Integrated hybrid membrane systems—membrane extraction and pertraction coupled to a pervaporation process

The processes of membrane extraction (ME), and pertraction of metal cations with simultaneous pervaporation (PV) of water from an organic phase, were examined and compared. The continuous membrane extraction (CME) system comprised two contactors containing the cation exchange membranes (CEMs) and a liquid organic phase circulating between them. The pertraction process was performed in a system composed of two CEMs separating the flowing liquid membrane (FLM) from the external aqueous solutions. The organic phase of CME or FLM was additionally circulated through a PV module with a hydrophilic polymer membrane. The CME–PV and FLM–PV systems were tested with the use of Zn2+ extractants such as di-(2-ethylhexyl)phosphoric acid (D2EHPA) and bis(2,4,4-trimethylpenthyl) thiophosphinic acid (Cyanex 302). According to the experimental findings, coupling the ME or pertraction to the PV process allows the continuous and efficient removal of water from the organic liquid membrane phase. The studied systems were found to work steadily with maintaining their integrity and high selectivity.