airborne particulate matter-A comparative SEM methods evaluation: Unveiling an accurate and odd HP-SEM method.

    Science.gov (United States)

    de Oliveira, Martha Lima; de Melo, Edésio José Tenório; Miguens, Flávio Costa

    2016-09-01

    Airborne particulate matter (PM) has been included among the most important air pollutants by governmental environment agencies and academy researchers. The use of terrestrial plants for monitoring PM has been widely accepted, particularly when it is coupled with SEM/EDS. Herein, Tillandsia stricta leaves were used as monitors of PM, focusing on a comparative evaluation of Environmental SEM (ESEM) and High-Pressure SEM (HPSEM). In addition, specimens air-dried at formaldehyde atmosphere (AD/FA) were introduced as an SEM procedure. Hydrated specimen observation by ESEM was the best way to get information from T. stricta leaves. If any artifacts were introduced by AD/FA, they were indiscernible from those caused by CPD. Leaf anatomy was always well preserved. PM density was determined on adaxial and abaxial leaf epidermis for each of the SEM proceedings. When compared with ESEM, particle extraction varied from 0 to 20% in air-dried leaves while 23-78% of particles deposited on leaves surfaces were extracted by CPD procedures. ESEM was obviously the best choice over other methods but morphological artifacts increased in function of operation time while HPSEM operation time was without limit. AD/FA avoided the shrinkage observed in the air-dried leaves and particle extraction was low when compared with CPD. Structural and particle density results suggest AD/FA as an important methodological approach to air pollution biomonitoring that can be widely used in all electron microscopy labs. Otherwise, previous PM assessments using terrestrial plants as biomonitors and performed by conventional SEM could have underestimated airborne particulate matter concentration.

  5. Bases de Datos Semánticas

    Directory of Open Access Journals (Sweden)

    Irving Caro Fierros

    2016-12-01

    Full Text Available En 1992, cuando Tim Berners-Lee dio a conocer la primera  versión  de  la  Web,  su  visión  a  futuro  era  incorporar metadatos  con  información  semántica  en  las  páginas  Web.  Es precisamente   a   principios   de   este   siglo   que   inicia   el   auge repentino  de  la  Web  semántica  en  el  ambiente  académico  e Internet. El modelo de datos semántico se define como un modelo conceptual que permite definir el significado de los datos a través de  sus  relaciones  con  otros.  En  este  sentido,  el  formato  de representación  de  los  datos  es  fundamental  para  proporcionar información de carácter semántico. La tecnología enfocada en las bases de datos semánticas se encuentra actualmente en un punto de  inflexión,  al  pasar  del  ámbito  académico  y  de  investigación  a ser una opción comercial completa. En este artículo se realiza un análisis  del  concepto  de  base  de  datos  semántica.  También  se presenta  un  caso  de  estudio  donde  se  ejemplifican  operaciones básicas  que  involucran  la  gestión  de  la  información  almacenada en este tipo de base de datos.

  6. Marginal integrity of class V restorations: SEM versus dye penetration.

    Science.gov (United States)

    Ernst, Claus-Peter; Galler, Pia; Willershausen, Brita; Haller, Bernd

    2008-03-01

    To perform an in vitro investigation on the marginal integrity of different adhesives (Optibond FL, Scotchbond 1XT, Clearfil SE Bond, Adper Prompt L-Pop, S(3) Bond, iBond exp., Adper Prompt L-Pop) in combination with Tetric Ceram as well as an experimental silorane-restorative (Hermes, Hermes Bond; 3M ESPE) using SEM and dye penetration (2% methylene blue) in a comparative manner. Standardized class V-cavities (3 mm x 1.5 mm) were prepared in 70 extracted human teeth (n=10). The adhesives were applied according to manufacturers' instructions. The cavities were restored with three increments. After finishing and polishing (Sof-Lex discs) and thermocycling (5000x, 5/55 degrees C), replicas were taken and the teeth immersed in the dye for 10s (D10) and evaluated. After another penetration of 30 min (D30) a final evaluation of the percentage of dye-penetrated margins was conducted. The median percentages in marginal gaps (%) at the enamel margins for the three methods investigated (D10/D30/SEM) were--Optibond FL: 0/0/4, Scotchbond 1 XT: 5/16/11, Clearfil SE Bond: 0/0/0, S(3) Bond: 0/0/1, iBond exp.: 20/42/12, Adper Prompt L-Pop: 5/23/8, Hermes/Hermes Bond: 5/45/24. Cementum margins--Optibond FL: 0/1/0, Scotchbond 1 XT: 0/21/23, Clearfil SE Bond: 0/0/4, S(3) Bond: 0/0/0, iBond exp.: 0/0/0, Adper Prompt L-Pop: 10/32/23, Hermes/Hermes Bond: 0/0/13. After pooling the data of all groups, a Spearmann's rho test showed a good correlation between the methods D10 and D30 at the enamel margins and at the entire cavity margins (correlation coefficient 0.8 and 0.7). SEM did not correlate with the results obtained from D10 (correlation coefficient <0.5). A fair correlation was found between SEM and D30 for the entire cavity margin but a good correlation for the enamel margins. No correlation between investigation methods was determined at the cementum margins. D30 showed a better correlation to SEM than D10 did. Therefore, 30 min of dye penetration time seems to be more suitable

  7. Method validation for determination of metals in Vitis labrusca L. grapevine leaf extracts by inductively coupled plasma mass spectrometry (ICP-MS

    Directory of Open Access Journals (Sweden)

    LIANE V.V. BOKOWSKI

    Full Text Available ABSTRACT Vitis labrusca L. is the main species used for wine and juice production in Brazil. The grapevine leaves can be used both as functional foods and as cheapest sources for the extraction of phenolic compounds. Besides the antioxidant activity, grapevine leaves exhibited significant anti-inflammatory activity. Therefore, the aim of this study was to develop and validate an analytical methodology to determine the metals selenium (96Se, chromium (53Cr, nickel (62Ni, cadmium (111Cd and lead (206Pb in 30 samples of grapevine leaf extracts (Vitis labrusca, Bordo cultivar using inductively coupled plasma mass spectrometry (ICP-MS. To obtain the grapevine leaf extracts the samples were milled, weighed and digested in microwave oven with nitric acid. The method showed linearity, precision, accuracy and limits of quantification and detection acceptable for INMETRO protocol validation of analytical methods. Therefore, the method using ICP-MS was developed and validated to determine metals concentrations in grapevine leaves of Vitis labrusca L. and the proposed method could be applied in routine analytical laboratory.

  8. Synthesis and Characterization of Polystyrene-Supported Piperazine-Substituted Triazoles by CuAAC and First Evaluation for Metal Ion Extraction

    Directory of Open Access Journals (Sweden)

    Riadh Slimi

    2016-05-01

    Full Text Available The goal of this work was to synthesize substituted polystyrene for metal extraction and/or depollution by introduction of substituted piperazines as chelatants starting from Merrifield polymer. After transformation of Merrifield’s resin in azidomethyl polystyrene, click-chemistry using copper (I-catalyzed Huisgen’s reaction (CuAAC was performed to prepare different polymers grafted with 1,4-triazoles bearing the piperazines, containing an alkyne as the other counterpart in the CuAAC. The polymers were then first tested for their efficiency to remove various metal ions from neutral aqueous solutions (Fe3+, Ni2+, Cu2+, Zn2+ and Pb2+. The polymers were found to extract Ni2+ and Zn2+ with low efficiencies ≤40%. For Fe3+ and Cu2+, the average extraction was around 80%, and for Pb2+ around 50%. The global selectivity for these polymers was found to be in the order of Fe3+ ≥ Cu2+ > Pb2+ >> Ni2+ > Zn2+.

  9. Comprehensive simulation of SEM images taking into account local and global electromagnetic fields

    Science.gov (United States)

    Babin, Sergey; Borisov, Sergey S.; Ito, Hiroyuki; Ivanchikov, Andrei; Matison, Dmitri; Militsin, Vladimir; Suzuki, Makoto

    2010-06-01

    We are reporting the development of a simulation tool with unique capabilities to comprehensively model an SEM signal. This includes electron scattering, charging, and detector settings, as well as modeling of the local and global electromagnetic fields and the electron trajectories in these fields. Experimental and simulated results were compared for SEM imaging of carbon nanofibers embedded into bulk material in the presence of significant charging, as well as for samples with applied potential on metal electrodes. The effect of the potentials applied to electrodes on the secondary emission was studied; the resulting SEM images were simulated. The image contrast depends strongly on the sign and the value of the potential. SEM imaging of nanofibers embedded into silicon dioxide resulted in the considerable change of the appeared dimensions of the fibers and as well as tone reversal when the beam voltage was varied. The results of the simulations are in agreement with experimental results.

  10. Seafloor earthquake measurement system, SEMS IV

    Energy Technology Data Exchange (ETDEWEB)

    Platzbecker, M.R.; Ehasz, J.P.; Franco, R.J.

    1997-07-01

    Staff of the Telemetry Technology Development Department (2664) have, in support of the U.S. Interior Department Mineral Management Services (MMS), developed and deployed the Seafloor Earthquake Measurement System IV (SEMS IV). The result of this development project is a series of three fully operational seafloor seismic monitor systems located at offshore platforms: Eureka, Grace, and Irene. The instrument probes are embedded from three to seven feet into the seafloor and hardwired to seismic data recorders installed top side at the offshore platforms. The probes and underwater cables were designed to survive the seafloor environment with an operation life of five years. The units have been operational for two years and have produced recordings of several minor earthquakes in that time. Sandia Labs will transfer operation of SEMS IV to MMS contractors in the coming months. 29 figs., 25 tabs.

  11. SEM investigation of heart tissue samples

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, R; Amoroso, M [Physics Department, University of the West Indies, St. Augustine, Trinidad and Tobago, West Indies (Trinidad and Tobago)

    2010-07-01

    We used the scanning electron microscope to examine the cardiac tissue of a cow (Bos taurus), a pig (Sus scrofa), and a human (Homo sapiens). 1mm{sup 3} blocks of left ventricular tissue were prepared for SEM scanning by fixing in 96% ethanol followed by critical point drying (cryofixation), then sputter-coating with gold. The typical ridged structure of the myofibrils was observed for all the species. In addition crystal like structures were found in one of the samples of the heart tissue of the pig. These structures were investigated further using an EDVAC x-ray analysis attachment to the SEM. Elemental x-ray analysis showed highest peaks occurred for gold, followed by carbon, oxygen, magnesium and potassium. As the samples were coated with gold for conductivity, this highest peak is expected. Much lower peaks at carbon, oxygen, magnesium and potassium suggest that a cystallized salt such as a carbonate was present in the tissue before sacrifice.

  12. Sem-observation of developing plant organs using deep-frozen specimens

    NARCIS (Netherlands)

    NN,

    1982-01-01

    The SEM-observation of plant material normally requires dehydrated, dry specimens coated with carbon or metal. Unfortunately, the standard drying methods (including the critical-point-drying-technique) often cause shrinking and deformation of the specimen surface; therefore, SEMstudies on plant onto

  13. Phase-selective chemical extraction of selenium and sulfur from nanoscale metal chalcogenides: a general strategy for synthesis, purification, and phase targeting.

    Science.gov (United States)

    Sines, Ian T; Schaak, Raymond E

    2011-02-09

    Controlling the composition and phase formation of bulk and nanoscale solids underpins efforts to control physical properties. Here, we introduce a powerful new chemical pathway that facilitates composition-tunable synthesis, post-synthesis purification, and precise phase targeting in metal chalcogenide systems. When metal selenides and sulfides react with trioctylphosphine (TOP) at temperatures that range from 65 to 270 °C, selenium and sulfur are selectively extracted to produce the most metal-rich chalcogenide that is stable in a particular binary system. This general approach is demonstrated for SnSe(2), FeS(2), NiSe(2), and CoSe(2), which convert to SnSe, FeS, Ni(3)Se(2), and Co(9)Se(8), respectively. In-depth studies of the Fe-Se system highlight the precise phase targeting and purification that is achievable, with PbO-type FeSe (the most metal-rich stable Fe-Se phase) forming exclusively when other Fe-Se phases, including mixtures, react with TOP. This chemistry also represents a new template-based nanoparticle "conversion chemistry" reaction, transforming hollow NiSe(2) nanospheres into hollow NiSe nanospheres with morphological retention.

  14. Protective effect of chlorophyllin and lycopene from water spinach extract on cytotoxicity and oxidative stress induced by heavy metals in human hepatoma cells.

    Science.gov (United States)

    Yang, Ui-Jeong; Park, Tae-Sik; Shim, Soon-Mi

    2013-01-01

    The purpose of this study was to examine the inhibitory effects of ethanol extract of water spinach (EEWS) containing chlorophyll and lycopene on cytotoxicity and oxidative stress in liver induced by heavy metals. The (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) MTT assay and dichlorofluorescein (DCF) assay were conducted to measure cytotoxicity and inhibition of reactive oxygen species (ROS), respectively. Cytotoxicity was prevented at a concentration of 11.7 mg/L of EEWS. Both sodium copper chlorophyllin (SCC) and lycopene in EEWS were identified by ultraperformance liquid chromatography-photodiode array-electrospray ionization-mass spectroscopy (UPLC-PDA-ESI-MS/MSn) as major components at m/z 722.64 and 535.45, respectively. The concentrations of SCC and lycopene were 0.12 and 0.04 mg from 100 g of dried powder, respectively. Approximately 99% cytotoxicity induced by Cd was inhibited by EEWS. However, the inhibitory effect attributed to generation of ROS was similar with SCC, lycopene, and EEWS. Our results indicated that EEWS was effective in reducing cytotoxicity and oxidative stress produced by heavy metals in a HepG2 cell. Data suggest that the possible mechanism underlying the preventive action of SCC might be associated with diminished absorption of metal ions by chelating and blocking metal-mediated generation of ROS, while lycopene effects may be attributed to its high number of conjugated dienes that act as most potent singlet oxygen quenchers.

  15. Preparation of magnetic metal organic frameworks adsorbent modified with mercapto groups for the extraction and analysis of lead in food samples by flame atomic absorption spectrometry.

    Science.gov (United States)

    Wang, Yang; Chen, Huanhuan; Tang, Jie; Ye, Guiqin; Ge, Huali; Hu, Xiaoya

    2015-08-15

    A novel magnetic metal organic frameworks adsorbent modified with mercapto groups was synthesized and developed for extraction and spectrophotometric determination of trace lead. The adsorbent was characterized by Fourier transforms infrared spectrometer, X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry. The results indicated the adsorbents exhibited high adsorption capacities for lead due to the chelation mechanism between metal cations and mercapto groups. Meanwhile, the lead sorption onto the adsorbents could be easily separated from aqueous solution using a magnetic separation method. Under the optimal conditions, a linear calibration curve in the range from 1 to 20 μg L(-1) was achieved with an enrichment factor of 100. The limits of detection and quantitation for lead were found to be 0.29 and 0.97 μg L(-1), respectively. The developed method was successfully applied to the determination of trace amounts of lead in food samples and certified reference material with satisfactory results.

  16. Human Health Risk Assessment Based on Toxicity Characteristic Leaching Procedure and Simple Bioaccessibility Extraction Test of Toxic Metals in Urban Street Dust of Tianjin, China

    Science.gov (United States)

    Yu, Binbin; Wang, Yu; Zhou, Qixing

    2014-01-01

    The potential ecological and human health risk related with urban street dust from urban areas of Tianjin, China was quantitatively analyzed using the method of toxicity characteristic leaching procedure (TCLP) and simple bioaccessibility extraction test (SBET). In the study, Hakason index, Nemerow index (P), the hazard index (HI) and the cancer risk index (RI) were calculated to assess the potential risk. The sequence of potential ecological risk based on Hakason index was arsenic (As) > cadmium (Cd) > lead (Pb) > copper (Cu) > chromium (Cr), in particular, As and Cd were regarded as high polluted metals. While the results of extraction of TCLP were assessed using P, the sequence was As > Pb > Cd > Cr > Cu, which mean that As and Pb should be low polluted, and Cd, Cr and Cu would barely not polluted. For human health, total carcinogenic risk for children and adults was 2.01×10−3 and 1.05×10−3, respectively. This could be considered to be intolerable in urban street dust exposure. The sequence in the hazard quotient (HQ) of each element was As > Cr > Pb > Cu > Cd. The HI value of these toxic metals in urban street dust for children and adults was 5.88×10−1 and 2.80×10−1, respectively. According to the characters of chemistry, mobility, and bioavailability of metals in urban street dust, we estimated the hazards on the environment and human health, which will help us to get more reasonable information for risk management of metals in urban environment. PMID:24651129

  17. Comparison between B CR sequential extraction and geo-accumulation method to evaluate metal mobility in sediments of Dongting Lake, Central China

    Institute of Scientific and Technical Information of China (English)

    YAO Zhigang

    2008-01-01

    The form in which a metal exists strongly influences its mobility and thus,the effects on the environment.Operational methods of speciation analysis,such as the use of sequential extraction procedures,are commonly applied.The Dongting Lake,the second largest fresh-water lake in China,contains three China wetlands of international importance,the East Dongting Lake,South Dongting Lake,and West Dongting Lake.In this work,an optimized BCR sequential extraction procedure was used to assess the environmental risk of Cd,Cr,Cu,Ni,Pb and Zn in contaminated sediment of the Dongting Lake.The procedure was evaluated by using a certified reference material,BCR701.The results of the partitioning study indicated that in the lake sediments,more easily mobilized forms(acid exchangeable) were predominant for Cd,particularly in the samples from the East Dongting Lake.In contrast,the largest amount of Pb was associated with the iron and manganese oxide fractions and Cu,Zn,Cr,and Ni analyzed were mainly distributed in residual phase at an average percentage greater than 60% of the total metals.The potential risk to the lake's water contamination was highest in the East Dongting Lake based on the calculated contamination factors.On the other hand,the total metal content was determined as well by inductively coupled plasma and mass spectrometry(ICP-MS)and assessed by using geo-accumulation index.The assessment results using geo-accumulation index were compared with the information on metal speciation.Both were correspondent with each other.

  18. Human health risk assessment based on toxicity characteristic leaching procedure and simple bioaccessibility extraction test of toxic metals in urban street dust of Tianjin, China.

    Directory of Open Access Journals (Sweden)

    Binbin Yu

    Full Text Available The potential ecological and human health risk related with urban street dust from urban areas of Tianjin, China was quantitatively analyzed using the method of toxicity characteristic leaching procedure (TCLP and simple bioaccessibility extraction test (SBET. In the study, Hakason index, Nemerow index (P, the hazard index (HI and the cancer risk index (RI were calculated to assess the potential risk. The sequence of potential ecological risk based on Hakason index was arsenic (As > cadmium (Cd > lead (Pb > copper (Cu > chromium (Cr, in particular, As and Cd were regarded as high polluted metals. While the results of extraction of TCLP were assessed using P, the sequence was As > Pb > Cd > Cr > Cu, which mean that As and Pb should be low polluted, and Cd, Cr and Cu would barely not polluted. For human health, total carcinogenic risk for children and adults was 2.01 × 10(-3 and 1.05 × 10(-3, respectively. This could be considered to be intolerable in urban street dust exposure. The sequence in the hazard quotient (HQ of each element was As > Cr > Pb > Cu > Cd. The HI value of these toxic metals in urban street dust for children and adults was 5.88 × 10(-1 and 2.80 × 10(-1, respectively. According to the characters of chemistry, mobility, and bioavailability of metals in urban street dust, we estimated the hazards on the environment and human health, which will help us to get more reasonable information for risk management of metals in urban environment.

  19. Assessment of heavy metals mobility and toxicity in contaminated sediments by sequential extraction and a battery of bioassays.

    Science.gov (United States)

    Baran, Agnieszka; Tarnawski, Marek

    2015-08-01

    The aim of this study was to assess heavy metals mobility and toxicity in sediments collected from a dam reservoir in the conditions of intensive human impact by using chemical fractionation and a battery of bioassays. In the studies, the test organisms were exposed to substances dissolved in water (Microtox, Phytotestkit) as well to substances absorbed on the surface of solid particles (Phytotoxkit, Ostracodtoxkit F). The studies showed that sediments from the Rybnik reservoir are toxic, but the tested organisms showed different sensitivity to heavy metals occurring in the bottom sediments. The sediment samples were classified as toxic and very toxic. Moreover, the studies showed a higher toxicity in solid phases and whole sediment than in pore water. The lowest sensitivity was observed in H. incongruens (solid phases) and V. fischeri (pore water, whole sediment). The studies revealed that the toxicity of the sediments is caused mainly by heavy metal forms associated with the solid phase of the sediments. The studies did not confirm the metals occurring in fraction I (exchangeable) to be bioavailable and toxic to living organisms because most correlations between the metal concentration in fraction I and the response of the organisms were negative. The highest mobility from the bottom sediments was found in zinc, average mobility--in copper, cadmium and nickel, and low mobility--in chromium and lead. Organic matter is likely to be the most important factor controlling metal distribution and mobility in the studied sediments.

  20. Effect of Crystallinity on Electrochemical Insertion/Extraction of Li in Transition Metal Oxides Part II: TiO2, V2O5 and MoOs

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Electrochemical irtsertion/extraction of Li on cathode materials of anatase type TiO2, quasilayered structure V2O5 and layered structure MoO3 was measured on samples of which structures were well characterized and showed a wide range of crystallinity. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materials on electrochemical Li insertion/extraction performance was discussed.These three transition metal oxides were classified as one group on the basis of whether the crystallirfity of these oxides affects to the performance or not; LiMn2O4 and LiCo0.5Ni0.5O2belongs to the former group and TiO2, V2O5 and MoO3 to the latter.

  1. Assessing the utility of FIB-SEM images for shale digital rock physics

    Science.gov (United States)

    Kelly, Shaina; El-Sobky, Hesham; Torres-Verdín, Carlos; Balhoff, Matthew T.

    2016-09-01

    Shales and other unconventional or low permeability (tight) reservoirs house vast quantities of hydrocarbons, often demonstrate considerable water uptake, and are potential repositories for fluid sequestration. The pore-scale topology and fluid transport mechanisms within these nanoporous sedimentary rocks remain to be fully understood. Image-informed pore-scale models are useful tools for studying porous media: a debated question in shale pore-scale petrophysics is whether there is a representative elementary volume (REV) for shale models? Furthermore, if an REV exists, how does it differ among petrophysical properties? We obtain three dimensional (3D) models of the topology of microscale shale volumes from image analysis of focused ion beam-scanning electron microscope (FIB-SEM) image stacks and investigate the utility of these models as a potential REV for shale. The scope of data used in this work includes multiple local groups of neighboring FIB-SEM images of different microscale sizes, corresponding core-scale (milli- and centimeters) laboratory data, and, for comparison, series of two-dimensional (2D) cross sections from broad ion beam SEM images (BIB-SEM), which capture a larger microscale field of view than the FIB-SEM images; this array of data is larger than the majority of investigations with FIB-SEM-derived microscale models of shale. Properties such as porosity, organic matter content, and pore connectivity are extracted from each model. Assessments of permeability with single phase, pressure-driven flow simulations are performed in the connected pore space of the models using the lattice-Boltzmann method. Calculated petrophysical properties are compared to those of neighboring FIB-SEM images and to core-scale measurements of the sample associated with the FIB-SEM sites. Results indicate that FIB-SEM images below ∼5000 μm3 volume (the largest volume analyzed) are not a suitable REV for shale permeability and pore-scale networks; i.e. field of view

  2. Magnetic metal-organic framework MIL-100(Fe) microspheres for the magnetic solid-phase extraction of trace polycyclic aromatic hydrocarbons from water samples.

    Science.gov (United States)

    Du, Fuyou; Qin, Qun; Deng, Jianchao; Ruan, Guihua; Yang, Xianqing; Li, Laihao; Li, Jianping

    2016-06-01

    In this work, a magnetic metal-organic framework designated as MIL-100(Fe) was prepared and applied as a magnetic solid-phase extraction sorbent for the determination of trace polycyclic aromatic hydrocarbons in environmental water samples by coupling with high-performance liquid chromatography and fluorescence detection. The magnetic microspheres exhibited large surface areas and high extraction ability, making them excellent candidates as sorbents for enrichment of trace polycyclic aromatic hydrocarbons. Under the optimized experimental conditions, good sensitivity levels were achieved with low detection limits ranging from 32 to 2110 pg/mL and good linearities with correlation coefficients higher than 0.9990 for the investigated 13 polycyclic aromatic hydrocarbons. The proposed method has been validated in the analysis of real water samples with mean recoveries in the range of 81.4-126.9% at four spiked levels and the relative standard deviations in the range of 1.3-17.0%. The magnetic MIL-100(Fe) microspheres were stable enough for 150 extractions without a significant loss of extraction performance.

  3. Sequential Extraction Results and Mineralogy of Mine Waste and Stream Sediments Associated With Metal Mines in Vermont, Maine, and New Zealand

    Science.gov (United States)

    Piatak, N.M.; Seal, R.R.; Sanzolone, R.F.; Lamothe, P.J.; Brown, Z.A.; Adams, M.

    2007-01-01

    We report results from sequential extraction experiments and the quantitative mineralogy for samples of stream sediments and mine wastes collected from metal mines. Samples were from the Elizabeth, Ely Copper, and Pike Hill Copper mines in Vermont, the Callahan Mine in Maine, and the Martha Mine in New Zealand. The extraction technique targeted the following operationally defined fractions and solid-phase forms: (1) soluble, adsorbed, and exchangeable fractions; (2) carbonates; (3) organic material; (4) amorphous iron- and aluminum-hydroxides and crystalline manganese-oxides; (5) crystalline iron-oxides; (6) sulfides and selenides; and (7) residual material. For most elements, the sum of an element from all extractions steps correlated well with the original unleached concentration. Also, the quantitative mineralogy of the original material compared to that of the residues from two extraction steps gave insight into the effectiveness of reagents at dissolving targeted phases. The data are presented here with minimal interpretation or discussion and further analyses and interpretation will be presented elsewhere.

  4. Dentin desensitizing agents: SEM and X-ray microanalysis assessment.

    Science.gov (United States)

    Jain, P; Vargas, M A; Denehy, G E; Boyer, D B

    1997-02-01

    To evaluate the effect of four proprietary dentin desensitizing agents on dentin tubular occlusion, chemical composition changes on the dentin surface, and the effect of saliva and toothbrushing on these agents. Fifty dentin discs, obtained from 50 freshly extracted human premolar and molar teeth were used in this study. These were divided into five groups of 10 discs each. Five discs from each group were treated with the desensitizing agents, viewed under the SEM and subjected to energy dispersive X-ray analysis. The other five discs were treated with the desensitizing agents, immersed in artificial saliva, subjected to simulated toothbrushing equivalent to 3 weeks of normal brushing and viewed under the SEM. The agents studied were Sensodyne Dentin Desensitizer, Therma-Trol Desensitizer Gel, Gluma Desensitizer and All-Bond DS. The Kruskal-Wallis test followed by the Wilcoxon signed-rank test showed that Sensodyne Dentin Desensitizer exhibited the greatest amount of tubular occlusion among the unbrushed samples, followed by Therma-Trol Desensitizer Gel, Gluma Desensitizer and All-Bond DS (P Sensodyne Dentin Desensitizer treated samples.

  5. High resolution SEM imaging of gold nanoparticles in cells and tissues.

    Science.gov (United States)

    Goldstein, A; Soroka, Y; Frušić-Zlotkin, M; Popov, I; Kohen, R

    2014-12-01

    The growing demand of gold nanoparticles in medical applications increases the need for simple and efficient characterization methods of the interaction between the nanoparticles and biological systems. Due to its nanometre resolution, modern scanning electron microscopy (SEM) offers straightforward visualization of metallic nanoparticles down to a few nanometre size, almost without any special preparation step. However, visualization of biological materials in SEM requires complicated preparation procedure, which is typically finished by metal coating needed to decrease charging artefacts and quick radiation damage of biomaterials in the course of SEM imaging. The finest conductive metal coating available is usually composed of a few nanometre size clusters, which are almost identical to the metal nanoparticles employed in medical applications. Therefore, SEM monitoring of metal nanoparticles within cells and tissues is incompatible with the conventional preparation methods. In this work, we show that charging artefacts related to non-conductive biological specimen can be successfully eliminated by placing the uncoated biological sample on a conductive substrate. By growing the cells on glass pre-coated with a chromium layer, we were able to observe the uptake of 10 nm gold nanoparticles inside uncoated and unstained macrophages and keratinocytes cells. Imaging in back scattered electrons allowed observation of gold nanoparticles located inside the cells, while imaging in secondary electron gave information on gold nanoparticles located on the surface of the cells. By mounting a skin cross-section on an improved conductive holder, consisting of a silicon substrate coated with copper, we were able to observe penetration of gold nanoparticles of only 5 nm size through the skin barrier in an uncoated skin tissue. The described method offers a convenient modification in preparation procedure for biological samples to be analyzed in SEM. The method provides high

  6. Synthesis and application of Fe3O4@SiO2@TiO2 for photocatalytic decomposition of organic matrix simultaneously with magnetic solid phase extraction of heavy metals prior to ICP-MS analysis.

    Science.gov (United States)

    Habila, Mohamed A; ALOthman, Zeid A; El-Toni, Ahmed Mohamed; Labis, Joselito Puzon; Soylak, Mustafa

    2016-07-01

    Interference of organic compounds in the matrix of heavy metal solution could suppress their pre-concentration and detection processes. Therefore, this work aimed to develop simple and facile methods for separation of heavy metals before ICP-MS analysis. Fe3O4@SiO2@TiO2 core-double shell magnetic adsorbent was prepared and characterized by TEM, SEM, FTIR, XRD and surface area, and tested for Magnetic Solid Phase Extraction (MSPE) of Cu(II), Zn(II), Cd(II) and Pb(II). TEM micrograph of Fe3O4@SiO2@TiO2 reveals the uniform coating of TiO2 layer of about 20nm onto the Fe3O4@SiO2 nanoparticles and indicates that all nanoparticles are monodispersed and uniform. The saturation magnetization from the room-temperature hysteresis loops of Fe3O4 and Fe3O4@SiO2@TiO2 was found to be 72 and 40emug(-1), respectively, suggesting good separability of the nanoparticles. The Fe3O4@SiO2@TiO2 showed maximum adsorption capacity of 125, 137, 148 and 160mgg(-1) for Cu(II), Zn(II), Cd(II) and Pb(II) respectively, and the process was found to fit with the second order kinetic model and Langmuir isotherm. Fe3O4@SiO2@TiO2 showed efficient photocatalytic decomposition for tartrazine and sunset yellow (consider as Interfering organic compounds) in aqueous solution under the irradiation of UV light. The maximum recovery% was achieved at pH 5, by elution with 10mL of 2M nitric acid solution. The LODs were found to be 0.066, 0.049, 0.041 and 0.082µgL(-1) for Cu(II), Zn(II), Cd(II) and Pb(II), respectively while the LOQs were found to be 0.20, 0.15, 0.12 and 0.25µgL(-1) for Cu(II), Zn(II), Cd(II) and Pb(II), respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Semântica expressivista = Expressivist semantics

    Directory of Open Access Journals (Sweden)

    Mendonça, Wilson John Pessoa

    2016-01-01

    Full Text Available O programa semântico do expressivismo surgiu como uma tentativa de fundamentar a visão não-cognitivista do discurso ético, mas logo foi generalizado de forma a cobrir a linguagem normativa em geral. Ele promete desenvolver uma alternativa global à abordagem clássica da semântica das condições de verdade: uma teoria não-factualista, baseada na pragmática, do significado linguístico. Os expressivistas veem o conteúdo das sentenças normativas como determinado por seu uso primário, que é não-descritivo. As versões tradicionais da semântica expressivista procedem associando sistematicamente às sentenças normativas as atitudes mentais que elas convencionalmente expressam. Elas assumem que, se as sentenças simples expressam atitudes, a aplicação a essas sentenças dos conectivos da lógica proposicional ou da ligação de variáveis resulta em sentenças complexas que também expressam atitudes. O núcleo do presente trabalho avalia algumas tentativas influentes de desenvolvimento do programa expressivista, focando em um problema discutido com veemência na literatura: o “problema da negação para o expressivismo”. Algumas abordagens propostas nos últimos anos, baseadas na rejeição da assunção central do expressivismo tradicional, são consideradas em detalhes. Embora uma avaliação definitiva dessas abordagens inovadoras como explicações satisfatórias do funcionamento da linguagem normativa não possa ainda ser alcançada, o trabalho afirma que há razões para otimismo

  8. Estudo da cicatrização de suturas na bexiga urinária de ratos com e sem a utilização de extrato bruto de Jatropha gossypiifolia L. intraperitoneal Healing process in bladder suture of rats with and without the administration of intraperitoneal Jatropha gossypiifolia L. gross extract

    Directory of Open Access Journals (Sweden)

    José Maria Ayres Maia

    2006-01-01

    Full Text Available INTRODUÇÃO: A sutura dos tecidos e sua cicatrização é um dos fundamentos básicos da cirurgia e a procura de substâncias que melhorem este processo é desafio constante. O uso de substâncias retiradas de plantas tem sido testado há muitos anos, contudo sem ainda terem comprovação científica consolidada. OBJETIVO: Comparar as alterações macroscópicas e histológicas proporcionadas pelo uso do extrato bruto da Jatropha gossypiifolia L. intraperitonial, na cicatrização de suturas realizadas na bexiga urinária de ratos. MÉTODOS: Quarenta ratos da linhagem wistar, adultos, machos foram distribuídos em dois grupos, experimento e controle. Incisão longitudinal de 1cm na parede ventral da bexiga e síntese em plano único com pontos separados de poliglactina 910 5-0 (ethicon foi realizada nos dois grupos. No controle, instilou-se na cavidade peritoneal água destilada na proporção de 1ml/kg de peso, enquanto no grupo Jatropha utilizou-se o extrato bruto de Jatropha gossypiifolia L. na proporção de 1ml/kg, que representava 200mg/kg de peso do fitoterápico. Cada grupo foi subdividido em dois subgrupos de 10 animais, sendo estes submetidos à eutanásia no 3º e 7º dia pós-operatório. Foi feita análise macroscópica e histológica comparativa entre os subgrupos. RESULTADOS: No 3º dia foi observada diferença estatisticamente significante nas variáveis inflamação aguda, neoformação vascular e colagenização, sendo a primeira, maior no grupo controle e as duas últimas no grupo Jatropha; no 7º dia as variáveis inflamação aguda e proliferação fibroblástica apresentaram-se mais intensas, com significado estatístico, no grupo controle. CONCLUSÃO: Não se observou efeito favorecedor cicatrizante do extrato bruto da Jatropha gossypiifolia L., intraperitonealmente aplicado, na bexiga urinária de ratos.INTRODUCTION: The suture of tissues and their healing process is one of the basic fundamentals of surgery, and the

  9. Principios sobre semáforos

    OpenAIRE

    Valencia Alaix, Víctor Gabriel

    2000-01-01

    Debido a la ausencia de una publicación que reuniese los aspectos más relevantes sobre semáforos y en el marco académico sobre ingeniería de tránsito de los cursos de pregrado y posgrado en Vías y Transporte de la Universidad Nacional de Colombia - Sede Medellín, se ha preparado este documento como guía introductoria a dicho tema. En su preparación se han recogido los tópicos principales de varias publicaciones internacionales y nacionales, además, su desarrollo ha considerado la experi...

  10. O ciberativismo sem bússola

    Directory of Open Access Journals (Sweden)

    Francisco Rüdiger

    2014-07-01

    Full Text Available Questiona-se no texto se uma abordagem que, no essencial, relata a trajetória do chamado ciberativismo de acordo com seus próprios termos se justifica academicamente ou, em vez disso, se mantém prisioneira de uma mitologia que o fenômeno, em si mesmo, já construiu e, por isso, autoriza seus sujeitos a dispensarem sem prejuízo eventual contribuição de origem universitária.

  11. Metal-organic frameworks@graphene hybrid aerogels for solid-phase extraction of non-steroidal anti-inflammatory drugs and selective enrichment of proteins.

    Science.gov (United States)

    Zhang, Xiaoqiong; Liang, Qionglin; Han, Qiang; Wan, Wei; Ding, Mingyu

    2016-06-20

    Graphene aerogel (GA)-supported metal-organic framework (MOF) particles with a three-dimensional (3D) architecture were fabricated for the first time via a facile template-free "sol-cryo" method. The prepared MOFs@graphene hybrid aerogels exhibit a 3D interconnected macroporous framework of graphene sheets with uniform dispersion of MOF particles. We also report the first attempt at using the hybrid aerogels as adsorbents for the solid-phase extraction (SPE) of non-steroidal anti-inflammatory drugs (NSAIDs) and the selective enrichment of proteins. The macroporous skeletons of GA provide both low backpressure and rapid mass transfer in SPE application, thus overcoming the obstacle of high backpressure caused by directly packing submicron or micron sized MOF particles into SPE cartridges. Excellent performances including satisfactory recoveries, high sensitivity and good reproducibility were achieved in the extraction of five NSAIDs. The hybrid aerogels also showed an interesting ability for selective enrichment of ribonuclease A (RNase A) and simultaneous exclusion of cytochrome C (Cyt C) and lysozyme (Lyz), which could be attributed to the electrostatic interactions between proteins and the positively charged coordinatively unsaturated metal sites (CUS) in MIL-101. We believe that this work will promote the application of MOFs in adsorption and separation, and our synthetic strategy could be further extended to develop other graphene-based hybrid aerogels.

  12. Trace Metals in Saharan Dust: The Use of in Vitro Bioaccessibility Extractions To Assess Potential Health Risks in a Dustier World: Chapter 3

    Science.gov (United States)

    Morman, Suzette A.; Garrison, Virginia H.; Plumlee, Geoffrey S.

    2013-01-01

    Exposure to fine particulate matter (PM) is acknowledged as a risk factor for human morbidity and mortality. Epidemiology and toxicology studies have focused on anthropogenic sources of PM and few consider contributions produced by natural processes (geogenic), or PM produced from natural sources as a result of human activities (geoanthropogenic PM). The focus of this study was to elucidate relationships between human/ecosystem health and dusts produced by a system transitioning from a dominantly natural to a geoanthropogenic PM source. As part of a larger study investigating the relationship between atmospheric transportation of African dust, human health, and coral reef declines, we examined dust samples sourced in Mali, Africa, collected using high-volume samplers from three sites (Mali, Tobago and U.S. Virgin Islands). Inhalation and ingestion exposure pathways were explored by filter extractions using simulated lung and gastric fluids. Bioaccessibility varied by metal and extraction fluid. Although too few samples were analyzed for robust statistics, concentrations for several metals decreased slightly while bioaccessibility increased at downwind sites.

  13. Polydimethylsiloxane/metal-organic frameworks coated stir bar sorptive extraction coupled to high performance liquid chromatography-ultraviolet detector for the determination of estrogens in environmental water samples.

    Science.gov (United States)

    Hu, Cong; He, Man; Chen, Beibei; Zhong, Cheng; Hu, Bin

    2013-10-04

    In this work, three kinds of metal-organic frameworks (MOFs), MOF-5, MOF-199 and IRMOF-3, were introduced in stir bar sorptive extraction (SBSE) and novel polydimethylsiloxane (PDMS)/MOFs (including PDMS/MOF-5, PDMS/MOF-199 and PDMS/IRMOF-3) coated stir bars were prepared by sol-gel technique. These PDMS/MOFs coatings were characterized and critically compared for the extraction of seven target estrogens (17-β-estradiol, dienestrol, diethylstilbestrol, estrone, 4-t-octylphenol, bisphenol-A and 17α-ethynylestradiol) by SBSE, and the results showed that PDMS/IRMOF-3 exhibited highest extraction efficiency. Based on the above facts, a novel method of PDMS/IRMOF-3 coating SBSE-high performance liquid chromatography ultraviolet (HPLC-UV) detection was developed for the determination of seven target estrogens in environmental waters. Several parameters affecting extraction of seven target estrogens by SBSE (PDMS/IRMOF-3) including extraction time, stirring rate, pH, ionic strength, desorption solvent and desorption time were investigated. Under the optimal experimental conditions, the limits of detection (LODs, S/N=3) were found to be in the range of 0.15-0.35 μg/L. The linear range was 2-2,500 μg/L for 17α-ethynylestradiol and 1-2,500 μg/L for other estrogens. The relative standard deviations (RSDs) were in the range of 3.7-9.9% (n=8, c=20 μg/L) and the enrichment factors were from 30.3 to 55.6-fold (theoretical enrichment factor was 100-fold). The proposed method was successfully applied to the analysis of estrogens in environmental water samples, and quantitative recoveries were obtained for the spiking experiments.

  14. Estudo cefalométrico das alterações das alturas faciais anterior e posterior em pacientes leucodermas, com má oclusão de classe II, 1ª divisão de Angle, tratados com e sem extração de quatro primeiros pré-molares The influence of orthodontic extraction and nonextraction treatment on anterior and posterior facial heights

    Directory of Open Access Journals (Sweden)

    Daniele Teixeira Machado

    2005-12-01

    Full Text Available OBJETIVO: este estudo cefalométrico longitudinal visou avaliar, comparativamente, as alterações das alturas faciais, provenientes do tratamento da má oclusão de Classe II, 1ª divisão de Angle, pela Técnica de "Edgewise", associado à ancoragem extrabucal cervical, com e sem extração de quatro primeiros pré-molares. METODOLOGIA: a amostra constituiu-se de 116 telerradiografias em norma lateral obtidas de 56 jovens, de ambos os gêneros. Destes jovens, 22 foram tratados ortodonticamente com extração de quatro primeiros pré-molares e apresentavam idade média inicial de 12,30 e final de 14,87 anos, constituindo o grupo I. Outros 22 foram tratados ortodonticamente sem extração e apresentavam idade média inicial de 12,53 e idade média final de 14,73 anos, formando o grupo II. Os demais 14 jovens com idade média inicial de 11,50 e final de 13,63 anos, não foram submetidos a nenhuma intervenção ortodôntica, formando assim o grupo controle (grupo III. RESULTADOS E CONCLUSÕES: os resultados demonstraram que não houve influência significante da terapia ortodôntica sobre as alterações das alturas faciais. Os primeiros molares superiores e inferiores desenvolveram-se no sentido vertical nos três grupos. As alterações horizontais dentoalveolares evidenciaram uma mesialização dos primeiros molares superiores e inferiores em todos os grupos, contudo o maior deslocamento para mesial ocorreu no grupo tratado com extração de quatro primeiros pré-molares e no grupo controle. Este fato prova que, no grupo tratado sem extração, a Classe II foi corrigida não pela distalização dos primeiros molares superiores, mas pela restrição da mesialização dos mesmos.AIM: the cephalometric changes of anterior and posterior facial heights, in the Class II, Division 1 treatment, were compared among three different groups of patients: 4-premolar extraction, non-extraction and control. METHODS: each test sample consisted of 22 patients

  15. Towards a method of rapid extraction of strontium-90 from urine: urine pretreatment and alkali metal removal

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Dietz, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Kaminski, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Mertz, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Shkrob, I. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-03-01

    A technical program to support the Centers of Disease Control and Prevention is being developed to provide an analytical method for rapid extraction of Sr-90 from urine, with the intent of assessing the general population’s exposure during an emergency response to a radiological terrorist event. Results are presented on the progress in urine sample preparation and chemical separation steps that provide an accurate and quantitative detection of Sr-90 based upon an automated column separation sequence and a liquid scintillation assay. Batch extractions were used to evaluate the urine pretreatment and the column separation efficiency and loading capacity based upon commercial, extractant-loaded resins. An efficient pretreatment process for decolorizing and removing organics from urine without measurable loss of radiostrontium from the sample was demonstrated. In addition, the Diphonix® resin shows promise for the removal of high concentrations of common strontium interferents in urine as a first separation step for Sr-90 analysis.

  16. Sequential extractions on mine tailings samples after and before bioassays: implications on the speciation of metals during microbial re-colonization

    Science.gov (United States)

    García-Meza, J. V.; Carrillo-Chávez, A.; Morton-Bermea, O.

    2006-01-01

    Mine tailings may be remediated using metal tolerant microorganisms as they may solve the limiting conditions for healthy development of plants (i.e., low organic mater content and poor physical conditions). The aim of this study was to investigate the consequences of microbial colonization on the chemical speciation of trace metals. Surface samples from the Valenciana mine tailings (Guanajuato, Mexico) were used for long-term bioassays (BA), which consisted in the promotion of microorganisms, development on tailings material under stable laboratory conditions (humidity, temperature, and light exposure). A five-step sequential extraction method (exchangeable, carbonate/specifically adsorbed, Fe-Mn oxides, organic matter (OM)/sulfide, and residual fractions) was performed before and after BA. Extraction solutions and leachates were analyzed by inductively coupled plasma-mass spectrometry. OM content, cationic exchange capacity, and pH values were also assessed before and after BA. The results indicate that trace elements are generally present in nonresidual fractions, mainly in the Fe-Mn oxides fraction. The concentration of total Zn, As, Se, Pb, and exchangeable Cu and Pb is above the recommendable limits for soils. Despite the high bioavailability of the former elements, biofilms successfully colonized the tailing samples during the BA. Cyanobacteria and green algae, heterotrophic fungi, aerobic bacteria, and anaerobic bacteria composed the developed biofilms. Chemical controls of trace elements could be attributed to absorption onto inorganic complexes (carbonates, metal oxides), while biofilm occurrence seems to enhance complexation and immobilization of Cr, Ni, Cu, Zn, As, and Pb. The biofilm developed does not increase the bioavailable forms and the leaching of the trace elements, but significantly improves the OM contents (natural fertilization). The results suggest that biofilms are useful during the first steps of the mine tailings remediation.

  17. Adsorption of acid-extractable organics from oil sands process-affected water onto biomass-based biochar: Metal content matters.

    Science.gov (United States)

    Bhuiyan, Tazul I; Tak, Jin K; Sessarego, Sebastian; Harfield, Don; Hill, Josephine M

    2017-02-01

    The impact of biochar properties on acid-extractable organics (AEO) adsorption from oil sands process-affected water (OSPW) was studied. Biochar from wheat straw with the highest ash content (14%) had the highest adsorption capacity (0.59 mg/g) followed by biochar from pulp mill sludge, switchgrass, mountain pine, hemp shives, and aspen wood. The adsorption capacity had no obvious trend with surface area, total pore volume, bulk polarity and aromaticity. The large impact of metal content was consistent with the carboxylates (i.e., naphthenate species) in the OSPW binding to the metals (mainly Al and Fe) on the carbon substrate. Although the capacity of biochar is still approximately two orders of magnitude lower than that of a commercial activated carbon, confirming the property (i.e., metal content) that most influenced AEO adsorption, may allow biochar to become competitive with activated carbon after normalizing for cost, especially if this cost includes environmental impacts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Extraction of metal ions using chemically modified silica gel covalently bonded with 4,4'-diaminodiphenylether and 4,4'-diaminodiphenylsulfone-salicylaldehyde Schiff bases.

    Science.gov (United States)

    Dey, R K; Jha, Usha; Singh, A C; Samal, S; Ray, Alok R

    2006-08-01

    Two new chelating materials (Si-DDE-o-HB, and Si-DDS-o-HB) were synthesized by modifying the activated silica gel phase with Schiff bases of 4,4'-diaminodiphenylether (DDE)/4,4'-diaminodiphenylsulfone (DDS) and o-hydroxybenzaldehyde (o-HB). The synthesized materials were characterized by FTIR and BET surface area measurement techniques. The extraction of metal ions such as Zn2+, Mn2+ and Cr3+ by the chelating material Si-DDE-o-HB was found to be higher than that by Si-DDS-o-HB. The order of metal sorption was found to be Zn2+ > Mn2+ > Cr3+. The correlation coefficients for Freundlich and Langmuir adsorption isotherms were compared for the sorption of Zn2+ onto the chelating material. The loading and elution of the metal ion solution was examined at optimum pH 7.5 and 0.5 cm3 min-1 flow rate of the solution using a column technique. The preconcentration factor for the elution of Zn2+ using dilute HNO3 was found to be 66.2 with a breakthrough volume of 15 cm3. The data obtained for the preconcentration of Zn2+ by the column technique suggested that the material Si-DDE-o-HB can find industrial applications.

  19. Separation of rhenium from molybdenum, tungsten, vanadium, platinum metals and other elements by reduction and solvent extraction.

    Science.gov (United States)

    Yatirajam, V; Kakkar, L R

    1970-08-01

    Reduction in 1 M H(2)SO(4) with liquid zinc amalgam and extraction with isopentanol from 3M H(2)SO(4), separates rhenium from almost all the interfering elements of importance in rhenium determination. The small amounts of Mo, U, Fe and Ru still accompanying rhenium are removed by the thiocyanate-pentyl acetate or the oxine-chloroform extraction. The method is simple, rapid and of very wide applicability. It is particularly useful in the determination of rhenium in various alloys and tungsten-containing samples.

  20. Fe^3+浸提剩余污泥中重金属试验%Fe^3+ Extraction of Heavy Metals in the Remaining Sludge

    Institute of Scientific and Technical Information of China (English)

    杨苏谦; 陈斌; 王琴; 郑柏锐; 冒陈凯; 徐思民

    2012-01-01

    在室温下,污泥固液比例1∶20的条件下,以氯化铁为萃取剂对污泥进行重金属浸提的研究试验。分别进行了不同浓度的氯化铁溶液、pH值、振速及浸提时间对污泥浸提的效果影响试验。结果表明:当FeCl3溶液浓度小于48 mmol/L时,Zn和Cu的去除率随着浓度的增加而升高,当FeCl3溶液浓度大于48 mmol/L时,浓度增大对去除率的贡献降低;在相同的pH值下,氯化铁溶液比盐酸溶液更能有效的浸出污泥中的重金属;浸提的较佳振速为150 r/min,浸提的最佳时间为24 h。%At room temperature,under the conditions of sludge and solid-liquid radio of 1:20,with ferric chloride as an extraction agent of heavy metals extracted from the sludge by the line test were carried out with different concentrations of ferric chloride solution,the pH value,vibration velocity and extraction time on the extraction test.The results showed that when FeCl3 solution concentration was less than 48 mmol/L,Zn and Cu removal rate increased with increasing concentrations of FeCl3 solution concentration greater than 48 mmol/L,the increased concentration reduced the removal rate of contribution.Under the same pH value,heavy metals in the sludge of ferric chloride solution were more effective than hydrochloric acid leaching,better vibration velocity was 150 r/min and the best time of extraction was 24 h.

  1. Scanning Electron Microscopy (SEM) Procedure for HE Powders on a Zeiss Sigma HD VP SEM

    Energy Technology Data Exchange (ETDEWEB)

    Zaka, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-11-15

    This method describes the characterization of inert and HE materials by the Zeiss Sigma HD VP field emission Scanning Electron Microscope (SEM). The SEM uses an accelerated electron beam to generate high-magnification images of explosives and other materials. It is fitted with five detectors (SE, Inlens, STEM, VPSE, HDBSD) to enable imaging of the sample via different secondary electron signatures, angles, and energies. In addition to imaging through electron detection, the microscope is also fitted with two Oxford Instrument Energy Dispersive Spectrometer (EDS) 80 mm detectors to generate elemental constituent spectra and two-dimensional maps of the material being scanned.

  2. Magnetic metal-organic framework-titanium dioxide nanocomposite as adsorbent in the magnetic solid-phase extraction of fungicides from environmental water samples.

    Science.gov (United States)

    Su, Hao; Lin, Yunliang; Wang, Zhenhua; Wong, Y-L Elaine; Chen, Xiangfeng; Chan, T-W Dominic

    2016-09-30

    In this work, a core-shell Fe3O4@SiO2@MOF/TiO2 nanocomposite was synthesized and used to as adsorbent for magnetic solid-phase extraction (MSPE) of triazole fungicides from environmental water samples. Five triazole fungicides, namely, triadimenol, hexaconazole, diniconazole, myclobutanil, and tebuconazole, were selected as target analytes for MSPE. These analytes were quantitatively adsorbed on microspheres, and the sorbents were separated from the solution by using a magnet. The analytes were desorbed by methanol and determined through liquid-chromatography coupled with tandem mass spectrometry. The extraction parameters affecting the extraction efficiency were optimized through response surface methodology. The limits of detection and limits of quantification for the selected fungicides were 0.19-1.20ngL(-1) and 0.61-3.62ngL(-1), respectively. The proposed method was applied to determine the concentration of fungicides in actual environmental water samples. The accuracy of the proposed method was evaluated by measuring the recovery of the spiked samples. The satisfying recoveries of the four water samples ranged from 90.2% to 104.2%. Therefore, the magnetic metal-organic framework/TiO2 nanocomposite based MSPE is a potential approach to analyze fungicides in actual water samples.

  3. Magnetic metal-organic nanotubes: An adsorbent for magnetic solid-phase extraction of polychlorinated biphenyls from environmental and biological samples.

    Science.gov (United States)

    Li, Qiu-Lin; Wang, Lei-Lei; Wang, Xia; Wang, Ming-Lin; Zhao, Ru-Song

    2016-06-03

    A new type of three-dimensional, echinus-like magnetic Fe3O4 @ cobalt(Ⅱ)-based metal-organic nanotube (Fe3O4 @ Co-MONT) yolk-shell microspheres, have been designed and synthesized for the first time. Fe3O4 @ Co-MONTs yolk-shell microspheres were characterized by scanning electron micrographs, transmission electron microscopy, Fourier transform infrared spectra, X-ray diffraction, and vibrating sample magnetometry. The feasibility of the new material for use as an absorbent was investigated for magnetic solid phase-extraction (MSPE) of polychlorinated biphenyls (PCBs) from environmental water samples and biological samples. The Plackett-Burman design and Box-Behnken design were used to determine and optimize the extraction parameters influencing the extraction efficiency through response surface methodology. Under the optimized conditions, the developed method showed good linearity within the range of 5-1000ngL(-1), low limits of detection (0.31-0.49ngL(-1)), and good reproducibility (RSD<10%). The proposed method was successfully applied for the analysis of PCBs in real environmental water samples. These results demonstrated that Fe3O4 @ Co-MONTs is a promising adsorbent material for the MSPE of PCBs at trace levels from environmental water samples and biological samples.

  4. Organically modified silica with pyrazole-3-carbaldehyde as a new sorbent for solid-liquid extraction of heavy metals

    National Research Council Canada - National Science Library

    Radi, Smaail; Tighadouini, Said; Bacquet, Maryse; Degoutin, Stéphanie; Cazier, Francine; Zaghrioui, Mustapha; Mabkhot, Yahia N

    ...). The new prepared material was used as an adsorbent for the solid-phase extraction (SPE) of Pb(II), Cd(II), Cu(II) and Zn(II) from aqueous solutions using a batch method, prior to their determination by flame atomic adsorption spectrometry...

  5. In-situ SEM electrochemistry and radiolysis

    DEFF Research Database (Denmark)

    Møller-Nilsen, Rolf Erling Robberstad; Norby, Poul

    Electron microscopy is a ubiquitous technique to see effects which are too small to see with traditional optical microscopes. Recently it has become possible to also image liquid samples by encapsulating them from the vacuum of the microscope and a natural evolution from that has been to include...... microelectrodes on the windows to enable studies of electrohcemical processes. In this way it is possible to perform in-situ electrochemical experiments such as electroplating and charge and discharge analysis of battery electrodes. In a typical liquid cell, electrons are accelerated to sufficiently high energies...... to traverse a thin window made by a silicon nitride membrane, and interact with the sample immersed in liquid. In transmission electron microscopy (TEM) the majority of the electrons continue through the sample to form an image. In scanning electron microscopy (SEM) a fraction of the electrons...

  6. SEMS: System for Environmental Monitoring and Sustainability

    Science.gov (United States)

    Arvidson, Raymond E.

    1998-01-01

    The goal of this project was to establish a computational and data management system, SEMS, building on our existing system and MTPE-related research. We proposed that the new system would help support Washington University's efforts in environmental sustainability through use in: (a) Problem-based environmental curriculum for freshmen and sophomores funded by the Hewlett Foundation that integrates scientific, cultural, and policy perspectives to understand the dynamics of wetland degradation, deforestation, and desertification and that will develop policies for sustainable environments and economies; (b) Higher-level undergraduate and graduate courses focused on monitoring the environment and developing policies that will lead to sustainable environmental and economic conditions; and (c) Interdisciplinary research focused on the dynamics of the Missouri River system and development of policies that lead to sustainable environmental and economic floodplain conditions.

  7. Chemical Engineering Division Fuel Cycle Programs. Quarterly progress report, April-June 1978. [Advanced solvent extraction; accidents; pyrochemical; radwaste in metal matrix; waste migration

    Energy Technology Data Exchange (ETDEWEB)

    Steindler, M. J.; Ader, M.; Barletta, R. E.

    1979-12-01

    Fuel cycle studies reported include development of centrifugal contactors for Purex processes. Tricaprylmethyl-ammonium nitrate and di-n-amyl-n-amylphosphonate are being evaluated as Thorex extractants. Dispersion of uranium and plutonium by fires, and mechanisms for subdividing and dispersing liquids and solids were reviewed. In the pyrochemical and dry processing program, a facility for testing containment materials is under construction; a flowsheet for carbide fuel processing has been designed and studies of carbide reactions in bismuth are underway; salt transport processes are being studied; process-size refractory metal vessels are being fabricated; the feasibility of AIROX reprocessing is being determined; the solubility of UO/sub 2/, UO/sub 2/ + fission products, and PuO/sub 2/ in molten alkali metal nitrates, has been investigated; a flowsheet was developed for reprocessing actinide oxides in molten salts; preparation of Th-U carbide from the oxide is being studied; new flowsheets based on the Dow Aluminum Pyrometallurgical process for reprocessing of spent uranium metal fuel have been prepared; the chloride volitility processing of thorium-based fuels is being studied; the reprocessing of (Th,U)O/sub 2/ solid solution in KCl-LiCl-ThCl/sub 4/-Th is being studied; and a flowsheet for processing spent nuclear fuel in molten tin has been constructed. Leach rates of simulated encapsulated waste forms in a metal matrix were studied. Nine criteria for handling waste cladding hulls were established. Strontium and tin migration in glauconite columns was measured. Radioactive Sr in a stream of water moved through oolitic limestone as rapidly as water, but in a stream of water equilibrated with the limestone, Sr moved through the limestone one-tenth as fast. Migration of trace quantities of Cs and I through kaolinite was studied. 88 figures, 53 tables.

  8. A dipole-assisted solid-phase extraction microchip combined with inductively coupled plasma-mass spectrometry for online determination of trace heavy metals in natural water.

    Science.gov (United States)

    Shih, Tsung-Ting; Hsu, I-Hsiang; Chen, Shun-Niang; Chen, Ping-Hung; Deng, Ming-Jay; Chen, Yu; Lin, Yang-Wei; Sun, Yuh-Chang

    2015-01-21

    We employed a polymeric material, poly(methyl methacrylate) (PMMA), for fabricating a microdevice and then implanted the chlorine (Cl)-containing solid-phase extraction (SPE) functionality into the PMMA chip to develop an innovative on-chip dipole-assisted SPE technique. Instead of the ion-ion interactions utilized in on-chip SPE techniques, the dipole-ion interactions between the highly electronegative C-Cl moieties in the channel interior and the positively charged metal ions were employed to facilitate the on-chip SPE procedures. Furthermore, to avoid labor-intensive manual manipulation, a programmable valve manifold was designed as an interface combining the dipole-assisted SPE microchip and inductively coupled plasma-mass spectrometry (ICP-MS) to achieve the fully automated operation. Under the optimized operation conditions for the established system, the detection limits for each analyte ion were obtained based on three times the standard deviation of seven measurements of the blank eluent solution. The limits ranged from 3.48 to 20.68 ng L(-1), suggesting that this technique appears uniquely suited for determining the levels of heavy metal ions in natural water. Indeed, a series of validation procedures demonstrated that the developed method could be satisfactorily applied to the determination of trace heavy metals in natural water. Remarkably, the developed device was durable enough to be reused more than 160 times without any loss in its analytical performance. To the best of our knowledge, this is the first study reporting on the combination of a dipole-assisted SPE microchip and elemental analysis instrument for the online determination of trace heavy metal ions.

  9. Silica chemically bonded N-propyl kriptofix 21 and 22 with immobilized palladium nanoparticles for solid phase extraction and preconcentration of some metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Ghaedi, Mehrorang, E-mail: m_ghaedi@mail.yu.ac.ir [Chemistry Department, Yasouj University, Yasouj, 75914-353 (Iran, Islamic Republic of); Niknam, Khodabakhsh, E-mail: niknam@pgu.ac.ir [Chemistry Department, Faculty of Sciences, Persian Gulf University, Bushehr, 75169 (Iran, Islamic Republic of); Zamani, Saeed; Abasi Larki, Habib [Chemistry Department, Islamic Azad University, Omidiyeh Branch, Omidiyeh (Iran, Islamic Republic of); Roosta, Mostafa [Chemistry Department, Yasouj University, Yasouj, 75914-353 (Iran, Islamic Republic of); Soylak, Mustafa [Chemistry Department, University of Erciyes, 38039 Kayseri (Turkey)

    2013-08-01

    Silica gel chemically bonded N-propyl kriptofix 21 (SBNPK 21) and N-propyl kriptofix 22 (SBNPK 22) and subsequently immobilized with palladium nanoparticles (PNP-SBNPK 21 and PNP-SBNPK 22) to produce two new complexing lipophilic materials. Then these novel sorbents were applied for the enrichment of some metal ions and their subsequent determination by flame atomic absorption spectroscopy (FAAS). The influences of the variables including pH, amount of solid phase, sample flow rate, eluent conditions and sample volume on the metal ion recoveries were investigated. The detection limit of proposed method was in the interval 2.1–2.3 and 1.7–2.8 ng mL{sup −1} for PNP-SBNPK 21 and PNP-SBNPK 22 respectively, while the preconcentration factor was 80 for two sorbents. The relative standard deviations of recoveries were between 1.23–1.31 and 1.28–1.49 for PNP-SBNPK 21 and PNP-SBNPK 22 respectively. The method has high sorption-preconcentration efficiency even in the presence of various interfering ions. Due to the reasonable selectivity of proposed method, the relative standard deviation of recoveries of all understudied metal ions in some complicated matrices was less than 3.0%. Highlights: • Highly selective sorbents for solid phase extraction were synthesized. • The method has been successfully applied for the determination of trace metals ions. • Excellent properties of the sorbent have been illustrated in detail.

  10. Phosphorus and heavy metal extraction from wastewater treatment plant sludges using microwaves for generation of exceptional quality biosolids.

    Science.gov (United States)

    Danesh, Paymon; Hong, Seung M; Moon, Kyong W; Park, Jae K

    2008-09-01

    The objectives of this study were to evaluate the amount of phosphorus and metals in sludge that can be released into solution by microwave irradiation when applied to sludge before anaerobic digestion and determine the effectiveness of subsequent lime precipitation. The fraction of phosphorus in the soluble form increased to 23 to 28% for thickened sludge and to 31 to 38% for unthickened sludge, after raising temperatures by microwave heating to 50 to 70 degrees C. Microwave irradiation also caused the release of arsenic, molybdenum, nickel, and selenium into solution to 33, 15, 13, and 28% for thickened sludge and 63, 61, 37, and 27% for unthickened sludge, respectively. Microwave irradiation has been found to destruct pathogens in sludge to meet Class A biosolids requirements. Therefore, the reduction of phosphorus and metals in biosolids using microwave heating is economically attractive when considered as a secondary benefit to the use of microwave heating to generate Class A biosolids.

  11. β-Keto-enol Tethered Pyridine and Thiophene: Synthesis, Crystal Structure Determination and Its Organic Immobilization on Silica for Efficient Solid-Liquid Extraction of Heavy Metals.

    Science.gov (United States)

    Radi, Smaail; Tighadouini, Said; Bacquet, Maryse; Degoutin, Stephanie; Dacquin, Jean-Philippe; Eddike, Driss; Tillard, Monique; Mabkhot, Yahia N

    2016-07-07

    Molecules bearing β-keto-enol functionality are potential candidates for coordination chemistry. Reported herein is the first synthesis and use of a novel designed ligand based on β-keto-enol group embedded with pyridine and thiophene moieties. The product was prepared in a one-step procedure by mixed Claisen condensation and was characterized by EA, m/z, FT-IR, (¹H, (13)C) NMR and single-crystal X-ray diffraction analysis. The new structure was grafted onto silica particles to afford a chelating matrix which was well-characterized by EA, FT-IR, solid-state (13)C-NMR, BET, BJH, SEM and TGA. The newly prepared organic-inorganic material was used as an adsorbent for efficient solid-phase extraction (SPE) of Cu(II), Zn(II), Cd(II) and Pb(II) from aqueous solutions and showed a capture capacity of 104.12 mg·g(-1), 98.90 mg·g(-1), 72.02 mg·g(-1), and 65.54 mg·g(-1), respectively. The adsorption capacity was investigated, in a batch method, using time of contact, pH, initial concentration, kinetics (Langmuir and Freundlich models), and thermodynamic parameters (ΔG°, ΔH° and ΔS°) of the system effects.

  12. EDTA-enhanced phytoremediation of contaminated calcareous soils: heavy metal bioavailability, extractability, and uptake by maize and sesbania.

    Science.gov (United States)

    Suthar, Vishandas; Memon, Kazi Suleman; Mahmood-ul-Hassan, Muhammad

    2014-06-01

    Natural and chemically enhanced phytoextraction potentials of maize (Zea mays L.) and sesbania (Sesbania aculeata Willd.) were explored by growing them on two soils contaminated with heavy metals. The soils, Gujranwala (fine, loamy, mixed, hyperthermic Udic Haplustalf) and Pacca (fine, mixed, hyperthermic Ustollic Camborthid), were amended with varying amounts of ethylenediaminetetraacetic acid (EDTA) chelating agent, at 0, 1.25, 2.5, and 5.0 mM kg(-1) soil to enhance metal solubility. The EDTA was applied in two split applications at 46 and 60 days after sowing (DAS). The plants were harvested at 75 DAS. Addition of EDTA significantly increased the lead (Pb) and cadmium (Cd) concentrations in roots and shoots, uptake, bioconcentration factor, and phytoextraction rate over the control. Furthermore, addition of EDTA also significantly increased the soluble fractions of Pb and Cd in soil over the controls; the maximum increase of Pb and Cd was 13.1-fold and 3.1-fold, respectively, with addition of 5.0 mM EDTA kg(-1)soil. Similarly, the maximum Pb and Cd root and shoot concentrations, translocation, bioconcentration, and phytoextraction efficiency were observed at 5.0 mM EDTA kg(-1) soil. The results suggest that both crops can successfully be used for phytoremediation of metal-contaminated calcareous soils.

  13. Ecological risk assessment of boreal sediments affected by metal mining: Metal geochemistry, seasonality, and comparison of several risk assessment methods.

    Science.gov (United States)

    Väänänen, Kristiina; Kauppila, Tommi; Mäkinen, Jari; Leppänen, Matti T; Lyytikäinen, Merja; Akkanen, Jarkko

    2016-10-01

    The mining industry is a common source of environmental metal emissions, which cause long-lasting effects in aquatic ecosystems. Metal risk assessment is challenging due to variations in metal distribution, speciation, and bioavailability. Therefore, seasonal effects must be better understood, especially in boreal regions in which seasonal changes are large. We sampled 4 Finnish lakes and sediments affected by mining for metals and geochemical characteristics in autumn and late winter, to evaluate seasonal changes in metal behavior, the importance of seasonality in risk assessment, and the sensitivity and suitability of different risk assessment methods. We compared metal concentrations in sediment, overlying water, and porewater against environmental quality guidelines (EQGs). We also evaluated the toxicity of metal mixtures using simultaneously extracted metals and an acid volatile sulfides (SEM-AVS) approach together with water quality criteria (US Environmental Protection Agency equilibrium partitioning benchmarks). Finally, site-specific risks for 3 metals (Cu, Ni, Zn) were assessed using 2 biotic ligand models (BLMs). The metal concentrations in the impacted lakes were elevated. During winter stratification, the hypolimnetic O2 saturation levels were low (89%) and neutral pH (6.1-7.5) were found after the autumnal water overturn. Guidelines were the most conservative benchmark for showing an increased risk of toxicity in the all of the lakes. The situation remained stable between seasons. On the other hand, SEM-AVS, equilibrium partition sediment benchmarks (ESBs), and BLMs provided a clearer distinction between lakes and revealed a seasonal variation in risk among some of the lakes, which evidenced a higher risk during late winter. If a sediment risk assessment is based on the situation in the autumn, the overall risk may be underestimated. It is advisable to carry out sampling and risk assessment during periods in which metals are assumed to be the most

  14. Nondestructive SEM for surface and subsurface wafer imaging

    Science.gov (United States)

    Propst, Roy H.; Bagnell, C. Robert; Cole, Edward I., Jr.; Davies, Brian G.; Dibianca, Frank A.; Johnson, Darryl G.; Oxford, William V.; Smith, Craig A.

    1987-01-01

    The scanning electron microscope (SEM) is considered as a tool for both failure analysis as well as device characterization. A survey is made of various operational SEM modes and their applicability to image processing methods on semiconductor devices.

  15. The luminal surface of thyroid cysts in SEM

    DEFF Research Database (Denmark)

    Zelander, T; Kirkeby, S

    1978-01-01

    Four of the five kinds of cells constituting the walls of thyroid cysts can be identified in the SEM. These are cuboidal cells, mucous cells, cells with large granules and ciliated cells. A correlation between SEM and TEM observations is attempted.......Four of the five kinds of cells constituting the walls of thyroid cysts can be identified in the SEM. These are cuboidal cells, mucous cells, cells with large granules and ciliated cells. A correlation between SEM and TEM observations is attempted....

  16. Photomask Dimensional Metrology in the SEM: Has Anything Really Changed?

    Science.gov (United States)

    Postek, Michael T., Jr.; Vladar, Andras E.; Bennett, Marylyn H.

    2002-12-01

    Photomask dimensional metrology in the scanning electron microscope (SEM) has not evolved as rapidly as the metrology of resists and integrated circuit features on wafers. This has been due partly to the 4x (or 5x) reduction in the optical steppers and scanners used in the lithography process, and partly for the lesser need to account for the real three-dimensionality of the mask structures. So, where photomasks are concerned, many of the issues challenging wafer dimensional metrology at 1x are reduced by a factor of 4 or 5 and thus could be temporarily swept aside. This is rapidly changing with the introduction of advanced masks with optical proximity correction and phase shifting features used in 100 nm and smaller circuit generations. Fortunately, photomask metrology generally benefits from the advances made for wafer metrology, but there are still unique issues to be solved in this form of dimensional metrology. It is likely that no single metrology method or tool will ever provide all necessary answers. As with other types of metrology, resolution, sensitivity and linearity in the three-dimensional measurements of the shape of the lines and phase shifting features in general (width, height and wall angles) and the departures from the desired shape (surface and edge roughness, etc.) are the key parameters. Different methods and tools differ in their ability to collect averaged and localized signals with an acceptable speed, but in any case, application of this thorough knowledge of the physics of the given metrology is essential to extract the needed information. This paper will discuss the topics of precision, accuracy and traceability in the SEM metrology of photomasks. Current and possible new techniques utilized in the measurements of photomasks including charge suppression and highly accurate modeling for electron beam metrology will also be explored to answer the question "Has anything really changed?"

  17. Influence of the adsorption layers of surfactants on the extraction behaviour of heavy metals. Liquid-liquid extraction; Einfluss von Tensidadsorptionsschichten auf das Extraktionsverhalten von Schwermetallen. T. 1. Fluessig/fluessig-Extraktion

    Energy Technology Data Exchange (ETDEWEB)

    Raatz, S.; Haertel, G. [Technische Univ. Bergakademie Freiberg (Germany). Lehrstuhl fuer Umweltverfahrenstechnik

    1998-05-01

    Depending on the type of the head group (anionic, cationic and nonionic) as well as the structure the adsorption layers of surfactants on the liquid/liquid interface have an essential influence on the extraction behavior and the mass transfer of heavy metals (Cd, Zn, Pb, Cr). By choosing the right type and concentration of surfactant it should therefore be possible to accelerate the mass transfer thus improving the extraction rate (e.g. sodium dodecylsulfonate), or even to prevent a mass transfer almost completely (e.g. i-octylphenyl ethoxylate). The purpose of this paper is to control the selectivity of the mass-transfer accompanied by reaction beyond fluid interfaces with the help of surfactants as well as to clarify the effective mechanisms. (orig.) [Deutsch] Tensidadsorptionsschichten haben in Abhaengigkeit von der Art ihrer Kopfgruppierung (anionisch, kationisch und nichtionisch), Struktur und Konzentration einen wesentlichen Einfluss auf das Extraktionsverhalten bzw. den Stoffuebergang von Schwermetallen (Cd, Zn, Pb, Cr) ueber die Fluessig/fluessig-Phasengrenze. Mit der richtigen Wahl eines Tensids (Art, Konzentration) ist es daher moeglich, den Stofftransport zu beschleunigen und den Extraktionsgrad bedeutend zu verbessern (z.B. Na-Dodecylsulfonat) oder auch den Stofftransport nahezu zu unterbinden (z.B. i-Octylphenylethoxylat) oder auch den Stofftransport nahezu zu unterbinden (z.B. i-Octylphenylethoxylat). Das Ziel dieser Arbeit ist es, die Selektivitaet der reaktiven Stoffuebertragung ueber fluide Phasengrenzen durch entsprechend gewaehlte Adsorptionsschichten gezielt zu steuern und die dabei wirkenden Mechanismen aufzuklaeren. (orig.)

  18. Solvent extraction:The coordination chemistry behind extractive metallurgy

    OpenAIRE

    2014-01-01

    The modes of action of the commercial solvent extractants used in extractive hydrometallurgy are classified according to whether the recovery process involves the transport of metal cations, Mn+, metalate anions, MXxn-, or metal salts, MXx into a water-immiscible solvent. Well-established principles of coordination chemistry provide an explanation for the remarkable strengths and selectivities shown by most of these extractants. Reagents which achieve high selectivity when transporting metal ...

  19. In-situ tensile testing of propellant samples within SEM

    NARCIS (Netherlands)

    Benedetto, G.L. di; Ramshorst, M.C.J. van; Duvalois, W.; Hooijmeijer, P.A.; Heijden, A.E.D.M. van der; Klerk, W.P.C. de

    2015-01-01

    A tensile module system placed within a FEI NovaNanoSEM 650 Scanning Electron Microscope (SEM) was utilized in this work to conduct in-situ tensile testing of propellant material samples. This tensile module system allows for real-time in-situ SEM analysis of the samples to determine the failure mec

  20. Semântica e lexicografia

    Directory of Open Access Journals (Sweden)

    Julio Casares

    2001-01-01

    Full Text Available

    A Semântica e a Lexicografia se interpenetram mutuamente porque a Lexicografia não se limita a recolher as palavras do léxico, mas procura descrever a significação dos vocábulos e seus usos. O lexicógrafo também se ocupa de evolução dos sentidos das palavras para estabelecer a escala das acepções de um signo lexical. Casares conceitua acepção e discute o problema da discriminação das acepções e da sua ordenação no caso de palavras polissêmicas. Outra Questão delicada para o lexicógrafo é o reconhecimento e a identificação correta dos valores metafóricos. O autor usa como exemplo ilustrativo o verbete lat. ordo > esp. orden (port. ordem, signo polissêmico. Traça gráficos da ma-, lha de significações na semântica evolutiva dessa palavra, do étimo original latino ao espanhol moderno. Casares também trata do problema da lematização, ou seja, a decisão técnica de escolher como entrada de um dicionário, uma ou outra forma vocabular, o que envolve controvérsias permanentes em meio aos lexicólogos sobre as lexias (palavras complexas e como e quando se dá a categorização lexical de um polinómio vocabular. Esse problema é ampliado por causa da tradição caótica de muitas grafias, particularmente no caso de "locuções vocabulares". Advoga as vantagens e as virtudes de um dicionário que tivesse um índice de freqüência do uso de cada palavra, ou de cada acepção de um vocábulo.

  1. E