Copper and uranyl extraction from aqueous solutions using bis-dithiophosphinate ligands have been characterized

Dithiophosphinate ligands with groups linked together by a bridging spacer to take advantage of a chelate effect for improved selectivity have been characterized. Extractions with each ligand were performed with the ligands dissolved in methylene chloride and the metal salts dissolved in aqueous phase at pH 4. H2L1 was found to have good differentiation between UO22+ and Gd3+, but only resulted in 50% extraction. H2L2 had lower selectivity; however, copper extractions approached 95% after 24 h.

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► Bis-dithiophophinite ligands for uranyl extraction proposed.
► H2L1 40% uranyl, 60% copper, 25% gadolinium extraction.
► H2L2 50% uranyl, 50% gadolinium, 95% copper extraction.