Journal of Chemical Engineering of Japan, Vol.47, No.4, 314-318, 2014
Permeation Mechanism of Succinic Acid through Polymer Inclusion Membranes with Ionic Liquid Aliquat 336
A separation method for succinic acid has been intensively studied for developing cost-effective and environmentally benign processes. In this study, we applied polymer inclusion membranes (PIMs) containing an ionic liquid, Aliquat 336, to the separation of succinic acid. PIMs are formed by casting a solution containing a carrier, plasticizer, and base polymer (poly(vinyl chloride)) to form a thin, flexible, and stable film. We found that succinate successfully permeated the PIM containing Aliquat 336 and observed the uphill transport using a feed solution with pH 4 and Na2CO3 solution as the stripping phase. PIMs show complex permeation behavior involving un-dissociated, mono-anionic, and di-anionic forms of succinic acid as the species permeated. The mono-anionic form of succinic acid showed the largest permeability among the three forms, with the optimum pH range for succinic acid permeation being approximately 4-5.