Extraction of bisphenol A from aqueous solutions by emulsion liquid membrane

In this work, the extraction of bisphenol A (BPA), an endocrine disrupting compound, from aqueous solutions by emulsion liquid membrane (ELM) was studied. Liquid membrane consists of a diluent (hexane) and a surfactant (Span 80). 0.05N sodium hydroxide solution was used as internal aqueous phase. Effects of experimental conditions that affect the stability such as surfactant concentration, emulsification time, internal phase concentration and volume ratio of internal phase to membrane phase was investigated. The important variables governing the permeation of BPA were examined. These variables are sulfuric acid concentration in external phase, acid type in external phase, internal phase concentration, type of internal phase, surfactant concentration, stirring speed, volume ratio of internal phase to membrane phase, treatment ratio, BPA concentration, diluent type and presence of salt. This study also investigated the effect of NaOH concentration in the internal phase on the stripping of BPA. The results showed that by appropriate selection of the extraction and stability conditions, it was possible to extract nearly all of BPA molecules from the feed solution even in the presence of high concentration of salt. Under optimum conditions, very good stripping efficiency (98%) can be achieved. (C) 2009 Elsevier B.V. All rights reserved.