Abstract: The characteristic behaviour and mechanism of extraction of iron (Ⅲ) by 1-oetylnonylamine from aqueous sulfate medium were investigated, The extraction ability of this primary amine bearing secondary alkyl group was enhanced with increasing pH of the aqueous solu- tion. The extraction reaction was proved to be an endothermic process with AH value of 30.67 kJ/mol. K and 44.77 kJ/mol. K at pH 1.0 and 2.0 respectively. The extracted species are usually composed of a mixture of complexes depending on the degree of association of amine salts. The composition of the complex formed by successively extraction at pH 2.3 was estimated as(C₁₇H₃₅NH₃)₂SO₄Fe(OH)SO₄ which was evidenced by elemental analysis and Uv spectrometry. Molecular weight measurement indicated that this complex existed in highly intermolecular associated form in benzene solution.

Key words: Complexation extraction, Iron, Organic amine, Mechanism