Theoretical Investigations and Experimental Studies of the Adsorption of Diethyl Phthalate and Di(2-ethylhexyl) Phthalate on Reduced Graphene Oxide

Abstract

Through an eco-friendly solvothermal approach, a reduced graphene oxide (rGO) was successfully fabricated for the convenient removal of diethyl phthalate (DEP) and di(2-ethylhexyl) phthalate (DEHP) from water streams. The morphological and spectroscopical characterization of the prepared rGO was accomplished using SEM, FTIR, EDX and UV-visible spectroscopy. The adsorption properties of rGO was explored using static adsorption experiments. Kinetics, isotherms, thermodynamics and computational studies were performed to evaluate the adsorption process. The results disclosed that the experimental data were compatible with pseudo-second-order kinetics and the Freundlich adsorption isotherm. The kinetic diffusion model revealed that intraparticle diffusion is present but may not be the sole rate-limiting factor. Thermodynamic analysis indicated that the test adsorbent spontaneously adsorbed DEP and DEHP, driven mainly by entropy change. In the light of theoretical quantum studies, the frontier molecular orbitals, electrostatic surface potential and molecular reactivity parameters for the studied compounds were reported and discussed.