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Sample records for cadmium sulphide nanoparticles

  1. Algae mediated synthesis of cadmium sulphide nanoparticles and their application in bioremediation

    Science.gov (United States)

    Prasad Mandal, Ranju; Sekh, Sanoyaz; Sarkar, Neera Sen; Chattopadhyay, Dipankar; De, Swati

    2016-05-01

    The present work is a study on the biological synthesis of cadmium sulphide (CdS) nanoparticles using blue-green algae that is popularly used as a food supplement. This synthesis is unique in the sense that no external sulphur precursor is required, the CdS nanoparticles are synthesized in situ in the algal medium. The CdS nanoparticles thus synthesized are photoluminescent and can act as highly efficient photocatalysts for degradation of the dye pollutant malachite green. Thus the CdS nanoparticles synthesized in situ in the algae conform to the desired criteria of waste water treatment i.e. biosorption of the pollutant and its subsequent degradation. The novelty of this work also lies in its potential for use in bioremediation by conversion of the toxic Cd(II) ion to less toxic CdS nanoparticles within the algal framework.

  2. Synthesis and structural and optical characterization of Mn{sup 2+} doped cadmium sulphide nanoparticles stabilized in DETA matrix

    Energy Technology Data Exchange (ETDEWEB)

    Mercy, A.; Sakthi Murugesan, K. [PG and Research Department of Physics, Presidency College, Chennai 600 005, Tamil Nadu (India); Milton Boaz, B., E-mail: miltonboazcm@yahoo.co.in [PG and Research Department of Physics, Presidency College, Chennai 600 005, Tamil Nadu (India); Jesper Anandhi, A. [Department of Physics, Einstein College of Engineering, Tirunelveli 627 012, Tamil Nadu (India); Kanagadurai, R. [PG and Research Department of Physics, Presidency College, Chennai 600 005, Tamil Nadu (India)

    2013-03-25

    Highlights: ► Cadmium sulphide (CdS) nanoparticles doped with Mn{sup 2+} ions were successfully synthesized by chemical precipitation method at room temperature. ► Diethylene triamine matrix was found to be a suitable surfactant to keep the particle size stable. ► The optical properties of CdS nanoparticles doped with Mn{sup 2+} ions were found to be increased on varying the pH values. -- Abstract: Mn{sup 2+} doped cadmium sulphide nanoparticles were prepared with different pH values by chemical precipitation method, at room temperature. Diethylene triamine (DETA) was used as stabilizing agent to control the particle size and prevent agglomeration. The samples were characterized with X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM), energy dispersive X-ray analysis (EDAX), diffuse reflectance spectroscopy (DRS), Fourier transform infrared (FTIR) spectroscopy and photoluminescence (PL) studies. The average size of the Mn{sup 2+} doped cadmium sulphide nanoparticles, exhibits both cubic and hexagonal structure, calculated from Debye–Scherrer formula was of the order of 2–6 nm. The above value of the particle size was confirmed by using Williamson–Hall plot as well as Henglein’s formula. X-ray peak broadening analysis was done using Williamson–Hall plot. The HRSEM images showed the formation of nanoclusters and EDAX spectra confirms the presence of cadmium, sulphide and manganese elements in the sample. The DRS UV–vis spectra of the samples show blue shift, revealing the strong quantum confinement effect of nanoparticles. The formation of DETA capped Mn{sup 2+} doped CdS nanoparticles were confirmed by FTIR analysis. The synthesized samples show photoluminescence emission, ranging from 400 to 600 nm, in the visible region of the electromagnetic spectrum.

  3. Studies on cadmium sulphide nanoparticles formed by the Langmuir- Blodgett technique

    CERN Document Server

    Iwantono, M

    2003-01-01

    In this project, the formation and characterisation of CdS nanoparticles embedded within Langmuir-Blodgett (LB) films have been studied systematically. CdS nanoparticles were formed within calix[8]arene (CA) and stearic acid (SA) Cd-salt LB films by exposure to H sub 2 S gas at room temperature. The AFM images of the treated SA and CA bilayers show CdS clusters with lateral dimensions in the range of 20-30 nm and 10-15 nm, respectively. These particles are pseudo two-dimensional and have a shape of hexagonal platelets which is most likely consequence of their wurtzite structure. Calculations of the cluster thickness L sub z yield the value of 2 nm (Photoluminescence excitation-PLE) and 1.9 nm (UV-visible) for CdS clusters in SA matrix and two values of 1.2 nm and 1.6 nm (PLE) and 1.08 nm and 1.42 nm (UV-visible) for CA LB films. The PL spectra demonstrate a large Stokes shift, indicating the formation of 'dark excitons' in the platelet CdS clusters. The transformations of the absorption spectra caused by agei...

  4. Cadmium Sulphide-Reduced Graphene Oxide-Modified Photoelectrode-Based Photoelectrochemical Sensing Platform for Copper(II) Ions

    OpenAIRE

    Ibrahim, I.; Lim, H. N; N. M. Huang; Pandikumar, A

    2016-01-01

    A photoelectrochemical (PEC) sensor with excellent sensitivity and detection toward copper (II) ions (Cu2+) was developed using a cadmium sulphide-reduced graphene oxide (CdS-rGO) nanocomposite on an indium tin oxide (ITO) surface, with triethanolamine (TEA) used as the sacrificial electron donor. The CdS nanoparticles were initially synthesized via the aerosol-assisted chemical vapor deposition (AACVD) method using cadmium acetate and thiourea as the precursors to Cd2+ and S2-, respectively....

  5. Synthesis of cadmium sulphide in pure and mixed Langmuir-Blodgett films of -octadecylsuccinic acid

    Indian Academy of Sciences (India)

    G Hemakanthi; Balachandran Unni Nair; Aruna Dhathathreyan

    2000-04-01

    Cadmium sulphide (CdS) nanoparticles were grown by the reaction of sodium sulphide (Na2S) with Langmuir-Blodgett (LB) films of cadmium salts of -octadecylsuccinic acid (ODSU) and with LB films of ODSU in mixtures of octadecylamine and octadecyl alcohol. The results indicate that heterogeneous nucleation and aggregation in the pure ODSU LB films due to processes like Ostwald ripening are destabilized by the presence of the long-chain amine and alcohol in mixed systems. CdS nanoparticles in the LB films were monitored by UV-visible absorption spectra, which allow an estimation of the size of the particles. The morphology, size and nature of the nanocrystallites formed depend on whether the sulphidation was done on the pure film or in the mixed films. It is seen that particles of size around 1.6 nm were formed in ODSU/octadecylalcohol and ODSU/octadecylamine mixed LB films while in pure ODSU films the size was about 2.7 nm. These films showed typical needle-shaped structures, as observed by the optical microscopic technique. Mean size and morphology were confirmed by transmission and scanning electron microscopy, while selective area electron diffraction patterns showed six-fold symmetry and indicated that the CdS crystals grow epitaxially with respect to the monolayer. Further, the crystallisation enhanced in the mixed LB films showed a characteristic zinc oxide (Wurtzite) structure compared with the pure ODSU matrix.

  6. Growth of cadmium oxide whiskers on cadmium sulphide single crystals with copper as growth activator

    Energy Technology Data Exchange (ETDEWEB)

    Koparanova, N.; Simov, S. (Bylgarska Akademiya na Naukite, Sofia. Inst. po Fizika na Tvyrdoto Tyalo); Genchev, D. (Bylgarska Akademiya na Naukite, Sofia. Inst. za Yadrena Izsledvaniya i Yadrena Energetika); Metchenov, G. (Research Inst. of Criminalistics and Criminology, Sofia (Bulgaria))

    1985-02-01

    Some results on the growth and morphology of cadmium oxide whiskers, obtained on cadmium sulphide single crystals with copper as a growth activator, are presented in this work. Cadmium oxide whiskers have been obtained on brace 112-bar0 brace faces of cadmium sulphide plates with a copper layer deposited in advance. The whiskers grew during the annealing of the plates in a weak stream of technically pure argon at temperatures 670 to 730 deg C for 15 min to 3.5 h. Details about the procedure have been given elsewhere. The composition and morphology of the whiskers have been studied by an X-ray microanalyser JEOL 35 DDS and a scanning electron microscope JEOL, JSM 35. The optical microscopic observations have shown that after annealing, a gray-black granular layer is formed on the cadmium sulphide single crystals and this layer can easily be separated from the crystal substrate. Under the granular layer the crystal is heavily damaged. The whiskers grow on the granular layer and they are coloured yellow-brown or red-brown. The maximum whisker length attains several hundreds of micrometres and in some cases up to 1 mm or more.

  7. Synthesis, structural and property studies of Ni doped cadmium sulphide quantum dots stabilized in DETA matrix

    Energy Technology Data Exchange (ETDEWEB)

    Mercy, A. [PG and Research Department of Physics, Presidency College, Chennai 600 005, Tamil Nadu (India); Jesper Anandhi, A. [Department of Physics, Einstein College of Engineering, Tirunelveli 627 012, Tamil Nadu (India); Sakthi Murugesan, K. [PG and Research Department of Physics, Presidency College, Chennai 600 005, Tamil Nadu (India); Jayavel, R. [Centre for nanoscience and Technology, Anna University, Chennai 600 025, Tamil Nadu (India); Kanagadurai, R. [PG and Research Department of Physics, Presidency College, Chennai 600 005, Tamil Nadu (India); Milton Boaz, B., E-mail: miltonboazcm@yahoo.co.in [PG and Research Department of Physics, Presidency College, Chennai 600 005, Tamil Nadu (India)

    2014-04-01

    Highlights: • Ni doped CdS nanoparticles are synthesized by chemical precipitation method. • X-ray diffractogram confirms the formation of CdS with dopant. • FTIR spectrum reveals that the nanosamples are encapsulated by DETA. • The UV-VIS absorption spectra shows strong blue shift. - Abstract: Pure and Nickel doped cadmium sulphide nanoparticles at pH value 10 with three different concentrations have been synthesized by chemical precipitation method. Diethylene triamine was used as stabilizing agent to control the particle size as quantum dots without any agglomeration. The synthesized samples were characterized with X-ray diffraction (XRD), High resolution scanning electron microscopy (HRSEM), Energy dispersive X-ray analysis (EDAX), Transmission electron microscopy (TEM), Ultraviolet–Visible absorption spectroscopy (UV–VIS), Fourier transform infrared (FTIR) spectroscopy and photoluminescence (PL) studies. The nano crystalline nature of the as prepared samples is confirmed using XRD analysis. The average size of Ni doped cadmium sulphide nanoparticles calculated from Debye Scherer formula was of the order of 1.5–3 nm and that of pure CdS nanoparticles was of the order of 6–7 nm. The same value of the particle size was confirmed by using Williamson Hall plot as well as Henglein’s formula. X-ray peak broadening analysis was carried out using Williamson–Hall plot. The surface morphology studies of the sample using HRSEM images show the formation of nanoclusters and the EDAX spectra confirms the presence of cadmium sulphide and nickel elements in the sample. TEM images establish the stabilization of CdS nanoparticles in DETA. The UV–VIS absorption spectra of the sample show blue shift in the absorption region due to the quantum confinement effect. FTIR studies have been carried out to establish the presence of bonding by capping agent in the Ni doped samples. The synthesized samples show photoluminescence in the spectral region from 350 to 550

  8. Trichosporon jirovecii-mediated synthesis of cadmium sulfide nanoparticles.

    Science.gov (United States)

    El-Baz, Ashraf Farag; Sorour, Noha Mohamed; Shetaia, Youssria Mohamed

    2016-05-01

    Cadmium sulphide is one of the most promising materials for solar cells and of great interest due to its useful applications in photonics and electronics, thus the development of bio-mediated synthesis of cadmium sulphide nanoparticles (CdS NPs) is one of the essential areas in nanoparticles. The present study demonstrates for the first time the eco-friendly biosynthesis of CdS NPs using the yeast Trichosporon jirovecii. The biosynthesis of CdS NPs were confirmed by UV-Vis spectrum and characterized by X-ray diffraction assay and electron microscopy. Scanning and transmission electron microscope analyses shows the formation of spherical CdS NPs with a size range of about 6-15 nm with a mean Cd:S molar ratio of 1.0:0.98. T. jirovecii produced hydrogen sulfide on cysteine containing medium confirmed by positive cysteine-desulfhydrase activity and the colony color turned yellow on 0.1 mM cadmium containing medium. T. jirovecii tolerance to cadmium was increased by the UV treatment and three 0.6 mM cadmium tolerant mutants were generated upon the UV radiation treatment. The overall results indicated that T. jirovecii could tolerate cadmium toxicity by its conversion into CdS NPs on cysteine containing medium using cysteine-desulfhydrase as a defense response mechanism. PMID:26467054

  9. Electron Microscopy and Optical Characterization of Cadmium Sulphide Nanocrystals Deposited on the Patterned Surface of Diatom Biosilica

    Directory of Open Access Journals (Sweden)

    Timothy Gutu

    2009-01-01

    Full Text Available Intricately patterned biosilica obtained from the shell of unicellular algae called diatoms serve as novel templates for fabrication of optoelectronic nanostructures. In this study, the surface of diatom frustules that possessed hierarchical architecture ordered at the micro and nanoscale was coated with a nanostructured polycrystalline cadmium sulphide (CdS thin film using a chemical bath deposition technique. The CdS thin film was composed of spherical nanoparticles with a diameter of about 75 nm. The CdS nanoparticle thin film imparted new photoluminescent properties to the intricately patterned diatom nanostructure. The imparted photoluminescent properties were dependent on the CdS coverage onto the frustules surface. The intrinsic photoluminescent properties of the frustules were strongly quenched by the deposited CdS. The origin of PL spectra was discussed on the basis of the band theory and native defects.

  10. a Study of Volatile Precursors for the Growth of Cadmium Sulphide and Cadmium Selenide by Metal Organic Chemical Vapour Deposition.

    Science.gov (United States)

    Beer, Michael P.

    Available from UMI in association with The British Library. The wide-band-gap semiconductors, cadmium sulphide and cadmium selenide, may be grown by Metal Organic Chemical Vapour Deposition (MOCVD). This method typically involves the reaction of gaseous streams of Me_2 Cd and H_2Y (Y = S, Se) over a heated substrate (usually gallium arsenide) on which the desired compound is grown as an epitaxial layer. Unfortunately, the precursors start to react in the cold zone of the reactor, that is before they reach the heated substrate. This problem is known as prereaction. The problem of prereaction is partially reduced by the use of adducts of dimethyl cadmium in place of the free dialkyl compound although the mechanism by which such adducts block prereaction is unknown. Accordingly, a study of adducts of dimethyl cadmium was undertaken with a view to determining their properties in all phases. The adduct of Me_2Cd with 2,2^ '-bipyridyl was found to be monomeric in the solid state while that with 1,4-dioxane, a volatile compound used for prereaction reduction, was found to be polymeric. A study of adducts in the gas phase using mass spectrometry and gas phase Fourier transform infrared spectroscopy gave no evidence to suggest there is any gas phase association between 1,4-dioxane and dimethyl cadmium. With the 2,2 ^'-bipyridyl adduct some evidence for partial retention of coordinate bonds upon sublimation was obtained. The solid adduct of Me _2Cd with N,N,N^' ,N^'-tetramethylethylenediamine (TMEDA) was prepared as it was hoped that the flexibility of the aliphatic Lewis base would permit the formation of an adduct containing strong co-ordinate bonds which would remain intact upon sublimation. Using gas phase electron diffraction, the structure of the adduct of Me_2Cd and TMEDA was determined. It was shown to exist in the gas phase purely as the associated monomeric species. The adduct was then employed for the growth of CdS and CdSe in an industrial MOCVD apparatus. The

  11. Dynamic protein coronas revealed as a modulator of silver nanoparticle sulphidation in vitro

    Science.gov (United States)

    Miclăuş, Teodora; Beer, Christiane; Chevallier, Jacques; Scavenius, Carsten; Bochenkov, Vladimir E.; Enghild, Jan J.; Sutherland, Duncan S.

    2016-06-01

    Proteins adsorbing at nanoparticles have been proposed as critical toxicity mediators and are included in ongoing efforts to develop predictive tools for safety assessment. Strongly attached proteins can be isolated, identified and correlated to changes in nanoparticle state, cellular association or toxicity. Weakly attached, rapidly exchanging proteins are also present at nanoparticles, but are difficult to isolate and have hardly been examined. Here we study rapidly exchanging proteins and show for the first time that they have a strong modulatory effect on the biotransformation of silver nanoparticles. Released silver ions, known for their role in particle toxicity, are found to be trapped as silver sulphide nanocrystals within the protein corona at silver nanoparticles in serum-containing cell culture media. The strongly attached corona acts as a site for sulphidation, while the weakly attached proteins reduce nanocrystal formation in a serum-concentration-dependent manner. Sulphidation results in decreased toxicity of Ag NPs.

  12. Growth and characterization of oriented cadmium sulphide nanocrystals under Langmuir-Blodgett monolayer of arachidic acid

    Science.gov (United States)

    Roy, U. N.; Ingale, A.; Kukreja, L. M.; Mishra, S.; Ganesan, V.; Rustagi, K. C.

    Cadmium sulphide nanocrystals were grown at room temperature (20 °C) under arachidic acid monolayers floating over an aqueous solution of CdCl2 inside an enclosed Langmuir-Blodgett set-up, through slow infusion of H2S gas. X-ray diffraction spectra suggest an oriented growth of the crystallites. The particle sizes were found to increase with duration of exposure to the H2S gas. Atomic force microscopy indicated that the particles were nearly circular pellets with uniform morphology throughout. In Raman spectra, the FWHM of the LO phonon was found to be large ( 20 cm-1) for all the films grown with different exposure times in H2S gas, and was found to reduce to 8 cm-1 after annealing a typical sample at 500 °C for 45 min.

  13. Combustion synthesis of cadmium sulphide nanomaterials for efficient visible light driven hydrogen production from water

    Indian Academy of Sciences (India)

    A Daya Mani; N Xanthopoulos; Daniele Laub; C H Subrahmanyam

    2014-07-01

    Anion-doped cadmium sulphide nanomaterials have been synthesized by using combustionmethod at normal atmospheric conditions. Oxidant/fuel ratios have been optimized in order to obtain CdS with best characteristics. Formation of CdS and size of crystallite were identified by X-ray diffraction and confirmed by transmission electron microscopy. X-ray photoelectron spectroscopy confirmed the presence of C and N in the CdS matrix. The observed enhanced photocatalytic activity of the CdS nanomaterials for the hydrogen production from water (2120 mol/h) can be attributed to high crystallinity, low band gap and less exciton recombination due to the C and N doping.

  14. Photocatalytically active colloidal platinum-decorated cadmium sulphide nanorods for hydrogen production; Photokatalytisch Aktive Kolloidale Platindekorierte Cadmiumsulfidnanostaebchen zur Wasserstoffproduktion

    Energy Technology Data Exchange (ETDEWEB)

    Berr, Maximilian Josef

    2012-12-07

    This is the first study to have been successful in producing hydrogen by means of photocatalytically active colloidal semiconductor particles. Specifically, colloidal platinum-decorated cadmium sulphide nanorods were used to reduce water to hydrogen. Oxidation of water to oxygen was substituted by addition of a reducing agent (hole collector), e.g. sulphite, which itself is oxidised to sulphate by the photohole. During photochemical platinum decoration it was discovered that in addition to the expected platinum nanoparticles there had also formed platinum clusters in the subnanometer range. In spite of the small quantity of platinum deposited on the nanorods these clusters showed the same quantum efficiency as the intended product. [German] In dieser Arbeit wurde erstmals mit kolloidalen Halbleiternanopartikeln photokatalytische Wasserstoffproduktion erzielt. Im Detail wurde Wasser mit kolloidalen, platindekorierten Cadmiumsulfidnanostaebchen zu Wasserstoff reduziert. Die Oxidation des Wasser zu Sauerstoff wurde durch Zugabe eines Reduktionsmittels (Lochfaenger) substituiert, z.B. Sulfit, das durch das Photoloch zu Sulfat reduziert wird. Bei der photochemischen Platindekoration wurden neben den erwarteten Platinnanopartikeln mit 4 - 5 nm Durchmesser auch Subnanometer grosse Platincluster entdeckt, die trotz der geringeren Menge an deponierten Platin auf den Nanostaebchen die gleiche Quanteneffizienz demonstrieren.

  15. Cadmium Sulphide-Reduced Graphene Oxide-Modified Photoelectrode-Based Photoelectrochemical Sensing Platform for Copper(II) Ions

    Science.gov (United States)

    Ibrahim, I; Lim, H. N; Huang, N. M; Pandikumar, A

    2016-01-01

    A photoelectrochemical (PEC) sensor with excellent sensitivity and detection toward copper (II) ions (Cu2+) was developed using a cadmium sulphide-reduced graphene oxide (CdS-rGO) nanocomposite on an indium tin oxide (ITO) surface, with triethanolamine (TEA) used as the sacrificial electron donor. The CdS nanoparticles were initially synthesized via the aerosol-assisted chemical vapor deposition (AACVD) method using cadmium acetate and thiourea as the precursors to Cd2+ and S2-, respectively. Graphene oxide (GO) was then dip-coated onto the CdS electrode and sintered under an argon gas flow (50 mL/min) for the reduction process. The nanostructured CdS was adhered securely to the ITO by a continuous network of rGO that also acted as an avenue to intensify the transfer of electrons from the conduction band of CdS. The photoelectrochemical results indicated that the ITO/CdS-rGO photoelectrode could facilitate broad UV-visible light absorption, which would lead to a higher and steady-state photocurrent response in the presence of TEA in 0.1 M KCl. The photocurrent decreased with an increase in the concentration of Cu2+ ions. The photoelectrode response for Cu2+ ion detection had a linear range of 0.5–120 μM, with a limit of detection (LoD) of 16 nM. The proposed PEC sensor displayed ultra-sensitivity and good selectivity toward Cu2+ ion detection. PMID:27176635

  16. Cadmium Sulphide-Reduced Graphene Oxide-Modified Photoelectrode-Based Photoelectrochemical Sensing Platform for Copper(II) Ions.

    Science.gov (United States)

    Ibrahim, I; Lim, H N; Huang, N M; Pandikumar, A

    2016-01-01

    A photoelectrochemical (PEC) sensor with excellent sensitivity and detection toward copper (II) ions (Cu2+) was developed using a cadmium sulphide-reduced graphene oxide (CdS-rGO) nanocomposite on an indium tin oxide (ITO) surface, with triethanolamine (TEA) used as the sacrificial electron donor. The CdS nanoparticles were initially synthesized via the aerosol-assisted chemical vapor deposition (AACVD) method using cadmium acetate and thiourea as the precursors to Cd2+ and S2-, respectively. Graphene oxide (GO) was then dip-coated onto the CdS electrode and sintered under an argon gas flow (50 mL/min) for the reduction process. The nanostructured CdS was adhered securely to the ITO by a continuous network of rGO that also acted as an avenue to intensify the transfer of electrons from the conduction band of CdS. The photoelectrochemical results indicated that the ITO/CdS-rGO photoelectrode could facilitate broad UV-visible light absorption, which would lead to a higher and steady-state photocurrent response in the presence of TEA in 0.1 M KCl. The photocurrent decreased with an increase in the concentration of Cu2+ ions. The photoelectrode response for Cu2+ ion detection had a linear range of 0.5-120 μM, with a limit of detection (LoD) of 16 nM. The proposed PEC sensor displayed ultra-sensitivity and good selectivity toward Cu2+ ion detection. PMID:27176635

  17. Cadmium Sulphide-Reduced Graphene Oxide-Modified Photoelectrode-Based Photoelectrochemical Sensing Platform for Copper(II Ions.

    Directory of Open Access Journals (Sweden)

    I Ibrahim

    Full Text Available A photoelectrochemical (PEC sensor with excellent sensitivity and detection toward copper (II ions (Cu2+ was developed using a cadmium sulphide-reduced graphene oxide (CdS-rGO nanocomposite on an indium tin oxide (ITO surface, with triethanolamine (TEA used as the sacrificial electron donor. The CdS nanoparticles were initially synthesized via the aerosol-assisted chemical vapor deposition (AACVD method using cadmium acetate and thiourea as the precursors to Cd2+ and S2-, respectively. Graphene oxide (GO was then dip-coated onto the CdS electrode and sintered under an argon gas flow (50 mL/min for the reduction process. The nanostructured CdS was adhered securely to the ITO by a continuous network of rGO that also acted as an avenue to intensify the transfer of electrons from the conduction band of CdS. The photoelectrochemical results indicated that the ITO/CdS-rGO photoelectrode could facilitate broad UV-visible light absorption, which would lead to a higher and steady-state photocurrent response in the presence of TEA in 0.1 M KCl. The photocurrent decreased with an increase in the concentration of Cu2+ ions. The photoelectrode response for Cu2+ ion detection had a linear range of 0.5-120 μM, with a limit of detection (LoD of 16 nM. The proposed PEC sensor displayed ultra-sensitivity and good selectivity toward Cu2+ ion detection.

  18. Inorganic Nanoparticle-Modified Poly(Phenylene Sulphide)/ Carbon Fiber Laminates: Thermomechanical Behaviour

    OpenAIRE

    Díez-Pascual, Ana M.; Mohammed Naffakh

    2013-01-01

    Carbon fiber (CF)-reinforced high-temperature thermoplastics such as poly(phenylene sulphide) (PPS) are widely used in structural composites for aerospace and automotive applications. The porosity of CF-reinforced polymers is a very important topic for practical applications since there is a direct correlation between void content and mechanical properties. In this study, inorganic fullerene-like tungsten disulphide (IF-WS2) lubricant nanoparticles were used to manufacture PPS/IF-WS2/CF lamin...

  19. Glassy carbon/multi walled carbon nanotube/cadmium sulphide photoanode for light energy storage in vanadium photoelectrochemical cell

    Science.gov (United States)

    Peimanifard, Zahra; Rashid-Nadimi, Sahar

    2015-12-01

    The aim of this study is utilizing the artificial photosynthesis, which is an attractive and challenging theme in the photoelectrocatalytic water splitting, to charge the vanadium redox flow battery (VRFB). In this work multi walled carbon nanotube/cadmium sulphide hybrid is employed as a photoanode material to oxidize VO2+ to VO2+ for charging the positive vanadium redox flow battery's half-cell. Characterization studies are also described using the scanning electron microscopic-energy-dispersive X-ray spectroscopy (SEM-EDS), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and UV-Visible methods. The phtoelectrochemical performance is characterized by cyclic voltammetry and chronoamperometry. Applied bias photon-to-current efficiency (ABPE) is achieved for both two and three-electrode configurations. The glassy carbon/multi walled carbon nanotube/cadmium sulphide yields high maximum ABPE of 2.6% and 2.12% in three and two-electrode setups, respectively. These results provide a useful guideline in designing photoelectrochemical cells for charging the vanadium redox flow batteries by sunlight as a low cost, free and abundant energy source, which does not rely on an external power input.

  20. Crystallographic, optical and electrical properties of low zinc content cadmium zinc sulphide composite thin films for photovoltaic applications

    International Nuclear Information System (INIS)

    Graphical abstract: The DC conductivity of the screen-printed Cd0.9Zn0.1S films was measured in vacuum by a two probe technique. The plot of ln σDC against 1000/T for Cd0.9Zn0.1S film is a straight line indicating that conduction in the film is through thermally activated process. Highlights: ► The method of preparing films of low zinc content i.e. Cd0.9Zn0.1S alloy by screen printing method is cost effective and reasonably accurate. ► The structural, optical and electrical studies of these films indicate that the films are quite suitable for photovoltaic device fabrication. ► The prepared films of Cd0.9Zn0.1S alloy are found to be polycrystalline in nature and have hexagonal (wurtzite) structure. ► The absorption coefficient of these films is high and is suitable for efficient absorption in the visible region of solar spectrum. ► It has been observed that the conduction in Cd0.9Zn0.1S films is through thermally activated process. - Abstract: In this paper a screen-printing method has been employed for the deposition of low zinc content cadmium zinc sulphide (Cd0.9Zn0.1S) composite thin films on ultra clean glass substrate. Cadmium sulphide, zinc sulphide and cadmium chloride have been used as the basic source material. With these basic source materials, the optimum conditions for preparing good quality screen-printed films have been found. X-ray diffraction studies revealed that the films are polycrystalline in nature, single phase exhibiting wurtzite (hexagonal) structure with strong preferential orientation of grains along the (1 0 1) direction. SEM/EDAX analysis confirms the formation of ternary compound. The optical band gap (Eg) of the films has been studied by using reflection spectra in wavelength range 350–600 nm. The DC conductivity of the films has been measured in vacuum by a two probe technique.

  1. In-situ fabrication of cobalt oxide / sulphide mixed phase nanoparticles in Polyphenylenesulphide matrix

    Directory of Open Access Journals (Sweden)

    Narendra Rumale

    2013-03-01

    Full Text Available A novel approach for the in-situ fabrication of combined cobalt oxide / sulphide nanoparticles in sulphur containing polymer polyphenylenesulphide (PPS by polymer inorganic solid-solid reaction technique is reported here. At present, there is considerable interest in polymer-metal chalcogenides / oxides based nano-composites on account of their optical, magnetic, electronic and catalytic properties. We have demonstrated the suitability of solid-solid reaction methodology by reacting commonly available cobalt precursors with engineering thermoplastic PPS. The cobalt precursor was reacted with PPS in 1:1, 1:5, 1:10, and 1:15 molar ratios, respectively, by heating the mixture at the melting temperature of the polymer (285 ºC for six hours. The resultant products were characterized by X-ray diffractometry (XRD, Field-emission scanning electron microscopy (FESEM, Thermogravimetric analysis (TGA, Differential scanning calorimetry (DSC, Diffuse reflectance spectroscopy (DRS techniques and High resolution transmission electron microscope (HRTEM. The shift in melting temperature of PPS was observed. Increase in absorption peak is observed in the range of 320 to 370 nm with the increase in PPS concentration. Resultant nanoparticles of cobalt sulphide and cobalt oxide embedded in the PPS matrix showed spherical and distorted rod like morphology.

  2. Localized surface plasmon and exciton interaction in silver-coated cadmium sulphide quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, P.; Rustagi, K. C.; Vasa, P.; Singh, B. P., E-mail: bhanuprs@gmail.com [Department of Physics, Indian Institute of Technology Bombay, Mumbai- 400076 (India)

    2015-05-15

    Localized surface plasmon and exciton coupling has been investigated on colloidal solutions of silver-coated CdS nanoparticles (NPs), synthesized by gamma irradiation. Two broad photoluminescence (PL) bands (blue/red) corresponding to band to band and defect state transitions have been observed for the bare and coated samples. In case of bare CdS NPs, the intensity of the red PL peak is about ten times higher than the blue PL peak intensity. However, on coating the CdS NPs with silver, the peak intensity of the blue PL band gets enhanced and becomes equal to that of the red PL band. High-resolution transmission electron microscopic (HRTEM) images adequately demonstrate size distribution of these metal/semiconductor nanocomposites. UV-Vis absorption studies show quantum confinement effect in these semiconductor quantum dot (SQD) systems. Absorption spectrum of silver-coated SQDs shows signature of surface plasmon-exciton coupling which has been theoretically verified.

  3. Localized surface plasmon and exciton interaction in silver-coated cadmium sulphide quantum dots

    Science.gov (United States)

    Ghosh, P.; Rustagi, K. C.; Vasa, P.; Singh, B. P.

    2015-05-01

    Localized surface plasmon and exciton coupling has been investigated on colloidal solutions of silver-coated CdS nanoparticles (NPs), synthesized by gamma irradiation. Two broad photoluminescence (PL) bands (blue/red) corresponding to band to band and defect state transitions have been observed for the bare and coated samples. In case of bare CdS NPs, the intensity of the red PL peak is about ten times higher than the blue PL peak intensity. However, on coating the CdS NPs with silver, the peak intensity of the blue PL band gets enhanced and becomes equal to that of the red PL band. High-resolution transmission electron microscopic (HRTEM) images adequately demonstrate size distribution of these metal/semiconductor nanocomposites. UV-Vis absorption studies show quantum confinement effect in these semiconductor quantum dot (SQD) systems. Absorption spectrum of silver-coated SQDs shows signature of surface plasmon-exciton coupling which has been theoretically verified.

  4. Inorganic Nanoparticle-Modified Poly(Phenylene Sulphide/ Carbon Fiber Laminates: Thermomechanical Behaviour

    Directory of Open Access Journals (Sweden)

    Ana M. Díez-Pascual

    2013-07-01

    Full Text Available Carbon fiber (CF-reinforced high-temperature thermoplastics such as poly(phenylene sulphide (PPS are widely used in structural composites for aerospace and automotive applications. The porosity of CF-reinforced polymers is a very important topic for practical applications since there is a direct correlation between void content and mechanical properties. In this study, inorganic fullerene-like tungsten disulphide (IF-WS2 lubricant nanoparticles were used to manufacture PPS/IF-WS2/CF laminates via melt-blending and hot-press processing, and the effect of IF-WS2 loading on the quality, thermal and mechanical behaviour of the hybrid composites was investigated. The addition of IF-WS2 improved fiber impregnation, resulting in lower degree of porosity and increased delamination resistance, compression and flexural properties; their reinforcement effect was greater at temperatures above the glass transition (Tg. IF-WS2 contents higher than 0.5 wt % increased Tg and the heat deflection temperature while reduced the coefficient of thermal expansion. The multiscale laminates exhibited higher ignition point and notably reduced peak heat release rate compared to PPS/CF. The coexistence of micro- and nano-scale fillers resulted in synergistic effects that enhanced the stiffness, strength, thermal conductivity and flame retardancy of the matrix. The results presented herein demonstrate that the IF-WS2 are very promising nanofillers to improve the thermomechanical properties of conventional thermoplastic/CF composites.

  5. Growth of gold/zinc sulphide multilayer films using layer-by-layer assembly of colloidal nanoparticles

    Science.gov (United States)

    Promnimit, S.; Cavelius, C.; Mathur, S.; Dutta, J.

    2008-12-01

    Fabrication of multilayer thin films through layer-by-layer (lbl) deposition of charged nanoparticles on tin-doped indium oxide (ITO) coated and uncoated glass substrates are reported. The thin films were constructed by alternately dipping a substrate into a colloidal suspension of chitosan capped zinc sulphide (ZnS) nanoparticles (∼30 nm) and citrate stabilized colloidal gold (Au) nanoparticles (∼20 nm) leading to electrostatic interactions between the oppositely charged nanoparticle layers. Thin films consisting of up to 200 deposition cycles by multiple dipping have been studied and surface morphology, changes in the optical absorption characteristics, thickness, uniformity, roughness and electrical characteristics are reported. The multilayered assemblies, attached to the surface by strong ionic bonds, were highly stable and could not be removed by moderate scratching. The current-voltage characteristics in the forward and reverse bias conditions demonstrated rectifying behaviors in the onset of conduction voltage which makes these films attractive for future electronic devices.

  6. Preparation of cu/fes nanoparticles by mechanochemical reduction of copper sulphide

    DEFF Research Database (Denmark)

    Balaz, P.; Takacs, L.; Jiang, Jianzhong;

    2002-01-01

    The mechanochemical reduction of copper sulphide with elemental iron was studied. The methods of XPS, SEM, EDX, and low temperature nitrogen sorption were used to analyse the surface composition and the composite particles formed from elemental copper and hexagonal 2C-troilite. The study...

  7. Facile synthesis and post-processing of eco-friendly, highly conductive copper zinc tin sulphide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Rameez; Distaso, Monica, E-mail: monica.distaso@lfg.fau.de [Friedrich-Alexander-Universitaet Erlangen-Nuernberg (FAU), Institute of Particle Technology (Germany); Azimi, Hamed; Brabec, Christoph J. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg (FAU), Institute of Materials for Electronics and Energy Technology (I-MEET) (Germany); Peukert, Wolfgang, E-mail: w.peukert@lfg.fau.de [Friedrich-Alexander-Universitaet Erlangen-Nuernberg (FAU), Institute of Particle Technology (Germany)

    2013-09-15

    Cu{sub 2}ZnSnS{sub 4} (CZTS) nanoparticles have shown promising properties to be used as an energy harvesting material. They are usually synthesised under inert atmosphere or vacuum, whereas the subsequent step of film formation is carried out under an atmosphere of sulphur and/or Sn in order to avoid the decomposition of CZTS nanoparticles into binary and ternary species as well as the formation of the corresponding oxides. In the present paper we show that both the synthesis of CZTS nanoparticles and the film formation from the corresponding suspension can be considerably simplified. Namely, the synthesis can be carried out without controlling the atmosphere, whereas during the film annealing a nitrogen atmosphere is sufficient to avoid the depletion of the CZTS kesterite phase. Furthermore, an integrated approach including in-depth Raman analysis is developed in order to deal with the challenges associated with the characterization of CZTS nanoparticles in comparison to bulk systems. The formation of competitive compounds during the synthesis such as binary and ternary sulphides as well as metal oxides nanoparticles is discussed in detail. Finally, the as-produced films have ten times higher conductivity than the state of the art.

  8. The effect of thermal annealing on the optical band gap of cadmium sulphide thin films, prepared by the chemical bath deposition technique

    International Nuclear Information System (INIS)

    Cadmium sulphide thin films have been prepared by the chemical bath deposition technique (ph 11, 70 degree centigrade). Two different sets of films were prepared under varied conditions and concentrations of their ions sources (Cd2+ from cadmium nitrate, S2- from thiourea) and Na2EDTA as a complexing agent. A UV mini-Schimazu UV-VIS Spectrophotometer was used to determine the optical absorbance of the films as a function of wavelength at room temperature over the wavelength range 200 - 600 nm. The samples were then thermally annealed for thirty minutes, at temperatures of 100 degree centigrade, and 200 degree centigrade, after which the absorbance of the films were again recorded. The band gap values obtained for the sample with 0.5 M CdS as deposited, annealed at 100 degree centigrade and 200 degree centigrade were 2.1 eV, 2.2 eV and 2.3 eV respectively. Whilst the values obtained for the sample 0.15 CdS as deposited, annealed at 100 degree centigrade and annealed at 200 degree centigrade were 2.0 eV, 2.01 eV and 2.02 eV respectively. The increase in band gap with annealing temperature might be attributed to the improvement in crystallinity in the films. (au)

  9. Microbially Mediated-Precipitation of Cadmium Carbonate Nanoparticles.

    Science.gov (United States)

    Kang, Serku; Kim, Yumi; Lee, Youngjae; Rohl, Yul

    2015-01-01

    The objectives of this study were to investigate the microbially mediated precipitation of cadmium using microorganisms enriched from rhodoliths and to characterize the mineralogical properties of the precipitates. A 16S rRNA sequence analysis showed the enriched microorganisms contained carbonate forming microorganisms such as Proteus mirabilis. The microorganisms mediated Cd-precipitation with Cd-acetate, but no precipitates were formed without the microbes in D-1 medium. XRD analysis showed the precipitates were poorly crystalline Cd-carbonates (CdCO3). SEM and TEM-EDS analyses showed that the Cd-carbonate minerals were irregular in shape, 20-30 nm in size, and composed of C, O, and Cd. Therefore, microbially mediated precipitation of cadmium carbonates could be used as a precursor of CdO nanoparticles and could play an important role in Cd immobilization in Cd-contaminated water as well as CO2 fixation in natural environments.

  10. Dichloro (bis[diphenylthiourea] cadmium complex as a precursor for HDA-capped CdS nanoparticles and their solubility in water

    Directory of Open Access Journals (Sweden)

    Tshinyadzo R. Tshikhudo

    2010-07-01

    Full Text Available A single-source precursor route has been explored by using the diphenylthiourea cadmium complex as the source of cadmium sulphide (CdS nanoparticles. The reaction was carried out using hexadecylamine (HDA as the solvent and stabilising agent for the particles. The phenylthiourea complex was synthesised and characterised by means of a combination of spectroscopic techniques, microanalysis and X-ray crystal structural analysis. The diphenylthiourea complex was thermolysed in HDA at 120 °C for 1 h to produce CdS nanoparticles. The CdS nanoparticles prepared were made water-soluble via a ligand exchange reaction involving the use of pyridine to displace HDA. The pyridine was, in turn, replaced by glucose and glucuronic acid. The absorption and emission spectra showed the typical features of quantum confinement for the nanoparticles for both HDA-capped and glucose- or glucuronic acid-capped CdS nanoparticles. The change in the capping groups, from HDA to glucose and glucuronic acid, resulted in absorption and emission features that were almost similar, with only slight red-shifting and tailing.

  11. Synthesis, Structural and Optical Properties of TOPO and HDA Capped Cadmium Sulphide Nanocrystals, and the Effect of Capping Ligand Concentration

    Directory of Open Access Journals (Sweden)

    Damian C. Onwudiwe

    2015-01-01

    Full Text Available The thermal decomposition of bis(N,N-diallyldithiocarbamatoCd(II in a “one-pot” synthesis in tri-n-octylphosphine oxide (TOPO and hexadecylamine (HDA afforded CdS (TOPO-CdS and HDA-CdS of varying optical properties and morphologies. The influence of the ratio of the precursor concentration to the capping molecule, as a factor affecting the morphology and size of the nanoparticles, was investigated. The particles varied in shape from spheres to rods and show quantum size effects in their optical spectra with clear differences in the photoluminescence (PL spectra. The PL spectrum of the HDA capped CdS nanoparticles has an emission maximum centred at 468, 472, and 484 nm for the precursor to HDA concentration ratio of 1 : 10, 1 : 15, and 1 : 20, respectively, while the TOPO capped nanoparticles show emission peaks at 483, 494, and 498 nm at the same concentration ratio. Powdered X-ray diffraction (p-XRD shows the nanoparticles to be hexagonal. The crystallinity of the nanoparticles was evident from high resolution transmission electron microscopy (HRTEM which gave well-defined images of particles with clear lattice fringes.

  12. Comparison of antibacterial activities of cadmium oxide nanoparticles against Pseudomonas Aeruginosa and Staphylococcus Aureus bacteria

    Directory of Open Access Journals (Sweden)

    Bahareh Salehi

    2015-01-01

    Conclusion: This study showed that antibacterial effects of cadmium oxide nanoparticles on positive gram bacteria are stronger than negative gram bacteria and antibacterial effects of cdo nanoparticles against both bacteria, but Staphylococcus aureus bacteria were more sensitive to nanoparticles as compared to Pseudomonas aeruginosa.

  13. Chemical Precipitation Synthesis of Ferric Chloride Doped Zinc Sulphide Nanoparticles and Their Characterization Studies

    CERN Document Server

    Theivasanthi, T; Alagar, M; 10.7598/cst2013.207

    2013-01-01

    Nanoparticles of Ferric Chloride doped ZnS has been synthesized by simple chemical precipitation method and characterized by XRD, SEM, UV-Vis analysis, Differential Thermal Analysis, Thermo Gravimetric Analysis and Differential Scanning Calorimetry. XRD patterns of the samples reveal particle size, specific surface area and the formation of cubic structure. The SEM images show that the cauliflower likes structure. Optical band gap values have been obtained from UV-Vis absorption spectra. It has also been found that energy band gap (Eg) increases with the increase in molar concentration of reactant solution. Thermal analysis measurement of the prepared sample shows that the thermal stability of pure ZnS is decreased due to increase in Ferric Chloride concentration. Undoped ZnS is more thermal stable when compared to FeCl3 doped ZnS.

  14. Optimization of adsorption process of Cadmium ions from synthetic wastewater using synthesized iron magnetic nanoparticles (Fe3O4

    Directory of Open Access Journals (Sweden)

    Leila Karimi Takanlu

    2014-10-01

    Conclusion: Magnetite nanoparticles exhibit high capability for removal of cadmium. The nanoparticles synthesized could be used at industrial scale because of having the magnetic property, which make them easily recovered from aqueous solution through applying a magnetic field.

  15. Structural and magnetic studies on heavy-metal-adsorbing iron sulphide nanoparticles produced by sulphate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Watson, J.H.P; Cressey, B.A.; Roberts, A.P.; Ellwood, D.C.; Charnock, J.M.; Soper, A.K

    2000-05-01

    In previous and in work to be published, it has been shown that iron sulphide material, produced by sulphate-reducing bacteria (SRB), is an excellent adsorbent for a wide range of heavy metals. The material adsorbs between 100 and 400 mg g{sup -1} and residual levels in solutions can be of the order of pg per litre. Further, strongly magnetic forms of this material can now be produced which can be effectively and cheaply removed from suspension together with the adsorbate by magnetic separation. This paper examines the structure of weakly magnetic and strongly magnetic iron sulphide material produced by SRB with a view to increasing the understanding of its adsorbent and the magnetic properties. The structural properties have been examined using high-resolution imaging and electron diffraction in a transmission electron microscope (TEM), the measurements of magnetisation versus field and temperature, extended X-ray absorption fine-structure (EXAFS) spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy and neutron diffraction. Before drying the surface area of both the weakly magnetic and the strongly magnetic iron sulphide is of the order of 400-500 m{sup 2} g{sup -1} as revealed by the magnetic properties, neutron scattering and the adsorption of a number of heavy metals. After freeze-drying the surface area falls to between 18 and 19 m{sup 2} g{sup -1}. The initial inocula came from a semi-saline source and when fed with nutrient containing Fe{sup 2+} and Fe{sup 3+} produced a weakly magnetic iron sulphide (Watson et al., Minerals Eng. 8 (1995) 1097) and a few % of a more strongly magnetic material. Further work using a novel method (Keller-Besrest, Collin, J. Solid State Chem. 84 (1990) 211) produced a strongly magnetic iron sulphide material. EXAFS and XANES spectroscopy revealed (Keller-Besrest and Collin, 1990) that the weakly magnetic iron sulphide material had the Ni-As structure in which the Fe is tetrahedrally coordinated with the

  16. Antimicrobial effects of gold/copper sulphide (Gold/Copper monosulfide) core/shell nanoparticles on Bacillus anthracis spores and cells

    Science.gov (United States)

    Addae, Ebenezer

    Bacillus anthracis is a gram positive, rod shaped and spore forming bacteria. It causes anthrax, a deadly human and animal disease that can kill its victims in three days. The spores of B. anthracis can survive extreme environmental conditions for decades and germinate when exposed to proper conditions. Due to its potential as a bio-weapon, effective disinfectants that pose less harm to the environment and animals are urgently needed. Metal nanoparticles have the potential of killing microbial cells and spores. We present here the effect of Gold/Copper Sulphide core/shell (Au/CuS) nanoparticles on B. anthracis cells and spores. The results indicated that the continuous presence of 0.83 microM during the spore growth in nutrient medium completely inhibited spore outgrowth. Au/CuS nanoparticles at concentration of 4.15 μM completely inactivated B. anthracis cells (x 107) after 30 min of pre-treatment in any of the three buffers including water, PBS, and nutrient broth. However, the same and even higher concentrations of nanoparticles produce no significant spore (x 105) killing after 24 h of pre-treatment. SEM imaging, EDS analysis, and DNA extrusion experiments revealed that nanoparticles damaged the cell membrane causing DNA and cytosolic content efflux and eventually cell death. The study demonstrated the strong antimicrobial activity of Au/CuS nanoparticles to B. anthracis cells and revealed that Au/CuS NPs showed more effective inactivation effect against the cells than they did against the spores.

  17. Interactions between TiO2 nanoparticles and cadmium: consequences for uptake and ecotoxicity

    DEFF Research Database (Denmark)

    Hartmann, B.; Baun, Anders

    2011-01-01

    sedimentation, the sediments are expected to be a sink for nanoparticles. Both in the water phase and in sediments they will mix and interact with other environmental pollutants, including heavy metals. In this study the toxicity of cadmium to three relevant freshwater species, green algae Pseudokirchneriella...

  18. Triazine-modified magnetite nanoparticles as a novel sorbent for preconcentration of lead and cadmium ions

    International Nuclear Information System (INIS)

    We report on a new sorbent for preconcentration of cadmium and lead ions that is based on triazine-functionalized magnetite nanoparticles that were prepared by direct silylation of magnetic nanoparticles with 3-aminopropyltriethoxysilane-2,4-bis(3,5-dimethylpyrazol)-triazine. The sorbent was characterized by IR spectroscopy, X-ray powder diffraction, scanning electron microscopy, thermal and elemental analysis. The sorbent was applied to the preconcentration of lead and cadmium ions which then were quantified by FAAS. The effects of sample pH value, extraction time, of type, concentration and volume of eluent, and of elution time were optimized. The limits of detection are 0.7 ng mL−1 for Pb(II) ion and 0.01 ng mL−1 for Cd(II). The effects of potentially interfering ions often found in real samples on the recovery in the determination of cadmium and lead ions in real samples were also investigated. The accuracy of the method was confirmed by analyzing the certified reference materials NIST 1571 (orchard leaves) and NIST 1572 (citrus leaves). Finally, the method was successfully applied to the determination of cadmium and lead ions in some fruit samples. (author)

  19. Electron beam-induced formation of crystalline nanoparticle chains from amorphous cadmium hydroxide nanofibers.

    Science.gov (United States)

    Stoychev, Georgi V; Okhrimenko, Denis V; Appelhans, Dietmar; Voit, Brigitte

    2016-01-01

    Quantum dots (QDs) and especially quantum dot arrays have been attracting tremendous attention due to their potential applications in various high-tech devices, including QD lasers, solar cells, single photon emitters, QD memories, etc. Here, a dendrimer-based approach for the controlled synthesis of ultra-thin amorphous cadmium hydroxide nanofibers was developed. The fragmentation of the obtained nanofibers in crystalline nanoparticle chains under the irradiation with electron beam was observed in both ambient and cryo-conditions. Based on the experimental results, a model for the formation of amorphous nanofibers, as well as their transformation in crystalline nanoparticle chains is proposed. We foresee that these properties of the nanofibers, combined with the possibility to convert cadmium hydroxide into CdX (X=O, S, Se, Te), could result in a new method for the preparation of 2D and 3D QDs-arrays with numerous potential applications in high performance devices. PMID:26397918

  20. Comparison of antibacterial activities of cadmium oxide nanoparticles against Pseudomonas Aeruginosa and Staphylococcus Aureus bacteria

    OpenAIRE

    Bahareh Salehi; Esmaeil Mortaz; Payam Tabarsi

    2015-01-01

    Background: Inorganic antibacterial factors have bacterial resistance and high thermal stability. Inorganic nanomaterials which have new structures with biological, chemical and physical properties have been made since their applications due to their nano size. In this study, the antibacterial effect of cadmium oxide nanoparticles on Staphylococcus aureus and Pseudomonas aeruginosa bacteria was investigated. Materials and Methods: The different concentrations (10 μg/ml, 15 μg/ml and 20 μg...

  1. Investigation of antibacterial effect of Cadmium Oxide nanoparticles on Staphylococcus Aureus bacteria

    OpenAIRE

    Salehi, Bahareh; Mehrabian, Sedigheh; Ahmadi, Mehdi

    2014-01-01

    Background Inorganic antibacterial factors provide high bacterial resistance and thermal stability. Inorganic nanomaterial consists of modern formulation, biological, chemical, and physical properties produced on the basis of their function and influenced by their nano scales, the reason for which they have become very popular. The antibacterial effect of Cadmium Oxide Nanoparticles on Staphylococcus Aureus has been studied for the first time in this research because of their resistance to an...

  2. Mitochondrial Toxicity of Cadmium Telluride Quantum Dot Nanoparticles in Mammalian Hepatocytes

    OpenAIRE

    Nguyen, Kathy C; Rippstein, Peter; Tayabali, Azam F.; Willmore, William G.

    2015-01-01

    There are an increasing number of studies indicating that mitochondria are relevant targets in nanomaterial-induced toxicity. However, the underlying mechanisms by which nanoparticles (NPs) interact with these organelles and affect their functions are unknown. The aim of this study was to investigate the effects of cadmium telluride quantum dot (CdTe-QD) NPs on mitochondria in human hepatocellular carcinoma HepG2 cells. CdTe-QD treatment resulted in the enlargement of mitochondria as examined...

  3. EXAFS and DFT study of the cadmium and lead adsorption on modified silica nanoparticles.

    Science.gov (United States)

    Arce, Valeria B; Gargarello, Romina M; Ortega, Florencia; Romañano, Virginia; Mizrahi, Martín; Ramallo-López, José M; Cobos, Carlos J; Airoldi, Claudio; Bernardelli, Cecilia; Donati, Edgardo R; Mártire, Daniel O

    2015-12-01

    Silica nanoparticles of 7 nm diameter were modified with (3-aminopropyl) triethoxysilane (APTES) and characterized by CP-MAS (13)C and (29)Si NMR, FTIR, zeta potential measurements, and thermogravimetry. The particles were shown to sorb successfully divalent lead and cadmium ions from aqueous solution. Lead complexation with these silica nanoparticles was clearly confirmed by EXAFS (Extended X-ray Absorption Fine Structure) with synchrotron light measurements. Predicted Pb-N and Pb-C distances obtained from quantum-chemical calculations are in very good agreement with the EXAFS determinations. The calculations also support the higher APTES affinity for Pb(2+) compared to Cd(2+). PMID:26135536

  4. Synthesis of Tunable Band Gap Semiconductor Nickel Sulphide Nanoparticles: Rapid and Round the Clock Degradation of Organic Dyes

    Science.gov (United States)

    Molla, Aniruddha; Sahu, Meenakshi; Hussain, Sahid

    2016-01-01

    Controlled shape and size with tuneable band gap (1.92–2.41 eV), nickel sulphide NPs was achieved in presence of thiourea or thioacetamide as sulphur sources with the variations of temperature and capping agents. Synthesized NPs were fully characterized by powder XRD, IR, UV-vis, DRS, FE-SEM, TEM, EDX, XPS, TGA and BET. Capping agent, temperature and sulphur sources have significant role in controlling the band gaps, morphology and surface area of NPs. The catalytic activities of NPs were tested for round the clock (light and dark) decomposition of crystal violet (CV), rhodamine B (RhB), methylene blue (MB), nile blue (NB) and eriochrome black T (EBT). Agitation speed, temperature, pH and ionic strength have significant role on its catalytic activities. The catalyst was found to generate reactive oxygen species (ROS) both in presence and absence of light which is responsible for the decomposition of dyes into small fractions, identified with ESI-mass spectra. PMID:27185051

  5. Synthesis of Tunable Band Gap Semiconductor Nickel Sulphide Nanoparticles: Rapid and Round the Clock Degradation of Organic Dyes

    Science.gov (United States)

    Molla, Aniruddha; Sahu, Meenakshi; Hussain, Sahid

    2016-05-01

    Controlled shape and size with tuneable band gap (1.92-2.41 eV), nickel sulphide NPs was achieved in presence of thiourea or thioacetamide as sulphur sources with the variations of temperature and capping agents. Synthesized NPs were fully characterized by powder XRD, IR, UV-vis, DRS, FE-SEM, TEM, EDX, XPS, TGA and BET. Capping agent, temperature and sulphur sources have significant role in controlling the band gaps, morphology and surface area of NPs. The catalytic activities of NPs were tested for round the clock (light and dark) decomposition of crystal violet (CV), rhodamine B (RhB), methylene blue (MB), nile blue (NB) and eriochrome black T (EBT). Agitation speed, temperature, pH and ionic strength have significant role on its catalytic activities. The catalyst was found to generate reactive oxygen species (ROS) both in presence and absence of light which is responsible for the decomposition of dyes into small fractions, identified with ESI-mass spectra.

  6. Novel fluorescent silver nanoparticles: sensitive and selective turn off sensor for cadmium ions

    Science.gov (United States)

    Makwana, Bharat A.; Vyas, Disha J.; Bhatt, Keyur D.; Darji, Savan; Jain, Vinod K.

    2016-04-01

    The synthesis of metal nanoparticles by eco-friendly and reliable processes is an important aspect in many fields. In this study, octamethoxy resorcin [4] arene tetrahydrazide (OMRTH)-reduced and stabilized silver nanoparticles were synthesized via a simple one-pot method. Synthesized silver nanoparticles were characterized by UV-visible spectroscopy, transmission electron microscopy (TEM) and particle size analyzer (PSA). Furthermore, the application of OMRTH-AgNps as a simple, cost-effective and sensitive fluorescent sensor for rapid detection of cadmium was explored. Under optimum conditions, the fluorescence intensity of OMRTH-AgNps was inversely proportional to the cadmium concentration. Using OMRTH-AgNps as a selective and sensitive fluorescent probe, cadmium can be detected at a minimum concentration level of 10-8 M in a facile way of fluorescence quenching, i.e., by a "turn off" mechanism. The method has been successfully applied for determination of Cd[II] ions in groundwater and industrial effluent wastewater samples.

  7. Inhaled Cadmium Oxide Nanoparticles: Their in Vivo Fate and Effect on Target Organs

    Science.gov (United States)

    Dumkova, Jana; Vrlikova, Lucie; Vecera, Zbynek; Putnova, Barbora; Docekal, Bohumil; Mikuska, Pavel; Fictum, Petr; Hampl, Ales; Buchtova, Marcela

    2016-01-01

    The increasing amount of heavy metals used in manufacturing equivalently increases hazards of environmental pollution by industrial products such as cadmium oxide (CdO) nanoparticles. Here, we aimed to unravel the CdO nanoparticle destiny upon their entry into lungs by inhalations, with the main focus on the ultrastructural changes that the nanoparticles may cause to tissues of the primary and secondary target organs. We indeed found the CdO nanoparticles to be transported from the lungs into secondary target organs by blood. In lungs, inhaled CdO nanoparticles caused significant alterations in parenchyma tissue including hyperemia, enlarged pulmonary septa, congested capillaries, alveolar emphysema and small areas of atelectasis. Nanoparticles were observed in the cytoplasm of cells lining bronchioles, in the alveolar spaces as well as inside the membranous pneumocytes and in phagosomes of lung macrophages. Nanoparticles even penetrated through the membrane into some organelles including mitochondria and they also accumulated in the cytoplasmic vesicles. In livers, inhalation caused periportal inflammation and local hepatic necrosis. Only minor changes such as diffusely thickened filtration membrane with intramembranous electron dense deposits were observed in kidney. Taken together, inhaled CdO nanoparticles not only accumulated in lungs but they were also transported to other organs causing serious damage at tissue as well as cellular level. PMID:27271611

  8. Inhaled Cadmium Oxide Nanoparticles: Their in Vivo Fate and Effect on Target Organs

    Directory of Open Access Journals (Sweden)

    Jana Dumkova

    2016-06-01

    Full Text Available The increasing amount of heavy metals used in manufacturing equivalently increases hazards of environmental pollution by industrial products such as cadmium oxide (CdO nanoparticles. Here, we aimed to unravel the CdO nanoparticle destiny upon their entry into lungs by inhalations, with the main focus on the ultrastructural changes that the nanoparticles may cause to tissues of the primary and secondary target organs. We indeed found the CdO nanoparticles to be transported from the lungs into secondary target organs by blood. In lungs, inhaled CdO nanoparticles caused significant alterations in parenchyma tissue including hyperemia, enlarged pulmonary septa, congested capillaries, alveolar emphysema and small areas of atelectasis. Nanoparticles were observed in the cytoplasm of cells lining bronchioles, in the alveolar spaces as well as inside the membranous pneumocytes and in phagosomes of lung macrophages. Nanoparticles even penetrated through the membrane into some organelles including mitochondria and they also accumulated in the cytoplasmic vesicles. In livers, inhalation caused periportal inflammation and local hepatic necrosis. Only minor changes such as diffusely thickened filtration membrane with intramembranous electron dense deposits were observed in kidney. Taken together, inhaled CdO nanoparticles not only accumulated in lungs but they were also transported to other organs causing serious damage at tissue as well as cellular level.

  9. Inhaled Cadmium Oxide Nanoparticles: Their in Vivo Fate and Effect on Target Organs.

    Science.gov (United States)

    Dumkova, Jana; Vrlikova, Lucie; Vecera, Zbynek; Putnova, Barbora; Docekal, Bohumil; Mikuska, Pavel; Fictum, Petr; Hampl, Ales; Buchtova, Marcela

    2016-01-01

    The increasing amount of heavy metals used in manufacturing equivalently increases hazards of environmental pollution by industrial products such as cadmium oxide (CdO) nanoparticles. Here, we aimed to unravel the CdO nanoparticle destiny upon their entry into lungs by inhalations, with the main focus on the ultrastructural changes that the nanoparticles may cause to tissues of the primary and secondary target organs. We indeed found the CdO nanoparticles to be transported from the lungs into secondary target organs by blood. In lungs, inhaled CdO nanoparticles caused significant alterations in parenchyma tissue including hyperemia, enlarged pulmonary septa, congested capillaries, alveolar emphysema and small areas of atelectasis. Nanoparticles were observed in the cytoplasm of cells lining bronchioles, in the alveolar spaces as well as inside the membranous pneumocytes and in phagosomes of lung macrophages. Nanoparticles even penetrated through the membrane into some organelles including mitochondria and they also accumulated in the cytoplasmic vesicles. In livers, inhalation caused periportal inflammation and local hepatic necrosis. Only minor changes such as diffusely thickened filtration membrane with intramembranous electron dense deposits were observed in kidney. Taken together, inhaled CdO nanoparticles not only accumulated in lungs but they were also transported to other organs causing serious damage at tissue as well as cellular level. PMID:27271611

  10. Gene expression profiling in rat kidney after intratracheal exposure to cadmium-doped nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Coccini, Teresa, E-mail: teresa.coccini@fsm.it; Roda, Elisa [University of Pavia, European Centre for Nanomedicine (Italy); Fabbri, Marco; Sacco, Maria Grazia; Gribaldo, Laura [European Commission Institute for Health and Consumer Protection (IHCP), JRC (Italy); Manzo, Luigi [University of Pavia, European Centre for Nanomedicine (Italy)

    2012-08-15

    While nephrotoxicity of cadmium is well documented, very limited information exists on renal effects of exposure to cadmium-containing nanomaterials. In this work, 'omics' methodologies have been used to assess the action of cadmium-containing silica nanoparticles (Cd-SiNPs) in the kidney of Sprague-Dawley rats exposed intratracheally. Groups of animals received a single dose of Cd-SiNPs (1 mg/rat), CdCl{sub 2} (400 {mu}g/rat) or 0.1 ml saline (control). Renal gene expression was evaluated 7 and 30 days post exposure by DNA microarray technology using the Agilent Whole Rat Genome Microarray 4x44K. Gene modulating effects were observed in kidney at both time periods after treatment with Cd-SiNPs. The number of differentially expressed genes being 139 and 153 at the post exposure days 7 and 30, respectively. Renal gene expression changes were also observed in the kidney of CdCl{sub 2}-treated rats with a total of 253 and 70 probes modulated at 7 and 30 days, respectively. Analysis of renal gene expression profiles at day 7 indicated in both Cd-SiNP and CdCl{sub 2} groups downregulation of several cluster genes linked to immune function, oxidative stress, and inflammation processes. Differing from day 7, the majority of cluster gene categories modified by nanoparticles in kidney 30 days after dosing were genes implicated in cell regulation and apoptosis. Modest renal gene expression changes were observed at day 30 in rats treated with CdCl{sub 2}. These results indicate that kidney may be a susceptible target for subtle long-lasting molecular alterations produced by cadmium nanoparticles locally instilled in the lung.

  11. The potential of TiO{sub 2} nanoparticles as carriers for cadmium uptake in Lumbriculus variegatus and Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Nanna B., E-mail: Nanna.Hartmann@ec.europa.eu [Department of Environmental Engineering, Technical University of Denmark, Building 113, Kgs. Lyngby (Denmark); Legros, Samuel; Von der Kammer, Frank; Hofmann, Thilo [Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, A-1090 Vienna (Austria); Baun, Anders [Department of Environmental Engineering, Technical University of Denmark, Building 113, Kgs. Lyngby (Denmark)

    2012-08-15

    The use of engineered nanoparticles (e.g. in industrial applications and consumer products) is increasing. Consequently, these particles will be released into the aquatic environment. Through aggregation/agglomeration and sedimentation, sediments are expected ultimately to be sinks for nanoparticles. Both in the water phase and in the sediments engineered nanoparticles will mix and interact with other environmental pollutants, including metals. In this study the toxicity of cadmium to two freshwater organisms, water column crustacean Daphnia magna and sediment oligochaete Lumbriculus variegatus, was investigated both in the absence and presence of titanium dioxide (TiO{sub 2}) nanoparticles (P25 Evonic Degussa, d: 30 nm). The uptake of cadmium in sub-lethal concentrations was also studied in the absence and presence of 2 mg/L TiO{sub 2} nanoparticles. Formation of larger nanoparticles aggregates/agglomerates was observed and sizes varied depending on media composition (358 {+-} 13 nm in US EPA moderately hard synthetic freshwater and 1218 {+-} 7 nm in Elendt M7). TiO{sub 2} nanoparticles are potential carriers for cadmium and it was found that 25% and 6% of the total cadmium mass in the test system for L. variegatus and D. magna tests were associated to suspended TiO{sub 2} particles, respectively. {mu}XRF (micro X-ray fluorescence) analysis confirmed the uptake of TiO{sub 2} in the gut of D. magna. For L. variegatus {mu}XRF analysis indicated attachment of TiO{sub 2} nanoparticles to the organism surface as well as a discrete distribution within the organisms. Though exact localisation in this organism was more difficult to assess, the uptake seems to be within the coelomic cavity. Results show that the overall body burden and toxicity of cadmium to L. variegatus was unchanged by addition of TiO{sub 2} nanoparticles, showing that cadmium adsorption to TiO{sub 2} nanoparticles did not affect overall bioavailability. Despite facilitated uptake of cadmium by Ti

  12. Impact of carboxymethyl cellulose coating on iron sulphide nanoparticles stability, transport, and mobilization potential of trace metals present in soils and sediment.

    Science.gov (United States)

    Van Koetsem, Frederik; Van Havere, Lynn; Du Laing, Gijs

    2016-03-01

    The stability and transport behaviour of carboxymethyl cellulose (CMC) stabilized iron sulphide (FeS) engineered nanoparticles (ENPs) as well as their concurrent scavenging and mobilization of trace metal contaminants from field-contaminated soils and sediment was studied through a series of batch and column experiments. The synthesized CMC-FeS ENPs were shown to have a hydrodynamic diameter of 154.5 ± 5.8 nm and remained stable in suspension for a prolonged period of time (several weeks) when kept under anaerobic conditions. In the absence of CMC, much larger FeS particles were formed, which quickly aggregated and precipitated within minutes. Batch experiments indicated that the CMC-FeS ENPs have a high affinity for metal contaminants (e.g., Cd, Cr, Cu, Hg, Ni, Pb, and Zn), as high amounts of these trace metals could be retrieved in the aqueous phase after treatment of the soils with the nanoparticles (i.e., up to 29 times more compared to the water-leachable metal contents). Furthermore, batch retention of the nanoparticles by the solid soil phase was low (Nanoparticle treatment of the soils also affected the CaCl2-, TCLP-, and SPLP-leachability of trace metals, although no clear trend could be observed and metal leaching appeared to depend on the specific element under consideration, the type of extraction liquid, as well as on soil properties. Column breakthrough tests demonstrated that the CMC-FeS ENPs were highly mobile in the tested soil, even without the use of an external pressure (i.e., just via gravitational percolation). Maximal breakthrough of the nanoparticles was observed after approximately 10 or 16 pore volumes (PVs) for 83.3 or 500 mg L(-1) CMC-FeS ENPs, respectively, and only about 7% of the nanoparticles were retained by the soil after 22.7 PVs. Simultaneous elution of trace elements showed that up to 19, 8.7, or 11% of the respective Cd, Pb, or Zn content originally present in the soil was extracted after 22.7 PVs, with initial peaking

  13. Development of Novel Cadmium-Free AgInS2 Semiconductor Nanoparticles.

    Science.gov (United States)

    Yang, Wentao; Gong, Xiaoqun; Chang, Jin

    2016-03-01

    AgInS2 (AIS) semiconductor nanoparticles as the novel alternatives to cadmium- or lead-containing semiconductors have attracted much attention both on the theory and application research, based on their tunable fluorescence emission wavelengths, high photostability and low toxicity of chemical composition. The bandgap of AIS nanoparticles can be adjusted from 1.54 to 2.03 eV, which makes AIS nanocrystalline suitable for applications in solar energy conversion. Moreover, the fluorescence emission wavelengths can be tuned in the near-infrared regions, and thus make it the next-generation low-toxicity materials for the applications in bioimaging. In this review, the research progress of the AIS nanoparticles is summarized, including synthetic methods, properties and the possibilities to influence their shape and crystallographic structure. Furthermore, we discuss the potential applications of this novel material in photocatalysis, solar energy conversion and biological area. PMID:27455616

  14. The Potential Application of Raw Cadmium Sulfide Nanoparticles as CT Photographic Developer.

    Science.gov (United States)

    Wu, Qiang; Huang, Lingxin; Li, Zhan; An, Wenzhen; Liu, Dan; Lin, Jin; Tian, Longlong; Wang, Xinling; Liu, Bo; Qi, Wei; Wu, Wangsuo

    2016-12-01

    With the development of science and technology, new applications about nanoparticles should be explored to achieve full-scale knowledge. Therefore, in this work, the toxicity and potential application of raw cadmium sulfide nanoparticles (CdS) in vivo were further studied through ICP-OES and CTs. Surprisingly, CdS exhibited an excellent photographic property, except for finding the accumulation of CdS in the lungs, liver, spleen, and kidney with a strong dependence on time; it is also found that there were a significant uptake in the pancreas for an obvious CT imaging. And the following investigations showed that the raw CdS could damage the tissues accumulating nanoparticles. Through this work, it can be seen that the raw CdS being modified might be an excellent photographic developer for detecting cancers or other diseases.

  15. The Potential Application of Raw Cadmium Sulfide Nanoparticles as CT Photographic Developer.

    Science.gov (United States)

    Wu, Qiang; Huang, Lingxin; Li, Zhan; An, Wenzhen; Liu, Dan; Lin, Jin; Tian, Longlong; Wang, Xinling; Liu, Bo; Qi, Wei; Wu, Wangsuo

    2016-12-01

    With the development of science and technology, new applications about nanoparticles should be explored to achieve full-scale knowledge. Therefore, in this work, the toxicity and potential application of raw cadmium sulfide nanoparticles (CdS) in vivo were further studied through ICP-OES and CTs. Surprisingly, CdS exhibited an excellent photographic property, except for finding the accumulation of CdS in the lungs, liver, spleen, and kidney with a strong dependence on time; it is also found that there were a significant uptake in the pancreas for an obvious CT imaging. And the following investigations showed that the raw CdS could damage the tissues accumulating nanoparticles. Through this work, it can be seen that the raw CdS being modified might be an excellent photographic developer for detecting cancers or other diseases. PMID:27121440

  16. The Potential Application of Raw Cadmium Sulfide Nanoparticles as CT Photographic Developer

    Science.gov (United States)

    Wu, Qiang; Huang, Lingxin; Li, Zhan; An, Wenzhen; Liu, Dan; Lin, Jin; Tian, Longlong; Wang, Xinling; Liu, Bo; Qi, Wei; Wu, Wangsuo

    2016-04-01

    With the development of science and technology, new applications about nanoparticles should be explored to achieve full-scale knowledge. Therefore, in this work, the toxicity and potential application of raw cadmium sulfide nanoparticles (CdS) in vivo were further studied through ICP-OES and CTs. Surprisingly, CdS exhibited an excellent photographic property, except for finding the accumulation of CdS in the lungs, liver, spleen, and kidney with a strong dependence on time; it is also found that there were a significant uptake in the pancreas for an obvious CT imaging. And the following investigations showed that the raw CdS could damage the tissues accumulating nanoparticles. Through this work, it can be seen that the raw CdS being modified might be an excellent photographic developer for detecting cancers or other diseases.

  17. Development of Novel Cadmium-Free AgInS2 Semiconductor Nanoparticles.

    Science.gov (United States)

    Yang, Wentao; Gong, Xiaoqun; Chang, Jin

    2016-03-01

    AgInS2 (AIS) semiconductor nanoparticles as the novel alternatives to cadmium- or lead-containing semiconductors have attracted much attention both on the theory and application research, based on their tunable fluorescence emission wavelengths, high photostability and low toxicity of chemical composition. The bandgap of AIS nanoparticles can be adjusted from 1.54 to 2.03 eV, which makes AIS nanocrystalline suitable for applications in solar energy conversion. Moreover, the fluorescence emission wavelengths can be tuned in the near-infrared regions, and thus make it the next-generation low-toxicity materials for the applications in bioimaging. In this review, the research progress of the AIS nanoparticles is summarized, including synthetic methods, properties and the possibilities to influence their shape and crystallographic structure. Furthermore, we discuss the potential applications of this novel material in photocatalysis, solar energy conversion and biological area.

  18. The Impact of Polyvinylpyrrolidone on Properties of Cadmium Oxide Semiconductor Nanoparticles Manufactured by Heat Treatment Technique

    Directory of Open Access Journals (Sweden)

    Naif Mohammed Al-Hada

    2016-04-01

    Full Text Available Cadmium oxide semiconductor nanoparticles were produced using a water based mixture, incorporating cadmium nitrates, polyvinyl pyrrolidone (PVP, and calcination temperature. An X-ray diffraction (XRD evaluation was conducted to determine the degree of crystallization of the semiconductor nanoparticles. In addition, scanning electron microscopy (SEM was conducted to identify the morphological features of the nanoparticles. The typical particle sizes and particle dispersal were analyzed via the use of transmission electron microscopy (TEM. The findings provided further support for the XRD outcomes. To determine the composition phase, Fourier transform infrared spectroscopy (FT-IR was conducted, as it indicated the existence of not only metal oxide ionic band in the selection of samples, but also the efficient removal of organic compounds following calcinations. The optical characteristics were demonstrated, so as to analyze the energy band gap via the use of a UV–Vis spectrophotometer. A reduced particle size resulted in diminution of the intensity of photoluminescence, was demonstrated by PL spectra. Plus, the magnetic characteristics were examined using an electron spin resonance (ESR spectroscopy, which affirmed the existence of unpaired electrons.

  19. Synthesis, characterization, and electrical properties studies of cadmium selenide nanoparticle

    Science.gov (United States)

    Seoudi, R.; Elokr, M. M.; Shabaka, A. A.; Sobhi, A.

    2008-01-01

    A new solvothermal route was used for the preparation of CdSe nanoparticles at 160 °C for 10 h using ethylenediamine as a solvent. X-ray powder diffraction and transmission electron microscope were employed to characterize the size, morphology, and crystalline structure of the as-prepared sample. The formation process was discussed and it revealed a uniform hexagonal shape of CdSe nanoparticle with good dispersion, with an average size of 35 nm. Fourier transform infrared and ultraviolet-visible spectroscopies were used to follow the reaction and to determine the optical band gap. DC and AC electrical conductivities were studied and the activation energies were determined as well as the conduction mechanism. The results indicated that CdSe behaves as a semiconducting material. The dielectric properties were measured as a function of temperature at different frequencies ranging from 100 Hz to 100 kHz. The increase of the dielectric constant with increasing temperature was discussed on the basis of increasing polarizability, while its decrease with increasing frequency is attributed to the dielectric dispersion.

  20. Synthesis, characterization, and electrical properties studies of cadmium selenide nanoparticle

    International Nuclear Information System (INIS)

    A new solvothermal route was used for the preparation of CdSe nanoparticles at 160 deg. C for 10 h using ethylenediamine as a solvent. X-ray powder diffraction and transmission electron microscope were employed to characterize the size, morphology, and crystalline structure of the as-prepared sample. The formation process was discussed and it revealed a uniform hexagonal shape of CdSe nanoparticle with good dispersion, with an average size of 35 nm. Fourier transform infrared and ultraviolet-visible spectroscopies were used to follow the reaction and to determine the optical band gap. DC and AC electrical conductivities were studied and the activation energies were determined as well as the conduction mechanism. The results indicated that CdSe behaves as a semiconducting material. The dielectric properties were measured as a function of temperature at different frequencies ranging from 100 Hz to 100 kHz. The increase of the dielectric constant with increasing temperature was discussed on the basis of increasing polarizability, while its decrease with increasing frequency is attributed to the dielectric dispersion

  1. Manufacturing and Morphological Analysis of Composite Material of Polystyrene Nanospheres/Cadmium Metal Nanoparticles

    Directory of Open Access Journals (Sweden)

    Pratama Jujur Wibawa

    2013-03-01

    Full Text Available A very simple nanocomposite material has been in-situ manufactured from an aqueous polystyrene nanospheres dispersion and cadmium (Cd metal nanoparticles. The manufacturing was performed by using a high frequency of 40 kHz ultrasonic (US agitation for 45 minute at atmospheric pressure and at room temperature 20 oC. No chemical reducing agent and surfactant added in this manufacturing technique due to the US could reduce Cd2+ ions of cadmium nitrate tetrahydrate to Cd atomic metals nanoparticles whereas water molecules could act as a pseudo stabilizer for the manufactured material. A thin film was manufactured from aqueous colloidal nanocomposite material of Polystyrene nanospheres/Cd metal nanoparticles (PSNs/CdMNp fabricated on a hydrophilic silicon wafer. The thin film was then characterized by a JEOL-FESEM for its surface morphology characteristic and by ATR-FTIR spectrometry for its molecular change investigation. It could be clearly observed that surface morphology of the thin film material was not significantly changed under 633 nm wavelength continuous laser radiation exposure for 20 minute. In addition, its ATR-FTIR spectra of wave number peaks around 3400 cm-1 have been totally disappeared under the laser exposure whereas that at around 699 cm-1 and 668 cm-1 have not been significantly changed. The first phenomenon indicated that the hydrogen bond existed in PSNs/CdMNp material was collapsed by the laser exposure. The second phenomena indicated that the PSNs phenyl ring moiety was not totally destroyed under the laser exposure. It was suspected due to the existence of Cd nanoparticles covered throughout the spherical surface of PSNs/CdMNp material particles. Therefore a nice model of material structure of the mentioned PSNs/CdMNp nanocomposite material could be suggested in this research. It could be concluded that this research have been performed since the material structure model of the manufactured PSNs/CdMNp nanocomposite could be

  2. Biocatalytic etching of semiconductor cadmium sulfide nanoparticles as a new platform for the optical detection of analytes.

    Science.gov (United States)

    Grinyte, R; Saa, L; Garai-Ibabe, G; Pavlov, V

    2015-12-14

    We report for the first time the enzymatic etching of cadmium sulfide nanoparticles (CdS NPs). The fluorescence of semiconductor CdS NPs is modulated irreversibly by an enzymatic reaction catalyzed by horseradish peroxidase (HRP). We observed blue-shifts of the corresponding fluorescence peaks for CdS NPs and a decrease in the intensity of the fluorescence signal.

  3. The potential of TiO2 nanoparticles as carriers for cadmium uptake in Lumbriculus variegatus and Daphnia magna

    DEFF Research Database (Denmark)

    Hartmann, Nanna Isabella Bloch; Legros, Samuel; Von der Kammer, Frank;

    2012-01-01

    variegatus, was investigated both in the absence and presence of titanium dioxide (TiO2) nanoparticles (P25 Evonic Degussa, d: 30nm). The uptake of cadmium in sub-lethal concentrations was also studied in the absence and presence of 2mg/L TiO2 nanoparticles. Formation of larger nanoparticles aggregates...

  4. Revealing a room temperature ferromagnetism in cadmium oxide nanoparticles: An experimental and first-principles study

    KAUST Repository

    Bououdina, Mohamed

    2015-03-26

    We obtain a single cadmium oxide phase from powder synthesized by a thermal decomposition method of cadmium acetate dehydrate. The yielded powder is annealed in air, vacuum, and H2 gas in order to create point defects. Magnetization-field curves reveal the appearance of diamagnetic behavior with a ferromagnetic component for all the powders. Powder annealing under vacuum and H2 atmosphere leads to a saturation magnetization 1.15 memu g-1 and 1.2 memu g-1 respectively with an increase by 45% and 16% compared to the one annealed in air. We show that annealing in vacuum produces mainly oxygen vacancies while annealing in H2 gas creates mainly Cd vacancy leading to room temperature ferromagnetic (RTFM) component together with known diamagnetic properties. Ab initio calculations performed on the CdO nanoparticles show that the magnetism is governed by polarized hybrid states of the Cd d and O p orbitals together with the vacancy. © The Royal Society of Chemistry 2015.

  5. Gene expression analysis in rat lungs after intratracheal exposure to nanoparticles doped with cadmium

    Science.gov (United States)

    Coccini, Teresa; Fabbri, Marco; Roda, Elisa; Grazia Sacco, Maria; Manzo, Luigi; Gribaldo, Laura

    2011-07-01

    Silica nanoparticles (NPs) incorporating cadmium (Cd) have been developed for a range of potential application including drug delivery devices. Occupational Cd inhalation has been associated with emphysema, pulmonary fibrosis and lung tumours. Mechanistically, Cd can induce oxidative stress and mediate cell-signalling pathways that are involved in inflammation.This in vivo study aimed at investigating pulmonary molecular effects of NPs doped with Cd (NP-Cd, 1 mg/animal) compared to soluble CdCl2 (400 μg/animal), in Sprague Dawley rats treated intra-tracheally, 7 and 30 days after administration. NPs of silica containing Cd salt were prepared starting from commercial nano-size silica powder (HiSil™ T700 Degussa) with average pore size of 20 nm and surface area of 240 m2/g. Toxicogenomic analysis was performed by the DNA microarray technology (using Agilent Whole Rat Genome Microarray 4×44K) to evaluate changes in gene expression of the entire genome. These findings indicate that the whole genome analysis may represent a valuable approach to assess the whole spectrum of biological responses to cadmium containing nanomaterials.

  6. Gene expression analysis in rat lungs after intratracheal exposure to nanoparticles doped with cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Coccini, Teresa; Manzo, Luigi [Toxicology Division, Salvatore Maugeri Foundation IRCCS, Pavia (Italy); Fabbri, Marco; Sacco, Maria Grazia; Gribaldo, Laura [European Commission, Joint Research Centre, IHCP- 21027 Ispra (Italy); Roda, Elisa [European Centre for Nanomedicine, University of Pavia, 27100 Pavia (Italy)

    2011-07-06

    Silica nanoparticles (NPs) incorporating cadmium (Cd) have been developed for a range of potential application including drug delivery devices. Occupational Cd inhalation has been associated with emphysema, pulmonary fibrosis and lung tumours. Mechanistically, Cd can induce oxidative stress and mediate cell-signalling pathways that are involved in inflammation.This in vivo study aimed at investigating pulmonary molecular effects of NPs doped with Cd (NP-Cd, 1 mg/animal) compared to soluble CdCl{sub 2} (400 {mu}g/animal), in Sprague Dawley rats treated intra-tracheally, 7 and 30 days after administration. NPs of silica containing Cd salt were prepared starting from commercial nano-size silica powder (HiSil{sup TM} T700 Degussa) with average pore size of 20 nm and surface area of 240 m{sup 2}/g. Toxicogenomic analysis was performed by the DNA microarray technology (using Agilent Whole Rat Genome Microarray 4x44K) to evaluate changes in gene expression of the entire genome. These findings indicate that the whole genome analysis may represent a valuable approach to assess the whole spectrum of biological responses to cadmium containing nanomaterials.

  7. Colorimetric Detection of Cadmium Ions Using DL-Mercaptosuccinic Acid-Modified Gold Nanoparticles.

    Science.gov (United States)

    Chen, Na; Chen, Jun; Yang, Jing-Hua; Bai, Lian-Yang; Zhang, Yu-Ping

    2016-01-01

    A colorimetric assay has been developed for detection of Cd²⁺ utilizing DL-mercaptosuccinic acid-modified gold nanoparticles (MSA-AuNPs). The method showed good selectivity for Cd²⁺ over other metal ions. As a result, the linear relationships (r > 0.9606) between concentration 0.07 mM and 0.20 mM for cadmium ion were obtained. The detection limit was as low as 0.07 mM by the naked eye. The effect of pH on the aggregation was optimized. The MSA-AuNPs probe could be used to detect Cd²⁺ in an aqueous solution based on the aggregation-induced color change of MSA-AuNPs. PMID:27398533

  8. Cadmium Sulfide Nanoparticles Synthesized by Microwave Heating for Hybrid Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Claudia Martínez-Alonso

    2014-01-01

    Full Text Available Cadmium sulfide nanoparticles (CdS-n are excellent electron acceptor for hybrid solar cell applications. However, the particle size and properties of the CdS-n products depend largely on the synthesis methodologies. In this work, CdS-n were synthetized by microwave heating using thioacetamide (TA or thiourea (TU as sulfur sources. The obtained CdS-n(TA showed a random distribution of hexagonal particles and contained TA residues. The latter could originate the charge carrier recombination process and cause a low photovoltage (Voc, 0.3 V in the hybrid solar cells formed by the inorganic particles and poly(3-hexylthiophene (P3HT. Under similar synthesis conditions, in contrast, CdS-n synthesized with TU consisted of spherical particles with similar size and contained carbonyl groups at their surface. CdS-n(TU could be well dispersed in the nonpolar P3HT solution, leading to a Voc of about 0.6–0.8 V in the resulting CdS-n(TU : P3HT solar cells. The results of this work suggest that the reactant sources in microwave methods can affect the physicochemical properties of the obtained inorganic semiconductor nanoparticles, which finally influenced the photovoltaic performance of related hybrid solar cells.

  9. An amperometric chloramphenicol immunosensor based on cadmium sulfide nanoparticles modified-dendrimer bonded conducting polymer.

    Science.gov (United States)

    Kim, Dong-Min; Rahman, Md Aminur; Do, Minh Hien; Ban, Changill; Shim, Yoon-Bo

    2010-03-15

    An amperometric chloramphenicol (CAP) immunosensor was fabricated by covalently immobilizing anti-chloramphenicol acetyl transferase (anti-CAT) antibody on cadmium sulfide nanoparticles (CdS) modified-dendrimer that was bonded to the conducting polymer (poly 5, 2': 5', 2''-terthiophene-3'-carboxyl acid (poly-TTCA)) layer. The AuNPs, dendrimers, and CdS nanoparticles were deposited onto the polymer layer in order to enhance the sensitivity of the sensor probes. The particle sizes were determined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The immobilization of dendrimers, CdS, and anti-CAT were confirmed using energy disruptive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and quartz crystal microbalance (QCM) techniques. The detection of CAP was based on the competitive immuno-interaction between the free- and labeled-CAP for active sites of the anti-CAT. Hydrazine was used as the label for CAP, and it electrochemically catalyzed the reduction of H(2)O(2) at -0.35 V vs. Ag/AgCl. Under optimized conditions, the proposed immunosensor exhibited a linear range of CAP detection between 50 pg/mL and 950 pg/mL, and the detection limit was 45 pg/mL. The immunosensor was examined in real meat samples for the analysis of CAP.

  10. New barium tantalum sulphides

    International Nuclear Information System (INIS)

    The authors discuss a new barium tantalum sulphide, Ba3Ta2S8, prepared by sulphurization of a mixture of BaCO3 and Ta2O5. The electron and powder X-ray diffraction patterns of the compound are indexed on the basis of a monoclinic cell with lattice constants. A structure model is proposed. The refinement based on the powder X-ray diffraction intensities is performed

  11. Synthesis, characterization and toxicological evaluation of maltodextrin capped cadmium sulfide nanoparticles in human cell lines and chicken embryos

    Directory of Open Access Journals (Sweden)

    Rodríguez-Fragoso Patricia

    2012-12-01

    Full Text Available Abstract Background Semiconductor Quantum dots (QDs have become quite popular thanks to their properties and wide use in biological and biomedical studies. However, these same properties entail new challenges in understanding, predicting, and managing potential adverse health effects following exposure. Cadmium and selenium, which are the major components of the majority of quantum dots, are known to be acutely and chronically toxic to cells and organisms. Protecting the core of nanoparticles can, to some degree, control the toxicity related to cadmium and selenium leakage. Results This study successfully synthesized and characterized maltodextrin coated cadmium sulfide semiconductor nanoparticles. The results show that CdS-MD nanoparticles are cytotoxic and embryotoxic. CdS-MD nanoparticles in low concentrations (4.92 and 6.56 nM lightly increased the number of HepG2 cell. A reduction in MDA-MB-231 cells was observed with concentrations higher than 4.92 nM in a dose response manner, while Caco-2 cells showed an important increase starting at 1.64 nM. CdS-MD nanoparticles induced cell death by apoptosis and necrosis in MDA-MD-231 cells starting at 8.20 nM concentrations in a dose response manner. The exposure of these cells to 11.48-14.76 nM of CdS-MD nanoparticles induced ROS production. The analysis of cell proliferation in MDA-MB-231 showed different effects. Low concentrations (1.64 nM increased cell proliferation (6% at 7 days (p 4.92 nM increased cell proliferation in a dose response manner (15-30% at 7 days. Exposures of chicken embryos to CdS-MD nanoparticles resulted in a dose-dependent increase in anomalies that, starting at 9.84 nM, centered on the heart, central nervous system, placodes, neural tube and somites. No toxic alterations were observed with concentrations of  Conclusions Our results indicate that CdS-MD nanoparticles induce cell death and alter cell proliferation in human cell lines at concentrations higher than 4.92 n

  12. Loading of atorvastatin and linezolid in β-cyclodextrin-conjugated cadmium selenide/silica nanoparticles: A spectroscopic study.

    Science.gov (United States)

    Antony, Eva Janet; Shibu, Abhishek; Ramasamy, Sivaraj; Paulraj, Mosae Selvakumar; Enoch, Israel V M V

    2016-08-01

    The preparation of β-cyclodextrin-conjugated cadmium selenide-silica nanoparticles, the loading of two drugs viz., Atorvastatin and linezolid in the cyclodextrin cavity, and the fluorescence energy transfer between CdSe/SiO2 nanoparticles and the drugs encapsulated in the cyclodextrin cavity are reported in this paper. IR spectroscopy, X-ray diffractometry, transmission electron microscopy, and particle size analysis by light-scattering experiment were used as the tools of characterizing the size and the crystal system of the nanoparticles. The nanoparticles fall under hexagonal system. The silica-shell containing CdSe nanoparticles were functionalized by reaction with aminoethylamino-β-cyclodextrin. Fluorescence spectra of the nanoparticles in their free and drug-encapsulated forms were studied. The FÖrster distances between the encapsulated drugs and the CdSe nanoparticles are below 3nm. The change in the FÖrster resonance energy parameters under physiological conditions may aid in tracking the release of drugs from the cavity of the cyclodextrin. PMID:27157743

  13. Magnetite nanoparticle (NP) uptake by wheat plants and its effect on cadmium and chromium toxicological behavior.

    Science.gov (United States)

    López-Luna, J; Silva-Silva, M J; Martinez-Vargas, S; Mijangos-Ricardez, O F; González-Chávez, M C; Solís-Domínguez, F A; Cuevas-Díaz, M C

    2016-09-15

    The aim of this work was to assess the uptake of citrate-coated magnetite nanoparticles (NPs) by wheat plants and its effect on the bioaccumulation and toxicity of individual and joint Cd(2+) and Cr(6+) levels. Seven-day assays were conducted using quartz sand as the plant growth substrate. The endpoints measured were seed germination, root and shoot lengths, and heavy metal accumulation. Magnetite exhibited very low toxicity, regardless of the wheat seedling NP uptake and distribution into roots and shoots. The seed germination and shoot length were not sensitive enough, while the root length was a more sensitive toxicity endpoint. The root length of wheat seedlings exposed to individual metals decreased by 50% at 2.67mgCd(2)(+)kg(-1) and 5.53mgCr(6+)kg(-1). However, when magnetite NPs (1000mgkg(-1)) were added, the root length of the plants increased by 25 and 50%. Cd(2+) and Cr(6+) showed similar and noninteractive joint action, but strongly impaired the wheat seedlings. In contrast, an interactive infra-additive or antagonistic effect was observed upon adding magnetite NPs. Thus, cadmium and chromium accumulation in vegetable tissues was considerately diminished and the toxicity alleviated.

  14. Cadmium telluride nanoparticles loaded on activated carbon as adsorbent for removal of sunset yellow

    Science.gov (United States)

    Ghaedi, M.; Hekmati Jah, A.; Khodadoust, S.; Sahraei, R.; Daneshfar, A.; Mihandoost, A.; Purkait, M. K.

    2012-05-01

    Adsorption is a promising technique for decolorization of effluents of textile dyeing industries but its application is limited due to requirement of high amounts of adsorbent required. The objective of this study was to assess the potential of cadmium telluride nanoparticles loaded onto activated carbon (CdTN-AC) for the removal of sunset yellow (SY) dye from aqueous solution. Adsorption studies were conducted in a batch mode varying solution pH, contact time, initial dye concentration, CdTN-AC dose, and temperature. In order to investigate the efficiency of SY adsorption on CdTN-AC, pseudo-first-order, pseudo-second-order, Elovich, and intra-particle diffusion kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic models with good correlation coefficient. Equilibrium data were fitted to the Langmuir model. Thermodynamic parameters such as enthalpy, entropy, activation energy, and sticking probability were also calculated. It was found that the sorption of SY onto CdTN-AC was spontaneous and endothermic in nature. The proposed adsorbent is applicable for SY removal from waste of real effluents including pea-shooter, orange drink and jelly banana with efficiency more than 97%.

  15. Magnetite nanoparticle (NP) uptake by wheat plants and its effect on cadmium and chromium toxicological behavior.

    Science.gov (United States)

    López-Luna, J; Silva-Silva, M J; Martinez-Vargas, S; Mijangos-Ricardez, O F; González-Chávez, M C; Solís-Domínguez, F A; Cuevas-Díaz, M C

    2016-09-15

    The aim of this work was to assess the uptake of citrate-coated magnetite nanoparticles (NPs) by wheat plants and its effect on the bioaccumulation and toxicity of individual and joint Cd(2+) and Cr(6+) levels. Seven-day assays were conducted using quartz sand as the plant growth substrate. The endpoints measured were seed germination, root and shoot lengths, and heavy metal accumulation. Magnetite exhibited very low toxicity, regardless of the wheat seedling NP uptake and distribution into roots and shoots. The seed germination and shoot length were not sensitive enough, while the root length was a more sensitive toxicity endpoint. The root length of wheat seedlings exposed to individual metals decreased by 50% at 2.67mgCd(2)(+)kg(-1) and 5.53mgCr(6+)kg(-1). However, when magnetite NPs (1000mgkg(-1)) were added, the root length of the plants increased by 25 and 50%. Cd(2+) and Cr(6+) showed similar and noninteractive joint action, but strongly impaired the wheat seedlings. In contrast, an interactive infra-additive or antagonistic effect was observed upon adding magnetite NPs. Thus, cadmium and chromium accumulation in vegetable tissues was considerately diminished and the toxicity alleviated. PMID:26806072

  16. Titanium dioxide nanoparticles modulate the toxicological response to cadmium in the gills of Mytilus galloprovincialis.

    Science.gov (United States)

    Della Torre, Camilla; Balbi, Teresa; Grassi, Giacomo; Frenzilli, Giada; Bernardeschi, Margherita; Smerilli, Arianna; Guidi, Patrizia; Canesi, Laura; Nigro, Marco; Monaci, Fabrizio; Scarcelli, Vittoria; Rocco, Lucia; Focardi, Silvano; Monopoli, Marco; Corsi, Ilaria

    2015-10-30

    We investigated the influence of titanium dioxide nanoparticles (nano-TiO2) on the response to cadmium in the gills of the marine mussel Mytilus galloprovincialis in terms of accumulation and toxicity. Mussels were in vivo exposed to nano-TiO2, CdCl2, alone and in combination. Several cellular biomarkers were investigated in gills: ABC transport proteins and metallothioneins at gene/protein (abcb1, abcc-like and mt-20) and functional level, GST activity, NO production and DNA damage (Comet assay). Accumulation of total Cd and titanium in gills as in whole soft tissue was also investigated. Significant responses to Cd exposure were observed in mussel gills as up-regulation of abcb1 and mt-20 gene transcription, increases in total MT content, P-gp efflux and GST activity, DNA damage and NO production. Nano-TiO2 alone increased P-gp efflux activity and NO production. When combined with Cd, nano-TiO2 reduced the metal-induced effects by significantly lowering abcb1 gene transcription, GST activity, and DNA damage, whereas, additive effects were observed on NO production. A lower concentration of Cd was observed in the gills upon co-exposure, whereas, Ti levels were unaffected. A competitive effect in uptake/accumulation of nano-TiO2 and Cd seems to occur in gills. A confirmation is given by the observed absence of adsorption of Cd onto nano-TiO2 in sea water media.

  17. Different behavior of Staphylococcus epidermidis in intracellular biosynthesis of silver and cadmium sulfide nanoparticles: more stability and lower toxicity of extracted nanoparticles.

    Science.gov (United States)

    Rezvani Amin, Zohreh; Khashyarmanesh, Zahra; Fazly Bazzaz, Bibi Sedigheh

    2016-09-01

    Chemical reagents that are used for synthesis of nanoparticles are often toxic, while biological reagents are safer and cost-effective. Here, the behavior of Staphylococcus epidermidis (ATCC 12228) was evaluated for biosynthesis of silver nanoparticles (Ag-NPs) and cadmium sulfide nanoparticles (CdS-NPs) using TEM images intra- and extracellularly. The bacteria only biosynthesized the nanoparticles intracellularly and distributed Ag-NPs throughout the cytoplasm and on outside surface of cell walls, while CdS-NPs only formed in cytoplasm near the cell wall. A new method for purification of the nanoparticles was used. TEM images of pure CdS-NPs confirmed biosynthesis of agglomerated nanoparticles. Biosynthetic Ag-NPs were more stable against bright light and aggregation reaction than synthetic Ag-NPs (prepared chemically) also biosynthetic Ag-NPs displayed lower toxicity in in vitro assays. CdS-NPs indicated no toxicity in in vitro assays. Biosynthetic nanoparticles as product of the detoxification pathway may be safer and more stable for biosensors. PMID:27430507

  18. In Vitro Toxicity Evaluation of Engineered Cadmium-Coated Silica Nanoparticles on Human Pulmonary Cells

    Directory of Open Access Journals (Sweden)

    Uliana De Simone

    2013-01-01

    Full Text Available Cytotoxicity of cadmium-containing silica nanoparticles Cd-SiO2NPs (0.05–100 µg/mL versus SiO2NPs and CdCl2 was evaluated by an in vitro test battery in A549 by assessing (i mitochondrial function, (ii membrane integrity/cell morphology, (iii cell growth/proliferation, (iv apoptotic pathway, (v oxidative stress, after short- (24–48 h and long-term (10 days exposure. Both Cd-SiO2NPs and CdCl2 produced dose-dependent cytotoxic effects: (i MTT-assay: similar cytotoxicity pattern was observed at both 24 and 48 h, with a more Cd-SiO2NPs pronounced effect than CdCl2. Cd-SiO2NPs induced mortality (about 50% at 1 μg/mL, CdCl2 at 25 μg/mL; (ii calcein-AM/PI staining: decrease in cell viability, noticeable at 25 μg/mL, enhanced markedly at 50 and 100 μg/mL, after 24 h. Cd-SiO2NPs induced higher mortality than CdCl2 (25% versus 4%, resp., at 25 μg/mL with further exacerbation after 48h; (iii clonogenic assay: exposure for longer period (10 days compromised the A549 proliferative capacity at very low dose (0.05 μg/mL; (iv a progressive activation of caspase-3 immunolabelling was detected already at 1 μg/mL; (v GSH intracellular level was modified by all compounds. In summary, in vitro data demonstrated that both Cd-SiO2NPs and CdCl2 affected all investigated endpoints, more markedly after Cd-SiO2NPs, while SiO2NPs influenced GSH only.

  19. Titanium dioxide nanoparticles modulate the toxicological response to cadmium in the gills of Mytilus galloprovincialis

    International Nuclear Information System (INIS)

    Highlights: • Nano-TiO2 modulate CdCl2 cellular responses in gills of marine mussel. • Nano-TiO2 reduced CdCl2-induced effects by lowering abcb1 m-RNA and GST activity. • Nano-TiO2 reduced Cd accumulation in mussel’s gills but not in whole soft tissue. • Higher accumulation of Ti in the presence of CdCl2 was observed in gills. - Abstract: We investigated the influence of titanium dioxide nanoparticles (nano-TiO2) on the response to cadmium in the gills of the marine mussel Mytilus galloprovincialis in terms of accumulation and toxicity. Mussels were in vivo exposed to nano-TiO2, CdCl2, alone and in combination. Several cellular biomarkers were investigated in gills: ABC transport proteins and metallothioneins at gene/protein (abcb1, abcc-like and mt-20) and functional level, GST activity, NO production and DNA damage (Comet assay). Accumulation of total Cd and titanium in gills as in whole soft tissue was also investigated. Significant responses to Cd exposure were observed in mussel gills as up-regulation of abcb1 and mt-20 gene transcription, increases in total MT content, P-gp efflux and GST activity, DNA damage and NO production. Nano-TiO2 alone increased P-gp efflux activity and NO production. When combined with Cd, nano-TiO2 reduced the metal-induced effects by significantly lowering abcb1 gene transcription, GST activity, and DNA damage, whereas, additive effects were observed on NO production. A lower concentration of Cd was observed in the gills upon co-exposure, whereas, Ti levels were unaffected. A competitive effect in uptake/accumulation of nano-TiO2 and Cd seems to occur in gills. A confirmation is given by the observed absence of adsorption of Cd onto nano-TiO2 in sea water media

  20. Synthesis and characterization of CdS and CdSe nanoparticles prepared from novel intramolecularly stabilized single-source precursors

    Indian Academy of Sciences (India)

    Karuppasamy Kandasamy; Harkesh B Singh; Shailendra K Kulshreshtha

    2009-05-01

    In this note we describe the synthesis of cadmium sulphide and selenide nanoparticles from the corresponding novel single source precursors, M[E(Ox)]2 [E = S (1), Se (2); M = Cd; Ox = 2-(4,4-dimethyl-2-oxazolinyl)benzene] by thermolysing in tri--octylphosphine oxide (TOPO) at 280°C, and their characterization by X-ray powder diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM) studies.

  1. New barium tantalum sulphides

    International Nuclear Information System (INIS)

    A new barium tantalum sulphide has been synthesized by the reaction of CS2 with a mixture of BaCO3 and Ta2O5. The chemical analysis of the compound was performed for 3 components (Ba, Ta and S), and the chemical composition was found to be BaTa2S5. The powder X-ray diffraction peaks were indexable on the basis of a hexagonal cell with lattices constants of a=3.32A, c=25.13A. However, the electron diffraction measurements show that the structure is more complex than that observed by powder X-ray diffraction. The compound indicates metallic behavior and Pauli paramagnetism

  2. Titanium dioxide nanoparticles modulate the toxicological response to cadmium in the gills of Mytilus galloprovincialis

    Energy Technology Data Exchange (ETDEWEB)

    Della Torre, Camilla [Department of Physical, Earth and Environmental Sciences, University of Siena (Italy); Balbi, Teresa [Department of Earth, Environmental and Life Sciences-DISTAV, University of Genoa (Italy); Grassi, Giacomo [Department of Physical, Earth and Environmental Sciences, University of Siena (Italy); Frenzilli, Giada; Bernardeschi, Margherita [Department of Clinical and Experimental Medicine, University of Pisa (Italy); Smerilli, Arianna [Department of Environmental, Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), Seconda Università di Napoli, Caserta (Italy); Guidi, Patrizia [Department of Clinical and Experimental Medicine, University of Pisa (Italy); Canesi, Laura [Department of Earth, Environmental and Life Sciences-DISTAV, University of Genoa (Italy); Nigro, Marco [Department of Clinical and Experimental Medicine, University of Pisa (Italy); Monaci, Fabrizio [Department of Physical, Earth and Environmental Sciences, University of Siena (Italy); Scarcelli, Vittoria [Department of Clinical and Experimental Medicine, University of Pisa (Italy); Rocco, Lucia [Department of Environmental, Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), Seconda Università di Napoli, Caserta (Italy); Focardi, Silvano [Department of Physical, Earth and Environmental Sciences, University of Siena (Italy); Monopoli, Marco [Centre for BioNanoInteractions, School of Chemistry and Chemical Biology, University College Dublin (Ireland); Corsi, Ilaria, E-mail: ilaria.corsi@unisi.it [Department of Physical, Earth and Environmental Sciences, University of Siena (Italy)

    2015-10-30

    Highlights: • Nano-TiO{sub 2} modulate CdCl{sub 2} cellular responses in gills of marine mussel. • Nano-TiO{sub 2} reduced CdCl{sub 2}-induced effects by lowering abcb1 m-RNA and GST activity. • Nano-TiO{sub 2} reduced Cd accumulation in mussel’s gills but not in whole soft tissue. • Higher accumulation of Ti in the presence of CdCl{sub 2} was observed in gills. - Abstract: We investigated the influence of titanium dioxide nanoparticles (nano-TiO{sub 2}) on the response to cadmium in the gills of the marine mussel Mytilus galloprovincialis in terms of accumulation and toxicity. Mussels were in vivo exposed to nano-TiO{sub 2}, CdCl{sub 2}, alone and in combination. Several cellular biomarkers were investigated in gills: ABC transport proteins and metallothioneins at gene/protein (abcb1, abcc-like and mt-20) and functional level, GST activity, NO production and DNA damage (Comet assay). Accumulation of total Cd and titanium in gills as in whole soft tissue was also investigated. Significant responses to Cd exposure were observed in mussel gills as up-regulation of abcb1 and mt-20 gene transcription, increases in total MT content, P-gp efflux and GST activity, DNA damage and NO production. Nano-TiO{sub 2} alone increased P-gp efflux activity and NO production. When combined with Cd, nano-TiO{sub 2} reduced the metal-induced effects by significantly lowering abcb1 gene transcription, GST activity, and DNA damage, whereas, additive effects were observed on NO production. A lower concentration of Cd was observed in the gills upon co-exposure, whereas, Ti levels were unaffected. A competitive effect in uptake/accumulation of nano-TiO{sub 2} and Cd seems to occur in gills. A confirmation is given by the observed absence of adsorption of Cd onto nano-TiO{sub 2} in sea water media.

  3. Risks of Cadmium Nanoparticles on Estuarine Organisms : Ecotoxicological Effects of Engineered Cadmium Nanoparticles through Biochemical and Behavioral Responses in Two Marine Invertebrates, Nereis diversicolor and Scrobicularia plana

    OpenAIRE

    Wu, Pianpian

    2012-01-01

    There is an increasing concern over the safety of engineered nanoparticles (ENPs) to humans and the environment. It is important that the environmental risks of these particles to be tested under research and regulatory schemes, e.g. Nano Risks to the environment & Human Health (NanoReTox) under Seventh Framework Programme (FP7) in EU. Due to their unique properties and the fact that their detection and characterization in complex matrices is challenging, classic analytical methods and te...

  4. Evolution of different morphologies of CdS nanoparticles by thermal decomposition of bis(thiourea)cadmium chloride in various solvents

    Energy Technology Data Exchange (ETDEWEB)

    Gaur, Rama; Jeevanandam, P., E-mail: jeevafcy@iitr.ernet.in, E-mail: jeevafcy@iitr.ac.in [Indian Institute of Technology Roorkee, Department of Chemistry (India)

    2015-03-15

    CdS nanoparticles with different morphologies have been synthesized by thermal decomposition of bis(thiourea)cadmium chloride in different solvents without the use of any ligand/surfactant. CdS nanoparticles with pyramid, sponge-like and hexagonal disc-like morphologies were obtained in diphenyl ether (DPE), 1-octadecene (ODE) and ethylene glycol (EG), respectively. In addition, CdS nanoparticles with unique morphologies were obtained when the decomposition of the complex was carried out in mixed solvents (DPE–EG and ODE–EG). Extensive characterization of the CdS nanoparticles was carried out using powder X-ray diffraction, FT-IR spectroscopy, thermal analysis, field-emission scanning electron microscopy, diffuse reflectance spectroscopy and photoluminescence spectroscopy, and detailed mechanism of the formation of CdS nanoparticles with different morphologies in various solvents has been proposed.

  5. Morphological and cytohistochemical evaluation of renal effects of cadmium-doped silica nanoparticles given intratracheally to rat

    Science.gov (United States)

    Coccini, T.; Roda, E.; Barni, S.; Manzo, L.

    2013-04-01

    Renal morphological parameters were determined in rats intratracheally instilled with model cadmium-containing silica nanoparticles (Cd-SiNPs, 1mg/rat), also exploring whether their potential modifications would be associated with toxicogenomic changes. Cd-SiNP effects, evaluated 7 and 30 days post-exposure, were assessed by (i) histopathology (Haematoxylin/Eosin Staining), (ii) characterization of apoptotic features by TUNEL staining. Data were compared with those obtained by CdCl2 (400μg/rat), SiNPs (600μg/rat), 0.1 ml saline. Area-specific cell apoptosis was observed in all treatment groups: cortex and inner medulla were the most affected regions. Apoptotic changes were apparent at 7 days post-exposure in both areas, and were still observable in inner medulla 30 days after treatment. Increase in apoptotic frequency was more pronounced in Cd-SiNP-treated animals compared to either CdCl2 or SiNPs. Histological findings showed comparable alterations in the renal glomerular (cortex) architecture occurring in all treatment groups at both time-points considered. The glomeruli appeared often collapsed, showing condensed, packed mesangial and endothelial cells. Oedematous haemorrhagic glomeruli were also observed in Cd-SiNPs-treated animals. Bare SiNPs caused morphological and apoptotic changes without modifying the renal gene expression profile. These findings support the concept that multiple assays and an integrated testing strategy should be recommended to characterize toxicological responses to nanoparticles in mammalian systems.

  6. Preparation of modified magnetic nanoparticles as a sorbent for the preconcentration and determination of cadmium ions in food and environmental water samples prior to flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mirabi, Ali; Dalirandeh, Zeinab [Department of Chemistry, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of); Rad, Ali Shokuhi, E-mail: a.shokuhi@qaemshahriau.ac.ir [Department of Chemical Engineering, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of)

    2015-05-01

    A new method has been developed for the separation/preconcentration of trace level cadmium ions using diphenyl carbazone/sodium dodecyl sulfate immobilized on magnetic nanoparticle Fe{sub 3}O{sub 4} as a new sorbent SPE and their determination by flame atomic absorption spectrometry (FAAS). Synthesized nanoparticle was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). Various influencing parameters on the separation and preconcentration of trace level cadmium ions such as, pH value, amount of nanoparticles, amount of diphenyl carbazone, condition of eluting solution, the effects of matrix ions were examined. The cadmium ions can be eluted from the modified magnetic nanoparticle using 1 mol L{sup −1} HCl as a desorption reagent. The detection limit of this method for cadmium was 3.71 ng ml{sup −1} and the R.S.D. was 0.503% (n=6). The advantages of this new method include rapidity, easy preparation of sorbents and a high concentration factor. The proposed method has been applied to the determination of Cd ions at trace levels in real samples such as, green tea, rice, tobacco, carrot, lettuce, ginseng, spice, tap water, river water, sea water with satisfactory results. - Highlights: • MNPs method is economical, simple, rapid and sensitive for trace analysis of Cd. • High preconcentration factor was obtained easily through this method. • A detection limit at ng mL{sup −1} level was achieved with 100.0 mL of sample. • This method provides good repeatability and extraction efficiency in a short time.

  7. Preparation of modified magnetic nanoparticles as a sorbent for the preconcentration and determination of cadmium ions in food and environmental water samples prior to flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    A new method has been developed for the separation/preconcentration of trace level cadmium ions using diphenyl carbazone/sodium dodecyl sulfate immobilized on magnetic nanoparticle Fe3O4 as a new sorbent SPE and their determination by flame atomic absorption spectrometry (FAAS). Synthesized nanoparticle was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). Various influencing parameters on the separation and preconcentration of trace level cadmium ions such as, pH value, amount of nanoparticles, amount of diphenyl carbazone, condition of eluting solution, the effects of matrix ions were examined. The cadmium ions can be eluted from the modified magnetic nanoparticle using 1 mol L−1 HCl as a desorption reagent. The detection limit of this method for cadmium was 3.71 ng ml−1 and the R.S.D. was 0.503% (n=6). The advantages of this new method include rapidity, easy preparation of sorbents and a high concentration factor. The proposed method has been applied to the determination of Cd ions at trace levels in real samples such as, green tea, rice, tobacco, carrot, lettuce, ginseng, spice, tap water, river water, sea water with satisfactory results. - Highlights: • MNPs method is economical, simple, rapid and sensitive for trace analysis of Cd. • High preconcentration factor was obtained easily through this method. • A detection limit at ng mL−1 level was achieved with 100.0 mL of sample. • This method provides good repeatability and extraction efficiency in a short time

  8. Synthesis and optical properties of CdS/ZnS coreshell nanoparticles

    International Nuclear Information System (INIS)

    Synthesis and optical properties of manganese (Mn2+)-doped, polyvinyl pyrrolidone (PVP)-capped cadmium sulphide (CdS) nanoparticles coated with zinc sulphide (ZnS) are reported. Colloidal solution of Mn2+-doped CdS nanoparticles capped with PVP is synthesized using methanol as solvent. PVP is used to control the particle size and to prevent agglomeration. Mn2+ doping is expected to help in increasing the CdS band edge photoluminescence (PL) emission. Addition of zinc nitrate and sodium sulphide alternately to the Mn2+-doped, PVP-stabilized CdS colloid led to the formation of ZnS-coated CdS coreshell nanoparticles. Photoluminescence emission spectra recorded for (CdS-PVP)Mn nanoparticles showed two emission peaks, one at 416 nm and the other weaker peak at 586 nm which is attributed to Mn2+ emission. Intensity of Mn2+ peak increased with increase in the Mn2+ content. Mn2+ emission disappears when ZnS is coated over the CdS core, resulting in pure CdS band edge emission

  9. Fluorescent cadmium sulfide nanoparticles for selective and sensitive detection of toxic pesticides in aqueous medium

    International Nuclear Information System (INIS)

    The detection of pesticide residues in ground water, food, or soil samples is extremely important. The currently available laboratory techniques have several drawbacks and needs to be replaced. Fluorescent chemosensors for pesticide detection were reported in the literature, with few reports published on quantum dot-based pesticide sensors, but none of these were focused toward differentiating organophosphorus and organochlorine pesticides specifically. In this respect, glutathione-coated CdS nanoparticles were synthesized and characterized. The TEM studies of the nanoparticles suggested mostly monodispersed spherical particles, with size in the range of 11.5±1 nm. The prepared fluorescent nanoparticles were found to selectively recognize organochlorine pesticide dicofol among all the other pesticides studied, by increasing the fluorescence intensity of the nanoparticles ∼ 2.5 times. Similar studies carried out with organophosphorous pesticide dimethoate did not result any change in the fluorescence intensity of the nanoparticles. Further studies carried out with commercially available pesticide solutions, also confirmed similar results. The TEM, SEM, and DLS studies suggested aggregation of the nanoparticles in the presence of dicofol. Control experiments suggested possible role of both amine and carboxylic acid functional groups of glutathione in the recognition of dicofol. The limit of detection of dicofol was found to be ∼ 55±11 ppb.Graphical AbstractGlutathione-coated CdS nanoparticles selectively recognize organochlorine pesticide dicofol among all the other pesticides studied, by increasing the fluorescence intensity of the nanoparticles. The TEM, SEM, and DLS studies suggested aggregation of the nanoparticles in the presence of dicofol

  10. Fluorescent cadmium sulfide nanoparticles for selective and sensitive detection of toxic pesticides in aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Walia, Shanka; Acharya, Amitabha, E-mail: amitabhachem@gmail.com [CSIR-Institute of Himalayan Bioresource Technology, Biotechnology Division (India)

    2014-12-15

    The detection of pesticide residues in ground water, food, or soil samples is extremely important. The currently available laboratory techniques have several drawbacks and needs to be replaced. Fluorescent chemosensors for pesticide detection were reported in the literature, with few reports published on quantum dot-based pesticide sensors, but none of these were focused toward differentiating organophosphorus and organochlorine pesticides specifically. In this respect, glutathione-coated CdS nanoparticles were synthesized and characterized. The TEM studies of the nanoparticles suggested mostly monodispersed spherical particles, with size in the range of 11.5±1 nm. The prepared fluorescent nanoparticles were found to selectively recognize organochlorine pesticide dicofol among all the other pesticides studied, by increasing the fluorescence intensity of the nanoparticles ∼ 2.5 times. Similar studies carried out with organophosphorous pesticide dimethoate did not result any change in the fluorescence intensity of the nanoparticles. Further studies carried out with commercially available pesticide solutions, also confirmed similar results. The TEM, SEM, and DLS studies suggested aggregation of the nanoparticles in the presence of dicofol. Control experiments suggested possible role of both amine and carboxylic acid functional groups of glutathione in the recognition of dicofol. The limit of detection of dicofol was found to be ∼ 55±11 ppb.Graphical AbstractGlutathione-coated CdS nanoparticles selectively recognize organochlorine pesticide dicofol among all the other pesticides studied, by increasing the fluorescence intensity of the nanoparticles. The TEM, SEM, and DLS studies suggested aggregation of the nanoparticles in the presence of dicofol.

  11. Morphology and thermal studies of zinc sulfide and cadmium sulfide nanoparticles in polyvinyl alcohol matrix

    Science.gov (United States)

    Osuntokun, Jejenija; Ajibade, Peter A.

    2016-09-01

    Zn(II) and Cd(II) metal complexes of 1-cyano-1-carboethoxyethylene-2,2-dithiolato-κS,S'-bis(N,N-dimethylthiourea-κS) have been synthesized and characterized with analytical and spectroscopic techniques. The complexes were thermolysed in hexadecylamine at 200 °C to prepare ZnS and CdS nanoparticles. The nanoparticles were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), and powder X-ray diffraction (p-XRD). TEM images showed spherically shaped nanoparticles, whose sizes are in the range 4.33-7.21 nm for ZnS and 4.95-7.7 nm CdS respectively and XRD confirmed cubic crystalline phases for the nanoparticles. The optical band gap energy evaluated from the absorption spectra are 2.88 eV (430 nm) and 2.81 eV (440 nm) for the ZnS and CdS nanoparticles respectively. The as-prepared metal sulfide nanoparticles were further incorporated into polyvinyl alcohol (PVA) to give ZnS/PVA and CdS/PVA composites. The polymer nanocomposites were studied to investigate their morphology and thermal properties relative to the pure PVA. XRD diffractions indicated that the crystalline phases of the nanoparticles and the sizes in PVA matrices remained unaltered. Infra-red spectra studies revealed interactions between the PVA and the metal sulfide nanoparticles and TGA studies show that the ZnS/PVA and CdS/PVA nanocomposites exhibit better thermal stability than the pure PVA.

  12. Biological synthesis of fluorescent nanoparticles by cadmium and tellurite resistant Antarctic bacteria: exploring novel natural nanofactories

    OpenAIRE

    Plaza, D. O.; Gallardo, C.; Straub, Y. D.; Bravo, D.; Pérez-Donoso, J. M.

    2016-01-01

    Background Fluorescent nanoparticles or quantum dots (QDs) have been intensely studied for basic and applied research due to their unique size-dependent properties. There is an increasing interest in developing ecofriendly methods to synthesize these nanoparticles since they improve biocompatibility and avoid the generation of toxic byproducts. The use of biological systems, particularly prokaryotes, has emerged as a promising alternative. Recent studies indicate that QDs biosynthesis is rela...

  13. Thermo chemical stability of cadmium sulfide nanoparticles under intense pulsed light irradiation and high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Colorado, H.A., E-mail: hcoloradolopera@ucla.edu [Materials Science and Engineering Department, University of California, Los Angeles, CA 90095 (United States); Universidad de Antioquia, Mechanical Engineering, Medellin (Colombia); Dhage, S.R. [International Advanced Research Center for Powder Metallurgy and New Materials (ARCI), Hyderabad 500005 (India); Hahn, H.T. [Materials Science and Engineering Department, University of California, Los Angeles, CA 90095 (United States); Mechanical and Aerospace Engineering Department, University of California, Los Angeles (United States)

    2011-09-15

    Highlights: > In this paper is about the thermochemical stability of CdS nanoparticles under Intense Pulsed Light (IPL) irradiation. > After few irradiation shots over the nano-particles, CdS pillars appeared without phase transformation. > No oxidation was observed during the treatment process. > CdS nanoparticles are thermally stable until around 400 deg. C and 600 deg. C for air and argon atmospheres respectively. > It has been studied and demonstrated the stability of CdS nanoparticles under intense pulsed light and under high temperature conditions. - Abstract: Thermo chemical stability of CdS nanoparticles under an Intense Pulsed Light from a xenon flash lamp and high temperature X-ray Diffraction (XRD) were investigated. The CdS nanoparticles were obtained with a chemical bath method. The CdSO{sub 4} (0.16 M) solution was added to an NH{sub 3} (7.5 M) solution under constant stirring. Afterwards, a thiourea (0.6 M) solution was added. The bath temperature and pH were maintained at 65 deg. C and 10, respectively and the mixture was stirred constantly until a solid precipitate of yellow CdS was produced. Its microstructure was investigated with Scanning Electron Microscopy, and its electronic properties were determined by UV-visible and Photo luminescence Spectroscopy. The microstructure of the sintered CdS nanoparticles, obtained the high temperature XRD, was investigated with EDAX and X-ray micro Tomography. In addition, high temperature XRD and Themogravimetric Analysis tests were conducted over the samples. The CdS nanoparticles' crystallinity increased with the irradiation exposure and they were thermally stable until 600 deg. C in argon atmosphere. However new phases start to appear after annealing at 400 deg. C for 30 min in air atmosphere. The main contribution of this paper was to investigate the stability of CdS nanoparticles under intense light and high temperature conditions. It was found that the number of irradiation shots conducted with the

  14. Synthesis and shape control of copper tin sulphide nanocrystals and formation of gold-copper tin sulphide hybrid nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Kruszynska, Marta; Parisi, Juergen; Kolny-Olesiak, Joanna [Oldenburg Univ. (Germany). Inst. of Physics, Energy and Semiconductor Research Lab.

    2014-08-15

    Hexagonal prismatic Cu{sub 3}SnS{sub 4} nanoparticles and nanorods were synthesized by a hot-injection procedure. Changing the reaction conditions leads to the formation of different shapes. When oleylamine is used as a solvent, hexagonal prismatic particles are obtained, while a reaction in octadecene results in the formation of nanorods. The growth process of copper tin sulphide starts with the formation of djurleite copper sulphide seeds. Their reaction with Sn{sup 4+} ions leads to the formation of Cu{sub 3}SnS{sub 4}. These Cu{sub 3}SnS{sub 4} nanocrystals form Au-Cu{sub 3}SnS{sub 4} hybrid nanostructures by reaction with gold seeds.

  15. Photocatalytic Oxidation of Hydrosulfide Ions by Molecular Oxygen Over Cadmium Sulfide Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Raevskaya, A. E., E-mail: photochem@e-mail.ru; Stroyuk, A.L., E-mail: photochem@e-mail.ru; Kuchmii, S.Ya. [National Academy of Sciences of Ukraine, L. V. Pysarzhevsky Institute of Physical Chemistry (Ukraine)], E-mail: photochem@e-mail.ru

    2004-06-15

    Photocatalytic activity of CdS nanoparticles in hydrosulfide-ions air oxidation was revealed and thoroughly investigated. HS{sup -} photooxidation in the presence of CdS nanoparticles results predominantly in the formation of SO{sub 3}{sup 2-} and SO{sub 4}{sup 2-} ions. Photocatalytic activity of ultrasmall CdS crystallites in HS{sup -} photooxidation is much more pronounced as compared to bulk CdS crystals due to high surface area of nanoparticles, their negligible light scattering, improved separation of photogenerated charge carriers etc. It was shown that hydrosulfide ions can be oxidized in two ways. The first is HS{sup -} oxidation by the CdS valence band holes. This process rate depends on the rate of comparatively slow reaction between molecular oxygen and CdS conduction band electrons. The second reaction route is the chain-radical HS{sup -} oxidation induced by photoexcited CdS nanoparticles and propagating in the bulk of a solution. In conditions favourable to chain-radical oxidation of HS{sup -}(i.e. at low light intensities and CdS concentration and high oxygen and Na{sub 2}S concentrations) quantum yields of the photoreaction reach 2.5.

  16. Structural studies of thin films of semiconducting nanoparticles in polymer matrices

    Energy Technology Data Exchange (ETDEWEB)

    Di Luccio, Tiziana [ENEA, Centro Ricerche Brindisi, SS7 Appia Km 706, I-72100 Brindisi (Italy)], E-mail: tiziana.diluccio@portici.enea.it; Piscopiello, Emanuela; Laera, Anna Maria [ENEA, Centro Ricerche Brindisi, SS7 Appia Km 706, I-72100 Brindisi (Italy); Antisari, Marco Vittori [ENEA, Centro Ricerche Casaccia, Via Anguillarese 301, I-00060 S. Maria di Galeria (Roma) (Italy)

    2007-09-15

    Ordered films of nanoscale materials are issue of wide interest for applications in several fields, such as optics, catalysis, and bioelectronics. In particular, semiconducting nanoparticles incorporation in a processable polymer film is an easy way to manipulate such materials for their application. We deposited thin layers of cadmium sulphide (CdS) and zinc sulphide (ZnS) nanoparticles embedded in a thermoplastic cyclo-olephin copolymer (COC) with elevated optical transparency and highly bio-compatible. The nanoparticles were obtained by thiolate precursors previously dispersed in the polymer upon thermal treatment at temperatures ranging between 200 and 300 deg. C depending on the desired size. The precursor/polymer solutions were spin-coated in order to get thin films. The spinning conditions were changed in order to optimise the layer thickness and uniformity. The samples were mainly characterised by X-ray reflectivity (XRR) and by high-resolution transmission electron microscopy (HRTEM) analyses. The thinnest layer we have deposited is 8 nm thick, as evaluated by XRR. The HRTEM measurements showed that the nanoparticles have quasi-spherical shape without evident microstructural defects. The size of the nanoparticles depends on the annealing temperature, e.g. at 232 deg. C the size of the CdS nanoparticles is about 4-5 nm.

  17. Small angle X-ray and neutron scattering on cadmium sulfide nanoparticles in silicate glass

    Science.gov (United States)

    Kuznetsova, Yu. V.; Rempel, A. A.; Meyer, M.; Pipich, V.; Gerth, S.; Magerl, A.

    2016-08-01

    Small angle X-ray and neutron scattering on Cd and S doped glass annealed at 600 °C shows after the first 12 h nucleation and growth of spherical CdS nanoparticles with a radius of up to 34±4 Å. After the nucleation is completed after 24 h, further growth in this amorphous environment is governed by oriented particle attachment mechanism as found for a liquid medium. Towards 48 h the particle shape has changed into spheroidal with short and long axis of 40±2 Å and 120±2 Å, respectively.

  18. Competitive Adsorption of Cadmium (II from Aqueous Solutions onto Nanoparticles of Water Treatment Residual

    Directory of Open Access Journals (Sweden)

    Elsayed Elkhatib

    2016-01-01

    Full Text Available There is increasing interest in using water treatment residuals (WTRs for heavy metals removal from wastewater due to their low cost, availability, and high efficiency in removing various pollutants. In this study, novel water treatment residuals nanoparticles (nWTRs were prepared using high energy ball milling and used for efficient removal of Cd(II in single- and multi-ion systems. The WTR nanoparticles demonstrated high removal efficiency for Cd from aqueous solution as the adsorption capacities of nWTR were 17 and 10 times higher than those of bulk WTR in single- and multielement systems, respectively. Noticeably, Cd(II adsorption was clearly suppressed in the multi-ion system as Cu and Pb form the most stable monohydroxo complexes. Fourier transmission infrared (FTIR analyses suggested the participation of OH−, O-Al-O, FeOH, and FeOOH entities in the adsorption process. The stability of Cd-nWTR surface complexes is evident as less than 0. 2% of adsorbed Cd(ll was released at the highest Cd(II concentration load after 4 consecutive desorption cycles. Moreover, the real efficiency of nWTR for Cd(II removal from wastewater samples studied was calculated to be 98.35%. These results highlight the potential of nWTR for heavy metals removal from wastewater.

  19. Lead sulphide nanocrystal photodetector technologies

    Science.gov (United States)

    Saran, Rinku; Curry, Richard J.

    2016-02-01

    Light detection is the underlying principle of many optoelectronic systems. For decades, semiconductors including silicon carbide, silicon, indium gallium arsenide and germanium have dominated the photodetector industry. They can show excellent photosensitivity but are limited by one or more aspects, such as high production cost, high-temperature processing, flexible substrate incompatibility, limited spectral range or a requirement for cryogenic cooling for efficient operation. Recently lead sulphide (PbS) nanocrystals have emerged as one of the most promising new materials for photodetector fabrication. They offer several advantages including low-cost manufacturing, solution processability, size-tunable spectral sensitivity and flexible substrate compatibility, and they have achieved figures of merit outperforming conventional photodetectors. We review the underlying concepts, breakthroughs and remaining challenges in photodetector technologies based on PbS nanocrystals.

  20. Marine fuels and hydrogen sulphide

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, N.; Antunez Martel, F.J.; Bonini, A.; Buhaug, O.; Chevallier, F.; Heyberger, B.; Hovius, H.; Jansen, L.; Pocek, V.; Ramos, A.P.; Sasloglou, S.; Seppaalaa, K.; Steernberg, K.; Terschek, R.; Vermeire, M.; Rose, K.D.

    2013-10-15

    The safe handling of petroleum cargoes and refined products that may contain hydrogen sulphide (H2S) is an important issue for the marine and inland fuel industries. Attention has refocused recently on H2S due to the revision of the ISO 8217:2012 specification for marine fuels which limited the maximum content of H2S in the liquid fuel to 2.00 mg H2S/kg fuel (2.00 ppmw). This report summarizes issues associated with the presence of H2S in residual marine fuels including: Sources of H2S in petroleum products; Exposure levels for H2S in the vapour phase and the effects of exposure; Relationship between the H2S concentration in liquid fuel and in the vapour phase; Measurement methods for H2S in marine fuel and in the vapour phase; Interpretation of results and guidance on maximum H2S levels; and Guidelines for the safe handling of liquid petroleum products that may contain H2S. Importantly, the report reinforces the need for safe handling procedures , training, and personnel protection when transferring or storing fuels that may contain H2S, rather than relying only on a measured H2S level in the liquid product.

  1. Graphene ultrathin film electrodes modified with bismuth nanoparticles and polyaniline porous layers for detection of lead and cadmium ions in acetate buffer solutions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaomeng; Li, Lin; Liu, Erjia, E-mail: mejliu@ntu.edu.sg

    2013-10-01

    Graphene ultrathin films were synthesized by means of solid-state carbon diffusion from amorphous carbon (a-C) thin layers deposited on silicon substrates, which was catalyzed by nickel layers coated on the top of the a-C layers. The graphene films were used as working electrodes that were modified by a polyaniline (PANI) porous layer together with in-situ deposited bismuth (Bi) nanoparticles for the detection of trace heavy metal ions (Pb{sup 2+} and Cd{sup 2+}) in acetate buffer solutions (pH 5.3) with square wave anodic stripping voltammetry. The graphene electrodes modified with PANI porous layers and Bi nanoparticles had excellent repeatability, ultrahigh sensitivity (as low as 0.33 nM) and good resistance to passivation caused by the surface active species adsorbed on the electrode surfaces. - Highlights: • Graphene fabricated by nickel-catalyzed carbon diffusion in solid state • Graphene electrodes modified by bismuth nanoparticles and polyaniline layers • High resistance of modified graphene electrodes to passivation in acetate solutions • Ultra-low detection limits of lead and cadmium ions by modified graphene electrodes.

  2. Supported hydrophobic ionic liquid on magnetic nanoparticles as a new sorbent for separation and preconcentration of lead and cadmium in milk and water samples

    International Nuclear Information System (INIS)

    We have prepared a highly selective and efficient sorbent for the simultaneous separation and preconcentration of lead and cadmium ions from milk and water samples. An ionic liquid was deposited on the surface of magnetic nanoparticles (IL-MNPs) and used for solid phase extraction of these ions. The IL-MNPs carrying the target metals were then separated from the sample solution by applying an external magnetic field. Lead and cadmium were almost quantitatively retained by the IL-MNPs, and then eluted with nitric acid. The effect of different variables on solid phase extraction was investigated. The calibration curve is linear in the range from 0.3 to 20 ng mL-1 of Cd(II), and from 5 to 330 ng mL-1 of Pb(II) in the initial solution. Under optimum conditions, the detection limits are 1.61 and 0.122 μg L-1 for Pb(II) and Cd(II) respectively. Relative standard deviations (n=10) were 2.87 % and 1.45 % for 0.05 μg mL-1 and 0.2 μg mL-1 of Cd (II) and Pb (II) respectively. The preconcentration factor is 200 for both of ions. (author)

  3. Bis(3-methyl-2-pyridyl)ditelluride and pyridyl tellurolate complexes of zinc, cadmium, mercury: Synthesis, characterization and their conversion to metal telluride nanoparticles.

    Science.gov (United States)

    Kedarnath, G; Jain, Vimal K; Wadawale, Amey; Dey, Gautam K

    2009-10-21

    Treatment of an acetonitrile solution of metal chloride with bis(3-methyl-2-pyridyl)ditelluride, [Te(2)(pyMe)(2)], in the same solvent yielded complexes of composition [MCl(2){Te(2)(pyMe)(2)}] (M = Zn or Cd) whereas reactions of [MCl(2)(tmeda)] with NaTepyR (R = H or Me) gave tellurolate complexes of the general formula [M(TepyR)(2)] (M = Cd or Hg). When the cadmium complex [Cd(Tepy)(2)] was crystallized in the presence of excess tmeda, [Cd(Tepy)(2)(tmeda)] was formed exclusively. These complexes were characterized by elemental analyses, uv-vis, (1)H NMR data. The crystal structures of [ZnCl(2){Te(2)(pyMe)(2)}] and [Cd(Tepy)(2)(tmeda)] were established by single crystal X-ray diffraction. In the former zinc is coordinated to nitrogen atoms of the pyridyl group, while in the latter the coordination environment around tetrahedral cadmium is defined by the two neutral nitrogen atoms of tmeda, and two pyridyl tellurolate ligands. Thermal behavior of some of these complexes was studied by thermogravimetric analysis. Pyrolysis of [M(Tepy)(2)] in a furnace or in coordinating solvents such as hexadecylamine/tri-n-octylphosphine oxide (HDA/TOPO) at 350 and 160 degrees C, respectively gave MTe nanoparticles, which were characterized by uv-vis, photoluminiscence, XRD, EDAX and TEM.

  4. Mesophilic leaching of copper sulphide sludge

    Directory of Open Access Journals (Sweden)

    VLADIMIR B. CVETKOVSKI

    2009-02-01

    Full Text Available Copper was precipitated using a sodium sulphide solution as the precipitation agent from an acid solution containing 17 g/l copper and 350 g/l sulphuric acid. The particle size of nearly 1 µm in the sulphide sludge sample was detected by optical microscopy. Based on chemical and X-ray diffraction analyses, covellite was detected as the major sulphide mineral. The batch bioleach amenability test was performed at 32 °C on the Tk31 mine mesophilic mixed culture using a residence time of 28 days. The dissolution of copper sulphide by direct catalytic leaching of the sulphides with bacteria attached to the particles was found to be worthy, although a small quantity of ferrous ions had to be added to raise the activity of the bacteria and the redox potential of the culture medium. Throughout the 22-day period of the bioleach test, copper recovery based on residue analysis indicated a copper extraction of 95 %, with copper concentration in the bioleach solution of 15 g/l. The slope of the straight line tangential to the exponential part of the extraction curve gave a copper solubilisation rate of 1.1 g/l per day. This suggests that a copper extraction of 95 % for the period of bioleach test of 13.6 days may be attained in a three-stage bioreactor system.

  5. Heavy metal adsorption by sulphide mineral surfaces

    Science.gov (United States)

    Jean, Gilles E.; Bancroft, G. Michael

    1986-07-01

    The adsorption of aqueous Hg 2+, Pb 2+, Zn 2+ and Cd 2+ complexes on a variety of sulphide minerals has been studied as a function of the solution pH and also as a function of the nature of the ligands in solution. Sulphide minerals are excellent scavengers for these heavy metals. The adsorption is strongly pH dependent, i.e. there is a critical pH at which the adsorption increases dramatically. The pH dependence is related to the hydrolysis of the metal ions. Indirect evidence suggests that the hydrolyzed species are adsorbed directly on the sulphide groups, probably as a monolayer. The results also suggest the presence of MCI n2- n species physisorbed on the adsorbed monolayer. A positive identification of the adsorbed species was not possible using ESCA/XPS.

  6. The endogenous production of hydrogen sulphide in intrauterine tissues

    OpenAIRE

    Wang Rui; Heptinstall John; Vatish Manu; Patel Pushpa; Carson Ray J

    2009-01-01

    Abstract Background Hydrogen sulphide is a gas signalling molecule which is produced endogenously from L-cysteine via the enzymes cystathionine beta-synthase (CBS) and cystathionine gamma-lyase (CSE). The possible role of hydrogen sulphide in reproduction has not yet been fully investigated. It has been previously demonstrated that hydrogen sulphide relaxes uterine smooth muscle in vitro. The aim of the present study was to investigate the endogenous production of hydrogen sulphide in rat and...

  7. Cadmium carcinogenesis

    International Nuclear Information System (INIS)

    Cadmium is a heavy metal of considerable environmental and occupational concern. Cadmium compounds are classified as human carcinogens by several regulatory agencies. The most convincing data that cadmium is carcinogenic in humans comes from studies indicating occupational cadmium exposure is associated with lung cancer. Cadmium exposure has also been linked to human prostate and renal cancer, although this linkage is weaker than for lung cancer. Other target sites of cadmium carcinogenesis in humans, such as liver, pancreas and stomach, are considered equivocal. In animals, cadmium effectively induces cancers at multiple sites and by various routes. Cadmium inhalation in rats induces pulmonary adenocarcinomas, in accord with its role in human lung cancer. Cadmium can induce tumors and/or preneoplastic lesions within the rat prostate after ingestion or injection. At relatively high doses, cadmium induces benign testicular tumors in rats, but these appear to be due to early toxic lesions and loss of testicular function, rather than from a specific carcinogenic effect of cadmium. Like many other metals, cadmium salts will induce mesenchymal tumors at the site of subcutaneous (s.c.) or intramuscular (i.m.) injections, but the human relevance of these is dubious. Other targets of cadmium in rodents include the liver, adrenal, pancreas, pituitary, and hematopoietic system. With the exception of testicular tumors in rodents, the mechanisms of cadmium carcinogenesis are poorly defined. Cadmium can cause any number of molecular lesions that would be relevant to oncogenesis in various cellular model systems. Most studies indicate cadmium is poorly mutagenic and probably acts through indirect or epigenetic mechanisms, potentially including aberrant activation of oncogenes and suppression of apoptosis

  8. The toxic effects of l-Cysteine-capped cadmium sulfide nanoparticles on the aquatic plant Spirodela polyrrhiza

    Energy Technology Data Exchange (ETDEWEB)

    Khataee, Alireza, E-mail: ar_khataee@yahoo.com [University of Tabriz, Research Laboratory of Advanced Water and Wastewater Treatment Processes, Department of Applied Chemistry, Faculty of Chemistry (Iran, Islamic Republic of); Movafeghi, Ali [University of Tabriz, Department of Plant Biology, Faculty of Natural Sciences (Iran, Islamic Republic of); Nazari, Fatemeh [University of Tabriz, Research Laboratory of Advanced Water and Wastewater Treatment Processes, Department of Applied Chemistry, Faculty of Chemistry (Iran, Islamic Republic of); Vafaei, Fatemeh [University of Tabriz, Department of Plant Biology, Faculty of Natural Sciences (Iran, Islamic Republic of); Dadpour, Mohammad Reza [University of Tabriz, Department of Horticultural Science, Faculty of Agriculture (Iran, Islamic Republic of); Hanifehpour, Younes; Joo, Sang Woo, E-mail: swjoo@yu.ac.kr [Yeungnam University, School of Mechanical Engineering (Korea, Republic of)

    2014-12-15

    Plants play an important role in the fate of nanoparticles in the environment through their uptake, bioaccumulation, and transfer to trophic chains. However, the impacts of nanoparticles on plants as essential components of all ecosystems are not well documented. In the present study, the toxic effects of l-Cysteine-capped CdS nanoparticles on Spirodela polyrrhiza as an aquatic higher plant species were studied. l-Cysteine-capped CdS nanoparticles were synthesized using hydrothermal method and their characteristics were determined by XRD, SEM, HR-TEM, and FT-IR techniques. The diameter of majority of synthesized nanoparticles was about 15–20 nm. Subsequently, the uptake of l-Cysteine-capped CdS nanoparticles by the plant species was confirmed using epifluorescence microscopy. The activity of peroxidase and superoxide dismutase as antioxidant enzymes was assayed and the relative frond number was calculated in the presence of different concentrations of l-Cysteine-capped CdS nanoparticles. The obtained results revealed the toxic effects of the synthesized nanoparticles on S. polyrrhiza, leading to growth reduction and significant changes in antioxidant enzymes’ activity.Graphical Abstract.

  9. Covalent attachment of thionine onto gold electrode modified with cadmium sulfide nanoparticles: Improvement of electrocatalytic and photelectrocatalytic reduction of hydrogen peroxide

    International Nuclear Information System (INIS)

    A newly developed strategy based on gold (Au) electrode modified with cadmium sulfide nanoparticles (CdSnp) and thionine (Th) was proposed toward electrocatalytic and photoelectrocatalytic hydrogen peroxide (H2O2) reduction. At first, a thin film of CdS nanoparticles was electrodeposited onto Au electrode. Then, the CdS/Au electrode was modified with mercaptoacetic acid (MAA), which not only acts as a stabilizing agent to prevent the chalcogenide CdS nanocrystals from aggregation but also as a linker for subsequent attachment of Th onto the CdS nanoparticles. The effective covalent immobilization of Th was achieved through amide bond formation reaction between -NH2 groups of Th and -COOH groups of MAA, using dicyclohexylcarbodiimide (DCC) as condensation agent. The Au/CdS/Th modified electrode showed a well-defined redox couple with surface confined characteristics at wide pH range (2–12). The heterogeneous electron transfer rate constant (ks) and the surface coverage of immobilized Th on the modified electrode was obtained as 0.12 s−1 and 4.35 × 10−9 mole cm−2, respectively. The electrocatalytic activity and stability of the modified electrode toward hydrogen peroxide reduction was investigated and it was found that the Au/CdS/Th electrode illustrates excellent electrocatalytic activity toward H2O2 reduction at reduced overpotential. The detection limit, sensitivity and catalytic rate constant (kcat) of the modified electrode toward H2O2 were 55 nM, 3.4 μA μM−1 cm−2 and 3.75 (±0.1) × 103 M−1 s−1, respectively, at linear concentration range up to 10 mM. Upon light irradiation, about two-fold improvements were attained in sensitivity and detection limit of the modified electrode toward H2O2 electrocatalytic determination

  10. Structures and properties of vanadium sulphides

    NARCIS (Netherlands)

    Vries, Ajran Brugt de

    1972-01-01

    The chalcogenides ( sulphides, selenides, tellurides ) of the transition metals have received considerable attention in the last decennia. This is a consequence of the fact that these materials show a great variety of magnetic and electrical properties. The large number of compounds that can occur i

  11. Determination of sulphides in cements by using potentiometry with a selective electrode of sulphides

    Directory of Open Access Journals (Sweden)

    Bernal, José Luis

    1988-03-01

    Full Text Available A procedure for the determination of sulphides attackable by HCI (1 :3 in cements by means of a potentiometric determination with a selective electrodo of sulphides, is proposed.

    Se propone un método para la determinación de sulfuros, basado en el ataque con HCI (1:3, destilación y posterior medida potenciométrica con un electrodo selectivo de sulfuros.

  12. Removal of Hydrogen Sulphide from Water

    Directory of Open Access Journals (Sweden)

    S. Edwards

    2011-01-01

    Full Text Available Problem statement: The concentration of H2S in groundwater is a significant problem in various areas across Canada. Hydrogen sulphide dissolves in ground water imparting undesirable taste and irritating rotten egg smell which makes it unpalatable. Ingestion of sulphides through drinking water can result in stomach discomfort, nausea and vomiting. Humans exposed to high concentrations of H2S for prolonged periods show symptoms of gastro-intestinal upset, anorexia, nausea, somnolence, amnesia, loss of consciousness, delirium, hallucinations, difficulty in swallowing, low blood pressure, slowing of heart rate, double vision and epileptiform convulsions. Hydrogen sulphide in blood is rapidly oxidized by molecular oxygen and thus reduces the oxidation power of haemoglobin. Unoxidized hydrogen sulphide can act upon the central nervous system and cause either paralysis or respiratory failure. It is therefore, necessary to have a very low concentration of H2S in the water. Approach: An automatic system for the addition of KMnO4 and removal of hydrogen sulphide from ground water was developed and tested. The system consisted of a freshwater tank, a pump, a chemical storage tank, a solenoid valve, a photocell and electronic circuit, a drainage tank, a filter and a set of valves. It was possible to use a photocell to detect the presence of excess KMnO4 in the system and to control the addition of KMnO4 into the system. Results: The system accomplished complete removal of hydrogen sulphide in the range of 1-30 ppm. The present system utilizes on/off control for the addition of the chemical. The amount of KMnO4 needed as a percentage of the amount used was in the range of 5-28%. Conclusion: The photocell and circuit could be used to add an amount of chemical that is constantly proportional to the amount of hydrogen sulphide in the water. The control of a positive displacement chemical feed pump would be an ideal application for this system. The speed of the

  13. Synthesis, characterization and biocompatibility of cadmium sulfide nanoparticles capped with dextrin for in vivo and in vitro imaging application

    OpenAIRE

    Reyes-Esparza, Jorge; Martínez-Mena, Alberto; Gutiérrez-Sancha, Ivonne; Rodríguez-Fragoso, Patricia; de la Cruz, Gerardo Gonzalez; Mondragón, R.; Rodríguez-Fragoso, Lourdes

    2015-01-01

    Background The safe use in biomedicine of semiconductor nanoparticles, also known as quantum dots (QDs), requires a detailed understanding of the biocompatibility and toxicity of QDs in human beings. The biological characteristics and physicochemical properties of QDs entail new challenges regarding the management of potential adverse health effects following exposure. At certain concentrations, the synthesis of semiconductor nanoparticles of CdS using dextrin as capping agent, at certain con...

  14. Synthesis and characterization of cadmium selenide and indium sulfide nanoparticles and their surface modification using rubidium(bipy) chloride complex

    Science.gov (United States)

    Kudanalli Nagesha, Dattatri Jois

    2002-08-01

    Scope and method of study. The purpose of this study was to investigate new synthetic routes to make stable CdSe and In2S 3 nanoparticles. On these newly synthesized nancolloids, the surface modification was attempted via the chalcogen sites. A mixed metal-ligand complex of Ru(bipy)2Cl2 was used for this purpose. The synthesized nanoparticles and the surface modification reaction were monitored by a changes in the UV-vis absorption spectroscopy, steady state luminescence, time resolved photoluminescence, transmission electron microscopy and nuclear magnetic resonance spectroscopy. Findings and conclusions. Stable, water-soluble CdSe nanoparticles were synthesized with narrow size distribution. Changing the ratio of metal to chalcogen during the synthesis could easily control the sizes of the nanocolloids formed. In2S3 nanoparticles were synthesized with a variety of stabilizer molecules. These particles also showed strong luminescence, which had not been reported for these materials. The surface modification of CdSe and In2S3 nanoparticles with the ruthenium complex resulted in the formation of new bands from the electronic states of the nanoparticles and the complex. The lifetime of emission increased with the modification reaction. There was due to the formation of delocalized energy levels as a consequence of modification reaction.

  15. Direct Synthesis of Novel and Reactive Sulfide-modified Nano Iron through Nanoparticle Seeding for Improved Cadmium-Contaminated Water Treatment

    Science.gov (United States)

    Su, Yiming; Adeleye, Adeyemi S.; Huang, Yuxiong; Zhou, Xuefei; Keller, Arturo A.; Zhang, Yalei

    2016-04-01

    Magnetic sulfide-modified nanoscale zerovalent iron (S-nZVI) is of great technical and scientific interest because of its promising application in groundwater remediation, although its synthesis is still a challenge. We develop a new nanoparticle seeding method to obtain a novel and reactive nanohybrid, which contains an Fe(0) core covered by a highly sulfidized layer under high extent of sulfidation. Syntheses monitoring experiments show that seeding accelerates the reduction rate from Fe2+ to Fe0 by 19%. X-ray adsorption near edge structure (XANES) spectroscopy and extended X-ray absorption fine structure analyses demonstrate the hexahedral Fe-Fe bond (2.45 and 2.83 Å) formation through breaking down of the 1.99 Å Fe-O bond both in crystalline and amorphous iron oxide. The XANES analysis also shows 24.2% (wt%) of FeS with bond length of 2.4 Å in final nanohybrid. Both X-ray diffraction and Mössbauer analyses further confirm that increased nanoparticle seeding results in formation of more Fe0 crystals. Nano-SiO2 seeding brings down the size of single Fe0 grain from 32.4 nm to 18.7 nm, enhances final Fe0 content from 5.9% to 55.6%, and increases magnetization from 4.7 to 65.5 emu/g. The synthesized nanohybrid has high cadmium removal capacity and holds promising prospects for treatment of metal-contaminated water.

  16. Patterns of Macroinvertebrate and Fish Diversity in Freshwater Sulphide Springs

    Directory of Open Access Journals (Sweden)

    Ryan Greenway

    2014-09-01

    Full Text Available Extreme environments are characterised by the presence of physicochemical stressors and provide unique study systems to address problems in evolutionary ecology research. Sulphide springs provide an example of extreme freshwater environments; because hydrogen sulphide’s adverse physiological effects induce mortality in metazoans even at micromolar concentrations. Sulphide springs occur worldwide, but while microbial communities in sulphide springs have received broad attention, little is known about macroinvertebrates and fish inhabiting these toxic environments. We reviewed qualitative occurrence records of sulphide spring faunas on a global scale and present a quantitative case study comparing diversity patterns in sulphidic and adjacent non-sulphidic habitats across replicated river drainages in Southern Mexico. While detailed studies in most regions of the world remain scarce, available data suggests that sulphide spring faunas are characterised by low species richness. Dipterans (among macroinvertebrates and cyprinodontiforms (among fishes appear to dominate the communities in these habitats. At least in fish, there is evidence for the presence of highly endemic species and populations exclusively inhabiting sulphide springs. We provide a detailed discussion of traits that might predispose certain taxonomic groups to colonize sulphide springs, how colonizers subsequently adapt to cope with sulphide toxicity, and how adaptation may be linked to speciation processes.

  17. Identification, characterization and expression profiles of Chironomus riparius glutathione S-transferase (GST) genes in response to cadmium and silver nanoparticles exposure

    Energy Technology Data Exchange (ETDEWEB)

    Nair, Prakash M. Gopalakrishnan [School of Environmental Engineering and Graduate School of Energy and Environmental System Engineering, University of Seoul, 90 Jeonnong-dong, Dongdaemun-gu, Seoul 130-743 (Korea, Republic of); Choi, Jinhee, E-mail: jinhchoi@uos.ac.kr [School of Environmental Engineering and Graduate School of Energy and Environmental System Engineering, University of Seoul, 90 Jeonnong-dong, Dongdaemun-gu, Seoul 130-743 (Korea, Republic of)

    2011-02-15

    In this study, we report the identification and characterization of 13 cytosolic GST genes in Chironomus riparius from Expressed Sequence Tags (ESTs) database generated using pyrosequencing. Comparative and phylogenetic analyses were undertaken with Drosophila melanogaster and Anopheles gambiae GSTs and 3 Delta, 4 Sigma, 1 each in Omega, Epsilon, Theta, Zeta and 2 unclassified classes of GSTs were identified and characterized. The relative mRNA expression levels of all of the C. riparius GSTs (CrGSTs) genes under different developmental stages were varied with low expression in the larval stage. The antioxidant role of CrGSTs was studied by exposing fourth instar larvae to a known oxidative stress inducer Paraquat and the relative mRNA expression to different concentrations of cadmium (Cd) and silver nanoparticles (AgNPs) for various time intervals were also studied. All the CrGSTs showed up- or down regulation to varying levels based upon the concentration, and duration of exposure. The highest mRNA expression was noticed in Delta3, Sigma4 and Epsilon1 GST class in all treatments. These results show the role of CrGST genes in defense against oxidative stress and its potential as a biomarker to Cd and AgNPs exposure.

  18. Investigation of the explosion hazards of hydrogen sulphide

    International Nuclear Information System (INIS)

    The results of Phase I of an investigation directed towards quantifying the explosion hazards of hydrogen sulphide in air are described. The first phase is focussed on detonation in free hydrogen sulphide/air clouds. Detonation properties, including velocity and pressure, have been calculated and compared with experimental results. The observed detonation structure together with critical tube tests tests are used to assess the detonability of hydrogen sulphide/air mixtures relative to hydrogen and common hydrocarbon gases. Detailed chemical kinetic modelling of hydrogen sulphide combustion in air has been performed to correlate the detonation cell size data and to determine the influence of water vapour on the detonability of hydrogen sulphide in air. Calculations of the blast wave properties for detonation of a hydrogen sulphide/air cloud provide the data required to assess the blast effects of such explosions

  19. The endogenous production of hydrogen sulphide in intrauterine tissues

    Directory of Open Access Journals (Sweden)

    Wang Rui

    2009-02-01

    Full Text Available Abstract Background Hydrogen sulphide is a gas signalling molecule which is produced endogenously from L-cysteine via the enzymes cystathionine beta-synthase (CBS and cystathionine gamma-lyase (CSE. The possible role of hydrogen sulphide in reproduction has not yet been fully investigated. It has been previously demonstrated that hydrogen sulphide relaxes uterine smooth muscle in vitro. The aim of the present study was to investigate the endogenous production of hydrogen sulphide in rat and human intrauterine tissues in vitro. Methods The production of hydrogen sulphide in rat and human intrauterine tissues was measured in vitro using a standard technique. The expression of CBS and CSE was also investigated in rat and human intrauterine tissues via Western blotting. Furthermore, the effects of nitric oxide (NO and low oxygen conditions on the production rates of hydrogen sulphide were investigated. Results The order of hydrogen sulphide production rates (mean +/- SD, n = 4 for rat tissues were: liver (777 +/- 163 nM/min/g > uterus (168 +/- 100 nM/min/g > fetal membranes (22.3 +/- 15.0 nM/min/g > placenta (11.1 +/- 4.7 nM/min/g, compared to human placenta (200 +/- 102 nM/min/g. NO significantly increased hydrogen sulphide production in rat fetal membranes (P Conclusion Rat and human intrauterine tissues produce hydrogen sulphide in vitro possibly via CBS and CSE enzymes. NO increased the production of hydrogen sulphide in rat fetal membranes. The augmentation of hydrogen sulphide production in human intrauterine tissues in a low oxygen environment could have a role in pathophysiology of pregnancy.

  20. Dielectric properties of CdS nanoparticles synthesized by soft chemical route

    Indian Academy of Sciences (India)

    R Tripathi; A Kumar; T P Sinha

    2009-06-01

    CdS nanoparticles have been synthesized by a chemical reaction route using thiophenol as a capping agent. The frequency-dependent dielectric dispersion of cadmium sulphide (CdS) is investigated in the temperature range of 303–413 K and in a frequency range of 50 Hz–1 MHz by impedance spectroscopy. An analysis of the complex permittivity (′ and ″) and loss tangent (tan ) with frequency is performed by assuming a distribution of relaxation times. The scaling behaviour of dielectric loss spectra suggests that the relaxation describes the same mechanism at various temperatures. The frequency-dependent electrical data are analysed in the framework of conductivity and modulus formalisms. The frequency-dependent conductivity spectra obey the power law.

  1. Electrochemical mechanism of thioglycolic acid depressing sulphide minerals

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effects of thioglycolic acid (TGA) on the rest potential and zeta potential of sulphide minerals were studied and the electrochemical mechanism of TGA depressing sulphide minerals was put forward. Results of flotation test show that galena, pyrite and chalcopyrite can be well depressed by TGA, but sphalerite and arsenopyrite can not be depressed. Tests also show that TGA has a little influence on zeta potential of sulfide minerals covered by xanthate coatings and TGA can lower the rest potential of sulphide minerals. The electrochemical mechanism of TGA depressing sulphide minerals is that the dixanthogen adsorbing on the mineral surface will be unstable and reduced when rest potential value of sulphide mineral (φMS) is less than the reversible potential of reduction of dixanthogen to xanthate φX-|X2 in the presence of TGA, flotability of sulphide mineral becomes weak; inversely, the coatings of dixanthogen on mineral surface will keep stable when φMS>φX-|X2, sulphide mineral keeps flotability. In the system of mixed minerals, the electrochemical condition of separation of two sulphide minerals by TGA is φMS1<φX-|X2(φX-|PbX2)<φMS2.

  2. Copper variation in Cu(In,Ga)Se2 solar cells with indium sulphide buffer layer

    International Nuclear Information System (INIS)

    In the manufacturing of Cu(In,Ga)Se2 (CIGS) thin film solar cells the application of a buffer layer on top of the absorber is essential to obtain high efficiency devices. Regarding the roll-to-roll production of CIGS cells and modules a vacuum deposition process for the buffer is preferable to the conventional cadmium sulphide buffer deposited in a chemical bath. Promising results have already been achieved for the deposition of indium sulphide buffer by different vacuum techniques. The solar device performance is very sensitive to the conditions at the absorber-buffer heterojunction. In view of optimization we investigated the influence of the Cu content in the absorber on the current-voltage characteristics. In this work the integral copper content was varied between 19 and 23 at.% in CIGS on glass substrates. An improvement of the cell performance by enhanced open circuit voltage was observed for a reduction to ~ 21 at.% when thermally evaporated indium sulphide was applied as the buffer layer. The influence of stoichiometry deviations on the transport mechanism and secondary barriers in the device was studied using detailed dark and light current-voltage analysis and admittance spectroscopy and compared to the reference CdS-buffered cells. We conclude that the composition of the absorber in the interface region affects current transport in InxSy-buffered and CdS-buffered cells in different ways hence optimal Cu content in those two types of devices is different. - Highlights: • Influence of Cu-variation in CIGS cells with InxSy buffer layer on cell performance • Enhanced efficiency by slight reduction of Cu-content to 21 at.% • Contribution of tunnelling-enhanced interface recombination for higher Cu-content

  3. Prediction of sulphide build-up in filled sewer pipes.

    Science.gov (United States)

    Alani, Amir M; Faramarzi, Asaad; Mahmoodian, Mojtaba; Tee, Kong Fah

    2014-08-01

    Millions of dollars are being spent worldwide on the repair and maintenance of sewer networks and wastewater treatment plants. The production and emission of hydrogen sulphide has been identified as a major cause of corrosion and odour problems in sewer networks. Accurate prediction of sulphide build-up in a sewer system helps engineers and asset managers to appropriately formulate strategies for optimal sewer management and reliability analysis. This paper presents a novel methodology to model and predict the sulphide build-up for steady state condition in filled sewer pipes. The proposed model is developed using a novel data-driven technique called evolutionary polynomial regression (EPR) and it involves the most effective parameters in the sulphide build-up problem. EPR is a hybrid technique, combining genetic algorithm and least square. It is shown that the proposed model can provide a better prediction for the sulphide build-up as compared with conventional models. PMID:24956763

  4. On-line Ultrasound-Assisted Dispersive Micro-Solid-Phase Extraction Based on Amino Bimodal Mesoporous Silica Nanoparticles for the Preconcentration and Determination of Cadmium in Human Biological Samples.

    Science.gov (United States)

    Shirkhanloo, H; Falahnejad, M; Zavvar Mousavi, H

    2016-06-01

    On-line ultrasound-assisted dispersive micro-solid-phase extraction (USA-DμSPE) has been developed for preconcentration and separation of trace amounts of Cd(II) ions in 0.5 mL of human biological samples. In a syringe with a nylon membrane, new synthetic bulky amino bimodal mesoporous silica nanoparticles (NH2-UVM7) were dispersed as a nanoadsorbent in 5 mL of diluted serum sample (1:10), and after ultrasonic shaking, the liquid phase was separated from the solid phase. At the optimized pH, the chemical and physical adsorption of cadmium ions occurred, respectively, based on complexation with amine groups of UVM7 (Cd:NH2-UVM7) and silica nanoparticles. The analyte was then back-extracted from the sorbent with nitric acid solution (0.2 M), and its concentration was determined by electrothermal atomic absorption spectrometry (ETAAS). Under the optimized conditions, the linear range, limit of detection (LOD), and preconcentration factor (PF) were obtained as 0.01-0.56 μg L(-1), 0.002 μg L(-1), and 25, respectively. The adsorption capacity of NH2-UVM7 was found to be 108.6 mg g(-1) of cadmium. The validation of the methodology was performed by the human standard reference material (HSRM). PMID:26475301

  5. Synthesis and characterization of bismuth doped barium sulphide nanoparticles

    International Nuclear Information System (INIS)

    We have synthesized BaS:Bi nanocrystalline powder of average grain size 35 nm by solid-state diffusion method using sodium thiosulphate as a flux. During this work we have optimized the nature and amount of flux, amount of the dopant and temperature of firing for maximum yield of photoluminescence. The samples were characterized by X-ray powder diffraction (XRD) method, transmission electron microscopy (TEM), photoluminescence (PL) and UV-visible techniques. On excitation by 425 nm, these nanophosphors give one emission peak at 575 nm which corresponds to green color. In the excitation spectra of these particles there are two peaks at 350 nm and 425 nm. The effect of dopant concentration on the photoluminescence of BaS:Bi nanocrystallites has been studied which is in agreement with the principle of concentration quenching. The energy band gap of bismuth doped BaS nanopowder has been calculated to be 4.25 eV and is blue shifted in comparison to their bulk counterparts. The blue shift may be due to the quantum confinement in the particles.

  6. Deposition of carbonyl sulphide to soils

    Science.gov (United States)

    Kluczewski, S. M.; Brown, K. A.; Bel, J. N. B.

    Carbonyl sulphide (COS) is a trace constituent of the atmosphere and is also the main form in which 35S is released from CO 2-cooled nuclear reactors. Measurements of its deposition velocity ( Vg) are therefore important for validating radiological dose models and for interpreting the role of COS in the global S cycle. The Vg of [ 35S]COS to thin layers of several contrasting soils was measured in a through-flow fumigation system. Deposition velocity was not significantly affected by soil type, although deposition to moist soil was significantly greater ( P dried soils, mean values being 5.71 × 10 -6 ms -1 and 3.06 × 10 -6 ms -1, respectively. The results obtained are about three orders of magnitude smaller than published Vg values for SO 2 to similar soils, which suggests that uptake by soils is not a major sink for atmospheric COS. The results are consistent with the hypothesis that deposition to soil of [ 35S]COS from nuclear reactors is unlikely to contribute significantly to radiation dose from the food chain pathway. The reduction in Vg observed in heat-treated soils indicates a microbial involvement in uptake. However, it seems unlikely that microbial metabolism is the rate-controlling step, since stimulation of the microflora by the addition of nutrients did not increase COS deposition.

  7. Sulphide fluxes and concentrations in the spent nuclear fuel repository at Olkiluoto

    International Nuclear Information System (INIS)

    Sulphide may act as corrodant for the copper canister in the KBS-3 disposal concept. Sulphide fluxes at repository level are affected by various sources in the host rock, the backfill and the buffer. Hydrogen sulphide is effectively immobilised by Fe to form insoluble iron sulphide minerals. Thus, dissolved sulphide levels in reducing environment and also in Olkiluoto groundwaters are generally low. In zones favourable for sulphate reducing bacteria (SRB), however, temporarily more elevated sulphide concentrations are possible. The sulphate reduction and subsequent iron sulphide precipitation process depends on geochemical conditions, microbial activity and mass transfer of the reactants and is thus highly system-specific. The overall objective of the work presented in this report is to provide a thorough background for the sulphide concentrations and sulphide fluxes in the near field and the far field used in the performance assessment 2012

  8. SR-Site - sulphide content in the groundwater at Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Tullborg, E-L (Terralogica (Sweden)); Smellie, J (Conterra (Sweden)); Nilsson, A-Ch (Geosigma (Sweden)); Gimeno, M J; Auque, LF (Univ. of Zaragoza (Spain)); Bruchert, V (Stockholms Universitet (Sweden)); Molinero, J (Amphos21 (Spain))

    2010-12-15

    Sulphide concentrations in groundwater play a key role in the long-term reliability of the metal canisters containing the radioactive waste within a disposal facility for nuclear waste. This is because sulphide in the groundwaters circulating in the vicinity of the deposition tunnels can react with copper in the canisters causing corrosion and therefore reducing their expected lifetime; in a worst case scenario erosion of the bentonite buffer material will expose the canister more rapidly to the fracture groundwater.Sulphide in the groundwater is predominantly microbially produced and thereby controlled by the content of oxidised sulphur sources, organics (carbon sources), reductants (mainly Fe(II), DOC, H{sub 2} and CH{sub 4}), and also flow and mixing of different groundwater types. In addition, achieved saturation in respect to amorphous Fe-monosulphide will control the possible maximum values and will also limit the Fe2+ and S2- values in the groundwater. The aim of this report is to assess realistic, representative and reliable sulphide groundwater concentrations at present conditions in Forsmark and also to evaluate possible changes during different climatic conditions covering the repository operation period (some tens to hundreds of years), post closure conditions (some thousand of years) and the proceeding temperate period (some tens of thousands of years) which may be extended due to enhanced greenhouse effects etc. It is expected that this period will be followed by the onset of the next glaciation during which periglacial (permafrost), glacial and postglacial conditions may succeed each other. To achieve these aims, an evaluation is performed of all the sulphide-related data reported from the Forsmark site investigations /Laaksoharju et al. 2008/ and later monitoring campaigns, all of which are stored in the Sicada database. This evaluation shows that values from the Complete Chemical Characterisation (CCC) sampling are usually lower than those measured

  9. SR-Site - sulphide content in the groundwater at Forsmark

    International Nuclear Information System (INIS)

    Sulphide concentrations in groundwater play a key role in the long-term reliability of the metal canisters containing the radioactive waste within a disposal facility for nuclear waste. This is because sulphide in the groundwaters circulating in the vicinity of the deposition tunnels can react with copper in the canisters causing corrosion and therefore reducing their expected lifetime; in a worst case scenario erosion of the bentonite buffer material will expose the canister more rapidly to the fracture groundwater.Sulphide in the groundwater is predominantly microbially produced and thereby controlled by the content of oxidised sulphur sources, organics (carbon sources), reductants (mainly Fe(II), DOC, H2 and CH4), and also flow and mixing of different groundwater types. In addition, achieved saturation in respect to amorphous Fe-monosulphide will control the possible maximum values and will also limit the Fe2+ and S2- values in the groundwater. The aim of this report is to assess realistic, representative and reliable sulphide groundwater concentrations at present conditions in Forsmark and also to evaluate possible changes during different climatic conditions covering the repository operation period (some tens to hundreds of years), post closure conditions (some thousand of years) and the proceeding temperate period (some tens of thousands of years) which may be extended due to enhanced greenhouse effects etc. It is expected that this period will be followed by the onset of the next glaciation during which periglacial (permafrost), glacial and postglacial conditions may succeed each other. To achieve these aims, an evaluation is performed of all the sulphide-related data reported from the Forsmark site investigations /Laaksoharju et al. 2008/ and later monitoring campaigns, all of which are stored in the Sicada database. This evaluation shows that values from the Complete Chemical Characterisation (CCC) sampling are usually lower than those measured during the

  10. Corrosion of copper alloys in sulphide containing district heting systems

    DEFF Research Database (Denmark)

    Thorarinsdottir, R.I.; Maahn, Ernst Emanuel

    1999-01-01

    Copper and some copper alloys are prone to corrosion in sulphide containing geothermal water analogous to corrosion observed in district heating systems containing sulphide due to sulphate reducing bacteria. In order to study the corrosion of copper alloys under practical conditions a test...... was carried out at four sites in the Reykjavik District Heating System. The geothermal water chemistry is different at each site. The corrosion rate and the amount and chemical composition of deposits on weight loss coupons of six different copper alloys are described after exposure of 12 and 18 months...

  11. Ultrafine milling for the processing of gold-bearing sulphides

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Ultrafine milling technology is used to treat gold-bearing sulphides and to investigate the effects of minerals size, milling time, liquid/solid ratio, NaCN consumption and leaching aid on leaching rate of gold. The results indicate that shorter treating time, decrease of NaCN consumption of 60% and increase of gold leaching rate of 15% can be obtained by the ultrafine milling technology compared with traditional cyanide leaching. Potential exists for the new process to form the basis for an economically viable, high-efficiency process for treatment of gold-bearing sulphides.

  12. Copper variation in Cu(In,Ga)Se{sub 2} solar cells with indium sulphide buffer layer

    Energy Technology Data Exchange (ETDEWEB)

    Spiering, S., E-mail: stefanie.spiering@zsw-bw.de [Zentrum für Sonnenenergie- und Wasserstoff-Forschung (ZSW) Baden-Wuerttemberg, Industriestrasse 6, 70565 Stuttgart (Germany); Paetel, S.; Kessler, F. [Zentrum für Sonnenenergie- und Wasserstoff-Forschung (ZSW) Baden-Wuerttemberg, Industriestrasse 6, 70565 Stuttgart (Germany); Igalson, M.; Abdel Maksoud, H. [Warsaw University of Technology (WUT), Faculty of Physics, Koszykowa 75, 00-662 Warszawa (Poland)

    2015-05-01

    In the manufacturing of Cu(In,Ga)Se{sub 2} (CIGS) thin film solar cells the application of a buffer layer on top of the absorber is essential to obtain high efficiency devices. Regarding the roll-to-roll production of CIGS cells and modules a vacuum deposition process for the buffer is preferable to the conventional cadmium sulphide buffer deposited in a chemical bath. Promising results have already been achieved for the deposition of indium sulphide buffer by different vacuum techniques. The solar device performance is very sensitive to the conditions at the absorber-buffer heterojunction. In view of optimization we investigated the influence of the Cu content in the absorber on the current-voltage characteristics. In this work the integral copper content was varied between 19 and 23 at.% in CIGS on glass substrates. An improvement of the cell performance by enhanced open circuit voltage was observed for a reduction to ~ 21 at.% when thermally evaporated indium sulphide was applied as the buffer layer. The influence of stoichiometry deviations on the transport mechanism and secondary barriers in the device was studied using detailed dark and light current-voltage analysis and admittance spectroscopy and compared to the reference CdS-buffered cells. We conclude that the composition of the absorber in the interface region affects current transport in In{sub x}S{sub y}-buffered and CdS-buffered cells in different ways hence optimal Cu content in those two types of devices is different. - Highlights: • Influence of Cu-variation in CIGS cells with In{sub x}S{sub y} buffer layer on cell performance • Enhanced efficiency by slight reduction of Cu-content to 21 at.% • Contribution of tunnelling-enhanced interface recombination for higher Cu-content.

  13. Surface Passivation of Mercury-Cadmium-Telluride Infrared Detectors

    Directory of Open Access Journals (Sweden)

    R. Singh

    1991-07-01

    Full Text Available The theoretical considerations and practical aspects of passivating insulator films, in the context of their use on high-performance mercury cadmium telluride (MCT infrared detectors are reviewed. The methods of growth, the interface properties and the applications of both native and deposited passivant films have been discussed. Native films include anodic, chemical, photochemical, and plasma oxides as well as anodic sulphides and fluoro-oxides. Deposited films include ZnS, photo-CVD-grown SiO2, CDTe, and SiN/sub x/. The properties of all these passivant films on MCT have been summarized.

  14. SR-Site - sulphide content in the groundwater at Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Tullborg, E-L (Terralogica, Graabo (Sweden)); Smellie, J. (Conterra, Uppsala (Sweden)); Nilsson, A-Ch (Geosigma, Uppsala (Sweden)); Gimeno, M.J.; Auque, L.F. (Univ. of Zaragoza (Spain)); Wallin, B. (Geokema, Lidingoe (Sweden)); Bruechert, V. (Stockholm Univ. (Sweden)); Molinero, J. (Amphos21, Barcelona (Spain))

    2010-12-15

    Sulphide concentrations in groundwater play a key role in the long term reliability of the metal canisters containing the radioactive waste within a disposal facility for nuclear waste. This is because sulphide in the groundwaters circulating in the vicinity of the deposition tunnels can react with copper in the canisters causing corrosion and therefore reducing their expected lifetime; in a worst case scenario erosion of the bentonite buffer material will expose the canister more rapidly to the fracture groundwater. Sulphide in the groundwater is predominantly microbially produced and thereby controlled by the content of oxidised sulphur sources, organics (carbon sources), reductants (mainly Fe(II), DOC, H{sub 2} and CH{sub 4}), and also flow. In addition, achieved saturation in respect to amorphous Fe-monosulphide will control the possible maximum values and thus limit the Fe2+ and S2- values in the groundwater. The aim of this report is to assess realistic, representative and reliable sulphide groundwater concentrations at present conditions in Laxemar to be considered for use in (future) safety assessments. To achieve this, an evaluation is performed of all the sulphide related data reported from the Laxemar site investigations /Laaksoharju et al. 2009/ and later monitoring campaigns, all of which are stored in the Sicada database. This evaluation shows that values from the Complete Chemical Characterisation (CCC) (i.e. in situ sampling from one or more borehole sections using mobile equipment) are usually lower than those measured during the monitoring phase (i.e. in situ sampling from one borehole section using permanently installed equipment). An exception is borehole KLX01, where values generally lie within the same range as the monitoring samples. For most of the CCC and monitoring sections the last sample in the time series is suggested as representing the 'best possible' sulphide value. When both initial values from CCC (or samples taken with

  15. SR-Site - sulphide content in the groundwater at Laxemar

    International Nuclear Information System (INIS)

    Sulphide concentrations in groundwater play a key role in the long term reliability of the metal canisters containing the radioactive waste within a disposal facility for nuclear waste. This is because sulphide in the groundwaters circulating in the vicinity of the deposition tunnels can react with copper in the canisters causing corrosion and therefore reducing their expected lifetime; in a worst case scenario erosion of the bentonite buffer material will expose the canister more rapidly to the fracture groundwater. Sulphide in the groundwater is predominantly microbially produced and thereby controlled by the content of oxidised sulphur sources, organics (carbon sources), reductants (mainly Fe(II), DOC, H2 and CH4), and also flow. In addition, achieved saturation in respect to amorphous Fe-monosulphide will control the possible maximum values and thus limit the Fe2+ and S2- values in the groundwater. The aim of this report is to assess realistic, representative and reliable sulphide groundwater concentrations at present conditions in Laxemar to be considered for use in (future) safety assessments. To achieve this, an evaluation is performed of all the sulphide related data reported from the Laxemar site investigations /Laaksoharju et al. 2009/ and later monitoring campaigns, all of which are stored in the Sicada database. This evaluation shows that values from the Complete Chemical Characterisation (CCC) (i.e. in situ sampling from one or more borehole sections using mobile equipment) are usually lower than those measured during the monitoring phase (i.e. in situ sampling from one borehole section using permanently installed equipment). An exception is borehole KLX01, where values generally lie within the same range as the monitoring samples. For most of the CCC and monitoring sections the last sample in the time series is suggested as representing the 'best possible' sulphide value. When both initial values from CCC (or samples taken with the hydrotest equipment

  16. An easy shortcut synthesis of size-controlled bismuth nanoparticles and their use in the SLS growth of high-quality colloidal cadmium selenide quantum wires.

    Science.gov (United States)

    Wang, Fudong; Buhro, William E

    2010-02-22

    An easy shortcut synthesis of thermally stable, near-monodisperse Bi nanoparticles from BiCl(3) and Na[N(SiMe(3))(2)] is described. The diameters of the Bi nanoparticles are controlled in the range of 4-29 nm by varying the amounts of BiCl(3) and Na[N(SiMe(3))(2)] employed. Standard deviations in their diameter distributions are 5-15% of the mean diameters, consistent with near monodispersity. These Bi nanoparticles are shown to be the best currently available catalysts for the solution-liquid-solid (SLS) growth of high-quality CdSe quantum wires.

  17. Tolerance of benthic foraminifera (Protista : Sarcodina) to hydrogen sulphide

    NARCIS (Netherlands)

    Moodley, L.; Schaub, B.; Van der Zwaan, G.J.; Herman, P.M.J.

    1998-01-01

    Benthic foraminifera are dominant members of tb meiofauna, commonly occurring below the anoxic-oxic interface in marine sediments. The absence of oxygen in marine coastal sediments is often correlated with the formation of hydrogen sulphide. In this study the tolerance of benthic foraminifera (from

  18. nanoparticles

    Science.gov (United States)

    Andreu-Cabedo, Patricia; Mondragon, Rosa; Hernandez, Leonor; Martinez-Cuenca, Raul; Cabedo, Luis; Julia, J. Enrique

    2014-10-01

    Thermal energy storage (TES) is extremely important in concentrated solar power (CSP) plants since it represents the main difference and advantage of CSP plants with respect to other renewable energy sources such as wind, photovoltaic, etc. CSP represents a low-carbon emission renewable source of energy, and TES allows CSP plants to have energy availability and dispatchability using available industrial technologies. Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 500°C. Their main drawbacks are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve thermal properties of fluids is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. In this work, solar salt used in CSP plants (60% NaNO3 + 40% KNO3) was doped with silica nanoparticles at different solid mass concentrations (from 0.5% to 2%). Specific heat was measured by means of differential scanning calorimetry (DSC). A maximum increase of 25.03% was found at an optimal concentration of 1 wt.% of nanoparticles. The size distribution of nanoparticle clusters present in the salt at each concentration was evaluated by means of scanning electron microscopy (SEM) and image processing, as well as by means of dynamic light scattering (DLS). The cluster size and the specific surface available depended on the solid content, and a relationship between the specific heat increment and the available particle surface area was obtained. It was proved that the mechanism involved in the specific heat increment is based on a surface phenomenon. Stability of samples was tested for several thermal cycles and thermogravimetric analysis at high temperature was carried out, the samples being stable.

  19. Synthesis and characterization of Sn-doped CdZnS nanoparticles

    Indian Academy of Sciences (India)

    R Shrivastava; S C Shrivastava

    2015-09-01

    Tin (Sn)-doped cadmium zinc sulphide nanoparticles (CdZnS : Sn) were synthesized by the chemical bath deposition method with two different concentrations of Sn (2 and 4 mol%). X-ray diffraction (XRD) pattern reveals the formation of CdZnS nanoparticles with cubic and hexagonal structure. It was observed that the presence of Sn does not alter the structure of CdZnS. Average crystallite size was measured from XRD data by using Scherrer’s formula. From the study of absorption spectra, band-to-band absorption was obtained at 460 and 490 nm, respectively, for the Sn-doped (2 and 4 mol%) CdZnS nanoparticles. Energy bandgap for undoped and Sn-doped CdZnS varies from 3.5 to 2.9 eV with error ± 0.05 eV. The presence of Sn was confirmed by energy-dispersive X-ray analysis. The effect of dopant concentration on the photoluminescence (PL) intensity has also been studied. The PL emission peak has been observed at 540, 550 and 560 nm for the Sn-doped (CdZnS, CdZnS 2 mol% and CdZnS 4 mol%), respectively, nanoparticles. XRD and PL analyses demonstrate that the Sn2+ ions uniformly substitute Cd2+ sites or interstitial sites in CdZnS lattice, which influence the optical properties. Increase in the concentration of Sn shifts the UV–vis absorption spectra and PL emission spectra towards higher wavelength side. Particle size and the crystallinity of CdZnS : Sn nanoparticles were confirmed through atomic force microscopy.

  20. Photocatalytic and antibacterial activity of cadmium sulphide/zinc oxide nanocomposite with varied morphology.

    Science.gov (United States)

    Jana, T K; Maji, S K; Pal, A; Maiti, R P; Dolai, T K; Chatterjee, K

    2016-10-15

    Nanocomposites with multifunctional application prospects have already dragged accelerating interests of materials scientists. Here we present CdS/ZnO nanocomposites with different morphology engineering the precursor molar ratio in a facile wet chemical synthesis route. The materials were structurally and morphologically characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX) and high-resolution transmission electron microscopy (HRTEM). The growth mechanism of the composite structure with varying molar ratio is delineated with oriented attachment self assemble techniques. Photocatalytic activity of CdS/ZnO nanocomposites with varying morphology were explored for the degradation of rhodamine B (RhB) dye in presence of visible light irradiation and the results reveal that the best catalytic performance arises in CdS/ZnO composite with 1: 1 ratio. The antibacterial efficiency of all nanocomposites were investigated on Escherichia coli, Staphylococcus aureus and Klebsiella pneumonia without light irradiation. Antibacterial activity of CdS/ZnO nanocomposites were studied using the bacteriological test-well diffusion agar method and results showed significant antibacterial activity in CdS/ZnO composite with 1:3 ratio. Overall, CdS/ZnO nanocomposites excel in different potential applications, such as visible light photocatalysis and antimicrobial activity with their tuneable structure. PMID:27399614

  1. Determination of boron, silica, fluoride, MBAS, phenols, cyanide and sulphide

    International Nuclear Information System (INIS)

    This study forms part of the NIWR's series of interlaboratory comparison studies involving southern African laboratories engaged in water and wastewater analysis, and is concerned with the analysis of synthetic water samples by 31 laboratories for boron, silica, fluoride, methylene blue active substances (MBAS), phenols, cyanide and sulphide. The results obtained are evaluated and discussed. Recognised standard methods, or modifications of these methods, were used for most of the determinations. Results from the boron, silica and fluoride determinations showed, in general, acceptable accuracy and precision. Results from the MBAS, phenols, cyanide and sulphide determinations were, however, somewhat widespread, and illustrated the difficulty in obtaining reliable results from the measurement of relatively low levels of these determinands

  2. Geological and geophysical characteristics of massive sulphide deposits: A case study of the Lirhanda massive sulphide deposit of Western Kenya

    Science.gov (United States)

    Dindi, E.; Maneno, J. B. J.

    2016-08-01

    An integrated geophysical ground survey was conducted on an airborne electromagnetic (EM) anomaly located in Kakamega forest of Western Kenya. The purpose of the study was to establish the existence of massive sulphides and identify suitable optimal geophysical method(s) for the investigation of similar anomalies. The study was also expected to provide information on the geological and geophysical characteristics of the deposit. Field work involved electromagnetic methods: Vertical Loop (VLEM), Horizontal Loop (HLEM), TURAM EM and potential field methods: gravity and magnetics. Geochemical sampling was carried out concurrently with the geophysical survey. All the geophysical methods used yielded good responses. Several conductors conforming to the strike of the geology were identified. TURAM EM provided a higher resolution of the conductors compared to VLEM and HLEM. The conductors were found to be associated with positive gravity anomalies supporting the presence of bodies of higher density than the horst rock. Only the western section (west of 625W) of the grid is associated with strong magnetic anomalies. East of 625W strong EM and gravity anomalies persist but magnetic anomalies are weak. This may reflect variation in the mineral composition of the conductors from magnetic to non-magnetic. Geochemical data indicates strong copper anomalies (upto 300 ppm) over sections of the grid and relatively strong zinc (upto 200 ppm) and lead (upto 100 ppm) anomalies. There is a positive correlation between the location of the conductors as predicted by TURAM EM and the copper and zinc anomalies. A test drill hole proposed on the basis of the geophysical results of this study struck massive sulphides at a depth of 30m still within the weathered rock zone. Unfortunately, the drilling was stopped before the sulphides could be penetrated. The drill core revealed massive sulphide rich in pyrite and pyrrhotite. An attempt has been made to compare characteristics of the Lirhanda

  3. Magnetic Characterization of Sulphide Ores: Examples From Sweden

    OpenAIRE

    Jirestig, J.; Forssberg, E.

    1992-01-01

    Diagrams of accumulativemagnetic susceptibility distribution are used to evaluate the suitability of four sulphide ores for magnetic methods of beneficiation. The investigated materials are Garpenberg, Aitik and Kedtrask. The samples were divided into susceptibility classes each of which was characterized by its mineral content. The results are presented as diagrams showing mineral appearance in the whole susceptibility range of the ore. The obtained accumulative susceptibility diagrams can b...

  4. Evolution of Acid Mine Drainage Formation in Sulphidic Mine Tailings

    OpenAIRE

    Bernhard Dold

    2014-01-01

    Sulphidic mine tailings are among the largest mining wastes on Earth and are prone to produce acid mine drainage (AMD). The formation of AMD is a sequence of complex biogeochemical and mineral dissolution processes. It can be classified in three main steps occurring from the operational phase of a tailings impoundment until the final appearance of AMD after operations ceased: (1) During the operational phase of a tailings impoundment the pH-Eh regime is normally alkaline to neutral and reduci...

  5. Tribological performance of organic cadmium compound as lubricant additive

    Institute of Scientific and Technical Information of China (English)

    HU Jian-qiang; XIE Feng; ZHU Huan-qin; ZHEN Fa-zheng; YAO Jun-bing

    2004-01-01

    The oil-soluble cadmium dipropyldithiophosphate additive was synthesized. A four-ball tester was used to evaluate the tribological performance of the additive in a mineral oil under different loads and lubricant grease synthesized compared with some commercial additives. The results show that it exhibits excellent antiwear and load-carrying capacities and is better than other additives. The surface analytical tools such as scanning electron microscope (SEM) with energy dispersive X-ray (EDX), X-ray photoelectron spectrometer (XPS) were used to investigate the topography, the compositions, and chemical states of some typical elements on the rubbing surface of worn scar.Smooth and light topography of worn scar further confirms that the additive shows good antiwear capacities. The results of EDX and XPS analyses indicate that tribochemical mixed protective films consisting of atomic cadmium, sulphides, sulphates and phosphates are formed on the rubbing surface, which contribute to improving the tribological properties of lubricant and grease. Particularly, the soft cadmium film formed plays an important role in improving antiwear properties of oils. Finally, antiwear mechanism of the additive and formation scheme of atomic cadmium was proposed.

  6. Leaching of complex sulphide concentrate in acidic cupric chloride solutions

    Institute of Scientific and Technical Information of China (English)

    M. TCHOUMOU; M. ROYNETTE

    2007-01-01

    The chemical analysis of a complex sulphide concentrate by emission spectrometry and X-ray diffraction shows that it contains essentially copper, lead, zinc and iron in the form of chalcopyrite, sphalerite and galena. A small amount of pyrite is also present in the ore but does not be detected with X-ray diffraction. The cupric chloride leaching of the sulphide concentrate at various durations and solid/liquid ratios at 100 ℃ shows that the rate of dissolution of the ore is the fastest in the first several hours, and after 12 h it does not evolve significantly. If oxygen is excluded from the aqueous cupric chloride solution during the leaching experiment at 100 ℃, the pyrite in the ore will not be leached. The determination of principal dissolved metals in the leaching liquor by flame atomic absorption spectrometry, and the chemical analysis of solid residues by emission spectrometry and X-ray diffraction allow to conclude that the rate of dissolution of the minerals contained in the complex sulphide concentrate are in the order of galena>sphalerite>chalcopyrite.

  7. A novel single-precursor nanoparticle growth technique for luminescent metal sulfides (cadmium sulfide, lead sulfide, zinc sulfide) with hydrophilic surface modification

    Science.gov (United States)

    Rama, Jason Eric

    In recent years luminescent semiconductor nanoparticles (quantum dots) have attracted considerable attention, mostly due to their size-dependent tunable spectroscopic properties. Currently, fluorescing particles are put to use as biological labels alongside, or even replacing, fluorescing molecular probes. They are characterized by very narrow and tunable (excitonic) emission bands and long-range stability even under illumination. In particular, the colloidal chemistry approach to luminescent nanoparticle fabrication has been favored due to its relative ease, and high size tunability. However, the development of highly monodisperse, size tunable, and highly stable aqueous colloidal suspension fabrication methodologies has to date been very limited. In this work, the synthesis of luminescent MS (M = Cd, Pb, Zn) nanoparticles was achieved through the development and implementation of three characteristically different reaction methodologies: a spontaneous precipitation reaction (the metal chloride method), a controlled precipitation reaction (the metal oxide method), and a novel controlled aqueous decomposition reaction (the metal ethyl xanthate method) in an alkylamine solvent of 4-dimethylaminopyridine (DMAP). Varying degrees of monodispersity were achieved for the various methods, as evidenced by the photoluminescence full-width at half-maximum (FWHM). Spectral widths range from 150 nm for spontaneous precipitation methods, to as small as 20 nm for each of the temperature-controlled nucleation and ripening methods. For each of the methods, attempts at size tunability through variation of precursor concentration, growth temperature and growth time were performed. This resulted in the demonstration of an ability to fabricate size-specified semiconducting nanoparticles in the sub-10 nm size range. A demonstration of aqueous-organic-aqueous phase transfer versatility of the metal ethyl xanthate-DMAP fabrication method advances the potential of this particular method

  8. Preparation of strongly fluorescent silica nanoparticles of polyelectrolyte-protected cadmium telluride quantum dots and their application to cell toxicity and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Tang Jianhua; Xie Lian; Zhang Bin; Qiu Ting [College of Pharmaceutical Science, Soochow University, Suzhou 215123 (China); Qi Bin [College of Pharmaceutical Science, Soochow University, Suzhou 215123 (China); College of Chemistry and Chemical Engineering, China West Normal University, Nangchong 637002 (China); Xie Hongping, E-mail: hpxie@suda.edu.cn [College of Pharmaceutical Science, Soochow University, Suzhou 215123 (China)

    2012-03-30

    Graphical abstract: The staining effect of the control group (a), QDs-SiO{sub 2} (b) and QDs-PDADMAC-SiO{sub 2}(c). Highlights: Black-Right-Pointing-Pointer The fluorescence intensity of QDs-PDADMAC-SiO{sub 2} is stronger than that of QDs-SiO{sub 2}. Black-Right-Pointing-Pointer The fluorescence stability of QDs-PDADMAC-SiO{sub 2} is better than that of QDs-SiO{sub 2}. Black-Right-Pointing-Pointer The cytotoxicity of QDs-PDADMAC-SiO{sub 2} was lower than that of QDs-SiO{sub 2} Black-Right-Pointing-Pointer The staining effect of QDs-PDADMAC-SiO{sub 2} was much better than that of QDs-SiO{sub 2}. - Abstract: Based on the polyelectrolyte-protected CdTe quantum dots (QDs), which were prepared by self-assembling of QDs and poly-diallyldimethylammonium chloride (PDADMAC) in the help of electrostatic attraction, the strong fluorescence silica nanoparticles (QDs-PDADMAC-SiO{sub 2}) have been prepared via a water-in-oil reverse microemulsion method. Transmission electron microscopy and Zeta potential analysis were used to characterize the as-prepared nanoparticles. All of the particles were almost spherical and there is a uniform distribution of the particle size with the average diameter about 25 nm. There is a large Zeta potential of -35.07 mV which is necessary for good monodispersity of nanoparticles solution. As compared with the QDs coated by SiO{sub 2} (QDs-SiO{sub 2}), the QDs-PDADMAC-SiO{sub 2} nanoparticles have much stronger fluorescence, and their fluorescence stability could be obviously improved. Moreover, QDs-PDADMAC-SiO{sub 2} exhibits good biological compatibility which promotes their application in cellular imaging.

  9. Effect of nitrocarburizing on sulphide layer during nitrocarburizing-sulphurating treatment

    Institute of Scientific and Technical Information of China (English)

    LI Xin; MA Shi-ning; LIU Ji-yan

    2005-01-01

    Compared with the single sulphurating treatment, the duplex treatment of nitrocarburizing-sulphurating can more effectively improve the properties of steel such as friction-reducing, wear resistance and anti-scuffing. Under the same processing parameters, the sulphide layers were fabricated on the surface of CrMoCu alloy cast iron by single ion-sulphurating treatment and nitrocarburizing-sulphurating duplex treatment, respectively. Through the analysis of the sulphide, the effect of the nitrocarburizing on the fabrication of the sulphide layer was investigated. And the result shows that the fabrication of sulphide layer is promoted by the nitrocarburizing treatment.

  10. Titanium Dioxide/Upconversion Nanoparticles/Cadmium Sulfide Nanofibers Enable Enhanced Full-Spectrum Absorption for Superior Solar Light Driven Photocatalysis.

    Science.gov (United States)

    Zhang, Fu; Zhang, Chuan-Ling; Wang, Wan-Ni; Cong, Huai-Ping; Qian, Hai-Sheng

    2016-06-22

    In this work, we demonstrate an electrospinning technique to fabricate TiO2 /upconversion nanoparticles (UCNPs)/CdS nanofibers on large scale. In addition, the as-prepared TiO2 nanofibers are incorporated with a high population of UCNPs and CdS nanospheres; this results in Förster resonance energy-transfer configurations of the UCNPs, TiO2 , and CdS nanospheres that are in close proximity. Hence, strong fluorescent emissions for the Tm(3+) ions including the (1) G4 →(3) H6 transition are efficiently transferred to TiO2 and the CdS nanoparticles through an energy-transfer process. The as-prepared TiO2 /UCNPs/CdS nanofibers exhibit full-spectrum solar-energy absorption and enable the efficient degradation of organic dyes by fluorescence resonance energy transfer between the UCNPs and TiO2 (or CdS). The UCNPs/TiO2 /CdS nanofibers may also have enhanced energy-transfer efficiency for wide applications in solar cells, bioimaging, photodynamics, and chemotherapy. PMID:27214754

  11. Titanium Dioxide/Upconversion Nanoparticles/Cadmium Sulfide Nanofibers Enable Enhanced Full-Spectrum Absorption for Superior Solar Light Driven Photocatalysis.

    Science.gov (United States)

    Zhang, Fu; Zhang, Chuan-Ling; Wang, Wan-Ni; Cong, Huai-Ping; Qian, Hai-Sheng

    2016-06-22

    In this work, we demonstrate an electrospinning technique to fabricate TiO2 /upconversion nanoparticles (UCNPs)/CdS nanofibers on large scale. In addition, the as-prepared TiO2 nanofibers are incorporated with a high population of UCNPs and CdS nanospheres; this results in Förster resonance energy-transfer configurations of the UCNPs, TiO2 , and CdS nanospheres that are in close proximity. Hence, strong fluorescent emissions for the Tm(3+) ions including the (1) G4 →(3) H6 transition are efficiently transferred to TiO2 and the CdS nanoparticles through an energy-transfer process. The as-prepared TiO2 /UCNPs/CdS nanofibers exhibit full-spectrum solar-energy absorption and enable the efficient degradation of organic dyes by fluorescence resonance energy transfer between the UCNPs and TiO2 (or CdS). The UCNPs/TiO2 /CdS nanofibers may also have enhanced energy-transfer efficiency for wide applications in solar cells, bioimaging, photodynamics, and chemotherapy.

  12. Cadmium toxicity and treatment.

    Science.gov (United States)

    Bernhoft, Robin A

    2013-01-01

    Cadmium is a heavy metal of considerable toxicity with destructive impact on most organ systems. It is widely distributed in humans, the chief sources of contamination being cigarette smoke, welding, and contaminated food and beverages. Toxic impacts are discussed and appear to be proportional to body burden of cadmium. Detoxification of cadmium with EDTA and other chelators is possible and has been shown to be therapeutically beneficial in humans and animals when done using established protocols.

  13. Cadmium Toxicity and Treatment

    Directory of Open Access Journals (Sweden)

    Robin A. Bernhoft

    2013-01-01

    Full Text Available Cadmium is a heavy metal of considerable toxicity with destructive impact on most organ systems. It is widely distributed in humans, the chief sources of contamination being cigarette smoke, welding, and contaminated food and beverages. Toxic impacts are discussed and appear to be proportional to body burden of cadmium. Detoxification of cadmium with EDTA and other chelators is possible and has been shown to be therapeutically beneficial in humans and animals when done using established protocols.

  14. Cadmium Toxicity and Treatment

    OpenAIRE

    Bernhoft, Robin A.

    2013-01-01

    Cadmium is a heavy metal of considerable toxicity with destructive impact on most organ systems. It is widely distributed in humans, the chief sources of contamination being cigarette smoke, welding, and contaminated food and beverages. Toxic impacts are discussed and appear to be proportional to body burden of cadmium. Detoxification of cadmium with EDTA and other chelators is possible and has been shown to be therapeutically beneficial in humans and animals when done using established proto...

  15. Prediction and optimisation of Pb/Zn/Fe sulphide scales in gas production fields

    Energy Technology Data Exchange (ETDEWEB)

    Dyer, Sarah; Orski, Karine; Menezes, Carlos; Heath, Steve; MacPherson, Calum; Simpson, Caroline; Graham, Gordon

    2006-03-15

    Lead, zinc and iron sulphide scales are known to be a particular issue with gas production fields, particularly those producing from HP/HT reservoirs. However the prediction of sulphide scale and the methodologies available for their laboratory assessment are not as well developed as those for the more conventional sulphate and carbonate scales. This work examines a particular sulphide scaling regime from a North Sea high temperature gas condensate production field containing only 0.8ppm of sulphide ions. Sulphide scales were identified in the production system which was shown to be a mixture of lead and zinc sulphide, primarily lead sulphide. This formed as a result of cooling during production resulting in the over saturation of these minerals. This paper describes scale prediction and modified laboratory test protocols used to re-create the scales formed in the field prior to chemical performance testing. From the brine composition, scale prediction identified that the major scales that could be formed were calcium carbonate, iron carbonate, iron sulphide, lead sulphide and zinc sulphide. In addition, modification of the brine compositions led to prediction of primarily one scale or the other. Given the predicted over saturation of various minerals, preliminary laboratory tests were therefore conducted in order to ensure that the scale formed under laboratory conditions was representative of the field scale. Laboratory protocols were therefore developed to ensure that the scales formed in fully anaerobic dynamic performance tests and static performance tests were similar to those encountered in the field. The paper compares results from field analysis, scale predictions and laboratory scale formation tests using newly developed test protocols and shows differences between prediction and laboratory data. The paper therefore demonstrates the importance of ensuring that the correct scale is formed under laboratory test conditions and also indicates some potential

  16. Fusion bonding of carbon fabric reinforced polyphenylene sulphide

    Directory of Open Access Journals (Sweden)

    Degrieck J.

    2010-06-01

    Full Text Available In recent years, there is a growing interest in joining techniques for thermoplastic composites as an alternative to adhesive bonding. In this manuscript, a fusion bonding process called hot-tool welding is investigated for this purpose and the used material is a carbon fabric reinforced polyphenylene sulphide. The quality of the welds is experimentally assessed using a short three-point bending setup, which has an interesting distribution of interlaminar shear stresses. It can be concluded that although the hot-tool welding process shows high short-beam strengths, it has some drawbacks. Therefore, a design of an infrared welding setup is presented.

  17. Spectroscopy of vanadium (III) doped gallium lanthanum sulphide chalcogenide glass

    CERN Document Server

    Hughes, M; Rutt, H; Hewak, D

    2014-01-01

    Vanadium doped gallium lanthanum sulphide glass (V:GLS) displays three absorption bands at 580, 730 and 1155 nm identified by photoluminescence excitation measurements. Broad photoluminescence, with a full width half maximum (FWHM) of 500 nm, is observed peaking at 1500 nm when exciting at 514, 808 and 1064 nm. The fluorescence lifetime and quantum efficiency at 300 K were measured to be 33.4 us and 4 % respectively. From the available spectroscopic data we propose the vanadium ions valence to be 3+ and be in tetrahedral coordination The results indicate potential for development of a laser or optical amplifier based on V:GLS.

  18. New exploration methods for platinum and rhodium deposits poor in base-metal sulphides

    DEFF Research Database (Denmark)

    Ohnenstetter, M.; Johan, Z.; Cocherie, A.;

    1999-01-01

    Platinum-group elements (PGE) are typically associated with mafic and ultramafic intrusive rocks and the main exploration targets are layers and zones rich in PGE-bearing sulphides. Some PGE occurences, however, are in sulphide-poor situations and this raises the possibility that PGE deposits may...

  19. 3D arrays of molybdenum sulphide nanosheets on Mo meshes: Efficient electrocatalysts for hydrogen evolution reaction

    International Nuclear Information System (INIS)

    3D arrays of molybdenum sulphide nanosheets on Mo mesh exhibited enhanced electro-catalytic activity for hydrogen evolution reaction. - Highlights: • 3D arrays of molybdenum sulphide nanosheets were obtained by a facile hydrothermal method. • The mesh structure could be beneficial to promote the electrolyte diffusion onto the electrode surface and thus promote the electron transfer. • 3D arrays of molybdenum sulphide nanosheets demonstrate an enhanced HER activity with a low onset overpotential of 120 mV and a Tafel slope of 46 mV/dec. - Abstract: Molybdenum sulphide has emerged as a promising electrocatalyst for hydrogen evolution reaction (HER). Toward further improving its activity, tremendous efforts have been made to preferentially expose active edge sites of molybdenum sulphide-based catalysts by engineering their surface structure. In this work, 3D arrays of molybdenum sulphide nanosheets were synthesized by hydrothermal treatment of Mo mesh in aqueous thiourea solution. Their compositional, morphological and structural properties as well as electrocatalytic activities were investigated in details. The results reveal that 3D arrays of molybdenum sulphide nanosheets demonstrate an enhanced HER activity with a low onset overpotential of 120 mV and a Tafel slope of 46 mV/dec, which is superior to that of 2D arrays molybdenum sulphide nanosheets grown on Mo foil. The high activity for HER can be ascribed to the superstructure of the catalysts with a large fraction of edge sites and a high surface area

  20. Allyl sulphides in olefin metathesis: catalyst considerations and traceless promotion of ring-closing metathesis.

    Science.gov (United States)

    Edwards, Grant A; Culp, Phillip A; Chalker, Justin M

    2015-01-11

    Allyl sulphides are reactive substrates in ruthenium-catalysed olefin metathesis reactions, provided each substrate is matched with a suitable catalyst. A profile of catalyst activity is described, along with the first demonstration of allyl sulphides as traceless promoters in relayed ring-closing metathesis reactions.

  1. New exploration methods for platinum and rhodium deposits poor in base-metal sulphides

    DEFF Research Database (Denmark)

    Ohnenstetter, M.; Johan, Z.; Cocherie, A.;

    1999-01-01

    -driven multistage mineralization concept suggested by field data. The experimental work also indicated that Pt-Rh-Fe alloys can coexist with two types of immiscible sulphide melt (one low in Rh and high in Cu, the other Rh-rich); both types of sulphide melt may have been present in the Tropoja deposit....

  2. Evaluation of hydrogen sulphide concentration and control in a sewer system.

    Science.gov (United States)

    Oviedo, Eugenio Recio; Johnson, Drew; Shipley, Heather

    2012-06-01

    This study focused on monitoring hydrogen sulphide (dissolved and atmospheric) generation and wastewater volumetric flow in a 21.4 km sewer line of the City of San Antonio, Texas. The results were used to evaluate daily and seasonal trends of atmospheric and dissolved sulphide, and to better apply sulphide control using ferrous sulphate to prevent odour and sewer pipe deterioration. As part of this study, the evaluation of a cost-effective dosing strategy with ferrous sulphate was performed to better control the sulphide contents in wastewater. Dosing studies were performed in the laboratory to find the required ratio of ferrous sulphate for acceptable sulphide removal. The results indicate a 1.25 mole ratio requirement, to reduce sulphide by 93%. Over a typical daily diurnal cycle, necessary dosing rates to maintain sulphide concentrations below 2mg varied between 0 and 36,777 mold(-1) with a daily average rate of 14,438 mol d(-1). If, instead of dosing at the maximum required rate, dosing was matched over the diurnal cycle, chemical savings would amount to 22,339 mold(-1) while achieving sulphide control. The approximate cost of the ferrous sulphate solution dosed is $0.14 per mol and this amount of chemical savings translates into roughly $2923 per day. Actual dosing cost for the hypothetical average day will be $1889 per day. These cost savings can easily recoup the required instrumentation costs to achieve this diurnal dose matching. PMID:22856291

  3. Allyl sulphides in olefin metathesis: catalyst considerations and traceless promotion of ring-closing metathesis.

    Science.gov (United States)

    Edwards, Grant A; Culp, Phillip A; Chalker, Justin M

    2015-01-11

    Allyl sulphides are reactive substrates in ruthenium-catalysed olefin metathesis reactions, provided each substrate is matched with a suitable catalyst. A profile of catalyst activity is described, along with the first demonstration of allyl sulphides as traceless promoters in relayed ring-closing metathesis reactions. PMID:25410944

  4. Investigation of the explosion hazards of hydrogen sulphide. (Phase II)

    International Nuclear Information System (INIS)

    The results of Phase II of an investigation directed towards quantifying the explosive hazards of hydrogen sulphide in air are described. This second and final phase is focussed on flame acceleration until detonation in obstacle environments simulating a heavy water plant. The results of previous experimental tests, both small and large scale, are compiled and summarized and the results of a series of flame acceleration tests are reported. These tests were performed in order to assess the potential for damaging explosions in simulated industrial environments with repeated obstacles. The experimented apparatus consisted of a channel 1.8 m x 1.8 m in cross-section and 15.5 m long. Two obstacle configurations were tested, corresponding to 500 mm or 220 mm diameter tubes mounted across the channel at regular intervals. Tests were performed with acetylene, propane and hydrogen sulphide fuels. The results of numerical simulation are also reported and compared with the observed results. Scaling predictions are also made. The key results are summarized in the main text, and detailed reports covering the various aspects are included in three annexes

  5. Arsenic removal from water by iron-sulphide minerals

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In bench-scaled experiments, iron-sulphide minerals, pyrite and pyrrhotite are used as adsorbents for arsenic removal from As-spiked water of As5+ and As3+ species. The adsorption rate, efficiency, As-adsorption stability and the associated pH conditions have been examined. Observations indicate that these iron-sulphide minerals are very efficient to adsorb arsenic from water for both As5+ and As3+ species. Similar to other studies, As3+-adsorption shows a slower rate than As3+. The stability of the adsorbed arsenic seems closely related to the pH values of the solution. A lower pH level commonly less than 4.0 is required to protect the adsorbed arsenic from serious oxidation and backward release. Fining of the mineral powders and shaking of the solution during adsorption enhance the adsorption efficiency and adsorption rate. For practical use of the method presented in this study, the waste produced should be managed with great care to keep it from redistribution over water system. A further study of the protection for the waste from oxidation on real water systems will greatly enhance the application of the strong ability of arsenic adsorption by these minerals, which is observed from this study.

  6. Evolution of Acid Mine Drainage Formation in Sulphidic Mine Tailings

    Directory of Open Access Journals (Sweden)

    Bernhard Dold

    2014-07-01

    Full Text Available Sulphidic mine tailings are among the largest mining wastes on Earth and are prone to produce acid mine drainage (AMD. The formation of AMD is a sequence of complex biogeochemical and mineral dissolution processes. It can be classified in three main steps occurring from the operational phase of a tailings impoundment until the final appearance of AMD after operations ceased: (1 During the operational phase of a tailings impoundment the pH-Eh regime is normally alkaline to neutral and reducing (water-saturated. Associated environmental problems include the presence of high sulphate concentrations due to dissolution of gypsum-anhydrite, and/or effluents enriched in elements such as Mo and As, which desorbed from primary ferric hydroxides during the alkaline flotation process. (2 Once mining-related operations of the tailings impoundment has ceased, sulphide oxidation starts, resulting in the formation of an acidic oxidation zone and a ferrous iron-rich plume below the oxidation front, that re-oxidises once it surfaces, producing the first visible sign of AMD, i.e., the precipitation of ferrihydrite and concomitant acidification. (3 Consumption of the (reactive neutralization potential of the gangue minerals and subsequent outflow of acidic, heavy metal-rich leachates from the tailings is the final step in the evolution of an AMD system. The formation of multi-colour efflorescent salts can be a visible sign of this stage.

  7. 2D X-ray and FTIR micro-analysis of the degradation of cadmium yellow pigment in paintings of Henri Matisse

    Science.gov (United States)

    Pouyet, E.; Cotte, M.; Fayard, B.; Salomé, M.; Meirer, F.; Mehta, A.; Uffelman, E. S.; Hull, A.; Vanmeert, F.; Kieffer, J.; Burghammer, M.; Janssens, K.; Sette, F.; Mass, J.

    2015-11-01

    The chemical and physical alterations of cadmium yellow (CdS) paints in Henri Matisse's The Joy of Life (1905-1906, The Barnes Foundation) have been recognized since 2006, when a survey by portable X-ray fluorescence identified this pigment in all altered regions of the monumental painting. This alteration is visible as fading, discoloration, chalking, flaking, and spalling of several regions of light to medium yellow paint. Since that time, synchrotron radiation-based techniques including elemental and spectroscopic imaging, as well as X-ray scattering have been employed to locate and identify the alteration products observed in this and related works by Henri Matisse. This information is necessary to formulate one or multiple mechanisms for degradation of Matisse's paints from this period, and thus ensure proper environmental conditions for the storage and the display of his works. This paper focuses on 2D full-field X-ray Near Edge Structure imaging, 2D micro-X-ray Diffraction, X-ray Fluorescence, and Fourier Transform Infra-red imaging of the altered paint layers to address one of the long-standing questions about cadmium yellow alteration—the roles of cadmium carbonates and cadmium sulphates found in the altered paint layers. These compounds have often been assumed to be photo-oxidation products, but could also be residual starting reagents from an indirect wet process synthesis of CdS. The data presented here allow identifying and mapping the location of cadmium carbonates, cadmium chlorides, cadmium oxalates, cadmium sulphates, and cadmium sulphides in thin sections of altered cadmium yellow paints from The Joy of Life and Matisse's Flower Piece (1906, The Barnes Foundation). Distribution of various cadmium compounds confirms that cadmium carbonates and sulphates are photo-degradation products in The Joy of Life, whereas in Flower Piece, cadmium carbonates appear to have been a [(partially) unreacted] starting reagent for the yellow paint, a role

  8. Global warming enhances sulphide stress in a key seagrass species (NW Mediterranean).

    Science.gov (United States)

    García, Rosa; Holmer, Marianne; Duarte, Carlos M; Marbà, Núria

    2013-12-01

    The build-up of sulphide concentrations in sediments, resulting from high inputs of organic matter and the mineralization through sulphate reduction, can be lethal to the benthos. Sulphate reduction is temperature dependent, thus global warming may contribute to even higher sulphide concentrations and benthos mortality. The seagrass Posidonia oceanica is very sensitive to sulphide stress. Hence, if concentrations build up with global warming, this key Mediterranean species could be seriously endangered. An 8-year monitoring of daily seawater temperature, the sulphur isotopic signatures of water (δ(34)S(water)), sediment (δ(34)SCRS ) and P. oceanica leaf tissue (δ(34)S(leaves)), along with total sulphur in leaves (TS(leaves)) and annual net population growth along the coast of the Balearic archipelago (Western Mediterranean) allowed us to determine if warming triggers P. oceanica sulphide stress and constrains seagrass survival. From the isotopic S signatures, we estimated sulphide intrusion into the leaves (F(sulphide)) and sulphur incorporation into the leaves from sedimentary sulphides (SS(leaves)). We observed lower δ(34)S(leaves), higher F(sulphide) and SS(leaves) coinciding with a 6-year period when two heat waves were recorded. Warming triggered sulphide stress as evidenced by the negative temperature dependence of δ(34)S(leaves) and the positive one of F(sulphide), TS(leaves) and SS(leaves). Lower P. oceanica net population growth rates were directly related to higher contents of TS(leaves). At equivalent annual maximum sea surface water temperature (SST(max)), deep meadows were less affected by sulphide intrusion than shallow ones. Thus, water depth acts as a protecting mechanism against sulphide intrusion. However, water depth would be insufficient to buffer seagrass sulphide stress triggered by Mediterranean seawater summer temperatures projected for the end of the 21st century even under scenarios of moderate greenhouse gas emissions, A1B

  9. Chalcophile element partitioning into magmatic sulphides: the effect of silicate melt composition

    Science.gov (United States)

    Kiseeva, Kate; Wood, Bernard

    2016-04-01

    Partitioning of many elements between sulphide and silicate melts is a function of the FeO content of the silicate liquid (Kiseeva and Wood, 2013). The theoretical relationship is a linear one between LogDM (DM=[M]sulph/[M]sil) and -log[FeO] with a slope of n/2, where n is the valency of trace element M. In practice we find that the slope deviates from the theoretical one because of the presence of oxygen in the sulphide. In our recent study we investigated the effects of sulphide composition and temperature on chalcophile element partitioning between sulphide and silicate liquids (Kiseeva and Wood, 2015). We have concluded that partitioning of most chalcophile elements is a strong function of the oxygen (or FeO) content of the sulphide. As expected, lithophile elements partition more strongly into sulphide as its oxygen content increases, while chalcophile elements enter sulphide less readily with increasing oxygen. The effect of Ni and Cu content of sulphide is significantly smaller than the effect of oxygen, while the effects of temperature are large only for a number of elements (such as Ni, Cu, Ag). In this study we show that in addition to the effect of sulphide composition, for certain elements the effect of silicate melt composition on sulphide/silicate partitioning can be quite large. For instance, within the range of NBO/T between 0.5 and 2 the DTlsulph/sil changes in order of magnitude. For the elements, like Pb, partition coefficient does not seem to change much with the silicate melt composition, while for Sb the effect of the silicate melt composition on D is a factor of 3. Partitioning of chalcophile elements into more evolved, alkali-rich and felsic magmas is estimated to be very different from the partitioning into basaltic melts, mainly due to the strong effects of temperature and alkali components. Although it is highly likely that sulphide is in solid form at liquidus temperatures for dacite and rhyolite and thus the partitioning of chalcophile

  10. Dry sliding friction and wear characteristics of Fe-C-Cu alloy containing molybdenum di sulphide

    Energy Technology Data Exchange (ETDEWEB)

    Dhanasekaran, S. [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Gnanamoorthy, R. [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India)]. E-mail: gmoorthy@iitm.ac.in

    2007-07-01

    Sintered steels find increasing application as bearings and gears due to economical and technical reasons. Materials used for making these machine elements need to have high strength, good wear resistance and low coefficient of friction. An attempt is made to develop molybdenum di sulphide added iron-copper-carbon sintered steels using simple single stage compaction and sintering elemental powders. Friction and wear characteristics of the developed materials were evaluated using cylindrical specimens in a pin-on-disc sliding apparatus. Addition of molybdenum di sulphide increases the compressibility and increases the part density. Strength and hardness of the molybdenum di sulphide added compositions are better than the base composition. Addition of the 3% molybdenum di sulphide is found to be beneficial in improving friction and wear characteristics. Higher amount of brittle phases in the 5% molybdenum di sulphide added sample contributes to the reduction in the wear resistance.

  11. Sulphide melt evolution in upper mantle to upper crust magmas, Tongling, China

    Institute of Scientific and Technical Information of China (English)

    Yilun Du; Xinlong Qin; Calvin G. Barnes; Yi Cao; Qian Dong; Yangsong Du

    2014-01-01

    Sulphide inclusions, which represent melts trapped in the minerals of magmatic rocks and xenoliths, provide important clues to the behaviour of immiscible sulphide liquids during the evolution of magmas and the formation of NieCueFe deposits. We describe sulphide inclusions from unique ultramafic clots within mafic xenoliths, from the mafic xenoliths themselves, and from the three silica-rich host plutons in Tongling, China. For the first time, we are able to propose a general framework model for the evolution of sulphide melts during the evolution of mafic to felsic magmas from the upper mantle to the upper crust. The model improves our understanding of the sulphide melt evolution in upper mantle to upper crust magmas, and provides insight into the formation of stratabound skarn-type FeeCu polymetallic deposits associated with felsic magmatism, thus promising to play an important role during prospecting for such deposits.

  12. Zinc and cadmium monosalicylates

    Energy Technology Data Exchange (ETDEWEB)

    Kharitonov, Yu.Ya.; Tujebakhova, Z.K. (Moskovskij Khimiko-Tekhnologicheskij Inst. (USSR))

    1984-06-01

    Zinc and cadmium monosalicylates of the composition MSal, where M-Zn or Cd, Sal - twice deprotonated residue of salicylic acid O-HOC/sub 6/H/sub 4/COOH (H/sub 2/Sal), are singled out and characterized. When studying thermograms, thermogravigrams, IR absorption spectra, roentgenograms of cadmium salicylate compounds (Cd(OC/sub 6/H/sub 4/COO) and products of their thermal transformations, the processes of thermal decomposition of the compounds have been characterized. The process of cadmium monosalicylate decomposition takes place in one stage. Complete loss of salicylate acido group occurs in the range of 320-460 deg. At this decomposition stage cadmium oxide is formed. A supposition is made that cadmium complex has tetrahedral configuration, at that, each salicylate group plays the role of tetradentate-bridge ligand. The compound evidently has a polymer structure.

  13. Microwave-assisted synthesis of BSA-modified silver nanoparticles as a selective fluorescent probe for detection and cellular imaging of cadmium(II)

    International Nuclear Information System (INIS)

    We have developed a microwave-assisted method for the synthesis of silver nanoparticles (AgNPs) whose surface is modified with bovine serum albumin (BSA). The reaction involves reduction of the BSA-Ag(I) complex by tyrosine in strongly alkaline solution to form BSA-AgNPs. The reaction takes a few minutes only owing to rapid and uniform microwave heating. The modified AgNPs were characterized by UV–vis and fluorescence spectroscopy, transmission electron microscopy and X- ray photoelectron spectroscopy. The BSA-AgNPs are yellow and display luminescence with a maximum at 521 nm if excited at 465 nm. They have a hydrodynamic diameter of 3–5 nm and possess good colloidal stability in the pH 4.6 to 12.0 range. The fluorescence of the BSA-AgNPs is enhanced by Cd(II) ion due to the formation of a stable hybrid conjugate referred to as Cd-BSA-AgNPs. The effect was exploited to quantify Cd(II) in spiked real water samples with a 4.7 nM detection limit, and also to fluorescently image Cd(II) in Hepatoma cells. (author)

  14. Genomic and chromosomal damage in the marine mussel Mytilus galloprovincialis: Effects of the combined exposure to titanium dioxide nanoparticles and cadmium chloride.

    Science.gov (United States)

    Rocco, L; Santonastaso, M; Nigro, M; Mottola, F; Costagliola, D; Bernardeschi, M; Guidi, P; Lucchesi, P; Scarcelli, V; Corsi, I; Stingo, V; Frenzilli, G

    2015-10-01

    Titanium dioxide nanoparticles (TiO2-NPs) continuously released into waters, may cause harmful effects to marine organisms and their potential interaction with conventional toxic contaminants represents a growing concern for biota. We investigated the genotoxic potential of nanosized titanium dioxide (n-TiO2) (100 μg L(-1)) alone and in combination with CdCl2 (100 μg L(-1)) in Mytilus galloprovincialis after 4 days of in vivo exposure. RAPD-PCR technique and Micronucleus test were used to study genotoxicity. The results showed genome template stability (GTS) being markedly reduced after single exposure to n-TiO2 and CdCl2. Otherwise, co-exposure resulted in a milder reduction of GTS. Exposure to n-TiO2 was responsible for a significant increase of micronucleated cell frequency in gill tissue, while no chromosomal damage was observed after CdCl2 exposure as well as after combined exposure to both substances.

  15. Who farted? Hydrogen sulphide transport from Bardarbunga to Scandinavia

    CERN Document Server

    Grahn, Håkan; Brännström, Niklas

    2015-01-01

    On September 9 2014 several incidences of foul smell (rotten eggs) were reported on the coast of Norway (in particular in the vicinity of Molde) and then on September 10 in the interior parts of county V\\"asterbotten, Sweden. One of the theories that were put forward was that the foul smell was due to degassing of the Bardarbunga volcano on Iceland. Using satellite images (GOME-1,-2) of the sulphur dioxide, SO_2, contents in the atmosphere surrounding Iceland to estimate flux of SO_2 from the volcano and an atmospheric transport model, PELLO, we vindicate this theory: we argue that the cause for the foul smell was hydrogen sulphide originating from Bardarbunga. The model concentrations are also compared to SO_2 concentration measurements from Muonio, Finland.

  16. Bioleaching of pollymetallic sulphide concentrate using thermophilic bacteria

    Directory of Open Access Journals (Sweden)

    Vuković Milovan

    2014-01-01

    Full Text Available An extreme thermophilic, iron-sulphur oxidising bacterial culture was isolated and adapted to tolerate high metal and solids concentrations at 70°C. Following isolation and adaptation, the culture was used in a batch bioleach test employing a 5-l glass standard magnetic agitated and aerated reactor, for the bioleaching of a copper-lead-zinc collective concentrate. The culture exhibited stable leach performance over the period of leach operation and overall copper and zinc extractions higher than 97%. Lead sulphide is transformed into lead sulphate remaining in the bioleach residue due to the low solubility in sulphate media. Brine leaching of bioleach residue yields 95% lead extraction. [Projekat Ministarstva nauke Republike Srbije, br. 34023

  17. Failure rate of piping in hydrogen sulphide systems

    International Nuclear Information System (INIS)

    The objective of this study is to provide information about piping failures in hydrogen sulphide service that could be used to establish failures rates for piping in 'sour service'. Information obtained from the open literature, various petrochemical industries and the Bruce Heavy Water Plant (BHWP) was used to quantify the failure analysis data. On the basis of this background information, conclusions from the study and recommendations for measures that could reduce the frequency of failures for piping systems at heavy water plants are presented. In general, BHWP staff should continue carrying out their present integrity and leak detection programmes. The failure rate used in the safety studies for the BHWP appears to be based on the rupture statistics for pipelines carrying sweet natural gas. The failure rate should be based on the rupture rate for sour gas lines, adjusted for the unique conditions at Bruce

  18. Field emission from crystalline copper sulphide nanowire arrays

    Science.gov (United States)

    Chen, Jun; Deng, S. Z.; Xu, N. S.; Wang, Suhua; Wen, Xiaogang; Yang, Shihe; Yang, Chunlei; Wang, Jiannong; Ge, Weikun

    2002-05-01

    Straight crystalline copper sulphide (Cu2S) nanowire arrays have been grown by using a simple gas-solid reaction at room temperature. These were demonstrated to exhibit semiconductor properties. Field emission was observed at a field of ˜6 MV/m, and its current-field characteristics deviate from Fowler-Nordheim theory, i.e., showing a nonlinear Fowler-Nordheim plot. The uniform emission from the whole arrays was observed using transparent anode technique, and their variation with applied field was recorded. The emission from individual nanowires was also studied using a field emission microscope, and was found to consist of a number of spatially resolved diffuse spots. Finally, stable emission current at different levels and over time was recorded. These findings indicate that semiconductor nanowires as cold cathode have a potential future, worthy of further comprehensive investigation. The technical importance of using semiconductor nanowires as cold cathode emitter is given.

  19. What's that smell? Hydrogen sulphide transport from Bardarbunga to Scandinavia

    Science.gov (United States)

    Grahn, Håkan; von Schoenberg, Pontus; Brännström, Niklas

    2015-09-01

    On Sep 9 2014 several incidences of foul smell (rotten eggs) were reported on the coast of Norway (in particular in the vicinity of Molde) and then on Sep 10 in the interior parts of county Västerbotten, Sweden. One of the theories that were put forward was that the foul smell was due to degassing of the Bardarbunga volcano on Iceland. Using satellite images (GOME-1,-2) of the sulphur dioxide, SO2, contents in the atmosphere surrounding Iceland to estimate flux of SO2 from the volcano and an atmospheric transport model, PELLO, we vindicate this theory: we argue that the cause for the foul smell was hydrogen sulphide originating from Bardarbunga. The model concentrations are also compared to SO2 concentration measurements from Muonio, Finland.

  20. Extremophiles in Mineral Sulphide Heaps: Some Bacterial Responses to Variable Temperature, Acidity and Solution Composition

    Directory of Open Access Journals (Sweden)

    Helen R. Watling

    2015-07-01

    Full Text Available In heap bioleaching, acidophilic extremophiles contribute to enhanced metal extraction from mineral sulphides through the oxidation of Fe(II and/or reduced inorganic sulphur compounds (RISC, such as elemental sulphur or mineral sulphides, or the degradation of organic compounds derived from the ore, biota or reagents used during mineral processing. The impacts of variable solution acidity and composition, as well as temperature on the three microbiological functions have been examined for up to four bacterial species found in mineral sulphide heaps. The results indicate that bacteria adapt to sufficiently high metal concentrations (Cu, Ni, Co, Zn, As to allow them to function in mineral sulphide heaps and, by engaging alternative metabolic pathways, to extend the solution pH range over which growth is sustained. Fluctuating temperatures during start up in sulphide heaps pose the greatest threat to efficient bacterial colonisation. The large masses of ores in bioleaching heaps mean that high temperatures arising from sulphide oxidation are hard to control initially, when the sulphide content of the ore is greatest. During that period, mesophilic and moderately thermophilic bacteria are markedly reduced in both numbers and activity.

  1. Surface Phenomena at Silver Nanoparticles in the Context of Toxicology

    DEFF Research Database (Denmark)

    Miclaus, Teodora

    2015-01-01

    sulphide particles in close proximity to the silver nanoparticle surface, as shown in the second study. The identification of spontaneous sulfidation under in vitro settings is a novel finding with important implications for toxicity, as Ag2S traps toxic silver ions into an insoluble compound. Increased...

  2. Chemical extraction of copper from copper sulphide ores of Pakistan by roast leach method

    International Nuclear Information System (INIS)

    Copper ores, containing both complex sulphide minerals and those containing chalcopyrite mineral, were studied for the extraction of copper by leaching after roasting. Roasting at 650 deg. C for 30 min rendered the ore leachable in dilute sulphuric acid of 2.5% concentration. The process of metal extraction would be of hydro metallurgical importance for low to high grade sulphide and polymetallic complex sulphide ores occurring in Pakistan. The kinetic models of roasting reaction fit phase boundary as well as diffusion reaction mechanism. (author)

  3. Cadmium status in Egypt

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    It is inferred from these studies that releases of Cd are still increasing and it is recommended that measures must be taken to reduce emissions of cadmium. Any cadmium discharged into the Egyptian environment may move from one compartment to another at varying rates,resulting in an accumulation in compartments such as soils and biota. Such accumulation can be expected to increase with continued emissions,and attention should be given to all sources of cadmium, natural as well as anthropogenic especially in the industrial cities in Egypt. Cadmium present in sewage, as well as industrial effluent (also, other liquid and solid wastes) and sewage sludge will increase levels in soils and is xpected to contribute to dietary levels and body burdens. The current information indicates that such effects may have to be evaluated over long periods of time, possibly as long as 50 - 100 years.

  4. The Ioko-Dovyren layered massif (Southern Siberia, Russia): 2. Melt vs sulphide percolation process and modeling sulphide saturation in the parental magmas and original cumulates

    Science.gov (United States)

    Ariskin, Alexey; Danyushevsky, Leonid

    2013-04-01

    An important feature of the Dovyren intrusive complex [1] is its fertility due to the presence of massive sulphide ores near the bottom of the Ioko-Dovyren massif (YDM, SW and NE margins), as well as PGE-reefs in anorthosites from the Ol-gabbronorite zone in the centre [2]. These observations argue for the importance of downward percolation of sulphides through the porous space of cumulates and probable link of this process with upward migration of intercumulus melts at a post-cumulus stage. Indirectly, this is supported by the basic conclusion on the open-system behavior of the magma chamber [1]. A key aspect of these speculations is the onset of sulphide immiscibility in YDM parental magmas and the original cumulates. To reconstruct the sulphide saturation history, we applied a newly developed sulphide version of COMAGMAT (ver. 5.2 [3]) to the rocks from the chilled zone of YDM and underlying ultramafic sills, by simulating the course of their crystallization coupled with the SCSS calculations. Modeled crystallization trajectories evidence for under-saturated nature of the most primitive parental magmas (1310oC, Fo88) from which the chilled rocks were crystallized, whereas more evolved rocks from the sills demonstrate sulphide saturation starting from their initial temperature (1190oC, Fo85), see [1]. This correlates with the absence of sulphide ores in the central parts of the pluton and their occurrence in underlying ultramafics and YDM border series containing olivine Fo~85. Another set of calculations was carried out to demonstrate the effect of bulk Ni contents in Ol cumulate piles on the evolution of SCSS during their post-cumulus crystallization [3]. To achieve the goal, two calculations by the COMAGMAT-5.2 model were carried out. The first one involved modelling equilibrium crystallization for an initial mixture of Ol (Fo88) and intercumulus melt (~1320oC), with the starting composition corresponding to that of a bottom Pl-dunite (2315 ppm NiO, 0.030 wt

  5. A spectrophotometric method for the determination of Hydrogen Sulphide sugar cane juice and water

    International Nuclear Information System (INIS)

    A sensitive spectrophotometric is developed for the determination of hydrogen sulphide in water and sugarcane juice. The method is based on the reaction of hydrogen sulphide with phospomolybdate (ammonium molybdate and phosphate) in sulphuric acid medium. The system obeys Lambert-Beer's law at 715 nm in the concentration range of 0.284-5.68 ug ml. Molar absorptivity, correlation coefficient and Sandell sensitivity values were found to be 5x10 l mol cm, 0.9995 and 0.0494 ug cm respectively. The method was employed for the determination of hydrogen sulphide in sugar cane juice and in water samples. The results obtained were reproducible with acceptable standard deviation 0.1140-0.1337 and relative standard deviation varies from 0.0797-0.6038%. For comparison, hydrogen sulphide present in sugarcane juice and water samples were also determined separately following the methylene blue official method. The results of the proposed method compare well with the official method. (author)

  6. Anaerobic expanded granular sludge bed (EGSB reactor for the removal of sulphide by autotrophic denitrification

    Directory of Open Access Journals (Sweden)

    Carlos Dinamarca

    2014-01-01

    Full Text Available The Removal efficiency, load and N/S molar ratio, of an EGSB reactor for autotrophic sulphide denitrification operated for 96 days, were studied. The reactor was operated at high inlet sulphide concentrations between 0.25 to 3.00 g HS--S/L equivalents to loads between 5 to 250 g HS--S/m3∙h. Sulphide removals higher than 99 % were achieved. At a N/S molar ratio of 0.3 and 12 hours HRT the process was stable even during transition periods of influent sulphide concentration and pH (9.0-12.1. At N/S molar ratio of 1.3, granules lost some of their sedimentation properties and appeared to disintegrate. On average 94 +- 4 % of the equivalent inlet sulphur ended as elemental sulphur.

  7. Sulphide Resistance in the Cyanobacterium Microcystis aeruginosa: a Comparative Study of Morphology and Photosynthetic Performance Between the Sulphide-Resistant Mutant and the Wild-Type Strain.

    Science.gov (United States)

    Bañares-España, Elena; Del Mar Fernández-Arjona, María; García-Sánchez, María Jesús; Hernández-López, Miguel; Reul, Andreas; Mariné, Mariona Hernández; Flores-Moya, Antonio

    2016-05-01

    The cyanobacterium Microcystis aeruginosa is a mesophilic freshwater organism, which cannot tolerate sulphide. However, it was possible to isolate a sulphide-resistant (S (r) ) mutant strain that was able to survive in a normally lethal medium sulphide. In order to evaluate the cost of the mutation conferring sulphide resistance in the S (r) strain of M. aeruginosa, the morphology and the photosynthetic performance were compared to that found in the wild-type, sulphide-sensitive (S (s) ) strain. An increase in size and a disrupted morphology was observed in S (r) cells in comparison to the S (s) counterpart. Phycoerythrin and phycocyanin levels were higher in the S (r) than in the S (s) cells, whereas a higher carotenoid content, per unit volume, was found in the S (s) strain. The irradiance-saturated photosynthetic oxygen-production rate (GPR max) and the photosynthetic efficiency (measured both by oxygen production and fluorescence, α (GPR) and α (ETR)) were lower in the S (r) strain than in the wild-type. These results appear to be the result of package effect. On the other hand, the S (r) strain showed higher quantum yield of non-photochemical quenching, especially those regulated mechanisms (estimated throughout q N and Y(NPQ)) and a significantly lower slope in the maximum quantum yield of light-adapted samples (F v '/F m ') compared to the S (s) strain. These findings point to a change in the regulation of the quenching of the transition states (q T ) in the S (r) strain which may be generated by a change in the distribution of thylakoidal membranes, which somehow could protect metalloenzymes of the electron transport chain from the lethal effect of sulphide. PMID:26677166

  8. Application of the sulphide capacity theory on refining slags during LF treatment

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Sulphur has been reduced from 0.02wt% to 0.002wt% in 38 min average during 200 t ladle treatment in 2# steel plant of Capital Steel.The sulphide capacity and equilibrium sulphur distribution of slags are calculated and compared with the measured values.The results show that the KTH model is a useful tool for the prediction of sulphide capacity and sulphur distribution during ladle treatment; the desulphurization reactions are completed nearly in thermo-equilibrium.

  9. Dissolution of titanomagnetite and sulphidization in sediments from Lake Kinneret, Israel

    OpenAIRE

    Norbert Nowaczyk

    2011-01-01

    Magnetic extracts obtained from sediment cores recovered from Lake Kinneret, Israel, were subjected to comprehensive scanning electron microscope and in-line energy dispersive X-ray spectroscopy analyses. A variety of ferrimagnetic iron oxides and iron sulphide particles were identified, along with apparently non-magnetic iron sulphides. The majority of the iron oxides are titanomagnetites that have undergone pervasive dissolution, and in many cases were only preserved as skeletal, 3-D lattic...

  10. Surface-mediated structural transformation in CdTe nanoparticles dispersed in SiO2 thin films

    Science.gov (United States)

    Dayal, P. Babu; Mehta, B. R.; Aparna, Y.; Shivaprasad, S. M.

    2002-11-01

    Cadmium telluride nanoparticles dispersed in silicon dioxide thin films have been grown by magnetron sputtering technique followed by thermal annealing. The effect of thermal annealing conditions on the structure of the surface layer and the nanoparticle core has been studied. A structural transformation in the nanoparticle core mediated solely by surface effects has been observed for the first time in any nanoparticle system. The presence of a crystalline cadmium tellurium oxide layer modifies the crystal structure of the cadmium telluride nanoparticle core by introducing a large concentration of stacking faults.

  11. Plausible Mechanisms of Cadmium Carcinogenesis

    Science.gov (United States)

    Cadmium is a transition metal and an ubiquitous environmental and industrial pollutant. Laboratory animal studies and epidemiological studies have shown that exposure to cadmium is associated with various organ toxicities and carcinogenic effects. Several national and internation...

  12. Advances in research of sulphide ore textures and their implications for ore genesis

    Institute of Scientific and Technical Information of China (English)

    GU Lianxing; ZHENG Yuanchuan; TANG Xiaoqian; WU Changzhi; HU Wenxuan

    2006-01-01

    Important advances in research of sulphide ore textures in recent years have deepened our understanding of ore genesis of related mineral deposits. Pressure solution of sulphide minerals has been suggested as a mechanism for remobilization of ore materials,whereas pressure solution of the gangues is believed to raise the grade of the primary ores. We have known that precipitation of base metal sulphides from fluids prefers crystal and crack surfaces of pyrite to form overgrowth. Therefore, pyrite-bearing embryo beds in a sedimentary sequence can be acted as effective crystal seed beds and are favorable for fluid overprinting to form huge statabound deposits. Texture studies of various sulphides can be used to interpret the entire history of sedimentation, diagenesis, deformation and metamorphism of the ores. The study of chalcopyrite disease in sphalerite has brought about the idea of zone refining, and given a new explanation to metal zonation in massive sulphide deposits. Ductile shearing of sulphide ores may form ore mylonites, which will become oreshoots enriched in Cu, Au and Ag during late-stage fluid overprinting. Despite that various modern analytical techniques are being rapidly developed, ore microscopy remains to be an unreplaceable tool for ore geologists. Combined with these modern techniques, this tool will help accelerate the development of theories on ore genesis.

  13. Cadmium absorption inhibitors for soil

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, S.

    1974-05-25

    Cadmium absorption by soil is one cause of soil pollution. Cadmium adsorption inhibitors were prepared by mixing alginic acid which contained brown algae (Ascophyllum nodosum) and an inorganic material, shell fossils. This mixture was highly effective in preventing cadmium absorption by the soil.

  14. Biological removal of dimethyl sulphide from sea water

    Science.gov (United States)

    Kiene, Ronald P.; Bates, Timothy S.

    1990-06-01

    DIMETHYL sulphide (DMS) is an important sulphur-containing trace gas in the atmosphere. It is present in oceanic surface waters at concentrations sufficient to sustain a considerable net flux of DMS from the oceans to the atmosphere, estimated to comprise nearly half of the global biogenic input of sulphur to the atmosphere1. DMS emitted from the oceans may be a precursor of tropospheric aerosols and of cloud condensation nuclei in the remote marine atmosphere, thereby affecting the Earth's radiative balance and thus its climate2-4. Relatively little is known, however, about the biogeochemical and physical processes that control the concentration of DMS in sea water. Here we present data from incubation experiments, carried out at sea, which show that DMS is removed by microbial activity. In the eastern, tropical Pacific Ocean, DMS turnover is dominated by biological processes, with turnover times for biological DMS removal generally more than ten (3-430) times faster than turnover by ventilation to the atmosphere. Thus biological consumption of DMS seems to be a more important factor than atmospheric exchange in controlling DMS concentrations in the ocean, and hence its flux to the atmosphere. These results have significant implications for climate feedback models involving DMS emissions3, and highlight the importance of the microbial food web in oceanic DMS cycling.

  15. Sulphide mineralization and wall-rock alteration in ophiolites and modern oceanic spreading centres

    Science.gov (United States)

    Koski, R.A.

    1983-01-01

    Massive and stockwork Fe-Cu-Zn (Cyprus type) sulphide deposits in the upper parts of ophiolite complexes represent hydrothermal mineralization at ancient accretionary plate boundaries. These deposits are probable metallogenic analogues of the polymetallic sulphide deposits recently discovered along modern oceanic spreading centres. Genetic models for these deposits suggest that mineralization results from large-scale circulation of sea-water through basaltic basement along the tectonically active axis of spreading, a zone of high heat flow. The high geothermal gradient above 1 to 2 km deep magma chambers emplaced below the ridge axis drives the convective circulation cell. Cold oxidizing sea-water penetrating the crust on the ridge flanks becomes heated and evolves into a highly reduced somewhat acidic hydrothermal solvent during interaction with basaltic wall-rock. Depending on the temperature and water/rock ratio, this fluid is capable of leaching and transporting iron, manganese, and base metals; dissolved sea-water sulphate is reduced to sulphide. At the ridge axis, the buoyant hydrothermal fluid rises through permeable wall-rocks, and fluid flow may be focussed along deep-seated fractures related to extensional tectonic processes. Metal sulphides are precipitated along channelways as the ascending fluid undergoes adiabatic expansion and then further cooling during mixing with ambient sub-sea-floor water. Vigorous fluid flow results in venting of reduced fluid at the sea-floor/sea-water interface and deposition of massive sulphide. A comparison of sulphide mineralization and wall-rock alteration in ancient and modern spreading centre environments supports this genetic concept. Massive sulphide deposits in ophiolites generally occur in clusters of closely spaced (floor underlying numerous deposits in Guaymas Basin consists of diatomaceous ooze and terrigenous clastic sediment that is intruded by diabase sills. Mound-like massive sulphide deposits, as much as 30

  16. Optimization and photophysics of cadmium selenide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Badr, Y. [National Institute of Laser Enhanced Science, Cairo University, Cairo (Egypt); Mahmoud, M.A. [Chemistry Department, Faculty of Science, Zagazig University, Zagazig (Egypt)]. E-mail: mahmoudchem@yahoo.com

    2005-12-01

    CdSe nanocrystallites of different sizes were prepared in polyvinyl alcohol (PVA) photopolymer films. Particle sizes were optimized by variation in the Cd to Se ions ratio up to 16:1 as well as doping in PVA. X-ray diffraction shows that the degree of crystallinity of PVA was found to decrease due to doping with CdSe NPs and having a cubic unit cell. The UV-vis absorption spectra for the CdSe NPs in both solutions and PVA films showed blue shifts with increasing the ratio of Cd ion leading to the decrease of the particle size. The photoluminescence spectra resulting from 441.5 nm He-Cd excitation of CdSe NPs in PVA show the same behavior of absorption spectra. A blue shift in most of the FT-IR and FT-Raman bands of PVA was observed due to the interaction between PVA and CdSe NPs, which increase by decreasing the particle size. The conductivity of PVA was found to increase by decreasing the particle size of CdSe NPs.

  17. A Biphasic Ligand Exchange Reaction on Cdse Nanoparticles: Introducing Undergraduates to Functionalizing Nanoparticles for Solar Cells

    Science.gov (United States)

    Zemke, Jennifer M.; Franz, Justin

    2016-01-01

    Semiconductor nanoparticles, including cadmium selenide (CdSe) particles, are attractive as light harvesting materials for solar cells. In the undergraduate laboratory, the size-tunable optical and electronic properties can be easily investigated; however, these nanoparticles (NPs) offer another platform for application-based tunability--the NP…

  18. Magnetic iron-nickel sulphides in the Pliocene and Pleistocene marine marls from the Vrica section (Calabria, Italy)

    OpenAIRE

    A.J. Van Velzen; Dekkers, M.J.; Zijderveld, J.D.A.

    1993-01-01

    The rock magnetic properties of the late Pliocene and early Pleistocene open-marine marls from the Vrica section in Calabria (Italy) point to magnetic sulphide as the main magnetic mineral and remanence carrier. The maximum blocking temperatures, however, are between 340 and 360°C, which is too high for stoichiometric monoclinic pyrrhotite. Magnetic concentrates of the sediment are rich in iron sulphide grains and iron-nickel sulphide grains. Microprobe observations show that most of the grai...

  19. Role of sulphide species on the behaviour of carbon steel envisioned for high-level radioactive disposal: interaction between sulphide and corrosion products

    International Nuclear Information System (INIS)

    This PhD work deals with the nuclear waste disposal. In France, it is envisaged by Andra (French national radioactive waste management agency) that high-level radioactive wastes will be confined in a glass matrix, stored in a stainless steel canister, it self placed in a carbon steel overpack. The wastes will then be stored at a depth of ∼500 m in a deep geological repository, drilled in a very stiff (indurated) clay (argillite) formation. The kinetics of corrosion expected for the overpack in this disposal concept are low and will stay low if the somehow protective rust layer that will develop initially on the steel surface remains undamaged. Local changes of the physico-chemical conditions may however degrade this layer and induce accelerated kinetics of corrosion. In particular, the growth of sulphate reducing bacteria (SRB) close to the steel overpack cannot be excluded and the sulphide species these micro-organisms produce may modify the corrosion process. The aim of this work was then to achieve a better understanding of the corrosion system constituted with steel, its rust layer mainly made of siderite FeCO3, and a sulphide-containing electrolyte. First, it proved necessary to characterise the iron sulphides involved in the corrosion processes by Raman micro-spectroscopy so as to study their formation and transformation mechanisms in various conditions of Fe(II) and S(-II) concentration, pH, temperature and aeration. It could be demonstrated that the Raman spectrum of mackinawite FeS, the compound that precipitated in any case from dissolved Fe(II) and S(-II) species with the experimental conditions considered here, depended on the crystallinity and oxidation state. Moreover, the mechanisms of the oxidation of mackinawite into greigite Fe3S4 in acidic anoxic solutions at 80 C could be described. Finally, iron sulphides, often present on archaeological artefacts, could be identified using Raman micro-spectroscopy. The compounds present were mainly

  20. Synthesis of cadmium selenide colloidal quantum dots in aquatic medium

    International Nuclear Information System (INIS)

    Cadmium selenide nanocrystals were prepared in water phase through facile wet chemistry technique with thioglycolic acid (TGA) acting as capping agent. Structures were characterized using X-ray diffraction (XRD), UV-vis absorption and photoluminescence spectroscopies. Depending on synthesis conditions nanoparticles exhibit photoluminescence with maximum in the region of 580 – 680 nm. Influence of technological parameters and component concentrations on nanocrystals average size and properties was studied

  1. Altered response to hydrogen sulphide during experimental colitis in rats.

    Science.gov (United States)

    Steidle, J; Würner, L; Diener, M

    2012-09-10

    Hydrogen sulphide (H(2) S) is produced in the intestine by sulphate-reducing bacteria and during metabolism of L-cysteine within the mucosa. This gasotransmitter induces anion secretion by stimulating enteric neurons and by a direct effect on epithelial cells. As H(2) S is discussed to exert both pro- and anti-inflammatory actions, we aimed to investigate the role of H(2) S during experimental colitis by comparing the effects of blockade of H(2) S-forming endogenous enzymes with the effect of a S-reduced diet to diminish microbial production of H(2) S. Rectal application of trinitrobenzenesulfonic acid (TNBS) was used to induce chronic colitis. The level of inflammation was assessed macroscopically and histologically. In Ussing chamber experiments, colonic specimens from TNBS-treated animals exhibited a higher tissue conductance, that is, a higher epithelial permeability, and a slightly reduced basal short-circuit current (a measure of net ion transport) in relation to non-inflamed control tissue. Analgetic treatment with flupirtine, a central antinociceptive analgetic, did not interfere with the induction of the inflammatory response so that all animals were treated with flupirtine to reduce pain and distress during the development of colitis. The secretory response evoked by an exogenous H(2) S donor, NaHS, was significantly decreased after induction of colitis, whereas the response to Ca(2+) - or cAMP-dependent secretagogues was unaltered. This downregulation was not observed in the colitis group fed on a S-reduced diet. The decreased NaHS response indicates a desensitization of the tissue by inflammation, which might be explained by an upregulation of colonic H(2) S production as described in some models of inflammation. PMID:22963333

  2. Microemulsion Synthesis of Nanoparticles

    Directory of Open Access Journals (Sweden)

    Gotić, M.

    2013-11-01

    Full Text Available Nanoparticles and nanomaterials have wide applications in electronics, physics, material design, being also utilized as sensors, catalysts, and more and more in biomedicine. Microemulsions are an exceptionally suitable medium for the synthesis of nanoparticles due to their thermodynamical stability, great solubility of both polar and nonpolar components, as well as their ability to control the size, dispersity and shape of the particles. This review presents microemulsion techniques for the synthesis of inorganic nanoparticles. It takes place in water-in-oil microemulsions by mixing one microemulsion with a cationic precursor, and the other with a precipitating or reducing agent, or by direct addition of reducing agents or gas (O2, NH3 ili CO2 into microemul sion (Fig. 1. Metal nanoparticles are used as catalysts, sensors, ferrofluids etc. They are produced by reducing the metal cation with a suitable reducing agent. In a similar way, one can prepare nanoparticles of alloys from the metal salts, provided that the metals are mutually soluble. The microemulsion technique is also suitable for depositing nanoparticles onto various surfaces. Highly active catalysts made from nanoparticles of Pt, Pd, Rh and other noble metals may be obtained in this way. Metal oxides and hydroxides may be prepared by hydrolysis or precipitation in the water core of microemulsion. Precipitation can be initiated by adding the base or precipitating agent into the microemulsion with water solution of metal ions. Similarly, nanoparticles may be prepared of sulphides, halogenides, cyanides, carbonates, sulphates and other insoluble metal salts. To prevent oxidation of nanoparticles, especially Fe, the particles are coated with inert metals, oxides, various polymers etc. Coating may provide additional functionality; e.g. coating with gold allows subsequent functionalization with organic compounds containing sulphur, due to the strong Au–S bond. Polymer coatings decrease

  3. Characteristics of hydrogen sulphide released from coal and biomass blends during co-pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Shang Lin-lin; Cheng Shi-qing; Zhang Hai-qing; Yin Bing-yi [Shandong University, Jinan (China). College of Energy and Power Engineering

    2007-10-15

    Thermal gravimetric analysis, gas chromatography and mass spectroscopy were used to study the characteristics of hydrogen sulphide released from the co-pyrolysis of biomass and coal blends. The effects of biomass on the hydrogen sulphide gas released from coal pyrolysis were studied. Results show that when the coal is blended with biomass the quantity of hydrogen sulphide released is affected. During the process of coal pyrolysis hydrogen sulphide is released in the temperature range 100-490{sup o}C but in the process of co-pyrolysis of coal with biomass it is released earlier, during the temperature range 200-490{sup o}C. This is because biomass is pyrolyzed earlier than coal. Abundant active methyl radicals and hydrogen are released providing hydrogen to combine with sulphur. The quantity of hydrogen sulphide is decreased with small proportions of biomass and increased with larger proportions. This is due to the accelerated effect of hydrogenation and the desulphurization effect of alkali metals in biomass. 8 refs., 1 tab.

  4. Sulphidation behaviour of advanced materials for elevated kraft recovery boiler conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yli-Olli, S.; Pohjanne, P.; Heikinheimo, L.; Kinnunen, T.; Pankakoski, P.H. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2007-06-15

    The behaviour of new kraft recovery boiler materials in reducing conditions has been evaluated in this study. Sanicro 38, Sanicro 36Mo, Sanicro 65, 4C54 and HR11N were tested in gas mixtures containing hydrogen sulphide (H{sub 2}S) and carbon monoxide (CO) with and without water vapour. Steel 304L and a basic carbon steel were used as reference materials. A thin (max. 1 'm) oxide layer, probably a spinel (FeCr{sub 2}O{sub 4}), was observed on some of the exposed materials in the tests with 15% water vapour. This layer protected the materials from sulphidation. The protective effect of water vapour was not eliminated by the increase in temperature from 400 deg C to 440 deg C or in H{sub 2}S concentration from 500 to 5000 ppm. However, water vapour did not protect carbon steel. Without water vapour, sulphidation started at low levels of H{sub 2}S and was accelerated by increasing H{sub 2}S concentration. The reference material 304L and Sanicro 36 Mo showed the best sulphidation resistance. The formed layers of corrosion products were analysed with EDS and compared to thermodynamic modelling by FactSage. In most cases the thermodynamic predictions agreed very well with the EDS analyses. The results suggest that alloying with molybdenum will restrain sulphidation. (orig.)

  5. Comparative study of ketoconazole versus selenium sulphide shampoo in pityriasis versicolor

    Directory of Open Access Journals (Sweden)

    Aggarwal K

    2003-03-01

    Full Text Available Forty patients suffering from pityriasis versicolor were treated with either 2% ketoconazole shampoo (20 patients or 2.5% selenium sulphide shampoo (20 patients, once a week for three weeks. On global assessment after one month of start of therapy, 19 (95% out of 20 patients treated with ketoconazole shampoo were cured while one case had mild residual disease. In selenium sulphide shampoo group, 17 (85% out of 20 patients were cured, one had mild residual disease and two had considerable residual disease. No significant difference was observed in the response rates in the two groups. Relapse occurred in one patient of ketoconazole group and two patients of selenium sulphide group during the follow - up period of three months.

  6. Spray pyrolysis deposition of indium sulphide thin films

    International Nuclear Information System (INIS)

    In2S3 thin films were grown by the chemical spray pyrolysis (CSP) method using the pneumatic spray set-up and compressed air as a carrier gas. Aqueous solutions containing InCl3 and SC(NH2)2 at a molar ratio of In/S = 1/3 and 1/6 were deposited onto preheated glass sheets at substrate temperatures Ts = 205-410 oC. The obtained films were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM,) optical transmission spectra, X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS). According to XRD, thin films deposited at Ts = 205-365 oC were composed of the (0 0 12) orientated tetragonal β-In2S3 phase independent of the In/S ratio in the spray solution. Depositions performed at Ts = 410 oC led to the formation of the In2O3 phase, preferably when the 1/3 solution was sprayed. Post-deposition annealing in air indicated that oxidation of the sulphide phase has a minor role in the formation of In2O3 at temperatures up to 450 oC. In2S3 films grown at Ts below 365 oC exhibited transparency over 70% in the visible spectral region and Eg of 2.90-2.96 eV for direct and 2.15-2.30 eV for indirect transitions, respectively. Film thickness and chlorine content decreased with increasing deposition temperatures. The XPS study revealed that the In/S ratio in the spray solution had a significant influence on the content of oxygen (Me-O, BE = 530.0 eV) in the In2S3 films deposited in the temperature range of 205-365 oC. Both XPS and EDS studies confirmed that oxygen content in the films deposited using the solution with the In/S ratio of 1/6 was substantially lower than in the films deposited with the In/S ratio of 1/3.

  7. Diffusive Transport of Sulphide through an Engineering Barrier System in a Deep Geological Repository

    Science.gov (United States)

    Briggs, S. A.; Sleep, B. E.; McKelvie, J. R. M.; Krol, M.

    2015-12-01

    Bentonite is a naturally occurring clay-rich sediment containing montmorillonite, a smectitic clay mineral that has a high cation exchange capacity and swells upon contact with water. Owing to these characteristics, highly compacted bentonite (HCB) is an often included component of engineered barrier systems (EBS) designed to protect used fuel containers (UFCs) in deep geological repositories (DGR) for high-level nuclear waste. The low water activity and high swelling pressure of HCB suppresses microbial activity and the related production of sulphide that could cause microbiologically influenced corrosion (MIC) of UFCs The Canadian Nuclear Waste Management Organization (NWMO) has chosen a UFC that consists of an inner steel core and outer copper coating which is resistant to corrosion. However, under anaerobic conditions, MIC can still contribute to UFC corrosion if sulphides are present in the groundwater. Therefore the EBS consisting of bentonite blocks and pellets has been designed to impede the movement of sulphides to the UFC. In order to examine the effectiveness of the EBS, a 3D numerical model was developed capable of simulating the diffusive transport of sulphide within the NWMO EBS. The model was developed using COMSOL Multiphysics, a finite element software package and is parametric which allows the impact of different repository layouts to be assessed. The developed model was of the entire NWMO placement room, as well as, a stand-alone UFC and included conservative assumptions such as a fully saturated system and a constant concentration boundary condition. The results showed that the highest sulphide flux occurred at the semi-spherical end caps of the UFC. Further studies examined the effect of sulphide hotspots and fractures, representing possible EBS failure mechanisms. The model results highlight that even with conservative assumptions the chosen EBS will effectively protect the UFC from microbiologically influenced corrosion.

  8. Cadmium in Sweden - environmental risks

    Energy Technology Data Exchange (ETDEWEB)

    Parkman, H.; Iverfeldt, Aa. [Swedish Environmental Research Inst. (Sweden); Borg, H.; Lithner, G. [Stockholm Univ. (Sweden). Inst. for Applied Environmental Research

    1998-03-01

    This report aims at assessing possible effects of cadmium in the Swedish environment. Swedish soils and soft freshwater systems are, due to a generally poor buffering capacity, severely affected by acidification. In addition, the low salinity in the Baltic Sea imply a naturally poor organism structure, with some important organisms living close to their limit of physiological tolerance. Cadmium in soils is mobilized at low pH, and the availability and toxicity of cadmium in marine systems are enhanced at low salinity. The Swedish environment is therefore extra vulnerable to cadmium pollution. The average concentrations of cadmium in the forest mor layers, agricultural soils, and fresh-waters in Sweden are enhanced compared to `back-ground concentrations`, with a general increasing trend from the north to the south-west, indicating strong impact of atmospheric deposition of cadmium originating from the central parts of Europe. In Swedish sea water, total cadmium concentrations, and the fraction of bio-available `free` cadmium, generally increases with decreasing salinity. Decreased emissions of cadmium to the environment have led to decreasing atmospheric deposition during the last decade. The net accumulation of cadmium in the forest mor layer has stopped, and even started to decrease. In northern Sweden, this is due to the decreased deposition, but in southern Sweden the main reason is increased leakage of cadmium from the topsoil as a consequence of acidification. As a result, cadmium in the Swedish environments is undergoing an extended redistribution between different soil compartments, and from the soils to the aquatic systems. 90 refs, 23 figs, 2 tabs. With 3 page summary in Swedish

  9. Stabilization of plasmon resonance in Cu2-xS semiconductor nanoparticles.

    Science.gov (United States)

    Georgieva, Zheni N; Tomat, Marshall A; Kim, Christian; Plass, Katherine E

    2016-07-12

    Controllable copper vacancy concentrations in copper chalcogenides are essential to any application that requires constant NIR absorption behavior, including cancer phototherapy and photovoltaics. Doping levels, however, can change spontaneously and with oxygen exposure. Treatment of copper sulphide nanoparticles with tetrathiomolybdate is shown here to stabilize vacancy-induced plasmon bands.

  10. Ion Exchange Processed CdS Nanorods in Powder Form Using Cadmium Hydroxide Nanowires By Wet Chemical Route

    Directory of Open Access Journals (Sweden)

    Savita L. Patil

    2010-06-01

    Full Text Available Simple, inexpensive and soft chemical route (wet chemical method was employed for the synthesis of bulk forms of cadmium hydroxide [Cd(OH2] nanowires bundles and their conversion to cadmium sulphide [CdS] nanorods at room temperature by simple anion exchange route. Due to difference in solubility product and diffusion rates of the Cd(OH2 and CdS, the anion exchange reaction was taken place and CdS nanorods were formed. CdS nanorods were characterized by X-ray diffraction (XRD, and scanning electron microscopy (SEM, energy-dispersive X-ray (EDX analysis. Since CdS is semi-conducting material, it has variety of potential applications, this work demonstrates a cost effective method for the synthesis of CdS nanorods in bulk form like CNT.

  11. Significance of porous structure on degradatin of 2 2' dichloro diethyl sulphide and 2 chloroethyl ethyl sulphide on the surface of vanadium oxide nanostructure

    International Nuclear Information System (INIS)

    Degradation of the king of chemical warfare agent, 2 2' dichloro diethyl sulphide (HD), and its simulant 2 chloroethyl ethyl sulphide (CEES) were investigated on the surface of porous vanadium oxide nanotubes at room temperature (30 ± 2°C ). Reaction kinetics was monitored by GC-FID technique and the reaction products were characterized by GC-MS. Data indicates that HD degraded faster relative to CEES inside the solid decontaminant compared to the reported liquid phase degradation of CEES and HD. Data explores the role of hydrolysis, elimination and oxidation reactions in the detoxification of HD and CEES and the first order rate constant and t1/2 were calculated to be 0.026 h-1, 26.6 h for CEES and 0.052 h-1, 13.24 h for HD. In this report faster degradation of HD compared to CEES was explained on the basis of porous structure.

  12. CADMIUM – ENVIRONMENTAL HAZARD

    Directory of Open Access Journals (Sweden)

    Henryka Langauer-Lewowicka

    2010-06-01

    Full Text Available The paper presents some information about current status of cadmium as an environmental health problem. Agricultural uses of phosphate fertilizers, sewage sludge and industrial uses of Cd are the major source of widespread of this metal at trace levels into the general environment and human foodstuffs. It is well known that high cadmium (Cd exposure causes renal damage, anemia, enteropathy, osteoporosis, osteomalacia, whereas the dose-response relationship at low levels exposure is less established. During the last decade an increasing number of studies have found an adverse health effects due to low environmental exposure to Cd. Many authors try to determine the relationship between Cd intake and Cd toxicity indicators, especially dealing renal tubular damage. The level of b2-microglobulin in urine is regarded as the most sensitive biomarker of renal disfunction due to low environmental Cd concentrations.

  13. Cadmium sulfite hexahydrate revisited

    Directory of Open Access Journals (Sweden)

    Sergio Baggio

    2008-07-01

    Full Text Available The present structural revision of the title compound, tetracadmium tetrasulfite hexahydrate, [Cd4(SO34(H2O5]·H2O, is a low-temperature upgrade (T = 100 K and R = 0.017 of the original room-temperature structure reported by Kiers & Vos [Cryst. Struct. Commun. (1978. 7, 399–403; T = 293 K and R = 0.080. The compound is a three-dimensional polymer with four independent cadmium centres, four sulfite anions and six water molecules, five of them coordinated to two cadmium centres and the remaining one an unbound solvent molecule which completes the asymmetric unit. There are two types of cadmium environment: CdO8 (through four chelating sulfite ligands and CdO6 (by way of six monocoordinated ligands. The former groups form planar arrays [parallel to (001 and separated by half a unit cell translation along c], made up of chains running along [110] and [overline{1}10], respectively. These chains are, in turn, interconnected both in an intraplanar as well as in an interplanar fashion by the latter CdO6 polyhedra into a tight three-dimensional framework. There is, in addition, an extensive network of hydrogen bonds, in which all 12 water H atoms act as donors and eight O atoms from all four sulfite groups and two water molecules act as acceptors.

  14. Behaviour of Zinc Complexes and Zinc Sulphide Nanoparticles Revealed by Using Screen Printed Electrodes and Spectrometry

    Directory of Open Access Journals (Sweden)

    Lukas Nejdl

    2013-10-01

    Full Text Available In this study, we focused on microfluidic electrochemical analysis of zinc complexes (Zn(phen(hisCl2, Zn(hisCl2 and ZnS quantum dots (QDs using printed electrodes. This method was chosen due to the simple (easy to use instrumentation and variable setting of flows. Reduction signals of zinc under the strictly defined and controlled conditions (pH, temperature, flow rate, accumulation time and applied potential were studied. We showed that the increasing concentration of the complexes (Zn(phen(hisCl2, Zn(hisCl2 led to a decrease in the electrochemical signal and a significant shift of the potential to more positive values. The most likely explanation of this result is that zinc is strongly bound in the complex and its distribution on the electrode is very limited. Changing the pH from 3.5 to 5.5 resulted in a significant intensification of the Zn(II reduction signal. The complexes were also characterized by UV/VIS spectrophotometry, chromatography, and ESI-QTOF mass spectrometry.

  15. Organic Composition of Sulphide Ores in the Okinawa Trough and Its Implications

    Institute of Scientific and Technical Information of China (English)

    张绮玲; 侯增谦; 唐邵华

    2001-01-01

    A preliminary organic geochemical study shows that the sulphide ores from the hydrothermal deposit of the Okinawa Trough are generally low in the total organic carbon and extremely low in the soluble organic matter. In the aliphatic hydrocarbon fraction, the n-alkanes range from C15 to C35, with usual maxima in the middle n-C20 region and strong odd-carbon number predominance when n > C25 (CPI = 1.2). The dominant analog in the aromatic fraction is phenanthrene, a polynuclear aromatic hydrocarbon, which provides evidence for hydrothermal activity. The organic matter derived mainly from marine planktonic and terrigenous vascular plants is entrapped in a high-temperature regime such as an active chimney and cooled quickly in the sulphide ores on the seafloor. Organic matter and sulphides are definitely products of a high-temperature alteration. The biomarker compounds indicate that the ores are formed under low Eh and pH conditions梐 reducing to anoxic environment, which is favourable for sulphates to be reduced into sulphides by biogenic (bacterial) or abiogenic activity.

  16. Kinetics and mechanism of the oxidation of organic sulphides by 2,2'-bipyridinium chlorochromate

    Indian Academy of Sciences (India)

    Shashi Vyas; Pradeep K Sharma

    2002-04-01

    The oxidation of 34 organic sulphides by 2,2'-bipyridinium chlorochromate (BPCC) resulted in the formation of the corresponding sulphoxides. The reaction is first order with respect to both BPCC and the sulphide, and is catalysed by hydrogen ions. The hydrogen-ion dependence has the form: obs = a+b [H+]. The oxidation was studied in 19 different organic solvents. An analysis of the solvent effect by Swain’s equation showed that the both cation- and anion-solvating powers of the solvents play important roles. The rates of oxidation meta- and -substituted phenyl methyl sulphides were correlated with Charton’s LDR equation. The rates of the -compounds showed excellent correlation with the LDRS equation. Oxidation of the -compounds is more susceptible to the delocalization effect. Oxidation of the -compounds exhibited a greater dependence on the field effect. In the oxidation of the -compounds, the contribution of delocalized effect is slightly more than that of the field effect. The oxidation of alkyl phenyl sulphides is subject to both polar and steric effects of the alkyl groups. Polar reaction constants are negative, indicating an electron-deficient sulphur centre in the rate-determining step. A mechanism involving formation of a sulphurane intermediate in the slow step has been proposed.

  17. Biological sulphide removal from anaerobically treated domestic sewage: reactor performance and microbial community dynamics.

    Science.gov (United States)

    Garcia, Graziella Patrício Pereira; Diniz, Renata Côrtes Oliveira; Bicalho, Sarah Kinaip; Franco, Vitor Araujo de Souza; Gontijo, Eider Max de Oliveira; Toscano, Rodrigo Argolo; Canhestro, Kenia Oliveira; Santos, Merly Rita Dos; Carmo, Ana Luiza Rodrigues Dias; Lobato, Livia Cristina S; Brandt, Emanuel Manfred F; Chernicharo, Carlos A L; Calabria de Araujo, Juliana

    2015-01-01

    We developed a biological sulphide oxidation system and evaluated two reactors (shaped similar to the settler compartment of an up-flow anaerobic sludge blanket [UASB] reactor) with different support materials for biomass retention: polypropylene rings and polyurethane foam. The start-up reaction was achieved using microorganisms naturally occurring on the open surface of UASB reactors treating domestic wastewater. Sulphide removal efficiencies of 65% and 90% were achieved with hydraulic retention times (HRTs) of 24 and 12 h, respectively, in both reactors. However, a higher amount of elemental sulphur was formed and accumulated in the biomass from reactor 1 (20 mg S(0) g(-1) VTS) than in that from reactor 2 (2.9 mg S(0) g(-1) VTS) with an HRT of 24 h. Denaturing gradient gel electrophoresis (DGGE) results revealed that the the pink and green biomass that developed in both reactors comprised a diverse bacterial community and had sequences related to phototrophic green and purple-sulphur bacteria such as Chlorobium sp., Chloronema giganteum, and Chromatiaceae. DGGE band patterns also demonstrated that bacterial community was dynamic over time within the same reactor and that different support materials selected for distinct bacterial communities. Taken together, these results indicated that sulphide concentrations of 1-6 mg L(-1) could be efficiently removed from the effluent of a pilot-scale UASB reactor in two sulphide biological oxidation reactors at HRTs of 12 and 24 h, showing the potential for sulphur recovery from anaerobically treated domestic wastewater.

  18. Preservation of atmospheric dimethyl sulphide samples on Tenax in sea-to-air flux measurements

    NARCIS (Netherlands)

    Zemmelink, H.J.; Gieskes, W.W C; Holland, P.M.; Dacey, J.W

    2002-01-01

    The low concentration of dimethyl sulphide (DMS) in the atmosphere makes it necessary to concentrate the gas before gas-chromatographic analysis. One of the preferred methods has been to use a cold Tenax adsorbent in this concentration step. DMS concentration onto Tenax-TA traps is shown to be sensi

  19. Biogenic catalysis in sulphide minerals' weathering processes and acid mine drainage genesis.

    Science.gov (United States)

    Kušnierová, Mária; Praščáková, Mária; Nowak, Anna K; Gorazda, Katarzyna; Wzorek, Zbigniew

    2014-01-01

    Bioleaching and biogenesis are the main outputs from a large group of environmental processes participating in the natural material cycle, used in raw materials processing. Bio-oxidation reactions are the main basis for bioleaching procedures, often participating in parallel leaching processes. During the leaching processes of polycomponent sulphide substrates, the factor of process selection also plays an important role, being in direct relation to the electric properties and galvanic effect occurring between the individual components of the leaching substrate. This work gives a summary of the results of a research focused on the possibilities of using biotechnological procedures for treatment of Slovak sulphide ores. The object of the research is extraction of valuable metals, undesirable admixtures and degradation of crystal lattice of sulphides for subsequent chemical leaching processing of precious metals. The results of experiments on the existence of biogenic processes in situ on waste dumps from exploitation containing residual sulphides are also presented. The processes result in acid mine drainage water generation. These waters are strongly mineralised (over 48 g/L) and of low pH; that is why they are very caustic. The arsenic content (2.558 mg/L) in outflowing waters from old mines is high and over the limits set by the law. PMID:24445359

  20. Cadmium in blood and hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Eum, Ki-Do; Lee, Mi-Sun [Department of Environmental Health, Graduate School of Public Health and Institute of Health and Environment, Seoul National University, Seoul (Korea, Republic of); Paek, Domyung [Department of Environmental Health, Graduate School of Public Health and Institute of Health and Environment, Seoul National University, Seoul (Korea, Republic of)], E-mail: paekdm@snu.ac.kr

    2008-12-15

    Objectives:: This study is to examine the effect of cadmium exposure on blood pressure in Korean general population. Methods:: The study population consisted of 958 men and 944 women who participated in the 2005 Korean National Health and Nutrition Examination Survey (KNHANES), in which blood pressure and blood cadmium were measured from each participant. Results:: The mean blood cadmium level was 1.67 {mu}g/L (median level 1.55). The prevalence of hypertension was 26.2%. The blood cadmium level was significantly higher among those subjects with hypertension than those without (mean level 1.77 versus 1.64 {mu}g/dL). After adjusting for covariates, the odds ratio of hypertension comparing the highest to the lowest tertile of cadmium in blood was 1.51 (95% confidence interval 1.13 to 2.05), and a dose-response relationship was observed. Systolic, diastolic, and mean arterial blood pressure were all positively associated with blood cadmium level, and this effect of cadmium on blood pressure was markedly stronger when the kidney function was reduced. Conclusions:: Cadmium exposures at the current level may have increased the blood pressure of Korean general population.

  1. Projectbeschrijving Cadmium-informatiepunt (CIP)

    NARCIS (Netherlands)

    Meijer PJ

    1989-01-01

    To minimize the use of cadmium the Central Government has decided to perform the purchase of products and materials within the Central Government as much as possible within the Draft Cadmium Decree. The activities to achieve this are as far as could be seen at the start of the project in june 19

  2. Projectbeschrijving Cadmium-informatiepunt (CIP)

    OpenAIRE

    Meijer PJ

    1989-01-01

    To minimize the use of cadmium the Central Government has decided to perform the purchase of products and materials within the Central Government as much as possible within the Draft Cadmium Decree. The activities to achieve this are as far as could be seen at the start of the project in june 1989, mentioned in this report.

  3. 29 CFR 1926.1127 - Cadmium.

    Science.gov (United States)

    2010-07-01

    ... containment of cadmium or materials containing cadmium on the site or location at which construction...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1127 Cadmium. (a... forms, in all construction work where an employee may potentially be exposed to cadmium....

  4. Cadmium exposure in the Swedish environment

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    This report gives a thorough description of cadmium in the Swedish environment. It comprises three parts: Cadmium in Sweden - environmental risks;, Cadmium in goods - contribution to environmental exposure;, and Cadmium in fertilizers, soil, crops and foods - the Swedish situation. Separate abstracts have been prepared for all three parts

  5. Indicator minerals as guides to base metal sulphide mineralisation in Betul Belt, central India

    Indian Academy of Sciences (India)

    Biswajit Ghosh; M N Praveen

    2008-08-01

    Zn-bearing minerals that act as indicator minerals for base metal sulphide mineralization from the Proterozoic Betul Belt,central India with special emphasis on their genetic significance have been discussed.Sulphide mineralisation is hosted by the felsic volcanic rocks and has similarities with volcanic-hosted massive sulphide deposits in other parts of the world.Synvolcanic hydrothermal alteration is crudely zoned with an inner high Mg-Ca core and an outer wider envelop of Al-Fe rich mineral assemblage.Most of the prospects have strata bound,moderately to steeply dipping, multiple,sub-parallel sheet like ore bodies composed of disseminated and semi-massive to massive ores.Zn-bearing spinel,staurolite,biotite and ilmenite typically occur within the foot-wall altera- tion zones in close proximity to the sulphide mineralization.Zincian spinel is ubiquitous irrespective of the nature of alteration zone.Zincian staurolite is nearly absent in Mg-Ca alteration zones but commonly present in Al-Fe alteration zone along with zincian ilmenite.Zn-bearing biotite in intimate association with zincian spinel is generally found in Mg-Ca alteration zone and in the transition to Al-Fe alteration zone.Most of these indicator minerals can be considered as products of desulphidation of sphalerite during metamorphism.Mechanisms other than desulphidation like formation of gahnite by overstepping of the zinc saturation limit of biotite during retrogression to chlorite and formation of zincian staurolite at the expense of gahnite is also recorded.Field presence of these minerals has immense significance in exploration in Betul Belt as they occur in close spatial relationship with the sulphide rich zones and therefore act as direct vectors to ore.

  6. The mineralogy and geochemistry of the copper lead and zinc sulphides of the Otavi Mountainland

    International Nuclear Information System (INIS)

    A study of 44 samples from the area revealed that the major primary sulphides, which constitute the bulk of the mineralization, are galena, sphalerite, chalcopyrite, and tennantite. The copper mineralization is concentrated in the Huttenberg Formation of the Tsumeb Subgroup and in the Nosib Subgroup, and the lead and zinc mineralization mainly in the Berg Aukas, Gauss, Auros, Maieberg, and Elandshoek Formations of the Otavi Group. Antimony, manganese, and silver were detected in all the samples of galena analysed, and selenium in four deposits. Silver, iron, and zinc were found within tennantite exsolutions in sphalerite. The concentrations of these minor and trace elements are probably too low to affect the economic potential of any of the deposits. Manganese was also observed in samples of sphalerite, which were found to vary in colour according to their manganese content, being dark red when the manganese content is high and ranging through orange to yellow as the manganese content decreases.The deposits of the Otavi Mountainland are similar in many ways to deposits of the Mississippi Valley type, and a similar genesis is proposed for the Mountainland. It is sugessted that the genesis involved the deposition of sediments and chemical deposits in the Swakop Basin, the leaching of the contained metals from the clay particles by the fluid trapped in the sediments, and the transportation of these metals in brine solutions. Bacterial action resulted in the formation of hydrogen sulphide, which was then trapped in the solutions. Bacterial action resulted in the formation of hydrogen sulphide, which was then trapped in the carbonates and later released when the dolomitic rocks of the area were subjected to folding, faulting, and brecciation. On its release, the hydrogen sulphide reacted with the brine solutions to form sulphide deposits in the fault and breccia zones

  7. 2D X-ray and FTIR micro-analysis of the degradation of cadmium yellow pigment in paintings of Henri Matisse

    International Nuclear Information System (INIS)

    The chemical and physical alterations of cadmium yellow (CdS) paints in Henri Matisse's The Joy of Life (1905-1906, The Barnes Foundation) have been recognized since 2006, when a survey by portable X-ray fluorescence identified this pigment in all altered regions of the monumental painting. This alteration is visible as fading, discoloration, chalking, flaking, and spalling of several regions of light to medium yellow paint. Since that time, synchrotron radiation-based techniques including elemental and spectroscopic imaging, as well as X-ray scattering have been employed to locate and identify the alteration products observed in this and related works by Henri Matisse. This information is necessary to formulate one or multiple mechanisms for degradation of Matisse's paints from this period, and thus ensure proper environmental conditions for the storage and the display of his works. This paper focuses on 2D full-field X-ray Near Edge Structure imaging, 2D micro-X-ray Diffraction, X-ray Fluorescence, and Fourier Transform Infra-red imaging of the altered paint layers to address one of the long-standing questions about cadmium yellow alteration - the roles of cadmium carbonates and cadmium sulphates found in the altered paint layers. These compounds have often been assumed to be photo-oxidation products, but could also be residual starting reagents from an indirect wet process synthesis of CdS. The data presented here allow identifying and mapping the location of cadmium carbonates, cadmium chlorides, cadmium oxalates, cadmium sulphates, and cadmium sulphides in thin sections of altered cadmium yellow paints from The Joy of Life and Matisse's Flower Piece (1906, The Barnes Foundation). Distribution of various cadmium compounds confirms that cadmium carbonates and sulphates are photo-degradation products in The Joy of Life, whereas in Flower Piece, cadmium carbonates appear to have been a [(partially) unreacted] starting reagent for the yellow paint, a

  8. 2D X-ray and FTIR micro-analysis of the degradation of cadmium yellow pigment in paintings of Henri Matisse

    Energy Technology Data Exchange (ETDEWEB)

    Pouyet, E. [European Synchrotron Radiation Facility, Grenoble (France); ARC-Nucleart - CEA/Grenoble, Grenoble Cedex 9 (France); Cotte, M. [European Synchrotron Radiation Facility, Grenoble (France); LAMS (Laboratoire d' Archeologie Moleculaire et Structurale) UMR-8220, Ivry-sur-Seine (France); Fayard, B.; Salome, M.; Kieffer, J.; Burghammer, M.; Sette, F. [European Synchrotron Radiation Facility, Grenoble (France); Meirer, F. [Utrecht University, Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht (Netherlands); Mehta, A. [SLAC National Accelerator Laboratory, Stanford Synchrotron radiation Lightsource, Menlo Park, CA (United States); Uffelman, E.S. [Washington and Lee University, Department of Chemistry and Biochemistry, Lexington, VA (United States); Hull, A. [University of Delaware, Department of Chemistry and Biochemistry, Newark, DE (United States); Vanmeert, F.; Janssens, K. [University of Antwerp, AXES Research Group, Department of Chemistry, Antwerp (Belgium); Mass, J. [Winterthur Museum, Scientific Research and Analysis Laboratory, Conservation Department, Winterthur, DE (United States)

    2015-11-15

    The chemical and physical alterations of cadmium yellow (CdS) paints in Henri Matisse's The Joy of Life (1905-1906, The Barnes Foundation) have been recognized since 2006, when a survey by portable X-ray fluorescence identified this pigment in all altered regions of the monumental painting. This alteration is visible as fading, discoloration, chalking, flaking, and spalling of several regions of light to medium yellow paint. Since that time, synchrotron radiation-based techniques including elemental and spectroscopic imaging, as well as X-ray scattering have been employed to locate and identify the alteration products observed in this and related works by Henri Matisse. This information is necessary to formulate one or multiple mechanisms for degradation of Matisse's paints from this period, and thus ensure proper environmental conditions for the storage and the display of his works. This paper focuses on 2D full-field X-ray Near Edge Structure imaging, 2D micro-X-ray Diffraction, X-ray Fluorescence, and Fourier Transform Infra-red imaging of the altered paint layers to address one of the long-standing questions about cadmium yellow alteration - the roles of cadmium carbonates and cadmium sulphates found in the altered paint layers. These compounds have often been assumed to be photo-oxidation products, but could also be residual starting reagents from an indirect wet process synthesis of CdS. The data presented here allow identifying and mapping the location of cadmium carbonates, cadmium chlorides, cadmium oxalates, cadmium sulphates, and cadmium sulphides in thin sections of altered cadmium yellow paints from The Joy of Life and Matisse's Flower Piece (1906, The Barnes Foundation). Distribution of various cadmium compounds confirms that cadmium carbonates and sulphates are photo-degradation products in The Joy of Life, whereas in Flower Piece, cadmium carbonates appear to have been a [(partially) unreacted] starting reagent for the yellow paint, a

  9. Cadmium in newborns

    OpenAIRE

    Eklund, Gunilla

    2003-01-01

    Cadmium (Cd) is a well-known nephrotoxic environmental contaminant but there are indications that the developing nervous system might be even more sensitive to Cd than the kidneys in adults. Infants are exposed to Cd from various formulas and infant diets and the gastrointestinal Cd uptake is believed to be higher in newborns than in adults. Cd levels monitored in infant foods ranged between 0.74 and 27.0 µg/kg. Cow's milk formulas had the lowest levels and cereal-based formulas had up to 21 ...

  10. Utilisation of X-Ray computed microtomography for evaluation of iron sulphide distribution in roofing slate

    Science.gov (United States)

    Souček, Kamil; Daněk, Tomáš; Vavro, Martin; Botula, Jiří

    2016-04-01

    Roofing slate represents a traditional natural stone used for centuries for roofing and other construction applications in various types of buildings. Quality roofing slate must be primarily splittable into large, thin and waterproof tiles. In addition, it must be stable in colour and resistant against weathering. The abundance of mineral phases that weather easily or minerals that are long-term unstable has the effect of reducing the durability of slates in exterior conditions. One of the most problematic rock components, which are in a larger or smaller extent present in almost all slates, are iron sulphides, such as pyrite, marcasite or pyrrhotite. Under common atmospheric conditions, these minerals tend to oxidise, which leads to the formation of limonite and sulphuric acid. As a consequence of the origin of red-brown Fe oxyhydroxides, the undesirable colour changes of the slate may occur. But the most serious problem which occurs during this process is the changes in volume. This can cause disintegration of slate depending on the form of the iron sulphide occurrence. The content and size distribution of iron sulphides in roofing slate is normally determined using the microscopic analysis in transmitted light, combined with the observation in reflected light. For quantitative determination of iron sulphides in slate, the X-Ray powder diffraction is also often used. The results of the microscopic and X-Ray analyses need to be mutually compared and should not differ fundamentally. This paper is focused on the assessing the possibility of application of the X-Ray computed microtomography (CT) as a new complementary technique enabling the analysis of content and size (volume) distribution of iron sulphides in roofing slate. The X-Ray CT study was conducted using an XT H 225 ST industrial micro-tomographic system made by Nikon Metrology NV. Studied samples were reconstructed using the CT Pro 3D software (Nikon Metrology NV). The visualisation and analysis software

  11. Cadmium immobilization by hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Smičiklas Ivana D.

    2003-01-01

    Full Text Available The contamination of air, soil and water by cadmium is a great environmental problem. If cadmium occurs in nature in ionic form, soluble in water, it easily enters into the food chain. Hydroxyapatite (HAP, Ca-o(POAe(OH2 is a sparingly soluble salt and an excellent matrix for the removal of heavy metals from solutions. Considerable research attention has been paid to the bond between Cc/2+ ions and synthetic hydroxyapatite of known composition. The sorption mechanism is complex. The dominant process is ion exchange, but surface adsorption, surface complexation and coprecipitation can also contribute to the overall mechanism. The sorption capacity depends on the characteristics of hydroxyapatite itself and on the experimental conditions. Under optimum conditions a maximum capacity of 0.8 mol Cd2+/mol HAP can be achieved. HAP is a potential sorbent for the remediation of contaminated water and soil, for industrial waste treatment, and it is also referenced as a material that can be used as a barrier around waste depositories.

  12. Visible photoluminescence of MWCNT/CdS nanohybrid structure synthesized by a simple chemical process

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Rima; Kumbhakar, P. [Department of Physics, National Institute of Technology, Mahatma Gandhi Avenue, Durgapur 713209, West Bengal (India); Mitra, A.K., E-mail: akmrecdgp@yahoo.co [Department of Physics, National Institute of Technology, Mahatma Gandhi Avenue, Durgapur 713209, West Bengal (India)

    2010-03-15

    The authors report a simple wet chemical technique to prepare hybrid nanostructures of multiwalled carbon nanotubes (MWCNT) and cadmium sulphide (CdS) nanoparticles. In a solution containing cadmium acetate and sodium sulphide, purified MWCNTs are added. Cadmium sulphide nanocrystals of average size 5 nm are synthesized and they decorate the walls of the MWCNTs. The hybrid material is characterized by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and Raman spectroscopy. Interesting optical properties of the composite are revealed through UV-vis and photoluminescence (PL) spectroscopy.

  13. Cadmium(2) complexes of cytosine

    International Nuclear Information System (INIS)

    Complexes of cadmium(2) with cytosine obtained from aqueous or physiological solutions at room temperature are reported. The complexes were characterized by spectroscopic, conductometric, 1H-NMR, and 13C-NMR measurements and also by thermogravimetry. (Authors)

  14. Discovery of the Cadmium Isotopes

    OpenAIRE

    Amos, S.; Thoennessen, M

    2009-01-01

    Thirty-seven cadmium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  15. Characterization and HDS activities of mixed Fe-Mo sulphides supported on alumina and carbon

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hubaut; Jonathan Altafulla; Alain Rives; Carlos Scott [Universite des Sciences et des Technologies de Lille, Villeneuve d' Ascq (France). Unite de Catalyse et de Chimie du Solide

    2007-03-15

    Alumina and activated carbon-supported mixed sulphides (FeMoS) were prepared as hydrotreating catalysts. Previous work had shown bulk Fe-Mo mixed sulphides to be promising catalysts for hydrotreatment. Characterizations of the solids by NH{sub 3}-TPD proved to be a good technique to classify the solids according to their acidic strength. Thiophene hydrodesulphurization (HDS) and High vacuum gas oil (HVGO) hydrotreatment, performed at atmospheric pressure and high pressure respectively, were used as catalytic tests. Depending on the support, a more or less important synergetic effect is observed. The results are in agreement with a possible direct desulphurization process. The acidic strength plays an important role in determining the hydrogenolysis/hydrogenation ratio of the catalysts. 26 refs., 4 figs., 9 tabs.

  16. The physics analysis and experiment study of zinc sulphide scintillator for fast neutron radiography

    International Nuclear Information System (INIS)

    Fast neutron radiography is a promising application for accelerator based neutron sources. The potential effectiveness of this technique depends on the development of suitable imaging detectors for fast neutrons. Zinc sulphide based scintillators have the largest light output per event in the family of imaging scintillators used so far in fast neutron radiography. This paper investigated different aspects of this scintillator in order to determine the factors which might affect the light output. A mathematical model was established to estimate effectiveness of this scintillator. Zinc sulphide screens were prepared with ZnS particles of different concentrations in polypropylene matrix. A 14 MeV fast neutron source was used in the experiments. The light output was detected using a CCD camera or a film coupled to the scintillator screen. The results showed that the optimum scintillators is around 3 mm in thickness with the weight ratio of 2:1 for ZnS and polypropylene

  17. Comparative study on the passivation layers of copper sulphide minerals during bioleaching

    Science.gov (United States)

    Fu, Kai-bin; Lin, Hai; Mo, Xiao-lan; Wang, Han; Wen, Hong-wei; Wen, Zi-long

    2012-10-01

    The bioleaching of copper sulphide minerals was investigated by using A. ferrooxidans ATF6. The result shows the preferential order of the minerals bioleaching as djurleite>bornite>pyritic chalcopyrite>covellite>porphyry chalcopyrite. The residues were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is indicated that jarosite may not be responsible for hindered dissolution. The elemental sulfur layer on the surface of pyritic chalcopyrite residues is cracked. The compact surface layer of porphyry chalcopyrite may strongly hinder copper extraction. X-ray photoelectron spectroscopy (XPS) further confirms that the passivation layers of covellite, pyritic chalcopyrite, and porphyry chalcopyrite are copper-depleted sulphide Cu4S11, S8, and copper-rich iron-deficient polysulphide Cu4Fe2S9, respectively. The ability of these passivation layers was found as Cu4Fe2S9>Cu4S11>S8>jarosite.

  18. Cadmium telluride nuclear radiation detectors

    International Nuclear Information System (INIS)

    The characteristics and performance of undoped high resistivity cadmium telluride detectors are compared to chlorine lifted counters. It is shown, in particular, that Undodep CdTe is in fact aluminium doped and that compensation occurs, as an silicon or germanium, by pair and triplet formation between the group III donor and the doubly charged cadmium vacancy acceptor. Furthermore, in chlorine doped samples, the polarization effect results from the unpaired level at Esub(c)-0,6eV

  19. Speciation of Dissolved Cadmium

    DEFF Research Database (Denmark)

    Holm, Peter Engelund; Andersen, Sjur; Christensen, Thomas Højlund

    1995-01-01

    ) method separates dissolved Cd into free divalent Cd (Cd 2+) and complexed Cd and furthermore separates the latter into the operationally defined forms: labile, slowly labile and stable complexes. The dialysis (ED) method determines high molecular weight Cd complexes (above 1000mol. wt). For both methods...... the reproducibility was good. By combining the results of the GEOCHEM calculations in terms of the inorganic complexes, and the IE results, the fractions of free and inorganically complexed Cd were estimated. The IE and ED results furthermore provided information about the organic complexes. Selected environmental......Equilibrium dialysis and ion exchange methods, as well as computer calculations (GEOCHEM), were applied for speciation of dissolved cadmium (Cd) in test solutions and leachate samples. The leachate samples originated from soil, compost, landfill waste and industrial waste. The ion exchange (IE...

  20. MATHEMATICAL OPTIMIZATION METHODS TO ESTABLISH ACTIVE PHASES ON HETEROGENEOUS CATALYSIS: CASE OF BULK TRANSITION METAL SULPHIDES

    Directory of Open Access Journals (Sweden)

    Iván Machín

    2015-03-01

    Full Text Available This paper presents a set of procedures based on mathematical optimization methods to establish optimal active sulphide phases with higher HDS activity. This paper proposes a list of active phases as a guide for orienting the experimental work in the search of new catalysts that permit optimize the HDS process. Studies in this paper establish Co-S, Cr-S, Nb-S and Ni-S systems have the greatest potential to improve HDS activity.

  1. Hydrodesulphurization of thiophene by transition metal sulphides. A molecular orbital topology study

    Science.gov (United States)

    Smit, T. S.; Johnson, K. H.

    1993-09-01

    Transition metal sulphides have the ability to catalyze the hydrodesulphurization (HDS) process of thiophene and related compounds in the presence of hydrogen. We present the results of scattered-wave calculations on model catalyst clusters and catalyst—thiophene complexes, which indicate that pπ bonding, between the sulphur atoms in the catalyst and the sulphur and carbon atoms in the thiophene ring, is responsible for binding the thiophene molecule to the catalyst in the initial stages of the HDS process.

  2. The determination of some trace elements in sulphide concentrates by spectrophotometry

    International Nuclear Information System (INIS)

    The report describes the determination of trace amounts (as low as 1 to 10 p.p.m. depending on the element) of arsenic, germanium, molybdenum, nickel, phosphorus, selenium, tellurium, tin, and titanium in sulphide concentrates. The proposed methods, which are detailed in the appendices, are adaptations of established procedures that were modified to allow for the complex nature of the concentrates to be analysed

  3. Photocatalytic degradation of rose Bengal by semiconducting zinc sulphide used as a photocatalyst

    Directory of Open Access Journals (Sweden)

    Sharma Shweta

    2013-01-01

    Full Text Available Various semiconductors have been used as photocatalysts for removal of different dyes from their aqueous solutions. Zinc sulphide semiconductor is used in the present investigation as a photocatalyst for the removal of rose Bengal dye. Effect of different parameters, which affect the rate of reaction; like pH, concentration of dye, amount of semiconductor and light intensity have been studied. A mechanism has also been proposed in which hydroxyl radicals are shown as an active oxidizing species.

  4. Recent Advance in the Electrochemical Detection of Sulphide and Sulphhydryl Species

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This article aims at providing a critical review of some most recent developments in the electrochemical detection and measurement of hydrogen sulphide and the related species, which are of great significance to a variety of industries and in environmental moitoring. The molecular recognition processes are initiated by using either an organic precursor or a catalytic complex, leading to extensive ranges of detection. A series of advanced chemical and simulation techniques are used to probe the mechanistic details of the analytical chemistry involved.

  5. Studies on gas-liquid mass transfer in atmospheric leaching of sulphidic zinc concentrates

    OpenAIRE

    Kaskiala, Toni

    2005-01-01

    In this work, the mass transfer of oxygen in the atmospheric leaching process of zinc sulphide was investigated. Four new experimental apparatus items suitable for this purpose were designed and developed. The experiments conducted with the water model were focused on volumetric mass transfer, gas and liquid flow patterns, gas dispersion and bubble size. The effects of liquid properties and temperature on bubble size were examined with the bubble swarm system. Mass transfer coefficients, kL, ...

  6. A fundamental investigation into the microwave assisted leaching of sulphide minerals

    OpenAIRE

    Al-Harahsheh, Mohammad

    2005-01-01

    Microwave assisted leaching has been investigated in an attempt to improve both the yield of extracted metal and reduce processing time. This is especially pertinent in view of the increased demands for metal and more environmentally friendly processes. This work reports a fundamental study on the influence of microwave energy on the dissolution of sulphide minerals. Chalcopyrite and sphalerite were chosen as model materials due to their economic importance and the diversity of their hea...

  7. Towards the development of poly (phenylene sulphide) based nanocomposites with enhanced mechanical, electrical and tribological properties

    OpenAIRE

    Díez Pascual, Ana María; Naffakh Cherradi Hadi, Mohammed

    2012-01-01

    Novel poly(phenylene sulphide) (PPS) nanocomposites reinforced with an aminated derivative (PPS-NH2) covalently attached to acid-treated single-walled carbon nanotubes (SWCNTs) were prepared via simple melt-blending technique. Their morphology, viscoelastic behaviour, electrical conductivity, mechanical and tribological properties were investigated. Scanning electron microscopy revealed that the grafting process was effective in uniformly dispersing the SWCNTs within the matrix. The storage a...

  8. Effects of Annealing on Structural Properties of Copper Zinc Tin Sulphide (CZTS) Material

    OpenAIRE

    K.K. Patel; D.V. Shah; Vipul Kheraj

    2013-01-01

    Copper Zinc Tin Sulphide compound was synthesized from its elemetal precursurs using simple solid state method. Being quarternary material, there is a large probability of formation of secondary phases like SnS, ZnS, CuS during the material growth process and it requires a detail investigation on the effects of synthesis parameters on the composition and structural properties of the CZTS compound. Here we report the study of effects of annealing on the synthesized compound. The annealing was ...

  9. APPLICATION OF METHODS OF BACTERIAL LEACHING FOR GOLD-SULPHIDE ORES OF UZBEKISTAN

    OpenAIRE

    Zaynitdinova, Lyudmila; Kukanova, Svetlana; Aripov, Tahir

    2014-01-01

    Possibility of application of bacterial leaching for ores of Kokpatas deposit was established. It was determined that at heap bioleaching of ores during 150 days sulphides are oxidized to 80-87% and extraction of gold reaches 70%. Synthetic polymer on basis of polyvinylpyrrolidone (P-1) was used for intensification of the process of bioleaching and its application promoted to additional 8-10% of gold extraction.

  10. Vanadium-Doped In and Sn Sulphides: Photocatalysts able to use the whole visible light spectrum

    OpenAIRE

    Lucena, Raquel; Fresno, Fernando; Conesa, Jose Carlos; Palacios Clemente, Pablo; Seminóvski Pérez, Yohanna; Wahnón Benarroch, Perla

    2012-01-01

    Using photocatalysis for energy applications depends, more than for environmental purposes or selective chemical synthesis, on converting as much of the solar spectrum as possible; the best photocatalyst, titania, is far from this. Many efforts are pursued to use better that spectrum in photocatalysis, by doping titania or using other materials (mainly oxides, nitrides and sulphides) to obtain a lower bandgap, even if this means decreasing the chemical potential of the electron-hole pairs. He...

  11. Hydrogen sulphide and mild hypothermia activate the CREB signaling pathway and prevent ischemia-reperfusion injury

    OpenAIRE

    Dai, Hai-bin; Ji, Xiangjun; Zhu, Si-Hai; Hu, Yi-min; Zhang, Li-dong; Miao, Xiao-lei; Ma, Ru-Meng; Duan, Man-lin; Li, Wei-Yan

    2015-01-01

    Background Both hydrogen sulphide (H2S) and mild hypothermia have been reported to prevent brain damage caused by reperfusion assault through regulating the N-methyl-D-aspartate receptor (NMDAR). However, the relationship between the two treatments and how they exert neuro-protective effects through NMDARs remain to be elucidated. Methods Transient cerebral ischemia was induced using the Pulsinelli four-vessel occlusion method. We used sodium hydrosulphide (NaHS) as the H2S donor. We randomly...

  12. Sulphidization flotation for recovery of lead and zinc from oxide-sulfide ores

    Institute of Scientific and Technical Information of China (English)

    FA Keqing; Jan D.Miller; JIANG Tao; LI Guang-hui

    2005-01-01

    A new flowsheet was developed to recover the valuable minerals from oxide or oxide-sulfide ores of lead and zinc. The flowsheet consisted of flotation of sulfide minerals, desliming and sulphidization-flotation of oxide minerals. The corresponding reagent system and techniques to the flowsheet were investigated. Batch and continuous tests show that the dosage of sodium sulfide, temperature, and collector type are main affecting factors on the recovery of smithsonite and cerussite. For the flotation of cerussite, there is an appropriate dosage of sodium sulfide at which the recovery reaches its maximum value. The required sodium sulfide for smithsonite flotation is higher than that for cerussite and the recovery of smithsonite flotation increases with the dosage of sodium sulfide at low level and becomes insensitive at high dosage. The appropriate temperature for smithsonite and cerussite flotation is found to be 25 - 40 ℃. Amines are found to be the effective collectors for the flotation of smithsonite after sulphidization. Investigation also shows that desliming prior to sulphidization-flotation is essential to the effective recovery of smithsonite and cerussite, and the desliming process of two-stage hydrocyclon is well feasible and effective for the treatment of lead-zinc oxide ores. A further treatment on the cerussite flotation concentrate by shaking table is proposed to obtain higher lead grade.

  13. Lattice Dynamics at Zone-Center of Sulphide and Selenide Spinels

    Institute of Scientific and Technical Information of China (English)

    A.K. Kushwaha

    2008-01-01

    A rigid-ion model is used to calculate the force constants and effective dynamical charges of sulphide and selenide spinels. The Raman and infrared phonon modes of normal cubic sulphide spinels MCr2S4 (M=Mn, Co, Fe, Hg, Zn, and Cd) and selenide spinels MCr2Se4 (M=Hg, Zn, and Cd) are calculated at the first Brillouin zone-centre using above model. The significant outcome of the present work is (I) the interatomic interaction between Cr-S (Se) dominates over the Cr-S(Se) and S-S(Se-Se) type of interatomic interactions, (ii) the effective dynamical charges of the bivalent metal ions are nearly zero, and (ⅲ) the selenide spinels are less ionic than the sulphide spinels and the ionicity decreases as MnCr2S4 FeCr2S4 CoCr2S4 > and CdCr2C4 > ZnCr2C4 > HgCr2C4 (C=S and Se). The zone-center phonon frequencies, calculated using these parameters, are found to be in very good agreement with the observed results.

  14. Sulphide mineral evolution and metal mobility during alteration of the oceanic crust: Insights from ODP Hole 1256D

    Science.gov (United States)

    Patten, C. G. C.; Pitcairn, I. K.; Teagle, D. A. H.; Harris, M.

    2016-11-01

    Fluxes of metals during the hydrothermal alteration of the oceanic crust have far reaching effects including buffering of the compositions of the ocean and lithosphere, supporting microbial life and the formation of sulphide ore deposits. The mechanisms responsible for metal mobilisation during the evolution of the oceanic crust are complex and are neither fully constrained nor quantified. Investigations into the mineral reactions that release metals, such as sulphide leaching, would generate better understanding of the controls on metal mobility in the oceanic crust. We investigate the sulphide and oxide mineral paragenesis and the extent to which these minerals control the metal budget in samples from Ocean Drilling Program (ODP) Hole 1256D. The ODP Hole 1256D drill core provides a unique sample suite representative of a complete section of a fast-spreading oceanic crust from the volcanic section down to the plutonic complex. The sulphide population at Hole 1256D is divided into five groups based on mineralogical assemblage, lithological location and texture: the magmatic, metasomatised, high temperature hydrothermal, low temperature and patchy sulphides. The initiation of hydrothermal alteration by downward flow of moderate temperature (250-350 °C) hydrothermal fluids under oxidising conditions leads to metasomatism of the magmatic sulphides in the sheeted dyke and plutonic complexes. Subsequent increase in the degree of hydrothermal alteration at temperatures >350 °C under reducing conditions then leads to the leaching of the metasomatised sulphides by rising hydrothermal fluids. Mass balance calculations show that the mobility of Cu, Se and Au occurs through sulphide leaching during high temperature hydrothermal alteration and that the mobility of Zn, As, Sb and Pb is controlled by silicate rather than sulphide alteration. Sulphide leaching is not complete at Hole 1256D and more advanced alteration would mobilise greater masses of metals. Alteration of oxide

  15. Experimental study of Ni solubility in sulphidic groundwater and cement water under anoxic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, T.; Vuorinen, U.; Kekki, T.; Aalto, H. [VTT Chemical Technology, Espoo (Finland)

    2001-06-01

    The nickel solubility was studied during a 177-day period under anoxic conditions in three types of waters: a synthetic reference groundwater (OL-SR), a natural Olkiluoto groundwater (PVA2), and a cement-conditioned groundwater (C-PVA2). To each water, nickel, ferrous iron and sulphide were added yielding eight combinations of, approximately, the following initial concentrations: nickel: 1.0x10{sup -6} and 1.0x10{sup -3} mol/L, ferrous iron: 1.8 10{sup -6} and 1.8x10{sup -5} mol/L, and sulphide: 3.1x10{sup -6} and 9.4x10{sup -5} mol/L. The concentrations of these elements in the natural groundwater PVA2 as well as in the cement-conditioned water C-PVA2 was insignificant. In the synthetic water, the nickel concentration was unchanged in all samples having a high initial nickel concentration of 1.0x10{sup -3} mol/L. In the samples with an initial low nickel concentration of 1.0x10{sup -6} mol/L, the sulphide content determined the final nickel concentration. Where the initial sulphide concentration was low, the nickel concentration remained at the level of 1.0x10{sup -6} mol/L, but the higher sulphide concentration caused the nickel concentration to drop to below 10{sup -8} mol/L. In the natural groundwater PVA2, the nickel concentration dropped to below 10{sup -4} mol/L in all samples with an initially high nickel concentration, and to values of roughly 10{sup -7} mol/L in samples with an initially low nickel content. In the cement-conditioned water, the nickel concentration reached a value of 3x10{sup -6} mol/L in samples with initial high nickel concentrations, and to a value of 1x10{sup -7} mol/L in samples with a low initial nickel content. The added amounts of iron and sulphide did not have any significant effect on the observed nickel solubility. The solid phases formed in the natural and synthetic groundwater were analyzed by XRD but could not be identified. In the case of cement-conditioned water the XRD analyses showed the presence of Ni(OH){sub 2} as well

  16. Zinc-induced protection against cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Early, J.L.; Schnell, R.C.

    1978-02-01

    Pretreatment of male rats with cadmium acetate potentiates the duration of hexobarbital hypnosis and inhibits the rate of hepatic microsomal drug metabolism. Pretreatment of rats with zinc acetate protects against these alterations in drug action elicited by cadmium.

  17. Ecotoxicity of engineered nanoparticles to freshwater organisms

    DEFF Research Database (Denmark)

    Hartmann, Nanna Isabella Bloch

    in areas as diverse as cancer treatment, groundwater remediation and industrial coatings. Nanoparticles are used to give the products new and improved characteristics. Yet exactly these new and nano-specific properties might be a cause of concern in a health and environment context. In order to ensure...... for interaction scenarios between nanoparticles and co-existing environmental pollutants was developed. Experimental results showed that several types of nanoparticles (e.g. TiO2 and C60) have a large adsorption capacity for some heavy metals and organic chemicals. Nonetheless, cadmium adsorbed to TiO2...

  18. Bioavailability of cadmium from linseed and cocoa

    DEFF Research Database (Denmark)

    Hansen, Max; Sloth, Jens Jørgen; Rasmussen, Rie Romme

    In Denmark and EU the exposure of cadmium from food is at a level that is relatively close to the Tolerable Daily Intake (TDI). This report describes an investigation of the bioavailability of cadmium in selected food items known to contain high levels of cadmium. The purpose was to provide data ...... or crushed linseed nor the intake of cocoa and chocolate....

  19. Effects of sulphide ion on the corrosion behaviour of X52 steel in a carbon dioxide environment at temperature 40 deg. C

    International Nuclear Information System (INIS)

    Research highlights: → We study the effect of sulphide ion on the corrosion behaviour of X52 steel. → Increasing sulphide ion concentration will increase the corrosion rate of X52 steel. → Increasing sulphide ion concentration will increase cathodic reaction. → Less protective film, also contribute to the increasing the corrosion rate. - Abstract: The electrochemical behaviour of X52 steel in the presence of sulphide at 40 deg. C in a CO2 environment was investigated using the methods of linear polarization resistance (LPR), potentiodynamic sweep, electrochemical impedance spectroscopy (EIS). In addition, the surface of X52 steel was also studied using scanning electron microscopy (SEM). The results showed that the corrosion rate of X52 steel increased with increasing concentration of sulphide ion. Potentiodynamic curve showed that there were changes in cathodic branch due to the change in the nature of cathodic reaction in the presence of sulphide ion. EIS analysis showed the higher sulphide ion concentration, the higher adsorbed species on the steel surface that contributed in the cathodic reaction. Furthermore, SEM results showed crevices on the scale which indicated pitting tendency in sulphide ion solutions. The less protective film, probably mackinawite, also contributed to the increase of corrosion rate in the presence of sulphide ion.

  20. Mechanisms of cadmium carcinogenesis

    International Nuclear Information System (INIS)

    Cadmium (Cd), a heavy metal of considerable occupational and environmental concern, has been classified as a human carcinogen by the International Agency for Research on Cancer (IARC). The carcinogenic potential of Cd as well as the mechanisms underlying carcinogenesis following exposure to Cd has been studied using in vitro cell culture and in vivo animal models. Exposure of cells to Cd results in their transformation. Administration of Cd in animals results in tumors of multiple organs/tissues. Also, a causal relationship has been noticed between exposure to Cd and the incidence of lung cancer in human. It has been demonstrated that Cd induces cancer by multiple mechanisms and the most important among them are aberrant gene expression, inhibition of DNA damage repair, induction of oxidative stress, and inhibition of apoptosis. The available evidence indicates that, perhaps, oxidative stress plays a central role in Cd carcinogenesis because of its involvement in Cd-induced aberrant gene expression, inhibition of DNA damage repair, and apoptosis.

  1. Oral cadmium chloride intoxication in mice

    DEFF Research Database (Denmark)

    Andersen, O; Nielsen, J B; Svendsen, P

    1988-01-01

    Diethyldithiocarbamate (DDC) is known to alleviate acute toxicity due to injection of cadmium salts. However, when cadmium chloride was administered by the oral route, DDC enhanced rather than alleviated the acute toxicity; both oral and intraperitoneal (i.p.) administration of DDC had this effect....... Thus, orally administered DDC enhanced cadmium-induced duodenal and ileal tissue damage and inhibition of peristalsis, as indicated by an increased intestinal transit time. At low cadmium doses, the whole-body retention of cadmium was increased by oral DDC administration. Intraperitoneally administered...

  2. Production of activated carbon and its catalytic application for oxidation of hydrogen sulphide

    Science.gov (United States)

    Azargohar, Ramin

    Hydrogen sulphide is an environmentally hazardous gas which is present in many gas streams associated with oil and gas industry. Oxidation of H 2S to sulphur in air produces no bulky or waste material and requires no further purification. Activated carbon is known as a catalyst for this reaction. In this research, a coal-based precursor (luscar char) and a biomass-based precursor (biochar) were used for production of activated carbons by two common methods of activation: physical and chemical activation in which steam and potassium hydroxide (KOH), respectively, were used. Experiments were designed by the statistical central composite design method. Two models were developed for the BET surface area and reaction yield of each activation process. These models showed the effects of operating conditions, such as activation temperature, mass ratio of activating agent to precursor, activation time, and nitrogen flowrate on the BET surface area and reaction yield for each activation method for each precursor. The optimum operating conditions were calculated using these models to produce activated carbons with relatively large BET surface area (> 500 m2/g) and high reaction yield (> 50 wt %). The BET surface area and reaction yield for activated carbons produced at optimum operating conditions showed maximum 7 and 7.4% difference, respectively, comparing to the values predicted by models. The activated carbons produced at optimum operating conditions were used as the base catalysts for the direct oxidation of 1 mol % hydrogen sulphide in nitrogen to sulphur at the temperature range of 160-205°C and pressure of 700 kPa. Originally activated carbons showed a good potential for oxidation of hydrogen sulphide by their selectivity for sulphur product and low amount of sulphur dioxide production. To improve the performance of steam-activated carbons, the catalysts were modified by acid-treatment followed by thermal desorption. This method increased the break-through times for

  3. Arsenic-cadmium interaction in rats.

    Science.gov (United States)

    Díaz-Barriga, F; Llamas, E; Mejía, J J; Carrizales, L; Santoyo, M E; Vega-Vega, L; Yáñez, L

    1990-11-01

    Simultaneous exposure to cadmium and arsenic is highly probable in the urban area of San Luis Potosi, Mexico due to common localization of copper and zinc smelters. Therefore, in this work, rats were intraperitoneally exposed either to cadmium or arsenic alone, or simultaneously to both metals. The effects of these treatments on three different toxicological parameters were studied. Cadmium modified the LD50 of arsenic and conversely arsenic modified the LD50 for cadmium. At the histopathological level, arsenic appeared to protect against the cadmium effects, especially on testes. This protective effect seemed to be related to the glutathione levels found in this tissue: rats exposed to both arsenic and cadmium, presented glutathione values intermediate to those observed after exposure to either metal alone; arsenic had the highest value and cadmium the lowest. In liver, rats exposed to arsenic, cadmium or arsenic and cadmium, presented glutathione values below those in the saline group, with the lowest value corresponding to the arsenic and cadmium treatment. The results appear to support the proposed interaction between arsenic and cadmium and coexposure to both metals seems to alter certain effects produced by either metal alone. PMID:2219140

  4. Determination of cadmium in biological samples.

    Science.gov (United States)

    Klotz, Katrin; Weistenhöfer, Wobbeke; Drexler, Hans

    2013-01-01

    Analyses of cadmium concentrations in biological material are performed using inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS), but also electrochemical methods, neutron activation analysis (NAA), and X-ray fluorescence spectrometry (XRF). The predominant sample matrices include blood, plasma, serum, and urine, as well as hair, saliva, and tissue of kidney cortex, lung, and liver. While cadmium in blood reveals rather the recent exposure situation, cadmium in urine reflects the body burden and is an indicator for the cumulative long term exposure.After chronic exposure, cadmium accumulates in the human body and causes kidney diseases, especially lesions of proximal tubular cells. A tubular proteinuria causes an increase in urinary excretion of microproteins. Excretions of retinol binding protein (RBP), β2-microglobulin (β2-M), and α1-microglobulin are validated biomarkers for analyzing cadmium effects. For this purpose, immunological procedures such as ELISA, and radio- and latex-immunoassays are used.However, proteinuria is not specific to cadmium, but can also occur after exposure to other nephrotoxic agents or due to various kidney diseases. In summary, cadmium in urine and blood are the most specific biomarkers of cadmium exposure. A combination of parameters of exposure (cadmium in blood, cadmium in urine) and parameters of effect (e.g., β2-M, RBP) is required to reveal cadmium-induced nephrological effects. PMID:23430771

  5. Insulin Expression in Rats Exposed to Cadmium

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objectives To investigate the effects of cadmium exposure on insulin expression in rats. Methods Eighteen adult SD assessed. The levels of cadmium and zinc in pancreas, blood and urine glucose, serum insulin and urine NAG (N-acyetyl-β-glucosaminidase) were determined. The gene expressions of metallothionein (MT) and insulin were also measured,and the oral glucose tolerance tests (OGTT) were carried out. Results The contents of cadmium in pancreas in cadmium-treated rats were higher than that in the control group, which was associated with slight increase of zinc in pancreas.not change significantly after cadmium administration, and the UNAG had no change in Cd-treated group. The gene expression the change of the expression of insulin, MT-Ⅰ and MT-Ⅱ genes. Cadmium can influence the biosynthesis of insulin, but does not induce the release of insulin. The dysfunction of pancreas occurs earlier than that of kidney after administration of cadmium.

  6. Determination of sulphide concentrates of ore copper by XRPD and chemical analysis

    OpenAIRE

    Cocić Mira B.; Logar Mihovil M.; Cocić Saša Lj.; Živković Dragana T.; Matović Branko Ž.; Dević Snežana S.

    2009-01-01

    Roasting process of sulphide copper concentrates in fluo-solid reactor is an oxidation process, and presents the first stage of copper concentrate processing in Copper Mining and Smelting Complex Bor, RTB Bor. Therefore, the importance of accurate and up to date process control is an apparent precondition for the correct treatment in the following stages and also for of high grade cathode copper. As concentrate is fed into the roaster, it is heated by a stream of hot air to about 590°C. The p...

  7. The determination, by atomic-absorption spectrophotometry, of trace elements in sulphide concentrates

    International Nuclear Information System (INIS)

    The separation, concentration, and determination of trace elements in base-metal and sulphide concentrates are described. After the sample has been dissolved, the trace elements that form insoluble hydroxides are precipitated with lanthanum as the coprecipitant and are separated from those elements that form soluble amines with ammonia. The precipitate is dissolved, and the trace elements selenium, tellurium, arsenic, antimony, bismuth, tin, vanadium, chromium, manganese, and aluminium are determined by atomic-absorption spectrophotometry. Coefficients of variation between 1 and 10 per cent, depending on the amount of the element, were obtained, with limits of determination ranging from 0,1 to 50 p.p.m

  8. Proton non-Rutherford backscattering study of oxidation kinetics in Cu and Fe sulphides

    Energy Technology Data Exchange (ETDEWEB)

    Chiari, M. [Padua Univ. (Italy). Dipt. di Fisica]|[INFN - Laboratori Nazionali di Legnaro, via Romea 4, 35020 Legnaro (Padova) (Italy); Giuntini, L. [INFN - Firenze, Largo Fermi 2, 50125 Firenze (Italy); Pratesi, G. [Museo di Mineralogia e Litologia, Universita di Firenze, via La Pira 4, 50121 Firenze (Italy); Santo, A.P. [Dipartimento di Scienze della Terra, Universita di Firenze, via La Pira 4, 50121 Firenze (Italy)

    1998-04-01

    Non-Rutherford backscattering spectrometry (NBS) with 2.4 MeV protons was performed for depth profiling of oxygen in three species of copper and iron sulphides - pyrite, chalcopyrite and bornite - on both altered and fresh surfaces. The tarnished surfaces were obtained by bathing samples in H{sub 2}O{sub 2} (35% vol.) for 100 and 1000 s. The spectra collected were compared to simulations to extract quantitative data on oxygen depth distributions for the different bathing times. The measurements have shown that the kinetics of oxidation has completely different patterns in the three investigated minerals. (orig.) 11 refs.

  9. Ultraviolet-visible absorption spectra of solid hydrogen sulphide under high pressure

    CERN Document Server

    Kume, T; Sasaki, S; Shimizu, H

    2002-01-01

    Ultraviolet-visible absorption spectra of solid hydrogen sulphide (H sub 2 S) were measured at various pressures from 0.3 to 29 GPa. The absorption edge observed around 4.8 eV at 0.3 GPa indicated a red-shift with increasing pressure, and positioned below 3 eV at 29 GPa. On the basis of the spectra obtained, the energy gap was determined as a function of pressure. The transition to phase IV at 11 GPa was found to lead to a small jump in its pressure dependence and to yield an Urbach tail in the absorption edge.

  10. Pressure-induced phase transition of nanocrystalline iron sulphide coated by polyvinyl alcohol

    CERN Document Server

    Gao Wei; Kan-Shihai; Pan Yue Wu; Wang Xin; Zou Guang Tian; LiuJing

    2002-01-01

    Nanocrystalline iron sulphide (FeS) coated with polyvinyl alcohol, with particle size ranging from several to several tens of nanometres, has been prepared by the chemical precipitation synthesis method. The phase transition of FeS has been investigated by using in situ high-pressure diffraction with synchrotron radiation at pressures up to 42.5 GPa. Most of the diffraction lines are broadened and weakened. At the pressure of 11.8 GPa, a new phase transition was observed. However, only eleven x-ray reflections were recorded under high pressure; the crystal structure is unknown.

  11. Tandem base-free synthesis of -hydroxy sulphides under ultrasound irradiation

    Indian Academy of Sciences (India)

    Guang-Shu Lv; Fu-Junduan; Jin-Chang Ding; Tian-Xing Cheng; Wen-Xia Gao; Jiu-Xi Chen; Hua-Yue Wu

    2012-09-01

    Rongalite® promotes cleavage of diaryl disulphides generating the corresponding thiolate species in situ which then undergo facile ring-opening of epoxides in a regioselective manner under ultrasound irradiation, affording -hydroxy sulphides in good to excellent yields. The important features of this methodology are base-free, odourless, high yield, reasonably rapid reaction rate, simple workup, high regioselectivity, costeffective and no requirement of transition metal catalysts. It is noteworthy that ring-opening reaction of 1,2-diphenyldiselane with 2-(phenoxymethyl)oxirane are also conducted smoothly to afford -hydroxy selenide in excellent yield under the standard conditions.

  12. Polycarboxylate derivative of -amino acid as growth modifier of sulphide minerals

    Indian Academy of Sciences (India)

    Harjyoti Thakuria; Gopal Das

    2011-02-01

    Construction of modified inorganic mineral with controlled mineralization analogues of those produced by nature is now of current interest for understanding the mechanism of the in vivo biomineralization processes, as well as looking for fresh industrial and technological applications. Low-molecular-weight chiral polycarboxylate ligands derived fromnaturally occurring -\\alpha-amino acids have been used asmodel systems to study the effect of small organic matrix on crystal growth modification. The sulphide minerals are characterized by PXRD, FT–IR and SEM. Furthermore, the optical properties of these minerals have been characterized by UV-Vis and photoluminescence (PL) spectra.

  13. Variability in abundance and fluxes of dimethyl sulphide in the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Shenoy, D.M.; DileepKumar, M.

    (University of Miami) and Dr. Gillian Malin (University of East Anglia) for their advice in regard to dimethyl sulphide analysis. Suggestions by the two anonymous reviewers helped improve this manuscript substantially. 16 References: Barnard, W.R., M... sulphur, cloud albedo and climate. Nature, 326, 655-661. Charlson, R.J., T.L. Anderson and R.E. McDuff, 1992. The Sulfur Cycle. In: Global Biogeochemical Cycles, S.S. Butcher, R.J. Charlson, G.H. Orians and G.V. Wolfe (eds), Academic Press, London...

  14. Studies on chemical bath deposited zinc sulphide thin films with special optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Ladar, Maria [Faculty of Chemistry and Chemical Engineering, ' Babes-Bolyai' University, 400028 Cluj-Napoca (Romania); ' Raluca Ripan' Institute for Research in Chemistry, 30 Fantanele, 400294 Cluj-Napoca (Romania); Popovici, Elisabeth-Jeanne [' Raluca Ripan' Institute for Research in Chemistry, 30 Fantanele, 400294 Cluj-Napoca (Romania)]. E-mail: jennypopovici@yahoo.com; Baldea, Ioan [Faculty of Chemistry and Chemical Engineering, ' Babes-Bolyai' University, 400028 Cluj-Napoca (Romania); Grecu, Rodica [' Raluca Ripan' Institute for Research in Chemistry, 30 Fantanele, 400294 Cluj-Napoca (Romania); Indrea, Emil [National Institute for R and D of Isotopic and Molecular Technology, Donath 71-103, 400293 Cluj-Napoca (Romania)

    2007-05-31

    Adherent and uniform zinc sulphide thin films were deposited on optical glass platelets from chemical bath containing thiourea, zinc acetate, ammonia and sodium citrate. The samples, as they were prepared were investigated by UV-vis absorption/reflection spectroscopy, fluorescence spectroscopy and X-ray diffraction. The effects of growth conditions such as reagent concentration and deposition technique (mono- and multi-layer) on optical and structural properties of the ZnS thin films have been studied. The ability of ZnS films to exhibit luminescent properties has also been investigated.

  15. Modification of Luminescent Properties of Red Sulphide Phosphors for White LED Lighting

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A kind of sulphide, CaS:Eu2+, activated by europium ion for white LED lighting was synthesized via solid-state reaction route in reducing atmospheres. The phosphors were then encapsulated with silicone resin. Moreover, chemical structure of the phosphors was characterized by XRD. Microstructure of the powders was observed by SEM. Spectra of excitation and emission for the phosphors were also obtained by a spectrophotometer. Effect of processing parameters on the luminescent properties of the powders was systematically studied to result in the phosphors with good chemical stability and maximal relative luminescent intensity.

  16. Quantum dots exhibit less bioaccumulation than free cadmium and selenium in the earthworm Eisenia andrei.

    Science.gov (United States)

    Stewart, David T R; Noguera-Oviedo, Katia; Lee, Vincent; Banerjee, Sarbajit; Watson, David F; Aga, Diana S

    2013-06-01

    The present study addresses the bioaccumulation behavior of cadmium selenide quantum dots by Eisenia andrei earthworms in a terrestrial environment. Earthworms were exposed to quantum dot-treated soil for up to 4 wk and analyzed for cadmium and selenium concentration using inductively coupled plasma mass spectrometry. Results were compared with those from earthworms exposed to cadmium nitrate and selenious acid, as positive controls, and those exposed in untreated soil (negative control). Earthworms exposed to quantum dots showed significant bioaccumulation of cadmium and selenium (5.3- and 1.5-fold higher concentration over negative controls, respectively) after 4 wk. Over the same 4 wk, positive control earthworms accumulated 9.2- and 2.2-fold higher cadmium and selenium, respectively, than negative controls for a much more substantial final body burden of the 2 elements. The concentrations also increased with exposure time; cadmium concentrations increased from 3600 ± 310 ng/g to 8080 ± 660 ng/g, from 1 to 4 wk, suggesting that further bioaccumulation may take place with even longer exposure time. The molar ratio of cadmium to selenium in the quantum dot-exposed worms (6.2) is closer to the ratios seen in positive control worms (7.2) than to the pure quantum dots (1.8), which implies that quantum dots are taken up predominantly in the degraded form. The results suggest that chemical modification of quantum dots to protect them from environmental degradation could potentially reduce bioaccumulation of the nanoparticles by earthworms. PMID:23417745

  17. Application of photocatalytic cadmium sulfide nanoparticles to detection of enzymatic activities of glucose oxidase and glutathione reductase using oxidation of 3,3′,5,5′-tetramethylbenzidine

    International Nuclear Information System (INIS)

    Highlights: • The light-powered nanosensor fabricated by enzymatic reactions was reported. • The sensor use energy of photons for oxidation of chromogenic enzymatic substrates. • Enzymatic assays for glucose oxidase and glutathione reductase were developed. - Abstract: It was found out that semiconductor CdS nanoparticles (NPs) are able to catalyze photooxidation of the well known chromogenic enzymatic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) by oxygen. The photocatalytical oxidation of TMB does not require hydrogen peroxide and its rate is directly proportional to the quantity of CdS NPs produced in situ through the interaction of Cd2+ and S2− ions in an aqueous medium. This phenomenon was applied to development of colorimetric sensitive assays for glucose oxidase and glutathione reductase based on enzymatic generation of CdS NPs acting as light-powered catalysts. Sensitivity of the developed chromogenic assays was of the same order of magnitude or even better than that of relevant fluorogenic assays. The present approach opens the possibility for the design of simple and sensitive colorimetric assays for a number of enzymes using inexpensive and available TMB as a universal chromogenic compound

  18. Application of photocatalytic cadmium sulfide nanoparticles to detection of enzymatic activities of glucose oxidase and glutathione reductase using oxidation of 3,3′,5,5′-tetramethylbenzidine

    Energy Technology Data Exchange (ETDEWEB)

    Grinyte, Ruta; Garai-Ibabe, Gaizka; Saa, Laura; Pavlov, Valeri, E-mail: vpavlov@cicbiomagune.es

    2015-06-30

    Highlights: • The light-powered nanosensor fabricated by enzymatic reactions was reported. • The sensor use energy of photons for oxidation of chromogenic enzymatic substrates. • Enzymatic assays for glucose oxidase and glutathione reductase were developed. - Abstract: It was found out that semiconductor CdS nanoparticles (NPs) are able to catalyze photooxidation of the well known chromogenic enzymatic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) by oxygen. The photocatalytical oxidation of TMB does not require hydrogen peroxide and its rate is directly proportional to the quantity of CdS NPs produced in situ through the interaction of Cd{sup 2+} and S{sup 2−} ions in an aqueous medium. This phenomenon was applied to development of colorimetric sensitive assays for glucose oxidase and glutathione reductase based on enzymatic generation of CdS NPs acting as light-powered catalysts. Sensitivity of the developed chromogenic assays was of the same order of magnitude or even better than that of relevant fluorogenic assays. The present approach opens the possibility for the design of simple and sensitive colorimetric assays for a number of enzymes using inexpensive and available TMB as a universal chromogenic compound.

  19. 石墨烯基纳米复合物修饰印刷电极伏安法测定水中镉%Differential Pulse Stripping Voltammetry Determination of Cadmium in Water Using Graphene Sheets- Au Composite Nano-particles Modified Screen-printed Carbon Electrodes

    Institute of Scientific and Technical Information of China (English)

    杨欣; 徐玲玲; 周秋兰; 林世新; 李龙飞

    2011-01-01

    构建了基于石墨烯(GS) -纳米金(Au)复合纳米微粒修饰印刷电极(SPCEs)的电化学传感器(SPCEs |GS/Au),建立了微分脉冲溶出伏安(DPSV)法测定水中痕量镉的电分析方法.采用扫描电镜(SEM)对电极表面进行了表征,DPSV法研究了镉的电化学性质.在优化实验条件下,溶出峰电流与Cd2+的质量浓度在2.5×10-7~2.5×10-5 g/L范围内呈良好线性,相关系数为0.998 0,检出限为1.8×10-7 g/L.将该方法用于实际水样的测定,回收率为96%~ 107%,实验结果与石墨炉原子吸收光谱(GF - AAS)法一致.该传感器采用复合纳米微粒修饰SPCEs,既能富集Cd2+又能扩增响应电流,且一次使用可抛弃、样品用量少、操作简便,可快速、准确地测定水样中的痕量镉.%An electrochemical sensor based on graphene sheets ( GS ) and gold nano-particles ( Au ) composite nano-particles modified screen-printed carbon electrodes (SPCEs) was fabricated (SPCEs | GS/Au) , and an electrochemical method was developed for the determination of trace cadmium ( Cd) in water by differential pulse stripping voltammetric ( DPSV) method. Au preparation and the construction processes of SPCEs | GS/Au electrode were characterized by scanning electron micrography (SEM) , and the electrochemical properties of Cd 2+ were investigated. Under the optimum conditions, a good linear relationship was obtained between peak current and Cd2 + concentration in the range of 2. 5 x 10-7 -2. 5 x 10-5 g/L(r2 =0. 998 0) with a detection limit(3σ) of 1. 8 x 10-7 g/L. The method was applied in the determination of Cd2 + concentration in real water samples with recoveries of 96% -107% . The analytical results were consistent with those of the graphite furnace atomic absorption spectrometric(GF - AAS) method. The SPCEs | GS/Au electrode showed a high response current and an enrichment ability due to the modification of composite nano-particles. Therefore, the electrode was suitable for the

  20. Multiple sulphur and lead sources recorded in hydrothermal exhalites associated with the Lemarchant volcanogenic massive sulphide deposit, central Newfoundland, Canada

    Science.gov (United States)

    Lode, Stefanie; Piercey, Stephen J.; Layne, Graham D.; Piercey, Glenn; Cloutier, Jonathan

    2016-04-01

    Metalliferous sedimentary rocks (mudstones, exhalites) associated with the Cambrian precious metal-bearing Lemarchant Zn-Pb-Cu-Au-Ag-Ba volcanogenic massive sulphide (VMS) deposit, Tally Pond volcanic belt, precipitated both before and after VMS mineralization. Sulphur and Pb isotopic studies of sulphides within the Lemarchant exhalites provide insight into the sources of S and Pb in the exhalites as a function of paragenesis and evolution of the deposit and subsequent post-depositional modification. In situ S isotope microanalyses of polymetallic sulphides (euhedral and framboidal pyrite, anhedral chalcopyrite, pyrrhotite, galena and euhedral arsenopyrite) by secondary ion mass spectrometry (SIMS) yielded δ34S values ranging from -38.8 to +14.4 ‰, with an average of ˜ -12.8 ‰. The δ34S systematics indicate sulphur was predominantly biogenically derived via microbial/biogenic sulphate reduction of seawater sulphate, microbial sulphide oxidation and microbial disproportionation of intermediate S compounds. These biogenic processes are coupled and occur within layers of microbial mats consisting of different bacterial/archaeal species, i.e., sulphate reducers, sulphide oxidizers and those that disproportionate sulphur compounds. Inorganic processes or sources (i.e., thermochemical sulphate reduction of seawater sulphate, leached or direct igneous sulphur) also contributed to the S budget in the hydrothermal exhalites and are more pronounced in exhalites that are immediately associated with massive sulphides. Galena Pb isotopic compositions by SIMS microanalysis suggest derivation of Pb from underlying crustal basement (felsic volcanic rocks of Sandy Brook Group), whereas less radiogenic Pb derived from juvenile sources leached from mafic volcanic rocks of the Sandy Brook Group and/or Tally Pond group. This requires that the hydrothermal fluids interacted with juvenile and evolved crust during hydrothermal circulation, which is consistent with the existing

  1. Chemical behaviors of different arsenic-bearing sulphides bio-oxidated by thermophilic bacteria

    Institute of Scientific and Technical Information of China (English)

    YANG Hong-ying; GONG En-pu; YANG Li-li; WANG Da-wen

    2005-01-01

    The study on arsenopyrite and realgar of bacterial oxidation shows that the chemical behaviors of different arsenic-bearing sulphides oxidated by thermophilic bacteria are quite distinct. Arsenopyrite is active and quickly eroded in bacteria-bearing solution. With a high leaching rate over 95%, the arsenopyrite phase cannot be detected by X-ray diffraction(XRD). Arsenopyrite is highly toxic to bacteria that at the initial stage of bio-oxidation, bacterial growth is inhibited and the number of bacterium cell drops from 2.26 × 108/mL to the lowest 2.01 × 105/mL. At the later stages of bio-oxidation, bacteria grow fast and reach 2.23 × 108/mL. Comparably, realgar is inertial and resistive to bacterial corrosion and oxidation. Arsenic in realgar crystal is hard to be leached and the residue is still realgar phase, as indicated by XRD. The cell number of bacteria varies a little, decreasing from 2.26 × 108/mL to 2.01 × 107/mL, during the bacterial oxidation. The results show that the crystal structure and arsenic valency of arsenic-bearing sulphides play a vital role during the leaching process of bacterial oxidation.

  2. Specific biofilter process design using bacteria capable of removing hydrogen sulphide from air emissions

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, R.N. [Alberta Environmental Centre, Vegreville, AB (Canada)

    1996-05-01

    The design and development of a biofilter unit which can remove hydrogen sulphide (H{sub 2}S) from air emissions, such as those found in the oil and gas industry and the Kraft wood pulping process, was discussed. Biofilters which contain species of bacteria which are able to oxidize H{sub 2}S have been very successful in removing high concentrations of H{sub 2}S from contaminated air streams. The biofilters could control noxious or offensive odours through aerobic metabolism of contaminants by microorganisms attached to such surfaces as peat or wood bark. Microbial oxidation of low molecular weight inorganic and volatile organic compounds were shown to result in their degradation to end products such as carbon dioxide, sulphate, water and new cell biomass. Research was directed toward the treatment of sulphur containing emissions generated during the sulphide recovery cycle in the Kraft wood pulping process, but since emissions are similar to those present in oil and gas industry, this technology was said to be equally applicable in the petroleum industry. 14 refs., 5 tabs., 8 figs.

  3. Flotation separation of arsenopyrite from several sulphide minerals with organic depressants

    Institute of Scientific and Technical Information of China (English)

    Wang Fuliang; Wang Ligang; Sun Chuanyao

    2008-01-01

    In this paper,the separation of arsenopyrite from chalcopyrite,pyrite,galena with organic depressants (guergum and sodium humic)was discussed,and the functioning mechanism of those organic depressants was dis-cussed.The experimental results of monomineral flotation indicated that both guergum and sodium humic have depress-ing effect on arsenopyrite in the presence of ethyl xanthate.Guergum and sodium humic showed different depressing a-bility to pyrite,chalcopyrite and galena,and the higher the pH value in pulp,the stronger the depressing ability.Ultra-violet-Visible Spectrophotometric study showed that the adsorption layer of xanthate on surface of minerals had been de-sorbed by the two organic depressants,and the selective desorption of the collector layer was found from different miner-als.The xanthate cover on minerals surface was set free when dosage of the organic depressants was high enough.For artificially-mixed minerals,the separation of arsenopyrite from other sulphides was successfully realized by controlling dosage of the organic depressants.And sodium humic had been used successfully to decrease arsenic content in sulphide concentr ates in a commercial Lead-Zinc concentrator.

  4. Magnetic mineralogy of the Hongqiling Cu-Ni sulphide deposit:Implications for ore genesis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Pyrrhotite is one of the common ore minerals in Cu-Ni sulphide deposits, but only monoclinic pyrrhotite is ferromagnetic at room temperature. X-ray and EPA analyses reveal that most pyrrhotite forming sideronitic texture in the Hongqiling Cu-Ni sulphide deposit is monoclinic, but that in the massive ore is a mixture of monoclinic and hexagonal pyrrhotites. Differential thermal and magneticthermogravimetric analyses of massive ore indicate a magnetic transition and heat absorption at 323℃, suggesting that this temperature is the thermomagnetic and phase transition point of pyrrhotite. For massive pyrrhotite ores heated at 400℃ for 30 h and then quenched by cool water, the monoclinic pyrrhotite (mpo) transforms completely into the hexagonal pyrrhotite (hpo). However, all the pyrrhotites resulting from slow cooling of the sample in air are mpo. These results indicate that transformation between hpo and mpo depends upon the cooling rate. Therefore, massive ores in this deposit might have been formed via rapid cooling of ore melts. On the other hand, it is significant to study the effect of the ratio of the magnetite in total ores on the genesis of magmatic Cu-Ni suphide deposits.

  5. Hydrogen sulphide release to surface waters at the Precambrian/Cambrian boundary.

    Science.gov (United States)

    Wille, Martin; Nägler, Thomas F; Lehmann, Bernd; Schröder, Stefan; Kramers, Jan D

    2008-06-01

    Animal-like multicellular fossils appeared towards the end of the Precambrian, followed by a rapid increase in the abundance and diversity of fossils during the Early Cambrian period, an event also known as the 'Cambrian explosion'. Changes in the environmental conditions at the Precambrian/Cambrian transition (about 542 Myr ago) have been suggested as a possible explanation for this event, but are still a matter of debate. Here we report molybdenum isotope signatures of black shales from two stratigraphically correlated sample sets with a depositional age of around 542 Myr. We find a transient molybdenum isotope signal immediately after the Precambrian/Cambrian transition. Using a box model of the oceanic molybdenum cycle, we find that intense upwelling of hydrogen sulphide-rich deep ocean water best explains the observed Early Cambrian molybdenum isotope signal. Our findings suggest that the Early Cambrian animal radiation may have been triggered by a major change in ocean circulation, terminating a long period during which the Proterozoic ocean was stratified, with sulphidic deep water.

  6. Half-cell potentials of semiconductive simple binary sulphides in aqueous solution

    Science.gov (United States)

    Sato, M.

    1966-01-01

    Theoretical consideration of the charge-transfer mechanism operative in cells with an electrode of a semiconductive binary compound leads to the conclusion that the half-cell potential of such a compound is not only a function of ionic activities in the electrolytic solution, but also a function of the activities of the component elements in the compound phase. The most general form of the electrode equation derived for such a compound with a formula MiXj which dissociates into Mj+ and Xi- ions in aqueous solution is. EMiXj = EMiXj0 + R T 2 ij ln [ (sua Mj+)aqi ?? (suaX)jMiXj/ (suaXi-)aqj ?? (suaM)iMiXj],. where. EMiXj0 = 1 2(EM,Mj+0 + EXi-,X). The equation can be modified to other forms. When applied to semiconductive simple binary sulphides, these equations appear to give better descriptions of the observed electrode potentials of such sulphides than any other proposed equations. ?? 1966.

  7. Endosymbiotic sulphate-reducing and sulphide-oxidizing bacteria in an oligochaete worm.

    Science.gov (United States)

    Dubilier, N; Mülders, C; Ferdelman, T; de Beer, D; Pernthaler, A; Klein, M; Wagner, M; Erséus, C; Thiermann, F; Krieger, J; Giere, O; Amann, R

    2001-05-17

    Stable associations of more than one species of symbiont within a single host cell or tissue are assumed to be rare in metazoans because competition for space and resources between symbionts can be detrimental to the host. In animals with multiple endosymbionts, such as mussels from deep-sea hydrothermal vents and reef-building corals, the costs of competition between the symbionts are outweighed by the ecological and physiological flexibility gained by the hosts. A further option for the coexistence of multiple symbionts within a host is if these benefit directly from one another, but such symbioses have not been previously described. Here we show that in the gutless marine oligochaete Olavius algarvensis, endosymbiotic sulphate-reducing bacteria produce sulphide that can serve as an energy source for sulphide-oxidizing symbionts of the host. Thus, these symbionts do not compete for resources but rather share a mutalistic relationship with each other in an endosymbiotic sulphur cycle, in addition to their symbiotic relationship with the oligochaete host.

  8. Oxic microshield and local pH enhancement protects Zostera muelleri from sediment derived hydrogen sulphide.

    Science.gov (United States)

    Brodersen, Kasper Elgetti; Nielsen, Daniel Aagren; Ralph, Peter J; Kühl, Michael

    2015-02-01

    Seagrass is constantly challenged with transporting sufficient O₂ from above- to belowground tissue via aerenchyma in order to maintain aerobic metabolism and provide protection against phytotoxins. Electrochemical microsensors were used in combination with a custom-made experimental chamber to analyse the belowground biogeochemical microenvironment of Zostera muelleri under changing environmental conditions. Measurements revealed high radial O₂ release of up to 500 nmol O2 cm(-2) h(-1) from the base of the leaf sheath, maintaining a c. 300-μm-wide plant-mediated oxic microzone and thus protecting the vital meristematic regions of the rhizome from reduced phytotoxic metabolites such as hydrogen sulphide (H₂S). H₂S intrusion was prevented through passive diffusion of O₂ to belowground tissue from leaf photosynthesis in light, as well as from the surrounding water column into the flow-exposed plant parts during darkness. Under water column hypoxia, high belowground H₂S concentrations at the tissue surface correlated with the inability to sustain the protecting oxic microshield around the meristematic regions of the rhizome. We also found increased pH levels in the immediate rhizosphere of Z. muelleri, which may contribute to further detoxification of H₂S through shifts in the chemical speciation of sulphide. Zostera muelleri can modify the geochemical conditions in its immediate rhizosphere, thereby reducing its exposure to H₂S. PMID:25367685

  9. Influence of methanethiol on biological sulphide oxidation in gas treatment system.

    Science.gov (United States)

    Roman, Pawel; Bijmans, Martijn F M; Janssen, Albert J H

    2016-01-01

    Inorganic and organic sulphur compounds such as hydrogen sulphide (H2S) and thiols (RSH) are unwanted components in sour gas streams (e.g. biogas and refinery gases) because of their toxicity, corrosivity and bad smell. Biological treatment processes are often used to remove H2S at small and medium scales (principles have been further studied by assessing the effect of methanethiol on the biological conversion of H2S under a wide range of redox conditions covering not only sulphur but also sulphate-producing conditions. Furthermore, our experiments were performed in an integrated system consisting of a gas absorber and a bioreactor in order to assess the effect of methanethiol on the overall gas treatment efficiency. This study shows that methanethiol inhibits the biological oxidation of H2S to sulphate by way of direct suppression of the cytochrome c oxidase activity in biomass, whereas the oxidation of H2S to sulphur was hardly affected. We estimated the kinetic parameters of biological H2S oxidation that can be used to develop a mathematical model to quantitatively describe the biodesulphurization process. Finally, it was found that methanethiol acts as a competitive inhibitor; therefore, its negative effect can be minimized by increasing the enzyme (biomass) concentration and the substrate (sulphide) concentration, which in practice means operating the biodesulphurization systems under low redox conditions. PMID:26652658

  10. Hydrogen sulphide release to surface waters at the Precambrian/Cambrian boundary.

    Science.gov (United States)

    Wille, Martin; Nägler, Thomas F; Lehmann, Bernd; Schröder, Stefan; Kramers, Jan D

    2008-06-01

    Animal-like multicellular fossils appeared towards the end of the Precambrian, followed by a rapid increase in the abundance and diversity of fossils during the Early Cambrian period, an event also known as the 'Cambrian explosion'. Changes in the environmental conditions at the Precambrian/Cambrian transition (about 542 Myr ago) have been suggested as a possible explanation for this event, but are still a matter of debate. Here we report molybdenum isotope signatures of black shales from two stratigraphically correlated sample sets with a depositional age of around 542 Myr. We find a transient molybdenum isotope signal immediately after the Precambrian/Cambrian transition. Using a box model of the oceanic molybdenum cycle, we find that intense upwelling of hydrogen sulphide-rich deep ocean water best explains the observed Early Cambrian molybdenum isotope signal. Our findings suggest that the Early Cambrian animal radiation may have been triggered by a major change in ocean circulation, terminating a long period during which the Proterozoic ocean was stratified, with sulphidic deep water. PMID:18509331

  11. Interferometric investigation and simulation of refractive index in glass matrixes containing nanoparticles of varying sizes

    Energy Technology Data Exchange (ETDEWEB)

    Feeney, Michael Gerard; Ince, Rabia; Yukselici, Mehmet Hikmet; Allahverdi, Cagdas

    2011-07-01

    The relationship between refractive index and nanoparticle radii of cadmium selenide (CdSe) nanoparticles embedded within glass matrixes was investigated experimentally and by simulations. A homemade automated Michelson interferometer arrangement employing a rotating table and a He-Ne laser source at a wavelength of 632.8 nm determined the refractive index versus nanoparticle radii of embedded cadmium selenide (CdSe) nanoparticles. The refractive index was found to decrease linearly with nanoparticle radius increase. However, one sample showed a step increase in refractive index; on spectroscopic analysis, it was found that its resonant wavelength matched that of the He-Ne source wavelength. The simulations showed that two conditions caused the step increase in refractive index: low plasma frequency and matched sample and source resonances. This simple interferometer setup defines a new method of determining the radii of nanoparticles embedded in substrates and enables refractive index tailoring by modification of exact annealing conditions.

  12. 碳纳米颗粒修饰丝网印刷电极测定百合镉含量%Detection of cadmium content of lily by carbon nanoparticles modified screen-printed electrode

    Institute of Scientific and Technical Information of China (English)

    郑琦琦; 俞永华; 吴坚

    2015-01-01

    People are more and more interested in health foods with the improvement of living standard. Edible lily tastes sweet with a little bitter and can be used to treat cough, phthisis, beriberi, and so on. There are almost 10 species of edible lily in China. The production of lily is in rapid expansion. However, the sample of lily is usually found to have cadmium (Cd) above the national standard. Cd is one of the toxic heavy metals. It will cause damage of lung and kidney. There are a lot of methods to detect the cd in foods, such as graphite furnace atomic absorption spectrometry, atomic fluorescence spectrometry, and spectrophotometry. Although these methods have high precision, they need large-scale equipment, high cost, and professional staff, and even some use toxic reagents. Scientists developed several rapid determination methods, one of which was electrochemical detection. In this paper, we designed a novel electrode, which combined screen printing technique with carbon nanodots to detect cd in lily. Carbon nanodots were prepared with candle soot which was low-cost and easily obtained. The carbon nanodots of 1.5μL dissolving in dimethyl formamide were added twice onto the working electrode of screen-printed electrode which was fabricated in our laboratory. Using scanning electron microscope to compare the surface texture of modified screen-printed electrode with original one, we found that the former had more uniform particles. We also compared the electrochemical performance by cyclic voltammetry. The result showed that the modified screen-printed electrode had larger peak current and smaller peak separation which meant superior electrochemical performance. Furthermore, we tested an HAc-NaAc buffer solution with 75μg/L Cd2+ using 2 different electrodes noted above by square-wave anodic stripping voltammetry. The peak potential of original screen-printed electrode was?0.65 V, while modified one was?0.64 V. The anodic stripping voltammogarm showed that the

  13. Latex-mediated synthesis of ZnS nanoparticles: green synthesis approach

    Energy Technology Data Exchange (ETDEWEB)

    Hudlikar, Manish; Joglekar, Shreeram [University of Pune, Division of Biochemistry, Department of Chemistry (India); Dhaygude, Mayur [National Chemical Laboratory, Polymer Science and Engineering Division (India); Kodam, Kisan, E-mail: kodam@chem.unipune.ac.in [University of Pune, Division of Biochemistry, Department of Chemistry (India)

    2012-05-15

    A low-cost, green synthesis of ZnS nanoparticles is reported using 0.3 % latex solution prepared from Jatropha curcas L. ZnS nanoparticles were characterized by X-ray diffraction, selected area electron diffraction, transmission electron microscopy, energy dispersive analysis of X-rays, UV-vis optical absorption and photoluminescence techniques. Fourier Transform Infrared Spectroscopy was performed to find the role of cyclic peptides namely curcacycline A (an octapeptide), curcacycline B (a nonapeptide) and curcain (an enzyme) as a possible reducing and stabilizing agents present in the latex of J. curcas L. The average size of ZnS nanoparticles was found to be 10 nm. Latex of J. curcas L. itself acts as a source of sulphide (S{sup -2}) ions that are donated to Zn ions under present experimental conditions. Source of sulphide (S{sup -2}) ions is still unclear, but we speculate that cysteine or thiol residues present in enzyme curcain may be donating these sulphide (S{sup -2}) ions.

  14. Cadmium detoxification processes in the digestive gland of cephalopods in relation to accumulated cadmium concentrations

    OpenAIRE

    Bustamante, Paco; Cosson, Richard; Gallien, Isabelle; Caurant, Florence; Miramand, Pierre

    2002-01-01

    International audience The high concentrations of cadmium recorded in the digestive gland of cephalopods from various temperate and subpolar waters suggest that these molluscs have developed efficient cadmium detoxification mechanisms. The subcellular distribution of cadmium in the digestive gland cells was investigated in seven cephalopod species from the Bay of Biscay (France) and the Faroe Islands. In most species, cadmium was mainly found in the cytosolic fraction of the digestive glan...

  15. Cadmium content of plants as affected by soil cadmium concentration

    Energy Technology Data Exchange (ETDEWEB)

    Lehoczky, E. [Pannon Univ. of Agricultural Sciences, Keszthely (Hungary); Szabados, I.; Marth, P. [Plant Health and Soil Conservation Station, Higany (Hungary)

    1996-12-31

    Pot experiments were conducted in greenhouse conditions to study the effects of increasing cadmium (Cd) levels on biomass production and Cd contents in corn, (Zea mays L.), garlic (Allium sativum L.), and spinach (Spinacia oleracea L.). Plants were grown in two soil types: Eutric cambisol soil and A gleyic luvisol soil. Spinach proved to be the most sensitive to Cd treatments as its biomass considerably decreased with the increasing Cd levels. Cadmium contents of the three crops increased with increasing levels of Cd applications. Statistical differences were observed in the Cd contents of crops depending on soil type. With the same Cd rates, Cd tissue concentration of test plants grown in the strongly acidic Gleyic luvisol soil were many times higher than that of plants grown in a neutral Eutric cambisol soil. 14 refs., 4 tabs.

  16. Cadmium Exposure and Pancreatic Cancer in South Louisiana

    OpenAIRE

    Luckett, Brian G.; L. Joseph Su; Rood, Jennifer C.; Elizabeth T. H. Fontham

    2012-01-01

    Cadmium has been hypothesized to be a pancreatic carcinogen. We test the hypothesis that cadmium exposure is a risk factor for pancreatic cancer with a population-based case-control study sampled from a population with persistently high rates of pancreatic cancer (south Louisiana). We tested potential dietary and nondietary sources of cadmium for their association with urinary cadmium concentrations which reflect long-term exposure to cadmium due to the accumulation of cadmium in the kidney c...

  17. Laser-assisted synthesis, and structural and thermal properties of ZnS nanoparticles stabilised in polyvinylpyrrolidone

    Energy Technology Data Exchange (ETDEWEB)

    Onwudiwe, Damian C. [Chemical Resource Beneficiation (CRB) Research Focus Area, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Krüger, Tjaart P.J. [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa); Jordaan, Anine [Laboratory for Electron Microscopy, CRB Research Focus Area, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Strydom, Christien A., E-mail: christien.strydom@nwu.ac.za [Chemical Resource Beneficiation (CRB) Research Focus Area, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa)

    2014-12-01

    Graphical abstract: - Highlights: • Zinc sulphide (ZnS) nanoparticles were synthesised by laser irradiation. • The structural and morphological properties of the prepared samples were analysed. • Larger particles were obtained by using Na{sub 2}S instead of TAA as the sulphur source. • Phonon softening and line broadening of the peaks were observed. • Size reduction occurred in the samples obtained from both sources. - Abstract: Zinc sulphide (ZnS) nanoparticles have been synthesised by a green approach involving laser irradiation of an aqueous solution of zinc acetate (Znac{sub 2}) and sodium sulphide (Na{sub 2}S·9H{sub 2}O) or thioacetamide (TAA) in polyvinylpyrrolidone (PVP). The structural and morphological properties of the prepared samples were analysed using a transmission electron microscope, TEM, a high resolution transmission electron microscope, HRTEM, X-ray diffraction, and Raman spectroscopy. The thermal properties were studied using a simultaneous thermal analyser (SDTA). Better dispersed and larger particles were obtained by using sodium sulphide (Na{sub 2}S) instead of TAA as the sulphur source. X-ray diffraction (XRD) analyses and Raman measurement show that the particles have a cubic structure, which is usually a low temperature phase of ZnS. There were phonon softening and line broadening of the peaks which are attributed to the phonon confinement effect. The average crystallite size of the ZnS nanoparticles estimated from the XRD showed a reduction in size from 13.62 to 10.42 nm for samples obtained from Na{sub 2}S, and 9.13 to 8.16 nm for samples obtained from TAA, with an increase in the time of irradiation. The thermal stability of PVP was increased due to the incorporation of the ZnS nanoparticles in the matrices. The absorption spectra showed that the nanoparticles exhibit quantum confinement effects.

  18. Zone refining of cadmium and related characterization

    Indian Academy of Sciences (India)

    N R Munirathnam; D S Prasad; Ch Sudheer; J V Rao; T L Prakash

    2005-06-01

    We present the zone refining results of cadmium using horizontal resistive zone refiner under constant flow of moisture free hydrogen gas. The boron impurity in cadmium can be avoided using quartz (GE 214 grade) boat in lieu of high pure graphite boat. The analytical results using inductively coupled plasma optical emission spectrometry (ICPOES) show that majority of the impurities are less than the detection limits. Comparatively, zinc is the most difficult impurity element to remove in cadmium matrix by zone refining.

  19. Electrodialytic Removal of Cadmium from Straw Ash

    DEFF Research Database (Denmark)

    Hansen, Henrik; Ottosen, Lisbeth M.; Villumsen, Arne;

    1999-01-01

    A problem with flyash from straw and wood combustion is the high level of heavy metals, especially cadmium. Two electrodialytic remediation experiments were carried out on cadmium polluted flyash from straw combustion. The flyash could be cleaned to 1/3 of its initial level after 24 days...... of remediation. Further removal of cadmium could be possible with longer remediation time or a higher current density...

  20. Fundamental Studies on the Electrochemical Behaviour of Carbon Steel Exposed in Sulphide and Sulphate-Reducing Environments

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    The aim of the report is to give a fundamental understanding of the response of different electrochemical techniques on carbon steel in a sulphide environment as well as in a biologically active sulphate-reducing environment (SRB). This will form the basis for further studies and for recommendati...

  1. Geochemical, metagenomic and metaproteomic insights into trace metal utilization by methane-oxidizing microbial consortia in sulphidic marine sediments.

    Science.gov (United States)

    Glass, Jennifer B; Yu, Hang; Steele, Joshua A; Dawson, Katherine S; Sun, Shulei; Chourey, Karuna; Pan, Chongle; Hettich, Robert L; Orphan, Victoria J

    2014-06-01

    Microbes have obligate requirements for trace metals in metalloenzymes that catalyse important biogeochemical reactions. In anoxic methane- and sulphide-rich environments, microbes may have unique adaptations for metal acquisition and utilization because of decreased bioavailability as a result of metal sulphide precipitation. However, micronutrient cycling is largely unexplored in cold (≤ 10°C) and sulphidic (> 1 mM ΣH(2)S) deep-sea methane seep ecosystems. We investigated trace metal geochemistry and microbial metal utilization in methane seeps offshore Oregon and California, USA, and report dissolved concentrations of nickel (0.5-270 nM), cobalt (0.5-6 nM), molybdenum (10-5600 nM) and tungsten (0.3-8 nM) in Hydrate Ridge sediment porewaters. Despite low levels of cobalt and tungsten, metagenomic and metaproteomic data suggest that microbial consortia catalysing anaerobic oxidation of methane (AOM) utilize both scarce micronutrients in addition to nickel and molybdenum. Genetic machinery for cobalt-containing vitamin B12 biosynthesis was present in both anaerobic methanotrophic archaea (ANME) and sulphate-reducing bacteria. Proteins affiliated with the tungsten-containing form of formylmethanofuran dehydrogenase were expressed in ANME from two seep ecosystems, the first evidence for expression of a tungstoenzyme in psychrophilic microorganisms. Overall, our data suggest that AOM consortia use specialized biochemical strategies to overcome the challenges of metal availability in sulphidic environments.

  2. Stimulated emission of surface plasmon polaritons by lead-sulphide quantum dots at near infra-red wavelengths

    DEFF Research Database (Denmark)

    Radko, Ilya P.; Nielsen, Michael Grøndahl; Albrektsen, Ole;

    2010-01-01

    Amplification of surface plasmon polaritons (SPPs) in planar metal-dielectric structure through stimulated emission is investigated using leakage-radiation microscopy configuration. The gain medium is a thin polymethylmethacrylate layer doped with lead-sulphide nanocrystals emitting at near...

  3. Magnetic iron-nickel sulphides in the Pliocene and Pleistocene marine marls from the Vrica section (Calabria, Italy)

    NARCIS (Netherlands)

    Velzen, A.J. van; Dekkers, M.J.; Zijderveld, J.D.A.

    1993-01-01

    The rock magnetic properties of the late Pliocene and early Pleistocene open-marine marls from the Vrica section in Calabria (Italy) point to magnetic sulphide as the main magnetic mineral and remanence carrier. The maximum blocking temperatures, however, are between 340 and 360°C, which is too high

  4. Performance evaluation of oxygen, air and nitrate for the microaerobic removal of hydrogen sulphide in biogas from sludge digestion.

    Science.gov (United States)

    Díaz, I; Lopes, A C; Pérez, S I; Fdz-Polanco, M

    2010-10-01

    The removal performance of hydrogen sulphide in severely polluted biogas produced during the anaerobic digestion of sludge was studied by employing pure oxygen, air and nitrate as oxidant reactives supplied to the biodigester. Research was performed in a 200-L digester with an hydraulic retention time (HRT) of ∼20 days under mesophilic conditions. The oxygen supply (0.25 N m³/m³ feed) to the bioreactor successfully reduced the hydrogen sulphide content from 15,811 mg/N m³ to less than 400 mg/N m³. The introduction of air (1.27 N m³/m³ feed) removed more than 99% of the hydrogen sulphide content, with a final concentration of ∼55 mg/N m³. COD removal, VS reduction and methane yield were not affected under microaerobic conditions; however, methane concentration in the biogas decreased when air was employed as a result of nitrogen dilution. The nitrate addition was not effective for hydrogen sulphide removal in the biogas.

  5. Bioavailability of cadmium from linseed and cocoa

    OpenAIRE

    Hansen, Max; Rasmussen, Rie Romme; Sloth, Jens Jørgen

    2014-01-01

    The exposure of the European population to cadmium from food is high compared with the tolerable weekly intake of 2.5 μg/kg bodyweight set by EFSA in 2009. Only few studies on the bioavailability of cadmium from different food sources has been performed but this information in very important for the food authorities in order to give correct advises to the population. The aim of this study was to investigate the bioavailability of cadmium from whole linseed, crushed linseed, cocoa and cadmium ...

  6. The Epigenetic Effects of Prenatal Cadmium Exposure.

    Science.gov (United States)

    Vilahur, Nadia; Vahter, Marie; Broberg, Karin

    2015-06-01

    Prenatal exposure to the highly toxic and common pollutant cadmium has been associated with adverse effects on child health and development. However, the underlying biological mechanisms of cadmium toxicity remain partially unsolved. Epigenetic disruption due to early cadmium exposure has gained attention as a plausible mode of action, since epigenetic signatures respond to environmental stimuli and the fetus undergoes drastic epigenomic rearrangements during embryogenesis. In the current review, we provide a critical examination of the literature addressing prenatal cadmium exposure and epigenetic effects in human, animal, and in vitro studies. We conducted a PubMed search and obtained eight recent studies addressing this topic, focusing almost exclusively on DNA methylation. These studies provide evidence that cadmium alters epigenetic signatures in the DNA of the placenta and of the newborns, and some studies indicated marked sexual differences for cadmium-related DNA methylation changes. Associations between early cadmium exposure and DNA methylation might reflect interference with de novo DNA methyltransferases. More studies, especially those including environmentally relevant doses, are needed to confirm the toxicoepigenomic effects of prenatal cadmium exposure and how that relates to the observed health effects of cadmium in childhood and later life.

  7. Upconversion Nanoparticles for Bioimaging and Regenerative Medicine

    OpenAIRE

    González-Béjar, María; Francés-Soriano, Laura; Pérez-Prieto, Julia

    2016-01-01

    Nanomaterials are proving useful for regenerative medicine in combination with stem cell therapy. Nanoparticles (NPs) can be administrated and targeted to desired tissues or organs and subsequently be used in non-invasive real-time visualization and tracking of cells by means of different imaging techniques, can act as therapeutic agent nanocarriers, and can also serve as scaffolds to guide the growth of new tissue. NPs can be of different chemical nature, such as gold, iron oxide, cadmium se...

  8. Unique evolutionary trajectories in repeated adaptation to hydrogen sulphide-toxic habitats of a neotropical fish (Poecilia mexicana).

    Science.gov (United States)

    Pfenninger, Markus; Patel, Simit; Arias-Rodriguez, Lenin; Feldmeyer, Barbara; Riesch, Rüdiger; Plath, Martin

    2015-11-01

    Replicated ecological gradients are prime systems to study processes of molecular evolution underlying ecological divergence. Here, we investigated the repeated adaptation of the neotropical fish Poecilia mexicana to habitats containing toxic hydrogen sulphide (H2 S) and compared two population pairs of sulphide-adapted and ancestral fish by sequencing population pools of >200 individuals (Pool-Seq). We inferred the evolutionary processes shaping divergence and tested the hypothesis of increase of parallelism from SNPs to molecular pathways. Coalescence analyses showed that the divergence occurred in the face of substantial bidirectional gene flow. Population divergence involved many short, widely dispersed regions across the genome. Analyses of allele frequency spectra suggest that differentiation at most loci was driven by divergent selection, followed by a selection-mediated reduction of gene flow. Reconstructing allelic state changes suggested that selection acted mainly upon de novo mutations in the sulphide-adapted populations. Using a corrected Jaccard index to quantify parallel evolution, we found a negligible proportion of statistically significant parallel evolution of Jcorr  = 0.0032 at the level of SNPs, divergent genome regions (Jcorr  = 0.0061) and genes therein (Jcorr  = 0.0091). At the level of metabolic pathways, the overlap was Jcorr  = 0.2545, indicating increasing parallelism with increasing level of biological integration. The majority of pathways contained positively selected genes in both sulphide populations. Hence, adaptation to sulphidic habitats necessitated adjustments throughout the genome. The largely unique evolutionary trajectories may be explained by a high proportion of de novo mutations driving the divergence. Our findings favour Gould's view that evolution is often the unrepeatable result of stochastic events with highly contingent effects.

  9. Effects of Annealing on Structural Properties of Copper Zinc Tin Sulphide (CZTS Material

    Directory of Open Access Journals (Sweden)

    K.K. Patel

    2013-05-01

    Full Text Available Copper Zinc Tin Sulphide compound was synthesized from its elemetal precursurs using simple solid state method. Being quarternary material, there is a large probability of formation of secondary phases like SnS, ZnS, CuS during the material growth process and it requires a detail investigation on the effects of synthesis parameters on the composition and structural properties of the CZTS compound. Here we report the study of effects of annealing on the synthesized compound. The annealing was performed at two different temperatures in the presence of Sulphur. The structural and compositional properties of the as-grown and annealed samples were examined by X-ray diffraction (XRD and Energy Dispersive Analysis of X-Ray (EDAX. The formation of Kesterite CZTS phase was confirmed by Raman Spectroscopy.

  10. Relationship between solids flux and froth features in batch flotation of sulphide ore

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-sheng; Aldrich Chris

    2005-01-01

    The froth features in the batch flotation of a sulphide ore were investigated by using the digital image parameters of the froth, the small number emphasis(Nsne), the average grey level(Dagl) and the instability number(Nins), under different conditions of impeller speeds and aeration rates. It is found that the value of Nsne is strongly dependent on the average bubble size of the froth and Dagl on the volume fraction of solid in the froth, and the froth features during the batch flotation are influenced by impeller speed and aeration rate. A kinetic model of the concentrate solid flux was developed which relates the flotation process to the image parameters, Nsne and Dagl of the froth and predictions are well consistent with the experimental data.

  11. A novel process for sorting fine-sized sulphide minerals by biocoagulation

    Institute of Scientific and Technical Information of China (English)

    H.Z.KUYUMCU; J.PINKA; T.BIELIG

    2008-01-01

    Based on a process design idea,investigations at Technical University of Berlin confirm that the biocoagulation of microorganisms and solid particles would be a new method to generate coarser particles suitable for sorting.The procedure of selective biocoagulation of microorganisms,e.g.yeasts like Saccharomyces cerevisiae and Yarrowia lipolytica respectively,and micro-dispersed solids,e.g.minerals like galena and sphalerite,has been analyzed as a basis for a novel sorting process.Therefore,especially the characteristics of the cell surface of the microorganisms,e.g.the electrostatic charge and the composition of extracellular polymeric substances,as well as their influence on the selective biocoagulation were studied.Experimental investigations show that the microorganisms and the sulphide particles below 10 μm coagulate effectively.Furthermore,the flotation is suitable for the separation of the selectively formed biocoagulates.With the designed column flotation,satisfying recovery rates are reached.

  12. Contents and sulphur isotope composition of trace sulphate and sulphide in various rock types

    International Nuclear Information System (INIS)

    The in vacuo Kiba extraction technique for trace sulphate and sulphide has been extended to a variety of rocks including some altered granites provided by the Canadian Nuclear Fuel Waste Management Programme. Although the technique requires considerable development, it shows promise for determining the redox conditions, temperature, and the sulphur isotope composition of dissolved species in fluids involved in initial mineralization and subsequent alteration processes. This may in turn be used to identify sources of sulphur in fluids and provide information about long term weathering of resistant rocks. Preliminary concentration and sulphur isotope data for altered granite samples from the Underground Research Laboratory, Whiteshell, Manitoba suggest that sulphur of other than igneous origin is minor or absent. (author)

  13. Structural, optical and electrochromic properties of nickel oxide thin films grown from electrodeposited nickel sulphide

    International Nuclear Information System (INIS)

    Nickel oxide thin films were grown onto FTO-coated glass substrates by a two-step process: electrodeposition of nickel sulphide and their thermal oxidation at 425, 475 and 525 deg. C. The influence of thermal oxidation temperature on structural, optical, morphological and electrochromic properties was studied. The structural properties undoubtedly revealed NiO formation. The electrochromic properties were studied by means of cyclic voltammetry. The films exhibited anodic electrochromism, changing from a transparent state to a coloured state at +0.75 V versus SCE, i.e. by simultaneous ion and electron ejection. The transmittance in the coloured and bleached states was recorded to access electrochromic quality of the films. Colouration efficiency and electrochromic reversibility were found to be maximum (21 mC/cm2 and 89%, respectively) for the films oxidized at 425 deg. C. The optical band gap energy of nickel oxide slightly varies with increase in annealing temperature

  14. Structural, optical and electrochromic properties of nickel oxide thin films grown from electrodeposited nickel sulphide

    Energy Technology Data Exchange (ETDEWEB)

    Uplane, M.M.; Mujawar, S.H.; Inamdar, A.I.; Shinde, P.S.; Sonavane, A.C. [Thin Film Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, Maharashtra (India); Patil, P.S. [Thin Film Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, Maharashtra (India)], E-mail: psp_phy@unishivaji.ac.in

    2007-10-15

    Nickel oxide thin films were grown onto FTO-coated glass substrates by a two-step process: electrodeposition of nickel sulphide and their thermal oxidation at 425, 475 and 525 deg. C. The influence of thermal oxidation temperature on structural, optical, morphological and electrochromic properties was studied. The structural properties undoubtedly revealed NiO formation. The electrochromic properties were studied by means of cyclic voltammetry. The films exhibited anodic electrochromism, changing from a transparent state to a coloured state at +0.75 V versus SCE, i.e. by simultaneous ion and electron ejection. The transmittance in the coloured and bleached states was recorded to access electrochromic quality of the films. Colouration efficiency and electrochromic reversibility were found to be maximum (21 mC/cm{sup 2} and 89%, respectively) for the films oxidized at 425 deg. C. The optical band gap energy of nickel oxide slightly varies with increase in annealing temperature.

  15. Structural, optical and electrochromic properties of nickel oxide thin films grown from electrodeposited nickel sulphide

    Science.gov (United States)

    Uplane, M. M.; Mujawar, S. H.; Inamdar, A. I.; Shinde, P. S.; Sonavane, A. C.; Patil, P. S.

    2007-10-01

    Nickel oxide thin films were grown onto FTO-coated glass substrates by a two-step process: electrodeposition of nickel sulphide and their thermal oxidation at 425, 475 and 525 °C. The influence of thermal oxidation temperature on structural, optical, morphological and electrochromic properties was studied. The structural properties undoubtedly revealed NiO formation. The electrochromic properties were studied by means of cyclic voltammetry. The films exhibited anodic electrochromism, changing from a transparent state to a coloured state at +0.75 V versus SCE, i.e. by simultaneous ion and electron ejection. The transmittance in the coloured and bleached states was recorded to access electrochromic quality of the films. Colouration efficiency and electrochromic reversibility were found to be maximum (21 mC/cm 2 and 89%, respectively) for the films oxidized at 425 °C. The optical band gap energy of nickel oxide slightly varies with increase in annealing temperature.

  16. Resonant soft X-ray reflectivity as a sensitive probe to investigate polished zinc sulphide surface

    International Nuclear Information System (INIS)

    Resonant soft X-ray reflectivity measurements at and near the L3 absorption edge of sulphur have been performed on mechanically polished zinc sulphide using Indus-1 synchrotron source. A sulphur rich surface (∼15 nm thick) consisting of two layers with gradient electron density distribution was uniquely determined. As compared to bulk ZnS, the top layer has ∼30-50% less electron density whereas, the intermediate layer has ∼10-18% less electron density. Conventional hard X-ray reflectivity measurement at Cu Kα wavelength also indicates low electron density (sulphur rich) surface of ZnS but the technique was found insensitive for unique determination of electron density distribution. Optical constants of ZnS in the soft X-ray region (100-250 eV) have been reported for the first time and were in good agreement with the theoretically reported values.

  17. Probabilistic consequence assessment of hydrogen sulphide releases from a heavy water plant

    International Nuclear Information System (INIS)

    This report provides a summary of work carried out on behalf of the Atomic Energy Control Board, concerned with the consequences of accidental releases to the atmosphere of hydrogen sulphide (H2S) at a heavy water plant. In this study, assessments of consequences are made in terms of the probabilities of a range of possible outcomes, i.e., numbers of fatalities, given a certain release scenario. The report describes the major features of a computer model which was developed to calculate the consequences and their associated probabilities, and the major input data used in applying the model to a consequence assessment of the Bruce heavy water plant (HWP) in Ontario. The results of the sensitivity analyses of the model are summarized. Finally, the results of the consequence assessments of 43 accidental release scenarios at the Bruce HWP are summarized, together with a number of conclusions which were drawn from these results regarding the predicted consequences and the factors which influence them

  18. Bacterial consortium for copper extraction from sulphide ore consisting mainly of chalcopyrite

    Science.gov (United States)

    Romo, E.; Weinacker, D.F.; Zepeda, A.B.; Figueroa, C.A.; Chavez-Crooker, P.; Farias, J.G.

    2013-01-01

    The mining industry is looking forward for bacterial consortia for economic extraction of copper from low-grade ores. The main objective was to determine an optimal bacterial consortium from several bacterial strains to obtain copper from the leach of chalcopyrite. The major native bacterial species involved in the bioleaching of sulphide ore (Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Leptospirillum ferrooxidans and Leptospirillum ferriphilum) were isolated and the assays were performed with individual bacteria and in combination with At. thiooxidans. In conclusion, it was found that the consortium integrated by At. ferrooxidans and At. thiooxidans removed 70% of copper in 35 days from the selected ore, showing significant differences with the other consortia, which removed only 35% of copper in 35 days. To validate the assays was done an escalation in columns, where the bacterial consortium achieved a higher percentage of copper extraction regarding to control. PMID:24294251

  19. Bacterial consortium for copper extraction from sulphide ore consisting mainly of chalcopyrite

    Directory of Open Access Journals (Sweden)

    E. Romo

    2013-01-01

    Full Text Available The mining industry is looking forward for bacterial consortia for economic extraction of copper from low-grade ores. The main objective was to determine an optimal bacterial consortium from several bacterial strains to obtain copper from the leach of chalcopyrite. The major native bacterial species involved in the bioleaching of sulphide ore (Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Leptospirillum ferrooxidans and Leptospirillum ferriphilum were isolated and the assays were performed with individual bacteria and in combination with At. thiooxidans. In conclusion, it was found that the consortium integrated by At. ferrooxidans and At. thiooxidans removed 70% of copper in 35 days from the selected ore, showing significant differences with the other consortia, which removed only 35% of copper in 35 days. To validate the assays was done an escalation in columns, where the bacterial consortium achieved a higher percentage of copper extraction regarding to control.

  20. Effects of impeller speed and aeration rate on flotation performance of sulphide ore

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effects of aeration rate and impeller speed on the concentrate sulfur grade and recovery for batch flotation of a complex sulphide ore were investigated. The relationships between the water recovery and solid entrainment were discussed. It is found that the solid entrainment is linearly related to the water recovery regardless of aeration rate and impeller speed, and the higher sulfur recovery at the aeration rate of 2 and 4 L/min for the impeller speed of 1 500 r/min is considered to be the contribution of true flotation. Finally, the sulfur recovery flux is correlated with the bubble surface area flux based on the froth image at the different aeration rates and impeller speeds.

  1. Gallium-lanthanum-sulphide amorphous thin films prepared by pulsed laser deposition

    International Nuclear Information System (INIS)

    Thin amorphous gallium-lanthanum-sulphide films were prepared by pulsed laser deposition method. The prepared layers were characterized in terms of the structure (using Raman scattering spectroscopy), chemical composition (by energy-dispersive X-ray analysis), and optical properties (employing variable angle spectroscopic ellipsometry). Following Raman spectroscopy results, it is supposed that the structure of the bulk glass and corresponding thin films is formed by GaS4 tetrahedra and LaS8 structural units. The study of photo- and thermally induced phenomena in prepared amorphous chalcogenides shows photoinduced decrease of refractive index (∼1-2%) under cw (473 nm) or pulsed (248 nm) laser irradiation and annealing-induced decrease of refractive index (∼2%), respectively.

  2. Gallium-lanthanum-sulphide amorphous thin films prepared by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Nemec, P., E-mail: Petr.Nemec@upce.cz [Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Legions Sq. 565, 53210 Pardubice (Czech Republic); Nazabal, V., E-mail: virginie.nazabal@univ-rennes1.fr [Equipe Verres et Ceramiques, UMR-CNRS 6226, Sciences Chimiques de Rennes (SCR), Universite de Rennes 1, 35042 Rennes (France); Pavlista, M., E-mail: martin.pavlista@upce.cz [Department of Physics, Faculty of Chemical Technology, University of Pardubice, Studentska 84, 53210 Pardubice (Czech Republic); Moreac, A., E-mail: alain.moreac@univ-rennes1.fr [GMCM, UMR-CNRS 6626, Universite de Rennes 1, 35042 Rennes (France); Frumar, M., E-mail: miloslav.frumar@upce.cz [Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Legions Sq. 565, 53210 Pardubice (Czech Republic); Vlcek, M., E-mail: milan.vlcek@upce.cz [Joint Laboratory of Solid State Chemistry of the University of Pardubice and the Institute of Macromolecular Chemistry of Acad. Sci. of the Czech Republic, Studentska 84, 53210 Pardubice (Czech Republic)

    2009-09-15

    Thin amorphous gallium-lanthanum-sulphide films were prepared by pulsed laser deposition method. The prepared layers were characterized in terms of the structure (using Raman scattering spectroscopy), chemical composition (by energy-dispersive X-ray analysis), and optical properties (employing variable angle spectroscopic ellipsometry). Following Raman spectroscopy results, it is supposed that the structure of the bulk glass and corresponding thin films is formed by GaS{sub 4} tetrahedra and LaS{sub 8} structural units. The study of photo- and thermally induced phenomena in prepared amorphous chalcogenides shows photoinduced decrease of refractive index ({approx}1-2%) under cw (473 nm) or pulsed (248 nm) laser irradiation and annealing-induced decrease of refractive index ({approx}2%), respectively.

  3. AN APPLICATION OF FLOW INJECTION ANALYSIS WITH GAS DIFFUSION AND SPECTROPHOTOMETRIC DETECTION FOR THE MONITORING OF DISSOLVED SULPHIDE CONCENTRATION IN ENVIRONMENTAL SAMPLES

    Directory of Open Access Journals (Sweden)

    Malwina Cykowska

    2014-10-01

    Full Text Available The monitoring of the concentration of sulphide is very important from the environment point of view because of high toxicity of hydrogen sulphide. What is more hydrogen sulphide is an important pollution indicator. In many cases the determination of sulphide is very difficult due to complicated matrix of some environmental samples, which causes that most analytical methods cannot be used. Flow injection analysis allows to avoid matrix problem what makes it suitable for a wide range of applications in analytical laboratories. In this paper determination of dissolved sulphide in environmental samples by gas-diffusion flow injection analysis with spectrophotometric detection was presented. Used gas-diffusion separation ensures the elimination of interferences caused by sample matrix and gives the ability of determination of sulphides in coloured and turbid samples. Studies to optimize the measurement conditions and to determine the value of the validation parameters (e.g. limit of detection, limit of quantification, precision, accuracy were carried out. Obtained results confirm the usefulness of the method for monitoring the concentration of dissolved sulphides in water and waste water. Full automation and work in a closed system greatly reduces time of analysis, minimizes consumption of sample and reagents and increases safety of analyst’s work.

  4. Fabrication, thermal and electrical properties of polyphenylene sulphide/copper composites

    International Nuclear Information System (INIS)

    Highlights: → Polyphenylene sulphide/copper composites show a low percolation threshold, i.e., about 6 vol% Cu. → Both pre- and post- glass transition coefficient of thermal expansion (CTE) of composites decreased significantly. → The microhardness was increased by more than 50% compared to pure PPS matrix. → The electrical conductivity was increased by about eight orders of magnitude for 18 vol% Cu composite. → Dielectric constant and dissipation factor of composites measured at MHz was increased to about 6-fold and 70-fold compared to PPS matrix. - Abstract: The thermal and electrical properties of high performance poly(phenylene sulphide) (PPS) composites reinforced up to 31 vol% Cu particles were investigated to be used as materials for electronic applications. The thermal stability and char yield of the composites increased significantly. Both pre- and post- glass transition coefficient of thermal expansion (CTE) of composites decreased significantly. The microhardness was increased by more than 50% compared to pure PPS matrix. Microhardness and CTE of composites correlated well with the rule of mixtures. A percolation threshold about 6 vol% Cu was obtained. The electrical conductivity was increased by about eight orders of magnitude for 18 vol% composite. Dielectric constant and dissipation factor of composites at 1 MHz was increased by about 6-fold and 70-fold compared to matrix, respectively. They decreased gradually with increasing frequency up to 1 MHz and thereafter, there was insignificant change. The scanning electron microscope showed almost uniform distribution of Cu particles in the matrix. Owing to better dimensional stability and good electrical properties, these composites are very promising for electronic applications.

  5. Hydrogen sulphide in the RVLM and PVN has no effect on cardiovascular regulation

    Directory of Open Access Journals (Sweden)

    Eloise eStreeter

    2011-09-01

    Full Text Available Hydrogen Sulphide (H2S is now recognised as an important signalling molecule and has been shown to have vasodilator and cardio-protectant effects. More recently it has been suggested that H2S may also act within the brain to reduce blood pressure. In the present study we have demonstrated the presence of the H2S producing enzyme, cystathionine  synthase (CBS in the rostral ventrolateral medulla (RVLM and the hypothalamic paraventricular nucleus (PVN, brain regions with key cardiovascular regulatory functions. The cardiovascular role of H2S was investigated by determining the blood pressure (BP, heart rate (HR and lumbar sympathetic nerve activity (LSNA responses elicited by a H2S donor (NaHS, sodium hydrogen sulphide or inhibitors of CBS, microinjected into the RVLM and PVN. In anaesthetised WKY rats bilateral microinjections of NaHS (0.2 – 2000 pmol/side into the RVLM did not significantly affect BP, HR or LSNA, compared to vehicle. Similarly, when the CBS inhibitors, amino-oxyacetate (AOA (0.1 – 1.0 nmol/side or hydroxylamine (HA (0.2 – 2.0 nmol/side, were administered into the RVLM, there were no significant effects on the cardiovascular variables compared to vehicle. Microinjections into the PVN of NaHS, HA and AOA had no consistent significant effects on BP, HR or LSNA compared to vehicle. We also investigated the cardiovascular responses to NaHS microinjected into the RVLM and PVN in SHR rats. Again, there were no significant effects on BP, HR and LSNA. Together, these results suggest that H2S in the RVLM and PVN does not have a major role in cardiovascular regulation.

  6. Influence of methanethiol on biological sulphide oxidation in gas treatment system.

    Science.gov (United States)

    Roman, Pawel; Bijmans, Martijn F M; Janssen, Albert J H

    2016-01-01

    Inorganic and organic sulphur compounds such as hydrogen sulphide (H2S) and thiols (RSH) are unwanted components in sour gas streams (e.g. biogas and refinery gases) because of their toxicity, corrosivity and bad smell. Biological treatment processes are often used to remove H2S at small and medium scales (<50 tons per day of H2S). Preliminarily research by our group focused on achieving maximum sulphur production from biological H2S oxidation in the presence of methanethiol. In this paper the underlying principles have been further studied by assessing the effect of methanethiol on the biological conversion of H2S under a wide range of redox conditions covering not only sulphur but also sulphate-producing conditions. Furthermore, our experiments were performed in an integrated system consisting of a gas absorber and a bioreactor in order to assess the effect of methanethiol on the overall gas treatment efficiency. This study shows that methanethiol inhibits the biological oxidation of H2S to sulphate by way of direct suppression of the cytochrome c oxidase activity in biomass, whereas the oxidation of H2S to sulphur was hardly affected. We estimated the kinetic parameters of biological H2S oxidation that can be used to develop a mathematical model to quantitatively describe the biodesulphurization process. Finally, it was found that methanethiol acts as a competitive inhibitor; therefore, its negative effect can be minimized by increasing the enzyme (biomass) concentration and the substrate (sulphide) concentration, which in practice means operating the biodesulphurization systems under low redox conditions.

  7. Improvement of cadmium phytoremediation after soil inoculation with a cadmium-resistant Micrococcus sp.

    Science.gov (United States)

    Sangthong, Chirawee; Setkit, Kunchaya; Prapagdee, Benjaphorn

    2016-01-01

    Cadmium-resistant Micrococcus sp. TISTR2221, a plant growth-promoting bacterium, has stimulatory effects on the root lengths of Zea mays L. seedlings under toxic cadmium conditions compared to uninoculated seedlings. The performance of Micrococcus sp. TISTR2221 on promoting growth and cadmium accumulation in Z. mays L. was investigated in a pot experiment. The results indicated that Micrococcus sp. TISTR2221significantly promoted the root length, shoot length, and dry biomass of Z. mays L. transplanted in both uncontaminated and cadmium-contaminated soils. Micrococcus sp. TISTR2221 significantly increased cadmium accumulation in the roots and shoots of Z. mays L. compared to uninoculated plants. At the beginning of the planting period, cadmium accumulated mainly in the shoots. With a prolonged duration of cultivation, cadmium content increased in the roots. As expected, little cadmium was found in maize grains. Soil cadmium was significantly reduced with time, and the highest percentage of cadmium removal was found in the bacterial-inoculated Z. mays L. after transplantation for 6 weeks. We conclude that Micrococcus sp. TISTR2221 is a potent bioaugmenting agent, facilitating cadmium phytoextraction in Z. mays L.

  8. Cadmium Modulates Biofilm Formation by Staphylococcus epidermidis

    NARCIS (Netherlands)

    Wu, Xueqing; Santos, Regiane R.; Fink-Gremmels, Johanna

    2015-01-01

    The aim of the study was to evaluate the effect of cadmium exposure on Staphylococcus epidermidis (ATCC 35984) biofilm formation. Bacteria were cultured in the absence or presence of different concentrations (0-50 mu M) of cadmium. Biofilm formation and bacterial viability were assessed. Quantitativ

  9. The Impact of CdS Nanoparticles on Ploidy and DNA Damage of Rucola (Eruca sativa Mill. Plants

    Directory of Open Access Journals (Sweden)

    Inese Kokina

    2015-01-01

    Full Text Available The genotoxic effect of cadmium sulfide nanoparticles (CdS NPs of different sizes in rucola (Eruca sativa Mill. plants was assessed. It was confirmed that nanoparticles < 5 nm in size were more toxic than larger particles at an identical mass concentration. Significant differences in cell ploidy, as well as in the mitotic index, were detected between control and treated samples. Differences in the DNA banding pattern between control samples and samples after treatment with cadmium sulfide nanoparticles were significant and detected at different places as the appearance or elimination of DNA fragments. Fluorescence images showed that cadmium sulfide nanoparticles smaller than 5 nm in size can diffuse through the membrane and their presence affects the genetic system of the plant.

  10. Cadmium stress in wheat seedlings: growth, cadmium accumulation and photosynthesis

    DEFF Research Database (Denmark)

    Ci, Dunwei; Jiang, Dong; Wollenweber, Bernd;

    2010-01-01

    Seedlings of wheat (Triticum aestivum L.) cultivars Jing 411, Jinmai 30 and Yangmai 10 were exposed to 0, 10, 20, 30, 40 or 50 μM of CdCl2 in a solution culture experiment. The effects of cadmium (Cd) stress on wheat growth, leaf photon energy conversion, gas exchange, and Cd accumulation in wheat...... parameters were generally depressed by Cd stress, especially under the high Cd concentrations. Cd concentration and accumulation in both shoots and roots increased with increasing external Cd concentrations. Relationships between corrected parameters of growth, photosynthesis and fluorescence and corrected...

  11. Immunoassay for Cadmium Detection and Quantification

    Institute of Scientific and Technical Information of China (English)

    GONG-LIANG LIU; JU-FANG WANG; ZHI-YONG LI; SHI-ZHONG LIANG; XIAO-NING WANG

    2009-01-01

    Objective To detect cadmium in environmental and food samples by graphite furnace atomic absorption spectroscopy (GFAAS) and inductively coupled plasma atomic emission spectroscopy (ICPAES). Methods An indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) was developed based on a cadmium-specific monoclonal antibody.IC-ELISA for cadmium in environmental and food samples was evaluated. Results IC-ELISA showed an IC50 of 45.6 μg/L with a detection limit of 1.95 μg/L for cadmium,and showed a mean recovery ranging 97.67%-107.08%.The coefficient of variations for intra- and iuterassay was 3.41%-6.61% and 4.70%-9.21%,respectively.The correlation coefficient between IC-ELISA and GFAAS was 0.998. Conclusion IC-ELISA can detect and quantify cadmium residue in environmental or food samples.

  12. Cadmium mobility and accumulation in soils of the European Communities

    NARCIS (Netherlands)

    Fraters B; van Beurden AUCJ

    1993-01-01

    In this overview of the effects of cadmium pollution on agricultural soils in the European Community, both the cadmium loads on agricultural land and the soil sensitivity to cadmium accumulation have been estimated. Cadmium loads have been estimated separately for arable land and grassland. The ef

  13. Studies on Characterization, Optical Absorption, and Photoluminescence of Yttrium Doped ZnS Nanoparticles

    Directory of Open Access Journals (Sweden)

    Ranganaik Viswanath

    2014-01-01

    Full Text Available Pure ZnS and ZnS:Y nanoparticles were synthesized by a chemical coprecipitation route using EDTA-ethylenediamine as a stabilizing agent. X-ray diffraction (XRD, high resolution transmission electron microscopy (HRTEM, field emission scanning electron microscopy (FE-SEM, Fourier transform infrared spectrometry (FTIR, thermogravimetric-differential scanning calorimetry (TG-DSC, and UV-visible and photoluminescence (PL spectroscopy were employed to characterize the as-synthesized ZnS and ZnS:Y nanoparticles, respectively. XRD and TEM studies show the formation of cubic ZnS:Y particles with an average size of ~4.5 nm. The doping did not alter the phase of the zinc sulphide, as a result the sample showed cubic zincblende structure. The UV-visible spectra of ZnS and ZnS:Y nanoparticles showed a band gap energy value, 3.85 eV and 3.73 eV, which corresponds to a semiconductor material. A luminescence characteristics such as strong and stable visible-light emissions in the orange region alone with the blue emission peaks were observed for doped ZnS nanoparticles at room temperature. The PL intensity of orange emission peak was found to be increased with an increase in yttrium ions concentration by suppressing blue emission peaks. These results strongly propose that yttrium doped zinc sulphide nanoparticles form a new class of luminescent material.

  14. Peculiarities of preparation of cadmium isotopes of high enrichment

    International Nuclear Information System (INIS)

    Cascade equipped by gas centrifuges with regard for requirements to structural materials operating with chemically active compounds (dimethylcadmium) was devised for preparation of high-enriched cadmium isotopes. Solutions of such problems as overcoming of isotope memory, compensation of the effect of isotope overlapping, operative analytical accompanying permitted to optimize separation process and to obtain cadmium isotopes of high enrichment degree: cadmium-116 ∼98.9 %, cadmium-114 ∼98.7 %, cadmium-113 ∼93.3 %, cadmium-112 ∼99.1 %, cadmium-110 ∼95.8 %

  15. Induction of Localized Hyperthermia by Millisecond Laser Pulses in the Presence of Gold-Gold Sulphide Nanoparticles in a Phantom

    Directory of Open Access Journals (Sweden)

    Zahra Shahamat

    2015-05-01

    Full Text Available Introduction Application of near-infrared absorbing nanostructures can induce hyperthermia, in addition to providing more efficient  photothermal effects. Gold-gold sulfide (GGS is considered as one of these nanostructures. This study was performed on a tissue-equivalent optical-thermal phantom to determine the temperature profile in the presence and absence of GGS and millisecond pulses of a near-infrared laser. Moreover, the feasibility of hyperthermia induction was investigated in a simulated tumor. Materials and Methods A tumor with its surrounding tissues was simulated in a phantom made of Agarose and Intralipid. The tumor was irradiated by 30 laser pulses with durations of 30, 100, and 400 ms and fluences of 40 and 60 J/cm2. Temperature variations in the phantom with and without GGS were recorded, using fast-response sensors of a digital thermometer, placed at different distances from the central axis at three depths. The temperature rise was recorded by varying duration and fluence of the laser pulses. Results The rise in temperature was recorded by increasing laser fluence and number of pulses for three durations. The temperature profile was obtained at each depth. The presence of GGS resulted in a significant increase in temperature in all cases (P

  16. 187Re- 187Os Nuclear Geochronometry: Dating Peridotitic Diamond Sulphide Inclusions

    Science.gov (United States)

    Roller, Goetz

    2015-04-01

    Nuclear geochronometry [1-2] is a new dating method which combines principles of geochronology with nuclear astrophysics. It is embedded in other scientific fields like cosmochemistry, cosmology and nuclear theory, which pose tight constraints for nuclear geochronometry. It is based upon identified Re/Os element ratios ˜ 1, interpreted as the nuclear production ratio, and ultra-subchondritic initial 187Os/188Os ratios within terrestrial rocks, suggesting that Earth's core still contains element ratios and isotopic signatures of at least two rapid (r) neutron-capture process [3] events. The 13.78 Ga old component, represented by the isotopic signature of a komatiitic basalt [5085 BasKom] [4] from the Barberton Greenstone Belt (Onverwacht Group, South Africa), is assigned to the Earth's inner core. The other isotopic signatures identified so far within pyroxenites / komatiites are assigned to its outer core due to at least one gravitational collapse of the old component, commencing ˜ 3.48 Ga [2] and resulting in one or more additional r-process event(s). Here I show that 187Re-187Os nuclear geochronometry can also be successfully applied for dating peridotitic diamond sulphide inclusions by means of two-point-isochrones (TPI), using a so-called nuclear geochronometer always as the second data point in a TPI diagram. It turns out that the method may have a huge potential to constrain the chemical evolution of the SCLM. For example, TPI ages for Ellendale (Australia) peridotitic diamond sulphide inclusions EL50, EL23, EL54-1, EL54-3, EL55-1 and EL65 reported in the literature [5] reveal at least two main fractionation events. The age cluster between 1.4 Ga and 1.5 Ga is consistent with a previously reported isochrone age [5]. The event ˜ 2.3 ± 0.3 Ga overlaps the Great Oxidation Event (GOE) between 2.22 Ga and 2.46 Ga. While the ˜ 1.4 Ga to 1.5 Ga events lead to fractionation of the 187Re/188Os ratios towards values typical for mantle peridotite, the latter caused

  17. The leaching behaviour of a Ni-Cu-Co sulphide ore in an oxidative pressure-acid medium / Danie Strydom Smit

    OpenAIRE

    Smit, Danie Strydom

    2001-01-01

    Hydrometallurgical processing of sulphide concentrates is an attractive method for the selective extraction of valuable metals. The dissolution of minerals in a leaching process involves several electrochemical parameters that need to be investigated• to ensure the development and growth of the base metal industry in South Africa. A study has been carried out to elucidate the leaching mechanism of a nickel-coppercobalt sulphide concentrate in an oxidative pressure-acid medium. ...

  18. High and intermediate sulphidation environment in the same hydrothermal deposit: the example of Au-Cu Palai???Islica deposit, Carboneras (Almer??a)

    OpenAIRE

    Carrillo-Ros??a, Javier; Morales-Ruano, Salvador; Boyce, Adrian J.; Fallick, Anthony E.

    2003-01-01

    Two epithermal environments have been identified in the Miocene Palai???Islica Au???Cu deposit: A) Intermediate sulphidation, hosted mainly in quartz veins, comprises pyrite, chalcopyrite, sphalerite and galena as the major sulphides, which are accompanied by a variety of Ag-bearing accessory minerals. Au???Ag alloys are the only gold-bearing phase. The veins are enclosed by sericitic and chloritic alteration. Fluid inclusions in quartz, sphalerite and calcite give Th between 118???453 ??C, a...

  19. Assessment of the flotability of chalcopyrite, molybdenite and pyrite using biosolids and their main components as collectors for greening the froth flotation of copper sulphide ores.

    OpenAIRE

    Sobarzo, Francisco; Herrera Urbina, Ronaldo; Higueras Higueras, Pablo Leon; SÁez Navarrete, CÉsar; Godoy FaÚndez, Alex; Reyes Bozo, Lorenzo; VÁsquez Bestagno, Jorge

    2014-01-01

    Biosolids and representative compounds of their main components ? humic acids, sugars, and proteins ? have been tested as possible environment-friendly collectors and frothers for the flotation of copper sulphide ores. The floatability of chalcopyrite and molybdenite ? both valuable sulphide minerals present in these ores ? as well as non-valuable pyrite was assessed through Hallimond tube flotation tests. Humic acids exhibit similar collector ability for chalcopyrite and molybdenite as that ...

  20. Conversion of calcium sulphide to calcium carbonate during the process of recovery of elemental sulphur from gypsum waste.

    Science.gov (United States)

    de Beer, M; Maree, J P; Liebenberg, L; Doucet, F J

    2014-11-01

    The production of elemental sulphur and calcium carbonate (CaCO3) from gypsum waste can be achieved by thermally reducing the waste into calcium sulphide (CaS), which is then subjected to a direct aqueous carbonation step for the generation of hydrogen sulphide (H2S) and CaCO3. H2S can subsequently be converted to elemental sulphur via the commercially available chemical catalytic Claus process. This study investigated the carbonation of CaS by examining both the solution chemistry of the process and the properties of the formed carbonated product. CaS was successfully converted into CaCO3; however, the reaction yielded low-grade carbonate products (i.e. 99 mass% as CaCO3) or precipitated calcium carbonate (PCC).

  1. Multiple hydrothermal and metamorphic events in the Kidd Creek volcanogenic massive sulphide deposit, Timmins, Ontario: evidence from tourmalines and chlorites

    Science.gov (United States)

    Slack, J.F.; Coad, P.R.

    1989-01-01

    The tourmalines and chlorites record a series of multiple hydrothermal and metamorphic events. Paragenetic studies suggest that tourmaline was deposited during several discrete stages of mineralization, as evidence by brecciation and cross-cutting relationships. Most of the tourmalines have two concentric growth zones defined by different colours (green, brown, blue, yellow). Some tourmalines also display pale discordant rims that cross-cut and embay the inner growth zones and polycrystalline, multiple-extinction domains. Late sulphide veinlets (chalcopyrite, pyrrhotite) transect the inner growth zones and pale discordant rims of many crystals. The concentric growth zones are interpreted as primary features developed by the main ore-forming hydrothermal system, whereas the discordant rims, polycrystalline domains, and cross-cutting sulphide veinlets reflect post-ore metamorphic processes. Variations in mineral proportions and mineral chemistry within the deposit mainly depend on fluctuations in temperature, pH, water/rock ratios, and amounts of entrained seawater. -from Authors

  2. Relationships between basin architecture, basin closure, and occurrence of sulphide-bearing schists: an example from Tampere Schist Belt, Finland

    DEFF Research Database (Denmark)

    Kalliomäki, Henrik; Torvela, Taija; Moreau, Julien;

    The Tampere Schist Belt (TSB) in southern Finland is a c. 1.92-1.88 Ga volcano-sedimentary basin that underwent inversion and closure between c. 1.89-1.88 Ga. We present field observations from the Tampere palaeobasin, where the primary structures have been exceptionally well preserved. The TSB......, therefore, offers an excellent opportunity to examine the volcano-sedimentary evolution of an ancient marginal basin, and the mechanics of and strain distribution during its subsequent closure. The aim of this study is to investigate the structural development and the architecture of a part of the TSB...... in more detail, including the relationships between the volcano-sedimentary sequences, the tectonic structures, and the sulphide-bearing schist horizons. Important insights are gained into understanding the mechanisms of the basin closure and the localisation of the sulphide mineralisation within...

  3. Determination of sulphide concentrates of ore copper by XRPD and chemical analysis

    Directory of Open Access Journals (Sweden)

    Cocić Mira B.

    2009-01-01

    Full Text Available Roasting process of sulphide copper concentrates in fluo-solid reactor is an oxidation process, and presents the first stage of copper concentrate processing in Copper Mining and Smelting Complex Bor, RTB Bor. Therefore, the importance of accurate and up to date process control is an apparent precondition for the correct treatment in the following stages and also for of high grade cathode copper. As concentrate is fed into the roaster, it is heated by a stream of hot air to about 590°C. The process takes place between solid and gaseous phases without the appearance of a liquid phase. The heat generated by the exothermic oxidation reaction of sulphur from cooper and iron minerals (chalcopyrite and pyrite is sufficient to carry out the entire process autogenously at temperature from 620 to 670°C. The temperature of sulphur firing which defines the start of roasting depends on physical traits, particle size of sulfides and characteristic product of oxidation. The obtained products of the roasting process are: calcine, ready for smelting in the furnace and gas-rich sulphure dioxide (SO2, well suited for the production of sulfuric acid. The relationship between the quantitative mineral composition of the charge and of the calcine directly points out to the efficiency of the roasting process in fluo-solid reactor. The amount of bornite and magnetite, resulting from the sulfide oxidation is the most important parameter. Hence, quantitative determination of mineral composition is of great interest. In this work, the results of the determination of quantitative mineral composition of the copper sulphide concentrate (charge and products of their roasting (calcine and overflow in fluo-solid reactor in the RTB Bor are presented. The aim was to compare the results of the iron, copper, sulfur and oxygen contents determined by two independent techniques, the chemical (HA and X-ray powder diffraction analysis (XRPD that is based on the quantitative mineral

  4. Radioguided sentinel node biopsy with 99mTc colloidal (Re) sulphide: Our experience

    International Nuclear Information System (INIS)

    Full text: It has been demonstrated that nodal metastases from different solid tumors are not random events. Tumour spread within the regional draining basin has been shown to progress in an orderly fashion with first draining basin (sentinel node) most likely to have metastatic involvement. Thus, the sentinel node examination accurately reflects the histology of the remainder of the lymphatic basin. Sentinel node biopsy (SLB) with previous lymphatic mapping by means of radiocolloid lymphoscintraphy has been proposed by many authors as a routine method for staging the regional lymph nodes in patients with cutaneous melanoma and breast cancer. A positive SLB is found to carry high prognostic significance and identifies those patients who might benefit from early therapeutic lymph node dissection and adjuvant treatment. The aim of this retrospective study was to evaluate our experience with radioguided SLB in patients with different tumours. We studied 154 patients between 1998-2003, with clinically localized breast cancer (n=45), melanoma (n=82), cervix carcinoma (n=22) and penis carcinoma (n=5). Lymphoscintigraphy was performed 6-18 hours before surgery using a LFOV gamma camera equipped with a LEHR collimator. A dose of 111-185 MBq of 99mTc colloidal sulphide (Nanocis, Cis bio international, Gif-Sur-Yvette, France) was injected around the primary lesion (melanoma, breast cancer, and penis carcinoma) and into the four quadrants of the cervix (cervix carcinoma). All basins identified by lymphoscintigraphy were explored through incisions directed by the use of a gamma probe. Radioactivity (counts /sec) of the sentinel node(s) and the adjacent tissues was measured in-vivo and verified ex-vivo after removal. A signal to background ratio higher than 2 to 3 in-vivo and higher than 10 ex-vivo was considered significant. Blue dye mapping was performed in all cases of breast cancer but left at discretion of the surgeon for the remaining tumours. Serial sections of the

  5. Response of Saccharomyces cerevisiae to cadmium stress

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Luciana Mara Costa; Ribeiro, Frederico Haddad; Neves, Maria Jose [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Lab. de Radiobiologia], e-mail: luamatu@uol.com.br; Porto, Barbara Abranches Araujo; Amaral, Angela M.; Menezes, Maria Angela B.C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Lab. de Ativacao Neutronica], e-mail: menezes@cdtn.br; Rosa, Carlos Augusto [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Microbiologia], e-mail: carlrosa@icb.ufmg

    2009-07-01

    The intensification of industrial activity has been greatly contributing with the increase of heavy metals in the environment. Among these heavy metals, cadmium becomes a serious pervasive environmental pollutant. The cadmium is a heavy metal with no biological function, very toxic and carcinogenic at low concentrations. The toxicity of cadmium and several other metals can be mainly attributed to the multiplicity of coordination complexes and clusters that they can form. Some aspects of the cellular response to cadmium were extensively investigated in the yeast Saccharomyces cerevisiae. The primary site of interaction between many toxic metals and microbial cells is the plasma membrane. Plasma-membrane permeabilisation has been reported in a variety of microorganisms following cadmium exposure, and is considered one mechanism of cadmium toxicity in the yeast. In this work, using the yeast strain S. cerevisiae W303-WT, we have investigated the relationships between Cd uptake and release of cellular metal ions (K{sup +} and Na{sup +}) using neutron activation technique. The neutron activation was an easy, rapid and suitable technique for doing these metal determinations on yeast cells; was observed the change in morphology of the strains during the process of Cd accumulation, these alterations were observed by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) during incorporation of cadmium. (author)

  6. Response of Pleurotus ostreatus to cadmium exposure

    Energy Technology Data Exchange (ETDEWEB)

    Favero, N.; Bressa, G.; Costa, P. (Univ. of Padua (Italy))

    1990-08-01

    The possibility of utilizing agroindustrial wastes in the production of edible, high-quality products (e.g., mushrooms) implies the risk of bringing toxic substances, such as heavy metals, into the human food chain. Thus, growth in the presence of cadmium and cadmium accumulation limits have been studied in the industrially cultivated fungus P. ostreatus. Fruit body production is substantially unaffected in the presence of 25, 139, and 285 mg Cd/kg of dried substrate. Cadmium concentration in fruit bodies is related to cadmium substrate level, the metal being present at higher levels in caps (22-56 mg/kg dry wt) than in stems (13-36 mg/kg dry wt). Concentration factor (CF), very low in the controls (about 2), further decreases in treated specimens. The presence of a cadmium control mechanism in this fungi species is suggested. Fruit body cadmium levels could, however, represent a risk for P. ostreatus consumers, according to FAO/WHO limits related to weekly cadmium intake.

  7. An ion probe study of the sulphur isotopic composition of Fe-Ni sulphides in CM carbonaceous chondrites

    OpenAIRE

    Bullock, E. S.; McKeegan, K. D.; Gounelle, M.; Grady, M. M.; Russell, S.S

    2004-01-01

    From the Introduction: The CM chondrites have endured variable degrees of aqueous alteration [1] which has changed their original mineralogy. A detailed study of the petrology and mineralogy of the sulphides in a suite of increasingly aqueously altered CMs, combined with sulphur isotope data measured in situ, can provide clues as to whether differences in the CM group are a result of different degrees of aqueous alteration, or whether they are the result of nebular heterogeneity.

  8. Municipal sewer networks as sources of nitrous oxide, methane and hydrogen sulphide emissions : a review and case studies

    OpenAIRE

    Eijo Rio, Elena; Petit, Anna; Villalba Mendez, Gara; Suárez-Ojeda, María Eugenia; Rieradevall, Joan; Gabarrell Durany, Xavier; Marín, Desirée; Amores, Maria José; Aldea, Xavier

    2015-01-01

    Sewers are known as longitudinal reactors where gases such as methane, nitrous oxide and hydrogen sulphide can be produced. However, gaseous emissions have been mainly assessed in wastewater treatment plants (WWTP). This article presents a critical review of studies that quantify the generation of these gases in sewers and aims to identify the existing research gaps. Differences in sampling methods and site selection, as well as a limited number of studies, result in incoherent comparisons. T...

  9. Structural, optical and dielectric properties of lead doped ZnS nanoparticles

    Science.gov (United States)

    Virpal; Hastir, Anita; Sharma, Sandeep; Singh, Ravi Chand

    2016-05-01

    Pure and lead doped ZnS nanoparticles have been successfully synthesized by chemical precipitation method. Structural analysis using X-ray diffraction confirms the cubic phase of ZnS and formation of an additional cubic phase of lead sulphide in lead doped ZnS nanoparticles. Increase in the band gap of the doped nanoparticles is consistent with the reduction of crystallite size which lies in the quantum confinement regime. A broad green emission was observed in photoluminescence spectra of lead doped ZnS nanoparticles. The green emission arises due to the presence of lead ions at zinc lattice sites in the host lattice of ZnS. Dielectric measurements reveal that dielectric constant is higher for the doped samples indicating that value of the dielectric constant can be tuned by adding suitable amount of the dopant although dielectric losses in these samples are higher and further investigations are required.

  10. Geochemical, metagenomic and metaproteomic insights into trace metal utilization by methane-oxidizing microbial consortia in sulphidic marine sediments

    Energy Technology Data Exchange (ETDEWEB)

    Glass, DR. Jennifer [California Institute of Technology, Pasadena; Yu, DR. Hang [California Institute of Technology, Pasadena; Steele, Joshua [California Institute of Technology, Pasadena; Dawson, Katherine [California Institute of Technology, Pasadena; Sun, S [University of California, San Diego; Chourey, Karuna [ORNL; Pan, Chongle [ORNL; Hettich, Robert {Bob} L [ORNL; Orphan, V [California Institute of Technology, Pasadena

    2013-01-01

    Microbes have obligate requirements for trace metals in metalloenzymes that catalyse important biogeochemical reactions. In anoxic methane- and sulphiderich environments, microbes may have unique adaptations for metal acquisition and utilization because of decreased bioavailability as a result of metal sulphide precipitation. However, micronutrient cycling is largely unexplored in cold ( 10 C) and sulphidic (> 1 mM H2S) deep-sea methane seep ecosystems. We investigated trace metal geochemistry and microbial metal utilization in methane seeps offshore Oregon and California, USA, and report dissolved concentrations of nickel (0.5 270 nM), cobalt (0.5 6 nM), molybdenum (10 5600 nM) and tungsten (0.3 8 nM) in Hydrate Ridge sediment porewaters. Despite low levels of cobalt and tungsten, metagenomic and metaproteomic data suggest that microbial consortia catalysing anaerobic oxidation of methane (AOM) utilize both scarce micronutrients in addition to nickel and molybdenum. Genetic machinery for cobalt-containing vitamin B12 biosynthesis was present in both anaerobic methanotrophic archaea (ANME) and sulphate-reducing bacteria. Proteins affiliated with the tungsten-containing form of formylmethanofuran dehydrogenase were expressed in ANME from two seep ecosystems, the first evidence for expression of a tungstoenzyme in psychrophilic microorganisms. Overall, our data suggest that AOM consortia use specialized biochemical strategies to overcome the challenges of metal availability in sulphidic environments.

  11. The environmental context of Acidithiobacillus ferrooxidans and its potential role as an ecosystem engineer in sulphidic mine waste

    Energy Technology Data Exchange (ETDEWEB)

    Ebenaa, Gustav

    2001-06-01

    Microorganisms are the causative agent of the environmental problems since they catalyse the weathering of the (sulphidic) waste. The chemical oxidation alone is not fast enough to create any severe environmental problems. Acidithiobacillus ferrooxidans is thought to be a key organism in weathering of sulphide minerals. A. ferrooxidans is affected by several more or less abiotic factors. The influence of temperature, pH and nutrient deficiency as potentially limiting factors for the activity of A. ferrooxidans has been investigated. It seems that temperature has less influence on its activity, but rather reflects the origin of the bacterial isolate. An alkaline pH seems enough to hinder growth and activity. The nutrients do not seem to be a limiting factor in the studied environment. The possible regulation of the activity of A. ferrooxidans is therefore a way to, at least partly, mitigate the environmental impact from mine waste. Waste from the mining industry is the largest waste problem in Sweden. With amounts over 600 million tonnes one could easily imagine the tremendous cost involved in the abatement. The MiMi-programme, with researchers from several relevant fields, has as its aim to evaluate present and to find alternative techniques to mitigate the environmental impact from mine waste. The understanding of A. ferrooxidans and its role as an ecosystem engineer is essential both in evaluating present techniques and even more so in finding alternative abatement techniques for sulphidic mine waste.

  12. Cadmium Toxicity to Ringed Seals (Phoca hispida)

    DEFF Research Database (Denmark)

    Sonne, Christian; Dietz, R.; Riget, F. F.;

    as laboratory mammals. We have studied possible cadmium induced histopathological changes in the kidneys as well as a demineralisation of the skeletal system (DXA-scanning of lumbal vertebraes). No obvious cadmium induced toxic changes were found. Food composition and physiological adaptations may explain......Cadmium concentrations in kidneys from ringed seals (Phoca hispida) from North West Greenland (Qaanaaq) are high. Concentrations range at level known to induce renal toxic effects (mainly tubulopathy) and demineralisation (osteopenia) of the skeletal system (Fanconi's Syndrome) in humans as well...

  13. Mechanistic insight into the nucleation and growth of oleic acid capped lead sulphide quantum dots.

    Science.gov (United States)

    Shrestha, Aabhash; Spooner, Nigel A; Qiao, Shi Zhang; Dai, Sheng

    2016-05-18

    The quantum dots (QDs) of lead sulphide (PbS) are attractive near-infrared (NIR) active materials and have promising applications in a wide variety of applications. Till date many efforts have been made on optimizing its synthesis; however, current mechanistic understanding involving the nucleation and growth of these QDs has not reached the same level as that for other QDs. In this study, we present a detailed understanding on synthesis mechanism of PbS QDs so as to provide guidance for future QDs synthesis. The synthesis of PbS QDs is largely independent of classical nucleation process and the hot-injection of precursors may not be necessary for the successful synthesis of PbS QDs. The synthesis is basically a growth dominated process and is controlled by the Ostwald ripening of PbS QDs. In addition, reaction temperature and ligand are the key parameters for controlling QD growth. Temperature provides energy for overcoming activation barrier of QD growth while the ligands enhance QD growth via altering the environment for QD growth. Following the mechanism governing the synthesis of PbS QDs, we demonstrate that the size tuning of PbS QDs in ultra-small (<2 nm) can be achieved, which has been typically challenging following the hot injection synthesis.

  14. Dibenzothiophene HDS over sulphided CoMo on high-silica USY zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Lara, G.; Escobar, J.; Murrieta, F.R. [Mexican Inst. of Petroleum, Madero (Mexico); De Los Reyes, J.A.; Barrera, M.C. [Univ. Autonoma Metropolitana, Iztapalapa (Mexico); Colin, J.A. [Univ. Autonoma Metropolitana, Azcapotzalco (Mexico)

    2005-08-01

    The sulphur content in oil-derived fuels will be severely limited in the near future due to stringent environmental regulations. The production of environmentally-sound diesel fuel containing less than 50 wppm of sulphur will be required worldwide by 2006. By 2008, that number will have to be reduced to about 10 wppm. These targets can be attained by using improved deep hydrodesulphurization (HDS) catalysts. This study involved a complete characterization of ultra-stable Y (USY) zeolites to determine their contribution as a hydrotreatment (HDT) catalyst additive. In particular USY faujasites were used as an HDS catalyst support. Molybdenum (Mo), cobalt (Co) and phosphorous (P) were impregnated at 2 concentrations. After impregnation, the surface acidity of the USY zeolites strongly decreased after Co-Mo-P deposition, for the conventional loading (CL) series materials and the high loading (HL) series materials. Sulphide catalysts were tested in dibenzothiophene (DBT) HDS at 320 degrees C and 5.59 MPa. The HDS rate was found to increase slightly with both SiO{sub 2} content and Co-Mo-P loading. High selectivity to hydrogenated products suggested deficient Mo promotion in CL solids. It was suggested that improved Mo promotion by Co in the HL series may be responsible for higher activity and marked selectivity to desulphurization to biphenyl. 36 refs., 2 tabs., 17 figs.

  15. Determination of iron sulphides in roofing slates from the north west of Spain

    Directory of Open Access Journals (Sweden)

    García-Guinea, J.

    2002-06-01

    Full Text Available The most important production of roofing slates in the world is quarried from the Ordovician formations of the Truchas Syncline, which have the largest amount of working quarries. Roofing slates, sometimes, have crystallized iron sulphides such as pyrite, pyrrhotite and other minerals. These iron sulphides oxidise and stain the tiles when are exposed to atmospheric conditions, so much oxidized how much more inclined is the roof. Galician quarrymen distinguish between harmless pyrite (i.e., resistant cubes of pyrite and damaging pyrite (i.e., other alterable metallic minerals such as pyrrhotite, chalcopyrite, marcasite and arsenopyirite. An improved identification method is proposed using both methods (a chemical element ratios of samples under electron microprobes and (b quantitative determination of the iron sulphides in the slate measuring the oxidized areas by digital camera. The analysed Fe/S ratios, in an XY plot, of seventy metallic samples, define three separated zones: pyrite, pyrrhotite and iron oxi-hydroxides. Quantitative determination of iron sulphides in the slate tile were performed by sinking the tile horizontally for six hours in oxygen peroxide (3% diluted and capturing the oxidation areas with a magnetic camera and analysing the bitmap images with Sigma-Scan 5 software. The proposed method is faster than the Spanish UNE norm (UNE-EN- 12326-2 Sept.2000, which requires thermal strike cycles for a month. The necessary use of heavy analytical equipment such as electron microprobes can be facilitated by installing it in the Slate Technological Centre of Sobradelo de Valdeorras (Orense or by using a simple optical stereoscopic zoom microscope to classify the iron minerals.

    Las formaciones ordovícicas del Sinclinal de Duchas concentran la mayor producción mundial de pizarra para cubiertas y el mayor número de canteras en producción. Las pizarras para cubiertas muchas veces contienen sulfuros de hierro cristalizados en forma

  16. From lithotroph- to organotroph-dominant: directional shift of microbial community in sulphidic tailings during phytostabilization

    Science.gov (United States)

    Li, Xiaofang; Bond, Philip L.; van Nostrand, Joy D.; Zhou, Jizhong; Huang, Longbin

    2015-08-01

    Engineering microbial diversity to enhance soil functions may improve the success of direct revegetation in sulphidic mine tailings. Therefore, it is essential to explore how remediation and initial plant establishment can alter microbial communities, and, which edaphic factors control these changes under field conditions. A long-term revegetation trial was established at a Pb-Zn-Cu tailings impoundment in northwest Queensland. The control and amended and/or revegetated treatments were sampled from the 3-year-old trial. In total, 24 samples were examined using pyrosequencing of 16S rRNA genes and various chemical properties. The results showed that the microbial diversity was positively controlled by soil soluble Si and negatively controlled by soluble S, total Fe and total As, implying that pyrite weathering posed a substantial stress on microbial development in the tailings. All treatments were dominated by typical extremophiles and lithotrophs, typically Truepera, Thiobacillus, Rubrobacter; significant increases in microbial diversity, biomass and frequency of organotrophic genera (typically Nocardioides and Altererythrobacter) were detected in the revegetated and amended treatment. We concluded that appropriate phytostabilization options have the potential to drive the microbial diversity and community structure in the tailings toward those of natural soils, however, inherent environmental stressors may limit such changes.

  17. Optical properties of silver sulphide thin films formed on evaporated Ag by a simple sulphurization method

    Energy Technology Data Exchange (ETDEWEB)

    Barrera-Calva, E., E-mail: ebc@xanum.uam.m [Departamento de Ingenieria de Procesos e hidraulica, Universidad Autonoma Metropolitana - Iztapalapa, Av. Purisima Esq. Michoacan, Col. Vicentina, Mexico, D.F., 09340 (Mexico); Ortega-Lopez, M.; Avila-Garcia, A.; Matsumoto-Kwabara, Y. [Departamento de Ingenieria Electrica, Centro de Investigacion y de Estudios Avanzados del IPN, Mexico DF 07360 (Mexico)

    2010-01-31

    Silver sulphide (Ag{sub 2}S) thin films were grown on the surface of silver films (Ag) deposited on glass substrate by using a simple chemical sulphurization method. According to X-ray diffraction analysis, the Ag{sub 2}S thin films display low intensity peaks at 34.48{sup o}, 36.56{sup o}, and 44.28{sup o}, corresponding to diffraction from (100), (112) and (103) planes of the acanthite phase (monoclinic). A model of the type Ag{sub 2}S/Ag/glass was deduced from spectroscopic ellipsometric measurements. Also, the optical constants (n, k) of the system were determined. Furthermore, the optical properties as solar selective absorber for collector applications were assessed. The optical reflectance of the Ag{sub 2}S/Ag thin film systems exhibits the expected behavior for an ideal selective absorber, showing a low reflectance in the wavelength range below 2 {mu}m and a high reflectance for wavelengths higher than that value. An absorptance about 70% and an emittance about 3% or less were calculated for several samples.

  18. Microwave-assisted total digestion of sulphide ores for multi-element analysis

    Energy Technology Data Exchange (ETDEWEB)

    Al-Harahsheh, M., E-mail: al-harahsheh@ahu.edu.jo [College of Mining and Environmental Engineering, Al-Hussein Bin Talal University, P.O. Box 20, Ma' an 71111 (Jordan); Kingman, S.; Somerfield, C. [Department of Chemical and Environmental Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Ababneh, F. [Department of Chemistry, Al-Hussein Bin Talal University, P.O. Box 20, Ma' an (Jordan)

    2009-04-06

    A new two-stage microwave-assisted digestion procedure using concentrated HNO{sub 3}, HCl, HF and H{sub 3}BO{sub 3} has been developed for the chemical analysis of major and trace elements in sulphide ore samples prior to inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis. In the first stage 0.2 g of the certified reference material (CRM) sample was digested with a combination of acids (HNO{sub 3}, HCl, and HF) in a closed Teflon vessel and heated in the microwave to 200 deg. C for 30 min. After cooling, H{sub 3}BO{sub 3} was added and the vessel was reheated to 170 deg. C for 15 min. The precision of the method was checked by comparing the results against six certified reference materials. The analytical results obtained were in good agreement with the certified values, in most cases the recoveries were in the range 95-105%. Based on at least 17 replicates of sample preparation and analysis, the precision of the method was found to be {<=}5%.

  19. Microwave-assisted total digestion of sulphide ores for multi-element analysis

    International Nuclear Information System (INIS)

    A new two-stage microwave-assisted digestion procedure using concentrated HNO3, HCl, HF and H3BO3 has been developed for the chemical analysis of major and trace elements in sulphide ore samples prior to inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis. In the first stage 0.2 g of the certified reference material (CRM) sample was digested with a combination of acids (HNO3, HCl, and HF) in a closed Teflon vessel and heated in the microwave to 200 deg. C for 30 min. After cooling, H3BO3 was added and the vessel was reheated to 170 deg. C for 15 min. The precision of the method was checked by comparing the results against six certified reference materials. The analytical results obtained were in good agreement with the certified values, in most cases the recoveries were in the range 95-105%. Based on at least 17 replicates of sample preparation and analysis, the precision of the method was found to be ≤5%.

  20. New optical paper sensor for in situ measurement of hydrogen sulphide in waters and atmospheres.

    Science.gov (United States)

    Pla-Tolós, J; Moliner-Martínez, Y; Verdú-Andrés, J; Casanova-Chafer, J; Molins-Legua, C; Campíns-Falcó, P

    2016-08-15

    A novel and low-cost colorimetric sensor for the determination of hydrogen sulphide in environmental samples has been developed. This sensor is based on the immobilization of the reagent N,N-Dimethyl-p-phenylenediamine and FeCl3 in paper support, in which the H2S is adsorbed in order to give rise to the formation of methylene blue as reaction product. The sensor has been applied to determine H2S in water and air samples. Two different sampling systems for H2S caption from the air have been assayed: active and passive sampling. The analytical properties of the different systems have been obtained and compared. The analytical signals, corresponding to the methylene blue, have been obtained measuring the absorbance by conventional reflectance diffuse or using different algorithms for quantifying color intensity. The results obtained with both measurement procedures were comparable, with a detection limit of 1.11 and 1.12mLm(-3) for air samples (active and passive), and 0.5mgL(-1) for water samples. The developed sensor provides good accuracy and precision (RSD<12%) and simplifies significantly the analytical measurements because it avoids the need of preparing derivatization reagents, sample handling and allows in situ measurements. The reaction product obtained is highly stable in this support and no provide any blank signal. Under the optimal conditions, the proposed method exhibit excellent visual sensitivity for the naked eye procedure, making the detection of H2S possible. PMID:27260438

  1. Discovery of the Eureka volcanogenic massive sulphide lens using downhole electromagnetics

    Science.gov (United States)

    Paggi, Jacob; Macklin, Daniel

    2016-05-01

    The Eureka volcanogenic massive sulphide (VMS) lens forms part of the Stockman Project in north-east Victoria. Eureka was discovered in early 2013, heralding the first new VMS mineralised zone to be discovered at the project since 1979. Key drivers to the detection of Eureka included the combination of downhole electromagnetics (EM) and a robust geological model. The lens is located 350 m to the north-east of the Currawong deposit, at a vertical depth of 360 m. Surface EM methods played a significant role in the discovery of the nearby Currawong and Wilga deposits during the late 1970s. Despite this, modern day airborne and fixed-loop transient EM (FLTEM) surveys failed to detect Eureka, most likely due to its depth, moderate conductance and loop-edge effects masking anomalies. The key component in discovering the lens was the interpretation of two subtle downhole transient electromagnetics (DHTEM) responses from 2012 exploration drillholes. These responses were further strengthened by structural and short wave infrared modelling, presenting a compelling multi-component drill target. The lens was discovered soon thereafter, with a discovery intercept of 22.65 m at 1.2% Cu, 0.7% Pb, 3.9% Zn, 43 g/t Ag and 1.3 g/t Au.

  2. Linking performance to microbiology in biofilters treating dimethyl sulphide in the presence and absence of methanol.

    Science.gov (United States)

    Hayes, Alexander C; Zhang, Yuefeng; Liss, Steven N; Allen, D Grant

    2010-01-01

    The performance and microbiology of two inorganic biofilters treating dimethyl sulphide (DMS) in the presence and absence of methanol was investigated. Addition of methanol was shown to result in an increase in DMS removal for methanol loadings below 90 g MeOH per cubic metre per hour with the optimal methanol loading around 10-15 g MeOH per cubic metre per hour for a DMS loading of 3.4 g DMS per cubic metre per hour, a fivefold increase in the DMS removal rate compared to the biofilter treating DMS alone. Microbial community analysis revealed that the addition of methanol led to a significant increase of up to an order of magnitude in the abundance of Hyphomicrobium spp. in the biofilter co-treating DMS and methanol compared to the biofilter treating DMS alone, whilst there was no significant difference in the abundance of Thiobacillus spp. between the two biofilters. Given the behaviour of the biofilter co-treating DMS and methanol, the magnitude of the increase in Hyphomicrobium spp. in the biofilter co-treating DMS and methanol and the ability of Hyphomicrobium spp. to use both methanol and DMS as growth substrates, it was concluded that Hyphomicrobium spp. were the microorganisms responsible for the bulk of the DMS degradation in the biofilter co-treating DMS and methanol.

  3. Laser Quenching and Ion Sulphidizing Complex Surface Treat Technology for Diesel Engine Cylinder

    Institute of Scientific and Technical Information of China (English)

    XIE Zhaoqian; ZENG Qingqiang; HUANG Huayuan; Cai Zhihai; ZHAO Yuqiang

    2012-01-01

    In order to solve the problem of wear-out-failure of diesel engine cylinder,the laser-quenching and low temperature ion sulfurizing complex surface treatment technology was operated on the surface of 42MnCr52 steel.And the tribological properties of the complex layer were investigated.The experimental results indicated that the complex layer was composed of soft surface sulphide layer and sub-surface laserquenching harden layer,and showed excellent friction-reduction and wear-resistance performance at high temperature.The synergistic effect of the complex layer resulted in 20% increase in hardness,10% reduction in friction coefficient and 50% reduction in wear weight loss,respectively,compared with those of the standard samples.The bench-test further demonstrated that this technology can improve the lubricating condition between cylinder and piston ring,and reduce both abnormity wear when the lubricating oil is deficiency at the time of start-up and sticking wear at high temperature during the operating period,and then prolong the service life of engine.

  4. High-throughput screening for thermoelectric sulphides by using crystal structure features as descriptors

    Science.gov (United States)

    Zhang, Ruizhi; Du, Baoli; Chen, Kan; Reece, Mike; Materials Research Insititute Team

    With the increasing computational power and reliable databases, high-throughput screening is playing a more and more important role in the search of new thermoelectric materials. Rather than the well established density functional theory (DFT) calculation based methods, we propose an alternative approach to screen for new TE materials: using crystal structural features as 'descriptors'. We show that a non-distorted transition metal sulphide polyhedral network can be a good descriptor for high power factor according to crystal filed theory. By using Cu/S containing compounds as an example, 1600+ Cu/S containing entries in the Inorganic Crystal Structure Database (ICSD) were screened, and of those 84 phases are identified as promising thermoelectric materials. The screening results are validated by both electronic structure calculations and experimental results from the literature. We also fabricated some new compounds to test our screening results. Another advantage of using crystal structure features as descriptors is that we can easily establish structural relationships between the identified phases. Based on this, two material design approaches are discussed: 1) High-pressure synthesis of metastable phase; 2) In-situ 2-phase composites with coherent interface. This work was supported by a Marie Curie International Incoming Fellowship of the European Community Human Potential Program.

  5. Probabilistic consequence assessment of hydrogen sulphide releases from a heavy water plant

    International Nuclear Information System (INIS)

    This report is concerned with the evaluation of the consequences to the public of an accidental release of hydrogen sulphide (H2S) to the atmosphere following a pipe or pressure envelope failure, or some other process upset, at a heavy water plant. It covers the first stage of a programme in which the nature of the problem was analyzed and recommendations made for the implementation of a computer model. The concepts of risk assessment and consequence assessment are discussed and a methodology proposed for combining the various elements of the problem into an overall consequence model. These elements are identified as the 'Initiating Events', 'Route to Receptor' and 'Receptor Response' and each is studied in detail in the report. Such phenomena as the blowdown of H2S from a rupture, the initial gas cloud behaviour, atmospheric dispersion and the toxicity of H2S and sulphur dioxide (SO2) are addressed. Critical factors are identified and modelling requirements specified, with special reference to the Bruce heavy water plant. Finally, an overall model is recommended for implementation at the next stage of the programme, together with detailed terms of reference for the remaining work

  6. The manganese effect on the magnetism and optical properties especially interband transitions of zinc sulphide

    Science.gov (United States)

    Aimouch, D. E.; Meskine, S.; Hayn, R.; Zaoui, A.; Boukortt, A.

    2016-10-01

    The electronic, magnetic and optical properties of Mn doped zinc sulphide (ZnS:Mn) were calculated with the FP-LAPW method by using the LSDA and LSDA+U approximations. The latter one is shown to be necessary to account for the strong electron correlation in the Mn 3d shell. With the increase of Mn2+ concentration, the band gap is decreased for the spin-up channel and increased for the spin-down channel. Furthermore, to calculate the correct exchange couplings d-d and sp-d of Mn-doped ZnS, we have applied the Hubbard U parameter on Mn-d states. The influence of this Hubbard U parameter on the optical, electronic and magnetic properties of ZnS:Mn is investigated. We found that U=6 eV gives good results for exchange couplings and optical properties close to the experimental ones. The magnetic coupling between neighboring Mn impurities in ZnS is found to be antiferromagnetic.

  7. Role of ore mineralogy in optimizing conditions for bioleaching low-grade complex sulphide ores

    Institute of Scientific and Technical Information of China (English)

    P. A. OLUBAMBI; S. NDLOVU; J. H. POTGIETER; J. O. BORODE

    2008-01-01

    The role that ore mineralogy plays in understanding and optimizing the conditions favouring the bioleaching of complex sulphide ore containing high amounts of siderite was studied using mixed cultures of mesophilic bacteria, with emphasis on zinc,lead and copper recoveries. The influencing parameters investigated include particle size, stirring speed, volume of inoculum, pulp density, and pH. The results show that the mixed mesophilic cultures can extract about two and a half times the amount of zinc than copper over an equivalent period of time. The highest zinc and copper recoveries of 89.2% and 36.4% respectively are obtained at particle size of 75 μm, stirring speed of 150 r/min, pulp density of 10% (w/v), 12% (v/v) inoculum concentration, and a pH of 1.6. Variations in elemental composition within different particle sizes resulting from the mineralogy of the ore account for the bioleaching behaviour at varying particle sizes. The dissolution at varying pulp density, volume of inoculum, solution pH and the low solution potential observed are also influenced by ore mineralogy.

  8. Mechanistic insight into the nucleation and growth of oleic acid capped lead sulphide quantum dots.

    Science.gov (United States)

    Shrestha, Aabhash; Spooner, Nigel A; Qiao, Shi Zhang; Dai, Sheng

    2016-05-18

    The quantum dots (QDs) of lead sulphide (PbS) are attractive near-infrared (NIR) active materials and have promising applications in a wide variety of applications. Till date many efforts have been made on optimizing its synthesis; however, current mechanistic understanding involving the nucleation and growth of these QDs has not reached the same level as that for other QDs. In this study, we present a detailed understanding on synthesis mechanism of PbS QDs so as to provide guidance for future QDs synthesis. The synthesis of PbS QDs is largely independent of classical nucleation process and the hot-injection of precursors may not be necessary for the successful synthesis of PbS QDs. The synthesis is basically a growth dominated process and is controlled by the Ostwald ripening of PbS QDs. In addition, reaction temperature and ligand are the key parameters for controlling QD growth. Temperature provides energy for overcoming activation barrier of QD growth while the ligands enhance QD growth via altering the environment for QD growth. Following the mechanism governing the synthesis of PbS QDs, we demonstrate that the size tuning of PbS QDs in ultra-small (synthesis. PMID:27156571

  9. Classification of Magmatic Sulphide Deposits in China and Mineralization of Small Intrusions

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Many important metal resources, such as Ni (Cu, Co), PGE, exist in magmatic sulfide deposits, are a hot spot in geological research. We divide the magmatic sulphide deposits in China into four types according to their tectonic setting, intruding mode, ore deposit mode, main metallogenic elements. The four types are as follows: (1) Small-intrusion deposits in paleo-continent; (2) Smallintrusion deposits in continental flood basalt; (3) Small-intrusion deposits in orogenic belt; and (4) The deposits associated with ophiolites. On the basis of the classification, we put forward that the main magmatic metallogenic type in China is small-intrusion metallogeny, and describe its characteristics from small intrusions related concept, three geologic settings, three volcanic-intrusive assemblages and metallogenic key factors. According to the experiences of prospecting at home and abroad, we point out that there is big potential in prospecting small-intrusion deposits, which need further study. At last, we indicate that small-intrusion metallogeny not only widely distributes in mafic-ultramafic intrusions,but also has an important economic value and scientific significance in intermediate-acid intrusions.

  10. Utilization of water-reducing admixtures in cemented paste backfill of sulphide-rich mill tailings.

    Science.gov (United States)

    Ercikdi, Bayram; Cihangir, Ferdi; Kesimal, Ayhan; Deveci, Haci; Alp, Ibrahim

    2010-07-15

    This study presents the effect of three different water-reducing admixtures (WRAs) on the rheological and mechanical properties of cemented paste backfill (CPB) samples. A 28-day strength of > or = 0.7 MPa and the maintenance of the stability (i.e. > or = 0.7 MPa) over 360 days of curing were desired as the design criteria. Ordinary Portland cement (OPC) and Portland composite cement (PCC) were used as binders at 5 wt.% dose. WRAs were initially tested to determine the dosage of a WRA for a required consistency of 7'' for CPB mixtures. A total of 192 CPB samples were then prepared using WRAs. The utilization of WRAs enhanced the flow characteristics of the CPB mixture and allowed to achieve the same consistency at a lower water-to-cement ratio. For OPC, the addition of WRAs appeared to improve the both short- and long-term performance of CPB samples. However, only polycarboxylate-based superplasticiser produced the desired 28-day strength of > or = 0.7 MPa when PCC was used as the binder. These findings suggest that WRAs can be suitably exploited for CPB of sulphide-rich tailings to improve the strength and stability in short and long terms allowing to reduce binder costs in a CPB plant. PMID:20382473

  11. Structural and optical characterization of barium sulphide thin films grown by solution growth technique

    International Nuclear Information System (INIS)

    Three thin films of barium sulphide were deposited on glass slides using solution growth technique. The bath compositions include barium chloride (BaCI/sub 2/) which was the source of Ba/sup 2+/ sodium thiosulphate (Na/sub 2/S/sub 2/O/sub 3/5H/sub 2/O), source of S/sup 2-) and EDTA served as a complexing agent. The structural compositions of these films were examined using the microscope (HUND WETZLAR H600) and camera (RICOH 35mm SLR, XR-X300) at magnification of x400. Fourier transform infrared (FTIR) spectroscopy and spectrophotometer were used to determine the optical properties like absorbance, transmittance, reflectance, refractive index, extinction coefficient and optical conductivity. The results of characterization show that these films have poor absorbance and reflectance. The transmittance range of the films from UV-NIR is 60-90%. The range of the refractive index is 1.3-1.6; extinction coefficient has range of 0.001-0.012 while optical conductivity has a range of 1.0 x10/sup 12/ s/sup -1/-2.5 * 10/sup 12/ s/sup -1/. (author)

  12. Controls of dimethyl sulphide in the Bay of Bengal during BOBMEX-Pilot cruise 1998

    Indian Academy of Sciences (India)

    D M Shenoy; M Dileep Kumar; V V S S Sarma

    2000-06-01

    The air-sea exchange is one of the main mechanisms maintaining the abundances of trace gases in the atmosphere. Some of these, such as carbon dioxide and dimethyl sulphide (DMS), will have a bearing on the atmospheric heat budget. While the former facilitates the trapping of radiation (greenhouse effect) the latter works in the opposite direction through reflectance of radiation back into space by sulphate aerosols that form from oxidation of DMS in atmosphere. Here we report on the first measurements made on DMS in the Bay of Bengal and the factors regulating its abundance in seawater. Phytoplankton alone does not seem to control the extent of DMS concentrations. We find that changes in salinity could effectively regulate the extent of DMSP production by marine phytoplankton. In addition, we provide the first ever evidence to the occurrence of DMS precursor, DMSP, in marine aerosols collected in the boundary layer. This suggests that the marine aerosol transport of DMSP will supplement DMS gaseous evasion in maintaining the atmospheric non-sea salt sulphur budget.

  13. Atomic absorption determination, in metal sulphide concentrates, of the elements that form gaseous hydrides

    International Nuclear Information System (INIS)

    An account is given of the investigational work on the determination of trace amounts of arsenic, antimony, bismuth, germanium, selenium, and tellurium by the technique using hydride generation and atomic-absorption spectrophotometry. The gaseous hydride is generated by reduction with sodium borohydride, and is subsequently swept by a flow of nitrogen into an air-entrained hydrogen-nitrogen flame. The generation equipment used is simple and inexpensive, and can be readily assembled in most laboratories. The optimum parameters were determined for each element. The effects of 31 probable interfering elements were investigated, and it was found that, although the majority did not interfere, severe interference was encountered when copper, nickel, and the noble metals were present. Methods for the elimination of copper and nickel were developed to allow the determination of arsenic, antimony, bismuth, selenium, and tellurium at the lower parts-per-million level in metal sulphide concentrates with an acceptable accuracy and precision. The determination of microgram amounts of germanium was found to be unsatisfactory

  14. Cobalt and precious metals in sulphides of peridotite xenoliths and inferences concerning their distribution according to geodynamic environment: A case study from the Scottish lithospheric mantle

    Science.gov (United States)

    Hughes, Hannah S. R.; McDonald, Iain; Faithfull, John W.; Upton, Brian G. J.; Loocke, Matthew

    2016-01-01

    Abundances of precious metals and cobalt in the lithospheric mantle are typically obtained by bulk geochemical analyses of mantle xenoliths. These elements are strongly chalcophile and the mineralogy, texture and trace element composition of sulphide phases in such samples must be considered. In this study we assess the mineralogy, textures and trace element compositions of sulphides in spinel lherzolites from four Scottish lithospheric terranes, which provide an ideal testing ground to examine the variability of sulphides and their precious metal endowments according to terrane age and geodynamic environment. Specifically we test differences in sulphide composition from Archaean-Palaeoproterozoic cratonic sub-continental lithospheric mantle (SCLM) in northern terranes vs. Palaeozoic lithospheric mantle in southern terranes, as divided by the Great Glen Fault (GGF). Cobalt is consistently elevated in sulphides from Palaeozoic terranes (south of the GGF) with Co concentrations > 2.9 wt.% and Co/Ni ratios > 0.048 (chondrite). In contrast, sulphides from Archaean cratonic terranes (north of the GGF) have low abundances of Co (< 3600 ppm) and low Co/Ni ratios (< 0.030). The causes for Co enrichment remain unclear, but we highlight that globally significant Co mineralisation is associated with ophiolites (e.g., Bou Azzer, Morocco and Outokumpu, Finland) or in oceanic peridotite-floored settings at slow-spreading ridges. Thus we suggest an oceanic affinity for the Co enrichment in the southern terranes of Scotland, likely directly related to the subduction of Co-enriched oceanic crust during the Caledonian Orogeny. Further, we identify a distinction between Pt/Pd ratio across the GGF, such that sulphides in the cratonic SCLM have Pt/Pd ≥ chondrite whilst Palaeozoic sulphides have Pt/Pd < chondrite. We observe that Pt-rich sulphides with discrete Pt-minerals (e.g., PtS) are associated with carbonate and phosphates in two xenolith suites north of the GGF. This three

  15. Market for nickel-cadmium batteries

    Science.gov (United States)

    Putois, F.

    Besides the lead/acid battery market, which has seen a tremendous development linked with the car industry, the alkaline rechargeable battery market has also been expanded for more than twenty years, especially in the field of portable applications with nickel-cadmium batteries. Today, nickel-cadmium batteries have to face newcomers on the market, such as nickel-metal hydride, which is another alkaline couple, and rechargeable lithium batteries; these new battery systems have better performances in some areas. This work illustrates the status of the market for nickel-cadmium batteries and their applications. Also, for two major applications—the cordless tool and the electric vehicles—the competitive situation of nickel-cadmium batteries; facing new systems such as nickel-metal hydride and lithium ion cells are discussed.

  16. RISK ASSESSMENT AND MANAGEMENT OF ENVIRONMENTAL CADMIUM

    Science.gov (United States)

    Cadmium consumed in foods grown on soils contaminated by industrial Cd+Zn discharge has caused renal tubular dysfunction in exposed humans in discrete situations. However, lack of understanding about environmental Cd has caused wide concern that generalpopulations may...

  17. Some Aspects of Sealed Nickel Cadmium Cells

    Directory of Open Access Journals (Sweden)

    P. K. Saha

    1967-11-01

    Full Text Available Sealed Nickel Cadmium Cell system is termed till today as the most reliable power pack for electronic apparatus specially in low temperature use. This paper brings out the development and production of sealed nickel cadmium cells of pocket plate construction. The author who has gained experience in production of Ni-Cd cells in East Germany discusses also the major problems faced by the battery manufactures of to-day.

  18. Cadmium zinc telluride spectral modeling

    International Nuclear Information System (INIS)

    Cadmium zinc telluride (CZT) detectors are the highest resolution room temperature gamma-ray detectors available for isotopic analysis. As with germanium detectors, accurate isotopic analysis using spectra requires peak deconvolution. The CZT peak shapes are asymmetric, with a long low energy tail. The asymmetry is a result of the physics of the electron/hole transport in the semiconductor. An accurate model of the physics of the electron/hole transport through an electric field will allow the parameterization of the peak shapes as a function of energy. In turn this leads to the ability to perform accurate spectral deconvolution and therefore accurate isotopic analysis. The model and the peak-shape parameterization as a function of energy will be presented

  19. Cadmium leaching from thermal treated and gamma irradiated Mexican aluminosilicates

    Energy Technology Data Exchange (ETDEWEB)

    Davila-Rangel, J.I. [Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, Mexico 11801, D.F. (Mexico); Unidad Academica Centro Regional de Estudios Nucleares, Universidad Autonoma de Zacatecas Cipres 10, Frac. La Penuela, Zacatecas, Zacatecas 98068 (Mexico); Facultad de Ciencias, Universidad Autonoma del Estado de Mexico, Instituto Literario No. 100 Col. Centro C.P. 50000, Toluca, Edo. de Mexico (Mexico); Solache-Rios, M. [Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, Mexico 11801, D.F. (Mexico)], E-mail: msr@nuclear.inin.mx

    2008-10-15

    Thermal and radiation effects on the leaching of cadmium from two cadmium exchanged zeolitic tuffs and one clay were determined. The cadmium exchanged aluminosilicates were heated at different temperatures (500, 700, 900 and 1100 {sup o}C), and the materials were then treated with NaCl (1 M and 5 M) and HNO{sub 3} (0.001 M and 1 M) solutions to determine the leaching behaviour of cadmium from the materials. The stability of cadmium in the materials increased as the heating temperature was increased. Cadmium leaching from gamma irradiated and heated materials at 1100 {sup o}C was higher than leaching from non-irradiated samples.

  20. Cadmium leaching from thermal treated and gamma irradiated Mexican aluminosilicates

    International Nuclear Information System (INIS)

    Thermal and radiation effects on the leaching of cadmium from two cadmium exchanged zeolitic tuffs and one clay were determined. The cadmium exchanged aluminosilicates were heated at different temperatures (500, 700, 900 and 1100 oC), and the materials were then treated with NaCl (1 M and 5 M) and HNO3 (0.001 M and 1 M) solutions to determine the leaching behaviour of cadmium from the materials. The stability of cadmium in the materials increased as the heating temperature was increased. Cadmium leaching from gamma irradiated and heated materials at 1100 oC was higher than leaching from non-irradiated samples

  1. Enhanced performance of hybrid solar cells using longer arms of quantum cadmium selenide tetrapods

    KAUST Repository

    Lee, Kyu-Sung

    2011-12-01

    We demonstrate that enhanced device performance of hybrid solar cells based on tetrapod (TP)-shaped cadmium selenide (CdSe) nanoparticles and conjugated polymer of poly (3-hexylthiophene) (P3HT) can be obtained by using longer armed tetrapods which aids in better spatial connectivity, thus decreasing charge hopping events which lead to better charge transport. Longer tetrapods with 10 nm arm length lead to improved power conversion efficiency of 1.12% compared to 0.80% of device having 5 nm short-armed tetrapods:P3HT photoactive blends.

  2. MSA-capped gold nanoparticle-supported alumina for the determination of Pb and Cd in various environmental water samples

    Science.gov (United States)

    Kiran, K.

    2014-11-01

    2-Mercaptosuccinic acid (MSA)-capped gold nanoparticles (GNPs) were used to determine the level of concentration of lead and cadmium metals in various environmental samples. Alumina-coated MSA-capped GNPs easily remove lead and cadmium present in various samples. The absorbance spectrum was obtained at 547 nm. Effects of pH, reagent concentration, interferences, were studied. This method is simple, selective and successfully applied for the determination of lead and cadmium species in various water samples collected in and around four industries.

  3. Ordered structures based on self-organized Au and CdSe nanoparticles

    International Nuclear Information System (INIS)

    Methods for obtaining cadmium selenide and gold nanoparticles have been developed. The sizes of the nanoparticles are determined and the morphology, structure, and chemical composition of these nanoparticles and their ensembles are studied by a complex of structural methods: electron diffraction, X-ray diffraction, energy-dispersive X-ray analysis, high-resolution transmission electron microscopy, and small-angle X-ray scattering. Gold nanoparticles are mainly spherical and have an average size of 10 nm. They are single-phase and have an fcc crystal structure. Samples of synthesized CdSe nanoparticles contain monodisperse spherical particles 12 nm in size with a wurtzite structure. The deposition of nanoparticles on a carbon substrate is accompanied by their self-organization into a closely packed two-dimensional structure with a pronounced texture in which all nanoparticles are oriented in the [001] direction perpendicularly to the carbon substrate plane.

  4. Reviews of the environmental effects of pollutants: IV. Cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Hammons, A.S.; Huff, J.E.; Braunstein, H.M.; Drury, J.S.; Shriner, C.R.; Lewis, E.B.; Whitfield, B.L.; Towill, L.E.

    1978-06-01

    This report is a comprehensive, multidisciplinary review of the health and environmental effects of cadmium and specific cadmium derivatives. More than 500 references are cited. The cadmium body burden in animals and humans results mainly from the diet. In the United States, the normal intake of cadmium for adult humans is estimated at about 50 ..mu..g per day. Tobacco smoke is a significant additional source of cadmium exposure. The kidneys and liver together contain about 50% of the total cadmium body burden. Acute cadmium poisoning is primarily an occupational problem, generally from inhalation of cadmium fumes or dusts. In the general population, incidents of acute poisoning by inhaled or ingested cadmium or its compounds are relatively rare. The kidney is the primary target organ for toxicity from prolonged low-level exposure to cadmium. No causal relationship has been established between cadmium exposure and human cancer, although a possible link between cadmium and prostate cancer has been indicated. Cadmium has been shown to be teratogenic in rats, hamsters, and mice, but no such effects have been proven in humans. Cadmium has been reported to increase the frequency of chromosomal aberrations in cultured Chinese hamster ovary cells and in human peripheral leukocytes. The major concern about environmental cadmium is the potential effects on the general population. There is no substantial evidence of hazard from current levels of cadmium in air, water, or food. However, because cadmium is a cumulative poison and because present intake provides a relatively small safety margin, there are adequate reasons for concern over possible future increases in background levels.

  5. Reviews of the environmental effects of pollutants: IV. Cadmium

    International Nuclear Information System (INIS)

    This report is a comprehensive, multidisciplinary review of the health and environmental effects of cadmium and specific cadmium derivatives. More than 500 references are cited. The cadmium body burden in animals and humans results mainly from the diet. In the United States, the normal intake of cadmium for adult humans is estimated at about 50 μg per day. Tobacco smoke is a significant additional source of cadmium exposure. The kidneys and liver together contain about 50% of the total cadmium body burden. Acute cadmium poisoning is primarily an occupational problem, generally from inhalation of cadmium fumes or dusts. In the general population, incidents of acute poisoning by inhaled or ingested cadmium or its compounds are relatively rare. The kidney is the primary target organ for toxicity from prolonged low-level exposure to cadmium. No causal relationship has been established between cadmium exposure and human cancer, although a possible link between cadmium and prostate cancer has been indicated. Cadmium has been shown to be teratogenic in rats, hamsters, and mice, but no such effects have been proven in humans. Cadmium has been reported to increase the frequency of chromosomal aberrations in cultured Chinese hamster ovary cells and in human peripheral leukocytes. The major concern about environmental cadmium is the potential effects on the general population. There is no substantial evidence of hazard from current levels of cadmium in air, water, or food. However, because cadmium is a cumulative poison and because present intake provides a relatively small safety margin, there are adequate reasons for concern over possible future increases in background levels

  6. Sulphide and sulphosalt mineralogy and paragenesis from the Sierra Almagrera veins, Betic Cordillera (SE Spain

    Directory of Open Access Journals (Sweden)

    Martínez Frías, J.

    1991-12-01

    Full Text Available The Sierra Almagrera vein-type mineralization contains base metal sulphides and Pb-Sb- Cu-Ag sulphosalts. The sulphides possess significant proportions of Ag, Sb (galena, Fe (sphalerite and Sb, Zn (chalcopyrite. Ore microscopy and electron microprobe have revealed a mineralogical and textural variation and confirmed the presence of bournonite, boulangerite and anomalous tetrahedrite. The average sulphosalt formulas are bournonite Cu0.98 Pb0. 96 Sb0.98 S3.04, boulangerite Pb4.8Sb3.8S11.34 and anomalous tetrahedrite Ag0.6Cu9.7 Zn3.6 Fe0. 44 Sb3.47 S13- The sequence of mineral deposition indicates the existance of four mineralizing stages and one supergene alteration: 1 Fe-(As; 2 Zn-Cu-Fe; 3 Pb-Sb-Cu-Ag; 4 Cu-Zn-Fe, and 5 carbonates, sulphates and supergene oxides. In broad terms, it is possible to establish the following conclusions: a there exist a mineralogical and textural variation with depth, the Pb-Sb-Cu-Ag stage reaching the maximum development; b a temperature decrease during the formation of sph. 1, linked to the progressive increase in Fe-content of the sphalerite has been detected; c the compositional homogeneity of the bournonite (and the fair lack of As in the tetrahedrite could indicate the existance of a possible tendancy to individually crystallise the Sb and As sulphosalts, according to the trend Bi → Sb → As.La mineralización filoniana de Sierra Almagrera presenta una interesante paragénesis caracterizada por la presencia de sulfuros de metales base y sulfosales de Pb-Sb-Cu-Ag. Se ha identificado una secuencialidad textural y química de las distintas fases minerales, según la cual los sulfuros poseen variaciones significativas de las proporciones de Ag, Sb (galena, Fe (esfalerita, y Sb, Zn (calcopirita, yen la que las sulfosales son fundamentalmente sulfoantimoniuros (bournonita: Cu0.98 Pb0. 96 Sb0.98 S3.04, boulangerita Pb4.8Sb3.8S11.34 y tetraedrita anómala Ag0.6Cu9.7 Zn3.6 Fe0. 44 Sb3.47 S13-. La secuencia de

  7. Cadmium removal by Lemna minor and Spirodela polyrhiza.

    Science.gov (United States)

    Chaudhuri, Devaleena; Majumder, Arunabha; Misra, Amal K; Bandyopadhyay, Kaushik

    2014-01-01

    The present study investigates the ability of two genus of duckweed (Lemna minor and Spirodela polyrhiza) to phytoremediate cadmium from aqueous solution. Duckweed was exposed to six different cadmium concentrations, such as, 0.5,1.0,1.5, 2.0, 2.5, and 3.0 mg/L and the experiment was continued for 22 days. Water samples were collected periodically for estimation of residual cadmium content in aqueous solution. At the end of treatment period plant samples were collected and accumulated cadmium content was measured. Cadmium toxicity was observed through relative growth factor and changes in chlorophyll content Experimental results showed that Lemna minor and Spirodela polyrhiza were capable of removing 42-78% and 52-75% cadmium from media depending upon initial cadmium concentrations. Cadmium was removed following pseudo second order kinetic model Maximum cadmium accumulation in Lemna minor was 4734.56 mg/kg at 2 mg/L initial cadmium concentration and 7711.00 mg/kg in Spirodela polyrhiza at 3 mg/L initial cadmium concentration at the end of treatment period. Conversely in both cases maximum bioconcentration factor obtained at lowest initial cadmium concentrations, i.e., 0.5 mg/L, were 3295.61 and 4752.00 for Lemna minor and Spirodela polyrhiza respectively. The present study revealed that both Lemna minor and Spirodela polyrhiza was potential cadmium accumulator. PMID:24933906

  8. Hydrogen sulphide improves adaptation of Zea mays seedlings to iron deficiency.

    Science.gov (United States)

    Chen, Juan; Wu, Fei-Hua; Shang, Yu-Ting; Wang, Wen-Hua; Hu, Wen-Jun; Simon, Martin; Liu, Xiang; Shangguan, Zhou-Ping; Zheng, Hai-Lei

    2015-11-01

    Hydrogen sulphide (H2S) is emerging as a potential molecule involved in physiological regulation in plants. However, whether H2S regulates iron-shortage responses in plants is largely unknown. Here, the role of H2S in modulating iron availability in maize (Zea mays L. cv Canner) seedlings grown in iron-deficient culture solution is reported. The main results are as follows: Firstly, NaHS, a donor of H2S, completely prevented leaf interveinal chlorosis in maize seedlings grown in iron-deficient culture solution. Secondly, electron micrographs of mesophyll cells from iron-deficient maize seedlings revealed plastids with few photosynthetic lamellae and rudimentary grana. On the contrary, mesophyll chloroplasts appeared completely developed in H2S-treated maize seedlings. Thirdly, H2S treatment increased iron accumulation in maize seedlings by changing the expression levels of iron homeostasis- and sulphur metabolism-related genes. Fourthly, phytosiderophore (PS) accumulation and secretion were enhanced by H2S treatment in seedlings grown in iron-deficient solution. Indeed, the gene expression of ferric-phytosiderophore transporter (ZmYS1) was specifically induced by iron deficiency in maize leaves and roots, whereas their abundance was decreased by NaHS treatment. Lastly, H2S significantly enhanced photosynthesis through promoting the protein expression of ribulose-1,5-bisphosphate carboxylase large subunit (RuBISCO LSU) and phosphoenolpyruvate carboxylase (PEPC) and the expression of genes encoding RuBISCO large subunit (RBCL), small subunit (RBCS), D1 protein (psbA), and PEPC in maize seedlings grown in iron-deficient solution. These results indicate that H2S is closely related to iron uptake, transport, and accumulation, and consequently increases chlorophyll biosynthesis, chloroplast development, and photosynthesis in plants.

  9. Microbial ecology of Rum Jungle, III. Leaching behaviour of sulphidic waste material under controlled conditions

    International Nuclear Information System (INIS)

    The discharge, into river systems, of acid and heavy metals generated by leaching of sulphidic waste materials at the abandoned opencut uranium mine at Rum Jungle, Northern Territory, is causing continuing pollution of the surrounding environment. The maximum effects of acid and microorganisms on samples from the overburden dump material, under defined and controlled environmental conditions, were assessed using reactor systems. These samples came from the overburden dump resulting from the mining of White's orebody. Similarly, the stability of tailings material under conditions of flooding and increasing acidity was determined. At ph 2.5, metals in White's dump material were solubilised by acid attack only, whereas at pH 3.5, bacterial activity (principally that of Thiobacillus ferrooxidans) generated acidity and contributed significantly to metal release. Under microaerophilic conditions Thiobacillus ferrooxidans continued to effect metal release from the ore, but did not produce further acidity. If White's overburden is returned to the acidic, flooded opencuts, complete solubilisation of the material will occur. The exclusion of oxygen from the dump will not necessarily stop bacterially catalysed leaching processes. Under highly aerated and agitated flooded conditions the tailings material was not active, except for copper release of about 2 g kg-1 ore at pH 4.0. The only deleterious element released by increasing acidity was copper, which was 100 per cent solubilised at pH 2.5. Uranium was always lss than 3 μg kg-1 ore, and lead was detected only at pH 2.5. Indigenous leaching bacteria did not develop

  10. Leaching of a gold bearing partially roasted sulphide. Laboratory scale studies

    Directory of Open Access Journals (Sweden)

    Almeida M.F.

    2001-01-01

    Full Text Available This research aimed at defining a route for recovering precious metals from a very heterogeneous gold bearing sulphide and arsenide concentrate that was partially roasted and dumped by the 1960s when Santo António mine closed. Gold occurs in this concentrate as free particles in the range of 10-100 mum, most of them still enclosed in the pyrite and arsenopyrite matrix. Its content varies from 20 to 150 g of Au/ton, being higher at the dump upper levels and in the finer concentrate fractions. Preliminary tests demonstrated the refractoriness of this product, since the leaching with conventional cyanide solutions and with other leaching solutions gave very low recoveries. However, high concentrated cyanide solutions recover more than 60% of Au, although with high NaCN and lime consumptions and poor settling characteristics. Iron was shown to be highly dissolved in these solutions. Some prior treatments clearly favoured the cyanidation process, in particular a roasting step. Thus, a large number of roasting experiments was carried out to define the most favourable conditions for recovering gold. However, no clear relationship between roasting conditions and gold dissolution was found due to the heterogeneity of the product and high variance of gold experimental recoveries. These recoveries were calculated considering gold contained in both the leaching residues and leachates, and uncertainties of these results are relatively high. Roasting the product at 450-700 °C for 1 h guarantees a high probability to dissolve at least 74% Au in a highly concentrated NaCN solution stirred for 24 h. The 600-700 °C roasting range is clearly preferable for consuming less cyanide and lime. Pre-washing the roasted product seems not to reduce the cyanide consumption. Regarding the silver recovery, the NaCN and lime consumption are higher while using the products roasted at the lowest tested temperatures. Products roasted at higher temperatures have better settling

  11. Well materials durability in case of carbon dioxide and hydrogen sulphide geological sequestration

    International Nuclear Information System (INIS)

    The geological sequestration of carbon dioxide (CO2) and hydrogen sulphide (H2S) is a promising solution for the long-term storage of these undesirable gases. It consists in injecting them via wells into deep geological reservoirs. The steel and cement employed in the well casing can be altered and provide pathways for leakage with subsequent human and environmental consequences. The materials ageing was investigated by laboratory experiments in geologically relevant P-T conditions. A new experimental and analysis procedure was designed for this purpose. A numerical approach was also done. The cement and steel were altered in various fluid phases at 500 bar-120 C and 500 bar-200 C: a brine, a brine saturated with H2S-CO2, a mixture of brine saturated with H2S-CO2 and of supercritical H2S-CO2 phase, a dry supercritical H2S-CO2 phase without liquid water. In all cases, two distinct reactions are observed: the cement carbonation by the CO2 and the steel sulfidation by the H2S. The carbonation and sulfidation are respectively maximal and minimal when they occur within the dry supercritical phase without liquid water. The textural and porosity properties of the cement are weakly affected by all the treatments at 120 C. The porosity even decreases in presence of H2S-CO2. But these properties are affected at 200 C when liquid water is present in the system. At this temperature, the initial properties are only preserved or improved by the treatments within the dry supercritical phase. The steel is corroded in all cases and thus is the vulnerable material of the wells. (author)

  12. Precipitation of arsenic sulphide from acidic water in a fixed-film bioreactor.

    Science.gov (United States)

    Battaglia-Brunet, Fabienne; Crouzet, Catherine; Burnol, André; Coulon, Stéphanie; Morin, Dominique; Joulian, Catherine

    2012-08-01

    Arsenic (As) is a toxic element frequently present in acid mine waters and effluents. Precipitation of trivalent arsenic sulphide in sulphate-reducing conditions at low pH has been studied with the aim of removing this hazardous element in a waste product with high As content. To achieve this, a 400m L fixed-film column bioreactor was fed continuously with a synthetic solution containing 100mg L(-1) As(V), glycerol and/or hydrogen, at pH values between 2.7 and 5. The highest global As removal rate obtained during these experiments was close to 2.5mg L(-1)h(-1). A switch from glycerol to hydrogen when the biofilm was mature induced an abrupt increase in the sulphate-reducing activity, resulting in a dramatic mobilisation of arsenic due to the formation of soluble thioarsenic complexes. A new analytical method, based on ionic chromatography, was used to evaluate the proportion of As present as thioarsenic complexes in the bioreactor. Profiles of pH, total As and sulphate concentrations suggest that As removal efficiency was linked to solubility of orpiment (As(2)S(3)) depending on pH conditions. Molecular fingerprints revealed fairly homogeneous bacterial colonisation throughout the reactor. The bacterial community was diverse and included fermenting bacteria and Desulfosporosinus-like sulphate-reducing bacteria. arrA genes, involved in dissimilatory reduction of As(V), were found and the retrieved sequences suggested that As(V) was reduced by a Desulfosporosinus-like organism. This study was the first to show that As can be removed by bioprecipitation of orpiment from acidic solution containing up to 100mg L(-1) As(V) in a bioreactor.

  13. Cadmium exposure induces hematuria in Korean adults

    International Nuclear Information System (INIS)

    Introduction: Toxic heavy metals have adverse effects on human health. However, the risk of hematuria caused by heavy metal exposure has not been evaluated. Methods: Data from 4701 Korean adults were obtained in the Korean National Health and Nutritional Examination Survey (2008–2010). Blood levels of the toxic heavy metals cadmium, lead, and mercury were measured. Hematuria was defined as a result of ≥+1 on a urine dipstick test. The odds ratios (ORs) for hematuria were measured according to the blood heavy metal levels after adjusting for multiple variables. Results: Individuals with blood cadmium levels in the 3rd and 4th quartiles had a greater OR for hematuria than those in the 1st quartile group: 3rd quartile, 1.35 (1.019–1.777; P=0.037); 4th quartile, 1.52 (1.140–2.017; P=0.004). When blood cadmium was considered as a log-transformed continuous variable, the correlation between blood cadmium and hematuria was significant: OR, 1.97 (1.224–3.160; Ptrend=0.005). In contrast, no significant correlations between hematuria and blood lead or mercury were found in the multivariate analyses. Discussion: The present study shows that high cadmium exposure is associated with a risk of hematuria. -- Highlights: • A high level of blood cadmium is associated with a high risk of hematuria. • This correlation is independent of several confounding factors. • Blood levels of lead and mercury are not associated with risk of hematuria. • This is the first study on the correlation between cadmium exposure and hematuria risk

  14. Cadmium exposure induces hematuria in Korean adults

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seung Seok [Department of Internal Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Kim, Myounghee, E-mail: dkkim73@gmail.com [Department of Dental Hygiene, College of Health Science, Eulji University, Gyeonggi-do 461-713 (Korea, Republic of); Lee, Su Mi [Department of Internal Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Lee, Jung Pyo [Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul 156-707 (Korea, Republic of); Kim, Sejoong [Department of Internal Medicine, Seoul National University Bundang Hospital, Gyeonggi-do 463-707 (Korea, Republic of); Joo, Kwon Wook [Department of Internal Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Lim, Chun Soo [Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul 156-707 (Korea, Republic of); Kim, Yon Su; Kim, Dong Ki [Department of Internal Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of)

    2013-07-15

    Introduction: Toxic heavy metals have adverse effects on human health. However, the risk of hematuria caused by heavy metal exposure has not been evaluated. Methods: Data from 4701 Korean adults were obtained in the Korean National Health and Nutritional Examination Survey (2008–2010). Blood levels of the toxic heavy metals cadmium, lead, and mercury were measured. Hematuria was defined as a result of ≥+1 on a urine dipstick test. The odds ratios (ORs) for hematuria were measured according to the blood heavy metal levels after adjusting for multiple variables. Results: Individuals with blood cadmium levels in the 3rd and 4th quartiles had a greater OR for hematuria than those in the 1st quartile group: 3rd quartile, 1.35 (1.019–1.777; P=0.037); 4th quartile, 1.52 (1.140–2.017; P=0.004). When blood cadmium was considered as a log-transformed continuous variable, the correlation between blood cadmium and hematuria was significant: OR, 1.97 (1.224–3.160; P{sub trend}=0.005). In contrast, no significant correlations between hematuria and blood lead or mercury were found in the multivariate analyses. Discussion: The present study shows that high cadmium exposure is associated with a risk of hematuria. -- Highlights: • A high level of blood cadmium is associated with a high risk of hematuria. • This correlation is independent of several confounding factors. • Blood levels of lead and mercury are not associated with risk of hematuria. • This is the first study on the correlation between cadmium exposure and hematuria risk.

  15. Hazards to wildlife from soil-borne cadmium reconsidered

    Science.gov (United States)

    Beyer, W.N.

    2000-01-01

    Cadmium is a toxic element that should be included in environmental risk assessments of contaminated soils. This paper argues, however, that hazards to wildlife from cadmium have often been overstated. The literature contains only meager evidence that wild animals have been seriously harmed by cadmium, even at severely contaminated sites. Although some researchers have reported that wildlife have accumulated concentrations of cadmium in their kidneys that were above suggested injury thresholds, the thresholds may be disputed, since they were well below the World Health Organization criterion of 200 mg/kg (wet weight) of cadmium in the renal cortex for protecting human health. Recent risk assessments have concluded that soil cadmium concentrations less than 1 mg/kg are toxic to soil organisms and wildlife, which implies that background concentrations of cadmium naturally found in soils are hazardous. An examination of the databases used to support these assessments suggested that the toxicity of cadmium has been exaggerated.

  16. Microbial corrosion and cracking in steel. Fundamental studies on the electrochemical behaviour of carbon steel exposed in sulphide and sulphate-reducing environments

    Energy Technology Data Exchange (ETDEWEB)

    Rischel Hilbert, Lisbeth

    1998-08-01

    The aim of the report is to give a fundamental understanding of the response of different electrochemical techniques on carbon steel in a sulphide environment as well as in a biologically active sulphate-reducing environment (SRB). This will form the basis for further studies and for recommendations in regards to electrochemical monitoring of MIC. The work presented here and further studies are also planned to lead to a Ph.D. thesis on `MIC monitoring based on mechanisms on corrosion`. The results of laboratory experiments conducted in the period 1995 to 1997 are summarised. Conclusions will be based on results from the entire 3 year period, but only selected experimental data primarily from the latest experiments will be presented in detail here. Microbial corrosion of carbon steel under influence of sulphate-reducing bacteria (SRB) is characterised by the formation of both biofilm and corrosion products (ferrous sulphides) on the metal surface. Experiments have been conducted on carbon steel exposed in near neutral (pH 6 to 8.5) saline hydrogen sulphide environment (0 to 100 mg/l total dissolved sulphide) for a period of 14 days. Furthermore coupons have been exposed in a bioreactor for a period of up to 120 days in sulphide-producing environment controlled by biological activity of (SRB). (au)

  17. On the effect of thallium additions on cadmium amalgam potentials

    International Nuclear Information System (INIS)

    A study has been made of the influence of additives of thallium on potentials of cadmium amalgams with thallium contents of 10, 20, 30, and 40 at.% at 20, 40, 60, and 80 deg C. Additives of thallium have been found to shift the potential of cadmium amalgams towards the range of negative values which indicates an increase in the activity of cadmium. A possibility of calculation of the potential shift for heterogeneous cadmium amalgams on introducing thallium has been shown

  18. Influence of boat material on the structure, stoichiometry and optical properties of gallium sulphide films prepared by thermal evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Pritty [National Centre for Compositional Characterization of Materials, Bhabha Atomic Research Centre, ECIL Post, Hyderabad 500062 (India); Kumar, Sanjiv, E-mail: sanjucccm@rediffmail.com [National Centre for Compositional Characterization of Materials, Bhabha Atomic Research Centre, ECIL Post, Hyderabad 500062 (India); Sahoo, N.K. [Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2015-01-15

    The paper describes the deposition of thin films of gallium sulphide on soda-lime glass substrates by thermal evaporation of chemically synthesized powders consisting of gallium sulphide and gallium oxyhydroxide from a Mo or Ta boat and the evolution of their compositional, structural and optical properties on vacuum annealing. The films deposited from Mo or Ta boats possessed distinctly different properties. The Mo-boat evaporated pristine films were amorphous, transparent (α ∼ 10{sup 3} cm{sup −1}) in visible region and had a direct band gap of about 3.2 eV. Vacuum annealing at 723 K brought about their crystallization predominantly into cubic γ-Ga{sub 2}S{sub 3} and a blue shift by about 0.2 eV. The Ta-boat evaporated pristine films were also amorphous but were absorbing (α ∼ 10{sup 4} cm{sup −1}) and had a direct band gap of about 2.1 eV. These crystallized into hexagonal GaS and experienced a blue shift by more than 1.0 eV on vacuum annealing at 723 K. The dissimilar properties of the two kinds of films arose mainly from their different atomic compositions. The Mo-boat evaporated pristine films contained Ga and S in ∼1:1 atomic proportions while those prepared using Ta-boat were Ga rich which impaired their transmission characteristics. The former composition favoured the stabilization of S rich gallium sulphide (Ga{sub 2}S{sub 3}) phase while the latter stabilised S deficient species, GaS. Besides inducing crystallization, vacuum annealing at 723 K also caused the diffusion of Ga in excess of atomic composition of the phase formed, into soda-lime glass which improved the optical transmission of the films. Gallium oxyhydroxide, an inevitable co-product of the chemical synthetic process, in the evaporant introduced oxygen and hydrogen impurities in the films which do not seem to significantly influence their optical properties. - Highlights: • Gallium sulphide films are prepared by thermal evaporation from a Mo or Ta boat. • Mo

  19. Cadmium (II) pyrrolidine dithiocarbamate complex as single source precursor for the preparation of CdS nanocrystals by microwave irradiation and conventional heating process

    Science.gov (United States)

    Marx Nirmal, R.; Pandian, K.; Sivakumar, K.

    2011-01-01

    The complex of cadmium with pyrrolidine dithiocarbamate Cd(pdtc)2 has been used as single source precursor for the synthesis of CdS nanoparticles. The formation of CdS nanostructures was achieved by thermal decomposition of the complex under microwave irradiation and conventional heating in presence of hexadecylamine. The CdS nanoparticles with disordered close-packed structure were obtained under microwave irradiation, whereas wurtzite hexagonal phase CdS nanorods were obtained by conventional heating method (up to 150 °C). Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and high resolution transmission electron microscopy (HRTEM) studies also were carried out to study the structure and morphology of nanoparticles. The optical property of the CdS nanoparticles was studied by UV-visible and fluorescence emission spectral studies. Fluorescence measurements on the CdS nanoparticles show a strong emission spectrum with two sub bands that are attributed to band-edge and surface-defect emissions. The reduction of a suitable cadmium metal complex is considered to be one of the single pot methods to generate CdS semiconductor nanoparticles with different shapes and high yield.

  20. Recycling of Spent Nickel-Cadmium Batteries

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A technique for recycling spent nickel-cadmium batteries, which makes separation of cadmium and nickel possible, is developed by laboratory-scale experiments. NH3-H2CO3 aqueous solution was used in this leaching technique. Since neutralization and/or solvent extraction were not required in the separation procedure of nickel and cadmium, the closed systemization of the process becomes possible. Experimental results show that, (1) if the NH3 concentration of leaching solution is sufficiently high and the ratio of H2CO3 to NH3 is properly adjusted, both Ni(OH)2 and Cd(OH)2 react with NH3 and quickly dissolve into leaching solution, and (2) Ni(OH)2 can be converted into insoluble NiO by calcination at 500€癈, and CdO from Cd(OH)2 by calcination maintains good solubility in NH3-H2CO3 aqueous solution. As a conclusion, the recycling technique characterized by two step leaching can be developed based on such changes in dissolution behavior by calcination. Meanwhile, the yields of 99.8% for nickel and 97.6% for cadmium are obtained, and the purities of recovered nickel and cadmium are 99.9% and 98.6%, respectively.

  1. Effect of anions on Toxicity of Cadmium Applied to MIcrobial Biomass in Red Soil

    Institute of Scientific and Technical Information of China (English)

    K.S.KHAN; XIEZHENGMIAO; 等

    1997-01-01

    A laboratory incubation experiment was conducted to elucidat the effects of associated anions on toxicity of cadmium applied to microbial biomass in the red soil. Cadmium was applied at six different levels,i.e.,O(background),5,15,30,60 and 100μg g-1 soil in the form of either cadmium acetate or cadmium chloride. Application of cadmium as cadmium acetate markedly reduced the soil microbial biomass carbon compared to cadmium applied as cadmium chlorde at all the tested levels.Similarly,organic carbon to biomass carbon ration in the soil was markedly increased by increasing the level of the cadmium in the soil as cadmium acetate,while the change wa much smaller in the case of cadmium chloride at the same cadmium levels.The results suggested that due consideration should be given to the source of cadmium while deciding the cadmium levles in experiments.

  2. Cadmium induces cadmium-tolerant gene expression in the filamentous fungus Trichoderma harzianum.

    Science.gov (United States)

    Cacciola, Santa O; Puglisi, Ivana; Faedda, Roberto; Sanzaro, Vincenzo; Pane, Antonella; Lo Piero, Angela R; Evoli, Maria; Petrone, Goffredo

    2015-11-01

    The filamentous fungus Trichoderma harzianum, strain IMI 393899, was able to grow in the presence of the heavy metals cadmium and mercury. The main objective of this research was to study the molecular mechanisms underlying the tolerance of the fungus T. harzianum to cadmium. The suppression subtractive hybridization (SSH) method was used for the characterization of the genes of T. harzianum implicated in cadmium tolerance compared with those expressed in the response to the stress induced by mercury. Finally, the effects of cadmium exposure were also validated by measuring the expression levels of the putative genes coding for a glucose transporter, a plasma membrane ATPase, a Cd(2+)/Zn(2+) transporter protein and a two-component system sensor histidine kinase YcbA, by real-time-PCR. By using the aforementioned SSH strategy, it was possible to identify 108 differentially expressed genes of the strain IMI 393899 of T. harzianum grown in a mineral substrate with the addition of cadmium. The expressed sequence tags identified by SSH technique were encoding different genes that may be involved in different biological processes, including those associated to primary and secondary metabolism, intracellular transport, transcription factors, cell defence, signal transduction, DNA metabolism, cell growth and protein synthesis. Finally, the results show that in the mechanism of tolerance to cadmium a possible signal transduction pathway could activate a Cd(2+)/Zn(2+) transporter protein and/or a plasma membrane ATPase that could be involved in the compartmentalization of cadmium inside the cell. PMID:26349455

  3. Cadmium-113m as a biogeochemical tracer for cadmium in Lake Michigan

    International Nuclear Information System (INIS)

    The Lake Michigan watershed has been sampled for 113mCd. This long-lived metastable isotope of cadmium allowed independent evaluation of cadmium distribution in this dynamic ecosystem. 113mCd analysis was not hampered by contamination or loss. These are problems which have plagued stable cadmium measurements. Sensitivity and specificity were necessary concerns. 113mCd has been preconcentrated from large samples in order to obtain sufficient activity for quantification. Specificity for the gross beta activity measured was secured in a rigorous ion exchange decontamination. Confirmation of the suspected 113mCd beta source was checked by reverse tracer analysis and modified Feather analysis range-energy relationships. The 113mCd activities confirm the expected semiconservative behavior for cadmium. This behavior manifests itself in a long residence time for cadmium in Lake Michigan. The inefficiency of outflow removal, the low sedimentation rate and the unquantified sediment resuspension and release of cadmium are factors contributing to this residence time. Steady state concentration of cadmium in Lake Michigan will increase if present input rates persist

  4. A noble and single source precursor for the synthesis of metal-rich sulphides embedded in an N-doped carbon framework for highly active OER electrocatalysts.

    Science.gov (United States)

    Barman, Barun Kumar; Nanda, Karuna Kar

    2016-04-21

    Here, we demonstrate a green and environment-friendly pyrolysis route for the synthesis of metal-rich sulphide embedded in an N-doped carbon (NC) framework in the absence of sulphide ions (S(2-)). The metal-chelate complex (tris(ethylenediamine) metal(ii) sulfate) serves as a new and single source precursor for the synthesis of earth abundant and non-precious hybrid structures such as metal-rich sulphides Co9S8@NC and Ni3S2@NC when M(II) = Co(2+) and Ni(2+) and counter sulphate (SO4(2-)) ions are the source of S. Both the hybrids show superior OER activity as compared to commercial RuO2.

  5. A noble and single source precursor for the synthesis of metal-rich sulphides embedded in an N-doped carbon framework for highly active OER electrocatalysts.

    Science.gov (United States)

    Barman, Barun Kumar; Nanda, Karuna Kar

    2016-04-12

    Here, we demonstrate a green and environment-friendly pyrolysis route for the synthesis of metal-rich sulphide embedded in an N-doped carbon (NC) framework in the absence of sulphide ions (S(2-)). The metal-chelate complex (tris(ethylenediamine) metal(ii) sulfate) serves as a new and single source precursor for the synthesis of earth abundant and non-precious hybrid structures such as metal-rich sulphides Co9S8@NC and Ni3S2@NC when M(II) = Co(2+) and Ni(2+) and counter sulphate (SO4(2-)) ions are the source of S. Both the hybrids show superior OER activity as compared to commercial RuO2. PMID:26999042

  6. Reduction of Cadmium Uptake of Rice Plants Using Soil Amendments in High Cadmium Contaminated Soil: A Pot Experiment

    Directory of Open Access Journals (Sweden)

    Dian Siswanto

    2013-05-01

    Full Text Available The aims of this study were to investigate the effect of agricultural residues on reducing cadmium uptake in rice plants. The rice plants growing on no cadmium/free cadmium soils (N, Cd soils (Cds, and Cd soils each amended with 1% w/w of coir pith (CP, coir pith modified with sodium hydroxide (CPm and corncob (CC under high cadmium contaminated soil with an average 145 mg Cd kg-1 soil were investigated. The results showed that the cumulative transpiration of rice grown in various treatments under high cadmium contaminated soil followed the order: Cds > CPm ≥ CP ≥ CC. These transpirations directly influenced cadmium accumulation in shoots and husks of rice plants. The CC and CP seemed to work to reduce the cadmium uptake by rice plants indicated by accumulated cadmium in the husk that were 2.47 and 7.38 mg Cd kg-1 dry weight, respectively. Overall, transpiration tended to drive cadmium accumulation in plants for rice grown in high cadmium contaminated soil. The more that plants uptake cadmium, the lower cadmium that remains in the soil.

  7. A new test for plant bioaccessibility in sulphidic wastes and soils: A case study from the Wheal Maid historic tailings repository in Cornwall, UK.

    Science.gov (United States)

    van Veen, E M; Lottermoser, B G; Parbhakar-Fox, A; Fox, N; Hunt, J

    2016-09-01

    Currently, bioaccessibility testing at contaminated sites is dominated by techniques designed to assess oral bioaccessibility to humans. Determining the plant bioaccessibility of toxic trace elements is also important. In mining landscapes, sulphides are an important source of potentially toxic elements. Simple tests to evaluate readily leachable metals and metalloids exist but do not extract elements temporarily constrained within the sulphide fraction. Sequential extractions describe the association of trace elements with different geochemical fractions but are time consuming, costly and provide excessive detail. This paper proposes a new test for plant bioaccessibility in sulphidic mine wastes and soils that uses hydrogen peroxide to simulate environmental oxidation. The bioaccessible fraction determined is operationally defined and does not predict actual plant uptake. The test targets a) the portion of an element that is currently available in the pore water for uptake by plant roots and also b) the fraction that is temporarily constrained in sulphide minerals but may become available upon oxidation of the substrate. A case study was conducted at a historic mine waste repository site in Cornwall, U.K. where near total As concentrations were extremely elevated and Cd, Cu, Pb, Sb and Zn were also high. Our test determined that bioaccessible concentrations of As, Cd, Cu and Zn and to a lesser extent Sb and Pb were highest in samples of pyritic grey tailings. This is attributed to sulphide mineral oxidation and, particularly for Cd and Zn, the dissolution of soluble secondary minerals. High As concentrations in the marbled tailings were not bioaccessible. Results from the case study show that this new test provides useful information on the future bioaccessibility of contaminants, allowing for classification of mineralised sulphidic waste materials which otherwise cannot be obtained using established geochemical and mineralogical techniques. Furthermore, the test

  8. Defects and diffusion in semiconductors XIII an annual retrospective

    CERN Document Server

    Fisher, D J

    2011-01-01

    This thirteenth volume in the series covering the latest results in the field includes abstracts of papers which have appeared since the publication of Annual Retrospective XII (Volumes 303-304). As well as the over 300 semiconductor-related abstracts, the issue includes the original papers: ""Effect of KCl Addition upon the Photocatalytic Activity of Zinc Sulphide"" (D.Vaya, A.Jain, S.Lodha, V.K.Sharma, S.C.Ameta), ""Localized Vibrational Mode in Manganese-Doped Zinc Sulphide and Cadmium Sulphide Nanoparticles"" (M.Ragam, N.Sankar, K.Ramachandran), ""The Effect of a Light Impurity on the Elec

  9. Bireactor Electronuclear Systems with Liquid Cadmium Valve

    CERN Document Server

    Bznuni, S A; Zhamkochyan, V M; ASosnin, A N; Polanski, A; Khudaverdyan, A H

    2002-01-01

    Three main types of bireactor electronuclear systems are discussed. From the point of view of assuring high level of functional characteristics and safety bireactor electronuclear systems with booster using enriched uranium (20 %) and with a liquid cadmium valve appears to be the most effective. It is shown by means of Monte-Carlo modeling that such operation conditions can be achieved which lead to the destruction of the intermediate cadmium layer making the systems supercritical (k_{eff}>1). One can avoid the problem by using a special design of the liquid cadmium valve. In comparison with other nuclear systems (critical reactors, one-reactor electronuclear systems) cascade electronuclear systems have essential advantages allowing the decrease of the proton beam current by one order of magnitude and providing at same time the necessary level of power generation and neutron flux. Availability of both the thermal and fast cones allows one to transmute not only transuranics but also the fission products - cesi...

  10. ELECTROKINETIC REMEDIATION STUDY FOR CADMIUM CONTAMINATED SOIL

    Directory of Open Access Journals (Sweden)

    P. Bala Ramudu

    2007-09-01

    Full Text Available This paper presents the results of an experimental research undertaken to evaluate different purging solutions to enhance the removal of cadmium from spiked contaminated field soil by electrokinetic remediation. Three experiments were conducted when soil was saturated with deionised water and subsequently deionised water, ammonium citrate and sodium citrate were used as purging solutions at anode end. One experiment was conducted when the soil was saturated with ammonium citrate and itself was used as the purging solution. Results showed that 49% reduction of cadmium concentration was achieved in the case of soil saturated (washed with ammonium citrate as well as purging solution also was ammonium citrate. The soil pH and washing solutions were the most important factors in controlling the removal of cadmium in electrokinetic remediation process.

  11. Controlled Fabrication of Cd-Bi Nanoparticles via Sonochemical Method

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong-jie; LI Sheng; LA Zhi-wei; WU Zhi-shen; ZHANG Ping-yu; ZHANG Zhi-jun

    2005-01-01

    A sonochemical method for the direct controlled synthesis of Cd-Bi nanoparticles from a bulk Cd-Bi alloy is introduced. The nanoparticles were found to be monodispersed and the size distribution can be easily controlled by adjusting the ultrasonic power. The formation and the constituent of the as-prepared Cd-Bi nanoparticles were revealed by means of X-ray diffraction, differential thermal analysis and thermogravimetry, transmission electron microscopy, and electron diffraction. It was found that the Cd-Bi eutectic alloy nanoparticles are made of the hexagonal phase of metal cadmium and the rhombohedral phase of metal bismuth. In addition, we also found through tribological tests that the powder has an excellent antiwear property.

  12. Ammonia leaching of copper smelter dust and precipitation as copper sulphide; Lixiviacion amoniacal de polvos de fundicion de cobre y precipitacion como sulfuro de cobre

    Energy Technology Data Exchange (ETDEWEB)

    Morales, A.; Hevia, J. F.; Cifuentes, G.

    2009-07-01

    The effect of ammonia on the leaching of copper smelter dust and copper precipitation from these solutions as sulphide using sulfur and sulfur dioxide was studied. The precipitation was done in ammoniacal media because this solution produced more satisfactory results at room temperature that a sulphuric media. A solid was precipitated containing 60 % of copper of the dust smelter. The other waste generated contained around 80 % of the arsenic of the original copper smelter dust. Based on the preliminary results obtained in this work it will propose a procedure for the recovery of copper as sulphide from copper smelter dust with parallel confinement of arsenic. (Author) 14 refs.

  13. The Lattice Compatibility Theory: Arguments for Recorded I-III-O2 Ternary Oxide Ceramics Instability at Low Temperatures beside Ternary Telluride and Sulphide Ceramics

    Directory of Open Access Journals (Sweden)

    K. Boubaker

    2013-01-01

    Full Text Available Some recorded behaviours differences between chalcopyrite ternary oxide ceramics and telluride and sulphides are investigated in the framework of the recently proposed Lattice Compatibility Theory (LCT. Alterations have been evaluated in terms of Urbach tailing and atomic valence shell electrons orbital eigenvalues, which were calculated through several approximations. The aim of the study was mainly an attempt to explain the intriguing problem of difficulties of elaborating chalcopyrite ternary oxide ceramics (I-III-O2 at relatively low temperatures under conditions which allowed crystallization of ternary telluride and sulphides.

  14. Preparation of metal oxide nanoparticles in ionic liquid medium

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Cabo, Borja; Rodil, Eva; Soto, Ana; Arce, Alberto, E-mail: alberto.arce@usc.es [University of Santiago de Compostela, Department of Chemical Engineering, School of Engineering (Spain)

    2012-07-15

    In the present study, a facile, rapid, and environmentally friendly method was used for the preparation of metal oxide nanoparticles in an ionic liquid medium. This technique involves mixing and heating the corresponding powder material (cadmium oxide, anatase, and hematite) and the selected ionic liquid (trihexyl(tetradecyl)phosphonium chloride, [P{sub 6,6,6,14}]Cl), without any other precursors or solvents. The confirmation of the existence of nanoparticles in the ionic liquid was carried out using UV-Vis absorption spectroscopy, and its concentration was determined by X-ray fluorescence. In order to analyze the shape and size distribution, transmission electron microscopy and a ZetaSizer (DLS technique) were used; finding out that the size of the hematite nanoparticles was 10-55 nm. Nevertheless, for the cadmium oxide and the anatase nanoparticles, the size was between 2 and 15 nm. The composition of the prepared nanoparticles was studied by Raman spectroscopy. The structure of solids did not suffer any modification in their transformation to the nanoscale, as concluded from the X-ray powder diffraction analysis.

  15. Increased cadmium and lead uptake of a cadmium hyperaccumulator tomato by cadmium-resistant bacteria.

    Science.gov (United States)

    He, Lin-Yan; Chen, Zhao-Jin; Ren, Gai-Di; Zhang, Yan-Feng; Qian, Meng; Sheng, Xia-Fang

    2009-07-01

    Two cadmium (Cd)-resistant strains Pseudomonas sp. RJ10 and Bacillus sp. RJ16 were investigated for their effects on the soil Cd and lead (Pb) solubilization and promotion of plant growth and Cd and Pb uptakes of a Cd-hyperaccumulator tomato. In the heavy metal-contaminated inoculated soil, the CaCl(2)-extractable Cd and Pb were increased by 58-104% and 67-93%, respectively, compared to the uninoculation control. The bacteria produced indole acetic acid, siderophore and 1-aminocyclopropane-1-carboxylate deaminase. Root elongation assay conducted on tomato under gnotobiotic conditions demonstrated increase in root elongation of inoculated tomato seedlings compared to the control plants. An increase in Cd and Pb contents of above-ground tissues varied from 92% to 113% and from 73% to 79% in inoculated plants growing in heavy metal-contaminated soil compared to the uninoculation control, respectively. These results show that the bacteria could be exploited for bacteria enhanced-phytoextraction of Cd- and Pb-polluted soils. PMID:19368973

  16. Treatment of cadmium dust with two-stage leaching process

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The treatment of cadmium dust with a two-stage leaching process was investigated to replace the existing sulphation roast-leaching processes. The process parameters in the first stage leaching were basically similar to the neutralleaching in zinc hydrometallurgy. The effects of process parameters in the second stage leaching on the extraction of zincand cadmium were mainly studied. The experimental results indicated that zinc and cadmium could be efficiently recoveredfrom the cadmium dust by two-stage leaching process. The extraction percentages of zinc and cadmium in two stage leach-ing reached 95% and 88% respectively under the optimum conditions. The total extraction percentage of Zn and Cdreached 94%.

  17. Cadmium toxicity in the free-living nematode, Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Popham, J.D.; Webster, J.M.

    1979-10-01

    The effect of cadmium on the fecundity, growth, and fine structure of the free-living nematode Caenorhabditis elegans was studied. High concentrations of cadmium significantly decreased the fecundity and growth of these organisms. Electron microscopy showed that cadmium modifies the structure of the mitochondria in the esophagus and intestine, causes the formation of inclusion bodies in the nucleus of esophageal cells, and alters the morphology of cytosomes in the intestinal cells. The results suggest that the decreased fecundity and growth of cadmium-exposed C. elegans may be due to cadmium interfering with nutrient uptake or assimilation or both.

  18. Thermodynamic properties of cadmium in lead amalgam dilute solution

    International Nuclear Information System (INIS)

    Investigation of thermodynamic properties of cadmium dilute solutions in lead amalgam is carried out by means of electromotive force technique within 453-523 K temperature range. Cadmium thermodynamic functions are calculated: activity, activity ratio, Libbs partial energy and its excess value and integral characteristics, respectively. When changing cadmium content from 0.01 up to 0.1 χcd at T=473 K, logarithm of activity ratio does not depend on alloy composition, that is, Heury's law is fulfilled. Increase of cadmium content in amalgam results in the essential reduction of mercury and cadmium reaction

  19. Urinary excretion of cadmium and zinc among persons from Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Elinder, C.G.; Kjellstrom, T.; Linnman, L.; Pershagen, G.

    1978-06-01

    Cadmium and zinc concentrations in the urine of 132 Swedes, including 50 pairs of identical twins, were measured. Atomic absorption spectrophotometry procedures were developed for the analysis. Cadmium concentration increased with age and was higher among smokers than among nonsmokers. Estimated 24-hr excretion of cadmium among nonsmokers increased from about 0.25 to 0.40 ..mu..g in persons from 20 to 70 years old. The 24-hr cadmium excretions among nonsmokers in different age-groups fitted better to total kidney burden than to daily cadmium intake from food. Zinc excretion, on the other hand, decreased after the age of 20.

  20. Structure and function of natural sulphide-oxidizing microbial mats under dynamic input of light and chemical energy.

    Science.gov (United States)

    Klatt, Judith M; Meyer, Steffi; Häusler, Stefan; Macalady, Jennifer L; de Beer, Dirk; Polerecky, Lubos

    2016-04-01

    We studied the interaction between phototrophic and chemolithoautotrophic sulphide-oxidizing microorganisms in natural microbial mats forming in sulphidic streams. The structure of these mats varied between two end-members: one characterized by a layer dominated by large sulphur-oxidizing bacteria (SOB; mostly Beggiatoa-like) on top of a cyanobacterial layer (B/C mats) and the other with an inverted structure (C/B mats). C/B mats formed where the availability of oxygen from the water column was limited (45 μM) and continuously present. Here SOB were independent of the photosynthetic activity of cyanobacteria and outcompeted the cyanobacteria in the uppermost layer of the mat where energy sources for both functional groups were concentrated. Outcompetition of photosynthetic microbes in the presence of light was facilitated by the decoupling of aerobic chemolithotrophy and oxygenic phototrophy. Remarkably, the B/C mats conserved much less energy than the C/B mats, although similar amounts of light and chemical energy were available. Thus ecosystems do not necessarily develop towards optimal energy usage. Our data suggest that, when two independent sources of energy are available, the structure and activity of microbial communities is primarily determined by the continuous rather than the intermittent energy source, even if the time-integrated energy flux of the intermittent energy source is greater. PMID:26405833

  1. Electrochemical studies on interplay of mineralogical variation and particle size on bioleaching low grade complex sulphide ores

    Institute of Scientific and Technical Information of China (English)

    P. A. OLUBAMBI; J. H. POTGIETER; S. NDLOVU; J. O. BORODE

    2009-01-01

    The interplay of mineralogical variation and mineral phase distribution within varying particle sizes on the dissolution behaviour of a low grade complex sulphide ore was investigated through bioleaching experiments and electrochemical technique. Investigations were carried out utilizing mineralogical data on the variations in mineral and phase distribution within particle sizes of<53 μm, 53-75 μm, 75-106 μm and 106-150 μm in mixed mesophilic cultures of Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans. Electrochemical behaviour was studied using particulate electrodes from the four varying particle sizes and from massive electrodes prepared from the two major sulphide mineral rich phases (sphalerite-rich and galena-rich) and a complex mineralogical phase of the bulk ore. Bioleaching studies reveal the highest recoveries at a particle size of 75 μm, while electrochemical investigations reveal the highest dissolution at particle size of 106 μm. Electrochemical results show that sphalerite rich phase has the highest dissolution rate while galena-rich complex phase has the least. SEM studies confirm the highest bacterial attack at the sphalerite-rich phase. The discrepancies between the dissolutions within particle sizes obtained from bioleaching experiments and electrochemical studies are consistent with and attributed both to the physical and mineralogical influences. Electrochemical behaviour is influenced and controlled by galvanic interaction resulting from mineralogical variation, while bioleaching behaviour is influenced by mineralogical variation as well as physical effect of particle size.

  2. Cross effect of temperature, pH and free ammonia on autotrophic denitrification process with sulphide as electron donor.

    Science.gov (United States)

    Fajardo, Carmen; Mora, Mabel; Fernández, Isaac; Mosquera-Corral, Anuska; Campos, José Luis; Méndez, Ramón

    2014-02-01

    Autotrophic denitrification is a suitable technology to simultaneously remove oxidised nitrogen compounds and reduced sulphur compounds yielding nitrogen gas, sulphur and sulphate as the main products. In this work, several batch tests were conducted to investigate the cross effect of temperature, pH and free ammonia on the autotrophic denitrification. Denitrification efficiencies above 95% were achieved at 35°C and pH 7.5-8.0 with maximum specific autotrophic denitrifying activities up to 188mgN2g(-1)VSSd(-1). Free ammonia did not show any effect on denitrification at concentrations up to 53mg NH3-NL(-1). Different sulphide concentrations were also tested with stoichiometric nitrite and nitrate concentrations. Sulphide inhibited denitrification at concentrations higher than 200mgS(2-)L(-1). A 50% inhibition was also found at nitrite concentrations above 48mg NO2(-)-NL(-1). The maximum specific activity decreased until a value of 25mgN2g(-1) VSSd(-1) at 232mg NO2(-)-NL(-1). The Haldane model was used to describe denitrification inhibition caused by nitrite. Kinetic parameters determined from the fitting of experimental data were rmax=176mgN2g(-1)VSSd(-1), Ks=10.7mg NO2(-)-NL(-1) and Ki=34.7mg NO2(-)-NL(-1). The obtained model allowed optimising an autotrophic denitrification process by avoiding situations of inhibition and thus obtaining higher denitrification efficiencies. PMID:24216266

  3. Deformation and metamorphism of gold-sulphide lodes in the Bhukia–Jagpura gold prospect, Rajasthan: Implications for ore genesis

    Indian Academy of Sciences (India)

    S Deol; A Chattopadhyay; M Deb

    2014-02-01

    The role of polyphase deformation in controlling the emplacement of gold-quartz lodes in dilational regimes is demonstrated from the Proterozoic Bhukia–Jagpura gold prospect in south Rajasthan. Earlier researchers deciphered the gold-sulphide mineralisation event as synchronous to the second phase of deformation (D2) without convincing microstructural or metamorphic evidences. In this contribution, we correlate the deformation and metamorphic imprints in the host rocks with those in the gold-sulphide mineralised zone, and present a new interpretation for the relative timing of gold emplacement vis-á-vis deformation. The ore-forming process first involved layer-parallel influx of ore-bearing hydrothermal fluids along S1 schistosity in the host rocks, synkinematic with respect to the first phase of deformation (D1). This initial ore concentration experienced metamorphism isofacially (∼500° C at 5.3 kb) along with its host rocks during D1, and subsequently underwent extensive remobilisation, giving rise to gold-bearing silicified lodes along the hinges and axial surfaces of F2 folds during D2.

  4. Cadmium telluride quantum dots advances and applications

    CERN Document Server

    Donegan, John

    2013-01-01

    Optical Properties of Bulk and Nanocrystalline Cadmium Telluride, Núñez Fernández and M.I. VasilevskiyAqueous Synthesis of Colloidal CdTe Nanocrystals, V. Lesnyak, N. Gaponik, and A. EychmüllerAssemblies of Thiol-Capped CdTe Nanocrystals, N. GaponikFörster Resonant Energy Transfer in CdTe Nanocrystal Quantum Dot Structures, M. Lunz and A.L. BradleyEmission of CdTe Nanocrystals Coupled to Microcavities, Y.P. Rakovich and J.F. DoneganBiological Applications of Cadmium Telluride Semiconductor Quantum Dots, A. Le Cign

  5. Elektrokemisk fjernelse af cadmium fra bioasker

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; Ottosen, Lisbeth M.; Simonsen, Peter;

    Posteren viser resultater fra elektrokemiske rensningsforsøg på bioasker udført i forbindelse med PSO projekt 5205 "Elektrokemisk fjernelse af cadmium fra bioasker i pilotskala og vurdering af mulighederne for nyttiggørelse af behandlet aske i beton".......Posteren viser resultater fra elektrokemiske rensningsforsøg på bioasker udført i forbindelse med PSO projekt 5205 "Elektrokemisk fjernelse af cadmium fra bioasker i pilotskala og vurdering af mulighederne for nyttiggørelse af behandlet aske i beton"....

  6. Gamma Irradiation Synthesis and Influence the Optical and Thermal Properties of Cadmium Sulfide (CdS/Poly (Vinyl Pyrolidone Nanocomposites

    Directory of Open Access Journals (Sweden)

    Shawkat S. Gasaymeh

    2010-01-01

    Full Text Available Problem statement: Gamma irradiation has been successfully used to prepare a spherical cadmium sulfide CdS/Poly Vinylpyrolidone (PVP quantum dots nanoparticles with enhancement of their optical band gap energy and thermal properties at room temperature and under ambient pressure. Sodium thiosulfate was used as a sulfur source in an aqueous solution. The formation of lower band gap energy of CdS/PVP nanoparticles and thermal stability can be controlled by using different irradiation doses. TEM images showed that the CdS/PVP particle size tends to be smaller and with better distribution as irradiation dose increases. Approach: Gamma (γ irradiation offered many advantages for the preparation of metal nanoparticles by producing large number of hydrated electrons during γ-ray irradiation, which can reduce the metal ions to zero valiant metal particles. Results: CdS/PVP nanoparticles were successfully prepared in one-step by γ-irradiation technique in an aqueous system at room temperature and under ambient pressure. The particle size was found to be less than 10 nm based on the Transmission Electron Microscopy (TEM that depended on the irradiation doses value, which showed a well distribution with a controlled size as doses change. The presence of PVP polymer was considered an important reason that influenced the shape and the distribution of those nanoparticles. The optical band gap energy of those nanoparticles was calculated by using the UV-VIS absorption spectra. Thermal analysis TGA showed that the composite had a higher degradation temperature than the PVP alone. A possible mechanism of the formation of cadmium sulfide by irradiation system was proposed. Conclusion: This result indicated that CdSO4 can effectively dope PVP and enhance the optical and thermal properties. In addition, γ-irradiation is an effective technique for preparing inorganic/organic nanocomposites.

  7. Toxicity test: Fluorescent silicon nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Fujoka, K; Hoshino, A; Manome, Y [Department of Molecular Cell Biology, Jikei University School of Medicine, Minatoku, Tokyo 105-8461 (Japan); Hanada, S; Kanaya, F; Yamamoto, K [Research Institute, National Centre for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655 (Japan); Sato, K; Yokosuka, S; Takigami, Y; Hirakuri, K [Department of Electrical and Electronic Engineering, Tokyo Denki University, Chiyoda-ku, Tokyo 101-8457 (Japan); Shiohara, A; Tilley, R D [MacDiarmid Institute of Advanced Materials and Nanotechnology, Victoria University of Wellington, Wellington (New Zealand); Manabe, N, E-mail: kfujioka@jikei.ac.jp [Institute of Multidisciplinary Research for Advance Materials, Tohoku University, Sendai, Miyagi 980-8577 (Japan)

    2011-07-06

    Semiconductor nanoparticles ('quantum dots', QDs) are useful fluorescent materials because of their high fluorescent stability compared with existing organic fluorescent dyes. QDs were tested in many biochemical experiments, and the reported results suggested their advantages. However, when we consider their application at the clinical level, their large-scale use may be problematic because of their influence on the environment and the living body as a result of cadmium contained in existing mainstream QDs. Here we report on the characteristics of silicon particles (synthesised using the gas phase method and liquid phase method, currently in the development stage) as a substitute material, focusing on cell-level safety and the potential mechanisms of toxicity.

  8. Toxicity test: Fluorescent silicon nanoparticles

    International Nuclear Information System (INIS)

    Semiconductor nanoparticles ('quantum dots', QDs) are useful fluorescent materials because of their high fluorescent stability compared with existing organic fluorescent dyes. QDs were tested in many biochemical experiments, and the reported results suggested their advantages. However, when we consider their application at the clinical level, their large-scale use may be problematic because of their influence on the environment and the living body as a result of cadmium contained in existing mainstream QDs. Here we report on the characteristics of silicon particles (synthesised using the gas phase method and liquid phase method, currently in the development stage) as a substitute material, focusing on cell-level safety and the potential mechanisms of toxicity.

  9. Cadmium exposure and pancreatic cancer in south Louisiana.

    Science.gov (United States)

    Luckett, Brian G; Su, L Joseph; Rood, Jennifer C; Fontham, Elizabeth T H

    2012-01-01

    Cadmium has been hypothesized to be a pancreatic carcinogen. We test the hypothesis that cadmium exposure is a risk factor for pancreatic cancer with a population-based case-control study sampled from a population with persistently high rates of pancreatic cancer (south Louisiana). We tested potential dietary and nondietary sources of cadmium for their association with urinary cadmium concentrations which reflect long-term exposure to cadmium due to the accumulation of cadmium in the kidney cortex. Increasing urinary cadmium concentrations were significantly associated with an increasing risk of pancreatic cancer (2nd quartile OR = 3.34, 3rd = 5.58, 4th = 7.70; test for trend P ≤ 0.0001). Potential sources of cadmium exposure, as documented in the scientific literature, found to be statistically significantly associated with increased risk of pancreatic cancer included working as a plumber, pipefitter or welder (OR = 5.88) and high consumption levels of red meat (4th quartile OR = 6.18) and grains (4th quartile OR = 3.38). Current cigarette smoking, at least 80 pack years of smoking, occupational exposure to cadmium and paints, working in a shipyard, and high consumption of grains were found to be statistically significantly associated with increased concentrations of urinary cadmium. This study provides epidemiologic evidence that cadmium is a potential human pancreatic carcinogen. PMID:23319964

  10. Cadmium Exposure and Pancreatic Cancer in South Louisiana

    Directory of Open Access Journals (Sweden)

    Brian G. Luckett

    2012-01-01

    Full Text Available Cadmium has been hypothesized to be a pancreatic carcinogen. We test the hypothesis that cadmium exposure is a risk factor for pancreatic cancer with a population-based case-control study sampled from a population with persistently high rates of pancreatic cancer (south Louisiana. We tested potential dietary and nondietary sources of cadmium for their association with urinary cadmium concentrations which reflect long-term exposure to cadmium due to the accumulation of cadmium in the kidney cortex. Increasing urinary cadmium concentrations were significantly associated with an increasing risk of pancreatic cancer (2nd quartile OR = 3.34, 3rd = 5.58, 4th = 7.70; test for trend P≤0.0001. Potential sources of cadmium exposure, as documented in the scientific literature, found to be statistically significantly associated with increased risk of pancreatic cancer included working as a plumber, pipefitter or welder (OR = 5.88 and high consumption levels of red meat (4th quartile OR = 6.18 and grains (4th quartile OR = 3.38. Current cigarette smoking, at least 80 pack years of smoking, occupational exposure to cadmium and paints, working in a shipyard, and high consumption of grains were found to be statistically significantly associated with increased concentrations of urinary cadmium. This study provides epidemiologic evidence that cadmium is a potential human pancreatic carcinogen.

  11. Intermetallic nanoparticles

    Science.gov (United States)

    Singh, Dileep; Yusufoglu, Yusuf; Timofeeva, Elena; Routbort, Jules

    2015-07-14

    A process for preparing intermetallic nanoparticles of two or more metals is provided. In particular, the process includes the steps: a) dispersing nanoparticles of a first metal in a solvent to prepare a first metal solution, b) forming a reaction mixture with the first metal solution and a reducing agent, c) heating the reaction mixture to a reaction temperature; and d) adding a second metal solution containing a salt of a second metal to the reaction mixture. During this process, intermetallic nanoparticles, which contain a compound with the first and second metals are formed. The intermetallic nanoparticles with uniform size and a narrow size distribution is also provided. An electrochemical device such as a battery with the intermetallic nanoparticles is also provided.

  12. Study of cadmium electrochemical deposition in sulfate medium

    Energy Technology Data Exchange (ETDEWEB)

    Montiel, T.; Solorza, O.; Sanchez, H.

    2000-03-01

    The cadmium electrochemical deposition process from sulfate medium was studied by means of different electrochemical techniques in both stationary and nonstationary diffusion regimes. The kinetics of the electrochemical reduction of cadmium on solid cadmium electrodes was examined and the kinetic parameters are presented, as well as the diffusion coefficient derived from the different techniques. Temperature has an important effect on the cadmium reduction kinetics, and the activation energy of the process was evaluated. The electrochemical deposition of cadmium is a complex process due to the coexistence of adsorption and nucleation processes; the adsorbed electroactive species appears to be Cd{sup +2}, and a mechanism for cadmium electrodeposition on solid cadmium electrodes is proposed.

  13. Murine strain differences and the effects of zinc on cadmium concentrations in tissues after acute cadmium exposure

    Energy Technology Data Exchange (ETDEWEB)

    King, L.M. [ARS USDA, Germplasm and Gamete Physiology Lab., Beltsville, MD (United States); Anderson, M.B. [Dept. of Anatomy, Tulane Univ. School of Medicine, New Orleans, LA (United States); Sikka, S.C. [Dept. of Urology, Tulane Univ. School of Medicine, New Orleans, LA (United States); George, W.J. [Dept. of Pharmacology, Tulane Univ. School of Medicine, New Orleans, LA (United States)

    1998-10-01

    The role of strain differences in cadmium tissue distribution was studied using sensitive (129/J) and resistant (A/J) mice. These murine strains have previously been shown to differ in their susceptibility to cadmium-induced testicular toxicity. Cadmium concentration was measured in testis, epididymis, seminal vesicle, liver, and kidney at 24 h after cadmium chloride exposure (4, 10, and 20 {mu}mol/kg CdCl{sub 2}). The 129/J mice exhibited a significant increase in cadmium concentration in testis, epididymis, and seminal vesicle at all cadmium doses used, compared to A/J mice. However, cadmium concentrations in liver and kidney were not different between the strains, at any dose, indicating that cadmium uptake is similar in these organs at 24 h. These murine strains demonstrate similar hepatic and renal cadmium uptake but significantly different cadmium accumulation in the reproductive organs at 24 h. The mechanism of the protective effect of zinc on cadmium toxicity was studied by assessing the impact of zinc acetate (ZnAc) treatment on cadmium concentrations in 129/J mice after 24 h. Zinc pretreatment (250 {mu}mol/kg ZnAc), given 24 h prior to 20 {mu}mol/kg CdCl{sub 2} administration, significantly decreased the amount of cadmium in the testis, epididymis, and seminal vesicle of 129/J mice, and significantly increased the cadmium content of the liver after 24 h. Cadmium levels in the kidney were unaffected at this time. Zinc pretreatment also prevented the cadmium-induced decrease in testicular sperm concentration and epididymal sperm motility seen in 129/J mice. These findings suggest that the differences in the two murine strains may be attributed partly to the differential accumulation of cadmium in murine gonads. This may be caused by strain differences in the specificity of cadmium transport mechanisms. The protective role of zinc in cadmium-induced testicular toxicity in the sensitive strain may be due to an interference in the cadmium uptake by susceptible

  14. Effects of bacteria on cadmium bioaccumulation in the cadmium hyperaccumulator plant Beta vulgaris var. cicla L.

    Science.gov (United States)

    Chen, Su; Chao, Lei; Sun, Lina; Sun, Tieheng

    2013-01-01

    To investigate the effects of two cadmium-tolerant bacteria, Staphylococcus pasteuri (S. pasteuri X1) and Agrobacterium tumefaciens (A. tumefaciens X2), on cadmium uptake by the cadmium hyperaccumulator plant Beta vulgaris var. cicla L., a pot experiment with artificially contaminated soil was conducted. The results demonstrated that both cadmium-tolerant bacteria enhanced the dry weight of Beta vulgaris var. cicla L. The total dry weights of plants in the control CK20, S. pasteuri X1 and A. tumefaciens X2 treatments were 0.85, 1.13, and 1.38 g/pot, respectively. Compared with the control CK20 findings, the total dry weight of plants was increased by 32.8 and 61.1% after inoculation with S. pasteuri X1 and A. tumefaciens X2, respectively, indicating that A. tumefaciens X2 more strongly promoted the growth of Beta vulgaris var. cicla L. than S. pasteuri X1. In addition, inoculation with S. pasteuri X1 and A. tumefaciens X2 significantly (p < 0.05) promoted cadmium uptake by plants and improved the bioaccumulation of cadmium by the plants from the soil. Moreover, the inoculation of S. pasteuri X1 and A. tumefaciens X2 effectively facilitated the transfer of cadmium in the soil from the Fe-Mn oxide and residual fractions to the soluble plus exchangeable and weakly specially adsorbed fractions in the rhizosphere soils of plants. The bacterial enhancement of cadmium phytoavailability might provide a potential and promising method to increase the efficiency of phytoextraction. PMID:23488173

  15. Urinary cadmium and estimated dietary cadmium in the Women's Health Initiative.

    Science.gov (United States)

    Quraishi, Sabah M; Adams, Scott V; Shafer, Martin; Meliker, Jaymie R; Li, Wenjun; Luo, Juhua; Neuhouser, Marian L; Newcomb, Polly A

    2016-01-01

    Cadmium, a heavy metal dispersed in the environment as a result of industrial and agricultural applications, has been implicated in several human diseases including renal disease, cancers, and compromised bone health. In the general population, the predominant sources of cadmium exposure are tobacco and diet. Urinary cadmium (uCd) reflects long-term exposure and has been frequently used to assess cadmium exposure in epidemiological studies; estimated dietary intake of cadmium (dCd) has also been used in several studies. The validity of dCd in comparison with uCd is unclear. This study aimed to compare dCd, estimated from food frequency questionnaires, to uCd measured in spot urine samples from 1,002 participants of the Women's Health Initiative. Using linear regression, we found that dCd was not statistically significantly associated with uCd (β=0.006, P-value=0.14). When stratified by smoking status, dCd was not significantly associated with uCd both in never smokers (β=0.006, P-value=0.09) and in ever smokers (β=0.003, P-value=0.67). Our results suggest that because of the lack of association between estimated dCd and measured uCd, dietary estimation of cadmium exposure should be used with caution in epidemiologic studies.

  16. A novel magneto-fluorescent microsphere: Preparation and characterization of polystyrene-supported Fe{sub 3}O{sub 4} and CdS nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kaboudin, Babak, E-mail: kaboudin@iasbs.ac.ir; Ghaderian, Abolfazl

    2013-10-01

    Novel sulfonated polystyrene microsphere containing Fe{sub 3}O{sub 4} and CdS nanoparticles have been prepared and characterized. A thorough structural characterization has been carried out by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) images, VSM data, EDS, and photoluminescence spectroscopy. The presence of the magnetic nanoparticles (Fe{sub 3}O{sub 4}) and CdS nanoparticles on the polystyrene microspheres has been demonstrated. Cadmium diethyl dithiophosphate (CDDP) has been used as a 3 in 1 precursor (cadmium, sulfur, and ligand source) for the synthesis of high-quality CdS nanoparticles on polystyrene microsphere containing Fe{sub 3}O{sub 4} nanoparticles. This novel composite exhibits both fluorescence and magnetism properties that may be used in a novel bioprobe.

  17. RISK ASSESSMENT FOR CADMIUM IN PHOSPHATE FERTILIZERS

    Science.gov (United States)

    Cadmium induced renal tubular dysfunction occurred where subsistence rice farmers produced their lifetime dietary rice on Zn-mine waste contaminated soils in Japan and other Asian countries. Research has shown that polished rice Cd is greatly increased while grain Zn is not incre...

  18. Field scale behaviour of cadmium in soil.

    NARCIS (Netherlands)

    Boekhold, A.E.

    1992-01-01

    Although total heavy metal contents of soil are often used to express the degree of contamination, they are of little value to judge environmental effects. The main objective of this thesis was to develop and test methodologies with which environmental risks of cadmium pollution of field soils can b

  19. Mobiliteit van cadmium in de bodem

    NARCIS (Netherlands)

    Chardon, W.J.

    1984-01-01

    The adsorption of cadmium by twelve Dutch soils was investigated under widely varying circumstances. The adsorption can be described with the Freundlich equation; the parameters of this equation can be predicted using the properties of the soil (pH, organic carbon and clay content).The adsorption ap

  20. Cadmium isotope variations in the Southern Ocean

    NARCIS (Netherlands)

    Xue, Z.; Rehkämper, M.; Horner, T.J.; Abouchami, W.; Middag, R.; van de Flierd, T.; de Baar, H.J.W.

    2013-01-01

    Cadmium concentrations and isotope compositions were determined for 47 seawater samples from the high nutrient low chlorophyll (HNLC) zone of the Atlantic sector of the Southern Ocean. The samples include 13 surface waters from a transect of the Weddell Gyre and 3 depth profiles from the Weddell Sea

  1. Study on sulphide capacity of CaO-SiO2-Al2O3-MgO-FetO slags

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The sulphide capacity of CaO-SiO2-Al2O3-MgO-FetO slags was studied at 1773 K using gas-slag equilibrium techniques.Utilizing a Pt crucible, the slag was equilibrated with a mixture of gases, namely, CO, CO2, SO2 and N2 to provide the partial pressure of oxygen and sulphur. It was shown that at fixed FetO and Al2O3 contents and a fixed {(%CaO)+(%MgO)}/(%SiO2) ratio, the sulphide capacity decreases with increasing MgO content. At a constant (%CaO)/(%SiO2) ratio and constant MgO and Al2O3 contents, increasing the FetO content of the slags also results in an increase of the sulphide capacity. The rising basicity of (%CaO)/(%SiO2) from 1.0 to 1.4 at fixed MgO, FetO and Al2O3 contents significantly increases the sulphide capacity.

  2. Simultaneous determination of nanomole amounts of sulphur dioxide and hydrogen sulphide by flow injection analysis with on-line preconcentration by means of capillary denuder tubes.

    Science.gov (United States)

    Achilli, Marco; Gács, Istvan

    2002-01-01

    A simple and rapid method for trace determination of SO2 and H2S in gaseous samples by using a flow injection system with on line preconcentration on capillary denuder is described. The gaseous samples are led through a 0.4 M sulphamic acid solution, retaining nitrogen dioxide, ammonia and hydrogen chloride. The sulphur dioxide is collected from the carrier gas stream (250 cm3 min-1) as sulphuric acid in a capillary denuder tube coated with a thin layer of 0.01-0.03 M hydrogen peroxide solution of 0.05 mM sulphuric acid; hydrogen sulphide passes into a second tube coated with 0.075 mM sodium sulphide solution of 0.1 M aqueous sodium hydroxide. The films containing the sulphuric acid and the sodium sulphide, respectively, are eluted with the corresponding circulating absorbent streams and pass through the detectors. Sulphuric acid is detected by conductimetry and sulphide is determined spectrophotometrically at 230 nm. If nanoequivalent amounts of H2S are present in the sample containing a large concentration of SO2 (SO2/H2S concentration ratio > 20), the sulphur dioxide is filtered out of the sample gas stream by solid sodium hydrogen carbonate. A limit of detection of 3.5 micrograms m-3 is obtained.

  3. The importance of sulphide binding for leaching of heavy metals from contaminated Norwegian marine sediments treated by stabilization/solidification.

    Science.gov (United States)

    Sparrevik, Magnus; Eek, Espen; Grini, Randi Skirstad

    2009-07-01

    Over time, Norwegian fjords and harbour areas have received contaminants from industrial activities and urban run-off, and measures to remediate contaminated marine sediments are therefore needed. Stabilization/solidification (S/S) technology, in which the contaminated marine sediments are mixed with cement and other binding agents, has been shown to be a promising remediation technology. This paper summarizes a study of the environmental effect of stabilization, highlighting the importance of sulphide binding governing the leaching of heavy metals from the S/S of contaminated marine sediments. The study is a part of a research project focusing on developing effective methods for S/S of contaminated seabed sediments for use in new construction areas. Four cementitious binders were tested on sediments from six different locations: Bergen, Gilhus, Grenland, Hammerfest, Sandvika and Trondheim. The sediments differed with respect to properties such as concentration of contaminants, water content, organic content and grain size distribution. Portland cement, Portland cement with fly ash, industry cement, and sulphate resistant cement, were tested as binders. The leaching from the S/S sediments after 28 days of curing was measured by using a standard leaching batch test (EN 12457-2: 2003), with seawater as leaching agent. The eluate was analysed for pH and redox, as well as content of heavy metals and organic contaminants. Available volatile sulphide (AVS) and simultaneously extractable metals (SEM) were also measured in the sediments. This paper focuses on the leaching of lead (Pb) and copper (Cu). A reduced leaching of Pb after stabilization was observed for the mixtures, whereas the leaching of Cu from Hammerfest sediments increased substantially after stabilization for all cementitious additions. Experiments show that Hammerfest samples had lower values of AVS than the other sediments. This was confirmed by the SEM/AVS analysis, highlighting the importance of

  4. Cadmium phytoextraction potential of different Alyssum species

    Energy Technology Data Exchange (ETDEWEB)

    Barzanti, R., E-mail: rbarzanti@supereva.it [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy); Colzi, I., E-mail: ilariacolzi@hotmail.it [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy); Arnetoli, M., E-mail: miluscia@gmail.com [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy); Gallo, A., E-mail: galloalessia@hotmail.com [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy); Pignattelli, S., E-mail: sara.pignattelli@gmail.com [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy); Gabbrielli, R., E-mail: gabbrielli@unifi.it [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy); Gonnelli, C., E-mail: cristina.gonnelli@unifi.it [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy)

    2011-11-30

    Highlights: Black-Right-Pointing-Pointer The possibility of using serpentine plants for phytoextraction of Cd was investigated. Black-Right-Pointing-Pointer Variation in Cd tolerance, accumulation and translocation in three Alyssum plants with different phenotypes were found. Black-Right-Pointing-Pointer Alyssum montanum showed higher Cd tolerance and accumulation than the Ni hyperaccumulator Alyssum bertolonii. Black-Right-Pointing-Pointer As for the kinetic parameters of the Cd uptake system, A. montanum presented a low apparent K{sub m} value. Black-Right-Pointing-Pointer The V{sub max} values were not significantly different among the plants. - Abstract: This work was planned for providing useful information about the possibility of using serpentine adapted plants for phytoextraction of cadmium, element scarcely represented in such metalliferous environment. To this aim, we investigated variation in cadmium tolerance, accumulation and translocation in three Alyssum plants with different phenotypes: Alyssum bertolonii, that is a serpentine endemic nickel hyperaccumulator, and two populations of Alyssum montanum, one adapted and one not adapted to serpentine soils. Plants were hydroponically cultivated in presence of increasing concentrations of CdSO{sub 4} for two weeks. For the metal concentration used in the experiments, the three different Alyssum populations showed variation in cadmium tolerance, accumulation and content. The serpentine adapted population of A. montanum showed statistically higher cadmium tolerance and accumulation than A. bertolonii and the population of A. montanum not adapted to serpentine soil thus deserving to be investigated for phytoextraction purposes. Furthermore, as for the kinetic parameters of the cadmium uptake system, A. montanum serpentine population presented a low apparent K{sub m} value, suggesting a high affinity for this metal of its uptake system, whereas the V{sub max} values were not significantly different among the

  5. Cadmium and Chrome Concentrations in Human Milk

    Directory of Open Access Journals (Sweden)

    Sima Nazarpour

    2014-04-01

    Full Text Available Introduction: Nutrition of children has the highest priority in any program aimed at children's health care. Milk contaminated with various toxic elements can have adverse effects on children's health. This study aimed to determine the concentration of heavy metals including cadmium(Cd and chromium (Cr of breast feeding women’s milk in Varamin. Methods: This is a cross sectional study. In the present study, chromium and cadmium levels in milk of 100 mothers attending clinics in the city of Varamin were measured in four to eight weeks after delivery, using atomic absorption spectrometry. Results: The mean values (±SD of Cd and Cr in human milk were 5±6.9 μg/ml and 3±2.7 μg/ml respectively. Result of Linear regression showed that cadmium levels were higher in breast milk of people living close to the factory or industrial center. Also, the chromium levels were higher in the breast milk of women in cases of: Smoking by spouses, consumption of imported rice, consumption of mineral water, and living close to the factory or an industrial center. Conclusion: This study showed that the relationship of some factors such as living near a factory or an industrial center, smoking by spouse, the type of consumed rice and water, with the level of cadmium and chromium. Cadmium and chromium levels of breast milk in this study were higher than the levels of these elements mentioned in the reviewed articles and international standard. Because some variables, such as living near a factory or an industrial center, smoking by spouse, the type of consumed rice and water can affect the amount of entering elements in breast milk. Actions can be taken to reduce or eliminate these variables in order to decrease the mentioned elements in human milk.

  6. Hepatoprotective activity of Moringa oleifera against cadmium toxicity in rats

    Directory of Open Access Journals (Sweden)

    Reetu Toppo

    2015-04-01

    Full Text Available Aim: The present investigation has been conducted to evaluate the hepatoprotective activity of Moringa oleifera against cadmium-induced toxicity in rats. Materials and Methods: For this study, 18 Wistar albino rats were taken. Control group, Group I rats were given cadmium chloride @ 200 ppm per kg and Group II rats were treated with M. oleifera extract @ 500 mg/kg along with cadmium chloride @ 200 ppm per kg (daily oral for 28 days. On 29th day, animals were slaughtered and various parameters were determined. Serum biomarkers, oxidative stress parameters, histomorphological examination were carried out with estimation of cadmium concentration in liver tissues. Results: Oral administration of cadmium chloride @ 200 ppm/kg for 28 days resulted in a significant increase in aspartate aminotransferase (AST, alanine transaminase (ALT, alkaline phosphatase (ALP, significant (p≤0.01 increase of lipid peroxidation (LPO and decrease in superoxide dismutase (SOD, and increase in cadmium accumulation in liver. Treatment with M. oleifera @ 500 mg/kg significantly (p<0.01 decreased the elevated ALP, AST, ALT, LPO levels and increase in SOD levels, and as compared to cadmium chloride treated group. However, there was no significant difference in cadmium concentration in liver when compared with cadmium chloride treated group. Conclusion: The study conclude that supplementation of M. oleifera (500 mg/kg, daily oral for 28 days has shown protection against cadmium-induced hepatotoxicity.

  7. Modelling of Cadmium Transport in Soil-Crop System

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A model for simulating cadmium transport in a soil-plant system was built using a commercial simu lating program named Powersim on the basis of input-output processes happening in the soil-plant system.Convective and dispersive transport processes of cadmium in soil profile are embedded. Simulations on a daily base have been done up to a total simulating time of 250 years. Results show that applications of sewage sludge and fertilizer at the simulated rates would only cause slight cadmium accumulations in each layer of the soil, and cadmium accumulation would be levelling off, reaching an equilibrium concentrations layer by layer downward after certain time. The time scale to reach an equilibrium concentration varies from 10 years for the top three layers to over 250 years for the bottom layers. Plant cadmium uptake would increase from 52 ug m-2 under initial soil cadmium concentrations to 65 μg m-2 under equilibrium soil cadmium concentrations, which would not exceed the maximum allowable cadmium concentration in wheat grains. Main parameters which influence cadmium accumulation and transport in soil are total cadmium input, rainfall, evaporation, plant uptake and soil properties.

  8. Simulation of substrate erosion and sulphate assimilation by Martian low-viscosity lava flows: implications for the genesis of precious metal-rich sulphide mineralisation on Mars

    Science.gov (United States)

    Baumgartner, Raphael; Baratoux, David; Gaillard, Fabrice; Fiorentini, Marco

    2016-04-01

    On Earth, high temperature mafic to ultramafic lava flows, such as komatiites and ferropicrites of the Archean and Proterozic eons, can be hosts to Ni-Cu-PGE sulphide mineralisation. Mechanical/thermo-mechanical erosion and assimilation of sulphur-rich crustal rocks is ascribed as the principal mechanism that leads to sulphide supersaturation, batch segregation and subsequent accumulation of metal-enriched magmatic sulphides (e.g., Bekker et al., Science, 2009). In order to investigate the likelihood of the occurrence of similar sulphide mineralisation in extraterrestrial magmatic systems, we numerically modelled erosion and assimilation during the turbulent emplacement of Martian lavas, some of which display chemical and rheological analogies with terrestrial komatiites and ferropicrites, on a variety of consolidated sedimentary sulphate-rich substrates. The modelling approach relies on the integration of i) mathematical lava erosion models for turbulent flows (Williams et al., J. Geophys. Res., 1998), ii) thermodynamic volatile degassing models (Gaillard et al., Space Sci. Rev., 2013), and iii) formulations on the stability of sulphides (Fortin et al., Geochim. Cosmochim. Acta, 2015). A series of scenarios are examined in which various Martian mafic to ultramafic mantle-derived melts emplace over, and assimilate consolidated sulphate-rich substrates, such as the sedimentary lithologies (i.e., conglomerates, sandstones and mudstones) recently discovered at the Gale Crater landing site. Our modellings show that lavas emplacing over consolidated sedimentary substrate rather than stiff basaltic crust, are governed by relatively high cooling and substrate erosion rates. The rapid assimilation of sulphate, which serves as a strongly oxidising agent, could result in dramatic sulphur loss due to increased volatile degassing rates at fO2 ≳QFM-1. This effect is further enhanced with increased temperature. Nevertheless, sulphide supersaturation in the way of sulphate

  9. The influence of size, shape, and surface coating on the stability of aqueous nanoparticle suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Mulvihill, M.J.; Habas, S.E.; La Plante, I.J.; Wan, J.; Mokari, T.

    2010-09-03

    In response to the rapid development and emerging commercialization of nanoparticles, fundamental studies concerning the fate of nanoparticles in the environment are needed. Precise control over the nanoparticle size, shape, and surface coating of cadmium selenide particles modified with thiolate ligands has been used to analyze the effects of nanoparticle design on their stability in aqueous environments. Nanoparticle stability was quantified using the concept of critical coagulation concentration (CCC) in solutions of sodium chloride. These investigations characterized the instability of the ligand coatings, which varied directly with chain length of the capping ligands. The stability of the ligand coatings were characterized as a function of time, pH, and ionic strength. Ligand dissociation has been shown to be a primary mechanism for nanoparticle aggregation when short-chain (C2-C6) ligands are used in the ligand shell. Stable nanoparticle suspensions prepared with long chain ligands (C11) were used to characterize nanoparticle stability as a function of size and shape. A linear relationship between particle surface area and the CCC was discovered and was found to be independent of nanoparticle shape. Quantitative analysis of nanoparticle size, shape, and surface coating demonstrated the importance of ligand stability and particle surface area for the prediction of nanoparticle stability.

  10. Radiation chemical route for preparation of metal nanoparticles

    International Nuclear Information System (INIS)

    Nanoparticles show properties that are neither seen in the bulk or at atomic level. The unusual properties are governed by quantum size effect. Due to this various methodologies have been endeavored to control the size of the particles. In the present work we show the use of two complimentary techniques (radiation and photo) to synthesize and control the size of the metal particles. In-situ synthesis of fine silver, thallium and cadmium particles has been carried out by gamma-irradiation and electron pulse irradiation at room temperature in the pre-organized gel of polyacrylamide or cyclodextrin cavity. The role of generation of nuclei in high concentrations in stabilization of metal nanoparticles in hydrophobic cavity is shown. Similarly the importance of entrapment of metal ions in the polymer matrix during its formation is highlighted. The work is further extended to exploit the microemulsion droplets for stabilization of Cd nanoparticles. Utility of pulse radiolysis in probing the mechanism of the formation of metal nanoparticles is also shown. Ultrafast laser pulses were employed to control the morphology of the pre-prepared Pt nanoparticles. The changes in reduction of shape and size are considered to occur through melting and vaporization of the nanoparticles. Pt nanoparticles were coated on the inner walls of the tubular pyrex reactor and tested for their catalytic activity for oxidation of CO. It was observed that Pt nanoparticles prepared in the presence of a stabilizer (gelatin) showed a higher tendency to adhere to the inner walls of the pyrex reactor as compared to that prepared in the presence of silica nanoparticles. The catalyst was found to be active at ≥150 degree C giving CO2. Chemically reduced Pt nanoparticles stabilized on silica nanoparticles gave ∼7% CO conversion per hr. However, radiolytically prepared Pt nanoaprticles stabilized by gelatin gave ∼10% conversion per hr. The data indicates that catalytic oxidation of CO takes place by

  11. Sulphide phases in Y zeolite for hydro-treatment reactions; Phase sulfures dans une zeolithe Y pour l'hydrotraitement

    Energy Technology Data Exchange (ETDEWEB)

    Leyrit, P.

    1999-06-28

    Several types of single (Mo, Co, Pd, Pt) or binary (MoCo, PdCo, PtCo) sulphides phases supported on a HY zeolite were studied. The catalysts were first prepared and characterised in the oxide form. Their reactivity was then evaluated in toluene hydrogenation and 4.6-dimethyl-dibenzo-thiophene hydro-desulfurization reactions. Characterisation of sulphide phases supported on HY zeolite was carried out by elemental analysis, X-Ray Diffraction (XRD), Transmission Electron Microscopy and Scanning Transmission Electron Microscopy (STEM), Extended X-Ray Absorption Fine Structure (EXAFS) and Temperature Programmed Reduction coupled with HS analysis. The results show that. compared with alumina supported catalysts, zeolite used as a support enables extremely active catalysts to be obtained. It appears in particular that molybdenum sulphide phases inside the zeolite have a very high intrinsic activity at low molybdenum content. This activity is attributed to highly dispersed molybdenum sulphide phases differing from MoS{sub 2} slabs and probably present as clusters. The influence of cobalt depends of its concentration. Thus at low loadings cobalt has a strong negative effect. It has been shown, in the molybdenum case, that cobalt interaction leads to an increase in the sulphur content of the molybdenum phases. At higher cobalt loading, the formation of a mixed phase is possible but the degree of promotion remains limited. This work emphasises the advantages of using zeolite supported sulphide phases, and especially Mo and Pd phases, in the hydro-treatment reactions. It seems however that single phases present a greater interest than binary phases. (author)

  12. Studying microfungi-mineral interactions in sulphide-bearing waste-rock dumps: a 7 years survey in the Libiola mine, North-Eastern Italy

    Science.gov (United States)

    Marescotti, P.; Cecchi, G.; Di Piazza, S.; Lucchetti, G.; Zotti, M.

    2015-12-01

    Sulphide-bearing waste-rock dumps represent complex geological systems characterised by high percentages of low-grade mineralisations and non-valuable sulphides (such as pyrite and pyrrhotite). The sulphide oxidation triggers acid mine drainage (AMD) processes and the release of several metals of environmental concern. The severe physicochemical properties of these metal-contaminated environments tend to inhibit soil forming processes and represent an important stress factor for the biotic communities by exerting a strong selective pressure. Some macro- and micro-fungi are pioneer and extremophile organisms, which may survive and tolerate high concentrations of toxic metals in contaminated environments. Many studies show the fungal capability to bioaccumulate, biosorb, and store in their cells a high concentration of ecotoxic metals. A 7 years multidisciplinary survey was carried out in the Libiola sulphide mine. The results evidenced that the waste rock dumps of the area are characterized by an extremely poor flora and a specific mycobiota, due to the soil acidity, high concentration of trace metals, and unavailability or paucity of nutrients and organic matter. Our studies allowed the complete mineralogical, geochemical, and mycological characterization of one of the biggest dumps of the mine. 30 microfungal vital strains were isolated in pure cultures and studied with molecular and morphological approach, for their identification. The results allowed the isolation of some rare and important extremophilic species. Penicillium was the most recurrent genus, together with Trichoderma and Cladosporium. In particular, Penicillium glandicola is a rare species previously isolated from cave or arid environments, whereas P. brevicompactum is one of the most important fungi for metal corrosion. Hence, some bioaccumulation tests allowed to select a Trichoderma harzianum strain efficient to uptake Cu and Ag from pyrite-bearing soils, highlighting its central role in fungal

  13. In vitro and in vivo toxicity of CdTe nanoparticles.

    Science.gov (United States)

    Zhang, Yongbin; Chen, Wei; Zhang, Jun; Liu, Jing; Chen, Guangping; Pope, Carey

    2007-02-01

    Cadmium telluride (CdTe) nanoparticles exhibit strong and stable fluorescence that is attractive for many applications such as biological probing and solid state lighting. The evaluation of nanoparticle toxicity is important for realizing these practical applications. However, no systematic studies of CdTe nanoparticle toxicity have been reported. We investigated and compared the size- and concentration-dependent cytotoxicity of CdTe nanoparticles in human hepatoma HepG2 cells using the MTT assay. CdTe nanoparticles elicited cytotoxicity in a concentration- and size-dependent manner, with smaller-sized particles exhibiting somewhat higher potency. Lesser cytotoxicity of partially purified CdTe-Red particles (following methanol precipitation and resuspension) suggested that free cadmium ions may contribute to cytotoxicity. We also evaluated the acute toxicity of CdTe-Red particles following intravenous exposure in male rats (2 micromol/kg). Few signs of functional toxicity or clinical (urinary or blood) changes were noted. Interestingly, motor activity was transiently reduced (2 hours after treatment) and then significantly increased at a later timepoint (24 hours after dosing). These studies provide a framework for further characterizing the in vitro and in vivo toxic potential of different types of CdTe nanoparticles and suggest that the nervous system may be targeted by these nanoparticles under some conditions.

  14. Preparation and characterization of chemically deposited nickel sulphide film and its application as a potential counter electrode

    Science.gov (United States)

    Ray, Jaymin; Patel, Mitesh; Ghediya, Prashant; Chaudhuri, Tapas K.

    2016-07-01

    Nickel sulphide (NiS) film has emerged as a counter electrode in many applications, such as thin film batteries, dye sensitized solar cells, and supercapacitors. In this regard, we report the direct liquid coating of pure hexagonal NiS films on glass using a precursor solution of nickel-thiourea complex. A uniform and void free film is observed using scanning electron microscopy. The room temperature electrical conductivity of ˜5 × 103 S cm-1 and the positive thermoelectric power (+6 μV K-1) specify p-type conduction. The temperature variation conductivity in the range 77-300 K depicts the transition of NiS films from conducting to semi-conducting behaviour at certain transition temperatures. Preliminary results from a cyclic voltammetry study shows the feasibility of NiS films as counter electrodes.

  15. Electrochemical and surface studies on the passivity of a dental Pd-based casting alloy in alkaline sulphide solution

    International Nuclear Information System (INIS)

    The corrosion and tarnish behavior of a dental casting Pd-25Ag-18Cu-12Au alloy in 0.1% Na2S solution at 37 deg. C was investigated using potentiodynamic polarization and spectrocolorimetric techniques. The surface film was characterized by X-ray photoelectron spectroscopy (XPS). This alloy exhibited markedly higher resistance to corrosion and tarnish than did the Ag-20Pd-18Cu-12Au alloy in current clinical use. XPS spectra indicated the presence of a thin sulphide film composed of PdS. It was found that the PdS film is very protective and is responsible for the passivity of the Pd-25Ag-18Cu-12Au alloy in 0.1% Na2S solution

  16. Monte Carlo simulation optimisation of zinc sulphide based fast-neutron detector for radiography using a 252Cf source

    Science.gov (United States)

    Meshkian, Mohsen

    2016-02-01

    Neutron radiography is rapidly extending as one of the methods for non-destructive screening of materials. There are various parameters to be studied for optimising imaging screens and image quality for different fast-neutron radiography systems. Herein, a Geant4 Monte Carlo simulation is employed to evaluate the response of a fast-neutron radiography system using a 252Cf neutron source. The neutron radiography system is comprised of a moderator as the neutron-to-proton converter with suspended silver-activated zinc sulphide (ZnS(Ag)) as the phosphor material. The neutron-induced protons deposit energy in the phosphor which consequently emits scintillation light. Further, radiographs are obtained by simulating the overall radiography system including source and sample. Two different standard samples are used to evaluate the quality of the radiographs.

  17. How do esters and dimethyl sulphide concentrations affect fruity aroma perception of red wine? Demonstration by dynamic sensory profile evaluation.

    Science.gov (United States)

    Lytra, Georgia; Tempere, Sophie; Marchand, Stéphanie; de Revel, Gilles; Barbe, Jean-Christophe

    2016-03-01

    Our study focused on variations in wine aroma perception and molecular composition during tasting over a period of 30min. In parallel, dynamic analytical and sensory methods were applied to study changes in the wines' molecular and aromatic evolution. Dynamic sensory profile evaluations clearly confirmed the evolution of the wine's fruity notes during sensory analysis, highlighting significant differences for red-berry and fresh fruit as well as black berry and jammy fruit, after 5 and 15min, respectively. Dynamic analytical methods revealed a decrease in ester and dimethyl sulphide (DMS) concentrations in the first few minutes. Sensory profiles of aromatic reconstitutions demonstrated that the aromatic modulation of fruity notes observed during wine tasting was explained by changes in ester and DMS concentrations. These results revealed that variations in concentrations of DMS and esters during wine tasting had a qualitative impact, by modulating fruity aromas in red wine.

  18. Preparation of copper sulphide clusters in organic-inorganic composites of Langmuir-Blodgett films of amphiphilic Schiff bases

    Indian Academy of Sciences (India)

    G Hemakanthi; Aruna Dhathathreyan; T Ramasami; D Möbius

    2001-04-01

    Copper sulphide clusters were prepared in Langmuir-Blodgett films of copper complexes of amphiphilic Schiff bases-3,4-dimethoxy-N-benzylidene hexadeylamine (I) and 3,4-dimethoxy-N-benzylidene-4 -(hexadecylamino) benzylamine (II) The clusters obtained were analysed using UV-Vis spectroscopy and optical microscopy. Brewster angle microscopic studies on monolayers of I and II at air/water interface showed formation of needle-like domains which seem to cluster faster in I than in II. Atomic force microscopy (AFM) studies also showed fairly uniform sized clusters in II whereas in the case of I they seem to show varying sizes. From the results it is concluded that -elongation in the polar head groups leads to controlled cluster sizes in compound II as compared to those in compound I.

  19. Electrochemical Quantification of Single Nucleotide Polymorphisms Using Nanoparticle Probes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guodong; Lin, Yuehe

    2007-08-29

    We report a new approach for electrochemical quantification of single-nucleotide polymorphisms (SNPs) using nanoparticle probes. The principle is based on DNA polymerase I (klenow fragment)-induced coupling of the nucleotide-modified nanoparticle probe to the mutant sites of duplex DNA under the Watson-Crick base pairing rule. After liquid hybridization events occurred among biotinylated DNA probes, mutant DNA, and complementary DNA, the resulting duplex DNA helixes were captured to the surface of magnetic beads through a biotin-avidin affinity reaction and magnetic separation. A cadmium phosphate-loaded apoferritin nanoparticle probe, which is modified with nucleotides and is complementary to the mutant site, is coupled to the mutant sites of the formed duplex DNA in the presence of DNA polymerase. Subsequent electrochemical stripping analysis of the cadmium component of coupled nanoparticle probes provides a means to quantify the concentration of mutant DNA. The method is sensitive enough to detect 21.5 attomol mutant DNA, which will enable the quantitative analysis of nucleic acid without polymerase chain reaction pre-amplification. The approach was challenged with constructed samples containing mutant and complementary DNA. The results indicated that it was possible to accurately determine SNPs with frequencies as low 0.01. The proposed approach has a great potential for realizing an accurate, sensitive, rapid, and low-cost method of SNP detection.

  20. Assessment and management of risk to wildlife from cadmium

    International Nuclear Information System (INIS)

    Cadmium, a nonessential heavy metal that comes from natural and anthropogenic sources, is a teratogen, carcinogen, and a possible mutagen. Assessment of potential risk from cadmium requires understanding environmental exposure, mainly from ingestion, although there is some local exposure through inhalation. Chronic exposure is more problematic than acute exposure for wildlife. There is evidence for bioaccumulation, particularly in freshwater organisms, but evidence for biomagnification up the food chain is inconsistent; in some bird studies, cadmium levels were higher in species that are higher on the food chain than those that are lower. Some freshwater and marine invertebrates are more adversely affected by cadmium exposure than are birds and mammals. There is very little experimental laboratory research on the effects of cadmium in amphibians, birds and reptiles, and almost no data from studies of wildlife in nature. Managing the risk from cadmium to wildlife involves assessment (including ecological risk assessment), biomonitoring, setting benchmarks of effects, regulations and enforcement, and source reduction

  1. Study on electrokinetic remediation of cadmium contaminated soils

    Institute of Scientific and Technical Information of China (English)

    SHI Wen-xin; CUI Chong-wei; YU Shui-li; FENG Wei-ming

    2007-01-01

    Kaolinite from a lead-zinc mining district, which was spiked with cadmium, has been treated by electrokinetics to investigate effects of treatment time and applied voltage gradient. The results showed that the increased test duration had induced a higher removal rate of cadmium. Being treated for 7 days, cadmium was removed from kaolinite dramatically. It was also found that higher removal rate happened when a higher voltage gradient was applied and cadmium accumulated near the cathode because pH increased. Increase of pH near the cathode caused accumulation of cadmium. Moreover, it was observed that cation exchange membrane which was placed between kaolinite and cathode could make pH lower than the initial value and avoid the higher pH near the cathode. As a result, the high concentration accumulation of cadmium near the cathode was avoided.

  2. Research and Development of Cadmium Sulphoselenide Red Pigment

    Institute of Scientific and Technical Information of China (English)

    WU Jianfeng; LI Kun; XU Xiaohong; ZHANG Yaxiang; XU Xiaoyang; LAO Xinbin

    2015-01-01

    Cadmium sulphoselenide was synthesized continuous substitution solid solution and the only known pigment to yield bright red color on ceramic decoration. Encapsulated cadmium sulphoselenide pigments could yield abundant hues from yellow to red with high opacity at high temperature. The color generation has a linear function relation with the substitution rate. The encapsulation formation process of zirconium silicate encapsulated cadmium sulphoselenide was shown. Insufifcient encapsulation efifciency and potential hazard to human and environment had limited the industrial application of cadmium sulphoselenide red pigment. Ink-jet printing decoration required ifne size cadmium sulphoselenide red pigment on ceramic decoration. The review mainly focused on the synthesis techniques and industrial application of cadmium sulphoselenide red pigment.

  3. In search of biomonitors for cadmium: cadmium content of wild Swedish fauna during 1973-1976.

    Science.gov (United States)

    Frank, A

    1986-12-01

    Forty-five species of birds and 22 species of mammals of the terrestrial and aquatic fauna, herbivores as well as carnivores, were investigated during the period 1973-1976 for cadmium-accumulating properties in order to find biomonitors for cadmium in the Swedish environment. The herbivores of the terrestrial fauna, birds as well as mammals, are preferred to carnivores, since they demonstrate generally higher renal Cd levels. The moose (Alces alces), roe deer (Capreolus capreolus) and hare (Lepus europeus and Lepus timidus) were found to be suitable as biomonitors because of their common occurrence and uniform geographical distribution. The eider duck (Somateria mollissima), although a short-distance migrating bird whose diet is composed mainly of mussels and crustaceans, and which lives along a great part of the Swedish coastline, is suggested as a biomonitor of cadmium for the aquatic environment. The accumulation rate of cadmium in the kidneys is rapid. Renal levels of cadmium in the parts per million range are reached 10 weeks after hatching. Juvenile birds should be collected for monitoring purposes before leaving their feeding domains at the end of the summer. PMID:3810147

  4. Oral cadmium exposure of adults in Germany. 1: Cadmium content of foodstuffs and beverages.

    Science.gov (United States)

    Müller, M; Anke, M; Hartmann, E; Illing-Günther, H

    1996-04-01

    The cadmium contents of 94 and 105 foodstuffs bought in six-fold repetition in 1988 and in nine-fold repetition in 1991, respectively were analysed within the framework of a market-basket study. These foodstuffs were typical of German eating habits. Additionally, 170 samples of drinking water were investigated. The cadmium concentrations of the foodstuffs were comparable with results of recent studies carried out in Europe and North America. Fruit, milk and dairy products, sugar and sugar-rich foodstuffs as well as beverages showed mean cadmium contents cakes and pastries as well as farinaceous products were within the range of 20-40 ng/g. The most important bread, cakes and pastries (wheat and rye bread, toasted bread, rolls) contained 25-35 ng/g. A median cadmium concentration of 0.2 micrograms/l was found in the drinking water. As expected, liver and kidneys showed the highest cadmium levels of 73 and 204 ng/g, respectively on average. PMID:8718751

  5. Hepatotoxicity of Cadmium and Roles of Mitigating Agents

    Directory of Open Access Journals (Sweden)

    Elias Adikwu

    2013-12-01

    Full Text Available There are increasing reports on cadmium associated hepatotoxicity, due to these reports this study reviewed relevant literature on cadmium associated hepatotoxicity with emphasis on doses, route of administration, salt forms (cadmium compounds and the roles of mitigating agents. Reports have shown that continuous exposure of the liver to cadmium has led to hepatotoxicity. Humans are generally exposed to cadmium by two main routes, inhalation and ingestion. In this study, evaluation of relevant literature showed that irrespective of route of administration and salt forms cadmium hepatotoxicity is dose and time dependent. Cadmium associated hepatotoxicity manifested through impaired functions of hepatic biomarkers (transaminases, enzymatic and non enzymatic antioxidants. Histopathological damage to liver architecture manifested as swelling of hepatocytes, focal necrosis, hepatocytes degeneration, dilatation of ribosomes, damage of membrane-bounded lysosomes, nuclear pyknosis and cytoplasm vacuolization. Deterioration of mitochondrial cristae, deposition of collagen fibrils, hypertrophy of kuffer cells, congestion in central veins and sinusoids, infiltration of mixed inflammatory cells and peripheral hemorrhage also occurred. Hepatotoxic effect of cadmium was mitigated by Vitamin C, Vitamin E, Manganese (11 Chloride, N-acetylcysteine and Selenium. Extracts of plant origin including Solanum tuberosum, Calycopteris floribunda Hibiscus sabdariffa mitigated cadmium induced hepatotoxicity. Chemical substances of animal origin including honey and camel milk were reported to have ameliorated cadmium induced hepatotoxicity. One of the mechanisms of cadmium induced hepatotoxicity is reported to be associated with the up regulation of reactive oxygen species (oxidative stress which caused oxidative damage to lipid contents of membranes and direct liver injury. Conclusion cadmium is dose and time dependently hepatotoxic irrespective of route of administration

  6. Extraction-photometric determination of cadmium in meat products

    Energy Technology Data Exchange (ETDEWEB)

    Krylova, A.N.; Malyarova, M.A.; Zhulenko, V.N.

    1986-06-01

    As a result of industrial discharges, burning of solid and liquid fuels, and recycling of metal scrap, cadmium compounds enter the atmosphere and drop into the water and soil causing contamination. In this paper, a method was developed for determining cadmium in meat products. It involves wet ashing the sample, extractive separation of the cadmium as the diethyldithiocarbamate, reextraction, and determination as cadmium dithizonate or as a complex with 2,2'-dipyridyl. The detection limit with dithizone is 0.005 mg/kg and with 2,2'-dipyridyl 0.05 mg/kg. An analysis is shown to take less than 60 minutes.

  7. Cadmium elemination from phosphoric acid by ionic flotation

    International Nuclear Information System (INIS)

    The ion flotation process for the recovery of cadmium from wet phosphoric acid (30%P2O5) has been studied. This technique combines a chemical recation between the collector and the cadmium to form a precipitate (sublate) which is carried to the surface of the solution by air bubbles. the resulting foam containing the cadmium may then separated from solution. The influence of parameters such as collector and cadmium concentration as well as iron content have been investigated for the case a synthetic acid (30% P2O5). The result have been applied to the industrial phosphoric acid produced from Djebel Onk's phosphates (Algeria)

  8. Bioremoval of cadmium by lemna minor in different aquatic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Uysal, Yagmur [Dept. of Environmental Engineering, Kahramanmaras Sutcu Imam University, Kahramanmaras (Turkey); Taner, Fadime [Dept. of Environmental Engineering, Mersin University, Mersin (Turkey)

    2010-04-15

    This study was undertaken to determine the cadmium removal efficiency of Lemna minor when it was used for treatment of wastewater having different characteristics, i. e., pH, temperature and cadmium concentration. Plants were cultivated in different pH solutions (4.5-8.0) and temperatures (15-35 C) in the presence of cadmium (0.1-10.0 mg/L) for 168 h. The amount of biomass obtained in the study period, the concentrations of cadmium in the tissues and in the media and net uptake of cadmium by Lemna have been determined for each condition. The percentages of cadmium uptake (PMU) and bioconcentration factors (BCF) were also calculated. The highest accumulation was obtained for the highest cadmium concentration of 10.0 mg Cd/L as 11.668 mg Cd/g at pH 6.0, and as 38.650 mg Cd/g at 35 C and pH 5.0. The cadmium accumulation gradually increased with initial concentration of the medium, but the opposite trend was observed for the PMU. However, the maximum PMU was obtained as 52.2% in the solution with the lowest concentration of 0.1 mg Cd/L. A mathematical model was used to describe the cadmium uptake and the equation obtained was seen to fit the experimental data very well. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  9. Effects of Cadmium on BMP Induced Bone Formation

    Institute of Scientific and Technical Information of China (English)

    陈秋生; 徐顺清

    2003-01-01

    To demonstrate the direct effects of cadmium on activities of bone morphogenetic protein (BMP), a complex containing BMP and cadmium chloride (CdCl2) was implanted beneath the abdominal skin of young male Wistar rats. The activity of BMP was studied by observing the histological changes, and measuring the activity of alkaline phosphatase (ALP) and acid phosphatase (ACP) and calcium content of the implants at different time points. Our results showed that during bone formation induced by BMP, cadmium inhibited the activities of osteoblasts and osteoclasts, and slowed the deposition of calcium. It is concluded that cadmium can directly affect biological activities of BMP directly.

  10. β—Correction Spectrophotometric Determination of Cadmium with Cadion

    Institute of Scientific and Technical Information of China (English)

    郜洪文

    1995-01-01

    Cadmium has been determined by β-correction spectrophotometry with cadion,p-nitrobenzenediazoaminoaz-obenzone,and a non-ionic surfactant,tuiton X-100.The real absorbance of a Cd-cadion chelate in the colored solution can be accurately determined and the complex-ratio of cadion with Cd(II) has been worked out to be 2.Beer's law is obeyed over the concentration range of 0-0.20mg/1 cadmium and the detec-tion limit for cadmium is only 0.003mg/1.Satisfactory experimental results are presented with respect to the determination of trace cadmium in wastewaters.

  11. Elektrokemisk fjernelse af cadmium fra bioasker

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; Ottosen, Lisbeth M.; Simonsen, Peter;

    Hosliggende rapport formidler resultaterne fra PSO-projektet: ”Elektrokemisk fjernelse af cadmium fra bioasker” (PSO-F&U 3206), finansieret af Elkraft System og Energi E2 A/S. Projektet blev gennemført i perioden 01.05.2003 – 30.06.2004, og partnerne var Energi E2 A/S, BYG-DTU og Krüger A/S, med...... BYG-DTU som den primært udførende part. Projektets formål var at undersøge, om den elektrodialytiske rensningsmetode kunne bruges til at reducere indholdet af cadmium i asker fra biobrændsel (f.eks. træflis og halm) med henblik på nyttiggørelse af askerne. Projektet havde nær sammenhæng med det...

  12. Electron mobility in mercury cadmium telluride

    Science.gov (United States)

    Patterson, James D.

    1988-01-01

    A previously developed program, which includes all electronic interactions thought to be important, does not correctly predict the value of electron mobility in mercury cadmium telluride particularly near room temperature. Part of the reason for this discrepancy is thought to be the way screening is handled. It seems likely that there are a number of contributors to errors in the calculation. The objective is to survey the calculation, locate reasons for differences between experiment and calculation, and suggest improvements.

  13. Prevention of cadmium bioaccumulation by herbal adaptogens

    OpenAIRE

    K Bharavi; A. Gopala Reddy; G S Rao; Ravi Kumar, P.; D Srinivas Kumar; P Prabhu Prasadini

    2011-01-01

    Objectives : To evaluate the effect of various herbal adaptogens such as shade-dried powders of Withania somnifera, Ocimum sanctum, Asperagus recemosus, Andrographis paniculata, Asphaltum panjabinum (Shilajith), Gymnema sylvestre, Spirulina platensis, and Panex ginseng on cadmium (Cd)-induced oxidative stress and its accumulation in broiler chicken. Materials and Methods : A total of 80 male broiler chicks of day old age were randomly assigned to 10 equal groups. Group 1 birds were fed wi...

  14. ELECTROKINETIC REMEDIATION STUDY FOR CADMIUM CONTAMINATED SOIL

    OpenAIRE

    P. Bala Ramudu; R. P. Tiwari; Srivastava, R. K.

    2007-01-01

    This paper presents the results of an experimental research undertaken to evaluate different purging solutions to enhance the removal of cadmium from spiked contaminated field soil by electrokinetic remediation. Three experiments were conducted when soil was saturated with deionised water and subsequently deionised water, ammonium citrate and sodium citrate were used as purging solutions at anode end. One experiment was conducted when the soil was saturated with ammonium citrate and itself wa...

  15. Bioavailability of cadmium from linseed and cocoa

    DEFF Research Database (Denmark)

    Hansen, Max; Rasmussen, Rie Romme; Sloth, Jens Jørgen

    2014-01-01

    for the food authorities in order to give correct advises to the population. The aim of this study was to investigate the bioavailability of cadmium from whole linseed, crushed linseed, cocoa and cadmium chloride in rats. An experiment where 40 rats were divided into 4 groups and a control group and dosed...... with whole linseed, crushed linseed, cocoa and CdCl2 for 3 weeks was performed. Linseed or cocoa made up 10% of the feed (by weight) and was added as a replacement for carbohydrate source. The rats were dosed for 3 weeks and the cadmium content in the rats' kidneys was measured by ICPMS as a biomarker...... be measured in the kidney compared to the calculated total intake was as follows: Control 2.0 %, Crushed linseed 0.9 %, whole linseed, 1.5 %, cocoa 0.7 % and CdCl2 4.6 %. Based on this study it could not be concluded that the bioavailability in rats form whole linseed is lower that for crushed linseed...

  16. Cadmium biosorption rate in protonated Sargassum biomass

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J.; Volesky, B. [McGill Univ., Montreal, Quebec (Canada). Dept. of Chemical Engineering

    1999-03-01

    Biosorption of the heavy metal ion Cd{sup 2+} by protonated nonliving brown alga Sargassum fluitans biomass was accompanied by the release of hydrogen protons from the biomass. The uptake of cadmium and the release of proton matched each other throughout the biosorption process. The end-point titration methodology was used to maintain the constant pH 4.0 for developing the dynamic sorption rate. The sorption isotherm could be well represented by the Langmuir sorption model. A mass transfer model assuming the intraparticle diffusion in a one-dimensional thin plate as a controlling step was developed to describe the overall biosorption rate of cadmium ions in flat seaweed biomass particles. The overall biosorption mathematical model equations were solved numerically yielding the effective diffusion coefficient D{sub e} about 3.5 {times} 10{sup {minus}6} cm{sup 2}/s. This value matches that obtained for the desorption process and is approximately half of that of the molecular diffusion coefficient for cadmium ions in aqueous solution.

  17. Soil ecotoxicity assessment using cadmium sensitive plants

    International Nuclear Information System (INIS)

    The crop plants, sorghum and cucumber, can be used as indicator species to assess ecotoxicity of soils contaminated by cadmium. - Four crop plant species (sweet corn, Zea may; wheat, Triticum aestivum; cucumber, Cucumis sativus; and sorghum, Sorghum bicolor) were tested to assess an ecotoxicity in cadmium-amended soils. The measurement endpoints used were seed germination and seedling growth (shoot and root). The presence of cadmium decreased the seedling growth. The medium effective concentration values (EC50) for shoot or root growth were calculated by the Trimmed Spearman-Karber method. Due to the greater accumulation of Cd to the roots, root growth was a more sensitive endpoint than shoot growth. Bioavailability and transport of Cd within plant were related to concentration and species. The ratio of bioaccumulation factor (BAF) in the shoots to the roots indicated high immobilization of Cd in the roots. Seed germination was insensitive to Cd toxicity, and is not recommended for a suitable assay. Among the test plants and test endpoints, root growth of sorghum and cucumber appears to be a good protocol to assess ecotoxicity of soils contaminated by Cd

  18. Soil ecotoxicity assessment using cadmium sensitive plants

    Energy Technology Data Exchange (ETDEWEB)

    An, Youn-Joo

    2004-01-01

    The crop plants, sorghum and cucumber, can be used as indicator species to assess ecotoxicity of soils contaminated by cadmium. - Four crop plant species (sweet corn, Zea may; wheat, Triticum aestivum; cucumber, Cucumis sativus; and sorghum, Sorghum bicolor) were tested to assess an ecotoxicity in cadmium-amended soils. The measurement endpoints used were seed germination and seedling growth (shoot and root). The presence of cadmium decreased the seedling growth. The medium effective concentration values (EC50) for shoot or root growth were calculated by the Trimmed Spearman-Karber method. Due to the greater accumulation of Cd to the roots, root growth was a more sensitive endpoint than shoot growth. Bioavailability and transport of Cd within plant were related to concentration and species. The ratio of bioaccumulation factor (BAF) in the shoots to the roots indicated high immobilization of Cd in the roots. Seed germination was insensitive to Cd toxicity, and is not recommended for a suitable assay. Among the test plants and test endpoints, root growth of sorghum and cucumber appears to be a good protocol to assess ecotoxicity of soils contaminated by Cd.

  19. CdS nanoparticles: structural and energetical correlations

    Energy Technology Data Exchange (ETDEWEB)

    Farias, Patricia M.A. de [Departamento de Biofisica e Radiobiologia, CCB, Universidade Federal de Pernambuco, Recife, PE (Brazil)]. E-mail: pmaf@ufpe.br; Santos, Beate S. [Departamento de Ciencias Farmaceuticas, CCS, Universidade Federal de Pernambuco, Recife, PE (Brazil); Longo, Ricardo L. [Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, 50740-540 Recife, PE (Brazil); Ferreira, Ricardo [Departamento de Biofisica e Radiobiologia, CCB, Universidade Federal de Pernambuco, Recife, PE (Brazil); Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, 50740-540 Recife, PE (Brazil); Cesar, Carlos L. [Departamento de Eletronica Quantica, IFGW, Universidade Estadual de Campinas, Campinas, SP (Brazil)

    2005-01-15

    It is well known that the quantum confinement effects are closely related to the existence of different behavior for the same material composition. Due to the reduced size scale of the nanoparticles, the most part of their forming atoms are at the particle surface, which needs to be as stable as possible, to avoid phenomena such as dissolution and photodegradation. This way, methodologies for semiconductor nanoparticles obtention shall take into account the size, shape and energy of the final product. However, the relationship between these parameters is not yet clearly understood for nanometric systems, specially for those ones which are smaller than 20 nm. In this work, we present and discuss experimental and theoretical data obtained for nanoparticles of the semiconductor cadmium sulfide (CdS), in order to contribute for the understanding of the correlation between energetical and structural properties of nanometric systems in the quantum confinement regime.

  20. Reduction of Cadmium Uptake of Rice Plants Using Soil Amendments in High Cadmium Contaminated Soil: A Pot Experiment

    OpenAIRE

    Dian Siswanto; Parinda Suksabye; Paitip Thiravetyan

    2013-01-01

    The aims of this study were to investigate the effect of agricultural residues on reducing cadmium uptake in rice plants. The rice plants growing on no cadmium/free cadmium soils (N), Cd soils (Cds), and Cd soils each amended with 1% w/w of coir pith (CP), coir pith modified with sodium hydroxide (CPm) and corncob (CC) under high cadmium contaminated soil with an average 145 mg Cd kg-1 soil were investigated. The results showed that the cumulative transpiration of rice grown in various treatm...

  1. Influence of a high level of dietary cadmium on cadmium content in milk, excretion, and cow performance

    Energy Technology Data Exchange (ETDEWEB)

    Miller, W.J.; Lampp, B.; Powell, G.W.; Salotti, C.A.; Blackmon, D.M.

    1967-01-01

    Three Holstein cows were each given 3.0 g of cadmium daily (two equal doses) for two weeks by gelatin capsules. There was a sharp drop in concentrate consumption for the first few days of cadmium administration but, by the second week, consumption returned to normal. Milk production declined sharply for several days and then increased appreciably, but to a level still substantially lower than that of controls during the last five days cadmium was given. When cadmium treatments ceased, milk production increased by 50%. Fat content of milk was elevated considerably during the week when production was most reduced. Cows given cadmium lost considerable weight. There were no other clinical manifestations of toxicity. As determined by the chromic oxide indicator method and twice-daily grab samples, fecal excretion of cadmium for the second week averaged 82% of that given. The cadmium level in the urine was below the limits of detectability of the method (0.5 ppm of urine). The cadmium content of the milk was less than 0.1 ppm of the milk, which was the lower reliability limit of the procedure used. On this basis less than 0.22% of the amount administered appeared in the milk. In vitro studies demonstrated that cadmium combines with the casein and whey protein fractions of the milk readily, with the amount combined being linear when levels from 1.0 to 25.0 ppm are added to milk. Smaller amounts were present in the lactose and mineral fractions.

  2. The distribution of trace elements in a range of deep-sea sulphide ore deposits and their impact on seafloor mining

    Science.gov (United States)

    Fallon, E. K.; Scott, T. B.; Brooker, R. A.

    2015-12-01

    Acid rock drainage is a natural weathering process that is often exacerbated by mining activities, common in onshore sulphide ore deposits, that can lead to considerable environmental impact. A similar 'weathering process' occurs at seafloor massive sulphide (SMS) ore deposits. In contrast to the onshore situation, the expected consequence in the marine environment is often considered to be oxide formation, negligible metal release and minimal net acid generation due to the high buffering capacity of seawater and low solubility of iron at near neutral pH. However, no dissolution studies exist that emulate the true composition of sulphide ore deposits that either sit passively on the seafloor or are actively mined in this colder, more saline, and alkaline environment. In particular, these deposits will include a variety of minerals, and it is the interaction of these minerals and inclusions in regards to galvanic cells that can subsequently increase the dissolution of metals into the water column. Any heavy metal release that is not balanced by subsequent oxidation and precipitation, has the potential to produce toxicity for benthic ecosystems, bioaccumulation and dispersal through currents. The present work has sought to provide a pilot investigation on the deep sea weathering of sulphide minerals, by identifying the mineral phases, trace elements and potential galvanic couples that may arise in sulphide mineral samples collected from various tectonic settings. Samples have been analysed using EMPA and LA-ICPMS in order to identify the range of trace elements and toxins that may be contributed to the water column, especially heavy metals and environmental toxins (e.g. Fe, Cu, Zn, Pb, Co, Ni, Cd, As, Sb, Sn, Hg). Our observations raise important questions about which ore deposits could have more or less environmental impact during any mining activity. These observations will be used to design oxidative dissolution experiments at deep-sea conditions utilising the

  3. Cadmium sulfate complexing with thiourea during preparation of cadmium sulfide films

    International Nuclear Information System (INIS)

    Composition of complexes deposited from cadmium sulfate and thiourea(TU) aqueous solution is studied. Its influence on cadmium sulfide film deposition during solution spraying is ascertained. It is shown that with increase of TU concentration in aqueous solution gradual substitution of TU molecules for the first sphere SO42- ions takes place. As a result CdS deposition from these solutions is initiated when the ratio of CdSO4:TU concentrations is 1:2 and for prepartation of uniform films a five-fold TU excess as a minimum is necessary

  4. Correlative characteristic of cadmium in soils of steppe Dnieper region

    Directory of Open Access Journals (Sweden)

    N. M. Tsvetkova

    2015-09-01

    Full Text Available Much attention is paid to searching for methods of establishing environmental standards for objective assessment of admissibility of anthropogenic load on the biosphere. The main pollutants of the environment are xenobiotics; heavy metals such as cadmium occupy hold a special place among them. Cadmium is one of the most dangerous environmental toxic agents, belonging to the 1stclass of hazard. Due to insufficient and fragmented information available on the distribution of cadmium in the city edaphotopes, it’s necessary to conduct additional research, taking into account the properties of soils and the biological characteristics of every element. The paper shows the ratio of cadmium in soils and soil-forming rocks of steppe Dnieper region. Environmental assessment of cadmium content in Dniprodzerzhinsk city soilsis made, and the problem of topsoil contamination of the city as a territory of high anthropogenic load is considered. It is found that the content of cadmium down the profile in natural soil increases. Enrichment of the topsoil with cadmium occurs due to contamination. The value of movable forms content, expressed as a percentage of the total content, varies from 12% to 70%, providing the evidence of the technogenic origin of cadmium in Dniprodzerzhinsk city topsoil. General and proximate correlation analyses of interrelation of soil cadmium and specifically selected characteristics of soil (pH, humus, sulfate ions, dry solid, chloride ions, total alkalinity, hygroscopic moisture were made. It is established that cadmium concentration in the movable forms of natural soils of the steppe Dnieper region depends primarily on pH value. With the increase in pH value, concentration of movable cadmium in soil increases.

  5. Cadmium induces transcription independently of intracellular calcium mobilization.

    Directory of Open Access Journals (Sweden)

    Brooke E Tvermoes

    Full Text Available BACKGROUND: Exposure to cadmium is associated with human pathologies and altered gene expression. The molecular mechanisms by which cadmium affects transcription remain unclear. It has been proposed that cadmium activates transcription by altering intracellular calcium concentration ([Ca(2+](i and disrupting calcium-mediated intracellular signaling processes. This hypothesis is based on several studies that may be technically problematic; including the use of BAPTA chelators, BAPTA-based fluorescent sensors, and cytotoxic concentrations of metal. METHODOLOGY/PRINCIPAL FINDING: In the present report, the effects of cadmium on [Ca(2+](i under non-cytotoxic and cytotoxic conditions was monitored using the protein-based calcium sensor yellow cameleon (YC3.60, which was stably expressed in HEK293 cells. In HEK293 constitutively expressing YC3.60, this calcium sensor was found to be insensitive to cadmium. Exposing HEK293::YC3.60 cells to non-cytotoxic cadmium concentrations was sufficient to induce transcription of cadmium-responsive genes but did not affect [Ca(2+](i mobilization or increase steady-state mRNA levels of calcium-responsive genes. In contrast, exposure to cytotoxic concentrations of cadmium significantly reduced intracellular calcium stores and altered calcium-responsive gene expression. CONCLUSIONS/SIGNIFICANCE: These data indicate that at low levels, cadmium induces transcription independently of intracellular calcium mobilization. The results also support a model whereby cytotoxic levels of cadmium activate calcium-responsive transcription as a general response to metal-induced intracellular damage and not via a specific mechanism. Thus, the modulation of intracellular calcium may not be a primary mechanism by which cadmium regulates transcription.

  6. Critical review of animal carcinogenesis by cadmium and its inorganic compounds

    International Nuclear Information System (INIS)

    Animal carcinogenic biassays relative to 6 inorganic cadmium substances (cadmium metal, cadmium oxide, cadmium sulfide, cadmium sulfate, cadmium chloride and cadmium acetate) are reviewed (speciation). Critical evaluation of literature data on carcinogenicity has been performed by making reference to E.C. guidelines of good laboratory practice. There are few data on routes relevant for human risk assessment: experiments on inhalation demonstrate lung carcinogenicity of cadmium oxide, cadmium sulfide, cadmium sulfate and cadmium chloride in rats but not in mice nor in hamsters; no carcinogenic effects of cadmium compounds are observed following oral administration. For routes of less or no relevance for human risk assessment, some results are clearly positive: subcutaneous injection induces cancers in situ (various cadmium compounds), testicular tumours (cadmium sulfate and cadmium chloride) and prostatic tumours (cadmium chloride) but such effects are not observed using relevant malignancies in rats. With respect to other no relevant routes (intraperitoneal, intrarenal...) tumours are incidentally produced in situ, but not in remote organs. Numerous studies fail to demonstrate cadmium carcinogenicity, but methodologically acceptable negative ones are very limited in number. Accordingly strain dependent effects and dose effect relationship could not be thoroughly assessed

  7. Biopolymeric nanoparticles

    Directory of Open Access Journals (Sweden)

    Sushmitha Sundar, Joydip Kundu and Subhas C Kundu

    2010-01-01

    Full Text Available This review on nanoparticles highlights the various biopolymers (proteins and polysaccharides which have recently revolutionized the world of biocompatible and degradable natural biological materials. The methods of their fabrication, including emulsification, desolvation, coacervation and electrospray drying are described. The characterization of different parameters for a given nanoparticle, such as particle size, surface charge, morphology, stability, structure, cellular uptake, cytotoxicity, drug loading and drug release, is outlined together with the relevant measurement techniques. Applications in the fields of medicine and biotechnology are discussed along with a promising future scope.

  8. New route for preparation of luminescent mercaptoethanoate capped cadmium selenide quantum dots

    Indian Academy of Sciences (India)

    Manoj E Wankhede; Shaukatali N Inamdar; Aparna Deshpande; Aniket R Thete; Renu Pasricha; Sulabha K Kulkarni; Santosh K Haram

    2008-06-01

    We report a synthesis of cadmium selenide quantum dots (Q-CdSe) by refluxing a mixture of cadmium acetate, selenium powder, sodium sulfite and 2-mercaptoethanol in N,N′-dimethyl formamide (DMF)/water solution. X-ray and electron diffractions suggest the formation of hexagonal phase of size quantized CdSe. Based on TEM analysis, the formation of nanoparticles with an average diameter of 3.5 ± 0.5 nm is inferred. Their sols in DMF and dimethyl sulphoxide (DMSO) gave characteristic absorption peaks at 300 nm and 327 nm, which is attributed to the formation of high quality, size quantized CdSe particles. Extracted particles from the sol were readily redispersed in DMF and DMSO, which were diluted further with water without losing their optical and colloidal properties. FTIR spectroscopy suggested the formation of 2-mercaptoethanol thiolate on the particle surface, with free –OH groups available for linkage. Sols in DMSO and their solutions in water displayed an intense photoluminescence (PL).

  9. Seasonal variations of coastal sedimentary trace metals cycling: insight on the effect of manganese and iron (oxy)hydroxides, sulphide and organic matter.

    Science.gov (United States)

    Dang, Duc Huy; Lenoble, Véronique; Durrieu, Gaël; Omanović, Dario; Mullot, Jean-Ulrich; Mounier, Stéphane; Garnier, Cédric

    2015-03-15

    The combination of analysis, multivariate treatment (PCA) and chemical speciation calculation confirmed the control of Fe, Mn, sulphide and organic matter on metals dynamics in coastal sediments (0-5 cm surface sediments and sediments cores) of Toulon Bay (NW Mediterranean). The temporal monitoring of the physic-chemical parameters as well as the dissolved/particulate minor (Fe/Mn) and trace elements (i.e. Ag, Cd, Co, Cu, Ni, Pb, Zn, …) concentrations in porewaters and sediments were assessed. Multivariate treatment revealed different behaviours for marine elements, terrestrial ones and contaminants. Seasonal variations of metals mobilization in porewater were observed, related to diagenesis activity. Element mobility was studied by selective extractions (ascorbate, acid and alkaline) on sediments. Thermodynamic simulation (PHREEQC) was performed to calculate the elemental dissolved speciation, the mineral saturation index and then to simulate the solid/liquid interaction through precipitation processes, studying the contrasted influence of dissolved organic matter and sulphide.

  10. Use of ESI-MS to determine reaction pathway for hydrogen sulphide scavenging with 1,3,5-tri-(2-hydroxyethyl)-hexahydro-s-triazine

    DEFF Research Database (Denmark)

    Madsen, Henrik Tækker; Søgaard, Erik Gydesen

    2012-01-01

    was used to investigate the nature of unknown peaks in the mass spectra. The reaction was found to proceed as expected from theory with the triazine reacting with hydrogen sulphide to form the corresponding thiadiazine. This species subsequently reacted with a second hydrogen sulphide molecule to form...... the dithiazine species, hereby confirming previously obtained results and showing the ability of the ESI-MS method for studying the scavenging reaction. The final theoretical product s-trithiane was not detected. Furthermore, fragmentation products of thiadiazine and dithiazine were detected in the solution......-oxoethyl)-methaniminium. Dithiazine fragmented to N-methyl-N-(2-oxoethyl)-methaniminium as well. The by-product from this reaction is methanedithiol, which was not detected due to its low polarity....

  11. Drikkevands optagelse af cadmium og bly fra armaturer

    DEFF Research Database (Denmark)

    Nielsen, K.

    Notatet omfatter rapporter fra to forsøgsrækker vedr. brugsvands optagelse af bly og cadmium. Den første omhandler brugsvandsarmaturers afgivelse af bly og cadmium til syntetisk brugsvand med en sammensætning svarende til en sur, blød vandtype. Forsøgene omfatter 10 armaturer og armaturdele...

  12. Cadmium-induced ectopic apoptosis in zebrafish embryos

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Po Kwok; Cheng, Shuk Han [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong)

    2003-02-01

    In this study, we tested the hypothesis that cadmium-induced developmental toxicity was mediated via ectopic occurrence of apoptosis during embryonic development. We employed confocal microscopy to acquire images of whole-mount staining of apoptotic cells in zebrafish embryo exposed to 100 {mu}M cadmium from 5 hours post fertilisation (hpf) to 28 hpf. Three-dimensional reconstruction of the images was performed and the spatial and temporal distributions of apoptotic cells in the embryos were compared. In cadmium-treated embryos with varying degrees of gross developmental malformations, significantly higher numbers of apoptotic cells were detected with this method. In order to detect the precise locations of apoptotic cells, we performed terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay in sectioned embryos. In the degenerating neural tube of cadmium-treated embryos apoptotic cells were detected, while in the healthy neural tube of the untreated controls no apoptotic cells were found. We then employed flow cytometry to investigate whether cadmium exposure would affect the dynamics of apoptosis or induce any abnormalities in cell-cycle progression. It appeared that cadmium did not induce cell-cycle arrest. The percentages of apoptotic cells did not differ in the two groups at 13, 16 or 19 hpf. At 28 hpf, however, a significantly higher percentage of apoptotic cells were found in the cadmium-treated group. Exposure to cadmium, therefore, induced ectopic apoptosis at 28 hpf without affecting the dynamics of apoptosis at earlier developmental stages. (orig.)

  13. Cadmium inhibits neurogenesis in zebrafish embryonic brain development

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Elly Suk Hen [Division of Biology, California Institute of Technology, 1200 California Boulevard, Pasadena, CA 91125 (United States); Hui, Michelle Nga Yu; Lin Chunchi [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Cheng Shukhan [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China)], E-mail: bhcheng@cityu.edu.hk

    2008-05-01

    Cadmium is a non-essential heavy metal found abundantly in the environment. Children of women exposed to cadmium during pregnancy display lower motor and perceptual abilities. High cadmium body burden in children is also related to impaired intelligence and lowered school achievement. However, little is known about the molecular and cellular basis of developmental neurotoxicity in the sensitive early life stages of animals. In this study, we explore neurological deficits caused by cadmium during early embryonic stages in zebrafish by examining regionalization of the neural tube, pattern formation and cell fate determination, commitment of proneural genes and induction of neurogenesis. We show that cadmium-treated embryos developed a smaller head with unclear boundaries between the brain subdivisions, particularly in the mid-hindbrain region. Embryos display normal anterior to posterior regionalization; however, the commitment of neural progenitor cells was affected by cadmium. We observe prominent reductions in the expression of several proneuronal genes including ngn1 in cell clusters, zash1a in the developing optic tectum, and zash1b in the telencephalon and tectum. Cadmium-treated embryos also have fewer differentiated neurons and glia in the facial sensory ganglia as indicated by decreased zn-12 expression. Also, a lower transcription level of neurogenic genes, ngn1 and neuroD, is observed in neurons. Our data suggest that cadmium-induced neurotoxicity can be caused by impaired neurogenesis, resulting in markedly reduced neuronal differentiation and axonogenesis.

  14. Epigenetic Effects of Cadmium [Abstract and Poster 2014

    Science.gov (United States)

    We have reviewed the literature on in vitro and in vivo experiments as well as human studies on cadmium to understand the epigenetic mechanisms involved in cadmium- induced toxicity and carcinogenicity. This presentation will identify gaps in our current understanding and suggest...

  15. Electrolytic indium refining from cadmium in glycerine electrolyte

    International Nuclear Information System (INIS)

    The results of investigations directed on development of electrochemical indium cleaning from cadmium in glycerine base electrolyte are presented. Optimal operational conditions, specific consumption of reactants and electric power are determined. Relationship between variation of concentration of cadmium impurity in refined metal and duration of electrolysis is revealed. The method for determination of cleaning time is proposed. Developed process was put into commercial operation

  16. Method of making a thin film cadmium telluride solar cell

    International Nuclear Information System (INIS)

    A method for making a photovoltaic cell is described comprising the steps of: (a) depositing a transparent or semi-transparent conductive window layer onto a substrate; (b) depositing a layer of cadmium telluride including phosphorus onto the window layer; (c) depositing a layer of lead telluride onto the layer of cadmium telluride; and (d) depositing a metallic electrode onto the lead telluride layer

  17. Removing cadmium from electroplating wastewater by waste saccharomyces cerevisiae

    Institute of Scientific and Technical Information of China (English)

    DAI Shu-juan; WEI De-zhou; ZHOU Dong-qin; JIA Chun-yun; WANG Yu-juan; LIU Wen-gang

    2008-01-01

    The appropriate condition and scheme of removing cadmium from electroplating wastewater were investigated by adsorption-precipitation method using waste saccharomyces cerevisiae(WSC) as sorbent. Effect factors on biosorption of cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae and precipitation process of waste saccharomyces cerevisiae after adsorbing cadmium were studied. The results show that removal rate of cadmium is over 88% after 30 min adsorbing under the condition of cadmium concentration 26 mg/L, the dosage of waste saccharomyces cerevisiae 16.25 g/L, temperature 18 ℃, pH 6.0 and precipitation time 4 h. Biosorption-precipitation method is effective to remove cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae. The SEM, infrared spectroscopy and Zeta-potential of the cells show that chemical chelating is the main adsorption form; electrostatic attraction, hydrogen bonding and van der Waals force all function in adsorption process; and ―NH2―,―C=O―,―C=O―NH―,―CH3, ―OH are the main adsorption groups.

  18. Cadmium and zinc reversibly arrest development of Artemia larvae

    Energy Technology Data Exchange (ETDEWEB)

    Bagshaw, J.C.; Rafiee, P.; Matthews, C.O.; MacRae, T.H.

    1986-08-01

    Despite the widespread distribution of heavy metals such as cadmium and zinc in the environment and their well-known cytotoxicity and embryotoxicity in mammals, comparatively little is known about their effect on aquatic organisms, particularly invertebrates. Post-gastrula and early larval development of the brine shrimp, Artemia, present some useful advantages for studies of developmental aspects of environmental toxicology. Dormant encysted gastrulae, erroneously called brine shrimp eggs, can be obtained commercially and raised in the laboratory under completely defined conditions. Following a period of post-gastrula development within the cyst, pre-nauplius larvae emerge through a crack in the cyst shell. A few hours later, free-swimming nauplius larvae hatch. Cadmium is acutely toxic to both adults and nauplius larvae of Artemia, but the reported LC50s are as high as 10 mM, depending on larval age. In this paper the authors show that pre-nauplius larvae prior to hatching are much more sensitive to cadmium than are hatched nauplius larvae. At 0.1 ..mu..m, cadmium retards development and hatching of larvae; higher concentrations block hatching almost completely and thus are lethal. However, the larvae arrested at the emergence stage survive for 24 hours or more before succumbing to the effects of cadmium, and during this period the potentially lethal effect is reversible if the larvae are placed in cadmium-free medium. The effects of zinc parallel those of cadmium, although zinc is somewhat less toxic than cadmium at equal concentrations.

  19. Cadmium Removal from Aqueous Solutions by Ground Pine Cone

    Directory of Open Access Journals (Sweden)

    H Izanloo, S Nasseri

    2005-01-01

    Full Text Available A study on the removal of cadmium ions from aqueous solutions by pine cone was conducted in batch conditions. Kinetic data and equilibrium removal isotherms were obtained. The influence of different experimental parameters such as contact time, initial concentration of cadmium, pine cone mass and particle size, and temperature on the kinetics of cadmium removal was studied. Results showed that the main parameters that played an important role in removal phenomenon were initial cadmium concentration, particle size and pine cone mass. The necessary time to reach equilibrium was between 4 and 7 hours based on the initial concentration of cadmium. The capacity of cadmium adsorption at equilibrium increased with the decrease of pine cone particle size. The capacity of cadmium adsorption at equilibrium by pine cone increased with the quantity of pine cone introduced (1–4 g/L. Temperature in the range of 20-30°C showed a restricted effect on the removal kinetics (13.56 mg/g at 20°C and a low capacity of adsorption about 11.48 mg/g at 30°C. The process followed pseudo second-order kinetics. The cadmium uptake of pine cone was quantitatively evaluated using adsorption isotherms. Results indicated that the Langmuir model gave a better fit to the experimental data in comparison with the Freundlich equation.

  20. Effect of environmental exposure to Cadmium on pregnancy outcome

    Directory of Open Access Journals (Sweden)

    F. Ramezanzadeh

    2010-04-01

    Full Text Available "n "n "nBackgrounds andObjectives:The objective of the present study was to evaluate the potential effect of environmental exposure to toxic metal (cadmium on pregnancy outcome and fetal growth."nMaterials and Methods: 330 normal pregnant women were randomly selected from vali-e-asr hospital, from July 2003 through Feb. 2005. Cadmium was measured in umbilical cord blood and mother whole blood of postpartum women without occupational exposure to metals in Tehran, Iran, using inductively coupled plasma mass spectrometry"nResult: Whole blood cadmium and cord blood cadmium ranged from 0/00 to 6/30 μg/L ,respectivly. in the group higher level of maternal blood cadmium (> 0.40 μg/L 1cm decrease was seen in neonatal birth height. (p = 0.007 There was a significant association between cadmium exposure and birth weight.Mann-whitney test showed that, maternal blood cadmium level, was significantly negatively associated with neonatal birth weight (z = -1.83, P < 0.06."nConclusion: It was concluded that environmental exposure to cadmium significantly reduces neonatal birth height.