Removal of uranium(VI) from aqueous solutions by magnetic Schiff base: Kinetic and thermodynamic investigation

We prepared a magnetic Schiff base (ferroferric oxide/Schiff base composite) which could efficiently remove uranium(VI) ions from aqueous solutions. In this study, the effect of adsorption parameters such as pH value, adsorbent dose, shaking time, and temperature has investigated and optimized. It is found that the maximum adsorption capacity of the magnetic composite toward uranium(VI) is 94.30 mg g(-1) obtained at pH = 6.0, adsorbent dose = 0.02 g, contact time = 6 h and temperature = 25 degrees C. Both kinetics and thermodynamic parameters of the adsorption process are estimated. It is found that the pseudo-second-order model is more suitable for our experiment. These data show that the process is exothermic and spontaneous. The Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models have been applied to evaluate the removal efficiency and the data were correlated well with Langmuir model. The adsorbed uranium(VI) can be desorbed effectively (about 98.57%) by 0.1 M NaOH and the adsorption capacity is not significantly reduced after three cycles. Present study suggests that this magnetic Schiff base can be used as a potential adsorbent for sorption uranium(VI) and also provide a simple, fast separation method for removal of uranium(VI) ions from aqueous solution. (C) 2012 Elsevier B.V. All rights reserved.