Neodymium/ ions/salts

The functionalized membranes were tested in ion transport experiments to evaluate the effect of type and level of functionalization8. The membranes were contacted on one side with a feed solution containing 1 mM concentrations of sodium, zinc, ferric and/or neodymium nitrate salts. The receiving solution in contact with the other side of the... 

The element may be obtained by separating neodymium salts from other rare earths by ion-exchange or solvent extraction techniques, and by reducing anhydrous halides such as NdFs with calcium metal. Other separation techniques are possible. 

Substrates of COMT include xenobiotics catechols, catecholamines, and catechol estrogens. Three functional classes of chemicals are known to inhibit COMT. S-Adenosyl-I-homocysteine (SAH) is a potent inhibitor of COMT as well as the other SAM-dependent methyltransferases. Inhibition results from SAH binding to the SAM binding site on the enzyme. Certain divalent ions such as Ca+2 and trivalent metal ions such as the salts of lanthanides, neodymium, and europium are excellent inhibitors of COMT. A number of catechol-type substrates such as pyrogallol, fla-vonoids, pyrones, pyridenes, hydroxyquiolines, 3-mercaptotyramine, and tropolones are irreversible inhibitors of COMT. 

In most of these systems there is clear evidence for the formation of the reduced ion For example, in NdX2 salts this is on the basis of magnetic studies (3J), and with the praseodymium chloride and bromide phases, from qualitative resistivity measurements and their structural relationships to the neodymium chlorides according to x-ray data. Cryo-scopic data for all the systems listed are also consistent with the formation of a as opposed to solute in dilute solution in MX3 (3, 7). 

In their use as catalyst components, rare earth Y zeolites are freauently prepared by ion exchange with commercial rare earth salt solutions. Such commercial salts are mixtures of different rare earths, in which the major components are lanthanum, cerium, praseodymium and neodymium (5). These rare earth elements therefore play a major role in determining the physico-chemical characteristics and stability of Y zeolites that are used in many commercial catalysts. 

The commercially important samarium-containing minerals are treated with concentrated sulfuric acid or, in the case of monazite, with a solution of sodium hydroxide (73%) at approximately 40°C (104°E) and under pressure. The element is separated from the solutions via solvent extraction or ion exchange. Sm salts are weakly yellow and may exhibit ion emission. Sm ions show luminescence and are sometimes used to generate lasers. Samarium is used in the manufacture of headphones and tape drivers, see ALSO Cerium Dysprosium Erbium Europium Gadolinium Holmium Lanthanum Lutetium Neodymium Praseodymium Promethium Terbium Ytterbium. 

Different, more specific, separation techniques were developed, each one having its special characteristics. It could be separation of other double salts - nitrates, oxalates - composed of a RE metal ion and another cation present in the solution, for example K+, Na+, NH or Mg. Double ammonium nitrate may be used for removal of lanthanum and the separation of neodymium from praseodymium. Members within the cerium group may be separated using double manganese nitrates, while elements in the yttrium group are separated using the differences in solubihty of their bromates. Auer von Welsbach did much work with RE-ammonium oxalate systems. Charles James in the USA developed an effective technique with RE-magne-sium double salts. 

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