Highly efficiently selective separation of zirconium from scandium by TRPO modified adsorbent

Abstract

Scandium (Sc) and zirconium (Zr) often co-exists with each other and are difficult to separate effectively due to their similar behavior during separation. Herein, a series of adsorbents were synthesized by vacuum impregnation method for the separation of Sc and Zr. The results show that the Trialkylphosphine oxide silica-based modified adsorbent (TRPO/SiO2-P) has excellent adsorption selectivity (SFSc/Zr = 3694). It has fast adsorption and elution kinetics with equilibrium obtained within 30 min, and the adsorption matches the pseudo-second-order kinetic model and Langmuir isotherm model. Fourier transform infrared spectrometer (FT-IR), x-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) analysis showed that Sc and Zr was successfully adsorbed mainly through binding with P = O in Trialkylphosphine oxide (TRPO). Stoichiometry of Sc or Zr extraction by TRPO shows that one Sc or Zr combines with two TRPO molecules. In addition, the results of column experiments show that the separation and recovery of Sc and Zr can be achieved in the adsorption and elution stages, respectively, where the purity of Sc reaches 99.3 %. It shows the great potential of TRPO modified adsorbent for practical application in Sc and Zr dynamic separation process.