Adsorption kinetics, isotherm and thermodynamics studies of flavones from Vaccinium Bracteatum Thunb leaves on NKA-2 resin

In this paper, the adsorption and desorption characteristics of flavones from Vaccinium Bracteatum Thunb leaves (VBTL) were investigated using NKA-2 resin to separate flavones from VBTL. Based on static experiments with NKA-2 resin, adsorption kinetics, isotherms and thermodynamics of flavones from VBTL on NKA-2 resin were investigated. Results showed that NKA-2 resin had a good adsorption and desorption performances for the adsorption of flavones from VBTL, the adsorption capacity of NKA-2 resin was 9.55 mg/g, the ratios of adsorption and desorption were 57.88% and 76.54%, respectively. It was found that the Freundlich isotherm model and the pseudo first-order model were suitable to characterize the process of adsorption. The values of thermodynamic parameters including the changes of Gibbs free energy (Delta G*), entropy (Delta S*) and enthalpy (Delta H*) demonstrated the process of adsorption was spontaneous and exothermic. The adsorption process was controlled by physical mechanism rather than chemical mechanism. (C) 2014 Elsevier B.V. All rights reserved.