Abstract
Two modified melamine resins has been prepared and investigated, the modification process took place through the treatment with thiourea to produce R1 or tetraoxalyl ethylenediamine to produce R2. The adsorption behavior of the obtained resins towards Ag(I) and Cu(II) from their aqueous solutions has been studied using batch method. The obtained resins were tested for selective separation between Cu(II) and Ag(I) form their binary mixtures. Resin R1 showed high selectivity towards Ag(I) from Cu(II) solution, while R2 gave a promising results for the selective separation of Cu(II) from Ag(I) solution. Both kinetic and thermodynamic parameters of the adsorption process were obtained. Thermodynamic data indicated that the adsorption process is endothermic spontaneous reaction. Kinetic analysis showed that the adsorption of Ag(I) on R1 is perfectly fit pseudo-first order model, while the adsorption of Cu(II) on R2 is perfectly fit pseudo-second order one. The interaction mechanism between metal ion and active sites has been interpreted as chelation. Durability of resins was estimated from column studies. These parameters indicated that the prepared resins have a good efficiency for repeated use.