Removal of Divalent Metal Cations and Their Mixtures from Aqueous Streams Using Micellar-Enhanced Ultrafiltration

ABSTRACT Micellar-enhanced ultrafiltration (MEUF) is a novel membrane-based separation technique that can be used to remove multivalent metal cations from aqueous streams. In this technique an anionic surfactant is added to the aqueous stream containing the metal cations to be removed. The surfactant forms highly charged aggregates called micelles onto which the metal cations adsorb or bind. The aqueous stream is then passed through an ultrafiltration membrane with pores small enough to block the passage of the micelles and adsorbed metal cations. In this study, MEUF has been shown to remove divalent cadmium, zinc, copper, and calcium ions and their mixtures with rejections of at least 96%. A previously developed equilibrium binding model describes the results successfully. Under reasonable conditions the flux rates are not substantially below that of pure water, indicating the feasibility of MEUF for industrial application.