Characters of Kinetic and Equilibrium of Adsorption of Eu(III) by an Cation Exchange Resin

The sorption and desorption behaviors of Eu(III) from aqueous solutions with cation exchange resins containing carboxyl groups (D155 resin) were studied in terms of varied Eu(III) concentration, adsorbent dosage, pH, contact time and temperature. Batch shaking sorption experiments were carried out to evaluate the performance of D155 resin in the removal of Eu(III) from aqueous solutions. The loading of Eu(III) ions onto D155 resin was found to increase significantly with the initial Eu(III) concentration increasing. The sorption was strongly dependent on pH of the medium with enhanced sorption as the pH changes from 4.00 to 6.40.The concentration of Eu(III) in aqueous solution was determined by UV–visible spectrophotometer. The adsorption kinetics, tested with Lagergren-first-order model and pseudo-second-order model, showed better agreement with Lagergren-first-order kinetics. The suitability of the Freundlich and Langmuir adsorption models was also investigated for europium–sorbent system.The thermodynamic parameters such as ΔG, which were all negative, indicated that the adsorption of Eu(III) ions onto D155 resin was spontaneous and the positive value of ΔH showed that the adsorption was endothermic in nature. Eu(III) ions can be eluted by using the 0.5mol/L HCl solution. The surface characteristic of Eu(III) on D155 resin before and after adsorption was shown using IR spectroscopic technique. Therefore, it has a good potential of the removal of Eu(III) from aqueous solutions.