Solvent Extraction of Some Lanthanides with Trioctylphosphine Oxide in Molten Paraffin Wax

摘要

The extraction behavior of Ln(Ⅲ) (Ln=Nd, Sm, Tb and Yb) with trioctylphosphine oxide (TOPO) in molten paraffin wax has been studied. The effect of pH, TOPO concentration, medium, stirring time and the amount of salts added on the distribution of lanthanides between two phases were investigated. Two different compositions Ln(H2O)s-2 (TOPO)2(OH)2NO3 (Ln=Nd and Sm) and Ln(H2O)s-1(TOPO)2(OH) (NO3)2 (Ln=Tb and Yb) were determined by slope analysis method. The equilibrium extraction constant Kex and PH1/2 value were calculated and the thermodynamic parameters were obtained from the dependence of Kex on the temperature.