Adsorption equilibrium, kinetics and dynamic process of polyphenols from orange peel extract on mixed‐mode adsorption resin HD‐1

Abstract

BACKGROUNDThe extraction and separation of natural polyphenols are attractive. Many researchers used high‐speed counter‐current chromatography to separate and purify polyphenols. However, it requires a long operating time, a large amount of organic solvent consumption, and a high operating cost. In this work, the adsorption behaviors of polyphenols from the orange peel extract on mixed‐mode resins were studied. The adsorption capacities and selectivities of different resins to the main polyphenols in the extract including gallic acid, p‐coumaric acid, and ferulic acid were compared. The adsorption mechanism was analyzed by adsorption equilibrium and kinetics studies as well as molecular docking. The fixed‐bed adsorption was studied experimentally and theoretically.RESULTSHD‐1 resin had excellent adsorption selectivities among the resins. The yield of polyphenols from the orange peel by integrated extraction‐adsorption increased by 82.94% compared with that of extraction without adsorption. The adsorption isotherms agreed with Freundlich model. Dubinin‐Radushkevich model results indicated that the adsorption of gallic acid mainly depends on non‐electrostatic interaction. The adsorption of the other two polyphenols involves electrostatic and non‐electrostatic interaction. The adsorption kinetics curves accorded with pseudo‐second‐order model, and the adsorption rate of gallic acid was the highest among the polyphenols. Adsorption of polyphenols involves both physical adsorption and chemical adsorption. The breakthrough curves could be well simulated by Yoon‐Nelson and Thoms models. Significant differences exist in times for 50% breakthrough.CONCLUSIONThe mixed‐mode chromatography with HD‐1 resin as stationary phase is applicable to separate the polyphenols.This article is protected by copyright. All rights reserved.