Thermodynamic study of adsorption of catechin on ion exchange fiber

The adsorption of catechin by using self-made ion exchange fiber (IEF) adsorbent was studied. Equilibrium data for the adsorption of catechin from aqueous solutions by IEF adsorbent within the temperature range of 286-328 K and observed concentration range were obtained and correlated with the Langmuir-type and Freundlich-type isotherm equations. Freundlich adsorption isotherms and isosteric enthalpy of the adsorption of catechin indicated that the process of adsorption of catechin from aqueous solutions by IEF was an endothermic process. Estimations of the isosteric enthalpy of adsorption, free energy, and entropy of adsorption were reported, and the adsorption behavior was reasonably interpreted.