Removal of lanthanum and cerium from aqueous solution using chitosan-functionalized magnetite-pectin

Abstract

In this study magnetite-pectin-chitosan (MPC) nanocomposite was synthetized using a partial reduction co-precipitation method. The structure and morphology of the material were characterized by scanning electron spectroscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and vibrating sample magnetometry (VSM). The adsorption of Lanthanum and Cerium ions onto MPC was studied in a batch system as a function of initial pH of solution, contact time, initial concentration and temperature. The La(III)/Ce(III) ions was increased when the initial pH of the solution increased. The optimum pH for La/Ce adsorption was 5 and the maximum adsorption was reached within 30 min. The thermodynamics parameters such as enthalpy change (∆°H), entropy change (∆°S) and Gibbs free energy change (∆°G) were calculated. The results suggested that the adsorption was exothermic and spontaneous. To determine the adsorption characteristics, models of Langmuir, Dubinin-Radushkevich, Freundlich, Temkin and Flory-Huggins adsorption isotherms were applied. Langmuir isotherm model described the data of adsorption very well. The adsorption capacity was found to be 8.17 mg/g and 9.72 mg/g for lanthanum and cerium, respectively.