Membrane stability and enrichment of nickel in the liquid emulsion membrane process

The parameters affecting the stability of a liquid emulsion membrane (LEM) for enrichment of nickel were studied. The liquid membrane is made up of a carrier (di‐2‐ethylhexylphosphoric acid), organic diluent and an emulsifying agent (sorbitan monooleate). Swelling of the internal phase during extraction results in breakage of the emulsion. The role of pH is very important in the LEM process for extraction of nickel. A significant decrease in swelling was observed by maintaining the pH of the feed phase constant during extraction. A lower osmotic pressure difference between the external and internal phase brings about lower changes in the swelling and membrane breakdown. © 2000 Society of Chemical Industry