Effect of membrane preparation on the lifetime of supported liquid membranes

A new observation on the stability of supported liquid membranes (SLMs) is reported. Membranes prepared with ‘dry’ outer surfaces, free from organic wetting, were found to be more stable than the conventional SLM prepared with external surfaces wetted with a film of the organic membrane liquid phase. For copper transport the ‘dry’ surface SLM had a similar initial flux to the ‘wet’ surface SLM, and 2 to 4 times the flux after 100 h. Over a 50 h period the ‘dry’ SLM lost about 10% of its membrane liquid, whereas the ‘wet’ SLM lost about 50%. The difference is ascribed to the loss of membrane by emulsion formation at one of the aqueous-organic interfaces which would be greater for the ‘wet’ SLM with a continuous liquid film over the surface of the support.