Kinetics and thermodynamics analysis of apple polyphenols adsorption by aminated magnetic chitosan microspheres

The aim of this study was to study the kinetics and thermodynamics of apple polyphenols adsorption by aminated magnetic chitosan microspheres. The pseudo-first-order kinetics model, pseudo-second-order kinetics model, Elovich equation and pore diffusion equation were used to fit the adsorption kinetics process. Three isothermal adsorption models (Langmuir, Freundlich and Temkin) were used to analysis adsorption thermodynamics properties. The results showed that adsorption kinetics process conformed to the pseudo-second-order kinetics model. Adsorption rate constant, initial adsorption rate and equilibrium adsorption content tended to increase with the increasing of the temperature, and adsorption amount was higher. Adsorption thermodynamics conformed to Freundlich isothermal adsorption model. The results of thermodynamic parameters ΔG was below zero, ΔH was above zero, and ΔS was above zero. Which indicated that the adsorption of apple polyphenols to aminated magnetic chitosan microspheres was a spontaneous and exothermic process with the increasing of entropy. The kinetics and thermodynamics process can provide technical basis for the adsorption process of apple polyphenols using aminated magnetic chitosan microspheres.