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

Abstract

The present study synthesized magnetite-pectin-chitosan (MPC), which is a nanocomposite adsorbent through partial reduction co-precipitation method. Its structure and morphology were characterized by Scanning Electron Spectroscopy (SEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectrometry (FT-IR) and Vibrating Sample Magnetometry (VSM). One studied the adsorption of Lanthanum and Cerium ions onto MPC in a batch system as a function of initial pH of solution, contact time, initial concentration and temperature. When the initial pH of the solution increased, the La(III)/Ce(III) ions augmented as well. The optimum pH for La/Ce adsorption was 5 and the maximum adsorption achieved within 30 min. The thermodynamics parameters such as enthalpy (ΔH∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta {\ ext{H}}^\\circ$$\\end{document}), entropy (ΔS∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta {\ ext{S}}^\\circ$$\\end{document}) and Gibbs free energy changes (ΔG∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta {\ ext{G}}^\\circ$$\\end{document}) were calculated with the results suggesting 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 performed. Langmuir isotherm model enabled the data of adsorption to be described very well. The adsorption capacity was seen to be 8.17 mg/g and 9.72 mg/g for lanthanum and cerium, respectively. The adsorption kinetics of MPC indicated that the adsorption process fit the Pseudosecond-order (PSO) model. Based on these data, it is concluded that short operating time, eco-friendly technology, and easy to apply MPC can be used for La(III)/Ce(III) ions removal.