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Liquid–liquid extraction of metal ions without use of organic solvent
- Source :
-
Separation & Purification Technology . Sep2008, Vol. 62 Issue 3, p687-693. 7p. - Publication Year :
- 2008
-
Abstract
- Abstract: The extraction behavior of the ions Ni(II), Fe(III), Cd(II), Co(II), Zn(II) and Cu(II) was studied as a function of the amount of extractant added, in aqueous two-phase systems (ATPS) formed mostly by water and without the use of any organic solvent. The others ATPS components were a triblock copolymer (L35) and Na2SO4. Two types of water-soluble extractants (thiocyanate, iodide) and one slightly water-soluble extractant [1-nitroso-2-naphthol (1N2N)] were studied separately. It must be emphasized that this is the first study using a slightly water-soluble complexant for the metallic partition in ATPS, which was not a restrictive factor to the technique as believed. The extraction to the L35 rich-phase of all suited metal ions was insignificant without extractant addition. However, the effectiveness of SCN− in extracting metal ions in the system could be observed in the following sequence: Zn(II)≅Co(II)>Cd(II)>Cu(II)>Fe(III)>Ni(II), with Zn(II), Co(II) and Cd(II) quantitatively extracted and Cu(II) enriched by almost 80%. In the case of the I− extractant, all metal ions, except Cd(II) and Cu(II), remained in the salt-rich phase, providing favorable conditions to the selective separation of Ni(II), Co(II) and Fe(III) ions from Cd(II). The results show that, at pH 7.2, L35/Na2SO4/H2O ATPS can be used with 1N2N as extractant, to separate Co(II) from a complex mixture containing Fe(III), Zn(II) and Cd(II). It was observed, when using 1N2N, that a significant increase in metal extraction takes place as the pH increases, except for Cd(II) and Zn(II). [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 13835866
- Volume :
- 62
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- Separation & Purification Technology
- Publication Type :
- Academic Journal
- Accession number :
- 33530876
- Full Text :
- https://doi.org/10.1016/j.seppur.2008.03.032