RECOVERY BY MEANS OF ELECTRODIALYSIS OF AN AROMATIC AMINO-ACID FROM ASOLUTION WITH A HIGH-CONCENTRATION OF SULFATES AND PHOSPHATES

In the industrial synthesis of D-alpha-p-hydroxyphenylglycine the sepa ration of the amino acid is carried out by precipitation. During this process, a mother liquor is produced with a high salt content (phospha tes and sulphates) and an amino acid concentration of approximately 0. 12-0.15 M. The disposal of this mother liquor not only causes an envir onmental problem due its high salinity and COD (chemical oxygen demand ) content but also an economic loss due to the high price of the unrec overed amino acid. To avoid this problem an electrodialytic process ha s been developed that allows the recovery of 85% of the amino acid in the form of a low salinity stream with a salt content 70% lower than t hat of the initial mother liquor. This low salinity stream can be inco rporated into the main process and in this way the amino acid can be r ecovered. (C) 1998 Elsevier Science B.V.