Multiple interactions on macroporous adsorption resins modified with ionic liquid

A comparative adsorption study was conducted on (-)-epigallocatechin gallate and (-)-epicatechin onto AB-8, chloromethyl/macroporous adsorption resin (chloromethyl/MAR), and ionic liquid/macroporous adsorption resin (ionic liquid/MAR) developed by our group. Equilibrium adsorption data showed that adsorption capacities of ionic liquid/MAR were superior to those of AB-8 and chloromethyl/MAR under the same conditions. Adsorption isotherms could be properly described by Langmuir isotherm, whereas adsorption kinetics curves obeyed pseudo-second-order model. Evaluated thermodynamic parameters revealed that adsorption was spontaneous and exothermic. The dynamic adsorption capacity of (-)-epigallocatechin gallate anionic liquid/MAR at 298 K was approximately 72.5 mg/g dry resin. The resin column can be effectively regenerated using methanol. Analysis of adsorption mechanism suggested that it's the large adsorption capacity was due to multiple adsorption interactions. Considering the excellent adsorption performance of ionic liquid/MAR, it has promising potential for the large-scale preliminary separation and purification of EGCG from tea extracts. (C) 2015 Elsevier B.V. All rights reserved.