Separation of polyunsaturated fatty acid eaters by flowing liquid membranewith porous partition

A laboratory-constructed flowing liquid membrane apparatus with porous part ition (FLM) was applied to the separation of such polyunsaturated fatty aci d esters (PUFA-Ets) as eicosapentaenoic acid ethylester (EPA-Et) and docosa hexaenoic acid ethylester (DHA-Et) at 293 K. The hydrophilic porous membran e was used as a partition, and 2 M AgNO3 aqueous solution was used as a mem brane liquid. By using dodecane as a feed diluent and m-xylene as a recover y solution, PUFA-Ets were successfully separated from mixture of fatty acid esters. The recovery fraction of PUFA-Ets and the separation degree betwee n DHA-Et and EPA-Et were investigated; it increases with the velocity of me mbrane liquid and the flow path length in the module, while it decreased wi th the velocity of feed and recovery solution. The recovery fraction of DHA -Et reachs 60% with only 8 s-retention time by the continuous operation. Th e concentrations of the DHA-Et at the outlet of the module were simulated b ased on the mass transfer model, which gave nearly 85% recovery fraction wi th 30 s-retention time. These results show that a stable operation, a high recovery and a high throughput are realized by the FLM.