Recovery of amino acids from aqueous solution by reversible complexation with mixed organic extractants

Extraction equilibria are presented for reversible complexation of L-phenyl alanine by the liquid ion-exchange extractants, Aliquat 336 and di-2-(ethyl hexyl) phosphoric acid (DEHPA), in the diluent, methyl isobutyl ketone. Res ults are compared for extraction by each of the single extractants and a mi xed extractant system composed of equimolar amounts of Aliquat 336 and DEHP A. The mixed system displayed lower loading values by a factor of 3 than th e single-extractant systems; however, it was able to sustain uptake capacit y for pH values 1.8 to 9.2. A simple complexation model, based on the Law o f Mass Action, was employed to describe the experimental results.