Cooperative adsorption of critical metal ions using archaeal poly-γ-glutamate

To guarantee the supply of critical elements in the future, the development of new technologies is essential. Siderophores have high potential in the recovery and recycling of valuable metals due to their metal-chelating properties. Using the Chrome azurol S assay, 75 bacterial strains were screened to obtain a high-yield siderophore with the ability to complex valuable critical metal ions. The siderophore production of the four selected strains Nocardioides simplex 3E, Pseudomonas chlororaphis DSM 50083, Variovorax paradoxus EPS, and Rhodococcus erythropolis B7g was optimized, resulting in significantly increased siderophore production of N. simplex and R. erythropolis. Produced siderophore amounts and velocities were highly dependent on the carbon source. The genomes of N. simplex and P. chlororaphis were sequenced. Bioinformatical analyses revealed the occurrence of an achromobactin and a pyoverdine gene cluster in P. chlororaphis, a heterobactin and a requichelin gene cluster in R. erythropolis, and a desferrioxamine gene cluster in N. simplex. Finally, the results of the previous metal-binding screening were validated by a proof-of-concept development for the recovery of metal ions from aqueous solutions utilizing C18 columns functionalized with siderophores. We demonstrated the recovery of the critical metal ions V(III), Ga(III), and In(III) from mixed metal solutions with immobilized siderophores of N. simplex and R. erythropolis.

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Separation and recovery of critical metal ions using ionic liquids

Advances in Manufacturing ◽

10.1007/s40436-015-0132-3 ◽

2016 ◽

Vol 4 (1) ◽

pp. 33-46 ◽

Cited By ~ 38

Author(s):

Terence Makanyire ◽

Sergio Sanchez-Segado ◽

Animesh Jha

Keyword(s):

Ionic Liquids ◽

Metal Ions ◽

Critical Metal

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HREM Study of electron-induced surface radiation damage in ReO3

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087495 ◽

1991 ◽

Vol 49 ◽

pp. 636-637

Author(s):

R. Ai ◽

H.-J. Fan ◽

L. D. Marks

Keyword(s):

Transition Metal ◽

Metal Ions ◽

Metal Oxides ◽

Electron Irradiation ◽

Transition Metal Oxides ◽

Carbon Film ◽

Transition Metal Ions ◽

Surface Radiation ◽

Valence Transition ◽

Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

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ELNES of Iron Compounds

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133734 ◽

1990 ◽

Vol 48 (2) ◽

pp. 28-29

Author(s):

Hiroki Kurata ◽

Kazuhiro Nagai ◽

Seiji Isoda ◽

Takashi Kobayashi

Keyword(s):

Energy Loss ◽

Metal Ions ◽

Energy Resolution ◽

Transition Metal Oxides ◽

Local Symmetry ◽

Iron Compounds ◽

Fine Structures ◽

Electron Energy Loss ◽

Fe Ions ◽

Electron Energy Loss Spectra

Electron energy loss spectra of transition metal oxides, which show various fine structures in inner shell edges, have been extensively studied. These structures and their positions are related to the oxidation state of metal ions. In this sence an influence of anions coordinated with the metal ions is very interesting. In the present work, we have investigated the energy loss near-edge structures (ELNES) of some iron compounds, i.e. oxides, chlorides, fluorides and potassium cyanides. In these compounds, Fe ions (Fe2+ or Fe3+) are octahedrally surrounded by six ligand anions and this means that the local symmetry around each iron is almost isotropic.EELS spectra were obtained using a JEM-2000FX with a Gatan Model-666 PEELS. The energy resolution was about leV which was mainly due to the energy spread of LaB6 -filament. The threshole energies of each edges were measured using a voltage scan module which was calibrated by setting the Ni L3 peak in NiO to an energy value of 853 eV.

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