Thermodynamic study on the adsorption of tungstate by chlorine-type quaternary ammonium resin

In view of the lack of thermodynamic parameters in the ion exchange process of tungsten, the equilibrium data for the adsorption of tungstate by the chlorine-type quaternary ammonium resin at different temperatures were determined, and thus the thermodynamic parameters of the adsorption process were calculated. The results show that the adsorption equilibrium data accords with the Langmiur isothermal adsorption equation. When calculating the Langmiur model constant term, the fitting precision of the nonlinear fitting method to the experimental data is better than that of the linear fitting method. Furthermore, the adsorption of tungstate by chlorine-type quaternary ammonium resin is endothermic process, where ΔH is 13.505 kJ/mol, ΔS is 0.098 kJ/(mol·K) and ΔG(298) is -15.833 kJ/mol. Moreover, ΔG is smaller with the increase of temperature, which shows that the increase of temperature is favorable for obtaining larger capacity of tungsten adsorption, and the thermodynamic analysis is consistent with the experimental results.