Production of Lactobionic Acid from its Sodium Salt Solution by Ion-Exchange on a Commercial Strong Acid Resin: Kinetic Data and Modeling

Abstract

Lactobionic acid (LBA) is a high value added product obtained from lactose oxidation. Since this reaction should be conducted in alkaline media by adequate addition of a Na-, Ca- or K-base, the final product is a lactobionate salt solution instead of the acid form. In this study, the behavior of a strong cation exchange resin (AmberliteTM FPC23 H) for the production of a LBA solution from its sodium lactobionate salt (LBNa), was investigated. The sodium exchange efficiency was evaluated at three different temperatures (5, 25, and 35ºC). The resin exhibited a good performance in the removal of sodium from the LBNa solution. In all cases, sodium concentration in LBA solution was reduced below 5 mg/L. A complete sodium removal was achieved after about 30 min at 5ºC, and after circa 10 min at 25 and 35ºC. Various kinetic models were used for the evaluation of experimental ion-exchange kinetic data. The rate constants, transient capacities, and related correlation coefficients for each kinetic model were calculated and discussed. Results showed that the pseudo-second order and the reversible reaction models adequately describe the experimental kinetic data. The activation energies computed using the rate constants obtained with these models were 50.87 and 36.12 kJ/mol, respectively.