Effect of Temperature on Equilibrium Adsorption of F(II) by Chitosan: Determination of Thermodynamic Parameters

In this study removal of Fe (II) by chitosan adsorbent was experimentally investigated in a batch system. The adsorbent dose and pH of the metal solution was fixed at 0.15 g and 4, respectively. Equilibrium and thermodynamic studies were performed at three different temperatures. Langmuir–Freundlich isotherm model were well fitted to the experimental data. According to Langmuir–Freundlich parameters, maximum uptake capacity of Fe (II) reduces from 80.27 to 41.74 mg g-1 while temperature increases from 20 ºC to 40 ºC. It was observed that the metal uptake capacity decreased with the increase in temperature which shows the exothermic nature of the process. The exothermic nature of Fe (II) adsorption on chitosan adsorbent was also confirmed by the calculated negative value of enthalpy change. Standard Gibbs free energy change was calculated using Langmuir equilibrium constant. The negative value of ΔGº shows the adsorption of Fe (II) on chitosan is spontaneous.

کلیدواژه ها:

Adsorption ، Fe (II) ، Chitosan ، Equilibrium ، Thermodynamics ، Temperature