Bertino A., Mazzeo L., Liberatore L., Della Posta S., Fanali C., Piemonte V., 2024, Polyphenols Recovery from Hazelnut Skin Wastes Through Extraction with a Water-ethanol Solvent Mixture: Equilibrium and Kinetic Studies, Chemical Engineering Transactions, 109, 19-24.
This study delves into the principles of the Circular Economy by focusing on the extraction of polyphenols from hazelnut skin wastes. The project’s innovation lies in the pioneering use of a 50% vol/vol water-ethanol mixture as a solvent for polyphenol extraction, within a custom batch set-up. The primary objective was to explore both equilibrium and kinetic aspects of this novel system. Initial experiments involved maintaining the solvent at 70°C for six hours to reach equilibrium, while varying solid/liquid ratios from 0.16 to 50 g/L. A fitting of the experimental data with an equilibrium modelling revealed values of ?? ?????? = 0.255 g/g and ??= 0.0092 L/g as the total amount of extractable polyphenols and the solid-liquid linear isotherm partition coefficient, respectively. Furthermore, kinetics of the extraction process was investigated across three different solid-liquid ratios (0.54, 1.00 and 2.00 g/L). Concentration measurements at different time intervals were fitted with the Linear Driving Force (LDF) kinetic model, allowing for the estimation of the LDF mass transfer coefficient ???? ?????? for each solid-liquid dosage. Notably, the thermodynamic and kinetic parameters derived in this study are unique, since they are specifically tailored to the utilization of a 50% vol/vol water-ethanol mixture as polyphenol extraction solvent. This research underscores the potential of utilizing such solvent mixtures in polyphenol extraction from biomass wastes, thereby contributing to the advancement of sustainable practices within the Circular Economy framework.
