Facilitated transport of α-alanine and phenylalanine through sulfonic cation-exchange membranes Original Research Article

Facilitated transport of amino acid zwitterion (S) through sulfonic plane and tubular cation-exchange membranes (CEM) in a reactive form H+ is studied. This transport uses the ability of a non-charged species S to combine with H+ in order to form a counter-ion SH+ in the membrane. A theoretical model of the facilitated transport taking into account effect of the diffusion layers adjoining the membrane is developed. It is illustrated by the experimental results of α-alanine (Ala) and phenylalanine (Phe) transport through plane Nafion® 117 and Nafion® 120 membranes (Du Pont de Nemours), Ala transport through a plane CRP membrane (Rhône Poulenc®), and Ala transport through a tubular Nafion® 811X.