Separation and preconcentration of gallium(III), indium(III), and thallium(III) using new hydrazone-modified resin

Ga(III), In(III) and Tl(III) ions in the presence of different sulfate salts have been successfully separated using 1-(3,4-dihydroxybenzaldehyde)-2-acetylpyridiniumchloride hydrazone (DAPCH) loaded on Duolite C20 in batch and column modes. The obtained modified resin as well as the metal complexes was characterized by elemental analysis and infrared spectra. The extraction isotherms were determined at different pH values. Ga(III) and In(III) are sorbed from aqueous solution at pH 2.5 - 3.0 while Tl(III) is sorbed at 2.0. The stripping of the adsorbed ions can be carried out using different concentrations of HCl as eluent. The saturation sorption capacities of Ga(III), In(III) and Tl(III) were 0.82, 0.96 and 0.44 mmol g(-1), where the preconcentration factors are 150, 150 and 100, respectively. The metal(III):Duolite C20-DAPCH ratio was 1:2 for Tl(III) and 1:1 for In(III) and Ga(III). The loaded resin can be regenerated for at least 50 cycles. The utility of the modified resin was tested in aqueous samples and the results show an RSD value of < 5% reflecting their accuracy and reproducibility.