Voltammetric and Transport Characteristics of Anion-Exchange Membranes during Electrodialysis of Solutions Containing Alkylaromatic Amino Acid and a Mineral Salt

The peculiarities of electrodialysis of an alkylaromatic amino acid-mineral salt solution (model solution of demineralization in a microbiological synthetic procedure) were considered. An analysis of the voltammetric characteristics (VACs) of the anion-exchange membranes showed that the alkylaromatic acid had no significant effect on the limiting state for inorganic ions in the concentration range under study. An addition of an amino acid, however, significantly changed the length of the plateau on the VAC in view of the partial transition of the membrane into the amino acid form accompanied by a decrease in the electric conductivity of the membrane and the adsorption of the aromatic compound on the surface, leading to its hydrophobization. The dependences of the alkylaromatic amino acid flows were correlated with the dependences of pH in the concentration section on the side with the anion-exchange membrane on the current density during electrodialysis, the start of the abrupt change in pH corresponds to the maximum phenylalanine (tyrosine) flow and the first inflection on the VAC.