Adsorption Equilibria of Succinic Acid and Lactic Acid on Amberchrom CG300C Resin

Abstract

One of the prerequisites to the development of a simulated moving bed (SMB) or a temperature-gradient SMB process for separation of succinic acid and lactic acid is to obtain their adsorption equilibrium data on a properly selected adsorbent It was first found that an Amberchrom CG300C resin could function well as a qualified adsorbent for the separation processes of interest On the basis of the selected adsorbent, the single-component adsorption equilibria of succinic acid and lactic acid were measured using a staircase frontal analysis method over the temperature range of (30 to 50)degrees C and the liquid phase concentrations up to 10 g.L-1. The resultant adsorption data were correlated with the Langmuir and the bi-Langmuir adsorption models. For these two models, the effect of temperature on the Langmuir and the bi-Langmuir equilibrium constants was examined, which revealed that the adsorption of each acid onto Amberchrom CG300C was exothermic. Such a temperature effect was expressed mathematically, which was then incorporated into each model equation. The resultant temperature-dependent form of the model equation allowed accurate predictions of all the adsorption equilibrium data acquired over the investigated temperature range. The adsorption equilibrium data and the model parameters reported in this study will be of great value in the stage of designing the temperature gradient SMB process that is packed with the Amberchrom CG300C resin and targeted at separating succinic acid and lactic acid.