A comparative economic analysis of copper removal from water by ligand-modified micellar-enhanced ultrafiltration and by conventional solvent extraction

In ligand-modified micellar-enhanced ultrafiltration (LM-MEUF), a surfactant and a ligand are added to an aqueous solution containing ions of like charge. The ligand forms a complex with the target ion of interest and becomes incorporated in the micelle. This solution is then treated by an ultrafiltration process with membrane pore sizes small enough to reject the micelles and their solubilized metal-ligand complex. Previous studies have demonstrated the technical feasibility of LM-MEUF with copper rejection exceeding 99% with no removal of calcium using several different Ligands. The ability to regenerate the surfactant/ligand for reuse has also been shown. In this study, an economic analysis of LM-MEUF (with regeneration) for a 1x10(5) gal/day unit is reported. The effects of important parameters are investigated; including feed surfactant, ligand, and copper concentrations. The results from the sensitivity analysis are used to compare the cost of LM-MEUF for copper removal and recovery to the conventional copper solvent extraction process. The comparative economic analysis indicates a 17% higher capital and a 43% higher operating cost for LM-MEUF process compared to the solvent extraction process. (C) 1998 Elsevier Science B.V.