Removal of Cu2+, Cd2+ and Pb2+ from aqueous solutions by magnetic alginate microsphere based on Fe3O4/MgAl-layered double hydroxide

Junhao Sun; Yan Chen; Haiqin Yu; Liangguo Yan; Bin Du; Zhiguo Pei

doi:10.1016/j.jcis.2018.07.132

Removal of Cu²⁺, Cd²⁺ and Pb²⁺ from aqueous solutions by magnetic alginate microsphere based on Fe₃O₄/MgAl-layered double hydroxide

J Colloid Interface Sci. 2018 Dec 15:532:474-484. doi: 10.1016/j.jcis.2018.07.132. Epub 2018 Jul 31.

Authors

Junhao Sun¹, Yan Chen², Haiqin Yu¹, Liangguo Yan³, Bin Du¹, Zhiguo Pei⁴

Affiliations

¹ School of Water Conservancy and Environment, University of Jinan, Key Laboratory of Water Resources and Environmental Engineering in Universities of Shandong (University of Jinan), Jinan 250022, PR China.
² Longkou Environmental Protection Bureau, Longkou 265701, PR China.
³ School of Water Conservancy and Environment, University of Jinan, Key Laboratory of Water Resources and Environmental Engineering in Universities of Shandong (University of Jinan), Jinan 250022, PR China. Electronic address: chm_yanlg@ujn.edu.cn.
⁴ State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085, PR China.

PMID: 30103130
DOI: 10.1016/j.jcis.2018.07.132

Abstract

In this work, the magnetic alginate microsphere of Fe₃O₄/MgAl-LDH (Fe₃O₄/LDH-AM) was prepared by immobilizing the Fe₃O₄/LDH with calcium alginate (CA) and was used to remove Cd²⁺, Pb²⁺, and Cu²⁺ from aqueous solutions. The obtained Fe₃O₄/LDH-AM was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller surface area determination. The results indicated that the surface groups of the alginate and LDH were retained and so was the crystal structure in the alginate microsphere. The adsorption performance of the Fe₃O₄/LDH-AM for Cd²⁺, Pb²⁺, and Cu²⁺ in aqueous solutions was evaluated by batch and column adsorption experiments. The effects of adsorption conditions, kinetics, isotherms, mechanisms, and potential applications were investigated. The adsorption kinetic data conformed to the pseudo-second-order kinetic equation, and the isotherm data fit well with the Freundlich and Langmuir isotherm models. The adsorption mechanism of Cd²⁺, Pb²⁺, and Cu²⁺ by the Fe₃O₄/LDH-AM entailed complexation and precipitation. The experimental breakthrough curves were correlated with the Thomas model. Moreover, the Fe₃O₄/LDH-AM displayed superior regeneration and reusability. These results suggest that the Fe₃O₄/LDH-AM is an efficient adsorbent for the removal of heavy metals and can be effectively employed in practical applications.

Keywords: Adsorption mechanisms; Alginate microsphere; Column experiment; Heavy metals; Magnetite.