Micellar‐enhanced ultrafiltration of chromate anion from aqueous streams

Abstract

Micellar-enhanced ultrafiltration can be used to remove multivalent anions or cations from aqueous streams. In the removal of chromate ions (CrOz-), the cationic surfactant hexadecylpyridinium chloride is added to the solution, and the chromate ions preferentially adsorb at the surface of the highly charged surfactant micelles. The solution is processed by ultrafiltration, using a membrane with pore sizes small enough to block the passage of the micelles and adsorbed ions. The permeate solution has a chromate concentration less than 0.1% that in the original stream. A new equilibrium model, combining the simple twophase polyelectrolyte theory of Oosawa with thermodynamic activity, material-balance, and charge-balance equations, successfully correlates ultrafiltration and equilibrium dialysis results for chromate solutions.

Use of Micellar-Enhanced Ultrafiltration at Low Surfactant Concentrations and with Anionic–Nonionic Surfactant Mixtures

“…These equations can be used in conjunction with mass balance equations (Eqs. [4]- [7]) written on a surfactant-only basis to determine the distribution and composition of the surfactant between the monomer and the micellar phases.…”

Resistance in series model for micellar enhanced ultrafiltration of eosin dye

“…In literature removal of water-soluble lower-molecular-weight organic compounds in aqueous media has been shown to be an effective method by applying MEUF [12,13]. Inorganic compounds such as chromate (CrO 4 ) −2 can also be removed satisfactorily by MEUF [14].…”

Use of Micellar Solutions as Draw Agents in Forward Osmosis

“…In MEUF, micelles electrostatically bind oppositely charged ions and also solubilize organic compounds. The MEUF process has been investigated using CPC for the removal of chromate [13] and haloacetic acids [14]; using SDS for the removal of cadmium [15] and zinc [16]; and using TX-100 for the removal of dimethyl itaconate [17] and alachlor [18]. Permeate flux and the effectiveness of surfactant retention are important parameters associated with MEUF investigations.…”