Sorption performance of light rare earth elements using zirconium titanate and polyacrylonitrile zirconium titanate ion exchangers

Lanthanum, cerium, neodymium, and samarium were sorption from aqueous solutions using zirconium titanate (ZrTi) and polyacrylonitrile zirconium titanate (PANZrTi) ion exchangers. The characterizations of prepared materials were performed using XRD, SEM, FTIR, TGA, and DTA techniques. The sorption behavior of various ions toward synthesized resin has been studied depending on reaction temperatures, pH values, and initial concentrations. The selectivity order found is Sm³⁺ > Nd³⁺ > Ce³⁺ > La³⁺ on ZrTi-100, Ce³⁺ > Sm³⁺ ≈ Nd³⁺ > La³⁺ on ZrTi-150, and Sm³⁺ ≈ Ce³⁺ > Nd³⁺ > La³⁺ on PANZrTi depending on the condition of prepared ZrTi samples. The K_d for lanthanide ions was slightly decreased with temperature increased, which indicated the exothermic nature. The sorption data obtained for equilibrium conditions have been analyzed using the different isotherm models, and the applicability of these isotherm equations was compared by the correlation coefficients, R². It was established that the equilibrium isotherm models’ applicability follows the order: Langmuir > Dubinin– Radushkevich > Freundlich. It is found the Ce³⁺ has high adsorption capacity on each of ZrTi-100 and ZrTi-150, while Nd³⁺ has high adsorption capacity on PANZrTi.