Cobalt/ions/salts adsorption

The earliest investigation of the exchange reaction between the aquated ions of Co(III) and Co(II) was carried out by Hoshowsky et al., using the isotopic method ( Co). When sulphate salts ( 10 M) were employed, complete exchange was observed between the two oxidation states of cobalt, in a time of less than two min. Two separation methods were employed (a) adsorption on an alumina column, and (b) precipitation of the Co(III) as the cobaltinitrite. 

Busch and Bailar1 obtained optically active solutions of one of the enantiomers of the ethylenediaminetetraacetato-cobaltate(III) ion by selective adsorption on optically active quartz and by fractional crystallization of the strychnine salt. More recently Dwyer, Gyarfas, and Mellor2 reported the complete resolution using d and Z-tris(ethylenediamine) cobalt(III) chloride. Precipitation of the diastereoisomers was effected by addition of ethanol to the aqueous solution. The volume of ethanol used was critical and often merely the potassium salt separated. 

Qiu et al. [22] have demonstrated a technique for removal of Lead, Copper, Nickel, Cobalt, and Zinc from water by application of a Cancrinite type zeolite synthesized from fly ash, by employing molten salt method. The degree of heavy metal adsorption has been reported to vary with the type of ion exchange... 

The first step on the cobalt wave ("prewave ") corresponds to discharge of Co (II) from its complex with cysteine. The height of this wave is limited by the formation rate of complexes between adsorbed cysteine anions and Co (II) ions in the layer adjacent to the electrode (henceforth written as [CoJs). Under these conditions cysteine is clearly present in excess with respect to [Co]. Reduction of the complex Co (ID ions (compared with the free ions) evidently arises from increase in their concentration near the electrode owing to adsorption of the complexes. The decrease in the height of this surface kinetic wave with increase in ionic strength is due both to a reduction in the rate constant of the ionic reaction (salt effect) and to a decrease in [Co]5 resulting from a decrease in the absolute value... 

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