Back extraction of lactic acid with microporous hollow fiber membrane

In this work, back extraction was considered a promising alternative to reg enerate carboxylic acids of low-volatility into appropriate aqueous solutio n from organic phase. Identification of an efficient back extraction system for lactic acid recovery was focused on. Screening of back extraction reag ents was first carried out by employing a wide variety of inorganic compoun ds. From the viewpoints of high stripping power, low cost and capability of simultaneously regenerating the extractant, aqueous sodium chloride soluti on was selected as the most suitable one for recovery of lactic acid from l actate-TOMAC (tri-n-octylmethylammonium chloride) complex. However, TOMAC a nd oleyl alcohol are likely to pose the troubling emulsion problem in conve ntional mixer-settler system. Therefore, non-dispersive back extraction of lactic acid from organic phase was attempted in a microporous hollow fiber (MHF) membrane device by aqueous NaCl solution. A satisfactory recovery was accomplished, signifying the great potential of integrating membrane back extraction with extractive fermentation process for lactic acid production. (C) 1999 Elsevier Science B.V. All rights reserved.