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1

Separation of palladium(II) from mixtures of non-ferrous metal ions by solvent extraction

Radzyminska-Lenarcik E., Witt K.

Challenges of Modern Technology

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2016

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Vol. 7, no. 1

17-22

EN

The possibility of Pd(II) ions separation from mixtures of Co(II), Ni(II), Cu(II) and Pd(II) ions by solvent extraction was studied, using 1-hexyl-2methylimidazole in chloroform as the extractant. The initial concentration of each ion was 10 mM. The tests were carried out at a temperature of 25°C, at a constant strength of the aqueous solution of I = 0.5, as maintained by the KCl solution. It was demonstrated that differences in the stability and structure of their coordination sphere as well as solubility of complexes with the extractant could be used for separating the Co(II), Ni(II), Cu(II) and Pd(II) ions by solvent extraction. Pd(II), which forms flat-square complexes in the solutions, passes easily into the organic phase and is easier separated from the mixture of Co(II), Ni(II), Cu(II) ions, which form octahedral or tetrahedral complexes. Extraction percentages were calculated. For the respective metals, their values increase for increasing concentrations of the extractant in the aqueous phase. The extraction percentage decreases in the following order: Pd(II) > Cu(II) > Co(II) > Ni(II). In the case of the quaternary mixture, the highest extraction percentage for Pd(II) (70%) was obtained at a pH=7.33. Separation coefficients were also calculated. The highest separation coefficients were obtained for the system: Pd(II)/Ni(II), Pd(II)/Co(II); at a pH of 5.4 for an aqueous solution, their values are 13.3 and 7.7, respectively.

2

The use of the steric effect of the carrier molecule in the polymer inclusion membranes for the separation of cobalt(II), nickel(II), copper(II), and zinc(II) ions

Radzyminska-Lenarcik E., Ulewicz M.

Polish Journal of Chemical Technology

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2015

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Vol. 17, nr 2

51--56

EN

In this study, palladium-modified nickel foam substrate was applied to examine ethanol oxidation reaction (EOR) in 0.1 The transport of cobalt(II), nickel(II), copper(II), and zinc(II) ions from chloride solutions across polymer inclusion membranes (PIMs), which 1-heptylimidazole (1̲) or 1-heptyl-2-methylimidazole (2̲) or 1-heptyl-4-methylimidazole (3̲) as the ion carrier was reported. The steric effect for carriers 2̲&enspand 3̲&enspdecreases the transport of all ions except Cu(II). The initial fluxes of metal ions transport across PIMs with the 1̲- 2̲&enspdecrease in the sequence: Cu(II) > Zn(II) > Co(II) > Ni(II), whereas for 3 they were Cu(II) > Zn(II) > Ni(II) > Co(II). The highest recovery values were obtained for Cu(II), this being 99 and 85% for carrier 1̲&enspand 2̲, respectively. In both membranes the degree of deposition of the Zn(II) ions was comparable. Zn(II), Co(II) and Cd(II) ions, which form complexes with coordination numbers 4 and 6, are more easily recovered with the use of carriers 2̲&enspand 3̲. Ni(II) ions, which form complexes with coordination number 6 only, practically remain in the feeding phase. PIMs with alkylimidazoles were characterized by non-contact atomic force microscopy.

3

Nickel-cobalt separation by solvent extraction method

Radzyminska-Lenarcik E., Wasilewska A.

Challenges of Modern Technology

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2015

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Vol. 6, no. 3

20--23

EN

Separation of cobalt(II), and nickel(II) ions from nitrate solutions using liquid-liqiud extraction process was reported. The measurements were run at 25oC and at fixed ionic strength equal to 0.5 (KNO3,HNO3). Initial concentrations of Co(II) and Ni(II) nitric acid in the aqueous phase were constant (0.01 M and 0.15 M, respectively). Both 1-hexylimidazole (1), and 1-hexyl-2-methylimidazole (2), both in dichloromethane were used as extractants. Their concentrations in organic phase were varied from 0.01 to 0.25 M. Cobalt(II) in an aqueous solution forms both tetrahedral and octahedral complexes. Nickel(II) forms only a six-coordinate complexes. These general differences help to provide the basis for the various separation processes currently used for cobalt-nickel separation. The steric effect for extractant 2 facilitates the extraction of tetrahedral Co(II) complexes. Extraction percent (%E) of cobalt(II) and nickel(II) in the systems studied were calculated. The percentage extraction increases for increasing values of pH of aqueous phase and is the highest for pH = 7.2. In the aqueous phase, of which the pH = 7.2, there remain 75%Ni(II) and 40% Co(II) for extractant 1 and the respective values for extractant 2 are 85% Ni(II) and 20% Co(II). The steric effect increases selectivity coefficients Co(II)/Ni(II). The highest selectivity coefficients for both extractants were obtained at a pH of aqueous phase = 6.2; their values were 5 and 8.9 for extractants 1 and 2, respectively.

4

The use of 1-alkylimidzoles for selective separation of zinc ions in the transport process across a polymeric inclusion membrane

Radzyminska-Lenarcik E., Ulewicz M.

Physicochemical Problems of Mineral Processing

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2014

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Vol. 50, iss. 1

131--142

EN

The transport of Zn(II) ions from different aqueous nitrate(V) source feeding phases (cMe = 0.001 mol/dm3, pH 6.0) across polymer inclusion membranes (PIMs) doped with 1-alkylimidazole as an ion carrier was reported. Alkyl substituents in position 1 of imidazole ring have an effect on hydrophobic properties of the carriers and the initial flux of the transported metal ions. The membranes were characterized by an atomic force microscopy (AFM). The results show that the Zn(II) ions could effectively be separated from other transition metal cations such as Co(II) and Ni(II) from different equimolar ion mixtures. Also, the thermal stability of PIM doped with 1-decylimidazole was studied in replicate experiments. The highest separation coefficients for the Zn(II)/Co(II) and Zn(II)/Ni(II) systems, equal to 9.4 and 11.9 were recorded for the equimolar Zn(II)-Co(II)-Ni(II) mixture for 1-hexylimidazole as a carrier, while using 1-decylimidazole resulted in the highest values of initial flux of the Zn(II) ions transport across the polymeric membrane.