Stabilization of supported liquid membranes by plasma polymerization surface coating

Plasma polymerization coating is shown to be an effective method for improving the stability of supported liquid membranes (SLM) containing LIX 984N for copper transport. Hexamethyldisiloxane and heptylamine were employed as monomers and hydrophobic microporous microfiltration membranes with pore sizes of 0.05–0.2 μm were used as substrates. Electronmicroscopy revealed that the plasma polymerization film mainly occurred on the surface of the microporous membranes. Preliminary results show that either coating can improve the stability of the polypropylene Accurel SLMs with a thickness of 150 μm. For a thin membrane such as the polypropylene Celgard 2500 with a thickness of 25 μm, the heptylamine coating on the stripping side provides better stability than on the feed side.