The removal of some rare earth elements from their aqueous solutions on by-pass cement dust (BCD)

The sorption behavior of yttrium (Y3+), neodymium (Nd3+), gadolinium (Gd3+), samarium (Sm3+) and lutetium (Lu3+) from their aqueous solutions by by-pass cement dust (BCD) has been investigated using a batch technique. The sorption on BCD was studied as a function of pH, shaking time, initial concentration, mass of BCD and temperature. It was found that the sorption capacity of BCD had the order of Lu3+ > Sm3+ > Y3+ > Gd3+ approximate to Nd3+ following Freundlich isotherm at the determined optimum conditions. The results also demonstrated that the sorption data fit well the pseudo-second-order kinetic model. Thermodynamic parameters such as Delta H degrees, Delta S degrees and Delta G degrees indicated that the sorption of the investigated REEs on BCD was endothermic, favored at high temperature and spontaneous in nature. (C) 2011 Elsevier B.V. All rights reserved.