Sandwich liquid membrane in the separation and concentration of Cu++.

Some tests of mass transport on a sandwich liquid membrane (SwLM) for separation and concentration of Cu++ ion are reported and the results compared with the traditional supported liquid membrane (SLM) system both in terms of stability and flux. Moreover a chemical-physical model was developed evidencing the differences in the mass transport between the two systems studied. The obtained results showed an higher Cu++ flux in the SwLM (110.4 vs. 52.4 mmol/h.m2 referred to the effective pore surface) while lifetime was lower (6 vs. 15 h). The model evidenced a lower overall resistance to Cu++ ions transport through the SwLM than the SLM because the transport in the free solution did not suffer of the pores presence. Use of permanent hydrophilic membranes can improve the SwLM lifetime in view of industrial applications.