Effect of emulsion liquid membrane stability on Vanadium separation efficiency

Emulsion liquid membrane (ELM) processes for separation of chemical species from a mixture are gaining in importance and emerging as a viable alternative to conventional separation processes. However instability of ELM has more effect on separation efficiency and application of this method.Therefore, aim of this work was to study stability of emulsification parameters and the effect of these factors on the separation efficiency of vanadium (IV) ions from sulphoric acid solution. The membrane was prepared by dissolving the extractant which contained mixture of bis(2-ethylhexyl) phosphoric acid (D2EHPA) and mono (2-ethylhexyl) phosphoric acid (M2EHPA) (60:40% v/v). the hydrophobic surfactant sorbitan monooleate (Span 80), kerosene (diluent) and sulphoric acid solution (internal aqueous phase) have been apllied for emulsion membrane preparation. Effects of operating parameters such as emulsification time, emulsification speed, stirring speed, carrier and surfactant concentration, volume ratios of membrane phase to external aqueous phase to membrane (W/O) phase and internal phase concentration on the membrane stability and separation efficiency were studied. Most effective factor is kind of dilluent and concentration of surfactant is in second order of importance on both stability of membrane and separation efficiency. The obtained results indicated that this technique is most efficient for separation vanadium.