Assessment of monoamide extractants and solid supports as new extraction chromatographic materials

The potential of monoamide-based extraction chromatographic materials for actinide recovery was assessed by monitoring uranium partitioning into six different materials. These materials were comprised of two solid supports (Amberlite XAD 4 and XAD 7) coated with one of three extractants: di-2-ethylhexyl butyramide (DEHBA), di-2-ethyhexyl isobutryamide (DEHiBA), or di-2-ethyhexyl acetylamide (DEHAA). This report considers differences in uranium partitioning depending on the solid support, extractant, aqueous phase conditions and amount of extractant coating on a given support. Studies indicate the acetyl amide extractant coated onto XAD 7 is a top candidate for further investigation. This is an interesting finding as the acetyl amide is not generally considered a particularly useful extractant for solvent extraction separations due to its tendency to form a third phase. This information contrasts the general paradigm that a given extractant can be equally useful for extraction chromatographic or solvent extraction separations and indicates that the development of future classes of extraction chromatographic materials should carefully consider the role of alkyl groups in their optimization. Additionally, the efficacy of the developed monoamide materials are compared with more classically utilized organophosphorous materials to consider opportunities for advancement in f-element separations. (C) 2016 Elsevier B.V. All rights reserved.