Heavy metal extraction with thiocarbamic-O-alkylesters

Two types of thiocarbamic-O-alkylesters, four bidentate ligands HL and one bis-bidentate ligand H2L, were used as extractants for heavy metal ions fro m aqueous solutions. Silver(I) was extracted as neutral complexes in a yiel d > 99 %. The underlying stoichiometry and the extraction constants are dis cussed. The extraction of silver(I) by the bis-bidentate ligand is signific antly more effective than the extraction by the analogous bidentate compoun d. In a dioxane/water mixture neutral, cationic and anionic silver complexe s were found by means of pAg and pH potentiometric titrations. The extracti on behavior is discussed with regard to the calculated stability constants.