HEAVY METAL EXTRACTION WITH THIOCARBAMIC-O-ALKYLESTERS

ABSTRACT

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