Removal of levulinic acid from aqueous solutions by clay nano-adsorbents: equilibrium, kinetic, and thermodynamic data

Abstract

In this research, the removal of levulinic acid from aqueous solutions was examined by using clay nano-adsorbents, namely montmorillonite and Cloisite 20A. The batch adsorption experiments were exerted at a different contact time (30-210 min), initial levulinic acid concentrations (20-100 g L-1), adsorbent amounts (0.05-0.25 g), and temperatures (25-45 degrees C). The equilibrium, kinetic, and thermodynamic data were obtained by using the adsorption capacities of clay nano-adsorbents. It was found that Cloisite 20A exhibited a higher adsorption capacity than montmorillonite. Different adsorption isotherm and kinetic models were utilized to explain the adsorption mechanism and the parameters of these models were determined. Moreover, the thermodynamic analysis was performed to express the adsorption process. For the adsorption of levulinic acid on both clay nano-adsorbents, the adsorption equilibrium data were well represented by the Freundlich isotherm model and the adsorption kinetic data were well characterized by the pseudo-second-order kinetic model for the removal of levulinic acid by two clay nano-adsorbents.