Nd/Dy resolution by SPE-based elution chromatography with bis(2-ethylhexyl) phosphate (HDEHP)-impregnated fiber-packed bed

Bis(2-ethylhexyl) phosphate (HDEHP) as an acidic extractant was impregnated onto a polymer chain grafted onto a 6-nylon fiber at a density of 0.43 mol/kg-product. Neodymium and dysprosium ions loaded onto the fiber packed into a bed were separated by elution chromatography using 0.2, 0.3, and 1.5 M hydrochloric acid as an eluent. At various space velocities and loaded amounts, the HDEHP-impregnated fiber-packed bed exhibited a higher peak height and a narrower half width because of shorter diffusional mass-transfer path of ions and larger external area per volume. The leakage of HDEHP impregnated was found to be negligible.