Two insoluble extractant systems based on a derivated polystyrene have been prepared for the separation and recovery of Pd (II). Those functional polymers have been obtained by the incorporation of a phosphine sulphide on the Amberlite XE-305 chloromethylated polymer (macroporous polystyrene cross-linked with 4% of DVB, containing 4 mmol Cl/g). This incorporation has been made by either direct attachment to the polymer or through a tris-ethoxylated chain as spacer between the polymeric backbone and the phosphine sulphide unit to provide enhanced hydrophilic properties and to minimize the steric hindrance for the phosphine sulphide moiety. Adsorption of Pd (II) from chloride solutions have been studied for the different polymers prepared and by varying the composition of the metal solution solvent by using mixtures of aqueous-dioxane media. The results obtained include the determinations of polymer capacity for Pd (II), the rate of metal adsorption and the polymer-Pd (II) capacity to take up tryptophan or tyrosine in a buffered media at pH = 6.5. The increase of dioxane concentration in the mixed media provides an increase of the capacity and a faster kinetics for Pd (II) adsorption, in both polymers. The determination of capacity factors for the adsorption of amino acids (tryptophan and tyrosine) has been carried out under a variety of conditions. The observed differences on these parameters are a clear indication of the selectivity of the adsorption process.
|Journal||Reactive and Functional Polymers|
|Publication status||Published - 15 Jul 1999|