Recovery by means of electrodialysis of an aromatic amino acid from a solution with a high concentration of sulphates and phosphates

Abstract

In the industrial obtention of D-a-p-hydroxyphenylglycine the separation of the amino acid is carried out by precipitation and during this process, a mother liquor is produced with a high salt content (phosphates and sulphates) and an amino acid concentration of approximately 120-150 mol.m-3. The disposal of this mother liquor not only suppose an environmental problem for its high salinity and COD (Chemical Oxygen Demand) content but also an economic lost due to the high price of the unrecoved amino acid. To avoid this problem an electrodialytic process has been developped that allow the recovery of 85% of the amino acid in the form of a low salinity stream with a salt content a 70% lower than that the initial mother liquor. This low salinity stream can beincorporated to the main process and in this way the amino acid can be recover.