Equilibrium and kinetic studies on the extraction of gadolinium(III) from nitrate medium by di‐2‐ethylhexylphosphoric acid in kerosene using a single drop technique

Abstract

AbstractThe liquid–liquid extraction of Gd(III) from aqueous nitrate medium was studied using di‐2‐ethylhexylphosphoric acid (HDEHP) in kerosene. On the basis of the slope analysis data, the composition of the extracted species was found to be [Gd A3(HA)] with the extraction equilibrium constant (Kex) = (1.48 ± 0.042) × 10−12 mol dm−3. The results of the effect of temperature on the value of the equilibrium extraction constant indicated the endothermic character of the extraction system. The kinetics of the forward extraction of Gd3+ from nitrate medium by HDEHP in kerosene was investigated using the single drop column technique. The rate of flux (mass transfer per unit area) was found to be proportional to [Gd(III)], [H2A2](o), [NO3−], and [H+]−1 in the liquid drop organic phase. The forward extraction rate constant, kf, was 2.24 × 10−3 m s−1 using the equation: Copyright © 2005 Society of Chemical Industry