Kinetics characteristics and thermodynamics analysis of soybean pods sterols extraction process

Abstract

In order to make full use of biomass resources and extract sterols from the waste soybean pods, the mass transfer characteristic of the extraction process with ethanol aqueous solution was explored. The relationships between sterols mass concentration in extracting solution and extraction temperature and extraction time were studied under appropriate ethanol concentration and liquid-solid ratio. The kinetics model fitting, the mass transfer characteristic parameters research and thermodynamic analysis of extraction process were carried out. The result showed that the extraction process could be described by a second order kinetic model. Within the research scope, with the increase of extraction temperature, the mass transfer rate constant increased from 0.286 9 mL min−1 mg−1 to 0.848 5 mL min−1 mg−1, the half life was reduced from 20.9 min to 6.5 min, the activation energy of extraction process was 27.73 kJ mol−1. The Gibbs free energies were all less than zero, indicating that the sterols extraction process was spontaneous. The enthalpy change was 33.18 kJ mol−1 and entropy change was 122.2 J mol−1 K−1 in the extraction process, the extraction process was an endothermic and entropy increases process. The research results could provide reference for the large-scale extraction of sterols from soybean pods.

Keywords

• Soybean pods
• Sterols
• Extraction
• Model
• Mass transfer characteristic parameters