Solid‐phase extraction and separation of heavy rare earths from chloride media using P227‐impregnated resins

Abstract A solid‐phase extraction resin SIRs‐P227/XAD‐7HP was prepared by impregnating extractant P227 onto macroporous resin XAD‐7HP beads. SIRs‐P227/XAD‐7HP beads were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) equipped with energy‐dispersive spectroscopy (EDS). The adsorption kinetics, particle size effect, adsorption isotherm, pH equilibrium –lg D relationship (where D is distribution coefficient), desorption, adsorption selectivity for heavy rare earths, and impurity ions were studied. The results showed that the adsorption kinetics of Lu(III) on the SIRs‐P227/XAD‐7HP beads fitted the Morris–Weber model best. The adsorbance decreased as the particle size increased. The pH equilibrium –lg D relationship fitted well with a straight line, and the slope was 1.56. The experimental data fitted well with Langmuir adsorption. The calculated maximum adsorption capacity was 23.8 mg·g −1 , while the experimental datum was 22.7 mg·g −1 at the given conditions. The adsorbed Lu(III) can be easily stripped by 0.1 mol·L −1 HCl. The adsorption selectivity of SIRs‐P227/XAD‐7HP for heavy REs exhibited the following order: Lu > Yb > Tm > Er > Ho. The adjacent heavy rare earth (RE) separation factors β Lu/Yb , β Yb/Tm , β Tm/Er , and β Er/Ho were 1.57, 3.00, 3.03, and 2.23, respectively, at liquid/solid ratio (L/S) equal to 3:20. The adsorption selectivity for impurity ions exhibited the following order: Fe > Lu > Tm > Zn > Mg > Ca > Ho > Co > Ni > Cu > Al.