Equilibrium and mechanism of cobalt(II) extraction from chloride solution by hydrophobic 2-pyridineketoxime

Preparation of new polysulfone capsules containing Cyanex 272 and their properties for Co(II) removal from aqueous solution

“…Up to now, the various techniques, such as adsorption [2][3][4][5][6][7], facilitated transport through bulk liquid membrane [8], supported liquid membrane [9,10], emulsion liquid membrane [11,12] and liquid-liquid extraction (LLE) [13,14] have been used for recovery or removal of Co(II) from aqueous solutions.…”

Equilibrium studies of cobalt(II) extraction with 2-pyridineketoxime from mixed sulphate/chloride solution

“…It has been observed that in all studied range of cobalt(II) ions concentration, the amount of the extracted metal ions increases linearly even for the solution containing more than 0.1 mol/dm 3 Co 2+ . This effect may be attributed to the coordination of cobalt-chloride species, which have a tendency to aggregation especially at higher concentrations of chloride solutions [19]. The molecular aggregate formed an association complex.…”

“…Our recent studies have indicated that 1-(2-pyridyl)tridecan-1-one oxime forms stable complexes with cobalt(II) ions especially in the presence of chloride ions and an effective re-extraction is possible at reducing conditions [19]. This knowledge enables to assume a comparably high stability of the complexes created in the studied chloride/sulphate mixture, therefore a stripping test has been carried out using an aqueous solution of HCl (10, 20 and 30 %) at 30 °C, at phase ratios of 1 and with addition or without a metallic reductant in either an inert atmosphere or air.…”

“…Especially, oxime of 1-(2-pyridyl)tridecan-1-one has shown good extraction abilities towards all studied metals copper(II), zinc(II), cadmium(II) and iron(III) ions from chloride and chloride/ammonia solutions [9–15], as well as copper(II) and nickel(II) ions from solutions containing both chloride and sulphate salts [16, 17]. Recent studies have also indicated the possibility to apply the oxime of 1-(2-pyridyl)tridecan-1-one for a separation of cobalt from nickel sulphate solution [18], but so far, the most efficient extraction of cobalt(II) ions using this oxime has been achieved only from the chloride/nitrate solution [19]. It has been assumed that the addition of chloride ions to cobalt sulphate solution should improve the extraction efficiency by oxime of 1-(2-pyridyl)tridecan-1-one, and also change the complexation mechanism.…”

Cobalt Extraction from Sulfate/Chloride Media with Trioctyl(alkyl)phosphonium Chloride Ionic Liquids

“…Extraction and separation of Pt­(IV), Pd­(II), Ru­(III), and Rh­(III) with imidazolium-based ILs were evaluated . The mostly studied ILs for the extraction of metal ions are those of imidazolium derivatives with different extractants, ligands, and metal chelators. − ,− However, they present two great disadvantages that cannot be overcome in metal extraction. First, these are hydrolyzed in an acid medium. , Second, many extraction mechanisms are cation exchange , or anion exchange, , which indicates the release of 1-alkyl-3-methyl-imidazolium cations, C n mim + , and bis­(trifluoromethanesulfonyl)­imide anions, Tf 2 N – , to the aqueous phase .…”