Removal of Chromium(VI) from Aqueous Solutions Using Fe₃O₄ Magnetic Polymer Microspheres Functionalized with Amino Groups

Kai Wang; Guangming Qiu; Hongyu Cao; Ruifa Jin

doi:10.3390/ma8125461

Removal of Chromium(VI) from Aqueous Solutions Using Fe₃O₄ Magnetic Polymer Microspheres Functionalized with Amino Groups

Materials (Basel). 2015 Dec 3;8(12):8378-8391. doi: 10.3390/ma8125461.

Authors

Kai Wang¹, Guangming Qiu², Hongyu Cao³, Ruifa Jin⁴

Affiliations

¹ Inner Mongolia Key Laboratory of Photoelectric Functional Materials, College of Chemistry and Chemical Engineering, Chifeng University, Chifeng 024000, China. kaiwang20151130@gmail.com.
² College of Energy and Power Engineering, Inner Mongolia University of Technology, Huhhot 010051, China. qiugm@imut.edu.cn.
³ Inner Mongolia Key Laboratory of Photoelectric Functional Materials, College of Chemistry and Chemical Engineering, Chifeng University, Chifeng 024000, China. hongyucao20151130@gmail.com.
⁴ Inner Mongolia Key Laboratory of Photoelectric Functional Materials, College of Chemistry and Chemical Engineering, Chifeng University, Chifeng 024000, China. ruifajin20151130@gmail.com.

Abstract

Magnetic polymer microspheres (MPMs) using glycidylmethacrylate (GMA) as a functional monomer were synthesized in the presence of Fe₃O₄ nanoparticles via dispersion polymerization. After polymerization, the magnetic polymer microbeads were modified with ethylenediamine (EDA). The obtained ethylenediamine-functionalized magnetic microspheres (EDA-MPMs) were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), vibrating-sample magnetometer (VSM) and Fourier transform infrared (FT-IR) spectroscopy. Then the EDA-MPMs were applied as adsorbents for the removal of Cr(VI) from aqueous solution. Langmuir equation was appropriate to describe the experimental data. The maximum adsorption capacities obtained from the Langmuir model were 236.9, 242.1 and 253.2 mg/g at 298, 308 and 318 K, respectively. The Cr(VI) adsorption equilibrium was established within 120 min and the adsorption kinetics was compatibly described by the pseudo-second order equation. The thermodynamic parameters (ΔG°, ΔH°, ΔS°) of the sorption process revealed that the adsorption was spontaneous and was an endothermic process. The regeneration study demonstrated that the EDA-MPMs could be repeatedly utilized with no significant loss of adsorption efficiency.

Keywords: adsorption; chromium(VI); isotherms; kinetic; magnetic polymer microspheres.