Equilibrium, isotherms and kinetic studies of uranium sorption onto AlPO 4 -5 and SAPO-5 materials

Abstract

The present work deals with the investigation of the use of the elaborated aluminophosphate (AlPO 4 -5) and silico-aluminophosphate (SAPO-5) materials, in uranium sorption from aqueous solution and real effluents obtained from Nuclear Research Center of Draria, Algiers, Algeria. The surface charge and acidic-basic character of AlPO 4 -5 and SAPO-5 is investigated by the determination of point of zero charge. Batch adsorption experimental studies are carried out to evaluate the influence of initial uranium concentration, final solution pH, contact time, solid-to-liquid ratio and temperature. A maximum adsorption capacity of 61.96 and 74.10 mg/g was obtained for AlPO 4 -5 and SAPO-5 respectively, at pH 7 with an adsorbent ratio of 0.1/150 g/ml and an equilibrium time of 120 min. Kinetic models (pseudo-first order, pseudo-second order and Weber-Morris) are applied to find the mechanism for the removal of uranium ions, experimental data are analyzed by equilibrium models (Langmuir, Freundlich, Dubinin-Radushkevich and Temkin). Modeling sorption results show that uranium sorption is a chemical and endothermic process. The results showed that AlPO 4 -5 and SAPO-5 are effective materials for the removal of uranium (VI) ions.