SELECTIVE REMOVAL OF COPPER FROM AN AQUEOUS-SOLUTION USING LIGAND-MODIFIED MICELLAR-ENHANCED ULTRAFILTRATION USING AN ALKYL-BETA-DIKETONE LIGAND

The semiequilibrium dialysis technique has been used to investigate th e concentration of Cu2+ using a water-insoluble liquid ion exchanger o r ligand with cationic surfactant in a ligand-modified micellar-enhanc ed ultrafiltration (LM-MEUF) process. In LM-MEUF the surfactant and th e ligand are added to an aqueous solution containing ions of like char ge, one of which needs to be selectively removed. The ligand forms a c omplex with the target ion of interest and solubilizes or dissolves in side the organic interior of the micelles. Therefore, it is possible t o replace typical solvent extraction solvents such as kerosene by mice lles. In this study copper chloride/calcium chloride solutions were tr eated for the extraction of copper using a commercially available liga nd, 1-phenyl-3-isoheptyl-1,3-propane dione in cetyltrimethylammonium b romide (CTAB), a cationic surfactant. The effect of pH and the concent rations of copper, calcium, surfactant, and ligand on the efficiency o f copper removal from water are discussed. Copper rejections greater t han 99% were obtained even in the presence of calcium. In studies of r egeneration of surfactant and ligand from the retentate stream contain ing rejected species, stripping of copper from the retentate was achie ved using sulfuric acid. Stripping efficiencies greater than 94% were attained in three to four stages, demonstrating the feasibility of thi s regeneration scheme.