Solvent Extraction of Copper (II) Ions Using Unmodified and Aromatic Amine Modified Red Onion Skin Extract

This study investigated the use of unmodified red onion skin extract (UROSE), aniline modified red onion skin extract (AmROSE) and 2-aminophenol modified red onion skin extract (APmROSE) for the extraction of copper (II) ions from aqueous media. The effect of pH, agitation time, ligand concentration and metal ion concentration on the percentage extraction were explored. The stoichiometric coefficients of the metal ions and the ligands (UROSE, AmROSE and APmROSE) in each extraction experiment were determined using slope analysis. The results revealed that the percentage extraction of copper (II) ions increased with increasing ligand concentration and agitation time and decreased with increasing initial concentration of copper (II) ions. The optimum pH for the extraction of copper (II) was found to be 6.77, 6.10 and 2.57 for UROSE, AmROSE and APmROSE respectively, while slope analysis showed that UROSE, AmROSE, and APmROSE ligands reacted with the metal ion in 1:1 molar ratio.