Partitioning cobalt

Chabot, N. L., Draper, D. S. and Agee, . B. (2005) Conditions of core formation in the Earth constraints from nickel and cobalt partitioning. Geochimica et Cosmochimica Acta, 69,2141-2151. 

The first identified complexes of unsubstituted thiazole were described by Erlenmeyer and Schmid (461) they were obtained by dissolution in absolute alcohol of both thiazole and an anhydrous cobalt(II) salt (Table 1-62). Heating the a-CoCri 2Th complex in chloroform gives the 0 isomer, which on standirtg at room temperature reverses back to the a form. According to Hant2sch (462), these isomers correspond to a cis-trans isomerism. Several complexes of 2,2 -(183) and 4,4 -dithiazolyl (184) were also prepared and found similar to pyridyl analogs (185) (Table 1-63). Zn(II), Fe(II), Co(II), Ni(II) and Cu(II) chelates of 2.4-/>is(2-pyridyl)thiazole (186) and (2-pyridylamino)-4-(2-pyridy])thiazole (187) have been investigated. The formation constants for species MLr, and ML -" (L = 186 or 187) have been calculated from data obtained by potentiometric, spectrophotometric, and partition techniques. 

Chymotrypsin, 170,171, 172, 173 Classical partition functions, 42,44,77 Classical trajectories, 78, 81 Cobalt, as cofactor for carboxypeptidase A, 204-205. See also Enzyme cofactors Condensed-phase reactions, 42-46, 215 Configuration interaction treatment, 14,30 Conformational analysis, 111-117,209 Conjugated gradient methods, 115-116. See also Energy minimization methods Consistent force field approach, 113 Coulomb integrals, 16, 27 Coulomb interactions, in macromolecules, 109, 123-126... 

Figure 11.8 Formation of ordered nanoparticles of metal from diblock copolymer micelles, (a) Diblock copolymer (b) metal salt partition to centres of the polymer micelles (c) deposition of micelles at a surface (d) micelle removal and reduction of oxide to metal, (e) AFM image of carbon nanotubes and cobalt catalyst nanoparticles after growth (height scale, 5 nm scan size, lxl pm). [Part (e) reproduced from Ref. 47].

Coprecipitation is a partitioning process whereby toxic heavy metals precipitate from the aqueous phase even if the equilibrium solubility has not been exceeded. This process occurs when heavy metals are incorporated into the structure of silicon, aluminum, and iron oxides when these latter compounds precipitate out of solution. Iron hydroxide collects more toxic heavy metals (chromium, nickel, arsenic, selenium, cadmium, and thorium) during precipitation than aluminum hydroxide.38 Coprecipitation is considered to effectively remove trace amounts of lead and chromium from solution in injected wastes at New Johnsonville, Tennessee.39 Coprecipitation with carbonate minerals may be an important mechanism for dealing with cobalt, lead, zinc, and cadmium. 

The most widely used technique for the separation of large quantities of radioactive material is that of solvent extraction. The principle of the method is that ideally the partition coefficient of a compound between two solvents does not depend on concentration in a given set of conditions. This was shown in an early paper of Graham and Sea-borg (35) who demonstrated that the partition coefficients of gallium and cobalt chlorides between ether and aqueous hydrochloric acid were the same for concentrations of lCTli molar (i. e. no added carrier) as for 1-6xl0 s molar. 

Lindstrom D. I and Weill D. F. (1978). Partitioning of transition metals between diopside and coexisting silicate liquids, I Nickel, cobalt, and manganese. Geochim. Cosmochim. Acta, 42 801-816. 

Shishkin, D.N., Galkin, B.Ya.,Fedorov,Yu.S.,Zilberman, B.Ya.,Shmidt,O.V.Partitioning of high-level waste with an extractant based on chlorinated cobalt dicarbollide and dibu-tylphosphoric acid zirconium salt. Radiochemistry (2003), 45 (6), 577-580. 

Tachimori, S., Ito, Y. 1979. Radiation damage of organic extractant in partitioning of high-level liquid waste, (I) Radiolysis of di(2-ethylhexyl)phosphoric acid by irradiation with cobalt-60 gamma rays. J. Nucl. Sci. Technol. 16(1) 49-56. 

Glassley, W. E. Piper, D. Z. (1978) Cobalt and scandium partitioning versus iron content for crystalline phase in ultramafic nodules. Earth Planet. Sci. Lett., 39, 173-8. 

The partition coefficients for these chelates have been determined by static methods and found to be as follows beryllium, 4.4 chromium, 16.1 ruthenium, 23.2 and cobalt, 33.5. 

The results given In Figure 15 are for two aqueous phases, one of which had a pH of 8.5 and the other a pH of 11.1, and both of which contained the same concentration of sodium dodecyl sulphate. Two points are Immediately apparent from these results (a) the normal partition law is obeyed, at least over the range of concentrations investigated, and (b) the partition coefficient Is Independent of the pH of the aqueous phase. The first of these observations implies that cobalt (III) acetylacetonate has the same molecular complexity In both the aqueous and the butadiene phases. These results also show that the initiator partitions in such a way that its concentration in the butadiene phase is considerably greater than that in the aqueous phase in fact, the partition coefficient for this particular aqueous phase at 50°C Is approximately 6.54. 

Orthopyroxene partitions nickel, cobalt, and manganese less than olivine and there are no clear correlations amongst these elements. Although low in abundance, orthopyroxene can be a significant reservoir for the trivalent cations vanadium, scandium plus tetravalent titanium, due to its high modal abundance, especially in depleted xenoliths with little or... 

Principal experimental data on spinel-melt partitioning are those of Nielsen et al. (1994) for scandium, nickel, vanadium, zirconium, hafnium, niobium, tantalum, uranium, and thorium and Horn et al. (1994) for scandium, vanadium, gallium, zinc, cobalt, zirconium, hafnium, niobium, and tantalum. These are supplemented by data for hydrous melts by Nielsen and Beard (2000). 

Figure 4 Metal/magnesiowUstite partition coefficients for nickel, cobalt, manganese, chromium, and vanadium at 9 GPa, and the effect of temperature (pressure 9 GPa). Partition coefficients are calculated relative to iron, according to the exchange equihhrium, M - - FeO = Fe + MO. Horizontal lines at right side of the diagram indicate the values of ATd that would he required for an equihhrium explanation for these hve elements in the terrestrial mantle (source Gessmann and Ruhie (1998) these authors favor a high-temperature scenario to attain these concentrations in the mantle).

Figure 6 Effect of silicate melt composition on metal/silicate partition coefficients for cobalt ( ), gallium (+), tungsten (o), and phosphorus ( ) (Jaeger and Drake, 2000 Pak and Fruehan, 1986). NBO/t is calculated according to Mysen (1991) and corresponds to basalt values of 1, komatiite —1.7, and peridotite —2.8. In general, high-valence elements such as tungsten and phosphorus are affected more strongly than lower valence elements such as cobalt (or nickel).

Figure 9 Comparison of In D (calculated) versus In D (measured) with data for cobalt n = 207) and tungsten n = 109), and using oxide-component-based compositional terms. Open symbols are 0.1 MPa experiments, and solid symbols are higher-pressure experiments. Dashed lines are 2cr errors on the regressions. The number of experiments used in the regression is indicated as n. M/LS refers to metal/liquid silicate for the partition coefficients, and includes experiments that have solid metal or liquid metal (source Righter and Drake, 1999).

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