Selective separation of amino acids with a charged inorganic nanofiltration membrane: Effect of physicochemical parameters on selectivity
✍ Scribed by A. Garem; G. Daufin; J. L. Maubois; J. Léonil
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 190 KB
- Volume
- 54
- Category
- Article
- ISSN
- 0006-3592
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✦ Synopsis
A charged organic-inorganic nanofiltration (NF) membrane prototype was used to separate a mixture of nine amino acids (AA) on the basis of differential electrostatic interactions with the membrane because, for a given pH, some of them were positively charged, some were negative, and some were zwitterions. Effect of pH, amino acid concentration (C r ), and added ionic strength ([NaCl]) on the process selectivity was studied. A global statistical study revealed that pH was the dominant parameter regarding fractionation. C r and [NaCl] had a weaker effect, but the ratio C r /[NaCl] demonstrated a pronounced effect on system selectivity. Two split-ups of the mixture were obtained at pH 2 and at pH 12, for a 1-g/L total AA concentration and a C r /[NaCl] ratio of 0.16. Under these conditions, the differences in transmissions between basic and acid AA were higher than 70%. Interpretation of the results according to the Donnan theory allows us to foresee the potentialities of charged nanofiltration membranes for the fractionation of a complex mixture, such as peptidic hydrolysate to streams containing peptides and amino acids having different isoelectric points.