The Factors Effect of IIIA (Ga3+, In3+, Tl3+) Extraction by Crown Ether (18C6)

H. Jasim, Hadi

	The Factors Effect of IIIA (Ga3+, In3+, Tl3+) Extraction by Crown Ether (18C6)
Al-Mustansiriyah Journal of Science
Article 1, Volume 22, Issue 1, 2011, Pages 95-102
Author
Hadi H. Jasim
Abstract
There are many factors effecting on the group IIIA ions extraction by the macro cyclic (crown ether 18C6): solvent effect, the pH range, ionic radius, the crown ether structure or the cavity size and the anion size. The 1:1:3 complex (Metal : Ligand : Anion) is the most stable, when the ionic radius of the cation fits the size of the crown ether (18C6) cavity, otherwise, the stability of the complex is poorer and the extraction decreases, if the relative size of (18C6) cavity was very different from the ionic of the metal ion, then the distribution coefficient (KD) and extraction percentage (E%) decrease, or the solvent effect, the relative efficiencies of the extraction of IIIA (Ga3+,nIn3+, Tl3+) observed depend on the number of carbon atoms in the solvent, CH3OH,CH3CH2OH, CH3CH2CH2OH. pH effect when the concentration of solution is (0.25M) and the temperature 27oC, KD and (E%) values increase when pH between (1-3.5) for Ga3+ extraction and between pH values (1-4) for In3+ and Tl3+ extraction, if the pH value more than 4 the extraction of metal ions decreases. The greatest extraction for IIIA ions follow the sequence : Tl3+>In3+>Ga3+ depend on the radius of the ions. The extraction increase when the size of the counter ion was large and the extraction efficiency was found to follow the sequence I->OH->Br->Cl- under the same conditions.

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