An efficient liquid-liquid extraction method was developed for the removal of Cd2+, Ni2+, Pb2+, and Zn2+ from environmental waste using n-benzoyl-n-phenyl hydroxylamine (BPA). The effects of solvents, pH, stripping agents, extraction time, and interference of other ions on the recoveries were investigated. Study shows chloroform is the most efficient solvent for BPA and maximum extraction percentage of metals can be achieved by it. These metals can be quantitatively extracted between the pH 6.5-10. 1M HNO3, 4M HNO3, 1M HCl, and 5M HNO3 can be used as stripping agents to achieve the maximum percentage recovery of Cd2+, Ni2+, Pb2+, and Zn2+, respectively.
Keywords: Chloroform, heavy metals, liquid-liquid extraction, N-benzoyl-n-phenylhydroxylamine, optimization, solvent.