Abstract:
The separation of D,L-phenylalanine from synthetic feed via a hollow fiber supported liquid membrane (HFSLM) was studied in this work. The feed and stripping solutions were fed counter-currently. The extractants were chiral extractant (O,O'-dibenzoyl-(2S,3S)-tartaric acid ((+)-DBTA)) and achiral extractants (di-2-ethylhexyl phosphoric acid (D2EHPA) and tricaprylylmethylammonium chloride or trioctylmethyl ammonium chloride (Aliquat 336)) dissolved in n-octanol. De-ionized water was used as a stripping solution. Other parameters were studied: the pH of feed solution, concentrations of pure extractants in liquid membrane phase, concentrations of the synergistic extractants of chiral and achiral, the volumetric flow rates of feed and stripping solutions, and initial concentration of D,L-phenylalanine in feed solution. From the results, L-phenylalanine was selectively separated by the synergistic extraction of chiral-to-achiral mixture (6 mM (+)-DBTA and 6 mM Aliquat 336) at equal volumetric ratio of 1:1, and the pH of feed solution 5.0 at equal volumetric flow rates of feed and stripping solutions of 100 ml/min. The highest percentages of extraction, stripping and enantiomeric excess (% e.e.) of L-phenylalanine were 98%, 93% and 80%, respectively. Furthermore, in this work a mass-transfer modeling of L-phenylalanine concentration with time can be used to calculate its maximum concentration. The model was validated as the theoretical values from the model were found to be in good agreement with the experimental results with approximately 2 % deviation.