Separation of Unsaturated Fatty Acid Methyl Esters by Solvent Extraction with Both Hydrophilic and Hydrophobic Membranes

Separation of oleic acid methyl ester/linolic acid methyl ester and oleic acid/linolic acid is carried out by membrane extraction with both hydrophilic and hydrophobic membranes. The hydrophilic and hydrophobic membranes used were hollow fiber types, and polar solution such as acetonitrile with 10 wt % water and organic solution such as heptane were fed inside the fiber and in the shell side, respectively. The polar solution containing unsaturated fatty acid methyl esters was fed to the center of the membrane extraction apparatus so that the apparatus had both an enriching section and a stripping section. By this feed method, higher membrane performances such as solute purity and recovery are obtained than in the case of feeding to the edge of the apparatus. When hydrophobic and hydrophilic membranes are used in the stripping and enriching sections, respectively, the superior membrane performances is obtained. Further, effects of flow rate of polar solution and the hydrophobic membrane length on themembrane performances are investigated. The membrane performances by this membrane extraction method are analyzed, and the calculation results are confirmed to be approximately in agreement with the experimental data.