Effect of pH on sorption for RE(III) and sorption behaviors of Sm(III) by D152 resin

The pH dependent sorption of rare earth ions （La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Y（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, Gd（Ⅲ）, Tb（Ⅲ）, Dy（Ⅲ）, Ho（Ⅲ）, Er（Ⅲ）, Lu（Ⅲ）, and Yb（Ⅲ）） from HAC-NaAC buffer solution at 298 K by D152 resin containing -COOH function groups were presented. The sorption behaviors of D152 resin for Sm（Ⅲ） were discussed as an example. The effects of operational conditions such as pH, temperature, and contact time were studied. The statically saturated sorption capacity was 510 mg/g resin at pH 6.70 in HAc-NaAc medium at 298 K. The sorption behaviors obeyed the Freundlich isotherm. The capacity value for column study was obtained by graphical integration as 495 mg/g resin. Thomas model was applied to experimental data to predict the breakthrough curve and to determine the characteristic parameters of the column useful for process design.

Sorption Behavior of D152 Resin for Lanthanum

The sorption and desorption properties of La(Ⅲ) on D152 resin were investigated. The influence of operational conditions such as La(Ⅲ) initial concentration, sorbent mass, temperature, solution initial pH and sorption kinetics of La(Ⅲ) were studied. The optimal pH for the sorption was found to be 6.70 in the HAc-NaAc system. The statically saturated sorption capacity is 463 mg·g-1 at 298 K in HAc-NaAc medium. The static sorption data fit to the Freundlich isotherm and Langmiur isotherm. The sorption rate constant is k298 K=1.73×10-5 s-1. The thermodynamic sorption parameters, enthalpy change ΔH, entropy change ΔS and free energy change ΔG298 K of D152 resin for La(Ⅲ) are 15.9 kJ·mol-1, 132 J·K-1·mol-1, -39.4 kJ·mol-1, respectively. Dynamic sorption and desorption experiments have been carried out with the column packed by D152 resin. La(Ⅲ) adsorbed on D152 resin can be quantificationally eluted and the elution percentage is up to 100%.