Flux and retention analysis during micellar enhanced ultrafiltration for the removal of phenol and aniline

Abstract

Studies were done for the removal of organic solutes under aqueous medium through micellar enhanced ultrafiltration (MEUF). The organic solutes selected for experiments consisted of an ionic compound (phenol) and a non-ionic compound (aniline); whereas cetyl pyridinium chloride (CPC), a counter-ionic surfactant was used for the formation of micelles under aqueous medium. UF was carried out under both stirred and unstirred conditions using batch cells. The effect of important operating parameters (applied pressure, solutes and surfactant bulk concentrations) on the extent of separation of the organic solutes were observed and studied. Solubilization of these solutes in CPC micelles were also experimentally ascertained. A mathematical model developed in this study was used to describe the separation of organic solutes by MEUF and predict permeate solute concentrations under varying operating conditions. The effect of pressure and feed CPC concentration on the behaviour of permeate flux was explained as a consequence of the formation of concentration polarized layer of CPC, upstream of the membrane surface. The removal of organic solutes (phenol and aniline) were observed to increase with increase in feed CPC concentration; however, upto about 150 mM, beyond which it was more or less constant. Solubilization equilibrium constant of phenol in CPC micelles was estimated to be around four times that of aniline.