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

• NKA-2 resin had a good adsorption and desorption performances for the adsorption of flavones from VBTL.
• The Freundlich isotherm model and the pseudo first-order model were suitable to characterize the process of adsorption.
• The process of adsorption was spontaneous and exothermic.
• The adsorption process was controlled by physical mechanism rather than chemical mechanism.

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 (ΔG∗), entropy (ΔS∗) and enthalpy (ΔH∗) demonstrated the process of adsorption was spontaneous and exothermic. The adsorption process was controlled by physical mechanism rather than chemical mechanism.