Recovery of gamma-aminobutyric acid (GABA) from reaction mixtures containing salt by electrodialysis

• ED was successfully used to separate GABA from NH4Cl containing mixtures.
• Highest separation efficiency obtained was >99%.
• A recycling strategy was established.
• NH4Cl was the most preferable electrolyte for green production.
• The process cost for separation was estimated to be $20.4/t.

During the chemical synthesis of gamma-aminobutyric acid (GABA), a large amount of ammonium chloride is generated and coexisted with the product. In this study, electrodialysis (ED) was employed to separate and recover GABA from reaction mixtures containing salts. The selection of membranes and electrolytes were investigated. Results indicated that the CJ-MA-3/CJ-MC-3 membrane was more suitable for ED operation. The highest desalination rate was observed at 99.29% with GABA loss rate less than 3%. To increase the GABA recovery rate, the lost GABA was mixed with fresh raw material and recycled for the next production loop. Results showed that this recycling strategy can be effectively carried out for only one time. The total energy consumption for GABA dry product was less than 500 kW h/t, which was much less than the conventional separation technologies. Naturally, industrial production of high purity gamma-aminobutyric acid by ED was not only energy efficient but also environmentally friendly.