1,3-Propanediol adsorption on a cation exchange resin: Adsorption isotherm, thermodynamics, and mechanistic studies

Abstract

1,3-Propanediol (1,3-PD) is widely used in cosmetics, foods, antifreezes, and polyester. A low-cost cation exchange resin, 001×7 H-form resin, was selected for 1,3-PD adsorption obtained from microbial fermentation of crude glycerol. The thermodynamics and kinetics of adsorption were studied. To identify the characteristics of the adsorption process, the influence of 1,3-PD concentration, temperature, and resin particle diameters was studied. The temperature dependence of the adsorption equilibrium in the range of 288 to 318 K was observed to satisfy the Langmuir isotherm well. The thermodynamic parameters, adsorption enthalpy, entropy, and Gibbs free energy, were determined as 36.2 kJ·moL-1, 160 mol-1·K-1, and -11.2 kJ·moL-1, respectively, which indicated that the adsorption was spontaneous and endothermic. The adsorption kinetics was accurately represented by the shell progressive model and indicated that the particle diffusion was the rate-limiting step. Based on the kinetic simulation, the rate constant of exchange (k0), order reaction (α), and the apparent activation energy reaction (Ea) were obtained as 3.11×10-3, 0.644, and 11.5 kJ·moL-1, respectively. This kinetic and thermodynamic analysis of 1,3-PD recovery presented in this article is also applicable for the separation of other polyols by resin adsorption, which will promote value-added utilization of glycerol. ? 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.