Effect of some operating variables on cobalt(II) transport across a bulk liquid membrane

Abstract An experimental study is presented on facilitated transport of cobalt(II) cations through a bulk liquid membrane containing di(2-ethylhexyl)phosphoric acid (D2EHPA). The effects on the kinetics of cobalt(II) transport of stirring rate of the receiving phase and its acidity, mobile carrier (D2EHPA) concentration, emulsifier (Span 80) concentration, initial cobalt concentration, interfacial area, and membrane thickness have been investigated. It has been found that cobalt transport increased with both stirring of the receiving phase and its acidity, while the presence of emulsifier reduced this transport, particularly at the membrane/receiving phase interface. Moreover, the mean cobalt transport rate was practically independent of membrane/feed solution interfacial area (under experimental conditions), while this rate substantially increased with the initial cobalt concentration in aqueous feed solution.