Impregnation and Characterization of High Performance Extraction Columns for Separation of Metal Ions

Abstract

Impregnation behaviors of reverse-phase silica materials and C18-silica HPLC columns were studied using di-(2-ethylhexyl)phosphoric acid (HDEHP) as a model extractant. Initially, the adsorption efficiency of the ligand on different types of bulk particles was investigated using various concentration of HDEHP in different composition of methanol/water mixtures based on a batch technique. Subsequently, impregnation of HPLC columns was performed using the dynamic flow-through technique. The experimental data fitted well to the Langmuir model and the adsorption isotherms from the flow-through experiment were used to prepare extraction columns of different ligand densities. Finally, the impregnated columns were characterized and validated through HPLC separation of the lanthanides.

Keywords:

• Batch impregnation
• flow through impregnation
• adsorption isotherm
• ligand density
• di-(2-ethylhexyl) phosphoric acid
• lanthanides

ACKNOWLEDGEMENT

The authors wish to acknowledge the funding from the Research Council of Norway. The authors are also grateful to the anonymous reviewers whose comments and suggestions significantly improved the quality of the article.