Recovery of L-lysine from L-lysine monohydrochloride by ion substitution using ion-exchange membrane Original Research Article

Ion substitution electrodialysis (ISED) consisting of two anion-exchange membranes and one cation-exchange membrane was performed to achieve efficient production of L-lysine from L-lysine monohydrochloride. Several experimental parameters including the operation voltage, the L-Lys·HCl concentration, and the initial pH of L-Lys·HCl solution were compared and discussed in terms of ionic transport. The Cl− removal ratio, the current density, the current efficiency, and the energy consumption were presented and analyzed. When the initial concentration of L-Lys·HCl is 0.6 mol L− 1 and the constant voltage is 40 V, the removal ratio of Cl− reached 95.6%, the current efficiency 20.5% and the energy consumption 9.0 kW h kg− 1. Initial pH of L-Lys·HCl solution can affect the recovery ratio of L-Lys significantly. When the initial pH is kept at its isoelectric point, i.e. 9.74, the recovery ratio of L-Lys is to be maximized (93.2%). Elevating temperature can improve the electrodialysis process.