Removal of lead by an emulsion liquid membrane: Part I

An extensive study on removal of lead (II) from aqueous solution using an emulsion liquid membrane (ELM) technique is presented. The study has highlighted the importance of emulsion stability for maximizing the removal of lead (II). The ELM consists of di-(2-ethylhexyl) phosphoric acid as a carrier, commercial kerosene as organic solvent, span 80 as an emulsifying agent and sulphuric acid as stripping phase. The important factors studied which affect the ELM stability and removal of lead are emulsification time (5–30 min), emulsification speed (1000–3000 rpm); the concentrations of surfactant (2–12 % v/v), carrier (1–12 % v/v), internal phase (0.25–3 molar H2SO4) and the effect of volume ratio of the oil phase to the stripping aqueous phase (O/A) (0.3–3.5). The results showed that it is possible to remove 99–99.5% of lead after 5 min contact time by using ELM at the optimum operating conditions.