Patent ID: 7850852

Claim:
A method for recovering an eluent, which comprises heating or optionally heating under reduced pressure, a breakthrough liquid which is discharged from a pressure tight column through an adsorption step of adsorbing a free amino acid contained in an amino acid-containing aqueous solution on the pressure tight column while the solution passes through the pressure tight column packed with a carbonate-type anion exchange column under elevated pressure, and/or an eluate which is discharged from the pressure tight column through an elution step comprising injecting an eluent liquid containing a hydrogen carbonate ion and/or carbonate ion under pressure into the pressure tight column under elevated pressure, eluting the amino acid adsorbed on the anion exchange resin, and simultaneously regenerating the anion exchange resin into the carbonate-type and from which the amino acid or a salt thereof is removed, to vaporize a carbonate ion, and acidic carbonate ion, or an ammonium ion to thereby recover the eluent as a carbon dioxide gas or an ammonia gas.