| Summary: | 碩士 === 元智大學 === 化學工程學系 === 93 === The recovery and separation of amino acids from aqueous solutions by using a hollow fiber membrane module have been studied in this paper. Due to the zwitterionic character of amino acids, they had specific isoelectric points (pI). Amino acids could exist as the cationic or anionic form by adjusting the pH value less and greater than their isoelectric points in aqueous solutions. Therefore, a cation-exchange carrier, D2EHPA, may be applied to extract anionic forms of amino acids and to separate two amino acids.
About the selectivity of binary amino acids, it was found that the larger the pH value, the larger the selectivity (1 < pH < 7). It was also found that the larger the concentration of D2EHPA in the organic phase, the larger the recovery.
The hollow fiber experiments were performed by changing the pH value, the D2EHPA concentration, the acidity of strip phase, the concentration ratio of L-phenylalanine and L-aspartic acid in the feed phase, and the flow rate of all phase. It was shown that an increase of D2EHPA concentration in the organic phase and the concentration of the acid in the strip phase would enhance the selectivity. The increase of pH value in the feed phase and the ratio of [Asp]aq/[Phe]aq in the feed phase would enhance separation factor. The selectivity was in the range 1.3 ~ 18.5 .
|
|---|
