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Sample records for alkali heavy metals

  1. Outer-core emission spectra of heavy alkali metals

    NASA Astrophysics Data System (ADS)

    Fink, R. L.; First, P. N.; Flynn, C. P.

    1988-09-01

    We report np5(n+1)s2-->np6(n+1)s emission spectra of K (n=3), Rb (n=4), and Cs (n=5), and compare emission-band characteristics through the series Na-Cs using earlier data for Na. The normalized band profiles of the different alkali metals are remarkably similar when scaled by the Fermi energy EF. However, the spin-orbit partner intensity ratios are far from the ideal value 2, reaching approximately 60 for Rb and above 65 for Cs, mainly owing to Coster-Kronig decays from higher levels. We confirm that the Mahan-Nozières-De Dominicis ``anomaly'' at EF is generally weaker in emission than in absorption. It decreases through the series to become undetectable for emission from Cs. A systematic increase of the core-hole-lifetime width occurs through the column of alkali metals from a reported estimate of 10 meV for Na to a value of 50 meV for Cs. A study of the Fermi-edge shape between 20 and 300 K reveals temperature-dependent phonon broadening in generally good agreement with theoretical predictions. Incomplete relaxation plays only a minor role in the edge processes of the heavy alkali metals. Additional Fermi-edge broadening and the shifted emission edges of surface atoms are observed for alkali-metal films 10-100 Å thick.

  2. Using fume silica as heavy metals' stabilizer for high alkali and porous MSWI baghouse ash.

    PubMed

    Huang, Wu-Jang; Huang, Hung-Shao

    2008-03-21

    In this study, we have proved that heavy metals in high porous and alkali baghouse ash could be fixed effectively by fume silica powder alone, or with the incorporation of colloidal aluminum oxide (CAO). The optimum amount is about 100g of fume silica per kilogram of baghouse ash. Results have indicated that fume silica has a better fixation efficiency of lead in high porous baghouse ash. In addition, the reaction mechanism of fume silica is also discussed.

  3. Electronic and structural ground state of heavy alkali metals at high pressure

    DOE PAGES

    Fabbris, G.; Lim, J.; Veiga, L. S. I.; ...

    2015-02-17

    Here, alkali metals display unexpected properties at high pressure, including emergence of low symmetry crystal structures, that appear to occur due to enhanced electronic correlations among the otherwise nearly-free conduction electrons. We investigate the high pressure electronic and structural ground state of K, Rb, and Cs using x-ray absorption spectroscopy and x-ray diffraction measurements together with ab initio theoretical calculations. The sequence of phase transitions under pressure observed at low temperature is similar in all three heavy alkalis except for the absence of the oC84 phase in Cs. Both the experimental and theoretical results point to pressure-enhanced localization of themore » valence electrons characterized by pseudo-gap formation near the Fermi level and strong spd hybridization. Although the crystal structures predicted to host magnetic order in K are not observed, the localization process appears to drive these alkalis closer to a strongly correlated electron state.« less

  4. Electronic and structural ground state of heavy alkali metals at high pressure

    SciTech Connect

    Fabbris, G.; Lim, J.; Veiga, L. S. I.; Haskel, D.; Schilling, J. S.

    2015-02-17

    Here, alkali metals display unexpected properties at high pressure, including emergence of low symmetry crystal structures, that appear to occur due to enhanced electronic correlations among the otherwise nearly-free conduction electrons. We investigate the high pressure electronic and structural ground state of K, Rb, and Cs using x-ray absorption spectroscopy and x-ray diffraction measurements together with ab initio theoretical calculations. The sequence of phase transitions under pressure observed at low temperature is similar in all three heavy alkalis except for the absence of the oC84 phase in Cs. Both the experimental and theoretical results point to pressure-enhanced localization of the valence electrons characterized by pseudo-gap formation near the Fermi level and strong spd hybridization. Although the crystal structures predicted to host magnetic order in K are not observed, the localization process appears to drive these alkalis closer to a strongly correlated electron state.

  5. Purification of alkali metal nitrates

    DOEpatents

    Fiorucci, Louis C.; Gregory, Kevin M.

    1985-05-14

    A process is disclosed for removing heavy metal contaminants from impure alkali metal nitrates containing them. The process comprises mixing the impure nitrates with sufficient water to form a concentrated aqueous solution of the impure nitrates, adjusting the pH of the resulting solution to within the range of between about 2 and about 7, adding sufficient reducing agent to react with heavy metal contaminants within said solution, adjusting the pH of the solution containing reducing agent to effect precipitation of heavy metal impurities and separating the solid impurities from the resulting purified aqueous solution of alkali metal nitrates. The resulting purified solution of alkali metal nitrates may be heated to evaporate water therefrom to produce purified molten alkali metal nitrate suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of alkali metal nitrates.

  6. Upgrading platform using alkali metals

    SciTech Connect

    Gordon, John Howard

    2014-09-09

    A process for removing sulfur, nitrogen or metals from an oil feedstock (such as heavy oil, bitumen, shale oil, etc.) The method involves reacting the oil feedstock with an alkali metal and a radical capping substance. The alkali metal reacts with the metal, sulfur or nitrogen content to form one or more inorganic products and the radical capping substance reacts with the carbon and hydrogen content to form a hydrocarbon phase. The inorganic products may then be separated out from the hydrocarbon phase.

  7. Alkali metal nitrate purification

    DOEpatents

    Fiorucci, Louis C.; Morgan, Michael J.

    1986-02-04

    A process is disclosed for removing contaminants from impure alkali metal nitrates containing them. The process comprises heating the impure alkali metal nitrates in solution form or molten form at a temperature and for a time sufficient to effect precipitation of solid impurities and separating the solid impurities from the resulting purified alkali metal nitrates. The resulting purified alkali metal nitrates in solution form may be heated to evaporate water therefrom to produce purified molten alkali metal nitrates suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of purified alkali metal nitrates.

  8. Alkali activation of recovered fuel-biofuel fly ash from fluidised-bed combustion: Stabilisation/solidification of heavy metals.

    PubMed

    Yliniemi, Juho; Pesonen, Janne; Tiainen, Minna; Illikainen, Mirja

    2015-09-01

    Recovered fuel-biofuel fly ash from a fluidized bed boiler was alkali-activated and granulated with a sodium-silicate solution in order to immobilise the heavy metals it contains. The effect of blast-furnace slag and metakaolin as co-binders were studied. Leaching standard EN 12457-3 was applied to evaluate the immobilisation potential. The results showed that Ba, Pb and Zn were effectively immobilised. However, there was increased leaching after alkali activation for As, Cu, Mo, Sb and V. The co-binders had minimal or even negative effect on the immobilisation. One exception was found for Cr, in which the slag decreased leaching, and one was found for Cu, in which the slag increased leaching. A sequential leaching procedure was utilized to gain a deeper understanding of the immobilisation mechanism. By using a sequential leaching procedure it is possible fractionate elements into watersoluble, acid-soluble, easily-reduced and oxidisable fractions, yielding a total 'bioavailable' amount that is potentially hazardous for the environment. It was found that the total bioavailable amount was lower following alkali activation for all heavy metals, although the water-soluble fraction was higher for some metals. Evidence from leaching tests suggests the immobilisation mechanism was chemical retention, or trapping inside the alkali activation reaction products, rather than physical retention, adsorption or precipitation as hydroxides.

  9. Formation and Reduction of Pollutants in CFBC: From Heavy Metals, Particulates, Alkali, NOx, N2O, SOx, HCl

    NASA Astrophysics Data System (ADS)

    Winter, Franz

    Due to the advantages of fluidized bed combustors a wide range of different fuels is utilized. The fuels range from anthracite, medium and low rank coals to peat, wood residues, biomass waste, sewage sludge and other sludges to plastics and municipal solid waste. Because of this wide range of fuels pollutants such as heavy metals, particulates, alkali, NO, NO2, N2O, SO2, SO3 and HCI may be formed during the fuel conversion process depending on the fuel and operating conditions.

  10. Intercalation of heavy alkali metals (K, Rb and Cs) in the bundles of single wall nanotubes

    NASA Astrophysics Data System (ADS)

    Duclaux, L.; Méténier, K.; Lauginie, P.; Salvetat, J. P.; Bonnamy, S.; Beguin, F.

    2000-11-01

    The electric-arc discharge carbon deposits (collaret) containing Single Wall Carbon Nanotubes (SWNTs) were heat treated at 1600 °C during 2 days under N2 flow in order to eliminate the Ni catalyst by sublimation, without modifications of the SWNTs ropes. Sorting this deposit by gravity enabled to obtain in the coarsest particles higher amount of SWNTs ropes than in other particle sizes. The coarser particles of the carbon deposits were reacted with the alkali metals vapor giving intercalated samples with a MC8 composition. The intercalation led to an expansion of the 2D lattice of the SWNTs so that the alkali metals were intercalated in between the tubes within the bundles. Disordered lattices were observed after intercalation of Rb and Cs. The simulations of the X-ray diffractograms of SWNTs reacted with K, gave the best fit for three K ions occupying the inter-tubes triangular cavities. The investigations by EPR, and 13C NMR, showed that doped carbon deposits are metallic.

  11. Alkali metal ionization detector

    DOEpatents

    Bauerle, James E.; Reed, William H.; Berkey, Edgar

    1978-01-01

    Variations in the conventional filament and collector electrodes of an alkali metal ionization detector, including the substitution of helical electrode configurations for either the conventional wire filament or flat plate collector; or, the substitution of a plurality of discrete filament electrodes providing an in situ capability for transferring from an operationally defective filament electrode to a previously unused filament electrode without removing the alkali metal ionization detector from the monitored environment. In particular, the helical collector arrangement which is coaxially disposed about the filament electrode, i.e. the thermal ionizer, provides an improved collection of positive ions developed by the filament electrode. The helical filament design, on the other hand, provides the advantage of an increased surface area for ionization of alkali metal-bearing species in a monitored gas environment as well as providing a relatively strong electric field for collecting the ions at the collector electrode about which the helical filament electrode is coaxially positioned. Alternatively, both the filament and collector electrodes can be helical. Furthermore, the operation of the conventional alkali metal ionization detector as a leak detector can be simplified as to cost and complexity, by operating the detector at a reduced collector potential while maintaining the sensitivity of the alkali metal ionization detector adequate for the relatively low concentration of alkali vapor and aerosol typically encountered in leak detection applications.

  12. Methods of recovering alkali metals

    DOEpatents

    Krumhansl, James L; Rigali, Mark J

    2014-03-04

    Approaches for alkali metal extraction, sequestration and recovery are described. For example, a method of recovering alkali metals includes providing a CST or CST-like (e.g., small pore zeolite) material. The alkali metal species is scavenged from the liquid mixture by the CST or CST-like material. The alkali metal species is extracted from the CST or CST-like material.

  13. Alkali metal ion battery with bimetallic electrode

    DOEpatents

    Boysen, Dane A; Bradwell, David J; Jiang, Kai; Kim, Hojong; Ortiz, Luis A; Sadoway, Donald R; Tomaszowska, Alina A; Wei, Weifeng; Wang, Kangli

    2015-04-07

    Electrochemical cells having molten electrodes having an alkali metal provide receipt and delivery of power by transporting atoms of the alkali metal between electrode environments of disparate chemical potentials through an electrochemical pathway comprising a salt of the alkali metal. The chemical potential of the alkali metal is decreased when combined with one or more non-alkali metals, thus producing a voltage between an electrode comprising the molten the alkali metal and the electrode comprising the combined alkali/non-alkali metals.

  14. Hydrothermal alkali metal recovery process

    DOEpatents

    Wolfs, Denise Y.; Clavenna, Le Roy R.; Eakman, James M.; Kalina, Theodore

    1980-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by treating them with a calcium or magnesium-containing compound in the presence of water at a temperature between about 250.degree. F. and about 700.degree. F. and in the presence of an added base to establish a pH during the treatment step that is higher than would otherwise be possible without the addition of the base. During the treating process the relatively high pH facilitates the conversion of water-insoluble alkali metal compounds in the alkali metal residues into water-soluble alkali metal constituents. The resultant aqueous solution containing water-soluble alkali metal constituents is then separated from the residue solids, which consist of the treated particles and any insoluble materials formed during the treatment step, and recycled to the gasification process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst. Preferably, the base that is added during the treatment step is an alkali metal hydroxide obtained by water washing the residue solids produced during the treatment step.

  15. Preparation of alkali metal dispersions

    NASA Technical Reports Server (NTRS)

    Rembaum, A.; Landel, R. F. (Inventor)

    1968-01-01

    A method is described for producing alkali metal dispersions of high purity. The dispersions are prepared by varying the equilibrium solubility of the alkali metal in a suitable organic solvent in the presence of aromatic hydrocarbons. The equilibrium variation is produced by temperature change. The size of the particles is controlled by controlling the rate of temperature change.

  16. PROCESS OF RECOVERING ALKALI METALS

    DOEpatents

    Wolkoff, J.

    1961-08-15

    A process is described of recovering alkali metal vapor by sorption on activated alumina, activated carbon, dehydrated zeolite, activated magnesia, or Fuller's earth preheated above the vaporization temperature of the alkali metal and subsequent desorption by heating the solvent under vacuum. (AEC)

  17. Upgrading platform using alkali metals

    DOEpatents

    Gordon, John Howard

    2017-01-17

    A method for removing sulfur, nitrogen or metals from an oil feedstock. The method involves reacting the oil feedstock with an alkali metal and a radical capping substance. The alkali metal reacts with the metal, sulfur or nitrogen content to form one or more inorganic products and the radical capping substance reacts with the carbon and hydrogen content to form a hydrocarbon phase. The inorganic products may then be separated out from the hydrocarbon phase.

  18. [Novel process utilizing alkalis assisted hydrothermal process to stabilize heavy metals both from municipal solid waste or medical waste incinerator fly ash and waste water].

    PubMed

    Wang, Lei; Jin, Jian; Li, Xiao-dong; Chi, Yong; Yan, Jian-hua

    2010-08-01

    An alkalis assisted hydrothermal process was induced to stabilize heavy metals both from municipal solid waste or medical waste incinerator fly ash and waste water. The results showed that alkalis assisted hydrothermal process removed the heavy metals effectively from the waste water, and reduced leachability of fly ash after process. The heavy metal leachabilities of fly ash studied in this paper were Mn 17,300 microg/L,Ni 1650 microg/L, Cu 2560 microg/L, Zn 189,000 microg/L, Cd 1970 microg/L, Pb 1560 microg/L for medical waste incinerator fly ash; Mn 17.2 microg/L, Ni 8.32 microg/L, Cu 235.2 microg/L, Zn 668.3 microg/L, Cd 2.81 microg/L, Pb 7200 microg/L for municipal solid waste incinerator fly ash. After hydrothermal process with experimental condition [Na2CO3 dosage (5 g Na2CO3/50 g fly ash), reaction time = 10 h, L/S ratio = 10/1], the heavy metal removal efficiencies of medical waste incinerator fly ash were 86.2%-97.3%, and 94.7%-99.6% for municipal solid waste incinerator fly ash. The leachabilities of both two kinds of fly ash were lower than that of the Chinese national limit. The mechanism of heavy metal stabilization can be concluded to the chemisorption and physically encapsulation effects of aluminosilicates during its formation, crystallization and aging process, the high pH value has some contribution to the heavy metal removal and stabilization.

  19. Apparatus enables accurate determination of alkali oxides in alkali metals

    NASA Technical Reports Server (NTRS)

    Dupraw, W. A.; Gahn, R. F.; Graab, J. W.; Maple, W. E.; Rosenblum, L.

    1966-01-01

    Evacuated apparatus determines the alkali oxide content of an alkali metal by separating the metal from the oxide by amalgamation with mercury. The apparatus prevents oxygen and moisture from inadvertently entering the system during the sampling and analytical procedure.

  20. Alkali metal and alkali earth metal gadolinium halide scintillators

    DOEpatents

    Bourret-Courchesne, Edith; Derenzo, Stephen E.; Parms, Shameka; Porter-Chapman, Yetta D.; Wiggins, Latoria K.

    2016-08-02

    The present invention provides for a composition comprising an inorganic scintillator comprising a gadolinium halide, optionally cerium-doped, having the formula A.sub.nGdX.sub.m:Ce; wherein A is nothing, an alkali metal, such as Li or Na, or an alkali earth metal, such as Ba; X is F, Br, Cl, or I; n is an integer from 1 to 2; m is an integer from 4 to 7; and the molar percent of cerium is 0% to 100%. The gadolinium halides or alkali earth metal gadolinium halides are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

  1. Adsorption of superfluid 4He films on planar heavy-alkali metals studied with the Orsay-Trento density functional

    NASA Astrophysics Data System (ADS)

    Szybisz, Leszek

    2003-04-01

    The wetting of planar surfaces of alkali metals (Cs, Rb, K, and Na) by superfluid 4He films at T=0 K is theoretically studied. Calculations have been carried out by using the Orsay-Trento nonlocal density functional and the adsorption potential of Chizmeshya-Cole-Zaremba. Surface tensions and contact angles are determined for several approximations. We find that the conclusion on the wetting of an Rb substrate is sensible to the gradient-gradient term in the functional and the softness of the He-metal interaction.

  2. Spectrum, radial wave functions, and hyperfine splittings of the Rydberg states in heavy alkali-metal atoms

    NASA Astrophysics Data System (ADS)

    Sanayei, Ali; Schopohl, Nils

    2016-07-01

    We present numerically accurate calculations of the bound-state spectrum of the highly excited valence electron in the heavy alkali-metal atoms solving the radial Schrödinger eigenvalue problem with a modern spectral collocation method that applies also for a large principal quantum number n ≫1 . As an effective single-particle potential we favor the reputable potential of Marinescu et al. [Phys. Rev. A 49, 982 (1994)], 10.1103/PhysRevA.49.982. Recent quasiclassical calculations of the quantum defect of the valence electron agree for orbital angular momentum l =0 ,1 ,2 ,... overall remarkably well with the results of the numerical calculations, but for the Rydberg states of rubidium and also cesium with l =3 this agreement is less fair. The reason for this anomaly is that in rubidium and cesium the potential acquires for l =3 deep inside the ionic core a second classical region, thus invalidating a standard Wentzel-Kramers-Brillouin (WKB) calculation with two widely spaced turning points. Comparing then our numerical solutions of the radial Schrödinger eigenvalue problem with the uniform analytic WKB approximation of Langer constructed around the remote turning point rn,j ,l (" close=")n -δ0)">+ we observe everywhere a remarkable agreement, apart from a tiny region around the inner turning point rn,j ,l (-). For s states the centrifugal barrier is absent and no inner turning point exists: rn,j ,0 (-)=0 . With the help of an ansatz proposed by Fock we obtain for the s states a second uniform analytic approximation to the radial wave function complementary to the WKB approximation of Langer, which is exact for r →0+ . From the patching condition, that is, for l =0 the Langer and Fock solutions should agree in the intermediate region 0

  3. Alkali Metal Cluster Theory.

    NASA Astrophysics Data System (ADS)

    Chen, Jian

    Available from UMI in association with The British Library. Requires signed TDF. In this thesis, we apply the tight-binding Hubbard model to alkali metal clusters with Hartree-Fock self-consistent methods and perturbation methods for the numerical calculations. We have studied the relation between the equilibrium structures and the range of the hopping matrix elements in the Hubbard Hamiltonian. The results show that the structures are not sensitive to the interaction range but are determined by the number of valence electrons each atom has. Inertia tensors are used to analyse the symmetries of the clusters. The principal axes of the clusters are determined and they are the axes of rotational symmetries of clusters if the clusters have any. The eigenvalues of inertia tensors which are the indication of the deformation of clusters are compared between our model and the ellipsoidal jellium model. The agreement is good for large clusters. At a finite temperature, the thermal motion fluctuates the structures. We defined a fluctuation function with the distance matrix of a cluster. The fluctuation has been studied with the Monte-Carlo simulation method. Our studies show that the clusters remain in the solid state when temperature is low. The small values of fluctuation functions indicates the thermal vibration of atoms around their equilibrium positions. If the temperature is high, the atoms are delocalized. The cluster melts and enters the liquid region. The cluster melting is simulated by the Monte-Carlo simulation with the fluctuation function we defined. Energy levels of clusters are calculated from the Hubbard model. Ionization potentials and magic numbers are also obtained from these energy levels. The results confirm that the Hubbard model is a good approximation for a small cluster. The excitation energy is presented by the difference between the original level and excited level, and the electron-hole interactions. We also have studied cooling of clusters

  4. Hydrothermal alkali metal catalyst recovery process

    DOEpatents

    Eakman, James M.; Clavenna, LeRoy R.

    1979-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles primarily in the form of water soluble alkali metal formates by treating the particles with a calcium or magnesium-containing compound in the presence of water at a temperature between about 250.degree. F. and about 700.degree. F. and in the presence of added carbon monoxide. During the treating process the water insoluble alkali metal compounds comprising the insoluble alkali metal residues are converted into water soluble alkali metal formates. The resultant aqueous solution containing water soluble alkali metal formates is then separated from the treated particles and any insoluble materials formed during the treatment process, and recycled to the gasification process where the alkali metal formates serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst. This process permits increased recovery of alkali metal constituents, thereby decreasing the overall cost of the gasification process by reducing the amount of makeup alkali metal compounds necessary.

  5. Upgrading of petroleum oil feedstocks using alkali metals and hydrocarbons

    DOEpatents

    Gordon, John Howard

    2014-09-09

    A method of upgrading an oil feedstock by removing heteroatoms and/or one or more heavy metals from the oil feedstock composition. This method reacts the oil feedstock with an alkali metal and an upgradant hydrocarbon. The alkali metal reacts with a portion of the heteroatoms and/or one or more heavy metals to form an inorganic phase separable from the organic oil feedstock material. The upgradant hydrocarbon bonds to the oil feedstock material and increases the number of carbon atoms in the product. This increase in the number of carbon atoms of the product increases the energy value of the resulting oil feedstock.

  6. Alkali metal/sulfur battery

    DOEpatents

    Anand, Joginder N.

    1978-01-01

    Alkali metal/sulfur batteries in which the electrolyte-separator is a relatively fragile membrane are improved by providing means for separating the molten sulfur/sulfide catholyte from contact with the membrane prior to cooling the cell to temperatures at which the catholyte will solidify. If the catholyte is permitted to solidify while in contact with the membrane, the latter may be damaged. The improvement permits such batteries to be prefilled with catholyte and shipped, at ordinary temperatures.

  7. Process for recovering alkali metals and sulfur from alkali metal sulfides and polysulfides

    DOEpatents

    Gordon, John Howard; Alvare, Javier

    2016-10-25

    Alkali metals and sulfur may be recovered from alkali monosulfide and polysulfides in an electrolytic process that utilizes an electrolytic cell having an alkali ion conductive membrane. An anolyte solution includes an alkali monosulfide, an alkali polysulfide, or a mixture thereof and a solvent that dissolves elemental sulfur. A catholyte includes molten alkali metal. Applying an electric current oxidizes sulfide and polysulfide in the anolyte compartment, causes alkali metal ions to pass through the alkali ion conductive membrane to the catholyte compartment, and reduces the alkali metal ions in the catholyte compartment. Liquid sulfur separates from the anolyte solution and may be recovered. The electrolytic cell is operated at a temperature where the formed alkali metal and sulfur are molten.

  8. Phonon spectra of alkali metals

    NASA Astrophysics Data System (ADS)

    Zeković, S.; Vukajlović, F.; Veljković, V.

    1982-10-01

    In this work we used a simple local model pseudopotential which includes screening for the phonon spectra calculations of alkali metals. The results obtained are in very good agreement with experimental data. In some branches of phonon spectra the differences between theoretical and experimental results are within 1-2%, while the maximum error is about 6%. The suggested form of the pseudopotential allows us to describe the phonon spectra of Na, K and Rb with only one, and, at the same time, a unique, parameter. In this case, the maximum disagreements from experiment are 9% for Na, 8% for K and 7% for Rb.

  9. Process for the disposal of alkali metals

    DOEpatents

    Lewis, Leroy C.

    1977-01-01

    Large quantities of alkali metals may be safely reacted for ultimate disposal by contact with a hot concentrated caustic solution. The alkali metals react with water in the caustic solution in a controlled reaction while steam dilutes the hydrogen formed by the reaction to a safe level.

  10. Method of handling radioactive alkali metal waste

    DOEpatents

    Wolson, R.D.; McPheeters, C.C.

    Radioactive alkali metal is mixed with particulate silica in a rotary drum reactor in which the alkali metal is converted to the monoxide during rotation of the reactor to produce particulate silica coated with the alkali metal monoxide suitable as a feed material to make a glass for storing radioactive material. Silica particles, the majority of which pass through a 95 mesh screen or preferably through a 200 mesh screen, are employed in this process, and the preferred weight ratio of silica to alkali metal is 7 to 1 in order to produce a feed material for the final glass product having a silica to alkali metal monoxide ratio of about 5 to 1.

  11. Method of handling radioactive alkali metal waste

    DOEpatents

    Wolson, Raymond D.; McPheeters, Charles C.

    1980-01-01

    Radioactive alkali metal is mixed with particulate silica in a rotary drum reactor in which the alkali metal is converted to the monoxide during rotation of the reactor to produce particulate silica coated with the alkali metal monoxide suitable as a feed material to make a glass for storing radioactive material. Silica particles, the majority of which pass through a 95 mesh screen or preferably through a 200 mesh screen, are employed in this process, and the preferred weight ratio of silica to alkali metal is 7 to 1 in order to produce a feed material for the final glass product having a silica to alkali metal monoxide ratio of about 5 to 1.

  12. Alkali metal for ultraviolet band-pass filter

    NASA Technical Reports Server (NTRS)

    Mardesich, Nick (Inventor); Fraschetti, George A. (Inventor); Mccann, Timothy A. (Inventor); Mayall, Sherwood D. (Inventor); Dunn, Donald E. (Inventor); Trauger, John T. (Inventor)

    1993-01-01

    An alkali metal filter having a layer of metallic bismuth deposited onto the alkali metal is provided. The metallic bismuth acts to stabilize the surface of the alkali metal to prevent substantial surface migration from occurring on the alkali metal, which may degrade optical characteristics of the filter. To this end, a layer of metallic bismuth is deposited by vapor deposition over the alkali metal to a depth of approximately 5 to 10 A. A complete alkali metal filter is described along with a method for fabricating the alkali metal filter.

  13. Alkali Metal Handling Practices at NASA MSFC

    NASA Technical Reports Server (NTRS)

    Salvail, Patrick G.; Carter, Robert R.

    2002-01-01

    NASA Marshall Space Flight Center (MSFC) is NASA s principle propulsion development center. Research and development is coordinated and carried out on not only the existing transportation systems, but also those that may be flown in the near future. Heat pipe cooled fast fission cores are among several concepts being considered for the Nuclear Systems Initiative. Marshall Space Flight Center has developed a capability to handle high-purity alkali metals for use in heat pipes or liquid metal heat transfer loops. This capability is a low budget prototype of an alkali metal handling system that would allow the production of flight qualified heat pipe modules or alkali metal loops. The processing approach used to introduce pure alkali metal into heat pipe modules and other test articles are described in this paper.

  14. Improved alkali-metal/silicate binders

    NASA Technical Reports Server (NTRS)

    Schutt, J.

    1978-01-01

    Family of inorganic binders utilizes potassium or sodium oxide/silicate dispersion and employs high mole ratio of silicon dioxide to alkali-metal binder. Binders are stable, inexpensive, extremely water resistant, and easy to apply.

  15. Alkali metal propellants for MPD thrusters

    NASA Technical Reports Server (NTRS)

    Polk, J. E.; Pivirotto, T. J.

    1991-01-01

    Experiments performed in the United States in the 1960s and early 1970s and in the Soviet Union with alkali metal-fuelled MPD thrusters indicate performance levels substantially better than those achieved with gaseous propellants. Cathode wear appears to be less in engines with alkali metal propellants also. A critical review of the available data indicates that the data are consistent and reliable. An analysis of testing and systems-level considerations shows that pumping requirements for testing are substantially decreased and reductions in tankage fraction can be expected. In addition, while care must be exercised in handling the alkali metals, it is not prohibitively difficult or hazardous. The greatest disadvantage seems to be the potential for spacecraft contamination, but there appear to be viable strategies for minimizing the impact of propellant deposition on spacecraft surfaces. Renewed examination of alkali metal-fuelled MPD thrusters for ambitious SEI missions is recommended.

  16. Heavy Metal.

    ERIC Educational Resources Information Center

    Shoemaker, W. Lee

    1998-01-01

    Discusses the advantages, both functional and economic, of using a standing-seam metal roof in both new roof installations and reroofing projects of educational facilities. Structural versus non-structural standing-seam roofs are described as are the types of insulation that can be added and roof finishes used. (GR)

  17. Maternal exposure to alkali, alkali earth, transition and other metals: Concentrations and predictors of exposure.

    PubMed

    Hinwood, A L; Stasinska, A; Callan, A C; Heyworth, J; Ramalingam, M; Boyce, M; McCafferty, P; Odland, J Ø

    2015-09-01

    Most studies of metals exposure focus on the heavy metals. There are many other metals (the transition, alkali and alkaline earth metals in particular) in common use in electronics, defense industries, emitted via combustion and which are naturally present in the environment, that have received limited attention in terms of human exposure. We analysed samples of whole blood (172), urine (173) and drinking water (172) for antimony, beryllium, bismuth, cesium, gallium, rubidium, silver, strontium, thallium, thorium and vanadium using ICPMS. In general most metals concentrations were low and below the analytical limit of detection with some high concentrations observed. Few factors examined in regression models were shown to influence biological metals concentrations and explained little of the variation. Further study is required to establish the source of metals exposures at the high end of the ranges of concentrations measured and the potential for any adverse health impacts in children.

  18. Alkali metal vapors - Laser spectroscopy and applications

    NASA Technical Reports Server (NTRS)

    Stwalley, W. C.; Koch, M. E.

    1980-01-01

    The paper examines the rapidly expanding use of lasers for spectroscopic studies of alkali metal vapors. Since the alkali metals (lithium, sodium, potassium, rubidium and cesium) are theoretically simple ('visible hydrogen'), readily ionized, and strongly interacting with laser light, they represent ideal systems for quantitative understanding of microscopic interconversion mechanisms between photon (e.g., solar or laser), chemical, electrical and thermal energy. The possible implications of such understanding for a wide variety of practical applications (sodium lamps, thermionic converters, magnetohydrodynamic devices, new lasers, 'lithium waterfall' inertial confinement fusion reactors, etc.) are also discussed.

  19. Recovery of alkali metal constituents from catalytic coal conversion residues

    DOEpatents

    Soung, W.Y.

    In a coal gasification operation (32) or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by contacting them with water or an aqueous solution to remove water-soluble alkali metal constituents and produce an aqueous solution enriched in said constituents. The aqueous solution thus produced is then contacted with carbon dioxide to precipitate silicon constituents, the pH of the resultant solution is increased, preferably to a value in the range between about 12.5 and about 15.0, and the solution of increased pH is evaporated to increase the alkali metal concentration. The concentrated aqueous solution is then recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

  20. Salts of alkali metal anions and process of preparing same

    DOEpatents

    Dye, James L.; Ceraso, Joseph M.; Tehan, Frederick J.; Lok, Mei Tak

    1978-01-01

    Compounds of alkali metal anion salts of alkali metal cations in bicyclic polyoxadiamines are disclosed. The salts are prepared by contacting an excess of alkali metal with an alkali metal dissolving solution consisting of a bicyclic polyoxadiamine in a suitable solvent, and recovered by precipitation. The salts have a gold-color crystalline appearance and are stable in a vacuum at -10.degree. C. and below.

  1. Cohesive Energy of the Alkali Metals.

    ERIC Educational Resources Information Center

    Poole, R. T.

    1980-01-01

    Describes a method, considered appropriate for presentation to undergraduate students in materials science and related courses, for the calculation of cohesive energies of the alkali metals. Uses a description based on the free electron model and gives results to within 0.1 eV of the experimental values. (Author/GS)

  2. 40 CFR 721.4740 - Alkali metal nitrites.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in...

  3. 40 CFR 721.4660 - Alcohol, alkali metal salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alcohol, alkali metal salt. 721.4660... Substances § 721.4660 Alcohol, alkali metal salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as alcohol, alkali metal salt (PMN P-91-151)...

  4. 40 CFR 721.4660 - Alcohol, alkali metal salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alcohol, alkali metal salt. 721.4660... Substances § 721.4660 Alcohol, alkali metal salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as alcohol, alkali metal salt (PMN P-91-151)...

  5. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for...

  6. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for...

  7. 40 CFR 721.4740 - Alkali metal nitrites.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in...

  8. 40 CFR 721.4660 - Alcohol, alkali metal salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alcohol, alkali metal salt. 721.4660... Substances § 721.4660 Alcohol, alkali metal salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as alcohol, alkali metal salt (PMN P-91-151)...

  9. 40 CFR 721.4740 - Alkali metal nitrites.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in...

  10. 40 CFR 721.4740 - Alkali metal nitrites.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in...

  11. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for...

  12. 40 CFR 721.4660 - Alcohol, alkali metal salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alcohol, alkali metal salt. 721.4660... Substances § 721.4660 Alcohol, alkali metal salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as alcohol, alkali metal salt (PMN P-91-151)...

  13. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for...

  14. 40 CFR 721.4740 - Alkali metal nitrites.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in...

  15. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for...

  16. 40 CFR 721.4660 - Alcohol, alkali metal salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alcohol, alkali metal salt. 721.4660... Substances § 721.4660 Alcohol, alkali metal salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as alcohol, alkali metal salt (PMN P-91-151)...

  17. Removal of Retired Alkali Metal Test Systems

    SciTech Connect

    Brehm, W. F.; Church, W. R.; Biglin, J. W.

    2003-02-26

    This paper describes the successful effort to remove alkali metals, alkali metal residues, and piping and structures from retired non-radioactive test systems on the Hanford Site. These test systems were used between 1965 and 1982 to support the Fast Flux Test Facility and the Liquid Metal Fast Breeder Reactor Program. A considerable volume of sodium and sodium-potassium alloy (NaK) was successfully recycled to the commercial sector; structural material and electrical material such as wiring was also recycled. Innovative techniques were used to safely remove NaK and its residues from a test system that could not be gravity-drained. The work was done safely, with no environmental issues or significant schedule delays.

  18. Alkali metal recovery from carbonaceous material conversion process

    DOEpatents

    Sharp, David W.; Clavenna, LeRoy R.; Gorbaty, Martin L.; Tsou, Joe M.

    1980-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced in the gasifier or similar reaction zone, alkali metal constitutents are recovered from the particles by withdrawing and passing the particles from the reaction zone to an alkali metal recovery zone in the substantial absence of molecular oxygen and treating the particles in the recovery zone with water or an aqueous solution in the substantial absence of molecular oxygen. The solution formed by treating the particles in the recovery zone will contain water-soluble alkali metal constituents and is recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst. Preventing contact of the particles with oxygen as they are withdrawn from the reaction zone and during treatment in the recovery zone avoids the formation of undesirable alkali metal constituents in the aqueous solution produced in the recovery zone and insures maximum recovery of water-soluble alkali metal constituents from the alkali metal residues.

  19. The behaviour of alkali metals in biomass conversion systems

    SciTech Connect

    Hald, P.

    1995-12-31

    Alkali metals present in biomass contribute to problems as agglomeration, deposition and corrosion. In order to reduce the problems. It is of interest to describe the behavior of alkali metals in the conversion systems. Useful tools for die description are equilibrium calculations combined with measurements of gaseous alkali metal and analyses of solid materials. A comprehensive equilibrium study has been conducted and the results organized in tables, showing which alkali metal components can be present, dependent on the temperature and the ratios alkali metal to sulphur and alkali metal to chlorine. The tables presented can be used as a catalogue, giving easy access to equilibrium results. A sampling method for die measurement of gaseous alkali metal is described and the sampling efficiency is given. The developed tools are demonstrated for a straw gasifier and a fluidized bed combustor using a coal/straw mixture as a fuel.

  20. Alkali metal protective garment and composite material

    DOEpatents

    Ballif, III, John L.; Yuan, Wei W.

    1980-01-01

    A protective garment and composite material providing satisfactory heat resistance and physical protection for articles and personnel exposed to hot molten alkali metals, such as sodium. Physical protection is provided by a continuous layer of nickel foil. Heat resistance is provided by an underlying backing layer of thermal insulation. Overlying outer layers of fireproof woven ceramic fibers are used to protect the foil during storage and handling.

  1. Alkali Metal Heat Pipe Life Issues

    SciTech Connect

    Reid, Robert S.

    2004-07-01

    One approach to fission power system design uses alkali metal heat pipes for the core primary heat-transfer system. Heat pipes may also be used as radiator elements or auxiliary thermal control elements. This synopsis characterizes long-life core heat pipes. References are included where information that is more detailed can be found. Specifics shown here are for demonstration purposes and do not necessarily reflect current Nasa Project Prometheus point designs. (author)

  2. Alkali Metal Heat Pipe Life Issues

    NASA Technical Reports Server (NTRS)

    Reid, Robert S.

    2004-01-01

    One approach to space fission power system design is predicated on the use of alkali metal heat pipes, either as radiator elements, thermal management components, or as part of the core primary heat-transfer system. This synopsis characterizes long-life core heat pipes. References are included where more detailed information can be found. Specifics shown here are for demonstrational purposes and do not necessarily reflect current Project Prometheus point designs.

  3. Method for the safe disposal of alkali metal

    DOEpatents

    Johnson, Terry R.

    1977-01-01

    Alkali metals such as those employed in liquid metal coolant systems can be safely reacted to form hydroxides by first dissolving the alkali metal in relatively inert metals such as lead or bismuth. The alloy thus formed is contacted with a molten salt including the alkali metal hydroxide and possibly the alkali metal carbonate in the presence of oxygen. This oxidizes the alkali metal to an oxide which is soluble within the molten salt. The salt is separated and contacted with steam or steam-CO.sub.2 mixture to convert the alkali metal oxide to the hydroxide. These reactions can be conducted with minimal hydrogen evolution and with the heat of reaction distributed between the several reaction steps.

  4. Electrochemical devices utilizing molten alkali metal electrode-reactant

    DOEpatents

    Hitchcock, David C.; Mailhe, Catherine C.; De Jonghe, Lutgard C.

    1986-01-01

    Electrochemical cells are provided with a reactive metal to reduce the oxide of the alkali metal electrode-reactant. Cells employing a molten alkali metal electrode, e.g., sodium, in contact with a ceramic electrolyte, which is a conductor of the ions of the alkali metal forming the electrode, exhibit a lower resistance when a reactive metal, e.g., vanadium, is allowed to react with and reduce the alkali metal oxide. Such cells exhibit less degradation of the electrolyte and of the glass seals often used to joining the electrolyte to the other components of the cell under cycling conditions.

  5. Electrochemical devices utilizing molten alkali metal electrode-reactant

    DOEpatents

    Hitchcock, D.C.; Mailhe, C.C.; De Jonghe, L.C.

    1985-07-10

    Electrochemical cells are provided with a reactive metal to reduce the oxide of the alkali metal electrode-reactant. Cells employing a molten alkali metal electrode, e.g., sodium, in contact with a ceramic electrolyte, which is a conductor of the ions of the alkali metal forming the electrode, exhibit a lower resistance when a reactive metal, e.g., vanadium, is allowed to react with and reduce the alkali metal oxide. Such cells exhibit less degradation of the electrolyte and of the glass seals often used to joining the electrolyte to the other components of the cell under cycling conditions.

  6. Integrated oil production and upgrading using molten alkali metal

    DOEpatents

    Gordon, John Howard

    2016-10-04

    A method that combines the oil retorting process (or other process needed to obtain/extract heavy oil or bitumen) with the process for upgrading these materials using sodium or other alkali metals. Specifically, the shale gas or other gases that are obtained from the retorting/extraction process may be introduced into the upgrading reactor and used to upgrade the oil feedstock. Also, the solid materials obtained from the reactor may be used as a fuel source, thereby providing the heat necessary for the retorting/extraction process. Other forms of integration are also disclosed.

  7. Vibrations of alkali metal overlayers on metal surfaces

    NASA Astrophysics Data System (ADS)

    Rusina, G. G.; Eremeev, S. V.; Echenique, P. M.; Benedek, G.; Borisova, S. D.; Chulkov, E. V.

    2008-06-01

    We review the current progress in the understanding of vibrations of alkalis adsorbed on metal surfaces. The analysis of alkali vibrations was made on the basis of available theoretical and experimental results. We also include in this discussion our recent calculations of vibrations in K/Pt(111) and Li(Na)/Cu(001) systems. The dependence of alkali adlayer localized modes on atomic mass, adsorption position and coverage as well as the dependence of vertical vibration frequency on the substrate orientation is discussed. The square root of atomic mass dependence of the vertical vibration energy has been confirmed by using computational data for alkalis on the Al(111) and Cu(001) substrates. We have confirmed that in a wide range of submonolayer coverages the stretch mode energy remains nearly constant while the energy of in-plane polarized modes increases with the increase of alkali coverage. It was shown that the spectrum of both stretch and in-plane vibrations can be very sensitive to the adsorption position of alkali atoms and substrate orientation.

  8. Cathode architectures for alkali metal / oxygen batteries

    DOEpatents

    Visco, Steven J; Nimon, Vitaliy; De Jonghe, Lutgard C; Volfkovich, Yury; Bograchev, Daniil

    2015-01-13

    Electrochemical energy storage devices, such as alkali metal-oxygen battery cells (e.g., non-aqueous lithium-air cells), have a cathode architecture with a porous structure and pore composition that is tailored to improve cell performance, especially as it pertains to one or more of the discharge/charge rate, cycle life, and delivered ampere-hour capacity. A porous cathode architecture having a pore volume that is derived from pores of varying radii wherein the pore size distribution is tailored as a function of the architecture thickness is one way to achieve one or more of the aforementioned cell performance improvements.

  9. Electrodes For Alkali-Metal Thermoelectric Converters

    NASA Technical Reports Server (NTRS)

    Williams, Roger M.; Wheeler, Bob L.; Jeffries-Nakamura, Barbara; Lamb, James L.; Bankston, C. Perry; Cole, Terry

    1989-01-01

    Combination of thin, porous electrode and overlying collector grid reduces internal resistance of alkali-metal thermoelectric converter cell. Low resistance of new electrode and grid boosts power density nearly to 1 W/cm2 of electrode area at typical operating temperatures of 1,000 to 1,300 K. Conductive grid encircles electrode film on alumina tube. Bus wire runs along tube to collect electrical current from grid. Such converters used to transform solar, nuclear, and waste heat into electric power.

  10. Superconductivity in alkali metal intercalated iron selenides

    NASA Astrophysics Data System (ADS)

    Krzton-Maziopa, A.; Svitlyk, V.; Pomjakushina, E.; Puzniak, R.; Conder, K.

    2016-07-01

    Alkali metal intercalated iron selenide superconductors A x Fe2-y Se2 (where A  =  K, Rb, Cs, Tl/K, and Tl/Rb) are characterized by several unique properties, which were not revealed in other superconducting materials. The compounds crystallize in overall simple layered structure with FeSe layers intercalated with alkali metal. The structure turned out to be pretty complex as the existing Fe-vacancies order below ~550 K, which further leads to an antiferromagnetic ordering with Néel temperature fairly above room temperature. At even lower temperatures a phase separation is observed. While one of these phases stays magnetic down to the lowest temperatures the second is becoming superconducting below ~30 K. All these effects give rise to complex relationships between the structure, magnetism and superconductivity. In particular the iron vacancy ordering, linked with a long-range magnetic order and a mesoscopic phase separation, is assumed to be an intrinsic property of the system. Since the discovery of superconductivity in those compounds in 2010 they were investigated very extensively. Results of the studies conducted using a variety of experimental techniques and performed during the last five years were published in hundreds of reports. The present paper reviews scientific work concerning methods of synthesis and crystal growth, structural and superconducting properties as well as pressure investigations.

  11. Heat pipes containing alkali metal working fluid

    NASA Technical Reports Server (NTRS)

    Morris, J. F. (Inventor)

    1981-01-01

    A technique for improving high temperature evaporation-condensation heat-transfer devices which have important and unique advantage in terrestrial and space energy processing is described. The device is in the form of a heat pipe comprising a sealed container or envelope which contains a capillary wick. The temperature of one end of the heat pipe is raised by the input of heat from an external heat source which is extremely hot and corrosive. A working fluid of a corrosive alkali metal, such as lithium, sodium, or potassium transfers this heat to a heat receiver remote from the heat source. The container and wick are fabricated from a superalloy containing a small percentage of a corrosion inhibiting or gettering element. Lanthanum, scandium, yttrium, thorium, and hafnium are utilized as the alloying metal.

  12. Device and method for upgrading petroleum feedstocks and petroleum refinery streams using an alkali metal conductive membrane

    DOEpatents

    Gordon, John Howard; Alvare, Javier

    2016-09-13

    A reactor has two chambers, namely an oil feedstock chamber and a source chamber. An ion separator separates the oil feedstock chamber from the source chamber, wherein the ion separator allows alkali metal ions to pass from the source chamber, through the ion separator, and into the oil feedstock chamber. A cathode is at least partially housed within the oil feedstock chamber and an anode is at least partially housed within the source chamber. A quantity of an oil feedstock is within the oil feedstock chamber, the oil feedstock comprising at least one carbon atom and a heteroatom and/or one or more heavy metals, the oil feedstock further comprising naphthenic acid. When the alkali metal ion enters the oil feedstock chamber, the alkali metal reacts with the heteroatom, the heavy metals and/or the naphthenic acid, wherein the reaction with the alkali metal forms inorganic products.

  13. COMPLEX FLUORIDES OF PLUTONIUM AND AN ALKALI METAL

    DOEpatents

    Seaborg, G.T.

    1960-08-01

    A method is given for precipitating alkali metal plutonium fluorides. such as KPuF/sub 5/, KPu/sub 2/F/sub 9/, NaPuF/sub 5/, and RbPuF/sub 5/, from an aqueous plutonium(IV) solution by adding hydrogen fluoride and alkali-metal- fluoride.

  14. Self-discharge in bimetallic cells containing alkali metal

    NASA Technical Reports Server (NTRS)

    Foster, M. S.; Hesson, J. C.; Shimotake, H.

    1969-01-01

    Theoretical analysis of thermally regenerative bimetallic cells with alkali metal anodes shows a relation between the current drawn and the rate of discharge under open-circuit conditions. The self-discharge rate of the cell is due to the dissolution and ionization of alkali metal atoms in the fused-salt electrolyte

  15. Recovery of alkali metal constituents from catalytic coal conversion residues

    DOEpatents

    Soung, Wen Y.

    1984-01-01

    In a coal gasification operation (32) or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by contacting them (46, 53, 61, 69) with water or an aqueous solution to remove water-soluble alkali metal constituents and produce an aqueous solution enriched in said constituents. The aqueous solution thus produced is then contacted with carbon dioxide (63) to precipitate silicon constituents, the pH of the resultant solution is increased (81), preferably to a value in the range between about 12.5 and about 15.0, and the solution of increased pH is evaporated (84) to increase the alkali metal concentration. The concentrated aqueous solution is then recycled to the conversion process (86, 18, 17) where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

  16. Electrochemical cell utilizing molten alkali metal electrode-reactant

    DOEpatents

    Virkar, Anil V.; Miller, Gerald R.

    1983-11-04

    An improved electrochemical cell comprising an additive-modified molten alkali metal electrode-reactant and/or electrolyte is disclosed. Various electrochemical cells employing a molten alkali metal, e.g., sodium, electrode in contact with a cationically conductive ceramic membrane experience a lower resistance and a lower temperature coefficient of resistance whenever small amounts of selenium are present at the interface of the electrolyte and the molten alkali metal. Further, cells having small amounts of selenium present at the electrolyte-molten metal interface exhibit less degradation of the electrolyte under long term cycling conditions.

  17. Alkali metal-refractory metal biphase electrode for AMTEC

    NASA Technical Reports Server (NTRS)

    Williams, Roger M. (Inventor); Bankston, Clyde P. (Inventor); Cole, Terry (Inventor); Khanna, Satish K. (Inventor); Jeffries-Nakamura, Barbara (Inventor); Wheeler, Bob L. (Inventor)

    1989-01-01

    An electrode having increased output with slower degradation is formed of a film applied to a beta-alumina solid electrolyte (BASE). The film comprises a refractory first metal M.sup.1 such as a platinum group metal, suitably platinum or rhodium, capable of forming a liquid or a strong surface adsorption phase with sodium at the operating temperature of an alkali metal thermoelectric converter (AMTEC) and a second refractory metal insoluble in sodium or the NaM.sup.1 liquid phase such as a Group IVB, VB or VIB metal, suitably tungsten, molybdenum, tantalum or niobium. The liquid phase or surface film provides fast transport through the electrode while the insoluble refractory metal provides a structural matrix for the electrode during operation. A trilayer structure that is stable and not subject to deadhesion comprises a first, thin layer of tungsten, an intermediate co-deposited layer of tungsten-platinum and a thin surface layer of platinum.

  18. Superconductivity in alkali-metal-doped picene.

    PubMed

    Mitsuhashi, Ryoji; Suzuki, Yuta; Yamanari, Yusuke; Mitamura, Hiroki; Kambe, Takashi; Ikeda, Naoshi; Okamoto, Hideki; Fujiwara, Akihiko; Yamaji, Minoru; Kawasaki, Naoko; Maniwa, Yutaka; Kubozono, Yoshihiro

    2010-03-04

    Efforts to identify and develop new superconducting materials continue apace, motivated by both fundamental science and the prospects for application. For example, several new superconducting material systems have been developed in the recent past, including calcium-intercalated graphite compounds, boron-doped diamond and-most prominently-iron arsenides such as LaO(1-x)F(x)FeAs (ref. 3). In the case of organic superconductors, however, no new material system with a high superconducting transition temperature (T(c)) has been discovered in the past decade. Here we report that intercalating an alkali metal into picene, a wide-bandgap semiconducting solid hydrocarbon, produces metallic behaviour and superconductivity. Solid potassium-intercalated picene (K(x)picene) shows T(c) values of 7 K and 18 K, depending on the metal content. The drop of magnetization in K(x)picene solids at the transition temperature is sharp (<2 K), similar to the behaviour of Ca-intercalated graphite. The T(c) of 18 K is comparable to that of K-intercalated C(60) (ref. 4). This discovery of superconductivity in K(x)picene shows that organic hydrocarbons are promising candidates for improved T(c) values.

  19. Controlled in-situ dissolution of an alkali metal

    DOEpatents

    Jones, Jeffrey Donald; Dooley, Kirk John; Tolman, David Donald

    2012-09-11

    A method for the controllable dissolution of one or more alkali metals from a vessel containing a one or more alkali metals and/or one or more partially passivated alkali metals. The vessel preferably comprising a sodium, NaK or other alkali metal-cooled nuclear reactor that has been used. The alkali metal, preferably sodium, potassium or a combination thereof, in the vessel is exposed to a treatment liquid, preferably an acidic liquid, more preferably citric acid. Preferably, the treatment liquid is maintained in continuous motion relative to any surface of unreacted alkali metal with which the treatment liquid is in contact. The treatment liquid is preferably pumped into the vessel containing the one or more alkali metals and the resulting fluid is extracted and optionally further processed. Preferably, the resulting off-gases are processed by an off-gas treatment system and the resulting liquids are processed by a liquid disposal system. In one preferred embodiment, an inert gas is pumped into the vessel along with the treatment liquid.

  20. (abstract) Fundamental Mechanisms of Electrode Kinetics and Alkali Metal Atom Transport at the Alkali Beta'-Alumina/Porous Electrode/Alkali Metal Vapor Three Phase Boundary

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Jeffries-Nakamura, B.; Ryan, M. A.; Underwood, M. L.; O'Connor, D.; Kisor, A.; Kikkert, S. K.

    1993-01-01

    The mechanisms of electrode kinetics and mass transport of alkali metal oxidation and alkali metal cation reduction at the solid electrolyte/porous electrode boundary as well as alkali metal transport through porous metal electrodes has important applications in optimizing device performance in alkali metal thermal to electric converter (AMTEC) cells which are high temperature, high current density electrochemical cells. Basic studies of these processes also affords the opportunity to investigate a very basic electrochemical reaction over a wide range of conditions; and a variety of mass transport modes at high temperatures via electrochemical techniques. The temperature range of these investigations covers 700K to 1240K; the alkali metal vapor pressures range from about 10(sup -2) to 10(sup 2) Pa; and electrodes studied have included Mo, W, Mo/Na(sub 2)MoO(sub 4), W/Na(sub 2)WO(sub 4), WPt(sub x), and WRh(sub x) (1.0 < x < 6.0 ) with Na at Na-beta'-alumina, and Mo with K at K-beta'-alumina. Both liquid metal/solid electrolyte/alkali metal vapor and alkali metal vapor/solid electrolyte/vapor cells have been used to characterize the reaction and transport processes. We have previously reported evidence of ionic, free molecular flow, and surface transport of sodium in several types of AMTEC electrodes.

  1. Alkali cation specific adsorption onto fcc(111) transition metal electrodes.

    PubMed

    Mills, J N; McCrum, I T; Janik, M J

    2014-07-21

    The presence of alkali cations in electrolyte solutions is known to impact the rate of electrocatalytic reactions, though the mechanism of such impact is not conclusively determined. We use density functional theory (DFT) to examine the specific adsorption of alkali cations to fcc(111) electrode surfaces, as specific adsorption may block catalyst sites or otherwise impact surface catalytic chemistry. Solvation of the cation-metal surface structure was investigated using explicit water models. Computed equilibrium potentials for alkali cation adsorption suggest that alkali and alkaline earth cations will specifically adsorb onto Pt(111) and Pd(111) surfaces in the potential range of hydrogen oxidation and hydrogen evolution catalysis in alkaline solutions.

  2. The 4843 Alkali Metal Storage Facility Closure Plan

    SciTech Connect

    Not Available

    1991-06-01

    The 4843 AMSF has been used primarily to provide a centralized building to receive and store dangerous and mixed alkali metal waste, including sodium and lithium, which has been generated at the Fast Flux Test Facility and at various other Hanford Site operations that used alkali metals. Most of the dangerous and mixed alkali metal waste received consists of retired equipment from liquid sodium processes. The unit continues to store material. In general, only solid alkali metal waste that is water reactive is stored at the 4843 AMSF. The 4843 AMSF will be closed in a manner consistent with Ecology guidelines and regulations (WAC 173-303-610). The general closure procedure is detailed as follows.

  3. Method for intercalating alkali metal ions into carbon electrodes

    DOEpatents

    Doeff, M.M.; Ma, Y.; Visco, S.J.; DeJonghe, L.

    1995-08-22

    A low cost, relatively flexible, carbon electrode for use in a secondary battery is described. A method is provided for producing same, including intercalating alkali metal salts such as sodium and lithium into carbon.

  4. Method for intercalating alkali metal ions into carbon electrodes

    DOEpatents

    Doeff, Marca M.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard

    1995-01-01

    A low cost, relatively flexible, carbon electrode for use in a secondary battery is described. A method is provided for producing same, including intercalating alkali metal salts such as sodium and lithium into carbon.

  5. Hall Determination of Atomic Radii of Alkali Metals

    ERIC Educational Resources Information Center

    Houari, Ahmed

    2008-01-01

    I will propose here an alternative method for determining atomic radii of alkali metals based on the Hall measurements of their free electron densities and the knowledge of their crystal structure. (Contains 2 figures.)

  6. Ternary alkali-metal and transition metal or metalloid acetylides as alkali-metal intercalation electrodes for batteries

    SciTech Connect

    Nemeth, Karoly; Srajer, George; Harkay, Katherine C; Terdik, Joseph Z

    2015-02-10

    Novel intercalation electrode materials including ternary acetylides of chemical formula: A.sub.nMC.sub.2 where A is alkali or alkaline-earth element; M is transition metal or metalloid element; C.sub.2 is reference to the acetylide ion; n is an integer that is 0, 1, 2, 3 or 4 when A is alkali element and 0, 1, or 2 when A is alkaline-earth element. The alkali elements are Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). The alkaline-earth elements are Berilium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). M is a transition metal that is any element in groups 3 through 12 inclusive on the Periodic Table of Elements (elements 21 (Sc) to element 30 (Zn)). In another exemplary embodiment, M is a metalloid element.

  7. Electrochemical cell having an alkali-metal-nitrate electrode

    DOEpatents

    Roche, M.F.; Preto, S.K.

    1982-06-04

    A power-producing secondary electrochemical cell includes a molten alkali metal as the negative-electrode material and a molten-nitrate salt as the positive-electrode material. The molten material in the respective electrodes are separated by a solid barrier of alkali-metal-ion conducting material. A typical cell includes active materials of molten sodium separated from molten sodium nitrate and other nitrates in mixture by a layer of sodium ..beta..'' alumina.

  8. Rock Degradation by Alkali Metals: A Possible Lunar Erosion Mechanism.

    PubMed

    Naughton, J J; Barnes, I L; Hammond, D A

    1965-08-06

    When rocks melt under ultrahigh-vacuum conditions, their alkali components volatilize as metals. These metal vapors act to comminute polycrystalline rocks to their component minerals. The resultant powder is porous and loosely packed and its characteristics may be compatible with the lunar surface as revealed by the Ranger photographs. If meteorite impact or lunar volcanism has produced vaporization or areas of molten lava, alkali erosion may have given dust of this character in adjacent solid areas.

  9. Bioinorganic Chemistry of the Alkali Metal Ions.

    PubMed

    Kim, Youngsam; Nguyen, Thuy-Tien T; Churchill, David G

    2016-01-01

    The common Group 1 alkali metals are indeed ubiquitous on earth, in the oceans and in biological systems. In this introductory chapter, concepts involving aqueous chemistry and aspects of general coordination chemistry and oxygen atom donor chemistry are introduced. Also, there are nuclear isotopes of importance. A general discussion of Group 1 begins from the prevalence of the ions, and from a comparison of their ionic radii and ionization energies. While oxygen and water molecule binding have the most relevance to biology and in forming a detailed understanding between the elements, there is a wide range of basic chemistry that is potentially important, especially with respect to biological chelation and synthetic multi-dentate ligand design. The elements are widely distributed in life forms, in the terrestrial environment and in the oceans. The details about the workings in animal, as well as plant life are presented in this volume. Important biometallic aspects of human health and medicine are introduced as well. Seeing as the elements are widely present in biology, various particular endogenous molecules and enzymatic systems can be studied. Sodium and potassium are by far the most important and central elements for consideration. Aspects of lithium, rubidium, cesium and francium chemistry are also included; they help in making important comparisons related to the coordination chemistry of Na(+) and K(+). Physical methods are also introduced.

  10. Alkali metal yttrium neo-pentoxide double alkoxide precursors to alkali metal yttrium oxide nanomaterials

    DOE PAGES

    Boyle, Timothy J.; Neville, Michael L.; Sears, Jeremiah Matthew; ...

    2016-03-15

    In this study, a series of alkali metal yttrium neo-pentoxide ([AY(ONep)4]) compounds were developed as precursors to alkali yttrium oxide (AYO2) nanomaterials. The reaction of yttrium amide ([Y(NR2)3] where R=Si(CH3)3) with four equivalents of H-ONep followed by addition of [A(NR2)] (A=Li, Na, K) or Ao (Ao=Rb, Cs) led to the formation of a complex series of AnY(ONep)3+n species, crystallographically identified as [Y2Li3(μ3-ONep)(μ3-HONep)(μ-ONep)5(ONep)3(HONep)2] (1), [YNa2(μ3-ONep)4(ONep)]2 (2), {[Y2K3(μ3-ONep)3(μ-ONep)4(ONep)2(ηξ-tol)2][Y4K2(μ4-O)(μ3-ONep)8(ONep)4]•ηx-tol]} (3), [Y4K2(μ4-O)(μ3-ONep)8(ONep)4] (3a), [Y2Rb3(μ4-ONep)3(μ-ONep)6] (4), and [Y2Cs4(μ6-O)(μ3-ONep)6(μ3-HONep)2(ONep)2(ηx-tol)4]•tol (5). Compounds 1–5 were investigated as single source precursors to AYOx nanomaterials following solvothermal routes (pyridine, 185 °C for 24h). The final products after thermal processing weremore » found by powder X-ray diffraction experiments to be Y2O3 with variable sized particles based on transmission electron diffraction. Energy dispersive X-ray spectroscopy studies indicated that the heavier alkali metal species were present in the isolated nanomaterials.« less

  11. On-chip fabrication of alkali-metal vapor cells utilizing an alkali-metal source tablet

    NASA Astrophysics Data System (ADS)

    Tsujimoto, K.; Ban, K.; Hirai, Y.; Sugano, K.; Tsuchiya, T.; Mizutani, N.; Tabata, O.

    2013-11-01

    We describe a novel on-chip microfabrication technique for the alkali-metal vapor cell of an optically pumped atomic magnetometer (OPAM), utilizing an alkali-metal source tablet (AMST). The newly proposed AMST is a millimeter-sized piece of porous alumina whose considerable surface area holds deposited alkali-metal chloride (KCl) and barium azide (BaN6), source materials that effectively produce alkali-metal vapor at less than 400 °C. Our experiments indicated that the most effective pore size of the AMST is between 60 and 170 µm. The thickness of an insulating glass spacer holding the AMST was designed to confine generated alkali metal to the interior of the vapor cell during its production, and an integrated silicon heater was designed to seal the device using a glass frit, melted at an optimum temperature range of 460-490 °C that was determined by finite element method thermal simulation. The proposed design and AMST were used to successfully fabricate a K cell that was then operated as an OPAM with a measured sensitivity of 50 pT. These results demonstrate that the proposed concept for on-chip microfabrication of alkali-metal vapor cells may lead to effective replacement of conventional glassworking approaches.

  12. Superconductivity at 5 K in alkali-metal-doped phenanthrene.

    PubMed

    Wang, X F; Liu, R H; Gui, Z; Xie, Y L; Yan, Y J; Ying, J J; Luo, X G; Chen, X H

    2011-10-18

    Organic superconductors have π-molecular orbitals, from which electrons can become delocalized, giving rise to metallic conductivity due to orbital overlap between adjacent molecules. Here we report the discovery of superconductivity at a transition temperature (T(c)) of ~5 K in alkali-metal-doped phenanthrene. A 1-GPa pressure leads to a 20% increase of T(c), suggesting that alkali-metal-doped phenanthrene shows unconventional superconductivity. Raman spectra indicate that alkali-metal doping injects charge into the system to realize the superconductivity. The discovery of superconductivity in A(3)phenanthrene (where A can be either K or Rb) produces a novel broad class of superconductors consisting of fused hydrocarbon benzene rings with π-electron networks. An increase of T(c) with increasing number of benzene rings from three to five suggests that organic hydrocarbons with long chains of benzene rings are potential superconductors with high T(c).

  13. Alkali Metal/Salt Thermal-Energy-Storage Systems

    NASA Technical Reports Server (NTRS)

    Phillips, Wayne W.; Stearns, John W.

    1987-01-01

    Proposed thermal-energy-storage system based on mixture of alkali metal and one of its halide salts; metal and salt form slurry of two immiscible melts. Use of slurry expected to prevent incrustations of solidified salts on heat-transfer surfaces that occur where salts alone used. Since incrustations impede heat transfer, system performance improved. In system, charging heat-exchanger surface immersed in lower liquid, rich in halide-salt, phase-charge material. Discharging heat exchanger surface immersed in upper liquid, rich in alkali metal.

  14. Disorders of heavy metals.

    PubMed

    Woimant, France; Trocello, Jean-Marc

    2014-01-01

    Heavy metals and trace elements play an important role in relation to the physiology and pathology of the nervous system. Neurologic diseases related to disorders of metabolism of copper and iron are reviewed. Copper disorders are divided into two classes: ATP7A- or ATP7B-related inherited copper transport disorders (Menkes disease, occipital horn syndrome, ATP7A-related distal motor neuropathy, and Wilson disease) and acquired diseases associated with copper deficiency or copper excess. Iron brain disorders are divided into genetic neurodegeneration with brain iron accumulation (NBIA, neuroferritinopathy, and aceruloplasminemia), genetic systemic iron accumulation with neurologic features (hemochromatosis), and acquired diseases associated with iron excess (superficial siderosis) or iron deficiency (restless leg syndrome). The main features of cadmium, lead, aluminum, mercury, and manganese toxicity are summarized.

  15. Failure Engineered Heavy Metal Penetrators

    DTIC Science & Technology

    1992-12-01

    ARMY RESEARCH LABORATORY Failure Engineered Heavy Metal Penetrators, Phase I, SBIR ARL-CR-5· R. Cavalieri, W. Tiarn, and D. Nicholson prepared...REPORT DATE S. REPORT TYPE AND DATES COVERED December 1992 Final Report-1/1/92 - 7/31/92 4. TITLE AND SUBTITLE FAILURE ENGINEERED HEAVY METAL PENETRATORS

  16. Lithium and Sodium Resistance of Alkali Metal Vapor Resistant Glasses

    NASA Astrophysics Data System (ADS)

    Kishinevski, Anatoly; Hall, Matthew

    2014-05-01

    A common challenge in atomic physics is that of containing an alkali metal vapor at an elevated temperature and concurrently being able to excite and probe atomic transitions within. Typically glass is used as the material to construct the container, as it is easy to manipulate into any geometry and offers thermal, mechanical, and optical properties that no other material is capable. Unfortunately it has been well established that alkali metal gasses/vapors react readily with silica containing glass and results in a progressive darkening of the material. As the darkening reaction progresses, the optical transmission properties of the glass progressively degrade to an eventual point of uselessness. Alkali metals have been used extensively in frequency standards and magnetometers. The finite life of these alkali metal vapor-containing devices has been accepted despite varying attempts by different teams to solve this problem. As a viable solution, it has been identified there exist a family of glass compositions that contain a marginal amount of silica, may be lampworked using traditional glassblowing techniques, and that offer substantially better alkali vapor resistance. The evaluation of these glasses and their resistance to sodium and lithium vapor at varying pressures and temperatures are discussed.

  17. Neuropsychiatric manifestations of alkali metal deficiency and excess.

    PubMed

    Yung, C Y

    1984-01-01

    The alkali metals from the Group IA of the periodic table (lithium, sodium, potassium, rubidium, cesium and francium) are reviewed. The neuropsychiatric aspects of alkali metal deficiencies and excesses (intoxications) are described. Emphasis was placed on lithium due to its clinical uses. The signs and symptoms of these conditions are characterized by features of an organic brain syndrome with delirium and encephalopathy prevailing. There are no clinically distinctive features that could be reliably used for diagnoses. Sodium and potassium are two essential alkali metals in man. Lithium is used as therapeutic agent in bipolar affective disorders. Rubidium has been investigated for its antidepressant effect in a group of psychiatric disorders. Cesium is under laboratory investigation for its role in carcinogenesis and in depressive illness. Very little is known of francium due to its great instability for experimental study.

  18. Neuropsychiatric manifestations of alkali metal deficiency and excess

    SciTech Connect

    Yung, C.Y.

    1984-01-01

    The alkali metals from the Group IA of the periodic table (lithium, sodium, potassium, rubidium, cesium and francium) are reviewed. The neuropsychiatric aspects of alkali metal deficiencies and excesses (intoxications) are described. Emphasis was placed on lithium due to its clinical uses. The signs and symptoms of these conditions are characterized by features of an organic brain syndrome with delirium and encephalopathy prevailing. There are no clinically distinctive features that could be reliably used for diagnoses. Sodium and potassium are two essential alkali metals in man. Lithium is used as therapeutic agent in bipolar affective disorders. Rubidium has been investigated for its antidepressant effect in a group of psychiatric disorders. Cesium is under laboratory investigation for its role in carcinogenesis and in depressive illness. Very little is known of francium due to its great instability for experimental study.

  19. Spectroscopic and theoretical study on alkali metal phenylacetates

    NASA Astrophysics Data System (ADS)

    Regulska, E.; Świsłocka, R.; Samsonowicz, M.; Lewandowski, W.

    2013-07-01

    The influence of lithium, sodium, potassium, rubidium and cesium cations on the electronic system of phenylacetic acid was studied. The FT-IR, FT-Raman and 1H and 13C NMR spectra were recorded for studied compounds. Characteristic shifts in IR and NMR spectra along alkali metal phenylacetates were observed. Good correlations between the wavenumbers of the vibrational bands in the IR spectra of phenylacetates and some alkali metal parameters such as ionic potential, electronegativity, inverse of atomic mass, atomic radius and ionization energy were found. The density functional hybrid method B3LYP with 6-311++G** basis set was used to calculate optimized geometrical structures of studied compounds. Aromaticity indices, atomic charges, dipole moments and energies were calculated as well as the wavenumbers and intensities of IR spectra and chemical shifts in NMR spectra. The theoretical parameters were compared to experimental characteristic of alkali metal phenylacetates.

  20. Spill-Resistant Alkali-Metal-Vapor Dispenser

    NASA Technical Reports Server (NTRS)

    Klipstein, William

    2005-01-01

    A spill-resistant vessel has been developed for dispensing an alkali-metal vapor. Vapors of alkali metals (most commonly, cesium or rubidium, both of which melt at temperatures slightly above room temperature) are needed for atomic frequency standards, experiments in spectroscopy, and experiments in laser cooling. Although the present spill-resistant alkali-metal dispenser was originally intended for use in the low-gravity environment of outer space, it can also be used in normal Earth gravitation: indeed, its utility as a vapor source was confirmed by use of cesium in a ground apparatus. The vessel is made of copper. It consists of an assembly of cylinders and flanges, shown in the figure. The uppermost cylinder is a fill tube. Initially, the vessel is evacuated, the alkali metal charge is distilled into the bottom of the vessel, and then the fill tube is pinched closed to form a vacuum seal. The innermost cylinder serves as the outlet for the vapor, yet prevents spilling by protruding above the surface of the alkali metal, no matter which way or how far the vessel is tilted. In the event (unlikely in normal Earth gravitation) that any drops of molten alkali metal have been shaken loose by vibration and are floating freely, a mesh cap on top of the inner cylinder prevents the drops from drifting out with the vapor. Liquid containment of the equivalent of 1.2 grams of cesium was confirmed for all orientations with rubbing alcohol in one of the prototypes later used with cesium.

  1. Transport properties of alkali metal doped fullerides

    SciTech Connect

    Yadav, Daluram Yadav, Nishchhal

    2015-07-31

    We have studied the intercage interactions between the adjacent C{sub 60} cages and expansion of lattice due to the intercalation of alkali atoms based on the spring model to estimate phonon frequencies from the dynamical matrix for the intermolecular alkali-C{sub 60} phonons. We considered a two-peak model for the phonon density of states to investigate the nature of electron pairing mechanism for superconducting state in fullerides. Coulomb repulsive parameter and the electron phonon coupling strength are obtained within the random phase approximation. Transition temperature, T{sub c}, is obtained in a situation when the free electrons in lowest molecular orbital are coupled with alkali-C{sub 60} phonons as 5 K, which is much lower as compared to reported T{sub c} (20 K). The superconducting pairing is mainly driven by the high frequency intramolecular phonons and their effects enhance it to 22 K. The importance of the present study, the pressure effect and normal state transport properties are calculated within the same model leading superconductivity.

  2. Heavy Metal Pumps in Plants

    SciTech Connect

    Harper, J.F.

    2000-10-01

    The long term goal of the funded research is to understand how heavy metals are taken up from the soil and translocated throughout the plant. The potential application of this research is to create plants with better heavy metal uptake systems and thereby improve the ability of these plants to help clean up toxic metals from soils. A rate limiting step is using plant for bioremediation is the normally poor capacity of plants to concentrate toxic metals. Our interest in metal ion transport systems includes those for essential mineral nutrients such as molybdenum, copper, iron, manganese, as well as toxic metals such as cerium, mercury, cesium, cadmium, arsenic and selenium. Understanding the pathways by which toxic metals accumulate in plants will enable the engineering of plants to exclude toxic metals and create healthier food sources, or to extract toxic metals from the soil as a strategy to clean up polluted lands and water.

  3. High capacity nickel battery material doped with alkali metal cations

    DOEpatents

    Jackovitz, John F.; Pantier, Earl A.

    1982-05-18

    A high capacity battery material is made, consisting essentially of hydrated Ni(II) hydroxide, and about 5 wt. % to about 40 wt. % of Ni(IV) hydrated oxide interlayer doped with alkali metal cations selected from potassium, sodium and lithium cations.

  4. Method of assembling and sealing an alkali metal battery

    DOEpatents

    Elkins, Perry E.; Bell, Jerry E.; Harlow, Richard A.; Chase, Gordon G.

    1983-01-01

    A method of initially assembling and then subsequently hermetically sealing a container portion of an alkali metal battery to a ceramic portion of such a battery is disclosed. Sealing surfaces are formed respectively on a container portion and a ceramic portion of an alkali metal battery. These sealing surfaces are brought into juxtaposition and a material is interposed therebetween. This interposed material is one which will diffuse into sealing relationship with both the container portion and the ceramic portion of the alkali metal battery at operational temperatures of such a battery. A pressure is applied between these sealing surfaces to cause the interposed material to be brought into intimate physical contact with such juxtaposed surfaces. A temporary sealing material which will provide a seal against a flow of alkali metal battery reactants therethrough at room temperatures and is applied over the juxtaposed sealing surfaces and material interposed therebetween. The entire assembly is heated to an operational temperature so that the interposed material diffuses into the container portion and the ceramic portion to form a hermetic seal therebetween. The pressure applied to the juxtaposed sealing surfaces is maintained in order to ensure the continuation of the hermetic seal.

  5. An analytical equation of state for molten alkali metals

    SciTech Connect

    Ghatee, M.H.; Boushehri, A.

    1995-11-01

    The paper brings the molten alkali metals into the scope of a new statistical mechanical equation of state that is known to satisfy normal fluids over the whole range. As for normal fluids, the latent heat of vaporization and density at freezing temperature are the only inputs (scaling factors). The corresponding-states correlation of normal fluids is used to calculate the second virial coefficient, B{sub 2}(T), of alkali metals, which is scarce experimentally and its calculation is complicated by dimer formation. Calculations of the other two temperature-dependent constants, {alpha}(T) and b (T), follow by scaling. The virial coefficients of alkali metals cannot be expected to obey a law of corresponding states for normal fluids. The fact that two potentials are involved may be the reason for this. Thus, alkali metals have the characteristics of interacting through singlet and triple potentials so that the treatment by a single potential here is fortuitous. The adjustable parameter of the equation of state, {Gamma}, compensates for the uncertainties in B{sub 2}(T). The procedure used to calculate the density of liquids Li through Cs from the freezing line up to several hundred degrees above the boiling temperatures. The results are within 5%.

  6. Aqueous alkali metal hydroxide insoluble cellulose ether membrane

    NASA Technical Reports Server (NTRS)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1969-01-01

    A membrane that is insoluble in an aqueous alkali metal hydroxide medium is described. The membrane is a resin which is a water-soluble C2-C4 hydroxyalkyl cellulose ether polymer and an insolubilizing agent for controlled water sorption, a dialytic and electrodialytic membrane. It is particularly useful as a separator between electrodes or plates in an alkaline storage battery.

  7. Method of assembling and sealing an alkali metal battery

    DOEpatents

    Elkins, P.E.; Bell, J.E.; Harlow, R.A.; Chase, G.G.

    1983-03-01

    A method of initially assembling and then subsequently hermetically sealing a container portion of an alkali metal battery to a ceramic portion of such a battery is disclosed. Sealing surfaces are formed respectively on a container portion and a ceramic portion of an alkali metal battery. These sealing surfaces are brought into juxtaposition and a material is interposed there between. This interposed material is one which will diffuse into sealing relationship with both the container portion and the ceramic portion of the alkali metal battery at operational temperatures of such a battery. A pressure is applied between these sealing surfaces to cause the interposed material to be brought into intimate physical contact with such juxtaposed surfaces. A temporary sealing material which will provide a seal against a flow of alkali metal battery reactants there through at room temperatures and is applied over the juxtaposed sealing surfaces and material interposed there between. The entire assembly is heated to an operational temperature so that the interposed material diffuses into the container portion and the ceramic portion to form a hermetic seal there between. The pressure applied to the juxtaposed sealing surfaces is maintained in order to ensure the continuation of the hermetic seal. 4 figs.

  8. Stabilized Alkali-Metal Ultraviolet-Band-Pass Filters

    NASA Technical Reports Server (NTRS)

    Mardesich, Nick; Fraschetti, George A.; Mccann, Timothy; Mayall, Sherwood D.; Dunn, Donald E.; Trauger, John T.

    1995-01-01

    Layers of bismuth 5 to 10 angstrom thick incorporated into alkali-metal ultraviolet-band-pass optical filters by use of advanced fabrication techniques. In new filters layer of bismuth helps to reduce surface migration of sodium. Sodium layer made more stable and decreased tendency to form pinholes by migration.

  9. 40 CFR 721.5985 - Fatty alkyl phosphate, alkali metal salt (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty alkyl phosphate, alkali metal... Specific Chemical Substances § 721.5985 Fatty alkyl phosphate, alkali metal salt (generic). (a) Chemical... as a fatty alkyl phosphate, alkali metal salt (PMN P-99-0385) is subject to reporting under...

  10. 40 CFR 721.5452 - Alkali metal salt of halogenated organoborate (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkali metal salt of halogenated... Specific Chemical Substances § 721.5452 Alkali metal salt of halogenated organoborate (generic). (a... generically as alkali metal salt of halogenated organoborate (PMN P-00-0638) is subject to reporting...

  11. 40 CFR 721.5985 - Fatty alkyl phosphate, alkali metal salt (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Fatty alkyl phosphate, alkali metal... Specific Chemical Substances § 721.5985 Fatty alkyl phosphate, alkali metal salt (generic). (a) Chemical... as a fatty alkyl phosphate, alkali metal salt (PMN P-99-0385) is subject to reporting under...

  12. 40 CFR 721.5452 - Alkali metal salt of halogenated organoborate (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkali metal salt of halogenated... Specific Chemical Substances § 721.5452 Alkali metal salt of halogenated organoborate (generic). (a... generically as alkali metal salt of halogenated organoborate (PMN P-00-0638) is subject to reporting...

  13. 40 CFR 721.5985 - Fatty alkyl phosphate, alkali metal salt (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Fatty alkyl phosphate, alkali metal... Specific Chemical Substances § 721.5985 Fatty alkyl phosphate, alkali metal salt (generic). (a) Chemical... as a fatty alkyl phosphate, alkali metal salt (PMN P-99-0385) is subject to reporting under...

  14. 40 CFR 721.5452 - Alkali metal salt of halogenated organoborate (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkali metal salt of halogenated... Specific Chemical Substances § 721.5452 Alkali metal salt of halogenated organoborate (generic). (a... generically as alkali metal salt of halogenated organoborate (PMN P-00-0638) is subject to reporting...

  15. 40 CFR 721.5985 - Fatty alkyl phosphate, alkali metal salt (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Fatty alkyl phosphate, alkali metal... Specific Chemical Substances § 721.5985 Fatty alkyl phosphate, alkali metal salt (generic). (a) Chemical... as a fatty alkyl phosphate, alkali metal salt (PMN P-99-0385) is subject to reporting under...

  16. 40 CFR 721.5985 - Fatty alkyl phosphate, alkali metal salt (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Fatty alkyl phosphate, alkali metal... Specific Chemical Substances § 721.5985 Fatty alkyl phosphate, alkali metal salt (generic). (a) Chemical... as a fatty alkyl phosphate, alkali metal salt (PMN P-99-0385) is subject to reporting under...

  17. 40 CFR 721.5452 - Alkali metal salt of halogenated organoborate (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal salt of halogenated... Specific Chemical Substances § 721.5452 Alkali metal salt of halogenated organoborate (generic). (a... generically as alkali metal salt of halogenated organoborate (PMN P-00-0638) is subject to reporting...

  18. 40 CFR 721.5452 - Alkali metal salt of halogenated organoborate (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkali metal salt of halogenated... Specific Chemical Substances § 721.5452 Alkali metal salt of halogenated organoborate (generic). (a... generically as alkali metal salt of halogenated organoborate (PMN P-00-0638) is subject to reporting...

  19. Alkali Metal Suboxometalates-Structural Chemistry between Salts and Metals.

    PubMed

    Wörsching, Matthias; Hoch, Constantin

    2015-07-20

    The crystal structures of the new cesium-poor alkali metal suboxometalates Cs10MO5 (M = Al, Ga, Fe) show both metallic and ionic bonding following the formal description (Cs(+))10(MO4(5-))(O(2-))·3e(-). Comparable to the cesium-rich suboxometalates Cs9MO4 (M = Al, Ga, In, Fe, Sc) with ionic subdivision (Cs(+))9(MO4(5-))·4e(-), they contain an oxometalate anion [M(III)O4](5-) embedded in a metallic matrix of cesium atoms. Columnlike building units form with prevalent ionic bonding inside and metallic bonding on the outer surface. In the cesium-rich suboxometalates Cs9MO4, additional cesium atoms with no contact to any anion are inserted between columns of the formal composition [Cs8MO4]. In the cesium-poor suboxometalates Cs10MO5, the same columns are extended by face-sharing [Cs6O] units, and no additional cesium atoms are present. The terms "cesium-rich" and "cesium-poor" here refer to the Cs:O ratio. The new suboxometalates Cs10MO5 crystallize in two modifications with new structure types. The orthorhombic modification adopts a structure with four formula units per unit cell in space group Pnnm with a = 11.158(3) Å, b = 23.693(15) Å, and c = 12.229(3) Å for Cs10AlO5. The monoclinic modification crystallizes with eight formula units per unit cell in space group C2/c with a = 21.195(3) Å, b = 12.480(1) Å, c = 24.120(4) Å, and β = 98.06(1)° for Cs10AlO5. Limits to phase formation are given by the restriction that the M atoms must be trivalent and by geometric size restrictions for the insertion of [Cs6O] blocks in Cs10MO5. All of the suboxometalate structures show similar structural details and form mixed crystal series with statistical occupation for the M elements following the patterns Cs9(M(1)xM(2)1-x)O4 and Cs10(M(1)xM(2)1-x)O5. The suboxometalates are a new example of ordered intergrowth of ionic and metallic structure elements, allowing for the combination of properties related to both ionic and metallic materials.

  20. Heavy Metal Stars

    NASA Astrophysics Data System (ADS)

    2001-08-01

    thereafter dies as a burnt-out, dim "white dwarf" . Stars with masses between 0.8 and 8 times that of the Sun are believed to evolve to AGB-stars and to end their lives in this particular way. At the same time, they produce beautiful nebulae like the "Dumbbell Nebula". Our Sun will also end its active life this way, probably some 7 billion years from now. Low-metallicity stars The detailed understanding of the "s-process" and, in particular, where it takes place inside an AGB-star, has been an area of active research for many years. Current state-of-the-art computer-based stellar models predict that the s-process should be particularly efficient in stars with a comparatively low content of metals ("metal-poor" or "low-metallicity" stars) . In such stars - which were born at an early epoch in our Galaxy and are therefore quite old - the "s-process" is expected to effectively produce atomic nuclei all the way up to the most heavy, stable ones, like Lead (atomic number 82 [2]) and Bismuth (atomic number 83) - since more neutrons are available per Iron-seed nucleus when there are fewer such nuclei (as compared to the solar composition). Once these elements have been produced, the addition of more s-process neutrons to those nuclei will only produce unstable elements that decay back to Lead. Hence, when the s-process is sufficiently efficient, atomic nuclei with atomic numbers around 82, that is, the Lead region, just continue to pile up. As a result, when compared to stars with "normal" abundances of the metals (like our Sun), those low-metallicity stars should thus exhibit a significant "over-abundance" of those very heavy elements with respect to Iron, in particular of Lead . Looking for Lead Direct observational support for this theoretical prediction would be the discovery of some low-metallicity stars with a high abundance of Lead. At the same time, the measured amounts of all the heavy elements and their relative abundances would provide very valuable information and

  1. Heavy metals and coal combustion

    SciTech Connect

    Danihelka, P.; Ochodek, T.; Noskievic, P.; Seidlerova, J.

    1998-07-01

    Combustion of coal may be an important source of heavy metals pollution. The distribution of heavy metals during combustion process has been studied in six power plants, where fuel, bottom ash, fly ash and emissions have been analyzed and the relative concentrations of heavy metals have been estimated. For the most volatile metals (arsenic, antimony, lead, and zinc), the redistribution process involving condensation on surface is probable. Some metals like manganese or chromium are concentrated rather in coarse particles. In such cases, no clear conclusion can be made and probably several mechanisms are involved, including mineral form of metal. Typical results of low chlorine coal (0.01--0.03% Cl) exhibit increasing concentration of volatile metals in the magnitude of around one order when going from bottom ash to emissions. Different results have been found in similar operation conditions in the case of high content of chlorine in coal (0.3% of Cl in coal). In this case, the concentration of metals in emissions is significantly higher and also nickel, copper and manganese concentrations increase. It seems to be probable that chlorine in the coal increases the redistribution of metals by volatile chlorides formation. At three operation condition (nominal output, 70% and 40% respectively) emission factors of heavy metals have been estimated for 35 MW stoker-fired boiler. Ba, Pb, Sb and Zn increased their emission factors and Cr and Mn decreased when output was decreased. Heavy metals pollution caused by emissions from combustion of coal may be decreased by fine particles removal, other possibilities (metals extraction from the coal, changes of condition in the flame) are rather limited.

  2. Non-Adiabatic Atomic Transitions: Computational Cross Section Calculations of Alkali Metal-Noble Gas Collisions

    DTIC Science & Technology

    2011-09-01

    collisions were computationally simulated. The alkali metals were potassium, rubidium, and cesium and the noble gas partners were helium, neon, and argon...195 20. Spin-Orbit split energies of Potassium, Rubidium, and Cesium ...composed of an alkali metal typically Rubidium[26, 37] or Cesium [5, 18]. The unique character of the alkali atoms, having a single valence electron in

  3. Chemical compatibility of structural materials in alkali metals

    SciTech Connect

    Natesan, K.; Rink, D.L.; Haglund, R.

    1995-04-01

    The objectives of this task are to (a) evaluate the chemical compatibility of structural alloys such as V-5 wt.%Cr-5 wt.%Ti alloy and Type 316 stainless steel for application in liquid alkali metals such as lithium and sodium-78 wt.% potassium (NaK) at temperatures in the range that are of interest for International Thermonuclear Experimental Reactor (ITER); (b) evaluate the transfer of nonmetallic elements such as oxygen, nitrogen, carbon, and hydrogen between structural materials and liquid metals; and (c) evaluate the effects of such transfers on the mechanical and microstructural characteristics of the materials for long-term service in liquid-metal-environments.

  4. Selective reduction of heavy metals

    SciTech Connect

    Bjorling, G.

    1984-12-11

    The present invention relates to selective reduction of heavy metals out of finey grained, substantially oxidic material by blowing the oxidic material into a furnace together with an amount of reducing agent required for obtaining desired selectivity while simultaneously heat energy is supplied by a gas heated in a plasma generator, the temperature being adjusted to such a level as to correspond to the oxygen potential at which the desired metals are transformed into a particular, isolatable phase as metal melt, metal vapor, speiss or matte and at which the remaining metals enter into a slag phase and can be isolated as slag melt.

  5. Heavy metals and coal combustion

    SciTech Connect

    Danihelka, P.; Ochodek, T.; Noskievic, P.; Seidlerova, J.

    1998-04-01

    Combustion of coal may be an important source of heavy metals pollution. The distribution of heavy metals during combustion process has been studied in six power plants, where fuel, bottom ash, fly ash and emissions have been analysed and the relative concentrations of heavy metals have been estimated. For the most volatile metals (arsenic, antimony, lead, and zinc), the redistribution process involving condensation on surface is probable. Some metals like manganese or chromium are concentrated rather in coarse particles. In such cases, no clear conclusion can be made and probably several mechanisms are involved, including mineral form of metal. Typical results of low chlorine coal (0.01-0.03% Cl) exhibit increasing concentration of volatile metals in the magnitude of around one order when going from bottom ash to emissions. Different results have been found in similar operation conditions in the case of high content of chlorine in coal (0.3 % of Cl in coal). In this case, the concentration of metals in emissions is significantly higher and also nickel, copper and manganese concentrations increase. It seems to be probable that chlorine in the coal increases the redistribution of metals by volatile chlorides formation.

  6. Transversely diode-pumped alkali metal vapour laser

    SciTech Connect

    Parkhomenko, A I; Shalagin, A M

    2015-09-30

    We have studied theoretically the operation of a transversely diode-pumped alkali metal vapour laser. For the case of high-intensity laser radiation, we have obtained an analytical solution to a complex system of differential equations describing the laser. This solution allows one to exhaustively determine all the energy characteristics of the laser and to find optimal parameters of the working medium and pump radiation (temperature, buffer gas pressure, and intensity and width of the pump spectrum). (lasers)

  7. Radioisotope powered alkali metal thermoelectric converter design for space systems

    NASA Technical Reports Server (NTRS)

    Sievers, R. K.; Bankston, C. P.

    1988-01-01

    The design concept of an alkali-metal thermoelectric converter (AMTEC) for 15-30-percent-efficient conversion of heat from the General Purpose (radioisotope) Heat Source (GPHS) on spacecraft is presented. The basic physical principles of the conversion cycle are outlined; a theoretical model is derived; a modular design is described and illustrated with drawings; and the overall AMTEC/GPHS system design is characterized. Predicted performance data are presented in extensive tables and graphs and discussed in detail.

  8. Alkali Metal Cation Transport and Homeostasis in Yeasts

    PubMed Central

    Ariño, Joaquín; Ramos, José; Sychrová, Hana

    2010-01-01

    Summary: The maintenance of appropriate intracellular concentrations of alkali metal cations, principally K+ and Na+, is of utmost importance for living cells, since they determine cell volume, intracellular pH, and potential across the plasma membrane, among other important cellular parameters. Yeasts have developed a number of strategies to adapt to large variations in the concentrations of these cations in the environment, basically by controlling transport processes. Plasma membrane high-affinity K+ transporters allow intracellular accumulation of this cation even when it is scarce in the environment. Exposure to high concentrations of Na+ can be tolerated due to the existence of an Na+, K+-ATPase and an Na+, K+/H+-antiporter, which contribute to the potassium balance as well. Cations can also be sequestered through various antiporters into intracellular organelles, such as the vacuole. Although some uncertainties still persist, the nature of the major structural components responsible for alkali metal cation fluxes across yeast membranes has been defined within the last 20 years. In contrast, the regulatory components and their interactions are, in many cases, still unclear. Conserved signaling pathways (e.g., calcineurin and HOG) are known to participate in the regulation of influx and efflux processes at the plasma membrane level, even though the molecular details are obscure. Similarly, very little is known about the regulation of organellar transport and homeostasis of alkali metal cations. The aim of this review is to provide a comprehensive and up-to-date vision of the mechanisms responsible for alkali metal cation transport and their regulation in the model yeast Saccharomyces cerevisiae and to establish, when possible, comparisons with other yeasts and higher plants. PMID:20197501

  9. Process for carbonaceous material conversion and recovery of alkali metal catalyst constituents held by ion exchange sites in conversion residue

    DOEpatents

    Sharp, David W.

    1980-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered for the particles by contacting or washing them with an aqueous solution containing calcium or magnesium ions in an alkali metal recovery zone at a low temperature, preferably below about 249.degree. F. During the washing or leaching process, the calcium or magnesium ions displace alkali metal ions held by ion exchange sites in the particles thereby liberating the ions and producing an aqueous effluent containing alkali metal constituents. The aqueous effluent from the alkali metal recovery zone is then recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

  10. The unexpected properties of alkali metal iron selenide superconductors

    SciTech Connect

    Dagotto, Elbio R

    2013-01-01

    The iron-based superconductors that contain FeAs layers as the fundamental building block in the crystal structures have been rationalized in the past using ideas based on the Fermi surface nesting of hole and electron pockets when in the presence of weak Hubbard U interactions. This approach seemed appropriate considering the small values of the magnetic moments in the parent compounds and the clear evidence based on photoemission experiments of the required electron and hole pockets. However, recent results in the context of alkali metal iron selenides, with generic chemical composition AxFe2ySe2 (A alkali metal element), have challenged those previous ideas since at particular compositions y the low-temperature ground states are insulating and display antiferromagnetic order with large iron magnetic moments. Moreover, angle-resolved photoemission studies have revealed the absence of hole pockets at the Fermi level in these materials. The present status of this exciting area of research, with the potential to alter conceptually our understanding of the ironbased superconductors, is here reviewed, covering both experimental and theoretical investigations. Other recent related developments are also briefly reviewed, such as the study of selenide two-leg ladders and the discovery of superconductivity in a single layer of FeSe. The conceptual issues considered established for the alkali metal iron selenides, as well as several issues that still require further work, are discussed.

  11. Neutron imaging of alkali metal heat pipes

    SciTech Connect

    Kihm, Ken; Kirchoff, Eric; Golden, Matt; Rosenfeld, J.; Rawal, S.; Pratt, D.; Bilheux, Hassina Z; Walker, Lakeisha MH; Voisin, Sophie; Hussey, Dan

    2013-01-01

    High-temperature heat pipes are two-phase, capillary driven heat transfer devices capable of passively providing high thermal fluxes. Such a device using a liquid-metal coolant can be used as a solution for successful thermal management on hypersonic flight vehicles. Imaging of the liquid-metal coolant inside will provide valuable information in characterizing the detailed heat and mass transport. Neutron imaging possesses an inherent advantage from the fact that neutrons penetrate the heat pipe metal walls with very little attenuation, but are significantly attenuated by the liquid metal contained inside. Using the BT-2 beam line at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, preliminary efforts have been conducted on a nickel-sodium heat pipe. The contrast between the attenuated beam and the background is calculated to be approximately 3%. This low contrast requires sacrifice in spatial or temporal resolution so efforts have since been concentrated on lithium (Li) which has a substantially larger neutron attenuation cross section. Using the CG-1D beam line at the High Flux Isotope Reactor (HFIR) of Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, the first neutron images of high-temperature molybdenum (Mo)-Li heat pipes have been achieved. The relatively high neutron cross section of Li allows for the visualization of the Li working fluid inside the heat pipes. The evaporator region of a gravity assisted cylindrical heat pipe prototype 25 cm long was imaged from start-up to steady state operation up to approximately 900 C. In each corner of the square bore inside, the capillary action raises the Li meniscus above the bulk Li pool in the evaporator region. As the operational temperature changes, the meniscus shapes and the bulk meniscus height also changes. Furthermore, a three-dimensional tomographic image is also reconstructed from the total of 128 projection images taken 1.4o apart in which the Li had

  12. Generation and characterization of alkali metal clusters in Y-FAU zeolites. An ESR and MAS NMR spectroscopic study

    NASA Astrophysics Data System (ADS)

    Hannus, István; Béres, Attila; Nagy, János B.; Halász, János; Kiricsi, Imre

    1997-06-01

    Charged and neutral metal clusters of various compositions and sizes can be prepared by controlling the alkali metal content by the decomposition of alkali azides and the composition of the host zeolite by ion-exchange. ESR signals show that electron transfer from alkali metal atoms to alkali metal cations does occur, but in a direction opposite to that predicted by the gas-phase thermochemistry. Alkali metal clusters proved to be very active basic catalytic centers.

  13. Process for removing heavy metal compounds from heavy crude oil

    DOEpatents

    Cha, Chang Y.; Boysen, John E.; Branthaver, Jan F.

    1991-01-01

    A process is provided for removing heavy metal compounds from heavy crude oil by mixing the heavy crude oil with tar sand; preheating the mixture to a temperature of about 650.degree. F.; heating said mixture to up to 800.degree. F.; and separating tar sand from the light oils formed during said heating. The heavy metals removed from the heavy oils can be recovered from the spent sand for other uses.

  14. Alkali metal cation-hexacyclen complexes: effects of alkali metal cation size on the structure and binding energy.

    PubMed

    Austin, C A; Rodgers, M T

    2014-07-24

    Threshold collision-induced dissociation (CID) of alkali metal cation-hexacyclen (ha18C6) complexes, M(+)(ha18C6), with xenon is studied using guided ion beam tandem mass spectrometry techniques. The alkali metal cations examined here include: Na(+), K(+), Rb(+), and Cs(+). In all cases, M(+) is the only product observed, corresponding to endothermic loss of the intact ha18C6 ligand. The cross-section thresholds are analyzed to extract zero and 298 K M(+)-ha18C6 bond dissociation energies (BDEs) after properly accounting for the effects of multiple M(+)(ha18C6)-Xe collisions, the kinetic and internal energy distributions of the M(+)(ha18C6) and Xe reactants, and the lifetimes for dissociation of the activated M(+)(ha18C6) complexes. Ab initio and density functional theory calculations are used to determine the structures of ha18C6 and the M(+)(ha18C6) complexes, provide molecular constants necessary for the thermodynamic analysis of the energy-resolved CID data, and theoretical estimates for the M(+)-ha18C6 BDEs. Calculations using a polarizable continuum model are also performed to examine solvent effects on the binding. In the absence of solvent, the M(+)-ha18C6 BDEs decrease as the size of the alkali metal cation increases, consistent with the noncovalent nature of the binding in these complexes. However, in the presence of solvent, the ha18C6 ligand exhibits selectivity for K(+) over the other alkali metal cations. The M(+)(ha18C6) structures and BDEs are compared to those previously reported for the analogous M(+)(18-crown-6) and M(+)(cyclen) complexes to examine the effects of the nature of the donor atom (N versus O) and the number donor atoms (six vs four) on the nature and strength of binding.

  15. Solvent effects and alkali metal ion catalysis in phosphodiester hydrolysis.

    PubMed

    Gomez-Tagle, Paola; Vargas-Zúñiga, Idania; Taran, Olga; Yatsimirsky, Anatoly K

    2006-12-22

    The kinetics of the alkaline hydrolysis of bis(p-nitrophenyl) phosphate (BNPP) have been studied in aqueous DMSO, dioxane, and MeCN. In all solvent mixtures the reaction rate steadily decreases to half of its value in pure water in the range of 0-70 vol % of organic cosolvent and sharply increases in mixtures with lower water content. Correlations based on different scales of solvent empirical parameters failed to describe the solvent effect in this system, but it can be satisfactorily treated in terms of a simplified stepwise solvent-exchange model. Alkali metal ions catalyze the BNPP hydrolysis but do not affect the rate of hydrolysis of neutral phosphotriester p-nitrophenyl diphenyl phosphate in DMSO-rich mixtures. The catalytic activity decreases in the order Li+ > Na+ > K+ > Rb+ > Cs+. For all cations except Na+, the reaction rate is first-order in metal ion. With Na+, both first- and second-order kinetics in metal ions are observed. Binding constants of cations to the dianionic transition state of BNPP alkaline hydrolysis are of the same order of magnitude and show a similar trend as their binding constants to p-nitrophenyl phosphate dianion employed as a transition-state model. The appearance of alkali metal ion catalysis in a medium, which solvates metal ions stronger than water, is attributed to the increased affinity of cations to dianions, which undergo a strong destabilization in the presence of an aprotic dipolar cosolvent.

  16. Formation of alkali-metal nanoparticles in alkali-silicate glasses under electron irradiation and thermal processing

    NASA Astrophysics Data System (ADS)

    Bochkareva, E. S.; Sidorov, A. I.; Ignat'ev, A. I.; Nikonorov, N. V.; Podsvirov, O. A.

    2017-02-01

    Experiments and numerical simulation show that the irradiation of alkali-containing glasses using electrons at an energy of 35 keV and the subsequent thermal processing at a temperature above the vitrification point lead to the formation of spherical metal (lithium, sodium, and potassium) nanoparticles with oxide sheaths that exhibit plasmon resonances in the visible spectral range. Glasses containing two alkali metals exhibit mutual effect of metals on the formation of nanoparticles with two compositions due to the difference of ion radii and mobilities of metal ions.

  17. Heavy metals extraction by microemulsions.

    PubMed

    Dantas, T N Castro; Dantas Neto, A A; Moura, M C P A; Barros Neto, E L; Forte, K R; Leite, R H L

    2003-06-01

    The objective of this study is the heavy metal extraction by microemulsion, using regional vegetable oils as surfactants. Firstly, the main parameters, which have influence in the microemulsion region, such as: nature of cosurfactant, influence of cosurfactant (C)/surfactant (S) ratio and salinity were studied, with the objective of choosing the best extraction system. The extraction/reextraction process by microemulsion consists of two stages. In the first one, the heavy metal ion present in the aqueous phase is extracted by the microemulsion. In a second step, the reextraction process occurs: the microemulsion phase, rich in metal, is acidified and the metal is recovered in a new aqueous phase, with higher concentration. The used system had the following parameters: surfactant-saponified coconut oil; cosurfactant-n-butanol; oil phase-kerosene; C/S ratio=4; salinity-2% (NaCl); temperature of 27+/-1 degrees C; water phase-aqueous solution that varied according to the heavy metal in study (Cr, Cu, Fe, Mn, Ni and Pb). A methodology of experimental planning was used (Scheffé Net) to study the behavior of the extraction in a chosen domain. The extraction was accomplished in one step and yielded extraction percentage higher than 98% for all metals. In the reextraction HCl-8M was used as reextraction agent and the influence of the pH and time were verified. This work showed the great efficiency of the microemulsion, indicating that it is possible to extract selectively the heavy metals from the aqueous phase.

  18. Abatement of Marine Coatings Containing Heavy Metals

    DTIC Science & Technology

    1995-06-01

    in the abatement of heavy metal containing marine coatings. Funding for this...shipyards to be proactive in the area of heavy metal coating systems abatement as current regulations were not "user friendly" in shipboard applications.

  19. Dirac Node Lines in Pure Alkali Earth Metals.

    PubMed

    Li, Ronghan; Ma, Hui; Cheng, Xiyue; Wang, Shoulong; Li, Dianzhong; Zhang, Zhengyu; Li, Yiyi; Chen, Xing-Qiu

    2016-08-26

    Beryllium is a simple alkali earth metal, but has been the target of intensive studies for decades because of its unusual electron behavior at surfaces. The puzzling aspects include (i) severe deviations from the description of the nearly free-electron picture, (ii) an anomalously large electron-phonon coupling effect, and (iii) giant Friedel oscillations. The underlying origins for such anomalous surface electron behavior have been under active debate, but with no consensus. Here, by means of first-principles calculations, we discover that this pure metal system, surprisingly, harbors the Dirac node line (DNL) that in turn helps to rationalize many of the existing puzzles. The DNL is featured by a closed line consisting of linear band crossings, and its induced topological surface band agrees well with previous photoemission spectroscopy observations on the Be (0001) surface. We further reveal that each of the elemental alkali earth metals of Mg, Ca, and Sr also harbors the DNL and speculate that the fascinating topological property of the DNL might naturally exist in other elemental metals as well.

  20. Dirac Node Lines in Pure Alkali Earth Metals

    NASA Astrophysics Data System (ADS)

    Li, Ronghan; Ma, Hui; Cheng, Xiyue; Wang, Shoulong; Li, Dianzhong; Zhang, Zhengyu; Li, Yiyi; Chen, Xing-Qiu

    2016-08-01

    Beryllium is a simple alkali earth metal, but has been the target of intensive studies for decades because of its unusual electron behavior at surfaces. The puzzling aspects include (i) severe deviations from the description of the nearly free-electron picture, (ii) an anomalously large electron-phonon coupling effect, and (iii) giant Friedel oscillations. The underlying origins for such anomalous surface electron behavior have been under active debate, but with no consensus. Here, by means of first-principles calculations, we discover that this pure metal system, surprisingly, harbors the Dirac node line (DNL) that in turn helps to rationalize many of the existing puzzles. The DNL is featured by a closed line consisting of linear band crossings, and its induced topological surface band agrees well with previous photoemission spectroscopy observations on the Be (0001) surface. We further reveal that each of the elemental alkali earth metals of Mg, Ca, and Sr also harbors the DNL and speculate that the fascinating topological property of the DNL might naturally exist in other elemental metals as well.

  1. Efficient destruction of CF4 through in situ generation of alkali metals from heated alkali halide reducing mixtures.

    PubMed

    Lee, Myung Churl; Choi, Wonyong

    2002-03-15

    Perfluorocarbons (PFCs) are the most potent green house gases that are very recalcitrant at destruction. An effective way of converting PFCs using hot solid reagents into safe products has been recently introduced. By investigating the thermal reductive destruction of tetrafluoromethane (CF4) we provided new insight and more physicochemical consideration on this novel process. The complete destruction of CF4was successfully achieved by flowing the gas through a heated reagent bed (400-950 degrees C) that contained powder mixtures of alkali halides, CaO, and Si. The silicon acted as a reducing agent of alkali halides for the in-situ production of alkali metals, and the calcium oxide played the role of a halide ion acceptor. The absence of any single component in this ternary mixture drastically reduced the destruction efficiency of CF4. The CF4 destruction efficiencies with the solid reagent containing the alkali halide, MX, increased in the order of Li approximately Na < K < Cs for alkali cations and I < Br < Cl < F for halide anions. This trend agreed with the endothermicity of the alkali metal generation reaction: the higher the endothermicity, the lower the destruction efficiency. Alkali metal generation was indirectly detected by monitoring H2 production from its reaction with water. The production of alkali metals increased with NaF, KF, and CsF in this order. The CsF/CaO/Si system exhibited the complete destruction of CF4 at as low as 600 degrees C. The solid product analysis by X-ray diffraction (XRD) showed the formation of CaF2 and the depletion of Si with black carbon particles formed in the solid reagent residue. No CO/CO2 and toxic HF and SiF4 formation were detected in the exhaust gas.

  2. 40 CFR 721.10098 - Disubstituted benzoic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... metal salt (generic). 721.10098 Section 721.10098 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10098 Disubstituted benzoic acid, alkali metal salt... identified generically as disubstituted benzoic acid, alkali metal salt (PMN P-03-643) is subject...

  3. 40 CFR 721.4663 - Fluorinated carboxylic acid alkali metal salts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... metal salts. 721.4663 Section 721.4663 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4663 Fluorinated carboxylic acid alkali metal salts. (a) Chemical... fluorinated carboxylic acid alkali metal salts (PMNs P-95-979/980/981) are subject to reporting under...

  4. 40 CFR 721.4663 - Fluorinated carboxylic acid alkali metal salts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... metal salts. 721.4663 Section 721.4663 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4663 Fluorinated carboxylic acid alkali metal salts. (a) Chemical... fluorinated carboxylic acid alkali metal salts (PMNs P-95-979/980/981) are subject to reporting under...

  5. 40 CFR 721.10098 - Disubstituted benzoic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... metal salt (generic). 721.10098 Section 721.10098 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10098 Disubstituted benzoic acid, alkali metal salt... identified generically as disubstituted benzoic acid, alkali metal salt (PMN P-03-643) is subject...

  6. 40 CFR 721.10097 - Disubstituted benzenesulfonic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., alkali metal salt (generic). 721.10097 Section 721.10097 Protection of Environment ENVIRONMENTAL... metal salt (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as disubstituted benzenesulfonic acid, alkali metal salt (PMN...

  7. 40 CFR 721.10098 - Disubstituted benzoic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... metal salt (generic). 721.10098 Section 721.10098 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10098 Disubstituted benzoic acid, alkali metal salt... identified generically as disubstituted benzoic acid, alkali metal salt (PMN P-03-643) is subject...

  8. 40 CFR 721.4663 - Fluorinated carboxylic acid alkali metal salts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... metal salts. 721.4663 Section 721.4663 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4663 Fluorinated carboxylic acid alkali metal salts. (a) Chemical... fluorinated carboxylic acid alkali metal salts (PMNs P-95-979/980/981) are subject to reporting under...

  9. 40 CFR 721.4663 - Fluorinated carboxylic acid alkali metal salts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... metal salts. 721.4663 Section 721.4663 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4663 Fluorinated carboxylic acid alkali metal salts. (a) Chemical... fluorinated carboxylic acid alkali metal salts (PMNs P-95-979/980/981) are subject to reporting under...

  10. 40 CFR 721.10097 - Disubstituted benzenesulfonic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., alkali metal salt (generic). 721.10097 Section 721.10097 Protection of Environment ENVIRONMENTAL... metal salt (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as disubstituted benzenesulfonic acid, alkali metal salt (PMN...

  11. 40 CFR 721.10097 - Disubstituted benzenesulfonic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., alkali metal salt (generic). 721.10097 Section 721.10097 Protection of Environment ENVIRONMENTAL... metal salt (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as disubstituted benzenesulfonic acid, alkali metal salt (PMN...

  12. 40 CFR 721.4663 - Fluorinated carboxylic acid alkali metal salts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... metal salts. 721.4663 Section 721.4663 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4663 Fluorinated carboxylic acid alkali metal salts. (a) Chemical... fluorinated carboxylic acid alkali metal salts (PMNs P-95-979/980/981) are subject to reporting under...

  13. 40 CFR 721.10097 - Disubstituted benzenesulfonic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., alkali metal salt (generic). 721.10097 Section 721.10097 Protection of Environment ENVIRONMENTAL... metal salt (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as disubstituted benzenesulfonic acid, alkali metal salt (PMN...

  14. 40 CFR 721.10098 - Disubstituted benzoic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... metal salt (generic). 721.10098 Section 721.10098 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10098 Disubstituted benzoic acid, alkali metal salt... identified generically as disubstituted benzoic acid, alkali metal salt (PMN P-03-643) is subject...

  15. 40 CFR 721.10097 - Disubstituted benzenesulfonic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., alkali metal salt (generic). 721.10097 Section 721.10097 Protection of Environment ENVIRONMENTAL... metal salt (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as disubstituted benzenesulfonic acid, alkali metal salt (PMN...

  16. 40 CFR 721.10098 - Disubstituted benzoic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... metal salt (generic). 721.10098 Section 721.10098 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10098 Disubstituted benzoic acid, alkali metal salt... identified generically as disubstituted benzoic acid, alkali metal salt (PMN P-03-643) is subject...

  17. Alkali-metal silicate binders and methods of manufacture

    NASA Technical Reports Server (NTRS)

    Schutt, J. B. (Inventor)

    1979-01-01

    A paint binder is described which uses a potassium or sodium silicate dispersion having a silicon dioxide to alkali-metal oxide mol ratio of from 4.8:1 to 6.0:1. The binder exhibits stability during both manufacture and storage. The process of making the binder is predictable and repeatable and the binder may be made with inexpensive components. The high mol ratio is achieved with the inclusion of a silicon dioxide hydrogel. The binder, which also employs a silicone, is in the final form of a hydrogel sol.

  18. Nuclear alkali metal Rankine power systems for space applications

    SciTech Connect

    Moyers, J.C.; Holcomb, R.S.

    1986-08-01

    Nucler power systems utilizing alkali metal Rankine power conversion cycles offer the potential for high efficiency, lightweight space power plants. Conceptual design studies are being carried out for both direct and indirect cycle systems for steady state space power applications. A computational model has been developed for calculating the performance, size, and weight of these systems over a wide range of design parameters. The model is described briefly and results from parametric design studies, with descriptions of typical point designs, are presented in this paper.

  19. On strain energy and constitutive relations for alkali metals.

    NASA Technical Reports Server (NTRS)

    Eftis, J.; Arkilic, G. M.; Macdonald, D. E.

    1971-01-01

    An expression for the strain energy as a continuous differentiable function of the Green-Cauchy deformation tensor is obtained for the alkali metals at absolute zero temperature. The development is based on well established quantum and classical calculations of the various contributions to the crystal energy. Stress-deformation relations are next obtained. As a check on the accuracy of the strain energy, theoretical calculations of the values of the second-order elastic coefficients are obtained and compared to known experimental data. The predicted values are shown to compare quite well with the experimental values.

  20. High power density alkali metal thermal to electric converter

    NASA Astrophysics Data System (ADS)

    Sievers, R. K.; Wright, R. F.

    A description is given of the alkali metal thermal-to-electric converter (AMTEC), an emerging technology for static power conversion that has the potential of matching dynamic system efficiency. This high efficiency is produced when cells of beta double prime alumina solid electrolyte (BASE) are series connected, packed in a space-efficient manner, and designed to minimize parasitic heat loss. Design studies have shown that power densities of up to 400 W/kg and efficiencies of up to 35 percent are feasible. This is higher than power densities and efficiencies reported for other AMTEC designs, but continued design studies are necessary to assess applications.

  1. Laser synthesis of ultracold alkali metal dimers: optimization and control

    NASA Astrophysics Data System (ADS)

    Pazyuk, E. A.; Zaitsevskii, A. V.; Stolyarov, A. V.; Tamanis, M.; Ferber, R.

    2015-10-01

    The review concerns the potential of modern high-resolution laser spectroscopy and state-of-the-art ab initio electronic structure calculations used to obtain comprehensive information on the energy and radiative properties of strongly coupled rovibronic diatomic states. The possibility of deperturbation treatment of the intermediate electronically excited states at the experimental (spectroscopic) level of accuracy is demonstrated taking alkali metal dimers as examples. The deperturbation analysis is of crucial importance to optimize multistep laser synthesis and stabilization of ultracold molecular ensembles in their absolute ground level. The bibliography includes 227 references.

  2. Optical response of alkali metal atoms confined in nanoporous glass

    SciTech Connect

    Burchianti, A; Marinelli, C; Mariotti, E; Bogi, A; Marmugi, L; Giomi, S; Maccari, M; Veronesi, S; Moi, L

    2014-03-28

    We study the influence of optical radiation on adsorption and desorption processes of alkali metal atoms confined in nanoporous glass matrices. Exposure of the sample to near-IR or visible light changes the atomic distribution inside the glass nanopores, forcing the entire system to evolve towards a different state. This effect, due to both atomic photodesorption and confinement, causes the growth and evaporation of metastable nanoparticles. It is shown that, by a proper choice of light characteristics and pore size, these processes can be controlled and tailored, thus opening new perspectives for fabrication of nanostructured surfaces. (nanoobjects)

  3. Theoretical determination of the alkali-metal superoxide bond energies

    NASA Technical Reports Server (NTRS)

    Partridge, Harry; Bauschlicher, Charles W., Jr.; Sodupe, Mariona; Langhoff, Stephen R.

    1992-01-01

    The bond dissociation energies for the alkali-metal superoxides have been computed using extensive Gaussian basis sets and treating electron correlation at the modified coupled-pair functional level. Our computed D0 values are 61.4, 37.2, 40.6, and 38.4 kcal/mol for LiO2, NaO2, KO2, and RbO2, respectively. These values, which are expected to be lower bounds and accurate to 2 kcal/mol, agree well with some of the older flame data, but rule out several recent experimental measurements.

  4. Studying the evaporation behavior of heavy metals by thermo-desorption spectrometry.

    PubMed

    Ludwig, C; Lutz, H; Wochele, J; Stucki, S

    2001-12-01

    "Thermal desorption experiments" were carried out during which heavy metal evaporation was studied by on-line monitoring. This could be achieved by the use of a tubular furnace connected to a heavy metal detector, i.e. an ICP-OES (inductively coupled plasma optical emission spectrometer), by a specially designed and patented interface. The spectrograms typically had a time resolution of four different elements per minute using a conventional (sequentially operating) ICP-OES. This study shows how thermo-desorption spectrometry (TDS) can be applied to study the evaporation of high boiling substances, such as heavy metal and alkali metal compounds. The future scope of the method is discussed.

  5. Old acid, new chemistry. Negative metal anions generated from alkali metal oxalates and others.

    PubMed

    Curtis, Sharon; Renaud, Justin; Holmes, John L; Mayer, Paul M

    2010-11-01

    A brief search in Sci Finder for oxalic acid and oxalates will reward the researcher with a staggering 129,280 hits. However, the generation of alkali metal and silver anions via collision-induced dissociation of the metal oxalate anion has not been previously been reported, though Tian and coworkers recently investigated the dissociation of lithium oxalate. The exothermic decomposition of alkali metal oxalate anion to carbon dioxide in the collision cell of a triple quadrupole mass spectrometer leaves no place for the electron to reside, resulting in a double electron-transfer reaction to produce an alkali metal anion. This reaction is facilitated by the negative electron affinity of carbon dioxide and, as such, the authors believe that metal oxalates are potentially unique in this respect. The observed dissociation reactions for collision with argon gas (1.7-1.8 × 10(-3) mbar) for oxalic acid and various alkali metal oxalates are discussed and summarized. Silver oxalate is also included to demonstrate the propensity of this system to generate transition-metal anions, as well.

  6. Nonlinear pressure shifts of alkali-metal atoms in xenon

    NASA Astrophysics Data System (ADS)

    McGuyer, Bart; Xia, Tian; Jau, Yuan-Yu; Happer, William

    2011-05-01

    Compact, portable atomic frequency standards are based on the microwave resonance frequencies of alkali-metal atoms in inert buffer gases. The frequency shift of these resonances due to collisions with the buffer gas is known as the pressure shift. We demonstrate that the microwave resonance frequencies of ground-state 87Rb and 133Cs atoms have a nonlinear dependence on the pressure of the buffer gas Xe. Previous work has demonstrated a nonlinear dependence in Ar and Kr, but not He and N2, which is thought to be due to the loosely-bound van der Waals molecules that are known to form between alkali-metal and buffer-gas atoms in Ar, Kr, and Xe, but not He and N2. Surprisingly, we find that the nonlinearities in Xe are of the opposite sign to those in Ar and Kr, even though the overall shifts for each of these gases are negative. This discrepancy suggests that though the shifts due to the molecules in Ar and Kr are positive, the shifts due to the molecules in Xe are negative. No nonlinearities were observed in the buffer gas Ne to within our experimental accuracy, which suggests that molecules do not form in Ne. Additionally, we present improved measurements of the shifts of Rb and Cs in He and N2 and of Rb in Ar and Kr. This work was supported by the Air Force Office of Scientific Research and the Department of Defense through the NDSEG program.

  7. Study of Alkali-Metal Vapor Diffusion into Glass Materials

    NASA Astrophysics Data System (ADS)

    Sato, Kiminori

    2013-08-01

    To investigate nanodispersion of alkali metals into glass materials, potassium vapor diffusion is conducted using SiO2 glass under well-controlled temperature conditions. It is found that potassium vapor significantly diffuses into the bulk of SiO2 glass with less precipitation on the surface when the host material is kept at a temperature slightly higher than that of the guest material. Positron annihilation spectroscopy reveals that angstrom-scale open spaces in the SiO2 matrix contribute to potassium vapor diffusion. The analysis of potassium concentration obtained by electron probe microanalysis (EPMA) mapping with Fick's second law yields an extremely low potassium diffusion coefficient of 5.1×10-14 cm2 s-1, which arises from the overall diffusion from open spaces of various sizes. The diffusion coefficient attributable to angstrom-scale open spaces is thus expected to be less than ˜10-14 cm2 s-1. The present findings imply that angstrom-scale open spaces play an important role in loading alkali metals into glass materials.

  8. Alkali-metalated forms of thiacalix[4]arenes.

    PubMed

    Zeller, Jürgen; Radius, Udo

    2006-11-13

    The alkali metal salts [TCALi4] (1), [TCANa4] (2), and [TCALK4] (3) of fully deprotonated p-tert-butyltetrathiacalix[4]arene (H(4)TCA) are readily available from the reactions of thiacalix[4]arene and n-BuLi, NaH, or KH as deprotonating reagents. Crystals of the sodium salts 2 and the potassium salt 3 suitable for X-ray diffraction were obtained in the form of the pyridine solvates [(TCA)2Na8.8py] (2.8py) and [(TCA)2K(8).8py] (3.8py). These molecules are dimers in the solid state but are structurally not related. In addition, the reaction of H(4)TCA and lithium hydroxide afforded the structurally characterized complex [(TCA)Li5(OH).4THF] (4). The molecular structure of 4 as well as the structures of 2.8py and 3.8py reveal a close relationship to the corresponding alkali metal salts of the calix[4]arenes.

  9. Effect of chemical and biological degumming on the adsorption of heavy metal by cellulose xanthogenates prepared from Eichhornia crassipes.

    PubMed

    Deng, Li; Geng, Mingjian; Zhu, Duanwei; Zhou, Wenbing; Langdon, Alan; Wu, Hongwei; Yu, Yun; Zhu, Zhenxiang; Wang, Yanyan

    2012-03-01

    Cellulose xanthogenates, derived from the straw of Eichhornia crassipes, were prepared as adsorbents for heavy metals by CS(2) sulfonation and magnesium substitution after degumming with alkali, self-isolated A(1) strain and pectase, respectively. The effects of three degumming treatments were compared by functional groups analysis, surface morphology and surface element composition and heavy metal (Pb(2+)) adsorption studies. The results demonstrate that bio-degumming treatments by A(1) strain and pectase have weaker degumming effects than alkali treatment. However, the surface characteristics of the bio-degumming products, especially the pectase degumming product, are more beneficial to heavy metal adsorption. In comparison to that of the raw plant materials, the Pb(2+) adsorption performances of the three xanthogenates improved significantly, although no obvious differences being observed among themselves. From an environmental point of view, the two bio-degumming treatments, especially the pectase degumming treatment, are more beneficial to prepare heavy metal adsorbents than the alkali degumming treatment.

  10. Difficulties in Interpreting Alkali Metal Trends at the Senior Chemistry Level.

    ERIC Educational Resources Information Center

    de Berg, Kevin

    2001-01-01

    Explores the reasons for the differences in alkali metal reactivity in water in terms of thermodynamics rather than ionization trends. Shows that differences in alkali metal reactivity with water are more appropriately explained in terms of the kinetics of the reactions. (MM)

  11. TOPICAL REVIEW: State dependent particle dynamics in liquid alkali metals

    NASA Astrophysics Data System (ADS)

    Pilgrim, W.-C.; Morkel, Chr

    2006-09-01

    This paper gives a survey of the particle dynamics in the liquid alkali metals observed with inelastic x-ray and neutron scattering experiments. Liquid rubidium and sodium are chosen as model fluids to represent the behaviour of this group of fluids. In the dense metallic monatomic melt the microscopic dynamics is characterized by collective excitations similar to those in the corresponding solids. The collective particle behaviour is appropriately described using a memory function formalism with two relaxation channels for the density correlation. A similar behaviour is found for the single particle motion where again two relaxation mechanisms are needed to accurately reproduce the experimental findings. Special emphasis is given to the density dependence of the particle dynamics. An interesting issue in liquid metals is the metal to non-metal transition, which is observed if the fluid is sufficiently expanded with increasing temperature and pressure. This causes distinct variations in the interparticle interactions, which feed back onto the motional behaviour. The associated variations in structure and dynamics are reflected in the shape of the scattering laws. The experimentally observed features are discussed and compared with simple models and with the results from computer simulations.

  12. Alkali metal derivatives of an ortho-phenylene diamine.

    PubMed

    Robinson, Sarah; Davies, E Stephen; Lewis, William; Blake, Alexander J; Liddle, Stephen T

    2014-03-21

    Treatment of the ortho-phenylene diamine C6H4-1,2-{N(H)Tripp}2 (1, PDAH2, Tripp = 2,4,6-triisopropylphenyl) with two equivalents of MR (M = Li, R = Bu(n); M = Na or K, R = CH2C6H5) afforded the dimetallated alkali metal ortho-phenylene diamide dianion complexes [(PDALi2)(THF)3] (2), [{(PDANa2)(THF)2}2] (3), and [{(PDAK2)(THF)3}2] (4). In contrast, treatment of 2 with two equivalents of rubidium or cesium 2-ethylhexoxide, or treatment of 1 with two equivalents of MR (M = Rb or Cs, R = CH2C6H5) did not afford the anticipated dialkali metal ortho-phenylene diamide dianion derivatives and instead formally afforded the monometallic ortho-diiminosemiquinonate radical anion species [PDAM] (M = Rb, 5; M = Cs, 6). The structure of 2 is monomeric with one lithium coordinated to the two nitrogen centres and the other lithium η(4)-coordinated to the diazabutadiene portion of the PDA scaffold. Similar structural cores are observed for 3 and 4, except that the larger sodium and potassium ions give dimeric structures linked by multi-hapto interactions from the PDA backbone phenyl ring to an alkali metal centre. Complex 5 was not characterised in the solid state, but the structure of 6 reveals coordination of cesium ions to both PDA amide centres and multi-hapto interactions to a PDA backbone phenyl ring in the next unit to generate a one-dimensional polymer. Complexes 2-6 have been variously characterised by X-ray crystallography, multi-nuclear NMR, FTIR, and EPR spectroscopies, and CHN microanalyses.

  13. The Heavy Metal Subculture and Suicide.

    ERIC Educational Resources Information Center

    Stack, Steven; And Others

    1994-01-01

    Assessed relationship between heavy metal music and suicide with data on heavy metal magazine subscriptions and youth suicide in 50 states. Found that, controlling for other predictors of suicide, greater strength of metal subculture, higher youth suicide rate, suggests that music perhaps nurtures suicidal tendencies already present in subculture.…

  14. Industrial hygiene of selected heavy metals

    SciTech Connect

    Woodring, J.L.

    1993-08-01

    The industrial hygiene of heavy metals consists of recognition, evaluation, and control of exposures in the occupational environment. Several of these metals have been in use since ancient times. Reports of health effects and poisonings from overexposures also have a long history. This report discusses the industrial hygiene of the heavy metals, lead, cadmium, mercury, and manganese.

  15. Hydride encapsulation by molecular alkali-metal clusters.

    PubMed

    Haywood, Joanna; Wheatley, Andrew E H

    2008-07-14

    The sequential treatment of group 12 and 13 Lewis acids with alkali-metal organometallics is well established to yield so-called ''ate' complexes, whereby the Lewis-acid metal undergoes nucleophilic attack to give an anion, at least one group 1 metal acting to counter this charge. However, an alternative, less well recognised, reaction pathway involves the Lewis acid abstracting hydride from the organolithium reagent via a beta-elimination mechanism. It has recently been shown that in the presence of N,N'-bidentate ligands this chemistry can be harnessed to yield a new type of molecular main-group metal cluster in which the abstracted LiH is effectively trapped, with the hydride ion occupying an interstitial site in the cluster core. Discussion focuses on the development of this field, detailing advances in our understanding of the roles of Lewis acid, organolithium, and amine substrates in the syntheses of these compounds. Structure-types are discussed, as are efforts to manipulate cluster geometry and composition as well as hydride-coordination. Embryonic mechanistic studies are reported, as well as attempts to generate hydride-encapsulation clusters under catalytic control.

  16. Biomolecules for removal of heavy metal.

    PubMed

    Singh, Namita Ashish

    2017-02-23

    Heavy metals are natural constituents of the earth's crust, but some heavy metals like cadmium, lead, mercury, arsenic etc. are injurious to living organisms at higher concentration. Nowadays, anthropogenic activities have altered geochemical cycles and biochemical balance of heavy metals. Biomolecules are used nowadays for removal of heavy metals compared to other synthetic biosorbents due to their environmental friendly nature and cost effectiveness. The goal of this work is to review research work and patents related to adsorption through biomolecules like polysaccharides, polypeptides, lignin etc. and bio-sorption by biological material that are used for heavy metal removal. Biomolecules are cost effective and there have been significant progresses in the remediation of heavy metals but, still there are some problems that need to be rectified for its application at industrial processes.

  17. Ion-exchange behavior of alkali metals on treated carbons

    SciTech Connect

    Mohiuddin, G.; Hata, W.Y.; Tolan, J.S.

    1983-01-01

    The ion-exchange behavior of trace quantities of the alkali-metal ions sodium and cesium, on activated carbon impregnated with zirconium phosphate (referred to here as ZrP), was studied. Impregnated carbon had twice as much ion-exchange activity as unimpregnated, oxidized carbon, and 10 times as much as commercial activated carbons. The distribution coefficient of sodium increased with increasing pH; the distribution coefficient of cesium decreased with increasing pH. Sodium and cesium were separated with an electrolytic solution of 0.1 M HCl. Preliminary studies indicated that 0.2 M potassium and cesium can also be separated. Distribution coefficients of the supported ZrP were determined by the elution technique and agreed within 20% of the values for pure ZrP calculated from the literature.

  18. Superconductivity in the alkali metal intercalates of molybdenum disulphide

    NASA Technical Reports Server (NTRS)

    Somoano, R. B.; Hadek, V.; Rembaum, A.

    1972-01-01

    The complete series of alkali metals, lithium through cesium, have been intercalated into molybdenum disulphide, using both the liquid ammonia and vapor techniques. All the intercalates with the exception of lithium yielded full superconducting transitions with onset temperatures of 6 K for AxMoS2(Ax=K,Rb,Cs) and 4 K for BxMoS2(Bx=Li,Na). The superconducting transition for lithium was incomplete down to 1.5 K. Stoichiometries and unit cell parameters have been determined for the intercalation compounds. Both rhombohedral and hexagonal polymorphs of MoS2 have been intercalated and found to exhibit the same superconductivity behavior. The nature of the extraneous superconducting transition of some intercalated samples on exposure to air was elucidated.

  19. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan

    SciTech Connect

    1991-12-01

    Since 1987, Westinghouse Hanford Company has been a major contractor to the U.S. Department of Energy-Richland Operations Office and has served as co-operator of the 3718-F Alkali Metal Treatment and Storage Facility, the waste management unit addressed in this closure plan. The closure plan consists of a Part A Dangerous waste Permit Application and a RCRA Closure Plan. An explanation of the Part A Revision (Revision 1) submitted with this document is provided at the beginning of the Part A section. The closure plan consists of 9 chapters and 5 appendices. The chapters cover: introduction; facility description; process information; waste characteristics; groundwater; closure strategy and performance standards; closure activities; postclosure; and references.

  20. The effects of Pantoea sp.Y4-4 on alfalfa in the remediation of heavy-metal-contaminated soil and auxiliary impacts of plant residues on the remediation of saline alkali soils.

    PubMed

    Li, Shuhuan; Wang, Jie; Gao, Nanxiong; Liu, Lizhu; Chen, Yahua

    2016-11-30

    The plant growth-promoting rhizobacteria (PGPR) Y4-4 was isolated from plant rhizosphere soil and identified as Pantoea sp. by 16S rRNA sequence analysis. The effects of strain Y4-4 on alfalfa grew in heavy metals contaminated soil was investigated using a pot experiment. In Cu rich environment, the dry weight from shoot and total of plant inoculated with strain Y4-4 increased by 22.6% and 21%, and Cu accumulation increased by 15%. In Pb-Zn rich environment, the dry weight from shoot and total of plant inoculated with strain Y4-4 increased by 23.4% and 22%, and Zn accumulation increased by 30.3%. In addition, the salt tolerance and biomass of wheat seedling could be improved by applying strain Y4-4 mixed with plant residue as a result of Cu-rich plant residues provide copper nutrition wheat. This study offers an efficient PGPR with strong salt tolerance and a safe strategy for the post-treatment of plant residue.

  1. Heavy metals, islet function and diabetes development.

    PubMed

    Chen, Ya Wen; Yang, Ching Yao; Huang, Chun Fa; Hung, Dong Zong; Leung, Yuk Man; Liu, Shing Hwa

    2009-01-01

    It has long been believed that heavy metals possess many adverse health effects. Uncontrolled industrialization has released heavy metal pollution in the world. Heavy metal pollutants damage organ functions and disrupt physiological homeostasis. Diabetes mellitus is growing in prevalence worldwide. Several studies have indicated that the deficiency and efficiency of some essential trace metals may play a role in the islet function and development of diabetes mellitus. Some toxic metals have also been shown to be elevated in biological samples of diabetes mellitus patients. In the present work, we review the important roles of heavy metals in islet function and diabetes development in which the in vitro, in vivo or human evidences are associated with exposure to zinc, arsenic, cadmium, mercury and nickel. Through this work, we summarize the evidence which suggests that some heavy metals may play an important role in diabetes mellitus as environmental risk factors.

  2. Assessment of alkali metal coolants for the ITER blanket

    SciTech Connect

    Natesan, K.; Reed, C.B.; Mattas, R.F.

    1994-06-01

    The blanket system is one of the most important components of a fusion reactor because it has a major impact on both the economics and safety of fusion energy. The primary functions of the blanket in a deuterium/tritium-fueled fusion reactor are to convert the fusion energy into sensible heat and to breed tritium for the fuel cycle. The Blanket Comparison and Selection Study, conducted earlier, described the overall comparative performance of different blanket concepts, including liquid metal, molten salt, water and helium. This paper will discuss the ITER requirements for a self-cooled blanket concept with liquid lithium and for indirectly cooled concepts that use other alkali metals such as NaK. The paper addresses the thermodynamics of interactions between the liquid metals (e.g., lithium and NaK) and structural materials (e.g., V-base alloys), together with associated corrosion/compatibility issues. Available experimental data are used to assess the long-term performance of the first wall in a liquid metal environment. Other key issues include development of electrical insulator coatings on the first-wall structural material to MHD pressure drop, and tritium permeation/inventory in self-cooled and indirectly cooled concepts. Acceptable types of coatings (based on their chemical compatibility and physical properties) are identified, and surface-modification avenues to achieve these coatings on the first wall are discussed. The assessment examines the extent of our knowledge on structural materials performance in liquid metals and identifies needed research and development in several of the areas in order to establish performance envelopes for the first wall in a liquid-metal environment.

  3. Release characteristics of alkali and alkaline earth metallic species during biomass pyrolysis and steam gasification process.

    PubMed

    Long, Jiang; Song, Hu; Jun, Xiang; Sheng, Su; Lun-Shi, Sun; Kai, Xu; Yao, Yao

    2012-07-01

    Investigating the release characteristics of alkali and alkaline earth metallic species (AAEMs) is of potential interest because of AAEM's possible useful service as catalysts in biomass thermal conversion. In this study, three kinds of typical Chinese biomass were selected to pyrolyse and their chars were subsequently steam gasified in a designed quartz fixed-bed reactor to investigate the release characteristics of alkali and alkaline earth metallic species (AAEMs). The results indicate that 53-76% of alkali metal and 27-40% of alkaline earth metal release in pyrolysis process, as well as 12-34% of alkali metal and 12-16% of alkaline earth metal evaporate in char gasification process, and temperature is not the only factor to impact AAEMs emission. The releasing characteristics of AAEMs during pyrolysis and char gasification process of three kinds of biomass were discussed in this paper.

  4. Heavy metal uptake of Geosiphon pyriforme

    NASA Astrophysics Data System (ADS)

    Scheloske, Stefan; Maetz, Mischa; Schüßler, Arthur

    2001-07-01

    Geosiphon pyriforme represents the only known endosymbiosis between a fungus, belonging to the arbuscular mycorrhizal (AM) fungi, and cyanobacteria (blue-green algae). Therefore we use Geosiphon as a model system for the widespread AM symbiosis and try to answer some basic questions regarding heavy metal uptake or resistance of AM fungi. We present quantitative micro-PIXE measurements of a set of heavy metals (Cu, Cd, Tl, Pb) taken up by Geosiphon-cells. The uptake is studied as a function of the metal concentration in the nutrient solution and of the time Geosiphon spent in the heavy metal enriched medium. The measured heavy metal concentrations range from several ppm to some hundred ppm. Also the influence of the heavy metal uptake on the nutrition transfer of other elements will be discussed.

  5. Arbuscular mycorrhiza and heavy metal tolerance.

    PubMed

    Hildebrandt, Ulrich; Regvar, Marjana; Bothe, Hermann

    2007-01-01

    Arbuscular mycorrhizal fungi (AMF) have repeatedly been demonstrated to alleviate heavy metal stress of plants. The current manuscript summarizes results obtained to date on the colonization of plants by AMF in heavy metal soils, the depositions of heavy metals in plant and fungal structures and the potential to use AMF-plant combinations in phytoremediation, with emphasis on pennycresses (Thlaspi ssp.). The focus of this manuscript is to describe and discuss studies on the expression of genes in plants and fungi under heavy metal stress. The summary is followed by data on differential gene expression in extraradical mycelia (ERM) of in vitro cultured Glomus intraradices Sy167 supplemented with different heavy metals (Cd, Cu or Zn). The expression of several genes encoding proteins potentially involved in heavy metal tolerance varied in their response to different heavy metals. Such proteins included a Zn transporter, a metallothionein, a 90 kD heat shock protein and a glutathione S-transferase (all assignments of protein function are putative). Studies on the expression of the selected genes were also performed with roots of Medicago truncatula grown in either a natural, Zn-rich heavy metal "Breinigerberg" soil or in a non-polluted soil supplemented with 100 microM ZnSO(4). The transcript levels of the genes analyzed were enhanced up to eight fold in roots grown in the heavy metal-containing soils. The data obtained demonstrate the heavy metal-dependent expression of different AMF genes in the intra- and extraradical mycelium. The distinct induction of genes coding for proteins possibly involved in the alleviation of damage caused by reactive oxygen species (a 90 kD heat shock protein and a glutathione S-transferase) might indicate that heavy metal-derived oxidative stress is the primary concern of the fungal partner in the symbiosis.

  6. Alkali metal yttrium neo-pentoxide double alkoxide precursors to alkali metal yttrium oxide nanomaterials

    SciTech Connect

    Boyle, Timothy J.; Neville, Michael L.; Sears, Jeremiah Matthew; Cramer, Roger

    2016-03-15

    In this study, a series of alkali metal yttrium neo-pentoxide ([AY(ONep)4]) compounds were developed as precursors to alkali yttrium oxide (AYO2) nanomaterials. The reaction of yttrium amide ([Y(NR2)3] where R=Si(CH3)3) with four equivalents of H-ONep followed by addition of [A(NR2)] (A=Li, Na, K) or Ao (Ao=Rb, Cs) led to the formation of a complex series of AnY(ONep)3+n species, crystallographically identified as [Y2Li33-ONep)(μ3-HONep)(μ-ONep)5(ONep)3(HONep)2] (1), [YNa23-ONep)4(ONep)]2 (2), {[Y2K33-ONep)3(μ-ONep)4(ONep)2(ηξ-tol)2][Y4K24-O)(μ3-ONep)8(ONep)4]•ηx-tol]} (3), [Y4K24-O)(μ3-ONep)8(ONep)4] (3a), [Y2Rb34-ONep)3(μ-ONep)6] (4), and [Y2Cs46-O)(μ3-ONep)63-HONep)2(ONep)2x-tol)4]•tol (5). Compounds 1–5 were investigated as single source precursors to AYOx nanomaterials following solvothermal routes (pyridine, 185 °C for 24h). The final products after thermal processing were found by powder X-ray diffraction experiments to be Y2O3 with variable sized particles based on transmission electron diffraction. Energy dispersive X-ray spectroscopy studies indicated that the heavier alkali metal species were present in the isolated nanomaterials.

  7. (abstract) Alkali Metal Diffusion Through Porous Metal Electrodes in AMTEC Cells

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Jeffries-Nakamura, B.; Ryan, M. A.; Underwood, M. L.; O'Connor, D.; Kisor, A.; Kikkert, S.

    1993-01-01

    The mechanisms of mass transport of an alkali metal through porous metal electrodes in alkali metal thermal-to-electric converter AMTEC cells is important in optimizing these high current density devices, but also affords the opportunity to investigate a variety of simple mass transport modes at high temperatures via electrochemical techniques. We have previously reported evidence of ionic, free molecular flow, and surface transport of sodium in several types of AMTEC electrodes. Quantitative investigations of Na transport through WPt(sub 3.5) via surface or grain boundary diffusion, and K transport through porous Mo electrodes by free molecular flow, over large ranges of temperature have been performed. WPt(sub 3.5) has especially low transport impedance over the 950 to 1200K temperature range. New results are the Na through porous WPt(sub 3.5) and K through porous Mo diffusion rates and mechanisms.

  8. Coal combustion and heavy metals pollution

    SciTech Connect

    Danihelka, P.; Ochodek, T.; Borovec, K.

    1996-12-31

    Combustion of coal may be an important source of heavy metals pollution. The major environmental risks of heavy metals are connected to their toxicity and mobility in the environment. In the flame, heavy metals are re-distributed with respect to their volatility. Enrichment of fine particles by volatile metals is the most important mechanism for most of the metals. Nevertheless, Hg is emitted mainly in gaseous form and some metals like Mn are concentrated rather in coarse particles. Heavy metals pollution caused by emissions from combustion of coal may be decreased by fine particles removal; other possibilities (metals extraction from the coal, changes of condition in the flame) are limited. Fly ashes from the most important Czech power plants were examined with respect to the heavy metals content. The easily leachable elements with high volatility in the flame (arsenic, zinc, lead) were recognized as the most important fly ash pollutants. The average concentrations of these metals in fly ash were: bituminous coal 46{+-}18 ppm As, 196{+-}93 ppm Zn, 126{+-}46 ppm Pb; brown coal 283{+-}260 ppm As, 60{+-}28 ppm Pb and 212{+-}116 ppm Zn. When ESP and cyclones are used in series, fly ashes from ESP have higher concentration of volatile heavy metals, mainly Pb, Zn and As. Presence of chlorine in fuel increases the volatility of metals.

  9. Calculation of radiative corrections to E1 matrix elements in the neutral alkali metals

    SciTech Connect

    Sapirstein, J.; Cheng, K.T.

    2005-02-01

    Radiative corrections to E1 matrix elements for ns-np transitions in the alkali-metal atoms lithium through francium are evaluated. They are found to be small for the lighter alkali metals but significantly larger for the heavier alkali metals, and in the case of cesium much larger than the experimental accuracy. The relation of the matrix element calculation to a recent decay rate calculation for hydrogenic ions is discussed, and application of the method to parity nonconservation in cesium is described.

  10. Salt, Chlor-Alkali, and Related Heavy Chemicals

    NASA Astrophysics Data System (ADS)

    Bommaraju, Tilak V.

    The chemical category of inorganic salts encompasses many substances that dissociate completely in water, but only one salt, sodium chloride, is referred to by the common name, salt. Sodium chloride is ubiquitous in both its occurrence and its many uses. To date, there are over 14,000 uses for salt.1 Salt is used as a feedstock for many chemicals including chlorine, caustic soda (sodium hydroxide), synthetic soda ash (sodium carbonate), sodium chlorate, sodium sulfate, and metallic sodium. By indirect methods, sodium chloride is also used to produce hydrochloric acid and many other sodium salts. In its natural mineral form, salt may take on some color from some of the trace elements and other salts present, however, pure sodium chloride is a white to colorless crystalline substance, fairly soluble in water.2 Also known as halite, the substance is an essential nutrient to humans and animals for proper bodily functions.

  11. Method of treating alkali metal sulfide and carbonate mixtures

    DOEpatents

    Kohl, Arthur L.; Rennick, Robert D.; Savinsky, Martin W.

    1978-01-01

    A method of removing and preferably recovering sulfur values from an alkali metal sulfide and carbonate mixture comprising the steps of (1) introducing the mixture in an aqueous medium into a first carbonation zone and reacting the mixture with a gas containing a major amount of CO.sub.2 and a minor amount of H.sub.2 S; (2) introducing the resultant product from step 1 into a stripping zone maintained at subatmospheric pressure, and contacting this product with steam to produce a gaseous mixture, comprising H.sub.2 S and water vapor, and a liquor of reduced sulfide content; (3) introducing the liquor of reduced sulfide content into a second carbonation zone, and reacting the liquor with substantially pure gaseous CO.sub.2 in an amount sufficient to precipitate bicarbonate crystals and produce an offgas containing CO.sub.2 and H.sub.2 S for use in step 1; (4) recovering the bicarbonate crystals from step 3, and thermally decomposing the crystals to produce an alkaline metal carbonate product and a substantially pure CO.sub.2 offgas for use in step 3.

  12. Method and composition for testing for the presence of an alkali metal

    DOEpatents

    Guon, Jerold

    1981-01-01

    A method and composition for detecting the presence of an alkali metal on the surface of a body such as a metal plate, tank, pipe or the like is provided. The method comprises contacting the surface with a thin film of a liquid composition comprising a light-colored pigment, an acid-base indicator, and a nonionic wetting agent dispersed in a liquid carrier comprising a minor amount of water and a major amount of an organic solvent selected from the group consisting of the lower aliphatic alcohols, ketones and ethers. Any alkali metal present on the surface in elemental form or as an alkali metal hydroxide or alkali metal carbonate will react with the acid-base indicator to produce a contrasting color change in the thin film, which is readily discernible by visual observation or automatic techniques.

  13. Heavy Metal, Religiosity, and Suicide Acceptability.

    ERIC Educational Resources Information Center

    Stack, Steven

    1998-01-01

    Reports on data taken from the General Social Survey that found a link between "heavy metal" rock fanship and suicide acceptability. Finds that relationship becomes nonsignificant once level of religiosity is controlled. Heavy metal fans are low in religiosity, which contributes to greater suicide acceptability. (Author/JDM)

  14. Heavy Metal Music and Adolescent Suicidal Risk.

    ERIC Educational Resources Information Center

    Lacourse, Eric; Claes, Michel; Villeneuve, Martine

    2001-01-01

    Studied differentiating characteristics of youth who prefer heavy metal music, worship music, and use music for vicarious release. Data for 275 secondary school students suggest that heavy metal music preference and worshipping is not related to suicidal risk when controlling for other suicide factors. Discusses findings in the context of…

  15. Effect of heavy metals on soil fungi

    NASA Astrophysics Data System (ADS)

    Sosak-Świderska, Bożena

    2010-05-01

    Fungi constitute a high proportion of the microbial biomass in soil.Being widespread in soil their large surface-to-volume ratio and high metabolic activity, fungi can contribute significantly to heavy metal dynamics in soil. At neutral pH heavy metals in soils tend to be immobilized to precipitation and/or absorption to cation exchange sites of clay minerals. In the acidic soils, metals are more mobile and enter food webs easier. Microbial production of acids and chelating agents can mobilize to toxic metals. Mobilization is often by uptake and intracellular accumulation of the heavy metlas, and in this way, the bioavailability of metals towards other organisms can be more reduced. Fungi were isolated from soils from Upper Silesia in Poland and belonged to widespread genera: Aspergillus, Cladosporium, Penicillium and Trichoderma. Fungi from different taxonomic groups differ greatly in their tolerance to heavy metals. This could be related to their wall structure and chemistry as well as biochemical and physiological characteristics of fungi. Localization of metals in fungal cells was studied using electron microscopy analysis. Metal biosorption in the cell wall can be complex as melanin granules. Fungal vacuoles have an important role in the regulation of the cytosolic concentration of metal ions, and may contribute to heavy metal tolerance.In polluted soils with heavy metals, fungal species composition can be changed and their physiological activity can be changed, too.

  16. (abstract) Experimental and Modeling Studies of the Exchange Current at the Alkali Beta'-Alumina/Porous Electrode/Alkali Metal Vapor Three Phase Boundary

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Jeffries-Nakamura, B.; Ryan, M. A.; Underwood, M. L.; O'Connor, D.; Kikkert, S.

    1993-01-01

    The microscopic mechanism of the alkali ion-electron recombination reaction at the three phase boundary zone formed by a porous metal electrode in the alkali vapor on the surface of an alkali beta'-alumina solid electrolyte (BASE) ceramic has been studied by comparison of the expected rates for the three simplest reaction mechanisms with known temperature dependent rate data; and the physical parameters of typical porous metal electrode/BASE/alkali metal vapor reaction zones. The three simplest reactions are tunneling of electrons from the alkali coated electrode to a surface bound alkali metal ion; emission of an electron from the electrode with subsequent capture by a surface bound alkali metal ion; and thermal emission of an alkali cation from the BASE and its capture on the porous metal electrode surface where it may recombine with an electron. Only the first reaction adequately accounts for both the high observed rate and its temperature dependence. New results include crude modeling of simple, one step, three phase, solid/solid/gas electrochemical reaction.

  17. Is Electronegativity a Useful Descriptor for the "Pseudo-Alkali-Metal" NH4?

    SciTech Connect

    Whiteside, Alexander; Xantheas, Sotiris S.; Gutowski, Maciej S.

    2011-11-18

    Molecular ions in the form of "pseudo-atoms" are common structural motifs in chemistry, with properties that are transferrable between different compounds. We have determined the electronegativity of the "pseudo-alkali metal" ammonium (NH4) and evaluated its reliability as a descriptor in comparison to the electronegativities of the alkali metals. The computed properties of its binary complexes with astatine and of selected borohydrides confirm the similarity of NH4 to the alkali metal atoms, although the electronegativity of NH4 is relatively large in comparison to its cationic radius. We paid particular attention to the molecular properties of ammonium (angular anisotropy, geometric relaxation, and reactivity), which can cause deviations from the behaviour expected of a conceptual "true alkali metal" with this electronegativity. These deviations allow for the discrimination of effects associated with the polyatomic nature of NH4.

  18. Alkali Metal Thermal to Electric Converter (AMTEC) Technology Development for Potential Deep Space Scientific Missions

    NASA Technical Reports Server (NTRS)

    Mondt, J.; Sievers, R.

    1998-01-01

    This paper describes the alkali metal thermal to electric converter (AMTEC) technology development effort over the past year. The vapor-vapor AMTEC cell technology is being developed for use with either a solar or nuclear heat sources for space.

  19. Ab initio study of NMR shielding of alkali earth metal ions in water complexes and magnetic moments of alkali earth metal nuclei

    NASA Astrophysics Data System (ADS)

    Antušek, Andrej; Rodziewicz, Pawel; Keḑziera, Dariusz; Kaczmarek-Keḑziera, Anna; Jaszuński, Michał

    2013-11-01

    Ab initio calculations of NMR shielding constants of alkali earth metal ions in the series of water clusters are presented. The shielding constants for systems modeling the structure of the solvation layer of these ions are determined by adding to the coupled cluster singles-and-doubles (CCSD) results the calculated relativistic corrections. The relative magnitude of the dynamical effects, estimated for a typical solvated ion from Car-Parrinello molecular dynamics, is very small. The computed shielding constants are used next to obtain new values of the nuclear magnetic dipole moments of alkali earth metal nuclei.

  20. Process for preparing higher oxides of the alkali and alkaline earth metals

    NASA Technical Reports Server (NTRS)

    Sadhukhan, P.; Bell, A. (Inventor)

    1978-01-01

    High purity inorganic higher oxides of the alkali and alkaline earth metals are prepared by subjecting the hydroxide of the alkali and alkaline earth metal to a radio frequency discharge sustained in oxygen. The process is particulary adaptable to the production of high purity potassium superoxide by subjecting potassium hydroxide to glow discharge sustained in oxygen under the pressure of about 0.75 to 1.00 torr.

  1. Observation of Raman self-focusing in an alkali-metal vapor cell

    NASA Astrophysics Data System (ADS)

    Proite, N. A.; Unks, B. E.; Green, J. T.; Yavuz, D. D.

    2008-02-01

    We report an experimental demonstration of Raman self-focusing and self-defocusing in a far-off resonant alkali-metal atomic system. The key idea is to drive a hyperfine transition in an alkali-metal atom to a maximally coherent state with two laser beams. In this regime, the two-photon detuning from the Raman resonance controls the nonlinear index of the medium.

  2. The effect of different alkali metal hydroxides on nickel electrode life

    NASA Technical Reports Server (NTRS)

    Lim, H. S.; Verzwyvelt, S. A.; Clement, S. K.

    1988-01-01

    An accelerated cycle-life test (100-percent depth of discharge) of a sintered-type Ni electrode has been carried out in a flooded cell containing different alkali metal hydroxide electrolytes such as LiOH, NaOH, KOH, RbOH, and CsOH. Decrease in Ni electrode capacity with cycling was reduced as the radius of the alkali metal ions, with possible exception of CsOH.

  3. In situ formation of coal gasification catalysts from low cost alkali metal salts

    DOEpatents

    Wood, Bernard J.; Brittain, Robert D.; Sancier, Kenneth M.

    1985-01-01

    A carbonaceous material, such as crushed coal, is admixed or impregnated with an inexpensive alkali metal compound, such as sodium chloride, and then pretreated with a stream containing steam at a temperature of 350.degree. to 650.degree. C. to enhance the catalytic activity of the mixture in a subsequent gasification of the mixture. The treatment may result in the transformation of the alkali metal compound into another, more catalytically active, form.

  4. Stable alkali metal ion intercalation compounds as optimized metal oxide nanowire cathodes for lithium batteries.

    PubMed

    Zhao, Yunlong; Han, Chunhua; Yang, Junwei; Su, Jie; Xu, Xiaoming; Li, Shuo; Xu, Lin; Fang, Ruopian; Jiang, Hong; Zou, Xiaodong; Song, Bo; Mai, Liqiang; Zhang, Qingjie

    2015-03-11

    Intercalation of ions in electrode materials has been explored to improve the rate capability in lithium batteries and supercapacitors, due to the enhanced diffusion of Li(+) or electrolyte cations. Here, we describe a synergistic effect between crystal structure and intercalated ion by experimental characterization and ab initio calculations, based on more than 20 nanomaterials: five typical cathode materials together with their alkali metal ion intercalation compounds A-M-O (A = Li, Na, K, Rb; M = V, Mo, Co, Mn, Fe-P). Our focus on nanowires is motivated by general enhancements afforded by nanoscale structures that better sustain lattice distortions associated with charge/discharge cycles. We show that preintercalation of alkali metal ions in V-O and Mo-O yields substantial improvement in the Li ion charge/discharge cycling and rate, compared to A-Co-O, A-Mn-O, and A-Fe-P-O. Diffraction and modeling studies reveal that preintercalation with K and Rb ions yields a more stable interlayer expansion, which prevents destructive collapse of layers and allow Li ions to diffuse more freely. This study demonstrates that appropriate alkali metal ion intercalation in admissible structure can overcome the limitation of cyclability as well as rate capability of cathode materials, besides, the preintercalation strategy provides an effective method to enlarge diffusion channel at the technical level, and more generally, it suggests that the optimized design of stable intercalation compounds could lead to substantial improvements for applications in energy storage.

  5. Antiferromagnetic resonance in alkali-metal clusters in sodalite

    NASA Astrophysics Data System (ADS)

    Nakano, Takehito; Tsugeno, Hajime; Hanazawa, Atsufumi; Kashiwagi, Takanari; Nozue, Yasuo; Hagiwara, Masayuki

    2013-11-01

    We have performed electron spin resonance (ESR) studies of K43+ and (K3Rb)3+ nanoclusters incorporated in powder specimens of aluminosilicate sodalite at several microwave frequencies between 9 and 34 GHz. The K43+ and (K3Rb)3+ clusters are arrayed in a bcc structure and are known to show antiferromagnetic ordering below the Néel temperatures of TN ≃72 and ≃80 K, respectively, due to the exchange coupling between s electrons confined in the clusters. We have found sudden broadenings of ESR spectra in both samples below TN. The line shape of the spectra below TN is analyzed by powder pattern simulations of antiferromagnetic resonance (AFMR) spectra. The calculated line shapes well reproduce the experimental ones at all the frequencies by assuming a biaxial magnetic anisotropy. We have evaluated extremely small anisotropy fields of approximately 1 Oe indicating that these materials are ideal Heisenberg antiferromagnets. We have also found that the magnetic anisotropy changes from easy-plane type to uniaxial type by changing into a heavier alkali-metal cluster and that the g value shifts to a large value beyond two below TN for K43+ and (K3Rb)3+ nanoclusters. These novel features of K43+ and (K3Rb)3+ nanoclusters incorporated in sodalite are discussed.

  6. Optical Absorption of Alkali Metal Vapors at High Temperatures

    NASA Astrophysics Data System (ADS)

    Erdman, Paul Stephen

    High pressure, high temperature lithium vapors are of interest to both basic and applied research. Lithium vapors at extreme temperatures may contain new species of molecules and molecular ions which have not been previously observed or well studied. The strong optical absorption properties of alkali metals in the visible and infrared make them desirable as solar absorbing materials for many applications. In particular, lithium is being considered as a candidate for absorption of solar energy in solar plasma propulsion. Studies of lithium vapors under high pressure and at high temperatures would simulate the rocket thruster environment in which they are expected to perform as solar absorbers. Optical absorption experiments were performed on high temperature, high pressure lithium vapors. The Plasma Spectroscopy Cell (PSC), a unique device constructed just for such experiments, was used to heat lithium vapors to a maximum temperature of 2100 K at 1 atmosphere pressure. The PSC has the potential to reach 3000 K and 100 atmospheres. Absorption spectra contain features of several well understood molecular transitions of lithium. Remaining spectral features require modeling of all possible transitions in order to identify the molecule contributing to overall absorption. Modeling of lithium optical absorption is performed here for several transitions of diatomic lithium. Several interesting features of the PSC absorption spectra have been explained by the modeling. Additional experiments and modeling are possible for future research.

  7. Quantum magnetism with polar alkali-metal dimers

    SciTech Connect

    Gorshkov, Alexey V.; Manmana, Salvatore R.; Chen Gang; Demler, Eugene; Lukin, Mikhail D.; Rey, Ana Maria

    2011-09-15

    We show that dipolar interactions between ultracold polar alkali-metal dimers in optical lattices can be used to realize a highly tunable generalization of the t-J model, which we refer to as the t-J-V-W model. The model features long-range spin-spin interactions J{sub z} and J{sub perpendicular} of XXZ type, long-range density-density interaction V, and long-range density-spin interaction W, all of which can be controlled in both magnitude and sign independently of each other and of the tunneling t. The spin's is encoded in the rotational degree of freedom of the molecules, while the interactions are controlled by applied static electric and continuous-wave microwave fields. Furthermore, we show that nuclear spins of the molecules can be used to implement an additional (orbital) degree of freedom that is coupled to the original rotational degree of freedom in a tunable way. The presented system is expected to exhibit exotic physics and to provide insights into strongly correlated phenomena in condensed-matter systems. Realistic experimental imperfections are discussed.

  8. Removal of oxides from alkali metal melts by reductive titration to electrical resistance-change end points

    DOEpatents

    Tsang, Floris Y.

    1980-01-01

    Alkali metal oxides dissolved in alkali metal melts are reduced with soluble metals which are converted to insoluble oxides. The end points of the reduction is detected as an increase in electrical resistance across an alkali metal ion-conductive membrane interposed between the oxide-containing melt and a material capable of accepting the alkali metal ions from the membrane when a difference in electrical potential, of the appropriate polarity, is established across it. The resistance increase results from blocking of the membrane face by ions of the excess reductant metal, to which the membrane is essentially non-conductive.

  9. Alkali Metal Variation and Twisting of the FeNNFe Core in Bridging Diiron Dinitrogen Complexes.

    PubMed

    McWilliams, Sean F; Rodgers, Kenton R; Lukat-Rodgers, Gudrun; Mercado, Brandon Q; Grubel, Katarzyna; Holland, Patrick L

    2016-03-21

    Alkali metal cations can interact with Fe-N2 complexes, potentially enhancing back-bonding or influencing the geometry of the iron atom. These influences are relevant to large-scale N2 reduction by iron, such as in the FeMoco of nitrogenase and the alkali-promoted Haber-Bosch process. However, to our knowledge there have been no systematic studies of a large range of alkali metals regarding their influence on transition metal-dinitrogen complexes. In this work, we varied the alkali metal in [alkali cation]2[LFeNNFeL] complexes (L = bulky β-diketiminate ligand) through the size range from Na(+) to K(+), Rb(+), and Cs(+). The FeNNFe cores have similar Fe-N and N-N distances and N-N stretching frequencies despite the drastic change in alkali metal cation size. The two diketiminates twist relative to one another, with larger dihedral angles accommodating the larger cations. In order to explain why the twisting has so little influence on the core, we performed density functional theory calculations on a simplified LFeNNFeL model, which show that the two metals surprisingly do not compete for back-bonding to the same π* orbital of N2, even when the ligand planes are parallel. This diiron system can tolerate distortion of the ligand planes through compensating orbital energy changes, and thus, a range of ligand orientations can give very similar energies.

  10. On the origin of alkali metals in Europa exosphere

    NASA Astrophysics Data System (ADS)

    Ozgurel, Ozge; Pauzat, Françoise; Ellinger, Yves; Markovits, Alexis; Mousis, Olivier; LCT, LAM

    2016-10-01

    At a time when Europa is considered as a plausible habitat for the development of an early form of life, of particular concern is the origin of neutral sodium and potassium atoms already detected in its exosphere (together with magnesium though in smaller abundance), since these atoms are known to be crucial for building the necessary bricks of prebiotic species. However their origin and history are still poorly understood. The most likely sources could be exogenous and result from the contamination produced by Io's intense volcanism and/or by meteoritic bombardment. These sources could also be endogenous if these volatile elements originate directly from Europa's icy mantle. Here we explore the possibility that neutral sodium and potassium atoms were delivered to the satellite's surface via the upwelling of ices formed in contact with the hidden ocean. These metallic elements would have been transferred as ions to the ocean at early epochs after Europa's formation, by direct contact of water with the rocky core. During Europa's subsequent cooling, the icy layers formed at the top of the ocean would have kept trapped the sodium and potassium, allowing their future progression to the surface and final identification in the exosphere of the satellite. To support this scenario, we have used chemistry numerical models based on first principle periodic density functional theory (DFT). These models are shown to be well adapted to the description of compact ice and are capable to describe the trapping and neutralization of the initial ions in the ice matrix. The process is found relevant for all the elements considered, alkali metals like Na and K, as well as for Mg and probably for Ca, their respective abundances depending essentially of their solubility and chemical capabilities to blend with water ices.

  11. Half metallic ferromagnetism in alkali metal nitrides MN (M = Rb, Cs): A first principles study

    SciTech Connect

    Murugan, A. Rajeswarapalanichamy, R. Santhosh, M. Sudhapriyanga, G.; Kanagaprabha, S.

    2014-04-24

    The structural, electronic and elastic properties of two alkali metal nitrides (MN: M= Rb, Cs) are investigated by the first principles calculations based on density functional theory using the Vienna ab-initio simulation package. At ambient pressure the two nitrides are stable in ferromagnetic state with CsCl structure. The calculated lattice parameters are in good agreement with the available results. The electronic structure reveals that these materials are half metallic in nature. A pressure-induced structural phase transition from CsCl to ZB phase is observed in RbN and CsN.

  12. Coulomb explosion during the early stages of the reaction of alkali metals with water.

    PubMed

    Mason, Philip E; Uhlig, Frank; Vaněk, Václav; Buttersack, Tillmann; Bauerecker, Sigurd; Jungwirth, Pavel

    2015-03-01

    Alkali metals can react explosively with water and it is textbook knowledge that this vigorous behaviour results from heat release, steam formation and ignition of the hydrogen gas that is produced. Here we suggest that the initial process enabling the alkali metal explosion in water is, however, of a completely different nature. High-speed camera imaging of liquid drops of a sodium/potassium alloy in water reveals submillisecond formation of metal spikes that protrude from the surface of the drop. Molecular dynamics simulations demonstrate that on immersion in water there is an almost immediate release of electrons from the metal surface. The system thus quickly reaches the Rayleigh instability limit, which leads to a 'coulomb explosion' of the alkali metal drop. Consequently, a new metal surface in contact with water is formed, which explains why the reaction does not become self-quenched by its products, but can rather lead to explosive behaviour.

  13. Bimolecular gas-phase exchange of alkali metals between cationized biomolecules and neutral crown ethers

    SciTech Connect

    Pope, M.; Dearden, D.V.; Hofstadler, S.

    1995-12-31

    Electrospray ionization of polypeptides and nucleic acids often yields ions containing sodium or potassium charge carriers. These alkali adducts are frequently the residue of ionic buffers used to preserve protein conformation in solution or artifacts of a natural matrix such as blood plasma. Measures taken in solution to desalinate these samples are hindered by the desire to maintain native conformation. The authors here show that ion-molecule chemistry is an alternate means of removing alkali metal ions from multiply-charged biomolecules. Ion-molecule reactions of multiply charged polypeptides with crown ethers result in adduction of the crown if protons are the only charge bearing species, or desalting if alkali metals are among the charge carriers. Both product ions, the desalted peptide and the crown/alkali metal complex, are observed in the latter case.

  14. Method for inhibiting alkali metal corrosion of nickel-containing alloys

    DOEpatents

    DeVan, Jackson H.; Selle, James E.

    1983-01-01

    Structural components of nickel-containing alloys within molten alkali metal systems are protected against corrosion during the course of service by dissolving therein sufficient aluminum, silicon, or manganese to cause the formation and maintenance of a corrosion-resistant intermetallic reaction layer created by the interaction of the molten metal, selected metal, and alloy.

  15. Alkali Metal Variation and Twisting of the FeNNFe Core in Bridging Diiron Dinitrogen Complexes

    PubMed Central

    2016-01-01

    Alkali metal cations can interact with Fe–N2 complexes, potentially enhancing back-bonding or influencing the geometry of the iron atom. These influences are relevant to large-scale N2 reduction by iron, such as in the FeMoco of nitrogenase and the alkali-promoted Haber–Bosch process. However, to our knowledge there have been no systematic studies of a large range of alkali metals regarding their influence on transition metal–dinitrogen complexes. In this work, we varied the alkali metal in [alkali cation]2[LFeNNFeL] complexes (L = bulky β-diketiminate ligand) through the size range from Na+ to K+, Rb+, and Cs+. The FeNNFe cores have similar Fe–N and N–N distances and N–N stretching frequencies despite the drastic change in alkali metal cation size. The two diketiminates twist relative to one another, with larger dihedral angles accommodating the larger cations. In order to explain why the twisting has so little influence on the core, we performed density functional theory calculations on a simplified LFeNNFeL model, which show that the two metals surprisingly do not compete for back-bonding to the same π* orbital of N2, even when the ligand planes are parallel. This diiron system can tolerate distortion of the ligand planes through compensating orbital energy changes, and thus, a range of ligand orientations can give very similar energies. PMID:26925968

  16. Note: An ion source for alkali metal implantation beneath graphene and hexagonal boron nitride monolayers on transition metals

    SciTech Connect

    Lima, L. H. de; Cun, H. Y.; Hemmi, A.; Kälin, T.; Greber, T.

    2013-12-15

    The construction of an alkali-metal ion source is presented. It allows the acceleration of rubidium ions to an energy that enables the penetration through monolayers of graphene and hexagonal boron nitride. Rb atoms are sublimated from an alkali-metal dispenser. The ionization is obtained by surface ionization and desorption from a hot high work function surface. The ion current is easily controlled by the temperature of ionizer. Scanning Tunneling Microscopy measurements confirm ion implantation.

  17. Review of alkali metal and refractory alloy compatibility for Rankine cycle applications

    SciTech Connect

    DiStefano, J.R. )

    1989-01-01

    The principal corrosion mechanisms in refractory metal-alkali systems are dissolution, mass transfer, and impurity reactions. In general, niobium, tantalum, molybdenum, and tungsten have low solubilities in the alkali metals, even to very high temperatures, and static corrosion studies have verified that the systems are basically compatible. Loop studies with niobium and tantalum based alloys do not indicate any serious problems due to temperature gradient mass transfer. Above 1000 K, dissimilar metal mass transfer is noted between the refractory metals and iron or nickel based alloys. The most serious corrosion problems encountered are related to impurity reactions associated with oxygen.

  18. Heavy metal contamination from geothermal sources.

    PubMed Central

    Sabadell, J E; Axtmann, R C

    1975-01-01

    Liquid-dominated hydrothermal reservoirs, which contain saline fluids at high temperatures and pressures, have a significant potential for contamination of the environment by heavy metals. The design of the power conversion cycle in a liquid-dominated geothermal plant is a key factor in determining the impact of the installation. Reinjection of the fluid into the reservoir minimizes heavy metal effluents but is routinely practiced at few installations. Binary power cycles with reinjection would provide even cleaner systems but are not yet ready for commercial application. Vapor-dominated systems, which contain superheated steam, have less potential for contamination but are relatively uncommon. Field data on heavy metal effluents from geothermal plants are sparse and confounded by contributions from "natural" sources such as geysers and hot springs which often exist nearby. Insofar as geothermal power supplies are destined to multiply, much work is required on their environmental effects including those caused by heavy metals. PMID:1227849

  19. Removal of heavy metals from waste streams

    SciTech Connect

    Spence, M.D.; Kozaruk, J.M.; Melvin, M.; Gardocki, S.M.

    1988-07-19

    A method for removing heavy metals from effluent water is described comprising performing sequentially the following steps: (a) adding from 7-333 ppm of an anionic surfactant to the effluent water to provide coagulatable heavy metal ion; (b) adjusting the effluent water pH to within the range of 8 to 10, (c) providing from 10-200 ppm of a cationic coagulant to coagulate the heavy metal ion, (d) providing from 0.3 to 5.0 ppm of a polymeric flocculant whereby a heavy metal containing floc is formed for removal from the effluent water, and, (e) then removing the floc from the effluent water, wherein the anionic surfactant is sodium lauryl ether sulfate. The cationic coagulant is selected from the group consisting of diallyl dimethylammonium chloride polymer, epichlorohydrin dimethylamine polymer, ethylene amine polymer, polyaluminum chloride, and alum; and the flocculant is an acrylamide/sodium acrylate copolymer having an RSV greater than 23.

  20. Hydrogen Adsorption by Alkali Metal Graphite Intercalation Compounds

    NASA Astrophysics Data System (ADS)

    Purewal, Justin

    Adsorption occurs whenever a solid surface is exposed to a gas or liquid, and is characterized by an increase in fluid density near the interface. Adsorbents have drawn attention in the current effort to engineer materials that store hydrogen at high densities within moderate temperature and pressure regimes. Carbon adsorbents are a logical choice as a storage material due to their low costs and large surface areas. Unfortunately, carbon adsorbents suffer from a low binding enthalpy for H2 (about 5 kJ mol-1), well below the 15 to 18 kJ mol-1) that is considered optimal for hydrogen storage systems. Binding interactions can be increased by the following methods: (1) adjusting the graphite interplanar separation with a pillared structure, and (2) introducing dopant species that interact with H2 molecules by strong electrostatic forces. Graphite intercalation compounds are a class of materials that contain both pillared structures and chemical dopants, making them an excellent model system for studying the fundamentals of hydrogen adsorption in nanostructured carbons. Pressure-composition-temperature diagrams of the MC24(H 2)x graphite intercalation compounds were measured for M = (K, Rb, Cs). Adsorption enthalpies were measured as a function of H2 concentration. Notably, CsC24 had an average adsorption enthalpy of 14.9 kJ mol-1), nearly three times larger than that of pristine graphite. The adsorption enthalpies were found to be positively correlated with the alkali metal size. Adsorption capacities were negatively correlated with the size of the alkali metal. The rate of adsorption is reduced at large H2 compositions, due to the effects of site-blocking and correlation on the H2 diffusion. The strong binding interaction and pronounced molecular-sieving behavior of KC24 is likely to obstruct the translational diffusion of adsorbed H2 molecules. In this work, the diffusion of H2 adsorbed in KC24 was studied by quasielastic neutron scattering measurements and molecular

  1. Heavy metals and living systems: An overview

    PubMed Central

    Singh, Reena; Gautam, Neetu; Mishra, Anurag; Gupta, Rajiv

    2011-01-01

    Heavy metals are natural constituents of the earth's crust, but indiscriminate human activities have drastically altered their geochemical cycles and biochemical balance. This results in accumulation of metals in plant parts having secondary metabolites, which is responsible for a particular pharmacological activity. Prolonged exposure to heavy metals such as cadmium, copper, lead, nickel, and zinc can cause deleterious health effects in humans. Molecular understanding of plant metal accumulation has numerous biotechnological implications also, the long term effects of which might not be yet known. PMID:21713085

  2. Heavy metal removal and recovery using microorganisms

    SciTech Connect

    Wilde, E.W. ); Benemann, J.R. , Pinole, CA )

    1991-02-01

    Microorganisms -- bacteria, fungi, and microalgae -- can accumulate relatively large amounts of toxic heavy metals and radionuclides from the environment. These organisms often exhibit specificity for particular metals. The metal content of microbial biomass can be a substantial fraction of total dry weight with concentration factors (metal in dry biomass to metal in solution) exceeding one million in some cases. Both living and inert (dead) microbial biomass can be used to reduce heavy metal concentrations in contaminated waters to very low levels -- parts per billion and even lower. In many respects (e.g. specificity, residual metal concentrations, accumulation factors, and economics) microbial bioremoval processes can be superior to conventional processes, such as ion exchange and caustic (lime or hydroxide) precipitation for heavy metals removal from waste and contaminated waters. Thus, bioremoval could be developed to contribute to the clean-up of wastes at the Savannah River Site (SRS) and other DOE facilities. However, the potential advantages of bioremoval processes must still be developed into practical operating systems. A detailed review of the literature suggests that appropriate bioremoval processes could be developed for the SRS. There is great variability from one biomass source to another in bioremoval capabilities. Bioremoval is affected by pH, other ions, temperature, and many other factors. The biological (living vs. dead) and physical (immobilized vs. dispersed) characteristics of the biomass also greatly affect metal binding. Even subtle differences in the microbial biomass, such as the conditions under which it was cultivated, can have major effects on heavy metal binding.

  3. Simultaneous removal of nitrate and heavy metals by iron metal.

    PubMed

    Hao, Zhi-Wei; Xu, Xin-Hua; Jin, Jian; He, Ping; Liu, Yong; Wang, Da-Hui

    2005-05-01

    Great attention should be paid now to simultaneously removing common pollutants, especially inorganic pollutants such as nitrate and heavy metals, as individual removal has been investigated extensively. Removing common pollutants simultaneously by iron metal is a very effective alternative method. Near neutral pH, heavy metals, such as copper and nickel, can be removed rapidly by iron metal, while nitrate removal very much slower than that of copper and nickel, and copper can accelerate nitrate removal when both are removed simultaneously. Even a little amount of copper can enhance nitrate removal efficiently. Different mechanisms of these contaminants removal by iron metal were also discussed.

  4. Advances in high temperature components for AMTEC (Alkali Metal Thermal-to-Electric Converter)

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Jeffries-Nakamura, B.; Underwood, M. L.; Ryan, M. A.; O'Connor, D.; Kikkert, S.

    1991-01-01

    The basic performance of Alkali Metal Thermal-to-Electric Converter (AMTEC) cells is well understood, and quantitative modeling of the electrode performance has been carried out. Tests have been carried out to evaluate the high temperature performance of critical AMTEC components. Progress made in understanding the relative performance of AMTEC components, such as electrodes, electrolytes, working fluids, and seals, as device operating temperature is varied is discussed. Most metallic components are especially subject to corrosion in hot liquid alkali metals containing dissolved oxides. Stability issues of AMTEC components may be addressed by life testing, accelerated testing, and modeling based on known kinetic and thermochemical data.

  5. Progress in High-Field Optical Pumping of Alkali Metal Nuclei

    NASA Astrophysics Data System (ADS)

    Patton, B.; Ishikawa, K.; Jau, Y.-Y.; Happer, W.

    2006-05-01

    We present preliminary results of an attempt to polarize alkali metal nuclei via optical pumping in a large (9.4-tesla) magnetic field. NMR measurements of ^87Rb and ^133Cs films in optical cells will be reported. Depopulation pumping of alkalis can easily produce electron polarizations of order unity, as measured during spin-exchange optical pumping of noble gases [1]. At low magnetic fields (< ˜1 kG), the strong hyperfine coupling between the alkali electron and nucleus allows angular momentum exchange from one to the other, resulting in nuclear polarization enhancement through optical pumping. In the high magnetic fields required for NMR, however, this interaction is largely decoupled and electron-nuclear spin exchange must rely upon the δA I .S interaction induced by buffer gas collisions (also called the ``Carver rate''). High-field optical pumping experiments may allow for a more precise measurement of this rate, as well as yielding insight into the transfer of angular momentum from the polarized alkali vapor to the bulk alkali metal on the cell walls. The technical challenges of high-resolution NMR of alkali metals at 9.4 tesla will be discussed. 1. E. Babcock, I. Nelson, S. Kadlecek, et al., Physical Review Letters 91, 123003 (2003).

  6. Annihilation of positrons trapped at the alkali-metal-covered transition-metal surface

    SciTech Connect

    Fazleev, N.G.; Fry, J.L.; Kuttler, K.H.; Koymen, A.R.; Weiss, A.H.

    1995-08-15

    Recent studies of the Cu(100) surface covered with submonolayers of Cs revealed that the normalized intensity of the positron-annihilation-induced Cu {ital M}{sub 2,3}{ital VV} Auger signal remains nearly constant at the clean Cu(100) surface value until the Cs coverage reaches approximately 0.7 physical monolayer, at which coverage the signal intensity drops precipitously. We present a microscopic analysis of this unusual behavior of the Cu {ital M}{sub 2,3}{ital VV} Auger signal based on a treatment of a positron as a single charged particle trapped in a ``correlation well`` in the proximity of the surface atoms. The image-potential-induced positron surface states are calculated using the corrugated-mirror model in a full three-dimensional geometry. These states are studied for the clean Cu(100) surface and for various ordered structures of the Cs adsorbate on the Cu(100) surface below and above the critical alkali-metal coverage of approximately 0.7 physical monolayer. Calculations show that whereas the positron surface state is localized in the region of the Cs/Cu(100) interface for Cs coverages below the critical alkali-metal coverage, at a Cs coverage corresponding to one physical monolayer the positron surface state is localized on the vacuum side of the Cs overlayer. The probabilities for a positron trapped in a surface state to annihilate with relevant Cu and Cs core-level electrons as well as the positron surface-state lifetimes are computed for various alkali-metal structures on the Cu(100) surface and compared with experimental positron-annihilation-induced Auger-electron-spectroscopy data. It is shown that a shift in localization of the positron surface state from the Cs/Cu(100) interface to the vacuum side of the alkali-metal overlayer results in a sharp decrease in the positron-annihilation probabilities with Cu 3{ital s} and 3{ital p} core-level electrons, in agreement with experiment.

  7. ANALYSIS OF HEAVY METALS IN STORMWATER

    EPA Science Inventory

    Stormwater sampling for colloidal and dissolved metals and organic carbon has been initiated at six outfalls draining locally-designated, nonindustrial land uses in Monmouth County, NJ. Of the heavy metals, only Cu and Zn were found in all samples, mostly in dissolved form. Large...

  8. Prediction of Heavy Metal Uptake by Marsh Plants Based on Chemical Extraction of Heavy Metals from Dredged Material.

    DTIC Science & Technology

    1978-02-01

    A field and laboratory study was conducted to establish the extent of heavy metal absorption and uptake by marsh plant species from dredged material...emphasizes the need for a method to predict heavy metal availability from dredged material to plants. DTPA extraction of heavy metals gave the best correlations with actual heavy metal concentrations in marsh plants.

  9. Dissolution Process of Palladium in Hydrochloric Acid: A Route via Alkali Metal Palladates

    NASA Astrophysics Data System (ADS)

    Kasuya, Ryo; Miki, Takeshi; Morikawa, Hisashi; Tai, Yutaka

    2015-12-01

    To improve the safety of the Pd recovery processes that use toxic oxidizers, dissolution of Pd in hydrochloric acid with alkali metal palladates was investigated. Alkali metal palladates were prepared by calcining a mixture of Pd black and alkali metal (Li, Na, and K) carbonates in air. Almost the entire amount of Pd was converted into Li2PdO2 after calcination at 1073 K (800 °C) using Li2CO3. In contrast, PdO was obtained by calcination at 1073 K (800 °C) using Na and K carbonates. Our results indicated that Li2CO3 is the most active reagent among the examined alkali metal carbonates for the formation of palladates. In addition, dissolution of the resulting Li2PdO2 in HCl solutions was evaluated under various conditions. In particular, Li2PdO2 rapidly dissolved in diluted (0.1 M) HCl at ambient temperature. Solubility of Pd of Li2PdO2 was found to be 99 pct or larger after dissolution treatment at 353 K (80 °C) for 5 minutes; in contrast, PdO hardly dissolved in 0.1 M HCl. The dissolution mechanism of Li2PdO2 in HCl was also elucidated by analysis of crystal structures and particulate properties. Since our process is completely free from toxic oxidizers, the dissolution process via alkali metal palladates is much safer than currently employed methods.

  10. Saturated vapor pressure above the amalgam of alkali metals in discharge lamps

    NASA Astrophysics Data System (ADS)

    Gavrish, S. V.

    2011-12-01

    A theoretical and numerical analysis of the evaporation process of two-component compounds in vapors of alkali metals in discharge lamps is presented. Based on the developed mathematical model of calculation of saturated vapor pressure of the metal above the amalgam, dependences of mass fractions of the components in the discharge volume on design parameters and thermophysical characteristics of the lamp are obtained.

  11. The heavy metal subculture and suicide.

    PubMed

    Stack, S; Gundlach, J; Reeves, J L

    1994-01-01

    The impact of the heavy metal music subculture on suicide has been the subject of much public debate but little scholarly research. The present paper assesses this relationship with data on heavy metal magazine subscriptions and youth suicide in the 50 states. We find that, controlling for other predictors of suicide, the greater the strength of the metal subculture, the higher the youth suicide rate. The music perhaps nurtures suicidal tendencies already present in the subculture. The model explains 51% of the variance in youth suicide.

  12. Alkali Metal Backup Cooling for Stirling Systems - Experimental Results

    NASA Technical Reports Server (NTRS)

    Schwendeman, Carl; Tarau, Calin; Anderson, William G.; Cornell, Peggy A.

    2013-01-01

    In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 degC temperature increase from the nominal vapor temperature. The 19 degC temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental

  13. Alkali Metal Backup Cooling for Stirling Systems - Experimental Results

    NASA Technical Reports Server (NTRS)

    Schwendeman, Carl; Tarau, Calin; Anderson, William G.; Cornell, Peggy A.

    2013-01-01

    In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 C temperature increase from the nominal vapor temperature. The 19 C temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental

  14. Heavy Metal Poisoning and Cardiovascular Disease

    PubMed Central

    Alissa, Eman M.; Ferns, Gordon A.

    2011-01-01

    Cardiovascular disease (CVD) is an increasing world health problem. Traditional risk factors fail to account for all deaths from CVD. It is mainly the environmental, dietary and lifestyle behavioral factors that are the control keys in the progress of this disease. The potential association between chronic heavy metal exposure, like arsenic, lead, cadmium, mercury, and CVD has been less well defined. The mechanism through which heavy metals act to increase cardiovascular risk factors may act still remains unknown, although impaired antioxidants metabolism and oxidative stress may play a role. However, the exact mechanism of CVD induced by heavy metals deserves further investigation either through animal experiments or through molecular and cellular studies. Furthermore, large-scale prospective studies with follow up on general populations using appropriate biomarkers and cardiovascular endpoints might be recommended to identify the factors that predispose to heavy metals toxicity in CVD. In this review, we will give a brief summary of heavy metals homeostasis, followed by a description of the available evidence for their link with CVD and the proposed mechanisms of action by which their toxic effects might be explained. Finally, suspected interactions between genetic, nutritional and environmental factors are discussed. PMID:21912545

  15. Structural resolution of 4-substituted proline diastereomers with ion mobility spectrometry via alkali metal ion cationization.

    PubMed

    Flick, Tawnya G; Campuzano, Iain D G; Bartberger, Michael D

    2015-03-17

    The chirality of substituents on an amino acid can significantly change its mode of binding to a metal ion, as shown here experimentally by traveling wave ion mobility spectrometry-mass spectrometry (TWIMS-MS) of different proline isomeric molecules complexed with alkali metal ions. Baseline separation of the cis- and trans- forms of both hydroxyproline and fluoroproline was achieved using TWIMS-MS via metal ion cationization (Li(+), Na(+), K(+), and Cs(+)). Density functional theory calculations indicate that differentiation of these diastereomers is a result of the stabilization of differing metal-complexed forms adopted by the diastereomers when cationized by an alkali metal cation, [M + X](+) where X = Li, Na, K, and Cs, versus the topologically similar structures of the protonated molecules, [M + H](+). Metal-cationized trans-proline variants exist in a linear salt-bridge form where the metal ion interacts with a deprotonated carboxylic acid and the proton is displaced onto the nitrogen atom of the pyrrolidine ring. In contrast, metal-cationized cis-proline variants adopt a compact structure where the carbonyl of the carboxylic acid, nitrogen atom, and if available, the hydroxyl and fluorine substituent solvate the metal ion. Experimentally, it was observed that the resolution between alkali metal-cationized cis- and trans-proline variants decreases as the size of the metal ion increases. Density functional theory demonstrates that this is due to the decreasing stability of the compact charge-solvated cis-proline structure with increased metal ion radius, likely a result of steric hindrance and/or weaker binding to the larger metal ion. Furthermore, the unique structures adopted by the alkali metal-cationized cis- and trans-proline variants results in these molecules having significantly different quantum mechanically calculated dipole moments, a factor that can be further exploited to improve the diastereomeric resolution when utilizing a drift gas with a

  16. Enhancing Skin Permeation of Biphenylacetic Acid (BPA) Using Salt Formation with Organic and Alkali Metal Bases

    PubMed Central

    Pawar, Vijay; Naik, Prashant; Giridhar, Rajani; Yadav, Mange Ram

    2015-01-01

    In the present study, a series of organic and alkali metal salts of biphenylacetic acid (BPA) have been prepared and evaluated in vitro for percutaneous drug delivery. The physicochemical properties of BPA salts were determined using solubility measurements, DSC, and IR. The DSC thermogram and FTIR spectra confirmed the salt formation with organic and alkali metal bases. Among the series, salts with organic amines (ethanolamine, diethanolamine, triethanolamine, and diethylamine) had lowered melting points while the alkali metal salt (sodium) had a higher melting point than BPA. The in vitro study showed that salt formation improves the physicochemical properties of BPA, leading to improved permeability through the skin. Amongst all the prepared salts, ethanolamine salt (1b) showed 7.2- and 5.4-fold higher skin permeation than the parent drug at pH 7.4 and 5.0, respectively, using rat skin. PMID:26839810

  17. Elliptical polarization of near-resonant linearly polarized probe light in optically pumped alkali metal vapor

    NASA Astrophysics Data System (ADS)

    Li, Yingying; Wang, Zhiguo; Jin, Shilong; Yuan, Jie; Luo, Hui

    2017-02-01

    Optically pumped alkali metal atoms currently provide a sensitive solution for magnetic microscopic measurements. As the most practicable plan, Faraday rotation of linearly polarized light is extensively used in spin polarization measurements of alkali metal atoms. In some cases, near-resonant Faraday rotation is applied to improve the sensitivity. However, the near-resonant linearly polarized probe light is elliptically polarized after passing through optically pumped alkali metal vapor. The ellipticity of transmitted near-resonant probe light is numerically calculated and experimentally measured. In addition, we also analyze the negative impact of elliptical polarization on Faraday rotation measurements. From our theoretical estimate and experimental results, the elliptical polarization forms an inevitable error in spin polarization measurements.

  18. Elliptical polarization of near-resonant linearly polarized probe light in optically pumped alkali metal vapor

    PubMed Central

    Li, Yingying; Wang, Zhiguo; Jin, Shilong; Yuan, Jie; Luo, Hui

    2017-01-01

    Optically pumped alkali metal atoms currently provide a sensitive solution for magnetic microscopic measurements. As the most practicable plan, Faraday rotation of linearly polarized light is extensively used in spin polarization measurements of alkali metal atoms. In some cases, near-resonant Faraday rotation is applied to improve the sensitivity. However, the near-resonant linearly polarized probe light is elliptically polarized after passing through optically pumped alkali metal vapor. The ellipticity of transmitted near-resonant probe light is numerically calculated and experimentally measured. In addition, we also analyze the negative impact of elliptical polarization on Faraday rotation measurements. From our theoretical estimate and experimental results, the elliptical polarization forms an inevitable error in spin polarization measurements. PMID:28216649

  19. Structural and Magnetic Diversity in Alkali-Metal Manganate Chemistry: Evaluating Donor and Alkali-Metal Effects in Co-complexation Processes.

    PubMed

    Uzelac, Marina; Borilovic, Ivana; Amores, Marco; Cadenbach, Thomas; Kennedy, Alan R; Aromí, Guillem; Hevia, Eva

    2016-03-24

    By exploring co-complexation reactions between the manganese alkyl Mn(CH2SiMe3)2 and the heavier alkali-metal alkyls M(CH2SiMe3) (M=Na, K) in a benzene/hexane solvent mixture and in some cases adding Lewis donors (bidentate TMEDA, 1,4-dioxane, and 1,4-diazabicyclo[2,2,2] octane (DABCO)) has produced a new family of alkali-metal tris(alkyl) manganates. The influences that the alkali metal and the donor solvent impose on the structures and magnetic properties of these ates have been assessed by a combination of X-ray, SQUID magnetization measurements, and EPR spectroscopy. These studies uncover a diverse structural chemistry ranging from discrete monomers [(TMEDA)2 MMn(CH2SiMe3)3] (M=Na, 3; M=K, 4) to dimers [{KMn(CH2SiMe3)3 ⋅C6 H6}2] (2) and [{NaMn(CH2SiMe3)3}2 (dioxane)7] (5); and to more complex supramolecular networks [{NaMn(CH2SiMe3)3}∞] (1) and [{Na2Mn2 (CH2SiMe3)6 (DABCO)2}∞] (7)). Interestingly, the identity of the alkali metal exerts a significant effect in the reactions of 1 and 2 with 1,4-dioxane, as 1 produces coordination adduct 5, while 2 forms heteroleptic [{(dioxane)6K2Mn2 (CH2SiMe3)4(O(CH2)2OCH=CH2)2}∞] (6) containing two alkoxide-vinyl anions resulting from α-metalation and ring opening of dioxane. Compounds 6 and 7, containing two spin carriers, exhibit antiferromagnetic coupling of their S=5/2 moments with varying intensity depending on the nature of the exchange pathways.

  20. Structural Diversity in Alkali Metal and Alkali Metal Magnesiate Chemistry of the Bulky 2,6‐Diisopropyl‐N‐(trimethylsilyl)anilino Ligand

    PubMed Central

    Fuentes, M. Ángeles; Zabala, Andoni; Kennedy, Alan R.

    2016-01-01

    Abstract Bulky amido ligands are precious in s‐block chemistry, since they can implant complementary strong basic and weak nucleophilic properties within compounds. Recent work has shown the pivotal importance of the base structure with enhancement of basicity and extraordinary regioselectivities possible for cyclic alkali metal magnesiates containing mixed n‐butyl/amido ligand sets. This work advances alkali metal and alkali metal magnesiate chemistry of the bulky arylsilyl amido ligand [N(SiMe3)(Dipp)]− (Dipp=2,6‐iPr2‐C6H3). Infinite chain structures of the parent sodium and potassium amides are disclosed, adding to the few known crystallographically characterised unsolvated s‐block metal amides. Solvation by N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine (PMDETA) or N,N,N′,N′‐tetramethylethylenediamine (TMEDA) gives molecular variants of the lithium and sodium amides; whereas for potassium, PMDETA gives a molecular structure, TMEDA affords a novel, hemi‐solvated infinite chain. Crystal structures of the first magnesiate examples of this amide in [MMg{N(SiMe3)(Dipp)}2(μ‐nBu)]∞ (M=Na or K) are also revealed, though these breakdown to their homometallic components in donor solvents as revealed through NMR and DOSY studies. PMID:27573676

  1. Structural Diversity in Alkali Metal and Alkali Metal Magnesiate Chemistry of the Bulky 2,6-Diisopropyl-N-(trimethylsilyl)anilino Ligand.

    PubMed

    Fuentes, M Ángeles; Zabala, Andoni; Kennedy, Alan R; Mulvey, Robert E

    2016-10-10

    Bulky amido ligands are precious in s-block chemistry, since they can implant complementary strong basic and weak nucleophilic properties within compounds. Recent work has shown the pivotal importance of the base structure with enhancement of basicity and extraordinary regioselectivities possible for cyclic alkali metal magnesiates containing mixed n-butyl/amido ligand sets. This work advances alkali metal and alkali metal magnesiate chemistry of the bulky arylsilyl amido ligand [N(SiMe3 )(Dipp)](-) (Dipp=2,6-iPr2 -C6 H3 ). Infinite chain structures of the parent sodium and potassium amides are disclosed, adding to the few known crystallographically characterised unsolvated s-block metal amides. Solvation by N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) or N,N,N',N'-tetramethylethylenediamine (TMEDA) gives molecular variants of the lithium and sodium amides; whereas for potassium, PMDETA gives a molecular structure, TMEDA affords a novel, hemi-solvated infinite chain. Crystal structures of the first magnesiate examples of this amide in [MMg{N(SiMe3 )(Dipp)}2 (μ-nBu)]∞ (M=Na or K) are also revealed, though these breakdown to their homometallic components in donor solvents as revealed through NMR and DOSY studies.

  2. Laboratory measurements of alkali metal containing vapors released during biomass combustion

    SciTech Connect

    Dayton, D.C.; Milne, T.A.

    1996-12-31

    Alkali metals, in particular potassium, have been implicated as key ingredients for enhancing fouling and slagging of heat transfer surfaces in power generating facilities that convert biomass to electricity. When biomass is used as a fuel in boilers, the deposits formed reduce efficiency, and in the worst case lead to unscheduled plant downtime. Blending biomass with other fuels is often used as a strategy to control fouling and slagging problems. Depending on the combustor, sorbents can be added to the fuel mixture to sequester alkali metals. Another possibility is to develop methods of hot gas cleanup that reduce the amount of alkali vapor to acceptable levels. These solutions to fouling and slagging, however, would greatly benefit from a detailed understanding of the mechanisms of alkali release during biomass combustion. Identifying these alkali vapor species and understanding how these vapors enhance deposit formation would also be beneficial. The approach is to directly sample the hot gases liberated from the combustion of small biomass samples in a variable-temperature quartz-tube reactor employing a molecular beam mass spectrometer (MBMS) system. The authors have successfully used this experimental technique to identify alkali species released during the combustion of selected biomass feedstocks used in larger scale combustion facilities. Fuels investigated include lodgepole pine, eucalyptus, poplar, corn stover, switchgrass, wheat straw, rice straw, pistachio shells, almond shells and hulls, wood wastes, waste paper, alfalfa stems, and willow tops.

  3. Ternary Amides Containing Transition Metals for Hydrogen Storage: A Case Study with Alkali Metal Amidozincates.

    PubMed

    Cao, Hujun; Richter, Theresia M M; Pistidda, Claudio; Chaudhary, Anna-Lisa; Santoru, Antonio; Gizer, Gökhan; Niewa, Rainer; Chen, Ping; Klassen, Thomas; Dornheim, Martin

    2015-11-01

    The alkali metal amidozincates Li4 [Zn(NH2)4](NH2)2 and K2[Zn(NH2)4] were, to the best of our knowledge, studied for the first time as hydrogen storage media. Compared with the LiNH2-2 LiH system, both Li4 [Zn(NH2)4](NH2)2-12 LiH and K2[Zn(NH2)4]-8 LiH systems showed improved rehydrogenation performance, especially K2[Zn(NH2)4]-8 LiH, which can be fully hydrogenated within 30 s at approximately 230 °C. The absorption properties are stable upon cycling. This work shows that ternary amides containing transition metals have great potential as hydrogen storage materials.

  4. Community Heavy Metal Exposure, San Francisco, California

    NASA Astrophysics Data System (ADS)

    Chavez, A.; Devine, M.; Ho, T.; Zapata, I.; Bissell, M.; Neiss, J.

    2008-12-01

    Heavy metals are natural elements that generally occur in minute concentrations in the earth's crust. While some of these elements, in small quantities, are vital to life, most are harmful in larger doses. Various industrial and agricultural processes can result in dangerously high concentrations of heavy metals in our environment. Consequently, humans can be exposed to unsafe levels of these elements via the air we breathe, the water and food we consume, and the many products we use. During a two week study we collected numerous samples of sediments, water, food, and household items from around the San Francisco Bay Area that represent industrial, agricultural, and urban/residential settings. We analyzed these samples for Mercury (Hg), Lead (Pb), and Arsenic (As). Our goal was to examine the extent of our exposure to heavy metals in our daily lives. We discovered that many of the common foods and materials in our lives have become contaminated with unhealthy concentrations of these metals. Of our food samples, many exceeded the EPA's Maximum Contaminant Levels (MCL) set for each metal. Meats (fish, chicken, and beef) had higher amounts of each metal than did non-meat items. Heavy metals were also prevalent in varying concentrations in the environment. While many of our samples exceeded the EPA's Sediment Screening Level (SSL) for As, only two other samples surpassed the SSL set for Pb, and zero of our samples exceeded the SSL for Hg. Because of the serious health effects that can result from over-exposure to heavy metals, the information obtained in this study should be used to influence our future dietary and recreational habits.

  5. Advances in high temperature components for AMTEC (alkali metal thermal-to-electric converter)

    SciTech Connect

    Williams, R.M.; Jeffries-Nakamura, B.; Underwood, M.L.; Ryan, M.A.; O'Connor, D.; Kikkert, S.

    1991-01-01

    Long lifetimes are required for AMTEC (or sodium heat engine) components for aerospace and terrestrial applications, and the high heat input temperature as well as the alkali metal liquid and vapor environment places unusual demands on the materials used to construct AMTEC devices. In addition, it is important to maximize device efficiency and power density, while maintaining a long life capability. In addition to the electrode, which must provide both efficient electrode kinetics, transport of the alkali metal, and low electrical resistance, other high temperature components of the cell face equally demanding requirements. The beta{double prime} alumina solid electrolyte (BASE), the seal between the BASE ceramic and its metallic transition to the hot alkali metal (liquid or vapor) source, and metallic components of the device are exposed to hot liquid alkali metal. Modification of AMTEC components may also be useful in optimizing the device for particular operating conditions. In particular, a potassium AMTEC may be expected to operate more efficiently at lower temperatures.

  6. Advances in high temperature components for AMTEC (alkali metal thermal-to-electric converter)

    SciTech Connect

    Williams, R.M.; Jeffries-Nakamura, B.; Underwood, M.L.; Ryan, M.A.; O`Connor, D.; Kikkert, S.

    1991-12-31

    Long lifetimes are required for AMTEC (or sodium heat engine) components for aerospace and terrestrial applications, and the high heat input temperature as well as the alkali metal liquid and vapor environment places unusual demands on the materials used to construct AMTEC devices. In addition, it is important to maximize device efficiency and power density, while maintaining a long life capability. In addition to the electrode, which must provide both efficient electrode kinetics, transport of the alkali metal, and low electrical resistance, other high temperature components of the cell face equally demanding requirements. The beta{double_prime} alumina solid electrolyte (BASE), the seal between the BASE ceramic and its metallic transition to the hot alkali metal (liquid or vapor) source, and metallic components of the device are exposed to hot liquid alkali metal. Modification of AMTEC components may also be useful in optimizing the device for particular operating conditions. In particular, a potassium AMTEC may be expected to operate more efficiently at lower temperatures.

  7. Tune-out wavelengths of alkali-metal atoms and their applications

    SciTech Connect

    Arora, Bindiya; Safronova, M. S.; Clark, Charles W.

    2011-10-15

    Using first-principles calculations, we identify ''tune-out'' optical wavelengths, {lambda}{sub zero}, for which the ground-state frequency-dependent polarizabilities of alkali-metal atoms vanish. Our approach uses high-precision, relativistic all-order method in which all single, double, and partial triple excitations of the Dirac-Fock wave functions are included to all orders of perturbation theory. We discuss the use of tune-out wavelengths for sympathetic cooling in two-species mixtures of alkali metals with group II and other elements of interest. Special cases in which these wavelengths coincide with strong resonance transitions in a target system are identified.

  8. Adsorption of alkali metals and their effect on electronic properties of grain boundaries in bulk of polycrystalline silicon

    SciTech Connect

    Olimov, L. O.

    2010-05-15

    The adsorption of alkali metals and their effect on the electronic properties of grain boundaries in bulk of polycrystalline silicon has been studied experimentally. The results obtained show that the potential barrier grows during diffusion and adsorption of alkali metal atoms along grain boundaries.

  9. Structural differences of metal biphenylenebisphosphonate with change in the alkali metal

    SciTech Connect

    Kinnibrugh, Tiffany L.; Garcia, Nancy; Clearfield, Abraham

    2012-03-15

    A series of monovalent biphenylenebisphosphonates have been prepared using hydrothermal synthesis resulting in a composition M[HO{sub 3}PC{sub 12}H{sub 8}PO{sub 3}H{sub 2}] where M=Li{sup +}, Na{sup +}, K{sup +}, Rb{sup +}, and Cs{sup +}. Three of the original four phosphonic acid protons are retained, making the compounds Broensted acids. A synthesis using microwave irradiation results in a new compound, Na{sub 2}(HO{sub 3}PC{sub 12}H{sub 8}PO{sub 3}H), where only two protons are retained. Two structural types were found for the three-dimensional compounds where one type has a continuous inorganic layer. In the other structural type, the inorganic layer is formed by hydrogen bonding between neighboring chains. These structural variations arise as the coordination number changes from 4 for lithium to 8 for cesium without change in composition. The dense packing of the biphenylenebisphosphonate restricts the access to the protons, thus these compounds cannot be used as Broensted acid catalysts. Alternatively, addition of N,N-dimethylformamide to the reaction mixture results in inclusion of ammonium ions in the cavities. - Graphical abstract: Two of five metal biphenylenebisphosphonate structures (lithium (a) and cesium (b)) are presented. Each compound is a potential Bronsted acid catalyst, where three of the original four protons are retained from the biphenylenebisphosphonic acid. Highlights: Black-Right-Pointing-Pointer Alkali phosphonates are Broensted acids with the retention of three protons per alkali cation. Black-Right-Pointing-Pointer These compounds are thermally stable to approximately 300 Degree-Sign C. Black-Right-Pointing-Pointer A new structure was formed from the in situ synthesis with dimethylformamide as a reactant. Black-Right-Pointing-Pointer With lack of access to the protons the alkali phosphonates cannot function as a Bronsted acid catalysts.

  10. Transfer of heavy metals through terrestrial food webs: a review.

    PubMed

    Gall, Jillian E; Boyd, Robert S; Rajakaruna, Nishanta

    2015-04-01

    Heavy metals are released into the environment by both anthropogenic and natural sources. Highly reactive and often toxic at low concentrations, they may enter soils and groundwater, bioaccumulate in food webs, and adversely affect biota. Heavy metals also may remain in the environment for years, posing long-term risks to life well after point sources of heavy metal pollution have been removed. In this review, we compile studies of the community-level effects of heavy metal pollution, including heavy metal transfer from soils to plants, microbes, invertebrates, and to both small and large mammals (including humans). Many factors contribute to heavy metal accumulation in animals including behavior, physiology, and diet. Biotic effects of heavy metals are often quite different for essential and non-essential heavy metals, and vary depending on the specific metal involved. They also differ for adapted organisms, including metallophyte plants and heavy metal-tolerant insects, which occur in naturally high-metal habitats (such as serpentine soils) and have adaptations that allow them to tolerate exposure to relatively high concentrations of some heavy metals. Some metallophyte plants are hyperaccumulators of certain heavy metals and new technologies using them to clean metal-contaminated soil (phytoextraction) may offer economically attractive solutions to some metal pollution challenges. These new technologies provide incentive to catalog and protect the unique biodiversity of habitats that have naturally high levels of heavy metals.

  11. Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

    DOEpatents

    Doeff, M.M.; Peng, M.Y.; Ma, Y.; Visco, S.J.; DeJonghe, L.C.

    1996-09-24

    An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M{sub x}Z{sub y}Mn{sub (1{minus}y)}O{sub 2}, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell. 11 figs.

  12. Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

    DOEpatents

    Doeff, Marca M.; Peng, Marcus Y.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard C.

    1996-01-01

    An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M.sub.x Z.sub.y Mn.sub.(1-y) O.sub.2, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell.

  13. Solvent- and catalyst-free mechanochemical synthesis of alkali metal monohydrides

    SciTech Connect

    Hlova, Ihor Z.; Castle, Andra; Goldston, Jennifer F.; Gupta, Shalabh; Prost, Timothy; Kobayashi, Takeshi; Scott Chumbley, L.; Pruski, Marek; Pecharsky, Vitalij K.

    2016-07-06

    Alkali metal monohydrides, AH (A = Li–Cs) have been synthesized in quantitative yields at room temperature by reactive milling of alkali metals in the presence of hydrogen gas at 200 bar or less. The mechanochemical approach reported here eliminates problems associated with the malleability of alkali metals — especially Li, Na, and K — and promotes effective solid–gas reactions, ensuring their completion. This is achieved by incorporating a certain volume fraction of the corresponding hydride powder as a process control agent, which allows continuous and efficient milling primarily by coating the surface of metal particles, effectively blocking cold welding. Formation of high-purity crystalline monohydrides has been confirmed by powder X-ray diffraction, solid-state NMR spectroscopy, and volumetric analyses of reactively desorbed H2 from as-milled samples. The proposed synthesis method is scalable and particularly effective for extremely air-sensitive materials, such as alkali and alkaline earth metal hydrides. Furthermore, the technique may also be favorable for production in continuous reactors operating at room temperature, thereby reducing the total processing time, energy consumption and, hence, the cost of production of these hydrides or their derivatives and composites.

  14. Solvent- and catalyst-free mechanochemical synthesis of alkali metal monohydrides

    DOE PAGES

    Hlova, Ihor Z.; Castle, Andra; Goldston, Jennifer F.; ...

    2016-07-06

    Alkali metal monohydrides, AH (A = Li–Cs) have been synthesized in quantitative yields at room temperature by reactive milling of alkali metals in the presence of hydrogen gas at 200 bar or less. The mechanochemical approach reported here eliminates problems associated with the malleability of alkali metals — especially Li, Na, and K — and promotes effective solid–gas reactions, ensuring their completion. This is achieved by incorporating a certain volume fraction of the corresponding hydride powder as a process control agent, which allows continuous and efficient milling primarily by coating the surface of metal particles, effectively blocking cold welding. Formationmore » of high-purity crystalline monohydrides has been confirmed by powder X-ray diffraction, solid-state NMR spectroscopy, and volumetric analyses of reactively desorbed H2 from as-milled samples. The proposed synthesis method is scalable and particularly effective for extremely air-sensitive materials, such as alkali and alkaline earth metal hydrides. Furthermore, the technique may also be favorable for production in continuous reactors operating at room temperature, thereby reducing the total processing time, energy consumption and, hence, the cost of production of these hydrides or their derivatives and composites.« less

  15. Heavy metal, religiosity, and suicide acceptability.

    PubMed

    Stack, S

    1998-01-01

    There has been little work at the national level on the subject of musical subcultures and suicide acceptability. The present work explores the link between "heavy metal" rock fanship and suicide acceptability. Metal fanship is thought to elevate suicide acceptability through such means as exposure to a culture of personal and societal chaos marked by hopelessness, and through its associations with demographic risk factors such as gender, socioeconomic status, and education. Data are taken from the General Social Survey. A link between heavy metal fanship and suicide acceptability is found. However, this relationship becomes nonsignificant once level of religiosity is controlled. Metal fans are low in religiosity, which contributes, in turn, to greater suicide acceptability.

  16. Effect of the alkali metal activator on the properties of fly ash-based geopolymers

    SciTech Connect

    Jaarsveld, J.G.S. van; Deventer, J.S.J. van

    1999-10-01

    The alkali and alkali earth metal cations present during the formation of most known aluminosilicate structures have a very significant effect on both the physical and chemical properties of the final product. Geopolymers are no exception, although this effect has not been thoroughly quantified and in the case of waste-based geopolymers it has not received any significant attention. The present study investigates the effect of mainly Na{sup +} and K{sup +} on the physical and chemical properties of fly ash-based geopolymeric binders both before and after setting has occurred. A variety of tests were conducted, including rheological measurements, various leaching tests, compressive strength testing, specific surface area determinations, and infrared spectroscopy (IR). It is concluded that the alkali metal cation controls and affects almost all stages of geopolymerization, from the ordering of ions and soluble species during the dissolution process to playing a structure-directing role during gel hardening and eventual crystal formation.

  17. IUPAC-NIST Solubility Data Series. 79. Alkali and Alkaline Earth Metal Pseudohalides

    NASA Astrophysics Data System (ADS)

    Hála, Jiri

    2004-03-01

    This volume presents solubility data of azides, cyanides, cyanates, and thiocyanates of alkali metals, alkaline earth metals, and ammonium. Covered are binary and ternary systems in all solvents. No solubility data have been found for some of the compounds of alkali metals, alkaline metals, and ammonium. These include beryllium and magnesium azides, lithium, rubidium cesium, ammonium, and alkaline earth cyanates and cyanides, and beryllium thiocyanate. Likewise, no solubility data seem to exist for selenocyanates of the mentioned metals and ammonium. The literature has been covered up to the middle of 2001, and there was a great effort to have the literature survey as complete as possible. The few documents which remained unavailable to the editor, and could not be included in the volume, are listed in the Appendix. For some compounds it was not possible to show the Chemical Abstracts registry numbers since these have not been assigned. For this reason, the registry number index is incomplete.

  18. PROCESS FOR SEPARATION OF HEAVY METALS

    DOEpatents

    Duffield, R.B.

    1958-04-29

    A method is described for separating plutonium from aqueous acidic solutions of neutron-irradiated uranium and the impurities associated therewith. The separation is effected by adding, to the solution containing hexavalent uranium and plutonium, acetate ions and the ions of an alkali metal and those of a divalent metal and thus forming a complex plutonium acetate salt which is carried by the corresponding complex of uranium, such as sodium magnesium uranyl acetate. The plutonium may be separated from the precipitated salt by taking the same back into solution, reducing the plutonium to a lower valent state on reprecipitating the sodium magnesium uranyl salt, removing the latter, and then carrying the plutonium from ihe solution by means of lanthanum fluoride.

  19. Near-threshold photodetachment of heavy alkali-metal anions

    SciTech Connect

    Bahrim, C.; Thumm, U.; Khuskivadze, A.A.; Fabrikant, I.I.

    2002-11-01

    We calculate near-threshold photodetachment cross sections for Rb{sup -}, Cs{sup -}, and Fr{sup -} using the Pauli equation method with a model potential describing the effective electron-atom interaction. Parameters of the model potential are fitted to reproduce ab initio scattering phase shifts obtained from Dirac R-matrix calculations. Special care is taken to formulate the boundary conditions near the atomic nucleus for solving the Pauli equation, based on the analytic solution of the Dirac equation for a Coulomb potential. We find a {sup 3}P{sub 1}{sup o} resonance contribution to the photodetachment cross section of Rb{sup -}, Cs{sup -}, and Fr{sup -} ions. Our calculated total photodetachment cross sections for Cs agree with experiments after tuning the resonance position by 2.4 meV. For Rb{sup -} and Fr{sup -} the resonance contribution is much smaller than for Cs. We therefore also provide angle-differential cross sections and asymmetry parameters which are much more sensitive to the resonant contribution than total cross sections.

  20. Hydroponics reducing effluent's heavy metals discharge.

    PubMed

    Rababah, Abdellah; Al-Shuha, Ahmad

    2009-01-01

    This paper investigates the capacity of Nutrient Film Technique (NFT) to control effluent's heavy metals discharge. A commercial hydroponic system was adapted to irrigate lettuces with primary treated wastewater for studying the potential heavy metals removal. A second commercial hydroponic system was used to irrigate the same type of lettuces with nutrient solution and this system was used as a control. Results showed that lettuces grew well when irrigated with primary treated effluent in the commercial hydroponic system. The NFT-plant system heavy metals removal efficiency varied amongst the different elements, The system's removal efficiency for Cr was more than 92%, Ni more than 85%, in addition to more than 60% reduction of B, Pb, and Zn. Nonetheless, the NFT-plants system removal efficiencies for As, Cd and Cu were lower than 30%. Results show that lettuces accumulated heavy metals in leaves at concentrations higher than the maximum acceptable European and Australian levels. Therefore, non-edible plants such as flowers or pyrethrum are recommended as value added crops for the proposed NFT.

  1. ANALYSIS OF HEAVY METALS IN STORMWATER

    EPA Science Inventory

    Sampling has been undertaken to determine the concentrations of heavy metals, both particle-associated and dissolved, in stormwater from several storm sewer outfalls in Monmouth County, NJ. This project is ongoing in concert with coordinated studies of pathogen and nutrient input...

  2. Heavy Metals and Related Trace Elements.

    ERIC Educational Resources Information Center

    Leland, Harry V.; And Others

    1978-01-01

    Presents a literature review of heavy metals and related trace elements in the environment, covering publications of 1976-77. This review includes: (1) trace treatment in natural water and in sediments; and (2) bioaccumulation and toxicity of trace elements. A list of 466 references is presented. (HM)

  3. Surface phonons on Al(111) surface covered by alkali metals

    NASA Astrophysics Data System (ADS)

    Rusina, G. G.; Eremeev, S. V.; Borisova, S. D.; Sklyadneva, I. Yu.; Chulkov, E. V.

    2005-06-01

    We investigated the vibrational and structural properties of the Al(111)-(3×3)R30°-AM (AM=Na,K,Li) adsorbed systems using interaction potentials from the embedded-atom method. The surface relaxation, surface phonon dispersion, and polarization of vibrational modes for the alkali adatoms and the substrate atoms as well as the local density of states are discussed. Our calculated structural parameters are in close agreement with experimental and ab initio results. The obtained vibrational frequencies compare fairly well with the available experimental data.

  4. Synthetic, structural, and theoretical investigations of alkali metal germanium hydrides--contact molecules and separated ions.

    PubMed

    Teng, Weijie; Allis, Damian G; Ruhlandt-Senge, Karin

    2007-01-01

    The preparation of a series of crown ether ligated alkali metal (M=K, Rb, Cs) germyl derivatives M(crown ether)nGeH3 through the hydrolysis of the respective tris(trimethylsilyl)germanides is reported. Depending on the alkali metal and the crown ether diameter, the hydrides display either contact molecules or separated ions in the solid state, providing a unique structural insight into the geometry of the obscure GeH3- ion. Germyl derivatives displaying M--Ge bonds in the solid state are of the general formula [M([18]crown-6)(thf)GeH3] with M=K (1) and M=Rb (4). The compounds display an unexpected geometry with two of the GeH3 hydrogen atoms closely approaching the metal center, resulting in a partially inverted structure. Interestingly, the lone pair at germanium is not pointed towards the alkali metal, rather two of the three hydrides are approaching the alkali metal center to display M--H interactions. Separated ions display alkali metal cations bound to two crown ethers in a sandwich-type arrangement and non-coordinated GeH3- ions to afford complexes of the type [M(crown ether)2][GeH3] with M=K, crown ether=[15]crown-5 (2); M=K, crown ether=[12]crown-4 (3); and M=Cs, crown ether=[18]crown-6 (5). The highly reactive germyl derivatives were characterized by using X-ray crystallography, 1H and 13C NMR, and IR spectroscopy. Density functional theory (DFT) and second-order Møller-Plesset perturbation theory (MP2) calculations were performed to analyze the geometry of the GeH3- ion in the contact molecules 1 and 4.

  5. Enhancing electrocatalytic hydrogen evolution by nickel salicylaldimine complexes with alkali metal cations in aqueous media.

    PubMed

    Shao, Haiyan; Muduli, Subas K; Tran, Phong D; Soo, Han Sen

    2016-02-18

    New salicylaldimine nickel complexes, comprising only earth-abundant elements, have been developed for electrocatalytic hydrogen evolution in aqueous media. The second-sphere ether functionalities on the periphery of the complexes enhance the electrocatalytic activity in the presence of alkali metal cations. The electrocatalysts demonstrate improved performances especially in the economical and sustainable seawater reaction medium.

  6. Potential Energy Curves and Associated Line Shape of Alkali-Metal and Noble-Gas Interactions

    DTIC Science & Technology

    2014-10-20

    xii I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Motivation...150 xii POTENTIAL ENERGY CURVES AND ASSOCIATED LINE SHAPE OF ALKALI-METAL AND NOBLE-GAS INTERACTIONS I. Introduction 1.1 Motivation...starting point for all modern developments of a quantum picture of pressure broadening, and show how this theory reduces to the classical theory under

  7. Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

    DOEpatents

    Cassano, Anthony A.

    1985-01-01

    A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs.

  8. Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

    DOEpatents

    Cassano, A.A.

    1985-07-02

    A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs. 3 figs.

  9. The Alkali Metal Thermal-To-Electric Converter for Solar System Exploration

    NASA Technical Reports Server (NTRS)

    Ryan, M.

    1999-01-01

    AMTEC, the Alkali Metal Thermal to Electric Converter, is a direct thermal to electric energy conversion device; it has been demostrated to perform at high power densities, with open circuit voltages in single electrochemical cells up to 1.6 V and current desities up to 2.0 A/cm(sup 2).

  10. Heavy metals in the environment

    SciTech Connect

    Storm, G.L.; Fosmire, G.J.; Bellis, E.D.

    1994-05-01

    Concentration (Cd, Pb, Zn, and Cu) in soil and wildlife at the Palmerton zinc smelter site in eastern Pennsylvania were determined 6 yr after zinc smelting was terminated in 1980. Levels of the four metals were higher in litter (01 and 02 horizon) than in soil (A1 horizon), and the metals were at or near levels when the smelters were still in operation. Levels of metals in sod weft highest at sites close to the smelters and decreased as distances from the smelters increased. The relation of decreasing amounts of metals in body tissues with increasing distance from the smelters also held true for amphibians and mammals. An exception to this relation was higher level of Cu in red-lacked salamanders (Plethodon cinereus) captured {approx}17 km downwind than those captured {approx}12 km downwind. Levels of Zn, Pb, and Co in liver, kidney, and muscle tissue of white-footed mice (Peromyscus leucopus) were not different (P >0.05) among sites. Cadmium in kidneys in white-footed mice exceeded 10 mg&& which is reportedly considered an indication of environmental contamination. Levels of Cd in kidneys and liver of white-tailed deer (Odocoileus virginianus) at Palmerton were five times higher than those for white-tailed deer collected 180 km southwest of Palmerton in southcentral Pennsylvania. The abnormal amounts of metals in the tissues of terrestrial vertebrates, and the absence or low abundance of wildlife at Palmerton indicated that ecological processes within 5 km of the smelters were markedly influenced 6 yr after zinc smelting was discontinued. 41 refs., 5 figs., 4 tabs.

  11. The interactions of sorbates with gallosilicates and alkali-metal exchanged gallosilicates

    NASA Astrophysics Data System (ADS)

    Limtrakul, J.; Kuno, M.; Treesukol, P.

    1999-11-01

    Structures, energetics and vibrational frequencies of the interaction of adsorbates with H-aluminosilicates (H-AlZ), H-gallosilicates (H-GaZ), alkali-metal exchanged aluminosilicates (X-AlZ) and alkali-metal exchanged gallosilicates (X-GaZ), where X being Li, Na, or K, have been carried out at B3LYP and HF levels of theory with 6-31G(d) as the basis set. The charge compensating alkali-metal ions can affect the catalytically active site (Si-O-T where T=Al or Ga) by weakening the Si-O, Al-O, and Ga-O bonds as compared to their anionic frameworks. Comparing the net stabilization energies, Δ ENSE, of the naked alkali-metal/H 2O adducts with those of the alkali-metal exchanged zeolite/H 2O systems, the latter amounts only to about 50% of the former, which is partly due to the destabilizing role of the negative zeolitic oxygen frameworks surrounding the cations. The interaction of sorbates with the alkali-metal exchanged gallosilicates can be employed to probe the field strength inside the catalytic frameworks as indicated by the plot of the binding energy, Δ E, versus 1/ RX-O w2, with R(X-O w) being the distance between the cationic nucleus and the oxygen atom of the adsorbate. The IR spectra of H 2O adsorbed on Na-AlZ are calculated to be 3584, 3651, and 1686 cm -1. The obtained results are in excellent agreement with the very recent experimental IR spectra of water adsorbed on Na-ZSM-5 of Zecchina et al. (J. Phys. Chem., 100 (1996) 16 484). Other important features, i.e. the correlation between Δ νOH and, Δ E, R(X-O w) , and 1/ RX-O w2, cationic size, demonstrate that the interactions of sorbates with alkali-metal exchanged gallosilicates are well approximated by electrostatic contribution.

  12. How composting affects heavy metal content

    SciTech Connect

    Canarutto, S.; Petruzzelli, G.; Lubrano, L.; Guidi, G.V.

    1991-06-01

    This paper describes ways in which a properly conducted composting process can alter the chemical forms of heavy metals and consequently the quality of the compost. This process is of particular interest in the Italian policy of waste management due to the low level of organic matter in Italian agricultural soils. Results of the studies show that the proper process of compost maturation seems to increase the concentrations of humic acids with respect to those of fulvic acids. These variations in the quantity and quality of humic substances influence the speciation of heavy metals with a large part of the metals complexed and reaching the soil in a less mobile form. The distribution of copper, cadmium, zinc, nickel, lead and chromium among humic fractions is compared in two composting procedures.

  13. Heavy metal fates in laboratory bioretention systems.

    PubMed

    Sun, Xueli; Davis, Allen P

    2007-01-01

    Key to managing heavy metals in bioretention is to understand their fates in bioretention facilities. In this study, pot prototypes filled with bioretention media were built to simulate the conditions of natural growth of plants. Synthetic runoff with different heavy metal loadings (copper, cadmium, lead, and zinc) was periodically applied. Metal accumulations in tissues of grasses -Panicum virgatum, Kentucky-31, and Bromus ciliatus, were investigated after 230d of growth and multiple runoff treatment events. After 183d of periodic runoff application, the concentrations of Zn, Cu, Pb and Cd with low and high loadings had the same trends in the plant tissues, Zn>Cu>Pb>Cd, following the trend of the input metal concentrations. The fates of input metals were 88-97% captured in soil media, 2.0-11.6% not captured by bioretention media, and 0.5-3.3% accumulated in plants. Compared to the metals retained by the soil, the percentages of input metals taken up by plants were relatively low due to the low plant biomass produced in this study. Greater biomass density would be required for the vegetation to have a valuable impact in prolonging the lifetime of a bioretention cell.

  14. Heavy metal removal from sediments by biosurfactants.

    PubMed

    Mulligan, C N; Yong, R N; Gibbs, B F

    2001-07-30

    Batch washing experiments were used to evaluate the feasibility of using biosurfactants for the removal of heavy metals from sediments. Surfactin from Bacillus subtilis, rhamnolipids from Pseudomonas aeruginosa and sophorolipid from Torulopsis bombicola were evaluated using a metal-contaminated sediment (110mg/kg copper and 3300mg/kg zinc). A single washing with 0.5% rhamnolipid removed 65% of the copper and 18% of the zinc, whereas 4% sophorolipid removed 25% of the copper and 60% of the zinc. Surfactin was less effective, removing 15% of the copper and 6% of the zinc. The technique of ultrafiltration and zeta potential measurements were used to determine the mechanism of metal removal by the surfactants. It was then postulated that metal removal by the biosurfactants occurs through sorption of the surfactant on to the soil surface and complexation with the metal, detachment of the metal from the soil into the soil solution and hence association with surfactant micelles. Sequential extraction procedures were used on the sediment to determine the speciation of the heavy metals before and after surfactant washing. The carbonate and oxide fractions accounted for over 90% of the zinc present in the sediments. The organic fraction constituted over 70% of the copper. Sequential extraction of the sediments after washing with the various surfactants indicated that the biosurfactants, rhamnolipid and surfactin could remove the organically-bound copper and that the sophorolipid could remove the carbonate and oxide-bound zinc. Therefore, heavy metal removal from sediments is feasible and further research will be conducted.

  15. Arbuscular Mycorrhizal Fungi Can Benefit Heavy Metal Tolerance and Phytoremediation

    ERIC Educational Resources Information Center

    Forgy, David

    2012-01-01

    Sites contaminated by heavy metals, such as industrial waste sites, create unwelcoming environments for plant growth. Heavy metals can have a wide range of toxic effects such as replacing essential elements or disrupting enzyme function. While some heavy metals are essential to plant nutrition at low concentrations, high concentrations of any…

  16. Bacterial sorption of heavy metals

    SciTech Connect

    Mullen, M.D.; Wolf, D.C.; Ferris, F.G.; Beveridge, T.J.; Flemming, C.A.

    1989-01-01

    Four bacteria, Bacillus cereus, B. subtilis, Escherichia coli, and Pseudomonas aeruginosa, were examined for the ability to remove Ag{sup +}, Cd{sup 2+}, Cu{sup 2+}, and La{sup 3+} from solution by batch equilibration methods. Cd and Cu sorption over the concentration range 0.001 to 1 mM was described by Freundlich isotherms. At 1 mM concentrations of both Cd{sup 2+} and Cu{sup 2+}, P. aeruginosa and B. cereus were the most and least efficient at metal removal, respectively. Freundlich K constants indicated that E. coli was most efficient at Cd{sup 2+} removal and B. subtilis removed the most Cu{sup 2+}. Removal of Ag{sup +} from solution by bacteria was very efficient; an average of 89% of the total Ag{sup +} was removed from the 1 mM solution, whereas only 12, 29, and 27% of the total Cd{sup 2+}, Cu{sup 2+}, and La{sup 3+}, respectively, were sorbed from 1 mM solutions. Electron microscopy indicated that La{sup 3+} accumulated at the cell surface as needlelike, crystalline precipitates. Silver precipitated as discrete colloidal aggregates at the cell surface and occasionally in the cytoplasma. The results indicate that bacterial cells are capable of binding large quantities of different metals.

  17. Customizable Biopolymers for Heavy Metal Remediation

    NASA Astrophysics Data System (ADS)

    Kostal, Jan; Prabhukumar, Giridhar; Lao, U. Loi; Chen, Alin; Matsumoto, Mark; Mulchandani, Ashok; Chen*, Wilfred

    2005-10-01

    Nanoscale materials have been gaining increasing interest in the area of environmental remediation because of their unique physical, chemical and biological properties. One emerging area of research has been the development of novel materials with increased affinity, capacity, and selectivity for heavy metals because conventional technologies are often inadequate to reduce concentrations in wastewater to acceptable regulatory standards. Genetic and protein engineering have emerged as the latest tools for the construction of nanoscale materials that can be controlled precisely at the molecular level. With the advent of recombinant DNA techniques, it is now possible to create `artificial' protein polymers with fundamentally new molecular organization. The most significant feature of these nanoscale biopolymers is that they are specifically pre-programmed within a synthetic gene template and can be controlled precisely in terms of sizes, compositions and functions at the molecular level. In this review, the use of specifically designed protein-based nano-biomaterials with both metal-binding and tunable properties for heavy metal removal is summarized. Several different strategies for the selective removal of heavy metals such as cadmium and mercury are highlighted.

  18. Remediation processes for heavy metals contaminated soils

    SciTech Connect

    Torma, G.A.; Torma, A.E.; Hsu, Pei-Cheng

    1996-12-31

    This paper provides information on selected technologies available for remediation of metal contaminated soils and industrial effluent solutions. Because some of the industrial sites are contaminated with organics (solvents, gasolines and oils), an effort has been made to introduce the most frequently used cost-effective cleanup methods, such as {open_quotes}bioventing{close_quotes} and {open_quotes}composting.{close_quotes} The microorganisms involved in these processes are capable of degrading organic soil contaminants to environmentally harmless compounds: water and carbon dioxide. Heavy metals and radionuclides contaminated mining and industrial sites can be remediated by using adapted heap and dump leaching technologies, which can be chemical in nature or bio-assisted. The importance of volume reduction by physical separation is discussed. A special attention is devoted to the remediation of soils by leaching (soil washing) to remove heavy metal contaminants, such as chromium, lead, nickel and cadmium. Furthermore, the applicability of biosorption technology in the remediation of heavy metals and radionuclides contaminated industrial waste waters and acidic mining effluent solutions was indicated. 60 refs., 9 figs.

  19. Heavy metals and the origin of life

    NASA Astrophysics Data System (ADS)

    Nriagu, J.

    2003-05-01

    The functional value of heavy metals in proto-cells was immense and involved critical roles in catalysis of molecular synthesis, translation, electrical neutrality and conduction, energy capture, cross-linking and precipitation (stabilizers of protective cell walls), and to a limited extent, osmotic pressure control. Metals must have modulated the evolutionary choices of the types of building blocks, such as ribose sugars as a constituent of RNA, or the the chirality and enantiopurity of many biomolecules. The formation of an enclosing membrane led to intracellular prokaryotic life (believed to have originated in an anaerobic environment) and much enhanced control over primary metabolism, the uptake and incorporation of heavy metals and the management of biomolecules (especially RNA, DNA and proteins) that were formed. Cells of the most primitive organisms (archaebacteria) reveal complex mechanisms designed specifically to deal with selective pressures from metal-containing environments including intra- and extra-cellular sequestration, exclusion by cell wall barrier, removal through active efflux pumps, enzymatic detoxification, and reduction in sensitivity of cellular targets to metal ions. Adaptation to metals using a variety of chromosomal, and transposon and plasmid-mediated systems began early in the evolution of life on Earth. Recent studies, however, show that the roles played by many heavy metals have changed over time. Divalent lead, for instance, has relinquished its unique catalytic role in the conversion of carbohydrates into ribose in the prebiotic world. The putative elements that dominated the primordial biochemistry were V, Mo, W, Co, Fe(II) and Ni; with the development of oxygenated atmosphere, these elements gave way to Zn, Cu and Fe(Ill) in their metabolic functions.

  20. The different poisoning behaviors of various alkali metal containing compounds on SCR catalyst

    NASA Astrophysics Data System (ADS)

    Du, Xuesen; Yang, Guangpeng; Chen, Yanrong; Ran, Jingyu; Zhang, Li

    2017-01-01

    Alkali metals are poisonous to the metal oxide catalyst for NO removal. The chemical configuration of alkali containing substance and interacting temperature can affect the poisoning profile. A computational method based on Frontier Molecular Orbital analysis was proposed to determine the reacting behavior of various alkali-containing substances with SCR catalyst. The results reveal that the poisoning reactivities of various substances can be ranked as: E (MOH) > E (M2SO4) > E(MCl) > E(MNO3) > E(MHSO4). The experimental activity tests of the catalysts calcined at stepped temperatures show that NaOH can react with the catalyst below 200 °C. NaCl and NaNO3 start to react with the catalyst at a temperature between 300 and 400 °C. Unlike MOH, MCl and MNO3, which can produce volatile or decomposable species for the anions after reacting with the catalyst, M2SO4 and MHSO4 will leave both cations and anions on the catalyst surface. The sulfate ions left on the catalyst can generate active acid sites for NH3 adsorption. The experimental results also show that Na2SO4 and NaHSO4 will not lower the NO conversion. The after-reaction influences of various alkali metals were studied using theoretical and experimental methods. The theoretical results show that the acidity decreases with doping of alkali metal. Experiments show a consistent result that the NO conversion decreases as undoped >LiCl > NaCl > KCl.

  1. Stabilize heavy metals in soils and sludges

    SciTech Connect

    1995-03-01

    To stabilize heavy metals in soils, sludges, ash from incinerators and power plants, and baghouse dusts, Solucorp Industries (Saddle Brook, N.J.) has developed the Molecular Bonding System (MBS). Using a patented mix of chemical additives, the MBS process bonds highly reactive metal ions to form non-leachable molecules, rendering the metals inert. The chemical reactions are said to be permanent, and for each application, the additive mix is specially formulated to meet site-specific conditions. Recently, the MBS process was accepted into the US Environmental Protection Agency`s Site Demonstration Program as an innovative technology for stabilizing heavy metals. Bench-scale and pilot tests have proven the effectiveness of the MBS process for a wide array of metals, including arsenic, cadmium, chromium, copper, lead, mercury, nickel, silver and zinc. The process is designed for wastes classified as D004 through D011, as well as K-listed wastes associated with metal-plating operations. It can treat waste in drums or in bulk, says the firm, but is not suitable for liquid streams.

  2. Determination of heavy metals in the ambient atmosphere.

    PubMed

    Suvarapu, Lakshmi Narayana; Baek, Sung-Ok

    2017-01-01

    Heavy metal determination in ambient air is an important task for environmental researchers because of their toxicity to human beings. Some heavy metals (hexavalent chromium (Cr), arsenic (As), cadmium (Cd) and nickel (Ni)) have been listed as carcinogens. Furthermore, heavy metals in the atmosphere can accumulate in various plants and animals and enter humans through the food chain. This article reviews the determination of heavy metals in the atmosphere in different areas of the world since 2006. The results showed that most researchers concentrated on toxic metals, such as Cr, Cd, Ni, As and lead. A few studies used plant materials as bio-monitors for the atmospheric levels of heavy metals. Some researchers found higher concentrations of heavy metals surrounding industrial areas compared with residential and/or commercial areas. Most studies reported the major sources of the particulate matter and heavy metals in the atmosphere to be industrial emissions, vehicular emissions and secondary aerosols.

  3. Effects of inherent alkali and alkaline earth metallic species on biomass pyrolysis at different temperatures.

    PubMed

    Hu, Song; Jiang, Long; Wang, Yi; Su, Sheng; Sun, Lushi; Xu, Boyang; He, Limo; Xiang, Jun

    2015-09-01

    This work aimed to investigate effects of inherent alkali and alkaline earth metallic species (AAEMs) on biomass pyrolysis at different temperatures. The yield of CO, H2 and C2H4 was increased and that of CO2 was suppressed with increasing temperature. Increasing temperature could also promote depolymerization and aromatization reactions of active tars, forming heavier polycyclic aromatic hydrocarbons, leading to decrease of tar yields and species diversity. Diverse performance of inherent AAEMs at different temperatures significantly affected the distribution of pyrolysis products. The presence of inherent AAEMs promoted water-gas shift reaction, and enhanced the yield of H2 and CO2. Additionally, inherent AAEMs not only promoted breakage and decarboxylation/decarbonylation reaction of thermally labile hetero atoms of the tar but also enhanced thermal decomposing of heavier aromatics. Inherent AAEMs could also significantly enhance the decomposition of levoglucosan, and alkaline earth metals showed greater effect than alkali metals.

  4. Effect of heavy metals on bacterial transport

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Olson, M. S.

    2010-12-01

    Adsorption of metals onto bacteria and soil takes place as stormwater runoff infiltrates into the subsurface. Changes in both bacterial surfaces and soil elemental content have been observed, and may alter the attachment of bacteria to soil surfaces. In this study, scanning electron microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS) analyses were performed on soil samples equilibrated with synthetic stormwater amended with copper, lead and zinc. The results demonstrate the presence of copper and zinc on soil surfaces. To investigate bacterial attachment behavior, sets of batch sorption experiments were conducted on Escherichia Coli (E. coli) under different chemical conditions by varying solution compositions (nutrient solution vs synthetic stormwater). The adsorption data is best described using theoretical linear isotherms. The equilibrium coefficient (Kd) of E. coli is higher in synthetic stormwater than in nutrient solution without heavy metals. The adsorption of heavy metals onto bacterial surfaces significantly decreases their negative surface charge as determined via zeta potential measurements (-17.0±5.96mv for E. coli equilibrated with synthetic stormwater vs -21.6±5.45mv for E. coli equilibrated with nutrient solution), indicating that bacterial attachment may increase due to the attachment of metals onto bacterial surfaces and their subsequent change in surface charge. The attachment efficiency (α) of bacteria was also calculated and compared for both solution chemistries. Bacterial attachment efficiency (α) in synthetic stormwater is 0.997, which is twice as high as that in nutrient solution(α 0.465). The ratio of bacterial diameter : collector diameter suggests minimal soil straining during bacterial transport. Results suggest that the presence of metals in synthetic stormwater leads to an increase in bacterial attachment to soil surfaces. In terms of designing stormwater infiltration basins, the presence of heavy metals seems to

  5. Environmental impact of mercury and other heavy metals

    NASA Astrophysics Data System (ADS)

    Lindqvist, Oliver

    The environmental impact of heavy metals is reviewed. One significant source of emissions of heavy metals to air is waste incineration. Consumer batteries contributes significantly to this problem, as well as to heavy metal leakage to groundwater from landfill deposits. The situation in Sweden is used as an example to describe how the deposition from the atmosphere still is increasing the load of heavy metals, like mercury, cadmium and lead, in top soils and aquatic sediments. Critical factors and effect levels for Hg, Cd, Pb, Cu, Zn and As are discussed. Specific questions like mercury contents in present battery waste and heavy metal contents in new and future secondary batteries are addressed.

  6. Heavy metal pollution in aquatic ecosystems and its phytoremediation using wetland plants: An ecosustainable approach

    SciTech Connect

    Rai, P.K.

    2008-07-01

    This review addresses the global problem of heavy metal pollution originating from increased industrialization and urbanization and its amelioration by using wetland plants both in a microcosm as well as natural/field condition. This review mentions salient features of wetland ecosystems, their vegetation component, and the pros and cons involved in heavy metal removal. Wetland plants are preferred over other bio-agents due to their low cost, frequent abundance in aquatic ecosystems, and easy handling. Constructed wetlands proved to be effective for the abatement of heavy metal pollution from acid mine drainage; landfill leachate; thermal power; and municipal, agricultural, refinery, and chlor-alkali effluent. the physicochemical properties of wetlands provide many positive attributes for remediating heavy metals. Typha, Phragmites, Eichhornia, Azolla, Lemna, and other aquatic macrophytes are some of the potent wetland plants for heavy metal removal. Biomass disposal problem and seasonal growth of aquatic macrophytes are some limitations in the transfer of phytoremediation technology from the laboratory to the field. However, the disposed biomass of macrophytes may be used for various fruitful applications. An ecosustainable model has been developed through the author's various works, which may ameliorate some of the limitations. The creation of more areas for phytoremediation may also aid in wetlands conservation. Genetic engineering and biodiversity prospecting of endangered wetland plants are important future prospects in this regard.

  7. Multiple heavy metal removal using an entomopathogenic fungi Beauveria bassiana.

    PubMed

    Gola, Deepak; Dey, Priyadarshini; Bhattacharya, Arghya; Mishra, Abhishek; Malik, Anushree; Namburath, Maneesh; Ahammad, Shaikh Ziauddin

    2016-10-01

    Towards the development of a potential remediation technology for multiple heavy metals [Zn(II), Cu(II), Cd(II), Cr(VI) and Ni(II)] from contaminated water, present study examined the growth kinetics and heavy metal removal ability of Beauveria bassiana in individual and multi metals. The specific growth rate of B. bassiana varied from 0.025h(-1) to 0.039h(-1) in presence of individual/multi heavy metals. FTIR analysis indicated the involvement of different surface functional groups in biosorption of different metals, while cellular changes in fungus was reflected by various microscopic (SEM, AFM and TEM) analysis. TEM studies proved removal of heavy metals via sorption and accumulation processes, whereas AFM studies revealed increase in cell surface roughness in fungal cells exposed to heavy metals. Present study delivers first report on the mechanism of bioremediation of heavy metals when present individually as well as multi metal mixture by entomopathogenic fungi.

  8. Earthworm contamination by PCBs and heavy metals

    SciTech Connect

    Diercxsens, P.; de Weck, D.; Borsinger, N.; Rosset, B.; Tarradellas, J.

    1985-01-01

    A comparison is made of soil and earthworm contamination by PCBs and heavy metals between a nature reserve and two sites conditioned by the addition of sewage sludge and compost. The tissues and gut content of the earthworms shows a higher PCB concentration than that of the surrounding soil and also a difference in the fingerprint of some single PCB compounds. Earthworms display a selective accumulation of cadmium and zinc in their tissues and gut content.

  9. Modeling heavy metal removal in wetlands

    SciTech Connect

    Lung, W.S.; Light, R.N.

    1994-12-31

    Although the use of wetland ecosystems to purify water has gained increased attention only recently, it has been recognized as a wastewater treatment technique for centuries. While considerable research has occurred to quantify the nutrient (nitrogen and phosphorus) removal mechanisms of wetlands, relatively few investigators have focused on the mechanisms of heavy metal removal and uptake by wetland sediments and plants. The quantification of the assimilative capacity of heavy metals by wetland ecosystems is a critical component in the design and use of wetlands for this purpose. A computer model has been developed to simulate the fate and transport of heavy metals introduced to a wetland ecosystem. Modeled water quality variables include phytoplankton biomass and productivity; macrophyte (Nulumbo lutea) biomass; total phosphorus in the water column; dissolved copper in the water column and sediments; particulate copper in the water column and sediments; and suspended solids. These variables directly affect the calculated rate of copper uptake by macrophytes, and the rate of copper recycling as a function of the decomposition of copper-laden biomass litter. The model was calibrated using total phosphorus and chlorophyll a data from the Old Woman Creek Wetland in Ohio. Verification of the model was achieved using data on the copper content of the macrophyte Nelumbo lutea.

  10. [Research advances in heavy metals pollution ecology of diatom].

    PubMed

    Ding, Teng-Da; Ni, Wan-Min; Zhang, Jian-Ying

    2012-03-01

    Diatom, due to its high sensitivity to environmental change, is one of the bio-indicators of aquatic ecosystem health, and some typical diatom species have been applied to indicate the heavy metals pollution of water body. With the focus on the surface water heavy metals pollution, this paper reviewed the research advances in the toxic effect of heavy metals pollution on diatom, biosorption and bioaccumulation of heavy metals by diatom, ecological adaptation mechanisms of diatom to heavy metals pollution, and roles of diatom as bio-indicator and in ecological restoration of heavy metals pollution. The growth tendency of diatom and the morphological change of frustule under heavy metals pollution as well as the differences in heavy metals biosorption and bioaccumulation by diatom, the ecological adaptation mechanisms of diatom on heavy metals surface complexation and ion exchange, and the roles of diatom as bio-indicator and in ecological restoration of heavy metals polluted water body were also discussed. This review could provide scientific evidences for the prevention of aquatic ecosystems heavy metals pollution and related early warning techniques.

  11. Plant rhamnogalacturonan II complexation of heavy metal cations

    DOEpatents

    O`Neill, M.A.; Pellerin, P.J.M.; Warrenfeltz, D.; Vidal, S.; Darvill, A.G.; Albersheim, P.

    1999-03-02

    The present invention provides rhamnogalacturonan-II (RG-II) and relates to its ability to complex specific multivalent heavy metal cations. In the presence of boric acid, RG-II monomers form dimers that are cross-linked by a borate ester. The yield of such borate ester cross-linked dimers of RG-II is enhanced in the presence of specific heavy metal cations. The present invention further relates to the utility of RG-II in assays for the detection of specific heavy metal contamination; as a reagent useful in the removal of specific heavy metal cations contaminating foods and liquids, for example, fish, wines, etc.; as a pharmaceutical composition useful as an antidote in specific heavy metal cation poisoning; as a treatment for the detoxification of specific heavy metal cations from blood and/or tissues; and in a method of remediation of waters and soils contaminated with specific heavy metal cations. 15 figs.

  12. Plant rhamnogalacturonan II complexation of heavy metal cations

    DOEpatents

    O'Neill, Malcolm A.; Pellerin, Patrice J. M.; Warrenfeltz, Dennis; Vidal, Stephane; Darvill, Alan G.; Albersheim, Peter

    1999-01-01

    The present invention provides rhamnogalacturonan-II (RG-II) and relates to its ability to complex specific multivalent heavy metal cations. In the presence of boric acid, RG-II monomers form dimers that are cross-linked by a borate ester. The yield of such borate ester cross-linked dimers of RG-II is enhanced in the presence of specific heavy metal cations. The present invention further relates to the utility of RG-II in assays for the detection of specific heavy metal contamination; as a reagent useful in the removal of specific heavy metal cations contaminating foods and liquids, for example, fish, wines, etc.; as a pharmaceutical composition useful as an antidote in specific heavy metal cation poisoning; as a treatment for the detoxification of specific heavy metal cations from blood and/or tissues; and in a method of remediation of waters and soils contaminated with specific heavy metal cations.

  13. Hyperfine frequency shift and Zeeman relaxation in alkali-metal-vapor cells with antirelaxation alkene coating

    NASA Astrophysics Data System (ADS)

    Corsini, Eric P.; Karaulanov, Todor; Balabas, Mikhail; Budker, Dmitry

    2013-02-01

    An alkene-based antirelaxation coating for alkali-metal vapor cells exhibiting Zeeman relaxation times up to 77 s was recently identified by Balabas The long relaxation times, two orders of magnitude longer than in paraffin- (alkane-) coated cells, motivate revisiting the question of what the mechanism is underlying wall-collision-induced relaxation and renew interest in applications of alkali-metal vapor cells to secondary frequency standards. We measure the width and frequency shift of the ground-state hyperfine mF=0→mF'=0 transition (clock resonance) in vapor cells with 85Rb and 87Rb atoms, with an alkene antirelaxation coating. We find that the frequency shift is slightly larger than for paraffin-coated cells and that the Zeeman linewidth scales linearly with the hyperfine frequency shift.

  14. Calculation of radiative corrections to hyperfine splittings in the neutral alkali metals

    SciTech Connect

    Sapirstein, J.; Cheng, K.T.

    2003-02-01

    The radiative correction to hyperfine splitting in hydrogen is dominated by the Schwinger term, {alpha}/2{pi} E{sub F}, where E{sub F} is the lowest-order hyperfine splitting. Binding corrections to this term, which enter as powers and logarithms of Z{alpha}, can be expected to be increasingly important in atoms with higher nuclear charge Z. Methods that include all orders of Z{alpha}, developed first to study highly charged ions, are adapted to the study of the neutral alkali metals, lithium through francium. It is shown that the use of the Schwinger term alone to account for radiative corrections to hyperfine splittings becomes qualitatively incorrect for the heavier alkali metals.0.

  15. Electronic states of alkali metal-NTCDA complexes: A DFT study

    NASA Astrophysics Data System (ADS)

    Tachikawa, Hiroto; Kawabata, Hiroshi

    2015-10-01

    Structures and electronic states of organic-inorganic compound of 1,4,5,8-naphthalene-tetracarboxylic-dianhydride (NTCDA) with alkali metals, Mn(NTCDA) (Mdbnd Li and Na, n = 0-2), have been investigated by means of hybrid density functional theory (DFT) calculations. From the DFT calculations, it was found that the electronic state of the complex at the ground state is characterized by a charge-transfer state expressed by (M)+(NTCDA)-. The alkali metals were bound equivalently to the carbonyl oxygen and ether oxygen atoms of NTCDA. The Cdbnd O double bond character of NTCDA was changed to a C-O single bond like character by the strong interaction of M to the Cdbnd O and O sites. This change was the origin of the red-shift of the IR spectrum. The UV-vis absorption spectra of Mn(NTCDA) were theoretically predicted on the basis of theoretical results.

  16. X-ray Compton scattering experiments for fluid alkali metals at high temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Matsuda, K.; Fukumaru, T.; Kimura, K.; Tamura, K.; Katoh, M.; Kajihara, Y.; Inui, M.; Yao, M.; Itou, M.; Sakurai, Y.

    2015-08-01

    We have developed a high-pressure vessel and a cell for x-ray Compton scattering measurements of fluid alkali metals. Measurements have been successfully carried out for alkali metal rubidium at elevated temperatures and pressures using synchrotron radiation at SPring-8. The width of Compton profiles (CPs) of fluid rubidium becomes narrow with decreasing fluid density, which indicates that the CPs sensitively detect the effect of reduction in the valence electron density. At the request of all authors of the paper, and with the agreement of the Proceedings Editor, an updated version of this article was published on 10 September 2015. The original article supplied to AIP Publishing was not the final version and contained PDF conversion errors in Formulas (1) and (2). The errors have been corrected in the updated and re-published article.

  17. X-ray Compton scattering experiments for fluid alkali metals at high temperatures and pressures

    SciTech Connect

    Matsuda, K. Fukumaru, T.; Kimura, K.; Yao, M.; Tamura, K.; Katoh, M.; Kajihara, Y.; Inui, M.; Itou, M.; Sakurai, Y.

    2015-08-17

    We have developed a high-pressure vessel and a cell for x-ray Compton scattering measurements of fluid alkali metals. Measurements have been successfully carried out for alkali metal rubidium at elevated temperatures and pressures using synchrotron radiation at SPring-8. The width of Compton profiles (CPs) of fluid rubidium becomes narrow with decreasing fluid density, which indicates that the CPs sensitively detect the effect of reduction in the valence electron density. At the request of all authors of the paper, and with the agreement of the Proceedings Editor, an updated version of this article was published on 10 September 2015. The original article supplied to AIP Publishing was not the final version and contained PDF conversion errors in Formulas (1) and (2). The errors have been corrected in the updated and re-published article.

  18. Interaction of alkali metal cations and short chain alcohols: effect of core size on theoretical affinities

    NASA Astrophysics Data System (ADS)

    Ma, N. L.; Siu, F. M.; Tsang, C. W.

    2000-05-01

    The effect of core size on the calculated binding energies of alkali metal cations (Li +, Na +, K +) to methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, and t-butanol are evaluated using G2(MP2,SVP) protocol. The K + affinities, reported for the first time, were found to be negative if a core size larger than that of neon (2s 22p 6) was used. Given this, we suggest that the 1s 2, 2s 22p 6, and 3s 23p 6 electrons have to be included in the electron correlation treatment for Li +, Na + and K + containing species, respectively. With these core sizes, our G2(MP2,SVP) Li + and Na + affinities are in excellent agreement with values obtained from the newly developed G3 protocol. The nature of alkali metal cation-alcohol interaction is also discussed.

  19. Reactions between cold methyl halide molecules and alkali-metal atoms

    SciTech Connect

    Lutz, Jesse J.; Hutson, Jeremy M.

    2014-01-07

    We investigate the potential energy surfaces and activation energies for reactions between methyl halide molecules CH{sub 3}X (X = F, Cl, Br, I) and alkali-metal atoms A (A = Li, Na, K, Rb) using high-level ab initio calculations. We examine the anisotropy of each intermolecular potential energy surface (PES) and the mechanism and energetics of the only available exothermic reaction pathway, CH{sub 3}X + A → CH{sub 3} + AX. The region of the transition state is explored using two-dimensional PES cuts and estimates of the activation energies are inferred. Nearly all combinations of methyl halide and alkali-metal atom have positive barrier heights, indicating that reactions at low temperatures will be slow.

  20. An Aqueous Redox Flow Battery Based on Neutral Alkali Metal Ferri/ferrocyanide and Polysulfide Electrolytes

    SciTech Connect

    Wei, Xiaoliang; Xia, Gordon; Kirby, Brent W.; Thomsen, Edwin C.; Li, Bin; Nie, Zimin; Graff, Gordon L.; Liu, Jun; Sprenkle, Vincent L.; Wang, Wei

    2015-11-13

    Aiming to explore low-cost redox flow battery systems, a novel iron-polysulfide (Fe/S) flow battery has been demonstrated in a laboratory cell. This system employs alkali metal ferri/ferrocyanide and alkali metal polysulfides as the redox electrolytes. When proper electrodes, such as pretreated graphite felts, are used, 78% energy efficiency and 99% columbic efficiency are achieved. The remarkable advantages of this system over current state-of-the-art redox flow batteries include: 1) less corrosive and relatively environmentally benign redox solutions used; 2) excellent energy and utilization efficiencies; 3) low cost for redox electrolytes and cell components. These attributes can lead to significantly reduced capital cost and make the Fe/S flow battery system a promising low-cost energy storage technology. The major drawbacks of the present cell design are relatively low power density and possible sulfur species crossover. Further work is underway to address these concerns.

  1. Cavitation luminescence of argon-saturated alkali-metal solutions from a conical bubble

    NASA Astrophysics Data System (ADS)

    Jing, Ha; Jie He, Shou; Fang, Wang; Min, Song Jian

    2008-10-01

    In 1,2-propanediol solutions containing sodium chloride, spectra of luminescence from a collapsed conical bubble have been detected. Results show that the spectra consist of a broad continuum background, on which a resonance line arising from de-excitation of sodium atom at 589 nm and two satellite diffuse bands at ~554 nm and 620 nm respectively are superimposed. These are confirmed to be the emission from alkali-metal-argon exciplexes and are suggested to occur when the mixtures of alkali metal vapour and argon are rapidly compressed. The intracavity density of argon deduced from the line shift of Na resonance line data is estimated to be about 2 × 1026 m-3.

  2. Three-body recombination in cold helium-helium-alkali-metal-atom collisions

    SciTech Connect

    Suno, Hiroya; Esry, B. D.

    2009-12-15

    Three-body recombination in helium-helium-alkali-metal collisions at cold temperatures is studied using the adiabatic hyperspherical representation. The rates for the three-body recombination processes {sup 4}He+{sup 4}He+X->{sup 4}He+{sup 4}HeX and {sup 4}He+{sup 4}He+X->{sup 4}He{sub 2}+X, with X={sup 7}Li, {sup 23}Na, {sup 39}K, {sup 85}Rb, and {sup 133}Cs, are calculated at nonzero collision energies by including not only zero total angular momentum, J=0, states but also J>0 states. The three-body recombination rates show a relatively weak dependence on the alkali-metal species, differing from each other only by about one order of magnitude, except for the {sup 4}He-{sup 4}He-{sup 23}Na system.

  3. Material Removes Heavy Metal Ions From Water

    NASA Technical Reports Server (NTRS)

    Philipp, Warren H., Jr.; Street, Kenneth W.; Hill, Carol; Savino, Joseph M.

    1995-01-01

    New high capacity ion-exchange polymer material removes toxic metal cations from contaminated water. Offers several advantages. High sensitivities for such heavy metals as lead, cadmium, and copper and capable of reducing concentrations in aqueous solutions to parts-per-billion range. Removes cations even when calcium present. Material made into variety of forms, such as thin films, coatings, pellets, and fibers. As result, adapted to many applications to purify contaminated water, usually hard wherever found, whether in wastewater-treatment systems, lakes, ponds, industrial plants, or homes. Another important feature that adsorbed metals easily reclaimed by either destructive or nondestructive process. Other tests show ion-exchange polymer made inexpensively; easy to use; strong, flexible, not easily torn; and chemically stable in storage, in aqueous solutions, and in acidic or basic solution.

  4. Development of processes for the production of solar grade silicon from halides and alkali metals

    NASA Technical Reports Server (NTRS)

    Dickson, C. R.; Gould, R. K.

    1980-01-01

    High temperature reactions of silicon halides with alkali metals for the production of solar grade silicon in volume at low cost were studied. Experiments were performed to evaluate product separation and collection processes, measure heat release parameters for scaling purposes, determine the effects of reactants and/or products on materials of reactor construction, and make preliminary engineering and economic analyses of a scaled-up process.

  5. High field superconductivity in alkali metal intercalates of MoS2

    NASA Technical Reports Server (NTRS)

    Woollam, J. A.; Flood, D. J.; Wagoner, D. E.; Somoano, R. B.; Rembaum, A.

    1973-01-01

    In the search for better high temperature, high critical field superconductors, a class of materials was found which have layered structures and can be intercalated with various elements and compounds. Since a large number of compounds can be formed, intercalation provides a method of control of superconducting properties. They also provide the possible medium for excitonic superconductivity. Results of magnetic field studies are presented on alkali metal (Na, K, Rb, and Cs) intercalated MoS2 (2H polymorph).

  6. An embedded-atom-method model for alkali-metal vibrations.

    PubMed

    Wilson, R B; Riffe, D M

    2012-08-22

    We present an embedded-atom-method (EAM) model that accurately describes the vibrational dynamics in the alkali metals Li, Na, K, Rb and Cs. The bulk dispersion curves, frequency-moment Debye temperatures and temperature-dependent entropy Debye temperatures are all in excellent agreement with experimental results. The model is also well suited for studying surface vibrational dynamics in these materials, as illustrated by calculations for the Na(110) surface.

  7. Removal of toxic and alkali/alkaline earth metals during co-thermal treatment of two types of MSWI fly ashes in China.

    PubMed

    Yu, Jie; Qiao, Yu; Jin, Limei; Ma, Chuan; Paterson, Nigel; Sun, Lushi

    2015-12-01

    This study aims to vaporize heavy metals and alkali/alkaline earth metals from two different types of fly ashes by thermal treatment method. Fly ash from a fluidized bed incinerator (HK fly ash) was mixed with one from a grate incinerator (HS fly ash) in various proportions and thermally treated under different temperatures. The melting of HS fly ash was avoided when treated with HK fly ash. Alkali/alkaline earth metals in HS fly ash served as Cl-donors to promote the vaporization of heavy metals during thermal treatment. With temperature increasing from 800 to 900°C, significant amounts of Cl, Na and K were vaporized. Up to 1000°C in air, less than 3% of Cl and Na and less than 5% of K were retained in ash. Under all conditions, Cd can be vaporized effectively. The vaporization of Pb was mildly improved when treated with HS fly ash, while the effect became less pronounced above 900°C. Alkali/alkaline earth metals can promote Cu vaporization by forming copper chlorides. Comparatively, Zn vaporization was low and only slightly improved by HS fly ash. The low vaporization of Zn could be caused by the formation of Zn2SiO4, ZnFe2O4 and ZnAl2O4. Under all conditions, less than 20% of Cr was vaporized. In a reductive atmosphere, the vaporization of Cd and Pb were as high as that in oxidative atmosphere. However, the vaporization of Zn was accelerated and that of Cu was hindered because the formation of Zn2SiO4, ZnFe2O4 and ZnAl2O4 and copper chloride was depressed in reductive atmosphere.

  8. Magnetoresistance in paramagnetic heavy fermion metals.

    PubMed

    Parihari, D; Vidhyadhiraja, N S

    2009-10-07

    A theoretical study of magnetic field (h) effects on single-particle spectra and the transport quantities of heavy fermion metals in the paramagnetic phase is carried out. We have employed a non-perturbative local moment approach (LMA) to the asymmetric periodic Anderson model within the dynamical mean field framework. The lattice coherence scale ω(L), which is proportional within the LMA to the spin-flip energy scale, and has been shown in earlier studies to be the energy scale at which crossover to single-impurity physics occurs, increases monotonically with increasing magnetic field. The many body Kondo resonance in the density of states at the Fermi level splits into two, with the splitting being proportional to the field itself. For h≥0, we demonstrate adiabatic continuity from the strongly interacting case to a corresponding non-interacting limit, thus establishing Fermi liquid behaviour for heavy fermion metals in the presence of a magnetic field. In the Kondo lattice regime, the theoretically computed magnetoresistance is found to be negative in the entire temperature range. We argue that such a result could be understood at [Formula: see text] by field-induced suppression of spin-flip scattering and at [Formula: see text] through lattice coherence. The coherence peak in the heavy fermion resistivity diminishes and moves to higher temperatures with increasing field. Direct comparison of the theoretical results to the field dependent resistivity measurements in CeB(6) yields good agreement.

  9. Advances in Understanding How Heavy Metal Pollution Triggers Gastric Cancer.

    PubMed

    Yuan, Wenzhen; Yang, Ning; Li, Xiangkai

    2016-01-01

    With the development of industrialization and urbanization, heavy metals contamination has become a major environmental problem. Numerous investigations have revealed an association between heavy metal exposure and the incidence and mortality of gastric cancer. The mechanisms of heavy metals (lead, cadmium, mercury, chromium, and arsenic) contamination leading to gastric cancer are concluded in this review. There are four main potential mechanisms: (1) Heavy metals disrupt the gastric mucosal barrier by decreasing mucosal thickness, mucus content, and basal acid output, thereby affecting the function of E-cadherin and inducing reactive oxygen species (ROS) damage. (2) Heavy metals directly or indirectly induce ROS generation and cause gastric mucosal and DNA lesions, which subsequently alter gene regulation, signal transduction, and cell growth, ultimately leading to carcinogenesis. Exposure to heavy metals also enhances gastric cancer cell invasion and metastasis. (3) Heavy metals inhibit DNA damage repair or cause inefficient lesion repair. (4) Heavy metals may induce other gene abnormalities. In addition, heavy metals can induce the expression of proinflammatory chemokine interleukin-8 (IL-8) and microRNAs, which promotes tumorigenesis. The present review is an effort to underline the human health problem caused by heavy metal with recent development in order to garner a broader perspective.

  10. Advances in Understanding How Heavy Metal Pollution Triggers Gastric Cancer

    PubMed Central

    Yuan, Wenzhen; Yang, Ning

    2016-01-01

    With the development of industrialization and urbanization, heavy metals contamination has become a major environmental problem. Numerous investigations have revealed an association between heavy metal exposure and the incidence and mortality of gastric cancer. The mechanisms of heavy metals (lead, cadmium, mercury, chromium, and arsenic) contamination leading to gastric cancer are concluded in this review. There are four main potential mechanisms: (1) Heavy metals disrupt the gastric mucosal barrier by decreasing mucosal thickness, mucus content, and basal acid output, thereby affecting the function of E-cadherin and inducing reactive oxygen species (ROS) damage. (2) Heavy metals directly or indirectly induce ROS generation and cause gastric mucosal and DNA lesions, which subsequently alter gene regulation, signal transduction, and cell growth, ultimately leading to carcinogenesis. Exposure to heavy metals also enhances gastric cancer cell invasion and metastasis. (3) Heavy metals inhibit DNA damage repair or cause inefficient lesion repair. (4) Heavy metals may induce other gene abnormalities. In addition, heavy metals can induce the expression of proinflammatory chemokine interleukin-8 (IL-8) and microRNAs, which promotes tumorigenesis. The present review is an effort to underline the human health problem caused by heavy metal with recent development in order to garner a broader perspective. PMID:27803929

  11. Isotopic fractionation of alkali earth metals during carbonate precipitation

    NASA Astrophysics Data System (ADS)

    Yotsuya, T.; Ohno, T.; Muramatsu, Y.; Shimoda, G.; Goto, K. T.

    2014-12-01

    The alkaline earth metals such as magnesium, calcium and strontium play an important role in a variety of geochemical and biological processes. The element ratios (Mg/Ca and Sr/Ca) in marine carbonates have been used as proxies for reconstruction of the past environment. Recently several studies suggested that the study for the isotopic fractionation of the alkaline earth metals in marine carbonates has a potentially significant influence in geochemical research fields (e.g. Eisenhauer et al., 2009). The aim of this study is to explore the influence of carbonate polymorphs (Calcite and Aragonite) and environmental factors (e.g., temperature, precipitation rate) on the level of isotopic fractionation of the alkaline earth metals. We also examined possible correlations between the level of isotopic fractionation of Ca and that of other alkaline earth metals during carbonate precipitation. In order to determine the isotope fractionation factor of Mg, Ca and Sr during carbonate precipitation, calcite and aragonite were synthesized from calcium bicarbonate solution in which the amount of magnesium was controlled based on Kitano method. Calcium carbonates were also prepared from the mixture of calcium chlorite and sodium hydrogen carbonate solutions. The isotope fractionation factors were measured by MC-ICPMS. Results suggested that the level of isotopic fractionation of Mg during carbonate precipitation was correlated with that of Sr and that the change of the carbonate crystal structure could make differences of isotopic fractionations of Mg and Ca, however no difference was found in the case of Sr. In this presentation, the possible mechanism will be discussed.

  12. Metal-to-insulator crossover in alkali doped zeolite

    PubMed Central

    Igarashi, Mutsuo; Jeglič, Peter; Krajnc, Andraž; Žitko, Rok; Nakano, Takehito; Nozue, Yasuo; Arčon, Denis

    2016-01-01

    We report a systematic nuclear magnetic resonance investigation of the 23Na spin-lattice relaxation rate, 1/T1, in sodium loaded low-silica X (LSX) zeolite, Nan/Na12-LSX, for various loading levels of sodium atoms n across the metal-to-insulator crossover. For high loading levels of n ≥ 14.2, 1/T1T shows nearly temperature-independent behaviour between 10 K and 25 K consistent with the Korringa relaxation mechanism and the metallic ground state. As the loading levels decrease below n ≤ 11.6, the extracted density of states (DOS) at the Fermi level sharply decreases, although a residual DOS at Fermi level is still observed even in the samples that lack the metallic Drude-peak in the optical reflectance. The observed crossover is a result of a complex loading-level dependence of electric potential felt by the electrons confined to zeolite cages, where the electronic correlations and disorder both play an important role. PMID:26725368

  13. Metal-to-insulator crossover in alkali doped zeolite

    NASA Astrophysics Data System (ADS)

    Igarashi, Mutsuo; Jeglič, Peter; Krajnc, Andraž; Žitko, Rok; Nakano, Takehito; Nozue, Yasuo; Arčon, Denis

    2016-01-01

    We report a systematic nuclear magnetic resonance investigation of the 23Na spin-lattice relaxation rate, 1/T1, in sodium loaded low-silica X (LSX) zeolite, Nan/Na12-LSX, for various loading levels of sodium atoms n across the metal-to-insulator crossover. For high loading levels of n ≥ 14.2, 1/T1T shows nearly temperature-independent behaviour between 10 K and 25 K consistent with the Korringa relaxation mechanism and the metallic ground state. As the loading levels decrease below n ≤ 11.6, the extracted density of states (DOS) at the Fermi level sharply decreases, although a residual DOS at Fermi level is still observed even in the samples that lack the metallic Drude-peak in the optical reflectance. The observed crossover is a result of a complex loading-level dependence of electric potential felt by the electrons confined to zeolite cages, where the electronic correlations and disorder both play an important role.

  14. Facultative hyperaccumulation of heavy metals and metalloids.

    PubMed

    Pollard, A Joseph; Reeves, Roger D; Baker, Alan J M

    2014-03-01

    Approximately 500 species of plants are known to hyperaccumulate heavy metals and metalloids. The majority are obligate metallophytes, species that are restricted to metalliferous soils. However, a smaller but increasing list of plants are "facultative hyperaccumulators" that hyperaccumulate heavy metals when occurring on metalliferous soils, yet also occur commonly on normal, non-metalliferous soils. This paper reviews the biology of facultative hyperaccumulators and the opportunities they provide for ecological and evolutionary research. The existence of facultative hyperaccumulator populations across a wide edaphic range allows intraspecific comparisons of tolerance and uptake physiology. This approach has been used to study zinc and cadmium hyperaccumulation by Noccaea (Thlaspi) caerulescens and Arabidopsis halleri, and it will be instructive to make similar comparisons on species that are distributed even more abundantly on normal soil. Over 90% of known hyperaccumulators occur on serpentine (ultramafic) soil and accumulate nickel, yet there have paradoxically been few experimental studies of facultative nickel hyperaccumulation. Several hypotheses suggested to explain the evolution of hyperaccumulation seem unlikely when most populations of a species occur on normal soil, where plants cannot hyperaccumulate due to low metal availability. In such species, it may be that hyperaccumulation is an ancestral phylogenetic trait or an anomalous manifestation of physiological mechanisms evolved on normal soils, and may or may not have direct adaptive benefits.

  15. Ion exchange extraction of heavy metals from wastewater sludges.

    PubMed

    Al-Enezi, G; Hamoda, M F; Fawzi, N

    2004-01-01

    Heavy metals are common contaminants of some industrial wastewater. They find their way to municipal wastewaters due to industrial discharges into the sewerage system or through household chemicals. The most common heavy metals found in wastewaters are lead, copper, nickel, cadmium, zinc, mercury, arsenic, and chromium. Such metals are toxic and pose serious threats to the environment and public health. In recent years, the ion exchange process has been increasingly used for the removal of heavy metals or the recovery of precious metals. It is a versatile separation process with the potential for broad applications in the water and wastewater treatment field. This article summarizes the results obtained from a laboratory study on the removal of heavy metals from municipal wastewater sludges obtained from Ardhiya plant in Kuwait. Data on heavy metal content of the wastewater and sludge samples collected from the plant are presented. The results obtained from laboratory experiments using a commercially available ion exchange resin to remove heavy metals from sludge were discussed. A technique was developed to solubilize such heavy metals from the sludge for subsequent treatment by the ion exchange process. The results showed high efficiency of extraction, almost 99.9%, of heavy metals in the concentration range bound in wastewater effluents and sludges. Selective removal of heavy metals from a contaminated wastewater/sludge combines the benefits of being economically prudent and providing the possibility of reuse/recycle of the treated wastewater effluents and sludges.

  16. IRMPD Spectroscopy of Metalated Flavins: Structure and Bonding of Lumiflavin Complexes with Alkali and Coinage Metal Ions.

    PubMed

    Nieto, Pablo; Günther, Alan; Berden, Giel; Oomens, Jos; Dopfer, Otto

    2016-10-01

    Flavins are a fundamental class of biomolecules, whose photochemical properties strongly depend on their environment and their redox and metalation state. Infrared multiphoton dissociation (IRMPD) spectra of mass selected isolated metal-lumiflavin ionic complexes (M+LF) are analyzed in the fingerprint range (800-1830 cm-1) to determine the bonding of lumiflavin with alkali (M=Li, Na, K, Cs) and coinage (M=Cu, Ag) metal ions. The complexes are generated in an electrospray ionization source coupled to an ion cyclotron resonance mass spectrometer and the IR free electron laser FELIX. Vibrational and isomer assignments of the IRMPD spectra are accomplished by comparison to quantum chemical calculations at the B3LYP/cc-pVDZ level, yielding structure, binding energy, bonding mechanism, and spectral properties of the complexes. The most stable binding sites identified in the experiments involve metal bonding to the oxygen atoms of the two available CO groups of LF. Hence, CO stretching frequencies are a sensitive indicator of both the metal binding site and the metal bond strength. More than one isomer is observed for M=Li, Na, and K, and the preferred CO binding site changes with the size of the alkali ion. For Cs+LF only one isomer is identified although the energies of the two most stable structures differ by less than 7 kJ/mol. While the M+-LF bonds for alkali ions are mainly based on electrostatic forces, substantial covalent contributions lead to stronger bonds for the coinage metal ions. Comparison between lumiflavin and lumichrome reveals substantial differences in the metal binding motifs and interactions due to the different flavin structures.

  17. Visualizing plumes of heavy metals and radionuclides

    NASA Astrophysics Data System (ADS)

    Prigiobbe, V.; Liu, T.; Bryant, S. L.; Hesse, M. A.

    2015-12-01

    The understanding of the transport behaviors in porous media resides on the ability to reproduce fundamental phenomena in a lab setting. Experiments with quasi 2D tanks filled with beads are performed to study physical phenomena induced by chemical and fluid dynamic processes. When an alkaline solution containing heavy metals or radionuclides invades a low pH region, mixing due to longitudinal dispersion induces destabilization of the front forming a fast travelling pulse [1]. When the two fluids travel in parallel, instead, mixing induced by transverse dispersion creates a continuous leakage from the alkaline region into the acidic one forming a fast travelling plume [2] (Figure 1). Impact of these phenomena are on aquifers upon leaking of alkaline fluids, rich in heavy metals and radionuclides, from waste storage sites. Here, we report the results from a study where experiments with a quasi 2D tank are performed to analyze the effect of transverse mixing on strontium (Sr2+) transport. To visualize the leaking plume, a fluorescent dye (Fura-2) is added the acidic solution, which has been widely used in biomedical applications [3]. It is the aim of this work to optimize its application under the conditions relevant to this work. Spectrometric measurements of absorption and fluorescence show sensitivity of the dye to the presence of Sr2+ throughout a broad range of pH and Sr2+ concentration (Figure 2). In the absence of Sr2+, no significant absorption and fluorescence was measured, but as Sr2+ was added the relevant peaks increase significantly and sample dilution of tenfold was required to remain within the measuring threshold. These results show a strong sensitivity of the dye to the cation opening the opportunity to use Fura-2 as a tool to visualize heavy metals and radionuclides plumes. References[1] Prigiobbe et al. (2012) GRL 39, L18401. [2] Prigiobbe and Hesse (2015) in preparation. [3] Xu-Friedman and Regehr (2000) J. Neurosci. 20(12) 4414-4422.

  18. Purification and Characterization of an Extracellular, Thermo-Alkali-Stable, Metal Tolerant Laccase from Bacillus tequilensis SN4

    PubMed Central

    Sondhi, Sonica; Sharma, Prince; Saini, Shilpa; Puri, Neena; Gupta, Naveen

    2014-01-01

    A novel extracellular thermo-alkali-stable laccase from Bacillus tequilensis SN4 (SN4LAC) was purified to homogeneity. The laccase was a monomeric protein of molecular weight 32 KDa. UV-visible spectrum and peptide mass fingerprinting results showed that SN4LAC is a multicopper oxidase. Laccase was active in broad range of phenolic and non-phenolic substrates. Catalytic efficiency (kcat/Km) showed that 2, 6-dimethoxyphenol was most efficiently oxidized by the enzyme. The enzyme was inhibited by conventional inhibitors of laccase like sodium azide, cysteine, dithiothreitol and β-mercaptoethanol. SN4LAC was found to be highly thermostable, having temperature optimum at 85°C and could retain more than 80% activity at 70°C for 24 h. The optimum pH of activity for 2, 6-dimethoxyphenol, 2, 2′-azino bis[3-ethylbenzthiazoline-6-sulfonate], syringaldazine and guaiacol was 8.0, 5.5, 6.5 and 8.0 respectively. Enzyme was alkali-stable as it retained more than 75% activity at pH 9.0 for 24 h. Activity of the enzyme was significantly enhanced by Cu2+, Co2+, SDS and CTAB, while it was stable in the presence of halides, most of the other metal ions and surfactants. The extracellular nature and stability of SN4LAC in extreme conditions such as high temperature, pH, heavy metals, halides and detergents makes it a highly suitable candidate for biotechnological and industrial applications. PMID:24871763

  19. Alkali or alkaline earth metal promoted catalyst and a process for methanol synthesis using alkali or alkaline earth metals as promoters

    DOEpatents

    Tierney, John W.; Wender, Irving; Palekar, Vishwesh M.

    1995-01-01

    The present invention relates to a novel route for the synthesis of methanol, and more specifically to the production of methanol by contacting synthesis gas under relatively mild conditions in a slurry phase with a heterogeneous catalyst comprising reduced copper chromite impregnated with an alkali or alkaline earth metal. There is thus no need to add a separate alkali or alkaline earth compound. The present invention allows the synthesis of methanol to occur in the temperature range of approximately 100.degree.-160.degree. C. and the pressure range of 40-65 atm. The process produces methanol with up to 90% syngas conversion per pass and up to 95% methanol selectivity. The only major by-product is a small amount of easily separated methyl formate. Very small amounts of water, carbon dioxide and dimethyl ether are also produced. The present catalyst combination also is capable of tolerating fluctuations in the H.sub.2 /CO ratio without major deleterious effect on the reaction rate. Furthermore, carbon dioxide and water are also tolerated without substantial catalyst deactivation.

  20. Alkali or alkaline earth metal promoted catalyst and a process for methanol synthesis using alkali or alkaline earth metals as promoters

    DOEpatents

    Tierney, J.W.; Wender, I.; Palekar, V.M.

    1995-01-31

    The present invention relates to a novel route for the synthesis of methanol, and more specifically to the production of methanol by contacting synthesis gas under relatively mild conditions in a slurry phase with a heterogeneous catalyst comprising reduced copper chromite impregnated with an alkali or alkaline earth metal. There is thus no need to add a separate alkali or alkaline earth compound. The present invention allows the synthesis of methanol to occur in the temperature range of approximately 100--160 C and the pressure range of 40--65 atm. The process produces methanol with up to 90% syngas conversion per pass and up to 95% methanol selectivity. The only major by-product is a small amount of easily separated methyl formate. Very small amounts of water, carbon dioxide and dimethyl ether are also produced. The present catalyst combination also is capable of tolerating fluctuations in the H[sub 2]/CO ratio without major deleterious effect on the reaction rate. Furthermore, carbon dioxide and water are also tolerated without substantial catalyst deactivation.

  1. Heavy metal music and reckless behavior among adolescents.

    PubMed

    Arnett, J

    1991-12-01

    Adolescents who liked heavy metal music were compared to those who did not on a variety of outcome variables, particularly focusing on reckless behavior. Boys who liked heavy metal music reported a higher rate of a wide range of reckless behavior, including driving behavior, sexual behavior, and drug use. They were also less satisfied with their family relationships. Girls who liked heavy metal music were more reckless in the areas of shoplifting, vandalism, sexual behavior, and drug use, and reported lower self-esteem. Both boys and girls who liked heavy metal music were higher in sensation seeking and more self-assured with regard to sexuality and dating. In regression analyses, the relation between reckless behavior and liking heavy metal music was sustained for five out of twelve variables concerning reckless behavior, including three of four among girls, when sensation seeking and family relationships were entered into the equation before liking or not liking heavy metal music.

  2. Heavy metal pumps in plants. 1998 annual progress report

    SciTech Connect

    Harper, J.F.

    1998-06-01

    'The purpose of the proposed DOE research is to determine the function of AMA1, a novel heavy metal pump identified in a model plant system, Arabidopsis. Heavy metal pumps belong to a superfamily of P-type ATPases which include the plasma membrane Na/K-ATPase in animals and the plasma membrane H + ATPase in plants and fungi. Heavy metal pumps have been implicated in heavy metal resistance (e.g., cadmium) and regulation of essential micronutrients (e.g., copper). Although several heavy metal pumps have now been identified in plants, their isoform specific functions have not been investigated. The results suggest that AMA1 is a molydenum uptake pump. The authors are exploring the possibility to engineer the ion specificity of these pumps to take up other heavy metals from the soil. This report summarizes work after 2 years of a 3 year project.'

  3. [Bioremediation of heavy metal pollution by edible fungi: a review].

    PubMed

    Liu, Jian-Fei; Hu, Liu-Jie; Liao, Dun-Xiu; Su, Shi-Ming; Zhou, Zheng-Ke; Zhang, Sheng

    2011-02-01

    Bioremediation is the method of using organisms and their derivatives to absorb heavy metals from polluted environment, with the characteristics of low cost, broad sources, and no secondary pollution. Heavy metals enrichment by edible fungi is an important research focus of bioremediation, because it can decrease the eco-toxicity of heavy metals via the uptake by edible fungi, and thereby, take a definite role in heavy metal remediation. This paper reviewed the research progress on the enrichment of heavy metal copper, cadmium, lead, zinc, arsenic, and chromium by edible fungi and the possible enrichment mechanisms, and prospected the development and applications of heavy metal enrichment by edible fungi in the management of polluted environment.

  4. Hyperaccumulators, arbuscular mycorrhizal fungi and stress of heavy metals.

    PubMed

    Miransari, Mohammad

    2011-01-01

    Use of plants, with hyperaccumulating ability or in association with soil microbes including the symbiotic fungi, arbuscular mycorrhiza (AM), are among the most common biological methods of treating heavy metals in soil. Both hyperaccumulating plants and AM fungi have some unique abilities, which make them suitable to treat heavy metals. Hyperaccumulator plants have some genes, being expressed at the time of heavy metal pollution, and can accordingly localize high concentration of heavy metals to their tissues, without showing the toxicity symptoms. A key solution to the issue of heavy metal pollution may be the proper integration of hyperaccumulator plants and AM fungi. The interactions between the soil microbes and the host plant can also be important for the treatment of soils polluted with heavy metals.

  5. Electronic structure and stability of clusters, especially of alkali metals and carbon

    NASA Astrophysics Data System (ADS)

    March, N. H.

    1993-12-01

    The electronic structure of alkali metal atom clusters of various sizes is first discussed, using a spherically averaged pseudopotential model. The main technique employed is density functional theory, and a connection is established with predictions about dissociation energy from the theory of the inhomogeneous electron gas. This latter theory is then invoked explicitly to discuss the barrier to fission for doubly charged alkali metal atom clusters. In the case of asymmetric fission, comparison is made with experiment following the study of Garcias [F. Garcias, J.A. Alonso, J.M. Lopez and M. Barranco, Phys. Rev. B, 43 (1991) 9459], while for symmetric fission a connection is again made between fission barrier and concepts which follow from the general theory of the inhomogeneous electron gas. Finally, and more briefly, both density functional calculations and quantum-chemical studies of carbon clusters are referred to. After a summary of the work of Adamowicz on small linear C clusters [L. Adamowicz, J. Chem. Phys., 94 (1991) 1241], results on C 60 and its singly and doubly charged anions, and on (C 60) 2, are summarized, the potential relevance to alkali doped buckminsterfullerene superconductivity being emphasized as an important direction for future work.

  6. Alkali metal mediated C-C bond coupling reaction

    NASA Astrophysics Data System (ADS)

    Tachikawa, Hiroto

    2015-02-01

    Metal catalyzed carbon-carbon (C-C) bond formation is one of the important reactions in pharmacy and in organic chemistry. In the present study, the electron and hole capture dynamics of a lithium-benzene sandwich complex, expressed by Li(Bz)2, have been investigated by means of direct ab-initio molecular dynamics method. Following the electron capture of Li(Bz)2, the structure of [Li(Bz)2]- was drastically changed: Bz-Bz parallel form was rapidly fluctuated as a function of time, and a new C-C single bond was formed in the C1-C1' position of Bz-Bz interaction system. In the hole capture, the intermolecular vibration between Bz-Bz rings was only enhanced. The mechanism of C-C bond formation in the electron capture was discussed on the basis of theoretical results.

  7. Alkali metal mediated C–C bond coupling reaction

    SciTech Connect

    Tachikawa, Hiroto

    2015-02-14

    Metal catalyzed carbon-carbon (C–C) bond formation is one of the important reactions in pharmacy and in organic chemistry. In the present study, the electron and hole capture dynamics of a lithium-benzene sandwich complex, expressed by Li(Bz){sub 2}, have been investigated by means of direct ab-initio molecular dynamics method. Following the electron capture of Li(Bz){sub 2}, the structure of [Li(Bz){sub 2}]{sup −} was drastically changed: Bz–Bz parallel form was rapidly fluctuated as a function of time, and a new C–C single bond was formed in the C{sub 1}–C{sub 1}′ position of Bz–Bz interaction system. In the hole capture, the intermolecular vibration between Bz–Bz rings was only enhanced. The mechanism of C–C bond formation in the electron capture was discussed on the basis of theoretical results.

  8. Alkali metal mediated C-C bond coupling reaction.

    PubMed

    Tachikawa, Hiroto

    2015-02-14

    Metal catalyzed carbon-carbon (C-C) bond formation is one of the important reactions in pharmacy and in organic chemistry. In the present study, the electron and hole capture dynamics of a lithium-benzene sandwich complex, expressed by Li(Bz)2, have been investigated by means of direct ab-initio molecular dynamics method. Following the electron capture of Li(Bz)2, the structure of [Li(Bz)2](-) was drastically changed: Bz-Bz parallel form was rapidly fluctuated as a function of time, and a new C-C single bond was formed in the C1-C1' position of Bz-Bz interaction system. In the hole capture, the intermolecular vibration between Bz-Bz rings was only enhanced. The mechanism of C-C bond formation in the electron capture was discussed on the basis of theoretical results.

  9. Effects of Alkali Metal Ion Cationization on Fragmentation Pathways of Triazole-Epothilone

    NASA Astrophysics Data System (ADS)

    Duan, Xiyan; Luo, Guoan; Chen, Yue; Kong, Xianglei

    2012-06-01

    The collisionally activated dissociation mass spectra of the protonated and alkali metal cationized ions of a triazole-epothilone analogue were studied in a Fourier transform ion cyclotron resonance mass spectrometer. The fragmentation pathway of the protonated ion was characterized by the loss of the unit of C3H4O3. However, another fragmentation pathway with the loss of C3H2O2 was identified for the complex ions with Na+, K+, Rb+, and Cs+. The branching ratio of the second pathway increases with the increment of the size of alkali metal ions. Theoretical calculations based on density functional theory (DFT) method show the difference in the binding position of the proton and the metal ions. With the increase of the radii of the metal ions, progressive changes in the macrocycle of the compound are induced, which cause the corresponding change in their fragmentation pathways. It has also been found that the interaction energy between the compound and the metal ion decreases with increase in the size of the latter. This is consistent with the experimental results, which show that cesiated complexes readily eject Cs+ when subject to collisions.

  10. Spectroscopic study of promethiumlike bismuth with an electron-beam ion trap: Search for alkali-metal-like resonance lines

    NASA Astrophysics Data System (ADS)

    Kobayashi, Yusuke; Kato, Daiji; Sakaue, Hiroyuki A.; Murakami, Izumi; Nakamura, Nobuyuki

    2014-01-01

    We experimentally settle the three-decades-old question of whether or not promethiumlike heavy ions have strong resonance lines in hot plasmas. In 1980, Curtis and Ellis [Phys. Rev. Lett. 45, 2099 (1980), 10.1103/PhysRevLett.45.2099] predicted that promethiumlike heavy ions should have an alkali-metal structure with a ground-state configuration of 4f145s, and should exhibit strong 5s-5p resonance lines in hot plasmas. However, after many experimental efforts, no clear indication of the predicted resonance lines was found. The work presented herein resolves this question by clearly showing that the predicted resonance lines for bismuth are negligibly weak because of the presence of the [4f135s2]7/2 metastable state, even though the ground-state configuration is 4f145s, as predicted. To obtain these results, we used an electron-beam ion trap that made it possible to exploit a fine-tuned charge-state distribution, and analyzed the experimental spectra with collisional-radiative model calculations.

  11. Energy transfer from PO excited states to alkali metal atoms in the phosphorus chemiluminescence flame

    PubMed Central

    Khan, Ahsan U.

    1980-01-01

    Phosphorus chemiluminescence under ambient conditions of a phosphorus oxidation flame is found to offer an efficient electronic energy transferring system to alkali metal atoms. The lowest resonance lines, 2P3 / 2,½→2S½, of potassium and sodium are excited by energy transfer when an argon stream at 80°C carrying potassium or sodium atoms intersects a phosphorus vapor stream, either at the flame or in the postflame region. The lowest electronically excited metastable 4IIi state of PO or the (PO[unk]PO)* excimer is considered to be the probable energy donor. The (PO[unk]PO)* excimer results from the interaction of the 4IIi state of one PO molecule with the ground 2IIr state of another. Metastability of the donor state is strongly indicated by the observation of intense sensitized alkali atom fluorescence in the postflame region. PMID:16592925

  12. A simple method to estimate relative stabilities of polyethers cationized by alkali metal ions.

    PubMed

    Kuki, Ákos; Nagy, Lajos; Shemirani, Ghazaleh; Memboeuf, Antony; Drahos, László; Vékey, Károly; Zsuga, Miklós; Kéki, Sándor

    2012-02-15

    Dissociation of doubly cationized polyethers, namely [P + 2X](2+) into [P + X](+) and X(+), where P = polyethylene glycol (PEG), polypropylene glycol (PPG) and polytetrahydrofuran (PTHF) and X = Na, K and Cs, was studied by means of energy-dependent collision-induced dissociation tandem mass spectrometry. It was observed that the collision voltage necessary to obtain 50% fragmentation (CV(50)) determined for the doubly cationized polyethers of higher degree of polymerization varied linearly with the number of degrees of freedom (DOF) values. This observation allowed us to correlate these slopes with the corresponding relative gas-phase dissociation energies for binding of alkali ions to polyethers. The relative dissociation energies determined from the corresponding slopes were found to decrease in the order Na(+)  > K(+)  > Cs(+) for each polyether studied, and an order PPG ≈ PEG > PTHF can be established for each alkali metal ion.

  13. Post-Harvest Processing Methods for Reduction of Silica and Alkali Metals in Wheat Straw

    SciTech Connect

    Thompson, David Neal; Lacey, Jeffrey Alan; Shaw, Peter Gordon

    2002-04-01

    Silica and alkali metals in wheat straw limit its use for bioenergy and gasification. Slag deposits occur via the eutectic melting of SiO2 with K2O, trapping chlorides at surfaces and causing corrosion. A minimum melting point of 950°C is desirable, corresponding to SiO2:K2O of about 3:1. Mild chemical treatments were used to reduce Si, K, and Cl, while varying temperature, concentration, %-solids, and time. Dilute acid was more effective at removing K and Cl, while dilute alkali was more effective for Si. Reduction of minerals in this manner may prove economical for increasing utilization of the straw for combustion or gasification.

  14. Post-harvest processing methods for reduction of silica and alkali metals in wheat straw.

    PubMed

    Thompson, David N; Shaw, Peter G; Lacey, Jeffrey A

    2003-01-01

    Silica and alkali metals in wheat straw limit its use for bioenergy and gasification. Slag deposits occur via the eutectic melting of SiO2 with K2O, trapping chlorides at surfaces and causing corrosion. A minimum melting point of 950 degrees C is desirable, corresponding to an SiO2:K2O weight ratio of about 3:1. Mild chemical treatments were used to reduce Si, K, and Cl, while varying temperature, concentration, % solids, and time. Dilute acid was more effective at removing K and Cl, while dilute alkali was more effective for Si. Reduction of minerals in this manner may prove economical for increasing utilization of the straw for combustion or gasification.

  15. Impurity detection in alkali-metal vapor cells via nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Patton, B.; Ishikawa, K.

    2016-11-01

    We use nuclear magnetic resonance spectroscopy of alkali metals sealed in glass vapor cells to perform in situ identification of chemical contaminants. The alkali Knight shift varies with the concentration of the impurity, which in turn varies with temperature as the alloy composition changes along the liquidus curve. Intentional addition of a known impurity validates this approach and reveals that sodium is often an intrinsic contaminant in cells filled with distilled, high-purity rubidium or cesium. Measurements of the Knight shift of the binary Rb-Na alloy confirm prior measurements of the shift's linear dependence on Na concentration, but similar measurements for the Cs-Na system demonstrate an unexpected nonlinear dependence of the Knight shift on the molar ratio. This non-destructive approach allows monitoring and quantification of ongoing chemical processes within the kind of vapor cells which form the basis for precise sensors and atomic frequency standards.

  16. Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils

    PubMed Central

    Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe

    2015-01-01

    Abstract Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline–alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation. PMID:26064038

  17. Removal of dissolved heavy metals and radionuclides by microbial spores

    SciTech Connect

    Revis, N.W.; Hadden, C.T.; Edenborn, H.

    1997-11-01

    Microbial systems have been shown to remove specific heavy metals from contaminated aqueous waste to levels acceptable to EPA for environmental release. However, systems capable of removing a variety of heavy metals from aqueous waste to environmentally acceptable levels remain to be reported. The present studies were performed to determine the specificity of spores of the bacterium Bacillus megaterium for the adsorption of dissolved metals and radionuclides from aqueous waste. The spores effectively adsorbed eight heavy metals from a prepared metal mix and from a plating rinse waste to EPA acceptable levels for waste water. These results suggest that spores have multiple binding sites for the adsorption of heavy metals. Spores were also effective in adsorbing the radionuclides {sup 85}strontium and {sup 197}cesium. The presence of multiple sites in spores for the adsorption of heavy metals and radionuclides makes this biosorbent a good candidate for the treatment of aqueous wastes associated with the plating and nuclear industries. 17 refs., 4 tabs.

  18. Heavy metals in the cell nucleus - role in pathogenesis.

    PubMed

    Sas-Nowosielska, Hanna; Pawlas, Natalia

    2015-01-01

    People are exposed to heavy metals both in an occupational and natural environment. The most pronounced effects of heavy metals result from their interaction with cellular genetic material packed in form of chromatin. Heavy metals influence chromatin, mimicking and substituting natural microelements in various processes taking place in the cell, or interacting chemically with nuclear components: nucleic acids, proteins and lipids. This paper is a review of current knowledge on the effects of heavy metals on chromatin, exerted at the level of various nuclear components.

  19. [Underlying mechanisms of the heavy metal tolerance of mycorrhizal fungi].

    PubMed

    Chen, Bao-Dong; Sun, Yu-Qing; Zhang, Xin; Wu, Song-Lin

    2015-03-01

    Mycorrhizal fungi are ubiquitous in natural ecosystems and can form symbiotic associations with the majority of terrestrial plants. They can be detected even in heavy metal-contaminated soils, while some fungal strains show strong heavy metal tolerance and could potentially be used in bioremediation of contaminated soils. We reviewed current research progresses in the underlying mechanisms of heavy metal tolerance of mycorrhizal fungi, with focuses on habitat selection, physiological adaptation and functional genes. Future research perspectives were proposed to promote the basic research and development of mycorrhizal technology for remediation of heavy metal-contaminated soils.

  20. Structural and Dynamical Trends in Alkali-Metal Silanides Characterized by Neutron-Scattering Methods

    SciTech Connect

    Tang, Wan Si; Dimitrievska, Mirjana; Chotard, Jean-Noël; Zhou, Wei; Janot, Raphaël; Skripov, Alexander V.; Udovic, Terrence J.

    2016-09-29

    Structural, vibrational, and dynamical properties of the mono- and mixed-alkali silanides (MSiH3, where M = K, Rb, Cs, K0.5Rb0.5, K0.5Cs0.5, and Rb0.5Cs0.5) were investigated by various neutron experiments, including neutron powder diffraction (NPD), neutron vibrational spectroscopy (NVS), neutron-scattering fixed-window scans (FWSs), and quasielastic neutron scattering (QENS) measurements. Structural characterization showed that the mixed compounds exhibit disordered (..alpha..) and ordered (..beta..) phases for temperatures above and below about 200-250 K, respectively, in agreement with their monoalkali correspondents. Vibrational and dynamical properties are strongly influenced by the cation environment; in particular, there is a red shift in the band energies of the librational and bending modes with increasing lattice size as a result of changes in the bond lengths and force constants. Additionally, slightly broader spectral features are observed in the case of the mixed compounds, indicating the presence of structural disorder caused by the random distribution of the alkali-metal cations within the lattice. FWS measurements upon heating showed that there is a large increase in reorientational mobility as the systems go through the order-disorder (..beta..-..alpha..) phase transition, and measurements upon cooling of the ..alpha..-phase revealed the known strong hysteresis for reversion back to the ..beta..-phase. Interestingly, at a given temperature, among the different alkali silanide compounds, the relative reorientational mobilities of the SiH3- anions in the ..alpha..- and ..beta..-phases tended to decrease and increase, respectively, with increasing alkali-metal mass. This dynamical result might provide some insights concerning the enthalpy-entropy compensation effect previously observed for these potentially promising hydrogen storage materials.

  1. Peltier effect in normal metal-insulator-heavy fermion metal junctions

    NASA Astrophysics Data System (ADS)

    Goltsev, A. V.; Rowe, D. M.; Kuznetsov, V. L.; Kuznetsova, L. A.; Min, Gao

    2003-04-01

    A theoretical study has been undertaken of the Peltier effect in normal metal-insulator-heavy fermion metal junctions. The results indicate that, at temperatures below the Kondo temperature, such junctions can be used as electronic microrefrigerators to cool the normal metal electrode and are several times more efficient in cooling than the normal metal-heavy fermion metal junctions.

  2. Speciation of phytate ion in aqueous solution. Alkali metal complex formation in different ionic media.

    PubMed

    De Stefano, Concetta; Milea, Demetrio; Pettignano, Alberto; Sammartano, Silvio

    2003-08-01

    The acid-base properties of phytic acid [ myo-inositol 1,2,3,4,5,6-hexakis(dihydrogen phosphate)] (H(12)Phy; Phy(12-)=phytate anion) were studied in aqueous solution by potentiometric measurements ([H+]-glass electrode) in lithium and potassium chloride aqueous media at different ionic strengths (0< I mol L(-1)< or =3) and at t=25 degrees C. The protonation of phytate proved strongly dependent on both ionic medium and ionic strength. The protonation constants obtained in alkali metal chlorides are considerably lower than the corresponding ones obtained in a previous paper in tetraethylammonium iodide (Et(4)NI; e.g., at I=0.5 mol L(-1), log K(3)(H)=11.7, 8.0, 9.1, and 9.1 in Et(4)NI, LiCl, NaCl and KCl, respectively; the protonation constants in Et(4)NI and NaCl were already reported), owing to the strong interactions occurring between the phytate and alkaline cations present in the background salt. We explained this in terms of complex formation between phytate and alkali metal ions. Experimental evidence allows us to consider the formation of 13 mixed proton-metal-ligand complexes, M(j)H(i)Phy((12-i-j)-), (M+ =Li+, Na+, K+), with j< or =7 and i< or =6, in the range 2.5< or =pH< or =10 (some measurements, at low ionic strength, were extended to pH=11). In particular, all the species formed are negatively charged: i+j-12=-5, -6. Very high formation percentages of M+-phytate species are observed in all the pH ranges investigated. The stability of alkali metal complexes follows the trend Li+ > or =Na+K+. Some measurements were also performed at constant ionic strength (I=0.5 mol L(-1)), using different mixtures of Et(4)NI and alkali metal chlorides, in order to confirm the formation of hypothesized and calculated metal-proton-ligand complex species and to obtain conditional protonation constants in these multi-component ionic media.

  3. Subtask 12E1: Compatibility of structural materials in liquid alkali metals

    SciTech Connect

    Natesan, K.; Rink, D.L.; Haglund, R.; Clark, R.W.

    1995-03-01

    The objectives of this task are to (a) evaluate the chemical compatibility of structural alloys such as V-5 wt.%Cr-5 wt.%Ti alloy and Type 316 stainless steel for application in liquid alkali metals such as lithium and sodium-78 wt.% potassium (NaK) at temperatures that are in the range of interest for the International Thermonuclear Experimental Reactor (ITER); (b) evaluate the transfer of nonmetallic elements such as oxygen, nitrogen, carbon, and hydrogen between structural materials and liquid metals; and (c) evaluate the effects of such transfers on the mechanical and microstructural characteristics of the materials for long-term service in liquid-metal environments. Candidate structural materials are being evaluated for their compatibility, interstitial-element transfer, and corrosion in liquid alkali-metal systems such as lithium and NaK. Type 316 stainless steel and V-5Cr-5Ti coupon specimens with and without prealuminizing treatment have been exposed to NaK and lithium environments of commercial purity for times up to 3768 h at temperatures between 300 and 400{degrees}C. 13 refs., 8 figs., 3 tabs.

  4. [Biological activity of selenorganic compounds at heavy metal salts intoxication].

    PubMed

    Rusetskaya, N Y; Borodulin, V B

    2015-01-01

    Possible mechanisms of the antitoxic action of organoselenium compounds in heavy metal poisoning have been considered. Heavy metal toxicity associated with intensification of free radical oxidation, suppression of the antioxidant system, damage to macromolecules, mitochondria and the genetic material can cause apoptotic cell death or the development of carcinogenesis. Organic selenium compounds are effective antioxidants during heavy metal poisoning; they exhibit higher bioavailability in mammals than inorganic ones and they are able to activate antioxidant defense, bind heavy metal ions and reactive oxygen species formed during metal-induced oxidative stress. One of promising organoselenium compounds is diacetophenonyl selenide (DAPS-25), which is characterized by antioxidant and antitoxic activity, under conditions including heavy metal intoxication.

  5. Thermal Characteristics of Hyperaccumulator and Fate of Heavy Metals during Thermal Treatment of Sedum plumbizincicola.

    PubMed

    Zhong, Daoxu; Zhong, Zhaoping; Wu, Longhua; Xue, Hui; Song, Zuwei; Luo, Yongming

    2015-01-01

    Thermal treatment is one of the most promising disposal techniques for heavy metal- (HM)-enriched hyperaccumulators. However, the thermal characteristics and fate of HMs during thermal treatment of hyperaccumulator biomass need to be known in detail. A horizontal tube furnace was used to analyze the disposal process of hyperaccumulator biomass derived from a phyto-extracted field in which the soil was moderately contaminated with heavy metals. Different operational conditions regarding temperature and gas composition were tested. A thermo-dynamic analysis by advanced system for process engineering was performed to predict HM speciation during thermal disposal and SEM-EDS, XRD and sequential chemical extraction were used to characterize the heavy metals. The recovery of Zn, Pb and Cd in bottom ash decreased with increasing temperature but recovery increased in the fly ash. Recovery of Zn, Pb and Cd fluctuated with increasing air flow rate and the metal recovery rates were higher in the fly ash than the bottom ash. Most Cl, S, Fe, Al and SiO2 were found as alkali oxides, SO2, Fe2(SO4)3, iron oxide, Ca3Al2O6, K2SiO3 and SiO2 instead of reacting with HMs. Thus, the HMs were found to occur as the pure metals and their oxides during the combustion process and as the sulfides during the reducing process.

  6. [Environmental geochemical baseline of heavy metals in soils of the Ili river basin and pollution evaluation].

    PubMed

    Zhao, Xin-Ru; Nasier, Telajin; Cheng, Yong-Yi; Zhan, Jiang-Yu; Yang, Jian-Hong

    2014-06-01

    Environmental geochemical baseline models of Cu, Zn, Pb, As, Hg were established by standardized method in the ehernozem, chestnut soil, sierozem and saline soil from the Ili river valley region. The theoretical baseline values were calculated. Baseline factor pollution index evaluation method, environmental background value evaluation method and heavy metal cleanliness evaluation method were used to compare soil pollution degrees. The baseline factor pollution index evaluation showed that As pollution was the most prominent among the four typical types of soils within the river basin, with 7.14%, 9.76%, 7.50% of sampling points in chernozem, chestnut soil and sierozem reached the heavy pollution, respectively. 7.32% of sampling points of chestnut soil reached the permitted heavy metal Pb pollution index in the chestnut soil. The variation extent of As and Pb was the largest, indicating large human disturbance. Environmental background value evaluation showed that As was the main pollution element, followed by Cu, Zn and Pb. Heavy metal cleanliness evaluation showed that Cu, Zn and Pb were better than cleanliness level 2 and Hg was the of cleanliness level 1 in all four types of soils. As showed moderate pollution in sierozem, and it was of cleanliness level 2 or better in chernozem, chestnut soil and saline-alkali soil. Comparing the three evaluation systems, the baseline factor pollution index evaluation more comprehensively reflected the geochemical migration characteristics of elements and the soil formation processes, and the pollution assessment could be specific to the sampling points. The environmental background value evaluation neglected the natural migration of heavy metals and the deposition process in the soil since it was established on the regional background values. The main purpose of the heavy metal cleanliness evaluation was to evaluate the safety degree of soil environment.

  7. Magnesium oxide for improved heavy metals removal

    SciTech Connect

    Schiller, J.E.; Khalafalla, S.E.

    1984-01-01

    To improve technology for treating process water, US Bureau of Mines research has shown that magnesium oxide (MgO) has many advantages over lime or caustic soda for precipitating heavy metals. Sludge produced by MgO occupies only 0.2-0.3 times as much volume as the precipitate made using a soluble base. While a settled, lime-formed precipitate is easily resuspended, the MgO-metal hydroxide sludge becomes cemented together on standing. Settling of the metal hydroxides from a dilute suspension is more complete than precipitates formed with other bases. Virtually any metal that can be precipitated by raising the pH can be treated using MgO. A three-fold to four-fold stoichiometric excess of solid reagent is added. The mixture is reacted for five to 10 minutes. Polymer is added, and settling or filtration completes the process. Because of the greater cost of MgO compared with lime, large-scale practice of this technology will probably be limited to water containing 50 mg/L (3 gr per gal) or less of dissolved metals. For such dilute solutions, chemicals are not a large fraction of total treatment costs, so more desirable sludge properties might justify higher chemical expenses. While the MgO process is technically suitable for widespread application, the extent to which it is adopted will probably be determined by a trade-off between the greater cost of MgO compared with lime and the superior properties of the precipitates and their corresponding ultimate disposal costs.

  8. Emissions of heavy metals into river basins of Germany.

    PubMed

    Scherer, U; Fuchs, S; Behrendt, H; Hillenbrand, T

    2003-01-01

    The input of seven heavy metals (Cd, Cr, Cu, Hg, Ni, Pb and Zn) into the large river basins of Germany via various point and diffuse pathways were estimated for the period of 1985 through 2000. To quantify the emissions via point sources a nationwide survey on heavy metal data of municipal wastewater treatment plants and industrial direct discharges was carried out. The input via diffuse pathways was calculated using an adapted version of the model MONERIS. This model accounts for the significant transport processes, and it includes a Geographical Information System (GIS) that provides digital maps as well as extensive statistical information. For a comparison of the calculated heavy metal emission with the measured heavy metal load at monitoring stations the losses of heavy metals due to retention processes within the river systems have to be considered. Therefore heavy metal retention was calculated according to the retention functions given by Vink and Behrendt. For the large river basins a good correspondence could be found between estimated and measured heavy metal loads in rivers. The total emission into the North Sea decreased for each metal during the period of 1986 to 2000. The reduction varies between 87% for Hg and 41% for Ni mainly caused by the decline via point sources. Today's emissions of heavy metals into river basins of Germany are dominated by the input via diffuse pathways. The most important diffuse emission pathways are "paved urban areas" and "erosion".

  9. Heavy Metal Induced Antibiotic Resistance in Bacterium LSJC7.

    PubMed

    Chen, Songcan; Li, Xiaomin; Sun, Guoxin; Zhang, Yingjiao; Su, Jianqiang; Ye, Jun

    2015-09-29

    Co-contamination of antibiotics and heavy metals prevails in the environment, and may play an important role in disseminating bacterial antibiotic resistance, but the selective effects of heavy metals on bacterial antibiotic resistance is largely unclear. To investigate this, the effects of heavy metals on antibiotic resistance were studied in a genome-sequenced bacterium, LSJC7. The results showed that the presence of arsenate, copper, and zinc were implicated in fortifying the resistance of LSJC7 towards tetracycline. The concentrations of heavy metals required to induce antibiotic resistance, i.e., the minimum heavy metal concentrations (MHCs), were far below (up to 64-fold) the minimum inhibition concentrations (MIC) of LSJC7. This finding indicates that the relatively low heavy metal levels in polluted environments and in treated humans and animals might be sufficient to induce bacterial antibiotic resistance. In addition, heavy metal induced antibiotic resistance was also observed for a combination of arsenate and chloramphenicol in LSJC7, and copper/zinc and tetracycline in antibiotic susceptible strain Escherichia coli DH5α. Overall, this study implies that heavy metal induced antibiotic resistance might be ubiquitous among various microbial species and suggests that it might play a role in the emergence and spread of antibiotic resistance in metal and antibiotic co-contaminated environments.

  10. Heavy Metal Induced Antibiotic Resistance in Bacterium LSJC7

    PubMed Central

    Chen, Songcan; Li, Xiaomin; Sun, Guoxin; Zhang, Yingjiao; Su, Jianqiang; Ye, Jun

    2015-01-01

    Co-contamination of antibiotics and heavy metals prevails in the environment, and may play an important role in disseminating bacterial antibiotic resistance, but the selective effects of heavy metals on bacterial antibiotic resistance is largely unclear. To investigate this, the effects of heavy metals on antibiotic resistance were studied in a genome-sequenced bacterium, LSJC7. The results showed that the presence of arsenate, copper, and zinc were implicated in fortifying the resistance of LSJC7 towards tetracycline. The concentrations of heavy metals required to induce antibiotic resistance, i.e., the minimum heavy metal concentrations (MHCs), were far below (up to 64-fold) the minimum inhibition concentrations (MIC) of LSJC7. This finding indicates that the relatively low heavy metal levels in polluted environments and in treated humans and animals might be sufficient to induce bacterial antibiotic resistance. In addition, heavy metal induced antibiotic resistance was also observed for a combination of arsenate and chloramphenicol in LSJC7, and copper/zinc and tetracycline in antibiotic susceptible strain Escherichia coli DH5α. Overall, this study implies that heavy metal induced antibiotic resistance might be ubiquitous among various microbial species and suggests that it might play a role in the emergence and spread of antibiotic resistance in metal and antibiotic co-contaminated environments. PMID:26426011

  11. Heavy Metals Toxicity and the Environment

    PubMed Central

    Tchounwou, Paul B; Yedjou, Clement G; Patlolla, Anita K; Sutton, Dwayne J

    2013-01-01

    Heavy metals are naturally occurring elements that have a high atomic weight and a density at least 5 times greater than that of water. Their multiple industrial, domestic, agricultural, medical and technological applications have led to their wide distribution in the environment; raising concerns over their potential effects on human health and the environment. Their toxicity depends on several factors including the dose, route of exposure, and chemical species, as well as the age, gender, genetics, and nutritional status of exposed individuals. Because of their high degree of toxicity, arsenic, cadmium, chromium, lead, and mercury rank among the priority metals that are of public health significance. These metallic elements are considered systemic toxicants that are known to induce multiple organ damage, even at lower levels of exposure. They are also classified as human carcinogens (known or probable) according to the U.S. Environmental Protection Agency, and the International Agency for Research on Cancer. This review provides an analysis of their environmental occurrence, production and use, potential for human exposure, and molecular mechanisms of toxicity, genotoxicity, and carcinogenicity. PMID:22945569

  12. Toxic heavy metals: materials cycle optimization.

    PubMed Central

    Ayres, R U

    1992-01-01

    Long-term ecological sustainability is incompatible with an open materials cycle. The toxic heavy metals (arsenic, cadmium, chromium, copper, lead, mercury, silver, uranium/plutonium, zinc) exemplify the problem. These metals are being mobilized and dispersed into the environment by industrial activity at a rate far higher than by natural processes. Apart from losses to the environment resulting from mine wastes and primary processing, many of these metals are utilized in products that are inherently dissipative. Examples of such uses include fuels, lubricants, solvents, fire retardants, stabilizers, flocculants, pigments, biocides, and preservatives. To close the materials cycle, it will be necessary to accomplish two things. The first is to ban or otherwise discourage (e.g., by means of high severance taxes on virgin materials) dissipative uses of the above type. The second is to increase the efficiency of recycling of those materials that are not replaceable in principle. Here, also, economic instruments (such as returnable deposits) can be effective in some cases. A systems view of the problem is essential to assess the cost and effectiveness of alternative strategies. PMID:11607259

  13. Thermochemical Ablation Therapy of VX2 Tumor Using a Permeable Oil-Packed Liquid Alkali Metal

    PubMed Central

    Guo, Ziyi; Zhang, Qiang

    2015-01-01

    Objective Alkali metal appears to be a promising tool in thermochemical ablation, but, it requires additional data on safety is required. The objective of this study was to explore the effectiveness of permeable oil-packed liquid alkali metal in the thermochemical ablation of tumors. Methods Permeable oil-packed sodium–potassium (NaK) was prepared using ultrasonic mixing of different ratios of metal to oil. The thermal effect of the mixture during ablation of muscle tissue ex vivo was evaluated using the Fluke Ti400 Thermal Imager. The thermochemical effect of the NaK-oil mixture on VX2 tumors was evaluated by performing perfusion CT scans both before and after treatment in 10 VX2 rabbit model tumors. VX2 tumors were harvested from two rabbits immediately after treatment to assess their viability using trypan blue and hematoxylin and eosin (H.E.) staining. Results The injection of the NaK–oil mixture resulted in significantly higher heat in the ablation areas. The permeable oil controlled the rate of heat released during the NaK reaction with water in the living tissue. Perfusion computed tomography and its parameter map confirmed that the NaK–oil mixture had curative effects on VX2 tumors. Both trypan blue and H.E. staining showed partial necrosis of the VX2 tumors. Conclusions The NaK–oil mixture may be used successfully to ablate tumor tissue in vivo. With reference to the controlled thermal and chemical lethal injury to tumors, using a liquid alkali in ablation is potentially an effective and safe method to treat malignant tumors. PMID:25885926

  14. Positron binding to alkali-metal hydrides: The role of molecular vibrations

    SciTech Connect

    Gianturco, Franco A.; Franz, Jan; Buenker, Robert J.; Liebermann, Heinz-Peter; Pichl, Lukas; Rost, Jan-Michael; Tachikawa, Masanori; Kimura, Mineo

    2006-02-15

    The bound vibrational levels for J=0 have been computed for the series of alkali-metal hydride molecules from LiH to RbH, including NaH and KH. For all four molecules the corresponding potential-energy curves have been obtained for each isolated species and for its positron-bound complex (e{sup +}XH). It is found that the calculated positron affinity values strongly depend on the molecular vibrational state for which they are obtained and invariably increase as the molecular vibrational energy content increases. The consequences of our findings on the likelihood of possibly detecting such weakly bound species are briefly discussed.

  15. High power density performance of WPt and WRh electrodes in the alkali metal thermoelectric converter

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Jeffries-Nakamura, B.; Underwood, M. L.; Wheeler, B. L.; Loveland, M. E.; Kikkert, S. J.; Lamb, J. L.; Cole, T.; Kummer, J. T.; Bankston, C. P.

    1989-01-01

    The properties of the alkali metal thermoelectric converter (AMTEC) are discussed together with those of an efficient AMTEC electrode. Three groups of electrodes were prepared and tested for their performance as AMTEC electrodes, including WPt-T3, WRh-B1, and WRh-B2. The best electrodes of both WPt and WRh types typically exhibited low porosity, and thickness greater than 0.8 micron, which indicated that transport in these electrodes does not occur by a purely free-molecular flow mode. The observed values of the exchange current were found to be within the range of those observed for oxide-free Mo electrodes under similar conditions.

  16. Metal Hydride and Alkali Halide Opacities in Extrasolar Giant Planets and Cool Stellar Atmospheres

    NASA Technical Reports Server (NTRS)

    Weck, Philippe F.; Stancil, Phillip C.; Kirby, Kate; Schweitzer, Andreas; Hauschildt, Peter H.

    2006-01-01

    The lack of accurate and complete molecular line and continuum opacity data has been a serious limitation to developing atmospheric models of cool stars and Extrasolar Giant Planets (EGPs). We report our recent calculations of molecular opacities resulting from the presence of metal hydrides and alkali halides. The resulting data have been included in the PHOENIX stellar atmosphere code (Hauschildt & Baron 1999). The new models, calculated using spherical geometry for all gravities considered, also incorporate our latest database of nearly 670 million molecular lines, and updated equations of state.

  17. Hydroponic phytoremediation of heavy metals and radionuclides

    SciTech Connect

    Hartong, J.; Szpak, J.; Hamric, T.; Cutright, T.

    1998-07-01

    It is estimated that the Departments of Defense, Energy, and Agriculture will spend up to 300 billion federal dollars on environmental remediation during the next century. Current remediation processes can be expensive, non-aesthetic, and non-versatile. Therefore, the need exists for more innovative and cost effective solutions. Phytoremediation, the use of vegetation for the remediation of contaminated sediments, soils, and ground water, is an emerging technology for treating several categories of persistent, toxic contaminants. Although effective, phytoremediation is still in a developmental stage, and therefore is not a widely accepted technology by regulatory agencies and public groups. Research is currently being conducted to validate the processes effectiveness as well as increase regulatory and community acceptance. This research will focus on the ability of plants to treat an aquifer contaminated with heavy metals and radionuclides. Specifically, the effectiveness of hydroponically grown dwarf sunflowers and mustard seed will be investigated.

  18. Plant productivity and heavy metal contamination

    SciTech Connect

    Guidi, G.V.; Petruzzelli, G.; Vallini, G.; Pera, A.

    1990-06-01

    This article describes the potential for use of composts from green waste and from municipal solid wastes for agricultural use in Italy. The accumulation of heavy metals in compost-amended soils and crops was evaluated and the influence of these composts on plant productivity was studied. Green compost was obtained from vegetable organic residues; municipal solid waste derived compost was obtained from the aerobic biostabilization of a mixture of the organic biodegradable fraction of municipal solid waste and sewage sludge. The two composts had good chemical characteristics and their use caused no pollution to soil and plants. The overall fertilizing effect was higher for green compost even though green compost and municipal solid waste derived compost had similar contents of primary elements of fertility.

  19. Heavy Metals Resisting Gravity in White Dwarfs?

    NASA Astrophysics Data System (ADS)

    Rauch, T.; Gamrath, S.; Quinet, P.; Hoyer, D.; Werner, K.; Kruk, J. W.

    2017-03-01

    Spectral lines of heavy metals, identified in high-resolution ultraviolet spectra of the DO-type white dwarf RX J0503.9–2854 (RE 0503–289), allow precise abundance determinations of these species by means of advanced non-local thermodynamic equilibrium stellar-atmosphere models – provided that reliable atomic data is available. Such analyses of Zn (atomic number Z = 30), Ga (31), Ge (32), As (33), Mo (42), Kr (36), Zr (40), Xe (54), and Ba (56) have recently shown that, without exception, their abundances are unexpectedly strongly supersolar (up to about 5 dex). This is much higher than predicted by recent asymptotic giant branch nucleosynthesis calculations. Thus, the interplay of gravitational settling and radiative levitation may play an important role for their photospheric prominence.

  20. Heavy Metal Music and Adolescent Suicidality: An Empirical Investigation.

    ERIC Educational Resources Information Center

    Scheel, Karen R.; Westefeld, John S.

    1999-01-01

    Investigates the relationship between preference for heavy metal music and vulnerability to suicide among high school students. Results indicate that preference for heavy metal music among adolescents may be sign of increased suicidal vulnerability, but also suggests that the source of the problem may lie more in personal and familial…

  1. Species sensitivity analysis of heavy metals to freshwater organisms.

    PubMed

    Xin, Zheng; Wenchao, Zang; Zhenguang, Yan; Yiguo, Hong; Zhengtao, Liu; Xianliang, Yi; Xiaonan, Wang; Tingting, Liu; Liming, Zhou

    2015-10-01

    Acute toxicity data of six heavy metals [Cu, Hg, Cd, Cr(VI), Pb, Zn] to aquatic organisms were collected and screened. Species sensitivity distributions (SSD) curves of vertebrate and invertebrate were constructed by log-logistic model separately. The comprehensive comparisons of the sensitivities of different trophic species to six typical heavy metals were performed. The results indicated invertebrate taxa to each heavy metal exhibited higher sensitivity than vertebrates. However, with respect to the same taxa species, Cu had the most adverse effect on vertebrate, followed by Hg, Cd, Zn and Cr. When datasets from all species were included, Cu and Hg were still more toxic than the others. In particular, the toxicities of Pb to vertebrate and fish were complicated as the SSD curves of Pb intersected with those of other heavy metals, while the SSD curves of Pb constructed by total species no longer crossed with others. The hazardous concentrations for 5 % of the species (HC5) affected were derived to determine the concentration protecting 95 % of species. The HC5 values of the six heavy metals were in the descending order: Zn > Pb > Cr > Cd > Hg > Cu, indicating toxicities in opposite order. Moreover, potential affected fractions were calculated to assess the ecological risks of different heavy metals at certain concentrations of the selected heavy metals. Evaluations of sensitivities of the species at various trophic levels and toxicity analysis of heavy metals are necessary prior to derivation of water quality criteria and the further environmental protection.

  2. Heavy metals alter the potency of medicinal plants.

    PubMed

    Nasim, Sekh Abdul; Dhir, Bhupinder

    2010-01-01

    There has been increased use of herbal drugs in recent years. Because of increasing demand and wider use, it is essential that the quality of plant-based drugs should be assured prior to use. When heavy metals contaminate the plants from which herbal drugs are derived, they affect both plant growth characteristics and production of secondary plant metabolites. Plants exposed to heavy metal stress show changes in production of secondary metabolites. High levels of heavy metal contamination in medicinal or other plants may suppress secondary metabolite production. Alternatively, the presence of heavy metals in medicinal plants may stimulate production of bioactive compounds in many plant species. Moreover, some research results suggest that heavy metals may play an important role in triggering plant genes to alter the titers or nature of secondary plant metabolites, although the exact mechanism by which this happens remains unclear. Oxidative stress induced by heavy metals triggers signaling pathways that affect production of specific plant metabolites. In particular, reactive oxygen species (ROS), generated during heavy metal stress, may cause lipid peroxidation that stimulates formation of highly active signaling compounds capable of triggering production of bioactive compounds (secondary metabolites) that enhances the medicinal value of the plant. As usual, further research is needed to clarify the mechanism by which heavy metals induce responses that result in enhanced secondary metabolite production.

  3. Heavy Metal Music and Reckless Behavior among Adolescents.

    ERIC Educational Resources Information Center

    Arnett, Jeffrey

    1991-01-01

    Fifty-four male and 30 female adolescents who like heavy metal music were compared on various outcome variables to 56 male and 105 female peers who do not like it. Those who like heavy metal report a wider range of reckless behavior than those who do not like it. (SLD)

  4. Heavy Metal Toxicity in Bioremediation: Microbial Cultures and Microscopy.

    DTIC Science & Technology

    1997-12-01

    This research employed a variety of microscopy and spread plating techniques to observe the effects of heavy metal treatments on a toluene-selected...of bacteria and offered new techniques for potential heavy metal toxicity measurements as well as differentiation methods.

  5. A Process for Making Bulk Heavy Metal Fluoride Glasses.

    DTIC Science & Technology

    This invention relates to the preparation of glasses, and, in particular, relates to the preparation of heavy metal fluoride glasses with...reproducible high optical qualities. Considerable effort has been expended to develop heavy metal fluoride glasses ( HMFG ) as a viable family of infrared

  6. Heavy metal retention of different roadside soils

    NASA Astrophysics Data System (ADS)

    Werkenthin, Moritz; Kluge, Björn; Wessolek, Gerd

    2014-05-01

    Emissions from major highways contain different kinds of contaminants such as heavy metals, polycyclic aromatic hydrocarbons and road salts which can occur in both particulate and dissolved form. Pollutants are transferred to the environment via aerial transport or the infiltration of road runoff and spray water. A significant rate of the road runoff infiltrates into the Embankment which is usually built during road construction and located next to the road edge. Especially in the long term development there is an increasing problem of soil contamination and groundwater pollution. According to valid German law, newly constructed hard shoulders have to provide a specific bear-ing capacity to enable trafficability in emergency cases. Therefore the applicable materials consist of accurately defined gravel-soil mixtures, which can fulfil this requirement. To determine and com-pare the total and dissolved concentrations of Pb, Cd, Zn, Cu, Ni, Cr in the road runoff and seep-age water of newly constructed embankments, we installed 6 Lysimeter along the edge of the German highway A115. Three lysimeter were filled with different materials which are recently used for embankment construction in Germany. Three further lysimeter where installed and filled with plain gravel, to observe the distribution, quantity and quality of road runoff. Fist results showed that heavy metal concentrations determined in the road runoff were compara-ble to literature values. The solute concentrations in the seepage water of the different embank-ment materials do not show considerable differences and exceed the trigger values of the German Federal Soil Protection & Contamination Ordinance (BBodSchV) only sporadically. Total concentra-tions of the seepage water are significantly higher than solute concentrations and clearly differ be-tween stable and non stable variant. In order to estimate the risk of groundwater pollution further monitoring of seepage water quality is necessary.

  7. Structures of alkali metals in silica gel nanopores: new materials for chemical reductions and hydrogen production.

    PubMed

    Shatnawi, Mouath; Paglia, Gianluca; Dye, James L; Cram, Kevin C; Lefenfeld, Michael; Billinge, Simon J L

    2007-02-07

    Alkali metals and their alloys can be protected from spontaneous reaction with dry air by intercalation (with subsequent heating) into the pores of silica gel (SG) at loadings up to 40 wt %. The resulting loose, black powders are convenient materials for chemical reduction of organic compounds and the production of clean hydrogen. The problem addressed in this paper is the nature of the reducing species present in these amorphous materials. The atomic pair distribution function (PDF), which considers both Bragg and diffuse scattering components, was used to examine their structures. Liquid Na-K alloys added to silica gel at room temperature (stage 0) or heated to 150 degrees C (stage I) as well as stage I Na-SG, retain the overall pattern of pure silica gel. Broad oscillations in the PDF show that added alkali metals remain in the pores as nanoscale metal clusters. 23Na MAS NMR studies confirm the presence of Na(0) and demonstrate that Na+ ions are formed as well. The relative amounts of Na(0) and Na(+) depend on both the overall metal loading and the average pore size. The results suggest that ionization occurs near or in the SiO2 walls, with neutral metal present in the larger cavities. The fate of the electrons released by ionization is uncertain, but they may add to the silica gel lattice, or form an "electride-like plasma" near the silica gel walls. A remaining mystery is why the stage I material does not show a melting endotherm of the encapsulated metal and does not react with dry oxygen. Na-SG when heated to 400 degrees C (stage II) yields a dual-phase reaction product that consists of Na(4)Si(4) and Na(2)SiO(3).

  8. Heavy metal pollution in lentic ecosystem of sub-tropical industrial region and its phytoremediation.

    PubMed

    Rai, Prabhat Kumar

    2010-03-01

    Metals and several physicochemical parameters, from four sampling sites in a tropical lake receiving the discharges from a thermal power plant, a coal mine and a chlor-alkali industry, were studied from 2004-2005. Pertaining to metal pollution, the site most polluted with heavy metals was Belwadah, i.e., waters and sediments had the highest concentration of all the metals examined. The reference site was characterized by the presence of low concentrations of metals in waters and in sediments. Further, several wetland plants were harvested from different sites, and simultaneously, these were assessed for their metal concentration efficiency. Following the water quality monitoring and metal concentration efficiency, two-month field phytoremediation experiments were conducted using large enclosures at the discharge point of different polluted sites of the lake. Eichhornia crassipes, Lemna minor, and Azolla pinnata were frontier metal accumulators hence selected for previously mentioned field phytoremediation experiments. During field phytoremediation experiments using aquatic macrophytes, marked percentage reduction in metals concentrations were recorded. The percentage decrease for different metals was in the range of 25-67.90% at Belwadah (with Eichhornia crassipes and Lemna minor), 25-77.14% at Dongia nala (with Eichhornia crassipes, Lemna minor, and Azolla pinnata) and 25-71.42% at Ash pond site of G.B. Pant Sagar (with Lemna minor and Azolla pinnata). Preliminary studies of polluted sites are therefore useful for improved microcosm design and for the systematic extrapolation of information from experimental ecosystems to natural ecosystems.

  9. Removal of heavy metal ions from wastewaters: a review.

    PubMed

    Fu, Fenglian; Wang, Qi

    2011-03-01

    Heavy metal pollution has become one of the most serious environmental problems today. The treatment of heavy metals is of special concern due to their recalcitrance and persistence in the environment. In recent years, various methods for heavy metal removal from wastewater have been extensively studied. This paper reviews the current methods that have been used to treat heavy metal wastewater and evaluates these techniques. These technologies include chemical precipitation, ion-exchange, adsorption, membrane filtration, coagulation-flocculation, flotation and electrochemical methods. About 185 published studies (1988-2010) are reviewed in this paper. It is evident from the literature survey articles that ion-exchange, adsorption and membrane filtration are the most frequently studied for the treatment of heavy metal wastewater.

  10. Dietary heavy metal uptake by the least shrew, Cryptotis parva

    SciTech Connect

    Brueske, C.C.; Barrett, G.W. )

    1991-12-01

    Heavy metals from sewage sludge have been reported to concentrate in producers, in primary consumers, and in detritivores. Little research, however, has focused on the uptake of heavy metals from sewage sludge by secondary consumers. The Family Soricidae represents an ideal mammalian taxonomic group to investigate rates of heavy metal transfer between primary and secondary consumers. The least shrew (Cryptotis parva) was used to evaluate the accumulation of heavy metals while maintained on a diet of earthworms collected from long-term sludge-treated old-field communities. This secondary consumer is distributed widely through the eastern United States and its natural diet includes earthworms which makes it a potentially good indicator of heavy metal transfer in areas treated with municipal sludge.

  11. Reducing hazardous heavy metal ions using mangium bark waste.

    PubMed

    Khabibi, Jauhar; Syafii, Wasrin; Sari, Rita Kartika

    2016-08-01

    The objective of this study was to evaluate the characteristics of mangium bark and its biosorbent ability to reduce heavy metal ions in standard solutions and wastewater and to assess changes in bark characteristics after heavy metal absorption. The experiments were conducted to determine heavy metal absorption from solutions of heavy metals alone and in mixtures as well as from wastewater. The results show that mangium bark can absorb heavy metals. Absorption percentages and capacities from single heavy metal solutions showed that Cu(2+) > Ni(2+) > Pb(2+) > Hg(2+), while those from mixture solutions showed that Hg(2+) > Cu(2+) > Pb(2+) > Ni(2+). Wastewater from gold mining only contained Cu, with an absorption percentage and capacity of 42.87 % and 0.75 mg/g, respectively. The highest absorption percentage and capacity of 92.77 % and 5.18 mg/g, respectively, were found for Hg(2+) in a mixture solution and Cu(2+) in single-metal solution. The Cu(2+) absorption process in a single-metal solution changed the biosorbent characteristics of the mangium bark, yielding a decreased crystalline fraction; changed transmittance on hydroxyl, carboxyl, and carbonyl groups; and increased the presence of Cu. In conclusion, mangium bark biosorbent can reduce hazardous heavy metal ions in both standard solutions and wastewater.

  12. Characterisation of heavy metal discharge into the Ria of Huelva.

    PubMed

    Sainz, A; Grande, J A; de la Torre, M L

    2004-06-01

    The Ria of Huelva estuary, in SW Spain, is known to be one of the most heavy metal contaminated estuaries in the world. River contribution to the estuary of dissolved Cu, Zn, Mn, Cr, Ni, Cd, and As were analysed for the period 1988-2001. The obtained mean values show that this contribution, both because of the magnitude of total metals (895.1 kg/h), composition, toxicity (8.7 kg/h of As+Cd+Pb) and persistence, is an incomparable case in heavy metal contamination of estuaries. The amount and typology of heavy metal discharge to the Ria of Huelva are related to freshwater flow (and, consequently, to rainfall); as a result, two different types of heavy metal discharge can be distinguished in the estuary: during low water (50% of the days), with only 19.3 kg/h of heavy metals, and during high water or flood (17% of the days), where daily maximum discharge of 72,475 kg of heavy metals were recorded, from which 1481 kg were of As, 470 kg of Pb, and 170 kg of Cd. In the most frequent situation (77% of the days), the Odiel River discharges from 90% to 100% of the freshwater received by the estuary. Despite this, the high concentration of heavy metals in the Tinto River water causes this river to discharge into the Ria of Huelva 12.5% of fluvial total dissolved metal load received by the estuary.

  13. Bioindication of a surplus of heavy metals in terrestrial ecosystems.

    PubMed

    Ernst, W H; Verkleij, J A; Vooijs, R

    1983-09-01

    A survey of the methods of boindication of heavy metals in terrestrial ecosystems and their effectiveness for predicting the consequences of environmental stress on organisms is presented. Two main inputs of heavy metals for terrestrial ecosystems have been considered: airborne and soil-borne.Airborne metals can be monitored due to physical adsorption on plant surfaces or due to chemical exchange processes in cell walls. Active biomonitoring widely uses both aspects, however, without predictive values.Meaningful bioindication of soilborne heavy metals can only be achieved by passive monitoring. Due to the different functions of heavy metals in organisms-micronutrients and trace elements-the knowledge of natural background values is important, considering the qualitative aspects of metals in the soil. In exceptional situations morphological and anatomical changes of plant organs will facilitate bioindication; in every case chemical analysis of the concentration of heavy metals is an essential part of the monitoring program.A long-term exposure of organisms to heavy metals will influence the genetic structure of populations. Therefore measurement of heavy metal tolerance of plants has to be a standard procedure in monitoring programs.

  14. [Beijing common green tree leaves' accumulation capacity for heavy metals].

    PubMed

    Li, Shao-Ning; Kong, Ling-Wei; Lu, Shao-Wei; Chen, Bo; Gao, Chen; Shi, Yuan

    2014-05-01

    Seasonal variation of heavy metal contents in leaves and their relationships with soil heavy metal pollution levels were studied through measuring and analyzing the leaves of the common tree species in Beijing and soil heavy metal contents, to detect heavy metal accumulation ability of plant leaves. The results showed that: (1) the contents of Cu, Pb, Zn in plant leaves first decreased and then increased, again declined with changing the seasons (from spring to winter). Cr concentration showed the trend of first increase and then decrease from spring to winter, and the highest in the autumn; the accumulation capacities of Cu for Babylonica and Japonica were higher in the spring, summer and autumn, while Tabuliformis was in winter; the higher accumulation capacities for Cr, Pb were Japonica and Platycladus, and in winter were Platycladus and Bungeana; the higher accumulation capacities for Zn were Babylonica and Bungeana, while Platycladus in winter; (2) the pollution degree of four kinds of heavy metals (Cu, Cr, Pb, Zn) from downtown to suburbs showed that: Jingshan (C =2.48, C is contamination factor) > Olympic (C = 1.27) > Songshan (C = 1.20) > Shuiguan (C = 1. 18); (3) the heavy metals concentration of same plant leaves in the water of the Great Wall changed larger, but those in the other three areas showed that: Jingshan > Olympic > Songshan; the ability of same species leaf to absorb different sorts of heavy metals showed that: Zn >Cu >Pb >Cr; the difference between Zn content and Cr content was significant (P <0.01); (4) the relationship between heavy metal content in plant leaves and soil heavy metal pollution levels presented a quadratic polynomial relation; the significant correlation was found between other three heavy metal contents of plant samples and soil samples, but they were not the case for the Cu, and the correlation coefficients were above 0. 9.

  15. Bond-length distributions for ions bonded to oxygen: alkali and alkaline-earth metals

    PubMed Central

    Gagné, Olivier Charles; Hawthorne, Frank Christopher

    2016-01-01

    Bond-length distributions have been examined for 55 configurations of alkali-metal ions and 29 configurations of alkaline-earth-metal ions bonded to oxygen, for 4859 coordination polyhedra and 38 594 bond distances (alkali metals), and for 3038 coordination polyhedra and 24 487 bond distances (alkaline-earth metals). Bond lengths generally show a positively skewed Gaussian distribution that originates from the variation in Born repulsion and Coulomb attraction as a function of interatomic distance. The skewness and kurtosis of these distributions generally decrease with increasing coordination number of the central cation, a result of decreasing Born repulsion with increasing coordination number. We confirm the following minimum coordination numbers: [3]Li+, [3]Na+, [4]K+, [4]Rb+, [6]Cs+, [3]Be2+, [4]Mg2+, [6]Ca2+, [6]Sr2+ and [6]Ba2+, but note that some reported examples are the result of extensive dynamic and/or positional short-range disorder and are not ordered arrangements. Some distributions of bond lengths are distinctly multi-modal. This is commonly due to the occurrence of large numbers of structure refinements of a particular structure type in which a particular cation is always present, leading to an over-representation of a specific range of bond lengths. Outliers in the distributions of mean bond lengths are often associated with anomalous values of atomic displacement of the constituent cations and/or anions. For a sample of [6]Na+, the ratio U eq(Na)/U eq(bonded anions) is partially correlated with 〈[6]Na+—O2−〉 (R 2 = 0.57), suggesting that the mean bond length is correlated with vibrational/displacement characteristics of the constituent ions for a fixed coordination number. Mean bond lengths also show a weak correlation with bond-length distortion from the mean value in general, although some coordination numbers show the widest variation in mean bond length for zero distortion, e.g. Li+ in [4]- and [6]-coordination, Na+ in [4]- and [6

  16. Heavy metals in Tuskegee Lake crayfish

    SciTech Connect

    Khan, A.T.

    1995-12-31

    The crayfish, Onconectes virifis, is a bottom dweller and eats insect larvae, worms, crustaceans, small snails, fishes, and dead animal matter. They can be used to monitor the aquatic environment such as lakes, ponds and creeks. To monitor the environmental contamination of heavy metals (Hg, Pb, Cd, Cu, Co, Ni, and Zn) in Tuskegee Lake, Tuskegee, Alabama, adult crayfish were collected and analyzed for these metals. The Pb, Cd, Cu, Ni, and Zn concentrations were 3.91, 0.22, 8.06, 1.11, and 33.37 ppm in muscle and 28.98, 1.15, 9.86, 2.1 8, and 32.62 ppm in exoskeleton of crayfish, respectively. The concentrations of Pb and Cd were significantly higher in exoskeleton than those of muscle. However, the concentrations of Cu, Ni, and Zn did not show any significant difference between the muscle and the exoskeleton of the crayfish. The concentrations of Hg and Co were undetected in both the exoskeleton and muscle of the crayfish.

  17. Remediation technologies for heavy metal contaminated groundwater.

    PubMed

    Hashim, M A; Mukhopadhyay, Soumyadeep; Sahu, Jaya Narayan; Sengupta, Bhaskar

    2011-10-01

    The contamination of groundwater by heavy metal, originating either from natural soil sources or from anthropogenic sources is a matter of utmost concern to the public health. Remediation of contaminated groundwater is of highest priority since billions of people all over the world use it for drinking purpose. In this paper, thirty five approaches for groundwater treatment have been reviewed and classified under three large categories viz chemical, biochemical/biological/biosorption and physico-chemical treatment processes. Comparison tables have been provided at the end of each process for a better understanding of each category. Selection of a suitable technology for contamination remediation at a particular site is one of the most challenging job due to extremely complex soil chemistry and aquifer characteristics and no thumb-rule can be suggested regarding this issue. In the past decade, iron based technologies, microbial remediation, biological sulphate reduction and various adsorbents played versatile and efficient remediation roles. Keeping the sustainability issues and environmental ethics in mind, the technologies encompassing natural chemistry, bioremediation and biosorption are recommended to be adopted in appropriate cases. In many places, two or more techniques can work synergistically for better results. Processes such as chelate extraction and chemical soil washings are advisable only for recovery of valuable metals in highly contaminated industrial sites depending on economical feasibility.

  18. Alkali metal-cationized serine clusters studied by sonic spray ionization tandem mass spectrometry.

    PubMed

    Nanita, Sergio C; Sokol, Ewa; Cooks, R Graham

    2007-05-01

    Serine solutions containing salts of alkali metals yield magic number clusters of the type (Ser(4)+C)(+), (Ser(8)+C)(+), (Ser(12)+C)(+), and (Ser(17)+2C)(+2) (where C = Li(+), Na(+), K(+), Rb(+), or Cs(+)), in relative abundances which are strongly dependent on the cation size. Strong selectivity for homochirality is involved in the formation of serine tetramers cationized by K(+), Rb(+), and Cs(+). This is also the case for the octamers cationized by the smaller alkalis but there is a strong preference for heterochirality in the octamers cationized by the larger alkali cations. Tandem mass spectrometry shows that the octamers and dodecamers cationized by K(+), Rb(+), and Cs(+) dissociate mainly by the loss of Ser(4) units, suggesting that the neutral tetramers are the stable building blocks of the observed larger aggregates, (Ser(8)+C)(+) and (Ser(12)+C)(+). Remarkably, although the Ser(4) units are formed with a strong preference for homochirality, they aggregate further regardless of their handedness and, therefore, with a preference for the nominally racemic 4D:4L structure and an overall strong heterochiral preference. The octamers cationized by K(+), Rb(+), or Cs(+) therefore represent a new type of cluster ion that is homochiral in its internal subunits, which then assemble in a random fashion to form octamers. We tentatively interpret the homochirality of these tetramers as a consequence of assembly of the serine molecules around a central metal ion. The data provide additional evidence that the neutral serine octamer is homochiral and is readily cationized by smaller ions.

  19. A Study of the Hydration of the Alkali Metal Ions in Aqueous Solution

    PubMed Central

    2011-01-01

    The hydration of the alkali metal ions in aqueous solution has been studied by large angle X-ray scattering (LAXS) and double difference infrared spectroscopy (DDIR). The structures of the dimethyl sulfoxide solvated alkali metal ions in solution have been determined to support the studies in aqueous solution. The results of the LAXS and DDIR measurements show that the sodium, potassium, rubidium and cesium ions all are weakly hydrated with only a single shell of water molecules. The smaller lithium ion is more strongly hydrated, most probably with a second hydration shell present. The influence of the rubidium and cesium ions on the water structure was found to be very weak, and it was not possible to quantify this effect in a reliable way due to insufficient separation of the O–D stretching bands of partially deuterated water bound to these metal ions and the O–D stretching bands of the bulk water. Aqueous solutions of sodium, potassium and cesium iodide and cesium and lithium hydroxide have been studied by LAXS and M–O bond distances have been determined fairly accurately except for lithium. However, the number of water molecules binding to the alkali metal ions is very difficult to determine from the LAXS measurements as the number of distances and the temperature factor are strongly correlated. A thorough analysis of M–O bond distances in solid alkali metal compounds with ligands binding through oxygen has been made from available structure databases. There is relatively strong correlation between M–O bond distances and coordination numbers also for the alkali metal ions even though the M–O interactions are weak and the number of complexes of potassium, rubidium and cesium with well-defined coordination geometry is very small. The mean M–O bond distance in the hydrated sodium, potassium, rubidium and cesium ions in aqueous solution have been determined to be 2.43(2), 2.81(1), 2.98(1) and 3.07(1) Å, which corresponds to six-, seven-, eight- and

  20. Alkali metal carbon dioxide electrochemical system for energy storage and/or conversion of carbon dioxide to oxygen

    NASA Astrophysics Data System (ADS)

    Hagedorn, Norman H.

    1993-05-01

    An alkali metal, such as lithium, is the anodic reactant; carbon dioxide or a mixture of carbon dioxide and carbon monoxide is the cathodic reactant; and carbonate of the alkali metal is the electrolyte in an electrochemical cell for the storage and delivery of electrical energy. Additionally, alkali metal-carbon dioxide battery systems include a plurality of such electrochemical cells. Gold is a preferred catalyst for reducing the carbon dioxide at the cathode. The fuel cell of the invention produces electrochemical energy through the use of an anodic reactant which is extremely energetic and light, and a cathodic reactant which can be extracted from its environment and therefore exacts no transportation penalty. The invention is, therefore, especially useful in extraterrestrial environments.

  1. Alkali metal carbon dioxide electrochemical system for energy storage and/or conversion of carbon dioxide to oxygen

    NASA Astrophysics Data System (ADS)

    Hagedorn, Norman H.

    1991-09-01

    An alkali metal, such as lithium, is the anodic reactant, carbon dioxide or a mixture of carbon dioxide and carbon monoxide is the cathodic reactant, and carbonate of the alkali metal is the electrolyte in an electrochemical cell for the storage and delivery of electrical energy. Additionally, alkali metal-carbon dioxide battery systems include a plurality of such electrochemical cells. Gold is a preferred catalyst for reducing the carbon dioxide at the cathode. The fuel cell of the invention produces electrochemical energy through the use of an anodic reactant which is extremely energetic and light, and a cathodic reactant which can be extracted from its environment and therefore exacts no transportation penalty. The invention is therefore especially useful in extraterrestrial environments.

  2. A study on optical properties of poly (ethylene oxide) based polymer electrolyte with different alkali metal iodides

    NASA Astrophysics Data System (ADS)

    Rao, B. Narasimha; Suvarna, R. Padma

    2016-05-01

    Polymer electrolytes were prepared by adding poly (ethylene glycol) dimethyl ether (PEGDME), TiO2 (nano filler), different alkali metal iodide salts RI (R+=Li+, Na+, K+, Rb+, Cs+) and I2 into Acetonitrile gelated with Poly (ethylene oxide) (PEO). Optical properties of poly (ethylene oxide) based polymer electrolytes were studied by FTIR, UV-Vis spectroscopic techniques. FTIR spectrum reveals that the alkali metal cations were coordinated to ether oxygen of PEO. The optical absorption studies were made in the wavelength range 200-800 nm. It is observed that the optical absorption increases with increase in the radius of alkali metal cation. The optical band gap for allowed direct transitions was evaluated using Urbach-edges method. The optical properties such as optical band gap, refractive index and extinction coefficient were determined. The studied polymer materials are useful for solar cells, super capacitors, fuel cells, gas sensors etc.

  3. Direct surface charging and alkali-metal doping for tuning the interlayer magnetic order in planar nanostructures

    NASA Astrophysics Data System (ADS)

    Dasa, Tamene R.; Stepanyuk, Valeri S.

    2015-08-01

    The continuous reduction of magnetic units to ultrasmall length scales inspires efforts to look for a suitable means of controlling magnetic states. In this study, we show two surface charge alteration techniques for tuning the interlayer exchange coupling of ferromagnetic layers separated by paramagnetic spacers. Our ab initio study reveals that already a modest amount of extra charge can switch the mutual alignment of the magnetization from antiferromagnetic to ferromagnetic or vice versa. We also propose adsorption of alkali metals as an alternative way of varying the electronic and chemical properties of magnetic surfaces. Clear evidence is found that the interlayer magnetic order can be reversed by adsorbing alkali metals on the magnetic layer. Moreover, alkali-metal overlayers strongly enhance the perpendicular magnetic anisotropy in FePt thin films. These findings combined with atomistic spin model calculations suggest that the electronic or ionic way of surface charging can have a crucial role for magnetic hardening and spin state control.

  4. Coordination effect-regulated CO2 capture with an alkali metal onium salts/crown ether system

    SciTech Connect

    Yang, Zhen-Zhen; Jiang, Deen; Zhu, Xiang; Tian, Chengcheng; Brown, Suree; Do-Thanh, Chi-Linh; He, Liang-Nian; Dai, Sheng

    2014-01-01

    A coordination effect was employed to realize equimolar CO2 absorption, adopting easily synthesized amino group containing absorbents (alkali metal onium salts). The essence of our strategy was to increase the steric hindrance of cations so as to enhance a carbamic acid pathway for CO2 capture. Our easily synthesized alkali metal amino acid salts or phenolates were coordinated with crown ethers, in which highly sterically hindered cations were obtained through a strong coordination effect of crown ethers with alkali metal cations. For example, a CO2 capacity of 0.99 was attained by potassium prolinate/18-crown-6, being characterized by NMR, FT-IR, and quantum chemistry calculations to go through a carbamic acid formation pathway. The captured CO2 can be stripped under very mild conditions (50 degrees C, N-2). Thus, this protocol offers an alternative for the development of technological innovation towards efficient and low energy processes for carbon capture and sequestration.

  5. Alkali metal carbon dioxide electrochemical system for energy storage and/or conversion of carbon dioxide to oxygen

    NASA Technical Reports Server (NTRS)

    Hagedorn, Norman H. (Inventor)

    1993-01-01

    An alkali metal, such as lithium, is the anodic reactant; carbon dioxide or a mixture of carbon dioxide and carbon monoxide is the cathodic reactant; and carbonate of the alkali metal is the electrolyte in an electrochemical cell for the storage and delivery of electrical energy. Additionally, alkali metal-carbon dioxide battery systems include a plurality of such electrochemical cells. Gold is a preferred catalyst for reducing the carbon dioxide at the cathode. The fuel cell of the invention produces electrochemical energy through the use of an anodic reactant which is extremely energetic and light, and a cathodic reactant which can be extracted from its environment and therefore exacts no transportation penalty. The invention is, therefore, especially useful in extraterrestrial environments.

  6. Biomedical implications of heavy metals induced imbalances in redox systems.

    PubMed

    Sharma, Bechan; Singh, Shweta; Siddiqi, Nikhat J

    2014-01-01

    Several workers have extensively worked out the metal induced toxicity and have reported the toxic and carcinogenic effects of metals in human and animals. It is well known that these metals play a crucial role in facilitating normal biological functions of cells as well. One of the major mechanisms associated with heavy metal toxicity has been attributed to generation of reactive oxygen and nitrogen species, which develops imbalance between the prooxidant elements and the antioxidants (reducing elements) in the body. In this process, a shift to the former is termed as oxidative stress. The oxidative stress mediated toxicity of heavy metals involves damage primarily to liver (hepatotoxicity), central nervous system (neurotoxicity), DNA (genotoxicity), and kidney (nephrotoxicity) in animals and humans. Heavy metals are reported to impact signaling cascade and associated factors leading to apoptosis. The present review illustrates an account of the current knowledge about the effects of heavy metals (mainly arsenic, lead, mercury, and cadmium) induced oxidative stress as well as the possible remedies of metal(s) toxicity through natural/synthetic antioxidants, which may render their effects by reducing the concentration of toxic metal(s). This paper primarily concerns the clinicopathological and biomedical implications of heavy metals induced oxidative stress and their toxicity management in mammals.

  7. Biomedical Implications of Heavy Metals Induced Imbalances in Redox Systems

    PubMed Central

    Singh, Shweta; Siddiqi, Nikhat J.

    2014-01-01

    Several workers have extensively worked out the metal induced toxicity and have reported the toxic and carcinogenic effects of metals in human and animals. It is well known that these metals play a crucial role in facilitating normal biological functions of cells as well. One of the major mechanisms associated with heavy metal toxicity has been attributed to generation of reactive oxygen and nitrogen species, which develops imbalance between the prooxidant elements and the antioxidants (reducing elements) in the body. In this process, a shift to the former is termed as oxidative stress. The oxidative stress mediated toxicity of heavy metals involves damage primarily to liver (hepatotoxicity), central nervous system (neurotoxicity), DNA (genotoxicity), and kidney (nephrotoxicity) in animals and humans. Heavy metals are reported to impact signaling cascade and associated factors leading to apoptosis. The present review illustrates an account of the current knowledge about the effects of heavy metals (mainly arsenic, lead, mercury, and cadmium) induced oxidative stress as well as the possible remedies of metal(s) toxicity through natural/synthetic antioxidants, which may render their effects by reducing the concentration of toxic metal(s). This paper primarily concerns the clinicopathological and biomedical implications of heavy metals induced oxidative stress and their toxicity management in mammals. PMID:25184144

  8. Cell surface engineering of microorganisms towards adsorption of heavy metals.

    PubMed

    Li, Peng-Song; Tao, Hu-Chun

    2015-06-01

    Heavy metal contamination has become a worldwide environmental concern due to its toxicity, non-degradability and food-chain bioaccumulation. Conventional physical and chemical treatment methods for heavy metal removal have disadvantages such as cost-intensiveness, incomplete removal, secondary pollution and the lack of metal specificity. Microbial biomass-based biosorption is one of the approaches gaining increasing attention because it is effective, cheap, and environmental friendly and can work well at low concentrations. To enhance the adsorption properties of microbial cells to heavy metal ions, the cell surface display of various metal-binding proteins/peptides have been performed using a cell surface engineering approach. The surface engineering of Gram-negative bacteria, Gram-positive bacteria and yeast towards the adsorption of heavy metals are reviewed in this article. The problems and future perspectives of this technology are discussed.

  9. Bismuth film electrodes for heavy metals determination

    NASA Astrophysics Data System (ADS)

    Rehacek, Vlastimil; Hotovy, Ivan; Vojs, Marian; Mika, Fedor

    2007-05-01

    Bismuth film electrodes (BiFEs) have a potential to replace toxic mercury used most frequently for determination of heavy metals (Cd, Pb, Zn) by anodic stripping voltammetry. We prepared a graphite disc electrode (0.5 mm in diameter) from a pencil-lead rod and developed a nitrogen doped diamond-like carbon (NDLC) microelectrode array consisting of 50 625 microdiscs with 3 μm in diameter and interelectrode distances of 20 μm on a highly conductive silicon substrate as a support for BiFEs. The disc graphite BiFE was used for simultaneous determination of Pb(II), Cd(II) and Zn(II) by square wave voltammetry (SWV) in an aqueous solution. We found the optimum bismuth-to-metal concentration ratio in the solution to be 20. The dependence of the stripping responses on the concentration of target metals was linear in the range from 1×10 -8 to 1.2×10 -7 mol/L. Detection limits 2.4×10 -9 mol/L for Pb(II), 2.9×10 -9 mol/L for Cd(II) and 1.2×10 -8 mol/L for Zn(II) were estimated. A bismuth-plated NDLC microelectrode array was used for Pb(II) determination by differential pulse voltammetry (DPV) in an aqueous solution. We found that the stripping current for bismuth-plated NDLC array was linear in the concentration range of Pb(II) from 2×10 -8 to 1.2×10 -7 mol/L. The detection limit 2.2×10 -8 mol/L was estimated from a calibration plot.

  10. Heavy metal pollution of ambient air in Nagpur City.

    PubMed

    Chaudhari, Pramod R; Gupta, Rakhi; Gajghate, Daulat Ghilagi; Wate, Satish R

    2012-04-01

    Heavy metals released from different sources in urban environment get adsorbed on respirable particulate matter less than 10 μm in size (PM(10)) and are important from public health point of view causing morbidity and mortality. Therefore, the ambient air quality monitoring was carried out to study the temporal and special pattern in the distribution of PM(10) and associated heavy metal content in the atmosphere of Nagpur, Maharashtra State, India during 2001 as well as in 2006. PM(10) fraction was observed to exceed the stipulated standards in both years. It was also observed that minimum range of PM(10) was observed to be increased in 2006 indicating increase in human activity during nighttime also. Six heavy metals were analyzed and were observed to occur in the order Zn > Fe > Pb > Ni > Cd > Cr in 2006, similar to the trend in other metro cities in India. Lead and Nickel were observed to be within the stipulated standards. Poor correlation coefficient (R(2)) between lead and PM(10) indicated that automobile exhaust is not the source of metals to air pollution. Commercial and industrial activity as well as geological composition may be the potential sources of heavy metal pollution. Total load of heavy metals was found to be increased in 2006 with prominent increase in zinc, lead, and nickel in the environment. Public health impacts of heavy metals as well as certain preventive measures to mitigate the impact of heavy metals on public health are also summarized.

  11. Contamination, toxicity and speciation of heavy metals in an industrialized urban river: Implications for the dispersal of heavy metals.

    PubMed

    Wu, Qihang; Zhou, Haichao; Tam, Nora F Y; Tian, Yu; Tan, Yang; Zhou, Song; Li, Qing; Chen, Yongheng; Leung, Jonathan Y S

    2016-03-15

    Urban rivers are often utilized by the local residents as water source, but they can be polluted by heavy metals due to industrialization. Here, the concentrations, toxicity, speciation and vertical profiles of heavy metals in sediment were examined to evaluate their impact, dispersal and temporal variation in Dongbao River. Results showed that the sediment in the industrialized areas was seriously contaminated with Cr, Cu and Ni which posed acute toxicity. Heavy metals, except Cr and Pb, were mainly associated with non-residual fractions, indicating their high mobility and bioavailability. The non-industrialized areas were also seriously contaminated, suggesting the dispersal of heavy metals along the river. The surface sediment could be more contaminated than the deep sediment, indicating the recent pollution events. Overall, when the point sources are not properly regulated, intense industrialization can cause both serious contamination and dispersal of heavy metals, which have far-reaching consequences in public health and environment.

  12. Metal-mediated aminocatalysis provides mild conditions: Enantioselective Michael addition mediated by primary amino catalysts and alkali-metal ions.

    PubMed

    Leven, Matthias; Neudörfl, Jörg M; Goldfuss, Bernd

    2013-01-01

    Four catalysts based on new amides of chiral 1,2-diamines and 2-sulfobenzoic acid have been developed. The alkali-metal salts of these betaine-like amides are able to form imines with enones, which are activated by Lewis acid interaction for nucleophilic attack by 4-hydroxycoumarin. The addition of 4-hydroxycoumarin to enones gives ee's up to 83% and almost quantitative yields in many cases. This novel type of catalysis provides an effective alternative to conventional primary amino catalysis were strong acid additives are essential components.

  13. Metal-mediated aminocatalysis provides mild conditions: Enantioselective Michael addition mediated by primary amino catalysts and alkali-metal ions

    PubMed Central

    Leven, Matthias; Neudörfl, Jörg M

    2013-01-01

    Summary Four catalysts based on new amides of chiral 1,2-diamines and 2-sulfobenzoic acid have been developed. The alkali-metal salts of these betaine-like amides are able to form imines with enones, which are activated by Lewis acid interaction for nucleophilic attack by 4-hydroxycoumarin. The addition of 4-hydroxycoumarin to enones gives ee’s up to 83% and almost quantitative yields in many cases. This novel type of catalysis provides an effective alternative to conventional primary amino catalysis were strong acid additives are essential components. PMID:23400419

  14. Lanthanoid/Alkali Metal β-Triketonate Assemblies: A Robust Platform for Efficient NIR Emitters.

    PubMed

    Reid, Brodie L; Stagni, Stefano; Malicka, Joanna M; Cocchi, Massimo; Sobolev, Alexandre N; Skelton, Brian W; Moore, Evan G; Hanan, Garry S; Ogden, Mark I; Massi, Massimiliano

    2015-12-07

    The reaction of hydrated lanthanoid chlorides with tribenzoylmethane and an alkali metal hydroxide consistently resulted in the crystallization of neutral tetranuclear assemblies with the general formula [Ln(Ae⋅HOEt)(L)4 ]2 (Ln=Eu(3+) , Er(3+) , Yb(3+) ; Ae=Na(+) , K(+) , Rb(+) ). Analysis of the crystal structures of these species revealed a coordination geometry that varied from a slightly distorted square antiprism to a slightly distorted triangular dodecahedron, with the specific geometrical shape being dependent on the degree of lattice solvation and identity of the alkali metal. The near-infrared (NIR)-emitting assemblies of Yb(3+) and Er(3+) showed remarkably efficient emission, characterized by significantly longer excited-state lifetimes (τobs ≈37-47 μs for Yb(3+) and τobs ≈4-6 μs for Er(3+) ) when compared with the broader family of lanthanoid β-diketonate species, even in the case of perfluorination of the ligands. The Eu(3+) assemblies show bright red emission and a luminescence performance (τobs ≈0.5 ms, ${{\\Phi}{{{\\rm L}\\hfill \\atop {\\rm Ln}\\hfill}}}$≈35-37 %, ηsens ≈68-70 %) more akin to the β-diketonate species. The results highlight that the β-triketonate ligand offers a tunable and facile system for the preparation of efficient NIR emitters without the need for more complicated perfluorination or deuteration synthetic strategies.

  15. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan. Revision 1

    SciTech Connect

    1992-11-01

    The Hanford Site, located northwest of the city of Richland, Washington, houses reactors, chemical-separation systems, and related facilities used for the production of special nuclear materials, as well as for activities associated with nuclear energy development. The 300 Area of the Hanford Site contains reactor fuel manufacturing facilities and several research and development laboratories. The 3718-F Alkali Metal Treatment and Storage Facility (3718-F Facility), located in the 300 Area, was used to store and treat alkali metal wastes. Therefore, it is subject to the regulatory requirements for the storage and treatment of dangerous wastes. Closure will be conducted pursuant to the requirements of the Washington Administrative Code (WAC) 173-303-610 (Ecology 1989) and 40 CFR 270.1. Closure also will satisfy the thermal treatment facility closure requirements of 40 CFR 265.381. This closure plan presents a description of the 3718-F Facility, the history of wastes managed, and the approach that will be followed to close the facility. Only hazardous constituents derived from 3718-F Facility operations will be addressed.

  16. Tungstate-ferrates of some alkali and alkaline-earth metals

    SciTech Connect

    Gruba, A.I.; Danileiko, L.A.; Moroz, Ya.A.; Zyats, M.N.

    1988-02-01

    Tungstate-ferrates of some alkali and alkaline-earth metals with the ratio Fe:W = 2:11, the iron ions in which are found in two types of coordination, tetrahedral and octahedral, were synthesized. The similarity of the IR spectra of the compounds obtained and known compounds with the anion structure of the Keggin type with the composition M/sub X/(XZW/sub 11/O/sub 40/H/sub m/) x nH/sub 2/O indicates that their heteropolyanions are isostructural. The thermal stability of the compounds studied and the structure of the products of thermolysis depend on the charge and radius of the extrasphere cation. When the ratio of the radii of the extrasphere cation of the alkali or alkaline-earth metal to the radius of the ion of the central 3d element, appearing in the coordination sphere of the heteropolytungstates, exceeds 1.6, the most likely products of thermolysis of heteropolycompounds are the compounds of the pyrochlore family and tungsten bronzes.

  17. Higher-order C{sub n} dispersion coefficients for the alkali-metal atoms

    SciTech Connect

    Mitroy, J.; Bromley, M.W.J.

    2005-04-01

    The van der Waals coefficients, from C{sub 11} through to C{sub 16} resulting from second-, third-, and fourth-order perturbation theory are estimated for the alkali-metal (Li, Na, K, and Rb) atoms. The dispersion coefficients are also computed for all possible combinations of the alkali-metal atoms and hydrogen. The parameters are determined from sum rules after diagonalizing a semiempirical fixed core Hamiltonian in a large basis. Comparisons of the radial dependence of the C{sub n}/r{sup n} potentials give guidance as to the radial regions in which the various higher-order terms can be neglected. It is seen that including terms up to C{sub 10}/r{sup 10} results in a dispersion interaction that is accurate to better than 1% whenever the inter-nuclear spacing is larger than 20a{sub 0}. This level of accuracy is mainly achieved due to the fortuitous cancellation between the repulsive (C{sub 11},C{sub 13},C{sub 15}) and attractive (C{sub 12},C{sub 14},C{sub 16}) dispersion forces.

  18. Matrix diffusion of some alkali- and alkaline earth-metals in granitic rock

    SciTech Connect

    Johansson, H.; Byegaard, J.; Skarnemark, G.; Skaalberg, M.

    1997-12-31

    Static through-diffusion experiments were performed to study the diffusion of alkali- and alkaline earth-metals in fine-grained granite and medium-grained Aespoe-diorite. Tritiated water was used as an inert reference tracer. Radionuclides of the alkali- and alkaline earth-metals (mono- and divalent elements which are not influenced by hydrolysis in the pH-range studied) were used as tracers, i.e., {sup 22}Na{sup +}, {sup 45}Ca{sup 2+} and {sup 85}Sr{sup 2+}. The effective diffusivity and the rock capacity factor were calculated by fitting the breakthrough curve to the one-dimensional solution of the diffusion equation. Sorption coefficients, K{sub d}, that were derived from the rock capacity factor (diffusion experiments) were compared with K{sub d} determined in batch experiments using crushed material of different size fractions. The results show that the tracers were retarded in the same order as was expected from the measured batch K{sub d}. Furthermore, the largest size fraction was the most representative when comparing batch K{sub d} with K{sub d} evaluated from the diffusion experiments. The observed effective diffusivities tended to decrease with increasing cell lengths, indicating that the transport porosity decreases with increasing sample lengths used in the diffusion experiments.

  19. Alkali Metal Control over N–N Cleavage in Iron Complexes

    PubMed Central

    2015-01-01

    Though N2 cleavage on K-promoted Fe surfaces is important in the large-scale Haber–Bosch process, there is still ambiguity about the number of Fe atoms involved during the N–N cleaving step and the interactions responsible for the promoting ability of K. This work explores a molecular Fe system for N2 reduction, particularly focusing on the differences in the results obtained using different alkali metals as reductants (Na, K, Rb, Cs). The products of these reactions feature new types of Fe–N2 and Fe-nitride cores. Surprisingly, adding more equivalents of reductant to the system gives a product in which the N–N bond is not cleaved, indicating that the reducing power is not the most important factor that determines the extent of N2 activation. On the other hand, the results suggest that the size of the alkali metal cation can control the number of Fe atoms that can approach N2, which in turn controls the ability to achieve N2 cleavage. The accumulated results indicate that cleaving the triple N–N bond to nitrides is facilitated by simultaneous approach of least three low-valent Fe atoms to a single molecule of N2. PMID:25412468

  20. Optical methods for the detection of heavy metal ions

    NASA Astrophysics Data System (ADS)

    Uglov, A. N.; Bessmertnykh-Lemeune, A.; Guilard, R.; Averin, A. D.; Beletskaya, I. P.

    2014-03-01

    The review covers an important area of the modern chemistry, namely, the detection of heavy metal ions using optical molecular detectors. The role of this method in metal ion detection and the physicochemical grounds of operation of chemosensors are discussed, and examples of detection of most abundant heavy metal ions and synthetic approaches to molecular detectors are presented. The immobilization of molecular detectors on solid substrates for the design of analytical sensor devices is described. The bibliography includes 178 references.

  1. Challenges and Prospect of Non-aqueous Non-alkali (NANA) Metal-Air Batteries.

    PubMed

    Gelman, Danny; Shvartsev, Boris; Ein-Eli, Yair

    2016-12-01

    Non-aqueous non-alkali (NANA) metal-air battery technologies promise to provide electrochemical energy storage with the highest specific energy density. Metal-air battery technology is particularly advantageous being implemented in long-range electric vehicles. Up to now, almost all the efforts in the field are focused on Li-air cells, but other NANA metal-air battery technologies emerge. The major concern, which the research community should be dealing with, is the limited and rather poor rechargeability of these systems. The challenges we are covering in this review are related to the initial limited discharge capacities and cell performances. By comprehensively reviewing the studies conducted so far, we show that the implementation of advanced materials is a promising approach to increase metal-air performance and, particularly, metal surface activation as a prime achievement leading to respectful discharge currents. In this review, we address the most critical areas that need careful research attention in order to achieve progress in the understanding of the physical and electrochemical processes in non-aqueous electrolytes applied in beyond lithium and zinc air generation of metal-air battery systems.

  2. [Application of ICP-MS to determination of heavy metal content of heavy metals in two kinds of N fertilizer].

    PubMed

    Rui, Yu-kui; Shen, Jian-bo; Zhang, Fu-suo

    2008-10-01

    Environmental safety has been the focus worldwide, where involved are the pollutions of heavy metals, pesticides and persistent organic pollutants. Fertilizer has become one of the polluting sources of heavy metals, which are very deleterious to human health and environmental safety. Heavy metals are difficult to metabolize in human body and very harmful, so research on the pollution of heavy metals is considered increasingly important. The pollution sources of heavy metals include waste residue, waste water and exhaust gas from industry and automobile, and garbage from human life. The heavy metals in fertilizer can endanger the human body by the crop containing heavy metals. Two kinds of nitrogen fertilizer were analyzed in terms of the content of heavy metals by ICP-MS, and the results showed that the content of 10 kinds of heavy metals (Al, Ti, Cr, Ni, Cu, Zn, As, Cd, Hg and Pb) in (NH4)2SO4 was 1345.13, 35.12, 2539.27, 287.26, 674.05, 270.79, 42.54, 22.13, 27.20 and 123.87 ng x g(-1) respectively; and in CO(NH2)2 it is 71.59, 5.36, 1167.71, 188.60, 7.46, 64.45, 10.55, 0.00, 0.09 and 3.71 ng x g(-1) respectively. All the data showed that CO(NH2)2 contained much less heavy metals than (NH4)2SO4, so we should select CO(NH2)2 as the nitrogen fertilizer in agricultural production.

  3. Resonance line broadening of alkali metals in pyrotechnic flames. Doctoral thesis

    SciTech Connect

    Dillehay, D.R.

    1983-04-15

    A mathematical model of a pyrotechnic flame has been developed and validated. The model utilizes a computer program to calculate the relative radiant power of flares containing any of the alkali metals. The computation takes into consideration known system variables such as formulation, candle size, displacement along the plume axis, and atmospheric pressure. These effects were evaluated over a wide range of conditions and the computed spectra follow the established experimental spectra trends. The computer solution is a general solution requiring no ad hoc modifications to the model for any of the metals or conditions tested. The basis for the model of the flame permits calculation of the effects of mixing of the flare plume with the ambient atmosphere and takes heat loss along the plume axis into consideration.

  4. The intrinsic stabilities and structures of alkali metal cationized guanine quadruplexes.

    PubMed

    Azargun, M; Jami-Alahmadi, Y; Fridgen, T D

    2017-01-04

    The structures and stabilities of self-assembled guanine quadruplexes, M(9eG)8(+) (M = Na, K, Rb, Cs; 9eG = 9-ethylguanine), have been studied in the gas phase by blackbody infrared radiative dissociation to determine the difference in the stabilizing effect of the alkali metal cations. The order of stabilities to decomposition was determined to be K(+) > Rb(+) > Cs(+) ≫ Na(+), which is consistent with the observation of K(+) being the ion of choice in guanine quadruplexes in nucleic acids. In the gas phase, the sodiated quadruplex was found to lose one 9eG at a time, whereas the quadruplexes of the heavier cations lost a neutral guanine tetrad. Vibrational spectroscopy on the gas-phase quadruplex ions was consistent with the structures in which the metal cations were sandwiched between two guanine tetrads. Electronic structure calculations are also used to compare with the observed stabilities and vibrational spectra.

  5. First hyperpolarizability of cyclooctatetraene modulated by alkali and alkaline earth metals.

    PubMed

    Roy, Ria Sinha; Mondal, Avijit; Nandi, Prasanta K

    2017-03-01

    In the present investigation, the first hyperpolarizability of alkali and alkaline earth metal derivatives of cyclooctatetraene (COT) has been calculated using BHHLYP and CAM-B3LYP functional for 6-311++G(d,p), 6-311++G(3df,3pd), and aug-pc 2 basis sets. Introduction of Na/K atoms at the axial position of COT and Li, Na, K/Be, Mg, Ca metal atoms and cyanide groups at the equatorial sites leads to lager enhancement of first hyperpolarizability. The ring charge density can account for the variation of first hyperpolarizability. The two state model has been invoked to explain the variation of first hyperpolarizability.

  6. Heavy metal displacement in chelate-irrigated soil during phytoremediation

    NASA Astrophysics Data System (ADS)

    Madrid, F.; Liphadzi, M. S.; Kirkham, M. B.

    2003-03-01

    Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with and without roots following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals in biosolids applied to the surface of soil columns (76 cm long; 17 cm diam.) with or without plants (barley; Hordeum vulgare L.). Three weeks after barley was planted, all columns were irrigated with the disodium salt of the chelating agent, EDTA (ethylenediamine tetraacetic acid) (0.5 g/kg soil). Drainage water, soil, and plants were analyzed for heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, Zn). Total concentrations of the heavy metals in all columns at the end of the experiment generally were lower in the top 30 cm of soil with EDTA than without EDTA. The chelate increased concentrations of heavy metals in shoots. With or without plants, the EDTA mobilized Cd, Fe, Mn, Ni, Pb, and Zn, which leached to drainage water. Drainage water from columns without EDTA had concentrations of these heavy metals below detection limits. Only Cu did not leach in the presence of EDTA. Even though roots retarded the movement of Cd, Fe, Mn, Ni, Pb, and Zn through the EDTA-treated soil from 1 d (Cd) to 5 d (Fe), the drainage water from columns with EDTA had concentrations of Cd, Fe, Mn, and Pb that exceeded drinking water standards by 1.3, 500, 620, and 8.6 times, respectively. Because the chelate rendered Cd, Fe, Mn, Ni, Pb, and Zn mobile, it is suggested that the theory for leaching of soluble salts, put forward by Nielsen and associates in 1965, could be applied to control movement of the heavy metals for maximum uptake during chelate-assisted phytoremediation.

  7. The contents of alkali and alkaline earth metals in soils of the southern Cis-Ural region

    NASA Astrophysics Data System (ADS)

    Asylbaev, I. G.; Khabirov, I. K.

    2016-01-01

    The contents and distribution patterns of alkali and alkaline earth metals in soils and rocks of the southern Cis-Ural region were studied. A database on the contents of these metals was developed, the soils were classified with respect to their provision with these metals, and corresponding schematic maps showing their distribution in soils of the region were compiled. It was found that the contents of these metals decrease from east to west (from the Yuryuzan-Aisk Piedmont Plain to the Ufa Plateau and to the Belebeevsk Upland), and their distribution patterns change. Among alkali metals, the highest accumulation in the soils is typical of potassium, sodium, and cesium; among alkaline earth metals, of strontium and barium.

  8. Theoretical analysis of oxygen diffusion at startup in an alkali metal heat pipe with gettered alloy walls

    NASA Technical Reports Server (NTRS)

    Tower, L. K.

    1973-01-01

    The diffusion of oxygen into, or out of, a gettered alloy exposed to oxygenated alkali liquid metal coolant, a situation arising in some high temperature heat transfer systems, was analyzed. The relation between the diffusion process and the thermochemistry of oxygen in the alloy and in the alkali metal was developed by making several simplifying assumptions. The treatment is therefore theoretical in nature. However, a practical example pertaining to the startup of a heat pipe with walls of T-111, a tantalum alloy, and lithium working fluid illustrates the use of the figures contained in the analysis.

  9. Ab initio interaction potentials and scattering lengths for ultracold mixtures of metastable helium and alkali-metal atoms

    NASA Astrophysics Data System (ADS)

    Kedziera, Dariusz; Mentel, Łukasz; Żuchowski, Piotr S.; Knoop, Steven

    2015-06-01

    We have obtained accurate ab initio +4Σ quartet potentials for the diatomic metastable triplet helium+alkali-metal (Li, Na, K, Rb) systems, using all-electron restricted open-shell coupled cluster singles and doubles with noniterative triples corrections CCSD(T) calculations and accurate calculations of the long-range C6 coefficients. These potentials provide accurate ab initio quartet scattering lengths, which for these many-electron systems is possible, because of the small reduced masses and shallow potentials that result in a small amount of bound states. Our results are relevant for ultracold metastable triplet helium+alkali-metal mixture experiments.

  10. Alkali metal cation binding affinities of cytosine in the gas phase: revisited.

    PubMed

    Yang, Bo; Rodgers, M T

    2014-08-14

    Binding of metal cations to the nucleobases can influence base pairing, base stacking and nucleobase tautomerism. Gas-phase condensation of dc discharge generated alkali metal cations and thermally vaporized cytosine (DC/FT) has been found to produce kinetically trapped excited tautomeric conformations of the M(+)(cytosine) complexes, which influences the threshold collision-induced dissociation (TCID) behavior. In order to elucidate the effects of the size of alkali metal cation on the strength of binding to the canonical form of cytosine, the binding affinities of Na(+) and K(+) to cytosine are re-examined here, and studies are extended to include Rb(+) and Cs(+) again using TCID techniques. The M(+)(cytosine) complexes are generated in an electrospray ionization source, which has been shown to produce ground-state tautomeric conformations of M(+)(cytosine). The energy-dependent cross sections are interpreted to yield bond dissociation energies (BDEs) using an analysis that includes consideration of unimolecular decay rates, the kinetic and internal energy distributions of the reactants, and multiple M(+)(cytosine)-Xe collisions. Revised BDEs for the Na(+)(cytosine) and K(+)(cytosine) complexes exceed those previously measured by 31.9 and 25.5 kJ mol(-1), respectively, consistent with the hypothesis proposed by Yang and Rodgers that excited tautomeric conformations are accessed when the complexes are generated by DC/FT ionization. Experimentally measured BDEs are compared to theoretical values calculated at the B3LYP and MP2(full) levels of theory using the 6-311+G(2d,2p)_HW* and def2-TZVPPD basis sets. The B3LYP/def2-TZVPPD level of theory is found to provide the best agreement with the measured BDEs, suggesting that this level of theory can be employed to provide reliable energetics for similar metal-ligand systems.

  11. Heavy metal-induced glutathione accumulation and its role in heavy metal detoxification in Phanerochaete chrysosporium.

    PubMed

    Xu, Piao; Liu, Liang; Zeng, Guangming; Huang, Danlian; Lai, Cui; Zhao, Meihua; Huang, Chao; Li, Ningjie; Wei, Zhen; Wu, Haipeng; Zhang, Chen; Lai, Mingyong; He, Yibin

    2014-01-01

    Phanerochaete chrysosporium are known to be vital hyperaccumulation species for heavy metal removal with admirable intracellular bioaccumulation capacity. This study analyzes the heavy metal-induced glutathione (GSH) accumulation and the regulation at the intracellular heavy metal level in P. chrysosporium. P. chrysosporium accumulated high levels of GSH, accompanied with high intracellular concentrations of Pb and Cd. Pb bioaccumulation lead to a narrow range of fluctuation in GSH accumulation (0.72-0.84 μmol), while GSH plummeted under Cd exposure at the maximum value of 0.37 μmol. Good correlations between time-course GSH depletion and Cd bioaccumulation were determined (R (2) > 0.87), while no significant correlations have been found between GSH variation and Pb bioaccumulation (R (2) < 0.38). Significantly, concentration-dependent molar ratios of Pb/GSH ranging from 0.10 to 0.18 were observed, while molar ratios of Cd/GSH were at the scope of 1.53-3.32, confirming the dominant role of GSH in Cd chelation. The study also demonstrated that P. chrysosporium showed considerable hypertolerance to Pb ions, accompanied with demand-driven stimulation in GSH synthesis and unconspicuous generation of reactive oxygen stress. GSH plummeted dramatically response to Cd exposure, due to the strong affinity of GSH to Cd and the involvement of GSH in Cd detoxification mechanism mainly as Cd chelators. Investigations into GSH metabolism and its role in ameliorating metal toxicity can offer important information on the application of the microorganism for wastewater treatment.

  12. Leaching Properties of Naturally Occurring Heavy Metals from Soils

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Hoshino, M.; Yoshikawa, M.; Hara, J.; Sugita, H.

    2014-12-01

    The major threats to human health from heavy metals are associated with exposure to arsenic, lead, cadmium, chromium, mercury, as well as some other elements. The effects of such heavy metals on human health have been extensively studied and reviewed by international organizations such as WHO. Due to their toxicity, heavy metal contaminations have been regulated by national environmental standards in many countries, and/or laws such as the Soil Contamination Countermeasures Act in Japan. Leaching of naturally occurring heavy metals from the soils, especially those around abandoned metal mines into surrounding water systems, either groundwater or surface water systems, is one of the major pathways of exposure. Therefore, understanding the leaching properties of toxic heavy metals from naturally polluted soils is of fundamentally importance for effectively managing abandoned metal mines, excavated rocks discharged from infrastructure constructions such as tunneling, and/or selecting a pertinent countermeasure against pollution when it is necessary. In this study, soil samples taken from the surroundings of abandoned metal mines in different regions in Japan were collected and analyzed. The samples contained multiple heavy metals such as lead, arsenic and chromium. Standard leaching test and sequential leaching test considering different forms of contaminants, such as trivalent and pentavalent arsenics, and trivalent and hexavalent chromiums, together with standard test for evaluating total concentration, X-ray Fluorescence Analysis (XRF), X-ray diffraction analysis (XRD) and Cation Exchange Capacity (CEC) tests were performed. In addition, sequential leaching tests were performed to evaluate long-term leaching properties of lead from representative samples. This presentation introduces the details of the above experimental study, discusses the relationships among leaching properties and chemical and mineral compositions, indicates the difficulties associated with

  13. Microalgae - A promising tool for heavy metal remediation.

    PubMed

    Suresh Kumar, K; Dahms, Hans-Uwe; Won, Eun-Ji; Lee, Jae-Seong; Shin, Kyung-Hoon

    2015-03-01

    Biotechnology of microalgae has gained popularity due to the growing need for novel environmental technologies and the development of innovative mass-production. Inexpensive growth requirements (solar light and CO2), and, the advantage of being utilized simultaneously for multiple technologies (e.g. carbon mitigation, biofuel production, and bioremediation) make microalgae suitable candidates for several ecofriendly technologies. Microalgae have developed an extensive spectrum of mechanisms (extracellular and intracellular) to cope with heavy metal toxicity. Their wide-spread occurrence along with their ability to grow and concentrate heavy metals, ascertains their suitability in practical applications of waste-water bioremediation. Heavy metal uptake by microalgae is affirmed to be superior to the prevalent physicochemical processes employed in the removal of toxic heavy metals. In order to evaluate their potential and to fill in the loopholes, it is essential to carry out a critical assessment of the existing microalgal technologies, and realize the need for development of commercially viable technologies involving strategic multidisciplinary approaches. This review summarizes several areas of heavy metal remediation from a microalgal perspective and provides an overview of various practical avenues of this technology. It particularly details heavy metals and microalgae which have been extensively studied, and provides a schematic representation of the mechanisms of heavy metal remediation in microalgae.

  14. Toxicity of heavy metals and metal-containing nanoparticles on plants.

    PubMed

    Mustafa, Ghazala; Komatsu, Setsuko

    2016-08-01

    Plants are under the continual threat of changing climatic conditions that are associated with various types of abiotic stresses. In particular, heavy metal contamination is a major environmental concern that restricts plant growth. Plants absorb heavy metals along with essential elements from the soil and have evolved different strategies to cope with the accumulation of heavy metals. The use of proteomic techniques is an effective approach to investigate and identify the biological mechanisms and pathways affected by heavy metals and metal-containing nanoparticles. The present review focuses on recent advances and summarizes the results from proteomic studies aimed at understanding the response mechanisms of plants under heavy metal and metal-containing nanoparticle stress. Transport of heavy metal ions is regulated through the cell wall and plasma membrane and then sequestered in the vacuole. In addition, the role of different metal chelators involved in the detoxification and sequestration of heavy metals is critically reviewed, and changes in protein profiles of plants exposed to metal-containing nanoparticles are discussed in detail. Finally, strategies for gaining new insights into plant tolerance mechanisms to heavy metal and metal-containing nanoparticle stress are presented. This article is part of a Special Issue entitled: Plant Proteomics--a bridge between fundamental processes and crop production, edited by Dr. Hans-Peter Mock.

  15. Improving crop tolerance to heavy metal stress by polyamine application.

    PubMed

    Soudek, Petr; Ursu, Marina; Petrová, Šárka; Vaněk, Tomáš

    2016-12-15

    Many areas have been heavily contaminated by heavy metals from industry and are not suitable for food production. The consumption of contaminated foods represents a health risk in humans, although some heavy metals are essential at low concentrations. Increasing the concentrations of essential elements in foods is one goal to improve nutrition. The aim of this study was to increase the accumulation of heavy metals in plant foods by the external application of putrescine. The levels of cadmium, zinc and iron were measured in different vegetables grown in hydroponic medium supplemented with heavy metals and compared with those grown in a reference medium. The estimated daily intake, based on the average daily consumption for various vegetable types, and the influence of polyamines on metal uptake were calculated.

  16. Heavy metal music and adolescent suicidality: an empirical investigation.

    PubMed

    Scheel, K R; Westefeld, J S

    1999-01-01

    This study investigated the relationship between preference for heavy metal music and vulnerability to suicide among 121 high school students. Heavy metal fans had less strong reasons for living (especially male fans) and had more thoughts of suicide (especially female fans). For a large majority, listening to music (all types) had a positive effect on mood. Overall, the results indicate that preference for heavy metal music among adolescents may be a "red flag" for increased suicidal vulnerability, but also suggest that the source of the problem may lie more in personal and familial characteristics than in any direct effects of the music. Implications for intervention and for future research are discussed.

  17. Adsorption behavior of heavy metals on biomaterials.

    PubMed

    Minamisawa, Mayumi; Minamisawa, Hiroaki; Yoshida, Shoichiro; Takai, Nobuharu

    2004-09-08

    We have investigated adsorption of Cd(II) and Pb(II) at pH 2-6.7 onto the biomaterials chitosan, coffee, green tea, tea, yuzu, aloe, and Japanese coarse tea, and onto the inorganic adsorbents, activated carbon and zeolite. High adsorptive capabilities were observed for all of the biomaterials at pH 4 and 6.7. In the adsorption of Cd(II), blend coffee, tea, green tea, and coarse tea have comparable loading capacities to activated carbon and zeolite. Although activated carbon, zeolite, and chitosan are utilized in a variety of fields such as wastewater treatment, chemical and metallurgical engineering, and analytical chemistry, these adsorbents are costly. On the other hand, processing of the test biomaterials was inexpensive, and all the biomaterials except for chitosan were able to adsorb large amounts of Pb(II) and Cd(II) ions after a convenient pretreatment of washing with water followed by drying. The high adsorption capability of the biomaterials prepared from plant materials is promising in the development of a novel, low-cost adsorbent. From these results, it is concluded that heavy metal removal using biomaterials would be an effective method for the economic treatment of wastewater. The proposed adsorption method was applied to the determination of amounts of Cd(II) and Pb(II) in water samples.

  18. Triuret as a Potential Hypokalemic Agent: Structure Characterization of Triuret and Triuret-Alkali Metal Adducts by Mass Spectrometric Techniques

    PubMed Central

    Palii, Sergiu P.; Contreras, Cesar S.; Steill, Jeffrey D.; Palii, Stela S.; Oomens, Jos; Eyler, John R.

    2013-01-01

    Triuret (also known as carbonyldiurea, dicarbamylurea, or 2,4-diimidotricarbonic diamide) is a byproduct of purine degradation in living organisms. An abundant triuret precursor is uric acid, whose level is altered in multiple metabolic pathologies. Triuret can be generated via urate oxidation by peroxynitrite, the latter being produced by the reaction of nitric oxide radical with superoxide radical anion. From this standpoint, an excess production of superoxide radical anions could indirectly favor triuret formation; however very little is known about the potential in vivo roles of this metabolite. Triuret’s structure is suggestive of its ability to adopt various conformations and act as a flexible ligand for metal ions. In the current study, HPLC-MS/MS, energy-resolved mass spectrometry, selected ion monitoring, collision-induced dissociation, IRMPD spectroscopy, Fourier transform-ion cyclotron resonance mass spectrometry and computational methods were employed to characterize the structure of triuret and its metal complexes, to determine the triuret-alkali metal binding motif, and to evaluate triuret affinity toward alkali metal ions, as well as its affinity for Na+ and K+ relative to other organic ligands. The most favored binding motif was determined to be a bidentate chelation of triuret with the alkali metal cation involving two carbonyl oxygens. Using the complexation selectivity method, it was observed that in solution triuret has an increased affinity for potassium ions, compared to sodium and other alkali metal ions. We propose that triuret may act as a potential hypokalemic agent under pathophysiological conditions conducive to its excessive formation and thus contribute to electrolyte disorders. The collision- or photo-induced fragmentation channels of deprotonated and protonated triuret, as well as its alkali metal adducts, are likely to mimic the triuret degradation pathways in vivo. PMID:20371222

  19. Alkali metal vapor removal from pressurized fluidized-bed combustor flue gas. Quarterly report, April-June 1980

    SciTech Connect

    Johnson, I.; Swift, W.M.; Lee, S.H.D.; Boyd, W.A.

    1980-07-01

    In the application of pressurized fluidized-bed combustors (PFBC) to the generation of electricity, hot corrosion of gas turbine components by alkali metal compounds is a potential problem. The objective of this investigation is to develop a method for removing these gaseous alkali metal compounds from the high-pressure high-temperature gas from a PFBC before the gas enters the gas turbine. A granular-bed filter, using either diatomaceous earth or activated bauxite as the bed material, is the concept currently being studied. Results are presented for the testing of diatomaceous earth for alkali vapor sorption at 800/sup 0/C and 9-atm pressure, using a simulated flue gas. Activated bauxite sorbent can be regenerated by leaching with water, and the kinetics of the leaching is under study.

  20. Mixed ionic and electronic conducting electrode studies for an alkali metal thermal to electric converter

    NASA Astrophysics Data System (ADS)

    Guo, Yuyan

    This research focuses on preparation, kinetics, and performance studies of mixed ionic and electronic conducting electrodes (MIEE) applied in an alkali metal thermal to electric converter (AMTEC). Two types of MIEE, metal/sodium titanate and metal/beta″-alumina were investigated, using Ni, Cu, Co and W as the metal components. Pure metal electrodes (PME) were also studied, including Ta, Ni, Nb, Ir, W and MoRe electrodes. The stability of MIEE/beta″-alumina solid electrolyte (BASE) interface was studied in terms of the chemical potential of Na-Al-Ti-O system at 1100K (typical AMTEC operating temperature). Ni metal was compatible with sodium titanate and BASE and displayed the best initial performance among all tested PMEs. Ni/sodium titanate electrodes with 4/1 mass ratios of metal/ceramic performed best among all tested electrodes. Scanning Electron Microscope (SEM) observations showed that grain agglomeration, which is the main mechanism for electrode degradation, occurred in all tested electrodes. Ceramic components were able to effectively limit the growth of metal grains and resulted in a long lifetime for MIEEs. Ni particles in the MIEE formed a network microstructure that was close to the theoretical morphology of the ideal electrode. A model based on percolation theory was constructed to interpret and predict the performance of MIEEs. The electrode kinetics was studied and a theoretical expression for the interface impedance was derived for both PME and MIEE, using electrochemical impedance spectroscopy (EIS). The conductivity of the Na2Ti 3O7 and Na2Ti6O13 mixture was measured. The average activation energy for the bulk conductivity was 0.87ev. Finally, theoretical analysis clarified that the transfer coefficient alpha value change would cause at most a few percent change in the electrode performance parameter B.

  1. ION EXCHANGE IN FUSED SALTS. II. THE DISTRIBUTION OF ALKALI METAL AND ALKALINE EARTH IONS BETWEEN CHABAZITE AND FUSED LINO3, NANO3, AND KNO3,

    DTIC Science & Technology

    ION EXCHANGE, SALTS ), (*ALKALI METALS, ION EXCHANGE), (*ALKALINE EARTH METALS, ION EXCHANGE), (*NITRATES, ION EXCHANGE), SODIUM , CALCIUM, POTASSIUM...BARIUM, RUBIDIUM, CESIUM, LITHIUM COMPOUNDS, SODIUM COMPOUNDS, POTASSIUM COMPOUNDS, DISTRIBUTION, MINERALS, IONS

  2. Dispersion coefficients for H and He interactions with alkali-metal and alkaline-earth-metal atoms

    SciTech Connect

    Mitroy, J.; Bromley, M.W.J.

    2003-12-01

    The van der Waals coefficients C{sub 6}, C{sub 8}, and C{sub 10} for H and He interactions with the alkali-metal (Li, Na, K, and Rb) and alkaline-earth-metal (Be, Mg, Ca, and Sr) atoms are determined from oscillator strength sum rules. The oscillator strengths were computed using a combination of ab initio and semiempirical methods. The dispersion parameters generally agree with close to exact variational calculations for Li-H and Li-He at the 0.1% level of accuracy. For larger systems, there is agreement with relativistic many-body perturbation theory estimates of C{sub 6} at the 1% level. These validations for selected systems attest to the reliability of the present dispersion parameters. About half the present parameters lie within the recommended bounds of the Standard and Certain compilation [J. Chem. Phys. 83, 3002 (1985)].

  3. Investigation of anti-Relaxation coatings for alkali-metal vapor cells using surface science techniques

    SciTech Connect

    Seltzer, S. J.; Michalak, D. J.; Donaldson, M. H.; Balabas, M. V.; Barber, S. K.; Bernasek, S. L.; Bouchiat, M.-A.; Hexemer, A.; Hibberd, A. M.; Jackson Kimball, D. F.; Jaye, C.; Karaulanov, T.; Narducci, F. A.; Rangwala, S. A.; Robinson, H. G.; Shmakov, A. K.; Voronov, D. L.; Yashchuk, V. V.; Pines, A.; Budker, D.

    2010-10-11

    Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of antirelaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10?000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge x-ray absorption fine structure spectroscopy, and x-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of C=C double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin antirelaxation coatings, as well as the design and synthesis of new classes of coating materials.

  4. Emergence of symmetry and chirality in crown ether complexes with alkali metal cations.

    PubMed

    Martínez-Haya, Bruno; Hurtado, Paola; Hortal, Ana R; Hamad, Said; Steill, Jeffrey D; Oomens, Jos

    2010-07-08

    Crown ethers provide a valuable benchmark for the comprehension of molecular recognition mediated by inclusion complexes. One of the most relevant crown ethers, 18-crown-6 (18c6), features a flexible six-oxygen cyclic backbone that is well-known for its selective cation binding. This study employs infrared spectroscopy and quantum mechanical calculations to elucidate the structure of the gas-phase complexes formed by the 18c6 ether with the alkali metal cations. It is shown that symmetric and chiral arrangements play a dominant role in the conformational landscape of the 18c6-alkali system. Most stable 18c6-M(+) conformers are found to have symmetries C(3v) and C(2) for Cs(+), D(3d) for K(+), C(1) and D(3d) for Na(+), and D(2) for Li(+). Remarkably, whereas the bare 18c6 ether is achiral, chirality emerges in the C(2) and D(2) 18c6-M(+) conformations, both of which involve pairs of stable atropoisomers capable of acting as enantiomeric selective substrates.

  5. Silicon halide-alkali metal flames as a source of solar grade silicon

    NASA Technical Reports Server (NTRS)

    Olsen, D. B.; Miller, W. J.

    1979-01-01

    The feasibility of using alkali metal-silicon halide diffusion flames to produce solar-grade silicon in large quantities and at low cost is demonstrated. Prior work shows that these flames are stable and that relatively high purity silicon can be produced using Na + SiCl4 flames. Silicon of similar purity is obtained from Na + SiF4 flames although yields are lower and product separation and collection are less thermochemically favored. Continuous separation of silicon from the byproduct alkali salt was demonstrated in a heated graphite reactor. The process was scaled up to reduce heat losses and to produce larger samples of silicon. Reagent delivery systems, scaled by a factor of 25, were built and operated at a production rate of 0.5 kg Si/h. Very rapid reactor heating rates are observed with wall temperatures reaching greater than 2000 K. Heat release parameters were measured using a cooled stainless steel reactor tube. A new reactor was designed.

  6. Heavy Metals and Epigenetic Alterations in Brain Tumors

    PubMed Central

    Caffo, Maria; Caruso, Gerardo; Fata, Giuseppe La; Barresi, Valeria; Visalli, Maria; Venza, Mario; Venza, Isabella

    2014-01-01

    Heavy metals and their derivatives can cause various diseases. Numerous studies have evaluated the possible link between exposure to heavy metals and various cancers. Recent data show a correlation between heavy metals and aberration of genetic and epigenetic patterns. From a literature search we noticed few experimental and epidemiological studies that evaluate a possible correlation between heavy metals and brain tumors. Gliomas arise due to genetic and epigenetic alterations of glial cells. Changes in gene expression result in the alteration of the cellular division process. Epigenetic alterations in brain tumors include the hypermethylation of CpG group, hypomethylation of specific genes, aberrant activation of genes, and changes in the position of various histones. Heavy metals are capable of generating reactive oxygen assumes that key functions in various pathological mechanisms. Alteration of homeostasis of metals could cause the overproduction of reactive oxygen species and induce DNA damage, lipid peroxidation, and alteration of proteins. In this study we summarize the possible correlation between heavy metals, epigenetic alterations and brain tumors. We report, moreover, the review of relevant literature. PMID:25646073

  7. Estimation of heavy metal transformations in municipal solid waste.

    PubMed

    Flyhammar, P

    1997-05-30

    The behaviour of heavy metals bound to municipal solid waste (MSW) and exposed to 2 decades of anaerobic waste stabilization processes have been estimated. Heavy metal solid forms in a waste degradation residue have been compared with a reconstructed waste similar to that initially disposed of in 1973. The initial waste was composed of a mixture of shredded MSW (95% dry wt.) and anaerobic sewage sludge (5% dry wt.). A sequential chemical extraction method has been used to fractionate the heavy metals into five categories of available and reactive solid forms. The results imply that these forms can be ascribed to approximately 30% of the total content of the heavy metals in the degraded waste and the portion of heavy metals bound to oxidizable solid forms seems to be higher in the degraded than the fresh MSW. The bulk of the remaining heavy metals are assumed to be less available and bound into resistant lattice structures, such as metal and polymer items. A comparison between fractionation patterns of the waste in this study and of a few sediments collected from different environments imply similarities between the fresh MSW and an oxic sediment from one site and the sewage sludge and anoxic sediments from another site. Fractionation patterns of the degraded waste are found to be quite similar to those of the anoxic sediments, except for Pb, Ni and Cd which are more similar to fresh MSW.

  8. Selection of ectomycorrhizal willow genotype in phytoextraction of heavy metals.

    PubMed

    Hrynkiewicz, Katarzyna; Baum, Christel

    2013-01-01

    Willow clones are used for the phytoextraction of heavy metals from contaminated soils and are usually mycorrhizal. The receptiveness of willow clones for mycorrhizal inoculum varies specific to genotype; however, it is unknown if this might have a significant impact on their efficiency in phytoextraction of heavy metals. Therefore, a model system with mycorrhizal and non-mycorrhizal willows of two different genotypes--one with usually stronger natural mycorrhizal colonization (Salix dasyclados), and one with lower natural mycorrhizal colonization (S. viminalis)--was investigated for its efficiency of phytoextraction of heavy metals (Cd, Pb, Cu, Zn) from contaminated soil. Inoculation with the ectomycorrhizal fungus Amanita muscaria significantly decreased the biomass of leaves of both inoculated willow clones, and increased or had no effect on the biomass of trunks and roots of S. dasyclados and S. viminalis, respectively. The concentrations of heavy metals in the biomass of S. dasyclados were in general higher than in S. viminalis irrespective of inoculation with the ectomycorrhizal fungus. Inoculation with A. muscaria significantly decreased the concentration of Cu in the trunks of both Salix taxa, but did not affected the concentrations of other heavy metals in the biomass. In conclusion, stronger receptiveness of willow clones for mycorrhizal inoculum was correlated with an increased total extraction of heavy metals from contaminated soils. Therefore, this seems to be a suitable criterion for effective willow clone selection for phytoremediation. Increased biomass production with relatively constant metal concentrations seems to be a major advantage of mycorrhizal formation of willows in phytoremediation of contaminated soils.

  9. Heavy metals content of municipal wastewater and sludges in Kuwait.

    PubMed

    Al Enezi, G; Hamoda, M F; Fawzi, N

    2004-01-01

    Municipal wastewater may contain heavy metals, which are hazardous to the environment and humans. With stringent regulations concerning water reuse and sludge utilization in agriculture, there is a great need to determine levels of heavy metals in liquid wastes, sludges and agricultural crops. The state of Kuwait has programs to utilize waste sludge produced at wastewater treatment plants as soil conditioner and fertilizer for greenery and agricultural development projects and to reuse treated wastewater effluents in irrigation. The common metals found in Kuwait's raw wastewater and sludge are Cd, Cr, Cu, Hg, Ni, Pb, and Zn. The effects of accumulation of heavy metals in soil are long lasting and even permanent. In this study, the variations in the concentration levels of heavy metals were measured in wastewater and sludge produced at Ardiya municipal wastewater treatment plant in Kuwait. A relationship was observed between the concentrations of heavy metals in treated wastewater and sludge used for agriculture and the level of accumulated heavy metals found in residual tissues of some crops.

  10. Contamination of Polish national parks with heavy metals.

    PubMed

    Staszewski, Tomasz; Łukasik, Włodzimierz; Kubiesa, Piotr

    2012-07-01

    The paper presents results of screening analysis of all Polish national parks (23) contamination with Cd, Cu, Pb and Zn on the basis of a three-level characteristic of heavy metal presence in Norway spruce stands: accumulation on the needle surface, concentration of heavy metals in spruce needles and concentration of bioavailable heavy metals in the soil. Based on the obtained results, the classification of forest ecosystem hazard in national parks with heavy metals was made using synthetic indicators. It was found out that Babiogórski, Magurski, Ojcowski and Gorczański National Parks, located in the southern part of the country, were the most polluted with heavy metals. It is probably due to a higher industrial activity in this part of Poland and the transboundary transport of air pollutants. A little lower level of pollution was observed in Kampinoski National Park located in the middle of the country. The concentration of heavy metals found in needles from national parks does not seem to be harmful for the health status of the trees. Statistically significant correlation between all parameters, which was found for cadmium--the most mobile of the analysed elements--shows that this metal can be proposed as a marker to reflect present effect of industrial emission on forests.

  11. Heavy metals in livers and kidneys of goats in Alabama

    SciTech Connect

    Khan, A.T.; Diffay, B.C.; Datiri, B.C.

    1995-10-01

    The popularity of goat farming is increasing in the southeastern region of the United States. Baseline values of Hg, Pb, and Cd are not available in goat tissues in the United States. These values are needed when monitoring food for heavy metal contamination which may be associated with urbanization and industrialization. Due to human activities or anthropogenic sources of metals in the environment, high concentrations of these metals have been observed in herbage and animal tissues. It has also been reported that toxic heavy metals are concentrated mostly in kidneys and livers of animals. The risk of exposure of humans to heavy metals contained in edible organs of animals has received widespread concern. The objectives of this study were to (i) measure the levels of Hg,Pb, and Cd in livers and kidneys of goats; and (ii) determine whether accumulation of these metals is related to age and/or sex. 20 refs., 3 tabs.

  12. Mechanism for alkali metal-catalyzed CO/sub 2/ gasification of carbon

    SciTech Connect

    Saber, J.M.

    1987-01-01

    Alkali metal-catalyzed gasification of carbon by CO/sub 2/ was studied using Temperature-programmed reaction and isotopic tracers. Between 500 and 1000 K, oxide groups on the carbon surface interact with potassium carbonate to form carbonate/oxygen/carbon complexes. The complexes exchange carbon and oxygen isotopes readily with gas-phase carbon dioxide. Sodium carbonate, however, does not appear to complex with the surface oxide groups under these conditions. The surface oxide groups also stabilize potassium on the carbon surface, thus, less potassium volatilizes from higher-oxygen-content carbons than from lower oxygen content carbons. Above 1000 K, both potassium and sodium carbonate decompose coincident with catalyzed CO/sub 2/ gasification to form a metal oxide with a metal:oxygen ratio of 2. The oxide can be oxidized to give a metal:0 ratio of 1. The carbonate does not appear to be the catalytically active species. Reactions describing Na-catalyzed gasification via oxygen. Transfer mechanisms are proposed.

  13. Detection of heavy metal by paper-based microfluidics.

    PubMed

    Lin, Yang; Gritsenko, Dmitry; Feng, Shaolong; Teh, Yi Chen; Lu, Xiaonan; Xu, Jie

    2016-09-15

    Heavy metal pollution has shown great threat to the environment and public health worldwide. Current methods for the detection of heavy metals require expensive instrumentation and laborious operation, which can only be accomplished in centralized laboratories. Various microfluidic paper-based analytical devices have been developed recently as simple, cheap and disposable alternatives to conventional ones for on-site detection of heavy metals. In this review, we first summarize current development of paper-based analytical devices and discuss the selection of paper substrates, methods of device fabrication, and relevant theories in these devices. We then compare and categorize recent reports on detection of heavy metals using paper-based microfluidic devices on the basis of various detection mechanisms, such as colorimetric, fluorescent, and electrochemical methods. To finalize, the future development and trend in this field are discussed.

  14. View of interior detail; in kitchen; builtiniron and heavy metal ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of interior detail; in kitchen; built-in-iron and heavy metal clock. - Mare Island Naval Shipyard, Quarters P, Walnut Avenue, northwest corner of Walnut Avenue & Fifth Street, Vallejo, Solano County, CA

  15. DETERMINATION OF HEAVY METALS AND PESTICIDES IN GINSENG PRODUCTS

    EPA Science Inventory

    Medicinal plants may carry residuals of environmentally persistent pesticides or assimilate heavy metals in varying degrees. Several factors may influence contaminant accumulation, including species, level and duration of contaminant exposure, and topography. As part of a progra...

  16. NMR microscopy of heavy metal absorption in calcium alginate beads

    SciTech Connect

    Nestle, N.; Kimmich, R.

    1996-01-01

    In recent years, heavy metal uptake by biopolymer gels, such as Cal-Alginate or chitosan, has been studied by various methods. This is of interest because such materials might be an alternative to synthetical ion-exchange resins in the treatment of industrial waste waters. Most of the work done in this field consisted of studies of equilibrium absorption of different heavy metal ions with dependence on various experimental parameters. In some publications, the kinetics of absorption were studied, too. However, no experiments on the spatial distribution of heavy metals during the absorption process are known to us. Using Cu as an example, it is demonstrated in this article that NMR microscopy is an appropriate tool for such studies. By the method presented here, it is possible to monitor the spatial distribution of heavy metal ions with a time resolution of about 5 min and a spatial resolution of 100 {mu}m or even better. 14 refs., 10 figs.

  17. Heavy metals testing in active pharmaceutical ingredients: an alternate approach.

    PubMed

    Raghuram, P; Soma Raju, I V; Sriramulu, J

    2010-01-01

    The principle of the pharmacopoeial heavy metals test is detection and estimation of the metallic impurities colored by sulfide ion by comparison against lead standard. The test suffers from a loss of analytes upon ashing and from having varied responses for various metals. An inductively coupled plasma-optical emission spectroscopy (ICP-OES) for estimating 23 metals in active pharmaceutical ingredients is being proposed. The method covers the metals listed in USP, Ph. Eur and EMEA guidance on "Residues of Metal Catalysts or Metal Reagents".

  18. Combined toxicity of heavy metal mixtures in liver cells.

    PubMed

    Lin, Xialu; Gu, Yuanliang; Zhou, Qi; Mao, Guochuan; Zou, Baobo; Zhao, Jinshun

    2016-09-01

    With rapid industrialization, China is now facing great challenges in heavy metal contamination in the environment. Human exposure to heavy metals through air, water and food commonly involves a mixture consisting of multiple heavy metals. In this study, eight common heavy metals (Pb, Cd, Hg, Cu, Zn, Mn, Cr, Ni) that cause environmental contamination were selected to investigate the combined toxicity of different heavy metal mixtures in HL7702 cells. Toxicity (24 h LC50 ) of each individual metal on the cells ranked Hg > Cr = Cd > Cu > Zn > Ni > Mn > Pb; toxicity of the different mixtures ranked: M5 > M3PbHgCd > M5+Mn > M5+Cu > M2CdNi > M4A > M8-Mn > M8 > M5+Zn > M4B > M8-Cr > M8-Zn > M8-Cu > M8-Pb > M8-Cd > M8-Hg > M8-Ni > M3PbHgNi > M3CuZnMn. The cytotoxicity data of individual metals were successfully used to build the additive models of two- to eight-component metal mixtures. The comparison between additive model and combination model or partly additive model was useful to evaluate the combined effects in mixture. Synergistic, antagonistic or additive effects of the toxicity were observed in different mixtures. These results suggest that the combined effects should be considered in the risk assessment of heavy metal co-exposure, and more comprehensive investigations on the combined effects of different heavy metal mixtures are needed in the future. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Adsorption properties of carbon materials produced by thermolysis of brown coal in the presence of alkali metal hydroxides

    SciTech Connect

    Tamarkina, Y.V.; Maslova, L.A.; Khabarova, T.V.; Kucherenko, V.A.

    2008-07-15

    Activated carbons produced by thermolysis of brown coal impregnated with an alkali metal hydroxide MOH (M = Li, Na, K) at an MOH/coal ratio R-MOH = 80 mol kg{sup -1} were studied. Dependences of the adsorption capacities for iodine and Methylene Blue dye, specific surface area, and yield of activated carbons on the ratio R-MOH were obtained.

  20. Alkali-metal-catalyzed addition of primary and secondary phosphines to carbodiimides. A general and efficient route to substituted phosphaguanidines.

    PubMed

    Zhang, Wen-Xiong; Nishiura, Masayoshi; Hou, Zhaomin

    2006-09-28

    Organo alkali metal compounds such as (n)BuLi and (Me3Si)2NK act as excellent catalyst precursors for the addition of phosphine P-H bonds to carbodiimides, offering a general and atom-economical route to substituted phosphaguanidines, with excellent tolerability to aromatic C-Br and C-Cl bonds.

  1. Phytoremediation of heavy metals in a tropical impoundment of industrial region.

    PubMed

    Rai, Prabhat Kumar

    2010-06-01

    Aquatic pollution poses a serious challenge to the scientific community worldwide, since lakes or reservoirs find multifarious use and most often their water is used for drinking, bathing, irrigation, and aquaculture. Nine metals and several physicochemical parameters, from four sampling sites in a tropical lake receiving the discharges from a thermal power plant, a coal mine, and a chlor-alkali industry, were studied from 2004 to 2005. Pertaining to metal pollution, the site most polluted with heavy metals was Belwadah, i.e., waters and sediments had the highest concentration of all the metals examined. The reference site was characterized by the presence of low concentrations of metals in waters and sediments. Following the water quality monitoring, 2-month field phytoremediation experiments were conducted using large enclosures at the discharge point of different polluted sites of the lake. During field phytoremediation experiments using aquatic macrophytes, marked percentage reduction in metals concentrations were recorded. The percentage decrease for different metals was in the range of 25% to 67.90% at Belwadah (with Eichhornia crassipes and Lemna minor), 25% to 77.14% at Dongia nala (with E. crassipes, L. minor and Azolla pinnata), and 25% to 71.42% at Ash pond site of G.B. Pant Sagar (with L. minor and A. pinnata). Preliminary studies of polluted sites are useful for improved microcosm design and for the systematic extrapolation of information from experimental ecosystems to natural ecosystems.

  2. Variation in dry grassland communities along a heavy metals gradient.

    PubMed

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

    2016-01-01

    The aim of this study was to investigate the variation in plant communities growing on metal-enriched sites created by historical Zn–Pb mining. The study sites were 65 small heaps of waste rock covered by grassland vegetation and scattered mostly over agricultural land of southern Poland. The sites were described in terms of plant coverage, species richness and composition, and the composition of plant traits. They were classified using phytosociological methods and detrended correspondence analysis. Identified plant communities were compared for vegetation parameters and habitat properties (soil characteristics, distance from the forest) by analysis of variance. The variation in plant community parameters was explained by multiple regression, in which the predictors were properties of the habitat selected on the basis of factor analysis. Grasslands that developed at low and high concentrations of heavy metals in soil were similar to some extent: they were composed on average of 17–20 species (per 4 m(2)), and their total coverage exceeded 90%. The species composition changed substantially with increasing contamination with heavy metals; metal-sensitive species withdrew, while the metal-tolerant became more abundant. Other important predictors of community structure were: proximity to the forest (responsible for the encroachment of competitive forest species and ruderals), and the thickness of the surface soil (shallow soil favored the formation of the heavy metal grassland). The heavy metal grassland was closely related to the dry calcareous grasslands. The former was an earlier succession stage of the latter at low contamination with heavy metals.

  3. Human health risk assessment of heavy metals in urban stormwater.

    PubMed

    Ma, Yukun; Egodawatta, Prasanna; McGree, James; Liu, An; Goonetilleke, Ashantha

    2016-07-01

    Toxic chemical pollutants such as heavy metals (HMs) are commonly present in urban stormwater. These pollutants can pose a significant risk to human health and hence a significant barrier for urban stormwater reuse. The primary aim of this study was to develop an approach for quantitatively assessing the risk to human health due to the presence of HMs in stormwater. This approach will lead to informed decision making in relation to risk management of urban stormwater reuse, enabling efficient implementation of appropriate treatment strategies. In this study, risks to human health from heavy metals were assessed as hazard index (HI) and quantified as a function of traffic and land use related parameters. Traffic and land use are the primary factors influencing heavy metal loads in the urban environment. The risks posed by heavy metals associated with total solids and fine solids (<150μm) were considered to represent the maximum and minimum risk levels, respectively. The study outcomes confirmed that Cr, Mn and Pb pose the highest risks, although these elements are generally present in low concentrations. The study also found that even though the presence of a single heavy metal does not pose a significant risk, the presence of multiple heavy metals could be detrimental to human health. These findings suggest that stormwater guidelines should consider the combined risk from multiple heavy metals rather than the threshold concentration of an individual species. Furthermore, it was found that risk to human health from heavy metals in stormwater is significantly influenced by traffic volume and the risk associated with stormwater from industrial areas is generally higher than that from commercial and residential areas.

  4. Distribution of heavy metals from flue gas in algal bioreactor

    NASA Astrophysics Data System (ADS)

    Napan, Katerine

    Flue gas from coal-fired power plants is a major source of CO2 to the atmosphere. Microalgae can use this enriched form of CO2 as carbon source and in turn the biomass can be used to produce food, feed, fertilizer and biofuels. However, along with CO2, coal-based flue gas will inevitably introduce heavy metals, which have a high affinity to bind algal cells, could be toxic to the organisms and if transferred to the products could limit their uses. This study seeks to address the distribution and impact of heavy metals present in flue gas on microalgae production systems. To comprehend its effects, algae Scenedesmus obliquus was grown in batch reactors in a multimetal system. Ten heavy metals (Cu, Co, Zn, Pb, As, Se, Cr, Hg, Ni and Cd) were selected and were evaluated at four concentrations (1X, 2X, 5X and 10X). Results show that most heavy metals accumulated mainly in biomass and were found in very low concentrations in media. Hg was shown to be lost from the culture, with low amounts present in the biomass. An upper limit for As uptake was observed, suggesting its likelihood to build-up in the system during medium recycle. The As limited bioaccumulation was overcome by addition of sulfur to the algal medium. Heavy metal at 2X, 5X and 10X inhibited both growth and lipid production, while at the reference concentration both biomass and lipids yields were increased. Heavy metal concentrations in the medium and biomass were time dependent, and at the end of the cultivation most heavy metals in the supernatant solution complied with the recommendations for irrigation water, while biomass was below limits for cattle and poultry feed, fertilizer, plastic and paper. This research shows that bioremediation of CO2 and heavy metals in combination with energy production can be integrated, which is an environmentally friendly form of biotechnology.

  5. Heavy metal music and drug abuse in adolescents.

    PubMed

    King, P

    1988-04-01

    A large number of adolescents in a psychiatric population, particularly those who are chemically dependent, prefer to listen to heavy metal music. Young people who do not identify with traditional values may find simple but unconventional answers to complex problems in the lyrics of this type of music. While a clearcut relationship cannot be established between heavy metal music and destructive behavior, evidence shows that such music promotes and supports patterns of drug abuse, promiscuous sexual activity, and violence.

  6. An optical dosimeter for monitoring heavy metal ions in water

    NASA Astrophysics Data System (ADS)

    Mignani, Anna G.; Regan, Fiona; Leamy, D.; Mencaglia, A. A.; Ciaccheri, L.

    2005-05-01

    This work presents an optochemical dosimeter for determining and discriminating nickel, copper, and cobalt ions in water that can be used as an early warning system for water pollution. An inexpensive fiber optic spectrophotometer monitors the sensor's spectral behavior under exposure to water solutions of heavy metal ions in the 1-10 mg/l concentration range. The Principal Component Analysis (PCA) method quantitatively determines the heavy metals and discriminates their type and combination.

  7. Staining of Tissue Sections for Electron Microscopy with Heavy Metals

    PubMed Central

    Watson, Michael L.

    1958-01-01

    Heavy metals may be incorporated from solution into tissue sections for electron microscopy. The resulting increase in density of the tissue provides greatly enhanced contrast with minimal distortion. Relative densities of various structures are found to depend on the heavy metal ions present and on the conditions of staining. Certain hitherto unobserved details are revealed and some sort of specificity exists, although the factors involved are not yet understood. PMID:13563554

  8. Spin-exchange frequency shift in alkali-metal-vapor cell frequency standards

    SciTech Connect

    Micalizio, Salvatore; Godone, Aldo; Levi, Filippo; Vanier, Jacques

    2006-03-15

    In this paper we calculate the effect of spin-exchange collisions in alkali-metal vapors. In the framework of the high-energy approximation, we evaluate the spin-exchange cross sections related to the line broadening and to the frequency shift of the ground state hyperfine transition. We do the calculation for the four isotopes, {sup 23}Na, {sup 39}K, {sup 87}Rb, and {sup 133}Cs. The results are used in particular to evaluate the spin-exchange frequency shift in Rb vapor cell frequency standards used in many applications. It turns out that, due to possible fluctuations in the atomic density, spin exchange may affect significantly the medium and long term frequency stability of the frequency standard.

  9. Infrared spectroscopy of hydrated alkali metal cations: Evidence of multiple photon absorption

    NASA Astrophysics Data System (ADS)

    Beck, Jordan P.; Lisy, James M.

    2011-07-01

    Infrared predissociation spectra of M+(H2O)4-7, where M = alkali metal, are presented. Hydrogen bonding O-H stretching features are strongly dependent on which fragmentation channel is monitored. Spectra recorded by monitoring the loss of multiple waters show a preference for one absorption feature in the hydrogen-bonded region centered at ˜3430-3500 cm-1, which is assigned to linear-type hydrogen bonded OH stretches. Cyclic- and bent-type hydrogen bonded OH stretches have diminished photodissociation cross sections in the multiple ligand loss channels. Evidence from Rice-Ramsperger-Kassel-Marcus-evaporative ensemble calculations and laser fluence dependence experiments indicates that the multiple water loss channels are primarily the result of multiple photon absorption which we propose could be due to multiple, independent oscillators within a cluster ion each absorbing a photon during a single, 10 ns laser pulse.

  10. s-wave elastic scattering of antihydrogen off atomic alkali-metal targets

    SciTech Connect

    Sinha, Prabal K.; Ghosh, A. S.

    2006-03-15

    We have investigated the s-wave elastic scattering of antihydrogen atoms off atomic alkali-metal targets (Li, Na, K, and Rb) at thermal energies (10{sup -16}-10{sup -4} a.u.) using an atomic orbital expansion technique. The elastic cross sections of these systems at thermal energies are found to be very high compared to H-H and H-He systems. The theoretical models employed in this study are so chosen to consider long-range forces dynamically in the calculation. The mechanism of cooling suggests that Li may be considered to be a good candidate as a buffer gas for enhanced cooling of antihydrogen atoms to ultracold temperature.

  11. Silicon Halide-alkali Metal Flames as a Source of Solar Grade Silicon

    NASA Technical Reports Server (NTRS)

    Olson, D. B.; Gould, R. K.

    1979-01-01

    A program is presented which was aimed at determining the feasibility of using high temperature reactions of alkali metals and silicon halides to produce low cost solar-grade silicon. Experiments are being conducted to evaluate product separation and collection processes, measure heat release parameters for scaling purposes, and determine the effects of the reactants and/or products on materials of reactor construction. During the current reporting period, the results of heat release experiments were used to design and construct a new type of thick-wall graphite reactor to produce larger quantities of silicon. A reactor test facility was constructed. Material compatibility tests were performed for Na in contact with graphite and several coated graphites. All samples were rapidly degraded at T = 1200K, while samples retained structural strength at 1700K. Pyrolytic graphite coatings cracked and separated from substances in all cases.

  12. Sputtering and secondary ion emission properties of alkali metal films and adsorbed monolayers

    SciTech Connect

    Krauss, A R; Gruen, D M

    1980-01-01

    The secondary ion emission of alkali metal adsorbed monlayer and multilayer films has been studied. Profiling with sub-monolayer resolution has been performed by Auger, x-ray photoemission and secondary ion mass spectroscopy. Characteristic differences in the sputtering yields, and ion fraction have been observed which are associated with both the surface bonding properties and the mechanism leading to the formation of secondary ions. By sputtering with a negative bias applied to the sample, positive secondary ions are returned to the surface, resulting in a reduced sputter-induced erosion rate. Comparison with the results obtained with K and Li overlayers sputtered without sample bias provides an experimental value of both the total and secondary ion sputtering yields. The first and second monolayers can be readily identified and the first monolayer exhibits a lower sputtering yield and higher secondary ion fraction. This result is related to adsorption theory and measured values are compared with those obtained by thermal desorption measurements.

  13. Voltammetric studies of porous molybdenum electrodes for the alkali metal thermoelectric converter

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Bankston, C. P.; Khanna, S. K.; Cole, T.

    1986-01-01

    Voltammetry of partially oxidized porous molybdenum alkali metal thermoelectric converter (AMTEC) electrodes from about 600 to 1000 K revealed a series of redox processes within the AMTEC operational voltage range which can be used to establish the electronic and ionic conductivities of these electrodes. Improved estimates of the free energies of formation of Na2Mo3O6, NaMoO2, and Na3MoO4 are obtained. Evidence is provided for the slow corrosive attack by Na2MoO4 on molybdenum. The ionic conductivity of Na2MoO4 is found to be sufficiently large at temperatures of greater than 700 K to explain the observed electrochemical phenomena in addition to the enhanced sodium transport in AMTEC electrodes below the freezing point of Na2MoO4.

  14. Magnetism in alkali-metal-doped wurtzite semiconductor materials controlled by strain engineering

    NASA Astrophysics Data System (ADS)

    Guo, J. H.; Li, T. H.; Liu, L. Z.; Hu, F. R.

    2016-09-01

    The study of the magnetism and optical properties of semiconductor materials by defect engineering has attracted much attention because of their potential uses in spintronic and optoelectronic devices. In this paper, first-principle calculations discloses that cationic vacancy formation energy of the doped wurtzite materials can be sharply decreased due to alkali metal dopants and shows that their magnetic properties strongly depend on defect and doping concentration. This effect can be ascribed to the volume change induced by foreign elements doped into the host system and atomic population's difference. The symmetric deformation induced by biaxial strain can further regulate this behavior. Our results suggest that the formation of cationic vacancy can be tailored by strain engineering and dopants incorporation.

  15. Green's-function approach to nonresonance multiphoton absorption in the alkali-metal atoms

    NASA Astrophysics Data System (ADS)

    McGuire, E. J.

    1981-01-01

    An exact Green's function is constructed for the one-electron Schrödinger equation using a central potential obtained from a piecewise linear approximation to -rV(r) of Herman and Skillman. With the Green's function two- and three-photon ionization cross sections are calculated for He(1s)(2s) 1S, 3S, and the alkali metals, and compared to other calculations and experiments. Resonances in the cross sections occur at model eigenvalues rather than experimental energy levels. It is demonstrated that the resonances can be made to occur at experimental values either by simple shifts in the wavelength scale, by adjusting the ionization energy in the calculation, or by including the eigenvalue differences in a finite sum. However, as these are perturbation-theory calculations and not applicable at very high intensities or on resonance, only the wings of the resonance structure are included in the calculation.

  16. Alkali-metal electron spin density shift induced by a helium nanodroplet

    NASA Astrophysics Data System (ADS)

    Koch, Markus; Callegari, Carlo; Ernst, Wolfgang E.

    2010-04-01

    Helium (He) nanodroplets provide a cold and virtually unperturbing environment for the study of weakly bound molecules and van der Waals aggregates. High resolution microwave spectroscopy and the detection of electron spin transitions in doped He droplets have recently become possible. Measurements of hyperfine-resolved electron spin resonance in potassium (39K) and rubidium (85Rb) atoms on the surface of He droplets show small line shifts relative to the bare atoms. These shifts were recorded for all 2I + 1 components (I is the nuclear spin) of a transition at high accuracy for He droplets ranging in size from 1000 to 15,000 He atoms. Evaluation of the spectra yields the influence of the He environment on the electron spin density at the alkali-metal nucleus. A semi-empirical model is presented that shows good qualitative agreement with the measured droplet size dependent increase of Fermi contact interaction at the nuclei of dopant K and Rb.

  17. Alkali metal compatibility testing of candidate heater head materials for a Stirling engine heat transport system

    NASA Technical Reports Server (NTRS)

    Noble, Jack E.; Hickman, Gary L.; Grobstein, Toni

    1991-01-01

    The authors describe work performed as part of the 25-kWe advanced Stirling conversion system project. Liquid alkali metal compatibility is being assessed in an ongoing test program to evaluate candidate heater head materials and fabrication processes at the temperatures and operating conditions required for Stirling engines. Specific materials under evaluation are alloy 713LC, alloy 713LC coated with nickel aluminide, and Udimet 720, each in combination with Waspaloy. The tests were run at a constant 700 C. A eutectic alloy of sodium and potassium (NaK) was the working fluid. Titanium sheet in the system was shown to be an effective oxygen getter. Metallographic and microchemical examination of material surfaces, joints, and their interfaces revealed little or no corrosion after 1000 h. Tests are in progress, with up to 10,000 h exposure.

  18. Thermal characterization of an AMTEC recirculating test cell. [Alkali Metal ThermoElectric Converter

    NASA Technical Reports Server (NTRS)

    Underwood, M. L.; O'Connor, D.; Williams, R. M.; Jeffries-Nakamura, B.; Ryan, M. A.; Bankston, C. P.

    1990-01-01

    An alkali metal thermoelectric converter (AMTEC) recirculating test cell has been operated in order to determine the magnitudes of the primary heat losses of the cell and the value of the emissivity of the condenser surface. The energy balance included radiation losses, conductive losses, and losses due to the flow of sodium into the cell. The radiative heat flux dominated the heat loss mechanism of the cell at open circuit, and the condenser emissivity was calculated to be about 0.1. It is shown that, if this emissivity can be reduced to 0.02, then parasitic losses in an AMTEC recirculating test cell operating near peak power would be less than 40 percent of the heat required by the cell. The condenser emissivity decreases with elapsed time, resulting in improved thermal performance of the cell.

  19. Heavy metal pollution in aquatic ecosystems and its phytoremediation using wetland plants: an ecosustainable approach.

    PubMed

    Rai, Prabhat Kumar

    2008-01-01

    This review addresses the global problem of heavymetal pollution originating from increased industrialization and urbanization and its amelioration by using wetland plants both in a microcosm as well as natural/field condition. Heavymetal contamination in aquatic ecosystems due to discharge of industrial effluents may pose a serious threat to human health. Alkaline precipitation, ion exchange columns, electrochemical removal, filtration, and membrane technologies are the currently available technologies for heavy metal removal. These conventional technologies are not economical and may produce adverse impacts on aquatic ecosystems. Phytoremediation of metals is a cost-effective "green" technology based on the use of specially selected metal-accumulating plants to remove toxic metals from soils and water. Wetland plants are important tools for heavy metal removal. The Ramsar convention, one of the earlier modern global conservation treaties, was adopted at Ramsar, Iran, in 1971 and became effective in 1975. This convention emphasized the wise use of wetlands and their resources. This review mentions salient features of wetland ecosystems, their vegetation component, and the pros and cons involved in heavy metal removal. Wetland plants are preferred over other bio-agents due to their low cost, frequent abundance in aquatic ecosystems, and easy handling. The extensive rhizosphere of wetland plants provides an enriched culture zone for the microbes involved in degradation. The wetland sediment zone provides reducing conditions that are conducive to the metal removal pathway. Constructed wetlands proved to be effective for the abatement of heavymetal pollution from acid mine drainage; landfill leachate; thermal power; and municipal, agricultural, refinery, and chlor-alkali effluent. the physicochemical properties of wetlands provide many positive attributes for remediating heavy metals. Typha, Phragmites, Eichhornia, Azolla, Lemna, and other aquatic macrophytes are some

  20. Intracellular acidification-induced alkali metal cation/H+ exchange in human neutrophils

    PubMed Central

    1987-01-01

    Pretreatment of isolated human neutrophils (resting pHi congruent to 7.25 at pHo 7.40) with 30 mM NH4Cl for 30 min leads to an intracellular acidification (pHi congruen to 6.60) when the NH4Cl prepulse is removed. Thereafter, in 140 mM Na+ medium, pHi recovers exponentially with time (initial rate, approximately 0.12 pH/min) to reach the normal resting pHi by approximately 20 min, a process that is accomplished mainly, if not exclusively, though an exchange of internal H+ for external Na+. This Na+/H+ countertransport is stimulated by external Na+ (Km congruent to 21 mM) and by external Li+ (Km congruent to 14 mM), though the maximal transport rate for Na+ is about twice that for Li+. Both Na+ and Li+ compete as substrates for the same translocation sites on the exchange carrier. Other alkali metal cations, such as K+, Rb+, or Cs+, do not promote pHi recovery, owing to an apparent lack of affinity for the carrier. The exchange system is unaffected by ouabain or furosemide, but can be competitively inhibited by the diuretic amiloride (Ki congruent to 8 microM). The influx of Na+ or Li+ is accompanied by an equivalent counter-reflux of H+, indicating a 1:1 stoichiometry for the exchange reaction, a finding consistent with the lack of voltage sensitivity (i.e., electroneutrality) of pHi recovery. These studies indicate that the predominant mechanism in human neutrophils for pHi regulation after intracellular acidification is an amiloride-sensitive alkali metal cation/H+ exchange that shares a number of important features with similar recovery processes in a variety of other mammalian cell types. PMID:3694176

  1. Heavy metal ions are potent inhibitors of protein folding

    SciTech Connect

    Sharma, Sandeep K.; Goloubinoff, Pierre; Christen, Philipp

    2008-07-25

    Environmental and occupational exposure to heavy metals such as cadmium, mercury and lead results in severe health hazards including prenatal and developmental defects. The deleterious effects of heavy metal ions have hitherto been attributed to their interactions with specific, particularly susceptible native proteins. Here, we report an as yet undescribed mode of heavy metal toxicity. Cd{sup 2+}, Hg{sup 2+} and Pb{sup 2+} proved to inhibit very efficiently the spontaneous refolding of chemically denatured proteins by forming high-affinity multidentate complexes with thiol and other functional groups (IC{sub 50} in the nanomolar range). With similar efficacy, the heavy metal ions inhibited the chaperone-assisted refolding of chemically denatured and heat-denatured proteins. Thus, the toxic effects of heavy metal ions may result as well from their interaction with the more readily accessible functional groups of proteins in nascent and other non-native form. The toxic scope of heavy metals seems to be substantially larger than assumed so far.

  2. Comparison of Eleven Heavy Metals in Moringa Oleifera Lam. Products

    PubMed Central

    Limmatvapirat, C.; Limmatvapirat, S.; Charoenteeraboon, J.; Wessapan, C.; Kumsum, A.; Jenwithayaamornwech, S.; Luangthuwapranit, P.

    2015-01-01

    Eleven heavy metals in various products of Moringa oleifera were analyzed to determine eleven heavy metals (Al, As, Cd, Cr, Cu, Fe, Pb, Mn, Hg, Ni, and Zn) using Inductively Coupled Plasma-Mass Spectrometry. The products of M. oleifera were purchased in Nakhon Pathom, Thailand. All products were digested with nitric acid solution before determining the concentrations of heavy metals. The recoveries of all heavy metals were found to be in the range of 99.89-103.05%. Several criteria such as linearity, limits of detection, limits of quantification, specificity, precision under repeatability conditions and intermediate precision reproducibility were evaluated. Results indicate that this method could be used in the laboratory for determination of eleven heavy metals in M. oleifera products with acceptable analytical performance. The results of analysis showed that the highest concentrations of As, Cr, Hg, and Mn were found in tea leaves while the highest concentrations of Al, Cd, Cu, Fe, Ni, Pb, and Zn were found in leaf capsules. Continuous monitoring of heavy metals in M. oleifera products is crucial for consumer health. PMID:26664066

  3. Isolation and characterization of a heavy metal-resistant Burkholderia sp. from heavy metal-contaminated paddy field soil and its potential in promoting plant growth and heavy metal accumulation in metal-polluted soil.

    PubMed

    Jiang, Chun-yu; Sheng, Xia-fang; Qian, Meng; Wang, Qing-ya

    2008-05-01

    A heavy metal-resistant bacterial strain was isolated from heavy metal-contaminated soils and identified as Burkholderia sp. J62 based on the 16S rDNA gene sequence analysis. The heavy metal- and antibiotic resistance, heavy metal solubilization of the isolate were investigated. The isolate was also evaluated for promoting plant growth and Pb and Cd uptakes of the plants from heavy metal-contaminated soils in pot experiments. The isolate was found to exhibit different multiple heavy metal and antibiotic resistance characteristics. Atomic absorption spectrometer analysis showed increased bacterial solubilization of lead and cadmium in solution culture and in soils. The isolate produced indole acetic acid, siderophore and 1-aminocyclopropane-1-carboxylate deaminase. The isolate also solubilized inorganic phosphate. Inoculation with the isolate was found to significantly (p<0.05) increase the biomass of maize and tomato plants. Increase in tissue Pb and Cd contents varied from 38% to 192% and from 5% to 191% in inoculated plants growing in heavy metal-contaminated soils compared to the uninoculated control, respectively. These results show that heavy metal-solubilizing and plant growth promoting bacteria are important for plant growth and heavy metal uptake which may provide a new microbial enhanced-phytoremediation of metal-polluted soils.

  4. Alkali metal vapor removal from pressurized fluidized-bed combustor flue gas. Quarterly report, October-December 1979

    SciTech Connect

    Johnson, I.; Swift, W.M.; Lee, S.H.D.; Jonke, A.A.

    1980-07-01

    This work supports the program to develop methods for the cleanup of combustion gases from pressurized fluidized-bed coal combustors so that the cleaned gases can be used for downstream gas turbines. This report presents the results of studies to develop granular sorbents for removing gaseous alkali metal compounds from high-temperature high-pressure combustion gases. Activated bauxite, one of the sorbents found to be effective, can be reused after removal of the alkali compound by a water-leaching process. Results of testing of this leaching process are reported. An experimental appartus for testing sorbents at high pressure has been built; results of preliminary tests are reported.

  5. Hydrogen generation using silicon nanoparticles and their mixtures with alkali metal hydrides

    NASA Astrophysics Data System (ADS)

    Patki, Gauri Dilip

    mole of Si. We compare our silicon nanoparticles (˜10nm diameter) with commercial silicon nanopowder (<100nm diameter) and ball-milled silicon powder (325 mesh). The increase in rate upon decreasing the particle size to 10 nm was even greater than would be expected based upon the increase in surface area. While specific surface area increased by a factor of 6 in going from <100 nm to ˜10 nm particles, the hydrogen production rate increased by a factor of 150. However, in all cases, silicon requires a base (e.g. NaOH, KOH, hydrazine) to catalyze its reaction with water. Metal hydrides are also promising hydrogen storage materials. The optimum metal hydride would possess high hydrogen storage density at moderate temperature and pressure, release hydrogen safely and controllably, and be stable in air. Alkali metal hydrides have high hydrogen storage density, but exhibit high uncontrollable reactivity with water. In an attempt to control this explosive nature while maintaining high storage capacity, we mixed our silicon nanoparticles with the hydrides. This has dual benefits: (1) the hydride- water reaction produces the alkali hydroxide needed for base-catalyzed silicon oxidation, and (2) dilution with 10nm coating by, the silicon may temper the reactivity of the hydride, making the process more controllable. Initially, we analyzed hydrolysis of pure alkali metal hydrides and alkaline earth metal hydrides. Lithium hydride has particularly high hydrogen gravimetric density, along with faster reaction kinetics than sodium hydride or magnesium hydride. On analysis of hydrogen production we found higher hydrogen yield from the silicon nanoparticle—metal hydride mixture than from pure hydride hydrolysis. The silicon-hydride mixtures using our 10nm silicon nanoparticles produced high hydrogen yield, exceeding the theoretical yield. Some evidence of slowing of the hydride reaction rate upon addition of silicon nanoparticles was observed.

  6. Heavy metal music meets complexity and sustainability science.

    PubMed

    Angeler, David G

    2016-01-01

    This paper builds a bridge between heavy metal music, complexity theory and sustainability science to show the potential of the (auditory) arts to inform different aspects of complex systems of people and nature. The links are described along different dimensions. This first dimension focuses on the scientific aspect of heavy metal. It uses complex adaptive systems theory to show that the rapid diversification and evolution of heavy metal into multiple subgenres leads to a self-organizing and resilient socio-musicological system. The second dimension builds on the recent use of heavy metal as a critical thinking model and educational tool, emphasizing the artistic component of heavy metal and its potential to increase people's awareness of environmental sustainability challenges. The relationships between metal, complexity theory and sustainability are first discussed independently to specifically show mechanistic links and the reciprocal potential to inform one domain (science) by the other (metal) within these dimensions. The paper concludes by highlighting that these dimensions entrain each other within a broader social-cultural-environmental system that cannot be explained simply by the sum of independent, individual dimensions. Such a unified view embraces the inherent complexity with which systems of people and nature interact. These lines of exploration suggest that the arts and the sciences form a logical partnership. Such a partnership might help in endeavors to envision, understand and cope with the broad ramifications of sustainability challenges in times of rapid social, cultural, and environmental change.

  7. Electrokinetic treatment of an agricultural soil contaminated with heavy metals.

    PubMed

    Figueroa, Arylein; Cameselle, Claudio; Gouveia, Susana; Hansen, Henrik K

    2016-07-28

    The high organic matter content in agricultural soils tends to complex and retain contaminants such as heavy metals. Electrokinetic remediation was tested in an agricultural soil contaminated with Co(+2), Zn(+2), Cd(+2), Cu(+2), Cr(VI), Pb(+2) and Hg(+2). The unenhanced electrokinetic treatment was not able to remove heavy metals from the soil due to the formation of precipitates in the alkaline environment in the soil section close to the cathode. Moreover, the interaction between metals and organic matter probably limited metal transportation under the effect of the electric field. Citric acid and ethylenediaminetetraacetic acid (EDTA) were used in the catholyte as complexing agents in order to enhance the extractability and removal of heavy metals from soil. These complexing agents formed negatively charged complexes that migrated towards the anode. The acid front electrogenerated at the anode favored the dissolution of heavy metals that were transported towards the cathode. The combined effect of the soil pH and the complexing agents resulted in the accumulation of heavy metals in the center of the soil specimen.

  8. Phytoremediation of heavy metals--concepts and applications.

    PubMed

    Ali, Hazrat; Khan, Ezzat; Sajad, Muhammad Anwar

    2013-05-01

    The mobilization of heavy metals by man through extraction from ores and processing for different applications has led to the release of these elements into the environment. Since heavy metals are nonbiodegradable, they accumulate in the environment and subsequently contaminate the food chain. This contamination poses a risk to environmental and human health. Some heavy metals are carcinogenic, mutagenic, teratogenic and endocrine disruptors while others cause neurological and behavioral changes especially in children. Thus remediation of heavy metal pollution deserves due attention. Different physical and chemical methods used for this purpose suffer from serious limitations like high cost, intensive labor, alteration of soil properties and disturbance of soil native microflora. In contrast, phytoremediation is a better solution to the problem. Phytoremediation is the use of plants and associated soil microbes to reduce the concentrations or toxic effects of contaminants in the environments. It is a relatively recent technology and is perceived as cost-effective, efficient, novel, eco-friendly, and solar-driven technology with good public acceptance. Phytoremediation is an area of active current research. New efficient metal hyperaccumulators are being explored for applications in phytoremediation and phytomining. Molecular tools are being used to better understand the mechanisms of metal uptake, translocation, sequestration and tolerance in plants. This review article comprehensively discusses the background, concepts and future trends in phytoremediation of heavy metals.

  9. Heavy metals in urban soils of East St. Louis, IL, Part I: Total concentration of heavy metals in soils.

    PubMed

    Kaminski, M D; Landsberger, S

    2000-09-01

    The city of East St. Louis, IL, has a history of abundant industrial activities including smelters of ferrous and non-ferrous metals, a coal-fired power plant, companies that produce organic and inorganic chemicals, and petroleum refineries. A protocol for soil analysis was developed to produce sufficient information on the extent of heavy metal contamination in East St. Louis soils. Soil cores representing every borough of East St. Louis were analyzed for heavy metals--As, Cd, Cu, Cr, Hg, Ni, Pb, Sb, Sn, and Zn. The topsoil contained heavy metal concentrations as high as 12.5 ppm Cd, 14,400 ppm Cu, ppm quantities of Hg, 1860 ppm Pb, 40 ppm Sb, 1130 ppm Sn, and 10,360 ppm Zn. Concentrations of Sb, Cu, and Cd were well correlated with Zn concentrations, suggesting a similar primary industrial source. In a sandy loam soil from a vacated rail depot near the bank of the Mississippi River, the metals were evenly distributed down to a 38-cm depth. The clay soils within a half-mile downwind of the Zn smelter and Cu products company contained elevated Cd (81 ppm), Cu (340 ppm), Pb (700 ppm), and Zn (6000 ppm) and displayed a systematic drop in concentration of these metals with depth. This study demonstrates the often high concentration of heavy metals heterogeneously distributed in the soil and provides baseline data for continuing studies of heavy metal soil leachability.

  10. The fate of heavy metals during combustion and gasification of contaminated biomass-a brief review.

    PubMed

    Nzihou, Ange; Stanmore, Brian

    2013-07-15

    The literature on the presence of heavy metals in contaminated wastes is reviewed. Various categories of materials produced from domestic and industrial activities are included, but municipal solid waste, which is a more complex material, is excluded. This review considers among the most abundant the following materials - wood waste including demolition wood, phytoremediation scavengers and chromated copper arsenate (CCA) timber, sludges including de-inking sludge and sewage sludge, chicken litter and spent pot liner. The partitioning of the metals in the ashes after combustion or gasification follows conventional behaviour, with most metals retained, and higher concentrations in the finer sizes due to vaporisation and recondensation. The alkali metals have been shown to catalyse the biomass conversion, particularly lithium and potassium, although other metals are active to a lesser extent. The most prevalent in biomass is potassium, which is not only inherently active, but volatilises to become finely distributed throughout the char mass. Because the metals are predominantly found in the ash, the effectiveness of their removal depends on the efficiency of the collection of particulates. The potential for disposal into soil depends on the initial concentration in the feed material.

  11. Body burdens of heavy metals in Lake Michigan wetland turtles.

    PubMed

    Smith, Dayna L; Cooper, Matthew J; Kosiara, Jessica M; Lamberti, Gary A

    2016-02-01

    Tissue heavy metal concentrations in painted (Chrysemys picta) and snapping (Chelydra serpentina) turtles from Lake Michigan coastal wetlands were analyzed to determine (1) whether turtles accumulated heavy metals, (2) if tissue metal concentrations were related to environmental metal concentrations, and (3) the potential for non-lethal sampling techniques to be used for monitoring heavy metal body burdens in freshwater turtles. Muscle, liver, shell, and claw samples were collected from painted and snapping turtles and analyzed for cadmium, chromium, copper, iron, lead, magnesium, manganese, and zinc. Turtle tissues had measurable quantities of all eight metals analyzed. Statistically significant correlations between tissue metal concentrations and sediment metal concentrations were found for a subset of metals. Metals were generally found in higher concentrations in the larger snapping turtles than in painted turtles. In addition, non-lethal samples of shell and claw were found to be possible alternatives to lethal liver and muscle samples for some metals. Human consumption of snapping turtles presents potential health risks if turtles are harvested from contaminated areas. Overall, our results suggest that turtles could be a valuable component of contaminant monitoring programs for wetland ecosystems.

  12. Biomonitoring heavy metal contaminations by moss visible parameters.

    PubMed

    Chen, Yang-Er; Cui, Jun-Mei; Yang, Jin-Chuan; Zhang, Zhong-Wei; Yuan, Ming; Song, Chun; Yang, Hui; Liu, Han-Mei; Wang, Chang-Quan; Zhang, Huai-Yu; Zeng, Xian-Yin; Yuan, Shu

    2015-10-15

    Traditional sampling for heavy metal monitoring is a time-consuming and inconvenient method, which also does not indicate contaminants non-invasively and instantaneously. Moss is sensitive to heavy metals and is therefore considered a pollution indicator. However, it is unknown what kind physiological parameters can indicate metal contaminations quickly and non-invasively. Here, we systematically examined the effects of six heavy metals on physiological parameters and photosynthetic activities of two moss species grown in aquatic media or moist soil surface. We suggest that a phenotype with anthocyanin accumulation pattern and chlorosis pattern and two chlorophyll fluorescence parameters with their images can roughly reflect metal species groups, concentrations and differences between the two moss species. In other words, metal contaminations could be roughly estimated visually using the naked eye. Enzymatic and non-enzymatic anti-oxidative abilities and photosynthetic protein contents of Eurhynchium eustegium were higher than those of Taxiphyllum taxirameum, indicating their differential metal tolerance. Neither anti-oxidative abilities nor photosynthetic proteins were found to be ideal indicators. This study provides new ideas to monitor heavy metals rapidly and non-invasively in water or on wetland and moist soil surface.

  13. Nitrification and Heavy Metal Removal in the Activated Sludge Treatment Process.

    DTIC Science & Technology

    1976-08-01

    parameters to heavy metal removal in the activated sludge waste treatment process. The heavy metals studied were chromium and silver. Analyses...performed on the influent, mixed liquor, return sludge, and effluent included heavy metal concentration, pH, dissolved oxygen, temperature, suspended solids...related to heavy metal removal. Nitrification is only indirectly related. A theory for the mechanisms contributing to heavy metal removal is developed.

  14. Heavy metals removal from automobile shredder residues (ASR).

    PubMed

    Kurose, Keisuke; Okuda, Tetsuji; Nishijima, Wataru; Okada, Mitsumasa

    2006-10-11

    The fate of heavy metals during a separation process for automobile shredder residues (ASR) was investigated. A washing method to remove heavy metals from the ASR was also investigated. Although the separation process was not designed for removal of heavy metals, but for the recovery of reusable materials, the heavy metal content in the ASR was efficiently decreased. The concentrations of Pb, Cr and Cd in ASR were effectively reduced by a nonferrous metals removal process, and the As concentration was reduced by the removal of light dusts during the separation process. Five heavy metals (As, Se, Pb, Cr, Cd) remaining in the ASR after the separation process satisfied the content criteria of the Environmental Quality Standards for Soil (EQSS), while the concentrations of As, Se, Pb in the leachate from the remaining ASR did not satisfy the elution criteria of the EQSS. After additional washing of the remaining ASR with a pH 1 acid buffer solution, the As, Se, and Pb concentrations satisfied the EQSS for elution. These results indicate that an ASR residue can be safely recycled after a separation process, followed by washing at acidic pH.

  15. Phytochemicals Mediated Remediation of Neurotoxicity Induced by Heavy Metals.

    PubMed

    Gupta, Vivek Kumar; Singh, Shweta; Agrawal, Anju; Siddiqi, Nikhat Jamal; Sharma, Bechan

    2015-01-01

    Almost all the environmental components including both the abiotic and biotic factors have been consistently threatened by excessive contamination of heavy metals continuously released from various sources. Different heavy metals have been reported to generate adverse effects in many ways. Heavy metals induced neurotoxicity and impairment in signalling cascade leading to cell death (apoptosis) has been indicated by several workers. On one hand, these metals are required by the cellular systems to regulate various biological functions of normal cells, while on the other their biomagnification in the cellular systems produces adverse effects. The mechanism by which the heavy metals induce neurotoxicity follows free radicals production pathway(s) specially the generation of reactive oxygen species and reactive nitrogen species. These free radicals produced in excess have been shown to create an imbalance between the oxidative and antioxidative systems leading to emergence of oxidative stress, which may cause necrosis, DNA damage, and many neurodegenerative disorders. This mini review summarizes the current knowledge available on the protective role of varied natural products isolated from different herbs/plants in imparting protection against heavy metals (cadmium, lead, arsenic, and mercury) mediated neurotoxicity.

  16. Multivariate analysis of heavy metals concentrations in river estuary.

    PubMed

    Alkarkhi, Abbas F M; Ahmad, Anees; Ismail, Norli; Easa, Azhar Mat

    2008-08-01

    Multivariate statistical techniques such as multivariate analysis of variance (MANOVA) and discriminant analysis (DA) were applied for analyzing the data obtained from two rivers in the Penang State of Malaysia for the concentration of heavy metal ions (As, Cr, Cd, Zn, Cu, Pb, and Hg) using a flame atomic absorption spectrometry (F-AAS) for Cr, Cd, Zn, Cu, Pb, As and cold vapor atomic absorption spectrometry (CV-AAS) for Hg. The two locations of interest with 20 sampling points of each location were Kuala Juru (Juru River) and Bukit Tambun (Jejawi River). MANOVA showed a strong significant difference between the two rivers in terms of heavy metal concentrations in water samples. DA gave the best result to identify the relative contribution for all parameters in discriminating (distinguishing) the two rivers. It provided an important data reduction as it used four parameters (Zn, Pb, Cd and Cr) affording 100% correct assignations. Results indicated that the two rivers were different in terms of heavy metals concentrations in water, and the major difference was due to the contribution of Zn. A negative correlation was found between discriminate functions (DF) and Cr and As, whereas positive correlation was exhibited with other heavy metals. Therefore, DA allowed a reduction in the dimensionality of the data set, delineating a few indicator parameters responsible for large variations in heavy metal concentrations. Correlation matrix between the parameters exhibited a strong evidence of mutual dependence of these metals.

  17. Physiological sensitivity of freshwater macroinvertebrates to heavy metals.

    PubMed

    Malaj, Egina; Grote, Matthias; Schäfer, Ralf B; Brack, Werner; von der Ohe, Peter Carsten

    2012-08-01

    Macroinvertebrate species traits, such as physiological sensitivity, have successfully been introduced in trait-based bioassessment approaches and are important predictors of species sensitivity in the field. The authors ranked macroinvertebrate species according to their physiological sensitivity to heavy metals using toxicity data from acute laboratory assays. Rankings for each of the heavy metals, Cd, Cu, Cr, Ni, Pb, Zn, and Hg, were standardized based on all available species data. Rankings for different heavy metals on the species level showed no significant difference between compounds and were reasonably well correlated pairwise (0.50heavy metal ranking was developed, which assigns a single physiological sensitivity value (S(metal) ) to macroinvertebrate taxa. Considering the high variation, especially for higher taxonomic levels, that is, in the order level, it is recommended to use S values of the genus or species level for meaningful analyses. In terms of taxonomic ranking, crustaceans were overall the most sensitive taxonomic group, whereas insects were generally the most tolerant group. Species in the order of Cladocera were three orders of magnitude more sensitive than insects of the order of Trichoptera. By contrast, mollusks covered a wide range of sensitivities, with bivalves being on average one order of magnitude more sensitive than gastropods. The authors concluded that physiological sensitivity represents a promising trait for trait-based risk assessment that together with other demographic and recolonization traits may help to identify the effects of heavy metal pollution in aquatic ecosystems.

  18. Magnetic process for removing heavy metals from water employing magnetites

    DOEpatents

    Prenger, F. Coyne; Hill, Dallas D.; Padilla, Dennis D.; Wingo, Robert M.; Worl, Laura A.; Johnson, Michael D.

    2003-07-22

    A process for removing heavy metals from water is provided. The process includes the steps of introducing magnetite to a quantity of water containing heavy metal. The magnetite is mixed with the water such that at least a portion of, and preferably the majority of, the heavy metal in the water is bound to the magnetite. Once this occurs the magnetite and absorbed metal is removed from the water by application of a magnetic field. In most applications the process is achieved by flowing the water through a solid magnetized matrix, such as steel wool, such that the magnetite magnetically binds to the solid matrix. The magnetized matrix preferably has remnant magnetism, but may also be subject to an externally applied magnetic field. Once the magnetite and associated heavy metal is bound to the matrix, it can be removed and disposed of, such as by reverse water or air and water flow through the matrix. The magnetite may be formed in-situ by the addition of the necessary quantities of Fe(II) and Fe(III) ions, or pre-formed magnetite may be added, or a combination of seed and in-situ formation may be used. The invention also relates to an apparatus for performing the removal of heavy metals from water using the process outlined above.

  19. Magnetic process for removing heavy metals from water employing magnetites

    DOEpatents

    Prenger, F. Coyne; Hill, Dallas D.

    2006-12-26

    A process for removing heavy metals from water is provided. The process includes the steps of introducing magnetite to a quantity of water containing heavy metal. The magnetite is mixed with the water such that at least a portion of, and preferably the majority of, the heavy metal in the water is bound to the magnetite. Once this occurs the magnetite and absorbed metal is removed from the water by application of a magnetic field. In most applications the process is achieved by flowing the water through a solid magnetized matrix, such as steel wool, such that the magnetite magnetically binds to the solid matrix. The magnetized matrix preferably has remnant magnetism, but may also be subject to an externally applied magnetic field. Once the magnetite and associated heavy metal is bound to the matrix, it can be removed and disposed of, such as by reverse water or air and water flow through the matrix. The magnetite may be formed in-situ by the addition of the necessary quantities of Fe(II) and Fe(III) ions, or pre-formed magnetite may be added, or a combination of seed and in-situ formation may be used. The invention also relates to an apparatus for performing the removal of heavy metals from water using the process outlined above.

  20. Phytochemicals Mediated Remediation of Neurotoxicity Induced by Heavy Metals

    PubMed Central

    Gupta, Vivek Kumar; Singh, Shweta; Agrawal, Anju; Siddiqi, Nikhat Jamal; Sharma, Bechan

    2015-01-01

    Almost all the environmental components including both the abiotic and biotic factors have been consistently threatened by excessive contamination of heavy metals continuously released from various sources. Different heavy metals have been reported to generate adverse effects in many ways. Heavy metals induced neurotoxicity and impairment in signalling cascade leading to cell death (apoptosis) has been indicated by several workers. On one hand, these metals are required by the cellular systems to regulate various biological functions of normal cells, while on the other their biomagnification in the cellular systems produces adverse effects. The mechanism by which the heavy metals induce neurotoxicity follows free radicals production pathway(s) specially the generation of reactive oxygen species and reactive nitrogen species. These free radicals produced in excess have been shown to create an imbalance between the oxidative and antioxidative systems leading to emergence of oxidative stress, which may cause necrosis, DNA damage, and many neurodegenerative disorders. This mini review summarizes the current knowledge available on the protective role of varied natural products isolated from different herbs/plants in imparting protection against heavy metals (cadmium, lead, arsenic, and mercury) mediated neurotoxicity. PMID:26618004

  1. Water hyacinth as indicator of heavy metal pollution the tropics

    SciTech Connect

    Gonzalez, H.; Otero, M. ); Lodenius, M. )

    1989-12-01

    The water hyacinth (Eichhornia crassipes) is a common aquatic plant in many tropical countries. Its ability absorb nutrients and other elements from the water has made it possible to use it for water purification purposes. Eichhornia, especially stems and leaves, have been successfully used as indicators of heavy metal pollution in tropical countries. The uptake of heavy metals in this plant is stronger in the roots than in the floating shoots. Metallothionein-like compounds have been found from roots of this species after cadmium exposure. The purpose of this investigation was to study the possibilities of using roots of water hyacinth as a biological indicator of metal pollution in tropical aquatic ecosystems.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  3. Heavy metal toxicity to bacteria - are the existing growth media accurate enough to determine heavy metal toxicity?

    PubMed

    Rathnayake, I V N; Megharaj, Mallavarapu; Krishnamurti, G S R; Bolan, Nanthi S; Naidu, Ravi

    2013-01-01

    A new minimal medium was formulated considering the limitations of the existing media for testing heavy metal sensitivity to bacteria. Toxicity of cadmium and copper to three bacteria was investigated in the new medium and compared with three other media commonly used to study the effect of the toxic metals. Based on speciation data arrived at using ion-selective electrodes, the available free-metal concentration in solution was highest in the MES-buffered medium. This finding was strongly supported by the estimated EC(50) values for the metals tested based on the toxicity bioassays. The free-ionic cadmium and copper concentrations in the medium provide more accurate determination of metal concentrations that affects the bacteria, than with most of other existing media. This will avoid doubts on other media and misleading conclusions relevant to the toxicity of heavy metals to bacteria and provides a better option for the study of metal-bacteria interactions.

  4. Heavy metal capture and accumulation in bioretention media.

    PubMed

    Li, Houng; Davis, Allen P

    2008-07-15

    Heavy metal capture and accumulation in bioretention media were investigated through the use of a one-dimensional filtration equation for particulate metals, advection/dispersion/adsorption transport equations for dissolved metals, and sequential extractions. Predicted spatial profiles and partitioning patterns of captured metals were compared to data derived from a bioretention cell in the District of Columbia. Zinc, lead, and copper profiles showed a high surface accumulation, significantly decreasing with the media depth. Surface street particle-enriched areas had the highest heavy metal levels, demonstrating a close relationship between capture of metals and runoff particles. Sequential extractions suggested that most captured metals were of anthropogenic origin. Soluble-exchangeable bound metals from the sequential extraction correlated well with predicted aqueous dissolved metals; the more strongly associated metal fractions correlated with modeled runoff and media particulate metals. A simple risk evaluation indicated thatlead isthe limiting metal in bioretention accumulation. On the basis of information collected in this study, a shallow bioretention cell design is suggested for systems with a focus on metal capture.

  5. Molecular Indicators of Soil Humification and Interaction with Heavy Metals

    SciTech Connect

    Fan, Teresa W.-M.; Higashi, Richard M.; Cassel, Teresa; Green, Peter; Lane, Andrew N.

    2003-03-26

    For stabilization of heavy metals at contaminated sites, interaction of soil organic matter (SOM) with heavy metal ions is critically important for long-term sustainability, a factor that is poorly understood at the molecular level. Using 13C- and 15N-labeled soil humates (HS), we investigated the turnover of five organic amendments (celluose, wheat straw, pine shavings, chitin and bone meal) in relation to heavy metal ion leaching in soil column experiments. The labeled molecular substructures in HS were examined by multinuclear 2-D NMR and pyrolysis GC-MS while the element profile in the leachates was analyzed by ICP-MS. Preliminary analysis revealed that peptidic and polysaccharidic structures were highly enriched, which suggests their microbial origin. Cd(II) leaching was significantly attenuated with humification of lignocellulosic materials. Correlation of 13C and 15N turnovers of HS substructures to metal leaching is underway.

  6. Increased Tolerance to Heavy Metals Exhibited by Swarming Bacteria

    NASA Astrophysics Data System (ADS)

    Anyan, M.; Shrout, J. D.

    2014-12-01

    Pseudomonas aeruginosa is a ubiquitous, Gram-negative bacterium that utilizes several different modes of motility to colonize surfaces, including swarming, which is the coordinated movement of cells over surfaces in groups. Swarming facilitates surface colonization and biofilm development for P. aeruginosa, and it is known that swarming behavior is influenced by changes in nutrient composition and surface moisture. To understand the fate and cycling of heavy metals in the environment, it is important to understand the interaction and toxicity of these metals upon bacteria. While previous studies have shown surface-attached bacterial biofilms to be highly resistant to heavy metal toxicity, little is known about the influence of heavy metals upon surface motile bacteria and developing biofilms. Using a combination of laboratory assays we examined differences in bacterial behavior in response to two metals, Cd and Ni. We find that surface swarming bacteria are able to grow on 4x and 2.5x more Cd and Ni, respectively, than planktonic cells (i.e., test tube cultures). P. aeruginosa was able to swarm in the presence ≤0.051mM Ni and ≤0.045mM Cd. To investigate the bioavailability of metals to bacteria growing under our examined conditions, we separated cell and supernatant fractions of P. aeruginosa cultures, and used ICP-MS techniques to measure Cd and Ni sorption. A greater percentage of Cd than Ni was sorbed by both cells and supernatant (which contains rhamnolipid, a surfactant known to sorb some metals and improve swarming). While we show that cell products such as rhamnolipid bind heavy metals (as expected) and should limit metal bioavailability, our results suggest at least one additional mechanism (as yet undetermined) that promotes cell survival during swarming in the presence of these heavy metals.

  7. Stability of alkali-metal hydrides: effects of n-type doping

    NASA Astrophysics Data System (ADS)

    Olea Amezcua, Monica Araceli; de La Peña Seaman, Omar; Rivas Silva, Juan Francisco; Heid, Rolf; Bohnen, Klaus-Peter

    Metal hydrides could be considered ideal solid-state hydrogen storage systems, they have light weight and high hydrogen volumetric densities, but the hydrogen desorption process requires excessively high temperatures due to their high stability. Efforts have been performed to improve their dehydrogenation properties, based on the introduction of defects, impurities and doping. We present a systematic study of the n-type (electronic) doping effects on the stability of two alkali-metal hydrides: Na1-xMgxH and Li1-xBexH. These systems have been studied within the framework of density functional perturbation theory, using a mixed-basis pseudopotential method and the self-consistent version of the virtual crystal approximation to model the doping. The full-phonon dispersions are analyzed for several doping content, paying special attention to the crystal stability. It is found a doping content threshold for each system, where they are close to dynamical instabilities, which are related to charge redistribution in interstitial zones. Applying the quasiharmonic approximation, the vibrational free energy, the linear thermal expansion and heat capacities are obtained for both hydrides systems and are analyzed as a function of the doping content. This work is partially supported by the VIEP-BUAP 2016 and CONACYT-México (No.221807) projects.

  8. Alkali metal pool boiler life tests for a 25 kWe advanced Stirling conversion system

    NASA Technical Reports Server (NTRS)

    Anderson, W. G.; Rosenfeld, J. H.; Noble, J.

    1991-01-01

    The overall operating temperature and efficiency of solar-powered Stirling engines can be improved by adding an alkali metal pool boiler heat transport system to supply heat more uniformly to the heater head tubes. One issue with liquid metal pool boilers is unstable boiling. Stable boiling is obtained with an enhanced boiling surface containing nucleation sites that promote continuous boiling. Over longer time periods, it is possible that the boiling behavior of the system will change. An 800-h life test was conducted to verify that pool boiling with the chosen fluid/surface combination remains stable as the system ages. The apparatus uses NaK boiling on a - 100 + 140 stainless steel sintered porous layer, with the addition of a small amount of xenon. Pool boiling remained stable to the end of life test. The pool boiler life test included a total of 82 cold starts, to simulate startup each morning, and 60 warm restarts, to simulate cloud cover transients. The behavior of the cold and warm starts showed no significant changes during the life test. In the experiments, the fluid/surface combination provided stable, high-performance boiling at the operating temperature of 700 C. Based on these experiments, a pool boiler was designed for a full-scale 25-kWe Stirling system.

  9. An extended basis set {ital ab} {ital initio} study of alkali metal cation--water clusters

    SciTech Connect

    Feller, D.; Glendening, E.D.; Woon, D.E.; Feyereisen, M.W.

    1995-09-01

    Ionic clusters comprised of a single alkali metal cation and up to eight water molecules were studied at the Hartree--Fock and correlated levels of theory using the correlation consistent sequence of basis sets. Estimates of the degree of convergence in the computed properties with respect to the complete basis set limit were facilitated by the underlying systematic manner in which the correlation consistent sets approach completeness. In favorable cases, improved property values could be obtained by fitting finite basis set results with a simple analytical expression in order to extrapolate to the complete basis set limit. The sensitivity of structures and binding energies were analyzed with regard to the inclusion of valence and core-valence correlation recovery at the MP2, MP4, and CCSD(T) levels of theory. The replacement of metal core electrons and the introduction of relativistic contributions via effective core potentials was compared to corresponding all-electron results. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  10. Elucidating the magnetic and superconducting phases in the alkali metal intercalated iron chalcogenides

    SciTech Connect

    Wang, Meng; Yi, Ming; Tian, Wei; Bourret-Courchesne, Edith; Birgeneau, Robert J.

    2016-02-29

    Here, the complex interdigitated phases have greatly frustrated attempts to document the basic features of the superconductivity in the alkali metal intercalated iron chalcogenides. Here, using elastic neutron scattering, energy-dispersive x-ray spectroscopy, and resistivity measurements, we elucidate the relations of these phases in RbxFeySe2-zSz. We find (i) the iron content is crucial in stabilizing the stripe antiferromagnetic (AF) phase with rhombic iron vacancy order (y ≈ 1.5), the block AF phase with root 5 x root 5 iron vacancy order (y ≈ 1.6), and the iron vacancy-free phase (y ≈ 2); and (ii) the iron vacancy-free superconducting phase (z = 0) evolves into an iron vacancy-free metallic phase with sulfur substitution (z > 1.5) due to the progressive decrease of the electronic correlation strength. Both the stripe AF phase and the block AF phase are Mott insulators. The iron-rich compounds (y > 1.6) undergo a first order transition from an iron vacancy disordered phase at high temperatures into the √5 x √5 iron vacancy ordered phase and the iron vacancy-free phase below Ts. Our data demonstrate that there are miscibility gaps between these three phases. The existence of the miscibility gaps in the iron content is a key to understanding the relationship between these complicated phases.

  11. Potential-modulated intercalation of alkali cations into metal hexacyanoferrate coated electrodes. 1998 annual progress report

    SciTech Connect

    Schwartz, D.T.

    1998-06-01

    'This program is studying potential-driven cation intercalation and deintercalation in metal hexacyanoferrate compounds, with the eventual goal of creating materials with high selectivity for cesium separations and long cycle lifetimes. The separation of radiocesium from other benign cations has important implications for the cost of processing a variety of cesium contaminated DOE wasteforms. This report summarizes results after nine months of work. Much of the initial efforts have been directed towards quantitatively characterizing the selectivity of nickel hexacyanoferrate derivatized electrodes for intercalating cesium preferentially over other alkali metal cations. Using energy dispersive xray spectroscopy (ex-situ, but non-destructive) and ICP analysis (ex-situ and destructive), the authors have demonstrated that the nickel hexacyanoferrate lattice has a strong preference for intercalated cesium over sodium. For example, when ions are reversibly loaded into a nickel hexacyanoferrate thin film from a solution containing 0.9999 M Na{sup +} and 0.0001 M Cs{sup +}, the film intercalates 40% as much Cs{sup +} as when loaded from pure 1 M Cs{sup +} containing electrolyte (all electrolytes use nitrates as the common anion). The authors have also shown that, contrary to the common assumptions found in the literature, a significant fraction of the thin film is not active initially. A new near infrared laser has been purchased and is being added to the Raman spectroscopy facilities to allow in-situ studies of the intercalation processes.'

  12. Elucidating the magnetic and superconducting phases in the alkali metal intercalated iron chalcogenides

    DOE PAGES

    Wang, Meng; Yi, Ming; Tian, Wei; ...

    2016-02-29

    Here, the complex interdigitated phases have greatly frustrated attempts to document the basic features of the superconductivity in the alkali metal intercalated iron chalcogenides. Here, using elastic neutron scattering, energy-dispersive x-ray spectroscopy, and resistivity measurements, we elucidate the relations of these phases in RbxFeySe2-zSz. We find (i) the iron content is crucial in stabilizing the stripe antiferromagnetic (AF) phase with rhombic iron vacancy order (y ≈ 1.5), the block AF phase with root 5 x root 5 iron vacancy order (y ≈ 1.6), and the iron vacancy-free phase (y ≈ 2); and (ii) the iron vacancy-free superconducting phase (z =more » 0) evolves into an iron vacancy-free metallic phase with sulfur substitution (z > 1.5) due to the progressive decrease of the electronic correlation strength. Both the stripe AF phase and the block AF phase are Mott insulators. The iron-rich compounds (y > 1.6) undergo a first order transition from an iron vacancy disordered phase at high temperatures into the √5 x √5 iron vacancy ordered phase and the iron vacancy-free phase below Ts. Our data demonstrate that there are miscibility gaps between these three phases. The existence of the miscibility gaps in the iron content is a key to understanding the relationship between these complicated phases.« less

  13. Synthesis, structures and stabilities of thioanisole-functionalised phosphido-borane complexes of the alkali metals.

    PubMed

    Izod, Keith; Watson, James M; Clegg, William; Harrington, Ross W

    2011-11-28

    Treatment of the secondary phosphine {(Me(3)Si)(2)CH}PH(C(6)H(4)-2-SMe) with BH(3)·SMe(2) gives the corresponding phosphine-borane {(Me(3)Si)(2)CH}PH(BH(3))(C(6)H(4)-2-SMe) (9) as a colourless solid. Deprotonation of 9 with n-BuLi, PhCH(2)Na or PhCH(2)K proceeds cleanly to give the corresponding alkali metal complexes [[{(Me(3)Si)(2)CH}P(BH(3))(C(6)H(4)-2-SMe)]ML](n) [ML = Li(THF), n = 2 (10); ML = Na(tmeda), n = ∞ (11); ML = K(pmdeta), n = 2 (12)] as yellow/orange crystalline solids. X-ray crystallography reveals that the phosphido-borane ligands bind the metal centres through their sulfur and phosphorus atoms and through the hydrogen atoms of the BH(3) group in each case, leading to dimeric or polymeric structures. Compounds 10-12 are stable towards both heat and ambient light; however, on heating in toluene solution in the presence of 10, traces of free phosphine-borane 9 are slowly converted to the free phosphine {(Me(3)Si)(2)CH}PH(C(6)H(4)-2-SMe) (5) with concomitant formation of the corresponding phosphido-bis(borane) complex [{(Me(3)Si)(2)CH}P(BH(3))(2)(C(6)H(4)-2-SMe)]Li (14).

  14. Heavy metals in the volcanic environment and thyroid cancer.

    PubMed

    Vigneri, R; Malandrino, P; Gianì, F; Russo, M; Vigneri, P

    2016-10-26

    In the last two decades thyroid cancer incidence has increased worldwide more than any other cancer. Overdiagnosis of subclinical microcarcinomas has certainly contributed to this increase but many evidences indicate that a true increase, possibly due to environmental factors, has also occurred. Thyroid cancer incidence is markedly increased in volcanic areas. Thus, the volcanic environment is a good model to investigate the possible factors favoring thyroid cancer. In the volcanic area of Mt. Etna in Sicily, as well as in other volcanic areas, a non-anthropogenic pollution with heavy metals has been documented, a consequence of gas, ash and lava emission. Soil, water and atmosphere contamination, via the food chain, biocontaminate the residents as documented by high levels in the urines and the scalp hair compared to individuals living in adjacent non-volcanic areas. Trace amounts of metals are essential nutrients but, at higher concentrations, can be toxic for living cells. Metals can behave both as endocrine disruptors, perturbing the hormonal system, and as carcinogens, promoting malignant transformation. Similarly to other carcinogens, the transforming effect of heavy metals is higher in developing organisms as the fetus (contaminated via the mother) and individuals in early childhood. In the last decades environment metal pollution has greatly increased in industrialized countries. Although still within the "normal" limits for each single metal the hormesis effect (heavy metal activity at very low concentration because of biphasic, non linear cell response) and the possible potentiation effect resulting from the mixture of different metals acting synergistically can explain cell damage at very low concentrations. The effect of metals on the human thyroid is poorly studied: for some heavy metals no data are available. The scarce studies that have been performed mainly focus on metal effect as thyroid endocrine disruptors. The metal concentration in tissues has

  15. Heavy metals in composts of separated municipal wastes

    SciTech Connect

    Liao, W.P.; Huang, W.C.; Fan, W.H.; Hsu, C.C.

    1997-12-31

    This study is to examine the influence of the metal components on the contents of heavy metals in composts of Municipal Solid Wastes (MSW). Fresh MSW used in composting was obtained from the city landfill of Taichung in Taiwan. Compost 1 was from as-collected MSW; Compost 2 was from degradable fraction in MSW; Compost 3 was from MSW without metal. The results show that the total concentration of zinc is the highest among the five heavy metals examined. Paper wastes are main sources of lead and copper with average concentrations of 18.53 mg/kg and 26.92 mg/kg of compost on dry weight. The contents of nickel and cadmium are relatively low. The total concentrations of the five heavy metals in composts increase by typical ratios between 1.72 and 2.58 for Composts 2 and 3, but 3.16 to 4.69 for Compost 1. The increase of concentration around a ratio of 2.0 is due to the loss of degraded organic matter. For the ratios above 2.0, fractions of some heavy metals have corroded from the surfaces of metal components into the Compost 1 in the early phase of acidic fermentation.

  16. Heavy metal bioaccumulation and toxicity with special reference to microalgae

    NASA Astrophysics Data System (ADS)

    Arunakumara, K. K. I. U.; Zhang, Xuecheng

    2008-02-01

    The bioaccumulation and toxicity of heavy metals were reviewed with special reference to microalgae, the key component of the food web in aquatic ecosystems. Heavy metals enter algal cells either by means of active transport or by endocytosis through chelating proteins and affect various physiological and biochemical processes of the algae. The toxicity primarily results from their binding to the sulphydryl groups in proteins or disrupting protein structure or displacing essential elements. Metals can break the oxidative balance of the algae, inducing antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and ascorbate peroxidase (APX). The amount of oxidized proteins and lipids in the algal cells thus indicates the severity of the stress. Algal tolerance to heavy metal is highly dependent upon the defense response against the probable oxidative damages. Production of binding factors and proteins, exclusion of metals from cells by ion-selective transporters and excretion or compartmentalization have been suggested with regard to reducing heavy metal toxicity. However, a comprehensive description on the mechanisms underlining metal toxicity of microalgae and gaining tolerance is yet to be elaborated.

  17. A Simple Model for Fine Structure Transitions in Alkali-Metal Noble-Gas Collisions

    DTIC Science & Technology

    2015-03-01

    fine- structure transition rates of the alkali atoms . The integration of this integral is primarily performed nu- merically, using an adaptive Romberg...Previous work on the fine structure transitions of alkali atoms as they collide with noble gas atoms includes a full quantum mechanical calculation of...adiabaticity in alkali atom fine structure mixing”. SPIE LASE, 896207–896207. International Society for Optics and Photonics, 2014. 4. Griffiths, David J

  18. Perspectives in endocrine toxicity of heavy metals--a review.

    PubMed

    Rana, S V S

    2014-07-01

    An attempt has been made to review the endocrine/hormonal implications of a few environmentally significant metals, viz, lead, mercury, cadmium, copper, arsenic and nickel, in man and animals. Special emphasis has been given to the adrenals, thyroid, testis, ovary and pancreas. Toxic metals can cause structural and functional changes in the adrenal glands. Their effects on steroidogenesis have been reviewed. It has been reported that thyroid hormone kinetics are affected by a number of metallic compounds. Occupational exposure to a few of these metals can cause testicular injury and sex hormone disturbances. Protective effects of a few antioxidants on their reproductive toxicity have also been discussed. Information gathered on female reproductive toxicity of heavy metals shows that exposure to these metals can lead to disturbances in reproductive performance in exposed subjects. Certain metals can cause injury to the endocrine pancreas. Exposure to them can cause diabetes mellitus and disturb insulin homeostasis. The need to develop molecular markers of endocrine toxicity of heavy metals has been suggested. Overall information described in this review is expected to be helpful in planning future studies on endocrine toxicity of heavy metals.

  19. Implications of soil pollution with heavy metals for public health

    NASA Astrophysics Data System (ADS)

    Juozulynas, Algirdas; Jurgelėnas, Antanas; Butkienė, Birutė; Greičiūtė, Kristina; Savičiūtė, Rasa

    2008-01-01

    Soil of military grounds is often polluted with heavy metals. Their concentrations may be dosens of times higher in polluted regions. The affected soils are permeable, so the pollutions can get into water and spread to the environment. Into human and animal organisms they can get with food and water. Heavy metals are very dangerous for people's health, and we must know their accumulation places, intensity of scatter and integral risk for health. The purpose of this work was to establish links between zones polluted with heavy metals and morbidity caused by pollution with heavy metals. The morbidity caused by heavy metals (Pb, Cu, Zn, Ca and other) in the polluted regions is 1.4-1.5 times higher for adults and teenagers and 1.5-3.9 times higher for children aged under 14 years than the mean morbidity of the same diseases in Lithuania. Hypothetically, it is possible to prognosticate that this problem will grow in future because the ratio of the newly registered and the existing cases of morbidity for children aged under 14 years is 1.3-1.5 times higher than for adults.

  20. New trends in removing heavy metals from wastewater.

    PubMed

    Zhao, Meihua; Xu, Ying; Zhang, Chaosheng; Rong, Hongwei; Zeng, Guangming

    2016-08-01

    With the development of researches, the treatments of wastewater have reached a certain level. Whereas, heavy metals in wastewater cause special concern in recent times due to their recalcitrance and persistence in the environment. Therefore, it is important to get rid of the heavy metals in wastewater. The previous studies have provided many alternative processes in removing heavy metals from wastewater. This paper reviews the recent developments and various methods for the removal of heavy metals from wastewater. It also evaluates the advantages and limitations in application of these techniques. A particular focus is given to innovative removal processes including adsorption on abiological adsorbents, biosorption, and photocatalysis. Because these processes have leaded the new trends and attracted more and more researches in removing heavy metals from wastewater due to their high efficency, pluripotency and availability in a copious amount. In general, the applicability, characteristic of wastewater, cost-effectiveness, and plant simplicity are the key factors in selecting the most suitable method for the contaminated wastewater.