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The adsorption behaviors of some oxime compounds well known as metal chelating agents on the Amberlite XAD resins were compared by measuring their distribution coefficients (log Kd) in various media, respectively. Among the oxime compounds, salicylaldoxime (SAO) and α-benzoinoxime(α-BzO) which showed large log Kd values were chosen. The characteristics of XAD-4 resins impregnated with SAO and α-BzO have been studied to apply them for the adsorption and recovery of minute quantities of metal ions in aqueous solution. The optimum conditions for adsorption of SAO and α-BzO on the resin were 30% methanol media having pH range of 1∼8(for SAO) and 1∼9 (for α-BzO), respectively. The distribution coefficients of two oxime compounds were decreased as temperature increased. From the adsorption enthalpy data of SAO and α-BzO, ranging from 4.96 to 6.66 Kcal/mol, it is suggested that their adsorption mechanism on XAD-4 resin is likely due to molecular adsorption equivalent to dipole-dipole interaction. The impregnated resins were considerably stable in the aqueous solutions of pH 5.0∼10.0 and in 0.1∼5M hydrochloric acid solutions. The former is the medium for adsorption of metal ions, while the latter is for recovery of the adsorbed metal ions. The adsorption mole ratio of Mn(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ) ions on SAO-XAD-4 and α-BzO-XAD-4 resins were about 1 : 2 at the optimum conditions, respectively. The adsorbed metal ions were recovered completely by eluting with 3M HCl-50% methanol solution.
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