Monitoring kinetic and thermodynamic parameters of fluoride adsorption from aqueous solution by pks-based anion resins

Abstract

Fluoride is important for human health, but high level of fluoride concentrations can be threatening for both humans and animals as well as damaging to the environment. This paper delineates on fluoride adsorption onto palm kernel shell-based anion resins under various fluoride concentrations and temperatures. The equilibrium fluoride adsorption capacity demonstrated by the resins was observed 2.32 mg/g. Pseudo second-order model and Weber-Morris diffusion model were employed to evaluate the uptake rate and behavior of fluoride adsorption. The correlation coefficients (R2) between experimental data and pseudo second-order model predictions was almost unity at all concentrations (5, 10 and 15 mg/L), indicating goodness of fit of the model. On the other hand, the thermodynamic study revealed the endothermic nature of the process indicated by the positive value of enthalpy change (2.671 kJ/mol). Moreover, the process is dominantly physical in nature along with a slight contribution of chemisorption.

Keywords

• fluoride; kinetics; thermodynamics; palm kernel shells.