Selective separation of copper and nickel by membrane extraction using hydrophilic nanoporous ion-exchange barrier membranes

Hydrophilic nanoporous ion exchange barrier membrane, based on polyethersulfone (PES)/sulfonated polyphenylether sulfone ketone (SPPESK), was utilized for the pH dependent separation of copper and nickel ions with a commercial extractant, LIX84-I. The extraction and stripping performance of the membrane was demonstrated in a single stage membrane contactor as well as in an integrated extraction/stripping system. By adjusting the feed pH to 2.9, a complete separation of copper and nickel was achieved using the membrane contactors, where a copper flux of 1.10 × 10−8 mol/cm2 s was observed. In an extraction/stripping integrated sandwiched membrane extraction contactor, significantly higher copper flux was observed due to the coupling of copper stripping. In addition, the PES/SPPESK barrier membrane prevented the loss of the organic extractant, exhibiting high stability in 30 days dynamic test. The results indicated that the membrane extraction contactor system is of great potential for selective extraction of metal ions.